diff --git a/-xJjrPmguxI.txt b/-xJjrPmguxI.txt new file mode 100644 index 0000000000000000000000000000000000000000..36c968cc951472a16feb5cb64574dbbc730e366a --- /dev/null +++ b/-xJjrPmguxI.txt @@ -0,0 +1,7909 @@ +align:start position:0% + +the following content is provided by MIT + + align:start position:0% +the following content is provided by MIT + + + align:start position:0% +the following content is provided by MIT +open courseware under a Creative Commons + + align:start position:0% +open courseware under a Creative Commons + + + align:start position:0% +open courseware under a Creative Commons +license additional information about our + + align:start position:0% +license additional information about our + + + align:start position:0% +license additional information about our +license and MIT open courseware in + + align:start position:0% +license and MIT open courseware in + + + align:start position:0% +license and MIT open courseware in +general is available at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu all right so uh today we're + + align:start position:0% +ocw.mit.edu all right so uh today we're + + + align:start position:0% +ocw.mit.edu all right so uh today we're +continuing in oxidation reduction and so + + align:start position:0% +continuing in oxidation reduction and so + + + align:start position:0% +continuing in oxidation reduction and so +we started this a little bit last week + + align:start position:0% +we started this a little bit last week + + + align:start position:0% +we started this a little bit last week +and we talked about uh briefly about + + align:start position:0% +and we talked about uh briefly about + + + align:start position:0% +and we talked about uh briefly about +balancing equations which as you recall + + align:start position:0% +balancing equations which as you recall + + + align:start position:0% +balancing equations which as you recall +is really about counting so it's not uh + + align:start position:0% +is really about counting so it's not uh + + + align:start position:0% +is really about counting so it's not uh +an intellectually challenging topic and + + align:start position:0% +an intellectually challenging topic and + + + align:start position:0% +an intellectually challenging topic and +just requires uh you know making sure + + align:start position:0% +just requires uh you know making sure + + + align:start position:0% +just requires uh you know making sure +that you've counted everything + + align:start position:0% +that you've counted everything + + + align:start position:0% +that you've counted everything +appropriately so you have to be a little + + align:start position:0% +appropriately so you have to be a little + + + align:start position:0% +appropriately so you have to be a little +bit careful but doing it but it's really + + align:start position:0% +bit careful but doing it but it's really + + + align:start position:0% +bit careful but doing it but it's really +not too hard so being able to balance + + align:start position:0% +not too hard so being able to balance + + + align:start position:0% +not too hard so being able to balance +oxidation reduction equations then + + align:start position:0% +oxidation reduction equations then + + + align:start position:0% +oxidation reduction equations then +allows you to go on and do the to talk + + align:start position:0% +allows you to go on and do the to talk + + + align:start position:0% +allows you to go on and do the to talk +about the things that we'll be talking + + align:start position:0% +about the things that we'll be talking + + + align:start position:0% +about the things that we'll be talking +about today so today we're going to + + align:start position:0% +about today so today we're going to + + + align:start position:0% +about today so today we're going to +cover electrochemical cells fad law and + + align:start position:0% +cover electrochemical cells fad law and + + + align:start position:0% +cover electrochemical cells fad law and +the relationship between Delta G and uh + + align:start position:0% +the relationship between Delta G and uh + + + align:start position:0% +the relationship between Delta G and uh +cell potential so everyone could quiet + + align:start position:0% +cell potential so everyone could quiet + + + align:start position:0% +cell potential so everyone could quiet +down a little bit I can hear a lot of uh + + align:start position:0% +down a little bit I can hear a lot of uh + + + align:start position:0% +down a little bit I can hear a lot of uh +noise in the background I realize you're + + align:start position:0% +noise in the background I realize you're + + + align:start position:0% +noise in the background I realize you're +still settling down and pulling out your + + align:start position:0% +still settling down and pulling out your + + + align:start position:0% +still settling down and pulling out your +notes um so as as I've mentioned all the + + align:start position:0% +notes um so as as I've mentioned all the + + + align:start position:0% +notes um so as as I've mentioned all the +way through the lectures I've given so + + align:start position:0% +way through the lectures I've given so + + + align:start position:0% +way through the lectures I've given so +far that you have to remember all the + + align:start position:0% +far that you have to remember all the + + + align:start position:0% +far that you have to remember all the +things you've learned because they're + + align:start position:0% +things you've learned because they're + + + align:start position:0% +things you've learned because they're +going to come back again so today we'll + + align:start position:0% +going to come back again so today we'll + + + align:start position:0% +going to come back again so today we'll +be back to thermodynamics and talking + + align:start position:0% +be back to thermodynamics and talking + + + align:start position:0% +be back to thermodynamics and talking +about spontaneous reactions in Delta G + + align:start position:0% +about spontaneous reactions in Delta G + + + align:start position:0% +about spontaneous reactions in Delta G +so this all ties in together this un + + align:start position:0% +so this all ties in together this un + + + align:start position:0% +so this all ties in together this un +these units are really more applications + + align:start position:0% +these units are really more applications + + + align:start position:0% +these units are really more applications +of things that you've already learned in + + align:start position:0% +of things that you've already learned in + + + align:start position:0% +of things that you've already learned in +the first half of the + + align:start position:0% +the first half of the + + + align:start position:0% +the first half of the +course and currently we're in in chapter + + align:start position:0% + + + + align:start position:0% + +12 so an electrochemical cell what is an + + align:start position:0% +12 so an electrochemical cell what is an + + + align:start position:0% +12 so an electrochemical cell what is an +electric chemical cell uh well it's any + + align:start position:0% +electric chemical cell uh well it's any + + + align:start position:0% +electric chemical cell uh well it's any +device in which you have an electric + + align:start position:0% +device in which you have an electric + + + align:start position:0% +device in which you have an electric +current and electric current is just the + + align:start position:0% +current and electric current is just the + + + align:start position:0% +current and electric current is just the +flow of electrons through a circuit and + + align:start position:0% +flow of electrons through a circuit and + + + align:start position:0% +flow of electrons through a circuit and +it's either the current is either + + align:start position:0% +it's either the current is either + + + align:start position:0% +it's either the current is either +produced by a a spontaneous reaction see + + align:start position:0% +produced by a a spontaneous reaction see + + + align:start position:0% +produced by a a spontaneous reaction see +where Delta G is going to come into this + + align:start position:0% +where Delta G is going to come into this + + + align:start position:0% +where Delta G is going to come into this +it's either produced by spontaneous + + align:start position:0% +it's either produced by spontaneous + + + align:start position:0% +it's either produced by spontaneous +reaction or used to bring about a + + align:start position:0% +reaction or used to bring about a + + + align:start position:0% +reaction or used to bring about a +non-spontaneous reaction so you can use + + align:start position:0% +non-spontaneous reaction so you can use + + + align:start position:0% +non-spontaneous reaction so you can use +uh an electrochemical cell to force a + + align:start position:0% +uh an electrochemical cell to force a + + + align:start position:0% +uh an electrochemical cell to force a +non-spontaneous reaction to go so a + + align:start position:0% +non-spontaneous reaction to go so a + + + align:start position:0% +non-spontaneous reaction to go so a +battery which most of you are are + + align:start position:0% +battery which most of you are are + + + align:start position:0% +battery which most of you are are +familiar with and Ed in many of uh the + + align:start position:0% +familiar with and Ed in many of uh the + + + align:start position:0% +familiar with and Ed in many of uh the +gadgets that you have is really just a + + align:start position:0% +gadgets that you have is really just a + + + align:start position:0% +gadgets that you have is really just a +collection of these uh electrochemical + + align:start position:0% +collection of these uh electrochemical + + + align:start position:0% +collection of these uh electrochemical +cells + + align:start position:0% +cells + + + align:start position:0% +cells +and as we'll see um perhaps at the end + + align:start position:0% +and as we'll see um perhaps at the end + + + align:start position:0% +and as we'll see um perhaps at the end +of today's lecture or next time that all + + align:start position:0% +of today's lecture or next time that all + + + align:start position:0% +of today's lecture or next time that all +these principles that you're learning + + align:start position:0% +these principles that you're learning + + + align:start position:0% +these principles that you're learning +about oxidation reduction apply to + + align:start position:0% +about oxidation reduction apply to + + + align:start position:0% +about oxidation reduction apply to +oxidation reaction reactions that happen + + align:start position:0% +oxidation reaction reactions that happen + + + align:start position:0% +oxidation reaction reactions that happen +in your body so the same same principles + + align:start position:0% +in your body so the same same principles + + + align:start position:0% +in your body so the same same principles +that apply for a battery apply for uh + + align:start position:0% +that apply for a battery apply for uh + + + align:start position:0% +that apply for a battery apply for uh +chemical reactions that are in your body + + align:start position:0% +chemical reactions that are in your body + + + align:start position:0% +chemical reactions that are in your body +that are important for human health so + + align:start position:0% +that are important for human health so + + + align:start position:0% +that are important for human health so +we'll talk about that as + + align:start position:0% +we'll talk about that as + + + align:start position:0% +we'll talk about that as +well so here is a example of an + + align:start position:0% +well so here is a example of an + + + align:start position:0% +well so here is a example of an +electrochemical set this is a pretty + + align:start position:0% +electrochemical set this is a pretty + + + align:start position:0% +electrochemical set this is a pretty +simple electrochemical cell so we have h + + align:start position:0% +simple electrochemical cell so we have h + + + align:start position:0% +simple electrochemical cell so we have h +two two beakers here and uh we have + + align:start position:0% +two two beakers here and uh we have + + + align:start position:0% +two two beakers here and uh we have +electrodes which are connected uh by + + align:start position:0% +electrodes which are connected uh by + + + align:start position:0% +electrodes which are connected uh by +wires and they're connected to something + + align:start position:0% +wires and they're connected to something + + + align:start position:0% +wires and they're connected to something +that can read the uh current that's + + align:start position:0% +that can read the uh current that's + + + align:start position:0% +that can read the uh current that's +coming through the system there's also a + + align:start position:0% +coming through the system there's also a + + + align:start position:0% +coming through the system there's also a +salt bridge which we'll talk about in a + + align:start position:0% +salt bridge which we'll talk about in a + + + align:start position:0% +salt bridge which we'll talk about in a +few minutes so this would be a fairly uh + + align:start position:0% +few minutes so this would be a fairly uh + + + align:start position:0% +few minutes so this would be a fairly uh +simple one that one could construct and + + align:start position:0% +simple one that one could construct and + + + align:start position:0% +simple one that one could construct and +uh I like to joke about you know what + + align:start position:0% +uh I like to joke about you know what + + + align:start position:0% +uh I like to joke about you know what +people would say in the old days when I + + align:start position:0% +people would say in the old days when I + + + align:start position:0% +people would say in the old days when I +go and do uh fundraising stuff for Mi + + align:start position:0% +go and do uh fundraising stuff for Mi + + + align:start position:0% +go and do uh fundraising stuff for Mi +and meet uh alumni that graduated from + + align:start position:0% +and meet uh alumni that graduated from + + + align:start position:0% +and meet uh alumni that graduated from +this place a really long time ago and + + align:start position:0% +this place a really long time ago and + + + align:start position:0% +this place a really long time ago and +they probably say well yeah before we + + align:start position:0% +they probably say well yeah before we + + + align:start position:0% +they probably say well yeah before we +could even do our problem sets you know + + align:start position:0% +could even do our problem sets you know + + + align:start position:0% +could even do our problem sets you know +we had to make our own batteries to be + + align:start position:0% +we had to make our own batteries to be + + + align:start position:0% +we had to make our own batteries to be +able to uh get some electricity to see + + align:start position:0% +able to uh get some electricity to see + + + align:start position:0% +able to uh get some electricity to see +by so uh we don't your your life is a + + align:start position:0% +by so uh we don't your your life is a + + + align:start position:0% +by so uh we don't your your life is a +bit simpler now you should hear some of + + align:start position:0% +bit simpler now you should hear some of + + + align:start position:0% +bit simpler now you should hear some of +the the old stories of what MIT students + + align:start position:0% +the the old stories of what MIT students + + + align:start position:0% +the the old stories of what MIT students +had to go through all right so this is a + + align:start position:0% +had to go through all right so this is a + + + align:start position:0% +had to go through all right so this is a +schematic view of what you just saw and + + align:start position:0% +schematic view of what you just saw and + + + align:start position:0% +schematic view of what you just saw and +we'll walk through and talk about all + + align:start position:0% +we'll walk through and talk about all + + + align:start position:0% +we'll walk through and talk about all +the different parts of the + + align:start position:0% +the different parts of the + + + align:start position:0% +the different parts of the +electrochemical cell + + align:start position:0% +electrochemical cell + + + align:start position:0% +electrochemical cell +so this uh again I drew this this + + align:start position:0% +so this uh again I drew this this + + + align:start position:0% +so this uh again I drew this this +actually myself I think actually I stole + + align:start position:0% +actually myself I think actually I stole + + + align:start position:0% +actually myself I think actually I stole +maybe parts of it or I draw the whole + + align:start position:0% +maybe parts of it or I draw the whole + + + align:start position:0% +maybe parts of it or I draw the whole +thing I can't quite remember but um + + align:start position:0% +thing I can't quite remember but um + + + align:start position:0% +thing I can't quite remember but um +again this is my despic of the beaker as + + align:start position:0% +again this is my despic of the beaker as + + + align:start position:0% +again this is my despic of the beaker as +I've mentioned in the past art was + + align:start position:0% +I've mentioned in the past art was + + + align:start position:0% +I've mentioned in the past art was +really not my strength so this is a + + align:start position:0% +really not my strength so this is a + + + align:start position:0% +really not my strength so this is a +beaker over here filled with liquid in + + align:start position:0% +beaker over here filled with liquid in + + + align:start position:0% +beaker over here filled with liquid in +this case uh we have ions dissolved in + + align:start position:0% +this case uh we have ions dissolved in + + + align:start position:0% +this case uh we have ions dissolved in +uh the solution we have zinc plus two + + align:start position:0% +uh the solution we have zinc plus two + + + align:start position:0% +uh the solution we have zinc plus two +and um and sulfate dissolved another + + align:start position:0% +and um and sulfate dissolved another + + + align:start position:0% +and um and sulfate dissolved another +Beaker over here uh in this in this + + align:start position:0% +Beaker over here uh in this in this + + + align:start position:0% +Beaker over here uh in this in this +Beaker we have a zinc electrode and this + + align:start position:0% +Beaker we have a zinc electrode and this + + + align:start position:0% +Beaker we have a zinc electrode and this +is at the anode and so this is zinc + + align:start position:0% +is at the anode and so this is zinc + + + align:start position:0% +is at the anode and so this is zinc +solid a piece of zinc solid stuck into + + align:start position:0% +solid a piece of zinc solid stuck into + + + align:start position:0% +solid a piece of zinc solid stuck into +this Beaker where you have uh the + + align:start position:0% +this Beaker where you have uh the + + + align:start position:0% +this Beaker where you have uh the +solution there's a wire connecting two + + align:start position:0% +solution there's a wire connecting two + + + align:start position:0% +solution there's a wire connecting two +electrodes on the other side we have the + + align:start position:0% +electrodes on the other side we have the + + + align:start position:0% +electrodes on the other side we have the +cathode and this is made of copper solid + + align:start position:0% +cathode and this is made of copper solid + + + align:start position:0% +cathode and this is made of copper solid +and it's sitting in a beaker that has a + + align:start position:0% +and it's sitting in a beaker that has a + + + align:start position:0% +and it's sitting in a beaker that has a +copper plus two and also sulfate in it + + align:start position:0% +copper plus two and also sulfate in it + + + align:start position:0% +copper plus two and also sulfate in it +and so uh let's look at what would + + align:start position:0% +and so uh let's look at what would + + + align:start position:0% +and so uh let's look at what would +happen if this reaction were to run so + + align:start position:0% +happen if this reaction were to run so + + + align:start position:0% +happen if this reaction were to run so +over here uh at the anode we have zinc + + align:start position:0% +over here uh at the anode we have zinc + + + align:start position:0% +over here uh at the anode we have zinc +solid being oxidized to zinc plus two so + + align:start position:0% +solid being oxidized to zinc plus two so + + + align:start position:0% +solid being oxidized to zinc plus two so +the reaction is is shown down here so + + align:start position:0% +the reaction is is shown down here so + + + align:start position:0% +the reaction is is shown down here so +this electrode actually gets consumed + + align:start position:0% +this electrode actually gets consumed + + + align:start position:0% +this electrode actually gets consumed +during the reaction you actually have + + align:start position:0% +during the reaction you actually have + + + align:start position:0% +during the reaction you actually have +solid being converted to zinc plus two + + align:start position:0% +solid being converted to zinc plus two + + + align:start position:0% +solid being converted to zinc plus two +uh in solution so you have a change in + + align:start position:0% +uh in solution so you have a change in + + + align:start position:0% +uh in solution so you have a change in +phase and as that happens two electr are + + align:start position:0% +phase and as that happens two electr are + + + align:start position:0% +phase and as that happens two electr are +generated from that reaction and the El + + align:start position:0% +generated from that reaction and the El + + + align:start position:0% +generated from that reaction and the El +electrons then will go through the wire + + align:start position:0% +electrons then will go through the wire + + + align:start position:0% +electrons then will go through the wire +and the current will be red they'll go + + align:start position:0% +and the current will be red they'll go + + + align:start position:0% +and the current will be red they'll go +through the wire over to the Copper + + align:start position:0% +through the wire over to the Copper + + + align:start position:0% +through the wire over to the Copper +solid and over here they'll pass into + + align:start position:0% +solid and over here they'll pass into + + + align:start position:0% +solid and over here they'll pass into +this Beaker and the electrons will find + + align:start position:0% +this Beaker and the electrons will find + + + align:start position:0% +this Beaker and the electrons will find +the copper plus two as shown in this + + align:start position:0% +the copper plus two as shown in this + + + align:start position:0% +the copper plus two as shown in this +equation down here and this will form + + align:start position:0% +equation down here and this will form + + + align:start position:0% +equation down here and this will form +copper solid so you're actually going to + + align:start position:0% +copper solid so you're actually going to + + + align:start position:0% +copper solid so you're actually going to +have copper extra copper pleating onto + + align:start position:0% +have copper extra copper pleating onto + + + align:start position:0% +have copper extra copper pleating onto +the electrode so this electrode is going + + align:start position:0% +the electrode so this electrode is going + + + align:start position:0% +the electrode so this electrode is going +to get bigger + + align:start position:0% +to get bigger + + + align:start position:0% +to get bigger +uh and this one will be consumed in the + + align:start position:0% +uh and this one will be consumed in the + + + align:start position:0% +uh and this one will be consumed in the +course of the + + align:start position:0% +course of the + + + align:start position:0% +course of the +reaction and so this is a a little + + align:start position:0% +reaction and so this is a a little + + + align:start position:0% +reaction and so this is a a little +picture over here the electrons coming + + align:start position:0% +picture over here the electrons coming + + + align:start position:0% +picture over here the electrons coming +into the copper solid finding the copper + + align:start position:0% +into the copper solid finding the copper + + + align:start position:0% +into the copper solid finding the copper +plus two and the copper plus two then is + + align:start position:0% +plus two and the copper plus two then is + + + align:start position:0% +plus two and the copper plus two then is +reduced um at the cathode to Copper + + align:start position:0% +reduced um at the cathode to Copper + + + align:start position:0% +reduced um at the cathode to Copper +solid and the blow up on the other side + + align:start position:0% +solid and the blow up on the other side + + + align:start position:0% +solid and the blow up on the other side +shows the copper solid uh once electrons + + align:start position:0% +shows the copper solid uh once electrons + + + align:start position:0% +shows the copper solid uh once electrons +leave uh say the zinc solid electrons + + align:start position:0% +leave uh say the zinc solid electrons + + + align:start position:0% +leave uh say the zinc solid electrons +leave you form Z plus two so these are + + align:start position:0% +leave you form Z plus two so these are + + + align:start position:0% +leave you form Z plus two so these are +sort of blowups of the reactions that + + align:start position:0% +sort of blowups of the reactions that + + + align:start position:0% +sort of blowups of the reactions that +are happening uh at the uh cathode and + + align:start position:0% +are happening uh at the uh cathode and + + + align:start position:0% +are happening uh at the uh cathode and +anode and so as this happens you'll see + + align:start position:0% +anode and so as this happens you'll see + + + align:start position:0% +anode and so as this happens you'll see +there'll be a change in the charge so + + align:start position:0% +there'll be a change in the charge so + + + align:start position:0% +there'll be a change in the charge so +here we have uh zinc solid or zinc zero + + align:start position:0% +here we have uh zinc solid or zinc zero + + + align:start position:0% +here we have uh zinc solid or zinc zero +going to zinc plus two so to balance + + align:start position:0% +going to zinc plus two so to balance + + + align:start position:0% +going to zinc plus two so to balance +that charge there's a salt bridge and + + align:start position:0% +that charge there's a salt bridge and + + + align:start position:0% +that charge there's a salt bridge and +you'll have some kind of ion come in to + + align:start position:0% +you'll have some kind of ion come in to + + + align:start position:0% +you'll have some kind of ion come in to +neutralize the charge and here we have + + align:start position:0% +neutralize the charge and here we have + + + align:start position:0% +neutralize the charge and here we have +chloride minus on the other side we're + + align:start position:0% +chloride minus on the other side we're + + + align:start position:0% +chloride minus on the other side we're +going from copper plus two to Copper + + align:start position:0% +going from copper plus two to Copper + + + align:start position:0% +going from copper plus two to Copper +zero and so you'll have a positively + + align:start position:0% +zero and so you'll have a positively + + + align:start position:0% +zero and so you'll have a positively +charged ion coming in to help neutralize + + align:start position:0% +charged ion coming in to help neutralize + + + align:start position:0% +charged ion coming in to help neutralize +that that change in + + align:start position:0% +that that change in + + + align:start position:0% +that that change in +charge so over here something's being + + align:start position:0% +charge so over here something's being + + + align:start position:0% +charge so over here something's being +oxidized at the anode anode is where you + + align:start position:0% +oxidized at the anode anode is where you + + + align:start position:0% +oxidized at the anode anode is where you +have oxidation and something's being + + align:start position:0% +have oxidation and something's being + + + align:start position:0% +have oxidation and something's being +reduced at the cathode cathode is where + + align:start position:0% +reduced at the cathode cathode is where + + + align:start position:0% +reduced at the cathode cathode is where +you have + + align:start position:0% + + + + align:start position:0% + +reduction so we could uh write that cell + + align:start position:0% +reduction so we could uh write that cell + + + align:start position:0% +reduction so we could uh write that cell +in a little bit more simple fact instead + + align:start position:0% +in a little bit more simple fact instead + + + align:start position:0% +in a little bit more simple fact instead +of having that picture we can uh convey + + align:start position:0% +of having that picture we can uh convey + + + align:start position:0% +of having that picture we can uh convey +to others what that picture showed us by + + align:start position:0% +to others what that picture showed us by + + + align:start position:0% +to others what that picture showed us by +this equation + + align:start position:0% +this equation + + + align:start position:0% +this equation +here so we have the two reactions going + + align:start position:0% +here so we have the two reactions going + + + align:start position:0% +here so we have the two reactions going +on we have the zinc reaction which is + + align:start position:0% +on we have the zinc reaction which is + + + align:start position:0% +on we have the zinc reaction which is +shown on one side and that reaction was + + align:start position:0% +shown on one side and that reaction was + + + align:start position:0% +shown on one side and that reaction was +the zinc solid going to the zinc plus + + align:start position:0% +the zinc solid going to the zinc plus + + + align:start position:0% +the zinc solid going to the zinc plus +two and this single line here represents + + align:start position:0% +two and this single line here represents + + + align:start position:0% +two and this single line here represents +a change in Phase a phase boundary so + + align:start position:0% +a change in Phase a phase boundary so + + + align:start position:0% +a change in Phase a phase boundary so +solid going to uh an ion dissolved an + + align:start position:0% +solid going to uh an ion dissolved an + + + align:start position:0% +solid going to uh an ion dissolved an +aquous solution the two lines right here + + align:start position:0% +aquous solution the two lines right here + + + align:start position:0% +aquous solution the two lines right here +represent the salt bridge so this uh + + align:start position:0% +represent the salt bridge so this uh + + + align:start position:0% +represent the salt bridge so this uh +equation then is telling you one + + align:start position:0% +equation then is telling you one + + + align:start position:0% +equation then is telling you one +reaction going on in one Beaker + + align:start position:0% +reaction going on in one Beaker + + + align:start position:0% +reaction going on in one Beaker +separated by the salt bridge this would + + align:start position:0% +separated by the salt bridge this would + + + align:start position:0% +separated by the salt bridge this would +be the reaction going on in the other + + align:start position:0% +be the reaction going on in the other + + + align:start position:0% +be the reaction going on in the other +Beaker and so over here we have copper + + align:start position:0% +Beaker and so over here we have copper + + + align:start position:0% +Beaker and so over here we have copper +plus two aquous with a single line for + + align:start position:0% +plus two aquous with a single line for + + + align:start position:0% +plus two aquous with a single line for +the phase boundary going to Copper solid + + align:start position:0% +the phase boundary going to Copper solid + + + align:start position:0% +the phase boundary going to Copper solid +so if you see see this kind of notation + + align:start position:0% +so if you see see this kind of notation + + + align:start position:0% +so if you see see this kind of notation +you can Envision that electrochemical + + align:start position:0% +you can Envision that electrochemical + + + align:start position:0% +you can Envision that electrochemical +cell with the two beakers the wire and + + align:start position:0% +cell with the two beakers the wire and + + + align:start position:0% +cell with the two beakers the wire and +the salt bridge and you uh can this is + + align:start position:0% +the salt bridge and you uh can this is + + + align:start position:0% +the salt bridge and you uh can this is +reaction going on on one side and the + + align:start position:0% +reaction going on on one side and the + + + align:start position:0% +reaction going on on one side and the +reaction going on on the other + + align:start position:0% + + + + align:start position:0% + +side so as as I + + align:start position:0% +side so as as I + + + align:start position:0% +side so as as I +mentioned in that particular electric + + align:start position:0% +mentioned in that particular electric + + + align:start position:0% +mentioned in that particular electric +chemical cell zinc is being consumed + + align:start position:0% +chemical cell zinc is being consumed + + + align:start position:0% +chemical cell zinc is being consumed +zinc solid is being consumed it's being + + align:start position:0% +zinc solid is being consumed it's being + + + align:start position:0% +zinc solid is being consumed it's being +converted to zinc plus two whereas + + align:start position:0% +converted to zinc plus two whereas + + + align:start position:0% +converted to zinc plus two whereas +copper solid is being deposited onto the + + align:start position:0% +copper solid is being deposited onto the + + + align:start position:0% +copper solid is being deposited onto the +electrode so in that case you have + + align:start position:0% +electrode so in that case you have + + + align:start position:0% +electrode so in that case you have +copper plus two aquous going to Copper + + align:start position:0% +copper plus two aquous going to Copper + + + align:start position:0% +copper plus two aquous going to Copper +solid so that's being + + align:start position:0% +solid so that's being + + + align:start position:0% +solid so that's being +deposited and the amount of zinc that's + + align:start position:0% +deposited and the amount of zinc that's + + + align:start position:0% +deposited and the amount of zinc that's +consumed and the amount of copper that's + + align:start position:0% +consumed and the amount of copper that's + + + align:start position:0% +consumed and the amount of copper that's +deposited is going to be proportional to + + align:start position:0% +deposited is going to be proportional to + + + align:start position:0% +deposited is going to be proportional to +the charge that passes through the + + align:start position:0% +the charge that passes through the + + + align:start position:0% +the charge that passes through the +system or to the electrons that pass + + align:start position:0% +system or to the electrons that pass + + + align:start position:0% +system or to the electrons that pass +through the system and that makes sense + + align:start position:0% +through the system and that makes sense + + + align:start position:0% +through the system and that makes sense +because if you have uh zinc solid going + + align:start position:0% +because if you have uh zinc solid going + + + align:start position:0% +because if you have uh zinc solid going +to zinc plus two you have two electrons + + align:start position:0% +to zinc plus two you have two electrons + + + align:start position:0% +to zinc plus two you have two electrons +formed which would then go through to + + align:start position:0% +formed which would then go through to + + + align:start position:0% +formed which would then go through to +the other side so the amount of charge + + align:start position:0% +the other side so the amount of charge + + + align:start position:0% +the other side so the amount of charge +that's going to go through has to do + + align:start position:0% +that's going to go through has to do + + + align:start position:0% +that's going to go through has to do +with the amount of zinc that's consumed + + align:start position:0% +with the amount of zinc that's consumed + + + align:start position:0% +with the amount of zinc that's consumed +which would also then have to do with + + align:start position:0% +which would also then have to do with + + + align:start position:0% +which would also then have to do with +the amount of copper that's deposited + + align:start position:0% +the amount of copper that's deposited + + + align:start position:0% +the amount of copper that's deposited +when the electrons get to the other side + + align:start position:0% +when the electrons get to the other side + + + align:start position:0% +when the electrons get to the other side +and so this is a law we don't have very + + align:start position:0% +and so this is a law we don't have very + + + align:start position:0% +and so this is a law we don't have very +many laws in chemistry a lot of times we + + align:start position:0% +many laws in chemistry a lot of times we + + + align:start position:0% +many laws in chemistry a lot of times we +have theories uh that help to explain + + align:start position:0% +have theories uh that help to explain + + + align:start position:0% +have theories uh that help to explain +observed uh information chemistry really + + align:start position:0% +observed uh information chemistry really + + + align:start position:0% +observed uh information chemistry really +is an experimental science so we observe + + align:start position:0% +is an experimental science so we observe + + + align:start position:0% +is an experimental science so we observe +a lot of things and then we try to + + align:start position:0% +a lot of things and then we try to + + + align:start position:0% +a lot of things and then we try to +rationalize why they're true they're not + + align:start position:0% +rationalize why they're true they're not + + + align:start position:0% +rationalize why they're true they're not +a whole lot of laws but this is this is + + align:start position:0% +a whole lot of laws but this is this is + + + align:start position:0% +a whole lot of laws but this is this is +one of + + align:start position:0% + + + + align:start position:0% + +them all right so let's just kind of + + align:start position:0% +them all right so let's just kind of + + + align:start position:0% +them all right so let's just kind of +look at little movies of of of this uh + + align:start position:0% +look at little movies of of of this uh + + + align:start position:0% +look at little movies of of of this uh +procedure of what is is happening and + + align:start position:0% +procedure of what is is happening and + + + align:start position:0% +procedure of what is is happening and +here we're going to see + + align:start position:0% +here we're going to see + + + align:start position:0% +here we're going to see +oxidation uh at the anode so we can + + align:start position:0% +oxidation uh at the anode so we can + + + align:start position:0% +oxidation uh at the anode so we can +pretend this is our solid uh electrode + + align:start position:0% +pretend this is our solid uh electrode + + + align:start position:0% +pretend this is our solid uh electrode +here and we have say the zinc and here's + + align:start position:0% +here and we have say the zinc and here's + + + align:start position:0% +here and we have say the zinc and here's +the aquous part so these are water + + align:start position:0% +the aquous part so these are water + + + align:start position:0% +the aquous part so these are water +molecules and you're going to see a + + align:start position:0% +molecules and you're going to see a + + + align:start position:0% +molecules and you're going to see a +electrons leave go up and uh then you're + + align:start position:0% +electrons leave go up and uh then you're + + + align:start position:0% +electrons leave go up and uh then you're +going to have the solid is going to uh + + align:start position:0% +going to have the solid is going to uh + + + align:start position:0% +going to have the solid is going to uh +then be oxidized to in this case zinc + + align:start position:0% +then be oxidized to in this case zinc + + + align:start position:0% +then be oxidized to in this case zinc +plus two and it'll go into solution so + + align:start position:0% +plus two and it'll go into solution so + + + align:start position:0% +plus two and it'll go into solution so +let me just play this for you you can + + align:start position:0% +let me just play this for you you can + + + align:start position:0% +let me just play this for you you can +see you can actually see the electrons + + align:start position:0% +see you can actually see the electrons + + + align:start position:0% +see you can actually see the electrons +leave in this movie which uh is uh + + align:start position:0% +leave in this movie which uh is uh + + + align:start position:0% +leave in this movie which uh is uh +interesting so okay there they go there + + align:start position:0% +interesting so okay there they go there + + + align:start position:0% +interesting so okay there they go there +are the electrons leaving up and you've + + align:start position:0% +are the electrons leaving up and you've + + + align:start position:0% +are the electrons leaving up and you've +you freed up some of the solid and now + + align:start position:0% +you freed up some of the solid and now + + + align:start position:0% +you freed up some of the solid and now +you freed up again so now we have uh + + align:start position:0% +you freed up again so now we have uh + + + align:start position:0% +you freed up again so now we have uh +zinc plus two we had zinc solid but now + + align:start position:0% +zinc plus two we had zinc solid but now + + + align:start position:0% +zinc plus two we had zinc solid but now +uh We've uh consumed some of our + + align:start position:0% +uh We've uh consumed some of our + + + align:start position:0% +uh We've uh consumed some of our +electrode and it's in + + align:start position:0% +electrode and it's in + + + align:start position:0% +electrode and it's in +solution so we can now you know what + + align:start position:0% +solution so we can now you know what + + + align:start position:0% +solution so we can now you know what +you're looking for I'll just play that + + align:start position:0% +you're looking for I'll just play that + + + align:start position:0% +you're looking for I'll just play that +one more time okay the electrons are + + align:start position:0% +one more time okay the electrons are + + + align:start position:0% +one more time okay the electrons are +heading off into the wires and uh you're + + align:start position:0% +heading off into the wires and uh you're + + + align:start position:0% +heading off into the wires and uh you're +consuming your + + align:start position:0% + + + + align:start position:0% + +electrode all right so let's go the + + align:start position:0% +electrode all right so let's go the + + + align:start position:0% +electrode all right so let's go the +other direction the electrodes the + + align:start position:0% +other direction the electrodes the + + + align:start position:0% +other direction the electrodes the +electrons that left and passed through + + align:start position:0% +electrons that left and passed through + + + align:start position:0% +electrons that left and passed through +the w + + align:start position:0% +the w + + + align:start position:0% +the w +are now coming down to the cathode and + + align:start position:0% +are now coming down to the cathode and + + + align:start position:0% +are now coming down to the cathode and +so those electrons can come in and uh + + align:start position:0% +so those electrons can come in and uh + + + align:start position:0% +so those electrons can come in and uh +reduce say copper plus two forming + + align:start position:0% +reduce say copper plus two forming + + + align:start position:0% +reduce say copper plus two forming +copper + + align:start position:0% + + + + align:start position:0% + +solid so we have copper plus two here + + align:start position:0% +solid so we have copper plus two here + + + align:start position:0% +solid so we have copper plus two here +come the electrons here come the + + align:start position:0% +come the electrons here come the + + + align:start position:0% +come the electrons here come the +electrons and so now you've plated those + + align:start position:0% +electrons and so now you've plated those + + + align:start position:0% +electrons and so now you've plated those +two copper plus two ions they become + + align:start position:0% +two copper plus two ions they become + + + align:start position:0% +two copper plus two ions they become +copper solid and and now your cathode + + align:start position:0% +copper solid and and now your cathode + + + align:start position:0% +copper solid and and now your cathode +has expanded you've added uh more metal + + align:start position:0% +has expanded you've added uh more metal + + + align:start position:0% +has expanded you've added uh more metal +onto it it's been deposited or plated + + align:start position:0% +onto it it's been deposited or plated + + + align:start position:0% +onto it it's been deposited or plated +onto this uh + + align:start position:0% +onto this uh + + + align:start position:0% +onto this uh +electrod and again the amounts are going + + align:start position:0% +electrod and again the amounts are going + + + align:start position:0% +electrod and again the amounts are going +to be equal so there's Faraday law would + + align:start position:0% +to be equal so there's Faraday law would + + + align:start position:0% +to be equal so there's Faraday law would +tell you that it's all going to be + + align:start position:0% +tell you that it's all going to be + + + align:start position:0% +tell you that it's all going to be +proportional the amount that's consumed + + align:start position:0% +proportional the amount that's consumed + + + align:start position:0% +proportional the amount that's consumed +the amount that's produced is all going + + align:start position:0% +the amount that's produced is all going + + + align:start position:0% +the amount that's produced is all going +to be equal to the number of electrons + + align:start position:0% +to be equal to the number of electrons + + + align:start position:0% +to be equal to the number of electrons +that pass through the + + align:start position:0% +that pass through the + + + align:start position:0% +that pass through the +system so let me just show you uh one + + align:start position:0% +system so let me just show you uh one + + + align:start position:0% +system so let me just show you uh one +more example of why this could be useful + + align:start position:0% +more example of why this could be useful + + + align:start position:0% +more example of why this could be useful +in terms of the plating um so in this uh + + align:start position:0% +in terms of the plating um so in this uh + + + align:start position:0% +in terms of the plating um so in this uh +little experiment we have a steel spoon + + align:start position:0% +little experiment we have a steel spoon + + + align:start position:0% +little experiment we have a steel spoon +and uh it's going to be the steel spoon + + align:start position:0% +and uh it's going to be the steel spoon + + + align:start position:0% +and uh it's going to be the steel spoon +will will act like an electrode and get + + align:start position:0% +will will act like an electrode and get + + + align:start position:0% +will will act like an electrode and get +plated with + + align:start position:0% + + + + align:start position:0% + +copper so this + + align:start position:0% +copper so this + + + align:start position:0% +copper so this +has this seal spoon will have a thin + + align:start position:0% +has this seal spoon will have a thin + + + align:start position:0% +has this seal spoon will have a thin +coting of copper on there's the copper + + align:start position:0% +coting of copper on there's the copper + + + align:start position:0% +coting of copper on there's the copper +wire cell consists of an copper a + + align:start position:0% +wire cell consists of an copper a + + + align:start position:0% +wire cell consists of an copper a +solution of copper sulfate and as a + + align:start position:0% +solution of copper sulfate and as a + + + align:start position:0% +solution of copper sulfate and as a +cathod a spoon there is no net reaction + + align:start position:0% +cathod a spoon there is no net reaction + + + align:start position:0% +cathod a spoon there is no net reaction +but copper metal is transferred from the + + align:start position:0% +but copper metal is transferred from the + + + align:start position:0% +but copper metal is transferred from the +anod to the + + align:start position:0% + + + + align:start position:0% + +cathode + + align:start position:0% + + + + align:start position:0% + +pretty okay so that's pretty simple so + + align:start position:0% +pretty okay so that's pretty simple so + + + align:start position:0% +pretty okay so that's pretty simple so +then you can see how it can get + + align:start position:0% +then you can see how it can get + + + align:start position:0% +then you can see how it can get +deposited uh on top of this which was + + align:start position:0% +deposited uh on top of this which was + + + align:start position:0% +deposited uh on top of this which was +acting as an electrode in this case all + + align:start position:0% +acting as an electrode in this case all + + + align:start position:0% +acting as an electrode in this case all +right so as you probably figured out you + + align:start position:0% +right so as you probably figured out you + + + align:start position:0% +right so as you probably figured out you +oh + + align:start position:0% + + + + align:start position:0% + +yeah it's you often will have to figure + + align:start position:0% +yeah it's you often will have to figure + + + align:start position:0% +yeah it's you often will have to figure +that kind of thing out in the example + + align:start position:0% +that kind of thing out in the example + + + align:start position:0% +that kind of thing out in the example +that I showed you it was set up to work + + align:start position:0% +that I showed you it was set up to work + + + align:start position:0% +that I showed you it was set up to work +like that um but as we'll we'll talk + + align:start position:0% +like that um but as we'll we'll talk + + + align:start position:0% +like that um but as we'll we'll talk +about it depends if it's going to be a + + align:start position:0% +about it depends if it's going to be a + + + align:start position:0% +about it depends if it's going to be a +spontaneous reaction or non-spontaneous + + align:start position:0% +spontaneous reaction or non-spontaneous + + + align:start position:0% +spontaneous reaction or non-spontaneous +reaction so if you have a a cell where + + align:start position:0% +reaction so if you have a a cell where + + + align:start position:0% +reaction so if you have a a cell where +it's a spontaneous reaction you can + + align:start position:0% +it's a spontaneous reaction you can + + + align:start position:0% +it's a spontaneous reaction you can +figure out which is going to be it which + + align:start position:0% +figure out which is going to be it which + + + align:start position:0% +figure out which is going to be it which +reaction will occur at the cathode and + + align:start position:0% +reaction will occur at the cathode and + + + align:start position:0% +reaction will occur at the cathode and +which will occur at the anode there's + + align:start position:0% +which will occur at the anode there's + + + align:start position:0% +which will occur at the anode there's +only one one way you can put those thing + + align:start position:0% +only one one way you can put those thing + + + align:start position:0% +only one one way you can put those thing +if you have particular ingredients for + + align:start position:0% +if you have particular ingredients for + + + align:start position:0% +if you have particular ingredients for +it to be spontaneous and so we'll + + align:start position:0% +it to be spontaneous and so we'll + + + align:start position:0% +it to be spontaneous and so we'll +actually talk about that at the end of + + align:start position:0% +actually talk about that at the end of + + + align:start position:0% +actually talk about that at the end of +of the lecture but in that particular + + align:start position:0% +of the lecture but in that particular + + + align:start position:0% +of the lecture but in that particular +case it was just you know stated as you + + align:start position:0% +case it was just you know stated as you + + + align:start position:0% +case it was just you know stated as you +know this is the reaction happening here + + align:start position:0% +know this is the reaction happening here + + + align:start position:0% +know this is the reaction happening here +and here but which will go which place + + align:start position:0% +and here but which will go which place + + + align:start position:0% +and here but which will go which place +will depend on whether you want it to be + + align:start position:0% +will depend on whether you want it to be + + + align:start position:0% +will depend on whether you want it to be +as spontaneous or nonspontaneous I + + align:start position:0% +as spontaneous or nonspontaneous I + + + align:start position:0% +as spontaneous or nonspontaneous I +that's a good question and we'll + + align:start position:0% +that's a good question and we'll + + + align:start position:0% +that's a good question and we'll +definitely come to that so uh in terms + + align:start position:0% +definitely come to that so uh in terms + + + align:start position:0% +definitely come to that so uh in terms +of uh Faraday's law it's proportional + + align:start position:0% +of uh Faraday's law it's proportional + + + align:start position:0% +of uh Faraday's law it's proportional +and that means you can do calculations + + align:start position:0% +and that means you can do calculations + + + align:start position:0% +and that means you can do calculations +so one could figure out how much zinc + + align:start position:0% +so one could figure out how much zinc + + + align:start position:0% +so one could figure out how much zinc +would get consumed or how much copper + + align:start position:0% +would get consumed or how much copper + + + align:start position:0% +would get consumed or how much copper +would get deposited if you had a + + align:start position:0% +would get deposited if you had a + + + align:start position:0% +would get deposited if you had a +particular current flowing for a + + align:start position:0% +particular current flowing for a + + + align:start position:0% +particular current flowing for a +particular amount of time and uh these + + align:start position:0% +particular amount of time and uh these + + + align:start position:0% +particular amount of time and uh these +are actually uh fairly fairly simple + + align:start position:0% +are actually uh fairly fairly simple + + + align:start position:0% +are actually uh fairly fairly simple +calculations to do we'll just go through + + align:start position:0% +calculations to do we'll just go through + + + align:start position:0% +calculations to do we'll just go through +one of + + align:start position:0% +one of + + + align:start position:0% +one of +them so um the first step would be to + + align:start position:0% +them so um the first step would be to + + + align:start position:0% +them so um the first step would be to +figure out how much charge went through + + align:start position:0% +figure out how much charge went through + + + align:start position:0% +figure out how much charge went through +the system so we have q magnitude of of + + align:start position:0% +the system so we have q magnitude of of + + + align:start position:0% +the system so we have q magnitude of of +charge in kums which uh unit is C uh is + + align:start position:0% +charge in kums which uh unit is C uh is + + + align:start position:0% +charge in kums which uh unit is C uh is +going to be equal to the current and + + align:start position:0% +going to be equal to the current and + + + align:start position:0% +going to be equal to the current and +that's in ampers or a and uh here is a + + align:start position:0% +that's in ampers or a and uh here is a + + + align:start position:0% +that's in ampers or a and uh here is a +useful conversion for you to remember + + align:start position:0% +useful conversion for you to remember + + + align:start position:0% +useful conversion for you to remember +and this will be given to you on on a + + align:start position:0% +and this will be given to you on on a + + + align:start position:0% +and this will be given to you on on a +test uh times the amount of time so how + + align:start position:0% +test uh times the amount of time so how + + + align:start position:0% +test uh times the amount of time so how +much current times time will tell you + + align:start position:0% +much current times time will tell you + + + align:start position:0% +much current times time will tell you +the uh the magnitude of the charge so + + align:start position:0% +the uh the magnitude of the charge so + + + align:start position:0% +the uh the magnitude of the charge so +that's that's pretty simple and that + + align:start position:0% +that's that's pretty simple and that + + + align:start position:0% +that's that's pretty simple and that +equation would be given to you as well + + align:start position:0% +equation would be given to you as well + + + align:start position:0% +equation would be given to you as well +so uh we have uh we're told that we had + + align:start position:0% +so uh we have uh we're told that we had + + + align:start position:0% +so uh we have uh we're told that we had +one uh one amp uh for one hour and we've + + align:start position:0% +one uh one amp uh for one hour and we've + + + align:start position:0% +one uh one amp uh for one hour and we've +converted it to seconds so you can get + + align:start position:0% +converted it to seconds so you can get + + + align:start position:0% +converted it to seconds so you can get +the right the right units we can find + + align:start position:0% +the right the right units we can find + + + align:start position:0% +the right the right units we can find +out the magnitude of the charge then in + + align:start position:0% +out the magnitude of the charge then in + + + align:start position:0% +out the magnitude of the charge then in +kums because these units multiplied + + align:start position:0% +kums because these units multiplied + + + align:start position:0% +kums because these units multiplied +together will get you kums + + align:start position:0% +together will get you kums + + + align:start position:0% +together will get you kums +so then uh step two is to figure out how + + align:start position:0% +so then uh step two is to figure out how + + + align:start position:0% +so then uh step two is to figure out how +many moles of electron that charge is + + align:start position:0% +many moles of electron that charge is + + + align:start position:0% +many moles of electron that charge is +equal to and uh we have Faraday constant + + align:start position:0% +equal to and uh we have Faraday constant + + + align:start position:0% +equal to and uh we have Faraday constant +uh which will also be provided to you + + align:start position:0% +uh which will also be provided to you + + + align:start position:0% +uh which will also be provided to you +and its units you can um using the + + align:start position:0% +and its units you can um using the + + + align:start position:0% +and its units you can um using the +conversion Kum per mole and it also is + + align:start position:0% +conversion Kum per mole and it also is + + + align:start position:0% +conversion Kum per mole and it also is +equal to one Faraday which is usually + + align:start position:0% +equal to one Faraday which is usually + + + align:start position:0% +equal to one Faraday which is usually +kind of a squiggly kind of f symbol here + + align:start position:0% +kind of a squiggly kind of f symbol here + + + align:start position:0% +kind of a squiggly kind of f symbol here +and so then if we go through we use + + align:start position:0% +and so then if we go through we use + + + align:start position:0% +and so then if we go through we use +Faraday constant we can figure out that + + align:start position:0% +Faraday constant we can figure out that + + + align:start position:0% +Faraday constant we can figure out that +that number of kums uh convert to moles + + align:start position:0% +that number of kums uh convert to moles + + + align:start position:0% +that number of kums uh convert to moles +and so you would get + + align:start position:0% +and so you would get + + + align:start position:0% +and so you would get +0.373 moles of electrons so this is just + + align:start position:0% +0.373 moles of electrons so this is just + + + align:start position:0% +0.373 moles of electrons so this is just +a conversion using Faraday + + align:start position:0% +a conversion using Faraday + + + align:start position:0% +a conversion using Faraday +constant and then we have to figure out + + align:start position:0% +constant and then we have to figure out + + + align:start position:0% +constant and then we have to figure out +how many moles of the particular element + + align:start position:0% +how many moles of the particular element + + + align:start position:0% +how many moles of the particular element +zinc in this case or copper are + + align:start position:0% +zinc in this case or copper are + + + align:start position:0% +zinc in this case or copper are +deposited and convert to grams so we + + align:start position:0% +deposited and convert to grams so we + + + align:start position:0% +deposited and convert to grams so we +know now how many electrons went through + + align:start position:0% +know now how many electrons went through + + + align:start position:0% +know now how many electrons went through +our our system and so now we just need + + align:start position:0% +our our system and so now we just need + + + align:start position:0% +our our system and so now we just need +to figure out for every one mole of zinc + + align:start position:0% +to figure out for every one mole of zinc + + + align:start position:0% +to figure out for every one mole of zinc +consumed how many moles of electrons + + align:start position:0% +consumed how many moles of electrons + + + align:start position:0% +consumed how many moles of electrons +would have left and in the particular + + align:start position:0% +would have left and in the particular + + + align:start position:0% +would have left and in the particular +example we had what would it be how many + + align:start position:0% +example we had what would it be how many + + + align:start position:0% +example we had what would it be how many +electrons two is we went from zinc to + + align:start position:0% +electrons two is we went from zinc to + + + align:start position:0% +electrons two is we went from zinc to +zinc plus two so we're talking about two + + align:start position:0% +zinc plus two so we're talking about two + + + align:start position:0% +zinc plus two so we're talking about two +electrons for every mole of + + align:start position:0% + + + + align:start position:0% + +zinc and then we can calculate grams of + + align:start position:0% +zinc and then we can calculate grams of + + + align:start position:0% +zinc and then we can calculate grams of +per + + align:start position:0% +per + + + align:start position:0% +per +uh we can CC we can calculate moles and + + align:start position:0% +uh we can CC we can calculate moles and + + + align:start position:0% +uh we can CC we can calculate moles and +convert to grams using the molecular + + align:start position:0% +convert to grams using the molecular + + + align:start position:0% +convert to grams using the molecular +mass of zinc which we can look up so we + + align:start position:0% +mass of zinc which we can look up so we + + + align:start position:0% +mass of zinc which we can look up so we +get 1.2 grams uh are going to be + + align:start position:0% +get 1.2 grams uh are going to be + + + align:start position:0% +get 1.2 grams uh are going to be +consumed at that particular time with + + align:start position:0% +consumed at that particular time with + + + align:start position:0% +consumed at that particular time with +that kind of current passing through the + + align:start position:0% +that kind of current passing through the + + + align:start position:0% +that kind of current passing through the +system we can do the same thing with + + align:start position:0% +system we can do the same thing with + + + align:start position:0% +system we can do the same thing with +copper so we have the same number of + + align:start position:0% +copper so we have the same number of + + + align:start position:0% +copper so we have the same number of +moles of electrons that are going + + align:start position:0% +moles of electrons that are going + + + align:start position:0% +moles of electrons that are going +through our system and now we just need + + align:start position:0% +through our system and now we just need + + + align:start position:0% +through our system and now we just need +to know for every one mole of copper + + align:start position:0% +to know for every one mole of copper + + + align:start position:0% +to know for every one mole of copper +deposited how many electrons are + + align:start position:0% +deposited how many electrons are + + + align:start position:0% +deposited how many electrons are +required and that + + align:start position:0% +required and that + + + align:start position:0% +required and that +is two again because we were taking + + align:start position:0% +is two again because we were taking + + + align:start position:0% +is two again because we were taking +copper plus two to Copper solid so we + + align:start position:0% +copper plus two to Copper solid so we + + + align:start position:0% +copper plus two to Copper solid so we +need two electrons for every one uh mole + + align:start position:0% +need two electrons for every one uh mole + + + align:start position:0% +need two electrons for every one uh mole +of copper that gets + + align:start position:0% +of copper that gets + + + align:start position:0% +of copper that gets +deposited and then we can use uh the + + align:start position:0% +deposited and then we can use uh the + + + align:start position:0% +deposited and then we can use uh the +molecular mass to find out the number of + + align:start position:0% +molecular mass to find out the number of + + + align:start position:0% +molecular mass to find out the number of +grams and since these weigh a very + + align:start position:0% +grams and since these weigh a very + + + align:start position:0% +grams and since these weigh a very +similar amount it's about the same uh + + align:start position:0% +similar amount it's about the same uh + + + align:start position:0% +similar amount it's about the same uh +the same number of grams um if there was + + align:start position:0% +the same number of grams um if there was + + + align:start position:0% +the same number of grams um if there was +a very difference in in molecular mass + + align:start position:0% +a very difference in in molecular mass + + + align:start position:0% +a very difference in in molecular mass +then that wouldn't be true these are not + + align:start position:0% +then that wouldn't be true these are not + + + align:start position:0% +then that wouldn't be true these are not +always near each other all right so + + align:start position:0% +always near each other all right so + + + align:start position:0% +always near each other all right so +that's just how you do one of these + + align:start position:0% +that's just how you do one of these + + + align:start position:0% +that's just how you do one of these +problems they're really pretty + + align:start position:0% + + + + align:start position:0% + +simple and there are there are some of + + align:start position:0% +simple and there are there are some of + + + align:start position:0% +simple and there are there are some of +those at the end actually of the problem + + align:start position:0% +those at the end actually of the problem + + + align:start position:0% +those at the end actually of the problem +set so the problem set the book has + + align:start position:0% +set so the problem set the book has + + + align:start position:0% +set so the problem set the book has +things in a sort of different order so + + align:start position:0% +things in a sort of different order so + + + align:start position:0% +things in a sort of different order so +uh you'll be able to do the first part + + align:start position:0% +uh you'll be able to do the first part + + + align:start position:0% +uh you'll be able to do the first part +of the problem set and the end of the + + align:start position:0% +of the problem set and the end of the + + + align:start position:0% +of the problem set and the end of the +problem set at this point Point all + + align:start position:0% +problem set at this point Point all + + + align:start position:0% +problem set at this point Point all +right so let me just introduce you to a + + align:start position:0% +right so let me just introduce you to a + + + align:start position:0% +right so let me just introduce you to a +couple of different kinds of + + align:start position:0% +couple of different kinds of + + + align:start position:0% +couple of different kinds of +electrochemical cells so up until this + + align:start position:0% +electrochemical cells so up until this + + + align:start position:0% +electrochemical cells so up until this +point we've only talked about + + align:start position:0% +point we've only talked about + + + align:start position:0% +point we've only talked about +electrochemical cells where something + + align:start position:0% +electrochemical cells where something + + + align:start position:0% +electrochemical cells where something +was deposited or consumed but you can + + align:start position:0% +was deposited or consumed but you can + + + align:start position:0% +was deposited or consumed but you can +use electrodes that are inert I.E they + + align:start position:0% +use electrodes that are inert I.E they + + + align:start position:0% +use electrodes that are inert I.E they +don't get consumed in the reaction or um + + align:start position:0% +don't get consumed in the reaction or um + + + align:start position:0% +don't get consumed in the reaction or um +and an example of that is platinum + + align:start position:0% +and an example of that is platinum + + + align:start position:0% +and an example of that is platinum +electrode so uh as it says they're not + + align:start position:0% +electrode so uh as it says they're not + + + align:start position:0% +electrode so uh as it says they're not +always consumed or produced you can have + + align:start position:0% +always consumed or produced you can have + + + align:start position:0% +always consumed or produced you can have +an inert electrode such as a platinum so + + align:start position:0% +an inert electrode such as a platinum so + + + align:start position:0% +an inert electrode such as a platinum so +in this case we have the Platinum + + align:start position:0% +in this case we have the Platinum + + + align:start position:0% +in this case we have the Platinum +electrode to transfer the electrons + + align:start position:0% +electrode to transfer the electrons + + + align:start position:0% +electrode to transfer the electrons +around but the reaction that's going on + + align:start position:0% +around but the reaction that's going on + + + align:start position:0% +around but the reaction that's going on +is all in + + align:start position:0% + + + + align:start position:0% + +solution so this side would be the same + + align:start position:0% +solution so this side would be the same + + + align:start position:0% +solution so this side would be the same +uh this is the the cathode or the + + align:start position:0% +uh this is the the cathode or the + + + align:start position:0% +uh this is the the cathode or the +reduction reaction so we have again the + + align:start position:0% +reduction reaction so we have again the + + + align:start position:0% +reduction reaction so we have again the +copper plus two uh two electrons will + + align:start position:0% +copper plus two uh two electrons will + + + align:start position:0% +copper plus two uh two electrons will +come through the system and plate more + + align:start position:0% +come through the system and plate more + + + align:start position:0% +come through the system and plate more +copper solid on um on to the electrode + + align:start position:0% +copper solid on um on to the electrode + + + align:start position:0% +copper solid on um on to the electrode +here but on the other side the anode + + align:start position:0% +here but on the other side the anode + + + align:start position:0% +here but on the other side the anode +where you have the oxidation the + + align:start position:0% +where you have the oxidation the + + + align:start position:0% +where you have the oxidation the +oxidation reaction is happening all in + + align:start position:0% +oxidation reaction is happening all in + + + align:start position:0% +oxidation reaction is happening all in +solution so the Platinum electrode is + + align:start position:0% +solution so the Platinum electrode is + + + align:start position:0% +solution so the Platinum electrode is +not involved in that so in this case we + + align:start position:0% +not involved in that so in this case we + + + align:start position:0% +not involved in that so in this case we +have chromium plus two going to chromium + + align:start position:0% +have chromium plus two going to chromium + + + align:start position:0% +have chromium plus two going to chromium ++ three with one electron so that is + + align:start position:0% ++ three with one electron so that is + + + align:start position:0% ++ three with one electron so that is +another type of electrochemical cell and + + align:start position:0% +another type of electrochemical cell and + + + align:start position:0% +another type of electrochemical cell and +so we can uh we can write this in look + + align:start position:0% +so we can uh we can write this in look + + + align:start position:0% +so we can uh we can write this in look +at the + + align:start position:0% +at the + + + align:start position:0% +at the +uh look at the notation for this kind of + + align:start position:0% +uh look at the notation for this kind of + + + align:start position:0% +uh look at the notation for this kind of +cell so in in this case you'd put the + + align:start position:0% +cell so in in this case you'd put the + + + align:start position:0% +cell so in in this case you'd put the +Platinum solid in the equation on this + + align:start position:0% +Platinum solid in the equation on this + + + align:start position:0% +Platinum solid in the equation on this +side we have a single line meaning + + align:start position:0% +side we have a single line meaning + + + align:start position:0% +side we have a single line meaning +there's a phase boundary so we're going + + align:start position:0% +there's a phase boundary so we're going + + + align:start position:0% +there's a phase boundary so we're going +from solid uh to to Something in + + align:start position:0% +from solid uh to to Something in + + + align:start position:0% +from solid uh to to Something in +solution and now here is our reaction + + align:start position:0% +solution and now here is our reaction + + + align:start position:0% +solution and now here is our reaction +that happens at the anode and it has a + + align:start position:0% +that happens at the anode and it has a + + + align:start position:0% +that happens at the anode and it has a +comma in between so this indicates that + + align:start position:0% +comma in between so this indicates that + + + align:start position:0% +comma in between so this indicates that +chromium plus two is going to chromium + + align:start position:0% +chromium plus two is going to chromium + + + align:start position:0% +chromium plus two is going to chromium +plus three but there's no phase boundary + + align:start position:0% +plus three but there's no phase boundary + + + align:start position:0% +plus three but there's no phase boundary +between those so there's a comma uh then + + align:start position:0% +between those so there's a comma uh then + + + align:start position:0% +between those so there's a comma uh then +on the other side the two lines + + align:start position:0% +on the other side the two lines + + + align:start position:0% +on the other side the two lines +indicating the salt bridge and then on + + align:start position:0% +indicating the salt bridge and then on + + + align:start position:0% +indicating the salt bridge and then on +the other side we have the copper plus + + align:start position:0% +the other side we have the copper plus + + + align:start position:0% +the other side we have the copper plus +two aquous the line that does indicate + + align:start position:0% +two aquous the line that does indicate + + + align:start position:0% +two aquous the line that does indicate +there's a phase boundary uh going to + + align:start position:0% +there's a phase boundary uh going to + + + align:start position:0% +there's a phase boundary uh going to +Copper so this would be for our anode + + align:start position:0% +Copper so this would be for our anode + + + align:start position:0% +Copper so this would be for our anode +reaction of chromium going to chromium + + align:start position:0% +reaction of chromium going to chromium + + + align:start position:0% +reaction of chromium going to chromium +plus three and one electrode and our + + align:start position:0% +plus three and one electrode and our + + + align:start position:0% +plus three and one electrode and our +cathode reaction copper plus 2 plus two + + align:start position:0% +cathode reaction copper plus 2 plus two + + + align:start position:0% +cathode reaction copper plus 2 plus two +electrons going to Copper solid so + + align:start position:0% +electrons going to Copper solid so + + + align:start position:0% +electrons going to Copper solid so +you'll see this kind of notation in + + align:start position:0% +you'll see this kind of notation in + + + align:start position:0% +you'll see this kind of notation in +these problems as + + align:start position:0% +these problems as + + + align:start position:0% +these problems as +well + + align:start position:0% + + + + align:start position:0% + +all right another example of an inert El + + align:start position:0% +all right another example of an inert El + + + align:start position:0% +all right another example of an inert El +electrode um that sometimes use the + + align:start position:0% +electrode um that sometimes use the + + + align:start position:0% +electrode um that sometimes use the +hydrogen + + align:start position:0% +hydrogen + + + align:start position:0% +hydrogen +electrode + + align:start position:0% +electrode + + + align:start position:0% +electrode +um so often you will see this and + + align:start position:0% +um so often you will see this and + + + align:start position:0% +um so often you will see this and +actually in the back of of your book you + + align:start position:0% +actually in the back of of your book you + + + align:start position:0% +actually in the back of of your book you +will see this as well standard hydrogen + + align:start position:0% +will see this as well standard hydrogen + + + align:start position:0% +will see this as well standard hydrogen +electrode abbreviated she so often + + align:start position:0% +electrode abbreviated she so often + + + align:start position:0% +electrode abbreviated she so often +you'll see in papers or in your book + + align:start position:0% +you'll see in papers or in your book + + + align:start position:0% +you'll see in papers or in your book +that they often need to mention how + + align:start position:0% +that they often need to mention how + + + align:start position:0% +that they often need to mention how +these Redux potentials were measured and + + align:start position:0% +these Redux potentials were measured and + + + align:start position:0% +these Redux potentials were measured and +it's often said it's measured against + + align:start position:0% +it's often said it's measured against + + + align:start position:0% +it's often said it's measured against +she and that's what that stands for the + + align:start position:0% +she and that's what that stands for the + + + align:start position:0% +she and that's what that stands for the +standard hydrogen electrode so you can + + align:start position:0% +standard hydrogen electrode so you can + + + align:start position:0% +standard hydrogen electrode so you can +have the hydrogen electrode on either + + align:start position:0% +have the hydrogen electrode on either + + + align:start position:0% +have the hydrogen electrode on either +side at the anode or at the cathode so + + align:start position:0% +side at the anode or at the cathode so + + + align:start position:0% +side at the anode or at the cathode so +uh over here would be an example when + + align:start position:0% +uh over here would be an example when + + + align:start position:0% +uh over here would be an example when +it's at the at the cathode and in this + + align:start position:0% +it's at the at the cathode and in this + + + align:start position:0% +it's at the at the cathode and in this +case H+ is being reduced and so we have + + align:start position:0% +case H+ is being reduced and so we have + + + align:start position:0% +case H+ is being reduced and so we have +H+ and that's aquous the line for the + + align:start position:0% +H+ and that's aquous the line for the + + + align:start position:0% +H+ and that's aquous the line for the +phase boundary to H2 gas and then you + + align:start position:0% +phase boundary to H2 gas and then you + + + align:start position:0% +phase boundary to H2 gas and then you +have also a phase boundary to the + + align:start position:0% +have also a phase boundary to the + + + align:start position:0% +have also a phase boundary to the +Platinum solid so this is a combining + + align:start position:0% +Platinum solid so this is a combining + + + align:start position:0% +Platinum solid so this is a combining +the platinum and and the + + align:start position:0% +the platinum and and the + + + align:start position:0% +the platinum and and the +hydrogen and uh then on the other side + + align:start position:0% +hydrogen and uh then on the other side + + + align:start position:0% +hydrogen and uh then on the other side +if you had uh it reacting as an anode in + + align:start position:0% +if you had uh it reacting as an anode in + + + align:start position:0% +if you had uh it reacting as an anode in +this case H2 is getting oxidized so you + + align:start position:0% +this case H2 is getting oxidized so you + + + align:start position:0% +this case H2 is getting oxidized so you +have the Platinum solid phase boundary + + align:start position:0% +have the Platinum solid phase boundary + + + align:start position:0% +have the Platinum solid phase boundary +uh hydrogen gas so that would be uh + + align:start position:0% +uh hydrogen gas so that would be uh + + + align:start position:0% +uh hydrogen gas so that would be uh +oxidation state zero phase boundary uh + + align:start position:0% +oxidation state zero phase boundary uh + + + align:start position:0% +oxidation state zero phase boundary uh +to + + align:start position:0% +to + + + align:start position:0% +to +H+ aquous so you can use this sort of + + align:start position:0% +H+ aquous so you can use this sort of + + + align:start position:0% +H+ aquous so you can use this sort of +combination of the platinum and the + + align:start position:0% +combination of the platinum and the + + + align:start position:0% +combination of the platinum and the +hydrogen electrodes as either cathodes + + align:start position:0% +hydrogen electrodes as either cathodes + + + align:start position:0% +hydrogen electrodes as either cathodes +or + + align:start position:0% +or + + + align:start position:0% +or +anodes and so just one example of what + + align:start position:0% +anodes and so just one example of what + + + align:start position:0% +anodes and so just one example of what +this sort of thing would look like so + + align:start position:0% +this sort of thing would look like so + + + align:start position:0% +this sort of thing would look like so +here we have an electrochemical cell now + + align:start position:0% +here we have an electrochemical cell now + + + align:start position:0% +here we have an electrochemical cell now +on this side we just have the the zinc + + align:start position:0% +on this side we just have the the zinc + + + align:start position:0% +on this side we just have the the zinc +electrode which we mentioned in the + + align:start position:0% +electrode which we mentioned in the + + + align:start position:0% +electrode which we mentioned in the +beginning zinc solid and then that would + + align:start position:0% +beginning zinc solid and then that would + + + align:start position:0% +beginning zinc solid and then that would +be zinc plus two in solution we have + + align:start position:0% +be zinc plus two in solution we have + + + align:start position:0% +be zinc plus two in solution we have +wire our salt bridge and in the other + + align:start position:0% +wire our salt bridge and in the other + + + align:start position:0% +wire our salt bridge and in the other +Beaker on the other side we have H some + + align:start position:0% +Beaker on the other side we have H some + + + align:start position:0% +Beaker on the other side we have H some +glass tubing where you would have + + align:start position:0% +glass tubing where you would have + + + align:start position:0% +glass tubing where you would have +hydrogen gas uh in going through into + + align:start position:0% +hydrogen gas uh in going through into + + + align:start position:0% +hydrogen gas uh in going through into +the system um you also have through that + + align:start position:0% +the system um you also have through that + + + align:start position:0% +the system um you also have through that +uh the Platinum uh electrode Platinum + + align:start position:0% +uh the Platinum uh electrode Platinum + + + align:start position:0% +uh the Platinum uh electrode Platinum +solid and you have HCL in your Beaker so + + align:start position:0% +solid and you have HCL in your Beaker so + + + align:start position:0% +solid and you have HCL in your Beaker so +that would be + + align:start position:0% +that would be + + + align:start position:0% +that would be +H+ uh in your + + align:start position:0% +H+ uh in your + + + align:start position:0% +H+ uh in your +Beaker so here is the cathode reaction + + align:start position:0% +Beaker so here is the cathode reaction + + + align:start position:0% +Beaker so here is the cathode reaction +so you would be going from h H+ to h0 + + align:start position:0% +so you would be going from h H+ to h0 + + + align:start position:0% +so you would be going from h H+ to h0 +gas and so as you have the reaction over + + align:start position:0% +gas and so as you have the reaction over + + + align:start position:0% +gas and so as you have the reaction over +here um zinc solid to zinc plus2 + + align:start position:0% +here um zinc solid to zinc plus2 + + + align:start position:0% +here um zinc solid to zinc plus2 +electrons would come along and uh they + + align:start position:0% +electrons would come along and uh they + + + align:start position:0% +electrons would come along and uh they +would convert H+ to H H2 and the + + align:start position:0% +would convert H+ to H H2 and the + + + align:start position:0% +would convert H+ to H H2 and the +electrode here is the inert Platinum + + align:start position:0% +electrode here is the inert Platinum + + + align:start position:0% +electrode here is the inert Platinum +electrode and so here's my attempt to + + align:start position:0% +electrode and so here's my attempt to + + + align:start position:0% +electrode and so here's my attempt to +draw little H2 uh gas bubbles going on + + align:start position:0% +draw little H2 uh gas bubbles going on + + + align:start position:0% +draw little H2 uh gas bubbles going on +so this is another type of electrode + + align:start position:0% +so this is another type of electrode + + + align:start position:0% +so this is another type of electrode +that you should know the the uh notation + + align:start position:0% +that you should know the the uh notation + + + align:start position:0% +that you should know the the uh notation +for it doesn't really change how you do + + align:start position:0% +for it doesn't really change how you do + + + align:start position:0% +for it doesn't really change how you do +problems particularly but it's important + + align:start position:0% +problems particularly but it's important + + + align:start position:0% +problems particularly but it's important +to know what it stands for and again + + align:start position:0% +to know what it stands for and again + + + align:start position:0% +to know what it stands for and again +this is on the other side we've already + + align:start position:0% +this is on the other side we've already + + + align:start position:0% +this is on the other side we've already +talked about about that kind of + + align:start position:0% + + + + align:start position:0% + +anode all right so this is of course + + align:start position:0% +anode all right so this is of course + + + align:start position:0% +anode all right so this is of course +always things that things that I really + + align:start position:0% +always things that things that I really + + + align:start position:0% +always things that things that I really +like to do because what I like to do is + + align:start position:0% +like to do because what I like to do is + + + align:start position:0% +like to do because what I like to do is +to go back to something you've already + + align:start position:0% +to go back to something you've already + + + align:start position:0% +to go back to something you've already +learned and make connections between + + align:start position:0% +learned and make connections between + + + align:start position:0% +learned and make connections between +different units of fresh freshman + + align:start position:0% +different units of fresh freshman + + + align:start position:0% +different units of fresh freshman +chemistry so we're back to Delta + + align:start position:0% + + + + align:start position:0% + +G so + + align:start position:0% +G so + + + align:start position:0% +G so +um we're going to now talk about cell + + align:start position:0% +um we're going to now talk about cell + + + align:start position:0% +um we're going to now talk about cell +potential and this is abbreviated Delta + + align:start position:0% +potential and this is abbreviated Delta + + + align:start position:0% +potential and this is abbreviated Delta +e cell potential is often called cell + + align:start position:0% +e cell potential is often called cell + + + align:start position:0% +e cell potential is often called cell +voltage and it's also called the + + align:start position:0% +voltage and it's also called the + + + align:start position:0% +voltage and it's also called the +electron motive force or EMF so you'll + + align:start position:0% +electron motive force or EMF so you'll + + + align:start position:0% +electron motive force or EMF so you'll +see all of those different words and + + align:start position:0% +see all of those different words and + + + align:start position:0% +see all of those different words and +they all sort of stand they stand for + + align:start position:0% +they all sort of stand they stand for + + + align:start position:0% +they all sort of stand they stand for +the same thing this Del Del to e + + align:start position:0% +the same thing this Del Del to e + + + align:start position:0% +the same thing this Del Del to e +term and uh the connection with free + + align:start position:0% +term and uh the connection with free + + + align:start position:0% +term and uh the connection with free +energy so when the electrons + + align:start position:0% +energy so when the electrons + + + align:start position:0% +energy so when the electrons +flow that creates a potential difference + + align:start position:0% +flow that creates a potential difference + + + align:start position:0% +flow that creates a potential difference +a Delta e between the electrodes in the + + align:start position:0% +a Delta e between the electrodes in the + + + align:start position:0% +a Delta e between the electrodes in the +circuit and so the overall free energy + + align:start position:0% +circuit and so the overall free energy + + + align:start position:0% +circuit and so the overall free energy +of the cell is related to this cell + + align:start position:0% +of the cell is related to this cell + + + align:start position:0% +of the cell is related to this cell +potential by the following equation so + + align:start position:0% +potential by the following equation so + + + align:start position:0% +potential by the following equation so +we have Delta G for that particular + + align:start position:0% +we have Delta G for that particular + + + align:start position:0% +we have Delta G for that particular +electrochemical cell is going to be + + align:start position:0% +electrochemical cell is going to be + + + align:start position:0% +electrochemical cell is going to be +equal to to + + align:start position:0% +equal to to + + + align:start position:0% +equal to to +minus n which is the number of electrons + + align:start position:0% +minus n which is the number of electrons + + + align:start position:0% +minus n which is the number of electrons +that are going through the system times + + align:start position:0% +that are going through the system times + + + align:start position:0% +that are going through the system times +Faraday's constant which we talked about + + align:start position:0% +Faraday's constant which we talked about + + + align:start position:0% +Faraday's constant which we talked about +a few minutes ago and Delta e the cell + + align:start position:0% +a few minutes ago and Delta e the cell + + + align:start position:0% +a few minutes ago and Delta e the cell +potential uh for that particular cell so + + align:start position:0% +potential uh for that particular cell so + + + align:start position:0% +potential uh for that particular cell so +there's a nice connection between these + + align:start position:0% +there's a nice connection between these + + + align:start position:0% +there's a nice connection between these +two and that'll be really useful in + + align:start position:0% +two and that'll be really useful in + + + align:start position:0% +two and that'll be really useful in +doing these + + align:start position:0% +doing these + + + align:start position:0% +doing these +problems so um we can also talk about + + align:start position:0% +problems so um we can also talk about + + + align:start position:0% +problems so um we can also talk about +standard States here and the same + + align:start position:0% +standard States here and the same + + + align:start position:0% +standard States here and the same +equation applies whether you're talking + + align:start position:0% +equation applies whether you're talking + + + align:start position:0% +equation applies whether you're talking +about Delta G at any particular time and + + align:start position:0% +about Delta G at any particular time and + + + align:start position:0% +about Delta G at any particular time and +Delta e at any particular time or you're + + align:start position:0% +Delta e at any particular time or you're + + + align:start position:0% +Delta e at any particular time or you're +talking about the Delta G and the Delta + + align:start position:0% +talking about the Delta G and the Delta + + + align:start position:0% +talking about the Delta G and the Delta +e in their standard States so again uh + + align:start position:0% +e in their standard States so again uh + + + align:start position:0% +e in their standard States so again uh +this means the same thing that it has + + align:start position:0% +this means the same thing that it has + + + align:start position:0% +this means the same thing that it has +before uh Delta e KN the knot means that + + align:start position:0% +before uh Delta e KN the knot means that + + + align:start position:0% +before uh Delta e KN the knot means that +you're you're at the standard States and + + align:start position:0% +you're you're at the standard States and + + + align:start position:0% +you're you're at the standard States and +uh Delta G of course a Delta G not is + + align:start position:0% +uh Delta G of course a Delta G not is + + + align:start position:0% +uh Delta G of course a Delta G not is +also Delta G in the standard State and + + align:start position:0% +also Delta G in the standard State and + + + align:start position:0% +also Delta G in the standard State and +uh units of course are important when + + align:start position:0% +uh units of course are important when + + + align:start position:0% +uh units of course are important when +you're talking about without any kind of + + align:start position:0% +you're talking about without any kind of + + + align:start position:0% +you're talking about without any kind of +Delta e or cell potential you're talking + + align:start position:0% +Delta e or cell potential you're talking + + + align:start position:0% +Delta e or cell potential you're talking +about things in volts as the + + align:start position:0% +about things in volts as the + + + align:start position:0% +about things in volts as the +units all right so now what those + + align:start position:0% +units all right so now what those + + + align:start position:0% +units all right so now what those +equations mean is if you calculate a + + align:start position:0% +equations mean is if you calculate a + + + align:start position:0% +equations mean is if you calculate a +Delta e for the cell the cell voltage uh + + align:start position:0% +Delta e for the cell the cell voltage uh + + + align:start position:0% +Delta e for the cell the cell voltage uh +or the cell potential you can figure out + + align:start position:0% +or the cell potential you can figure out + + + align:start position:0% +or the cell potential you can figure out +whether the reaction will be spontaneous + + align:start position:0% +whether the reaction will be spontaneous + + + align:start position:0% +whether the reaction will be spontaneous +or not because you can use that equation + + align:start position:0% +or not because you can use that equation + + + align:start position:0% +or not because you can use that equation +uh and look at with that particular + + align:start position:0% +uh and look at with that particular + + + align:start position:0% +uh and look at with that particular +Delta e will Delta G be negative will be + + align:start position:0% +Delta e will Delta G be negative will be + + + align:start position:0% +Delta e will Delta G be negative will be +a spontaneous reaction so the first + + align:start position:0% +a spontaneous reaction so the first + + + align:start position:0% +a spontaneous reaction so the first +thing we need to learn how to do is how + + align:start position:0% +thing we need to learn how to do is how + + + align:start position:0% +thing we need to learn how to do is how +to calculate the cell potentials or the + + align:start position:0% +to calculate the cell potentials or the + + + align:start position:0% +to calculate the cell potentials or the +electromotive force and then we can we + + align:start position:0% +electromotive force and then we can we + + + align:start position:0% +electromotive force and then we can we +already know how to convert that to + + align:start position:0% +already know how to convert that to + + + align:start position:0% +already know how to convert that to +Delta G so let's let's look at this + + align:start position:0% +Delta G so let's let's look at this + + + align:start position:0% +Delta G so let's let's look at this +equation here and uh calculate what the + + align:start position:0% +equation here and uh calculate what the + + + align:start position:0% +equation here and uh calculate what the +Delta e the cell potential for this + + align:start position:0% +Delta e the cell potential for this + + + align:start position:0% +Delta e the cell potential for this +particular electrochemical cell that + + align:start position:0% +particular electrochemical cell that + + + align:start position:0% +particular electrochemical cell that +we've been talking + + align:start position:0% +we've been talking + + + align:start position:0% +we've been talking +about so the reaction at the anode which + + align:start position:0% +about so the reaction at the anode which + + + align:start position:0% +about so the reaction at the anode which +we mentioned is this zinc + + align:start position:0% + + + + align:start position:0% + +reaction and this is an + + align:start position:0% +reaction and this is an + + + align:start position:0% +reaction and this is an +oxidation the reaction at the cathode + + align:start position:0% +oxidation the reaction at the cathode + + + align:start position:0% +oxidation the reaction at the cathode +was the reaction with copper copper plus + + align:start position:0% +was the reaction with copper copper plus + + + align:start position:0% +was the reaction with copper copper plus +two and two electrons going to Copper + + align:start position:0% +two and two electrons going to Copper + + + align:start position:0% +two and two electrons going to Copper +solid and that was our reduction + + align:start position:0% +solid and that was our reduction + + + align:start position:0% +solid and that was our reduction +reaction and so now we can just use a + + align:start position:0% +reaction and so now we can just use a + + + align:start position:0% +reaction and so now we can just use a +simple equation to calculate uh Delta e + + align:start position:0% +simple equation to calculate uh Delta e + + + align:start position:0% +simple equation to calculate uh Delta e +KN if we're using the standard reduction + + align:start position:0% +KN if we're using the standard reduction + + + align:start position:0% +KN if we're using the standard reduction +potential for the reaction at the + + align:start position:0% +potential for the reaction at the + + + align:start position:0% +potential for the reaction at the +cathode minus the standard reduction + + align:start position:0% +cathode minus the standard reduction + + + align:start position:0% +cathode minus the standard reduction +potential for the couple at the anode + + align:start position:0% +potential for the couple at the anode + + + align:start position:0% +potential for the couple at the anode +and the point that I want to make here + + align:start position:0% +and the point that I want to make here + + + align:start position:0% +and the point that I want to make here +is that in this fairly simple + + align:start position:0% +is that in this fairly simple + + + align:start position:0% +is that in this fairly simple +equation this term this just e not here + + align:start position:0% +equation this term this just e not here + + + align:start position:0% +equation this term this just e not here +is the standard reduction + + align:start position:0% +is the standard reduction + + + align:start position:0% +is the standard reduction +potential so you don't want to put in + + align:start position:0% +potential so you don't want to put in + + + align:start position:0% +potential so you don't want to put in +something other than that so don't don't + + align:start position:0% +something other than that so don't don't + + + align:start position:0% +something other than that so don't don't +mess around with changing signs of + + align:start position:0% +mess around with changing signs of + + + align:start position:0% +mess around with changing signs of +reactions all you want to do is enter a + + align:start position:0% +reactions all you want to do is enter a + + + align:start position:0% +reactions all you want to do is enter a +reduction potential here and a reduction + + align:start position:0% +reduction potential here and a reduction + + + align:start position:0% +reduction potential here and a reduction +potential here and then this equation + + align:start position:0% +potential here and then this equation + + + align:start position:0% +potential here and then this equation +will always work for you and you'll see + + align:start position:0% +will always work for you and you'll see + + + align:start position:0% +will always work for you and you'll see +what I mean I think a bit more uh when + + align:start position:0% +what I mean I think a bit more uh when + + + align:start position:0% +what I mean I think a bit more uh when +we put that in but if it's the reduction + + align:start position:0% +we put that in but if it's the reduction + + + align:start position:0% +we put that in but if it's the reduction +potential you'd be looking up copper 2 + + align:start position:0% +potential you'd be looking up copper 2 + + + align:start position:0% +potential you'd be looking up copper 2 +plus to Copper solid reduction potential + + align:start position:0% +plus to Copper solid reduction potential + + + align:start position:0% +plus to Copper solid reduction potential +you're looking up zinc plus two to zinc + + align:start position:0% +you're looking up zinc plus two to zinc + + + align:start position:0% +you're looking up zinc plus two to zinc +solid you're you're not caring about + + align:start position:0% +solid you're you're not caring about + + + align:start position:0% +solid you're you're not caring about +which which of these reactions is an + + align:start position:0% +which which of these reactions is an + + + align:start position:0% +which which of these reactions is an +oxidation or which is a reduction at + + align:start position:0% +oxidation or which is a reduction at + + + align:start position:0% +oxidation or which is a reduction at +this point you figured it out by which + + align:start position:0% +this point you figured it out by which + + + align:start position:0% +this point you figured it out by which +is at the cathode if you know what's at + + align:start position:0% +is at the cathode if you know what's at + + + align:start position:0% +is at the cathode if you know what's at +the cathode and you know what's at the + + align:start position:0% +the cathode and you know what's at the + + + align:start position:0% +the cathode and you know what's at the +anode then you enter in the reduction + + align:start position:0% +anode then you enter in the reduction + + + align:start position:0% +anode then you enter in the reduction +potential so let's let's do that and you + + align:start position:0% +potential so let's let's do that and you + + + align:start position:0% +potential so let's let's do that and you +can look up the standard reduction + + align:start position:0% +can look up the standard reduction + + + align:start position:0% +can look up the standard reduction +Potentials in your book there's a table + + align:start position:0% +Potentials in your book there's a table + + + align:start position:0% +Potentials in your book there's a table +in chapter 12 and there's also a table + + align:start position:0% +in chapter 12 and there's also a table + + + align:start position:0% +in chapter 12 and there's also a table +at the end of the book in appendix 2 and + + align:start position:0% +at the end of the book in appendix 2 and + + + align:start position:0% +at the end of the book in appendix 2 and +you can look up the values um and here + + align:start position:0% +you can look up the values um and here + + + align:start position:0% +you can look up the values um and here +they're written as reduction potentials + + align:start position:0% +they're written as reduction potentials + + + align:start position:0% +they're written as reduction potentials +and that's what you'll see in the table + + align:start position:0% +and that's what you'll see in the table + + + align:start position:0% +and that's what you'll see in the table +and uh that's that's what the um + + align:start position:0% +and uh that's that's what the um + + + align:start position:0% +and uh that's that's what the um +information that you can look up and + + align:start position:0% +information that you can look up and + + + align:start position:0% +information that you can look up and +then you have your + + align:start position:0% +then you have your + + + align:start position:0% +then you have your +equation and you will enter in the + + align:start position:0% +equation and you will enter in the + + + align:start position:0% +equation and you will enter in the +reduction potential for the reaction at + + align:start position:0% +reduction potential for the reaction at + + + align:start position:0% +reduction potential for the reaction at +the cathode and enter in the reduction + + align:start position:0% +the cathode and enter in the reduction + + + align:start position:0% +the cathode and enter in the reduction +potential for the reaction at the + + align:start position:0% +potential for the reaction at the + + + align:start position:0% +potential for the reaction at the +anode and here you'll get out a positive + + align:start position:0% +anode and here you'll get out a positive + + + align:start position:0% +anode and here you'll get out a positive +value + + align:start position:0% +value + + + align:start position:0% +value +1.13 volts so again this is the copper + + align:start position:0% +1.13 volts so again this is the copper + + + align:start position:0% +1.13 volts so again this is the copper +reaction this is the zinc reaction so + + align:start position:0% +reaction this is the zinc reaction so + + + align:start position:0% +reaction this is the zinc reaction so +the reason why I want I'm sort of trying + + align:start position:0% +the reason why I want I'm sort of trying + + + align:start position:0% +the reason why I want I'm sort of trying +to jump up and down about the fact that + + align:start position:0% +to jump up and down about the fact that + + + align:start position:0% +to jump up and down about the fact that +you should enter in reduction potentials + + align:start position:0% +you should enter in reduction potentials + + + align:start position:0% +you should enter in reduction potentials +is because if you go if you play around + + align:start position:0% +is because if you go if you play around + + + align:start position:0% +is because if you go if you play around +and all of a sudden switch the signs + + align:start position:0% +and all of a sudden switch the signs + + + align:start position:0% +and all of a sudden switch the signs +then you're going to come out with the + + align:start position:0% +then you're going to come out with the + + + align:start position:0% +then you're going to come out with the +wrong answer and the one of the + + align:start position:0% +wrong answer and the one of the + + + align:start position:0% +wrong answer and the one of the +important points about this answer here + + align:start position:0% +important points about this answer here + + + align:start position:0% +important points about this answer here +is is Delta e positive or negative + + align:start position:0% +is is Delta e positive or negative + + + align:start position:0% +is is Delta e positive or negative +because that's going to tell you if the + + align:start position:0% +because that's going to tell you if the + + + align:start position:0% +because that's going to tell you if the +reaction is spontaneous or not so if you + + align:start position:0% +reaction is spontaneous or not so if you + + + align:start position:0% +reaction is spontaneous or not so if you +do clever things and switch the signs + + align:start position:0% +do clever things and switch the signs + + + align:start position:0% +do clever things and switch the signs +for these around you'll often + + align:start position:0% +for these around you'll often + + + align:start position:0% +for these around you'll often +always come out with the wrong answer + + align:start position:0% +always come out with the wrong answer + + + align:start position:0% +always come out with the wrong answer +there which then affects all the + + align:start position:0% +there which then affects all the + + + align:start position:0% +there which then affects all the +problems that you do after that so as + + align:start position:0% +problems that you do after that so as + + + align:start position:0% +problems that you do after that so as +long as you use this equation and always + + align:start position:0% +long as you use this equation and always + + + align:start position:0% +long as you use this equation and always +enter in a reduction potential you'll be + + align:start position:0% +enter in a reduction potential you'll be + + + align:start position:0% +enter in a reduction potential you'll be +fine and you won't have any of these + + align:start position:0% + + + + align:start position:0% + +problems all right so is the flow of + + align:start position:0% +problems all right so is the flow of + + + align:start position:0% +problems all right so is the flow of +electrons spontaneous for this + + align:start position:0% +electrons spontaneous for this + + + align:start position:0% +electrons spontaneous for this +particular + + align:start position:0% + + + + align:start position:0% + +cell so people are saying yes and that's + + align:start position:0% +cell so people are saying yes and that's + + + align:start position:0% +cell so people are saying yes and that's +the right answer and the way that we + + align:start position:0% +the right answer and the way that we + + + align:start position:0% +the right answer and the way that we +know that is because we remember this + + align:start position:0% +know that is because we remember this + + + align:start position:0% +know that is because we remember this +equation con um comparing Delta e and + + align:start position:0% +equation con um comparing Delta e and + + + align:start position:0% +equation con um comparing Delta e and +Delta G so here if this one is is + + align:start position:0% +Delta G so here if this one is is + + + align:start position:0% +Delta G so here if this one is is +positive then this term will be negative + + align:start position:0% +positive then this term will be negative + + + align:start position:0% +positive then this term will be negative +because this is number of moles which is + + align:start position:0% +because this is number of moles which is + + + align:start position:0% +because this is number of moles which is +always positive and Faraday's constant + + align:start position:0% +always positive and Faraday's constant + + + align:start position:0% +always positive and Faraday's constant +is always positive so if we have a + + align:start position:0% +is always positive so if we have a + + + align:start position:0% +is always positive so if we have a +positive value here then the net sum is + + align:start position:0% +positive value here then the net sum is + + + align:start position:0% +positive value here then the net sum is +negative this will be negative and that + + align:start position:0% +negative this will be negative and that + + + align:start position:0% +negative this will be negative and that +will make uh it spont aneous so if Delta + + align:start position:0% +will make uh it spont aneous so if Delta + + + align:start position:0% +will make uh it spont aneous so if Delta +e is positive Delta G will be negative + + align:start position:0% +e is positive Delta G will be negative + + + align:start position:0% +e is positive Delta G will be negative +Delta and this is true again if it's + + align:start position:0% +Delta and this is true again if it's + + + align:start position:0% +Delta and this is true again if it's +Delta e Delta G not uh same equation so + + align:start position:0% +Delta e Delta G not uh same equation so + + + align:start position:0% +Delta e Delta G not uh same equation so +if Delta G is negative will it be + + align:start position:0% +if Delta G is negative will it be + + + align:start position:0% +if Delta G is negative will it be +spontaneous and uh the answer is yes uh + + align:start position:0% +spontaneous and uh the answer is yes uh + + + align:start position:0% +spontaneous and uh the answer is yes uh +back to previous + + align:start position:0% +back to previous + + + align:start position:0% +back to previous +units so um in in some of the problems + + align:start position:0% +units so um in in some of the problems + + + align:start position:0% +units so um in in some of the problems +in your book that you'll work they'll + + align:start position:0% +in your book that you'll work they'll + + + align:start position:0% +in your book that you'll work they'll +tell you that uh this should this is a + + align:start position:0% +tell you that uh this should this is a + + + align:start position:0% +tell you that uh this should this is a +spontaneous it's electrochemical cell + + align:start position:0% +spontaneous it's electrochemical cell + + + align:start position:0% +spontaneous it's electrochemical cell +and then you can figure out which + + align:start position:0% +and then you can figure out which + + + align:start position:0% +and then you can figure out which +reaction had to be at the anode or which + + align:start position:0% +reaction had to be at the anode or which + + + align:start position:0% +reaction had to be at the anode or which +one had to be at the cathode for that uh + + align:start position:0% +one had to be at the cathode for that uh + + + align:start position:0% +one had to be at the cathode for that uh +through looking calculating the Delta e + + align:start position:0% +through looking calculating the Delta e + + + align:start position:0% +through looking calculating the Delta e +and then figuring out if it positive or + + align:start position:0% +and then figuring out if it positive or + + + align:start position:0% +and then figuring out if it positive or +negative therefore Delta G must be uh + + align:start position:0% +negative therefore Delta G must be uh + + + align:start position:0% +negative therefore Delta G must be uh +positive or negative spontaneous or + + align:start position:0% +positive or negative spontaneous or + + + align:start position:0% +positive or negative spontaneous or +non-spontaneous + + align:start position:0% +non-spontaneous + + + align:start position:0% +non-spontaneous +all right so what do you call it if + + align:start position:0% +all right so what do you call it if + + + align:start position:0% +all right so what do you call it if +there is a spontaneous reaction so here + + align:start position:0% +there is a spontaneous reaction so here + + + align:start position:0% +there is a spontaneous reaction so here +are some terms that you should know you + + align:start position:0% +are some terms that you should know you + + + align:start position:0% +are some terms that you should know you +you have a galvanic cell and that's an + + align:start position:0% +you have a galvanic cell and that's an + + + align:start position:0% +you have a galvanic cell and that's an +electrochemical cell in which the + + align:start position:0% +electrochemical cell in which the + + + align:start position:0% +electrochemical cell in which the +reaction is spontaneous so it can + + align:start position:0% +reaction is spontaneous so it can + + + align:start position:0% +reaction is spontaneous so it can +generate an electron electric current + + align:start position:0% +generate an electron electric current + + + align:start position:0% +generate an electron electric current +and your book uses this and will say oh + + align:start position:0% +and your book uses this and will say oh + + + align:start position:0% +and your book uses this and will say oh +this is a galvanic cell and already then + + align:start position:0% +this is a galvanic cell and already then + + + align:start position:0% +this is a galvanic cell and already then +you should know something about that + + align:start position:0% +you should know something about that + + + align:start position:0% +you should know something about that +reaction uh the other option is an + + align:start position:0% +reaction uh the other option is an + + + align:start position:0% +reaction uh the other option is an +electrolytic cell and in this case + + align:start position:0% +electrolytic cell and in this case + + + align:start position:0% +electrolytic cell and in this case +energy has to be um provided to the + + align:start position:0% +energy has to be um provided to the + + + align:start position:0% +energy has to be um provided to the +Circuit to carry out a non-spontaneous + + align:start position:0% +Circuit to carry out a non-spontaneous + + + align:start position:0% +Circuit to carry out a non-spontaneous +reaction so some you might just want + + align:start position:0% +reaction so some you might just want + + + align:start position:0% +reaction so some you might just want +that non-spontaneous reaction to go and + + align:start position:0% +that non-spontaneous reaction to go and + + + align:start position:0% +that non-spontaneous reaction to go and +then you will have to uh Supply some + + align:start position:0% +then you will have to uh Supply some + + + align:start position:0% +then you will have to uh Supply some +form of of energy to get that reaction + + align:start position:0% +form of of energy to get that reaction + + + align:start position:0% +form of of energy to get that reaction +to work and in in the body um there are + + align:start position:0% +to work and in in the body um there are + + + align:start position:0% +to work and in in the body um there are +both of these kinds of reactions + + align:start position:0% +both of these kinds of reactions + + + align:start position:0% +both of these kinds of reactions +sometimes you would have a reaction an + + align:start position:0% +sometimes you would have a reaction an + + + align:start position:0% +sometimes you would have a reaction an +oxidation Rea reduction reaction that's + + align:start position:0% +oxidation Rea reduction reaction that's + + + align:start position:0% +oxidation Rea reduction reaction that's +spontaneous and that could be used to + + align:start position:0% +spontaneous and that could be used to + + + align:start position:0% +spontaneous and that could be used to +produce some kind of energy it would be + + align:start position:0% +produce some kind of energy it would be + + + align:start position:0% +produce some kind of energy it would be +coupled to an energy generating process + + align:start position:0% +coupled to an energy generating process + + + align:start position:0% +coupled to an energy generating process +in the body other times the body needs a + + align:start position:0% +in the body other times the body needs a + + + align:start position:0% +in the body other times the body needs a +reaction that's unfavorable to go and it + + align:start position:0% +reaction that's unfavorable to go and it + + + align:start position:0% +reaction that's unfavorable to go and it +has to also supply energy to get that + + align:start position:0% +has to also supply energy to get that + + + align:start position:0% +has to also supply energy to get that +reaction to go and we'll talk about + + align:start position:0% +reaction to go and we'll talk about + + + align:start position:0% +reaction to go and we'll talk about +biological examples of these as + + align:start position:0% +biological examples of these as + + + align:start position:0% +biological examples of these as +well all right so then just the brief + + align:start position:0% +well all right so then just the brief + + + align:start position:0% +well all right so then just the brief +summary for this part if the cell + + align:start position:0% +summary for this part if the cell + + + align:start position:0% +summary for this part if the cell +operates spontaneously that can be + + align:start position:0% +operates spontaneously that can be + + + align:start position:0% +operates spontaneously that can be +determined by the uh the Delta e a + + align:start position:0% +determined by the uh the Delta e a + + + align:start position:0% +determined by the uh the Delta e a +positive value means a negative value so + + align:start position:0% +positive value means a negative value so + + + align:start position:0% +positive value means a negative value so +that will be spontaneous and you can get + + align:start position:0% +that will be spontaneous and you can get + + + align:start position:0% +that will be spontaneous and you can get +your Delta e uh from standard reduction + + align:start position:0% +your Delta e uh from standard reduction + + + align:start position:0% +your Delta e uh from standard reduction +potentials for the half reactions + + align:start position:0% + + + + align:start position:0% + +involved all + + align:start position:0% +involved all + + + align:start position:0% +involved all +right now we're going to think about + + align:start position:0% +right now we're going to think about + + + align:start position:0% +right now we're going to think about +what it means if we have certain + + align:start position:0% +what it means if we have certain + + + align:start position:0% +what it means if we have certain +standard reduction potentials if you + + align:start position:0% +standard reduction potentials if you + + + align:start position:0% +standard reduction potentials if you +have a standard reduction potential + + align:start position:0% +have a standard reduction potential + + + align:start position:0% +have a standard reduction potential +that's a large positive number or if you + + align:start position:0% +that's a large positive number or if you + + + align:start position:0% +that's a large positive number or if you +have a standard reduction potential + + align:start position:0% +have a standard reduction potential + + + align:start position:0% +have a standard reduction potential +that's a large negative number or if + + align:start position:0% +that's a large negative number or if + + + align:start position:0% +that's a large negative number or if +you're somewhere in between what does + + align:start position:0% +you're somewhere in between what does + + + align:start position:0% +you're somewhere in between what does +that tell you about the properties of + + align:start position:0% +that tell you about the properties of + + + align:start position:0% +that tell you about the properties of +those particular + + align:start position:0% +those particular + + + align:start position:0% +those particular +elements so a large + + align:start position:0% +elements so a large + + + align:start position:0% +elements so a large +positive standard reduction potential + + align:start position:0% +positive standard reduction potential + + + align:start position:0% +positive standard reduction potential +means that the element is easy to + + align:start position:0% + + + + align:start position:0% + +reduce so let's look at an example for + + align:start position:0% +reduce so let's look at an example for + + + align:start position:0% +reduce so let's look at an example for +this an example we have uh F2 gas plus + + align:start position:0% +this an example we have uh F2 gas plus + + + align:start position:0% +this an example we have uh F2 gas plus +two electrons going to 2f minus and this + + align:start position:0% +two electrons going to 2f minus and this + + + align:start position:0% +two electrons going to 2f minus and this +has a standard reduction potential of + + align:start position:0% +has a standard reduction potential of + + + align:start position:0% +has a standard reduction potential of +plus 2.87 volts and that is a large + + align:start position:0% +plus 2.87 volts and that is a large + + + align:start position:0% +plus 2.87 volts and that is a large +positive + + align:start position:0% +positive + + + align:start position:0% +positive +number so what that's going to mean is + + align:start position:0% +number so what that's going to mean is + + + align:start position:0% +number so what that's going to mean is +that that this is favorable in the + + align:start position:0% +that that this is favorable in the + + + align:start position:0% +that that this is favorable in the +direction is written and favorable means + + align:start position:0% +direction is written and favorable means + + + align:start position:0% +direction is written and favorable means +it's easy to add electrons this wants to + + align:start position:0% +it's easy to add electrons this wants to + + + align:start position:0% +it's easy to add electrons this wants to +be reduced to F minus it's happy that + + align:start position:0% +be reduced to F minus it's happy that + + + align:start position:0% +be reduced to F minus it's happy that +way if it has a large positive sign for + + align:start position:0% +way if it has a large positive sign for + + + align:start position:0% +way if it has a large positive sign for +for the standard reduction potential + + align:start position:0% +for the standard reduction potential + + + align:start position:0% +for the standard reduction potential +then Delta G will be negative which will + + align:start position:0% +then Delta G will be negative which will + + + align:start position:0% +then Delta G will be negative which will +be SP uh favorable or spontaneous in + + align:start position:0% +be SP uh favorable or spontaneous in + + + align:start position:0% +be SP uh favorable or spontaneous in +that direction so this is a favorable + + align:start position:0% +that direction so this is a favorable + + + align:start position:0% +that direction so this is a favorable +reaction F2 is easy to reduce it wants + + align:start position:0% +reaction F2 is easy to reduce it wants + + + align:start position:0% +reaction F2 is easy to reduce it wants +to be reduced + + align:start position:0% + + + + align:start position:0% + +so is it a good oxidating um oxidizing + + align:start position:0% + + + + align:start position:0% + +agent + + align:start position:0% +agent + + + align:start position:0% +agent +yes so again a good oxidizing agent + + align:start position:0% +yes so again a good oxidizing agent + + + align:start position:0% +yes so again a good oxidizing agent +oxidizes other things and is reduced + + align:start position:0% +oxidizes other things and is reduced + + + align:start position:0% +oxidizes other things and is reduced +itself so it runs around and tries to + + align:start position:0% +itself so it runs around and tries to + + + align:start position:0% +itself so it runs around and tries to +oxidize other stuff which means that it + + align:start position:0% +oxidize other stuff which means that it + + + align:start position:0% +oxidize other stuff which means that it +gets reduced which is what it wants to + + align:start position:0% +gets reduced which is what it wants to + + + align:start position:0% +gets reduced which is what it wants to +be it wants to be reduced so this is a + + align:start position:0% +be it wants to be reduced so this is a + + + align:start position:0% +be it wants to be reduced so this is a +good oxidizing agent + + align:start position:0% + + + + align:start position:0% + +so if we look at the + + align:start position:0% +so if we look at the + + + align:start position:0% +so if we look at the +couple here + + align:start position:0% +couple here + + + align:start position:0% +couple here +F2 um slf minus this reduction couple + + align:start position:0% +F2 um slf minus this reduction couple + + + align:start position:0% +F2 um slf minus this reduction couple +with the large positive value what we + + align:start position:0% +with the large positive value what we + + + align:start position:0% +with the large positive value what we +can say is that the oxidized + + align:start position:0% +can say is that the oxidized + + + align:start position:0% +can say is that the oxidized +species and that's this one here the F2 + + align:start position:0% +species and that's this one here the F2 + + + align:start position:0% +species and that's this one here the F2 +is very oxidizing it's a good oxidizing + + align:start position:0% +is very oxidizing it's a good oxidizing + + + align:start position:0% +is very oxidizing it's a good oxidizing +agent + + align:start position:0% + + + + align:start position:0% + +and this is a table from your book so + + align:start position:0% +and this is a table from your book so + + + align:start position:0% +and this is a table from your book so +it's not in your handout but you can + + align:start position:0% +it's not in your handout but you can + + + align:start position:0% +it's not in your handout but you can +look it up and uh here's the page number + + align:start position:0% +look it up and uh here's the page number + + + align:start position:0% +look it up and uh here's the page number +and this is the one we just looked at f2 + + align:start position:0% +and this is the one we just looked at f2 + + + align:start position:0% +and this is the one we just looked at f2 +to F minus and it says right on the top + + align:start position:0% +to F minus and it says right on the top + + + align:start position:0% +to F minus and it says right on the top +oxidized form which is F2 is strongly + + align:start position:0% +oxidized form which is F2 is strongly + + + align:start position:0% +oxidized form which is F2 is strongly +oxidizing so it like it has a big + + align:start position:0% +oxidizing so it like it has a big + + + align:start position:0% +oxidizing so it like it has a big +positive number it's at the very top of + + align:start position:0% +positive number it's at the very top of + + + align:start position:0% +positive number it's at the very top of +the table big positive number it likes + + align:start position:0% +the table big positive number it likes + + + align:start position:0% +the table big positive number it likes +to be reduced I.E it likes to oxidize + + align:start position:0% +to be reduced I.E it likes to oxidize + + + align:start position:0% +to be reduced I.E it likes to oxidize +other + + align:start position:0% +other + + + align:start position:0% +other +things so now let's go to the bottom of + + align:start position:0% +things so now let's go to the bottom of + + + align:start position:0% +things so now let's go to the bottom of +the table and see what we can say about + + align:start position:0% +the table and see what we can say about + + + align:start position:0% +the table and see what we can say about +this uh lithium uh plus lithium solid + + align:start position:0% +this uh lithium uh plus lithium solid + + + align:start position:0% +this uh lithium uh plus lithium solid +couple so that had a large negative + + align:start position:0% +couple so that had a large negative + + + align:start position:0% +couple so that had a large negative +value for the standard reduction + + align:start position:0% +value for the standard reduction + + + align:start position:0% +value for the standard reduction +potential and that means it's hard to + + align:start position:0% +potential and that means it's hard to + + + align:start position:0% +potential and that means it's hard to +reduce so let's look at that so we have + + align:start position:0% +reduce so let's look at that so we have + + + align:start position:0% +reduce so let's look at that so we have +lithium plus one plus one electron going + + align:start position:0% +lithium plus one plus one electron going + + + align:start position:0% +lithium plus one plus one electron going +to lithium solid and that reduction is + + align:start position:0% +to lithium solid and that reduction is + + + align:start position:0% +to lithium solid and that reduction is +listed with a standard reduction + + align:start position:0% +listed with a standard reduction + + + align:start position:0% +listed with a standard reduction +potential of minus + + align:start position:0% +potential of minus + + + align:start position:0% +potential of minus +3.45 volts so that's a large negative + + align:start position:0% +3.45 volts so that's a large negative + + + align:start position:0% +3.45 volts so that's a large negative +number so if it's a large negative + + align:start position:0% +number so if it's a large negative + + + align:start position:0% +number so if it's a large negative +number that means it's hard to add + + align:start position:0% +number that means it's hard to add + + + align:start position:0% +number that means it's hard to add +electrons this direction as written is + + align:start position:0% +electrons this direction as written is + + + align:start position:0% +electrons this direction as written is +not particularly favorable lithium plus + + align:start position:0% +not particularly favorable lithium plus + + + align:start position:0% +not particularly favorable lithium plus +one doesn't want to go to lithium solid + + align:start position:0% +one doesn't want to go to lithium solid + + + align:start position:0% +one doesn't want to go to lithium solid +uh it's hard to add that electron that + + align:start position:0% +uh it's hard to add that electron that + + + align:start position:0% +uh it's hard to add that electron that +direction of the reaction the forward + + align:start position:0% +direction of the reaction the forward + + + align:start position:0% +direction of the reaction the forward +direction would not be very favorable + + align:start position:0% +direction would not be very favorable + + + align:start position:0% +direction would not be very favorable +Delta G would be positive it would be a + + align:start position:0% +Delta G would be positive it would be a + + + align:start position:0% +Delta G would be positive it would be a +large positive number so it doesn't want + + align:start position:0% +large positive number so it doesn't want + + + align:start position:0% +large positive number so it doesn't want +to go in that + + align:start position:0% +to go in that + + + align:start position:0% +to go in that +direction so is is lithium plus one a + + align:start position:0% +direction so is is lithium plus one a + + + align:start position:0% +direction so is is lithium plus one a +good oxidizing + + align:start position:0% +good oxidizing + + + align:start position:0% +good oxidizing +agent + + align:start position:0% +agent + + + align:start position:0% +agent +no but it's a good reducing agent or + + align:start position:0% +no but it's a good reducing agent or + + + align:start position:0% +no but it's a good reducing agent or +lithium solid is a good reducing agent + + align:start position:0% +lithium solid is a good reducing agent + + + align:start position:0% +lithium solid is a good reducing agent +so lithium solid reduc likes to reduce + + align:start position:0% +so lithium solid reduc likes to reduce + + + align:start position:0% +so lithium solid reduc likes to reduce +other elements it likes to get oxidized + + align:start position:0% +other elements it likes to get oxidized + + + align:start position:0% +other elements it likes to get oxidized +it w this reaction is favorable in the + + align:start position:0% +it w this reaction is favorable in the + + + align:start position:0% +it w this reaction is favorable in the +reverse Direction so the lithium solid + + align:start position:0% +reverse Direction so the lithium solid + + + align:start position:0% +reverse Direction so the lithium solid +over here would be very happy to be + + align:start position:0% +over here would be very happy to be + + + align:start position:0% +over here would be very happy to be +lithium + + + align:start position:0% +lithium + + + + align:start position:0% +lithium + +one so lithium solid is a good reducing + + align:start position:0% +one so lithium solid is a good reducing + + + align:start position:0% +one so lithium solid is a good reducing +agent so if we look again at this couple + + align:start position:0% +agent so if we look again at this couple + + + align:start position:0% +agent so if we look again at this couple +the lithium plus one lithium couple with + + align:start position:0% +the lithium plus one lithium couple with + + + align:start position:0% +the lithium plus one lithium couple with +a large negative standard reduction + + align:start position:0% +a large negative standard reduction + + + align:start position:0% +a large negative standard reduction +potential we find that the reduced + + align:start position:0% +potential we find that the reduced + + + align:start position:0% +potential we find that the reduced +species the reduced species here is + + align:start position:0% +species the reduced species here is + + + align:start position:0% +species the reduced species here is +lithium solid the reduced species is + + align:start position:0% +lithium solid the reduced species is + + + align:start position:0% +lithium solid the reduced species is +very reducing so it wants to be oxidized + + align:start position:0% +very reducing so it wants to be oxidized + + + align:start position:0% +very reducing so it wants to be oxidized +itself it wants to reduce other things + + align:start position:0% +itself it wants to reduce other things + + + align:start position:0% +itself it wants to reduce other things +it's a good reducing + + align:start position:0% +it's a good reducing + + + align:start position:0% +it's a good reducing +agent so if we go back to our table down + + align:start position:0% +agent so if we go back to our table down + + + align:start position:0% +agent so if we go back to our table down +here it says reduced form is strongly + + align:start position:0% +here it says reduced form is strongly + + + align:start position:0% +here it says reduced form is strongly +reducing so up here on the far corner on + + align:start position:0% +reducing so up here on the far corner on + + + align:start position:0% +reducing so up here on the far corner on +the left hand side + + align:start position:0% +the left hand side + + + align:start position:0% +the left hand side +the oxidized form is strongly oxidizing + + align:start position:0% +the oxidized form is strongly oxidizing + + + align:start position:0% +the oxidized form is strongly oxidizing +down here on the right hand side the + + align:start position:0% +down here on the right hand side the + + + align:start position:0% +down here on the right hand side the +reduced form is strongly reducing so + + align:start position:0% +reduced form is strongly reducing so + + + align:start position:0% +reduced form is strongly reducing so +you'll be asked about various things in + + align:start position:0% +you'll be asked about various things in + + + align:start position:0% +you'll be asked about various things in +between is something a better oxidizing + + align:start position:0% +between is something a better oxidizing + + + align:start position:0% +between is something a better oxidizing +agent than something else is something a + + align:start position:0% +agent than something else is something a + + + align:start position:0% +agent than something else is something a +better reducing agent than something + + align:start position:0% +better reducing agent than something + + + align:start position:0% +better reducing agent than something +else and if you remember uh these parts + + align:start position:0% +else and if you remember uh these parts + + + align:start position:0% +else and if you remember uh these parts +oxidized form up here where where E + + align:start position:0% +oxidized form up here where where E + + + align:start position:0% +oxidized form up here where where E +standard reduction potential e not is + + align:start position:0% +standard reduction potential e not is + + + align:start position:0% +standard reduction potential e not is +positive oxidized form is strongly + + align:start position:0% +positive oxidized form is strongly + + + align:start position:0% +positive oxidized form is strongly +oxidizing down here where you have a + + align:start position:0% +oxidizing down here where you have a + + + align:start position:0% +oxidizing down here where you have a +negative number reduced form is strongly + + align:start position:0% + + + + align:start position:0% + +reducing so this makes sense from what + + align:start position:0% +reducing so this makes sense from what + + + align:start position:0% +reducing so this makes sense from what +you learned before actually and this is + + align:start position:0% +you learned before actually and this is + + + align:start position:0% +you learned before actually and this is +another table from from your book so I + + align:start position:0% +another table from from your book so I + + + align:start position:0% +another table from from your book so I +didn't put it in the handout but we + + align:start position:0% +didn't put it in the handout but we + + + align:start position:0% +didn't put it in the handout but we +talked about uh Florine over here we + + align:start position:0% +talked about uh Florine over here we + + + align:start position:0% +talked about uh Florine over here we +talked about lithium this has a big + + align:start position:0% +talked about lithium this has a big + + + align:start position:0% +talked about lithium this has a big +positive number over here so it's easy + + align:start position:0% +positive number over here so it's easy + + + align:start position:0% +positive number over here so it's easy +it's you have easy to reduce these are + + align:start position:0% +it's you have easy to reduce these are + + + align:start position:0% +it's you have easy to reduce these are +good oxidizing agents and on the other + + align:start position:0% +good oxidizing agents and on the other + + + align:start position:0% +good oxidizing agents and on the other +side these want to be oxidized they're + + align:start position:0% +side these want to be oxidized they're + + + align:start position:0% +side these want to be oxidized they're +good reducing agents Florine minus has a + + align:start position:0% +good reducing agents Florine minus has a + + + align:start position:0% +good reducing agents Florine minus has a +noble gas + + align:start position:0% +noble gas + + + align:start position:0% +noble gas +configuration and lithium plus has a + + align:start position:0% +configuration and lithium plus has a + + + align:start position:0% +configuration and lithium plus has a +noble gas configuration so it makes + + align:start position:0% +noble gas configuration so it makes + + + align:start position:0% +noble gas configuration so it makes +sense from some of the trends you talked + + align:start position:0% +sense from some of the trends you talked + + + align:start position:0% +sense from some of the trends you talked +about earlier in terms of whether + + align:start position:0% +about earlier in terms of whether + + + align:start position:0% +about earlier in terms of whether +something's favorable or not whether it + + align:start position:0% +something's favorable or not whether it + + + align:start position:0% +something's favorable or not whether it +likes to be in the plus one state or + + align:start position:0% +likes to be in the plus one state or + + + align:start position:0% +likes to be in the plus one state or +prefers to be in the minus one state can + + align:start position:0% +prefers to be in the minus one state can + + + align:start position:0% +prefers to be in the minus one state can +all come out of these Ox of these uh + + align:start position:0% +all come out of these Ox of these uh + + + align:start position:0% +all come out of these Ox of these uh +reduction potential numbers and you can + + align:start position:0% +reduction potential numbers and you can + + + align:start position:0% +reduction potential numbers and you can +figure out you know which direction is + + align:start position:0% +figure out you know which direction is + + + align:start position:0% +figure out you know which direction is +favorable the reduction or the + + align:start position:0% + + + + align:start position:0% + +oxidation so let's let's take a look at + + align:start position:0% +oxidation so let's let's take a look at + + + align:start position:0% +oxidation so let's let's take a look at +an example here uh of this uh this cell + + align:start position:0% +an example here uh of this uh this cell + + + align:start position:0% +an example here uh of this uh this cell +potential and think about what are good + + align:start position:0% +potential and think about what are good + + + align:start position:0% +potential and think about what are good +oxidizing and reduction uh oxidizing + + align:start position:0% +oxidizing and reduction uh oxidizing + + + align:start position:0% +oxidizing and reduction uh oxidizing +agents and reduction + + align:start position:0% +agents and reduction + + + align:start position:0% +agents and reduction +agents so there uh these two two couples + + align:start position:0% +agents so there uh these two two couples + + + align:start position:0% +agents so there uh these two two couples +over here we're going to look up and + + align:start position:0% +over here we're going to look up and + + + align:start position:0% +over here we're going to look up and +that's hard to see so I'll just go back + + align:start position:0% +that's hard to see so I'll just go back + + + align:start position:0% +that's hard to see so I'll just go back +to this all right so what's happening in + + align:start position:0% +to this all right so what's happening in + + + align:start position:0% +to this all right so what's happening in +this particular + + align:start position:0% + + + + align:start position:0% + +reaction so we have two irons + + + align:start position:0% +reaction so we have two irons + + + + align:start position:0% +reaction so we have two irons + +three and two + + align:start position:0% +three and two + + + align:start position:0% +three and two +electrons going to two + + align:start position:0% +electrons going to two + + + align:start position:0% +electrons going to two +iron + + + align:start position:0% + + + + align:start position:0% + +two so is this a a reduction or an + + align:start position:0% + + + + align:start position:0% + +oxidation so as written it's a reduction + + align:start position:0% + + + + align:start position:0% + +so that means it would take place at the + + align:start position:0% +so that means it would take place at the + + + align:start position:0% +so that means it would take place at the +anode or + + align:start position:0% +anode or + + + align:start position:0% +anode or +cathode at the + + align:start position:0% + + + + align:start position:0% + +cathode all right the other reaction we + + align:start position:0% +cathode all right the other reaction we + + + align:start position:0% +cathode all right the other reaction we +have is 2 I minus going to I2 solid plus + + align:start position:0% +have is 2 I minus going to I2 solid plus + + + align:start position:0% +have is 2 I minus going to I2 solid plus + + align:start position:0% + + + align:start position:0% +electrons as it needs to be balanced so + + align:start position:0% +electrons as it needs to be balanced so + + + align:start position:0% +electrons as it needs to be balanced so +this would be an + + align:start position:0% + + + + align:start position:0% + +oxidation and so it should take place at + + align:start position:0% +oxidation and so it should take place at + + + align:start position:0% +oxidation and so it should take place at +the + + align:start position:0% +the + + + align:start position:0% +the +anode so now we can calculate the cell + + align:start position:0% +anode so now we can calculate the cell + + + align:start position:0% +anode so now we can calculate the cell +potential for this particular reaction + + align:start position:0% +potential for this particular reaction + + + align:start position:0% +potential for this particular reaction +the Delta e KN for the + + align:start position:0% +the Delta e KN for the + + + align:start position:0% +the Delta e KN for the +cell and that will equal the uh Delta e + + align:start position:0% +cell and that will equal the uh Delta e + + + align:start position:0% +cell and that will equal the uh Delta e +for the cathode + + align:start position:0% +for the cathode + + + align:start position:0% +for the cathode +reaction minus the Delta e for the + + align:start position:0% +reaction minus the Delta e for the + + + align:start position:0% +reaction minus the Delta e for the +anode + + align:start position:0% +anode + + + align:start position:0% +anode +reaction so the Delta e for the cathode + + align:start position:0% +reaction so the Delta e for the cathode + + + align:start position:0% +reaction so the Delta e for the cathode +reaction uh and you were given this in + + align:start position:0% +reaction uh and you were given this in + + + align:start position:0% +reaction uh and you were given this in +in your handouts we have plus we have + + align:start position:0% +in your handouts we have plus we have + + + align:start position:0% +in your handouts we have plus we have +plus + + align:start position:0% +plus + + + align:start position:0% +plus + + align:start position:0% + + + align:start position:0% +volts + + align:start position:0% +volts + + + align:start position:0% +volts +minus plus + + align:start position:0% +minus plus + + + align:start position:0% +minus plus +535 Volts for the reaction happening at + + align:start position:0% +535 Volts for the reaction happening at + + + align:start position:0% +535 Volts for the reaction happening at +the + + align:start position:0% +the + + + align:start position:0% +the +anode and so that will equal + + align:start position:0% + + + + align:start position:0% + +0.235 + + align:start position:0% +0.235 + + + align:start position:0% +0.235 +volts and so will that be + + align:start position:0% +volts and so will that be + + + align:start position:0% +volts and so will that be +spontaneous yes so it will be + + align:start position:0% +spontaneous yes so it will be + + + align:start position:0% +spontaneous yes so it will be +spontaneous so Delta e e is positive so + + align:start position:0% +spontaneous so Delta e e is positive so + + + align:start position:0% +spontaneous so Delta e e is positive so +Delta G will be negative so we'll have a + + align:start position:0% +Delta G will be negative so we'll have a + + + align:start position:0% +Delta G will be negative so we'll have a +spontaneous + + align:start position:0% +spontaneous + + + align:start position:0% +spontaneous +reaction now let's consider which are + + align:start position:0% +reaction now let's consider which are + + + align:start position:0% +reaction now let's consider which are +the better oxidizing and reducing + + align:start position:0% + + + + align:start position:0% + +agents so for + + align:start position:0% + + + + align:start position:0% + +better better oxidizing + + align:start position:0% + + + + align:start position:0% + +agent is it iron + three + + align:start position:0% +agent is it iron + three + + + align:start position:0% +agent is it iron + three +or iodide + + align:start position:0% +or iodide + + + align:start position:0% +or iodide +2 which is a better oxidizing agent and + + align:start position:0% +2 which is a better oxidizing agent and + + + align:start position:0% +2 which is a better oxidizing agent and +we can go back to the Chart here's the + + align:start position:0% +we can go back to the Chart here's the + + + align:start position:0% +we can go back to the Chart here's the +iron and below it is the iodide + + align:start position:0% +iron and below it is the iodide + + + align:start position:0% +iron and below it is the iodide +reaction so which is + + align:start position:0% + + + + align:start position:0% + +better so iron I heard I think I heard + + align:start position:0% +better so iron I heard I think I heard + + + align:start position:0% +better so iron I heard I think I heard +some people say + + align:start position:0% +some people say + + + align:start position:0% +some people say +iron + + + align:start position:0% +iron + + + + align:start position:0% +iron + +three so that should be a better + + align:start position:0% +three so that should be a better + + + align:start position:0% +three so that should be a better +oxidizing agent so again and if you look + + align:start position:0% +oxidizing agent so again and if you look + + + align:start position:0% +oxidizing agent so again and if you look +at where they are the things on this + + align:start position:0% +at where they are the things on this + + + align:start position:0% +at where they are the things on this +side at the top are the most oxidizing + + align:start position:0% +side at the top are the most oxidizing + + + align:start position:0% +side at the top are the most oxidizing +or the best oxidizing agent so iron plus + + align:start position:0% +or the best oxidizing agent so iron plus + + + align:start position:0% +or the best oxidizing agent so iron plus +three is there it's going to be uh + + align:start position:0% +three is there it's going to be uh + + + align:start position:0% +three is there it's going to be uh +better and we can also think about this + + align:start position:0% +better and we can also think about this + + + align:start position:0% +better and we can also think about this +in terms of the spontaneous reaction + + align:start position:0% +in terms of the spontaneous reaction + + + align:start position:0% +in terms of the spontaneous reaction +this is + + align:start position:0% +this is + + + align:start position:0% +this is +spontaneous and the iron plus three here + + align:start position:0% +spontaneous and the iron plus three here + + + align:start position:0% +spontaneous and the iron plus three here +is is being is being reduced so it's + + align:start position:0% +is is being is being reduced so it's + + + align:start position:0% +is is being is being reduced so it's +acting as an oxidizing reagent + + align:start position:0% +acting as an oxidizing reagent + + + align:start position:0% +acting as an oxidizing reagent +and that's causing the reaction to be + + align:start position:0% +and that's causing the reaction to be + + + align:start position:0% +and that's causing the reaction to be +spontaneous and if we talk about the + + align:start position:0% +spontaneous and if we talk about the + + + align:start position:0% +spontaneous and if we talk about the +better better reducing agent the + + align:start position:0% +better better reducing agent the + + + align:start position:0% +better better reducing agent the +reducing agent is the thing that wants + + align:start position:0% +reducing agent is the thing that wants + + + align:start position:0% +reducing agent is the thing that wants +to get + + align:start position:0% +to get + + + align:start position:0% +to get +oxidized and if we consider IUS or iron + + align:start position:0% +oxidized and if we consider IUS or iron + + + align:start position:0% +oxidized and if we consider IUS or iron ++ 2 which is + + align:start position:0% + + + + align:start position:0% + +better I minus is going to be + + align:start position:0% +better I minus is going to be + + + align:start position:0% +better I minus is going to be +better and again it's down here down + + align:start position:0% +better and again it's down here down + + + align:start position:0% +better and again it's down here down +here we have the reduced forms are + + align:start position:0% +here we have the reduced forms are + + + align:start position:0% +here we have the reduced forms are +strongly reducing this is the reduced + + align:start position:0% +strongly reducing this is the reduced + + + align:start position:0% +strongly reducing this is the reduced +form so it's on this end of the table + + align:start position:0% +form so it's on this end of the table + + + align:start position:0% +form so it's on this end of the table +also uh that's the reaction that's + + align:start position:0% +also uh that's the reaction that's + + + align:start position:0% +also uh that's the reaction that's +happening here and it's spontaneous it + + align:start position:0% +happening here and it's spontaneous it + + + align:start position:0% +happening here and it's spontaneous it +has and if you talk about the two + + align:start position:0% +has and if you talk about the two + + + align:start position:0% +has and if you talk about the two +reduction potentials you can figure that + + align:start position:0% +reduction potentials you can figure that + + + align:start position:0% +reduction potentials you can figure that +out okay see you on + + align:start position:0% + + + + align:start position:0% + +Wednesday \ No newline at end of file diff --git a/1LEYgS8Wzsk.txt b/1LEYgS8Wzsk.txt new file mode 100644 index 0000000000000000000000000000000000000000..16e19775e332a6814a85c14193f469d5e1acd63c --- /dev/null +++ b/1LEYgS8Wzsk.txt @@ -0,0 +1,16548 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +to view additional materials from + + align:start position:0% +to view additional materials from + + + align:start position:0% +to view additional materials from +hundreds of MIT courses visit MIT open + + align:start position:0% +hundreds of MIT courses visit MIT open + + + align:start position:0% +hundreds of MIT courses visit MIT open +courseware at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu okay good let us + + align:start position:0% +ocw.mit.edu okay good let us + + + align:start position:0% +ocw.mit.edu okay good let us +start so um so last time we talked + + align:start position:0% +start so um so last time we talked + + + align:start position:0% +start so um so last time we talked +about finding the space time + + align:start position:0% +about finding the space time + + + align:start position:0% +about finding the space time +geometry produced by this re + + align:start position:0% +geometry produced by this re + + + align:start position:0% +geometry produced by this re +brain so just by based on + + align:start position:0% +brain so just by based on + + + align:start position:0% +brain so just by based on +symmetry you can write down the matric + + align:start position:0% +symmetry you can write down the matric + + + align:start position:0% +symmetry you can write down the matric +as the + + align:start position:0% + + + + align:start position:0% + +following say some + + align:start position:0% +following say some + + + align:start position:0% +following say some +function and then a minkovski + + align:start position:0% + + + + align:start position:0% + +matric i movy matric + + align:start position:0% +matric i movy matric + + + align:start position:0% +matric i movy matric +for the 3+ One + + align:start position:0% + + + + align:start position:0% + +Direction and + + align:start position:0% +Direction and + + + align:start position:0% +Direction and +then the path for the transverse + + align:start position:0% +then the path for the transverse + + + align:start position:0% +then the path for the transverse +Direction which you have AOS which you + + align:start position:0% +Direction which you have AOS which you + + + align:start position:0% +Direction which you have AOS which you +have a rotation + + align:start position:0% +have a rotation + + + align:start position:0% +have a rotation +symmetry so you should think of H the + + align:start position:0% +symmetry so you should think of H the + + + align:start position:0% +symmetry so you should think of H the +this + + align:start position:0% +this + + + align:start position:0% +this +rean as a point in R + + align:start position:0% +rean as a point in R + + + align:start position:0% +rean as a point in R +six then there's a spherical symmetry in + + align:start position:0% +six then there's a spherical symmetry in + + + align:start position:0% +six then there's a spherical symmetry in +R6 around this point and then and then + + align:start position:0% +R6 around this point and then and then + + + align:start position:0% +R6 around this point and then and then +there are other 3 + One Direction which + + align:start position:0% +there are other 3 + One Direction which + + + align:start position:0% +there are other 3 + One Direction which +is this 3 + y direction okay so when you + + align:start position:0% +is this 3 + y direction okay so when you + + + align:start position:0% +is this 3 + y direction okay so when you +solve the Einstein + + align:start position:0% +solve the Einstein + + + align:start position:0% +solve the Einstein +equation when you solve the Einstein + + align:start position:0% +equation when you solve the Einstein + + + align:start position:0% +equation when you solve the Einstein +equation then you find this + + align:start position:0% +equation then you find this + + + align:start position:0% +equation then you find this +FH just replace it can be solved + + align:start position:0% + + + + align:start position:0% + +explicitly by the following form some + + align:start position:0% +explicitly by the following form some + + + align:start position:0% +explicitly by the following form some +other function + + align:start position:0% +other function + + + align:start position:0% +other function +H by the same + + align:start position:0% +H by the same + + + align:start position:0% +H by the same +function + + align:start position:0% +function + + + align:start position:0% +function +with h given + + align:start position:0% + + + + align:start position:0% + +by and R is a + + align:start position:0% +by and R is a + + + align:start position:0% +by and R is a +constant which given by the following + + align:start position:0% + + + + align:start position:0% + +form so I essentially have the + + align:start position:0% +form so I essentially have the + + + align:start position:0% +form so I essentially have the +form of some + + align:start position:0% + + + + align:start position:0% + +constants Newton constant and and the + + align:start position:0% +constants Newton constant and and the + + + align:start position:0% +constants Newton constant and and the +times the tension of the this three + + align:start position:0% +times the tension of the this three + + + align:start position:0% +times the tension of the this three +brain and then if have angle of them and + + align:start position:0% +brain and then if have angle of them and + + + align:start position:0% +brain and then if have angle of them and +then this can also be if you written + + align:start position:0% +then this can also be if you written + + + align:start position:0% +then this can also be if you written +everything in terms of alpha Prime uh GS + + align:start position:0% +everything in terms of alpha Prime uh GS + + + align:start position:0% +everything in terms of alpha Prime uh GS +and Alpha Prime can written as 4 Pi GS + + align:start position:0% +and Alpha Prime can written as 4 Pi GS + + + align:start position:0% +and Alpha Prime can written as 4 Pi GS +and Alpha Prime squ + + align:start position:0% + + + + align:start position:0% + +okay so this R so this is just like the + + align:start position:0% +okay so this R so this is just like the + + + align:start position:0% +okay so this R so this is just like the +what you normally see in the SWAT short + + align:start position:0% +what you normally see in the SWAT short + + + align:start position:0% +what you normally see in the SWAT short +matric is like G time the mass except + + align:start position:0% +matric is like G time the mass except + + + align:start position:0% +matric is like G time the mass except +because of the translation symmetry in + + align:start position:0% +because of the translation symmetry in + + + align:start position:0% +because of the translation symmetry in +this re + One Direction so we have the + + align:start position:0% +this re + One Direction so we have the + + + align:start position:0% +this re + One Direction so we have the +tension appear here so GN is + + align:start position:0% +tension appear here so GN is + + + align:start position:0% +tension appear here so GN is +proportional to solution Conant is + + align:start position:0% +proportional to solution Conant is + + + align:start position:0% +proportional to solution Conant is +proportional to GS squ and T3 is propor + + align:start position:0% +proportional to GS squ and T3 is propor + + + align:start position:0% +proportional to GS squ and T3 is propor +to one over GS so this product be + + align:start position:0% +to one over GS so this product be + + + align:start position:0% +to one over GS so this product be +proportion to + + align:start position:0% +proportion to + + + align:start position:0% +proportion to +GS okay and there's n of them so there's + + align:start position:0% +GS okay and there's n of them so there's + + + align:start position:0% +GS okay and there's n of them so there's +n here and on dimensional + + align:start position:0% +n here and on dimensional + + + align:start position:0% +n here and on dimensional +ground this is dimension four so you + + align:start position:0% +ground this is dimension four so you + + + align:start position:0% +ground this is dimension four so you +have Alpha Prime Square here okay so + + align:start position:0% +have Alpha Prime Square here okay so + + + align:start position:0% +have Alpha Prime Square here okay so +again you can write down everything on + + align:start position:0% +again you can write down everything on + + + align:start position:0% +again you can write down everything on +dimensional ground and the only thing is + + align:start position:0% +dimensional ground and the only thing is + + + align:start position:0% +dimensional ground and the only thing is +just this four Pi you have to be careful + + align:start position:0% + + + + align:start position:0% + +okay so so this is the full this rebrin + + align:start position:0% +okay so so this is the full this rebrin + + + align:start position:0% +okay so so this is the full this rebrin +matric so this is the full this rebrin + + align:start position:0% +matric so this is the full this rebrin + + + align:start position:0% +matric so this is the full this rebrin +matric so now now let's understand a + + align:start position:0% +matric so now now let's understand a + + + align:start position:0% +matric so now now let's understand a +little + + align:start position:0% +little + + + align:start position:0% +little +bit physics of this matric so try to + + align:start position:0% +bit physics of this matric so try to + + + align:start position:0% +bit physics of this matric so try to +which give us a deeper understanding of + + align:start position:0% +which give us a deeper understanding of + + + align:start position:0% +which give us a deeper understanding of +the physics of this repr + + align:start position:0% +the physics of this repr + + + align:start position:0% +the physics of this repr +brains so + + align:start position:0% +brains so + + + align:start position:0% +brains so +first let's consider whyus regime + + align:start position:0% +first let's consider whyus regime + + + align:start position:0% +first let's consider whyus regime +of R okay so let's consider say R first + + align:start position:0% +of R okay so let's consider say R first + + + align:start position:0% +of R okay so let's consider say R first +consider R go to + + align:start position:0% +consider R go to + + + align:start position:0% +consider R go to +Infinity so in AR go to Infinity HR just + + align:start position:0% +Infinity so in AR go to Infinity HR just + + + align:start position:0% +Infinity so in AR go to Infinity HR just +become + + align:start position:0% +become + + + align:start position:0% +become +one H just become + + align:start position:0% +one H just become + + + align:start position:0% +one H just become +one okay and then you just recover U + + align:start position:0% +one okay and then you just recover U + + + align:start position:0% +one okay and then you just recover U +um 10 dimensional minkovski + + align:start position:0% +um 10 dimensional minkovski + + + align:start position:0% +um 10 dimensional minkovski +matric okay so this is very easy to + + align:start position:0% +matric okay so this is very easy to + + + align:start position:0% +matric okay so this is very easy to +understand you're infinite away from the + + align:start position:0% +understand you're infinite away from the + + + align:start position:0% +understand you're infinite away from the +this Rebrand of course you don't feel + + align:start position:0% +this Rebrand of course you don't feel + + + align:start position:0% +this Rebrand of course you don't feel +anything and so you just recover the uh + + align:start position:0% +anything and so you just recover the uh + + + align:start position:0% +anything and so you just recover the uh +uh 10 dimensional movi space time so + + align:start position:0% +uh 10 dimensional movi space time so + + + align:start position:0% +uh 10 dimensional movi space time so +here is one here is one uh this is a + + align:start position:0% +here is one here is one uh this is a + + + align:start position:0% +here is one here is one uh this is a +funny way to write down 10 dimensional + + align:start position:0% +funny way to write down 10 dimensional + + + align:start position:0% +funny way to write down 10 dimensional +movi space time so this is just a flat + + align:start position:0% +movi space time so this is just a flat + + + align:start position:0% +movi space time so this is just a flat +R6 metric + + align:start position:0% +R6 metric + + + align:start position:0% +R6 metric +okay and now let's not consider R go to + + align:start position:0% +okay and now let's not consider R go to + + + align:start position:0% +okay and now let's not consider R go to +Infinity just only R much much smaller + + align:start position:0% +Infinity just only R much much smaller + + + align:start position:0% +Infinity just only R much much smaller +than R than this capital r + + align:start position:0% +than R than this capital r + + + align:start position:0% +than R than this capital r +then then this + + align:start position:0% +then then this + + + align:start position:0% +then then this +function so so so again let me call this + + align:start position:0% +function so so so again let me call this + + + align:start position:0% +function so so so again let me call this +F let me call this + + align:start position:0% +F let me call this + + + align:start position:0% +F let me call this +H so for example the the uh did I call + + align:start position:0% +H so for example the the uh did I call + + + align:start position:0% +H so for example the the uh did I call +them H or G yeah uh H yeah yeah so for + + align:start position:0% +them H or G yeah uh H yeah yeah so for + + + align:start position:0% +them H or G yeah uh H yeah yeah so for +example the F the is similar thing with + + align:start position:0% +example the F the is similar thing with + + + align:start position:0% +example the F the is similar thing with +G with h so the F will be one + + align:start position:0% +G with h so the F will be one + + + align:start position:0% +G with h so the F will be one +plus say something of order R to ^ 4 / R + + align:start position:0% +plus say something of order R to ^ 4 / R + + + align:start position:0% +plus say something of order R to ^ 4 / R +to the^ 4 similar + + align:start position:0% +to the^ 4 similar + + + align:start position:0% +to the^ 4 similar +uh with the uh uh + + align:start position:0% +uh with the uh uh + + + align:start position:0% +uh with the uh uh +H so now you + + align:start position:0% +H so now you + + + align:start position:0% +H so now you +recognize that this one / + + align:start position:0% +recognize that this one / + + + align:start position:0% +recognize that this one / +R4 is precisely long + + align:start position:0% + + + + align:start position:0% + +range coolant + + align:start position:0% + + + + align:start position:0% + +potential in in six + + align:start position:0% +potential in in six + + + align:start position:0% +potential in in six +Dimension okay in R six + + align:start position:0% +Dimension okay in R six + + + align:start position:0% +Dimension okay in R six +because the because only transverse + + align:start position:0% +because the because only transverse + + + align:start position:0% +because the because only transverse +Direction + + align:start position:0% +Direction + + + align:start position:0% +Direction +matters and in three spatial Dimension + + align:start position:0% +matters and in three spatial Dimension + + + align:start position:0% +matters and in three spatial Dimension +if you have a point then you have one of + + align:start position:0% +if you have a point then you have one of + + + align:start position:0% +if you have a point then you have one of +R and in six Dimension then you again J + + align:start position:0% +R and in six Dimension then you again J + + + align:start position:0% +R and in six Dimension then you again J +uh you go down two Powers then you get + + align:start position:0% +uh you go down two Powers then you get + + + align:start position:0% +uh you go down two Powers then you get +one over + + align:start position:0% +one over + + + align:start position:0% +one over +R4 so so this Behavior can simply be + + align:start position:0% +R4 so so this Behavior can simply be + + + align:start position:0% +R4 so so this Behavior can simply be +understood say essentially say as you + + align:start position:0% +understood say essentially say as you + + + align:start position:0% +understood say essentially say as you +have some kind of colum + + align:start position:0% +have some kind of colum + + + align:start position:0% +have some kind of colum +potential uh + + align:start position:0% +potential uh + + + align:start position:0% +potential uh +um I both due to the say the conserved + + align:start position:0% +um I both due to the say the conserved + + + align:start position:0% +um I both due to the say the conserved +both due to the uh uh the charge of this + + align:start position:0% +both due to the uh uh the charge of this + + + align:start position:0% +both due to the uh uh the charge of this +part charge of the brain and also due to + + align:start position:0% +part charge of the brain and also due to + + + align:start position:0% +part charge of the brain and also due to +the gravity okay just you have some long + + align:start position:0% +the gravity okay just you have some long + + + align:start position:0% +the gravity okay just you have some long +range + + align:start position:0% + + + + align:start position:0% + +potential so now the interesting + + align:start position:0% +potential so now the interesting + + + align:start position:0% +potential so now the interesting +thing things become more interesting is + + align:start position:0% +thing things become more interesting is + + + align:start position:0% +thing things become more interesting is +when R become of order + + align:start position:0% +when R become of order + + + align:start position:0% +when R become of order +R when R become all R then this + + align:start position:0% +R when R become all R then this + + + align:start position:0% +R when R become all R then this +HR start to be sign different from one + + align:start position:0% +HR start to be sign different from one + + + align:start position:0% +HR start to be sign different from one +okay and then then tells you + + align:start position:0% +okay and then then tells you + + + align:start position:0% +okay and then then tells you +so so this is the uh + + align:start position:0% +so so this is the uh + + + align:start position:0% +so so this is the uh +um when all the what the + + align:start position:0% + + + + align:start position:0% + +differentation Yeah at this range + + align:start position:0% +differentation Yeah at this range + + + align:start position:0% +differentation Yeah at this range +information of SpaceTime + + align:start position:0% + + + + align:start position:0% + +Magic + + align:start position:0% +Magic + + + align:start position:0% +Magic +from + + align:start position:0% +from + + + align:start position:0% +from +this three + + align:start position:0% + + + + align:start position:0% + +brains become + + align:start position:0% + + + + align:start position:0% + +significant okay so in other words this + + align:start position:0% +significant okay so in other words this + + + align:start position:0% +significant okay so in other words this +this capital r this constant essentially + + align:start position:0% +this capital r this constant essentially + + + align:start position:0% +this capital r this constant essentially +signals the distance from the brain + + align:start position:0% +signals the distance from the brain + + + align:start position:0% +signals the distance from the brain +where the uh the gravitational effect or + + align:start position:0% +where the uh the gravitational effect or + + + align:start position:0% +where the uh the gravitational effect or +the become strong okay + + align:start position:0% +the become strong okay + + + align:start position:0% +the become strong okay +the gravitation effect of the deep brain + + align:start position:0% +the gravitation effect of the deep brain + + + align:start position:0% +the gravitation effect of the deep brain +becomes + + align:start position:0% + + + + align:start position:0% + +J and in particular you can check + + align:start position:0% +J and in particular you can check + + + align:start position:0% +J and in particular you can check +yourself you can calculate yourself the + + align:start position:0% +yourself you can calculate yourself the + + + align:start position:0% +yourself you can calculate yourself the +curvature + + align:start position:0% + + + + align:start position:0% + +radius now become of order r or the + + align:start position:0% +radius now become of order r or the + + + align:start position:0% +radius now become of order r or the +curvature itself yeah let me just say + + align:start position:0% +curvature itself yeah let me just say + + + align:start position:0% +curvature itself yeah let me just say +the curvature uh curvature C become R to + + align:start position:0% +the curvature uh curvature C become R to + + + align:start position:0% +the curvature uh curvature C become R to +Theus 4 uh R to Theus + + align:start position:0% +Theus 4 uh R to Theus + + + align:start position:0% +Theus 4 uh R to Theus +2 okay + + align:start position:0% +2 okay + + + align:start position:0% +2 okay +so so essentially the r give you + + align:start position:0% + + + + align:start position:0% + +the say a measure of when the gravity + + align:start position:0% +the say a measure of when the gravity + + + align:start position:0% +the say a measure of when the gravity +becom strong or or or or or or the scale + + align:start position:0% +becom strong or or or or or or the scale + + + align:start position:0% +becom strong or or or or or or the scale +of the + + align:start position:0% + + + + align:start position:0% + +curvature so so we are we solved this + + align:start position:0% +curvature so so we are we solved this + + + align:start position:0% +curvature so so we are we solved this +metric in the context of the superg + + align:start position:0% +metric in the context of the superg + + + align:start position:0% +metric in the context of the superg +gravity in the context of lower + + align:start position:0% +gravity in the context of lower + + + align:start position:0% +gravity in the context of lower +effective the super gravity so so in + + align:start position:0% +effective the super gravity so so in + + + align:start position:0% +effective the super gravity so so in +order for the approximation to works we + + align:start position:0% +order for the approximation to works we + + + align:start position:0% +order for the approximation to works we +said before we wanted the alpha Prime + + align:start position:0% +said before we wanted the alpha Prime + + + align:start position:0% +said before we wanted the alpha Prime +Times the curvature to be much much + + align:start position:0% +Times the curvature to be much much + + + align:start position:0% +Times the curvature to be much much +smaller than one so we said last time so + + align:start position:0% +smaller than one so we said last time so + + + align:start position:0% +smaller than one so we said last time so +so that means we want this to be much + + align:start position:0% +so that means we want this to be much + + + align:start position:0% +so that means we want this to be much +much smaller than + + align:start position:0% +much smaller than + + + align:start position:0% +much smaller than +one so that the super gravity + + align:start position:0% +one so that the super gravity + + + align:start position:0% +one so that the super gravity +approximation can be valed so now if you + + align:start position:0% +approximation can be valed so now if you + + + align:start position:0% +approximation can be valed so now if you +look at the expression of the + + align:start position:0% +look at the expression of the + + + align:start position:0% +look at the expression of the +R so this tells you that the GSM must be + + align:start position:0% +R so this tells you that the GSM must be + + + align:start position:0% +R so this tells you that the GSM must be +much much greater than one + + align:start position:0% + + + + align:start position:0% + +okay yes and must much greater than + + align:start position:0% +okay yes and must much greater than + + + align:start position:0% +okay yes and must much greater than +one and uh and also in order to have the + + align:start position:0% +one and uh and also in order to have the + + + align:start position:0% +one and uh and also in order to have the +string Loop correction to be small we + + align:start position:0% +string Loop correction to be small we + + + align:start position:0% +string Loop correction to be small we +also need GS to be much much smaller + + align:start position:0% +also need GS to be much much smaller + + + align:start position:0% +also need GS to be much much smaller +than one so believe GSN to be much much + + align:start position:0% +than one so believe GSN to be much much + + + align:start position:0% +than one so believe GSN to be much much +greater than one but also GS to much + + align:start position:0% +greater than one but also GS to much + + + align:start position:0% +greater than one but also GS to much +much smaller than one so in order for + + align:start position:0% +much smaller than one so in order for + + + align:start position:0% +much smaller than one so in order for +the um so gravity uh uh + + align:start position:0% +the um so gravity uh uh + + + align:start position:0% +the um so gravity uh uh +um approximation to work + + align:start position:0% + + + + align:start position:0% + +okay so now let's + + align:start position:0% +okay so now let's + + + align:start position:0% +okay so now let's +consider so we set up the the problem so + + align:start position:0% +consider so we set up the the problem so + + + align:start position:0% +consider so we set up the the problem so +this matric is written that I equal to + + align:start position:0% +this matric is written that I equal to + + + align:start position:0% +this matric is written that I equal to +zero is the location of the brain okay I + + align:start position:0% +zero is the location of the brain okay I + + + align:start position:0% +zero is the location of the brain okay I +to Z is location of brain that we uh + + align:start position:0% +to Z is location of brain that we uh + + + align:start position:0% +to Z is location of brain that we uh +when we solve this problem you uh I to Z + + align:start position:0% +when we solve this problem you uh I to Z + + + align:start position:0% +when we solve this problem you uh I to Z +is the presume the location of the brain + + align:start position:0% +is the presume the location of the brain + + + align:start position:0% +is the presume the location of the brain +so now what happens let's see what + + align:start position:0% +so now what happens let's see what + + + align:start position:0% +so now what happens let's see what +happens when we + + align:start position:0% +happens when we + + + align:start position:0% +happens when we +um yeah that's where you put the source + + align:start position:0% +um yeah that's where you put the source + + + align:start position:0% +um yeah that's where you put the source +okay that's where you put the source so + + align:start position:0% +okay that's where you put the source so + + + align:start position:0% +okay that's where you put the source so +now let's consider + + align:start position:0% +now let's consider + + + align:start position:0% +now let's consider +now let's ask the question what + + align:start position:0% + + + + align:start position:0% + +happens to the + + align:start position:0% +happens to the + + + align:start position:0% +happens to the +matric if R goes zero if we try to + + align:start position:0% +matric if R goes zero if we try to + + + align:start position:0% +matric if R goes zero if we try to +approach the brain okay okay if we try + + align:start position:0% +approach the brain okay okay if we try + + + align:start position:0% +approach the brain okay okay if we try +to approach + + align:start position:0% +to approach + + + align:start position:0% +to approach +brain so so this this is very easy to do + + align:start position:0% +brain so so this this is very easy to do + + + align:start position:0% +brain so so this this is very easy to do +so when R become much smaller than R to + + align:start position:0% +so when R become much smaller than R to + + + align:start position:0% +so when R become much smaller than R to +the capital r when R goes to + + align:start position:0% +the capital r when R goes to + + + align:start position:0% +the capital r when R goes to +zero then in this expression this term + + align:start position:0% +zero then in this expression this term + + + align:start position:0% +zero then in this expression this term +will dominate + + align:start position:0% +will dominate + + + align:start position:0% +will dominate +okay we can forget about one this term + + align:start position:0% +okay we can forget about one this term + + + align:start position:0% +okay we can forget about one this term +will dominate so so in this case the H + + align:start position:0% +will dominate so so in this case the H + + + align:start position:0% +will dominate so so in this case the H +will be will be given by R to the 4 + + align:start position:0% +will be will be given by R to the 4 + + + align:start position:0% +will be will be given by R to the 4 +R4 okay then you just plug this into the + + align:start position:0% +R4 okay then you just plug this into the + + + align:start position:0% +R4 okay then you just plug this into the +your original + + align:start position:0% +your original + + + align:start position:0% +your original +matric okay so you plug this + + align:start position:0% + + + + align:start position:0% + +back so when you plug this + + align:start position:0% +back so when you plug this + + + align:start position:0% +back so when you plug this +back so so H is equal to so H minus 12 + + align:start position:0% +back so so H is equal to so H minus 12 + + + align:start position:0% +back so so H is equal to so H minus 12 +then just become r s / r s then we still + + align:start position:0% +then just become r s / r s then we still + + + align:start position:0% +then just become r s / r s then we still +have DT s + DX + + align:start position:0% +have DT s + DX + + + align:start position:0% +have DT s + DX +s then plus + + align:start position:0% +s then plus + + + align:start position:0% +s then plus +r² r s so that's is positive + + align:start position:0% +r² r s so that's is positive + + + align:start position:0% +r² r s so that's is positive +12 then the r² + r² the OM 5 + + align:start position:0% +12 then the r² + r² the OM 5 + + + align:start position:0% +12 then the r² + r² the OM 5 +S + + align:start position:0% + + + + align:start position:0% + +okay but now something miraculous + + align:start position:0% +okay but now something miraculous + + + align:start position:0% +okay but now something miraculous +happened something miraculous happened + + align:start position:0% +happened something miraculous happened + + + align:start position:0% +happened something miraculous happened +so let me slightly write this matric in + + align:start position:0% +so let me slightly write this matric in + + + align:start position:0% +so let me slightly write this matric in +the slightly more explicit way and I + + align:start position:0% +the slightly more explicit way and I + + + align:start position:0% +the slightly more explicit way and I +write + + align:start position:0% + + + + align:start position:0% + +it so let me just separate these two + + align:start position:0% + + + + align:start position:0% + +terms + + align:start position:0% +terms + + + align:start position:0% +terms +okay so there two important thing + + align:start position:0% +okay so there two important thing + + + align:start position:0% +okay so there two important thing +happens the two important thing happens + + align:start position:0% +happens the two important thing happens + + + align:start position:0% +happens the two important thing happens +just to give you a + + align:start position:0% +just to give you a + + + align:start position:0% +just to give you a +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +um uh um yeah let me just do it + + align:start position:0% +um uh um yeah let me just do it + + + align:start position:0% +um uh um yeah let me just do it +here yeah let me do it here maybe it's + + align:start position:0% +here yeah let me do it here maybe it's + + + align:start position:0% +here yeah let me do it here maybe it's +good enough maybe be good just safe so + + align:start position:0% +good enough maybe be good just safe so + + + align:start position:0% +good enough maybe be good just safe so +previously let's just draw the plot like + + align:start position:0% +previously let's just draw the plot like + + + align:start position:0% +previously let's just draw the plot like +this so let's call this R six okay just + + align:start position:0% +this so let's call this R six okay just + + + align:start position:0% +this so let's call this R six okay just +for my + + align:start position:0% +for my + + + align:start position:0% +for my +purpose yeah let's consider uh uh this + + align:start position:0% +purpose yeah let's consider uh uh this + + + align:start position:0% +purpose yeah let's consider uh uh this +is the r + + align:start position:0% + + + + align:start position:0% + +six and uh yeah forget about what's + + align:start position:0% +six and uh yeah forget about what's + + + align:start position:0% +six and uh yeah forget about what's +outside it just imagine the + + align:start position:0% +outside it just imagine the + + + align:start position:0% +outside it just imagine the +yeah there's no outside just the whole + + align:start position:0% +yeah there's no outside just the whole + + + align:start position:0% +yeah there's no outside just the whole +thing is R six okay and when we start + + align:start position:0% +thing is R six okay and when we start + + + align:start position:0% +thing is R six okay and when we start +solving this problem that this rein this + + align:start position:0% +solving this problem that this rein this + + + align:start position:0% +solving this problem that this rein this +rein are point in this R six and then + + align:start position:0% +rein are point in this R six and then + + + align:start position:0% +rein are point in this R six and then +there's some flux coming out of + + align:start position:0% +there's some flux coming out of + + + align:start position:0% +there's some flux coming out of +it okay there's some F5 flux coming out + + align:start position:0% +it okay there's some F5 flux coming out + + + align:start position:0% +it okay there's some F5 flux coming out +of it uh so this is the picture the flux + + align:start position:0% +of it uh so this is the picture the flux + + + align:start position:0% +of it uh so this is the picture the flux +is normal to the F6 H the flux is normal + + align:start position:0% +is normal to the F6 H the flux is normal + + + align:start position:0% +is normal to the F6 H the flux is normal +to F to R6 or no the flux is normal to + + align:start position:0% +to F to R6 or no the flux is normal to + + + align:start position:0% +to F to R6 or no the flux is normal to +the S5 surrounding the + + align:start position:0% +the S5 surrounding the + + + align:start position:0% +the S5 surrounding the +point and just like that I'm just saying + + align:start position:0% +point and just like that I'm just saying + + + align:start position:0% +point and just like that I'm just saying +think about the plane is a whole R six + + align:start position:0% +think about the plane is a whole R six + + + align:start position:0% +think about the plane is a whole R six +uhhuh uh uh uh there's nothing outside + + align:start position:0% +uhhuh uh uh uh there's nothing outside + + + align:start position:0% +uhhuh uh uh uh there's nothing outside +the plane okay okay I want to reserve + + align:start position:0% +the plane okay okay I want to reserve + + + align:start position:0% +the plane okay okay I want to reserve +the things outside plane for other + + align:start position:0% +the things outside plane for other + + + align:start position:0% +the things outside plane for other +purpose I just now think about R is the + + align:start position:0% +purpose I just now think about R is the + + + align:start position:0% +purpose I just now think about R is the +whole thing this is your whole + + align:start position:0% +whole thing this is your whole + + + align:start position:0% +whole thing this is your whole +Space okay so so if you look at this + + align:start position:0% +Space okay so so if you look at this + + + align:start position:0% +Space okay so so if you look at this +situation there are two in there two + + align:start position:0% +situation there are two in there two + + + align:start position:0% +situation there are two in there two +things first there's a source at I equal + + align:start position:0% +things first there's a source at I equal + + + align:start position:0% +things first there's a source at I equal +to + + align:start position:0% +to + + + align:start position:0% +to +zero you should see you see see a data + + align:start position:0% +zero you should see you see see a data + + + align:start position:0% +zero you should see you see see a data +function which is the source of the flux + + align:start position:0% +function which is the source of the flux + + + align:start position:0% +function which is the source of the flux +and this the source of the mass okay + + align:start position:0% +and this the source of the mass okay + + + align:start position:0% +and this the source of the mass okay +there's some tension there and another + + align:start position:0% +there's some tension there and another + + + align:start position:0% +there's some tension there and another +thing is that if you look at + + align:start position:0% +thing is that if you look at + + + align:start position:0% +thing is that if you look at +S5 around this point and this five when + + align:start position:0% +S5 around this point and this five when + + + align:start position:0% +S5 around this point and this five when +you go to the point then S5 will become + + align:start position:0% +you go to the point then S5 will become + + + align:start position:0% +you go to the point then S5 will become +zero sides okay so around this + + align:start position:0% +zero sides okay so around this + + + align:start position:0% +zero sides okay so around this +point yeah just in flat space around the + + align:start position:0% +point yeah just in flat space around the + + + align:start position:0% +point yeah just in flat space around the +uh uh you have if you write in the polar + + align:start position:0% +uh uh you have if you write in the polar + + + align:start position:0% +uh uh you have if you write in the polar +coordinate so the Sid of this S5 + + align:start position:0% +coordinate so the Sid of this S5 + + + align:start position:0% +coordinate so the Sid of this S5 +surrounding this point become zero sides + + align:start position:0% +surrounding this point become zero sides + + + align:start position:0% +surrounding this point become zero sides +when you go to that point okay + + align:start position:0% +when you go to that point okay + + + align:start position:0% +when you go to that point okay +uh uh uh uh uh + + align:start position:0% +uh uh uh uh uh + + + align:start position:0% +uh uh uh uh uh +yeah but now if you look at this + + align:start position:0% + + + + align:start position:0% + +matric now if you look at this + + align:start position:0% +matric now if you look at this + + + align:start position:0% +matric now if you look at this +metric now actually when you go to the + + align:start position:0% +metric now actually when you go to the + + + align:start position:0% +metric now actually when you go to the +when you go to the brain location of the + + align:start position:0% +when you go to the brain location of the + + + align:start position:0% +when you go to the brain location of the +brain actually level reach I equal to + + align:start position:0% +brain actually level reach I equal to + + + align:start position:0% +brain actually level reach I equal to +zero actually this S5 now become a + + align:start position:0% +zero actually this S5 now become a + + + align:start position:0% +zero actually this S5 now become a +constant sides okay and also now if you + + align:start position:0% +constant sides okay and also now if you + + + align:start position:0% +constant sides okay and also now if you +can look at this so there are two things + + align:start position:0% +can look at this so there are two things + + + align:start position:0% +can look at this so there are two things +is happening so first this is one this + + align:start position:0% +is happening so first this is one this + + + align:start position:0% +is happening so first this is one this +is two so the first + + align:start position:0% +is two so the first + + + align:start position:0% +is two so the first +thing is said S5 + + align:start position:0% +thing is said S5 + + + align:start position:0% +thing is said S5 +direction S5 let me call + + align:start position:0% + + + + align:start position:0% + +S5 now has a constant + + align:start position:0% + + + + align:start position:0% + +radius given by this R so this is first + + align:start position:0% +radius given by this R so this is first + + + align:start position:0% +radius given by this R so this is first +thing and the second + + align:start position:0% +thing and the second + + + align:start position:0% +thing and the second +thing is that because of this Dr R + + align:start position:0% +thing is that because of this Dr R + + + align:start position:0% +thing is that because of this Dr R +square over R square + + align:start position:0% +square over R square + + + align:start position:0% +square over R square +structure so if you write as a proper + + align:start position:0% +structure so if you write as a proper + + + align:start position:0% +structure so if you write as a proper +distance write it as DL squ so DL will + + align:start position:0% +distance write it as DL squ so DL will + + + align:start position:0% +distance write it as DL squ so DL will +be the proper + + align:start position:0% +be the proper + + + align:start position:0% +be the proper +distance then you when you solve this + + align:start position:0% +distance then you when you solve this + + + align:start position:0% +distance then you when you solve this +then you find L is essentially log R say + + align:start position:0% +then you find L is essentially log R say + + + align:start position:0% +then you find L is essentially log R say +plus some + + align:start position:0% + + + + align:start position:0% + +constant then as R goes to zero the L + + align:start position:0% +constant then as R goes to zero the L + + + align:start position:0% +constant then as R goes to zero the L +goes to when R goes to zero the L goes + + align:start position:0% +goes to when R goes to zero the L goes + + + align:start position:0% +goes to when R goes to zero the L goes +to minus + + align:start position:0% + + + + align:start position:0% + +Infinity that means that I equal to + + align:start position:0% +Infinity that means that I equal to + + + align:start position:0% +Infinity that means that I equal to +zero yeah let me just write it here this + + align:start position:0% +zero yeah let me just write it here this + + + align:start position:0% +zero yeah let me just write it here this +means IAL to + + align:start position:0% + + + + align:start position:0% + +zero + + align:start position:0% +zero + + + align:start position:0% +zero +sit at infinite proper distance + + align:start position:0% + + + + align:start position:0% + +away + + align:start position:0% + + + + align:start position:0% + +okay so for all practical purpose the + + align:start position:0% +okay so for all practical purpose the + + + align:start position:0% +okay so for all practical purpose the +brain has + + align:start position:0% +brain has + + + align:start position:0% +brain has +disappeared okay so so the geometric + + align:start position:0% +disappeared okay so so the geometric + + + align:start position:0% +disappeared okay so so the geometric +picture is that when you include this uh + + align:start position:0% +picture is that when you include this uh + + + align:start position:0% +picture is that when you include this uh +the uh when you include the gravity of + + align:start position:0% +the uh when you include the gravity of + + + align:start position:0% +the uh when you include the gravity of +this + + align:start position:0% + + + + align:start position:0% + +source so now I have to draw something + + align:start position:0% +source so now I have to draw something + + + align:start position:0% +source so now I have to draw something +called the embedding diagram just use + + align:start position:0% +called the embedding diagram just use + + + align:start position:0% +called the embedding diagram just use +the this actual direction to show the + + align:start position:0% +the this actual direction to show the + + + align:start position:0% +the this actual direction to show the +curvature okay so so when you go when + + align:start position:0% +curvature okay so so when you go when + + + align:start position:0% +curvature okay so so when you go when +you approach this point what do you find + + align:start position:0% +you approach this point what do you find + + + align:start position:0% +you approach this point what do you find +you don't find the point actually you + + align:start position:0% +you don't find the point actually you + + + align:start position:0% +you don't find the point actually you +find this infinite + + align:start position:0% + + + + align:start position:0% + +throat and so when you try to go + + align:start position:0% +throat and so when you try to go + + + align:start position:0% +throat and so when you try to go +approach this point and this is this is + + align:start position:0% +approach this point and this is this is + + + align:start position:0% +approach this point and this is this is +the cross-section of this + + align:start position:0% +the cross-section of this + + + align:start position:0% +the cross-section of this +throat which I can not draw is + + align:start position:0% +throat which I can not draw is + + + align:start position:0% +throat which I can not draw is +S5 with a constant + + align:start position:0% +S5 with a constant + + + align:start position:0% +S5 with a constant +radius and uh and then this SLO has + + align:start position:0% +radius and uh and then this SLO has + + + align:start position:0% +radius and uh and then this SLO has +infinite non distance + + align:start position:0% +infinite non distance + + + align:start position:0% +infinite non distance +okay so it's l and and and here and and + + align:start position:0% +okay so it's l and and and here and and + + + align:start position:0% +okay so it's l and and and here and and +and have a infinite + + align:start position:0% +and have a infinite + + + align:start position:0% +and have a infinite +distance + + align:start position:0% + + + + align:start position:0% + +okay so uh uh so that's what's happening + + align:start position:0% +okay so uh uh so that's what's happening + + + align:start position:0% +okay so uh uh so that's what's happening +here and yeah the size of this sphere of + + align:start position:0% +here and yeah the size of this sphere of + + + align:start position:0% +here and yeah the size of this sphere of +course is R of radius + + align:start position:0% +course is R of radius + + + align:start position:0% +course is R of radius +R of radius + + align:start position:0% +R of radius + + + align:start position:0% +R of radius +r + + align:start position:0% + + + + align:start position:0% + +so in this + + align:start position:0% +so in this + + + align:start position:0% +so in this +picture so when you include the uh the + + align:start position:0% +picture so when you include the uh the + + + align:start position:0% +picture so when you include the uh the +say what we say the back reaction of the + + align:start position:0% +say what we say the back reaction of the + + + align:start position:0% +say what we say the back reaction of the +dis rant essentially the dis rant + + align:start position:0% +dis rant essentially the dis rant + + + align:start position:0% +dis rant essentially the dis rant +themselves have disappeared the only + + align:start position:0% +themselves have disappeared the only + + + align:start position:0% +themselves have disappeared the only +thing + + align:start position:0% +thing + + + align:start position:0% +thing +left uh are this curved geometry and the + + align:start position:0% +left uh are this curved geometry and the + + + align:start position:0% +left uh are this curved geometry and the +fluxes yeah they still uh uh the fluxes + + align:start position:0% +fluxes yeah they still uh uh the fluxes + + + align:start position:0% +fluxes yeah they still uh uh the fluxes +won't go away so you will still see the + + align:start position:0% +won't go away so you will still see the + + + align:start position:0% +won't go away so you will still see the +the S5 flux the F5 the F5 flock through + + align:start position:0% +the S5 flux the F5 the F5 flock through + + + align:start position:0% +the S5 flux the F5 the F5 flock through +this S5 okay so there still flock + + align:start position:0% +this S5 okay so there still flock + + + align:start position:0% +this S5 okay so there still flock +through this + + align:start position:0% + + + + align:start position:0% + +S5 + + align:start position:0% +S5 + + + align:start position:0% +S5 +okay and this matric so this is S5 which + + align:start position:0% +okay and this matric so this is S5 which + + + align:start position:0% +okay and this matric so this is S5 which +completely decoupled from the rest part + + align:start position:0% +completely decoupled from the rest part + + + align:start position:0% +completely decoupled from the rest part +so this have a constant radius so this + + align:start position:0% +so this have a constant radius so this + + + align:start position:0% +so this have a constant radius so this +S5 have decoupled from the rest part so + + align:start position:0% +S5 have decoupled from the rest part so + + + align:start position:0% +S5 have decoupled from the rest part so +it's natur just look at this part and + + align:start position:0% +it's natur just look at this part and + + + align:start position:0% +it's natur just look at this part and +this is actually + + align:start position:0% +this is actually + + + align:start position:0% +this is actually +ads5 so so so uh so let me call one so + + align:start position:0% + + + + align:start position:0% + +one is just a this is the matric of five + + align:start position:0% +one is just a this is the matric of five + + + align:start position:0% +one is just a this is the matric of five +dimensional and space time and times + + align:start position:0% +dimensional and space time and times + + + align:start position:0% +dimensional and space time and times +S5 okay and at S5 uh have the + + align:start position:0% +S5 okay and at S5 uh have the + + + align:start position:0% +S5 okay and at S5 uh have the +matric so let me just copy here + + align:start position:0% +matric so let me just copy here + + + align:start position:0% +matric so let me just copy here +essentially just this part r² Rus DT s+ + + align:start position:0% +essentially just this part r² Rus DT s+ + + + align:start position:0% +essentially just this part r² Rus DT s+ +D + + align:start position:0% +D + + + align:start position:0% +D +x² + + align:start position:0% +x² + + + align:start position:0% +x² +plus r² r² r s okay so this is ADS + + align:start position:0% + + + + align:start position:0% + + + align:start position:0% + + + align:start position:0% +so Something Magic has + + align:start position:0% +so Something Magic has + + + align:start position:0% +so Something Magic has +happened when you try to reach the brain + + align:start position:0% +happened when you try to reach the brain + + + align:start position:0% +happened when you try to reach the brain +then you find the brain is no longer + + align:start position:0% +then you find the brain is no longer + + + align:start position:0% +then you find the brain is no longer +there and actually develop a infinite + + align:start position:0% +there and actually develop a infinite + + + align:start position:0% +there and actually develop a infinite +throat and this Thro the Matrix given by + + align:start position:0% +throat and this Thro the Matrix given by + + + align:start position:0% +throat and this Thro the Matrix given by +S5 * S5 okay of course at Infinity you + + align:start position:0% +S5 * S5 okay of course at Infinity you + + + align:start position:0% +S5 * S5 okay of course at Infinity you +still see a flat space + + align:start position:0% +still see a flat space + + + align:start position:0% +still see a flat space +SP and infinity still see FL movy + + align:start position:0% +SP and infinity still see FL movy + + + align:start position:0% +SP and infinity still see FL movy +space + + align:start position:0% + + + + align:start position:0% + +okay so now we have to take a little bit + + align:start position:0% +okay so now we have to take a little bit + + + align:start position:0% +okay so now we have to take a little bit +conceptual + + align:start position:0% + + + + align:start position:0% + +deap so now we have to take a little bit + + align:start position:0% +deap so now we have to take a little bit + + + align:start position:0% +deap so now we have to take a little bit +conceptual deap yes so we just basically + + align:start position:0% +conceptual deap yes so we just basically + + + align:start position:0% +conceptual deap yes so we just basically +found the most General uh solution of gr + + align:start position:0% +found the most General uh solution of gr + + + align:start position:0% +found the most General uh solution of gr +with the given symmetries given by the r + + align:start position:0% +with the given symmetries given by the r + + + align:start position:0% +with the given symmetries given by the r +yeah with uh what do we mean by most + + align:start position:0% +yeah with uh what do we mean by most + + + align:start position:0% +yeah with uh what do we mean by most +General we have a specific D3 brains + + align:start position:0% +General we have a specific D3 brains + + + align:start position:0% +General we have a specific D3 brains +well so we we fixed the Symmetry given + + align:start position:0% +well so we we fixed the Symmetry given + + + align:start position:0% +well so we we fixed the Symmetry given +by the D3 brain and then no you also fix + + align:start position:0% +by the D3 brain and then no you also fix + + + align:start position:0% +by the D3 brain and then no you also fix +the this rant charge and this rent + + align:start position:0% +the this rant charge and this rent + + + align:start position:0% +the this rant charge and this rent +tension okay no that you Lally fix + + align:start position:0% +tension okay no that you Lally fix + + + align:start position:0% +tension okay no that you Lally fix +everything okay yeah yes so what is the + + align:start position:0% +everything okay yeah yes so what is the + + + align:start position:0% +everything okay yeah yes so what is the +nature of the source originally in this + + align:start position:0% +nature of the source originally in this + + + align:start position:0% +nature of the source originally in this +is like a + + align:start position:0% +is like a + + + align:start position:0% +is like a +electromagnetic but now it's like a + + align:start position:0% +electromagnetic but now it's like a + + + align:start position:0% +electromagnetic but now it's like a +mass no not the mass even the mass is + + align:start position:0% +mass no not the mass even the mass is + + + align:start position:0% +mass no not the mass even the mass is +gone you only see a curved space time uh + + align:start position:0% +gone you only see a curved space time uh + + + align:start position:0% +gone you only see a curved space time uh +uh curved space time and with some + + align:start position:0% +uh curved space time and with some + + + align:start position:0% +uh curved space time and with some +fluxes I mean + + align:start position:0% +fluxes I mean + + + align:start position:0% +fluxes I mean +that c + + align:start position:0% +that c + + + align:start position:0% +that c +c re for the mass yeah but the mass now + + align:start position:0% +c re for the mass yeah but the mass now + + + align:start position:0% +c re for the mass yeah but the mass now +is completely gone it's sitting it's in + + align:start position:0% +is completely gone it's sitting it's in + + + align:start position:0% +is completely gone it's sitting it's in +some sense sitting at infinite distance + + align:start position:0% +some sense sitting at infinite distance + + + align:start position:0% +some sense sitting at infinite distance +away you can never reach it and uh and + + align:start position:0% +away you can never reach it and uh and + + + align:start position:0% +away you can never reach it and uh and +for all practical purpose if you leave + + align:start position:0% +for all practical purpose if you leave + + + align:start position:0% +for all practical purpose if you leave +this space time you will never see the + + align:start position:0% +this space time you will never see the + + + align:start position:0% +this space time you will never see the +source what you will see what you will + + align:start position:0% +source what you will see what you will + + + align:start position:0% +source what you will see what you will +observe is just a curve space time with + + align:start position:0% +observe is just a curve space time with + + + align:start position:0% +observe is just a curve space time with +some + + align:start position:0% +some + + + align:start position:0% +some +fluxes and uh and these are also perfect + + align:start position:0% +fluxes and uh and these are also perfect + + + align:start position:0% +fluxes and uh and these are also perfect +solution of the Einstein equation yeah + + align:start position:0% +solution of the Einstein equation yeah + + + align:start position:0% +solution of the Einstein equation yeah +because away from the source it's also + + align:start position:0% +because away from the source it's also + + + align:start position:0% +because away from the source it's also +perfect solution of Einstein equations + + align:start position:0% +perfect solution of Einstein equations + + + align:start position:0% +perfect solution of Einstein equations +yeah yeah you have first yeah yeah so I + + align:start position:0% +yeah yeah you have first yeah yeah so I + + + align:start position:0% +yeah yeah you have first yeah yeah so I +was just so I was just trying to + + align:start position:0% +was just so I was just trying to + + + align:start position:0% +was just so I was just trying to +understand so the point is that so is + + align:start position:0% +understand so the point is that so is + + + align:start position:0% +understand so the point is that so is +this somehow like protecting us from + + align:start position:0% +this somehow like protecting us from + + + align:start position:0% +this somehow like protecting us from +these issues that I mean even + + align:start position:0% +these issues that I mean even + + + align:start position:0% +these issues that I mean even +electromagnetism or even Quantum these + + align:start position:0% +electromagnetism or even Quantum these + + + align:start position:0% +electromagnetism or even Quantum these +issues of like the Divergence of kind of + + align:start position:0% +issues of like the Divergence of kind of + + + align:start position:0% +issues of like the Divergence of kind of +going towards a point charge so this is + + align:start position:0% +going towards a point charge so this is + + + align:start position:0% +going towards a point charge so this is +this somehow like getting around that by + + align:start position:0% +this somehow like getting around that by + + + align:start position:0% +this somehow like getting around that by +like making it you know go far away or + + align:start position:0% +like making it you know go far away or + + + align:start position:0% +like making it you know go far away or +not really yeah no this is not getting + + align:start position:0% +not really yeah no this is not getting + + + align:start position:0% +not really yeah no this is not getting +around that this is + + align:start position:0% +around that this is + + + align:start position:0% +around that this is +the solution present + + align:start position:0% +the solution present + + + align:start position:0% +the solution present +itself no we did not dictate this + + align:start position:0% +itself no we did not dictate this + + + align:start position:0% +itself no we did not dictate this +solution this is a pure + + align:start position:0% +solution this is a pure + + + align:start position:0% +solution this is a pure +mathematics and we just trying to + + align:start position:0% +mathematics and we just trying to + + + align:start position:0% +mathematics and we just trying to +interpret this uh mathematics right but + + align:start position:0% +interpret this uh mathematics right but + + + align:start position:0% +interpret this uh mathematics right but +I'm saying but but it does achieve that + + align:start position:0% +I'm saying but but it does achieve that + + + align:start position:0% +I'm saying but but it does achieve that +I mean we for right right yeah just the + + align:start position:0% +I mean we for right right yeah just the + + + align:start position:0% +I mean we for right right yeah just the +solution present itself that's crazy + + align:start position:0% +solution present itself that's crazy + + + align:start position:0% +solution present itself that's crazy +okay yeah + + align:start position:0% + + + + align:start position:0% + +yes + + align:start position:0% +yes + + + align:start position:0% +yes +wouldn't space like this but D well what + + align:start position:0% +wouldn't space like this but D well what + + + align:start position:0% +wouldn't space like this but D well what +about + + align:start position:0% +about + + + align:start position:0% +about +other like yeah yeah that's something + + align:start position:0% +other like yeah yeah that's something + + + align:start position:0% +other like yeah yeah that's something +similar will happen but the story is + + align:start position:0% +similar will happen but the story is + + + align:start position:0% +similar will happen but the story is +even more complicated yeah so the this + + align:start position:0% +even more complicated yeah so the this + + + align:start position:0% +even more complicated yeah so the this +re brain the matric is + + align:start position:0% +re brain the matric is + + + align:start position:0% +re brain the matric is +simplest yeah for reasons I will mention + + align:start position:0% +simplest yeah for reasons I will mention + + + align:start position:0% +simplest yeah for reasons I will mention +later yeah yeah so the reason I choose + + align:start position:0% +later yeah yeah so the reason I choose + + + align:start position:0% +later yeah yeah so the reason I choose +this Reb brain just because the the + + align:start position:0% +this Reb brain just because the the + + + align:start position:0% +this Reb brain just because the the +matric is a simp is + + align:start position:0% + + + + align:start position:0% + +one other + + align:start position:0% +one other + + + align:start position:0% +one other +questions so the longterm long range + + align:start position:0% +questions so the longterm long range + + + align:start position:0% +questions so the longterm long range +cooling potential that's from the charge + + align:start position:0% +cooling potential that's from the charge + + + align:start position:0% +cooling potential that's from the charge +of the brain both okay you can't really + + align:start position:0% +of the brain both okay you can't really + + + align:start position:0% +of the brain both okay you can't really +separate yeah in principle you can + + align:start position:0% +separate yeah in principle you can + + + align:start position:0% +separate yeah in principle you can +separate depend on your probe yeah but + + align:start position:0% +separate depend on your probe yeah but + + + align:start position:0% +separate depend on your probe yeah but +from the metric from the metric from the + + align:start position:0% +from the metric from the metric from the + + + align:start position:0% +from the metric from the metric from the +metric actually from the matric it just + + align:start position:0% +metric actually from the matric it just + + + align:start position:0% +metric actually from the matric it just +from the in some sense it come from the + + align:start position:0% +from the in some sense it come from the + + + align:start position:0% +from the in some sense it come from the +um uh uh + + align:start position:0% +um uh uh + + + align:start position:0% +um uh uh +it's from matric of course you should + + align:start position:0% +it's from matric of course you should + + + align:start position:0% +it's from matric of course you should +just interpret as a gravitational part + + align:start position:0% +just interpret as a gravitational part + + + align:start position:0% +just interpret as a gravitational part +yeah this is just gravitational part + + align:start position:0% +yeah this is just gravitational part + + + align:start position:0% +yeah this is just gravitational part +question so there you draw the flu + + align:start position:0% +question so there you draw the flu + + + align:start position:0% +question so there you draw the flu +flowing out of the cylinder or alone the + + align:start position:0% +flowing out of the cylinder or alone the + + + align:start position:0% +flowing out of the cylinder or alone the +cylinder I guess it's alone Cinder no no + + align:start position:0% +cylinder I guess it's alone Cinder no no + + + align:start position:0% +cylinder I guess it's alone Cinder no no +no not alone the cylinder alone the + + align:start position:0% +no not alone the cylinder alone the + + + align:start position:0% +no not alone the cylinder alone the +cinder is the R Direction yeah the flux + + align:start position:0% +cinder is the R Direction yeah the flux + + + align:start position:0% +cinder is the R Direction yeah the flux +is the flux is in the S5 it's just think + + align:start position:0% +is the flux is in the S5 it's just think + + + align:start position:0% +is the flux is in the S5 it's just think +of a hollow + + align:start position:0% +of a hollow + + + align:start position:0% +of a hollow +S2 think of a h Square think of a h S2 + + align:start position:0% +S2 think of a h Square think of a h S2 + + + align:start position:0% +S2 think of a h Square think of a h S2 +then on S2 you can have magnetic flux + + align:start position:0% +then on S2 you can have magnetic flux + + + align:start position:0% +then on S2 you can have magnetic flux +and flex is along the radial Direction + + align:start position:0% +and flex is along the radial Direction + + + align:start position:0% +and flex is along the radial Direction +no no there's no radial direction if you + + align:start position:0% +no no there's no radial direction if you + + + align:start position:0% +no no there's no radial direction if you +only have S2 then there's no radial + + align:start position:0% +only have S2 then there's no radial + + + align:start position:0% +only have S2 then there's no radial +Direction just only have S2 okay and + + align:start position:0% +Direction just only have S2 okay and + + + align:start position:0% +Direction just only have S2 okay and +then you can have a flux on that S2 yes + + align:start position:0% +then you can have a flux on that S2 yes + + + align:start position:0% +then you can have a flux on that S2 yes +yeah something proportional to F Theta 5 + + align:start position:0% +yeah something proportional to F Theta 5 + + + align:start position:0% +yeah something proportional to F Theta 5 +say in electromagnetism yeah so this + + align:start position:0% +say in electromagnetism yeah so this + + + align:start position:0% +say in electromagnetism yeah so this +would be a magnetic flux in the yeah yes + + align:start position:0% +would be a magnetic flux in the yeah yes + + + align:start position:0% +would be a magnetic flux in the yeah yes +so write in s uh oh oh yes but but you + + align:start position:0% +so write in s uh oh oh yes but but you + + + align:start position:0% +so write in s uh oh oh yes but but you +write it like in R six if you're writing + + align:start position:0% +write it like in R six if you're writing + + + align:start position:0% +write it like in R six if you're writing +in R six it is along the radius + + align:start position:0% +in R six it is along the radius + + + align:start position:0% +in R six it is along the radius +Direction uh yeah just forget about the + + align:start position:0% +Direction uh yeah just forget about the + + + align:start position:0% +Direction uh yeah just forget about the +uh in this + + align:start position:0% +uh in this + + + align:start position:0% +uh in this +picture is like in the uh in the in the + + align:start position:0% +picture is like in the uh in the in the + + + align:start position:0% +picture is like in the uh in the in the +radio Direction + + align:start position:0% +radio Direction + + + align:start position:0% +radio Direction +but once in this picture and then this + + align:start position:0% +but once in this picture and then this + + + align:start position:0% +but once in this picture and then this +become completely decoupled and and then + + align:start position:0% +become completely decoupled and and then + + + align:start position:0% +become completely decoupled and and then +just you just have separate S5 + + align:start position:0% +just you just have separate S5 + + + align:start position:0% +just you just have separate S5 +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +yeah okay so now we have to do a little + + align:start position:0% +yeah okay so now we have to do a little + + + align:start position:0% +yeah okay so now we have to do a little +bit conceptual deap it's not too big is + + align:start position:0% +bit conceptual deap it's not too big is + + + align:start position:0% +bit conceptual deap it's not too big is +said now we have + + align:start position:0% + + + + align:start position:0% + +two + + align:start position:0% + + + + align:start position:0% + +of this three + + align:start position:0% + + + + align:start position:0% + +brains okay so in the description + + align:start position:0% +brains okay so in the description + + + align:start position:0% +brains okay so in the description +one you just have a deep brain you + + align:start position:0% +one you just have a deep brain you + + + align:start position:0% +one you just have a deep brain you +really just have some dly boundary + + align:start position:0% +really just have some dly boundary + + + align:start position:0% +really just have some dly boundary +conditions in + + align:start position:0% +conditions in + + + align:start position:0% +conditions in +flat same in corsky 10 dimensional space + + align:start position:0% +flat same in corsky 10 dimensional space + + + align:start position:0% +flat same in corsky 10 dimensional space +time and where open strings can end + + align:start position:0% +time and where open strings can end + + + align:start position:0% +time and where open strings can end +where open strings leave + + align:start position:0% + + + + align:start position:0% + +say so in this picture you just you + + align:start position:0% +say so in this picture you just you + + + align:start position:0% +say so in this picture you just you +specify some + + align:start position:0% + + + + align:start position:0% + +plane some some some surface in the + + align:start position:0% +plane some some some surface in the + + + align:start position:0% +plane some some some surface in the +minkovski 10 + + align:start position:0% +minkovski 10 + + + align:start position:0% +minkovski 10 +Dimension and uh and so this is R1 R3 + + align:start position:0% +Dimension and uh and so this is R1 R3 + + + align:start position:0% +Dimension and uh and so this is R1 R3 +say or1 comma 3 if you include the time + + align:start position:0% +say or1 comma 3 if you include the time + + + align:start position:0% +say or1 comma 3 if you include the time +Direction so include so you just specify + + align:start position:0% +Direction so include so you just specify + + + align:start position:0% +Direction so include so you just specify +some plane in the space time in the 10 + + align:start position:0% +some plane in the space time in the 10 + + + align:start position:0% +some plane in the space time in the 10 +SP time where on this plane you can have + + align:start position:0% +SP time where on this plane you can have + + + align:start position:0% +SP time where on this plane you can have +open string + + align:start position:0% +open string + + + align:start position:0% +open string +excitations + + align:start position:0% +excitations + + + align:start position:0% +excitations +okay and then this the system of course + + align:start position:0% +okay and then this the system of course + + + align:start position:0% +okay and then this the system of course +can also have close + + align:start position:0% +can also have close + + + align:start position:0% +can also have close +strings then this close string can + + align:start position:0% +strings then this close string can + + + align:start position:0% +strings then this close string can +interact with the brain can interact + + align:start position:0% +interact with the brain can interact + + + align:start position:0% +interact with the brain can interact +with the open strings Etc and uh and uh + + align:start position:0% +with the open strings Etc and uh and uh + + + align:start position:0% +with the open strings Etc and uh and uh +uh uh the + + align:start position:0% +uh uh the + + + align:start position:0% +uh uh the +only so everything is in the flat space + + align:start position:0% +only so everything is in the flat space + + + align:start position:0% +only so everything is in the flat space +everything is in the flat space and uh + + align:start position:0% +everything is in the flat space and uh + + + align:start position:0% +everything is in the flat space and uh +and uh uh uh uh you have open string you + + align:start position:0% +and uh uh uh uh you have open string you + + + align:start position:0% +and uh uh uh uh you have open string you +have closed string open string leave on + + align:start position:0% +have closed string open string leave on + + + align:start position:0% +have closed string open string leave on +the brain the Clos string can attct with + + align:start position:0% +the brain the Clos string can attct with + + + align:start position:0% +the brain the Clos string can attct with +the brain the Clos string can attct with + + align:start position:0% +the brain the Clos string can attct with + + + align:start position:0% +the brain the Clos string can attct with +open string in particular for example + + align:start position:0% +open string in particular for example + + + align:start position:0% +open string in particular for example +you can send the close string and + + align:start position:0% +you can send the close string and + + + align:start position:0% +you can send the close string and +absorbed by the brain and then Decay + + align:start position:0% +absorbed by the brain and then Decay + + + align:start position:0% +absorbed by the brain and then Decay +into open string is possible uh so this + + align:start position:0% +into open string is possible uh so this + + + align:start position:0% +into open string is possible uh so this +just corresponding to say yeah or or you + + align:start position:0% +just corresponding to say yeah or or you + + + align:start position:0% +just corresponding to say yeah or or you +can have two open string Collide then + + align:start position:0% +can have two open string Collide then + + + align:start position:0% +can have two open string Collide then +become a Clos string and then jump out + + align:start position:0% +become a Clos string and then jump out + + + align:start position:0% +become a Clos string and then jump out +of the brain yeah you can have all kind + + align:start position:0% +of the brain yeah you can have all kind + + + align:start position:0% +of the brain yeah you can have all kind +of this kind of interactions uh the key + + align:start position:0% +of this kind of interactions uh the key + + + align:start position:0% +of this kind of interactions uh the key +point is that in this + + align:start position:0% +point is that in this + + + align:start position:0% +point is that in this +description the only thing you need + + align:start position:0% +description the only thing you need + + + align:start position:0% +description the only thing you need +is the only thing you need is the derly + + align:start position:0% +is the only thing you need is the derly + + + align:start position:0% +is the only thing you need is the derly +boundary conditions specified on the um + + align:start position:0% +boundary conditions specified on the um + + + align:start position:0% +boundary conditions specified on the um +on your on some component of your um W + + align:start position:0% +on your on some component of your um W + + + align:start position:0% +on your on some component of your um W +sheet field for the screen + + align:start position:0% +sheet field for the screen + + + align:start position:0% +sheet field for the screen +okay so this is but now from here we + + align:start position:0% +okay so this is but now from here we + + + align:start position:0% +okay so this is but now from here we +have also found a different a second + + align:start position:0% +have also found a different a second + + + align:start position:0% +have also found a different a second +description is that we have SpaceTime + + align:start position:0% + + + + align:start position:0% + +matric + + align:start position:0% + + + + align:start position:0% + +one which is some curve space time then + + align:start position:0% +one which is some curve space time then + + + align:start position:0% +one which is some curve space time then +plus F5 + + align:start position:0% +plus F5 + + + align:start position:0% +plus F5 +FL on + + align:start position:0% + + + + align:start position:0% + +F5 okay so here there's no de brains + + align:start position:0% +F5 okay so here there's no de brains + + + align:start position:0% +F5 okay so here there's no de brains +anymore we just have some curve space + + align:start position:0% +anymore we just have some curve space + + + align:start position:0% +anymore we just have some curve space +time with some fluxes so here the the + + align:start position:0% +time with some fluxes so here the the + + + align:start position:0% +time with some fluxes so here the the +only thing needs is a close + + align:start position:0% + + + + align:start position:0% + +Str so + + align:start position:0% +Str so + + + align:start position:0% +Str so +only close + + align:start position:0% + + + + align:start position:0% + +strs but but those close string see a + + align:start position:0% +strs but but those close string see a + + + align:start position:0% +strs but but those close string see a +curves + + align:start position:0% +curves + + + align:start position:0% +curves +geometry okay so now I can include all + + align:start position:0% +geometry okay so now I can include all + + + align:start position:0% +geometry okay so now I can include all +Dimensions let me just draw the just to + + align:start position:0% +Dimensions let me just draw the just to + + + align:start position:0% +Dimensions let me just draw the just to +contrast this two let me draw this + + align:start position:0% +contrast this two let me draw this + + + align:start position:0% +contrast this two let me draw this +picture again now let's draw a 10 + + align:start position:0% +picture again now let's draw a 10 + + + align:start position:0% +picture again now let's draw a 10 +dimensional picture so this is R + + align:start position:0% +dimensional picture so this is R + + + align:start position:0% +dimensional picture so this is R +minkovski + + align:start position:0% +minkovski + + + align:start position:0% +minkovski +10 yeah so this is movy + + align:start position:0% +10 yeah so this is movy + + + align:start position:0% +10 yeah so this is movy +10 so when you know go to smaller radius + + align:start position:0% +10 so when you know go to smaller radius + + + align:start position:0% +10 so when you know go to smaller radius +R and then you develop infinite throat + + align:start position:0% +R and then you develop infinite throat + + + align:start position:0% +R and then you develop infinite throat +so this become Aus five + + align:start position:0% + + + + align:start position:0% + +times5 + + align:start position:0% +times5 + + + align:start position:0% +times5 +okay down the + + align:start position:0% +okay down the + + + align:start position:0% +okay down the +thir and here only Co string + + align:start position:0% +thir and here only Co string + + + align:start position:0% +thir and here only Co string +can can + + align:start position:0% +can can + + + align:start position:0% +can can +propagate there's no de brain but the co + + align:start position:0% +propagate there's no de brain but the co + + + align:start position:0% +propagate there's no de brain but the co +string can can add infinity can in ad is + + align:start position:0% +string can can add infinity can in ad is + + + align:start position:0% +string can can add infinity can in ad is +five so you can have Co strs okay + + align:start position:0% + + + + align:start position:0% + +so is this clear why we have close + + align:start position:0% +so is this clear why we have close + + + align:start position:0% +so is this clear why we have close +strings because in low energy cases it's + + align:start position:0% +strings because in low energy cases it's + + + align:start position:0% +strings because in low energy cases it's +no strings we only have a effective + + align:start position:0% +no strings we only have a effective + + + align:start position:0% +no strings we only have a effective +field but you can have yeah uh but this + + align:start position:0% +field but you can have yeah uh but this + + + align:start position:0% +field but you can have yeah uh but this +is a + + align:start position:0% +is a + + + align:start position:0% +is a +geometry this provide the geometry in + + align:start position:0% +geometry this provide the geometry in + + + align:start position:0% +geometry this provide the geometry in +principle close the excitations will be + + align:start position:0% +principle close the excitations will be + + + align:start position:0% +principle close the excitations will be +close Str so if you now you can do Str + + align:start position:0% +close Str so if you now you can do Str + + + align:start position:0% +close Str so if you now you can do Str +in this geometry oh oh I see yeah so now + + align:start position:0% +in this geometry oh oh I see yeah so now + + + align:start position:0% +in this geometry oh oh I see yeah so now +essentially treated as a targets new + + align:start position:0% +essentially treated as a targets new + + + align:start position:0% +essentially treated as a targets new +Target space and exactly oh and the do + + align:start position:0% +Target space and exactly oh and the do + + + align:start position:0% +Target space and exactly oh and the do +new stre exactly so so we start with a + + align:start position:0% +new stre exactly so so we start with a + + + align:start position:0% +new stre exactly so so we start with a +de brain and then we solve the geometry + + align:start position:0% +de brain and then we solve the geometry + + + align:start position:0% +de brain and then we solve the geometry +due to that de + + align:start position:0% +due to that de + + + align:start position:0% +due to that de +brain geometry due to that de brain and + + align:start position:0% +brain geometry due to that de brain and + + + align:start position:0% +brain geometry due to that de brain and +then now you can quantize the screen + + align:start position:0% +then now you can quantize the screen + + + align:start position:0% +then now you can quantize the screen +theory in that little geometry then that + + align:start position:0% +theory in that little geometry then that + + + align:start position:0% +theory in that little geometry then that +will describe how things intact with de + + align:start position:0% +will describe how things intact with de + + + align:start position:0% +will describe how things intact with de +brain okay yeah but in this picture + + align:start position:0% +brain okay yeah but in this picture + + + align:start position:0% +brain okay yeah but in this picture +there's no de anymore there only close + + align:start position:0% +there's no de anymore there only close + + + align:start position:0% +there's no de anymore there only close +JS Okay so so we just have uh + + align:start position:0% +JS Okay so so we just have uh + + + align:start position:0% +JS Okay so so we just have uh +yeah good + + align:start position:0% +yeah good + + + align:start position:0% +yeah good +yes H what was F5 F5 is the is the is + + align:start position:0% +yes H what was F5 F5 is the is the is + + + align:start position:0% +yes H what was F5 F5 is the is the is +the this F5 form of the tpe Tob stren + + align:start position:0% +the this F5 form of the tpe Tob stren + + + align:start position:0% +the this F5 form of the tpe Tob stren +which this this Rebrand carry the charge + + align:start position:0% +which this this Rebrand carry the charge + + + align:start position:0% +which this this Rebrand carry the charge +so this generalized charge I discussed + + align:start position:0% +so this generalized charge I discussed + + + align:start position:0% +so this generalized charge I discussed +last + + align:start position:0% + + + + align:start position:0% + +time other + + align:start position:0% + + + + align:start position:0% + +questions in last class that we know the + + align:start position:0% +questions in last class that we know the + + + align:start position:0% +questions in last class that we know the +F5 is from the effective + + align:start position:0% +F5 is from the effective + + + align:start position:0% +F5 is from the effective +Theory uh yeah and the effective theory + + align:start position:0% +Theory uh yeah and the effective theory + + + align:start position:0% +Theory uh yeah and the effective theory +is from the open string Spectrum no no + + align:start position:0% +is from the open string Spectrum no no + + + align:start position:0% +is from the open string Spectrum no no +no no F5 is close to Spectrum oh it's + + align:start position:0% +no no F5 is close to Spectrum oh it's + + + align:start position:0% +no no F5 is close to Spectrum oh it's +close toing Spectrum so why can you we + + align:start position:0% +close toing Spectrum so why can you we + + + align:start position:0% +close toing Spectrum so why can you we +why why can we apply string series twice + + align:start position:0% +why why can we apply string series twice + + + align:start position:0% +why why can we apply string series twice +I mean the first time we get a flx and + + align:start position:0% +I mean the first time we get a flx and + + + align:start position:0% +I mean the first time we get a flx and +then we get a modified Target space then + + align:start position:0% +then we get a modified Target space then + + + align:start position:0% +then we get a modified Target space then +we apply again yeah yeah you can yeah uh + + align:start position:0% +we apply again yeah yeah you can yeah uh + + + align:start position:0% +we apply again yeah yeah you can yeah uh +um streen Ser you can work with any c + + align:start position:0% +um streen Ser you can work with any c + + + align:start position:0% +um streen Ser you can work with any c +space time you can you can think about + + align:start position:0% +space time you can you can think about + + + align:start position:0% +space time you can you can think about +propagating a string in a generic c + + align:start position:0% +propagating a string in a generic c + + + align:start position:0% +propagating a string in a generic c +space + + align:start position:0% +space + + + align:start position:0% +space +time + + align:start position:0% + + + + align:start position:0% + +okay okay because it's it seems like uh + + align:start position:0% +okay okay because it's it seems like uh + + + align:start position:0% +okay okay because it's it seems like uh +the second application of string theory + + align:start position:0% +the second application of string theory + + + align:start position:0% +the second application of string theory +is like a higher correction no seems + + align:start position:0% +is like a higher correction no seems + + + align:start position:0% +is like a higher correction no seems +like no this picture this picture I'm + + align:start position:0% +like no this picture this picture I'm + + + align:start position:0% +like no this picture this picture I'm +just look at forget about deep brain I + + align:start position:0% +just look at forget about deep brain I + + + align:start position:0% +just look at forget about deep brain I +just look at some charged object I can + + align:start position:0% +just look at some charged object I can + + + align:start position:0% +just look at some charged object I can +look at some charged object in string + + align:start position:0% +look at some charged object in string + + + align:start position:0% +look at some charged object in string +ser and that object have some charge + + align:start position:0% +ser and that object have some charge + + + align:start position:0% +ser and that object have some charge +have some Mass then I will call this + + align:start position:0% +have some Mass then I will call this + + + align:start position:0% +have some Mass then I will call this +matric I will call this matric and the + + align:start position:0% +matric I will call this matric and the + + + align:start position:0% +matric I will call this matric and the +string must be able to live in that uh + + align:start position:0% +string must be able to live in that uh + + + align:start position:0% +string must be able to live in that uh +uh uh must be able to live in that + + align:start position:0% +uh uh must be able to live in that + + + align:start position:0% +uh uh must be able to live in that +matric and if we if I want to work out + + align:start position:0% +matric and if we if I want to work out + + + align:start position:0% +matric and if we if I want to work out +the property of the string then matri I + + align:start position:0% +the property of the string then matri I + + + align:start position:0% +the property of the string then matri I +Quant the string in this uh in this + + align:start position:0% +Quant the string in this uh in this + + + align:start position:0% +Quant the string in this uh in this +geometry qu stren so this point of view + + align:start position:0% +geometry qu stren so this point of view + + + align:start position:0% +geometry qu stren so this point of view +just purely to view the this brain as + + align:start position:0% +just purely to view the this brain as + + + align:start position:0% +just purely to view the this brain as +some charged object in the in the scen + + align:start position:0% +some charged object in the in the scen + + + align:start position:0% +some charged object in the in the scen +theory you you you just solve this + + align:start position:0% +theory you you you just solve this + + + align:start position:0% +theory you you you just solve this +your okay any other questions so this is + + align:start position:0% +your okay any other questions so this is + + + align:start position:0% +your okay any other questions so this is +a very important point this very + + align:start position:0% +a very important point this very + + + align:start position:0% +a very important point this very +important point so now the + + align:start position:0% +important point so now the + + + align:start position:0% +important point so now the +key the now the + + align:start position:0% +key the now the + + + align:start position:0% +key the now the +key is by consistency a must equal to + + align:start position:0% +key is by consistency a must equal to + + + align:start position:0% +key is by consistency a must equal to +B so these two distribution must be + + align:start position:0% +B so these two distribution must be + + + align:start position:0% +B so these two distribution must be +equivalent okay so this can be + + align:start position:0% +equivalent okay so this can be + + + align:start position:0% +equivalent okay so this can be +generalization as the simple exercise we + + align:start position:0% +generalization as the simple exercise we + + + align:start position:0% +generalization as the simple exercise we +described + + align:start position:0% +described + + + align:start position:0% +described +earlier that if you want to describe the + + align:start position:0% +earlier that if you want to describe the + + + align:start position:0% +earlier that if you want to describe the +the interaction between the two de + + align:start position:0% + + + + align:start position:0% + +brains you can use in two equivalent way + + align:start position:0% +brains you can use in two equivalent way + + + align:start position:0% +brains you can use in two equivalent way +why is to consider Some Loops of open + + align:start position:0% +why is to consider Some Loops of open + + + align:start position:0% +why is to consider Some Loops of open +strings which only need to consider the + + align:start position:0% +strings which only need to consider the + + + align:start position:0% +strings which only need to consider the +flat space just consider Loops of open + + align:start position:0% +flat space just consider Loops of open + + + align:start position:0% +flat space just consider Loops of open +strings or you can the gravit + + align:start position:0% +strings or you can the gravit + + + align:start position:0% +strings or you can the gravit +exchange between the two de BRS and + + align:start position:0% +exchange between the two de BRS and + + + align:start position:0% +exchange between the two de BRS and +gravit exchange between the two de BR is + + align:start position:0% +gravit exchange between the two de BR is + + + align:start position:0% +gravit exchange between the two de BR is +to view that the other de BR have + + align:start position:0% +to view that the other de BR have + + + align:start position:0% +to view that the other de BR have +already curved your space time and the + + align:start position:0% +already curved your space time and the + + + align:start position:0% +already curved your space time and the +the other de living in that curve space + + align:start position:0% +the other de living in that curve space + + + align:start position:0% +the other de living in that curve space +time so so so these are precise the + + align:start position:0% +time so so so these are precise the + + + align:start position:0% +time so so so these are precise the +generalization of that equivalent + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +now we have two object two description + + align:start position:0% +now we have two object two description + + + align:start position:0% +now we have two object two description +of De Brands which are completely + + align:start position:0% +of De Brands which are completely + + + align:start position:0% +of De Brands which are completely +different this one involving flash space + + align:start position:0% +different this one involving flash space + + + align:start position:0% +different this one involving flash space +and open and Clos string and this one + + align:start position:0% +and open and Clos string and this one + + + align:start position:0% +and open and Clos string and this one +only involing Clos but in some curve + + align:start position:0% +only involing Clos but in some curve + + + align:start position:0% +only involing Clos but in some curve +space time + + align:start position:0% +space time + + + align:start position:0% +space time +okay and in principle both + + align:start position:0% + + + + align:start position:0% + +descriptions can in + + align:start position:0% + + + + align:start position:0% + +principle the + + align:start position:0% + + + + align:start position:0% + +valid for all value of alpha + + align:start position:0% +valid for all value of alpha + + + align:start position:0% +valid for all value of alpha +Prime and G + + align:start position:0% +Prime and G + + + align:start position:0% +Prime and G +stren okay + + align:start position:0% + + + + align:start position:0% + +so the two parameters in the stren + + align:start position:0% +so the two parameters in the stren + + + align:start position:0% +so the two parameters in the stren +theory Alpha Prime and and but all Alpha + + align:start position:0% +theory Alpha Prime and and but all Alpha + + + align:start position:0% +theory Alpha Prime and and but all Alpha +Prime just consider for all energies uh + + align:start position:0% +Prime just consider for all energies uh + + + align:start position:0% +Prime just consider for all energies uh +uh uh + + align:start position:0% +uh uh + + + align:start position:0% +uh uh +yeah + + align:start position:0% + + + + align:start position:0% + +okay why it seems like they're con + + align:start position:0% +okay why it seems like they're con + + + align:start position:0% +okay why it seems like they're con +strain yeah yeah uh so so first in this + + align:start position:0% +strain yeah yeah uh so so first in this + + + align:start position:0% +strain yeah yeah uh so so first in this +picture there's no + + align:start position:0% +picture there's no + + + align:start position:0% +picture there's no +restriction on what is the alpha prime + + align:start position:0% +restriction on what is the alpha prime + + + align:start position:0% +restriction on what is the alpha prime +or G string and and you just impose D + + align:start position:0% +or G string and and you just impose D + + + align:start position:0% +or G string and and you just impose D +boundary condition and when you have a g + + align:start position:0% +boundary condition and when you have a g + + + align:start position:0% +boundary condition and when you have a g +string you just need to include the + + align:start position:0% +string you just need to include the + + + align:start position:0% +string you just need to include the +higher Loop diagrams + + align:start position:0% +higher Loop diagrams + + + align:start position:0% +higher Loop diagrams +Etc so so when we work out this + + align:start position:0% +Etc so so when we work out this + + + align:start position:0% +Etc so so when we work out this +geometry + + align:start position:0% +geometry + + + align:start position:0% +geometry +so so this statement is more try to + + align:start position:0% +so so this statement is more try to + + + align:start position:0% +so so this statement is more try to +apply to B in B when we apply when we + + align:start position:0% +apply to B in B when we apply when we + + + align:start position:0% +apply to B in B when we apply when we +work out this geometry and also uh uh + + align:start position:0% +work out this geometry and also uh uh + + + align:start position:0% +work out this geometry and also uh uh +this uh uh that a and S5 we were working + + align:start position:0% +this uh uh that a and S5 we were working + + + align:start position:0% +this uh uh that a and S5 we were working +using the approximation that the the + + align:start position:0% +using the approximation that the the + + + align:start position:0% +using the approximation that the the +alpha Prime should be small and the g + + align:start position:0% +alpha Prime should be small and the g + + + align:start position:0% +alpha Prime should be small and the g +string should be small + + align:start position:0% +string should be small + + + align:start position:0% +string should be small +yes but once you have worked out that + + align:start position:0% +yes but once you have worked out that + + + align:start position:0% +yes but once you have worked out that +solution in this regime in principle if + + align:start position:0% +solution in this regime in principle if + + + align:start position:0% +solution in this regime in principle if +you're technically powerful enough you + + align:start position:0% +you're technically powerful enough you + + + align:start position:0% +you're technically powerful enough you +should be able to extend this to to to + + align:start position:0% +should be able to extend this to to to + + + align:start position:0% +should be able to extend this to to to +General values of g string and Alpha + + align:start position:0% +General values of g string and Alpha + + + align:start position:0% +General values of g string and Alpha +prime it may not be precisely this + + align:start position:0% +prime it may not be precisely this + + + align:start position:0% +prime it may not be precisely this +matric but with some kind of deformation + + align:start position:0% +matric but with some kind of deformation + + + align:start position:0% +matric but with some kind of deformation +of that from alpha Prime Corrections and + + align:start position:0% +of that from alpha Prime Corrections and + + + align:start position:0% +of that from alpha Prime Corrections and +G string corrections but you should be + + align:start position:0% +G string corrections but you should be + + + align:start position:0% +G string corrections but you should be +able to do + + align:start position:0% +able to do + + + align:start position:0% +able to do +that yeah yeah I'm just say so that's + + align:start position:0% +that yeah yeah I'm just say so that's + + + align:start position:0% +that yeah yeah I'm just say so that's +why I say in + + align:start position:0% +why I say in + + + align:start position:0% +why I say in +principle okay + + align:start position:0% +principle okay + + + align:start position:0% +principle okay +so so we must have this two description + + align:start position:0% +so so we must have this two description + + + align:start position:0% +so so we must have this two description +and this two PR value for all range of + + align:start position:0% +and this two PR value for all range of + + + align:start position:0% +and this two PR value for all range of +the parameters you can you can be + + align:start position:0% +the parameters you can you can be + + + align:start position:0% +the parameters you can you can be +interested in + + align:start position:0% +interested in + + + align:start position:0% +interested in +okay and so this is a a very surprising + + align:start position:0% +okay and so this is a a very surprising + + + align:start position:0% +okay and so this is a a very surprising +statement this a equal to B but there's + + align:start position:0% +statement this a equal to B but there's + + + align:start position:0% +statement this a equal to B but there's +not much to to do about it because this + + align:start position:0% +not much to to do about it because this + + + align:start position:0% +not much to to do about it because this +is a complicated + + align:start position:0% +is a complicated + + + align:start position:0% +is a complicated +thing and this is also complicated thing + + align:start position:0% +thing and this is also complicated thing + + + align:start position:0% +thing and this is also complicated thing +this is even more complicated doing + + align:start position:0% +this is even more complicated doing + + + align:start position:0% +this is even more complicated doing +stren some curve space time in + + align:start position:0% +stren some curve space time in + + + align:start position:0% +stren some curve space time in +particular say if you consider string is + + align:start position:0% +particular say if you consider string is + + + align:start position:0% +particular say if you consider string is +very small Etc then maybe you can do + + align:start position:0% +very small Etc then maybe you can do + + + align:start position:0% +very small Etc then maybe you can do +something but then it's not that + + align:start position:0% +something but then it's not that + + + align:start position:0% +something but then it's not that +interesting because on both side you do + + align:start position:0% +interesting because on both side you do + + + align:start position:0% +interesting because on both side you do +some peration Theory Etc anyway + + align:start position:0% + + + + align:start position:0% + +so but the remarkable thing which M + + align:start position:0% +so but the remarkable thing which M + + + align:start position:0% +so but the remarkable thing which M +realized in + + align:start position:0% + + + + align:start position:0% + +1997 in + + align:start position:0% +1997 in + + + align:start position:0% +1997 in +1997 is said you can actually take a + + align:start position:0% +1997 is said you can actually take a + + + align:start position:0% +1997 is said you can actually take a +limit of this statement + + align:start position:0% +limit of this statement + + + align:start position:0% +limit of this statement +and when you take a limit of this + + align:start position:0% +and when you take a limit of this + + + align:start position:0% +and when you take a limit of this +statement then the statement become very + + align:start position:0% +statement then the statement become very + + + align:start position:0% +statement then the statement become very +interesting then you can actually do a + + align:start position:0% +interesting then you can actually do a + + + align:start position:0% +interesting then you can actually do a +lot okay and uh and uh and the limit is + + align:start position:0% +lot okay and uh and uh and the limit is + + + align:start position:0% +lot okay and uh and uh and the limit is +the Lage + + align:start position:0% +the Lage + + + align:start position:0% +the Lage +limit so if you consider the Lage + + align:start position:0% +limit so if you consider the Lage + + + align:start position:0% +limit so if you consider the Lage +limit then then you derive what is now + + align:start position:0% +limit then then you derive what is now + + + align:start position:0% +limit then then you derive what is now +called ads C of + + align:start position:0% +called ads C of + + + align:start position:0% +called ads C of +Correspondence we will now explain how + + align:start position:0% +Correspondence we will now explain how + + + align:start position:0% +Correspondence we will now explain how +to do + + align:start position:0% +to do + + + align:start position:0% +to do +that yes it seems like this + + align:start position:0% +that yes it seems like this + + + align:start position:0% +that yes it seems like this +correspondence between A and B only + + align:start position:0% +correspondence between A and B only + + + align:start position:0% +correspondence between A and B only +exists in the low energy limit because + + align:start position:0% +exists in the low energy limit because + + + align:start position:0% +exists in the low energy limit because +here the the the Clos strings traveling + + align:start position:0% +here the the the Clos strings traveling + + + align:start position:0% +here the the the Clos strings traveling +in the b space time that space time is + + align:start position:0% +in the b space time that space time is + + + align:start position:0% +in the b space time that space time is +only the low energy Corrections from the + + align:start position:0% +only the low energy Corrections from the + + + align:start position:0% +only the low energy Corrections from the +deep brain not the higher + + align:start position:0% +deep brain not the higher + + + align:start position:0% +deep brain not the higher +expectation um CU we only solved the low + + align:start position:0% +expectation um CU we only solved the low + + + align:start position:0% +expectation um CU we only solved the low +energy effective + + align:start position:0% +energy effective + + + align:start position:0% +energy effective +Theory no + + align:start position:0% +Theory no + + + align:start position:0% +Theory no +that's this is a good question but + + align:start position:0% +that's this is a good question but + + + align:start position:0% +that's this is a good question but +that's what I was trying to uh say + + align:start position:0% +that's what I was trying to uh say + + + align:start position:0% +that's what I was trying to uh say +earlier so we find this + + align:start position:0% +earlier so we find this + + + align:start position:0% +earlier so we find this +matric by working in this regime + + align:start position:0% +matric by working in this regime + + + align:start position:0% +matric by working in this regime +but now if I want to go away from this + + align:start position:0% +but now if I want to go away from this + + + align:start position:0% +but now if I want to go away from this +regime if I want to go away from this + + align:start position:0% +regime if I want to go away from this + + + align:start position:0% +regime if I want to go away from this +regime then + + align:start position:0% +regime then + + + align:start position:0% +regime then +um if I want to go away from this regime + + align:start position:0% +um if I want to go away from this regime + + + align:start position:0% +um if I want to go away from this regime +then I have to take into account other + + align:start position:0% +then I have to take into account other + + + align:start position:0% +then I have to take into account other +Prime crash EXC and this is a + + align:start position:0% +Prime crash EXC and this is a + + + align:start position:0% +Prime crash EXC and this is a +complicated process but in principle I + + align:start position:0% +complicated process but in principle I + + + align:start position:0% +complicated process but in principle I +can do that yeah in principle I can do + + align:start position:0% +can do that yeah in principle I can do + + + align:start position:0% +can do that yeah in principle I can do +that so so so so that geometry may get + + align:start position:0% +that so so so so that geometry may get + + + align:start position:0% +that so so so so that geometry may get +modified sketch but in PR something in + + align:start position:0% +modified sketch but in PR something in + + + align:start position:0% +modified sketch but in PR something in +principle I can + + align:start position:0% +principle I can + + + align:start position:0% +principle I can +do and + + align:start position:0% +do and + + + align:start position:0% +do and +now + + align:start position:0% +now + + + align:start position:0% +now +so + + align:start position:0% +so + + + align:start position:0% +so +um so now it turns out if you consider + + align:start position:0% +um so now it turns out if you consider + + + align:start position:0% +um so now it turns out if you consider +low limit of this a equal to B then you + + align:start position:0% +low limit of this a equal to B then you + + + align:start position:0% +low limit of this a equal to B then you +can actually derive a very powerful + + align:start position:0% +can actually derive a very powerful + + + align:start position:0% +can actually derive a very powerful +statement okay is this actually is a ler + + align:start position:0% +statement okay is this actually is a ler + + + align:start position:0% +statement okay is this actually is a ler +limit no this is no this itself is not + + align:start position:0% +limit no this is no this itself is not + + + align:start position:0% +limit no this is no this itself is not +lower limit this is a classical gravity + + align:start position:0% +lower limit this is a classical gravity + + + align:start position:0% +lower limit this is a classical gravity +limit what's the difference H what's the + + align:start position:0% +limit what's the difference H what's the + + + align:start position:0% +limit what's the difference H what's the +difference I will explain that no this + + align:start position:0% +difference I will explain that no this + + + align:start position:0% +difference I will explain that no this +is the classical gravity limit okay and + + align:start position:0% +is the classical gravity limit okay and + + + align:start position:0% +is the classical gravity limit okay and +and at least the Lage limit does not + + align:start position:0% +and at least the Lage limit does not + + + align:start position:0% +and at least the Lage limit does not +involve this + + align:start position:0% +involve this + + + align:start position:0% +involve this +does not invol yeah I will explain what + + align:start position:0% +does not invol yeah I will explain what + + + align:start position:0% +does not invol yeah I will explain what +this No Limit yeah any other + + align:start position:0% + + + + align:start position:0% + +questions good okay so now let's look at + + align:start position:0% + + + + align:start position:0% + +limit in + + align:start position:0% +limit in + + + align:start position:0% +limit in +particular here I don't do any + + align:start position:0% +particular here I don't do any + + + align:start position:0% +particular here I don't do any +restriction on the G string so G string + + align:start position:0% +restriction on the G string so G string + + + align:start position:0% +restriction on the G string so G string +can in principle be strong here I don't + + align:start position:0% +can in principle be strong here I don't + + + align:start position:0% +can in principle be strong here I don't +impose any constraint on the string + + align:start position:0% +impose any constraint on the string + + + align:start position:0% +impose any constraint on the string +coupling now I only consider the energy + + align:start position:0% +coupling now I only consider the energy + + + align:start position:0% +coupling now I only consider the energy +okay so the low energy limit + + align:start position:0% +okay so the low energy limit + + + align:start position:0% +okay so the low energy limit +corresponding to I fix the energy e some + + align:start position:0% +corresponding to I fix the energy e some + + + align:start position:0% +corresponding to I fix the energy e some +energy some + + align:start position:0% +energy some + + + align:start position:0% +energy some +process I'm interested in some typical + + align:start position:0% +process I'm interested in some typical + + + align:start position:0% +process I'm interested in some typical +energy I'm interested + + align:start position:0% +energy I'm interested + + + align:start position:0% +energy I'm interested +in then then I want to take the the + + align:start position:0% +in then then I want to take the the + + + align:start position:0% +in then then I want to take the the +alpha Prime go to zero + + align:start position:0% +alpha Prime go to zero + + + align:start position:0% +alpha Prime go to zero +limit okay or or you fix + + align:start position:0% +limit okay or or you fix + + + align:start position:0% +limit okay or or you fix +the equivalent you can fix Alpha Prime + + align:start position:0% +the equivalent you can fix Alpha Prime + + + align:start position:0% +the equivalent you can fix Alpha Prime +then you take equal to zero okay because + + align:start position:0% +then you take equal to zero okay because + + + align:start position:0% +then you take equal to zero okay because +only the dimension is product of the + + align:start position:0% +only the dimension is product of the + + + align:start position:0% +only the dimension is product of the +matters and I can describe either way + + align:start position:0% +matters and I can describe either way + + + align:start position:0% +matters and I can describe either way +okay so so physically uh what is more + + align:start position:0% +okay so so physically uh what is more + + + align:start position:0% +okay so so physically uh what is more +convenient normally mathematically + + align:start position:0% +convenient normally mathematically + + + align:start position:0% +convenient normally mathematically +normally what is more convenient is that + + align:start position:0% +normally what is more convenient is that + + + align:start position:0% +normally what is more convenient is that +we think we fix e and then take Al Prim + + align:start position:0% +we think we fix e and then take Al Prim + + + align:start position:0% +we think we fix e and then take Al Prim +go zero but you can think either way + + align:start position:0% +go zero but you can think either way + + + align:start position:0% +go zero but you can think either way +okay so the low energ limit essentially + + align:start position:0% +okay so the low energ limit essentially + + + align:start position:0% +okay so the low energ limit essentially +just the the limit Alpha Prime Time e s + + align:start position:0% +just the the limit Alpha Prime Time e s + + + align:start position:0% +just the the limit Alpha Prime Time e s +goes zero uh uh uh uh that's the + + align:start position:0% +goes zero uh uh uh uh that's the + + + align:start position:0% +goes zero uh uh uh uh that's the +dimensional statement okay so this is + + align:start position:0% +dimensional statement okay so this is + + + align:start position:0% +dimensional statement okay so this is +the low limit I only consider those + + align:start position:0% +the low limit I only consider those + + + align:start position:0% +the low limit I only consider those +physical process with E that would + + align:start position:0% +physical process with E that would + + + align:start position:0% +physical process with E that would +satisfy this + + align:start position:0% +satisfy this + + + align:start position:0% +satisfy this +region + + align:start position:0% +region + + + align:start position:0% +region +okay + + align:start position:0% +okay + + + align:start position:0% +okay +good and uh I'm do doing no restriction + + align:start position:0% +good and uh I'm do doing no restriction + + + align:start position:0% +good and uh I'm do doing no restriction +on the + + align:start position:0% +on the + + + align:start position:0% +on the +GS so now let's consider a what is the L + + align:start position:0% +GS so now let's consider a what is the L + + + align:start position:0% +GS so now let's consider a what is the L +limit for + + align:start position:0% + + + + align:start position:0% + +a for a we + + align:start position:0% +a for a we + + + align:start position:0% +a for a we +know so a we have two sectors we have + + align:start position:0% +know so a we have two sectors we have + + + align:start position:0% +know so a we have two sectors we have +open string sector which is leave on the + + align:start position:0% +open string sector which is leave on the + + + align:start position:0% +open string sector which is leave on the +deep brain then we also have closed + + align:start position:0% +deep brain then we also have closed + + + align:start position:0% +deep brain then we also have closed +string sector + + align:start position:0% +string sector + + + align:start position:0% +string sector +okay uh which leave outside the brain + + align:start position:0% +okay uh which leave outside the brain + + + align:start position:0% +okay uh which leave outside the brain +for the open string + + align:start position:0% + + + + align:start position:0% + +sector we just recover so we discussed + + align:start position:0% +sector we just recover so we discussed + + + align:start position:0% +sector we just recover so we discussed +before when in on the Deep bre when you + + align:start position:0% +before when in on the Deep bre when you + + + align:start position:0% +before when in on the Deep bre when you +go to low + + align:start position:0% +go to low + + + align:start position:0% +go to low +energy what do you + + align:start position:0% + + + + align:start position:0% + +get super yes you just recover y series + + align:start position:0% +get super yes you just recover y series + + + align:start position:0% +get super yes you just recover y series +just recover super M ser and in this + + align:start position:0% +just recover super M ser and in this + + + align:start position:0% +just recover super M ser and in this +case let me give you a special name for + + align:start position:0% +case let me give you a special name for + + + align:start position:0% +case let me give you a special name for +the this three brain it turn out you you + + align:start position:0% +the this three brain it turn out you you + + + align:start position:0% +the this three brain it turn out you you +get the inity for super Yos just a + + align:start position:0% +get the inity for super Yos just a + + + align:start position:0% +get the inity for super Yos just a +specific Super Y Ser in four dimension + + align:start position:0% +specific Super Y Ser in four dimension + + + align:start position:0% +specific Super Y Ser in four dimension +and we skage + + align:start position:0% +and we skage + + + align:start position:0% +and we skage +group + + align:start position:0% +group + + + align:start position:0% +group +un okay because we have consider deep + + align:start position:0% +un okay because we have consider deep + + + align:start position:0% +un okay because we have consider deep +brains and deep + + align:start position:0% +brains and deep + + + align:start position:0% +brains and deep +brains and uh and in particular as we + + align:start position:0% +brains and uh and in particular as we + + + align:start position:0% +brains and uh and in particular as we +said before the yam + + align:start position:0% +said before the yam + + + align:start position:0% +said before the yam +coupling is + + align:start position:0% +coupling is + + + align:start position:0% +coupling is +related to the G + + align:start position:0% +related to the G + + + align:start position:0% +related to the G +GS okay it's propon to the + + align:start position:0% +GS okay it's propon to the + + + align:start position:0% +GS okay it's propon to the +GS and uh so so this re brain give rise + + align:start position:0% +GS and uh so so this re brain give rise + + + align:start position:0% +GS and uh so so this re brain give rise +to a three plus one dimensional fi Ser + + align:start position:0% +to a three plus one dimensional fi Ser + + + align:start position:0% +to a three plus one dimensional fi Ser +in the three plus one dimensional fi + + align:start position:0% +in the three plus one dimensional fi + + + align:start position:0% +in the three plus one dimensional fi +series the Y's comping is dimensionless + + align:start position:0% +series the Y's comping is dimensionless + + + align:start position:0% +series the Y's comping is dimensionless +so there's no other dimensional + + align:start position:0% +so there's no other dimensional + + + align:start position:0% +so there's no other dimensional +parameter here so there's only so so + + align:start position:0% +parameter here so there's only so so + + + align:start position:0% +parameter here so there's only so so +there's only numerical fact be 4 Pi + + align:start position:0% +there's only numerical fact be 4 Pi + + + align:start position:0% +there's only numerical fact be 4 Pi +which you can work out by expit + + align:start position:0% +which you can work out by expit + + + align:start position:0% +which you can work out by expit +calculations so this is key because if + + align:start position:0% +calculations so this is key because if + + + align:start position:0% +calculations so this is key because if +there's a a scale here then the story is + + align:start position:0% +there's a a scale here then the story is + + + align:start position:0% +there's a a scale here then the story is +more complicated because the because you + + align:start position:0% +more complicated because the because you + + + align:start position:0% +more complicated because the because you +have to take Alpha goes zero Etc okay so + + align:start position:0% +have to take Alpha goes zero Etc okay so + + + align:start position:0% +have to take Alpha goes zero Etc okay so +the key is that this is a dimension is + + align:start position:0% +the key is that this is a dimension is + + + align:start position:0% +the key is that this is a dimension is +coupling they have see simple + + align:start position:0% +coupling they have see simple + + + align:start position:0% +coupling they have see simple +relation so in open string when you take + + align:start position:0% +relation so in open string when you take + + + align:start position:0% +relation so in open string when you take +the L limit you just get a y the as some + + align:start position:0% +the L limit you just get a y the as some + + + align:start position:0% +the L limit you just get a y the as some +F at coupling okay which is determined + + align:start position:0% +F at coupling okay which is determined + + + align:start position:0% +F at coupling okay which is determined +by the string coupling + + align:start position:0% +by the string coupling + + + align:start position:0% +by the string coupling +Conant but in this series there's also a + + align:start position:0% +Conant but in this series there's also a + + + align:start position:0% +Conant but in this series there's also a +close + + align:start position:0% + + + + align:start position:0% + +sector in a + + align:start position:0% + + + + align:start position:0% + +sector again when you take low limit you + + align:start position:0% +sector again when you take low limit you + + + align:start position:0% +sector again when you take low limit you +get the mless modes you get + + align:start position:0% + + + + align:start position:0% + +graviton + + align:start position:0% + + + + align:start position:0% + +Daton Etc but only mes modes + + align:start position:0% + + + + align:start position:0% + +okay but now there's a very important + + align:start position:0% +okay but now there's a very important + + + align:start position:0% +okay but now there's a very important +point + + align:start position:0% + + + + align:start position:0% + +the coupling between the closed and open + + align:start position:0% +the coupling between the closed and open + + + align:start position:0% +the coupling between the closed and open +string are mediated through + + align:start position:0% +string are mediated through + + + align:start position:0% +string are mediated through +gravitational effect okay so the + + align:start position:0% + + + + align:start position:0% + +comping between the mass so only Mass + + align:start position:0% +comping between the mass so only Mass + + + align:start position:0% +comping between the mass so only Mass +mod left so the cing between the + + align:start position:0% +mod left so the cing between the + + + align:start position:0% +mod left so the cing between the +Mist + + align:start position:0% +Mist + + + align:start position:0% +Mist +closed and open + + align:start position:0% + + + + align:start position:0% + +string + + align:start position:0% +string + + + align:start position:0% +string +all closeing + + align:start position:0% + + + + align:start position:0% + +themselves all closing + + align:start position:0% + + + + align:start position:0% + +themselves those + + align:start position:0% + + + + align:start position:0% + +interactions just it's always controlled + + align:start position:0% +interactions just it's always controlled + + + align:start position:0% +interactions just it's always controlled +by G Newton this weow because this is + + align:start position:0% +by G Newton this weow because this is + + + align:start position:0% +by G Newton this weow because this is +the low energy limit you have grav contr + + align:start position:0% +the low energy limit you have grav contr + + + align:start position:0% +the low energy limit you have grav contr +by G Newton + + align:start position:0% +by G Newton + + + align:start position:0% +by G Newton +it's gravitational by gravitational + + align:start position:0% +it's gravitational by gravitational + + + align:start position:0% +it's gravitational by gravitational +interactions but now the key the key is + + align:start position:0% +interactions but now the key the key is + + + align:start position:0% +interactions but now the key the key is +that J Newton in contrast to this yam + + align:start position:0% +that J Newton in contrast to this yam + + + align:start position:0% +that J Newton in contrast to this yam +cing which is dimension this G Newton is + + align:start position:0% +cing which is dimension this G Newton is + + + align:start position:0% +cing which is dimension this G Newton is +dimensional and G Newton is proportional + + align:start position:0% +dimensional and G Newton is proportional + + + align:start position:0% +dimensional and G Newton is proportional +to G s² Alpha Prime to the power + + align:start position:0% + + + + align:start position:0% + +4 so that means in the low energy + + align:start position:0% + + + + align:start position:0% + +limit then the dimension is + + align:start position:0% +limit then the dimension is + + + align:start position:0% +limit then the dimension is +cing then the dimension is parameter is + + align:start position:0% +cing then the dimension is parameter is + + + align:start position:0% +cing then the dimension is parameter is +g to the power say 8 because this have + + align:start position:0% +g to the power say 8 because this have + + + align:start position:0% +g to the power say 8 because this have +Dimension eight so this a dimension this + + align:start position:0% +Dimension eight so this a dimension this + + + align:start position:0% +Dimension eight so this a dimension this +will go + + align:start position:0% +will go + + + align:start position:0% +will go +zero + + align:start position:0% +zero + + + align:start position:0% +zero +okay so that actually tells you in the + + align:start position:0% +okay so that actually tells you in the + + + align:start position:0% +okay so that actually tells you in the +know + + align:start position:0% +know + + + align:start position:0% +know +limit the the the interaction between + + align:start position:0% +limit the the the interaction between + + + align:start position:0% +limit the the the interaction between +open and closing with decouple okay this + + align:start position:0% +open and closing with decouple okay this + + + align:start position:0% +open and closing with decouple okay this +is our familiar + + align:start position:0% +is our familiar + + + align:start position:0% +is our familiar +fact that electron when we talk about + + align:start position:0% +fact that electron when we talk about + + + align:start position:0% +fact that electron when we talk about +electron you don't have to talk about + + align:start position:0% +electron you don't have to talk about + + + align:start position:0% +electron you don't have to talk about +gravity because the energy Sol low the + + align:start position:0% +gravity because the energy Sol low the + + + align:start position:0% +gravity because the energy Sol low the +gravity is so weak okay and the gravity + + align:start position:0% +gravity is so weak okay and the gravity + + + align:start position:0% +gravity is so weak okay and the gravity +only become strong if the energy become + + align:start position:0% +only become strong if the energy become + + + align:start position:0% +only become strong if the energy become +big + + align:start position:0% +big + + + align:start position:0% +big +okay just because of this in 3 + one we + + align:start position:0% +okay just because of this in 3 + one we + + + align:start position:0% +okay just because of this in 3 + one we +just GN * e s but here we in 10 + + align:start position:0% +just GN * e s but here we in 10 + + + align:start position:0% +just GN * e s but here we in 10 +Dimensions e to the^ a doesn't + + align:start position:0% +Dimensions e to the^ a doesn't + + + align:start position:0% +Dimensions e to the^ a doesn't +matter so so now that + + align:start position:0% +matter so so now that + + + align:start position:0% +matter so so now that +means in the equal to zero + + align:start position:0% +means in the equal to zero + + + align:start position:0% +means in the equal to zero +limit what we find is we find the + + align:start position:0% +limit what we find is we find the + + + align:start position:0% +limit what we find is we find the +interacting in for super Y3 + + align:start position:0% +interacting in for super Y3 + + + align:start position:0% +interacting in for super Y3 +plus three + + align:start position:0% + + + + align:start position:0% + +gravitons plus other Methodist modes but + + align:start position:0% +gravitons plus other Methodist modes but + + + align:start position:0% +gravitons plus other Methodist modes but +they all become free because the the + + align:start position:0% +they all become free because the the + + + align:start position:0% +they all become free because the the +interaction essentially switch off any + + align:start position:0% +interaction essentially switch off any + + + align:start position:0% +interaction essentially switch off any +interaction this sector this reach off + + align:start position:0% +interaction this sector this reach off + + + align:start position:0% +interaction this sector this reach off +in particular there's no interaction + + align:start position:0% +in particular there's no interaction + + + align:start position:0% +in particular there's no interaction +between these two + + align:start position:0% +between these two + + + align:start position:0% +between these two +sector + + align:start position:0% +sector + + + align:start position:0% +sector +okay so so this what we get on the uh a + + align:start position:0% +okay so so this what we get on the uh a + + + align:start position:0% +okay so so this what we get on the uh a +picture + + align:start position:0% + + + + align:start position:0% + +actually + + align:start position:0% +actually + + + align:start position:0% +actually +e e I'm just saying this is the + + align:start position:0% +e e I'm just saying this is the + + + align:start position:0% +e e I'm just saying this is the +dimension is combination of + + align:start position:0% +dimension is combination of + + + align:start position:0% +dimension is combination of +them it's the actual C no the actual C + + align:start position:0% +them it's the actual C no the actual C + + + align:start position:0% +them it's the actual C no the actual C +can be2 can be square root of the contr + + align:start position:0% +can be2 can be square root of the contr + + + align:start position:0% +can be2 can be square root of the contr +by the Jon the key thing is contr by Jon + + align:start position:0% +by the Jon the key thing is contr by Jon + + + align:start position:0% +by the Jon the key thing is contr by Jon +and Jon is a + + align:start position:0% +and Jon is a + + + align:start position:0% +and Jon is a +dimension is a dimensional + + align:start position:0% +dimension is a dimensional + + + align:start position:0% +dimension is a dimensional +parameter that's just the key yes why + + align:start position:0% +parameter that's just the key yes why + + + align:start position:0% +parameter that's just the key yes why +can't they through G + + align:start position:0% +can't they through G + + + align:start position:0% +can't they through G +or no the g b interact with themselves + + align:start position:0% +or no the g b interact with themselves + + + align:start position:0% +or no the g b interact with themselves +the interaction of the guge Bon with + + align:start position:0% +the interaction of the guge Bon with + + + align:start position:0% +the interaction of the guge Bon with +graviton is gravitational have to go + + align:start position:0% +graviton is gravitational have to go + + + align:start position:0% +graviton is gravitational have to go +through + + align:start position:0% + + + + align:start position:0% + +gon the gaug bottom inag with themselves + + align:start position:0% +gon the gaug bottom inag with themselves + + + align:start position:0% +gon the gaug bottom inag with themselves +is captured by + + align:start position:0% +is captured by + + + align:start position:0% +is captured by +here so anything involving gravity + + align:start position:0% +here so anything involving gravity + + + align:start position:0% +here so anything involving gravity +involve dimensional cing then they will + + align:start position:0% +involve dimensional cing then they will + + + align:start position:0% +involve dimensional cing then they will +switch off in the low energy limit just + + align:start position:0% +switch off in the low energy limit just + + + align:start position:0% +switch off in the low energy limit just +like we don't have to worry about the uh + + align:start position:0% +like we don't have to worry about the uh + + + align:start position:0% +like we don't have to worry about the uh +uh uh the gravitational + + align:start position:0% +uh uh the gravitational + + + align:start position:0% +uh uh the gravitational +inaction of electron when we talk about + + align:start position:0% +inaction of electron when we talk about + + + align:start position:0% +inaction of electron when we talk about +hydrogen + + align:start position:0% +hydrogen + + + align:start position:0% +hydrogen +atom no but we know that from qft course + + align:start position:0% +atom no but we know that from qft course + + + align:start position:0% +atom no but we know that from qft course +but how do we see from here that no no + + align:start position:0% +but how do we see from here that no no + + + align:start position:0% +but how do we see from here that no no +no no you just from + + align:start position:0% +no no you just from + + + align:start position:0% +no no you just from +here no no no this is just the + + align:start position:0% +here no no no this is just the + + + align:start position:0% +here no no no this is just the +thing you can calculate the C you can + + align:start position:0% +thing you can calculate the C you can + + + align:start position:0% +thing you can calculate the C you can +calculate you can calculate precisely + + align:start position:0% +calculate you can calculate precisely + + + align:start position:0% +calculate you can calculate precisely +work out the uh the scattering amplitude + + align:start position:0% +work out the uh the scattering amplitude + + + align:start position:0% +work out the uh the scattering amplitude +between the photon and graviton take the + + align:start position:0% +between the photon and graviton take the + + + align:start position:0% +between the photon and graviton take the +L you find that scattering goes to zero + + align:start position:0% +L you find that scattering goes to zero + + + align:start position:0% +L you find that scattering goes to zero +uh you will you can do that calculation + + align:start position:0% +uh you will you can do that calculation + + + align:start position:0% +uh you will you can do that calculation +expc and take the limit but this + + align:start position:0% +expc and take the limit but this + + + align:start position:0% +expc and take the limit but this +argument tells you that you don't have + + align:start position:0% +argument tells you that you don't have + + + align:start position:0% +argument tells you that you don't have +to do the calculation you will always + + align:start position:0% + + + + align:start position:0% + +work okay so now let's look at picture + + align:start position:0% +work okay so now let's look at picture + + + align:start position:0% +work okay so now let's look at picture +B when we take the low limit and now + + align:start position:0% +B when we take the low limit and now + + + align:start position:0% +B when we take the low limit and now +let's go back to this + + align:start position:0% +let's go back to this + + + align:start position:0% +let's go back to this +matric now let's go back to this matric + + align:start position:0% +matric now let's go back to this matric + + + align:start position:0% +matric now let's go back to this matric +so actually it's + + align:start position:0% +so actually it's + + + align:start position:0% +so actually it's +handy so now let's look at picture B the + + align:start position:0% +handy so now let's look at picture B the + + + align:start position:0% +handy so now let's look at picture B the +L limit let's look at this + + align:start position:0% + + + + align:start position:0% + +magic so this is a curve space + + align:start position:0% +magic so this is a curve space + + + align:start position:0% +magic so this is a curve space +time so when we take low energ limit we + + align:start position:0% +time so when we take low energ limit we + + + align:start position:0% +time so when we take low energ limit we +have to be + + align:start position:0% +have to be + + + align:start position:0% +have to be +careful because one repeated one + + align:start position:0% +careful because one repeated one + + + align:start position:0% +careful because one repeated one +important thing you always keep in mind + + align:start position:0% +important thing you always keep in mind + + + align:start position:0% +important thing you always keep in mind +when you have a curple space time the + + align:start position:0% +when you have a curple space time the + + + align:start position:0% +when you have a curple space time the +time depend on where you sit you have to + + align:start position:0% +time depend on where you sit you have to + + + align:start position:0% +time depend on where you sit you have to +always specify a reference time because + + align:start position:0% +always specify a reference time because + + + align:start position:0% +always specify a reference time because +time is no longer the absolute thing + + align:start position:0% +time is no longer the absolute thing + + + align:start position:0% +time is no longer the absolute thing +okay because the the local time EXA you + + align:start position:0% +okay because the the local time EXA you + + + align:start position:0% +okay because the the local time EXA you +have to specify your time frame + + align:start position:0% +have to specify your time frame + + + align:start position:0% +have to specify your time frame +okay and so so we have to ask what is + + align:start position:0% +okay and so so we have to ask what is + + + align:start position:0% +okay and so so we have to ask what is +this + + align:start position:0% + + + + align:start position:0% + +e in picture a translate into this + + align:start position:0% +e in picture a translate into this + + + align:start position:0% +e in picture a translate into this +picture in picture a everything is in + + align:start position:0% +picture in picture a everything is in + + + align:start position:0% +picture in picture a everything is in +movi space + + align:start position:0% +movi space + + + align:start position:0% +movi space +time and that e is essentially + + align:start position:0% +time and that e is essentially + + + align:start position:0% +time and that e is essentially +e of the for the for the m case time at + + align:start position:0% +e of the for the for the m case time at + + + align:start position:0% +e of the for the for the m case time at +Infinity in the picture B okay so in + + align:start position:0% +Infinity in the picture B okay so in + + + align:start position:0% +Infinity in the picture B okay so in +other words the + + align:start position:0% +other words the + + + align:start position:0% +other words the +e in other was so here yeah let me just + + align:start position:0% +e in other was so here yeah let me just + + + align:start position:0% +e in other was so here yeah let me just +say the curve space + + align:start position:0% + + + + align:start position:0% + +time must be + + align:start position:0% + + + + align:start position:0% + +careful to + + align:start position:0% + + + + align:start position:0% + +specify what energy we interested in + + align:start position:0% +specify what energy we interested in + + + align:start position:0% +specify what energy we interested in +what energy we talking about + + align:start position:0% + + + + align:start position:0% + +okay so the energy depend on the your + + align:start position:0% +okay so the energy depend on the your + + + align:start position:0% +okay so the energy depend on the your +your choice of time or depend on your + + align:start position:0% +your choice of time or depend on your + + + align:start position:0% +your choice of time or depend on your +Observer + + align:start position:0% + + + + align:start position:0% + +okay so so but we have to but in order + + align:start position:0% +okay so so but we have to but in order + + + align:start position:0% +okay so so but we have to but in order +to compare a with B we have to translate + + align:start position:0% +to compare a with B we have to translate + + + align:start position:0% +to compare a with B we have to translate +what is e in + + align:start position:0% + + + + align:start position:0% + +a + + align:start position:0% + + + + align:start position:0% + +this is translate into B is + + align:start position:0% +this is translate into B is + + + align:start position:0% +this is translate into B is +defined respect + + align:start position:0% +defined respect + + + align:start position:0% +defined respect +to the + + align:start position:0% + + + + align:start position:0% + +T this T there okay uh in other words is + + align:start position:0% +T this T there okay uh in other words is + + + align:start position:0% +T this T there okay uh in other words is +the + + align:start position:0% +the + + + align:start position:0% +the +time at I equal to + + align:start position:0% +time at I equal to + + + align:start position:0% +time at I equal to +Infinity + + align:start position:0% +Infinity + + + align:start position:0% +Infinity +okay so that energy scale is defined + + align:start position:0% +okay so that energy scale is defined + + + align:start position:0% +okay so that energy scale is defined +with that to to that specific uh a + + align:start position:0% + + + + align:start position:0% + +time but now when we talk about the + + align:start position:0% +time but now when we talk about the + + + align:start position:0% +time but now when we talk about the +physics happening in this space time for + + align:start position:0% +physics happening in this space time for + + + align:start position:0% +physics happening in this space time for +example we talking about string series + + align:start position:0% +example we talking about string series + + + align:start position:0% +example we talking about string series +string excitations or the mass of the + + align:start position:0% +string excitations or the mass of the + + + align:start position:0% +string excitations or the mass of the +string or excit you have to refer to the + + align:start position:0% +string or excit you have to refer to the + + + align:start position:0% +string or excit you have to refer to the +local proper time at whatever Place uh + + align:start position:0% +local proper time at whatever Place uh + + + align:start position:0% +local proper time at whatever Place uh +other uh at whatever Place uh you are + + align:start position:0% +other uh at whatever Place uh you are + + + align:start position:0% +other uh at whatever Place uh you are +talking about uh uh your physical + + align:start position:0% +talking about uh uh your physical + + + align:start position:0% +talking about uh uh your physical +process + + align:start position:0% +process + + + align:start position:0% +process +okay so that + + align:start position:0% + + + + align:start position:0% + +means oh actually today we are + + align:start position:0% +means oh actually today we are + + + align:start position:0% +means oh actually today we are +going um to + + align:start position:0% +going um to + + + align:start position:0% +going um to +6:30 oh yeah right + + align:start position:0% + + + + align:start position:0% + +um so suppose you are at some location r + + align:start position:0% +um so suppose you are at some location r + + + align:start position:0% +um so suppose you are at some location r +then the local prop + + align:start position:0% + + + + align:start position:0% + +time which have + + align:start position:0% + + + + align:start position:0% + +qu local prop time the to then it's + + align:start position:0% +qu local prop time the to then it's + + + align:start position:0% +qu local prop time the to then it's +related to the time at Infinity by this + + align:start position:0% +related to the time at Infinity by this + + + align:start position:0% +related to the time at Infinity by this +Factor okay by this Factor just this the + + align:start position:0% +Factor okay by this Factor just this the + + + align:start position:0% +Factor okay by this Factor just this the +local Observer equ call this your D + + align:start position:0% +local Observer equ call this your D + + + align:start position:0% +local Observer equ call this your D +Square so uh so so they relate to this + + align:start position:0% +Square so uh so so they relate to this + + + align:start position:0% +Square so uh so so they relate to this +by by this + + align:start position:0% +by by this + + + align:start position:0% +by by this +Factor so now you can reasing convert + + align:start position:0% +Factor so now you can reasing convert + + + align:start position:0% +Factor so now you can reasing convert +then the local proper energy is related + + align:start position:0% +then the local proper energy is related + + + align:start position:0% +then the local proper energy is related +to the energy we are talking about here + + align:start position:0% +to the energy we are talking about here + + + align:start position:0% +to the energy we are talking about here +by h to^ + + align:start position:0% +by h to^ + + + align:start position:0% +by h to^ +one4 e + + align:start position:0% + + + + align:start position:0% + +okay okay so now tonight it's very + + align:start position:0% +okay okay so now tonight it's very + + + align:start position:0% +okay okay so now tonight it's very +important when we take the L limit we + + align:start position:0% +important when we take the L limit we + + + align:start position:0% +important when we take the L limit we +take this e + + align:start position:0% +take this e + + + align:start position:0% +take this e +small but due to the gravitational red + + align:start position:0% +small but due to the gravitational red + + + align:start position:0% +small but due to the gravitational red +shift effect this e does not have to be + + align:start position:0% +shift effect this e does not have to be + + + align:start position:0% +shift effect this e does not have to be +small okay and so this is the thing will + + align:start position:0% +small okay and so this is the thing will + + + align:start position:0% +small okay and so this is the thing will +be important + + align:start position:0% +be important + + + align:start position:0% +be important +here so + + align:start position:0% +here so + + + align:start position:0% +here so +when when R is much much greater than R + + align:start position:0% +when when R is much much greater than R + + + align:start position:0% +when when R is much much greater than R +so when we are sitting around + + align:start position:0% +so when we are sitting around + + + align:start position:0% +so when we are sitting around +here when we are sitting around + + align:start position:0% +here when we are sitting around + + + align:start position:0% +here when we are sitting around +here then H is + + align:start position:0% +here then H is + + + align:start position:0% +here then H is +one okay then then the limit e s here + + align:start position:0% +one okay then then the limit e s here + + + align:start position:0% +one okay then then the limit e s here +Alpha Prime goes + + align:start position:0% +Alpha Prime goes + + + align:start position:0% +Alpha Prime goes +zero really just tells you that all + + align:start position:0% +zero really just tells you that all + + + align:start position:0% +zero really just tells you that all +massive close + + align:start position:0% + + + + align:start position:0% + +couple + + align:start position:0% +couple + + + align:start position:0% +couple +okay in + + align:start position:0% +okay in + + + align:start position:0% +okay in +particular in particular the the + + align:start position:0% +particular in particular the the + + + align:start position:0% +particular in particular the the +inaction more closing themselves by the + + align:start position:0% +inaction more closing themselves by the + + + align:start position:0% +inaction more closing themselves by the +same argument they also become weaker + + align:start position:0% +same argument they also become weaker + + + align:start position:0% +same argument they also become weaker +and weaker when you go to low limit so + + align:start position:0% +and weaker when you go to low limit so + + + align:start position:0% +and weaker when you go to low limit so +essentially again they become free + + align:start position:0% +essentially again they become free + + + align:start position:0% +essentially again they become free +gravitons + + align:start position:0% + + + + align:start position:0% + +okay but now let's look + + align:start position:0% +okay but now let's look + + + align:start position:0% +okay but now let's look +at but now let's look at the other + + align:start position:0% +at but now let's look at the other + + + align:start position:0% +at but now let's look at the other +regime and R around here + + align:start position:0% +regime and R around here + + + align:start position:0% +regime and R around here +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +now so this is for that so for but now + + align:start position:0% +now so this is for that so for but now + + + align:start position:0% +now so this is for that so for but now +for let's consider R smaller than r + + align:start position:0% +for let's consider R smaller than r + + + align:start position:0% +for let's consider R smaller than r +capital r and then in this regime we go + + align:start position:0% +capital r and then in this regime we go + + + align:start position:0% +capital r and then in this regime we go +to this ad S5 * S5 then H become R to + + align:start position:0% +to this ad S5 * S5 then H become R to + + + align:start position:0% +to this ad S5 * S5 then H become R to +the^ 4 + + align:start position:0% +the^ 4 + + + align:start position:0% +the^ 4 +R4 and now this + + align:start position:0% + + + + align:start position:0% + +statement and the E Square Alpha Prime + + align:start position:0% +statement and the E Square Alpha Prime + + + align:start position:0% +statement and the E Square Alpha Prime +go to zero translate now you have red + + align:start position:0% +go to zero translate now you have red + + + align:start position:0% +go to zero translate now you have red +shift Factor eal square if I translate + + align:start position:0% +shift Factor eal square if I translate + + + align:start position:0% +shift Factor eal square if I translate +inal the local energy scale + + align:start position:0% + + + + align:start position:0% + +okay in particular now let's remember + + align:start position:0% +okay in particular now let's remember + + + align:start position:0% +okay in particular now let's remember +this R square is R4 is given by that so + + align:start position:0% +this R square is R4 is given by that so + + + align:start position:0% +this R square is R4 is given by that so +this can be + + align:start position:0% +this can be + + + align:start position:0% +this can be +written e t Square + + align:start position:0% + + + + align:start position:0% + +r² 4 Pi + + align:start position:0% +r² 4 Pi + + + align:start position:0% +r² 4 Pi +GSN goes to + + align:start position:0% + + + + align:start position:0% + +zero so now important thing + + align:start position:0% +zero so now important thing + + + align:start position:0% +zero so now important thing +happened important thing just happened + + align:start position:0% +happened important thing just happened + + + align:start position:0% +happened important thing just happened +then you find this Alpha Prime actually + + align:start position:0% +then you find this Alpha Prime actually + + + align:start position:0% +then you find this Alpha Prime actually +cancel with each other Alpha Prime here + + align:start position:0% +cancel with each other Alpha Prime here + + + align:start position:0% +cancel with each other Alpha Prime here +and Alpha Prime there they cancel each + + align:start position:0% +and Alpha Prime there they cancel each + + + align:start position:0% +and Alpha Prime there they cancel each +other and here there's nothing off Prime + + align:start position:0% +other and here there's nothing off Prime + + + align:start position:0% +other and here there's nothing off Prime +left okay so when you take this limit + + align:start position:0% + + + + align:start position:0% + +when you take this limit and uh it's so + + align:start position:0% +when you take this limit and uh it's so + + + align:start position:0% +when you take this limit and uh it's so +then this become this quantity goes to + + align:start position:0% +then this become this quantity goes to + + + align:start position:0% +then this become this quantity goes to +zero and now + + align:start position:0% +zero and now + + + align:start position:0% +zero and now +eow can actually be + + align:start position:0% +eow can actually be + + + align:start position:0% +eow can actually be +anything as far as R sufficiently small + + align:start position:0% +anything as far as R sufficiently small + + + align:start position:0% +anything as far as R sufficiently small +okay so that means for any + + align:start position:0% + + + + align:start position:0% + +eal you can even have huge energy noal + + align:start position:0% +eal you can even have huge energy noal + + + align:start position:0% +eal you can even have huge energy noal +proper energy + + align:start position:0% + + + + align:start position:0% + +you can satisfy the L + + align:start position:0% + + + + align:start position:0% + +limit if those modes leave at R very + + align:start position:0% +limit if those modes leave at R very + + + align:start position:0% +limit if those modes leave at R very +close to + + align:start position:0% +close to + + + align:start position:0% +close to +zero means that they they leave on this + + align:start position:0% +zero means that they they leave on this + + + align:start position:0% +zero means that they they leave on this +throat deep + + align:start position:0% +throat deep + + + align:start position:0% +throat deep +enough so this is very + + align:start position:0% +enough so this is very + + + align:start position:0% +enough so this is very +simple physically this is very + + align:start position:0% +simple physically this is very + + + align:start position:0% +simple physically this is very +simple because of this curved space + + align:start position:0% +simple because of this curved space + + + align:start position:0% +simple because of this curved space +effect because of H this curve space + + align:start position:0% +effect because of H this curve space + + + align:start position:0% +effect because of H this curve space +effect there's a huge amount of red + + align:start position:0% +effect there's a huge amount of red + + + align:start position:0% +effect there's a huge amount of red +shift between here and there between the + + align:start position:0% +shift between here and there between the + + + align:start position:0% +shift between here and there between the +local prob time here and there very big + + align:start position:0% +local prob time here and there very big + + + align:start position:0% +local prob time here and there very big +energy + + align:start position:0% +energy + + + align:start position:0% +energy +here build from here can become very + + align:start position:0% +here build from here can become very + + + align:start position:0% +here build from here can become very +very + + align:start position:0% +very + + + align:start position:0% +very +small in particular you go deeper into + + align:start position:0% +small in particular you go deeper into + + + align:start position:0% +small in particular you go deeper into +this + + align:start position:0% +this + + + align:start position:0% +this +throat the red shift factor is bigger so + + align:start position:0% +throat the red shift factor is bigger so + + + align:start position:0% +throat the red shift factor is bigger so +no matter how large the + + align:start position:0% +no matter how large the + + + align:start position:0% +no matter how large the +energy if you go deeper enough deep + + align:start position:0% +energy if you go deeper enough deep + + + align:start position:0% +energy if you go deeper enough deep +enough we always appear within a Lage + + align:start position:0% +enough we always appear within a Lage + + + align:start position:0% +enough we always appear within a Lage +limit here + + align:start position:0% +limit here + + + align:start position:0% +limit here +okay okay so that means when you sit + + align:start position:0% +okay okay so that means when you sit + + + align:start position:0% +okay okay so that means when you sit +deep + + align:start position:0% +deep + + + align:start position:0% +deep +enough then actually anything is + + align:start position:0% + + + + align:start position:0% + +a including a massive stream mode + + align:start position:0% +a including a massive stream mode + + + align:start position:0% +a including a massive stream mode +okay including massive stream mode so + + align:start position:0% +okay including massive stream mode so + + + align:start position:0% +okay including massive stream mode so +now we remember when you go I go to Z + + align:start position:0% +now we remember when you go I go to Z + + + align:start position:0% +now we remember when you go I go to Z +essentially you get this ads 5 time + + align:start position:0% + + + + align:start position:0% + +S5 so in I equal to Z we just get this + + align:start position:0% +S5 so in I equal to Z we just get this + + + align:start position:0% +S5 so in I equal to Z we just get this +geometry which is a is five times so + + align:start position:0% +geometry which is a is five times so + + + align:start position:0% +geometry which is a is five times so +it's five so now what we find is that in + + align:start position:0% +it's five so now what we find is that in + + + align:start position:0% +it's five so now what we find is that in +the ler m in the + + align:start position:0% + + + + align:start position:0% + +B we get three + + align:start position:0% + + + + align:start position:0% + +gravitons and I to + + align:start position:0% +gravitons and I to + + + align:start position:0% +gravitons and I to +Infinity + + align:start position:0% +Infinity + + + align:start position:0% +Infinity +and then + + align:start position:0% +and then + + + align:start position:0% +and then +plus full string + + align:start position:0% + + + + align:start position:0% + +theory in is five times is + + align:start position:0% + + + + align:start position:0% + +five + + align:start position:0% + + + + align:start position:0% + +okay F so so um + + align:start position:0% + + + + align:start position:0% + +yeah and again the two SE is decouple + + align:start position:0% +yeah and again the two SE is decouple + + + align:start position:0% +yeah and again the two SE is decouple +because when you take the L limit then + + align:start position:0% +because when you take the L limit then + + + align:start position:0% +because when you take the L limit then +those then those string mode have to + + align:start position:0% +those then those string mode have to + + + align:start position:0% +those then those string mode have to +leave very far + + align:start position:0% +leave very far + + + align:start position:0% +leave very far +down in this throat and then they have + + align:start position:0% +down in this throat and then they have + + + align:start position:0% +down in this throat and then they have +low overlap with the graviton and leave + + align:start position:0% +low overlap with the graviton and leave + + + align:start position:0% +low overlap with the graviton and leave +at Infinity okay and have over with gra + + align:start position:0% +at Infinity okay and have over with gra + + + align:start position:0% +at Infinity okay and have over with gra +yes so I'm confused about the way that + + align:start position:0% +yes so I'm confused about the way that + + + align:start position:0% +yes so I'm confused about the way that +you wrot that so you say three so + + align:start position:0% +you wrot that so you say three so + + + align:start position:0% +you wrot that so you say three so +there's three gravitons that are + + align:start position:0% +there's three gravitons that are + + + align:start position:0% +there's three gravitons that are +Infinity but also full string theory in + + align:start position:0% +Infinity but also full string theory in + + + align:start position:0% +Infinity but also full string theory in +the last but doesn't full String Theory + + align:start position:0% +the last but doesn't full String Theory + + + align:start position:0% +the last but doesn't full String Theory +include gravitons no no no yeah yeah + + align:start position:0% +include gravitons no no no yeah yeah + + + align:start position:0% +include gravitons no no no yeah yeah +this is the uh uh this is a full there's + + align:start position:0% +this is the uh uh this is a full there's + + + align:start position:0% +this is the uh uh this is a full there's +some different graviton in ads 5 * + + align:start position:0% +some different graviton in ads 5 * + + + align:start position:0% +some different graviton in ads 5 * +S5 I'm say full stren Ser in ads 5 * S5 + + align:start position:0% +S5 I'm say full stren Ser in ads 5 * S5 + + + align:start position:0% +S5 I'm say full stren Ser in ads 5 * S5 +those those are not fre minkovski space + + align:start position:0% +those those are not fre minkovski space + + + align:start position:0% +those those are not fre minkovski space +graviton this is minkovski space + + align:start position:0% +graviton this is minkovski space + + + align:start position:0% +graviton this is minkovski space +graviton so this is minkovsky space + + align:start position:0% +graviton so this is minkovsky space + + + align:start position:0% +graviton so this is minkovsky space +gra and things which live + + align:start position:0% + + + + align:start position:0% + +here the nature are very + + align:start position:0% +here the nature are very + + + align:start position:0% +here the nature are very +different yeah okay yes full String + + align:start position:0% +different yeah okay yes full String + + + align:start position:0% +different yeah okay yes full String +Theory only for closed strings only + + align:start position:0% +Theory only for closed strings only + + + align:start position:0% +Theory only for closed strings only +closed string there's no open string in + + align:start position:0% +closed string there's no open string in + + + align:start position:0% +closed string there's no open string in +this picture there only closed + + align:start position:0% + + + + align:start position:0% + +strings + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +sorry no no there's no AR that's what I + + align:start position:0% +sorry no no there's no AR that's what I + + + align:start position:0% +sorry no no there's no AR that's what I +just explained those free gra leave here + + align:start position:0% +just explained those free gra leave here + + + align:start position:0% +just explained those free gra leave here +and string leave infinite down the + + align:start position:0% +and string leave infinite down the + + + align:start position:0% +and string leave infinite down the +throat throat in the low limit they they + + align:start position:0% +throat throat in the low limit they they + + + align:start position:0% +throat throat in the low limit they they +infinite they INF they + + align:start position:0% + + + + align:start position:0% + +essentially as not proper distance you + + align:start position:0% +essentially as not proper distance you + + + align:start position:0% +essentially as not proper distance you +want to separate them depend on how low + + align:start position:0% +want to separate them depend on how low + + + align:start position:0% +want to separate them depend on how low +energy you want to + + align:start position:0% + + + + align:start position:0% + +go yeah I'm just saying when you take + + align:start position:0% +go yeah I'm just saying when you take + + + align:start position:0% +go yeah I'm just saying when you take +the low + + align:start position:0% +the low + + + align:start position:0% +the low +limit when you take the lower limit then + + align:start position:0% +limit when you take the lower limit then + + + align:start position:0% +limit when you take the lower limit then +the separation separation then become + + align:start position:0% + + + + align:start position:0% + +infinite no they have nothing to do with + + align:start position:0% +infinite no they have nothing to do with + + + align:start position:0% +infinite no they have nothing to do with +each + + align:start position:0% +each + + + align:start position:0% +each +other geographically they live one is in + + align:start position:0% +other geographically they live one is in + + + align:start position:0% +other geographically they live one is in +the this side of the Galaxy the other is + + align:start position:0% +the this side of the Galaxy the other is + + + align:start position:0% +the this side of the Galaxy the other is +living on the other side the C they have + + align:start position:0% +living on the other side the C they have + + + align:start position:0% +living on the other side the C they have +low the wave function have low overlap + + align:start position:0% +low the wave function have low overlap + + + align:start position:0% +low the wave function have low overlap +with each + + align:start position:0% + + + + align:start position:0% + +other + + align:start position:0% + + + + align:start position:0% + +could + + align:start position:0% +could + + + align:start position:0% +could +something yeah I'm just saying when you + + align:start position:0% +something yeah I'm just saying when you + + + align:start position:0% +something yeah I'm just saying when you +take the L + + align:start position:0% +take the L + + + align:start position:0% +take the L +limit then the only mode which can + + align:start position:0% +limit then the only mode which can + + + align:start position:0% +limit then the only mode which can +survive other than the masses mode which + + align:start position:0% +survive other than the masses mode which + + + align:start position:0% +survive other than the masses mode which +live around here just fin energy mode + + align:start position:0% +live around here just fin energy mode + + + align:start position:0% +live around here just fin energy mode +they cannot leave in this + + align:start position:0% + + + + align:start position:0% + +place yeah do the string theory on ad I + + align:start position:0% +place yeah do the string theory on ad I + + + align:start position:0% +place yeah do the string theory on ad I +see the flock as well yeah yeah yeah + + align:start position:0% +see the flock as well yeah yeah yeah + + + align:start position:0% +see the flock as well yeah yeah yeah +yeah flock yeah yeah with the flux yeah + + align:start position:0% + + + + align:start position:0% + +okay then this two sectors should de + + align:start position:0% + + + + align:start position:0% + +couple so now we have + + align:start position:0% + + + + align:start position:0% + +derived so from this a equal to + + align:start position:0% + + + + align:start position:0% + +B then we take the L energy + + align:start position:0% +B then we take the L energy + + + align:start position:0% +B then we take the L energy +limit so here we we have in + + align:start position:0% + + + + align:start position:0% + +plus three + + align:start position:0% + + + + align:start position:0% + +graviton and here you have tpe Tob + + align:start position:0% + + + + align:start position:0% + +string S5 * + + align:start position:0% + + + + align:start position:0% + +S5 plus three + + align:start position:0% + + + + align:start position:0% + +gra + + align:start position:0% +gra + + + align:start position:0% +gra +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and the free gravit part is the + + align:start position:0% +and the free gravit part is the + + + align:start position:0% +and the free gravit part is the +same then you conclude and they they're + + align:start position:0% +same then you conclude and they they're + + + align:start position:0% +same then you conclude and they they're +just free and the inac in part of both + + align:start position:0% +just free and the inac in part of both + + + align:start position:0% +just free and the inac in part of both +sides then then you just equate them you + + align:start position:0% +sides then then you just equate them you + + + align:start position:0% +sides then then you just equate them you +find force + + align:start position:0% + + + + align:start position:0% + +M with un + + align:start position:0% + + + + align:start position:0% + +n then is equal to type to be + + align:start position:0% + + + + align:start position:0% + +string this five just + + align:start position:0% + + + + align:start position:0% + +F so this was a surprising statement + + align:start position:0% +F so this was a surprising statement + + + align:start position:0% +F so this was a surprising statement +saying a equal to + + align:start position:0% +saying a equal to + + + align:start position:0% +saying a equal to +B But A and B are both say complicated + + align:start position:0% +B But A and B are both say complicated + + + align:start position:0% +B But A and B are both say complicated +object both are complicated object but + + align:start position:0% +object both are complicated object but + + + align:start position:0% +object both are complicated object but +now when we take the L range limit and + + align:start position:0% +now when we take the L range limit and + + + align:start position:0% +now when we take the L range limit and +then one side then you reach something + + align:start position:0% +then one side then you reach something + + + align:start position:0% +then one side then you reach something +very surprising because on this side + + align:start position:0% +very surprising because on this side + + + align:start position:0% +very surprising because on this side +there's no + + align:start position:0% +there's no + + + align:start position:0% +there's no +gravity on this side there's no gravity + + align:start position:0% +gravity on this side there's no gravity + + + align:start position:0% +gravity on this side there's no gravity +but this side is a full String Theory so + + align:start position:0% +but this side is a full String Theory so + + + align:start position:0% +but this side is a full String Theory so +now you equate some field Theory with a + + align:start position:0% +now you equate some field Theory with a + + + align:start position:0% +now you equate some field Theory with a +full String + + align:start position:0% +full String + + + align:start position:0% +full String +Theory + + align:start position:0% + + + + align:start position:0% + +okay yes so the the super Yang Mills is + + align:start position:0% +okay yes so the the super Yang Mills is + + + align:start position:0% +okay yes so the the super Yang Mills is +living just on the D3 brain yeah okay + + align:start position:0% + + + + align:start position:0% + +any questions regarding + + align:start position:0% +any questions regarding + + + align:start position:0% +any questions regarding +this so for example when + + align:start position:0% +this so for example when + + + align:start position:0% +this so for example when +Ral R is + + align:start position:0% +Ral R is + + + align:start position:0% +Ral R is +also yeah this yeah yeah but that's + + align:start position:0% +also yeah this yeah yeah but that's + + + align:start position:0% +also yeah this yeah yeah but that's +always F at proper distance away they + + align:start position:0% +always F at proper distance away they + + + align:start position:0% +always F at proper distance away they +always file at the proper distance so + + align:start position:0% +always file at the proper distance so + + + align:start position:0% +always file at the proper distance so +the key is that when you talk about the + + align:start position:0% +the key is that when you talk about the + + + align:start position:0% +the key is that when you talk about the +general + + align:start position:0% +general + + + align:start position:0% +general +mode uh uh uh you can anything you talk + + align:start position:0% +mode uh uh uh you can anything you talk + + + align:start position:0% +mode uh uh uh you can anything you talk +about is f distance way we taking a + + align:start position:0% +about is f distance way we taking a + + + align:start position:0% +about is f distance way we taking a +limit here this is going to Infinity + + align:start position:0% +limit here this is going to Infinity + + + align:start position:0% +limit here this is going to Infinity +you're leaving infinite down the throat + + align:start position:0% +you're leaving infinite down the throat + + + align:start position:0% +you're leaving infinite down the throat +anything fin is free H yeah + + align:start position:0% + + + + align:start position:0% + +anything when you talk about the finite + + align:start position:0% +anything when you talk about the finite + + + align:start position:0% +anything when you talk about the finite +energy then the story is always + + align:start position:0% +energy then the story is always + + + align:start position:0% +energy then the story is always +complicated and uh then all this + + align:start position:0% +complicated and uh then all this + + + align:start position:0% +complicated and uh then all this +geometry will matter and and the thing + + align:start position:0% +geometry will matter and and the thing + + + align:start position:0% +geometry will matter and and the thing +only become simple you really take the E + + align:start position:0% +only become simple you really take the E + + + align:start position:0% +only become simple you really take the E +go to zero limit and it's the same thing + + align:start position:0% +go to zero limit and it's the same thing + + + align:start position:0% +go to zero limit and it's the same thing +here same thing in this picture when we + + align:start position:0% +here same thing in this picture when we + + + align:start position:0% +here same thing in this picture when we +say you go to the in for Super Y + + align:start position:0% +say you go to the in for Super Y + + + align:start position:0% +say you go to the in for Super Y +you always have to take that limit e + + align:start position:0% +you always have to take that limit e + + + align:start position:0% +you always have to take that limit e +goes to zero limit then you completely + + align:start position:0% +goes to zero limit then you completely + + + align:start position:0% +goes to zero limit then you completely +decouple the other things because any + + align:start position:0% +decouple the other things because any + + + align:start position:0% +decouple the other things because any +tiny tiny long z e there's always some + + align:start position:0% +tiny tiny long z e there's always some + + + align:start position:0% +tiny tiny long z e there's always some +gravity left so you really really have + + align:start position:0% +gravity left so you really really have + + + align:start position:0% +gravity left so you really really have +to take that energy go to zero limit and + + align:start position:0% +to take that energy go to zero limit and + + + align:start position:0% +to take that energy go to zero limit and +then you rescale the energy to be finite + + align:start position:0% +then you rescale the energy to be finite + + + align:start position:0% +then you rescale the energy to be finite +you understand what I mean you always + + align:start position:0% +you understand what I mean you always + + + align:start position:0% +you understand what I mean you always +have to take that singular limit it's + + align:start position:0% +have to take that singular limit it's + + + align:start position:0% +have to take that singular limit it's +just like when you take the in the C you + + align:start position:0% +just like when you take the in the C you + + + align:start position:0% +just like when you take the in the C you +have to take the infinite volume limit + + align:start position:0% +have to take the infinite volume limit + + + align:start position:0% +have to take the infinite volume limit +and then Things become simple and and + + align:start position:0% +and then Things become simple and and + + + align:start position:0% +and then Things become simple and and +here it's the same thing + + align:start position:0% +here it's the same thing + + + align:start position:0% +here it's the same thing +yeah whenever you have some finite + + align:start position:0% +yeah whenever you have some finite + + + align:start position:0% +yeah whenever you have some finite +energy they always some call some + + align:start position:0% +energy they always some call some + + + align:start position:0% +energy they always some call some +component between + + align:start position:0% + + + + align:start position:0% + +them good so do you want to have a break + + align:start position:0% +them good so do you want to have a break + + + align:start position:0% +them good so do you want to have a break +this is like a FIS guas that some how + + align:start position:0% +this is like a FIS guas that some how + + + align:start position:0% +this is like a FIS guas that some how +these two must be the same + + align:start position:0% +these two must be the same + + + align:start position:0% +these two must be the same +okay these two must be the same so so + + align:start position:0% +okay these two must be the same so so + + + align:start position:0% +okay these two must be the same so so +this is a surprising statement because + + align:start position:0% +this is a surprising statement because + + + align:start position:0% +this is a surprising statement because +the uh because on the one side it's a + + align:start position:0% +the uh because on the one side it's a + + + align:start position:0% +the uh because on the one side it's a +field Theory and and the other side is + + align:start position:0% +field Theory and and the other side is + + + align:start position:0% +field Theory and and the other side is +full gravity + + align:start position:0% +full gravity + + + align:start position:0% +full gravity +Ser so so you said that in principle you + + align:start position:0% +Ser so so you said that in principle you + + + align:start position:0% +Ser so so you said that in principle you +can generalize this distribution for any + + align:start position:0% +can generalize this distribution for any + + + align:start position:0% +can generalize this distribution for any +matric in the full Str the for any reg + + align:start position:0% +matric in the full Str the for any reg + + + align:start position:0% +matric in the full Str the for any reg +yeah but in that case maybe you will not + + align:start position:0% +yeah but in that case maybe you will not + + + align:start position:0% +yeah but in that case maybe you will not +probably not get Geometry as same as + + align:start position:0% +probably not get Geometry as same as + + + align:start position:0% +probably not get Geometry as same as +adh5 oh yeah that's a very good question + + align:start position:0% +adh5 oh yeah that's a very good question + + + align:start position:0% +adh5 oh yeah that's a very good question +uh uh that's a very good question it it + + align:start position:0% +uh uh that's a very good question it it + + + align:start position:0% +uh uh that's a very good question it it +turns out in indeed logically you you + + align:start position:0% +turns out in indeed logically you you + + + align:start position:0% +turns out in indeed logically you you +may not but the uh uh but actually S5 * + + align:start position:0% +may not but the uh uh but actually S5 * + + + align:start position:0% +may not but the uh uh but actually S5 * +S5 is a highly I as I will explain it's + + align:start position:0% +S5 is a highly I as I will explain it's + + + align:start position:0% +S5 is a highly I as I will explain it's +a very highly symmetric space it turns + + align:start position:0% +a very highly symmetric space it turns + + + align:start position:0% +a very highly symmetric space it turns +out + + align:start position:0% +out + + + align:start position:0% +out +actually it is exact stre the at least + + align:start position:0% +actually it is exact stre the at least + + + align:start position:0% +actually it is exact stre the at least +we believe is exact stren series + + align:start position:0% +we believe is exact stren series + + + align:start position:0% +we believe is exact stren series +geometry and when you include all those + + align:start position:0% +geometry and when you include all those + + + align:start position:0% +geometry and when you include all those +corre this will not + + align:start position:0% + + + + align:start position:0% + +change yes so so with this in mind that + + align:start position:0% +change yes so so with this in mind that + + + align:start position:0% +change yes so so with this in mind that +means that people don't they only know + + align:start position:0% +means that people don't they only know + + + align:start position:0% +means that people don't they only know +this juristically yeah so there's no + + align:start position:0% +this juristically yeah so there's no + + + align:start position:0% +this juristically yeah so there's no +actual like proof of this besides the + + align:start position:0% +actual like proof of this besides the + + + align:start position:0% +actual like proof of this besides the +fact that everyone believes it works + + align:start position:0% +fact that everyone believes it works + + + align:start position:0% +fact that everyone believes it works +yeah depend on what you the level what + + align:start position:0% +yeah depend on what you the level what + + + align:start position:0% +yeah depend on what you the level what +do you mean it + + align:start position:0% +do you mean it + + + align:start position:0% +do you mean it +works so uh so the physicist way it + + align:start position:0% +works so uh so the physicist way it + + + align:start position:0% +works so uh so the physicist way it +works is that one works two works yeah + + align:start position:0% +works is that one works two works yeah + + + align:start position:0% +works is that one works two works yeah +inity one works in two Works in three + + align:start position:0% +inity one works in two Works in three + + + align:start position:0% +inity one works in two Works in three +Works in four works then we say it works + + align:start position:0% +Works in four works then we say it works + + + align:start position:0% +Works in four works then we say it works +and uh and this have way past that so + + align:start position:0% +and uh and this have way past that so + + + align:start position:0% +and uh and this have way past that so +maybe this worked to until the 10,000 + + align:start position:0% +maybe this worked to until the 10,000 + + + align:start position:0% +maybe this worked to until the 10,000 +something like that but it's not the + + align:start position:0% +something like that but it's not the + + + align:start position:0% +something like that but it's not the +proof sure yeah but worked until the + + align:start position:0% +proof sure yeah but worked until the + + + align:start position:0% +proof sure yeah but worked until the +10,000 something like that + + align:start position:0% + + + + align:start position:0% + +yeah okay good so uh so now let's talk + + align:start position:0% +yeah okay good so uh so now let's talk + + + align:start position:0% +yeah okay good so uh so now let's talk +about this + + align:start position:0% +about this + + + align:start position:0% +about this +Duality so this is normally called adsf + + align:start position:0% + + + + align:start position:0% + +Duality + + align:start position:0% +Duality + + + align:start position:0% +Duality +okay uh + + align:start position:0% +okay uh + + + align:start position:0% +okay uh +um so so to understand this D let's + + align:start position:0% +um so so to understand this D let's + + + align:start position:0% +um so so to understand this D let's +first uh understand the object in this + + align:start position:0% +first uh understand the object in this + + + align:start position:0% +first uh understand the object in this +relation okay so let me just say a + + align:start position:0% +relation okay so let me just say a + + + align:start position:0% +relation okay so let me just say a +little bit about the object in this + + align:start position:0% +little bit about the object in this + + + align:start position:0% +little bit about the object in this +relation first let me say a little bit + + align:start position:0% +relation first let me say a little bit + + + align:start position:0% +relation first let me say a little bit +about anti space since the um uh + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% + + + + align:start position:0% + +um since that may not be something + + align:start position:0% +um since that may not be something + + + align:start position:0% +um since that may not be something +something you have worked + + align:start position:0% +something you have worked + + + align:start position:0% +something you have worked +before + + align:start position:0% +before + + + align:start position:0% +before +um okay so so one way to write the + + align:start position:0% +um okay so so one way to write the + + + align:start position:0% +um okay so so one way to write the +Matrix is this Matrix so this is ads5 + + align:start position:0% +Matrix is this Matrix so this is ads5 + + + align:start position:0% +Matrix is this Matrix so this is ads5 +so this is ADS 5 okay so this is ADS 5 + + align:start position:0% +so this is ADS 5 okay so this is ADS 5 + + + align:start position:0% +so this is ADS 5 okay so this is ADS 5 +magic uh uh so so the yeah you can + + align:start position:0% +magic uh uh so so the yeah you can + + + align:start position:0% +magic uh uh so so the yeah you can +actually write it as ads yeah let me + + align:start position:0% +actually write it as ads yeah let me + + + align:start position:0% +actually write it as ads yeah let me +just copy it down so you can generalize + + align:start position:0% +just copy it down so you can generalize + + + align:start position:0% +just copy it down so you can generalize +to any number of + + align:start position:0% +to any number of + + + align:start position:0% +to any number of +Dimensions you can generate number any + + align:start position:0% +Dimensions you can generate number any + + + align:start position:0% +Dimensions you can generate number any +number of + + align:start position:0% +number of + + + align:start position:0% +number of +Dimensions if we make if you make this + + align:start position:0% +Dimensions if we make if you make this + + + align:start position:0% +Dimensions if we make if you make this +part into a d dimensional minkovsky + + align:start position:0% +part into a d dimensional minkovsky + + + align:start position:0% +part into a d dimensional minkovsky +space + + align:start position:0% +space + + + align:start position:0% +space +time + + align:start position:0% +time + + + align:start position:0% +time +okay and + + align:start position:0% + + + + align:start position:0% + +then then this would be the matric of + + align:start position:0% +then then this would be the matric of + + + align:start position:0% +then then this would be the matric of +ads say d+1 Dimension so this is a d d + + align:start position:0% +ads say d+1 Dimension so this is a d d + + + align:start position:0% +ads say d+1 Dimension so this is a d d +plus y Dimension movi then you have a + + align:start position:0% +plus y Dimension movi then you have a + + + align:start position:0% +plus y Dimension movi then you have a +lot R Direction so uh so let me call + + align:start position:0% +lot R Direction so uh so let me call + + + align:start position:0% +lot R Direction so uh so let me call +this + + align:start position:0% +this + + + align:start position:0% +this +my my uh so now let me relabel this to + + align:start position:0% +my my uh so now let me relabel this to + + + align:start position:0% +my my uh so now let me relabel this to +be one + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so so R can be as a curvature radius of + + align:start position:0% +so so R can be as a curvature radius of + + + align:start position:0% +so so R can be as a curvature radius of +this space time so this I is a constant + + align:start position:0% +this space time so this I is a constant + + + align:start position:0% +this space time so this I is a constant +and + + align:start position:0% +and + + + align:start position:0% +and +this this radius R goes from zero to + + align:start position:0% +this this radius R goes from zero to + + + align:start position:0% +this this radius R goes from zero to +Infinity + + align:start position:0% +Infinity + + + align:start position:0% +Infinity +okay R goes Zero from Infinity so + + align:start position:0% +okay R goes Zero from Infinity so + + + align:start position:0% +okay R goes Zero from Infinity so +roughly a geometric picture here is that + + align:start position:0% +roughly a geometric picture here is that + + + align:start position:0% +roughly a geometric picture here is that +so you can see that you have half + + align:start position:0% +so you can see that you have half + + + align:start position:0% +so you can see that you have half +space okay you have a half space r from + + align:start position:0% +space okay you have a half space r from + + + align:start position:0% +space okay you have a half space r from +zero to + + align:start position:0% + + + + align:start position:0% + +infinity and uh and at each value of + + align:start position:0% + + + + align:start position:0% + +r at each value of R there's movi space + + align:start position:0% +r at each value of R there's movi space + + + align:start position:0% +r at each value of R there's movi space +time there D dimensional movy space time + + align:start position:0% +time there D dimensional movy space time + + + align:start position:0% +time there D dimensional movy space time +so if you fix R then you just get some D + + align:start position:0% +so if you fix R then you just get some D + + + align:start position:0% +so if you fix R then you just get some D +dimensional movi space time and uh and + + align:start position:0% +dimensional movi space time and uh and + + + align:start position:0% +dimensional movi space time and uh and +with some prefactor to define the scale + + align:start position:0% +with some prefactor to define the scale + + + align:start position:0% +with some prefactor to define the scale +of the movi space time okay so so just + + align:start position:0% +of the movi space time okay so so just + + + align:start position:0% +of the movi space time okay so so just +like this it's a it's a you have half + + align:start position:0% +like this it's a it's a you have half + + + align:start position:0% +like this it's a it's a you have half +line are from zero to Infinity then at + + align:start position:0% +line are from zero to Infinity then at + + + align:start position:0% +line are from zero to Infinity then at +each point of this half line exfoliated + + align:start position:0% +each point of this half line exfoliated + + + align:start position:0% +each point of this half line exfoliated +by the dimensional movi space time so + + align:start position:0% +by the dimensional movi space time so + + + align:start position:0% +by the dimensional movi space time so +that essentially what this does so the + + align:start position:0% +that essentially what this does so the + + + align:start position:0% +that essentially what this does so the +key thing is that the movi time is what + + align:start position:0% +key thing is that the movi time is what + + + align:start position:0% +key thing is that the movi time is what +we normally call warped is that the the + + align:start position:0% +we normally call warped is that the the + + + align:start position:0% +we normally call warped is that the the +the the scale factor of this minkovski + + align:start position:0% +the the scale factor of this minkovski + + + align:start position:0% +the the scale factor of this minkovski +space time depend on where you + + align:start position:0% +space time depend on where you + + + align:start position:0% +space time depend on where you +sit in the in the in the radar Direction + + align:start position:0% +sit in the in the in the radar Direction + + + align:start position:0% +sit in the in the in the radar Direction +okay so this R we l call radar Direction + + align:start position:0% +okay so this R we l call radar Direction + + + align:start position:0% +okay so this R we l call radar Direction +it depend on where you see in the radio + + align:start position:0% +it depend on where you see in the radio + + + align:start position:0% +it depend on where you see in the radio +Direction so when you R go to Infinity + + align:start position:0% + + + + align:start position:0% + +at R go to + + align:start position:0% +at R go to + + + align:start position:0% +at R go to +Infinity the scale size become infinite + + align:start position:0% +Infinity the scale size become infinite + + + align:start position:0% +Infinity the scale size become infinite +so this would normally call it to be the + + align:start position:0% + + + + align:start position:0% + +boundary so this we call to be the + + align:start position:0% +boundary so this we call to be the + + + align:start position:0% +boundary so this we call to be the +boundary say say IAL Infinity we call to + + align:start position:0% +boundary say say IAL Infinity we call to + + + align:start position:0% +boundary say say IAL Infinity we call to +be the + + align:start position:0% +be the + + + align:start position:0% +be the +boundary of the space + + align:start position:0% +boundary of the space + + + align:start position:0% +boundary of the space +time so this is a similar to say when we + + align:start position:0% +time so this is a similar to say when we + + + align:start position:0% +time so this is a similar to say when we +say when we write them in uh you create + + align:start position:0% +say when we write them in uh you create + + + align:start position:0% +say when we write them in uh you create +a matric in this + + align:start position:0% +a matric in this + + + align:start position:0% +a matric in this +form when R goes to Infinity the sphere + + align:start position:0% +form when R goes to Infinity the sphere + + + align:start position:0% +form when R goes to Infinity the sphere +size become infinite and then this is + + align:start position:0% +size become infinite and then this is + + + align:start position:0% +size become infinite and then this is +essentially the SpaceTime boundary + + align:start position:0% +essentially the SpaceTime boundary + + + align:start position:0% +essentially the SpaceTime boundary +roughly and so this can be similarly + + align:start position:0% +roughly and so this can be similarly + + + align:start position:0% +roughly and so this can be similarly +understand that way + + align:start position:0% +understand that way + + + align:start position:0% +understand that way +okay so this ads is the space + + align:start position:0% +okay so this ads is the space + + + align:start position:0% +okay so this ads is the space +time ads is a space + + align:start position:0% +time ads is a space + + + align:start position:0% +time ads is a space +time + + align:start position:0% +time + + + align:start position:0% +time +of constant curvature constant negative + + align:start position:0% +of constant curvature constant negative + + + align:start position:0% +of constant curvature constant negative +curvature + + align:start position:0% + + + + align:start position:0% + +okay in fact this is the most symmetric + + align:start position:0% +okay in fact this is the most symmetric + + + align:start position:0% +okay in fact this is the most symmetric +SpaceTime of lective constant + + align:start position:0% +SpaceTime of lective constant + + + align:start position:0% +SpaceTime of lective constant +curvature so so uh you can easily + + align:start position:0% +curvature so so uh you can easily + + + align:start position:0% +curvature so so uh you can easily +check can easily check this satisfi the + + align:start position:0% +check can easily check this satisfi the + + + align:start position:0% +check can easily check this satisfi the +Einstein + + align:start position:0% +Einstein + + + align:start position:0% +Einstein +equation with the lative c modu constant + + align:start position:0% +equation with the lative c modu constant + + + align:start position:0% +equation with the lative c modu constant +so so you can easily check you satisfy + + align:start position:0% +so so you can easily check you satisfy + + + align:start position:0% +so so you can easily check you satisfy +the Einstein equation so now because now + + align:start position:0% +the Einstein equation so now because now + + + align:start position:0% +the Einstein equation so now because now +using this R you load this radius this + + align:start position:0% +using this R you load this radius this + + + align:start position:0% +using this R you load this radius this +curvature radius so now I will call my + + align:start position:0% +curvature radius so now I will call my + + + align:start position:0% +curvature radius so now I will call my +curvature tensor always using the script + + align:start position:0% +curvature tensor always using the script + + + align:start position:0% +curvature tensor always using the script +now now so also MN now refers to all + + align:start position:0% +now now so also MN now refers to all + + + align:start position:0% +now now so also MN now refers to all +directions in this uh + + align:start position:0% + + + + align:start position:0% + +ads so you can easily check and satisfy + + align:start position:0% +ads so you can easily check and satisfy + + + align:start position:0% +ads so you can easily check and satisfy +this Einstein equation with some Co modu + + align:start position:0% +this Einstein equation with some Co modu + + + align:start position:0% +this Einstein equation with some Co modu +constant and uh you you can just compute + + align:start position:0% +constant and uh you you can just compute + + + align:start position:0% +constant and uh you you can just compute +the uh it's easy to compute the curv of + + align:start position:0% +the uh it's easy to compute the curv of + + + align:start position:0% +the uh it's easy to compute the curv of +this guy so let me just write down the + + align:start position:0% +this guy so let me just write down the + + + align:start position:0% +this guy so let me just write down the +answer so yeah yeah first you can uh + + align:start position:0% +answer so yeah yeah first you can uh + + + align:start position:0% +answer so yeah yeah first you can uh +yeah you can compute the curvature of + + align:start position:0% +yeah you can compute the curvature of + + + align:start position:0% +yeah you can compute the curvature of +this guy you can just find the answer so + + align:start position:0% +this guy you can just find the answer so + + + align:start position:0% +this guy you can just find the answer so +you find + + align:start position:0% +you find + + + align:start position:0% +you find +the the curvature the rich scaler is + + align:start position:0% +the the curvature the rich scaler is + + + align:start position:0% +the the curvature the rich scaler is +given by minus D * D + 1 R + + align:start position:0% +given by minus D * D + 1 R + + + align:start position:0% +given by minus D * D + 1 R +square okay so so this is a rich scaler + + align:start position:0% +square okay so so this is a rich scaler + + + align:start position:0% +square okay so so this is a rich scaler +this R is the same as this is + + align:start position:0% +this R is the same as this is + + + align:start position:0% +this R is the same as this is +r and similarly you find the co modu + + align:start position:0% +r and similarly you find the co modu + + + align:start position:0% +r and similarly you find the co modu +constant then you can find here from is + + align:start position:0% +constant then you can find here from is + + + align:start position:0% +constant then you can find here from is +given by minus + + align:start position:0% +given by minus + + + align:start position:0% +given by minus +one2 D D minus one / + + align:start position:0% +one2 D D minus one / + + + align:start position:0% +one2 D D minus one / +r² sorry here should be minus + + align:start position:0% + + + + align:start position:0% + + + align:start position:0% + + + + align:start position:0% + +okay and I I said that this is the most + + align:start position:0% +okay and I I said that this is the most + + + align:start position:0% +okay and I I said that this is the most +symmetric + + align:start position:0% +symmetric + + + align:start position:0% +symmetric +homogeneous negative curvature space + + align:start position:0% +homogeneous negative curvature space + + + align:start position:0% +homogeneous negative curvature space +time so this is reflect it in that + + align:start position:0% +time so this is reflect it in that + + + align:start position:0% +time so this is reflect it in that +actually you can + + align:start position:0% +actually you can + + + align:start position:0% +actually you can +write the REM + + align:start position:0% + + + + align:start position:0% + +tensor the REM tensor of this space + + align:start position:0% +tensor the REM tensor of this space + + + align:start position:0% +tensor the REM tensor of this space +time purely in terms of this metric + + align:start position:0% +time purely in terms of this metric + + + align:start position:0% +time purely in terms of this metric +itself without using + + align:start position:0% + + + + align:start position:0% + +derivative + + align:start position:0% + + + + align:start position:0% + +okay so this is essentially definition + + align:start position:0% +okay so this is essentially definition + + + align:start position:0% +okay so this is essentially definition +of the uh the the most + + align:start position:0% +of the uh the the most + + + align:start position:0% +of the uh the the most +symmetric retive curvature space time is + + align:start position:0% +symmetric retive curvature space time is + + + align:start position:0% +symmetric retive curvature space time is +that the remman tensor can be written + + align:start position:0% +that the remman tensor can be written + + + align:start position:0% +that the remman tensor can be written +solely in terms of metric itself + + align:start position:0% + + + + align:start position:0% + +okay so these are just some fact of this + + align:start position:0% +okay so these are just some fact of this + + + align:start position:0% +okay so these are just some fact of this +uh uh um uh um + + align:start position:0% + + + + align:start position:0% + +space so so we often we use a lot of + + align:start position:0% +space so so we often we use a lot of + + + align:start position:0% +space so so we often we use a lot of +coordinates sometimes it's often + + align:start position:0% +coordinates sometimes it's often + + + align:start position:0% +coordinates sometimes it's often +convenient to + + align:start position:0% +convenient to + + + align:start position:0% +convenient to +use instead of using this + + align:start position:0% +use instead of using this + + + align:start position:0% +use instead of using this +R of using this R we will introduce + + align:start position:0% +R of using this R we will introduce + + + align:start position:0% +R of using this R we will introduce +another + + align:start position:0% + + + + align:start position:0% + +coordinate is introduce a z equal to r² + + align:start position:0% +coordinate is introduce a z equal to r² + + + align:start position:0% +coordinate is introduce a z equal to r² +divided by capital r squ divided by + + align:start position:0% +divided by capital r squ divided by + + + align:start position:0% +divided by capital r squ divided by +small R essentially just the 1 / + + align:start position:0% +small R essentially just the 1 / + + + align:start position:0% +small R essentially just the 1 / +R and because the capital r goes from + + align:start position:0% +R and because the capital r goes from + + + align:start position:0% +R and because the capital r goes from +zero to + + align:start position:0% +zero to + + + align:start position:0% +zero to +Infinity then small Z also going from + + align:start position:0% +Infinity then small Z also going from + + + align:start position:0% +Infinity then small Z also going from +zero to + + align:start position:0% +zero to + + + align:start position:0% +zero to +Infinity but now the + + align:start position:0% +Infinity but now the + + + align:start position:0% +Infinity but now the +boundary but now is equal to zero is the + + align:start position:0% + + + + align:start position:0% + +boundary rather than the equal to + + align:start position:0% +boundary rather than the equal to + + + align:start position:0% +boundary rather than the equal to +infinity and then the + + align:start position:0% +infinity and then the + + + align:start position:0% +infinity and then the +Matrix can be written in a slightly + + align:start position:0% +Matrix can be written in a slightly + + + align:start position:0% +Matrix can be written in a slightly +different way + + align:start position:0% +different way + + + align:start position:0% +different way +in terms of this Z + + align:start position:0% + + + + align:start position:0% + +coordinates you can read in this form + + align:start position:0% + + + + align:start position:0% + +okay the you can see the + + align:start position:0% + + + + align:start position:0% + +easyd so so again here you just change + + align:start position:0% +easyd so so again here you just change + + + align:start position:0% +easyd so so again here you just change +the label R by Z and Z equal to Z is the + + align:start position:0% +the label R by Z and Z equal to Z is the + + + align:start position:0% +the label R by Z and Z equal to Z is the +boundary and and going to Interior + + align:start position:0% +boundary and and going to Interior + + + align:start position:0% +boundary and and going to Interior +correspond to increase Z so Z + + align:start position:0% +correspond to increase Z so Z + + + align:start position:0% +correspond to increase Z so Z +corresponding to in the different + + align:start position:0% + + + + align:start position:0% + +direction + + align:start position:0% +direction + + + align:start position:0% +direction +okay previously in order to this + + align:start position:0% +okay previously in order to this + + + align:start position:0% +okay previously in order to this +HS we already assume the small R + + align:start position:0% +HS we already assume the small R + + + align:start position:0% +HS we already assume the small R +approach to Z yeah but here it + + align:start position:0% +approach to Z yeah but here it + + + align:start position:0% +approach to Z yeah but here it +can yeah that's a very good question uh + + align:start position:0% +can yeah that's a very good question uh + + + align:start position:0% +can yeah that's a very good question uh +I'm waiting for for for some of you to + + align:start position:0% +I'm waiting for for for some of you to + + + align:start position:0% +I'm waiting for for for some of you to +ask so so this is the + + align:start position:0% +ask so so this is the + + + align:start position:0% +ask so so this is the +uh so this is the uh uh the fysic is + + align:start position:0% +uh so this is the uh uh the fysic is + + + align:start position:0% +uh so this is the uh uh the fysic is +Magic which we um uh uh described yeah + + align:start position:0% +Magic which we um uh uh described yeah + + + align:start position:0% +Magic which we um uh uh described yeah +this is the fysic is magic so + + align:start position:0% +this is the fysic is magic so + + + align:start position:0% +this is the fysic is magic so +um yeah let me just say this way + + align:start position:0% + + + + align:start position:0% + +um so you have infinite + + align:start position:0% + + + + align:start position:0% + +Ro so we uh going to learn you should + + align:start position:0% +Ro so we uh going to learn you should + + + align:start position:0% +Ro so we uh going to learn you should +just go very much down in the throat + + align:start position:0% +just go very much down in the throat + + + align:start position:0% +just go very much down in the throat +okay but once you go down very once you + + align:start position:0% +okay but once you go down very once you + + + align:start position:0% +okay but once you go down very once you +decouple those descrip Freedom then you + + align:start position:0% +decouple those descrip Freedom then you + + + align:start position:0% +decouple those descrip Freedom then you +can just rescale your energy scale uh + + align:start position:0% +can just rescale your energy scale uh + + + align:start position:0% +can just rescale your energy scale uh +whatever you want uh whatever you want + + align:start position:0% +whatever you want uh whatever you want + + + align:start position:0% +whatever you want uh whatever you want +you go to go to find energy EXC and as + + align:start position:0% +you go to go to find energy EXC and as + + + align:start position:0% +you go to go to find energy EXC and as +far as you in the ads + + align:start position:0% +far as you in the ads + + + align:start position:0% +far as you in the ads +5 as far yeah once you decou those + + align:start position:0% +5 as far yeah once you decou those + + + align:start position:0% +5 as far yeah once you decou those +things then you are living in + + align:start position:0% +things then you are living in + + + align:start position:0% +things then you are living in +ads then you are living in the ads and + + align:start position:0% +ads then you are living in the ads and + + + align:start position:0% +ads then you are living in the ads and +then you can talk about the energy scale + + align:start position:0% +then you can talk about the energy scale + + + align:start position:0% +then you can talk about the energy scale +or or any radius as you want just become + + align:start position:0% +or or any radius as you want just become + + + align:start position:0% +or or any radius as you want just become +relative to + + align:start position:0% +relative to + + + align:start position:0% +relative to +itself you see what I mean is that kind + + align:start position:0% +itself you see what I mean is that kind + + + align:start position:0% +itself you see what I mean is that kind +of + + align:start position:0% +of + + + align:start position:0% +of +normalization no no this is not + + align:start position:0% +normalization no no this is not + + + align:start position:0% +normalization no no this is not +normalization this is this is just say + + align:start position:0% +normalization this is this is just say + + + align:start position:0% +normalization this is this is just say +when you normally when we say when we + + align:start position:0% +when you normally when we say when we + + + align:start position:0% +when you normally when we say when we +take the Lage + + align:start position:0% +take the Lage + + + align:start position:0% +take the Lage +limit the reason we take the Lage limit + + align:start position:0% +limit the reason we take the Lage limit + + + align:start position:0% +limit the reason we take the Lage limit +is we want to decou those massive modes + + align:start position:0% +is we want to decou those massive modes + + + align:start position:0% +is we want to decou those massive modes +and once we decover those massive modes + + align:start position:0% +and once we decover those massive modes + + + align:start position:0% +and once we decover those massive modes +and then we consider the finite energy + + align:start position:0% +and then we consider the finite energy + + + align:start position:0% +and then we consider the finite energy +and and when fight energy because we + + align:start position:0% +and and when fight energy because we + + + align:start position:0% +and and when fight energy because we +consider fight energy relative to + + align:start position:0% +consider fight energy relative to + + + align:start position:0% +consider fight energy relative to +L we still consider a fight range of + + align:start position:0% +L we still consider a fight range of + + + align:start position:0% +L we still consider a fight range of +energy it's the same thing as + + align:start position:0% +energy it's the same thing as + + + align:start position:0% +energy it's the same thing as +that is this clear to everybody this is + + align:start position:0% +that is this clear to everybody this is + + + align:start position:0% +that is this clear to everybody this is +a very important + + align:start position:0% +a very important + + + align:start position:0% +a very important +Point + + align:start position:0% +Point + + + align:start position:0% +Point +yeah good + + align:start position:0% +yeah good + + + align:start position:0% +yeah good +yeah the + + align:start position:0% +yeah the + + + align:start position:0% +yeah the +question is that previously in order to + + align:start position:0% +question is that previously in order to + + + align:start position:0% +question is that previously in order to +decouple those high energy modes when we + + align:start position:0% +decouple those high energy modes when we + + + align:start position:0% +decouple those high energy modes when we +take a lower limit we have to take I + + align:start position:0% +take a lower limit we have to take I + + + align:start position:0% +take a lower limit we have to take I +equal to zero so why here we worri about + + align:start position:0% +equal to zero so why here we worri about + + + align:start position:0% +equal to zero so why here we worri about +I go to Infinity IAL Infinity here okay + + align:start position:0% +I go to Infinity IAL Infinity here okay + + + align:start position:0% +I go to Infinity IAL Infinity here okay +why are we worry about IAL Infinity + + align:start position:0% +why are we worry about IAL Infinity + + + align:start position:0% +why are we worry about IAL Infinity +seems like this is uh going outside our + + align:start position:0% +seems like this is uh going outside our + + + align:start position:0% +seems like this is uh going outside our +previous regime uh uh but the answer is + + align:start position:0% +previous regime uh uh but the answer is + + + align:start position:0% +previous regime uh uh but the answer is +that once we decouple those uh high + + align:start position:0% +that once we decouple those uh high + + + align:start position:0% +that once we decouple those uh high +energy mode then you can just extend the + + align:start position:0% +energy mode then you can just extend the + + + align:start position:0% +energy mode then you can just extend the +energy whatever to to whatever energy + + align:start position:0% +energy whatever to to whatever energy + + + align:start position:0% +energy whatever to to whatever energy +range you want because you you have + + align:start position:0% +range you want because you you have + + + align:start position:0% +range you want because you you have +served the purpose of discover decou + + align:start position:0% +served the purpose of discover decou + + + align:start position:0% +served the purpose of discover decou +those uh uh yeah because those thing + + align:start position:0% +those uh uh yeah because those thing + + + align:start position:0% +those uh uh yeah because those thing +already go went to Infinity don't have + + align:start position:0% +already go went to Infinity don't have + + + align:start position:0% +already go went to Infinity don't have +to worry about + + align:start position:0% +to worry about + + + align:start position:0% +to worry about +them yeah is it clear yeah just like in + + align:start position:0% +them yeah is it clear yeah just like in + + + align:start position:0% +them yeah is it clear yeah just like in +the Y Theory we say we take the eny to + + align:start position:0% +the Y Theory we say we take the eny to + + + align:start position:0% +the Y Theory we say we take the eny to +to cover those massive modes but + + align:start position:0% +to cover those massive modes but + + + align:start position:0% +to cover those massive modes but +eventually in the yam we will consider + + align:start position:0% +eventually in the yam we will consider + + + align:start position:0% +eventually in the yam we will consider +very high energy process in the yam + + align:start position:0% +very high energy process in the yam + + + align:start position:0% +very high energy process in the yam +the okay and but but those since we + + align:start position:0% +the okay and but but those since we + + + align:start position:0% +the okay and but but those since we +cover have even even higher energy scale + + align:start position:0% + + + + align:start position:0% + +okay good good + + align:start position:0% +okay good good + + + align:start position:0% +okay good good +good so we call this is so this is one + + align:start position:0% +good so we call this is so this is one + + + align:start position:0% +good so we call this is so this is one +this is + + align:start position:0% +this is + + + align:start position:0% +this is +two so in fact actually one and two they + + align:start position:0% +two so in fact actually one and two they + + + align:start position:0% +two so in fact actually one and two they +are + + align:start position:0% +are + + + align:start position:0% +are +not covering the full anti- de space + + align:start position:0% +not covering the full anti- de space + + + align:start position:0% +not covering the full anti- de space +time so actually they only cover a part + + align:start position:0% +time so actually they only cover a part + + + align:start position:0% +time so actually they only cover a part +of an deal space time so so they they + + align:start position:0% +of an deal space time so so they they + + + align:start position:0% +of an deal space time so so they they +only cover say what is so-call a p a + + align:start position:0% +only cover say what is so-call a p a + + + align:start position:0% +only cover say what is so-call a p a +patch a patch of deed space time anti + + align:start position:0% +patch a patch of deed space time anti + + + align:start position:0% +patch a patch of deed space time anti +deed space time so now let me just + + align:start position:0% +deed space time so now let me just + + + align:start position:0% +deed space time so now let me just +mention a little bit what is normally + + align:start position:0% +mention a little bit what is normally + + + align:start position:0% +mention a little bit what is normally +called the global ads okay so so the ads + + align:start position:0% +called the global ads okay so so the ads + + + align:start position:0% +called the global ads okay so so the ads +or or Global + + align:start position:0% + + + + align:start position:0% + +ads so yeah so let me first write down + + align:start position:0% +ads so yeah so let me first write down + + + align:start position:0% +ads so yeah so let me first write down +the sentence so one + + align:start position:0% + + + + align:start position:0% + +two one + + align:start position:0% +two one + + + align:start position:0% +two one +two + + align:start position:0% + + + + align:start position:0% + +only cover + + align:start position:0% +only cover + + + align:start position:0% +only cover +a + + align:start position:0% + + + + align:start position:0% + +part of four + + align:start position:0% + + + + align:start position:0% + +yes + + align:start position:0% +yes + + + align:start position:0% +yes +okay so the the global ads the so-called + + align:start position:0% +okay so the the global ads the so-called + + + align:start position:0% +okay so the the global ads the so-called +Global + + align:start position:0% + + + + align:start position:0% + +ads can be + + align:start position:0% + + + + align:start position:0% + +defined can be + + align:start position:0% +defined can be + + + align:start position:0% +defined can be +described + + align:start position:0% + + + + align:start position:0% + +as a A hyperboloid in the lent space + + align:start position:0% +as a A hyperboloid in the lent space + + + align:start position:0% +as a A hyperboloid in the lent space +time + + align:start position:0% +time + + + align:start position:0% +time +okay + + align:start position:0% + + + + align:start position:0% + +holoid in + + align:start position:0% + + + + align:start position:0% + +minkovski D plus two minkovski spe time + + align:start position:0% +minkovski D plus two minkovski spe time + + + align:start position:0% +minkovski D plus two minkovski spe time +of + + align:start position:0% + + + + align:start position:0% + +Signature 2 comma D okay so to make this + + align:start position:0% + + + + align:start position:0% + +precise say for example if you go to the + + align:start position:0% +precise say for example if you go to the + + + align:start position:0% +precise say for example if you go to the +gr book for example the cing Hat the + + align:start position:0% +gr book for example the cing Hat the + + + align:start position:0% +gr book for example the cing Hat the +book by Hawking and alies called the + + align:start position:0% +book by Hawking and alies called the + + + align:start position:0% +book by Hawking and alies called the +large scale SP large scale structure of + + align:start position:0% +large scale SP large scale structure of + + + align:start position:0% +large scale SP large scale structure of +space time the way they Define the the + + align:start position:0% +space time the way they Define the the + + + align:start position:0% +space time the way they Define the the +anti deaser is as + + align:start position:0% +anti deaser is as + + + align:start position:0% +anti deaser is as +follows so you + + align:start position:0% +follows so you + + + align:start position:0% +follows so you +consider a d plus 2 Dimension movi space + + align:start position:0% +consider a d plus 2 Dimension movi space + + + align:start position:0% +consider a d plus 2 Dimension movi space +time with Signature 2 comma d + + align:start position:0% +time with Signature 2 comma d + + + align:start position:0% +time with Signature 2 comma d +so you + + align:start position:0% +so you + + + align:start position:0% +so you +consider om minkovski space time like + + align:start position:0% + + + + align:start position:0% + +this okay so now you uh uh uh you have D + + align:start position:0% +this okay so now you uh uh uh you have D + + + align:start position:0% +this okay so now you uh uh uh you have D +positive + + align:start position:0% +positive + + + align:start position:0% +positive +signature and the two negative signature + + align:start position:0% +signature and the two negative signature + + + align:start position:0% +signature and the two negative signature +so X start from minus one index zero + + align:start position:0% +so X start from minus one index zero + + + align:start position:0% +so X start from minus one index zero +which give you the lative uh signature + + align:start position:0% +which give you the lative uh signature + + + align:start position:0% +which give you the lative uh signature +and then you have yeah so this is the + + align:start position:0% +and then you have yeah so this is the + + + align:start position:0% +and then you have yeah so this is the +minkovski space time of the 2 comma D + + align:start position:0% +minkovski space time of the 2 comma D + + + align:start position:0% +minkovski space time of the 2 comma D +signature so now you consider the + + align:start position:0% +signature so now you consider the + + + align:start position:0% +signature so now you consider the +following hypersurface in that space + + align:start position:0% + + + + align:start position:0% + +time + + align:start position:0% +time + + + align:start position:0% +time +okay so this is + + align:start position:0% +okay so this is + + + align:start position:0% +okay so this is +hypoid in that space time and this this + + align:start position:0% +hypoid in that space time and this this + + + align:start position:0% +hypoid in that space time and this this +defines your ads okay so this + + align:start position:0% +defines your ads okay so this + + + align:start position:0% +defines your ads okay so this +surface defines + + align:start position:0% + + + + align:start position:0% + +ads this is + + align:start position:0% +ads this is + + + align:start position:0% +ads this is +Def + + align:start position:0% + + + + align:start position:0% + +ads so of course this is a very + + align:start position:0% +ads so of course this is a very + + + align:start position:0% +ads so of course this is a very +different way to parameterize uh uh to + + align:start position:0% +different way to parameterize uh uh to + + + align:start position:0% +different way to parameterize uh uh to +uh to um parameterize a this then either + + align:start position:0% +uh to um parameterize a this then either + + + align:start position:0% +uh to um parameterize a this then either +this Matrix or that + + align:start position:0% +this Matrix or that + + + align:start position:0% +this Matrix or that +Matrix and you can actually pariz ads in + + align:start position:0% +Matrix and you can actually pariz ads in + + + align:start position:0% +Matrix and you can actually pariz ads in +many many different ways so now let me + + align:start position:0% +many many different ways so now let me + + + align:start position:0% +many many different ways so now let me +just mention a few ways to a few choice + + align:start position:0% +just mention a few ways to a few choice + + + align:start position:0% +just mention a few ways to a few choice +of different coordinates to parameterize + + align:start position:0% +of different coordinates to parameterize + + + align:start position:0% +of different coordinates to parameterize +this hyperboloids + + align:start position:0% + + + + align:start position:0% + +okay so the first is what we one is + + align:start position:0% +okay so the first is what we one is + + + align:start position:0% +okay so the first is what we one is +called the P coordinates is this + + align:start position:0% + + + + align:start position:0% + +one so first we want we call pcre + + align:start position:0% +one so first we want we call pcre + + + align:start position:0% +one so first we want we call pcre +coordinates so in this P coordinates you + + align:start position:0% +coordinates so in this P coordinates you + + + align:start position:0% +coordinates so in this P coordinates you +introduce r r there is given by x - + + align:start position:0% +introduce r r there is given by x - + + + align:start position:0% +introduce r r there is given by x - +one plus + + align:start position:0% +one plus + + + align:start position:0% +one plus +XD so you take the one of the netive + + align:start position:0% +XD so you take the one of the netive + + + align:start position:0% +XD so you take the one of the netive +signature and the one of the positive + + align:start position:0% +signature and the one of the positive + + + align:start position:0% +signature and the one of the positive +signature you take xus One X add them + + align:start position:0% +signature you take xus One X add them + + + align:start position:0% +signature you take xus One X add them +together so this is like some kind of + + align:start position:0% +together so this is like some kind of + + + align:start position:0% +together so this is like some kind of +nightc and uh and then you write X + + align:start position:0% +nightc and uh and then you write X + + + align:start position:0% +nightc and uh and then you write X +mu so there we always always write X + + align:start position:0% +mu so there we always always write X + + + align:start position:0% +mu so there we always always write X +mu equal to + + align:start position:0% +mu equal to + + + align:start position:0% +mu equal to +TX okay so this is a d dimensional movi + + align:start position:0% +TX okay so this is a d dimensional movi + + + align:start position:0% +TX okay so this is a d dimensional movi +coordinates add X mu equal to R * + + align:start position:0% +coordinates add X mu equal to R * + + + align:start position:0% +coordinates add X mu equal to R * +Capital + + align:start position:0% +Capital + + + align:start position:0% +Capital +mu / by + + align:start position:0% +mu / by + + + align:start position:0% +mu / by +R + + align:start position:0% +R + + + align:start position:0% +R +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +um in this + + align:start position:0% +um in this + + + align:start position:0% +um in this +hyperboloid you make this St + + align:start position:0% + + + + align:start position:0% + +and then you restrict to the region of R + + align:start position:0% +and then you restrict to the region of R + + + align:start position:0% +and then you restrict to the region of R +greater than + + align:start position:0% + + + + align:start position:0% + +zero then you recover so + + align:start position:0% +zero then you recover so + + + align:start position:0% +zero then you recover so +one correspond + + align:start position:0% + + + + align:start position:0% + +to are greater than zero part of this + + align:start position:0% +to are greater than zero part of this + + + align:start position:0% +to are greater than zero part of this +magic + + align:start position:0% +magic + + + align:start position:0% +magic +okay of this space time and you can + + align:start position:0% +okay of this space time and you can + + + align:start position:0% +okay of this space time and you can +easily check yourself just make this + + align:start position:0% +easily check yourself just make this + + + align:start position:0% +easily check yourself just make this +definition uh this is exercise you + + align:start position:0% +definition uh this is exercise you + + + align:start position:0% +definition uh this is exercise you +should do which I don't have time to do + + align:start position:0% +should do which I don't have time to do + + + align:start position:0% +should do which I don't have time to do +here just plug this in plug this into + + align:start position:0% +here just plug this in plug this into + + + align:start position:0% +here just plug this in plug this into +that Matrix plug this parameterization + + align:start position:0% +that Matrix plug this parameterization + + + align:start position:0% +that Matrix plug this parameterization +into that Matrix and then you find you + + align:start position:0% +into that Matrix and then you find you + + + align:start position:0% +into that Matrix and then you find you +will recover one and one will + + align:start position:0% +will recover one and one will + + + align:start position:0% +will recover one and one will +corresponding one is only restricted to + + align:start position:0% +corresponding one is only restricted to + + + align:start position:0% +corresponding one is only restricted to +r equal to Z to Infinity so you only + + align:start position:0% +r equal to Z to Infinity so you only + + + align:start position:0% +r equal to Z to Infinity so you only +restrict to R greater than zero part of + + align:start position:0% +restrict to R greater than zero part of + + + align:start position:0% +restrict to R greater than zero part of +this and if you just introduce this in + + align:start position:0% +this and if you just introduce this in + + + align:start position:0% +this and if you just introduce this in +pcle of course R can be smaller than + + align:start position:0% +pcle of course R can be smaller than + + + align:start position:0% +pcle of course R can be smaller than +zero + + align:start position:0% +zero + + + align:start position:0% +zero +okay so so this are P coordinates so + + align:start position:0% +okay so so this are P coordinates so + + + align:start position:0% +okay so so this are P coordinates so +once you go to to that matric then go to + + align:start position:0% +once you go to to that matric then go to + + + align:start position:0% +once you go to to that matric then go to +this matric just it's the + + align:start position:0% +this matric just it's the + + + align:start position:0% +this matric just it's the +same also let me describe something + + align:start position:0% +same also let me describe something + + + align:start position:0% +same also let me describe something +called the global + + align:start position:0% + + + + align:start position:0% + +coordinates so this is BYO is the + + align:start position:0% +coordinates so this is BYO is the + + + align:start position:0% +coordinates so this is BYO is the +following + + align:start position:0% +following + + + align:start position:0% +following +structure so this is have the form of + + align:start position:0% +structure so this is have the form of + + + align:start position:0% +structure so this is have the form of +the + + align:start position:0% +the + + + align:start position:0% +the +two the the difference of two + + align:start position:0% +two the the difference of two + + + align:start position:0% +two the the difference of two +squares so I can write + + align:start position:0% +squares so I can write + + + align:start position:0% +squares so I can write +so + + align:start position:0% +so + + + align:start position:0% +so +let's write + + align:start position:0% +let's write + + + align:start position:0% +let's write +x i to one to d x i s to be some some + + align:start position:0% +x i to one to d x i s to be some some + + + align:start position:0% +x i to one to d x i s to be some some +function R square and R square time R + + align:start position:0% +function R square and R square time R + + + align:start position:0% +function R square and R square time R +square so this R have nothing to do with + + align:start position:0% +square so this R have nothing to do with + + + align:start position:0% +square so this R have nothing to do with +that RW now we are doing a different set + + align:start position:0% +that RW now we are doing a different set + + + align:start position:0% +that RW now we are doing a different set +of coordinates uh I'm just using the the + + align:start position:0% +of coordinates uh I'm just using the the + + + align:start position:0% +of coordinates uh I'm just using the the +same notation for + + align:start position:0% +same notation for + + + align:start position:0% +same notation for +convenience so so so let's introduce a + + align:start position:0% +convenience so so so let's introduce a + + + align:start position:0% +convenience so so so let's introduce a +new coordinate r which is just the sum + + align:start position:0% +new coordinate r which is just the sum + + + align:start position:0% +new coordinate r which is just the sum +of all these + + align:start position:0% +of all these + + + align:start position:0% +of all these +square and then I + + align:start position:0% +square and then I + + + align:start position:0% +square and then I +introduce then then from this equation + + align:start position:0% +introduce then then from this equation + + + align:start position:0% +introduce then then from this equation +the X1 minus x0 s should be equal to r² + + align:start position:0% +the X1 minus x0 s should be equal to r² + + + align:start position:0% +the X1 minus x0 s should be equal to r² ++ 1 * R + + align:start position:0% ++ 1 * R + + + align:start position:0% ++ 1 * R +square + + align:start position:0% + + + + align:start position:0% + +okay so now I can so this is a this is a + + align:start position:0% +okay so now I can so this is a this is a + + + align:start position:0% +okay so now I can so this is a this is a +circle so for fixed R this is a + + align:start position:0% +circle so for fixed R this is a + + + align:start position:0% +circle so for fixed R this is a +circle for fixed R this is a D minus one + + align:start position:0% +circle for fixed R this is a D minus one + + + align:start position:0% +circle for fixed R this is a D minus one +dimensional + + align:start position:0% +dimensional + + + align:start position:0% +dimensional +sphere + + align:start position:0% +sphere + + + align:start position:0% +sphere +okay so I can introduce this D minus one + + align:start position:0% +okay so I can introduce this D minus one + + + align:start position:0% +okay so I can introduce this D minus one +spical coordinates on this and introduce + + align:start position:0% +spical coordinates on this and introduce + + + align:start position:0% +spical coordinates on this and introduce +a circular circular coordinate on this + + align:start position:0% +a circular circular coordinate on this + + + align:start position:0% +a circular circular coordinate on this +okay so if I do that so let me just call + + align:start position:0% +okay so if I do that so let me just call + + + align:start position:0% +okay so if I do that so let me just call +the circular coordinate on here + + align:start position:0% +the circular coordinate on here + + + align:start position:0% +the circular coordinate on here +to uh the polar coordinate in the in the + + align:start position:0% +to uh the polar coordinate in the in the + + + align:start position:0% +to uh the polar coordinate in the in the +in the xus Y uh + + align:start position:0% +in the xus Y uh + + + align:start position:0% +in the xus Y uh +uh + + align:start position:0% +uh + + + align:start position:0% +uh +polar coordinates + + align:start position:0% + + + + align:start position:0% + +in the xus one and x0 plane so let me + + align:start position:0% +in the xus one and x0 plane so let me + + + align:start position:0% +in the xus one and x0 plane so let me +call this tle and let me call the sple + + align:start position:0% +call this tle and let me call the sple + + + align:start position:0% +call this tle and let me call the sple +coordinate here Omega minus one Omega D + + align:start position:0% +coordinate here Omega minus one Omega D + + + align:start position:0% +coordinate here Omega minus one Omega D +minus one okay then you plug this into + + align:start position:0% +minus one okay then you plug this into + + + align:start position:0% +minus one okay then you plug this into +here then you find you find the + + align:start position:0% +here then you find you find the + + + align:start position:0% +here then you find you find the +following + + align:start position:0% + + + + align:start position:0% + +matric + + align:start position:0% + + + + align:start position:0% + +so you find the following + + align:start position:0% +so you find the following + + + align:start position:0% +so you find the following +magic you + + align:start position:0% +magic you + + + align:start position:0% +magic you +find D + + align:start position:0% +find D + + + align:start position:0% +find D +s² equal to + + align:start position:0% + + + + align:start position:0% + +r² minus 1 + r² d + + align:start position:0% + + + + align:start position:0% + +square plus d r² + 1 + + + align:start position:0% +square plus d r² + 1 + + + + align:start position:0% +square plus d r² + 1 + +r² + r sare d Omega D minus 1 + + align:start position:0% +r² + r sare d Omega D minus 1 + + + align:start position:0% +r² + r sare d Omega D minus 1 +s + + align:start position:0% + + + + align:start position:0% + +okay so so remember T is the polar + + align:start position:0% +okay so so remember T is the polar + + + align:start position:0% +okay so so remember T is the polar +coordinate in this xus one and x0 plane + + align:start position:0% +coordinate in this xus one and x0 plane + + + align:start position:0% +coordinate in this xus one and x0 plane +and Omega D minus one is the polar + + align:start position:0% +and Omega D minus one is the polar + + + align:start position:0% +and Omega D minus one is the polar +coordinate in the X1 to + + align:start position:0% +coordinate in the X1 to + + + align:start position:0% +coordinate in the X1 to +XT + + align:start position:0% +XT + + + align:start position:0% +XT +okay and then you get + + align:start position:0% +okay and then you get + + + align:start position:0% +okay and then you get +this again it's an exercise you should + + align:start position:0% +this again it's an exercise you should + + + align:start position:0% +this again it's an exercise you should +go through yourself yes so question so + + align:start position:0% +go through yourself yes so question so + + + align:start position:0% +go through yourself yes so question so +I'm just trying to visualize this so + + align:start position:0% +I'm just trying to visualize this so + + + align:start position:0% +I'm just trying to visualize this so +there's these I mean at least the way + + align:start position:0% +there's these I mean at least the way + + + align:start position:0% +there's these I mean at least the way +works in RM imagine so you have these + + align:start position:0% +works in RM imagine so you have these + + + align:start position:0% +works in RM imagine so you have these +two sheets which are like disjoint from + + align:start position:0% +two sheets which are like disjoint from + + + align:start position:0% +two sheets which are like disjoint from +each other so how is it that this + + align:start position:0% +each other so how is it that this + + + align:start position:0% +each other so how is it that this +enables us to go smoothly between them + + align:start position:0% +enables us to go smoothly between them + + + align:start position:0% +enables us to go smoothly between them +like it seems that there's so maybe I'm + + align:start position:0% +like it seems that there's so maybe I'm + + + align:start position:0% +like it seems that there's so maybe I'm +confused about what you did okay what do + + align:start position:0% +confused about what you did okay what do + + + align:start position:0% +confused about what you did okay what do +you mean so we're trying to describe + + align:start position:0% +you mean so we're trying to describe + + + align:start position:0% +you mean so we're trying to describe +this object which has two disjoint + + align:start position:0% +this object which has two disjoint + + + align:start position:0% +this object which has two disjoint +components we only look at one component + + align:start position:0% +components we only look at one component + + + align:start position:0% +components we only look at one component +so what's the point of global + + align:start position:0% +so what's the point of global + + + align:start position:0% +so what's the point of global +coordinates is it just a + + align:start position:0% +coordinates is it just a + + + align:start position:0% +coordinates is it just a +different no no no no that only covers + + align:start position:0% +different no no no no that only covers + + + align:start position:0% +different no no no no that only covers +part of the one + + align:start position:0% + + + + align:start position:0% + +component oh I see okay + + align:start position:0% + + + + align:start position:0% + +yes okay yeah okay good so you look at + + align:start position:0% +yes okay yeah okay good so you look at + + + align:start position:0% +yes okay yeah okay good so you look at +here um yeah so uh so so that's the M + + align:start position:0% +here um yeah so uh so so that's the M + + + align:start position:0% +here um yeah so uh so so that's the M +again R where goes from zero to Infinity + + align:start position:0% +again R where goes from zero to Infinity + + + align:start position:0% +again R where goes from zero to Infinity +but this R is very different from this R + + align:start position:0% +but this R is very different from this R + + + align:start position:0% +but this R is very different from this R +law + + align:start position:0% +law + + + align:start position:0% +law +okay uh so in this + + align:start position:0% +okay uh so in this + + + align:start position:0% +okay uh so in this +definition t is a polar coordinate so in + + align:start position:0% +definition t is a polar coordinate so in + + + align:start position:0% +definition t is a polar coordinate so in +this definition t will go from 0 to 2 pi + + align:start position:0% +this definition t will go from 0 to 2 pi + + + align:start position:0% +this definition t will go from 0 to 2 pi +okay but once you write it in this + + align:start position:0% +okay but once you write it in this + + + align:start position:0% +okay but once you write it in this +form nothing depends on T so you can + + align:start position:0% +form nothing depends on T so you can + + + align:start position:0% +form nothing depends on T so you can +extend T to any range you want so once + + align:start position:0% +extend T to any range you want so once + + + align:start position:0% +extend T to any range you want so once +we write this form we take + + align:start position:0% +we write this form we take + + + align:start position:0% +we write this form we take +to goes to minus infinity to plus + + align:start position:0% +to goes to minus infinity to plus + + + align:start position:0% +to goes to minus infinity to plus +infinity so this is our gening time + + align:start position:0% +infinity so this is our gening time + + + align:start position:0% +infinity so this is our gening time +rather than from 0 to from PI 0 to 0 to + + align:start position:0% +rather than from 0 to from PI 0 to 0 to + + + align:start position:0% +rather than from 0 to from PI 0 to 0 to +2 pi we take to from minus infinity to + + align:start position:0% +2 pi we take to from minus infinity to + + + align:start position:0% +2 pi we take to from minus infinity to +plus infinity so sometimes this is also + + align:start position:0% +plus infinity so sometimes this is also + + + align:start position:0% +plus infinity so sometimes this is also +called extended + + align:start position:0% +called extended + + + align:start position:0% +called extended +ads sometime people don't just bother to + + align:start position:0% +ads sometime people don't just bother to + + + align:start position:0% +ads sometime people don't just bother to +do that you just extend it automatically + + align:start position:0% +do that you just extend it automatically + + + align:start position:0% +do that you just extend it automatically +okay so strictly + + align:start position:0% +okay so strictly + + + align:start position:0% +okay so strictly +speaking + + align:start position:0% +speaking + + + align:start position:0% +speaking +this as a definition of ads only + + align:start position:0% +this as a definition of ads only + + + align:start position:0% +this as a definition of ads only +corresponding to the part of to from 0 + + align:start position:0% +corresponding to the part of to from 0 + + + align:start position:0% +corresponding to the part of to from 0 +to 2 pi okay and and when you when you + + align:start position:0% +to 2 pi okay and and when you when you + + + align:start position:0% +to 2 pi okay and and when you when you +extend to from minus infinity to minus + + align:start position:0% +extend to from minus infinity to minus + + + align:start position:0% +extend to from minus infinity to minus +infinity you actually have infinite copy + + align:start position:0% +infinity you actually have infinite copy + + + align:start position:0% +infinity you actually have infinite copy +of + + align:start position:0% + + + + align:start position:0% + +this okay so now with one more thing we + + align:start position:0% +this okay so now with one more thing we + + + align:start position:0% +this okay so now with one more thing we +can so this coordinate is + + align:start position:0% +can so this coordinate is + + + align:start position:0% +can so this coordinate is +nice now it covers + + align:start position:0% +nice now it covers + + + align:start position:0% +nice now it covers +everything covers everything but even + + align:start position:0% +everything covers everything but even + + + align:start position:0% +everything covers everything but even +actually a little bit more because you + + align:start position:0% +actually a little bit more because you + + + align:start position:0% +actually a little bit more because you +have now you extend the tower to minus + + align:start position:0% +have now you extend the tower to minus + + + align:start position:0% +have now you extend the tower to minus +infinity + + align:start position:0% +infinity + + + align:start position:0% +infinity +infinity we can visualize this matric a + + align:start position:0% +infinity we can visualize this matric a + + + align:start position:0% +infinity we can visualize this matric a +little bit better by doing the the + + align:start position:0% +little bit better by doing the the + + + align:start position:0% +little bit better by doing the the +following a lot of transformation so now + + align:start position:0% +following a lot of transformation so now + + + align:start position:0% +following a lot of transformation so now +let's + + align:start position:0% +let's + + + align:start position:0% +let's +take yeah before so that let me say a + + align:start position:0% +take yeah before so that let me say a + + + align:start position:0% +take yeah before so that let me say a +few words about yeah let me just uh uh + + align:start position:0% +few words about yeah let me just uh uh + + + align:start position:0% +few words about yeah let me just uh uh +do this first let's take to again take + + align:start position:0% +do this first let's take to again take + + + align:start position:0% +do this first let's take to again take +Ral to tangent row row some other + + align:start position:0% +Ral to tangent row row some other + + + align:start position:0% +Ral to tangent row row some other +coordinates and R from Z to Infinity + + align:start position:0% +coordinates and R from Z to Infinity + + + align:start position:0% +coordinates and R from Z to Infinity +then row will be from0 to 2 Pi Pi / + + align:start position:0% +then row will be from0 to 2 Pi Pi / + + + align:start position:0% +then row will be from0 to 2 Pi Pi / + + align:start position:0% + + + align:start position:0% +okay Z pi + + align:start position:0% +okay Z pi + + + align:start position:0% +okay Z pi +two and you plug this into + + align:start position:0% + + + + align:start position:0% + +here is a little bit + + align:start position:0% +here is a little bit + + + align:start position:0% +here is a little bit +tiny so after 2 seconds you find the + + align:start position:0% +tiny so after 2 seconds you find the + + + align:start position:0% +tiny so after 2 seconds you find the +following + + align:start position:0% + + + + align:start position:0% + +matric + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +so this is easy to see because 1 plus T + + align:start position:0% +so this is easy to see because 1 plus T + + + align:start position:0% +so this is easy to see because 1 plus T +row square is just one over cosine + + align:start position:0% +row square is just one over cosine + + + align:start position:0% +row square is just one over cosine +square + + align:start position:0% +square + + + align:start position:0% +square +and ex true so the reason this matric is + + align:start position:0% +and ex true so the reason this matric is + + + align:start position:0% +and ex true so the reason this matric is +nice because other than this conformal + + align:start position:0% +nice because other than this conformal + + + align:start position:0% +nice because other than this conformal +Factor this thing we can easily + + align:start position:0% +Factor this thing we can easily + + + align:start position:0% +Factor this thing we can easily +recognize so this is just a + + align:start position:0% +recognize so this is just a + + + align:start position:0% +recognize so this is just a +cylinder so this is just a + + align:start position:0% +cylinder so this is just a + + + align:start position:0% +cylinder so this is just a +cylinder and let me draw it here + + align:start position:0% + + + + align:start position:0% + +so this is a + + align:start position:0% + + + + align:start position:0% + +cylinder + + align:start position:0% +cylinder + + + align:start position:0% +cylinder +okay so this direction can be consider + + align:start position:0% +okay so this direction can be consider + + + align:start position:0% +okay so this direction can be consider +the the radial + + align:start position:0% + + + + align:start position:0% + +direction is the row Direction + + align:start position:0% +direction is the row Direction + + + align:start position:0% +direction is the row Direction +Direction and the circular dire and this + + align:start position:0% +Direction and the circular dire and this + + + align:start position:0% +Direction and the circular dire and this +direction is the T + + align:start position:0% + + + + align:start position:0% + +Direction and this direction is the uh + + align:start position:0% +Direction and this direction is the uh + + + align:start position:0% +Direction and this direction is the uh +the the Omega D minus one or or the + + align:start position:0% +the the Omega D minus one or or the + + + align:start position:0% +the the Omega D minus one or or the +polar coordinate Direction I'm only + + align:start position:0% +polar coordinate Direction I'm only + + + align:start position:0% +polar coordinate Direction I'm only +drawing one of + + align:start position:0% +drawing one of + + + align:start position:0% +drawing one of +them + + align:start position:0% +them + + + align:start position:0% +them +okay so essentially this have a + + align:start position:0% +okay so essentially this have a + + + align:start position:0% +okay so essentially this have a +structure of a + + align:start position:0% +structure of a + + + align:start position:0% +structure of a +cylinder and at the center here I have + + align:start position:0% +cylinder and at the center here I have + + + align:start position:0% +cylinder and at the center here I have +row equal to zero + + align:start position:0% +row equal to zero + + + align:start position:0% +row equal to zero +and here I have row equal to pi/ + + align:start position:0% +and here I have row equal to pi/ + + + align:start position:0% +and here I have row equal to pi/ +2 okay Row from 0 to pi/ + + align:start position:0% +2 okay Row from 0 to pi/ + + + align:start position:0% +2 okay Row from 0 to pi/ +2 okay and uh and when you go to pi/ two + + align:start position:0% +2 okay and uh and when you go to pi/ two + + + align:start position:0% +2 okay and uh and when you go to pi/ two +this Quant Factor goes zero so so the + + align:start position:0% +this Quant Factor goes zero so so the + + + align:start position:0% +this Quant Factor goes zero so so the +overall scale blows up so so here is + + align:start position:0% +overall scale blows up so so here is + + + align:start position:0% +overall scale blows up so so here is +your + + align:start position:0% +your + + + align:start position:0% +your +boundary so so the uh um so pi over + + align:start position:0% +boundary so so the uh um so pi over + + + align:start position:0% +boundary so so the uh um so pi over +two yeah so so + + align:start position:0% +two yeah so so + + + align:start position:0% +two yeah so so +the so pi/ two is the boundary + + align:start position:0% + + + + align:start position:0% + +okay is this + + align:start position:0% +okay is this + + + align:start position:0% +okay is this +clear the pi/ two is the boundary now + + align:start position:0% +clear the pi/ two is the boundary now + + + align:start position:0% +clear the pi/ two is the boundary now +the boundary map so so so the boundary + + align:start position:0% +the boundary map so so so the boundary + + + align:start position:0% +the boundary map so so so the boundary +of the + + align:start position:0% +of the + + + align:start position:0% +of the +cylinder so the + + align:start position:0% + + + + align:start position:0% + +boundary now is at sitting atal to pi/ + + align:start position:0% + + + + align:start position:0% + +2 has the + + align:start position:0% +2 has the + + + align:start position:0% +2 has the +topology of r + + align:start position:0% +topology of r + + + align:start position:0% +topology of r +time sdus + + align:start position:0% +time sdus + + + align:start position:0% +time sdus +one okay so the boundary itself is a so + + align:start position:0% +one okay so the boundary itself is a so + + + align:start position:0% +one okay so the boundary itself is a so +the boundary itself is the cinder the + + align:start position:0% +the boundary itself is the cinder the + + + align:start position:0% +the boundary itself is the cinder the +whole Space is is a solid cylinder it's + + align:start position:0% +whole Space is is a solid cylinder it's + + + align:start position:0% +whole Space is is a solid cylinder it's +a fied cylinder + + align:start position:0% +a fied cylinder + + + align:start position:0% +a fied cylinder +okay and but the scale factor blows up + + align:start position:0% +okay and but the scale factor blows up + + + align:start position:0% +okay and but the scale factor blows up +when you approach the boundary because + + align:start position:0% +when you approach the boundary because + + + align:start position:0% +when you approach the boundary because +of this pre + + align:start position:0% + + + + align:start position:0% + +factor and the r is the time and the + + align:start position:0% +factor and the r is the time and the + + + align:start position:0% +factor and the r is the time and the +sdus one is + + align:start position:0% +sdus one is + + + align:start position:0% +sdus one is +the so so let's now to visualize this + + align:start position:0% +the so so let's now to visualize this + + + align:start position:0% +the so so let's now to visualize this +space a little bit more better let's + + align:start position:0% +space a little bit more better let's + + + align:start position:0% +space a little bit more better let's +look at the + + align:start position:0% +look at the + + + align:start position:0% +look at the +cross-section so imagine you put a + + align:start position:0% +cross-section so imagine you put a + + + align:start position:0% +cross-section so imagine you put a +plane in this space okay so now imagine + + align:start position:0% +plane in this space okay so now imagine + + + align:start position:0% +plane in this space okay so now imagine +and now let me call this U this circular + + align:start position:0% +and now let me call this U this circular + + + align:start position:0% +and now let me call this U this circular +Direction let's call it Theta and then + + align:start position:0% +Direction let's call it Theta and then + + + align:start position:0% +Direction let's call it Theta and then +now let's consider the cross-section + + align:start position:0% +now let's consider the cross-section + + + align:start position:0% +now let's consider the cross-section +across this solid cylinder so then we + + align:start position:0% +across this solid cylinder so then we + + + align:start position:0% +across this solid cylinder so then we +just have a + + align:start position:0% + + + + align:start position:0% + +plane okay have a plane I should not + + align:start position:0% +plane okay have a plane I should not + + + align:start position:0% +plane okay have a plane I should not +have + + align:start position:0% + + + + align:start position:0% + +let's consider this cross-section okay + + align:start position:0% +let's consider this cross-section okay + + + align:start position:0% +let's consider this cross-section okay +uh in the center of this + + align:start position:0% +uh in the center of this + + + align:start position:0% +uh in the center of this +cylinder I cut half cylinder cut it in + + align:start position:0% +cylinder I cut half cylinder cut it in + + + align:start position:0% +cylinder I cut half cylinder cut it in +half so so um so for example in this + + align:start position:0% +half so so um so for example in this + + + align:start position:0% +half so so um so for example in this +notation so this will be row equal to + + align:start position:0% +notation so this will be row equal to + + + align:start position:0% +notation so this will be row equal to +Zer so here is rowal to Pi / + + align:start position:0% +Zer so here is rowal to Pi / + + + align:start position:0% +Zer so here is rowal to Pi / +2 and I introduce this angular + + align:start position:0% +2 and I introduce this angular + + + align:start position:0% +2 and I introduce this angular +coordinate that corresponding to Theta + + align:start position:0% +coordinate that corresponding to Theta + + + align:start position:0% +coordinate that corresponding to Theta +equal to zero and here will be again row + + align:start position:0% +equal to zero and here will be again row + + + align:start position:0% +equal to zero and here will be again row += to Pi / 2 but Theta equal to + + align:start position:0% += to Pi / 2 but Theta equal to + + + align:start position:0% += to Pi / 2 but Theta equal to +Pi + + align:start position:0% + + + + align:start position:0% + +okay and again this is the TP + + align:start position:0% + + + + align:start position:0% + +direction is they clear what I'm doing I + + align:start position:0% +direction is they clear what I'm doing I + + + align:start position:0% +direction is they clear what I'm doing I +cut s in half and that's that + + align:start position:0% + + + + align:start position:0% + +cross-section + + align:start position:0% +cross-section + + + align:start position:0% +cross-section +so now because of this T because of + + align:start position:0% +so now because of this T because of + + + align:start position:0% +so now because of this T because of +this structure of this times or + + align:start position:0% +this structure of this times or + + + align:start position:0% +this structure of this times or +conformal factor of all scale + + align:start position:0% +conformal factor of all scale + + + align:start position:0% +conformal factor of all scale +factor so the propagation of a light + + align:start position:0% +factor so the propagation of a light + + + align:start position:0% +factor so the propagation of a light +Ray does not depend on this overall + + align:start position:0% +Ray does not depend on this overall + + + align:start position:0% +Ray does not depend on this overall +Factor the propagation of that Ray can + + align:start position:0% +Factor the propagation of that Ray can + + + align:start position:0% +Factor the propagation of that Ray can +be seen from here okay so now let's + + align:start position:0% +be seen from here okay so now let's + + + align:start position:0% +be seen from here okay so now let's +consider the radial that Ray which only + + align:start position:0% +consider the radial that Ray which only + + + align:start position:0% +consider the radial that Ray which only +goes into the row Direction say so + + align:start position:0% +goes into the row Direction say so + + + align:start position:0% +goes into the row Direction say so +there's no in the in this angle + + align:start position:0% +there's no in the in this angle + + + align:start position:0% +there's no in the in this angle +Direction Let's can the radial light + + align:start position:0% +Direction Let's can the radial light + + + align:start position:0% +Direction Let's can the radial light +Ray then then from that picture it's + + align:start position:0% +Ray then then from that picture it's + + + align:start position:0% +Ray then then from that picture it's +very clear so let's say this is to equal + + align:start position:0% +very clear so let's say this is to equal + + + align:start position:0% +very clear so let's say this is to equal +to + + align:start position:0% + + + + align:start position:0% + +zero then actually takes only Pi / + + align:start position:0% +zero then actually takes only Pi / + + + align:start position:0% +zero then actually takes only Pi / +2 for light rate to reach the + + align:start position:0% + + + + align:start position:0% + +boundary okay because the row only goes + + align:start position:0% +boundary okay because the row only goes + + + align:start position:0% +boundary okay because the row only goes +from PI pi/ two and that rate only TR + + align:start position:0% +from PI pi/ two and that rate only TR + + + align:start position:0% +from PI pi/ two and that rate only TR +always traveling 45° so this is just + + align:start position:0% +always traveling 45° so this is just + + + align:start position:0% +always traveling 45° so this is just +like if you look at the to Plus Square + + align:start position:0% +like if you look at the to Plus Square + + + align:start position:0% +like if you look at the to Plus Square +this just + + align:start position:0% +this just + + + align:start position:0% +this just +minkovski and so lat travel + + align:start position:0% + + + + align:start position:0% + +45° and and then you reach the boundary + + align:start position:0% +45° and and then you reach the boundary + + + align:start position:0% +45° and and then you reach the boundary +and then take lot pi over two yeah so + + align:start position:0% +and then take lot pi over two yeah so + + + align:start position:0% +and then take lot pi over two yeah so +this is pi/ two so this is toal to zero + + align:start position:0% +this is pi/ two so this is toal to zero + + + align:start position:0% +this is pi/ two so this is toal to zero +and then this then this will be tall + + align:start position:0% +and then this then this will be tall + + + align:start position:0% +and then this then this will be tall +equal + + align:start position:0% + + + + align:start position:0% + +to pi/ + + align:start position:0% +to pi/ + + + align:start position:0% +to pi/ +2 then then suppose you put some + + align:start position:0% +2 then then suppose you put some + + + align:start position:0% +2 then then suppose you put some +reflecting wall here + + align:start position:0% + + + + align:start position:0% + +then by the time tal to + + align:start position:0% + + + + align:start position:0% + +Pi it it has bounced + + align:start position:0% +Pi it it has bounced + + + align:start position:0% +Pi it it has bounced +back + + align:start position:0% +back + + + align:start position:0% +back +okay and now if you go lot around then + + align:start position:0% +okay and now if you go lot around then + + + align:start position:0% +okay and now if you go lot around then +after that toal 2 pi then precisely go + + align:start position:0% +after that toal 2 pi then precisely go + + + align:start position:0% +after that toal 2 pi then precisely go +back to the + + align:start position:0% +back to the + + + align:start position:0% +back to the +origin then you go through a period okay + + align:start position:0% +origin then you go through a period okay + + + align:start position:0% +origin then you go through a period okay +and that actually precisely is that tal + + align:start position:0% +and that actually precisely is that tal + + + align:start position:0% +and that actually precisely is that tal +to 2 pi which you define the angular + + align:start position:0% +to 2 pi which you define the angular + + + align:start position:0% +to 2 pi which you define the angular +coordinates yeah if you follow follow + + align:start position:0% +coordinates yeah if you follow follow + + + align:start position:0% +coordinates yeah if you follow follow +that if you follow that then that + + align:start position:0% +that if you follow that then that + + + align:start position:0% +that if you follow that then that +corresponding to precisely one period of + + align:start position:0% +corresponding to precisely one period of + + + align:start position:0% +corresponding to precisely one period of +the light rate traveling in this okay + + align:start position:0% +the light rate traveling in this okay + + + align:start position:0% +the light rate traveling in this okay +but but the key thing is that the light + + align:start position:0% +but but the key thing is that the light + + + align:start position:0% +but but the key thing is that the light +rate will travel pi/ two to the + + align:start position:0% +rate will travel pi/ two to the + + + align:start position:0% +rate will travel pi/ two to the +boundary and now you can check if you + + align:start position:0% +boundary and now you can check if you + + + align:start position:0% +boundary and now you can check if you +look at + + align:start position:0% +look at + + + align:start position:0% +look at +the not the light Ray so light Ray + + align:start position:0% +the not the light Ray so light Ray + + + align:start position:0% +the not the light Ray so light Ray +travels along the light nastics but if + + align:start position:0% +travels along the light nastics but if + + + align:start position:0% +travels along the light nastics but if +you look at the time neasc which is + + align:start position:0% +you look at the time neasc which is + + + align:start position:0% +you look at the time neasc which is +traveled by by Massive particle then you + + align:start position:0% +traveled by by Massive particle then you + + + align:start position:0% +traveled by by Massive particle then you +can show that the massive particle level + + align:start position:0% +can show that the massive particle level + + + align:start position:0% +can show that the massive particle level +reach the boundary it will go into a + + align:start position:0% +reach the boundary it will go into a + + + align:start position:0% +reach the boundary it will go into a +motion like + + align:start position:0% +motion like + + + align:start position:0% +motion like +this okay so this is a massive + + align:start position:0% + + + + align:start position:0% + +particle uh so the massive particle will + + align:start position:0% +particle uh so the massive particle will + + + align:start position:0% +particle uh so the massive particle will +never reach the boundary we always uh be + + align:start position:0% +never reach the boundary we always uh be + + + align:start position:0% +never reach the boundary we always uh be +reflected + + align:start position:0% +reflected + + + align:start position:0% +reflected +back uh uh intuitively from the gravity + + align:start position:0% +back uh uh intuitively from the gravity + + + align:start position:0% +back uh uh intuitively from the gravity +potential okay so you will show this + + align:start position:0% +potential okay so you will show this + + + align:start position:0% +potential okay so you will show this +fact yourself in your pet to show that + + align:start position:0% +fact yourself in your pet to show that + + + align:start position:0% +fact yourself in your pet to show that +actually the massive particle will never + + align:start position:0% +actually the massive particle will never + + + align:start position:0% +actually the massive particle will never +reach the + + align:start position:0% +reach the + + + align:start position:0% +reach the +boundary so in the + + align:start position:0% + + + + align:start position:0% + +sense in the + + align:start position:0% + + + + align:start position:0% + +sense so if you look at this Matrix at + + align:start position:0% +sense so if you look at this Matrix at + + + align:start position:0% +sense so if you look at this Matrix at +row equal to + + align:start position:0% + + + + align:start position:0% + +zero at row to Z this is essentially + + align:start position:0% +zero at row to Z this is essentially + + + align:start position:0% +zero at row to Z this is essentially +like a flat Matrix because like to Z + + align:start position:0% +like a flat Matrix because like to Z + + + align:start position:0% +like a flat Matrix because like to Z +this is just a sphere so this become + + align:start position:0% +this is just a sphere so this become + + + align:start position:0% +this is just a sphere so this become +what this is a + + align:start position:0% +what this is a + + + align:start position:0% +what this is a +sphere + + align:start position:0% +sphere + + + align:start position:0% +sphere +yeah yeah yeah rowal to zero this is + + align:start position:0% +yeah yeah yeah rowal to zero this is + + + align:start position:0% +yeah yeah yeah rowal to zero this is +just like Ting space because this sign + + align:start position:0% +just like Ting space because this sign + + + align:start position:0% +just like Ting space because this sign +row Square become row Square okay so + + align:start position:0% +row Square become row Square okay so + + + align:start position:0% +row Square become row Square okay so +this just become like cre in space in + + align:start position:0% +this just become like cre in space in + + + align:start position:0% +this just become like cre in space in +poate and then you have a time and then + + align:start position:0% +poate and then you have a time and then + + + align:start position:0% +poate and then you have a time and then +this scale factor become one so zal to + + align:start position:0% +this scale factor become one so zal to + + + align:start position:0% +this scale factor become one so zal to +zero just like you have ordinary movi + + align:start position:0% +zero just like you have ordinary movi + + + align:start position:0% +zero just like you have ordinary movi +space + + align:start position:0% +space + + + align:start position:0% +space +time and uh and then and then uh then + + align:start position:0% +time and uh and then and then uh then + + + align:start position:0% +time and uh and then and then uh then +the curvature comes in when you go to + + align:start position:0% +the curvature comes in when you go to + + + align:start position:0% +the curvature comes in when you go to +fight row and then those Factor become + + align:start position:0% +fight row and then those Factor become + + + align:start position:0% +fight row and then those Factor become +important and then you can show yeah + + align:start position:0% +important and then you can show yeah + + + align:start position:0% +important and then you can show yeah +just because of that you can show that + + align:start position:0% +just because of that you can show that + + + align:start position:0% +just because of that you can show that +the massive particle will never actually + + align:start position:0% +the massive particle will never actually + + + align:start position:0% +the massive particle will never actually +travel to the boundary okay always + + align:start position:0% +travel to the boundary okay always + + + align:start position:0% +travel to the boundary okay always +reflected back in some sense you can + + align:start position:0% +reflected back in some sense you can + + + align:start position:0% +reflected back in some sense you can +think of that the massive particle is + + align:start position:0% +think of that the massive particle is + + + align:start position:0% +think of that the massive particle is +always pulled back by the gravitational + + align:start position:0% +always pulled back by the gravitational + + + align:start position:0% +always pulled back by the gravitational +potential okay pull back by gravity poal + + align:start position:0% +potential okay pull back by gravity poal + + + align:start position:0% +potential okay pull back by gravity poal +so so from a from a different point of + + align:start position:0% +so so from a from a different point of + + + align:start position:0% +so so from a from a different point of +view is that another way to say + + align:start position:0% +view is that another way to say + + + align:start position:0% +view is that another way to say +it is a familiar statement which people + + align:start position:0% +it is a familiar statement which people + + + align:start position:0% +it is a familiar statement which people +often + + align:start position:0% +often + + + align:start position:0% +often +make and uh and often can give you great + + align:start position:0% +make and uh and often can give you great + + + align:start position:0% +make and uh and often can give you great +intuition physical + + align:start position:0% +intuition physical + + + align:start position:0% +intuition physical +intuition in in many physical + + align:start position:0% +intuition in in many physical + + + align:start position:0% +intuition in in many physical +problems is that + + align:start position:0% +problems is that + + + align:start position:0% +problems is that +ads is like a confining + + align:start position:0% + + + + align:start position:0% + +box just like a box so things cannot + + align:start position:0% +box just like a box so things cannot + + + align:start position:0% +box just like a box so things cannot +escape from it + + align:start position:0% + + + + align:start position:0% + +okay okay and in in in particular + + align:start position:0% +okay okay and in in in particular + + + align:start position:0% +okay okay and in in in particular +particular the typical curvature radius + + align:start position:0% +particular the typical curvature radius + + + align:start position:0% +particular the typical curvature radius +is + + align:start position:0% +is + + + align:start position:0% +is +R so you can roughly imagine this and + + align:start position:0% +R so you can roughly imagine this and + + + align:start position:0% +R so you can roughly imagine this and +because in the center it's like a flat + + align:start position:0% +because in the center it's like a flat + + + align:start position:0% +because in the center it's like a flat +space so it's more like a box of sides R + + align:start position:0% +space so it's more like a box of sides R + + + align:start position:0% +space so it's more like a box of sides R +okay it's roughly you can horis think of + + align:start position:0% +okay it's roughly you can horis think of + + + align:start position:0% +okay it's roughly you can horis think of +it as a box of sides R yes does it have + + align:start position:0% +it as a box of sides R yes does it have + + + align:start position:0% +it as a box of sides R yes does it have +finite INF volume H this a finite + + align:start position:0% +finite INF volume H this a finite + + + align:start position:0% +finite INF volume H this a finite +infinite volume yeah infinite volume + + align:start position:0% +infinite volume yeah infinite volume + + + align:start position:0% +infinite volume yeah infinite volume +volume yeah but because it's confining + + align:start position:0% +volume yeah but because it's confining + + + align:start position:0% +volume yeah but because it's confining +it most of the particles we only see the + + align:start position:0% +it most of the particles we only see the + + + align:start position:0% +it most of the particles we only see the +sides off so so one question so can we + + align:start position:0% +sides off so so one question so can we + + + align:start position:0% +sides off so so one question so can we +is it correct to say that it's like an + + align:start position:0% +is it correct to say that it's like an + + + align:start position:0% +is it correct to say that it's like an +anti-h harmonic + + align:start position:0% +anti-h harmonic + + + align:start position:0% +anti-h harmonic +tra um like I mean so like I throw if + + align:start position:0% +tra um like I mean so like I throw if + + + align:start position:0% +tra um like I mean so like I throw if +I'm in space and I throw a ball out it's + + align:start position:0% +I'm in space and I throw a ball out it's + + + align:start position:0% +I'm in space and I throw a ball out it's +going to come and hit me back in the + + align:start position:0% +going to come and hit me back in the + + + align:start position:0% +going to come and hit me back in the +head or something like that like it + + align:start position:0% +head or something like that like it + + + align:start position:0% +head or something like that like it +seems like yeah right right yeah we + + align:start position:0% +seems like yeah right right yeah we + + + align:start position:0% +seems like yeah right right yeah we +bounce back yeah um yeah actually our + + align:start position:0% +bounce back yeah um yeah actually our + + + align:start position:0% +bounce back yeah um yeah actually our +own friend Frank whech in the 80s have + + align:start position:0% +own friend Frank whech in the 80s have + + + align:start position:0% +own friend Frank whech in the 80s have +tried to use this ideas this feature to + + align:start position:0% +tried to use this ideas this feature to + + + align:start position:0% +tried to use this ideas this feature to +say maybe this actually + + align:start position:0% +say maybe this actually + + + align:start position:0% +say maybe this actually +it describes + + align:start position:0% +it describes + + + align:start position:0% +it describes +confinement because of if you put a + + align:start position:0% +confinement because of if you put a + + + align:start position:0% +confinement because of if you put a +quock there and they're confined anyway + + align:start position:0% +quock there and they're confined anyway + + + align:start position:0% +quock there and they're confined anyway +um yeah but but but keep this fistic + + align:start position:0% +um yeah but but but keep this fistic + + + align:start position:0% +um yeah but but but keep this fistic +picture in mind because many physical + + align:start position:0% +picture in mind because many physical + + + align:start position:0% +picture in mind because many physical +problems actually if you think of in + + align:start position:0% +problems actually if you think of in + + + align:start position:0% +problems actually if you think of in +terms of this picture become very + + align:start position:0% +terms of this picture become very + + + align:start position:0% +terms of this picture become very +intuitive + + align:start position:0% + + + + align:start position:0% + +okay okay um and + + align:start position:0% +okay okay um and + + + align:start position:0% +okay okay um and +often so you say this is a you say this + + align:start position:0% +often so you say this is a you say this + + + align:start position:0% +often so you say this is a you say this +is the exception for the light Ray but + + align:start position:0% +is the exception for the light Ray but + + + align:start position:0% +is the exception for the light Ray but +often we we impose the reflecting + + align:start position:0% +often we we impose the reflecting + + + align:start position:0% +often we we impose the reflecting +boundary condition on the light Ray and + + align:start position:0% +boundary condition on the light Ray and + + + align:start position:0% +boundary condition on the light Ray and +for the light Ray this is also like a + + align:start position:0% +for the light Ray this is also like a + + + align:start position:0% +for the light Ray this is also like a +box and and you go to the boundary and + + align:start position:0% +box and and you go to the boundary and + + + align:start position:0% +box and and you go to the boundary and +you bounce back Etc + + align:start position:0% +you bounce back Etc + + + align:start position:0% +you bounce back Etc +okay so now let me again just say it but + + align:start position:0% +okay so now let me again just say it but + + + align:start position:0% +okay so now let me again just say it but +you should go back to check + + align:start position:0% +you should go back to check + + + align:start position:0% +you should go back to check +yourself now by looking at the relation + + align:start position:0% +yourself now by looking at the relation + + + align:start position:0% +yourself now by looking at the relation +between + + align:start position:0% +between + + + align:start position:0% +between +here so here is a specific relation + + align:start position:0% +here so here is a specific relation + + + align:start position:0% +here so here is a specific relation +between R and + + align:start position:0% +between R and + + + align:start position:0% +between R and +x and here is a specific relation + + align:start position:0% +x and here is a specific relation + + + align:start position:0% +x and here is a specific relation +between the between this X and this Tow + + align:start position:0% +between the between this X and this Tow + + + align:start position:0% +between the between this X and this Tow +and the this R you can find the relation + + align:start position:0% +and the this R you can find the relation + + + align:start position:0% +and the this R you can find the relation +between the this P coordinate and this + + align:start position:0% +between the this P coordinate and this + + + align:start position:0% +between the this P coordinate and this +global + + align:start position:0% +global + + + align:start position:0% +global +coordinates okay I use a little bit + + align:start position:0% +coordinates okay I use a little bit + + + align:start position:0% +coordinates okay I use a little bit +effort and then you can show + + align:start position:0% +effort and then you can show + + + align:start position:0% +effort and then you can show +yourself then you can show yourself let + + align:start position:0% +yourself then you can show yourself let + + + align:start position:0% +yourself then you can show yourself let +me just draw the + + align:start position:0% +me just draw the + + + align:start position:0% +me just draw the +picture again let me using the same + + align:start position:0% + + + + align:start position:0% + +picture you can show that the p pth + + align:start position:0% +picture you can show that the p pth + + + align:start position:0% +picture you can show that the p pth +cover a wedge say at Le in this + + align:start position:0% +cover a wedge say at Le in this + + + align:start position:0% +cover a wedge say at Le in this +cross-section the P patch cover a + + align:start position:0% +cross-section the P patch cover a + + + align:start position:0% +cross-section the P patch cover a +cross-section uh uh of This Global ideas + + align:start position:0% +cross-section uh uh of This Global ideas + + + align:start position:0% +cross-section uh uh of This Global ideas +okay so so here it's + + align:start position:0% +okay so so here it's + + + align:start position:0% +okay so so here it's +tall equal to minus pi and here is t + + align:start position:0% +tall equal to minus pi and here is t + + + align:start position:0% +tall equal to minus pi and here is t +equal to plus pi and here say tal to + + align:start position:0% +equal to plus pi and here say tal to + + + align:start position:0% +equal to plus pi and here say tal to +zero and uh and in the in this P patch + + align:start position:0% +zero and uh and in the in this P patch + + + align:start position:0% +zero and uh and in the in this P patch +and then this n become IAL to zero and + + align:start position:0% +and then this n become IAL to zero and + + + align:start position:0% +and then this n become IAL to zero and +tal to minus + + align:start position:0% +tal to minus + + + align:start position:0% +tal to minus +infinity and this nine become I equal to + + align:start position:0% +infinity and this nine become I equal to + + + align:start position:0% +infinity and this nine become I equal to +Z and t plus + + align:start position:0% +Z and t plus + + + align:start position:0% +Z and t plus +infinity okay plus + + align:start position:0% +infinity okay plus + + + align:start position:0% +infinity okay plus +infinity and uh so so the time + + align:start position:0% +infinity and uh so so the time + + + align:start position:0% +infinity and uh so so the time +essentially goes around like + + align:start position:0% +essentially goes around like + + + align:start position:0% +essentially goes around like +this time go around like this and and + + align:start position:0% +this time go around like this and and + + + align:start position:0% +this time go around like this and and +and this line corresponding to t equal + + align:start position:0% +and this line corresponding to t equal + + + align:start position:0% +and this line corresponding to t equal +to Z okay so tal Z and tal to Z + + align:start position:0% +to Z okay so tal Z and tal to Z + + + align:start position:0% +to Z okay so tal Z and tal to Z +coincides and then you go to minus + + align:start position:0% +coincides and then you go to minus + + + align:start position:0% +coincides and then you go to minus +infinity Rota to that + + align:start position:0% +infinity Rota to that + + + align:start position:0% +infinity Rota to that +so so and the constant R + + align:start position:0% + + + + align:start position:0% + +surface so this is the constant R + + align:start position:0% +surface so this is the constant R + + + align:start position:0% +surface so this is the constant R +surface in the P + + align:start position:0% + + + + align:start position:0% + +coordinate goes like this so the time + + align:start position:0% +coordinate goes like this so the time + + + align:start position:0% +coordinate goes like this so the time +goes up okay and you can check yourself + + align:start position:0% +goes up okay and you can check yourself + + + align:start position:0% +goes up okay and you can check yourself +uh just by working out the relation + + align:start position:0% +uh just by working out the relation + + + align:start position:0% +uh just by working out the relation +between those coordinates through the + + align:start position:0% +between those coordinates through the + + + align:start position:0% +between those coordinates through the +a uh you mean this is uh WRA on the CER + + align:start position:0% +a uh you mean this is uh WRA on the CER + + + align:start position:0% +a uh you mean this is uh WRA on the CER +no no no no I'm just saying uh which + + align:start position:0% +no no no no I'm just saying uh which + + + align:start position:0% +no no no no I'm just saying uh which +this is + + align:start position:0% +this is + + + align:start position:0% +this is +picture just within this crosssection I + + align:start position:0% +picture just within this crosssection I + + + align:start position:0% +picture just within this crosssection I +can look at this crosssection I see how + + align:start position:0% +can look at this crosssection I see how + + + align:start position:0% +can look at this crosssection I see how +this translate into P coordinates and + + align:start position:0% +this translate into P coordinates and + + + align:start position:0% +this translate into P coordinates and +that's what's happening a p coordinate + + align:start position:0% +that's what's happening a p coordinate + + + align:start position:0% +that's what's happening a p coordinate +cover this part + + align:start position:0% +cover this part + + + align:start position:0% +cover this part +okay okay cover this part I can also + + align:start position:0% +okay okay cover this part I can also + + + align:start position:0% +okay okay cover this part I can also +draw a more fancy picture + + align:start position:0% +draw a more fancy picture + + + align:start position:0% +draw a more fancy picture +here then then roughly uh what you can + + align:start position:0% +here then then roughly uh what you can + + + align:start position:0% +here then then roughly uh what you can +show is that the in this General + + align:start position:0% +show is that the in this General + + + align:start position:0% +show is that the in this General +picture is said the P patch cover + + align:start position:0% +picture is said the P patch cover + + + align:start position:0% +picture is said the P patch cover +something like this + + align:start position:0% +something like this + + + align:start position:0% +something like this +okay and the region between these two + + align:start position:0% +okay and the region between these two + + + align:start position:0% +okay and the region between these two +lines so so this is a spatial Infinity + + align:start position:0% +lines so so this is a spatial Infinity + + + align:start position:0% +lines so so this is a spatial Infinity +of the in in the in this P + + align:start position:0% +of the in in the in this P + + + align:start position:0% +of the in in the in this P +patch the boundary is minkovski space + + align:start position:0% +patch the boundary is minkovski space + + + align:start position:0% +patch the boundary is minkovski space +time so + + align:start position:0% + + + + align:start position:0% + +so so you see so the p p cover like that + + align:start position:0% +so so you see so the p p cover like that + + + align:start position:0% +so so you see so the p p cover like that +and and then and then this is a spal + + align:start position:0% +and and then and then this is a spal + + + align:start position:0% +and and then and then this is a spal +Infinity of the movi space time this is + + align:start position:0% +Infinity of the movi space time this is + + + align:start position:0% +Infinity of the movi space time this is +the time infinity and time P movi space + + align:start position:0% +the time infinity and time P movi space + + + align:start position:0% +the time infinity and time P movi space +time okay so so you I urge you to do it + + align:start position:0% +time okay so so you I urge you to do it + + + align:start position:0% +time okay so so you I urge you to do it +yourself because this kind of thing uh + + align:start position:0% +yourself because this kind of thing uh + + + align:start position:0% +yourself because this kind of thing uh +you really have to work through yourself + + align:start position:0% +you really have to work through yourself + + + align:start position:0% +you really have to work through yourself +to to have intuitive feeling for it but + + align:start position:0% +to to have intuitive feeling for it but + + + align:start position:0% +to to have intuitive feeling for it but +this is a + + align:start position:0% +this is a + + + align:start position:0% +this is a +picture once you work out yourself you + + align:start position:0% +picture once you work out yourself you + + + align:start position:0% +picture once you work out yourself you +compare with my picture and then you + + align:start position:0% +compare with my picture and then you + + + align:start position:0% +compare with my picture and then you +will understand + + align:start position:0% +will understand + + + align:start position:0% +will understand +okay so I we stop here + + align:start position:0% +okay so I we stop here + + + align:start position:0% +okay so I we stop here +today so so in some sense yeah let me + + align:start position:0% +today so so in some sense yeah let me + + + align:start position:0% +today so so in some sense yeah let me +just say one one more sentence this + + align:start position:0% +just say one one more sentence this + + + align:start position:0% +just say one one more sentence this +extended ideas contain infinite copies + + align:start position:0% +extended ideas contain infinite copies + + + align:start position:0% +extended ideas contain infinite copies +of this P patch + + align:start position:0% +of this P patch + + + align:start position:0% +of this P patch +okay \ No newline at end of file diff --git a/466icY9MQp4.txt b/466icY9MQp4.txt new file mode 100644 index 0000000000000000000000000000000000000000..52800aaed7c19fc8b9efee688908b1766ee490e5 --- /dev/null +++ b/466icY9MQp4.txt @@ -0,0 +1,8139 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +view additional materials from hundreds + + align:start position:0% +view additional materials from hundreds + + + align:start position:0% +view additional materials from hundreds +of MIT courses visit MIT open courseware + + align:start position:0% +of MIT courses visit MIT open courseware + + + align:start position:0% +of MIT courses visit MIT open courseware +at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu I wanted to say a few things + + align:start position:0% +ocw.mit.edu I wanted to say a few things + + + align:start position:0% +ocw.mit.edu I wanted to say a few things +about the end + + align:start position:0% +about the end + + + align:start position:0% +about the end +of what was meant to be the the end of + + align:start position:0% +of what was meant to be the the end of + + + align:start position:0% +of what was meant to be the the end of +class 6 + + align:start position:0% +class 6 + + + align:start position:0% +class 6 +uh it's chapter 7 in the book + + align:start position:0% + + + + align:start position:0% + +uh but we + + align:start position:0% +uh but we + + + align:start position:0% +uh but we +were it was meant to be a overview of + + align:start position:0% +were it was meant to be a overview of + + + align:start position:0% +were it was meant to be a overview of +the forbrain and I + + align:start position:0% +the forbrain and I + + + align:start position:0% +the forbrain and I +was at the end here I was talking about + + align:start position:0% +was at the end here I was talking about + + + align:start position:0% +was at the end here I was talking about +the well we got to through the limic + + align:start position:0% +the well we got to through the limic + + + align:start position:0% +the well we got to through the limic +system and then I wanted to say a little + + align:start position:0% +system and then I wanted to say a little + + + align:start position:0% +system and then I wanted to say a little +bit about the neocortex + + align:start position:0% +bit about the neocortex + + + align:start position:0% +bit about the neocortex +so this picture here just gives a little + + align:start position:0% +so this picture here just gives a little + + + align:start position:0% +so this picture here just gives a little +outline of meant to show the addition of + + align:start position:0% +outline of meant to show the addition of + + + align:start position:0% +outline of meant to show the addition of +neocortex + + align:start position:0% +neocortex + + + align:start position:0% +neocortex +and it was a slide where I'm showing + + align:start position:0% +and it was a slide where I'm showing + + + align:start position:0% +and it was a slide where I'm showing +that the lyic system is one way to + + align:start position:0% +that the lyic system is one way to + + + align:start position:0% +that the lyic system is one way to +define It Is by connections to the + + align:start position:0% +define It Is by connections to the + + + align:start position:0% +define It Is by connections to the +hypothalamus but now when we get to + + align:start position:0% +hypothalamus but now when we get to + + + align:start position:0% +hypothalamus but now when we get to +neocortex the first topic that we always + + align:start position:0% +neocortex the first topic that we always + + + align:start position:0% +neocortex the first topic that we always +think of neocortex is so important in + + align:start position:0% +think of neocortex is so important in + + + align:start position:0% +think of neocortex is so important in +learning and I want to point out that it + + align:start position:0% +learning and I want to point out that it + + + align:start position:0% +learning and I want to point out that it +was in the early olda factory system + + align:start position:0% +was in the early olda factory system + + + align:start position:0% +was in the early olda factory system +long before there was any + + align:start position:0% +long before there was any + + + align:start position:0% +long before there was any +neocortex there evolved these two types + + align:start position:0% +neocortex there evolved these two types + + + align:start position:0% +neocortex there evolved these two types +two types of learning that have renamed + + align:start position:0% +two types of learning that have renamed + + + align:start position:0% +two types of learning that have renamed +the two major types of learning that do + + align:start position:0% +the two major types of learning that do + + + align:start position:0% +the two major types of learning that do +involve neocortex in uh in + + align:start position:0% +involve neocortex in uh in + + + align:start position:0% +involve neocortex in uh in +mammals including human beings two + + align:start position:0% +mammals including human beings two + + + align:start position:0% +mammals including human beings two +different kinds of learning so what are + + align:start position:0% +different kinds of learning so what are + + + align:start position:0% +different kinds of learning so what are +these two different kinds of learning + + align:start position:0% +these two different kinds of learning + + + align:start position:0% +these two different kinds of learning +and I'm talking + + align:start position:0% +and I'm talking + + + align:start position:0% +and I'm talking +about you can think of them in terms of + + align:start position:0% +about you can think of them in terms of + + + align:start position:0% +about you can think of them in terms of +the structures that are involved or you + + align:start position:0% +the structures that are involved or you + + + align:start position:0% +the structures that are involved or you +can give them a name the types of + + align:start position:0% +can give them a name the types of + + + align:start position:0% +can give them a name the types of +learning you know what I'm talking about + + align:start position:0% +learning you know what I'm talking about + + + align:start position:0% +learning you know what I'm talking about +any of + + align:start position:0% +any of + + + align:start position:0% +any of +you remember I talked about the early + + align:start position:0% +you remember I talked about the early + + + align:start position:0% +you remember I talked about the early +evolution of old faction and how the + + align:start position:0% +evolution of old faction and how the + + + align:start position:0% +evolution of old faction and how the +connections were with this ventral most + + align:start position:0% +connections were with this ventral most + + + align:start position:0% +connections were with this ventral most +part of the striatum Corpus striatum and + + align:start position:0% +part of the striatum Corpus striatum and + + + align:start position:0% +part of the striatum Corpus striatum and +I said that the important thing about + + align:start position:0% +I said that the important thing about + + + align:start position:0% +I said that the important thing about +those connections was that they were + + align:start position:0% +those connections was that they were + + + align:start position:0% +those connections was that they were +plastic they could change that's how + + align:start position:0% +plastic they could change that's how + + + align:start position:0% +plastic they could change that's how +animals learn + + align:start position:0% + + + + align:start position:0% + +to to like certain uh smells and not + + align:start position:0% +to to like certain uh smells and not + + + align:start position:0% +to to like certain uh smells and not +like others they identified objects that + + align:start position:0% +like others they identified objects that + + + align:start position:0% +like others they identified objects that +way but they did all another thing too + + align:start position:0% +way but they did all another thing too + + + align:start position:0% +way but they did all another thing too +uh different regions they went to + + align:start position:0% +uh different regions they went to + + + align:start position:0% +uh different regions they went to +smelled + + align:start position:0% +smelled + + + align:start position:0% +smelled +different so without any Vision there + + align:start position:0% +different so without any Vision there + + + align:start position:0% +different so without any Vision there +were two kinds of learning that were + + align:start position:0% +were two kinds of learning that were + + + align:start position:0% +were two kinds of learning that were +possible places + + align:start position:0% +possible places + + + align:start position:0% +possible places +that were good or bad for them according + + align:start position:0% +that were good or bad for them according + + + align:start position:0% +that were good or bad for them according +to the feedback they get and the objects + + align:start position:0% +to the feedback they get and the objects + + + align:start position:0% +to the feedback they get and the objects +in those places that could be good or + + align:start position:0% +in those places that could be good or + + + align:start position:0% +in those places that could be good or +bad to eat for example they also of + + align:start position:0% +bad to eat for example they also of + + + align:start position:0% +bad to eat for example they also of +course could smell predators and that's + + align:start position:0% +course could smell predators and that's + + + align:start position:0% +course could smell predators and that's +still true in many + + align:start position:0% + + + + align:start position:0% + +mammals okay so this is the way I + + align:start position:0% +mammals okay so this is the way I + + + align:start position:0% +mammals okay so this is the way I +summarized it learned object preferences + + align:start position:0% +summarized it learned object preferences + + + align:start position:0% +summarized it learned object preferences +with + + align:start position:0% +with + + + align:start position:0% +with +identification of objects according to + + align:start position:0% +identification of objects according to + + + align:start position:0% +identification of objects according to +whether they're good or bad and Place + + align:start position:0% +whether they're good or bad and Place + + + align:start position:0% +whether they're good or bad and Place +Learning identification and memory of + + align:start position:0% +Learning identification and memory of + + + align:start position:0% +Learning identification and memory of +good places and bad + + align:start position:0% +good places and bad + + + align:start position:0% +good places and bad +places the first one is stodal dependent + + align:start position:0% +places the first one is stodal dependent + + + align:start position:0% +places the first one is stodal dependent +and that remains true even though the + + align:start position:0% +and that remains true even though the + + + align:start position:0% +and that remains true even though the +habits formed aren't dependent on so + + align:start position:0% +habits formed aren't dependent on so + + + align:start position:0% +habits formed aren't dependent on so +much on Al faction in in primates + + align:start position:0% +much on Al faction in in primates + + + align:start position:0% +much on Al faction in in primates +they're mostly dependent on the other + + align:start position:0% +they're mostly dependent on the other + + + align:start position:0% +they're mostly dependent on the other +senses but Al faction is still important + + align:start position:0% +senses but Al faction is still important + + + align:start position:0% +senses but Al faction is still important +the other is Place Learning and that has + + align:start position:0% +the other is Place Learning and that has + + + align:start position:0% +the other is Place Learning and that has +become critical for what humans usually + + align:start position:0% +become critical for what humans usually + + + align:start position:0% +become critical for what humans usually +think of when we think of memory + + align:start position:0% +think of when we think of memory + + + align:start position:0% +think of when we think of memory +long-term memory + + align:start position:0% + + + + align:start position:0% + +formation okay and that will be a theme + + align:start position:0% +formation okay and that will be a theme + + + align:start position:0% +formation okay and that will be a theme +uh that will recur in the + + align:start position:0% + + + + align:start position:0% + +class and what is the part of the brain + + align:start position:0% +class and what is the part of the brain + + + align:start position:0% +class and what is the part of the brain +involved here we always think of + + align:start position:0% +involved here we always think of + + + align:start position:0% +involved here we always think of +hippocampus but in many animals long + + align:start position:0% +hippocampus but in many animals long + + + align:start position:0% +hippocampus but in many animals long +before you could really identify + + align:start position:0% +before you could really identify + + + align:start position:0% +before you could really identify +something that looked like a a seahorse + + align:start position:0% +something that looked like a a seahorse + + + align:start position:0% +something that looked like a a seahorse +a HP campus it was part of the P it was + + align:start position:0% +a HP campus it was part of the P it was + + + align:start position:0% +a HP campus it was part of the P it was +the medial p okay and in a in a picture + + align:start position:0% +the medial p okay and in a in a picture + + + align:start position:0% +the medial p okay and in a in a picture +like this it's this part + + align:start position:0% +like this it's this part + + + align:start position:0% +like this it's this part +here that's meant to be medial it's a + + align:start position:0% +here that's meant to be medial it's a + + + align:start position:0% +here that's meant to be medial it's a +little hard to show medial and lateral + + align:start position:0% +little hard to show medial and lateral + + + align:start position:0% +little hard to show medial and lateral +in a picture like this but it's part of + + align:start position:0% +in a picture like this but it's part of + + + align:start position:0% +in a picture like this but it's part of +the lyic system connected to + + align:start position:0% +the lyic system connected to + + + align:start position:0% +the lyic system connected to +hypothalamus and we're going to discuss + + align:start position:0% +hypothalamus and we're going to discuss + + + align:start position:0% +hypothalamus and we're going to discuss +later why that came to be true how that + + align:start position:0% +later why that came to be true how that + + + align:start position:0% +later why that came to be true how that +evolved there are good reasons why we + + align:start position:0% +evolved there are good reasons why we + + + align:start position:0% +evolved there are good reasons why we +became so dependent on parts of the + + align:start position:0% +became so dependent on parts of the + + + align:start position:0% +became so dependent on parts of the +limic system for our + + align:start position:0% +limic system for our + + + align:start position:0% +limic system for our +memories + + align:start position:0% +memories + + + align:start position:0% +memories +all + + align:start position:0% + + + + align:start position:0% + +right so now with neoc cortic + + align:start position:0% +right so now with neoc cortic + + + align:start position:0% +right so now with neoc cortic +expansion there were new sensory + + align:start position:0% +expansion there were new sensory + + + align:start position:0% +expansion there were new sensory +Pathways that became prominent they were + + align:start position:0% +Pathways that became prominent they were + + + align:start position:0% +Pathways that became prominent they were +rapid more rapidly conducting than the + + align:start position:0% +rapid more rapidly conducting than the + + + align:start position:0% +rapid more rapidly conducting than the +spinal reticular Pathways and the + + align:start position:0% +spinal reticular Pathways and the + + + align:start position:0% +spinal reticular Pathways and the +spinothalamic pathways and sending + + align:start position:0% +spinothalamic pathways and sending + + + align:start position:0% +spinothalamic pathways and sending +information to the to the + + align:start position:0% +information to the to the + + + align:start position:0% +information to the to the +Forin now we're talking mainly about + + align:start position:0% +Forin now we're talking mainly about + + + align:start position:0% +Forin now we're talking mainly about +Pathways to + + align:start position:0% +Pathways to + + + align:start position:0% +Pathways to +neocortex okay + + align:start position:0% +neocortex okay + + + align:start position:0% +neocortex okay +and here I'm just showing the addition + + align:start position:0% +and here I'm just showing the addition + + + align:start position:0% +and here I'm just showing the addition +of Cortex and then here's I've altered + + align:start position:0% +of Cortex and then here's I've altered + + + align:start position:0% +of Cortex and then here's I've altered +this diagram here to show neocortex up + + align:start position:0% +this diagram here to show neocortex up + + + align:start position:0% +this diagram here to show neocortex up +here there's the medial pallum so I made + + align:start position:0% +here there's the medial pallum so I made + + + align:start position:0% +here there's the medial pallum so I made +it look like a + + align:start position:0% +it look like a + + + align:start position:0% +it look like a +hippocampus okay so that's part of the + + align:start position:0% +hippocampus okay so that's part of the + + + align:start position:0% +hippocampus okay so that's part of the +limic system which is all of this in the + + align:start position:0% +limic system which is all of this in the + + + align:start position:0% +limic system which is all of this in the +diagram and this is really also lyic but + + align:start position:0% +diagram and this is really also lyic but + + + align:start position:0% +diagram and this is really also lyic but +it's old factory the factory parts of + + align:start position:0% +it's old factory the factory parts of + + + align:start position:0% +it's old factory the factory parts of +the lyic system they're lyic because + + align:start position:0% +the lyic system they're lyic because + + + align:start position:0% +the lyic system they're lyic because +they're closely connected with + + align:start position:0% +they're closely connected with + + + align:start position:0% +they're closely connected with +hypothalamus in fact many animals + + align:start position:0% +hypothalamus in fact many animals + + + align:start position:0% +hypothalamus in fact many animals +actually have direct ol factory + + align:start position:0% +actually have direct ol factory + + + align:start position:0% +actually have direct ol factory +connections to the + + align:start position:0% +connections to the + + + align:start position:0% +connections to the +hypothalamus all right so now the two + + align:start position:0% +hypothalamus all right so now the two + + + align:start position:0% +hypothalamus all right so now the two +Pathways I don't know why but students + + align:start position:0% +Pathways I don't know why but students + + + align:start position:0% +Pathways I don't know why but students +always find it difficult to to memorize + + align:start position:0% +always find it difficult to to memorize + + + align:start position:0% +always find it difficult to to memorize +this we talked about spinal reticular we + + align:start position:0% +this we talked about spinal reticular we + + + align:start position:0% +this we talked about spinal reticular we +talked about spinal tham now here is + + align:start position:0% +talked about spinal tham now here is + + + align:start position:0% +talked about spinal tham now here is +another + + align:start position:0% +another + + + align:start position:0% +another +system that has a number of branches but + + align:start position:0% +system that has a number of branches but + + + align:start position:0% +system that has a number of branches but +it's it many more of its axons go all + + align:start position:0% +it's it many more of its axons go all + + + align:start position:0% +it's it many more of its axons go all +the way to the phons so it's a pathway + + align:start position:0% +the way to the phons so it's a pathway + + + align:start position:0% +the way to the phons so it's a pathway +to the neocortex by way of the felons + + align:start position:0% +to the neocortex by way of the felons + + + align:start position:0% +to the neocortex by way of the felons +and I've shown here that the first part + + align:start position:0% +and I've shown here that the first part + + + align:start position:0% +and I've shown here that the first part +of it is the dorsal + + align:start position:0% +of it is the dorsal + + + align:start position:0% +of it is the dorsal +columns they are actually axons of + + align:start position:0% +columns they are actually axons of + + + align:start position:0% +columns they are actually axons of +primary Sensory neurons so here they + + align:start position:0% +primary Sensory neurons so here they + + + align:start position:0% +primary Sensory neurons so here they +start out in the skin specialized in + + align:start position:0% +start out in the skin specialized in + + + align:start position:0% +start out in the skin specialized in +organs + + align:start position:0% +organs + + + align:start position:0% +organs +like Pini and cor pusle sensitive Define + + align:start position:0% +like Pini and cor pusle sensitive Define + + + align:start position:0% +like Pini and cor pusle sensitive Define +touch and things like that in the skin + + align:start position:0% +touch and things like that in the skin + + + align:start position:0% +touch and things like that in the skin +okay and there's its axon it does Branch + + align:start position:0% +okay and there's its axon it does Branch + + + align:start position:0% +okay and there's its axon it does Branch +it connects in the spinal cord too but + + align:start position:0% +it connects in the spinal cord too but + + + align:start position:0% +it connects in the spinal cord too but +it ascends all the way to the top of the + + align:start position:0% +it ascends all the way to the top of the + + + align:start position:0% +it ascends all the way to the top of the +spinal cord and some Anatomy texts say + + align:start position:0% +spinal cord and some Anatomy texts say + + + align:start position:0% +spinal cord and some Anatomy texts say +coddle end of the hbr it's a little bit + + align:start position:0% +coddle end of the hbr it's a little bit + + + align:start position:0% +coddle end of the hbr it's a little bit +arbitrary where you mark that Division I + + align:start position:0% +arbitrary where you mark that Division I + + + align:start position:0% +arbitrary where you mark that Division I +follow NAA he puts it at the very top of + + align:start position:0% +follow NAA he puts it at the very top of + + + align:start position:0% +follow NAA he puts it at the very top of +the spinal cord that's the dorsal column + + align:start position:0% +the spinal cord that's the dorsal column + + + align:start position:0% +the spinal cord that's the dorsal column +nuclei as you go we we'll see I'll we'll + + align:start position:0% +nuclei as you go we we'll see I'll we'll + + + align:start position:0% +nuclei as you go we we'll see I'll we'll +be talking about that very soon you'll + + align:start position:0% +be talking about that very soon you'll + + + align:start position:0% +be talking about that very soon you'll +see the call + + align:start position:0% +see the call + + + align:start position:0% +see the call +nuclea okay representing all different + + align:start position:0% +nuclea okay representing all different + + + align:start position:0% +nuclea okay representing all different +parts of the body except the face but in + + align:start position:0% +parts of the body except the face but in + + + align:start position:0% +parts of the body except the face but in +fact the face is represented there too + + align:start position:0% +fact the face is represented there too + + + align:start position:0% +fact the face is represented there too +and I will show you how okay but that is + + align:start position:0% +and I will show you how okay but that is + + + align:start position:0% +and I will show you how okay but that is +the first synaps in the pathway so it's + + align:start position:0% +the first synaps in the pathway so it's + + + align:start position:0% +the first synaps in the pathway so it's +it it conducts rapidly they tend to be + + align:start position:0% +it it conducts rapidly they tend to be + + + align:start position:0% +it it conducts rapidly they tend to be +all mated fairly large + + align:start position:0% +all mated fairly large + + + align:start position:0% +all mated fairly large +accs so this pathway now from the dorsal + + align:start position:0% +accs so this pathway now from the dorsal + + + align:start position:0% +accs so this pathway now from the dorsal +column nuclei Decat right here + + align:start position:0% +column nuclei Decat right here + + + align:start position:0% +column nuclei Decat right here +here and ascends in a pathway through + + align:start position:0% +here and ascends in a pathway through + + + align:start position:0% +here and ascends in a pathway through +the hindbrain and midbrain that we call + + align:start position:0% +the hindbrain and midbrain that we call + + + align:start position:0% +the hindbrain and midbrain that we call +the medial liscus the medial ribbon okay + + align:start position:0% +the medial liscus the medial ribbon okay + + + align:start position:0% +the medial liscus the medial ribbon okay +that goes directly to the + + align:start position:0% +that goes directly to the + + + align:start position:0% +that goes directly to the +fals there are a + + align:start position:0% +fals there are a + + + align:start position:0% +fals there are a +few branches that go into reticular + + align:start position:0% +few branches that go into reticular + + + align:start position:0% +few branches that go into reticular +formation but the main pathway goes + + align:start position:0% +formation but the main pathway goes + + + align:start position:0% +formation but the main pathway goes +right to the fs and those thalamic cells + + align:start position:0% +right to the fs and those thalamic cells + + + align:start position:0% +right to the fs and those thalamic cells +connect to cicin Tre neocortex that's + + align:start position:0% +connect to cicin Tre neocortex that's + + + align:start position:0% +connect to cicin Tre neocortex that's +how our sensory cortex gets its major + + align:start position:0% +how our sensory cortex gets its major + + + align:start position:0% +how our sensory cortex gets its major +input it does get input through the + + align:start position:0% +input it does get input through the + + + align:start position:0% +input it does get input through the +spinal thalamic pathway and even a + + align:start position:0% +spinal thalamic pathway and even a + + + align:start position:0% +spinal thalamic pathway and even a +little bit spinal reticular also but + + align:start position:0% +little bit spinal reticular also but + + + align:start position:0% +little bit spinal reticular also but +this at least for fine touch very + + align:start position:0% +this at least for fine touch very + + + align:start position:0% +this at least for fine touch very +discriminative + + align:start position:0% +discriminative + + + align:start position:0% +discriminative +touch especially the touch that we use + + align:start position:0% +touch especially the touch that we use + + + align:start position:0% +touch especially the touch that we use +when we're moving our fingers over + + align:start position:0% +when we're moving our fingers over + + + align:start position:0% +when we're moving our fingers over +something very dependent on this pathway + + align:start position:0% +something very dependent on this pathway + + + align:start position:0% +something very dependent on this pathway +all right so here is the top view it + + align:start position:0% +all right so here is the top view it + + + align:start position:0% +all right so here is the top view it +shows the same thing the primary sensory + + align:start position:0% +shows the same thing the primary sensory + + + align:start position:0% +shows the same thing the primary sensory +neuron and it's axon terminating if this + + align:start position:0% +neuron and it's axon terminating if this + + + align:start position:0% +neuron and it's axon terminating if this +is in the lumbar enlargement so let's + + align:start position:0% +is in the lumbar enlargement so let's + + + align:start position:0% +is in the lumbar enlargement so let's +say it's coming from the foot it would + + align:start position:0% +say it's coming from the foot it would + + + align:start position:0% +say it's coming from the foot it would +go to the + + align:start position:0% +go to the + + + align:start position:0% +go to the +medial dorsal column nucleus there's two + + align:start position:0% +medial dorsal column nucleus there's two + + + align:start position:0% +medial dorsal column nucleus there's two +nuclei there the medial one represents + + align:start position:0% +nuclei there the medial one represents + + + align:start position:0% +nuclei there the medial one represents +the lower body and the upper one + + align:start position:0% +the lower body and the upper one + + + align:start position:0% +the lower body and the upper one +represents the arms and chest okay and + + align:start position:0% +represents the arms and chest okay and + + + align:start position:0% +represents the arms and chest okay and +there's the axon that Decat the axon of + + align:start position:0% +there's the axon that Decat the axon of + + + align:start position:0% +there's the axon that Decat the axon of +the medial oniscus starts in the dorsal + + align:start position:0% +the medial oniscus starts in the dorsal + + + align:start position:0% +the medial oniscus starts in the dorsal +column nuclei crosses over goes of the + + align:start position:0% +column nuclei crosses over goes of the + + + align:start position:0% +column nuclei crosses over goes of the +thalamus so it's a cross + + align:start position:0% +thalamus so it's a cross + + + align:start position:0% +thalamus so it's a cross +pathway so that all evolved after the + + align:start position:0% +pathway so that all evolved after the + + + align:start position:0% +pathway so that all evolved after the +crossing + + align:start position:0% +crossing + + + align:start position:0% +crossing +evolved which was admittedly very early + + align:start position:0% +evolved which was admittedly very early + + + align:start position:0% +evolved which was admittedly very early +okay very early + + align:start position:0% + + + + align:start position:0% + +cordat but if we look at the most + + align:start position:0% +cordat but if we look at the most + + + align:start position:0% +cordat but if we look at the most +ancient ones we look at hagfish we look + + align:start position:0% +ancient ones we look at hagfish we look + + + align:start position:0% +ancient ones we look at hagfish we look +at Sea lrey they don't have any pathway + + align:start position:0% +at Sea lrey they don't have any pathway + + + align:start position:0% +at Sea lrey they don't have any pathway +resembling this in fact most mammals + + align:start position:0% +resembling this in fact most mammals + + + align:start position:0% +resembling this in fact most mammals +don't have much of a pathway that's like + + align:start position:0% +don't have much of a pathway that's like + + + align:start position:0% +don't have much of a pathway that's like +this one it's the mammals this becomes + + align:start position:0% +this one it's the mammals this becomes + + + align:start position:0% +this one it's the mammals this becomes +prominent and other Advanced vertebrates + + align:start position:0% +prominent and other Advanced vertebrates + + + align:start position:0% +prominent and other Advanced vertebrates +like birds + + align:start position:0% +like birds + + + align:start position:0% +like birds +okay and now along with that you get + + align:start position:0% +okay and now along with that you get + + + align:start position:0% +okay and now along with that you get +descending Pathways coming down from + + align:start position:0% +descending Pathways coming down from + + + align:start position:0% +descending Pathways coming down from +those ca regions and one of the C + + align:start position:0% +those ca regions and one of the C + + + align:start position:0% +those ca regions and one of the C +sensory CA sensory regions became more + + align:start position:0% +sensory CA sensory regions became more + + + align:start position:0% +sensory CA sensory regions became more +specialized for controlling fine + + align:start position:0% +specialized for controlling fine + + + align:start position:0% +specialized for controlling fine +movement that was the motor + + align:start position:0% +movement that was the motor + + + align:start position:0% +movement that was the motor +CeX okay so I'm showing it here the side + + align:start position:0% +CeX okay so I'm showing it here the side + + + align:start position:0% +CeX okay so I'm showing it here the side +view and I'm depi two neurons for a good + + align:start position:0% +view and I'm depi two neurons for a good + + + align:start position:0% +view and I'm depi two neurons for a good +reason because I want to point out that + + align:start position:0% +reason because I want to point out that + + + align:start position:0% +reason because I want to point out that +the SM sensory what we call sensory + + align:start position:0% +the SM sensory what we call sensory + + + align:start position:0% +the SM sensory what we call sensory +cortex and motor cortex both have + + align:start position:0% +cortex and motor cortex both have + + + align:start position:0% +cortex and motor cortex both have +Pathways to the spinal + + align:start position:0% +Pathways to the spinal + + + align:start position:0% +Pathways to the spinal +cord here's the one you're probably most + + align:start position:0% +cord here's the one you're probably most + + + align:start position:0% +cord here's the one you're probably most +familiar with comes from motor cortex it + + align:start position:0% +familiar with comes from motor cortex it + + + align:start position:0% +familiar with comes from motor cortex it +does have some not note that there is + + align:start position:0% +does have some not note that there is + + + align:start position:0% +does have some not note that there is +branches to the striatum to the thalamus + + align:start position:0% +branches to the striatum to the thalamus + + + align:start position:0% +branches to the striatum to the thalamus +to the midbrain to the hindbrain + + align:start position:0% +to the midbrain to the hindbrain + + + align:start position:0% +to the midbrain to the hindbrain +especially to The Ponds but it goes all + + align:start position:0% +especially to The Ponds but it goes all + + + align:start position:0% +especially to The Ponds but it goes all +the way down to the spinal cord where + + align:start position:0% +the way down to the spinal cord where + + + align:start position:0% +the way down to the spinal cord where +most of the axons in on interneurons in + + align:start position:0% +most of the axons in on interneurons in + + + align:start position:0% +most of the axons in on interneurons in +the ventral horn okay a few of them as I + + align:start position:0% +the ventral horn okay a few of them as I + + + align:start position:0% +the ventral horn okay a few of them as I +show here go directly the motor neurons + + align:start position:0% +show here go directly the motor neurons + + + align:start position:0% +show here go directly the motor neurons +now this The Meta sensory cortex has + + align:start position:0% +now this The Meta sensory cortex has + + + align:start position:0% +now this The Meta sensory cortex has +similarly descending Pathways all the + + align:start position:0% +similarly descending Pathways all the + + + align:start position:0% +similarly descending Pathways all the +way to the spinal cord but these + + align:start position:0% +way to the spinal cord but these + + + align:start position:0% +way to the spinal cord but these +terminate in the dorsal horn okay part + + align:start position:0% +terminate in the dorsal horn okay part + + + align:start position:0% +terminate in the dorsal horn okay part +of the spinal cord that gets sensory + + align:start position:0% +of the spinal cord that gets sensory + + + align:start position:0% +of the spinal cord that gets sensory +input from the dorsal Roots we'll show + + align:start position:0% +input from the dorsal Roots we'll show + + + align:start position:0% +input from the dorsal Roots we'll show +the adult we'll be talking a little more + + align:start position:0% +the adult we'll be talking a little more + + + align:start position:0% +the adult we'll be talking a little more +about that + + align:start position:0% +about that + + + align:start position:0% +about that +that very soon okay so and here's shows + + align:start position:0% +that very soon okay so and here's shows + + + align:start position:0% +that very soon okay so and here's shows +that that of course has to be a + + align:start position:0% +that that of course has to be a + + + align:start position:0% +that that of course has to be a +decoating pathway too because we know + + align:start position:0% +decoating pathway too because we know + + + align:start position:0% +decoating pathway too because we know +that the opposite side of the body is + + align:start position:0% + + + + align:start position:0% + +represented this is the left side it's + + align:start position:0% +represented this is the left side it's + + + align:start position:0% +represented this is the left side it's +representing the right side of the brain + + align:start position:0% +representing the right side of the brain + + + align:start position:0% +representing the right side of the brain +so that pathway Decat too at about the + + align:start position:0% +so that pathway Decat too at about the + + + align:start position:0% +so that pathway Decat too at about the +same place the medal oniscus deat okay + + align:start position:0% +same place the medal oniscus deat okay + + + align:start position:0% +same place the medal oniscus deat okay +at the CLE that's a very dramatic place + + align:start position:0% +at the CLE that's a very dramatic place + + + align:start position:0% +at the CLE that's a very dramatic place +in the brain between hind brain and + + align:start position:0% +in the brain between hind brain and + + + align:start position:0% +in the brain between hind brain and +spinal cord because of the major + + align:start position:0% +spinal cord because of the major + + + align:start position:0% +spinal cord because of the major +decussations that occur there just above + + align:start position:0% +decussations that occur there just above + + + align:start position:0% +decussations that occur there just above +the dorsal column that + + align:start position:0% +the dorsal column that + + + align:start position:0% +the dorsal column that +the all right and I mentioned birds have + + align:start position:0% +the all right and I mentioned birds have + + + align:start position:0% +the all right and I mentioned birds have +this too uh you have a structure in + + align:start position:0% +this too uh you have a structure in + + + align:start position:0% +this too uh you have a structure in +Birds particularly prominent in the more + + align:start position:0% +Birds particularly prominent in the more + + + align:start position:0% +Birds particularly prominent in the more +advanced + + align:start position:0% +advanced + + + align:start position:0% +advanced +Birds + + align:start position:0% +Birds + + + align:start position:0% +Birds +uh like owls and other Raptors uh but + + align:start position:0% +uh like owls and other Raptors uh but + + + align:start position:0% +uh like owls and other Raptors uh but +many birds have this it's a the word + + align:start position:0% +many birds have this it's a the word + + + align:start position:0% +many birds have this it's a the word +word Vol in German means a bulge and it + + align:start position:0% +word Vol in German means a bulge and it + + + align:start position:0% +word Vol in German means a bulge and it +does form a bulge in the hemispheres of + + align:start position:0% +does form a bulge in the hemispheres of + + + align:start position:0% +does form a bulge in the hemispheres of +these animals and they have a motor + + align:start position:0% +these animals and they have a motor + + + align:start position:0% +these animals and they have a motor +wolst just like our motor cortex IT + + align:start position:0% +wolst just like our motor cortex IT + + + align:start position:0% +wolst just like our motor cortex IT +projects directly to the spinal cord + + align:start position:0% +projects directly to the spinal cord + + + align:start position:0% +projects directly to the spinal cord +they do have some met sensory wolst and + + align:start position:0% +they do have some met sensory wolst and + + + align:start position:0% +they do have some met sensory wolst and +visual wolst as + + align:start position:0% +visual wolst as + + + align:start position:0% +visual wolst as +well they also have a very large + + align:start position:0% +well they also have a very large + + + align:start position:0% +well they also have a very large +subcortical region that has connections + + align:start position:0% +subcortical region that has connections + + + align:start position:0% +subcortical region that has connections +also like neocortex Just Like the Wolf + + align:start position:0% +also like neocortex Just Like the Wolf + + + align:start position:0% +also like neocortex Just Like the Wolf +does but it doesn't look like CeX at all + + align:start position:0% +does but it doesn't look like CeX at all + + + align:start position:0% +does but it doesn't look like CeX at all +it's actually + + align:start position:0% + + + + align:start position:0% + +subcortical okay it's called the nested + + align:start position:0% +subcortical okay it's called the nested + + + align:start position:0% +subcortical okay it's called the nested +pallum or the Nido pallion + + align:start position:0% +pallum or the Nido pallion + + + align:start position:0% +pallum or the Nido pallion +we'll mention that a few times just so + + align:start position:0% +we'll mention that a few times just so + + + align:start position:0% +we'll mention that a few times just so +you know something about our + + align:start position:0% +you know something about our + + + align:start position:0% +you know something about our +other companions it's Advanced + + align:start position:0% +other companions it's Advanced + + + align:start position:0% +other companions it's Advanced +vertebrates all + + align:start position:0% +vertebrates all + + + align:start position:0% +vertebrates all +right now let's just mention very brief + + align:start position:0% +right now let's just mention very brief + + + align:start position:0% +right now let's just mention very brief +briefly what characterizes the sensory + + align:start position:0% +briefly what characterizes the sensory + + + align:start position:0% +briefly what characterizes the sensory +and motor functions of the + + align:start position:0% +and motor functions of the + + + align:start position:0% +and motor functions of the +neocortex and what other types of + + align:start position:0% +neocortex and what other types of + + + align:start position:0% +neocortex and what other types of +functions depend on + + align:start position:0% +functions depend on + + + align:start position:0% +functions depend on +neocortex think of neocortex as adding + + align:start position:0% +neocortex think of neocortex as adding + + + align:start position:0% +neocortex think of neocortex as adding +to S sensory + + align:start position:0% +to S sensory + + + align:start position:0% +to S sensory +processes + + align:start position:0% +processes + + + align:start position:0% +processes +Acuity both sensory and motor fine + + align:start position:0% +Acuity both sensory and motor fine + + + align:start position:0% +Acuity both sensory and motor fine +movement + + align:start position:0% +movement + + + align:start position:0% +movement +control fine discrimination of objects + + align:start position:0% +control fine discrimination of objects + + + align:start position:0% +control fine discrimination of objects +that also made better object P objects + + align:start position:0% +that also made better object P objects + + + align:start position:0% +that also made better object P objects +could be separated from the background + + align:start position:0% +could be separated from the background + + + align:start position:0% +could be separated from the background +more easily so it's not just a m mish + + align:start position:0% +more easily so it's not just a m mish + + + align:start position:0% +more easily so it's not just a m mish +mash of stimuli they're responding to + + align:start position:0% +mash of stimuli they're responding to + + + align:start position:0% +mash of stimuli they're responding to +but they respond to specific objects so + + align:start position:0% +but they respond to specific objects so + + + align:start position:0% +but they respond to specific objects so +that means they have to form images of + + align:start position:0% +that means they have to form images of + + + align:start position:0% +that means they have to form images of +those objects and that's something NE + + align:start position:0% +those objects and that's something NE + + + align:start position:0% +those objects and that's something NE +cortex + + align:start position:0% +cortex + + + align:start position:0% +cortex +does and I think the most unique thing + + align:start position:0% +does and I think the most unique thing + + + align:start position:0% +does and I think the most unique thing +about + + align:start position:0% +about + + + align:start position:0% +about +neocortex you know just that fine + + align:start position:0% +neocortex you know just that fine + + + align:start position:0% +neocortex you know just that fine +control the Acuity sensory and motor + + align:start position:0% +control the Acuity sensory and motor + + + align:start position:0% +control the Acuity sensory and motor +that's just sort of a quantitative + + align:start position:0% +that's just sort of a quantitative + + + align:start position:0% +that's just sort of a quantitative +improvement over what lower structures + + align:start position:0% +improvement over what lower structures + + + align:start position:0% +improvement over what lower structures +did but this is something really unique + + align:start position:0% +did but this is something really unique + + + align:start position:0% +did but this is something really unique +it in it adds the ability to anticipate + + align:start position:0% +it in it adds the ability to anticipate + + + align:start position:0% +it in it adds the ability to anticipate +and plan anticipate stimuli we do that + + align:start position:0% +and plan anticipate stimuli we do that + + + align:start position:0% +and plan anticipate stimuli we do that +through image + + align:start position:0% +through image + + + align:start position:0% +through image +formation Imaging depends on the + + align:start position:0% +formation Imaging depends on the + + + align:start position:0% +formation Imaging depends on the +posterior parts of the ne cortex and + + align:start position:0% +posterior parts of the ne cortex and + + + align:start position:0% +posterior parts of the ne cortex and +also we plan movements we don't just + + align:start position:0% +also we plan movements we don't just + + + align:start position:0% +also we plan movements we don't just +react uh that uses an internal model a + + align:start position:0% +react uh that uses an internal model a + + + align:start position:0% +react uh that uses an internal model a +kind of simulation of the world depends + + align:start position:0% +kind of simulation of the world depends + + + align:start position:0% +kind of simulation of the world depends +on those images as well so those are + + align:start position:0% +on those images as well so those are + + + align:start position:0% +on those images as well so those are +really the unique parts and I put review + + align:start position:0% +really the unique parts and I put review + + + align:start position:0% +really the unique parts and I put review +slides at the end of this chapter that + + align:start position:0% +slides at the end of this chapter that + + + align:start position:0% +slides at the end of this chapter that +you should look + + align:start position:0% +you should look + + + align:start position:0% +you should look +at because I want to get on here + + align:start position:0% + + + + align:start position:0% + +with the main topic of the day formation + + align:start position:0% +with the main topic of the day formation + + + align:start position:0% +with the main topic of the day formation +the neural tube in the embryo how + + align:start position:0% +the neural tube in the embryo how + + + align:start position:0% +the neural tube in the embryo how +central nervous system develop be + + align:start position:0% +central nervous system develop be + + + align:start position:0% +central nervous system develop be +development begins and we'll focus on + + align:start position:0% +development begins and we'll focus on + + + align:start position:0% +development begins and we'll focus on +the spinal level but that is where the + + align:start position:0% +the spinal level but that is where the + + + align:start position:0% +the spinal level but that is where the +neural tube first fully forms but the + + align:start position:0% +neural tube first fully forms but the + + + align:start position:0% +neural tube first fully forms but the +entire central nervous system begins as + + align:start position:0% +entire central nervous system begins as + + + align:start position:0% +entire central nervous system begins as +a tube all right + + align:start position:0% + + + + align:start position:0% + +remember it all evolves actually + + align:start position:0% +remember it all evolves actually + + + align:start position:0% +remember it all evolves actually +together we + + align:start position:0% +together we + + + align:start position:0% +together we +saw so we're going to do the embryology + + align:start position:0% +saw so we're going to do the embryology + + + align:start position:0% +saw so we're going to do the embryology +today and then next time we'll be able + + align:start position:0% +today and then next time we'll be able + + + align:start position:0% +today and then next time we'll be able +to get to the adult spinal cord and also + + align:start position:0% +to get to the adult spinal cord and also + + + align:start position:0% +to get to the adult spinal cord and also +the autonomic nervous + + align:start position:0% +the autonomic nervous + + + align:start position:0% +the autonomic nervous +system these are the stages of + + align:start position:0% +system these are the stages of + + + align:start position:0% +system these are the stages of +development of a nervous system after + + align:start position:0% +development of a nervous system after + + + align:start position:0% +development of a nervous system after +the egg is + + align:start position:0% +the egg is + + + align:start position:0% +the egg is +fertilized you get the formation of a + + align:start position:0% +fertilized you get the formation of a + + + align:start position:0% +fertilized you get the formation of a +mora a clump of cells that becomes a + + align:start position:0% +mora a clump of cells that becomes a + + + align:start position:0% +mora a clump of cells that becomes a +blastula which is a hollow ball of cells + + align:start position:0% +blastula which is a hollow ball of cells + + + align:start position:0% +blastula which is a hollow ball of cells +but now it's got fluid in the middle + + align:start position:0% +but now it's got fluid in the middle + + + align:start position:0% +but now it's got fluid in the middle +then a major step + + align:start position:0% +then a major step + + + align:start position:0% +then a major step +gastrulation where the organism instead + + align:start position:0% +gastrulation where the organism instead + + + align:start position:0% +gastrulation where the organism instead +of just this hollow ball of cells the + + align:start position:0% +of just this hollow ball of cells the + + + align:start position:0% +of just this hollow ball of cells the +fluid in the middle becomes shaped like + + align:start position:0% +fluid in the middle becomes shaped like + + + align:start position:0% +fluid in the middle becomes shaped like +a dut formation of the elementary Canal + + align:start position:0% +a dut formation of the elementary Canal + + + align:start position:0% +a dut formation of the elementary Canal +mouth at one and anus at the other that + + align:start position:0% +mouth at one and anus at the other that + + + align:start position:0% +mouth at one and anus at the other that +forms very early you'll see pictures of + + align:start position:0% +forms very early you'll see pictures of + + + align:start position:0% +forms very early you'll see pictures of +that and then finally neurulation + + align:start position:0% +that and then finally neurulation + + + align:start position:0% +that and then finally neurulation +formation of a nervous system the major + + align:start position:0% +formation of a nervous system the major + + + align:start position:0% +formation of a nervous system the major +thing we want to talk + + align:start position:0% +thing we want to talk + + + align:start position:0% +thing we want to talk +about now LS walper in this very + + align:start position:0% +about now LS walper in this very + + + align:start position:0% +about now LS walper in this very +interesting little book Triumph of the + + align:start position:0% +interesting little book Triumph of the + + + align:start position:0% +interesting little book Triumph of the +embryo when he revised it other authors + + align:start position:0% +embryo when he revised it other authors + + + align:start position:0% +embryo when he revised it other authors +join other authors joined him and it + + align:start position:0% +join other authors joined him and it + + + align:start position:0% +join other authors joined him and it +became a more standard embryology + + align:start position:0% +became a more standard embryology + + + align:start position:0% +became a more standard embryology +book uh which is also very interesting + + align:start position:0% +book uh which is also very interesting + + + align:start position:0% +book uh which is also very interesting +all the things that I found in Triumph + + align:start position:0% +all the things that I found in Triumph + + + align:start position:0% +all the things that I found in Triumph +of the embryo is still there but he + + align:start position:0% +of the embryo is still there but he + + + align:start position:0% +of the embryo is still there but he +really simplified it and talked about + + align:start position:0% +really simplified it and talked about + + + align:start position:0% +really simplified it and talked about +the major principles and one of the + + align:start position:0% +the major principles and one of the + + + align:start position:0% +the major principles and one of the +things he laid out was the cellular + + align:start position:0% +things he laid out was the cellular + + + align:start position:0% +things he laid out was the cellular +events what are the cellular events that + + align:start position:0% +events what are the cellular events that + + + align:start position:0% +events what are the cellular events that +characterize development of the nervous + + align:start position:0% +characterize development of the nervous + + + align:start position:0% +characterize development of the nervous +system what are + + align:start position:0% + + + + align:start position:0% + +they well contraction parts of the cell + + align:start position:0% +they well contraction parts of the cell + + + align:start position:0% +they well contraction parts of the cell +could contract what does that involve it + + align:start position:0% +could contract what does that involve it + + + align:start position:0% +could contract what does that involve it +involves contractable proteins just like + + align:start position:0% +involves contractable proteins just like + + + align:start position:0% +involves contractable proteins just like +we have in muscle okay but cells have + + align:start position:0% +we have in muscle okay but cells have + + + align:start position:0% +we have in muscle okay but cells have +that all cells have that to some degree + + align:start position:0% +that all cells have that to some degree + + + align:start position:0% +that all cells have that to some degree +in development okay + + align:start position:0% + + + + align:start position:0% + +contraction well cells have to in order + + align:start position:0% +contraction well cells have to in order + + + align:start position:0% +contraction well cells have to in order +to be to form organized tissue cells + + align:start position:0% +to be to form organized tissue cells + + + align:start position:0% +to be to form organized tissue cells +have to be able to stick to things stick + + align:start position:0% +have to be able to stick to things stick + + + align:start position:0% +have to be able to stick to things stick +to each other uh they form these little + + align:start position:0% +to each other uh they form these little + + + align:start position:0% +to each other uh they form these little +processes that can adhere to something + + align:start position:0% +processes that can adhere to something + + + align:start position:0% +processes that can adhere to something +so they show adhesion and that adhes the + + align:start position:0% +so they show adhesion and that adhes the + + + align:start position:0% +so they show adhesion and that adhes the +adhesive properties through cell + + align:start position:0% +adhesive properties through cell + + + align:start position:0% +adhesive properties through cell +adhesion molecules in the membrane which + + align:start position:0% +adhesion molecules in the membrane which + + + align:start position:0% +adhesion molecules in the membrane which +can change during the course of + + align:start position:0% +can change during the course of + + + align:start position:0% +can change during the course of +development uh that's a a big part of + + align:start position:0% +development uh that's a a big part of + + + align:start position:0% +development uh that's a a big part of +development selective adhesion and + + align:start position:0% +development selective adhesion and + + + align:start position:0% +development selective adhesion and +changes in + + align:start position:0% +changes in + + + align:start position:0% +changes in +adhesion okay and then cells can move + + align:start position:0% +adhesion okay and then cells can move + + + align:start position:0% +adhesion okay and then cells can move +how do they move so we'll be talking + + align:start position:0% +how do they move so we'll be talking + + + align:start position:0% +how do they move so we'll be talking +about + + align:start position:0% +about + + + align:start position:0% +about +that and uh finally of course growth and + + align:start position:0% +that and uh finally of course growth and + + + align:start position:0% +that and uh finally of course growth and +by growth often an embryologist is + + align:start position:0% +by growth often an embryologist is + + + align:start position:0% +by growth often an embryologist is +talking about growth by proliferation of + + align:start position:0% +talking about growth by proliferation of + + + align:start position:0% +talking about growth by proliferation of +cells + + align:start position:0% +cells + + + align:start position:0% +cells +mitosis it also means growth increased + + align:start position:0% +mitosis it also means growth increased + + + align:start position:0% +mitosis it also means growth increased +size of cells but the main factor is + + align:start position:0% +size of cells but the main factor is + + + align:start position:0% +size of cells but the main factor is +increased numbers of cells + + align:start position:0% + + + + align:start position:0% + +okay so here's the pictures that walper + + align:start position:0% +okay so here's the pictures that walper + + + align:start position:0% +okay so here's the pictures that walper +uses from a single fertilized + + align:start position:0% +uses from a single fertilized + + + align:start position:0% +uses from a single fertilized +egg here to the Mora a clump of it looks + + align:start position:0% +egg here to the Mora a clump of it looks + + + align:start position:0% +egg here to the Mora a clump of it looks +like a raspberry and here it becomes the + + align:start position:0% +like a raspberry and here it becomes the + + + align:start position:0% +like a raspberry and here it becomes the +blastula fluid in the middle and then + + align:start position:0% +blastula fluid in the middle and then + + + align:start position:0% +blastula fluid in the middle and then +note some cells have moved to the + + align:start position:0% +note some cells have moved to the + + + align:start position:0% +note some cells have moved to the +interior and there's more contraction at + + align:start position:0% +interior and there's more contraction at + + + align:start position:0% +interior and there's more contraction at +one side + + align:start position:0% +one side + + + align:start position:0% +one side +the out the the outside of the cell then + + align:start position:0% +the out the the outside of the cell then + + + align:start position:0% +the out the the outside of the cell then +on the inside and that leads to an + + align:start position:0% +on the inside and that leads to an + + + align:start position:0% +on the inside and that leads to an +invagination as you see beginning here + + align:start position:0% +invagination as you see beginning here + + + align:start position:0% +invagination as you see beginning here +and then look what + + align:start position:0% +and then look what + + + align:start position:0% +and then look what +happens these little processes extend + + align:start position:0% +happens these little processes extend + + + align:start position:0% +happens these little processes extend +out those little filaments are called + + align:start position:0% +out those little filaments are called + + + align:start position:0% +out those little filaments are called +filopodia okay filamentous feet okay + + align:start position:0% +filopodia okay filamentous feet okay + + + align:start position:0% +filopodia okay filamentous feet okay +they extend out and they actually reach + + align:start position:0% +they extend out and they actually reach + + + align:start position:0% +they extend out and they actually reach +the other side where they adhere so now + + align:start position:0% +the other side where they adhere so now + + + align:start position:0% +the other side where they adhere so now +you have + + align:start position:0% +you have + + + align:start position:0% +you have +adhesion you have most of these + + align:start position:0% +adhesion you have most of these + + + align:start position:0% +adhesion you have most of these +processes we just talked about are + + align:start position:0% +processes we just talked about are + + + align:start position:0% +processes we just talked about are +happening + + align:start position:0% +happening + + + align:start position:0% +happening +contraction + + align:start position:0% +contraction + + + align:start position:0% +contraction +adhesion + + align:start position:0% +adhesion + + + align:start position:0% +adhesion +movement notice the movement that's + + align:start position:0% +movement notice the movement that's + + + align:start position:0% +movement notice the movement that's +being caused by the contraction + + align:start position:0% +being caused by the contraction + + + align:start position:0% +being caused by the contraction +contractable proteins in those filipodia + + align:start position:0% +contractable proteins in those filipodia + + + align:start position:0% +contractable proteins in those filipodia +so it + + align:start position:0% +so it + + + align:start position:0% +so it +pulls this side of the embryo right + + align:start position:0% +pulls this side of the embryo right + + + align:start position:0% +pulls this side of the embryo right +across and that causes changes that + + align:start position:0% +across and that causes changes that + + + align:start position:0% +across and that causes changes that +cause an opening to + + align:start position:0% +cause an opening to + + + align:start position:0% +cause an opening to +form between here and here the cells + + align:start position:0% +form between here and here the cells + + + align:start position:0% +form between here and here the cells +continue to move to the in inside but + + align:start position:0% +continue to move to the in inside but + + + align:start position:0% +continue to move to the in inside but +that + + align:start position:0% +that + + + align:start position:0% +that +process from here to here or actually + + align:start position:0% +process from here to here or actually + + + align:start position:0% +process from here to here or actually +all along the bottom is called + + align:start position:0% +all along the bottom is called + + + align:start position:0% +all along the bottom is called +gastrulation it's just seen in the + + align:start position:0% +gastrulation it's just seen in the + + + align:start position:0% +gastrulation it's just seen in the +sections okay this just shows us one of + + align:start position:0% +sections okay this just shows us one of + + + align:start position:0% +sections okay this just shows us one of +the cells that how complicated they can + + align:start position:0% +the cells that how complicated they can + + + align:start position:0% +the cells that how complicated they can +be with their various extensions and + + align:start position:0% +be with their various extensions and + + + align:start position:0% +be with their various extensions and +movement + + align:start position:0% +movement + + + align:start position:0% +movement +because if this was all there is we'd + + align:start position:0% +because if this was all there is we'd + + + align:start position:0% +because if this was all there is we'd +have one + + align:start position:0% +have one + + + align:start position:0% +have one +layer that outer layer is the ectoderm + + align:start position:0% +layer that outer layer is the ectoderm + + + align:start position:0% +layer that outer layer is the ectoderm +but cells move inward they move to the + + align:start position:0% +but cells move inward they move to the + + + align:start position:0% +but cells move inward they move to the +interior and that becomes the mism and + + align:start position:0% +interior and that becomes the mism and + + + align:start position:0% +interior and that becomes the mism and +the endoderm mism forming muscle and + + align:start position:0% +the endoderm mism forming muscle and + + + align:start position:0% +the endoderm mism forming muscle and +skeleton and the endoderm forming the + + align:start position:0% +skeleton and the endoderm forming the + + + align:start position:0% +skeleton and the endoderm forming the +internal organs + + align:start position:0% + + + + align:start position:0% + +okay so then we want to talk + + align:start position:0% +okay so then we want to talk + + + align:start position:0% +okay so then we want to talk +about that still doesn't none of this + + align:start position:0% +about that still doesn't none of this + + + align:start position:0% +about that still doesn't none of this +gives you a central nervous system okay + + align:start position:0% +gives you a central nervous system okay + + + align:start position:0% +gives you a central nervous system okay +how do we get a central nervous system + + align:start position:0% +how do we get a central nervous system + + + align:start position:0% +how do we get a central nervous system +out of + + align:start position:0% +out of + + + align:start position:0% +out of +that so we need to talk about neural + + align:start position:0% +that so we need to talk about neural + + + align:start position:0% +that so we need to talk about neural +with the formation of the neural tube + + align:start position:0% +with the formation of the neural tube + + + align:start position:0% +with the formation of the neural tube +and then proliferation of the cells + + align:start position:0% +and then proliferation of the cells + + + align:start position:0% +and then proliferation of the cells +migration of cells and differentiation + + align:start position:0% +migration of cells and differentiation + + + align:start position:0% +migration of cells and differentiation +of cells by differentiation we mean the + + align:start position:0% +of cells by differentiation we mean the + + + align:start position:0% +of cells by differentiation we mean the +cell changes so the cells look different + + align:start position:0% +cell changes so the cells look different + + + align:start position:0% +cell changes so the cells look different +from each other they differentiate from + + align:start position:0% +from each other they differentiate from + + + align:start position:0% +from each other they differentiate from +each other they form dendrites they form + + align:start position:0% +each other they form dendrites they form + + + align:start position:0% +each other they form dendrites they form +axons if they're + + align:start position:0% +axons if they're + + + align:start position:0% +axons if they're +neurons if they're gal cells they also + + align:start position:0% +neurons if they're gal cells they also + + + align:start position:0% +neurons if they're gal cells they also +form processes depending on what kind of + + align:start position:0% +form processes depending on what kind of + + + align:start position:0% +form processes depending on what kind of +Gia they are all + + align:start position:0% +Gia they are all + + + align:start position:0% +Gia they are all +right so these are the questions I'm + + align:start position:0% +right so these are the questions I'm + + + align:start position:0% +right so these are the questions I'm +asking first of all what is the not + + align:start position:0% +asking first of all what is the not + + + align:start position:0% +asking first of all what is the not +chord we heard that term used before you + + align:start position:0% +chord we heard that term used before you + + + align:start position:0% +chord we heard that term used before you +should remember what it + + align:start position:0% +should remember what it + + + align:start position:0% +should remember what it +is some of you might what is the not + + align:start position:0% +is some of you might what is the not + + + align:start position:0% +is some of you might what is the not +cord it's not in all + + align:start position:0% +cord it's not in all + + + align:start position:0% +cord it's not in all +animals it's just in all animals that we + + align:start position:0% +animals it's just in all animals that we + + + align:start position:0% +animals it's just in all animals that we +call + + align:start position:0% +call + + + align:start position:0% +call +cordat so what is it the + + align:start position:0% +cordat so what is it the + + + align:start position:0% +cordat so what is it the +Nord + + align:start position:0% + + + + align:start position:0% + +yes + + align:start position:0% + + + + align:start position:0% + +yeah it's it tube may not be the most + + align:start position:0% +yeah it's it tube may not be the most + + + align:start position:0% +yeah it's it tube may not be the most +accurate it's cartilaginous for sure uh + + align:start position:0% +accurate it's cartilaginous for sure uh + + + align:start position:0% +accurate it's cartilaginous for sure uh +where is + + align:start position:0% + + + + align:start position:0% + +it but wait it precedes the neural + + align:start position:0% +it but wait it precedes the neural + + + align:start position:0% +it but wait it precedes the neural +tool but it is a but where in the + + align:start position:0% +tool but it is a but where in the + + + align:start position:0% +tool but it is a but where in the +organism the what at least what does it + + align:start position:0% +organism the what at least what does it + + + align:start position:0% +organism the what at least what does it +become in the + + align:start position:0% + + + + align:start position:0% + +organism the back exactly it's always + + align:start position:0% +organism the back exactly it's always + + + align:start position:0% +organism the back exactly it's always +along the back okay or at least what's + + align:start position:0% +along the back okay or at least what's + + + align:start position:0% +along the back okay or at least what's +going to become the back it maybe that's + + align:start position:0% +going to become the back it maybe that's + + + align:start position:0% +going to become the back it maybe that's +how it becomes a back okay the not + + align:start position:0% +how it becomes a back okay the not + + + align:start position:0% +how it becomes a back okay the not +cordant is at the surface one side that + + align:start position:0% +cordant is at the surface one side that + + + align:start position:0% +cordant is at the surface one side that +becomes the back + + align:start position:0% + + + + align:start position:0% + +okay it doesn't become the backbone but + + align:start position:0% +okay it doesn't become the backbone but + + + align:start position:0% +okay it doesn't become the backbone but +the back the skeletal elements form + + align:start position:0% +the back the skeletal elements form + + + align:start position:0% +the back the skeletal elements form +around + + align:start position:0% +around + + + align:start position:0% +around +it okay there are induction processes + + align:start position:0% +it okay there are induction processes + + + align:start position:0% +it okay there are induction processes +molecules coming from the noord exert + + align:start position:0% +molecules coming from the noord exert + + + align:start position:0% +molecules coming from the noord exert +really powerful changes first of all in + + align:start position:0% +really powerful changes first of all in + + + align:start position:0% +really powerful changes first of all in +the formation of the nervous system then + + align:start position:0% +the formation of the nervous system then + + + align:start position:0% +the formation of the nervous system then +the formation of the skeleton as well + + align:start position:0% + + + + align:start position:0% + +okay who + + align:start position:0% +okay who + + + align:start position:0% +okay who +discovered this phenomenon of induction + + align:start position:0% +discovered this phenomenon of induction + + + align:start position:0% +discovered this phenomenon of induction +of the + + align:start position:0% +of the + + + align:start position:0% +of the +CNS now it we know now that the + + align:start position:0% +CNS now it we know now that the + + + align:start position:0% +CNS now it we know now that the +inductive process the not cord induces + + align:start position:0% +inductive process the not cord induces + + + align:start position:0% +inductive process the not cord induces +the formation of a nervous system but + + align:start position:0% +the formation of a nervous system but + + + align:start position:0% +the formation of a nervous system but +how did we how is it discovered who + + align:start position:0% +how did we how is it discovered who + + + align:start position:0% +how did we how is it discovered who +discovered it that that there's some + + align:start position:0% +discovered it that that there's some + + + align:start position:0% +discovered it that that there's some +kind of induction that's happening + + align:start position:0% +kind of induction that's happening + + + align:start position:0% +kind of induction that's happening +because if you move things around you + + align:start position:0% +because if you move things around you + + + align:start position:0% +because if you move things around you +can get nervous system farming + + align:start position:0% +can get nervous system farming + + + align:start position:0% +can get nervous system farming +differently or in different + + align:start position:0% +differently or in different + + + align:start position:0% +differently or in different +places you remember the names there were + + align:start position:0% +places you remember the names there were + + + align:start position:0% +places you remember the names there were +actually two people but only one of them + + align:start position:0% +actually two people but only one of them + + + align:start position:0% +actually two people but only one of them +got the Nobel Prize for + + align:start position:0% +got the Nobel Prize for + + + align:start position:0% +got the Nobel Prize for +it he's name was + + align:start position:0% +it he's name was + + + align:start position:0% +it he's name was +Hunan okay Shaman got the prize but the + + align:start position:0% +Hunan okay Shaman got the prize but the + + + align:start position:0% +Hunan okay Shaman got the prize but the +discovery was made made in his lab by a + + align:start position:0% +discovery was made made in his lab by a + + + align:start position:0% +discovery was made made in his lab by a +student young woman named Hilda + + align:start position:0% +student young woman named Hilda + + + align:start position:0% +student young woman named Hilda +Mangold + + align:start position:0% +Mangold + + + align:start position:0% +Mangold +okay why didn't she get The Nobel + + align:start position:0% +okay why didn't she get The Nobel + + + align:start position:0% +okay why didn't she get The Nobel +Prize Unfortunately they don't give + + align:start position:0% +Prize Unfortunately they don't give + + + align:start position:0% +Prize Unfortunately they don't give +Nobel prizes to someone who has + + align:start position:0% +Nobel prizes to someone who has + + + align:start position:0% +Nobel prizes to someone who has +died she died in the kitchen accident + + align:start position:0% +died she died in the kitchen accident + + + align:start position:0% +died she died in the kitchen accident +when she was only 26 years + + align:start position:0% +when she was only 26 years + + + align:start position:0% +when she was only 26 years +old but she should be remembered just as + + align:start position:0% +old but she should be remembered just as + + + align:start position:0% +old but she should be remembered just as +famon is for the discovery of induction + + align:start position:0% +famon is for the discovery of induction + + + align:start position:0% +famon is for the discovery of induction +of the nervous + + align:start position:0% + + + + align:start position:0% + +system and then we want to know what + + align:start position:0% +system and then we want to know what + + + align:start position:0% +system and then we want to know what +neuroc crest cells are You' got to know + + align:start position:0% +neuroc crest cells are You' got to know + + + align:start position:0% +neuroc crest cells are You' got to know +something about the neural tube + + align:start position:0% +something about the neural tube + + + align:start position:0% +something about the neural tube +formation to be able to answer that you + + align:start position:0% +formation to be able to answer that you + + + align:start position:0% +formation to be able to answer that you +can I should have a piece of paper here + + align:start position:0% +can I should have a piece of paper here + + + align:start position:0% +can I should have a piece of paper here +I didn't bring my piece of paper you + + align:start position:0% +I didn't bring my piece of paper you + + + align:start position:0% +I didn't bring my piece of paper you +just take a piece of paper and push it + + align:start position:0% +just take a piece of paper and push it + + + align:start position:0% +just take a piece of paper and push it +to two ends what happens it will indent + + align:start position:0% +to two ends what happens it will indent + + + align:start position:0% +to two ends what happens it will indent +right and you can get it to indent in + + align:start position:0% +right and you can get it to indent in + + + align:start position:0% +right and you can get it to indent in +one place that's what happens to the + + align:start position:0% +one place that's what happens to the + + + align:start position:0% +one place that's what happens to the +nervous system system here okay here + + align:start position:0% +nervous system system here okay here + + + align:start position:0% +nervous system system here okay here +here's the sheet of paper it's one cell + + align:start position:0% +here's the sheet of paper it's one cell + + + align:start position:0% +here's the sheet of paper it's one cell +thick uh + + align:start position:0% +thick uh + + + align:start position:0% +thick uh +ectoderm and that is the not + + align:start position:0% +ectoderm and that is the not + + + align:start position:0% +ectoderm and that is the not +cord this is just part of the ectoderm + + align:start position:0% +cord this is just part of the ectoderm + + + align:start position:0% +cord this is just part of the ectoderm +the part that will become the back of + + align:start position:0% +the part that will become the back of + + + align:start position:0% +the part that will become the back of +the + + align:start position:0% +the + + + align:start position:0% +the +organism okay there's the not cord then + + align:start position:0% +organism okay there's the not cord then + + + align:start position:0% +organism okay there's the not cord then +there's an influence from the not cord + + align:start position:0% +there's an influence from the not cord + + + align:start position:0% +there's an influence from the not cord +note here I show cells getting thicker + + align:start position:0% +note here I show cells getting thicker + + + align:start position:0% +note here I show cells getting thicker +in this region that's we call a neural + + align:start position:0% +in this region that's we call a neural + + + align:start position:0% +in this region that's we call a neural +plate + + align:start position:0% +plate + + + align:start position:0% +plate +the cells are already determined now + + align:start position:0% +the cells are already determined now + + + align:start position:0% +the cells are already determined now +which ones are going to become nervous + + align:start position:0% +which ones are going to become nervous + + + align:start position:0% +which ones are going to become nervous +system and which will + + align:start position:0% +system and which will + + + align:start position:0% +system and which will +remain other parts of the ectoderm like + + align:start position:0% +remain other parts of the ectoderm like + + + align:start position:0% +remain other parts of the ectoderm like +the skin primarily + + align:start position:0% +the skin primarily + + + align:start position:0% +the skin primarily +okay and then because of differences in + + align:start position:0% +okay and then because of differences in + + + align:start position:0% +okay and then because of differences in +contraction just like during + + align:start position:0% +contraction just like during + + + align:start position:0% +contraction just like during +gastrulation earlier you get an + + align:start position:0% + + + + align:start position:0% + +invagination so it doesn't really happen + + align:start position:0% +invagination so it doesn't really happen + + + align:start position:0% +invagination so it doesn't really happen +because somebody pushed the Sid + + align:start position:0% +because somebody pushed the Sid + + + align:start position:0% +because somebody pushed the Sid +like a piece of paper but the Dynamics + + align:start position:0% +like a piece of paper but the Dynamics + + + align:start position:0% +like a piece of paper but the Dynamics +are very similar so it starts to form a + + align:start position:0% +are very similar so it starts to form a + + + align:start position:0% +are very similar so it starts to form a +Groove along the back of the organism so + + align:start position:0% +Groove along the back of the organism so + + + align:start position:0% +Groove along the back of the organism so +think of it in three dimensions that's + + align:start position:0% +think of it in three dimensions that's + + + align:start position:0% +think of it in three dimensions that's +why I like you to think of a piece of + + align:start position:0% +why I like you to think of a piece of + + + align:start position:0% +why I like you to think of a piece of +paper if we push in it's going to form a + + align:start position:0% +paper if we push in it's going to form a + + + align:start position:0% +paper if we push in it's going to form a +big Groove all along the back of the + + align:start position:0% +big Groove all along the back of the + + + align:start position:0% +big Groove all along the back of the +organism there's the + + align:start position:0% +organism there's the + + + align:start position:0% +organism there's the +nort where molecules emanating from that + + align:start position:0% +nort where molecules emanating from that + + + align:start position:0% +nort where molecules emanating from that +noord are what's causing these changes + + align:start position:0% + + + + align:start position:0% + +in the ectoderm above it okay and North + + align:start position:0% +in the ectoderm above it okay and North + + + align:start position:0% +in the ectoderm above it okay and North +I hear I show two little bulges on the + + align:start position:0% +I hear I show two little bulges on the + + + align:start position:0% +I hear I show two little bulges on the +sides that is called the neural crest + + align:start position:0% +sides that is called the neural crest + + + align:start position:0% +sides that is called the neural crest +and it's very different because as these + + align:start position:0% +and it's very different because as these + + + align:start position:0% +and it's very different because as these +two edges come together so you end up + + align:start position:0% +two edges come together so you end up + + + align:start position:0% +two edges come together so you end up +with a tube these cells don't become + + align:start position:0% +with a tube these cells don't become + + + align:start position:0% +with a tube these cells don't become +part of the tube they stay on the + + align:start position:0% +part of the tube they stay on the + + + align:start position:0% +part of the tube they stay on the +outside it's those neural crust cells + + align:start position:0% +outside it's those neural crust cells + + + align:start position:0% +outside it's those neural crust cells +that form the peripheral nervous system + + align:start position:0% +that form the peripheral nervous system + + + align:start position:0% +that form the peripheral nervous system +all the cells of the peripheral nervous + + align:start position:0% +all the cells of the peripheral nervous + + + align:start position:0% +all the cells of the peripheral nervous +nous + + align:start position:0% +nous + + + align:start position:0% +nous +system come from the neural + + align:start position:0% +system come from the neural + + + align:start position:0% +system come from the neural +crest at this level of the nervous + + align:start position:0% +crest at this level of the nervous + + + align:start position:0% +crest at this level of the nervous +system now there are cells that don't + + align:start position:0% +system now there are cells that don't + + + align:start position:0% +system now there are cells that don't +come from neural crest in the head + + align:start position:0% +come from neural crest in the head + + + align:start position:0% +come from neural crest in the head +region there they come from both neural + + align:start position:0% +region there they come from both neural + + + align:start position:0% +region there they come from both neural +crest and from what we call plot just + + align:start position:0% +crest and from what we call plot just + + + align:start position:0% +crest and from what we call plot just +thickening of the ectoderm that happens + + align:start position:0% +thickening of the ectoderm that happens + + + align:start position:0% +thickening of the ectoderm that happens +due to other inductive + + align:start position:0% +due to other inductive + + + align:start position:0% +due to other inductive +influences okay not the noord now they + + align:start position:0% +influences okay not the noord now they + + + align:start position:0% +influences okay not the noord now they +can also for form periphal nervous + + align:start position:0% +can also for form periphal nervous + + + align:start position:0% +can also for form periphal nervous +system but here in the spinal cord + + align:start position:0% +system but here in the spinal cord + + + align:start position:0% +system but here in the spinal cord +all comes from the neural crest okay and + + align:start position:0% +all comes from the neural crest okay and + + + align:start position:0% +all comes from the neural crest okay and +then there's a few names you should + + align:start position:0% +then there's a few names you should + + + align:start position:0% +then there's a few names you should +learn when this tube + + align:start position:0% +learn when this tube + + + align:start position:0% +learn when this tube +forms note I show here the tube is + + align:start position:0% +forms note I show here the tube is + + + align:start position:0% +forms note I show here the tube is +already getting a little thicker + + align:start position:0% +already getting a little thicker + + + align:start position:0% +already getting a little thicker +there're cell proliferating there they + + align:start position:0% +there're cell proliferating there they + + + align:start position:0% +there're cell proliferating there they +proliferate in the sides of the tube not + + align:start position:0% +proliferate in the sides of the tube not + + + align:start position:0% +proliferate in the sides of the tube not +at the very top and the very bottom the + + align:start position:0% +at the very top and the very bottom the + + + align:start position:0% +at the very top and the very bottom the +very top is called the roof plate it + + align:start position:0% +very top is called the roof plate it + + + align:start position:0% +very top is called the roof plate it +remains one C thic and the bottom is the + + align:start position:0% +remains one C thic and the bottom is the + + + align:start position:0% +remains one C thic and the bottom is the +floor plate it also remains one cell + + align:start position:0% +floor plate it also remains one cell + + + align:start position:0% +floor plate it also remains one cell +thick right to the adult okay but the + + align:start position:0% +thick right to the adult okay but the + + + align:start position:0% +thick right to the adult okay but the +walls get thicker and thicker and in + + align:start position:0% +walls get thicker and thicker and in + + + align:start position:0% +walls get thicker and thicker and in +development the ventral part closest to + + align:start position:0% +development the ventral part closest to + + + align:start position:0% +development the ventral part closest to +the Nord tends to proliferate a little + + align:start position:0% +the Nord tends to proliferate a little + + + align:start position:0% +the Nord tends to proliferate a little +bit + + align:start position:0% +bit + + + align:start position:0% +bit +faster okay that's where all the motor + + align:start position:0% +faster okay that's where all the motor + + + align:start position:0% +faster okay that's where all the motor +neurons will form so we call the upper + + align:start position:0% +neurons will form so we call the upper + + + align:start position:0% +neurons will form so we call the upper +part here the AER plate and the lower + + align:start position:0% +part here the AER plate and the lower + + + align:start position:0% +part here the AER plate and the lower +part the basil plate and the little + + align:start position:0% +part the basil plate and the little + + + align:start position:0% +part the basil plate and the little +Groove separating the two + + align:start position:0% +Groove separating the two + + + align:start position:0% +Groove separating the two +it's called the sulcus limitans the + + align:start position:0% +it's called the sulcus limitans the + + + align:start position:0% +it's called the sulcus limitans the +limiting sulcus you'll see pictures of + + align:start position:0% +limiting sulcus you'll see pictures of + + + align:start position:0% +limiting sulcus you'll see pictures of +that as we go + + align:start position:0% +that as we go + + + align:start position:0% +that as we go +on + + align:start position:0% +on + + + align:start position:0% +on +okay so let's + + align:start position:0% +okay so let's + + + align:start position:0% +okay so let's +take let's see do I have well we'll get + + align:start position:0% +take let's see do I have well we'll get + + + align:start position:0% +take let's see do I have well we'll get +to that I'm going to show you some + + align:start position:0% +to that I'm going to show you some + + + align:start position:0% +to that I'm going to show you some +pictures of it uh we mentioned this + + align:start position:0% +pictures of it uh we mentioned this + + + align:start position:0% +pictures of it uh we mentioned this +story already the discovery of induction + + align:start position:0% +story already the discovery of induction + + + align:start position:0% +story already the discovery of induction +where does that closure begin remember + + align:start position:0% +where does that closure begin remember + + + align:start position:0% +where does that closure begin remember +it's a group it's a neural group all + + align:start position:0% +it's a group it's a neural group all + + + align:start position:0% +it's a group it's a neural group all +along the back of the organism and then + + align:start position:0% +along the back of the organism and then + + + align:start position:0% +along the back of the organism and then +it + + align:start position:0% +it + + + align:start position:0% +it +uh it forms a tube in as you see in this + + align:start position:0% +uh it forms a tube in as you see in this + + + align:start position:0% +uh it forms a tube in as you see in this +picture okay well where does that where + + align:start position:0% +picture okay well where does that where + + + align:start position:0% +picture okay well where does that where +does this first + + align:start position:0% + + + + align:start position:0% + +begin here so I show you this + + align:start position:0% +begin here so I show you this + + + align:start position:0% +begin here so I show you this +picture it begins sort of in the middle + + align:start position:0% +picture it begins sort of in the middle + + + align:start position:0% +picture it begins sort of in the middle +so this is the head this is rostral this + + align:start position:0% +so this is the head this is rostral this + + + align:start position:0% +so this is the head this is rostral this +is the CLE end here that's where the + + align:start position:0% +is the CLE end here that's where the + + + align:start position:0% +is the CLE end here that's where the +neural tube is first closing so if we go + + align:start position:0% +neural tube is first closing so if we go + + + align:start position:0% +neural tube is first closing so if we go +further back or further forward it would + + align:start position:0% +further back or further forward it would + + + align:start position:0% +further back or further forward it would +look like this it would be a neural + + align:start position:0% +look like this it would be a neural + + + align:start position:0% +look like this it would be a neural +group still okay so it starts to close + + align:start position:0% +group still okay so it starts to close + + + align:start position:0% +group still okay so it starts to close +that region corresponds to the cervical + + align:start position:0% +that region corresponds to the cervical + + + align:start position:0% +that region corresponds to the cervical +region of the spinal cord the upper part + + align:start position:0% +region of the spinal cord the upper part + + + align:start position:0% +region of the spinal cord the upper part +or the most rostal part of the spinal + + align:start position:0% +or the most rostal part of the spinal + + + align:start position:0% +or the most rostal part of the spinal +cord that's where development is a + + align:start position:0% +cord that's where development is a + + + align:start position:0% +cord that's where development is a +little more advanced that's where the + + align:start position:0% +little more advanced that's where the + + + align:start position:0% +little more advanced that's where the +neural treat first + + align:start position:0% +neural treat first + + + align:start position:0% +neural treat first +closes + + align:start position:0% +closes + + + align:start position:0% +closes +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so the last regions to close as you can + + align:start position:0% +so the last regions to close as you can + + + align:start position:0% +so the last regions to close as you can +guess it sort of zips up this way and + + align:start position:0% +guess it sort of zips up this way and + + + align:start position:0% +guess it sort of zips up this way and +zips up cloudly very tail region here + + align:start position:0% +zips up cloudly very tail region here + + + align:start position:0% +zips up cloudly very tail region here +the last part to close and + + align:start position:0% +the last part to close and + + + align:start position:0% +the last part to close and +similarly the furthest the most Ral part + + align:start position:0% +similarly the furthest the most Ral part + + + align:start position:0% +similarly the furthest the most Ral part +of the CNS the last part to close so if + + align:start position:0% +of the CNS the last part to close so if + + + align:start position:0% +of the CNS the last part to close so if +some abnormality occurs during early + + align:start position:0% +some abnormality occurs during early + + + align:start position:0% +some abnormality occurs during early +development and it does happen you can + + align:start position:0% +development and it does happen you can + + + align:start position:0% +development and it does happen you can +get a failure to completely close when + + align:start position:0% +get a failure to completely close when + + + align:start position:0% +get a failure to completely close when +it doesn't close + + align:start position:0% +it doesn't close + + + align:start position:0% +it doesn't close +codly here you get a condition known as + + align:start position:0% +codly here you get a condition known as + + + align:start position:0% +codly here you get a condition known as +spinabifida + + align:start position:0% +spinabifida + + + align:start position:0% +spinabifida +okay that can be corrected + + align:start position:0% +okay that can be corrected + + + align:start position:0% +okay that can be corrected +surgically but when it fails to close + + align:start position:0% + + + + align:start position:0% + +rostrally the there's a failure of the + + align:start position:0% +rostrally the there's a failure of the + + + align:start position:0% +rostrally the there's a failure of the +of the forbrain to + + align:start position:0% +of the forbrain to + + + align:start position:0% +of the forbrain to +develop you call it anany basically it + + align:start position:0% +develop you call it anany basically it + + + align:start position:0% +develop you call it anany basically it +means without a + + align:start position:0% +means without a + + + align:start position:0% +means without a +brain they do have some brain they have + + align:start position:0% +brain they do have some brain they have + + + align:start position:0% +brain they do have some brain they have +a brain stem + + align:start position:0% +a brain stem + + + align:start position:0% +a brain stem +and babies that are born that way don't + + align:start position:0% +and babies that are born that way don't + + + align:start position:0% +and babies that are born that way don't +live very long it's impossible to repair + + align:start position:0% +live very long it's impossible to repair + + + align:start position:0% +live very long it's impossible to repair +that uh they've been studied a little + + align:start position:0% +that uh they've been studied a little + + + align:start position:0% +that uh they've been studied a little +bit uh in their brief very brief lives + + align:start position:0% +bit uh in their brief very brief lives + + + align:start position:0% +bit uh in their brief very brief lives +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so let's take a look at that + + align:start position:0% +so let's take a look at that + + + align:start position:0% +so let's take a look at that +happening + + align:start position:0% + + + + align:start position:0% + +uh + + align:start position:0% + + + + align:start position:0% + +these are interesting animations that + + align:start position:0% +these are interesting animations that + + + align:start position:0% +these are interesting animations that +you can actually find on the web if you + + align:start position:0% +you can actually find on the web if you + + + align:start position:0% +you can actually find on the web if you +look at the cross-section up here don't + + align:start position:0% +look at the cross-section up here don't + + + align:start position:0% +look at the cross-section up here don't +take notes Now look up here look up + + align:start position:0% +take notes Now look up here look up + + + align:start position:0% +take notes Now look up here look up +here look at the screen are you're + + align:start position:0% +here look at the screen are you're + + + align:start position:0% +here look at the screen are you're +missing the main + + align:start position:0% + + + + align:start position:0% + +show you see the neural tube in the 3D + + align:start position:0% +show you see the neural tube in the 3D + + + align:start position:0% +show you see the neural tube in the 3D +picture there closing and you see what's + + align:start position:0% +picture there closing and you see what's + + + align:start position:0% +picture there closing and you see what's +happening up there + + align:start position:0% +happening up there + + + align:start position:0% +happening up there +the black dots are the neural crest + + align:start position:0% +the black dots are the neural crest + + + align:start position:0% +the black dots are the neural crest +cells that are staying in the outside + + align:start position:0% +cells that are staying in the outside + + + align:start position:0% +cells that are staying in the outside +they don't get + + align:start position:0% +they don't get + + + align:start position:0% +they don't get +Incorporated the tube closes without + + align:start position:0% +Incorporated the tube closes without + + + align:start position:0% +Incorporated the tube closes without +them the red is the mism okay mostly + + align:start position:0% +them the red is the mism okay mostly + + + align:start position:0% +them the red is the mism okay mostly +muscle tissue there and the vertebrae + + align:start position:0% +muscle tissue there and the vertebrae + + + align:start position:0% +muscle tissue there and the vertebrae +are farming around the around the neural + + align:start position:0% +are farming around the around the neural + + + align:start position:0% +are farming around the around the neural +tube okay so now what are there that's + + align:start position:0% +tube okay so now what are there that's + + + align:start position:0% +tube okay so now what are there that's +where you find the pereral ganglia of + + align:start position:0% +where you find the pereral ganglia of + + + align:start position:0% +where you find the pereral ganglia of +the sympathetic nervous system and + + align:start position:0% +the sympathetic nervous system and + + + align:start position:0% +the sympathetic nervous system and +there's the dorsal root ganglia okay + + align:start position:0% +there's the dorsal root ganglia okay + + + align:start position:0% +there's the dorsal root ganglia okay +what are these out here there other + + align:start position:0% +what are these out here there other + + + align:start position:0% +what are these out here there other +neural crust cells I didn't mention + + align:start position:0% +neural crust cells I didn't mention + + + align:start position:0% +neural crust cells I didn't mention +those + + align:start position:0% +those + + + align:start position:0% +those +before they're migrating into the skin + + align:start position:0% +before they're migrating into the skin + + + align:start position:0% +before they're migrating into the skin +mostly + + align:start position:0% +mostly + + + align:start position:0% +mostly +melanoides the pigmented cells in the + + align:start position:0% +melanoides the pigmented cells in the + + + align:start position:0% +melanoides the pigmented cells in the +skin all + + align:start position:0% +skin all + + + align:start position:0% +skin all +right + + align:start position:0% +right + + + align:start position:0% +right +and rather than look at that again I + + align:start position:0% +and rather than look at that again I + + + align:start position:0% +and rather than look at that again I +want to show you an actual ual + + align:start position:0% +want to show you an actual ual + + + align:start position:0% +want to show you an actual ual +photograph of neurulation in the quad + + align:start position:0% +photograph of neurulation in the quad + + + align:start position:0% +photograph of neurulation in the quad +crog the + + align:start position:0% +crog the + + + align:start position:0% +crog the +zenopus okay it happens very fast here + + align:start position:0% +zenopus okay it happens very fast here + + + align:start position:0% +zenopus okay it happens very fast here +so we'll look at it several times if you + + align:start position:0% +so we'll look at it several times if you + + + align:start position:0% +so we'll look at it several times if you +just focus on one of + + align:start position:0% + + + + align:start position:0% + +these you see the whole thing because + + align:start position:0% +these you see the whole thing because + + + align:start position:0% +these you see the whole thing because +they've speeded it up so much with the + + align:start position:0% +they've speeded it up so much with the + + + align:start position:0% +they've speeded it up so much with the +formation you don't really see the + + align:start position:0% +formation you don't really see the + + + align:start position:0% +formation you don't really see the +neural plate but you see the neural + + align:start position:0% +neural plate but you see the neural + + + align:start position:0% +neural plate but you see the neural +Groove for me and you see it close uh + + align:start position:0% +Groove for me and you see it close uh + + + align:start position:0% +Groove for me and you see it close uh +zips + + align:start position:0% +zips + + + align:start position:0% +zips +up rostrally and codly and then the + + align:start position:0% +up rostrally and codly and then the + + + align:start position:0% +up rostrally and codly and then the +embryo turns a little bit so it looks + + align:start position:0% +embryo turns a little bit so it looks + + + align:start position:0% +embryo turns a little bit so it looks +more like the end of this + + align:start position:0% +more like the end of this + + + align:start position:0% +more like the end of this +one all + + align:start position:0% + + + + align:start position:0% + +right you can find those if you do some + + align:start position:0% +right you can find those if you do some + + + align:start position:0% +right you can find those if you do some +searching you can find them + + align:start position:0% +searching you can find them + + + align:start position:0% +searching you can find them +online this is just a picture of that + + align:start position:0% +online this is just a picture of that + + + align:start position:0% +online this is just a picture of that +early stage done with taken with the + + align:start position:0% +early stage done with taken with the + + + align:start position:0% +early stage done with taken with the +electron microscope when they've used a + + align:start position:0% +electron microscope when they've used a + + + align:start position:0% +electron microscope when they've used a +a method called Freeze fracture they + + align:start position:0% +a method called Freeze fracture they + + + align:start position:0% +a method called Freeze fracture they +freeze it solid then if they could get + + align:start position:0% +freeze it solid then if they could get + + + align:start position:0% +freeze it solid then if they could get +it to break along this line they will + + align:start position:0% +it to break along this line they will + + + align:start position:0% +it to break along this line they will +you can see individual + + align:start position:0% +you can see individual + + + align:start position:0% +you can see individual +cells uh in both the CNS there in the + + align:start position:0% +cells uh in both the CNS there in the + + + align:start position:0% +cells uh in both the CNS there in the +neural tube and the mism and the + + align:start position:0% +neural tube and the mism and the + + + align:start position:0% +neural tube and the mism and the +ectoderm and then you see the endoderm + + align:start position:0% +ectoderm and then you see the endoderm + + + align:start position:0% +ectoderm and then you see the endoderm +down here okay and this just shows what + + align:start position:0% +down here okay and this just shows what + + + align:start position:0% +down here okay and this just shows what +it's like in humans at particular stages + + align:start position:0% +it's like in humans at particular stages + + + align:start position:0% +it's like in humans at particular stages +22 and 24 + + align:start position:0% +22 and 24 + + + align:start position:0% +22 and 24 +days after + + align:start position:0% +days after + + + align:start position:0% +days after +conception uh + + align:start position:0% +conception uh + + + align:start position:0% +conception uh +this is I pick this because it's right + + align:start position:0% +this is I pick this because it's right + + + align:start position:0% +this is I pick this because it's right +after the neural tube starts to close in + + align:start position:0% +after the neural tube starts to close in + + + align:start position:0% +after the neural tube starts to close in +a hamster that I've used this it's it + + align:start position:0% +a hamster that I've used this it's it + + + align:start position:0% +a hamster that I've used this it's it +closes on the eighth day after + + align:start position:0% +closes on the eighth day after + + + align:start position:0% +closes on the eighth day after +conception so it can happen in some + + align:start position:0% +conception so it can happen in some + + + align:start position:0% +conception so it can happen in some +species very very fast of course they're + + align:start position:0% +species very very fast of course they're + + + align:start position:0% +species very very fast of course they're +much smaller Too + + align:start position:0% +much smaller Too + + + align:start position:0% +much smaller Too +Human tends to be slower in the larger + + align:start position:0% +Human tends to be slower in the larger + + + align:start position:0% +Human tends to be slower in the larger +animals + + align:start position:0% + + + + align:start position:0% + +okay so what is this term Sonic Hedgehog + + align:start position:0% +okay so what is this term Sonic Hedgehog + + + align:start position:0% +okay so what is this term Sonic Hedgehog +we're not going back to comparative + + align:start position:0% +we're not going back to comparative + + + align:start position:0% +we're not going back to comparative +neurology here it's the name for + + align:start position:0% +neurology here it's the name for + + + align:start position:0% +neurology here it's the name for +what + + align:start position:0% + + + + align:start position:0% + +sorry it's a it's a + + align:start position:0% +sorry it's a it's a + + + align:start position:0% +sorry it's a it's a +particular + + align:start position:0% +particular + + + align:start position:0% +particular +molecule Sonic Hedgehog it's just the + + align:start position:0% +molecule Sonic Hedgehog it's just the + + + align:start position:0% +molecule Sonic Hedgehog it's just the +name for a + + align:start position:0% +name for a + + + align:start position:0% +name for a +protein okay a molecule but where do + + align:start position:0% +protein okay a molecule but where do + + + align:start position:0% +protein okay a molecule but where do +Sonic Hedgehog it actually has a number + + align:start position:0% +Sonic Hedgehog it actually has a number + + + align:start position:0% +Sonic Hedgehog it actually has a number +of roles in the formation of nervous + + align:start position:0% +of roles in the formation of nervous + + + align:start position:0% +of roles in the formation of nervous +system where does it come from + + align:start position:0% +system where does it come from + + + align:start position:0% +system where does it come from +in this process we're studying right + + align:start position:0% +in this process we're studying right + + + align:start position:0% +in this process we're studying right +now I told you before where the + + align:start position:0% +now I told you before where the + + + align:start position:0% +now I told you before where the +induction comes + + align:start position:0% + + + + align:start position:0% + +from the notor Sonic Hedgehog is + + align:start position:0% +from the notor Sonic Hedgehog is + + + align:start position:0% +from the notor Sonic Hedgehog is +generated by the + + align:start position:0% +generated by the + + + align:start position:0% +generated by the +notocord it's induces the formation of + + align:start position:0% +notocord it's induces the formation of + + + align:start position:0% +notocord it's induces the formation of +the nervous system and does other things + + align:start position:0% +the nervous system and does other things + + + align:start position:0% +the nervous system and does other things +too and uh if we look at this + + align:start position:0% +too and uh if we look at this + + + align:start position:0% +too and uh if we look at this +picture they're + + align:start position:0% + + + + align:start position:0% + +coming these would be where the + + align:start position:0% +coming these would be where the + + + align:start position:0% +coming these would be where the +molecules are of course they're probably + + align:start position:0% +molecules are of course they're probably + + + align:start position:0% +molecules are of course they're probably +going all around I'm showing the ones + + align:start position:0% +going all around I'm showing the ones + + + align:start position:0% +going all around I'm showing the ones +that + + align:start position:0% +that + + + align:start position:0% +that +are are in a concentrated way are + + align:start position:0% +are are in a concentrated way are + + + align:start position:0% +are are in a concentrated way are +affecting these cells above it it's + + align:start position:0% +affecting these cells above it it's + + + align:start position:0% +affecting these cells above it it's +still coming there and it's affecting + + align:start position:0% +still coming there and it's affecting + + + align:start position:0% +still coming there and it's affecting +this lower part of the cord it serves as + + align:start position:0% +this lower part of the cord it serves as + + + align:start position:0% +this lower part of the cord it serves as +a ventralizing influence it makes that + + align:start position:0% +a ventralizing influence it makes that + + + align:start position:0% +a ventralizing influence it makes that +ventral part + + align:start position:0% +ventral part + + + align:start position:0% +ventral part +of the neural tube see they're still + + align:start position:0% +of the neural tube see they're still + + + align:start position:0% +of the neural tube see they're still +here it makes the cells here form + + align:start position:0% +here it makes the cells here form + + + align:start position:0% +here it makes the cells here form +differently than the cells up + + align:start position:0% +differently than the cells up + + + align:start position:0% +differently than the cells up +here without Sonic Hedgehog and its + + align:start position:0% +here without Sonic Hedgehog and its + + + align:start position:0% +here without Sonic Hedgehog and its +ventralizing influence you wouldn't get + + align:start position:0% +ventralizing influence you wouldn't get + + + align:start position:0% +ventralizing influence you wouldn't get +the form early differentiation of motor + + align:start position:0% +the form early differentiation of motor + + + align:start position:0% +the form early differentiation of motor +neurons okay what about the dorsal + + align:start position:0% +neurons okay what about the dorsal + + + align:start position:0% +neurons okay what about the dorsal +part there are induction inductive + + align:start position:0% +part there are induction inductive + + + align:start position:0% +part there are induction inductive +influences on this part the part that + + align:start position:0% +influences on this part the part that + + + align:start position:0% +influences on this part the part that +came from way out here forms the dorsal + + align:start position:0% +came from way out here forms the dorsal + + + align:start position:0% +came from way out here forms the dorsal +part of the + + align:start position:0% +part of the + + + align:start position:0% +part of the +cord those inductive influences came + + align:start position:0% +cord those inductive influences came + + + align:start position:0% +cord those inductive influences came +from the + + align:start position:0% +from the + + + align:start position:0% +from the +ectoderm okay and I mention it here the + + align:start position:0% +ectoderm okay and I mention it here the + + + align:start position:0% +ectoderm okay and I mention it here the +dorsalizing factors are secreted by the + + align:start position:0% +dorsalizing factors are secreted by the + + + align:start position:0% +dorsalizing factors are secreted by the +ectoderm Adent adjacent to the neural + + align:start position:0% +ectoderm Adent adjacent to the neural + + + align:start position:0% +ectoderm Adent adjacent to the neural +tube the main ones are this uh BMP four + + align:start position:0% +tube the main ones are this uh BMP four + + + align:start position:0% +tube the main ones are this uh BMP four +and seven BMP actually means bone + + align:start position:0% +and seven BMP actually means bone + + + align:start position:0% +and seven BMP actually means bone +morphogenetic protein because it has a + + align:start position:0% +morphogenetic protein because it has a + + + align:start position:0% +morphogenetic protein because it has a +role in B bone formation as well but now + + align:start position:0% +role in B bone formation as well but now + + + align:start position:0% +role in B bone formation as well but now +we're talking about its influence on the + + align:start position:0% +we're talking about its influence on the + + + align:start position:0% +we're talking about its influence on the +nervous system so it induces changes in + + align:start position:0% +nervous system so it induces changes in + + + align:start position:0% +nervous system so it induces changes in +the dorsal part of the + + align:start position:0% +the dorsal part of the + + + align:start position:0% +the dorsal part of the +cord okay that has causes those cells to + + align:start position:0% +cord okay that has causes those cells to + + + align:start position:0% +cord okay that has causes those cells to +develop differently than the ones + + align:start position:0% +develop differently than the ones + + + align:start position:0% +develop differently than the ones +eventually that leaves a lot of things + + align:start position:0% +eventually that leaves a lot of things + + + align:start position:0% +eventually that leaves a lot of things +unexplained but at least it was a start + + align:start position:0% +unexplained but at least it was a start + + + align:start position:0% +unexplained but at least it was a start +in looking at how the nervous system + + align:start position:0% +in looking at how the nervous system + + + align:start position:0% +in looking at how the nervous system +develops so now I want to talk about + + align:start position:0% +develops so now I want to talk about + + + align:start position:0% +develops so now I want to talk about +cell division what are the two main + + align:start position:0% +cell division what are the two main + + + align:start position:0% +cell division what are the two main +types of cell division that I describe + + align:start position:0% +types of cell division that I describe + + + align:start position:0% +types of cell division that I describe +in this + + align:start position:0% + + + + align:start position:0% + +chapter there are differences in cell + + align:start position:0% +chapter there are differences in cell + + + align:start position:0% +chapter there are differences in cell +division that make a huge difference in + + align:start position:0% +division that make a huge difference in + + + align:start position:0% +division that make a huge difference in +how the nervous system + + align:start position:0% +how the nervous system + + + align:start position:0% +how the nervous system +forms symmetric and asymmetric and for + + align:start position:0% +forms symmetric and asymmetric and for + + + align:start position:0% +forms symmetric and asymmetric and for +that we need to look at a picture like + + align:start position:0% +that we need to look at a picture like + + + align:start position:0% +that we need to look at a picture like +this this is the cell + + align:start position:0% +this this is the cell + + + align:start position:0% +this this is the cell +cycle + + align:start position:0% +cycle + + + align:start position:0% +cycle +uh the cell here moves away from The + + align:start position:0% +uh the cell here moves away from The + + + align:start position:0% +uh the cell here moves away from The +ventricle but when I say the cell I + + align:start position:0% +ventricle but when I say the cell I + + + align:start position:0% +ventricle but when I say the cell I +really mean the nucleus cell because + + align:start position:0% +really mean the nucleus cell because + + + align:start position:0% +really mean the nucleus cell because +it's ATT + + align:start position:0% + + + + align:start position:0% + +attached to the P out here to The + + align:start position:0% +attached to the P out here to The + + + align:start position:0% +attached to the P out here to The +ventricle + + align:start position:0% +ventricle + + + align:start position:0% +ventricle +here but it moves away from The + + align:start position:0% +here but it moves away from The + + + align:start position:0% +here but it moves away from The +ventricle in order to synthesize its DNA + + align:start position:0% +ventricle in order to synthesize its DNA + + + align:start position:0% +ventricle in order to synthesize its DNA +moves towards the ventricle in order to + + align:start position:0% +moves towards the ventricle in order to + + + align:start position:0% +moves towards the ventricle in order to +undergo + + align:start position:0% +undergo + + + align:start position:0% +undergo +mitosis and it can undergo + + align:start position:0% +mitosis and it can undergo + + + align:start position:0% +mitosis and it can undergo +mitosis with a symmetric split or an + + align:start position:0% +mitosis with a symmetric split or an + + + align:start position:0% +mitosis with a symmetric split or an +asymmetric + + align:start position:0% +asymmetric + + + align:start position:0% +asymmetric +split when it spits split symmetrically + + align:start position:0% +split when it spits split symmetrically + + + align:start position:0% +split when it spits split symmetrically +it tends to submit uh to split at a + + align:start position:0% +it tends to submit uh to split at a + + + align:start position:0% +it tends to submit uh to split at a +along a line that's at right angles to + + align:start position:0% +along a line that's at right angles to + + + align:start position:0% +along a line that's at right angles to +the ventricular + + align:start position:0% +the ventricular + + + align:start position:0% +the ventricular +surface and when it does that the + + align:start position:0% +surface and when it does that the + + + align:start position:0% +surface and when it does that the +distribution of proteins in the + + align:start position:0% +distribution of proteins in the + + + align:start position:0% +distribution of proteins in the +cell there's two proteins in particular + + align:start position:0% +cell there's two proteins in particular + + + align:start position:0% +cell there's two proteins in particular +uh tends to be pretty even in the two + + align:start position:0% +uh tends to be pretty even in the two + + + align:start position:0% +uh tends to be pretty even in the two +daughter cells so the two uh daughter + + align:start position:0% +daughter cells so the two uh daughter + + + align:start position:0% +daughter cells so the two uh daughter +cells will behave pretty similarly + + align:start position:0% +cells will behave pretty similarly + + + align:start position:0% +cells will behave pretty similarly +basically they became they remain stem + + align:start position:0% +basically they became they remain stem + + + align:start position:0% +basically they became they remain stem +cells they keep dividing okay + + align:start position:0% +cells they keep dividing okay + + + align:start position:0% +cells they keep dividing okay +but when it splits + + align:start position:0% +but when it splits + + + align:start position:0% +but when it splits +asymmetrically you end up with a very + + align:start position:0% +asymmetrically you end up with a very + + + align:start position:0% +asymmetrically you end up with a very +uneven distribution of those proteins + + align:start position:0% +uneven distribution of those proteins + + + align:start position:0% +uneven distribution of those proteins +Notch and numb they're + + align:start position:0% +Notch and numb they're + + + align:start position:0% +Notch and numb they're +called uh and now you get the two cells + + align:start position:0% +called uh and now you get the two cells + + + align:start position:0% +called uh and now you get the two cells +behave differently one remains a stem + + align:start position:0% +behave differently one remains a stem + + + align:start position:0% +behave differently one remains a stem +cell it keeps dividing the other one + + align:start position:0% +cell it keeps dividing the other one + + + align:start position:0% +cell it keeps dividing the other one +becomes + + align:start position:0% +becomes + + + align:start position:0% +becomes +postotic and does something very + + align:start position:0% +postotic and does something very + + + align:start position:0% +postotic and does something very +differently it migrates + + align:start position:0% +differently it migrates + + + align:start position:0% +differently it migrates +away and in many cases the migration is + + align:start position:0% +away and in many cases the migration is + + + align:start position:0% +away and in many cases the migration is +simply + + align:start position:0% +simply + + + align:start position:0% +simply +like over here in the cell cycle the + + align:start position:0% +like over here in the cell cycle the + + + align:start position:0% +like over here in the cell cycle the +nucleus just moves away from The + + align:start position:0% +nucleus just moves away from The + + + align:start position:0% +nucleus just moves away from The +ventricle it can be doing that the + + align:start position:0% +ventricle it can be doing that the + + + align:start position:0% +ventricle it can be doing that the +attachments can remain and kahal saw + + align:start position:0% +attachments can remain and kahal saw + + + align:start position:0% +attachments can remain and kahal saw +things like this + + align:start position:0% +things like this + + + align:start position:0% +things like this +um these are the way they look in GOI in + + align:start position:0% +um these are the way they look in GOI in + + + align:start position:0% +um these are the way they look in GOI in +many cases he might have been looking at + + align:start position:0% +many cases he might have been looking at + + + align:start position:0% +many cases he might have been looking at +two cells here but in some cases they + + align:start position:0% +two cells here but in some cases they + + + align:start position:0% +two cells here but in some cases they +might might be cells with two + + align:start position:0% +might might be cells with two + + + align:start position:0% +might might be cells with two +nuclei here's a cell that's lost it's + + align:start position:0% +nuclei here's a cell that's lost it's + + + align:start position:0% +nuclei here's a cell that's lost it's +external process okay all of these and + + align:start position:0% +external process okay all of these and + + + align:start position:0% +external process okay all of these and +here they've regained the attachment to + + align:start position:0% +here they've regained the attachment to + + + align:start position:0% +here they've regained the attachment to +the Pia and when the nucleus just moves + + align:start position:0% +the Pia and when the nucleus just moves + + + align:start position:0% +the Pia and when the nucleus just moves +further and further from The ventricle + + align:start position:0% +further and further from The ventricle + + + align:start position:0% +further and further from The ventricle +and never returns it's we say it's + + align:start position:0% +and never returns it's we say it's + + + align:start position:0% +and never returns it's we say it's +migrating we say it's migrating by + + align:start position:0% +migrating we say it's migrating by + + + align:start position:0% +migrating we say it's migrating by +nuclear + + align:start position:0% +nuclear + + + align:start position:0% +nuclear +translocation first type of migration + + align:start position:0% +translocation first type of migration + + + align:start position:0% +translocation first type of migration +okay here's his picture of the chick's + + align:start position:0% +okay here's his picture of the chick's + + + align:start position:0% +okay here's his picture of the chick's +spinal cord and the third day of + + align:start position:0% +spinal cord and the third day of + + + align:start position:0% +spinal cord and the third day of +incubation chicks grow up very fast + + align:start position:0% +incubation chicks grow up very fast + + + align:start position:0% +incubation chicks grow up very fast +they're favorite in know embryologist + + align:start position:0% +they're favorite in know embryologist + + + align:start position:0% +they're favorite in know embryologist +because you can cut a little window in + + align:start position:0% +because you can cut a little window in + + + align:start position:0% +because you can cut a little window in +the egg and you can look at these things + + align:start position:0% +the egg and you can look at these things + + + align:start position:0% +the egg and you can look at these things +happening okay and note that some of the + + align:start position:0% +happening okay and note that some of the + + + align:start position:0% +happening okay and note that some of the +cells are right near the ventricle but + + align:start position:0% +cells are right near the ventricle but + + + align:start position:0% +cells are right near the ventricle but +all of them that he shows in this + + align:start position:0% +all of them that he shows in this + + + align:start position:0% +all of them that he shows in this +particular picture are attached to the + + align:start position:0% + + + + align:start position:0% + +Pia so it's really similar to the roof + + align:start position:0% +Pia so it's really similar to the roof + + + align:start position:0% +Pia so it's really similar to the roof +plate and floor plate there it's just + + align:start position:0% +plate and floor plate there it's just + + + align:start position:0% +plate and floor plate there it's just +that this s a lot longer here and + + align:start position:0% +that this s a lot longer here and + + + align:start position:0% +that this s a lot longer here and +there's more of + + align:start position:0% +there's more of + + + align:start position:0% +there's more of +them all right well if you look at other + + align:start position:0% +them all right well if you look at other + + + align:start position:0% +them all right well if you look at other +day three + + align:start position:0% +day three + + + align:start position:0% +day three +pictures + + align:start position:0% +pictures + + + align:start position:0% +pictures +uh you'll let's just look at that right + + align:start position:0% +uh you'll let's just look at that right + + + align:start position:0% +uh you'll let's just look at that right +now here's another dayree + + align:start position:0% +now here's another dayree + + + align:start position:0% +now here's another dayree +picture GOI is + + align:start position:0% +picture GOI is + + + align:start position:0% +picture GOI is +selected sometimes you're getting more + + align:start position:0% +selected sometimes you're getting more + + + align:start position:0% +selected sometimes you're getting more +advanced cells when you're looking at + + align:start position:0% +advanced cells when you're looking at + + + align:start position:0% +advanced cells when you're looking at +developing animals sometimes you're + + align:start position:0% +developing animals sometimes you're + + + align:start position:0% +developing animals sometimes you're +getting uh the more the early developing + + align:start position:0% +getting uh the more the early developing + + + align:start position:0% +getting uh the more the early developing +cells but you see on that same day + + align:start position:0% +cells but you see on that same day + + + align:start position:0% +cells but you see on that same day +perhaps later in the day + + align:start position:0% +perhaps later in the day + + + align:start position:0% +perhaps later in the day +he was able to + + align:start position:0% +he was able to + + + align:start position:0% +he was able to +identify ventral and dorsal Roots foring + + align:start position:0% +identify ventral and dorsal Roots foring + + + align:start position:0% +identify ventral and dorsal Roots foring +how did he do + + align:start position:0% +how did he do + + + align:start position:0% +how did he do +that by recognizing + + align:start position:0% +that by recognizing + + + align:start position:0% +that by recognizing +something that he was probably the first + + align:start position:0% +something that he was probably the first + + + align:start position:0% +something that he was probably the first +to recognize and he named + + align:start position:0% +to recognize and he named + + + align:start position:0% +to recognize and he named +them the active growing tips that we + + align:start position:0% +them the active growing tips that we + + + align:start position:0% +them the active growing tips that we +call a growth cone processes extending + + align:start position:0% +call a growth cone processes extending + + + align:start position:0% +call a growth cone processes extending +out and when he saw that happening here + + align:start position:0% +out and when he saw that happening here + + + align:start position:0% +out and when he saw that happening here +he looked at them a little older he + + align:start position:0% +he looked at them a little older he + + + align:start position:0% +he looked at them a little older he +would see the growth cone further away + + align:start position:0% +would see the growth cone further away + + + align:start position:0% +would see the growth cone further away +he could see that an ax an axon was + + align:start position:0% +he could see that an ax an axon was + + + align:start position:0% +he could see that an ax an axon was +growing forming a vental root so he + + align:start position:0% +growing forming a vental root so he + + + align:start position:0% +growing forming a vental root so he +started seeing + + align:start position:0% +started seeing + + + align:start position:0% +started seeing +that uh in day three of the + + align:start position:0% +that uh in day three of the + + + align:start position:0% +that uh in day three of the +chick he also grow saw growth cones + + align:start position:0% +chick he also grow saw growth cones + + + align:start position:0% +chick he also grow saw growth cones +within the spinal developing spinal cord + + align:start position:0% +within the spinal developing spinal cord + + + align:start position:0% +within the spinal developing spinal cord +and here he saw some of those cells of + + align:start position:0% +and here he saw some of those cells of + + + align:start position:0% +and here he saw some of those cells of +the neural crest that weren't in the CNS + + align:start position:0% +the neural crest that weren't in the CNS + + + align:start position:0% +the neural crest that weren't in the CNS +he saw saw them with two growth cones + + align:start position:0% +he saw saw them with two growth cones + + + align:start position:0% +he saw saw them with two growth cones +one growing out towards the periphery + + align:start position:0% +one growing out towards the periphery + + + align:start position:0% +one growing out towards the periphery +another one + + align:start position:0% +another one + + + align:start position:0% +another one +growing in towards the in and right into + + align:start position:0% +growing in towards the in and right into + + + align:start position:0% +growing in towards the in and right into +the neural + + align:start position:0% +the neural + + + align:start position:0% +the neural +tool okay that was Cal's work so + + align:start position:0% +tool okay that was Cal's work so + + + align:start position:0% +tool okay that was Cal's work so +here I'm asking how did neuroscientists + + align:start position:0% +here I'm asking how did neuroscientists + + + align:start position:0% +here I'm asking how did neuroscientists +come to know that there are at least two + + align:start position:0% +come to know that there are at least two + + + align:start position:0% +come to know that there are at least two +major modes of cell migration in the + + align:start position:0% +major modes of cell migration in the + + + align:start position:0% +major modes of cell migration in the +embryonic central nervous system here's + + align:start position:0% +embryonic central nervous system here's + + + align:start position:0% +embryonic central nervous system here's +what + + align:start position:0% +what + + + align:start position:0% +what +happened I just describe nuclear + + align:start position:0% +happened I just describe nuclear + + + align:start position:0% +happened I just describe nuclear +translocation as a type of + + align:start position:0% + + + + align:start position:0% + +migration like this picture here when + + align:start position:0% +migration like this picture here when + + + align:start position:0% +migration like this picture here when +these cells are moving like this one + + align:start position:0% +these cells are moving like this one + + + align:start position:0% +these cells are moving like this one +it's moved very far it's moved way out + + align:start position:0% +it's moved very far it's moved way out + + + align:start position:0% +it's moved very far it's moved way out +towards the peel surface if it never + + align:start position:0% +towards the peel surface if it never + + + align:start position:0% +towards the peel surface if it never +comes back because it's not in the cell + + align:start position:0% +comes back because it's not in the cell + + + align:start position:0% +comes back because it's not in the cell +cycle anymore it we say it's migrated + + align:start position:0% +cycle anymore it we say it's migrated + + + align:start position:0% +cycle anymore it we say it's migrated +okay and eventually it loses its + + align:start position:0% +okay and eventually it loses its + + + align:start position:0% +okay and eventually it loses its +process and usually loses both of its + + align:start position:0% +process and usually loses both of its + + + align:start position:0% +process and usually loses both of its +attachments to the piia on the one side + + align:start position:0% +attachments to the piia on the one side + + + align:start position:0% +attachments to the piia on the one side +and to The ventricle on the other + + align:start position:0% +and to The ventricle on the other + + + align:start position:0% +and to The ventricle on the other +okay that had been + + align:start position:0% +okay that had been + + + align:start position:0% +okay that had been +described had been seen by kahal it was + + align:start position:0% +described had been seen by kahal it was + + + align:start position:0% +described had been seen by kahal it was +described by Kent morest who was at + + align:start position:0% +described by Kent morest who was at + + + align:start position:0% +described by Kent morest who was at +Harvard and then moved to University of + + align:start position:0% +Harvard and then moved to University of + + + align:start position:0% +Harvard and then moved to University of +Connecticut and then a man named POS + + align:start position:0% +Connecticut and then a man named POS + + + align:start position:0% +Connecticut and then a man named POS +gorak also at Harvard but then he moved + + align:start position:0% +gorak also at Harvard but then he moved + + + align:start position:0% +gorak also at Harvard but then he moved +to Yale he discovered he worked on a + + align:start position:0% +to Yale he discovered he worked on a + + + align:start position:0% +to Yale he discovered he worked on a +different part of the brain and he + + align:start position:0% +different part of the brain and he + + + align:start position:0% +different part of the brain and he +worked on primates he discovered + + align:start position:0% +worked on primates he discovered + + + align:start position:0% +worked on primates he discovered +evidence that in + + align:start position:0% +evidence that in + + + align:start position:0% +evidence that in +primates that is not house cells + + align:start position:0% +primates that is not house cells + + + align:start position:0% +primates that is not house cells +migrated they attached to a G cell that + + align:start position:0% +migrated they attached to a G cell that + + + align:start position:0% +migrated they attached to a G cell that +was elongated and they used the G cell + + align:start position:0% +was elongated and they used the G cell + + + align:start position:0% +was elongated and they used the G cell +sort of as a lad and they moved along it + + align:start position:0% +sort of as a lad and they moved along it + + + align:start position:0% +sort of as a lad and they moved along it +so he said that's the way cells in the + + align:start position:0% +so he said that's the way cells in the + + + align:start position:0% +so he said that's the way cells in the +central nervous system migrate and there + + align:start position:0% +central nervous system migrate and there + + + align:start position:0% +central nervous system migrate and there +actually became a sort of a conflict + + align:start position:0% +actually became a sort of a conflict + + + align:start position:0% +actually became a sort of a conflict +between these two views which was really + + align:start position:0% +between these two views which was really + + + align:start position:0% +between these two views which was really +silly because as you might expect both + + align:start position:0% +silly because as you might expect both + + + align:start position:0% +silly because as you might expect both +occur + + align:start position:0% +occur + + + align:start position:0% +occur +okay and I want you to know how that + + align:start position:0% +okay and I want you to know how that + + + align:start position:0% +okay and I want you to know how that +argument was + + align:start position:0% +argument was + + + align:start position:0% +argument was +settled + + align:start position:0% +settled + + + align:start position:0% +settled +by proof that nuclear + + align:start position:0% +by proof that nuclear + + + align:start position:0% +by proof that nuclear +translocation is not just in the spinal + + align:start position:0% +translocation is not just in the spinal + + + align:start position:0% +translocation is not just in the spinal +cord but right in the brain can be the + + align:start position:0% +cord but right in the brain can be the + + + align:start position:0% +cord but right in the brain can be the +major mode of + + align:start position:0% + + + + align:start position:0% + +movement now we know there's other kinds + + align:start position:0% +movement now we know there's other kinds + + + align:start position:0% +movement now we know there's other kinds +of cell movement too along other + + align:start position:0% +of cell movement too along other + + + align:start position:0% +of cell movement too along other +substrate factors but we're just going + + align:start position:0% +substrate factors but we're just going + + + align:start position:0% +substrate factors but we're just going +to talk about this and we'll talk more + + align:start position:0% +to talk about this and we'll talk more + + + align:start position:0% +to talk about this and we'll talk more +about guidance by radial real cells much + + align:start position:0% +about guidance by radial real cells much + + + align:start position:0% +about guidance by radial real cells much +later when we talk about development of + + align:start position:0% +later when we talk about development of + + + align:start position:0% +later when we talk about development of +Cortex but let's talk about a study + + align:start position:0% +Cortex but let's talk about a study + + + align:start position:0% +Cortex but let's talk about a study +using it was by these two people morest + + align:start position:0% +using it was by these two people morest + + + align:start position:0% +using it was by these two people morest +and Valerie domask who was a student of + + align:start position:0% +and Valerie domask who was a student of + + + align:start position:0% +and Valerie domask who was a student of +Naas here at MIT that went to work with + + align:start position:0% +Naas here at MIT that went to work with + + + align:start position:0% +Naas here at MIT that went to work with +mores this will be the just briefly the + + align:start position:0% +mores this will be the just briefly the + + + align:start position:0% +mores this will be the just briefly the +last topic they used they were studying + + align:start position:0% +last topic they used they were studying + + + align:start position:0% +last topic they used they were studying +a cell in the + + align:start position:0% +a cell in the + + + align:start position:0% +a cell in the +tectum that was very interesting because + + align:start position:0% +tectum that was very interesting because + + + align:start position:0% +tectum that was very interesting because +it always if you look at the at the + + align:start position:0% +it always if you look at the at the + + + align:start position:0% +it always if you look at the at the +adult you would see the cell and its + + align:start position:0% +adult you would see the cell and its + + + align:start position:0% +adult you would see the cell and its +dendrites here near the surface of the + + align:start position:0% +dendrites here near the surface of the + + + align:start position:0% +dendrites here near the surface of the +tectum it always the initial part of its + + align:start position:0% +tectum it always the initial part of its + + + align:start position:0% +tectum it always the initial part of its +axon had this peculiar bend it looks + + align:start position:0% +axon had this peculiar bend it looks + + + align:start position:0% +axon had this peculiar bend it looks +like looks like a the crook in a + + align:start position:0% +like looks like a the crook in a + + + align:start position:0% +like looks like a the crook in a +shepherd's staff so it was called The + + align:start position:0% +shepherd's staff so it was called The + + + align:start position:0% +shepherd's staff so it was called The +Shepherd's crook + + align:start position:0% +Shepherd's crook + + + align:start position:0% +Shepherd's crook +cell that was the name it had they look + + align:start position:0% +cell that was the name it had they look + + + align:start position:0% +cell that was the name it had they look +at earlier and earlier periods they kept + + align:start position:0% +at earlier and earlier periods they kept + + + align:start position:0% +at earlier and earlier periods they kept +seeing the crook but it they found a + + align:start position:0% +seeing the crook but it they found a + + + align:start position:0% +seeing the crook but it they found a +period where the axon was just beginning + + align:start position:0% +period where the axon was just beginning + + + align:start position:0% +period where the axon was just beginning +to form it had the peculiar Bend there's + + align:start position:0% +to form it had the peculiar Bend there's + + + align:start position:0% +to form it had the peculiar Bend there's +the growth cone and then they saw that + + align:start position:0% +the growth cone and then they saw that + + + align:start position:0% +the growth cone and then they saw that +well at that stage the cell body was way + + align:start position:0% +well at that stage the cell body was way + + + align:start position:0% +well at that stage the cell body was way +down here near The ventricle the cell + + align:start position:0% +down here near The ventricle the cell + + + align:start position:0% +down here near The ventricle the cell +body hadn't moved yet it hadn't migrated + + align:start position:0% +body hadn't moved yet it hadn't migrated + + + align:start position:0% +body hadn't moved yet it hadn't migrated +and yet the axon was already forming so + + align:start position:0% +and yet the axon was already forming so + + + align:start position:0% +and yet the axon was already forming so +you have to think of the realize that + + align:start position:0% +you have to think of the realize that + + + align:start position:0% +you have to think of the realize that +the cell extends all the way from + + align:start position:0% +the cell extends all the way from + + + align:start position:0% +the cell extends all the way from +ventricle to the midbrain surface here + + align:start position:0% +ventricle to the midbrain surface here + + + align:start position:0% +ventricle to the midbrain surface here +the axon is forming here long before the + + align:start position:0% +the axon is forming here long before the + + + align:start position:0% +the axon is forming here long before the +cell body is there and then the cell + + align:start position:0% +cell body is there and then the cell + + + align:start position:0% +cell body is there and then the cell +body is moving as you see here + + align:start position:0% +body is moving as you see here + + + align:start position:0% +body is moving as you see here +and finally gets to the point where the + + align:start position:0% +and finally gets to the point where the + + + align:start position:0% +and finally gets to the point where the +axone + + align:start position:0% +axone + + + align:start position:0% +axone +originates they looked at many closely + + align:start position:0% +originates they looked at many closely + + + align:start position:0% +originates they looked at many closely +embryos closely spaced in age and they + + align:start position:0% +embryos closely spaced in age and they + + + align:start position:0% +embryos closely spaced in age and they +saw all these + + align:start position:0% +saw all these + + + align:start position:0% +saw all these +stages and they reported it at the + + align:start position:0% +stages and they reported it at the + + + align:start position:0% +stages and they reported it at the +American Association of anatomists + + align:start position:0% +American Association of anatomists + + + align:start position:0% +American Association of anatomists +meeting where a group called The the + + align:start position:0% + + + + align:start position:0% + +uh the kahal club met uh was a favorite + + align:start position:0% +uh the kahal club met uh was a favorite + + + align:start position:0% +uh the kahal club met uh was a favorite +meeting of neuroanatomists at that time + + align:start position:0% +meeting of neuroanatomists at that time + + + align:start position:0% +meeting of neuroanatomists at that time +it before there was a society for + + align:start position:0% +it before there was a society for + + + align:start position:0% +it before there was a society for +Neuroscience but their talk was so + + align:start position:0% +Neuroscience but their talk was so + + + align:start position:0% +Neuroscience but their talk was so +convincing and rockich was there he + + align:start position:0% +convincing and rockich was there he + + + align:start position:0% +convincing and rockich was there he +agreed afterwards okay there's got to be + + align:start position:0% +agreed afterwards okay there's got to be + + + align:start position:0% +agreed afterwards okay there's got to be +at least two kinds of migration because + + align:start position:0% +at least two kinds of migration because + + + align:start position:0% +at least two kinds of migration because +I know that that's not how it happens in + + align:start position:0% +I know that that's not how it happens in + + + align:start position:0% +I know that that's not how it happens in +the + + align:start position:0% +the + + + align:start position:0% +the +neocortex so that's the story of how + + align:start position:0% +neocortex so that's the story of how + + + align:start position:0% +neocortex so that's the story of how +we're we became more certain that there + + align:start position:0% +we're we became more certain that there + + + align:start position:0% +we're we became more certain that there +were two different kinds of migration + + align:start position:0% +were two different kinds of migration + + + align:start position:0% +were two different kinds of migration +okay so that's where we're going to stop + + align:start position:0% +okay so that's where we're going to stop + + + align:start position:0% +okay so that's where we're going to stop +today uh we've already talked about + + align:start position:0% +today uh we've already talked about + + + align:start position:0% +today uh we've already talked about +this so I guess we finished except for a + + align:start position:0% +this so I guess we finished except for a + + + align:start position:0% +this so I guess we finished except for a +review so I'll post these slides you can + + align:start position:0% +review so I'll post these slides you can + + + align:start position:0% +review so I'll post these slides you can +go over them and we'll be able to talk + + align:start position:0% +go over them and we'll be able to talk + + + align:start position:0% +go over them and we'll be able to talk +about the the next chapter the adults + + align:start position:0% +about the the next chapter the adults + + + align:start position:0% +about the the next chapter the adults +final court on + + align:start position:0% +final court on + + + align:start position:0% +final court on +Friday \ No newline at end of file diff --git a/4N68XQDT38c.txt b/4N68XQDT38c.txt new file mode 100644 index 0000000000000000000000000000000000000000..f8f3248fe301fdb7315fd64703384ec47d08047b --- /dev/null +++ b/4N68XQDT38c.txt @@ -0,0 +1,14179 @@ +align:start position:0% + +the following content is provided by mit + + align:start position:0% +the following content is provided by mit + + + align:start position:0% +the following content is provided by mit +opencourseware under a creative commons + + align:start position:0% +opencourseware under a creative commons + + + align:start position:0% +opencourseware under a creative commons +license + + align:start position:0% +license + + + align:start position:0% +license +additional information about our license + + align:start position:0% +additional information about our license + + + align:start position:0% +additional information about our license +and mit opencourseware in general is + + align:start position:0% +and mit opencourseware in general is + + + align:start position:0% +and mit opencourseware in general is +available at ocw.mit.edu + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +now + + align:start position:0% + + + + align:start position:0% + +this + + align:start position:0% +this + + + align:start position:0% +this +should be the most interesting class of + + align:start position:0% +should be the most interesting class of + + + align:start position:0% +should be the most interesting class of +the semester + + align:start position:0% +the semester + + + align:start position:0% +the semester +possible + + align:start position:0% + + + + align:start position:0% + +what y'all think of possible + + align:start position:0% +what y'all think of possible + + + align:start position:0% +what y'all think of possible +oh this robert we were discussing + + align:start position:0% +oh this robert we were discussing + + + align:start position:0% +oh this robert we were discussing +earlier + + align:start position:0% + + + + align:start position:0% + +why + + align:start position:0% +why + + + align:start position:0% +why +well let's go let's do the facts first + + align:start position:0% +well let's go let's do the facts first + + + align:start position:0% +well let's go let's do the facts first +let's tell the story + + align:start position:0% +let's tell the story + + + align:start position:0% +let's tell the story +let's start uh let's just go back and + + align:start position:0% +let's start uh let's just go back and + + + align:start position:0% +let's start uh let's just go back and +forth round around until we get it done + + align:start position:0% + + + + align:start position:0% + +well i think what the author is doing + + align:start position:0% +well i think what the author is doing + + + align:start position:0% +well i think what the author is doing +there uh is emphasizing + + align:start position:0% +there uh is emphasizing + + + align:start position:0% +there uh is emphasizing +that + + align:start position:0% +that + + + align:start position:0% +that +uh the first principle of moral behavior + + align:start position:0% +uh the first principle of moral behavior + + + align:start position:0% +uh the first principle of moral behavior +is family + + align:start position:0% +is family + + + align:start position:0% +is family +kinship + + align:start position:0% + + + + align:start position:0% + +that uh we have to know his lineage + + align:start position:0% +that uh we have to know his lineage + + + align:start position:0% +that uh we have to know his lineage +before we can know him + + align:start position:0% +before we can know him + + + align:start position:0% +before we can know him +and whatever he does i think there's + + align:start position:0% +and whatever he does i think there's + + + align:start position:0% +and whatever he does i think there's +another and that and um + + align:start position:0% +another and that and um + + + align:start position:0% +another and that and um +that's a big difference + + align:start position:0% +that's a big difference + + + align:start position:0% +that's a big difference +between + + align:start position:0% + + + + align:start position:0% + +possible and + + align:start position:0% + + + + align:start position:0% + +mallory + + align:start position:0% +mallory + + + align:start position:0% +mallory +this is your this is your + + align:start position:0% +this is your this is your + + + align:start position:0% +this is your this is your +king office legend + + align:start position:0% +king office legend + + + align:start position:0% +king office legend +in the first form + + align:start position:0% +in the first form + + + align:start position:0% +in the first form +okay this one here + + align:start position:0% +okay this one here + + + align:start position:0% +okay this one here +uh + + align:start position:0% +uh + + + align:start position:0% +uh +that is that there's a lot of attention + + align:start position:0% +that is that there's a lot of attention + + + align:start position:0% +that is that there's a lot of attention +given to um + + align:start position:0% +given to um + + + align:start position:0% +given to um +the morality of being a knight + + align:start position:0% +the morality of being a knight + + + align:start position:0% +the morality of being a knight +uh but the first principle is uh first + + align:start position:0% +uh but the first principle is uh first + + + align:start position:0% +uh but the first principle is uh first +principle i think is kinship + + align:start position:0% +principle i think is kinship + + + align:start position:0% +principle i think is kinship +and an interesting principle is + + align:start position:0% +and an interesting principle is + + + align:start position:0% +and an interesting principle is +that it's immoral + + align:start position:0% + + + + align:start position:0% + +to do to mistreat a kinship a relative + + align:start position:0% +to do to mistreat a kinship a relative + + + align:start position:0% +to do to mistreat a kinship a relative +even if you don't know that this direct + + align:start position:0% +even if you don't know that this direct + + + align:start position:0% +even if you don't know that this direct +person is a relative + + align:start position:0% + + + + align:start position:0% + +remember that you're not supposed + + align:start position:0% + + + + align:start position:0% + +to respond that's right + + align:start position:0% + + + + align:start position:0% + +right + + align:start position:0% + + + + align:start position:0% + +so and and there's there's this big to + + align:start position:0% +so and and there's there's this big to + + + align:start position:0% +so and and there's there's this big to +do about all of these relationships + + align:start position:0% +do about all of these relationships + + + align:start position:0% +do about all of these relationships +and you don't discover them immediately + + align:start position:0% +and you don't discover them immediately + + + align:start position:0% +and you don't discover them immediately +you find them out later + + align:start position:0% +you find them out later + + + align:start position:0% +you find them out later +okay so uh + + align:start position:0% +okay so uh + + + align:start position:0% +okay so uh +parzival's father + + align:start position:0% + + + + align:start position:0% + +goes out + + align:start position:0% +goes out + + + align:start position:0% +goes out +gets married + + align:start position:0% + + + + align:start position:0% + +uh to a no doesn't does a heroic deed + + align:start position:0% +uh to a no doesn't does a heroic deed + + + align:start position:0% +uh to a no doesn't does a heroic deed +marry is a queen as a result of it + + align:start position:0% +marry is a queen as a result of it + + + align:start position:0% +marry is a queen as a result of it +thanks + + align:start position:0% +thanks + + + align:start position:0% +thanks +uh + + align:start position:0% +uh + + + align:start position:0% +uh +gets tired of being a king and goes back + + align:start position:0% +gets tired of being a king and goes back + + + align:start position:0% +gets tired of being a king and goes back +out on the road so to speak + + align:start position:0% +out on the road so to speak + + + align:start position:0% +out on the road so to speak +mary's again + + align:start position:0% +mary's again + + + align:start position:0% +mary's again +finds no legal or moral problem in doing + + align:start position:0% +finds no legal or moral problem in doing + + + align:start position:0% +finds no legal or moral problem in doing +that because + + align:start position:0% +that because + + + align:start position:0% +that because +one uh wife was a pagan and the other + + align:start position:0% +one uh wife was a pagan and the other + + + align:start position:0% +one uh wife was a pagan and the other +one was a christian + + align:start position:0% + + + + align:start position:0% + +well keep going keep y'all getting i + + align:start position:0% +well keep going keep y'all getting i + + + align:start position:0% +well keep going keep y'all getting i +want to hear more about these stories + + align:start position:0% +want to hear more about these stories + + + align:start position:0% +want to hear more about these stories +you can and you can do it bullet wise + + align:start position:0% +you can and you can do it bullet wise + + + align:start position:0% +you can and you can do it bullet wise +just you don't have to go from the + + align:start position:0% +just you don't have to go from the + + + align:start position:0% +just you don't have to go from the +beginning to the end what what were some + + align:start position:0% +beginning to the end what what were some + + + align:start position:0% +beginning to the end what what were some +of the things that struck you about this + + align:start position:0% +of the things that struck you about this + + + align:start position:0% +of the things that struck you about this +and then we're going to tie it all in + + align:start position:0% +and then we're going to tie it all in + + + align:start position:0% +and then we're going to tie it all in +at the end + + align:start position:0% +at the end + + + align:start position:0% +at the end +make sure we get the facts straight + + align:start position:0% +make sure we get the facts straight + + + align:start position:0% +make sure we get the facts straight +first + + align:start position:0% + + + + align:start position:0% + +remember some of the things he did + + align:start position:0% + + + + align:start position:0% + +here's a loyalty + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% + + + + align:start position:0% + +yeah they are afraid that some other + + align:start position:0% +yeah they are afraid that some other + + + align:start position:0% +yeah they are afraid that some other +person + + align:start position:0% +person + + + align:start position:0% +person +might + + align:start position:0% +might + + + align:start position:0% +might +take over his property and do + + align:start position:0% +take over his property and do + + + align:start position:0% +take over his property and do +her and her child some harm + + align:start position:0% + + + + align:start position:0% + +she doesn't want him to be like his + + align:start position:0% + + + + align:start position:0% + +all father + + align:start position:0% + + + + align:start position:0% + +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +say that's for me + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +i don't i didn't remember that but i uh + + align:start position:0% +i don't i didn't remember that but i uh + + + align:start position:0% +i don't i didn't remember that but i uh +yes + + align:start position:0% + + + + align:start position:0% + +the fisher king + + align:start position:0% +the fisher king + + + align:start position:0% +the fisher king +now let's talk about the fisher king + + align:start position:0% +now let's talk about the fisher king + + + align:start position:0% +now let's talk about the fisher king +let's go into the fisher king in some + + align:start position:0% +let's go into the fisher king in some + + + align:start position:0% +let's go into the fisher king in some +detail + + align:start position:0% +detail + + + align:start position:0% +detail +okay + + align:start position:0% +okay + + + align:start position:0% +okay +when does he encounter the fisher king + + align:start position:0% + + + + align:start position:0% + +five + + align:start position:0% + + + + align:start position:0% + +this is the grail + + align:start position:0% +this is the grail + + + align:start position:0% +this is the grail +grail king + + align:start position:0% +grail king + + + align:start position:0% +grail king +uh + + align:start position:0% +uh + + + align:start position:0% +uh +and he doesn't know he's the grill king + + align:start position:0% +and he doesn't know he's the grill king + + + align:start position:0% +and he doesn't know he's the grill king +at first all he sees is a man out in a + + align:start position:0% +at first all he sees is a man out in a + + + align:start position:0% +at first all he sees is a man out in a +boat + + align:start position:0% +boat + + + align:start position:0% +boat +right + + align:start position:0% + + + + align:start position:0% + +right you can read uh quick portions of + + align:start position:0% +right you can read uh quick portions of + + + align:start position:0% +right you can read uh quick portions of +it + + align:start position:0% +it + + + align:start position:0% +it +that's legitimate + + align:start position:0% + + + + align:start position:0% + +right + + align:start position:0% + + + + align:start position:0% + +right + + align:start position:0% +right + + + align:start position:0% +right +and he didn't know he was the king at + + align:start position:0% +and he didn't know he was the king at + + + align:start position:0% +and he didn't know he was the king at +the time + + align:start position:0% + + + + align:start position:0% + +yes that's the point i'm getting it + + align:start position:0% +yes that's the point i'm getting it + + + align:start position:0% +yes that's the point i'm getting it +seems like everybody + + align:start position:0% +seems like everybody + + + align:start position:0% +seems like everybody +knows about this right + + align:start position:0% +knows about this right + + + align:start position:0% +knows about this right +but the other thing is that + + align:start position:0% +but the other thing is that + + + align:start position:0% +but the other thing is that +people come what they fault him for + + align:start position:0% +people come what they fault him for + + + align:start position:0% +people come what they fault him for +and i think in today's society + + align:start position:0% +and i think in today's society + + + align:start position:0% +and i think in today's society +would claim innocence because i didn't + + align:start position:0% +would claim innocence because i didn't + + + align:start position:0% +would claim innocence because i didn't +know i didn't know why you liked me but + + align:start position:0% +know i didn't know why you liked me but + + + align:start position:0% +know i didn't know why you liked me but +there he sort of feels like + + align:start position:0% +there he sort of feels like + + + align:start position:0% +there he sort of feels like +he feels guilty + + align:start position:0% +he feels guilty + + + align:start position:0% +he feels guilty +i should have asked the questions + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +the second uh the way i look at it the + + align:start position:0% +the second uh the way i look at it the + + + align:start position:0% +the second uh the way i look at it the +first principles of morality for him are + + align:start position:0% +first principles of morality for him are + + + align:start position:0% +first principles of morality for him are +kinship and the second set of principles + + align:start position:0% +kinship and the second set of principles + + + align:start position:0% +kinship and the second set of principles +are chivalrous + + align:start position:0% +are chivalrous + + + align:start position:0% +are chivalrous +which are connected too + + align:start position:0% +which are connected too + + + align:start position:0% +which are connected too +in some way + + align:start position:0% +in some way + + + align:start position:0% +in some way +uh but yeah let's let's i want to delve + + align:start position:0% +uh but yeah let's let's i want to delve + + + align:start position:0% +uh but yeah let's let's i want to delve +into this question + + align:start position:0% +into this question + + + align:start position:0% +into this question +yeah the the notion of admitting + + align:start position:0% +yeah the the notion of admitting + + + align:start position:0% +yeah the the notion of admitting +wrongdoing and wanting + + align:start position:0% +wrongdoing and wanting + + + align:start position:0% +wrongdoing and wanting +to atone for it atonement is sort of a + + align:start position:0% +to atone for it atonement is sort of a + + + align:start position:0% +to atone for it atonement is sort of a +major theme in this + + align:start position:0% +major theme in this + + + align:start position:0% +major theme in this +book + + align:start position:0% +book + + + align:start position:0% +book +um + + align:start position:0% +um + + + align:start position:0% +um +that to me the mistake or the sin seems + + align:start position:0% +that to me the mistake or the sin seems + + + align:start position:0% +that to me the mistake or the sin seems +sort of trivial like not + + align:start position:0% +sort of trivial like not + + + align:start position:0% +sort of trivial like not +not asking you a question out of + + align:start position:0% +not asking you a question out of + + + align:start position:0% +not asking you a question out of +politeness + + align:start position:0% + + + + align:start position:0% + +is not a compelling sin to me or + + align:start position:0% +is not a compelling sin to me or + + + align:start position:0% +is not a compelling sin to me or +compelling wrongdoing but + + align:start position:0% +compelling wrongdoing but + + + align:start position:0% +compelling wrongdoing but +it's what's used in the story and + + align:start position:0% +it's what's used in the story and + + + align:start position:0% +it's what's used in the story and +first of all right feels very guilty + + align:start position:0% +first of all right feels very guilty + + + align:start position:0% +first of all right feels very guilty +about it and wants to return for it like + + align:start position:0% +about it and wants to return for it like + + + align:start position:0% +about it and wants to return for it like +makes it his mission + + align:start position:0% +makes it his mission + + + align:start position:0% +makes it his mission +right that was my first make his way + + align:start position:0% +right that was my first make his way + + + align:start position:0% +right that was my first make his way +back to different yeah + + align:start position:0% +back to different yeah + + + align:start position:0% +back to different yeah +okay now + + align:start position:0% +okay now + + + align:start position:0% +okay now +i don't know if you all read joseph + + align:start position:0% +i don't know if you all read joseph + + + align:start position:0% +i don't know if you all read joseph +campbell + + align:start position:0% + + + + align:start position:0% + +okay uh + + align:start position:0% +okay uh + + + align:start position:0% +okay uh +the only reason i haven't assigned + + align:start position:0% +the only reason i haven't assigned + + + align:start position:0% +the only reason i haven't assigned +joseph campbell yet is that i can't + + align:start position:0% +joseph campbell yet is that i can't + + + align:start position:0% +joseph campbell yet is that i can't +figure out which one to assign + + align:start position:0% +figure out which one to assign + + + align:start position:0% +figure out which one to assign +because uh uh i'd have been reading four + + align:start position:0% +because uh uh i'd have been reading four + + + align:start position:0% +because uh uh i'd have been reading four +or five of them and watching + + align:start position:0% +or five of them and watching + + + align:start position:0% +or five of them and watching +uh + + align:start position:0% +uh + + + align:start position:0% +uh +this tv program + + align:start position:0% +this tv program + + + align:start position:0% +this tv program +where you know bill moyers + + align:start position:0% +where you know bill moyers + + + align:start position:0% +where you know bill moyers +he does one with bill moyers uh called + + align:start position:0% +he does one with bill moyers uh called + + + align:start position:0% +he does one with bill moyers uh called +the power of it + + align:start position:0% +the power of it + + + align:start position:0% +the power of it +and he's a spectacular lecturer and he's + + align:start position:0% +and he's a spectacular lecturer and he's + + + align:start position:0% +and he's a spectacular lecturer and he's +got some um i've got some video + + align:start position:0% +got some um i've got some video + + + align:start position:0% +got some um i've got some video +videotapes of his in his classes + + align:start position:0% +videotapes of his in his classes + + + align:start position:0% +videotapes of his in his classes +um + + align:start position:0% +um + + + align:start position:0% +um +so i think that uh well for me + + align:start position:0% +so i think that uh well for me + + + align:start position:0% +so i think that uh well for me +uh joe joseph campbell is one of my + + align:start position:0% +uh joe joseph campbell is one of my + + + align:start position:0% +uh joe joseph campbell is one of my +maybe top five if you want to put it + + align:start position:0% +maybe top five if you want to put it + + + align:start position:0% +maybe top five if you want to put it +that way scholars + + align:start position:0% +that way scholars + + + align:start position:0% +that way scholars +now here's the big issue that joseph + + align:start position:0% +now here's the big issue that joseph + + + align:start position:0% +now here's the big issue that joseph +campbell makes out of the question + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +campbell starts off + + align:start position:0% + + + + align:start position:0% + +with a + + align:start position:0% +with a + + + align:start position:0% +with a +poet by the name of t.s eliot + + align:start position:0% + + + + align:start position:0% + +got a nobel prize for literature + + align:start position:0% + + + + align:start position:0% + +and one of + + align:start position:0% +and one of + + + align:start position:0% +and one of +one of elliot's pieces + + align:start position:0% +one of elliot's pieces + + + align:start position:0% +one of elliot's pieces +is called the waste land + + align:start position:0% + + + + align:start position:0% + +and in the wasteland + + align:start position:0% + + + + align:start position:0% + +the wasteland is a place + + align:start position:0% +the wasteland is a place + + + align:start position:0% +the wasteland is a place +where everybody does what everybody else + + align:start position:0% +where everybody does what everybody else + + + align:start position:0% +where everybody does what everybody else +expects you to do + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so you never break out and find your + + align:start position:0% +so you never break out and find your + + + align:start position:0% +so you never break out and find your +individual + + align:start position:0% +individual + + + align:start position:0% +individual +what he calls bliss + + align:start position:0% +what he calls bliss + + + align:start position:0% +what he calls bliss +what i call destiny + + align:start position:0% +what i call destiny + + + align:start position:0% +what i call destiny +you never break out of that you're + + align:start position:0% +you never break out of that you're + + + align:start position:0% +you never break out of that you're +always you come in you learn the rules + + align:start position:0% +always you come in you learn the rules + + + align:start position:0% +always you come in you learn the rules +and you follow them + + align:start position:0% +and you follow them + + + align:start position:0% +and you follow them +okay + + align:start position:0% +okay + + + align:start position:0% +okay +uh which is good 99 of the time + + align:start position:0% +uh which is good 99 of the time + + + align:start position:0% +uh which is good 99 of the time +the question is when you break out + + align:start position:0% +the question is when you break out + + + align:start position:0% +the question is when you break out +and by what reason do you break out + + align:start position:0% + + + + align:start position:0% + +particle really wants to be a good night + + align:start position:0% +particle really wants to be a good night + + + align:start position:0% +particle really wants to be a good night +i'm sorry + + align:start position:0% +i'm sorry + + + align:start position:0% +i'm sorry +a + + align:start position:0% + + + + align:start position:0% + +competent night + + align:start position:0% +competent night + + + align:start position:0% +competent night +just playing with words good night okay + + align:start position:0% +just playing with words good night okay + + + align:start position:0% +just playing with words good night okay +uh and he's been taught very well + + align:start position:0% +uh and he's been taught very well + + + align:start position:0% +uh and he's been taught very well +remember his teacher + + align:start position:0% +remember his teacher + + + align:start position:0% +remember his teacher +and the teacher said told him + + align:start position:0% +and the teacher said told him + + + align:start position:0% +and the teacher said told him +virtually when you go to somebody's + + align:start position:0% +virtually when you go to somebody's + + + align:start position:0% +virtually when you go to somebody's +house you don't start a quiz you're + + align:start position:0% +house you don't start a quiz you're + + + align:start position:0% +house you don't start a quiz you're +asking uh questions + + align:start position:0% +asking uh questions + + + align:start position:0% +asking uh questions +that's one of the rules of sugar + + align:start position:0% +that's one of the rules of sugar + + + align:start position:0% +that's one of the rules of sugar +and parcel wants to be + + align:start position:0% +and parcel wants to be + + + align:start position:0% +and parcel wants to be +uh true to all the rules of shiva + + align:start position:0% +uh true to all the rules of shiva + + + align:start position:0% +uh true to all the rules of shiva +but he's sitting there + + align:start position:0% +but he's sitting there + + + align:start position:0% +but he's sitting there +talking to his host + + align:start position:0% +talking to his host + + + align:start position:0% +talking to his host +and his host is in pain + + align:start position:0% +and his host is in pain + + + align:start position:0% +and his host is in pain +and the authors have made it clear that + + align:start position:0% +and the authors have made it clear that + + + align:start position:0% +and the authors have made it clear that +this is the worst kind of pain that a + + align:start position:0% +this is the worst kind of pain that a + + + align:start position:0% +this is the worst kind of pain that a +man can endure + + align:start position:0% +man can endure + + + align:start position:0% +man can endure +okay now actually the worst kind of pain + + align:start position:0% +okay now actually the worst kind of pain + + + align:start position:0% +okay now actually the worst kind of pain +i've heard i've had six physicians tell + + align:start position:0% +i've heard i've had six physicians tell + + + align:start position:0% +i've heard i've had six physicians tell +me + + align:start position:0% +me + + + align:start position:0% +me +that kidney stones the worst kind of + + align:start position:0% +that kidney stones the worst kind of + + + align:start position:0% +that kidney stones the worst kind of +pain a man can endure it's man's + + align:start position:0% +pain a man can endure it's man's + + + align:start position:0% +pain a man can endure it's man's +equivalent + + align:start position:0% +equivalent + + + align:start position:0% +equivalent +of a woman's childbirth + + align:start position:0% +of a woman's childbirth + + + align:start position:0% +of a woman's childbirth +natural childhood + + align:start position:0% +natural childhood + + + align:start position:0% +natural childhood +worse than pains in their army + + align:start position:0% +worse than pains in their army + + + align:start position:0% +worse than pains in their army +and i've had them i know + + align:start position:0% +and i've had them i know + + + align:start position:0% +and i've had them i know +but + + align:start position:0% +but + + + align:start position:0% +but +there is nothing + + align:start position:0% +there is nothing + + + align:start position:0% +there is nothing +fearful attached + + align:start position:0% +fearful attached + + + align:start position:0% +fearful attached +to kidney stones + + align:start position:0% + + + + align:start position:0% + +i have not lost my manhood + + align:start position:0% +i have not lost my manhood + + + align:start position:0% +i have not lost my manhood +when i pass a kidney stone this man lost + + align:start position:0% +when i pass a kidney stone this man lost + + + align:start position:0% +when i pass a kidney stone this man lost +his mouth + + align:start position:0% +his mouth + + + align:start position:0% +his mouth +not only that but the tip of that thing + + align:start position:0% +not only that but the tip of that thing + + + align:start position:0% +not only that but the tip of that thing +is still stuck in it + + align:start position:0% +is still stuck in it + + + align:start position:0% +is still stuck in it +so then you ask yourself if if possible + + align:start position:0% +so then you ask yourself if if possible + + + align:start position:0% +so then you ask yourself if if possible +is going to + + align:start position:0% +is going to + + + align:start position:0% +is going to +lift himself up above the rules + + align:start position:0% +lift himself up above the rules + + + align:start position:0% +lift himself up above the rules +now is the time to do it okay you got a + + align:start position:0% +now is the time to do it okay you got a + + + align:start position:0% +now is the time to do it okay you got a +colleague sitting there suffering the + + align:start position:0% +colleague sitting there suffering the + + + align:start position:0% +colleague sitting there suffering the +worst pain they could ever suffer and + + align:start position:0% +worst pain they could ever suffer and + + + align:start position:0% +worst pain they could ever suffer and +it's going to die of it + + align:start position:0% +it's going to die of it + + + align:start position:0% +it's going to die of it +least you could do is say oh my god i + + align:start position:0% +least you could do is say oh my god i + + + align:start position:0% +least you could do is say oh my god i +feel sorry for you + + align:start position:0% +feel sorry for you + + + align:start position:0% +feel sorry for you +possibly didn't do it + + align:start position:0% +possibly didn't do it + + + align:start position:0% +possibly didn't do it +now there's another game that everybody + + align:start position:0% +now there's another game that everybody + + + align:start position:0% +now there's another game that everybody +plays particularly parents + + align:start position:0% +plays particularly parents + + + align:start position:0% +plays particularly parents +there's some lessons you cannot teach a + + align:start position:0% +there's some lessons you cannot teach a + + + align:start position:0% +there's some lessons you cannot teach a +child + + align:start position:0% +child + + + align:start position:0% +child +by giving them the answer first + + align:start position:0% + + + + align:start position:0% + +you got to say you got to put the child + + align:start position:0% +you got to say you got to put the child + + + align:start position:0% +you got to say you got to put the child +in this situation you got everybody does + + align:start position:0% +in this situation you got everybody does + + + align:start position:0% +in this situation you got everybody does +it there are certain situations you get + + align:start position:0% +it there are certain situations you get + + + align:start position:0% +it there are certain situations you get +in + + align:start position:0% +in + + + align:start position:0% +in +where + + align:start position:0% +where + + + align:start position:0% +where +uh + + align:start position:0% +uh + + + align:start position:0% +uh +you just can't tell if you're going to + + align:start position:0% +you just can't tell if you're going to + + + align:start position:0% +you just can't tell if you're going to +give a person some kind of a test you + + align:start position:0% +give a person some kind of a test you + + + align:start position:0% +give a person some kind of a test you +can't tell them + + align:start position:0% +can't tell them + + + align:start position:0% +can't tell them +uh you know uh certain things like for + + align:start position:0% +uh you know uh certain things like for + + + align:start position:0% +uh you know uh certain things like for +example when i had my first test on the + + align:start position:0% +example when i had my first test on the + + + align:start position:0% +example when i had my first test on the +job they couldn't tell me or we got that + + align:start position:0% +job they couldn't tell me or we got that + + + align:start position:0% +job they couldn't tell me or we got that +covered in case you mess up + + align:start position:0% +covered in case you mess up + + + align:start position:0% +covered in case you mess up +i had to believe that this was it + + align:start position:0% +i had to believe that this was it + + + align:start position:0% +i had to believe that this was it +okay + + align:start position:0% +okay + + + align:start position:0% +okay +all right so they couldn't tell him + + align:start position:0% +all right so they couldn't tell him + + + align:start position:0% +all right so they couldn't tell him +to ask that question + + align:start position:0% +to ask that question + + + align:start position:0% +to ask that question +and that the result would be that he + + align:start position:0% +and that the result would be that he + + + align:start position:0% +and that the result would be that he +would become the grail king + + align:start position:0% +would become the grail king + + + align:start position:0% +would become the grail king +he had to break out of the rule + + align:start position:0% +he had to break out of the rule + + + align:start position:0% +he had to break out of the rule +and show that he was worth it + + align:start position:0% + + + + align:start position:0% + +so there's that big issue now with the + + align:start position:0% +so there's that big issue now with the + + + align:start position:0% +so there's that big issue now with the +grail king + + align:start position:0% +grail king + + + align:start position:0% +grail king +and + + align:start position:0% +and + + + align:start position:0% +and +um + + align:start position:0% + + + + align:start position:0% + +possible uh felt bad and + + align:start position:0% +possible uh felt bad and + + + align:start position:0% +possible uh felt bad and +that he missed the chance he felt bad + + align:start position:0% +that he missed the chance he felt bad + + + align:start position:0% +that he missed the chance he felt bad +that he should have + + align:start position:0% +that he should have + + + align:start position:0% +that he should have +shown some compassion at least verbally + + align:start position:0% +shown some compassion at least verbally + + + align:start position:0% +shown some compassion at least verbally +uh + + align:start position:0% +uh + + + align:start position:0% +uh +and + + align:start position:0% +and + + + align:start position:0% +and +uh but the real issue is + + align:start position:0% +uh but the real issue is + + + align:start position:0% +uh but the real issue is +that + + align:start position:0% +that + + + align:start position:0% +that +this test + + align:start position:0% +this test + + + align:start position:0% +this test +was one of his fitness to be the grilled + + align:start position:0% +was one of his fitness to be the grilled + + + align:start position:0% +was one of his fitness to be the grilled +king + + align:start position:0% +king + + + align:start position:0% +king +and the fitness was not measured in + + align:start position:0% +and the fitness was not measured in + + + align:start position:0% +and the fitness was not measured in +terms + + align:start position:0% +terms + + + align:start position:0% +terms +of obedience to the rules the fitness + + align:start position:0% +of obedience to the rules the fitness + + + align:start position:0% +of obedience to the rules the fitness +was measured in terms of leaping quote + + align:start position:0% +was measured in terms of leaping quote + + + align:start position:0% +was measured in terms of leaping quote +important above + + align:start position:0% + + + + align:start position:0% + +uh there's a film called uh + + align:start position:0% + + + + align:start position:0% + +called uh + + align:start position:0% + + + + align:start position:0% + +the cincinnati kid + + align:start position:0% + + + + align:start position:0% + +it's the same theme as uh the hustler + + align:start position:0% +it's the same theme as uh the hustler + + + align:start position:0% +it's the same theme as uh the hustler +except that the hustler was about pooled + + align:start position:0% +except that the hustler was about pooled + + + align:start position:0% +except that the hustler was about pooled +professional food players + + align:start position:0% +professional food players + + + align:start position:0% +professional food players +and uh cincinnati kid was about + + align:start position:0% +and uh cincinnati kid was about + + + align:start position:0% +and uh cincinnati kid was about +professional uh carplay + + align:start position:0% + + + + align:start position:0% + +and the the film ends i'm assuming that + + align:start position:0% +and the the film ends i'm assuming that + + + align:start position:0% +and the the film ends i'm assuming that +y'all are not going to watch the film + + align:start position:0% +y'all are not going to watch the film + + + align:start position:0% +y'all are not going to watch the film +won't be disappointed by me telling you + + align:start position:0% +won't be disappointed by me telling you + + + align:start position:0% +won't be disappointed by me telling you +the ending + + align:start position:0% + + + + align:start position:0% + +no y'all won't watch it because it's in + + align:start position:0% +no y'all won't watch it because it's in + + + align:start position:0% +no y'all won't watch it because it's in +black and white + + align:start position:0% +black and white + + + align:start position:0% +black and white +i think it's a black one maybe + + align:start position:0% +i think it's a black one maybe + + + align:start position:0% +i think it's a black one maybe +maybe color but anyway the film ends + + align:start position:0% +maybe color but anyway the film ends + + + align:start position:0% +maybe color but anyway the film ends +where the main character + + align:start position:0% +where the main character + + + align:start position:0% +where the main character +loses this card game + + align:start position:0% + + + + align:start position:0% + +and he loses it to the old master you + + align:start position:0% +and he loses it to the old master you + + + align:start position:0% +and he loses it to the old master you +beat him up until the very end and he + + align:start position:0% +beat him up until the very end and he + + + align:start position:0% +beat him up until the very end and he +loses all his money and he comes up to + + align:start position:0% +loses all his money and he comes up to + + + align:start position:0% +loses all his money and he comes up to +the master at the end and he says to him + + align:start position:0% +the master at the end and he says to him + + + align:start position:0% +the master at the end and he says to him +says uh + + align:start position:0% + + + + align:start position:0% + +why didn't + + align:start position:0% +why didn't + + + align:start position:0% +why didn't +why did you give up that king + + align:start position:0% +why did you give up that king + + + align:start position:0% +why did you give up that king +not + + align:start position:0% +not + + + align:start position:0% +not +well he said that was uh + + align:start position:0% +well he said that was uh + + + align:start position:0% +well he said that was uh +against all of the rules + + align:start position:0% +against all of the rules + + + align:start position:0% +against all of the rules +of uh probability + + align:start position:0% +of uh probability + + + align:start position:0% +of uh probability +everybody knows it + + align:start position:0% +everybody knows it + + + align:start position:0% +everybody knows it +and the old man said + + align:start position:0% +and the old man said + + + align:start position:0% +and the old man said +the proud the question is not about + + align:start position:0% +the proud the question is not about + + + align:start position:0% +the proud the question is not about +making mistakes the question is about + + align:start position:0% +making mistakes the question is about + + + align:start position:0% +making mistakes the question is about +when to make it + + align:start position:0% + + + + align:start position:0% + +in other words he threw the guy off + + align:start position:0% +in other words he threw the guy off + + + align:start position:0% +in other words he threw the guy off +by throwing away that kid + + align:start position:0% +by throwing away that kid + + + align:start position:0% +by throwing away that kid +uh so um + + align:start position:0% +uh so um + + + align:start position:0% +uh so um +once + + align:start position:0% +once + + + align:start position:0% +once +when the time comes for you to break the + + align:start position:0% +when the time comes for you to break the + + + align:start position:0% +when the time comes for you to break the +rule + + align:start position:0% +rule + + + align:start position:0% +rule +you got to know that the time that this + + align:start position:0% +you got to know that the time that this + + + align:start position:0% +you got to know that the time that this +is the time + + align:start position:0% +is the time + + + align:start position:0% +is the time +and to be prepared to sell the concept + + align:start position:0% +and to be prepared to sell the concept + + + align:start position:0% +and to be prepared to sell the concept +and muscle wasn't willing to do that and + + align:start position:0% +and muscle wasn't willing to do that and + + + align:start position:0% +and muscle wasn't willing to do that and +possible had to mature how long was how + + align:start position:0% +possible had to mature how long was how + + + align:start position:0% +possible had to mature how long was how +many years passed between + + align:start position:0% +many years passed between + + + align:start position:0% +many years passed between +the time that he + + align:start position:0% + + + + align:start position:0% + +missed his chance at the time that he + + align:start position:0% +missed his chance at the time that he + + + align:start position:0% +missed his chance at the time that he +came back and became grail king + + align:start position:0% + + + + align:start position:0% + +and he's looking for this thing all + + align:start position:0% +and he's looking for this thing all + + + align:start position:0% +and he's looking for this thing all +along + + align:start position:0% +along + + + align:start position:0% +along +the castle disappears remember he gets + + align:start position:0% +the castle disappears remember he gets + + + align:start position:0% +the castle disappears remember he gets +up the next morning + + align:start position:0% +up the next morning + + + align:start position:0% +up the next morning +and he hears uh the knights thundering + + align:start position:0% +and he hears uh the knights thundering + + + align:start position:0% +and he hears uh the knights thundering +out of the castle on his way their way + + align:start position:0% +out of the castle on his way their way + + + align:start position:0% +out of the castle on his way their way +someplace and he gets all dressed up and + + align:start position:0% +someplace and he gets all dressed up and + + + align:start position:0% +someplace and he gets all dressed up and +goes out to follow them + + align:start position:0% +goes out to follow them + + + align:start position:0% +goes out to follow them +he can't find them he turns around to go + + align:start position:0% +he can't find them he turns around to go + + + align:start position:0% +he can't find them he turns around to go +back and the castle is gone + + align:start position:0% + + + + align:start position:0% + +and he spends the next x amount of time + + align:start position:0% +and he spends the next x amount of time + + + align:start position:0% +and he spends the next x amount of time +to find go back and find the castle + + align:start position:0% + + + + align:start position:0% + +uh my calculation was 20 years + + align:start position:0% + + + + align:start position:0% + +uh i want you to take some time + + align:start position:0% +uh i want you to take some time + + + align:start position:0% +uh i want you to take some time +if you dispute that + + align:start position:0% +if you dispute that + + + align:start position:0% +if you dispute that +ready + + align:start position:0% +ready + + + align:start position:0% +ready +to give that some thought maybe look + + align:start position:0% +to give that some thought maybe look + + + align:start position:0% +to give that some thought maybe look +through the book a little bit more + + align:start position:0% +through the book a little bit more + + + align:start position:0% +through the book a little bit more +he was out there for quite a while + + align:start position:0% + + + + align:start position:0% + +and after he has all of these exploits + + align:start position:0% +and after he has all of these exploits + + + align:start position:0% +and after he has all of these exploits +then he has proved himself worthy + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +um + + align:start position:0% + + + + align:start position:0% + +just + + align:start position:0% + + + + align:start position:0% + +they never say exactly + + align:start position:0% +they never say exactly + + + align:start position:0% +they never say exactly +and i didn't want to go get one of the + + align:start position:0% +and i didn't want to go get one of the + + + align:start position:0% +and i didn't want to go get one of the +cliff notes or anything like that to + + align:start position:0% +cliff notes or anything like that to + + + align:start position:0% +cliff notes or anything like that to +look it up i just did not want to do + + align:start position:0% +look it up i just did not want to do + + + align:start position:0% +look it up i just did not want to do +that + + align:start position:0% +that + + + align:start position:0% +that +and so i went back and started reading + + align:start position:0% +and so i went back and started reading + + + align:start position:0% +and so i went back and started reading +and taking little pieces + + align:start position:0% +and taking little pieces + + + align:start position:0% +and taking little pieces +and my account like i said + + align:start position:0% +and my account like i said + + + align:start position:0% +and my account like i said +there is a good answer to that if you go + + align:start position:0% +there is a good answer to that if you go + + + align:start position:0% +there is a good answer to that if you go +to the humanities + + align:start position:0% +to the humanities + + + align:start position:0% +to the humanities +department they'll all know the number + + align:start position:0% +department they'll all know the number + + + align:start position:0% +department they'll all know the number +all right but i didn't want to do it i + + align:start position:0% +all right but i didn't want to do it i + + + align:start position:0% +all right but i didn't want to do it i +wanted to have fun doing it on my own + + align:start position:0% +wanted to have fun doing it on my own + + + align:start position:0% +wanted to have fun doing it on my own +and i want to leave that to you all + + align:start position:0% +and i want to leave that to you all + + + align:start position:0% +and i want to leave that to you all +but my calculation was 20 years + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% + + + + align:start position:0% + +oh i should have + + align:start position:0% +oh i should have + + + align:start position:0% +oh i should have +i feel so awful i should have asked him + + align:start position:0% +i feel so awful i should have asked him + + + align:start position:0% +i feel so awful i should have asked him +about his illness i feel that i need to + + align:start position:0% +about his illness i feel that i need to + + + align:start position:0% +about his illness i feel that i need to +go back like other people told him that + + align:start position:0% +go back like other people told him that + + + align:start position:0% +go back like other people told him that +he messed up + + align:start position:0% +he messed up + + + align:start position:0% +he messed up +which is + + align:start position:0% +which is + + + align:start position:0% +which is +an interesting + + align:start position:0% + + + + align:start position:0% + +take on sort + + align:start position:0% + + + + align:start position:0% + +yeah uh now this is another uh trait + + align:start position:0% +yeah uh now this is another uh trait + + + align:start position:0% +yeah uh now this is another uh trait +of uh many uh mythic heroes + + align:start position:0% +of uh many uh mythic heroes + + + align:start position:0% +of uh many uh mythic heroes +uh and that is + + align:start position:0% + + + + align:start position:0% + +they all have at least one + + align:start position:0% +they all have at least one + + + align:start position:0% +they all have at least one +fatal + + align:start position:0% +fatal + + + align:start position:0% +fatal +character flaw + + align:start position:0% +character flaw + + + align:start position:0% +character flaw +fatal + + align:start position:0% +fatal + + + align:start position:0% +fatal +if you read oedipus + + align:start position:0% +if you read oedipus + + + align:start position:0% +if you read oedipus +you go back to the trojan wars + + align:start position:0% +you go back to the trojan wars + + + align:start position:0% +you go back to the trojan wars +no matter who they are they all have + + align:start position:0% +no matter who they are they all have + + + align:start position:0% +no matter who they are they all have +some + + align:start position:0% +some + + + align:start position:0% +some +very + + align:start position:0% +very + + + align:start position:0% +very +bad + + align:start position:0% +bad + + + align:start position:0% +bad +bad is not the word fatal is the word + + align:start position:0% +bad is not the word fatal is the word + + + align:start position:0% +bad is not the word fatal is the word +uh even if it doesn't kill them it kills + + align:start position:0% +uh even if it doesn't kill them it kills + + + align:start position:0% +uh even if it doesn't kill them it kills +their careers it does all of these + + align:start position:0% +their careers it does all of these + + + align:start position:0% +their careers it does all of these +terrible things + + align:start position:0% +terrible things + + + align:start position:0% +terrible things +uh and and + + align:start position:0% +uh and and + + + align:start position:0% +uh and and +does that is there a lesson in all of + + align:start position:0% +does that is there a lesson in all of + + + align:start position:0% +does that is there a lesson in all of +that + + align:start position:0% + + + + align:start position:0% + +well i think one lesson is that if + + align:start position:0% +well i think one lesson is that if + + + align:start position:0% +well i think one lesson is that if +you're going to look for somebody to + + align:start position:0% +you're going to look for somebody to + + + align:start position:0% +you're going to look for somebody to +pattern + + align:start position:0% +pattern + + + align:start position:0% +pattern +your life after in any way + + align:start position:0% +your life after in any way + + + align:start position:0% +your life after in any way +in any particular way or if you're going + + align:start position:0% +in any particular way or if you're going + + + align:start position:0% +in any particular way or if you're going +to advise your children + + align:start position:0% +to advise your children + + + align:start position:0% +to advise your children +to be like somebody else + + align:start position:0% +to be like somebody else + + + align:start position:0% +to be like somebody else +you're not going to find anybody that's + + align:start position:0% +you're not going to find anybody that's + + + align:start position:0% +you're not going to find anybody that's +perfect + + align:start position:0% + + + + align:start position:0% + +unless you've got a religious bent but + + align:start position:0% +unless you've got a religious bent but + + + align:start position:0% +unless you've got a religious bent but +uh you know you're gonna find people who + + align:start position:0% +uh you know you're gonna find people who + + + align:start position:0% +uh you know you're gonna find people who +make mistakes + + align:start position:0% +make mistakes + + + align:start position:0% +make mistakes +and the heroes at least all of the ones + + align:start position:0% +and the heroes at least all of the ones + + + align:start position:0% +and the heroes at least all of the ones +that i have read + + align:start position:0% +that i have read + + + align:start position:0% +that i have read +are the ones who not only do great deeds + + align:start position:0% +are the ones who not only do great deeds + + + align:start position:0% +are the ones who not only do great deeds +but make big mistakes i mean when they + + align:start position:0% +but make big mistakes i mean when they + + + align:start position:0% +but make big mistakes i mean when they +make a mistake + + align:start position:0% +make a mistake + + + align:start position:0% +make a mistake +it is + + align:start position:0% +it is + + + align:start position:0% +it is +big + + align:start position:0% +big + + + align:start position:0% +big +terrible to them terrible to everybody + + align:start position:0% +terrible to them terrible to everybody + + + align:start position:0% +terrible to them terrible to everybody +around + + align:start position:0% +around + + + align:start position:0% +around +uh + + align:start position:0% +uh + + + align:start position:0% +uh +and i think that's the way it is if you + + align:start position:0% +and i think that's the way it is if you + + + align:start position:0% +and i think that's the way it is if you +play in the if you play in the big game + + align:start position:0% +play in the if you play in the big game + + + align:start position:0% +play in the if you play in the big game +you make big mistakes you make big gains + + align:start position:0% +you make big mistakes you make big gains + + + align:start position:0% +you make big mistakes you make big gains +when you make them but you make big + + align:start position:0% +when you make them but you make big + + + align:start position:0% +when you make them but you make big +mistakes too + + align:start position:0% +mistakes too + + + align:start position:0% +mistakes too +um + + align:start position:0% + + + + align:start position:0% + +yeah let's talk about his character some + + align:start position:0% +yeah let's talk about his character some + + + align:start position:0% +yeah let's talk about his character some +more what about was did he did his + + align:start position:0% +more what about was did he did his + + + align:start position:0% +more what about was did he did his +character change as he got older + + align:start position:0% +character change as he got older + + + align:start position:0% +character change as he got older +yeah i think he did + + align:start position:0% +yeah i think he did + + + align:start position:0% +yeah i think he did +i mean + + align:start position:0% + + + + align:start position:0% + +frustrates me the way he became a knight + + align:start position:0% +frustrates me the way he became a knight + + + align:start position:0% +frustrates me the way he became a knight +was by killing another knight in order + + align:start position:0% +was by killing another knight in order + + + align:start position:0% +was by killing another knight in order +to get his clothing yeah + + align:start position:0% +to get his clothing yeah + + + align:start position:0% +to get his clothing yeah +and + + align:start position:0% +and + + + align:start position:0% +and +i know that + + align:start position:0% +i know that + + + align:start position:0% +i know that +the + + align:start position:0% +the + + + align:start position:0% +the +trajectory in the book is that he is + + align:start position:0% +trajectory in the book is that he is + + + align:start position:0% +trajectory in the book is that he is +he's foolish he's young he doesn't know + + align:start position:0% +he's foolish he's young he doesn't know + + + align:start position:0% +he's foolish he's young he doesn't know +about knighthood + + align:start position:0% +about knighthood + + + align:start position:0% +about knighthood +he thinks he needs all the night to get + + align:start position:0% +he thinks he needs all the night to get + + + align:start position:0% +he thinks he needs all the night to get +close and then he matures + + align:start position:0% +close and then he matures + + + align:start position:0% +close and then he matures +but + + align:start position:0% + + + + align:start position:0% + +but the author doesn't like that + + align:start position:0% +but the author doesn't like that + + + align:start position:0% +but the author doesn't like that +murder ought to be + + align:start position:0% +murder ought to be + + + align:start position:0% +murder ought to be +the major flaw + + align:start position:0% +the major flaw + + + align:start position:0% +the major flaw +no the major + + align:start position:0% + + + + align:start position:0% + +it wasn't a heroic + + align:start position:0% + + + + align:start position:0% + +no + + align:start position:0% +no + + + align:start position:0% +no +i wouldn't call that heroic uh + + align:start position:0% + + + + align:start position:0% + +because there was nobody nobody else no + + align:start position:0% +because there was nobody nobody else no + + + align:start position:0% +because there was nobody nobody else no +one else's interest at stake + + align:start position:0% +one else's interest at stake + + + align:start position:0% +one else's interest at stake +that he was protecting + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% +um + + + align:start position:0% +um +there's a scene i'm trying to think of + + align:start position:0% +there's a scene i'm trying to think of + + + align:start position:0% +there's a scene i'm trying to think of +it uh in the film is one of my one of my + + align:start position:0% +it uh in the film is one of my one of my + + + align:start position:0% +it uh in the film is one of my one of my +favorite films um + + align:start position:0% +favorite films um + + + align:start position:0% +favorite films um +trying to think of what i think it was + + align:start position:0% +trying to think of what i think it was + + + align:start position:0% +trying to think of what i think it was +robert + + align:start position:0% +robert + + + align:start position:0% +robert +one of robin one of the robin hood + + align:start position:0% +one of robin one of the robin hood + + + align:start position:0% +one of robin one of the robin hood +movies + + align:start position:0% +movies + + + align:start position:0% +movies +where robin hood gets into the sword + + align:start position:0% +where robin hood gets into the sword + + + align:start position:0% +where robin hood gets into the sword +fight + + align:start position:0% +fight + + + align:start position:0% +fight +with his knight and he doesn't know it's + + align:start position:0% +with his knight and he doesn't know it's + + + align:start position:0% +with his knight and he doesn't know it's +a + + align:start position:0% +a + + + align:start position:0% +a +it's uh + + align:start position:0% +it's uh + + + align:start position:0% +it's uh +richard + + align:start position:0% + + + + align:start position:0% + +and they're fighting + + align:start position:0% +and they're fighting + + + align:start position:0% +and they're fighting +and richard goes with a lunge + + align:start position:0% +and richard goes with a lunge + + + align:start position:0% +and richard goes with a lunge +and robin hood steps out of the way and + + align:start position:0% +and robin hood steps out of the way and + + + align:start position:0% +and robin hood steps out of the way and +richard gets his + + align:start position:0% +richard gets his + + + align:start position:0% +richard gets his +sword + + align:start position:0% +sword + + + align:start position:0% +sword +stuck into a tree + + align:start position:0% +stuck into a tree + + + align:start position:0% +stuck into a tree +now they're fighting to the death this + + align:start position:0% +now they're fighting to the death this + + + align:start position:0% +now they're fighting to the death this +is serious + + align:start position:0% +is serious + + + align:start position:0% +is serious +and + + align:start position:0% +and + + + align:start position:0% +and +robin hood i think it is puts down his + + align:start position:0% +robin hood i think it is puts down his + + + align:start position:0% +robin hood i think it is puts down his +sword and goes helps him pull it out of + + align:start position:0% +sword and goes helps him pull it out of + + + align:start position:0% +sword and goes helps him pull it out of +the tree + + align:start position:0% +the tree + + + align:start position:0% +the tree +he got an opportunity to stab the man in + + align:start position:0% +he got an opportunity to stab the man in + + + align:start position:0% +he got an opportunity to stab the man in +the back but chivalry says + + align:start position:0% +the back but chivalry says + + + align:start position:0% +the back but chivalry says +you don't do that all right + + align:start position:0% +you don't do that all right + + + align:start position:0% +you don't do that all right +so uh they got this these rules of + + align:start position:0% +so uh they got this these rules of + + + align:start position:0% +so uh they got this these rules of +chivalry + + align:start position:0% +chivalry + + + align:start position:0% +chivalry +will i think they i think if you follow + + align:start position:0% +will i think they i think if you follow + + + align:start position:0% +will i think they i think if you follow +the rules of chivalry there's something + + align:start position:0% +the rules of chivalry there's something + + + align:start position:0% +the rules of chivalry there's something +about it that's + + align:start position:0% +about it that's + + + align:start position:0% +about it that's +that is hero making in it + + align:start position:0% +that is hero making in it + + + align:start position:0% +that is hero making in it +it helps you get there + + align:start position:0% +it helps you get there + + + align:start position:0% +it helps you get there +uh i don't think those are heroic deeds + + align:start position:0% +uh i don't think those are heroic deeds + + + align:start position:0% +uh i don't think those are heroic deeds +but it sort of gets you into a mindset + + align:start position:0% +but it sort of gets you into a mindset + + + align:start position:0% +but it sort of gets you into a mindset +that there's something that's higher + + align:start position:0% +that there's something that's higher + + + align:start position:0% +that there's something that's higher +than you + + align:start position:0% +than you + + + align:start position:0% +than you +and uh that you i mean if a man + + align:start position:0% +and uh that you i mean if a man + + + align:start position:0% +and uh that you i mean if a man +if you're gonna kill a man you don't + + align:start position:0% +if you're gonna kill a man you don't + + + align:start position:0% +if you're gonna kill a man you don't +kill him by stabbing him in the back or + + align:start position:0% +kill him by stabbing him in the back or + + + align:start position:0% +kill him by stabbing him in the back or +certain kind of things you just don't do + + align:start position:0% +certain kind of things you just don't do + + + align:start position:0% +certain kind of things you just don't do +these + + align:start position:0% + + + + align:start position:0% + +what about his half brother + + align:start position:0% + + + + align:start position:0% + +you see any point to + + align:start position:0% +you see any point to + + + align:start position:0% +you see any point to +the story of him and his half brother + + align:start position:0% + + + + align:start position:0% + +fear fees that's the best pronunciation + + align:start position:0% +fear fees that's the best pronunciation + + + align:start position:0% +fear fees that's the best pronunciation +i can get out of it + + align:start position:0% + + + + align:start position:0% + +well he + + align:start position:0% +well he + + + align:start position:0% +well he +certainly + + align:start position:0% +certainly + + + align:start position:0% +certainly +seems essential + + align:start position:0% +seems essential + + + align:start position:0% +seems essential +to parcel + + align:start position:0% +to parcel + + + align:start position:0% +to parcel +eventual saving of the + + align:start position:0% +eventual saving of the + + + align:start position:0% +eventual saving of the +castle + + align:start position:0% + + + + align:start position:0% + +and you could probably argue that if he + + align:start position:0% +and you could probably argue that if he + + + align:start position:0% +and you could probably argue that if he +hadn't met up with + + align:start position:0% + + + + align:start position:0% + +why do you think the author + + align:start position:0% +why do you think the author + + + align:start position:0% +why do you think the author +made this bizarre + + align:start position:0% +made this bizarre + + + align:start position:0% +made this bizarre +uh characterization of fear fears + + align:start position:0% +uh characterization of fear fears + + + align:start position:0% +uh characterization of fear fears +as being + + align:start position:0% +as being + + + align:start position:0% +as being +patched black like + + align:start position:0% + + + + align:start position:0% + +like a like like a pinto horse + + align:start position:0% + + + + align:start position:0% + +why would an author just + + align:start position:0% +why would an author just + + + align:start position:0% +why would an author just +do that uh is there is there any connect + + align:start position:0% +do that uh is there is there any connect + + + align:start position:0% +do that uh is there is there any connect +i mean + + align:start position:0% +i mean + + + align:start position:0% +i mean +why would an author do that that was not + + align:start position:0% +why would an author do that that was not + + + align:start position:0% +why would an author do that that was not +uh + + align:start position:0% +uh + + + align:start position:0% +uh +the ligo i think why would author do + + align:start position:0% +the ligo i think why would author do + + + align:start position:0% +the ligo i think why would author do +that + + align:start position:0% + + + + align:start position:0% + +well i tell you what i think well i'll + + align:start position:0% +well i tell you what i think well i'll + + + align:start position:0% +well i tell you what i think well i'll +tell you what joseph campbell says + + align:start position:0% +tell you what joseph campbell says + + + align:start position:0% +tell you what joseph campbell says +and then i'll tell you what i think + + align:start position:0% +and then i'll tell you what i think + + + align:start position:0% +and then i'll tell you what i think +which is almost the same thing + + align:start position:0% + + + + align:start position:0% + +this author + + align:start position:0% + + + + align:start position:0% + +wants to reconcile + + align:start position:0% +wants to reconcile + + + align:start position:0% +wants to reconcile +the humans pagans + + align:start position:0% + + + + align:start position:0% + +and the only thing that's going to + + align:start position:0% +and the only thing that's going to + + + align:start position:0% +and the only thing that's going to +impress possible in terms of + + align:start position:0% +impress possible in terms of + + + align:start position:0% +impress possible in terms of +reconciliation is kinship + + align:start position:0% +reconciliation is kinship + + + align:start position:0% +reconciliation is kinship +so i think what he's trying to say is + + align:start position:0% +so i think what he's trying to say is + + + align:start position:0% +so i think what he's trying to say is +that fearful fear fees is half black + + align:start position:0% +that fearful fear fees is half black + + + align:start position:0% +that fearful fear fees is half black +half white + + align:start position:0% +half white + + + align:start position:0% +half white +she was + + align:start position:0% + + + + align:start position:0% + +but the key issue was + + align:start position:0% +but the key issue was + + + align:start position:0% +but the key issue was +pagan versus christian + + align:start position:0% +pagan versus christian + + + align:start position:0% +pagan versus christian +and that the two of them became the best + + align:start position:0% +and that the two of them became the best + + + align:start position:0% +and that the two of them became the best +of friends at the end + + align:start position:0% + + + + align:start position:0% + +so i think the author was trying to say + + align:start position:0% +so i think the author was trying to say + + + align:start position:0% +so i think the author was trying to say +that um + + align:start position:0% +that um + + + align:start position:0% +that um +this these are the uh + + align:start position:0% +this these are the uh + + + align:start position:0% +this these are the uh +early middle ages and the dark ages + + align:start position:0% +early middle ages and the dark ages + + + align:start position:0% +early middle ages and the dark ages +that + + align:start position:0% +that + + + align:start position:0% +that +all of this all of this hatred + + align:start position:0% +all of this all of this hatred + + + align:start position:0% +all of this all of this hatred +between christians pagans gotta go + + align:start position:0% + + + + align:start position:0% + +and he tries to do it in the most + + align:start position:0% +and he tries to do it in the most + + + align:start position:0% +and he tries to do it in the most +compelling way to somebody like possible + + align:start position:0% +compelling way to somebody like possible + + + align:start position:0% +compelling way to somebody like possible +make it part + + align:start position:0% + + + + align:start position:0% + +but it's interesting that + + align:start position:0% +but it's interesting that + + + align:start position:0% +but it's interesting that +oh yeah so carsonville accepted fear of + + align:start position:0% +oh yeah so carsonville accepted fear of + + + align:start position:0% +oh yeah so carsonville accepted fear of +views as he was black + + align:start position:0% + + + + align:start position:0% + +and practice + + align:start position:0% + + + + align:start position:0% + +but in the end + + align:start position:0% + + + + align:start position:0% + +we'll have the wife that he wanted + + align:start position:0% +we'll have the wife that he wanted + + + align:start position:0% +we'll have the wife that he wanted +to leave the life that he wanted he had + + align:start position:0% +to leave the life that he wanted he had + + + align:start position:0% +to leave the life that he wanted he had +to be baptized + + align:start position:0% +to be baptized + + + align:start position:0% +to be baptized +that's right he still had to be baptized + + align:start position:0% + + + + align:start position:0% + +well uh let's uh + + align:start position:0% +well uh let's uh + + + align:start position:0% +well uh let's uh +dig into that one um + + align:start position:0% + + + + align:start position:0% + +at the time + + align:start position:0% +at the time + + + align:start position:0% +at the time +civilizations were created around the + + align:start position:0% +civilizations were created around the + + + align:start position:0% +civilizations were created around the +world + + align:start position:0% +world + + + align:start position:0% +world +uh independently of one another + + align:start position:0% + + + + align:start position:0% + +uh + + align:start position:0% + + + + align:start position:0% + +it was motivated by two things number + + align:start position:0% +it was motivated by two things number + + + align:start position:0% +it was motivated by two things number +one what was motivated by the weather + + align:start position:0% +one what was motivated by the weather + + + align:start position:0% +one what was motivated by the weather +yeah i mean it was a time when + + align:start position:0% +yeah i mean it was a time when + + + align:start position:0% +yeah i mean it was a time when +there were these grasses + + align:start position:0% +there were these grasses + + + align:start position:0% +there were these grasses +in that could that could sustain hip a + + align:start position:0% +in that could that could sustain hip a + + + align:start position:0% +in that could that could sustain hip a +large populations + + align:start position:0% +large populations + + + align:start position:0% +large populations +uh + + align:start position:0% +uh + + + align:start position:0% +uh +and + + align:start position:0% +and + + + align:start position:0% +and +we have the uh wheat + + align:start position:0% +we have the uh wheat + + + align:start position:0% +we have the uh wheat +cultures in the middle east the rice + + align:start position:0% +cultures in the middle east the rice + + + align:start position:0% +cultures in the middle east the rice +cultures in the east the corn + + align:start position:0% +cultures in the east the corn + + + align:start position:0% +cultures in the east the corn +cultures in the uh + + align:start position:0% +cultures in the uh + + + align:start position:0% +cultures in the uh +western uh + + align:start position:0% +western uh + + + align:start position:0% +western uh +in the americas the western americas + + align:start position:0% +in the americas the western americas + + + align:start position:0% +in the americas the western americas +they could sustain large cultures and + + align:start position:0% +they could sustain large cultures and + + + align:start position:0% +they could sustain large cultures and +the cultures did not have to be nomadic + + align:start position:0% +the cultures did not have to be nomadic + + + align:start position:0% +the cultures did not have to be nomadic +or semi-nomadic they could stay in one + + align:start position:0% +or semi-nomadic they could stay in one + + + align:start position:0% +or semi-nomadic they could stay in one +place + + align:start position:0% +place + + + align:start position:0% +place +the other thing was around that time was + + align:start position:0% +the other thing was around that time was + + + align:start position:0% +the other thing was around that time was +that human beings + + align:start position:0% +that human beings + + + align:start position:0% +that human beings +had figured out + + align:start position:0% +had figured out + + + align:start position:0% +had figured out +how to herd animals + + align:start position:0% + + + + align:start position:0% + +so instead of going out hoping you see + + align:start position:0% +so instead of going out hoping you see + + + align:start position:0% +so instead of going out hoping you see +one one day and + + align:start position:0% +one one day and + + + align:start position:0% +one one day and +killing it and hoping it doesn't kill + + align:start position:0% +killing it and hoping it doesn't kill + + + align:start position:0% +killing it and hoping it doesn't kill +you + + align:start position:0% +you + + + align:start position:0% +you +you can just + + align:start position:0% +you can just + + + align:start position:0% +you can just +herd the animals right along and take + + align:start position:0% +herd the animals right along and take + + + align:start position:0% +herd the animals right along and take +one whenever you get ready + + align:start position:0% + + + + align:start position:0% + +so you have two kinds of cultures you + + align:start position:0% +so you have two kinds of cultures you + + + align:start position:0% +so you have two kinds of cultures you +have + + align:start position:0% +have + + + align:start position:0% +have +the herding culture and you have + + align:start position:0% +the herding culture and you have + + + align:start position:0% +the herding culture and you have +the agrarian culture + + align:start position:0% +the agrarian culture + + + align:start position:0% +the agrarian culture +the herding is still moving around the + + align:start position:0% +the herding is still moving around the + + + align:start position:0% +the herding is still moving around the +agrarian is sept + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +um + + align:start position:0% + + + + align:start position:0% + +the + + align:start position:0% +the + + + align:start position:0% +the +herding cultures + + align:start position:0% +herding cultures + + + align:start position:0% +herding cultures +are kinship societies + + align:start position:0% + + + + align:start position:0% + +civilization was made up by different + + align:start position:0% +civilization was made up by different + + + align:start position:0% +civilization was made up by different +kinship groups it was a multicultural + + align:start position:0% +kinship groups it was a multicultural + + + align:start position:0% +kinship groups it was a multicultural +society + + align:start position:0% + + + + align:start position:0% + +so the rules of social order + + align:start position:0% + + + + align:start position:0% + +for a uh for civilization + + align:start position:0% + + + + align:start position:0% + +were more strict or stricter + + align:start position:0% +were more strict or stricter + + + align:start position:0% +were more strict or stricter +or more or + + align:start position:0% +or more or + + + align:start position:0% +or more or +social order was more problematic for + + align:start position:0% +social order was more problematic for + + + align:start position:0% +social order was more problematic for +cultures + + align:start position:0% +cultures + + + align:start position:0% +cultures +for for for civilized cultures than it + + align:start position:0% +for for for civilized cultures than it + + + align:start position:0% +for for for civilized cultures than it +was for + + align:start position:0% +was for + + + align:start position:0% +was for +nomadic + + align:start position:0% +nomadic + + + align:start position:0% +nomadic +hurting cultures because all you did was + + align:start position:0% +hurting cultures because all you did was + + + align:start position:0% +hurting cultures because all you did was +obey your father and your father obeyed + + align:start position:0% +obey your father and your father obeyed + + + align:start position:0% +obey your father and your father obeyed +his grant your grandfather + + align:start position:0% +his grant your grandfather + + + align:start position:0% +his grant your grandfather +you obeyed your mother + + align:start position:0% +you obeyed your mother + + + align:start position:0% +you obeyed your mother +your mother obeyed her grandmother + + align:start position:0% +your mother obeyed her grandmother + + + align:start position:0% +your mother obeyed her grandmother +but when you've got different families + + align:start position:0% +but when you've got different families + + + align:start position:0% +but when you've got different families +in living in the same place how do you + + align:start position:0% +in living in the same place how do you + + + align:start position:0% +in living in the same place how do you +keep them in order + + align:start position:0% +keep them in order + + + align:start position:0% +keep them in order +all right + + align:start position:0% +all right + + + align:start position:0% +all right +and uh here's how they did it + + align:start position:0% +and uh here's how they did it + + + align:start position:0% +and uh here's how they did it +religion + + align:start position:0% + + + + align:start position:0% + +so they they invented great priesthoods + + align:start position:0% +so they they invented great priesthoods + + + align:start position:0% +so they they invented great priesthoods +and the great priesthoods + + align:start position:0% +and the great priesthoods + + + align:start position:0% +and the great priesthoods +uh found it increasingly difficult to + + align:start position:0% +uh found it increasingly difficult to + + + align:start position:0% +uh found it increasingly difficult to +keep the social order + + align:start position:0% +keep the social order + + + align:start position:0% +keep the social order +so what they did was they had to find + + align:start position:0% +so what they did was they had to find + + + align:start position:0% +so what they did was they had to find +ways of keeping people anchored + + align:start position:0% +ways of keeping people anchored + + + align:start position:0% +ways of keeping people anchored +to + + align:start position:0% +to + + + align:start position:0% +to +to an idea + + align:start position:0% +to an idea + + + align:start position:0% +to an idea +that was compelling on them + + align:start position:0% +that was compelling on them + + + align:start position:0% +that was compelling on them +and the shaman + + align:start position:0% +and the shaman + + + align:start position:0% +and the shaman +with talk with with uh his um + + align:start position:0% +with talk with with uh his um + + + align:start position:0% +with talk with with uh his um +insights in the unconscious + + align:start position:0% +insights in the unconscious + + + align:start position:0% +insights in the unconscious +uh + + align:start position:0% +uh + + + align:start position:0% +uh +just became + + align:start position:0% +just became + + + align:start position:0% +just became +not very compelling any longer + + align:start position:0% +not very compelling any longer + + + align:start position:0% +not very compelling any longer +because people did not share the same + + align:start position:0% +because people did not share the same + + + align:start position:0% +because people did not share the same +unconscious + + align:start position:0% +unconscious + + + align:start position:0% +unconscious +they were different from different + + align:start position:0% +they were different from different + + + align:start position:0% +they were different from different +groups different families + + align:start position:0% +groups different families + + + align:start position:0% +groups different families +so what happened in the end was + + align:start position:0% +so what happened in the end was + + + align:start position:0% +so what happened in the end was +that um + + align:start position:0% +that um + + + align:start position:0% +that um +the + + align:start position:0% +the + + + align:start position:0% +the +priesthood developed + + align:start position:0% +priesthood developed + + + align:start position:0% +priesthood developed +probably not out of the shamans + + align:start position:0% + + + + align:start position:0% + +because a shaman has a personality + + align:start position:0% +because a shaman has a personality + + + align:start position:0% +because a shaman has a personality +that requires a discussion + + align:start position:0% +that requires a discussion + + + align:start position:0% +that requires a discussion +so i don't see + + align:start position:0% +so i don't see + + + align:start position:0% +so i don't see +three or four shaman getting down and + + align:start position:0% +three or four shaman getting down and + + + align:start position:0% +three or four shaman getting down and +saying let's start a priest + + align:start position:0% +saying let's start a priest + + + align:start position:0% +saying let's start a priest +uh and work together and in a hierarchy + + align:start position:0% +uh and work together and in a hierarchy + + + align:start position:0% +uh and work together and in a hierarchy +i don't see that + + align:start position:0% +i don't see that + + + align:start position:0% +i don't see that +um + + align:start position:0% +um + + + align:start position:0% +um +a shaman becomes a shaman by way of + + align:start position:0% +a shaman becomes a shaman by way of + + + align:start position:0% +a shaman becomes a shaman by way of +having + + align:start position:0% +having + + + align:start position:0% +having +i hope you all can tolerate some of + + align:start position:0% +i hope you all can tolerate some of + + + align:start position:0% +i hope you all can tolerate some of +these diversions because it's just too + + align:start position:0% +these diversions because it's just too + + + align:start position:0% +these diversions because it's just too +interesting + + align:start position:0% +interesting + + + align:start position:0% +interesting +a shaman becomes a shaman by virtue of + + align:start position:0% +a shaman becomes a shaman by virtue of + + + align:start position:0% +a shaman becomes a shaman by virtue of +having had + + align:start position:0% +having had + + + align:start position:0% +having had +a traumatic experience in childhood + + align:start position:0% +a traumatic experience in childhood + + + align:start position:0% +a traumatic experience in childhood +i'm sorry + + align:start position:0% +i'm sorry + + + align:start position:0% +i'm sorry +the word + + align:start position:0% +the word + + + align:start position:0% +the word +describes a witch duck okay + + align:start position:0% +describes a witch duck okay + + + align:start position:0% +describes a witch duck okay +in very early prehistorics yes + + align:start position:0% +in very early prehistorics yes + + + align:start position:0% +in very early prehistorics yes +yes + + align:start position:0% +yes + + + align:start position:0% +yes +uh + + align:start position:0% +uh + + + align:start position:0% +uh +but you can find people who do not have + + align:start position:0% +but you can find people who do not have + + + align:start position:0% +but you can find people who do not have +the function of ashaming + + align:start position:0% +the function of ashaming + + + align:start position:0% +the function of ashaming +in society today + + align:start position:0% +in society today + + + align:start position:0% +in society today +uh one one + + align:start position:0% +uh one one + + + align:start position:0% +uh one one +a very good example of a of a person who + + align:start position:0% +a very good example of a of a person who + + + align:start position:0% +a very good example of a of a person who +has the same personality + + align:start position:0% +has the same personality + + + align:start position:0% +has the same personality +uh as a shaman uh is this mathematician + + align:start position:0% +uh as a shaman uh is this mathematician + + + align:start position:0% +uh as a shaman uh is this mathematician +named ramanujan + + align:start position:0% + + + + align:start position:0% + +he's an indian + + align:start position:0% +he's an indian + + + align:start position:0% +he's an indian +and the story is that + + align:start position:0% +and the story is that + + + align:start position:0% +and the story is that +when he was a child his parents would + + align:start position:0% +when he was a child his parents would + + + align:start position:0% +when he was a child his parents would +get into these + + align:start position:0% +get into these + + + align:start position:0% +get into these +violent arguments + + align:start position:0% +violent arguments + + + align:start position:0% +violent arguments +and he would crawl under the bed + + align:start position:0% +and he would crawl under the bed + + + align:start position:0% +and he would crawl under the bed +with a pencil and paper and try to do + + align:start position:0% +with a pencil and paper and try to do + + + align:start position:0% +with a pencil and paper and try to do +math problems to keep it out of his head + + align:start position:0% + + + + align:start position:0% + +uh what happened in the end was that he + + align:start position:0% +uh what happened in the end was that he + + + align:start position:0% +uh what happened in the end was that he +became a very great + + align:start position:0% +became a very great + + + align:start position:0% +became a very great +mathematician but they called him an + + align:start position:0% +mathematician but they called him an + + + align:start position:0% +mathematician but they called him an +intuitive mathematician he could not + + align:start position:0% +intuitive mathematician he could not + + + align:start position:0% +intuitive mathematician he could not +prove to you any of his + + align:start position:0% +prove to you any of his + + + align:start position:0% +prove to you any of his +results but his results worked one of + + align:start position:0% +results but his results worked one of + + + align:start position:0% +results but his results worked one of +the things he did was uh + + align:start position:0% +the things he did was uh + + + align:start position:0% +the things he did was uh +now here's something for you to look up + + align:start position:0% +now here's something for you to look up + + + align:start position:0% +now here's something for you to look up +in the details i'm just i'm going to + + align:start position:0% +in the details i'm just i'm going to + + + align:start position:0% +in the details i'm just i'm going to +recite from memory + + align:start position:0% +recite from memory + + + align:start position:0% +recite from memory +ramanujan + + align:start position:0% +ramanujan + + + align:start position:0% +ramanujan +found a way + + align:start position:0% +found a way + + + align:start position:0% +found a way +to discern + + align:start position:0% +to discern + + + align:start position:0% +to discern +whether + + align:start position:0% +whether + + + align:start position:0% +whether +a 20-digit number + + align:start position:0% +a 20-digit number + + + align:start position:0% +a 20-digit number +was a prime number or not + + align:start position:0% +was a prime number or not + + + align:start position:0% +was a prime number or not +and he figured it out + + align:start position:0% +and he figured it out + + + align:start position:0% +and he figured it out +by hand i mean there's a hand method + + align:start position:0% +by hand i mean there's a hand method + + + align:start position:0% +by hand i mean there's a hand method +where you could figure out + + align:start position:0% +where you could figure out + + + align:start position:0% +where you could figure out +uh whether it's prime or not + + align:start position:0% +uh whether it's prime or not + + + align:start position:0% +uh whether it's prime or not +uh and + + align:start position:0% +uh and + + + align:start position:0% +uh and +um somebody + + align:start position:0% +um somebody + + + align:start position:0% +um somebody +use that method + + align:start position:0% +use that method + + + align:start position:0% +use that method +uh to to um + + align:start position:0% +uh to to um + + + align:start position:0% +uh to to um +frustrate the us military + + align:start position:0% +frustrate the us military + + + align:start position:0% +frustrate the us military +because + + align:start position:0% + + + + align:start position:0% + +uh the military uh + + align:start position:0% +uh the military uh + + + align:start position:0% +uh the military uh +had its + + align:start position:0% +had its + + + align:start position:0% +had its +um icbms is intercontinental with this + + align:start position:0% +um icbms is intercontinental with this + + + align:start position:0% +um icbms is intercontinental with this +ballistic missiles + + align:start position:0% +ballistic missiles + + + align:start position:0% +ballistic missiles +um + + align:start position:0% +um + + + align:start position:0% +um +their orders were coded in prime numbers + + align:start position:0% + + + + align:start position:0% + +you can break the code by at hand the + + align:start position:0% +you can break the code by at hand the + + + align:start position:0% +you can break the code by at hand the +idea is you could still break the code + + align:start position:0% +idea is you could still break the code + + + align:start position:0% +idea is you could still break the code +by a computer but you'd have to run a + + align:start position:0% +by a computer but you'd have to run a + + + align:start position:0% +by a computer but you'd have to run a +computer + + align:start position:0% +computer + + + align:start position:0% +computer +for a month + + align:start position:0% +for a month + + + align:start position:0% +for a month +by that time they would change + + align:start position:0% +by that time they would change + + + align:start position:0% +by that time they would change +the codes + + align:start position:0% +the codes + + + align:start position:0% +the codes +well if you could come in and do it by + + align:start position:0% +well if you could come in and do it by + + + align:start position:0% +well if you could come in and do it by +hand you could knock it down they said + + align:start position:0% +hand you could knock it down they said + + + align:start position:0% +hand you could knock it down they said +the story is that they had to + + align:start position:0% +the story is that they had to + + + align:start position:0% +the story is that they had to +reconfigure the whole thing raman new + + align:start position:0% +reconfigure the whole thing raman new + + + align:start position:0% +reconfigure the whole thing raman new +jersey + + align:start position:0% +jersey + + + align:start position:0% +jersey +so with we're talking about a person who + + align:start position:0% +so with we're talking about a person who + + + align:start position:0% +so with we're talking about a person who +really is an outsider + + align:start position:0% +really is an outsider + + + align:start position:0% +really is an outsider +a person who really lives + + align:start position:0% +a person who really lives + + + align:start position:0% +a person who really lives +in another + + align:start position:0% +in another + + + align:start position:0% +in another +minds a state of mind + + align:start position:0% +minds a state of mind + + + align:start position:0% +minds a state of mind +um + + align:start position:0% +um + + + align:start position:0% +um +i saw some people who had that state of + + align:start position:0% +i saw some people who had that state of + + + align:start position:0% +i saw some people who had that state of +mind i saw a program on television + + align:start position:0% +mind i saw a program on television + + + align:start position:0% +mind i saw a program on television +a documentary + + align:start position:0% +a documentary + + + align:start position:0% +a documentary +we talked about savants and other types + + align:start position:0% +we talked about savants and other types + + + align:start position:0% +we talked about savants and other types +of + + align:start position:0% +of + + + align:start position:0% +of +people that have the shame of + + align:start position:0% +people that have the shame of + + + align:start position:0% +people that have the shame of +shamanistic personality they always had + + align:start position:0% +shamanistic personality they always had + + + align:start position:0% +shamanistic personality they always had +these traumatic childhood experiences + + align:start position:0% +these traumatic childhood experiences + + + align:start position:0% +these traumatic childhood experiences +where they tried to get away from the + + align:start position:0% +where they tried to get away from the + + + align:start position:0% +where they tried to get away from the +world + + align:start position:0% + + + + align:start position:0% + +and uh they showed this one guy + + align:start position:0% +and uh they showed this one guy + + + align:start position:0% +and uh they showed this one guy +now this is what i'm telling you now is + + align:start position:0% +now this is what i'm telling you now is + + + align:start position:0% +now this is what i'm telling you now is +good scientific stuff we're not talking + + align:start position:0% +good scientific stuff we're not talking + + + align:start position:0% +good scientific stuff we're not talking +about alien visitations + + align:start position:0% +about alien visitations + + + align:start position:0% +about alien visitations +all right + + align:start position:0% +all right + + + align:start position:0% +all right +this is very well documented these + + align:start position:0% +this is very well documented these + + + align:start position:0% +this is very well documented these +people that have been studied in college + + align:start position:0% +people that have been studied in college + + + align:start position:0% +people that have been studied in college +by researchers + + align:start position:0% +by researchers + + + align:start position:0% +by researchers +they had this one man who was about when + + align:start position:0% +they had this one man who was about when + + + align:start position:0% +they had this one man who was about when +he was 50 years old + + align:start position:0% +he was 50 years old + + + align:start position:0% +he was 50 years old +he could tell you the weather of every + + align:start position:0% +he could tell you the weather of every + + + align:start position:0% +he could tell you the weather of every +day of his life + + align:start position:0% +day of his life + + + align:start position:0% +day of his life +well after three or four + + align:start position:0% +well after three or four + + + align:start position:0% +well after three or four +you say well what was the weather like + + align:start position:0% +you say well what was the weather like + + + align:start position:0% +you say well what was the weather like +uh + + align:start position:0% +uh + + + align:start position:0% +uh +november 6 1942 i ran that day + + align:start position:0% + + + + align:start position:0% + +and they go back and check and sure + + align:start position:0% +and they go back and check and sure + + + align:start position:0% +and they go back and check and sure +enough it was + + align:start position:0% +enough it was + + + align:start position:0% +enough it was +now how do you explain that well it + + align:start position:0% +now how do you explain that well it + + + align:start position:0% +now how do you explain that well it +turns out + + align:start position:0% +turns out + + + align:start position:0% +turns out +basically he knew nothing else + + align:start position:0% + + + + align:start position:0% + +but he memorized those things to keep + + align:start position:0% +but he memorized those things to keep + + + align:start position:0% +but he memorized those things to keep +whatever problem he had as a child out + + align:start position:0% +whatever problem he had as a child out + + + align:start position:0% +whatever problem he had as a child out +of his mind + + align:start position:0% +of his mind + + + align:start position:0% +of his mind +uh and so they tried to rehabilitate him + + align:start position:0% +uh and so they tried to rehabilitate him + + + align:start position:0% +uh and so they tried to rehabilitate him +and they showed a scene where + + align:start position:0% +and they showed a scene where + + + align:start position:0% +and they showed a scene where +he goes to the street to cross the + + align:start position:0% +he goes to the street to cross the + + + align:start position:0% +he goes to the street to cross the +street + + align:start position:0% +street + + + align:start position:0% +street +and the sign is saying + + align:start position:0% +and the sign is saying + + + align:start position:0% +and the sign is saying +go and he gets out in the middle of the + + align:start position:0% +go and he gets out in the middle of the + + + align:start position:0% +go and he gets out in the middle of the +street and the sign says stop and he + + align:start position:0% +street and the sign says stop and he + + + align:start position:0% +street and the sign says stop and he +stops + + align:start position:0% +stops + + + align:start position:0% +stops +you know he can he just doesn't + + align:start position:0% +you know he can he just doesn't + + + align:start position:0% +you know he can he just doesn't +no he i think his mother kept him close + + align:start position:0% +no he i think his mother kept him close + + + align:start position:0% +no he i think his mother kept him close +to her all his life he just didn't know + + align:start position:0% +to her all his life he just didn't know + + + align:start position:0% +to her all his life he just didn't know +those things the more he got + + align:start position:0% +those things the more he got + + + align:start position:0% +those things the more he got +into society got a job + + align:start position:0% +into society got a job + + + align:start position:0% +into society got a job +he could only hold a job for something + + align:start position:0% +he could only hold a job for something + + + align:start position:0% +he could only hold a job for something +like one hour a day + + align:start position:0% +like one hour a day + + + align:start position:0% +like one hour a day +at first + + align:start position:0% +at first + + + align:start position:0% +at first +cleaning the busing tables + + align:start position:0% +cleaning the busing tables + + + align:start position:0% +cleaning the busing tables +the more he got + + align:start position:0% +the more he got + + + align:start position:0% +the more he got +socialized + + align:start position:0% +socialized + + + align:start position:0% +socialized +the more he began to lose that skill + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% +um + + + align:start position:0% +um +they say uh that the um + + align:start position:0% +they say uh that the um + + + align:start position:0% +they say uh that the um +the bards that uh + + align:start position:0% +the bards that uh + + + align:start position:0% +the bards that uh +back in um + + align:start position:0% + + + + align:start position:0% + +400 bc + + align:start position:0% +400 bc + + + align:start position:0% +400 bc +once we were going around talking + + align:start position:0% +once we were going around talking + + + align:start position:0% +once we were going around talking +about former and all of it + + align:start position:0% +about former and all of it + + + align:start position:0% +about former and all of it +they said that they could tell they had + + align:start position:0% +they said that they could tell they had + + + align:start position:0% +they said that they could tell they had +memorized i read some place where they + + align:start position:0% +memorized i read some place where they + + + align:start position:0% +memorized i read some place where they +where these people had memorized + + align:start position:0% +where these people had memorized + + + align:start position:0% +where these people had memorized +something like a million lines of verse + + align:start position:0% +something like a million lines of verse + + + align:start position:0% +something like a million lines of verse +before + + align:start position:0% +before + + + align:start position:0% +before +now a million lines of verse + + align:start position:0% +now a million lines of verse + + + align:start position:0% +now a million lines of verse +so i sat down one day and i did a + + align:start position:0% +so i sat down one day and i did a + + + align:start position:0% +so i sat down one day and i did a +calculation i know how long the lines + + align:start position:0% +calculation i know how long the lines + + + align:start position:0% +calculation i know how long the lines +are about the same length of a line in + + align:start position:0% +are about the same length of a line in + + + align:start position:0% +are about the same length of a line in +shakespeare + + align:start position:0% +shakespeare + + + align:start position:0% +shakespeare +so i did you know back of the hand kind + + align:start position:0% +so i did you know back of the hand kind + + + align:start position:0% +so i did you know back of the hand kind +of a calculation + + align:start position:0% +of a calculation + + + align:start position:0% +of a calculation +10 volumes of shakespeare + + align:start position:0% +10 volumes of shakespeare + + + align:start position:0% +10 volumes of shakespeare +now i concluded + + align:start position:0% + + + + align:start position:0% + +from that television + + align:start position:0% +from that television + + + align:start position:0% +from that television +program i saw + + align:start position:0% +program i saw + + + align:start position:0% +program i saw +that these pr people probably didn't + + align:start position:0% +that these pr people probably didn't + + + align:start position:0% +that these pr people probably didn't +know a whole lot of anything else + + align:start position:0% +know a whole lot of anything else + + + align:start position:0% +know a whole lot of anything else +uh one other program that i saw uh + + align:start position:0% +uh one other program that i saw uh + + + align:start position:0% +uh one other program that i saw uh +was one where they were talking about + + align:start position:0% +was one where they were talking about + + + align:start position:0% +was one where they were talking about +about um + + align:start position:0% +about um + + + align:start position:0% +about um +these professional scrabble players + + align:start position:0% +these professional scrabble players + + + align:start position:0% +these professional scrabble players +actually i think yeah they play for + + align:start position:0% +actually i think yeah they play for + + + align:start position:0% +actually i think yeah they play for +money + + align:start position:0% + + + + align:start position:0% + +and they talked about how many words + + align:start position:0% +and they talked about how many words + + + align:start position:0% +and they talked about how many words +these people + + align:start position:0% +these people + + + align:start position:0% +these people +had memorized and not only that but they + + align:start position:0% +had memorized and not only that but they + + + align:start position:0% +had memorized and not only that but they +had a skill + + align:start position:0% +had a skill + + + align:start position:0% +had a skill +to um + + align:start position:0% +to um + + + align:start position:0% +to um +to take the words on their uh + + align:start position:0% +to take the words on their uh + + + align:start position:0% +to take the words on their uh +palette + + align:start position:0% +palette + + + align:start position:0% +palette +i mean the letters + + align:start position:0% +i mean the letters + + + align:start position:0% +i mean the letters +and be able to turn them around in their + + align:start position:0% +and be able to turn them around in their + + + align:start position:0% +and be able to turn them around in their +minds + + align:start position:0% +minds + + + align:start position:0% +minds +to see the patterns before they put them + + align:start position:0% +to see the patterns before they put them + + + align:start position:0% +to see the patterns before they put them +down we try to do i try to do that if + + align:start position:0% +down we try to do i try to do that if + + + align:start position:0% +down we try to do i try to do that if +it's obvious i can do it i can do it + + align:start position:0% +it's obvious i can do it i can do it + + + align:start position:0% +it's obvious i can do it i can do it +with three letters if there's one but + + align:start position:0% +with three letters if there's one but + + + align:start position:0% +with three letters if there's one but +seven yeah it takes an effort these + + align:start position:0% +seven yeah it takes an effort these + + + align:start position:0% +seven yeah it takes an effort these +people just do it like that + + align:start position:0% +people just do it like that + + + align:start position:0% +people just do it like that +and + + align:start position:0% +and + + + align:start position:0% +and +um + + align:start position:0% +um + + + align:start position:0% +um +then they and they had all these + + align:start position:0% +then they and they had all these + + + align:start position:0% +then they and they had all these +interviews with the the winners + + align:start position:0% +interviews with the the winners + + + align:start position:0% +interviews with the the winners +it turns out in the end + + align:start position:0% +it turns out in the end + + + align:start position:0% +it turns out in the end +that the winners + + align:start position:0% +that the winners + + + align:start position:0% +that the winners +know the meanings of very few words + + align:start position:0% +know the meanings of very few words + + + align:start position:0% +know the meanings of very few words +but they know a word from a non-word + + align:start position:0% + + + + align:start position:0% + +and they interviewed some of them at + + align:start position:0% +and they interviewed some of them at + + + align:start position:0% +and they interviewed some of them at +home and and these people had shamanic + + align:start position:0% +home and and these people had shamanic + + + align:start position:0% +home and and these people had shamanic +personalities i mean um + + align:start position:0% +personalities i mean um + + + align:start position:0% +personalities i mean um +uh you just don't see two of them + + align:start position:0% +uh you just don't see two of them + + + align:start position:0% +uh you just don't see two of them +sitting down for long organizing + + align:start position:0% +sitting down for long organizing + + + align:start position:0% +sitting down for long organizing +together + + align:start position:0% +together + + + align:start position:0% +together +okay so in my mind i don't see shane + + align:start position:0% +okay so in my mind i don't see shane + + + align:start position:0% +okay so in my mind i don't see shane +uh oh i tell you where else you find + + align:start position:0% +uh oh i tell you where else you find + + + align:start position:0% +uh oh i tell you where else you find +shane + + align:start position:0% +shane + + + align:start position:0% +shane +a shaman + + align:start position:0% +a shaman + + + align:start position:0% +a shaman +i knew a person who was not ashamed but + + align:start position:0% +i knew a person who was not ashamed but + + + align:start position:0% +i knew a person who was not ashamed but +she said she was taught by shane and so + + align:start position:0% +she said she was taught by shane and so + + + align:start position:0% +she said she was taught by shane and so +she knows some of the shame and skills + + align:start position:0% +she knows some of the shame and skills + + + align:start position:0% +she knows some of the shame and skills +native + + align:start position:0% +native + + + align:start position:0% +native +americans still have you can still find + + align:start position:0% +americans still have you can still find + + + align:start position:0% +americans still have you can still find +a shape + + align:start position:0% +a shape + + + align:start position:0% +a shape +out there + + align:start position:0% +out there + + + align:start position:0% +out there +um + + align:start position:0% +um + + + align:start position:0% +um +so what happened was but going back to + + align:start position:0% +so what happened was but going back to + + + align:start position:0% +so what happened was but going back to +civilization + + align:start position:0% +civilization + + + align:start position:0% +civilization +uh + + align:start position:0% +uh + + + align:start position:0% +uh +the priests were able to + + align:start position:0% +the priests were able to + + + align:start position:0% +the priests were able to +find cycles + + align:start position:0% +find cycles + + + align:start position:0% +find cycles +that were connected first with the moon + + align:start position:0% +that were connected first with the moon + + + align:start position:0% +that were connected first with the moon +than with the sun + + align:start position:0% +than with the sun + + + align:start position:0% +than with the sun +by which they were able to organize + + align:start position:0% +by which they were able to organize + + + align:start position:0% +by which they were able to organize +everybody to plant + + align:start position:0% +everybody to plant + + + align:start position:0% +everybody to plant +and to read + + align:start position:0% +and to read + + + align:start position:0% +and to read +and that kit and so therefore + + align:start position:0% +and that kit and so therefore + + + align:start position:0% +and that kit and so therefore +it's very easy to understand from that + + align:start position:0% +it's very easy to understand from that + + + align:start position:0% +it's very easy to understand from that +who invented mathematics + + align:start position:0% +who invented mathematics + + + align:start position:0% +who invented mathematics +and astronomy + + align:start position:0% +and astronomy + + + align:start position:0% +and astronomy +okay these priests + + align:start position:0% + + + + align:start position:0% + +uh now i'm getting to my point now i'm + + align:start position:0% +uh now i'm getting to my point now i'm + + + align:start position:0% +uh now i'm getting to my point now i'm +getting to my point + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% + + + + align:start position:0% + +joseph campbell + + align:start position:0% +joseph campbell + + + align:start position:0% +joseph campbell +makes the big point + + align:start position:0% +makes the big point + + + align:start position:0% +makes the big point +that in primitive society + + align:start position:0% +that in primitive society + + + align:start position:0% +that in primitive society +um + + align:start position:0% + + + + align:start position:0% + +no + + align:start position:0% +no + + + align:start position:0% +no +in the transition from + + align:start position:0% +in the transition from + + + align:start position:0% +in the transition from +small primitive societies to big ones + + align:start position:0% +small primitive societies to big ones + + + align:start position:0% +small primitive societies to big ones +okay + + align:start position:0% +okay + + + align:start position:0% +okay +instead of having + + align:start position:0% +instead of having + + + align:start position:0% +instead of having +six or seven people in a family group + + align:start position:0% +six or seven people in a family group + + + align:start position:0% +six or seven people in a family group +now you're talking about hundreds + + align:start position:0% +now you're talking about hundreds + + + align:start position:0% +now you're talking about hundreds +and they're eating and they're and + + align:start position:0% +and they're eating and they're and + + + align:start position:0% +and they're eating and they're and +they're um + + align:start position:0% +they're um + + + align:start position:0% +they're um +are hurting these the the the these uh + + align:start position:0% +are hurting these the the the these uh + + + align:start position:0% +are hurting these the the the these uh +reindeer or cattle + + align:start position:0% + + + + align:start position:0% + +here's what happens now joseph campbell + + align:start position:0% +here's what happens now joseph campbell + + + align:start position:0% +here's what happens now joseph campbell +i think is right about this + + align:start position:0% +i think is right about this + + + align:start position:0% +i think is right about this +he does a lot of anthropocultural + + align:start position:0% +he does a lot of anthropocultural + + + align:start position:0% +he does a lot of anthropocultural +anthropology + + align:start position:0% +anthropology + + + align:start position:0% +anthropology +this is germane to all of this and i'll + + align:start position:0% +this is germane to all of this and i'll + + + align:start position:0% +this is germane to all of this and i'll +make all of this make sense before the + + align:start position:0% +make all of this make sense before the + + + align:start position:0% +make all of this make sense before the +class is out + + align:start position:0% +class is out + + + align:start position:0% +class is out +i don't ask you to trust me but that's a + + align:start position:0% +i don't ask you to trust me but that's a + + + align:start position:0% +i don't ask you to trust me but that's a +promise + + align:start position:0% +promise + + + align:start position:0% +promise +joseph campbell says + + align:start position:0% +joseph campbell says + + + align:start position:0% +joseph campbell says +that once you have a successful society + + align:start position:0% +that once you have a successful society + + + align:start position:0% +that once you have a successful society +successful in terms of holding people + + align:start position:0% +successful in terms of holding people + + + align:start position:0% +successful in terms of holding people +together and feeding everybody + + align:start position:0% + + + + align:start position:0% + +you will find that your biggest problem + + align:start position:0% +you will find that your biggest problem + + + align:start position:0% +you will find that your biggest problem +is not family + + align:start position:0% +is not family + + + align:start position:0% +is not family +the biggest problem is not disease + + align:start position:0% +the biggest problem is not disease + + + align:start position:0% +the biggest problem is not disease +he says you want to guess what he says + + align:start position:0% +he says you want to guess what he says + + + align:start position:0% +he says you want to guess what he says +your biggest problem is + + align:start position:0% + + + + align:start position:0% + +men with free time + + align:start position:0% + + + + align:start position:0% + +because you get a bad combination the + + align:start position:0% +because you get a bad combination the + + + align:start position:0% +because you get a bad combination the +women don't have free time + + align:start position:0% +women don't have free time + + + align:start position:0% +women don't have free time +you got kids + + align:start position:0% +you got kids + + + align:start position:0% +you got kids +that's a that's 24 hours a day + + align:start position:0% +that's a that's 24 hours a day + + + align:start position:0% +that's a that's 24 hours a day +men with free time + + align:start position:0% +men with free time + + + align:start position:0% +men with free time +here's the bad combination + + align:start position:0% + + + + align:start position:0% + +because everybody's what they do they + + align:start position:0% +because everybody's what they do they + + + align:start position:0% +because everybody's what they do they +if they if they want to shoot they just + + align:start position:0% +if they if they want to shoot they just + + + align:start position:0% +if they if they want to shoot they just +go out get one + + align:start position:0% +go out get one + + + align:start position:0% +go out get one +they got free time men with free time + + align:start position:0% +they got free time men with free time + + + align:start position:0% +they got free time men with free time +here's the bad combination + + align:start position:0% + + + + align:start position:0% + +free time + + align:start position:0% +free time + + + align:start position:0% +free time +uh + + align:start position:0% +uh + + + align:start position:0% +uh +and + + align:start position:0% +and + + + align:start position:0% +and +inclination to organizing hierarchical + + align:start position:0% +inclination to organizing hierarchical + + + align:start position:0% +inclination to organizing hierarchical +groups + + align:start position:0% + + + + align:start position:0% + +and guess what the last piece of the + + align:start position:0% +and guess what the last piece of the + + + align:start position:0% +and guess what the last piece of the +positive + + align:start position:0% +positive + + + align:start position:0% +positive +high levels of testosterone + + align:start position:0% + + + + align:start position:0% + +high levels of testosterone + + align:start position:0% +high levels of testosterone + + + align:start position:0% +high levels of testosterone +that's a bad combination + + align:start position:0% +that's a bad combination + + + align:start position:0% +that's a bad combination +free time + + align:start position:0% +free time + + + align:start position:0% +free time +men men with free time + + align:start position:0% +men men with free time + + + align:start position:0% +men men with free time +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so what happens is + + align:start position:0% +so what happens is + + + align:start position:0% +so what happens is +that to let out that energy + + align:start position:0% + + + + align:start position:0% + +one of the things that been learned to + + align:start position:0% +one of the things that been learned to + + + align:start position:0% +one of the things that been learned to +do + + align:start position:0% +do + + + align:start position:0% +do +was to hunt other men + + align:start position:0% + + + + align:start position:0% + +that is the root of the heroic story + + align:start position:0% + + + + align:start position:0% + +and what and these ancient or hurting + + align:start position:0% +and what and these ancient or hurting + + + align:start position:0% +and what and these ancient or hurting +societies + + align:start position:0% +societies + + + align:start position:0% +societies +anthropologists call warrior warrior + + align:start position:0% +anthropologists call warrior warrior + + + align:start position:0% +anthropologists call warrior warrior +herding societies they were warriors + + align:start position:0% + + + + align:start position:0% + +civilization was priests + + align:start position:0% +civilization was priests + + + align:start position:0% +civilization was priests +and farmers + + align:start position:0% + + + + align:start position:0% + +all right + + align:start position:0% +all right + + + align:start position:0% +all right +now here's the last piece of this puzzle + + align:start position:0% + + + + align:start position:0% + +as civilization got more complicated you + + align:start position:0% +as civilization got more complicated you + + + align:start position:0% +as civilization got more complicated you +get more people + + align:start position:0% +get more people + + + align:start position:0% +get more people +got bigger problems + + align:start position:0% +got bigger problems + + + align:start position:0% +got bigger problems +uh the priest can't handle keep + + align:start position:0% +uh the priest can't handle keep + + + align:start position:0% +uh the priest can't handle keep +everybody together just on holidays + + align:start position:0% +everybody together just on holidays + + + align:start position:0% +everybody together just on holidays +and you know and + + align:start position:0% +and you know and + + + align:start position:0% +and you know and +and and sundays if you want to put it + + align:start position:0% +and and sundays if you want to put it + + + align:start position:0% +and and sundays if you want to put it +like that + + align:start position:0% +like that + + + align:start position:0% +like that +you have to have a principle of force + + align:start position:0% + + + + align:start position:0% + +so what happened was + + align:start position:0% +so what happened was + + + align:start position:0% +so what happened was +that the the warrior herders the young + + align:start position:0% +that the the warrior herders the young + + + align:start position:0% +that the the warrior herders the young +men would get out and say well look we + + align:start position:0% +men would get out and say well look we + + + align:start position:0% +men would get out and say well look we +got to prove our manhood + + align:start position:0% +got to prove our manhood + + + align:start position:0% +got to prove our manhood +so they run out to uh or + + align:start position:0% +so they run out to uh or + + + align:start position:0% +so they run out to uh or +run out over to some civilization kill + + align:start position:0% +run out over to some civilization kill + + + align:start position:0% +run out over to some civilization kill +someone + + align:start position:0% +someone + + + align:start position:0% +someone +still steal some women + + align:start position:0% + + + + align:start position:0% + +uh then the civilization started + + align:start position:0% +uh then the civilization started + + + align:start position:0% +uh then the civilization started +building walls to keep them out + + align:start position:0% + + + + align:start position:0% + +and then what happened was the priests + + align:start position:0% +and then what happened was the priests + + + align:start position:0% +and then what happened was the priests +started hiring them as mercenaries + + align:start position:0% +started hiring them as mercenaries + + + align:start position:0% +started hiring them as mercenaries +the priests started hiring them as first + + align:start position:0% +the priests started hiring them as first + + + align:start position:0% +the priests started hiring them as first +of all mercenaries + + align:start position:0% +of all mercenaries + + + align:start position:0% +of all mercenaries +whenever they uh whenever one civilized + + align:start position:0% +whenever they uh whenever one civilized + + + align:start position:0% +whenever they uh whenever one civilized +group + + align:start position:0% +group + + + align:start position:0% +group +thought that they needed something from + + align:start position:0% +thought that they needed something from + + + align:start position:0% +thought that they needed something from +another civilian + + align:start position:0% + + + + align:start position:0% + +okay some bugs got in and ate all of the + + align:start position:0% +okay some bugs got in and ate all of the + + + align:start position:0% +okay some bugs got in and ate all of the +wheat + + align:start position:0% +wheat + + + align:start position:0% +wheat +over here + + align:start position:0% +over here + + + align:start position:0% +over here +these people got wheat over there + + align:start position:0% +these people got wheat over there + + + align:start position:0% +these people got wheat over there +they're not going to give you any wheat + + align:start position:0% +they're not going to give you any wheat + + + align:start position:0% +they're not going to give you any wheat +over here so you hire some of these + + align:start position:0% +over here so you hire some of these + + + align:start position:0% +over here so you hire some of these +mercenaries go beat up on a couple of + + align:start position:0% +mercenaries go beat up on a couple of + + + align:start position:0% +mercenaries go beat up on a couple of +them and bring some feedback + + align:start position:0% +them and bring some feedback + + + align:start position:0% +them and bring some feedback +uh + + align:start position:0% +uh + + + align:start position:0% +uh +then you have all of these problems + + align:start position:0% +then you have all of these problems + + + align:start position:0% +then you have all of these problems +within the culture + + align:start position:0% +within the culture + + + align:start position:0% +within the culture +people are fighting + + align:start position:0% +people are fighting + + + align:start position:0% +people are fighting +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so then you have these people not as + + align:start position:0% +so then you have these people not as + + + align:start position:0% +so then you have these people not as +mercenaries but you're hired as police + + align:start position:0% + + + + align:start position:0% + +you see it the invention of the king + + align:start position:0% + + + + align:start position:0% + +you already got the high priest the king + + align:start position:0% +you already got the high priest the king + + + align:start position:0% +you already got the high priest the king +is really an outsider + + align:start position:0% +is really an outsider + + + align:start position:0% +is really an outsider +that's what happened the roman empire + + align:start position:0% +that's what happened the roman empire + + + align:start position:0% +that's what happened the roman empire +the romans came in they just didn't + + align:start position:0% +the romans came in they just didn't + + + align:start position:0% +the romans came in they just didn't +subdue everybody and beat everybody out + + align:start position:0% +subdue everybody and beat everybody out + + + align:start position:0% +subdue everybody and beat everybody out +they just came in and became + + align:start position:0% +they just came in and became + + + align:start position:0% +they just came in and became +the police + + align:start position:0% + + + + align:start position:0% + +they left a lot of the high priest in + + align:start position:0% +they left a lot of the high priest in + + + align:start position:0% +they left a lot of the high priest in +control + + align:start position:0% +control + + + align:start position:0% +control +so what i'm saying now is + + align:start position:0% +so what i'm saying now is + + + align:start position:0% +so what i'm saying now is +that the religion in religion in warrior + + align:start position:0% +that the religion in religion in warrior + + + align:start position:0% +that the religion in religion in warrior +societies is based on + + align:start position:0% + + + + align:start position:0% + +kinship and they are they + + align:start position:0% +kinship and they are they + + + align:start position:0% +kinship and they are they +they don't believe + + align:start position:0% +they don't believe + + + align:start position:0% +they don't believe +that they lose anything by + + align:start position:0% +that they lose anything by + + + align:start position:0% +that they lose anything by +adopting your religion + + align:start position:0% +adopting your religion + + + align:start position:0% +adopting your religion +you can't adopt theirs because you're + + align:start position:0% +you can't adopt theirs because you're + + + align:start position:0% +you can't adopt theirs because you're +not a member of the family + + align:start position:0% +not a member of the family + + + align:start position:0% +not a member of the family +so warrior hurting societies are not + + align:start position:0% +so warrior hurting societies are not + + + align:start position:0% +so warrior hurting societies are not +like civilized society civilized + + align:start position:0% +like civilized society civilized + + + align:start position:0% +like civilized society civilized +societies compete + + align:start position:0% +societies compete + + + align:start position:0% +societies compete +to debt to the debt over religion + + align:start position:0% +to debt to the debt over religion + + + align:start position:0% +to debt to the debt over religion +warrior hurting society doesn't matter + + align:start position:0% +warrior hurting society doesn't matter + + + align:start position:0% +warrior hurting society doesn't matter +that much to them + + align:start position:0% + + + + align:start position:0% + +the pagans that we're talking about + + align:start position:0% +the pagans that we're talking about + + + align:start position:0% +the pagans that we're talking about +impossible + + align:start position:0% +impossible + + + align:start position:0% +impossible +were warrior hurting arabs + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so so so fearfully really wasn't giving + + align:start position:0% +so so so fearfully really wasn't giving + + + align:start position:0% +so so so fearfully really wasn't giving +up a whole lot to become + + align:start position:0% +up a whole lot to become + + + align:start position:0% +up a whole lot to become +a christian + + align:start position:0% +a christian + + + align:start position:0% +a christian +not a whole lot + + align:start position:0% +not a whole lot + + + align:start position:0% +not a whole lot +i mean uh even even um + + align:start position:0% +i mean uh even even um + + + align:start position:0% +i mean uh even even um +when muhammad + + align:start position:0% +when muhammad + + + align:start position:0% +when muhammad +invented islam + + align:start position:0% +invented islam + + + align:start position:0% +invented islam +he did it as an attempt + + align:start position:0% +he did it as an attempt + + + align:start position:0% +he did it as an attempt +to synthesize + + align:start position:0% +to synthesize + + + align:start position:0% +to synthesize +their own religions + + align:start position:0% +their own religions + + + align:start position:0% +their own religions +with christianity and judaism + + align:start position:0% +with christianity and judaism + + + align:start position:0% +with christianity and judaism +and one other one um + + align:start position:0% +and one other one um + + + align:start position:0% +and one other one um +zoroastrianism + + align:start position:0% +zoroastrianism + + + align:start position:0% +zoroastrianism +so + + align:start position:0% +so + + + align:start position:0% +so +uh any person who comes in here who says + + align:start position:0% +uh any person who comes in here who says + + + align:start position:0% +uh any person who comes in here who says +that i am a muslim + + align:start position:0% +that i am a muslim + + + align:start position:0% +that i am a muslim +will say that i have very few arguments + + align:start position:0% +will say that i have very few arguments + + + align:start position:0% +will say that i have very few arguments +with you about religion + + align:start position:0% +with you about religion + + + align:start position:0% +with you about religion +you will say i have a lot of arguments + + align:start position:0% +you will say i have a lot of arguments + + + align:start position:0% +you will say i have a lot of arguments +with you about religion but they will + + align:start position:0% +with you about religion but they will + + + align:start position:0% +with you about religion but they will +say i don't have a whole lot of + + align:start position:0% +say i don't have a whole lot of + + + align:start position:0% +say i don't have a whole lot of +arguments with you about it because part + + align:start position:0% +arguments with you about it because part + + + align:start position:0% +arguments with you about it because part +of my religion is already built in + + align:start position:0% +of my religion is already built in + + + align:start position:0% +of my religion is already built in +christianity + + align:start position:0% +christianity + + + align:start position:0% +christianity +so fear fears wasn't given up a whole + + align:start position:0% +so fear fears wasn't given up a whole + + + align:start position:0% +so fear fears wasn't given up a whole +lot by doing it + + align:start position:0% +lot by doing it + + + align:start position:0% +lot by doing it +it meant almost everything to possible + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +uh so i thought i'd go through that long + + align:start position:0% +uh so i thought i'd go through that long + + + align:start position:0% +uh so i thought i'd go through that long +spiel + + align:start position:0% +spiel + + + align:start position:0% +spiel +because we have because it's built into + + align:start position:0% +because we have because it's built into + + + align:start position:0% +because we have because it's built into +the story here + + align:start position:0% +the story here + + + align:start position:0% +the story here +these things are built into the story + + align:start position:0% +these things are built into the story + + + align:start position:0% +these things are built into the story +um + + align:start position:0% +um + + + align:start position:0% +um +what had just happened was + + align:start position:0% +what had just happened was + + + align:start position:0% +what had just happened was +what created the knights and what made + + align:start position:0% +what created the knights and what made + + + align:start position:0% +what created the knights and what made +them who they were + + align:start position:0% +them who they were + + + align:start position:0% +them who they were +was that there was this big void + + align:start position:0% +was that there was this big void + + + align:start position:0% +was that there was this big void +in the western world after the roman + + align:start position:0% +in the western world after the roman + + + align:start position:0% +in the western world after the roman +empire collapse + + align:start position:0% + + + + align:start position:0% + +and when any time some big power + + align:start position:0% +and when any time some big power + + + align:start position:0% +and when any time some big power +collapse collapses + + align:start position:0% +collapse collapses + + + align:start position:0% +collapse collapses +a whole lot of people rushing in to fill + + align:start position:0% +a whole lot of people rushing in to fill + + + align:start position:0% +a whole lot of people rushing in to fill +the void and get the piece of the action + + align:start position:0% +the void and get the piece of the action + + + align:start position:0% +the void and get the piece of the action +okay then came islam + + align:start position:0% +okay then came islam + + + align:start position:0% +okay then came islam +that lasted for a while went back and + + align:start position:0% +that lasted for a while went back and + + + align:start position:0% +that lasted for a while went back and +now you have the dark ages + + align:start position:0% +now you have the dark ages + + + align:start position:0% +now you have the dark ages +and then when everything comes back + + align:start position:0% +and then when everything comes back + + + align:start position:0% +and then when everything comes back +together you start having the middle + + align:start position:0% +together you start having the middle + + + align:start position:0% +together you start having the middle +ages + + align:start position:0% +ages + + + align:start position:0% +ages +and when did you start having the middle + + align:start position:0% +and when did you start having the middle + + + align:start position:0% +and when did you start having the middle +ages + + align:start position:0% +ages + + + align:start position:0% +ages +when charlemagne + + align:start position:0% +when charlemagne + + + align:start position:0% +when charlemagne +uh started organizing all of these dukes + + align:start position:0% +uh started organizing all of these dukes + + + align:start position:0% +uh started organizing all of these dukes +under one king + + align:start position:0% + + + + align:start position:0% + +some people would say it was otto first + + align:start position:0% + + + + align:start position:0% + +who came after charlemagne but + + align:start position:0% +who came after charlemagne but + + + align:start position:0% +who came after charlemagne but +nevertheless + + align:start position:0% +nevertheless + + + align:start position:0% +nevertheless +okay so we're talking about a time now + + align:start position:0% +okay so we're talking about a time now + + + align:start position:0% +okay so we're talking about a time now +when + + align:start position:0% +when + + + align:start position:0% +when +uh the the west was ruled by arabs who + + align:start position:0% +uh the the west was ruled by arabs who + + + align:start position:0% +uh the the west was ruled by arabs who +left + + align:start position:0% +left + + + align:start position:0% +left +and you got this big void and you have + + align:start position:0% +and you got this big void and you have + + + align:start position:0% +and you got this big void and you have +these a feudal system + + align:start position:0% +these a feudal system + + + align:start position:0% +these a feudal system +and the knights + + align:start position:0% + + + + align:start position:0% + +serve a feudal lord + + align:start position:0% + + + + align:start position:0% + +and there is there's something about + + align:start position:0% +and there is there's something about + + + align:start position:0% +and there is there's something about +some of these knights that say + + align:start position:0% +some of these knights that say + + + align:start position:0% +some of these knights that say +well look uh yeah we're ravaging the + + align:start position:0% +well look uh yeah we're ravaging the + + + align:start position:0% +well look uh yeah we're ravaging the +land and all of that + + align:start position:0% +land and all of that + + + align:start position:0% +land and all of that +but there's got to be some principles on + + align:start position:0% +but there's got to be some principles on + + + align:start position:0% +but there's got to be some principles on +all of this + + align:start position:0% +all of this + + + align:start position:0% +all of this +and some of these nights really did + + align:start position:0% +and some of these nights really did + + + align:start position:0% +and some of these nights really did +bring chivalry + + align:start position:0% +bring chivalry + + + align:start position:0% +bring chivalry +to a high peak level + + align:start position:0% +to a high peak level + + + align:start position:0% +to a high peak level +uh and + + align:start position:0% +uh and + + + align:start position:0% +uh and +some of them even call themselves + + align:start position:0% +some of them even call themselves + + + align:start position:0% +some of them even call themselves +priests like the knights templar + + align:start position:0% +priests like the knights templar + + + align:start position:0% +priests like the knights templar +they thought of themselves + + align:start position:0% +they thought of themselves + + + align:start position:0% +they thought of themselves +so that's that's that's where we are + + align:start position:0% +so that's that's that's where we are + + + align:start position:0% +so that's that's that's where we are +with all of this and that + + align:start position:0% +with all of this and that + + + align:start position:0% +with all of this and that +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +uh + + align:start position:0% +uh + + + align:start position:0% +uh +one of one thing that isn't + + align:start position:0% +one of one thing that isn't + + + align:start position:0% +one of one thing that isn't +emphasized in here + + align:start position:0% +emphasized in here + + + align:start position:0% +emphasized in here +uh like it is other places the killing + + align:start position:0% +uh like it is other places the killing + + + align:start position:0% +uh like it is other places the killing +of the dragon + + align:start position:0% + + + + align:start position:0% + +is that the purpose of mythology + + align:start position:0% + + + + align:start position:0% + +is + + align:start position:0% + + + + align:start position:0% + +hold a society together + + align:start position:0% + + + + align:start position:0% + +and one of his functions is + + align:start position:0% +and one of his functions is + + + align:start position:0% +and one of his functions is +is to organize the men with the free + + align:start position:0% +is to organize the men with the free + + + align:start position:0% +is to organize the men with the free +time + + align:start position:0% +time + + + align:start position:0% +time +and say now if you're going to kill + + align:start position:0% +and say now if you're going to kill + + + align:start position:0% +and say now if you're going to kill +somebody they got to be smooth + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +uh and why have these things lasted + + align:start position:0% +uh and why have these things lasted + + + align:start position:0% +uh and why have these things lasted +so long well what we find out is that + + align:start position:0% +so long well what we find out is that + + + align:start position:0% +so long well what we find out is that +they've lasted a long time + + align:start position:0% +they've lasted a long time + + + align:start position:0% +they've lasted a long time +because they become metaphors for + + align:start position:0% +because they become metaphors for + + + align:start position:0% +because they become metaphors for +everybody's problem + + align:start position:0% +everybody's problem + + + align:start position:0% +everybody's problem +big with your big problems in your life + + align:start position:0% +big with your big problems in your life + + + align:start position:0% +big with your big problems in your life +and one that i like to talk about + + align:start position:0% +and one that i like to talk about + + + align:start position:0% +and one that i like to talk about +make mention here + + align:start position:0% +make mention here + + + align:start position:0% +make mention here +is uh let's let's entertain a problem + + align:start position:0% +is uh let's let's entertain a problem + + + align:start position:0% +is uh let's let's entertain a problem +okay + + align:start position:0% +okay + + + align:start position:0% +okay +uh you've just graduated + + align:start position:0% +uh you've just graduated + + + align:start position:0% +uh you've just graduated +no you're not haven't just graduated + + align:start position:0% +no you're not haven't just graduated + + + align:start position:0% +no you're not haven't just graduated +you've graduated and you're working and + + align:start position:0% +you've graduated and you're working and + + + align:start position:0% +you've graduated and you're working and +you have + + align:start position:0% + + + + align:start position:0% + +sacrificed a lot + + align:start position:0% +sacrificed a lot + + + align:start position:0% +sacrificed a lot +and you've progressed + + align:start position:0% +and you've progressed + + + align:start position:0% +and you've progressed +in your company + + align:start position:0% + + + + align:start position:0% + +then + + align:start position:0% +then + + + align:start position:0% +then +your company + + align:start position:0% + + + + align:start position:0% + +is about ready to + + align:start position:0% +is about ready to + + + align:start position:0% +is about ready to +is competing for a contract + + align:start position:0% + + + + align:start position:0% + +uh let's say with the germans + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% + + + + align:start position:0% + +you're going to make the company's gonna + + align:start position:0% +you're going to make the company's gonna + + + align:start position:0% +you're going to make the company's gonna +make his pitch + + align:start position:0% +make his pitch + + + align:start position:0% +make his pitch +monday morning + + align:start position:0% +monday morning + + + align:start position:0% +monday morning +and you have to leave + + align:start position:0% + + + + align:start position:0% + +sunday night you get a call + + align:start position:0% +sunday night you get a call + + + align:start position:0% +sunday night you get a call +from your husband's + + align:start position:0% +from your husband's + + + align:start position:0% +from your husband's +um + + align:start position:0% + + + + align:start position:0% + +mother + + align:start position:0% +mother + + + align:start position:0% +mother +in + + align:start position:0% +in + + + align:start position:0% +in +arizona + + align:start position:0% +arizona + + + align:start position:0% +arizona +the kids are out visiting + + align:start position:0% +the kids are out visiting + + + align:start position:0% +the kids are out visiting +she's your husband says + + align:start position:0% +she's your husband says + + + align:start position:0% +she's your husband says +one of the kids got hit by a car + + align:start position:0% + + + + align:start position:0% + +uh the doctor says + + align:start position:0% +uh the doctor says + + + align:start position:0% +uh the doctor says +we don't know if the kid's gonna last + + align:start position:0% +we don't know if the kid's gonna last + + + align:start position:0% +we don't know if the kid's gonna last +another two days + + align:start position:0% +another two days + + + align:start position:0% +another two days +now do you go to that meeting on monday + + align:start position:0% +now do you go to that meeting on monday + + + align:start position:0% +now do you go to that meeting on monday +or do you go to arizona + + align:start position:0% + + + + align:start position:0% + +all right + + align:start position:0% + + + + align:start position:0% + +right well let me tell you what this + + align:start position:0% +right well let me tell you what this + + + align:start position:0% +right well let me tell you what this +heroic story is gonna + + align:start position:0% +heroic story is gonna + + + align:start position:0% +heroic story is gonna +how this heroic story is gonna help you + + align:start position:0% +how this heroic story is gonna help you + + + align:start position:0% +how this heroic story is gonna help you +with that decision + + align:start position:0% +with that decision + + + align:start position:0% +with that decision +the heroic story says + + align:start position:0% + + + + align:start position:0% + +that your conscious mind + + align:start position:0% + + + + align:start position:0% + +uh possesses + + align:start position:0% +uh possesses + + + align:start position:0% +uh possesses +does not possess all of the knowledge + + align:start position:0% +does not possess all of the knowledge + + + align:start position:0% +does not possess all of the knowledge +that your mind possesses + + align:start position:0% + + + + align:start position:0% + +your unconscious mind and i'm not + + align:start position:0% +your unconscious mind and i'm not + + + align:start position:0% +your unconscious mind and i'm not +talking about memories right now + + align:start position:0% +talking about memories right now + + + align:start position:0% +talking about memories right now +about parts of your conscious mind that + + align:start position:0% +about parts of your conscious mind that + + + align:start position:0% +about parts of your conscious mind that +are + + align:start position:0% +are + + + align:start position:0% +are +virtually permanent + + align:start position:0% +virtually permanent + + + align:start position:0% +virtually permanent +there are some truths that are hidden + + align:start position:0% +there are some truths that are hidden + + + align:start position:0% +there are some truths that are hidden +down in your unconscious + + align:start position:0% + + + + align:start position:0% + +and if you are able to get into a mythic + + align:start position:0% +and if you are able to get into a mythic + + + align:start position:0% +and if you are able to get into a mythic +state of mind + + align:start position:0% +state of mind + + + align:start position:0% +state of mind +then what you will be able to do + + align:start position:0% +then what you will be able to do + + + align:start position:0% +then what you will be able to do +is to go down in your unconscious and + + align:start position:0% +is to go down in your unconscious and + + + align:start position:0% +is to go down in your unconscious and +find out if one of those monsters down + + align:start position:0% +find out if one of those monsters down + + + align:start position:0% +find out if one of those monsters down +there + + align:start position:0% +there + + + align:start position:0% +there +needs to be killed + + align:start position:0% + + + + align:start position:0% + +now what kind of monster would be down + + align:start position:0% +now what kind of monster would be down + + + align:start position:0% +now what kind of monster would be down +there well i'll tell you one kind that + + align:start position:0% +there well i'll tell you one kind that + + + align:start position:0% +there well i'll tell you one kind that +would be down there your ambition + + align:start position:0% + + + + align:start position:0% + +because that your ambition is competing + + align:start position:0% +because that your ambition is competing + + + align:start position:0% +because that your ambition is competing +with that child + + align:start position:0% +with that child + + + align:start position:0% +with that child +now i was unfair because i made you all + + align:start position:0% +now i was unfair because i made you all + + + align:start position:0% +now i was unfair because i made you all +mothers + + align:start position:0% +mothers + + + align:start position:0% +mothers +but suppose + + align:start position:0% +but suppose + + + align:start position:0% +but suppose +uh + + align:start position:0% +uh + + + align:start position:0% +uh +it was some people + + align:start position:0% + + + + align:start position:0% + +that are gonna die if you don't go help + + align:start position:0% +that are gonna die if you don't go help + + + align:start position:0% +that are gonna die if you don't go help +them as opposed to going all right + + align:start position:0% + + + + align:start position:0% + +okay uh then you gotta then you gotta + + align:start position:0% +okay uh then you gotta then you gotta + + + align:start position:0% +okay uh then you gotta then you gotta +face that that demon down there that's + + align:start position:0% +face that that demon down there that's + + + align:start position:0% +face that that demon down there that's +your ambition + + align:start position:0% + + + + align:start position:0% + +and what you have got to do + + align:start position:0% +and what you have got to do + + + align:start position:0% +and what you have got to do +is to say + + align:start position:0% +is to say + + + align:start position:0% +is to say +that i would rather be dead to continue + + align:start position:0% +that i would rather be dead to continue + + + align:start position:0% +that i would rather be dead to continue +to live a life + + align:start position:0% +to live a life + + + align:start position:0% +to live a life +of not being able to deal with these + + align:start position:0% +of not being able to deal with these + + + align:start position:0% +of not being able to deal with these +decisions + + align:start position:0% +decisions + + + align:start position:0% +decisions +i got to deal with this maybe my + + align:start position:0% +i got to deal with this maybe my + + + align:start position:0% +i got to deal with this maybe my +ambition is good + + align:start position:0% +ambition is good + + + align:start position:0% +ambition is good +for me + + align:start position:0% +for me + + + align:start position:0% +for me +or maybe it's got to be killed but + + align:start position:0% +or maybe it's got to be killed but + + + align:start position:0% +or maybe it's got to be killed but +whatever it is i've got to face the + + align:start position:0% +whatever it is i've got to face the + + + align:start position:0% +whatever it is i've got to face the +devil + + align:start position:0% +devil + + + align:start position:0% +devil +and i am ready to die + + align:start position:0% +and i am ready to die + + + align:start position:0% +and i am ready to die +because that unconscious demon is lethal + + align:start position:0% +because that unconscious demon is lethal + + + align:start position:0% +because that unconscious demon is lethal +in the real world + + align:start position:0% + + + + align:start position:0% + +so if you decide that on somebody else's + + align:start position:0% +so if you decide that on somebody else's + + + align:start position:0% +so if you decide that on somebody else's +behalf + + align:start position:0% +behalf + + + align:start position:0% +behalf +you are willing to kill the demon and to + + align:start position:0% +you are willing to kill the demon and to + + + align:start position:0% +you are willing to kill the demon and to +bring the truth back + + align:start position:0% +bring the truth back + + + align:start position:0% +bring the truth back +to your conscious mind + + align:start position:0% +to your conscious mind + + + align:start position:0% +to your conscious mind +that's the best way to handle the + + align:start position:0% +that's the best way to handle the + + + align:start position:0% +that's the best way to handle the +problem whatever decision you come up + + align:start position:0% +problem whatever decision you come up + + + align:start position:0% +problem whatever decision you come up +with after that is the best you can do + + align:start position:0% +with after that is the best you can do + + + align:start position:0% +with after that is the best you can do +and the metaphor + + align:start position:0% +and the metaphor + + + align:start position:0% +and the metaphor +is in the heroic story + + align:start position:0% +is in the heroic story + + + align:start position:0% +is in the heroic story +so if you can get into the story to the + + align:start position:0% +so if you can get into the story to the + + + align:start position:0% +so if you can get into the story to the +point where you can get into possible's + + align:start position:0% +point where you can get into possible's + + + align:start position:0% +point where you can get into possible's +place and actually feel + + align:start position:0% +place and actually feel + + + align:start position:0% +place and actually feel +the possible feels and then get into + + align:start position:0% +the possible feels and then get into + + + align:start position:0% +the possible feels and then get into +some of these other stories where + + align:start position:0% +some of these other stories where + + + align:start position:0% +some of these other stories where +they're really killing dragons + + align:start position:0% +they're really killing dragons + + + align:start position:0% +they're really killing dragons +uh then what it does + + align:start position:0% +uh then what it does + + + align:start position:0% +uh then what it does +what what we know now + + align:start position:0% +what what we know now + + + align:start position:0% +what what we know now +um a thousand years later is that if you + + align:start position:0% +um a thousand years later is that if you + + + align:start position:0% +um a thousand years later is that if you +embrace those things seriously and if + + align:start position:0% +embrace those things seriously and if + + + align:start position:0% +embrace those things seriously and if +you really feel that you are possible + + align:start position:0% +you really feel that you are possible + + + align:start position:0% +you really feel that you are possible +in there + + align:start position:0% +in there + + + align:start position:0% +in there +then + + align:start position:0% +then + + + align:start position:0% +then +the wiring in your brain will change + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% +and + + + align:start position:0% +and +your 12 year old will start looking like + + align:start position:0% +your 12 year old will start looking like + + + align:start position:0% +your 12 year old will start looking like +a 14 year old + + align:start position:0% +a 14 year old + + + align:start position:0% +a 14 year old +not somebody who's going to be 18 year + + align:start position:0% +not somebody who's going to be 18 year + + + align:start position:0% +not somebody who's going to be 18 year +old still looking like 12 + + align:start position:0% +old still looking like 12 + + + align:start position:0% +old still looking like 12 +that your physiology if you're young + + align:start position:0% +that your physiology if you're young + + + align:start position:0% +that your physiology if you're young +enough will change + + align:start position:0% +enough will change + + + align:start position:0% +enough will change +you will grow up + + align:start position:0% + + + + align:start position:0% + +now + + align:start position:0% +now + + + align:start position:0% +now +uh + + align:start position:0% +uh + + + align:start position:0% +uh +ancient people + + align:start position:0% +ancient people + + + align:start position:0% +ancient people +uh and medieval people + + align:start position:0% +uh and medieval people + + + align:start position:0% +uh and medieval people +and early modern people do all of this + + align:start position:0% +and early modern people do all of this + + + align:start position:0% +and early modern people do all of this +before the science could prove any of it + + align:start position:0% +before the science could prove any of it + + + align:start position:0% +before the science could prove any of it +uh better stated + + align:start position:0% +uh better stated + + + align:start position:0% +uh better stated +better stated + + align:start position:0% +better stated + + + align:start position:0% +better stated +they were willing to commit to it + + align:start position:0% +they were willing to commit to it + + + align:start position:0% +they were willing to commit to it +regardless + + align:start position:0% + + + + align:start position:0% + +so when they had their young + + align:start position:0% +so when they had their young + + + align:start position:0% +so when they had their young +kids coming along + + align:start position:0% +kids coming along + + + align:start position:0% +kids coming along +particularly if they were afraid that + + align:start position:0% +particularly if they were afraid that + + + align:start position:0% +particularly if they were afraid that +the boys + + align:start position:0% +the boys + + + align:start position:0% +the boys +were going to have some free time + + align:start position:0% +were going to have some free time + + + align:start position:0% +were going to have some free time +oh i mean it's a nightmare if you got a + + align:start position:0% +oh i mean it's a nightmare if you got a + + + align:start position:0% +oh i mean it's a nightmare if you got a +16 year old + + align:start position:0% +16 year old + + + align:start position:0% +16 year old +on a saturday night + + align:start position:0% +on a saturday night + + + align:start position:0% +on a saturday night +i don't care how much you put into it + + align:start position:0% +i don't care how much you put into it + + + align:start position:0% +i don't care how much you put into it +that can be a bad night for you okay + + align:start position:0% +that can be a bad night for you okay + + + align:start position:0% +that can be a bad night for you okay +i know i was 16 years old + + align:start position:0% + + + + align:start position:0% + +but if you read these stories to them + + align:start position:0% + + + + align:start position:0% + +and if they can embrace them + + align:start position:0% +and if they can embrace them + + + align:start position:0% +and if they can embrace them +then that's a big help + + align:start position:0% +then that's a big help + + + align:start position:0% +then that's a big help +it's a big help + + align:start position:0% +it's a big help + + + align:start position:0% +it's a big help +uh some people have said that freud no + + align:start position:0% +uh some people have said that freud no + + + align:start position:0% +uh some people have said that freud no +matter what they what what others say + + align:start position:0% +matter what they what what others say + + + align:start position:0% +matter what they what what others say +that he brought + + align:start position:0% +that he brought + + + align:start position:0% +that he brought +the scientific method to the study of + + align:start position:0% +the scientific method to the study of + + + align:start position:0% +the scientific method to the study of +the mind what they really say is that + + align:start position:0% +the mind what they really say is that + + + align:start position:0% +the mind what they really say is that +freud was actually a + + align:start position:0% +freud was actually a + + + align:start position:0% +freud was actually a +pathologist + + align:start position:0% +pathologist + + + align:start position:0% +pathologist +because what he said was that that's the + + align:start position:0% +because what he said was that that's the + + + align:start position:0% +because what he said was that that's the +solution to your problem + + align:start position:0% +solution to your problem + + + align:start position:0% +solution to your problem +freud went one other step + + align:start position:0% +freud went one other step + + + align:start position:0% +freud went one other step +this is very significant and see if you + + align:start position:0% +this is very significant and see if you + + + align:start position:0% +this is very significant and see if you +can find it in any of these stories + + align:start position:0% +can find it in any of these stories + + + align:start position:0% +can find it in any of these stories +freud said that + + align:start position:0% +freud said that + + + align:start position:0% +freud said that +if you are an amateur fooling around + + align:start position:0% +if you are an amateur fooling around + + + align:start position:0% +if you are an amateur fooling around +with the unconscious + + align:start position:0% +with the unconscious + + + align:start position:0% +with the unconscious +you're unconscious or anybody else's + + align:start position:0% +you're unconscious or anybody else's + + + align:start position:0% +you're unconscious or anybody else's +you may release the demon + + align:start position:0% +you may release the demon + + + align:start position:0% +you may release the demon +but unless you make + + align:start position:0% +but unless you make + + + align:start position:0% +but unless you make +the demon morally acceptable to your + + align:start position:0% +the demon morally acceptable to your + + + align:start position:0% +the demon morally acceptable to your +conscious mind + + align:start position:0% +conscious mind + + + align:start position:0% +conscious mind +the demon will get up there and run you + + align:start position:0% +the demon will get up there and run you + + + align:start position:0% +the demon will get up there and run you +to the insane side + + align:start position:0% + + + + align:start position:0% + +and freud talked about that in terms of + + align:start position:0% + + + + align:start position:0% + +of + + align:start position:0% +of + + + align:start position:0% +of +the + + align:start position:0% +the + + + align:start position:0% +the +competition + + align:start position:0% +competition + + + align:start position:0% +competition +the boys have with the father + + align:start position:0% +the boys have with the father + + + align:start position:0% +the boys have with the father +and + + align:start position:0% +and + + + align:start position:0% +and +wanting to kill the father and take the + + align:start position:0% +wanting to kill the father and take the + + + align:start position:0% +wanting to kill the father and take the +father's place with the mother + + align:start position:0% + + + + align:start position:0% + +uh + + align:start position:0% +uh + + + align:start position:0% +uh +and + + align:start position:0% +and + + + align:start position:0% +and +mary shelley made a big deal out of it + + align:start position:0% +mary shelley made a big deal out of it + + + align:start position:0% +mary shelley made a big deal out of it +with frankenstein + + align:start position:0% +with frankenstein + + + align:start position:0% +with frankenstein +because what did frankenstein want to do + + align:start position:0% +because what did frankenstein want to do + + + align:start position:0% +because what did frankenstein want to do +to kill his maker + + align:start position:0% + + + + align:start position:0% + +you know down his wire down in the brain + + align:start position:0% +you know down his wire down in the brain + + + align:start position:0% +you know down his wire down in the brain +freud said if that's the truth + + align:start position:0% +freud said if that's the truth + + + align:start position:0% +freud said if that's the truth +then that's a hard thing to justify + + align:start position:0% +then that's a hard thing to justify + + + align:start position:0% +then that's a hard thing to justify +morally + + align:start position:0% +morally + + + align:start position:0% +morally +so it's best left down there unless you + + align:start position:0% +so it's best left down there unless you + + + align:start position:0% +so it's best left down there unless you +can find a way to bring it up moral + + align:start position:0% +can find a way to bring it up moral + + + align:start position:0% +can find a way to bring it up moral +so mythology is supposed to do all that + + align:start position:0% +so mythology is supposed to do all that + + + align:start position:0% +so mythology is supposed to do all that +now let's talk about how + + align:start position:0% +now let's talk about how + + + align:start position:0% +now let's talk about how +this thing fits into this class + + align:start position:0% + + + + align:start position:0% + +if you want to solve an ethical problem + + align:start position:0% +if you want to solve an ethical problem + + + align:start position:0% +if you want to solve an ethical problem +and you want to solve it by using + + align:start position:0% +and you want to solve it by using + + + align:start position:0% +and you want to solve it by using +the method of virtues + + align:start position:0% +the method of virtues + + + align:start position:0% +the method of virtues +but you don't want to deal you don't + + align:start position:0% +but you don't want to deal you don't + + + align:start position:0% +but you don't want to deal you don't +want the virtue the list of virtues that + + align:start position:0% +want the virtue the list of virtues that + + + align:start position:0% +want the virtue the list of virtues that +plague or any of those people have + + align:start position:0% +plague or any of those people have + + + align:start position:0% +plague or any of those people have +but you want to find a character like i + + align:start position:0% +but you want to find a character like i + + + align:start position:0% +but you want to find a character like i +did + + align:start position:0% +did + + + align:start position:0% +did +with my first day on an engineering job + + align:start position:0% +with my first day on an engineering job + + + align:start position:0% +with my first day on an engineering job +put that character in your place work + + align:start position:0% +put that character in your place work + + + align:start position:0% +put that character in your place work +the character through it and then + + align:start position:0% +the character through it and then + + + align:start position:0% +the character through it and then +imitate to some extent that character + + align:start position:0% +imitate to some extent that character + + + align:start position:0% +imitate to some extent that character +the question is what character to choose + + align:start position:0% + + + + align:start position:0% + +it's not simply a matter of choosing a + + align:start position:0% +it's not simply a matter of choosing a + + + align:start position:0% +it's not simply a matter of choosing a +good person + + align:start position:0% +good person + + + align:start position:0% +good person +because in the end what you want + + align:start position:0% +because in the end what you want + + + align:start position:0% +because in the end what you want +is to still have your job + + align:start position:0% + + + + align:start position:0% + +see + + align:start position:0% +see + + + align:start position:0% +see +all right + + align:start position:0% +all right + + + align:start position:0% +all right +you might not you have to be prepared to + + align:start position:0% +you might not you have to be prepared to + + + align:start position:0% +you might not you have to be prepared to +lose it + + align:start position:0% +lose it + + + align:start position:0% +lose it +but what you want in the end + + align:start position:0% +but what you want in the end + + + align:start position:0% +but what you want in the end +is to have somebody on your side + + align:start position:0% +is to have somebody on your side + + + align:start position:0% +is to have somebody on your side +okay + + align:start position:0% +okay + + + align:start position:0% +okay +now what what the at the idea of the + + align:start position:0% +now what what the at the idea of the + + + align:start position:0% +now what what the at the idea of the +mythic story is that the mythic story + + align:start position:0% +mythic story is that the mythic story + + + align:start position:0% +mythic story is that the mythic story +provides a hero + + align:start position:0% +provides a hero + + + align:start position:0% +provides a hero +that is uh not only a hero to you but as + + align:start position:0% +that is uh not only a hero to you but as + + + align:start position:0% +that is uh not only a hero to you but as +a hero of people + + align:start position:0% + + + + align:start position:0% + +and why is that because of the long + + align:start position:0% +and why is that because of the long + + + align:start position:0% +and why is that because of the long +story i just gave it it it + + align:start position:0% +story i just gave it it it + + + align:start position:0% +story i just gave it it it +it it's another thing that sort of wired + + align:start position:0% +it it's another thing that sort of wired + + + align:start position:0% +it it's another thing that sort of wired +into the brain that after a while + + align:start position:0% +into the brain that after a while + + + align:start position:0% +into the brain that after a while +um + + align:start position:0% +um + + + align:start position:0% +um +people began to see from these stories + + align:start position:0% +people began to see from these stories + + + align:start position:0% +people began to see from these stories +that + + align:start position:0% +that + + + align:start position:0% +that +uh you know there's there's something of + + align:start position:0% +uh you know there's there's something of + + + align:start position:0% +uh you know there's there's something of +me + + align:start position:0% +me + + + align:start position:0% +me +in these heroes + + align:start position:0% + + + + align:start position:0% + +why is that all right + + align:start position:0% +why is that all right + + + align:start position:0% +why is that all right +um + + align:start position:0% + + + + align:start position:0% + +all right this is where gestalt + + align:start position:0% + + + + align:start position:0% + +and let's take the neck or cube again + + align:start position:0% + + + + align:start position:0% + +your brain actually sees is a + + align:start position:0% +your brain actually sees is a + + + align:start position:0% +your brain actually sees is a +three-dimensional figure + + align:start position:0% + + + + align:start position:0% + +what's up there's + + align:start position:0% +what's up there's + + + align:start position:0% +what's up there's +12 lines on a flat + + align:start position:0% +12 lines on a flat + + + align:start position:0% +12 lines on a flat +board + + align:start position:0% +board + + + align:start position:0% +board +okay + + align:start position:0% +okay + + + align:start position:0% +okay +um + + align:start position:0% +um + + + align:start position:0% +um +when you're sitting around with your + + align:start position:0% +when you're sitting around with your + + + align:start position:0% +when you're sitting around with your +family + + align:start position:0% + + + + align:start position:0% + +uh is the one person that gets up to + + align:start position:0% +uh is the one person that gets up to + + + align:start position:0% +uh is the one person that gets up to +sort of like + + align:start position:0% +sort of like + + + align:start position:0% +sort of like +represents + + align:start position:0% +represents + + + align:start position:0% +represents +you know your family you know + + align:start position:0% +you know your family you know + + + align:start position:0% +you know your family you know +uh + + align:start position:0% +uh + + + align:start position:0% +uh +is there such a thing as an mit person + + align:start position:0% + + + + align:start position:0% + +can you go to the airport + + align:start position:0% + + + + align:start position:0% + +uh + + align:start position:0% +uh + + + align:start position:0% +uh +and say well there are 400 students out + + align:start position:0% +and say well there are 400 students out + + + align:start position:0% +and say well there are 400 students out +here but + + align:start position:0% +here but + + + align:start position:0% +here but +that one is probably for them + + align:start position:0% + + + + align:start position:0% + +doesn't matter if you're right or wrong + + align:start position:0% +doesn't matter if you're right or wrong + + + align:start position:0% +doesn't matter if you're right or wrong +the point is you got a picture in your + + align:start position:0% +the point is you got a picture in your + + + align:start position:0% +the point is you got a picture in your +mind + + align:start position:0% +mind + + + align:start position:0% +mind +did i ever tell you a story about the + + align:start position:0% +did i ever tell you a story about the + + + align:start position:0% +did i ever tell you a story about the +old uh about the old blues that yale + + align:start position:0% +old uh about the old blues that yale + + + align:start position:0% +old uh about the old blues that yale +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +i was chair of faculty senate we were we + + align:start position:0% +i was chair of faculty senate we were we + + + align:start position:0% +i was chair of faculty senate we were we +had just gotten the constitution + + align:start position:0% +had just gotten the constitution + + + align:start position:0% +had just gotten the constitution +approved where we could get faculty + + align:start position:0% +approved where we could get faculty + + + align:start position:0% +approved where we could get faculty +members on the board of trustees the + + align:start position:0% +members on the board of trustees the + + + align:start position:0% +members on the board of trustees the +question was what kind of faculty member + + align:start position:0% +question was what kind of faculty member + + + align:start position:0% +question was what kind of faculty member +we want + + align:start position:0% +we want + + + align:start position:0% +we want +you get somebody that's quote unquote + + align:start position:0% +you get somebody that's quote unquote + + + align:start position:0% +you get somebody that's quote unquote +too scholarly the trust the board won't + + align:start position:0% +too scholarly the trust the board won't + + + align:start position:0% +too scholarly the trust the board won't +understand + + align:start position:0% + + + + align:start position:0% + +uh you get somebody who's too + + align:start position:0% +uh you get somebody who's too + + + align:start position:0% +uh you get somebody who's too +business-like and he won't reflect the + + align:start position:0% +business-like and he won't reflect the + + + align:start position:0% +business-like and he won't reflect the +rest or she won't reflect the rest of + + align:start position:0% +rest or she won't reflect the rest of + + + align:start position:0% +rest or she won't reflect the rest of +so what do you do how do you deal with + + align:start position:0% +so what do you do how do you deal with + + + align:start position:0% +so what do you do how do you deal with +that problem there was one faculty + + align:start position:0% +that problem there was one faculty + + + align:start position:0% +that problem there was one faculty +member there who + + align:start position:0% +member there who + + + align:start position:0% +member there who +got his law degree from jail and he said + + align:start position:0% +got his law degree from jail and he said + + + align:start position:0% +got his law degree from jail and he said +well look why don't you call up to the + + align:start position:0% +well look why don't you call up to the + + + align:start position:0% +well look why don't you call up to the +call up to the president's office and uh + + align:start position:0% +call up to the president's office and uh + + + align:start position:0% +call up to the president's office and uh +ask for the person who staffs the uh + + align:start position:0% +ask for the person who staffs the uh + + + align:start position:0% +ask for the person who staffs the uh +trustee + + align:start position:0% +trustee + + + align:start position:0% +trustee +and when you get the person on the phone + + align:start position:0% +and when you get the person on the phone + + + align:start position:0% +and when you get the person on the phone +asking what an old blue is i said what's + + align:start position:0% +asking what an old blue is i said what's + + + align:start position:0% +asking what an old blue is i said what's +an it's a drastic person okay so i call + + align:start position:0% +an it's a drastic person okay so i call + + + align:start position:0% +an it's a drastic person okay so i call +them + + align:start position:0% +them + + + align:start position:0% +them +they gave me the staff person for the + + align:start position:0% +they gave me the staff person for the + + + align:start position:0% +they gave me the staff person for the +board and i said what's an old blue + + align:start position:0% +board and i said what's an old blue + + + align:start position:0% +board and i said what's an old blue +and she said an old blue is a member of + + align:start position:0% +and she said an old blue is a member of + + + align:start position:0% +and she said an old blue is a member of +the faculty who looks like yale + + align:start position:0% + + + + align:start position:0% + +i understood that i mean it was abstract + + align:start position:0% +i understood that i mean it was abstract + + + align:start position:0% +i understood that i mean it was abstract +yeah okay + + align:start position:0% +yeah okay + + + align:start position:0% +yeah okay +uh and we concluded in the end they said + + align:start position:0% +uh and we concluded in the end they said + + + align:start position:0% +uh and we concluded in the end they said +they come into board meetings the board + + align:start position:0% +they come into board meetings the board + + + align:start position:0% +they come into board meetings the board +meet the board + + align:start position:0% +meet the board + + + align:start position:0% +meet the board +by some yale tradition + + align:start position:0% +by some yale tradition + + + align:start position:0% +by some yale tradition +is able to pick out who the old blues + + align:start position:0% +is able to pick out who the old blues + + + align:start position:0% +is able to pick out who the old blues +are + + align:start position:0% +are + + + align:start position:0% +are +and the board brings them into the board + + align:start position:0% +and the board brings them into the board + + + align:start position:0% +and the board brings them into the board +meeting + + align:start position:0% +meeting + + + align:start position:0% +meeting +and here's what really happens according + + align:start position:0% +and here's what really happens according + + + align:start position:0% +and here's what really happens according +to that conversation + + align:start position:0% +to that conversation + + + align:start position:0% +to that conversation +that 95 of the time the board is talking + + align:start position:0% +that 95 of the time the board is talking + + + align:start position:0% +that 95 of the time the board is talking +about what yale lives for + + align:start position:0% +about what yale lives for + + + align:start position:0% +about what yale lives for +but when they want to make a decision + + align:start position:0% +but when they want to make a decision + + + align:start position:0% +but when they want to make a decision +where they can gain a lot + + align:start position:0% +where they can gain a lot + + + align:start position:0% +where they can gain a lot +maybe they want to know what yale is + + align:start position:0% +maybe they want to know what yale is + + + align:start position:0% +maybe they want to know what yale is +willing to die for + + align:start position:0% +willing to die for + + + align:start position:0% +willing to die for +then they turn to the old blue should we + + align:start position:0% +then they turn to the old blue should we + + + align:start position:0% +then they turn to the old blue should we +take this take on this project + + align:start position:0% +take this take on this project + + + align:start position:0% +take this take on this project +should we have a course in here on islam + + align:start position:0% +should we have a course in here on islam + + + align:start position:0% +should we have a course in here on islam +uh should we have um + + align:start position:0% +uh should we have um + + + align:start position:0% +uh should we have um +uh jerry falwell on the faculty + + align:start position:0% +uh jerry falwell on the faculty + + + align:start position:0% +uh jerry falwell on the faculty +they look to the old blues and the + + align:start position:0% +they look to the old blues and the + + + align:start position:0% +they look to the old blues and the +answer is not right or wrong answers is + + align:start position:0% +answer is not right or wrong answers is + + + align:start position:0% +answer is not right or wrong answers is +this yeah + + align:start position:0% +this yeah + + + align:start position:0% +this yeah +if we do this will we have yale at the + + align:start position:0% +if we do this will we have yale at the + + + align:start position:0% +if we do this will we have yale at the +end + + align:start position:0% +end + + + align:start position:0% +end +okay + + align:start position:0% +okay + + + align:start position:0% +okay +well that's a good start of yale + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% +and + + + align:start position:0% +and +this tradition i'm talking about is + + align:start position:0% +this tradition i'm talking about is + + + align:start position:0% +this tradition i'm talking about is +yale's mythology + + align:start position:0% +yale's mythology + + + align:start position:0% +yale's mythology +mythology will give you these old blues + + align:start position:0% +mythology will give you these old blues + + + align:start position:0% +mythology will give you these old blues +for a culture + + align:start position:0% +for a culture + + + align:start position:0% +for a culture +and if an old blue is representative of + + align:start position:0% +and if an old blue is representative of + + + align:start position:0% +and if an old blue is representative of +the whole + + align:start position:0% +the whole + + + align:start position:0% +the whole +then the old the old blue is + + align:start position:0% +then the old the old blue is + + + align:start position:0% +then the old the old blue is +has a part of each of us in + + align:start position:0% +has a part of each of us in + + + align:start position:0% +has a part of each of us in +him or her + + align:start position:0% +him or her + + + align:start position:0% +him or her +and once she has done whatever she has + + align:start position:0% +and once she has done whatever she has + + + align:start position:0% +and once she has done whatever she has +done no matter how bad it is + + align:start position:0% +done no matter how bad it is + + + align:start position:0% +done no matter how bad it is +we all have a tendency to say well + + align:start position:0% +we all have a tendency to say well + + + align:start position:0% +we all have a tendency to say well +maybe she needs to be punished but let's + + align:start position:0% +maybe she needs to be punished but let's + + + align:start position:0% +maybe she needs to be punished but let's +not be too harsh + + align:start position:0% +not be too harsh + + + align:start position:0% +not be too harsh +you know i mean i might have done that + + align:start position:0% +you know i mean i might have done that + + + align:start position:0% +you know i mean i might have done that +or you know + + align:start position:0% +or you know + + + align:start position:0% +or you know +we are decent people here but this is + + align:start position:0% +we are decent people here but this is + + + align:start position:0% +we are decent people here but this is +the best it gets with our + + align:start position:0% + + + + align:start position:0% + +family so if you pull out a cultural + + align:start position:0% +family so if you pull out a cultural + + + align:start position:0% +family so if you pull out a cultural +hero and imitate a cultural hero + + align:start position:0% +hero and imitate a cultural hero + + + align:start position:0% +hero and imitate a cultural hero +uh my argument has been and i'm not + + align:start position:0% +uh my argument has been and i'm not + + + align:start position:0% +uh my argument has been and i'm not +alone in this + + align:start position:0% +alone in this + + + align:start position:0% +alone in this +that whatever you do in the end + + align:start position:0% +that whatever you do in the end + + + align:start position:0% +that whatever you do in the end +uh and no matter what where + + align:start position:0% +uh and no matter what where + + + align:start position:0% +uh and no matter what where +whether the whether + + align:start position:0% +whether the whether + + + align:start position:0% +whether the whether +they want to punish you for it + + align:start position:0% +they want to punish you for it + + + align:start position:0% +they want to punish you for it +it will be a tendency + + align:start position:0% +it will be a tendency + + + align:start position:0% +it will be a tendency +for them to + + align:start position:0% +for them to + + + align:start position:0% +for them to +to side with you or to forgive you or to + + align:start position:0% +to side with you or to forgive you or to + + + align:start position:0% +to side with you or to forgive you or to +see the point of what you did or + + align:start position:0% +see the point of what you did or + + + align:start position:0% +see the point of what you did or +something + + align:start position:0% + + + + align:start position:0% + +yes + + align:start position:0% + + + + align:start position:0% + +but it's really tough + + align:start position:0% + + + + align:start position:0% + +and i wonder if that's different like a + + align:start position:0% +and i wonder if that's different like a + + + align:start position:0% +and i wonder if that's different like a +cultural bureau to me would be someone + + align:start position:0% +cultural bureau to me would be someone + + + align:start position:0% +cultural bureau to me would be someone +who + + align:start position:0% +who + + + align:start position:0% +who +has faced decisions + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +uh first of all uh you hit a very very a + + align:start position:0% +uh first of all uh you hit a very very a + + + align:start position:0% +uh first of all uh you hit a very very a +very um important nerve and that is that + + align:start position:0% +very um important nerve and that is that + + + align:start position:0% +very um important nerve and that is that +uh there's generational differences + + align:start position:0% +uh there's generational differences + + + align:start position:0% +uh there's generational differences +uh + + align:start position:0% +uh + + + align:start position:0% +uh +and + + align:start position:0% +and + + + align:start position:0% +and +so the question is why is it + + align:start position:0% +so the question is why is it + + + align:start position:0% +so the question is why is it +that possible meant so much to me + + align:start position:0% +that possible meant so much to me + + + align:start position:0% +that possible meant so much to me +he was i was not in his generation + + align:start position:0% +he was i was not in his generation + + + align:start position:0% +he was i was not in his generation +you know + + align:start position:0% +you know + + + align:start position:0% +you know +um + + align:start position:0% +um + + + align:start position:0% +um +and the key word + + align:start position:0% +and the key word + + + align:start position:0% +and the key word +in the end + + align:start position:0% + + + + align:start position:0% + +is metaphor + + align:start position:0% + + + + align:start position:0% + +because i did now now listen to me + + align:start position:0% +because i did now now listen to me + + + align:start position:0% +because i did now now listen to me +carefully because i want to choose my + + align:start position:0% +carefully because i want to choose my + + + align:start position:0% +carefully because i want to choose my +words properly here because if i mess up + + align:start position:0% +words properly here because if i mess up + + + align:start position:0% +words properly here because if i mess up +i could really throw everybody off + + align:start position:0% +i could really throw everybody off + + + align:start position:0% +i could really throw everybody off +all right + + align:start position:0% + + + + align:start position:0% + +when i had to make that decision on my + + align:start position:0% +when i had to make that decision on my + + + align:start position:0% +when i had to make that decision on my +first day + + align:start position:0% +first day + + + align:start position:0% +first day +as an engineer + + align:start position:0% + + + + align:start position:0% + +i didn't see any difference between + + align:start position:0% +i didn't see any difference between + + + align:start position:0% +i didn't see any difference between +parcel and my uncle rook + + align:start position:0% + + + + align:start position:0% + +campbell says that the + + align:start position:0% +campbell says that the + + + align:start position:0% +campbell says that the +hero's journey + + align:start position:0% +hero's journey + + + align:start position:0% +hero's journey +has this path we just went through it + + align:start position:0% +has this path we just went through it + + + align:start position:0% +has this path we just went through it +first of all you hear a call + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +that's really your unconscious trying to + + align:start position:0% +that's really your unconscious trying to + + + align:start position:0% +that's really your unconscious trying to +say look you better get down here + + align:start position:0% +say look you better get down here + + + align:start position:0% +say look you better get down here +uh you hear a call you don't really want + + align:start position:0% +uh you hear a call you don't really want + + + align:start position:0% +uh you hear a call you don't really want +to do it because somehow you know that + + align:start position:0% +to do it because somehow you know that + + + align:start position:0% +to do it because somehow you know that +this thing can be lethal + + align:start position:0% + + + + align:start position:0% + +but some + + align:start position:0% +but some + + + align:start position:0% +but some +somebody else makes the case that if you + + align:start position:0% +somebody else makes the case that if you + + + align:start position:0% +somebody else makes the case that if you +don't go somebody else is going to + + align:start position:0% +don't go somebody else is going to + + + align:start position:0% +don't go somebody else is going to +suffer so you got to go + + align:start position:0% + + + + align:start position:0% + +so the first thing is to hear the call + + align:start position:0% +so the first thing is to hear the call + + + align:start position:0% +so the first thing is to hear the call +the second thing is the separation you + + align:start position:0% +the second thing is the separation you + + + align:start position:0% +the second thing is the separation you +have got to go away from the comfort + + align:start position:0% +have got to go away from the comfort + + + align:start position:0% +have got to go away from the comfort +zone + + align:start position:0% +zone + + + align:start position:0% +zone +and into the unknown + + align:start position:0% +and into the unknown + + + align:start position:0% +and into the unknown +and the fabulous that's very important + + align:start position:0% +and the fabulous that's very important + + + align:start position:0% +and the fabulous that's very important +fabulous fabulous not fabulous in terms + + align:start position:0% +fabulous fabulous not fabulous in terms + + + align:start position:0% +fabulous fabulous not fabulous in terms +of + + align:start position:0% +of + + + align:start position:0% +of +of uh + + align:start position:0% +of uh + + + align:start position:0% +of uh +peacock feathers fabulous in terms of + + align:start position:0% +peacock feathers fabulous in terms of + + + align:start position:0% +peacock feathers fabulous in terms of +fable + + align:start position:0% +fable + + + align:start position:0% +fable +that there are things that you're going + + align:start position:0% +that there are things that you're going + + + align:start position:0% +that there are things that you're going +to encounter that are not of this + + align:start position:0% +to encounter that are not of this + + + align:start position:0% +to encounter that are not of this +conscious earth they're the demons in + + align:start position:0% +conscious earth they're the demons in + + + align:start position:0% +conscious earth they're the demons in +your country + + align:start position:0% +your country + + + align:start position:0% +your country +you got to slay a dragon because that's + + align:start position:0% +you got to slay a dragon because that's + + + align:start position:0% +you got to slay a dragon because that's +a that's a real thing in your + + align:start position:0% +a that's a real thing in your + + + align:start position:0% +a that's a real thing in your +unconscious + + align:start position:0% +unconscious + + + align:start position:0% +unconscious +and then when you slay the dragon you + + align:start position:0% +and then when you slay the dragon you + + + align:start position:0% +and then when you slay the dragon you +have to bring back something like the + + align:start position:0% +have to bring back something like the + + + align:start position:0% +have to bring back something like the +truth + + align:start position:0% +truth + + + align:start position:0% +truth +that's the holy grail + + align:start position:0% +that's the holy grail + + + align:start position:0% +that's the holy grail +you've got to bring the grail back and + + align:start position:0% +you've got to bring the grail back and + + + align:start position:0% +you've got to bring the grail back and +what do you do with the grail when you + + align:start position:0% +what do you do with the grail when you + + + align:start position:0% +what do you do with the grail when you +get back you share it with everybody + + align:start position:0% + + + + align:start position:0% + +okay so those that's the pattern of the + + align:start position:0% +okay so those that's the pattern of the + + + align:start position:0% +okay so those that's the pattern of the +hero's journey + + align:start position:0% +hero's journey + + + align:start position:0% +hero's journey +look at roy why was roy a + + align:start position:0% +look at roy why was roy a + + + align:start position:0% +look at roy why was roy a +hero well + + align:start position:0% +hero well + + + align:start position:0% +hero well +when they got back + + align:start position:0% + + + + align:start position:0% + +home found out that all their parents + + align:start position:0% +home found out that all their parents + + + align:start position:0% +home found out that all their parents +were dead + + align:start position:0% + + + + align:start position:0% + +then + + align:start position:0% +then + + + align:start position:0% +then +they heard a call to do something + + align:start position:0% +they heard a call to do something + + + align:start position:0% +they heard a call to do something +for the children + + align:start position:0% +for the children + + + align:start position:0% +for the children +but it wasn't staying there + + align:start position:0% +but it wasn't staying there + + + align:start position:0% +but it wasn't staying there +working so they had to go out + + align:start position:0% + + + + align:start position:0% + +uh when they got down to oberlin that + + align:start position:0% +uh when they got down to oberlin that + + + align:start position:0% +uh when they got down to oberlin that +was just like being in a dream world for + + align:start position:0% +was just like being in a dream world for + + + align:start position:0% +was just like being in a dream world for +them + + align:start position:0% +them + + + align:start position:0% +them +i've heard them talk about it + + align:start position:0% +i've heard them talk about it + + + align:start position:0% +i've heard them talk about it +and + + align:start position:0% +and + + + align:start position:0% +and +when they got their degrees what did + + align:start position:0% +when they got their degrees what did + + + align:start position:0% +when they got their degrees what did +they do with the degrees they didn't go + + align:start position:0% +they do with the degrees they didn't go + + + align:start position:0% +they do with the degrees they didn't go +out and get a big job they brought the + + align:start position:0% +out and get a big job they brought the + + + align:start position:0% +out and get a big job they brought the +degree back home + + align:start position:0% +degree back home + + + align:start position:0% +degree back home +to help the others get out + + align:start position:0% +to help the others get out + + + align:start position:0% +to help the others get out +that was their holy grail it's the same + + align:start position:0% +that was their holy grail it's the same + + + align:start position:0% +that was their holy grail it's the same +thing + + align:start position:0% + + + + align:start position:0% + +so uh what you've got to do + + align:start position:0% +so uh what you've got to do + + + align:start position:0% +so uh what you've got to do +is to look around you and find somebody + + align:start position:0% +is to look around you and find somebody + + + align:start position:0% +is to look around you and find somebody +you know now you don't have to know them + + align:start position:0% +you know now you don't have to know them + + + align:start position:0% +you know now you don't have to know them +personally + + align:start position:0% +personally + + + align:start position:0% +personally +but find somebody you know who has had + + align:start position:0% +but find somebody you know who has had + + + align:start position:0% +but find somebody you know who has had +that same experience + + align:start position:0% +that same experience + + + align:start position:0% +that same experience +they don't have to be perfect people + + align:start position:0% + + + + align:start position:0% + +right but if they have had that + + align:start position:0% +right but if they have had that + + + align:start position:0% +right but if they have had that +experience + + align:start position:0% +experience + + + align:start position:0% +experience +and they are heroes in the sense that + + align:start position:0% +and they are heroes in the sense that + + + align:start position:0% +and they are heroes in the sense that +their + + align:start position:0% +their + + + align:start position:0% +their +beautiful thing about these things is + + align:start position:0% +beautiful thing about these things is + + + align:start position:0% +beautiful thing about these things is +they don't hide as we just discussed + + align:start position:0% +they don't hide as we just discussed + + + align:start position:0% +they don't hide as we just discussed +the the negative sides of these people's + + align:start position:0% +the the negative sides of these people's + + + align:start position:0% +the the negative sides of these people's +characters i mean when you find out what + + align:start position:0% +characters i mean when you find out what + + + align:start position:0% +characters i mean when you find out what +is relevant in them that's heroic + + align:start position:0% +is relevant in them that's heroic + + + align:start position:0% +is relevant in them that's heroic +put them in one of your situations + + align:start position:0% +put them in one of your situations + + + align:start position:0% +put them in one of your situations +do your best or do what you think is + + align:start position:0% +do your best or do what you think is + + + align:start position:0% +do your best or do what you think is +right in terms of how you unless you can + + align:start position:0% +right in terms of how you unless you can + + + align:start position:0% +right in terms of how you unless you can +follow them + + align:start position:0% +follow them + + + align:start position:0% +follow them +then once you have done it everybody + + align:start position:0% +then once you have done it everybody + + + align:start position:0% +then once you have done it everybody +else even if it's only on an unconscious + + align:start position:0% +else even if it's only on an unconscious + + + align:start position:0% +else even if it's only on an unconscious +level + + align:start position:0% +level + + + align:start position:0% +level +will see some sense in it and have some + + align:start position:0% +will see some sense in it and have some + + + align:start position:0% +will see some sense in it and have some +compassion for you why you did it + + align:start position:0% +compassion for you why you did it + + + align:start position:0% +compassion for you why you did it +and we'll be inclined to say well you + + align:start position:0% +and we'll be inclined to say well you + + + align:start position:0% +and we'll be inclined to say well you +know + + align:start position:0% +know + + + align:start position:0% +know +that's as good as get better as it gets + + align:start position:0% +that's as good as get better as it gets + + + align:start position:0% +that's as good as get better as it gets +with us + + align:start position:0% + + + + align:start position:0% + +and uh you'll be the kind that if they + + align:start position:0% +and uh you'll be the kind that if they + + + align:start position:0% +and uh you'll be the kind that if they +sent the prison you get your own job + + align:start position:0% +sent the prison you get your own job + + + align:start position:0% +sent the prison you get your own job +back when you get out + + align:start position:0% +back when you get out + + + align:start position:0% +back when you get out +you see what i'm saying + + align:start position:0% + + + + align:start position:0% + +uh + + align:start position:0% +uh + + + align:start position:0% +uh +you'll be + + align:start position:0% +you'll be + + + align:start position:0% +you'll be +uh like john brown at uh + + align:start position:0% +uh like john brown at uh + + + align:start position:0% +uh like john brown at uh +rugby was it rugby john john brown + + align:start position:0% +rugby was it rugby john john brown + + + align:start position:0% +rugby was it rugby john john brown +school days was at rugby i'm talking + + align:start position:0% +school days was at rugby i'm talking + + + align:start position:0% +school days was at rugby i'm talking +about + + align:start position:0% +about + + + align:start position:0% +about +this story about this american that goes + + align:start position:0% +this story about this american that goes + + + align:start position:0% +this story about this american that goes +to + + align:start position:0% +to + + + align:start position:0% +to +one of the british schools and he does + + align:start position:0% +one of the british schools and he does + + + align:start position:0% +one of the british schools and he does +something very heroic but he gets + + align:start position:0% +something very heroic but he gets + + + align:start position:0% +something very heroic but he gets +sent down for it gets kicked out of + + align:start position:0% +sent down for it gets kicked out of + + + align:start position:0% +sent down for it gets kicked out of +school for it + + align:start position:0% +school for it + + + align:start position:0% +school for it +coal + + align:start position:0% +coal + + + align:start position:0% +coal +yeah it's uh + + align:start position:0% +yeah it's uh + + + align:start position:0% +yeah it's uh +oxford it's it's uh john brown at oxford + + align:start position:0% +oxford it's it's uh john brown at oxford + + + align:start position:0% +oxford it's it's uh john brown at oxford +i think it's the name of it well anyway + + align:start position:0% +i think it's the name of it well anyway + + + align:start position:0% +i think it's the name of it well anyway +what happens is he gets sent down for it + + align:start position:0% +what happens is he gets sent down for it + + + align:start position:0% +what happens is he gets sent down for it +but when he's in the carriage leaving + + align:start position:0% +but when he's in the carriage leaving + + + align:start position:0% +but when he's in the carriage leaving +oxford on the way to the um + + align:start position:0% +oxford on the way to the um + + + align:start position:0% +oxford on the way to the um +to the uh port where he gets the boat + + align:start position:0% +to the uh port where he gets the boat + + + align:start position:0% +to the uh port where he gets the boat +home + + align:start position:0% +home + + + align:start position:0% +home +all of the oxford students out there + + align:start position:0% +all of the oxford students out there + + + align:start position:0% +all of the oxford students out there +cheering him on + + align:start position:0% + + + + align:start position:0% + +that's the kind of hero i'm talking + + align:start position:0% +that's the kind of hero i'm talking + + + align:start position:0% +that's the kind of hero i'm talking +about if you gotta go + + align:start position:0% +about if you gotta go + + + align:start position:0% +about if you gotta go +you're still they still will treat you + + align:start position:0% +you're still they still will treat you + + + align:start position:0% +you're still they still will treat you +like + + align:start position:0% +like + + + align:start position:0% +like +you think what you do is + + align:start position:0% +you think what you do is + + + align:start position:0% +you think what you do is +well as good as it gets + + align:start position:0% +well as good as it gets + + + align:start position:0% +well as good as it gets +all right so um my point is that we can + + align:start position:0% +all right so um my point is that we can + + + align:start position:0% +all right so um my point is that we can +bring + + align:start position:0% +bring + + + align:start position:0% +bring +virtue ethics back + + align:start position:0% + + + + align:start position:0% + +but + + align:start position:0% +but + + + align:start position:0% +but +mythology + + align:start position:0% +mythology + + + align:start position:0% +mythology +is the way to go and if you do mythology + + align:start position:0% +is the way to go and if you do mythology + + + align:start position:0% +is the way to go and if you do mythology +right and this is another one of the + + align:start position:0% +right and this is another one of the + + + align:start position:0% +right and this is another one of the +things that joseph campbell takes credit + + align:start position:0% +things that joseph campbell takes credit + + + align:start position:0% +things that joseph campbell takes credit +for that as a matter of fact this is + + align:start position:0% +for that as a matter of fact this is + + + align:start position:0% +for that as a matter of fact this is +really the + + align:start position:0% +really the + + + align:start position:0% +really the +the source of his fame that what he + + align:start position:0% +the source of his fame that what he + + + align:start position:0% +the source of his fame that what he +found out was + + align:start position:0% +found out was + + + align:start position:0% +found out was +that uh if you look at mythologies of + + align:start position:0% +that uh if you look at mythologies of + + + align:start position:0% +that uh if you look at mythologies of +all + + align:start position:0% +all + + + align:start position:0% +all +cultures you'll find a whole lot of + + align:start position:0% +cultures you'll find a whole lot of + + + align:start position:0% +cultures you'll find a whole lot of +things in common + + align:start position:0% +things in common + + + align:start position:0% +things in common +and the hero's journey is one of them + + align:start position:0% + + + + align:start position:0% + +and there are different kinds of + + align:start position:0% +and there are different kinds of + + + align:start position:0% +and there are different kinds of +heroes journeys and all of that but uh + + align:start position:0% +heroes journeys and all of that but uh + + + align:start position:0% +heroes journeys and all of that but uh +so therefore + + align:start position:0% +so therefore + + + align:start position:0% +so therefore +so + + align:start position:0% +so + + + align:start position:0% +so +your challenge then is to find somebody + + align:start position:0% +your challenge then is to find somebody + + + align:start position:0% +your challenge then is to find somebody +that you like i said that you know + + align:start position:0% +that you like i said that you know + + + align:start position:0% +that you like i said that you know +you don't have to know him personally + + align:start position:0% +you don't have to know him personally + + + align:start position:0% +you don't have to know him personally +they don't even have to be alive you can + + align:start position:0% +they don't even have to be alive you can + + + align:start position:0% +they don't even have to be alive you can +read them out of books i know that + + align:start position:0% +read them out of books i know that + + + align:start position:0% +read them out of books i know that +person + + align:start position:0% +person + + + align:start position:0% +person +but and say that uh-huh that person fits + + align:start position:0% +but and say that uh-huh that person fits + + + align:start position:0% +but and say that uh-huh that person fits +the pattern + + align:start position:0% +the pattern + + + align:start position:0% +the pattern +and if i really get in some trouble and + + align:start position:0% +and if i really get in some trouble and + + + align:start position:0% +and if i really get in some trouble and +do what i think that person will do it + + align:start position:0% +do what i think that person will do it + + + align:start position:0% +do what i think that person will do it +may not be the right thing + + align:start position:0% +may not be the right thing + + + align:start position:0% +may not be the right thing +but somehow or another i will still fit + + align:start position:0% +but somehow or another i will still fit + + + align:start position:0% +but somehow or another i will still fit +in the culture when it's done + + align:start position:0% + + + + align:start position:0% + +it will be probably the best you can do + + align:start position:0% +it will be probably the best you can do + + + align:start position:0% +it will be probably the best you can do +and um + + align:start position:0% +and um + + + align:start position:0% +and um +uh + + align:start position:0% + + + + align:start position:0% + +and and i was hoping the only reason i + + align:start position:0% +and and i was hoping the only reason i + + + align:start position:0% +and and i was hoping the only reason i +was hoping that this would be a bigger + + align:start position:0% +was hoping that this would be a bigger + + + align:start position:0% +was hoping that this would be a bigger +class + + align:start position:0% +class + + + align:start position:0% +class +the only reason + + align:start position:0% +the only reason + + + align:start position:0% +the only reason +is that i was hoping that we'd have a + + align:start position:0% +is that i was hoping that we'd have a + + + align:start position:0% +is that i was hoping that we'd have a +whole lot of people in here saying well + + align:start position:0% +whole lot of people in here saying well + + + align:start position:0% +whole lot of people in here saying well +you know where i'm from + + align:start position:0% +you know where i'm from + + + align:start position:0% +you know where i'm from +uh we got another story + + align:start position:0% +uh we got another story + + + align:start position:0% +uh we got another story +and the hero didn't go out and + + align:start position:0% +and the hero didn't go out and + + + align:start position:0% +and the hero didn't go out and +uh killed dragon + + align:start position:0% +uh killed dragon + + + align:start position:0% +uh killed dragon +the the hero went out and killed uh + + align:start position:0% +the the hero went out and killed uh + + + align:start position:0% +the the hero went out and killed uh +you know + + align:start position:0% +you know + + + align:start position:0% +you know +kill something else might be just as bad + + align:start position:0% +kill something else might be just as bad + + + align:start position:0% +kill something else might be just as bad +you know uh i've heard some stories from + + align:start position:0% +you know uh i've heard some stories from + + + align:start position:0% +you know uh i've heard some stories from +south americans where the person goes + + align:start position:0% +south americans where the person goes + + + align:start position:0% +south americans where the person goes +out and kills something in the forest + + align:start position:0% +out and kills something in the forest + + + align:start position:0% +out and kills something in the forest +well even + + align:start position:0% +well even + + + align:start position:0% +well even +even the even the anthropologists who + + align:start position:0% +even the even the anthropologists who + + + align:start position:0% +even the even the anthropologists who +study oedipus saying that + + align:start position:0% +study oedipus saying that + + + align:start position:0% +study oedipus saying that +he did not kill it was a sphinx that he + + align:start position:0% +he did not kill it was a sphinx that he + + + align:start position:0% +he did not kill it was a sphinx that he +killed + + align:start position:0% +killed + + + align:start position:0% +killed +um + + align:start position:0% +um + + + align:start position:0% +um +uh a line with a person's head that was + + align:start position:0% +uh a line with a person's head that was + + + align:start position:0% +uh a line with a person's head that was +terrorizing the terrorizing the populace + + align:start position:0% +terrorizing the terrorizing the populace + + + align:start position:0% +terrorizing the terrorizing the populace +what they what they did find something + + align:start position:0% +what they what they did find something + + + align:start position:0% +what they what they did find something +and i don't know how they did it but + + align:start position:0% +and i don't know how they did it but + + + align:start position:0% +and i don't know how they did it but +they found something they said around + + align:start position:0% +they found something they said around + + + align:start position:0% +they found something they said around +that place at around that time + + align:start position:0% +that place at around that time + + + align:start position:0% +that place at around that time +there was a there was a pesticide + + align:start position:0% +there was a there was a pesticide + + + align:start position:0% +there was a there was a pesticide +a disease + + align:start position:0% +a disease + + + align:start position:0% +a disease +and somehow another this man came in + + align:start position:0% +and somehow another this man came in + + + align:start position:0% +and somehow another this man came in +from outside and walked among the people + + align:start position:0% +from outside and walked among the people + + + align:start position:0% +from outside and walked among the people +and helped care + + align:start position:0% +and helped care + + + align:start position:0% +and helped care +well how does it work + + align:start position:0% +well how does it work + + + align:start position:0% +well how does it work +12 generations later when it gets down + + align:start position:0% +12 generations later when it gets down + + + align:start position:0% +12 generations later when it gets down +in the unconscious into a story + + align:start position:0% +in the unconscious into a story + + + align:start position:0% +in the unconscious into a story +kill dragon + + align:start position:0% + + + + align:start position:0% + +so now what i want you to do um + + align:start position:0% +so now what i want you to do um + + + align:start position:0% +so now what i want you to do um +since y'all got all of this free time + + align:start position:0% + + + + align:start position:0% + +is uh to take this last paper that i've + + align:start position:0% +is uh to take this last paper that i've + + + align:start position:0% +is uh to take this last paper that i've +given you + + align:start position:0% +given you + + + align:start position:0% +given you +back and resubmitted but + + align:start position:0% +back and resubmitted but + + + align:start position:0% +back and resubmitted but +you can change it if you want to + + align:start position:0% +you can change it if you want to + + + align:start position:0% +you can change it if you want to +these are good papers but + + align:start position:0% +these are good papers but + + + align:start position:0% +these are good papers but +what i want you to do is + + align:start position:0% + + + + align:start position:0% + +take the character that you analyze + + align:start position:0% +take the character that you analyze + + + align:start position:0% +take the character that you analyze +and substitute possible in there + + align:start position:0% + + + + align:start position:0% + +and if that doesn't work then substitute + + align:start position:0% +and if that doesn't work then substitute + + + align:start position:0% +and if that doesn't work then substitute +some kind of hero in there + + align:start position:0% +some kind of hero in there + + + align:start position:0% +some kind of hero in there +and see what that person would have done + + align:start position:0% +and see what that person would have done + + + align:start position:0% +and see what that person would have done +in that situation + + align:start position:0% +in that situation + + + align:start position:0% +in that situation +what would have been the consequences to + + align:start position:0% +what would have been the consequences to + + + align:start position:0% +what would have been the consequences to +that person + + align:start position:0% + + + + align:start position:0% + +what i would like for you to do is to + + align:start position:0% +what i would like for you to do is to + + + align:start position:0% +what i would like for you to do is to +try possible first + + align:start position:0% +try possible first + + + align:start position:0% +try possible first +if it does not work for you then choose + + align:start position:0% +if it does not work for you then choose + + + align:start position:0% +if it does not work for you then choose +another one + + align:start position:0% +another one + + + align:start position:0% +another one +but justify why that person is a mythic + + align:start position:0% +but justify why that person is a mythic + + + align:start position:0% +but justify why that person is a mythic +hero + + align:start position:0% +hero + + + align:start position:0% +hero +a mythic hero of some sort or another + + align:start position:0% +a mythic hero of some sort or another + + + align:start position:0% +a mythic hero of some sort or another +they have to like + + align:start position:0% + + + + align:start position:0% + +like my uncle roy and those they they + + align:start position:0% +like my uncle roy and those they they + + + align:start position:0% +like my uncle roy and those they they +had the they followed the pattern + + align:start position:0% +had the they followed the pattern + + + align:start position:0% +had the they followed the pattern +they heard the call they went out for a + + align:start position:0% +they heard the call they went out for a + + + align:start position:0% +they heard the call they went out for a +higher cause + + align:start position:0% +higher cause + + + align:start position:0% +higher cause +they had this fabulous experience + + align:start position:0% +they had this fabulous experience + + + align:start position:0% +they had this fabulous experience +they killed the dragon they brought the + + align:start position:0% +they killed the dragon they brought the + + + align:start position:0% +they killed the dragon they brought the +grail home and shared it with everybody + + align:start position:0% +grail home and shared it with everybody + + + align:start position:0% +grail home and shared it with everybody +there's the pattern + + align:start position:0% + + + + align:start position:0% + +so see if the if that if that doesn't + + align:start position:0% +so see if the if that if that doesn't + + + align:start position:0% +so see if the if that if that doesn't +work + + align:start position:0% +work + + + align:start position:0% +work +then pick another another case + + align:start position:0% +then pick another another case + + + align:start position:0% +then pick another another case +the a7d or some other case that you've + + align:start position:0% +the a7d or some other case that you've + + + align:start position:0% +the a7d or some other case that you've +already studied + + align:start position:0% + + + + align:start position:0% + +okay now i don't want to as we all know + + align:start position:0% +okay now i don't want to as we all know + + + align:start position:0% +okay now i don't want to as we all know +none of these methods will work + + align:start position:0% +none of these methods will work + + + align:start position:0% +none of these methods will work +every time on every + + align:start position:0% +every time on every + + + align:start position:0% +every time on every +everybody + + align:start position:0% +everybody + + + align:start position:0% +everybody +but uh so but i'd like for you to try + + align:start position:0% +but uh so but i'd like for you to try + + + align:start position:0% +but uh so but i'd like for you to try +possible honest on chernobyl \ No newline at end of file diff --git a/4r1xgrWbALg.txt b/4r1xgrWbALg.txt new file mode 100644 index 0000000000000000000000000000000000000000..41b276b2e1daeb1d06e99f1dd00ad9e3f4b814d2 --- /dev/null +++ b/4r1xgrWbALg.txt @@ -0,0 +1,475 @@ +align:start position:0% + +so I would like to now consider the + + align:start position:0% +so I would like to now consider the + + + align:start position:0% +so I would like to now consider the +wheel that is rolling without slipping + + align:start position:0% +wheel that is rolling without slipping + + + align:start position:0% +wheel that is rolling without slipping +and what I'd like to do is + + align:start position:0% +and what I'd like to do is + + + align:start position:0% +and what I'd like to do is +consider let's draw the wheel rolling + + align:start position:0% +consider let's draw the wheel rolling + + + align:start position:0% +consider let's draw the wheel rolling +without slipping and I'd like to + + align:start position:0% +without slipping and I'd like to + + + align:start position:0% +without slipping and I'd like to +consider the contact + + align:start position:0% + + + + align:start position:0% + +point between the + + align:start position:0% +point between the + + + align:start position:0% +point between the +wheel and the + + align:start position:0% +wheel and the + + + align:start position:0% +wheel and the +ground and I'd like to understand what + + align:start position:0% +ground and I'd like to understand what + + + align:start position:0% +ground and I'd like to understand what +the velocity of that contact point is + + align:start position:0% +the velocity of that contact point is + + + align:start position:0% +the velocity of that contact point is +and the result is surprising now we know + + align:start position:0% +and the result is surprising now we know + + + align:start position:0% +and the result is surprising now we know +by our law of additional velocities + + align:start position:0% +by our law of additional velocities + + + align:start position:0% +by our law of additional velocities +let's call that the point P that the + + align:start position:0% +let's call that the point P that the + + + align:start position:0% +let's call that the point P that the +velocity of p is the velocity of the + + align:start position:0% +velocity of p is the velocity of the + + + align:start position:0% +velocity of p is the velocity of the +center of mass and that pointed this way + + align:start position:0% +center of mass and that pointed this way + + + align:start position:0% +center of mass and that pointed this way +plus the velocity of the point p as seen + + align:start position:0% +plus the velocity of the point p as seen + + + align:start position:0% +plus the velocity of the point p as seen +in the center of Mass frame and in that + + align:start position:0% +in the center of Mass frame and in that + + + align:start position:0% +in the center of Mass frame and in that +frame every single point on the rim was + + align:start position:0% +frame every single point on the rim was + + + align:start position:0% +frame every single point on the rim was +just doing circular motion so that + + align:start position:0% +just doing circular motion so that + + + align:start position:0% +just doing circular motion so that +velocity + + align:start position:0% +velocity + + + align:start position:0% +velocity +is in the opposite direction and the + + align:start position:0% +is in the opposite direction and the + + + align:start position:0% +is in the opposite direction and the +vector sum is the velocity of this point + + align:start position:0% +vector sum is the velocity of this point + + + align:start position:0% +vector sum is the velocity of this point +p as seen in the ground + + align:start position:0% +p as seen in the ground + + + align:start position:0% +p as seen in the ground +frame so we want to consider the + + align:start position:0% +frame so we want to consider the + + + align:start position:0% +frame so we want to consider the +magnitudes of these two terms the + + align:start position:0% +magnitudes of these two terms the + + + align:start position:0% +magnitudes of these two terms the +Velocity in the center of Mass frame of + + align:start position:0% +Velocity in the center of Mass frame of + + + align:start position:0% +Velocity in the center of Mass frame of +a point in the rim has a magnitude equal + + align:start position:0% +a point in the rim has a magnitude equal + + + align:start position:0% +a point in the rim has a magnitude equal +to our + + align:start position:0% +to our + + + align:start position:0% +to our +Omega and we said that the + + align:start position:0% +Omega and we said that the + + + align:start position:0% +Omega and we said that the +velocity of this a center of mass we + + align:start position:0% +velocity of this a center of mass we + + + align:start position:0% +velocity of this a center of mass we +call that V CM now the + + align:start position:0% +call that V CM now the + + + align:start position:0% +call that V CM now the +rolling without spping condition was + + align:start position:0% +rolling without spping condition was + + + align:start position:0% +rolling without spping condition was +that these two magnitudes were equal vcm + + align:start position:0% +that these two magnitudes were equal vcm + + + align:start position:0% +that these two magnitudes were equal vcm +equals R Omega or the velocity of the + + align:start position:0% +equals R Omega or the velocity of the + + + align:start position:0% +equals R Omega or the velocity of the +point on the rim in the center of Mass + + align:start position:0% +point on the rim in the center of Mass + + + align:start position:0% +point on the rim in the center of Mass +frame is equal to the center Mass + + align:start position:0% +frame is equal to the center Mass + + + align:start position:0% +frame is equal to the center Mass +velocity of the wheel and therefore the + + align:start position:0% +velocity of the wheel and therefore the + + + align:start position:0% +velocity of the wheel and therefore the +velocity P which is the sum of these two + + align:start position:0% +velocity P which is the sum of these two + + + align:start position:0% +velocity P which is the sum of these two +vectors for the contact + + align:start position:0% +vectors for the contact + + + align:start position:0% +vectors for the contact +point so that's when p + + align:start position:0% +point so that's when p + + + align:start position:0% +point so that's when p +is in contact with the ground is equal + + align:start position:0% +is in contact with the ground is equal + + + align:start position:0% +is in contact with the ground is equal +to zero so what we say is that the + + align:start position:0% +to zero so what we say is that the + + + align:start position:0% +to zero so what we say is that the +contact + + align:start position:0% + + + + align:start position:0% + +point is + + align:start position:0% + + + + align:start position:0% + +instantaneously at + + align:start position:0% +instantaneously at + + + align:start position:0% +instantaneously at +rest + + align:start position:0% +rest + + + align:start position:0% +rest +with + + align:start position:0% +with + + + align:start position:0% +with +respect to the + + align:start position:0% + + + + align:start position:0% + +ground and that's what really is the + + align:start position:0% +ground and that's what really is the + + + align:start position:0% +ground and that's what really is the +mystery of a wheel that's rolling + + align:start position:0% +mystery of a wheel that's rolling + + + align:start position:0% +mystery of a wheel that's rolling +without slipping that this contact point + + align:start position:0% +without slipping that this contact point + + + align:start position:0% +without slipping that this contact point +is the sum of these two vectors and it's + + align:start position:0% +is the sum of these two vectors and it's + + + align:start position:0% +is the sum of these two vectors and it's +instantaneously at rest with the ground + + align:start position:0% +instantaneously at rest with the ground + + + align:start position:0% +instantaneously at rest with the ground +when the Reel is rolling without + + align:start position:0% +when the Reel is rolling without + + + align:start position:0% +when the Reel is rolling without +slipping the other points are certainly + + align:start position:0% +slipping the other points are certainly + + + align:start position:0% +slipping the other points are certainly +not remember up here these two vectors + + align:start position:0% +not remember up here these two vectors + + + align:start position:0% +not remember up here these two vectors +pointed in the same + + align:start position:0% +pointed in the same + + + align:start position:0% +pointed in the same +direction so that that Vector has twice + + align:start position:0% +direction so that that Vector has twice + + + align:start position:0% +direction so that that Vector has twice +the magnitude of either + + align:start position:0% + + + + align:start position:0% + +one \ No newline at end of file diff --git a/5RqTJWf1l_A.txt b/5RqTJWf1l_A.txt new file mode 100644 index 0000000000000000000000000000000000000000..85cea9d6ab71ddf48438e37d2fabaf64800f88a2 --- /dev/null +++ b/5RqTJWf1l_A.txt @@ -0,0 +1,4491 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +to view additional materials from + + align:start position:0% +to view additional materials from + + + align:start position:0% +to view additional materials from +hundreds of MIT courses visit MIT open + + align:start position:0% +hundreds of MIT courses visit MIT open + + + align:start position:0% +hundreds of MIT courses visit MIT open +courseware at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu all right all right so we're + + align:start position:0% +ocw.mit.edu all right all right so we're + + + align:start position:0% +ocw.mit.edu all right all right so we're +going to continue now and kind of get + + align:start position:0% +going to continue now and kind of get + + + align:start position:0% +going to continue now and kind of get +into the examples part of the uh of the + + align:start position:0% +into the examples part of the uh of the + + + align:start position:0% +into the examples part of the uh of the +course and again this is really the part + + align:start position:0% +course and again this is really the part + + + align:start position:0% +course and again this is really the part +that uh people should really I I I + + align:start position:0% +that uh people should really I I I + + + align:start position:0% +that uh people should really I I I +strongly encourage people doing the + + align:start position:0% +strongly encourage people doing the + + + align:start position:0% +strongly encourage people doing the +examples how many people got a chance to + + align:start position:0% +examples how many people got a chance to + + + align:start position:0% +examples how many people got a chance to +try the examples in the very good and we + + align:start position:0% +try the examples in the very good and we + + + align:start position:0% +try the examples in the very good and we +got a couple of questions for people and + + align:start position:0% +got a couple of questions for people and + + + align:start position:0% +got a couple of questions for people and +and most of the time we got another + + align:start position:0% +and most of the time we got another + + + align:start position:0% +and most of the time we got another +email from them right away that said + + align:start position:0% +email from them right away that said + + + align:start position:0% +email from them right away that said +oops no got it to work so we're very + + align:start position:0% +oops no got it to work so we're very + + + align:start position:0% +oops no got it to work so we're very +pleased about that uh very you know the + + align:start position:0% +pleased about that uh very you know the + + + align:start position:0% +pleased about that uh very you know the +great thing about working at Lincoln + + align:start position:0% +great thing about working at Lincoln + + + align:start position:0% +great thing about working at Lincoln +Labs is people are pretty good at figur + + align:start position:0% +Labs is people are pretty good at figur + + + align:start position:0% +Labs is people are pretty good at figur +ing stuff out + + align:start position:0% + + + + align:start position:0% + +um we have some experiened this and + + align:start position:0% +um we have some experiened this and + + + align:start position:0% +um we have some experiened this and +before obviously our parallel matlb + + align:start position:0% +before obviously our parallel matlb + + + align:start position:0% +before obviously our parallel matlb +technology we've released that out many + + align:start position:0% +technology we've released that out many + + + align:start position:0% +technology we've released that out many +many people use it and for the most part + + align:start position:0% +many people use it and for the most part + + + align:start position:0% +many people use it and for the most part +we're proud to say that whenever we get + + align:start position:0% +we're proud to say that whenever we get + + + align:start position:0% +we're proud to say that whenever we get +a a question from the outside world and + + align:start position:0% +a a question from the outside world and + + + align:start position:0% +a a question from the outside world and +it's not working it's it's usually the + + align:start position:0% +it's not working it's it's usually the + + + align:start position:0% +it's not working it's it's usually the +person has taken severely active steps + + align:start position:0% +person has taken severely active steps + + + align:start position:0% +person has taken severely active steps +to ignore the + + align:start position:0% +to ignore the + + + align:start position:0% +to ignore the +documentation you know and uh and uh and + + align:start position:0% +documentation you know and uh and uh and + + + align:start position:0% +documentation you know and uh and uh and +but if they they follow it at all + + align:start position:0% +but if they they follow it at all + + + align:start position:0% +but if they they follow it at all +they're generally pretty pretty safe + + align:start position:0% +they're generally pretty pretty safe + + + align:start position:0% +they're generally pretty pretty safe +so I'm going to get into the example + + align:start position:0% +so I'm going to get into the example + + + align:start position:0% +so I'm going to get into the example +code here so the example code this is oh + + align:start position:0% +code here so the example code this is oh + + + align:start position:0% +code here so the example code this is oh +that's not d4m user share that's + + align:start position:0% +that's not d4m user share that's + + + align:start position:0% +that's not d4m user share that's +incorrect it's tools lowercase examples + + align:start position:0% +incorrect it's tools lowercase examples + + + align:start position:0% +incorrect it's tools lowercase examples +I should correct these + + align:start position:0% + + + + align:start position:0% + +slides + + align:start position:0% + + + + align:start position:0% + +oh nice there we + + align:start position:0% +oh nice there we + + + align:start position:0% +oh nice there we +go + + align:start position:0% +go + + + align:start position:0% +go +great it is an X + + align:start position:0% + + + + align:start position:0% + +right oh yes thank + + align:start position:0% + + + + align:start position:0% + +you + + align:start position:0% + + + + align:start position:0% + +great all right so this is where the + + align:start position:0% +great all right so this is where the + + + align:start position:0% +great all right so this is where the +example code is uh but we're going to go + + align:start position:0% +example code is uh but we're going to go + + + align:start position:0% +example code is uh but we're going to go +over here um your assignment should you + + align:start position:0% +over here um your assignment should you + + + align:start position:0% +over here um your assignment should you +choose to undertake it um is to + + align:start position:0% +choose to undertake it um is to + + + align:start position:0% +choose to undertake it um is to +um pick a + + align:start position:0% +um pick a + + + align:start position:0% +um pick a +picture hopefully someone that's + + align:start position:0% +picture hopefully someone that's + + + align:start position:0% +picture hopefully someone that's +interesting to you doesn't have to be + + align:start position:0% +interesting to you doesn't have to be + + + align:start position:0% +interesting to you doesn't have to be +straight lines it could be anything + + align:start position:0% +straight lines it could be anything + + + align:start position:0% +straight lines it could be anything +where you could create draw edges or + + align:start position:0% +where you could create draw edges or + + + align:start position:0% +where you could create draw edges or +something you take some photo and put it + + align:start position:0% +something you take some photo and put it + + + align:start position:0% +something you take some photo and put it +through one of those photosho effects + + align:start position:0% +through one of those photosho effects + + + align:start position:0% +through one of those photosho effects +and turn it into a line drawing or + + align:start position:0% +and turn it into a line drawing or + + + align:start position:0% +and turn it into a line drawing or +something and then start labeling + + align:start position:0% +something and then start labeling + + + align:start position:0% +something and then start labeling +vertices + + align:start position:0% +vertices + + + align:start position:0% +vertices +um you do want to limit the number of + + align:start position:0% +um you do want to limit the number of + + + align:start position:0% +um you do want to limit the number of +lines though I would recommend 20 would + + align:start position:0% +lines though I would recommend 20 would + + + align:start position:0% +lines though I would recommend 20 would +be the most number of lines you do + + align:start position:0% +be the most number of lines you do + + + align:start position:0% +be the most number of lines you do +because this can get fairly involved you + + align:start position:0% +because this can get fairly involved you + + + align:start position:0% +because this can get fairly involved you +might start with something fairly small + + align:start position:0% +might start with something fairly small + + + align:start position:0% +might start with something fairly small +so select a picture label the edges and + + align:start position:0% +so select a picture label the edges and + + + align:start position:0% +so select a picture label the edges and +vertices create an incidence + + align:start position:0% +vertices create an incidence + + + align:start position:0% +vertices create an incidence +Matrix okay and then just compute The + + align:start position:0% +Matrix okay and then just compute The + + + align:start position:0% +Matrix okay and then just compute The +adjacency Matrix from the incidence + + align:start position:0% +adjacency Matrix from the incidence + + + align:start position:0% +adjacency Matrix from the incidence +Matrix using this this formula you can + + align:start position:0% +Matrix using this this formula you can + + + align:start position:0% +Matrix using this this formula you can +certainly use d4m if you want to do that + + align:start position:0% +certainly use d4m if you want to do that + + + align:start position:0% +certainly use d4m if you want to do that +but it's fine to do it by hand it's fine + + align:start position:0% +but it's fine to do it by hand it's fine + + + align:start position:0% +but it's fine to do it by hand it's fine +to do it by hand just in which case you + + align:start position:0% +to do it by hand just in which case you + + + align:start position:0% +to do it by hand just in which case you +would want to do a very small one just + + align:start position:0% +would want to do a very small one just + + + align:start position:0% +would want to do a very small one just +you know do doing it once by hand is is + + align:start position:0% +you know do doing it once by hand is is + + + align:start position:0% +you know do doing it once by hand is is +useful you know twice marginally and + + align:start position:0% +useful you know twice marginally and + + + align:start position:0% +useful you know twice marginally and +then the third time not not useful but + + align:start position:0% +then the third time not not useful but + + + align:start position:0% +then the third time not not useful but +just like in high school right they make + + align:start position:0% +just like in high school right they make + + + align:start position:0% +just like in high school right they make +you do Matrix multiply by hand + + align:start position:0% +you do Matrix multiply by hand + + + align:start position:0% +you do Matrix multiply by hand +like actually a lot you know a lot + + align:start position:0% +like actually a lot you know a lot + + + align:start position:0% +like actually a lot you know a lot +so so uh so that's the example and the + + align:start position:0% +so so uh so that's the example and the + + + align:start position:0% +so so uh so that's the example and the +assignment + + align:start position:0% +assignment + + + align:start position:0% +assignment +um if + + align:start position:0% +um if + + + align:start position:0% +um if +you do this on a piece of paper and scan + + align:start position:0% +you do this on a piece of paper and scan + + + align:start position:0% +you do this on a piece of paper and scan +it and email it to me before the next + + align:start position:0% +it and email it to me before the next + + + align:start position:0% +it and email it to me before the next +lecture I will get you give you some + + align:start position:0% +lecture I will get you give you some + + + align:start position:0% +lecture I will get you give you some +feedback on it before the following + + align:start position:0% +feedback on it before the following + + + align:start position:0% +feedback on it before the following +lecture so you know you say to get give + + align:start position:0% +lecture so you know you say to get give + + + align:start position:0% +lecture so you know you say to get give +it to me after + + align:start position:0% +it to me after + + + align:start position:0% +it to me after +that too bad right no I just won't give + + align:start position:0% +that too bad right no I just won't give + + + align:start position:0% +that too bad right no I just won't give +you feedback you know so there's no + + align:start position:0% +you feedback you know so there's no + + + align:start position:0% +you feedback you know so there's no +credit but you know this gives you some + + align:start position:0% +credit but you know this gives you some + + + align:start position:0% +credit but you know this gives you some +incentive to get it done if you want + + align:start position:0% +incentive to get it done if you want + + + align:start position:0% +incentive to get it done if you want +feedback from me about you know what + + align:start position:0% +feedback from me about you know what + + + align:start position:0% +feedback from me about you know what +what what you did make sense or if you + + align:start position:0% +what what you did make sense or if you + + + align:start position:0% +what what you did make sense or if you +encountered like I picked this picture + + align:start position:0% +encountered like I picked this picture + + + align:start position:0% +encountered like I picked this picture +and now I don't understand you know I + + align:start position:0% +and now I don't understand you know I + + + align:start position:0% +and now I don't understand you know I +did my best but I have questions about + + align:start position:0% +did my best but I have questions about + + + align:start position:0% +did my best but I have questions about +how I did this you know doesn't make + + align:start position:0% +how I did this you know doesn't make + + + align:start position:0% +how I did this you know doesn't make +sense I'd be happy to do that so just + + align:start position:0% +sense I'd be happy to do that so just + + + align:start position:0% +sense I'd be happy to do that so just +scan it email it to me or if it is + + align:start position:0% +scan it email it to me or if it is + + + align:start position:0% +scan it email it to me or if it is +electronic format you know you can do + + align:start position:0% +electronic format you know you can do + + + align:start position:0% +electronic format you know you can do +that as well so the lecture portion and + + align:start position:0% +that as well so the lecture portion and + + + align:start position:0% +that as well so the lecture portion and +now go back + + align:start position:0% +now go back + + + align:start position:0% +now go back +here + + align:start position:0% +here + + + align:start position:0% +here +and let's see here we go to + + align:start position:0% +and let's see here we go to + + + align:start position:0% +and let's see here we go to +examples all right so we're in the + + align:start position:0% +examples all right so we're in the + + + align:start position:0% +examples all right so we're in the +intro the Edge Art + + align:start position:0% +intro the Edge Art + + + align:start position:0% +intro the Edge Art +directory start my at lab shell + + align:start position:0% + + + + align:start position:0% + +right + + align:start position:0% + + + + align:start position:0% + +place takes about 15 seconds for it to + + align:start position:0% +place takes about 15 seconds for it to + + + align:start position:0% +place takes about 15 seconds for it to +do + + align:start position:0% + + + + align:start position:0% + +this uh this particular thing always CDs + + align:start position:0% +this uh this particular thing always CDs + + + align:start position:0% +this uh this particular thing always CDs +me to the the location of the directory + + align:start position:0% +me to the the location of the directory + + + align:start position:0% +me to the the location of the directory +you need to do that in order to see the + + align:start position:0% +you need to do that in order to see the + + + align:start position:0% +you need to do that in order to see the +examples um I think most mat lab users + + align:start position:0% +examples um I think most mat lab users + + + align:start position:0% +examples um I think most mat lab users +are familiar with that but just some + + align:start position:0% +are familiar with that but just some + + + align:start position:0% +are familiar with that but just some +that some that are + + align:start position:0% + + + + align:start position:0% + +not hide that here is the actual + + align:start position:0% +not hide that here is the actual + + + align:start position:0% +not hide that here is the actual +adjacency + + align:start position:0% +adjacency + + + align:start position:0% +adjacency +Matrix of that + + align:start position:0% +Matrix of that + + + align:start position:0% +Matrix of that +painting so there it is same thing we + + align:start position:0% +painting so there it is same thing we + + + align:start position:0% +painting so there it is same thing we +just saw so this is the data set that + + align:start position:0% +just saw so this is the data set that + + + align:start position:0% +just saw so this is the data set that +we're going to work with + + align:start position:0% + + + + align:start position:0% + +here all right so I'm going to do ea1 + + align:start position:0% +here all right so I'm going to do ea1 + + + align:start position:0% +here all right so I'm going to do ea1 +again the numbered one you know the + + align:start position:0% +again the numbered one you know the + + + align:start position:0% +again the numbered one you know the +courses all the examples are numbered in + + align:start position:0% +courses all the examples are numbered in + + + align:start position:0% +courses all the examples are numbered in +order kind of that you're supposed to + + align:start position:0% +order kind of that you're supposed to + + + align:start position:0% +order kind of that you're supposed to +proceed through them and if you see kind + + align:start position:0% +proceed through them and if you see kind + + + align:start position:0% +proceed through them and if you see kind +of a file in a directory that's like + + align:start position:0% +of a file in a directory that's like + + + align:start position:0% +of a file in a directory that's like +Capital couple Capital levers which are + + align:start position:0% +Capital couple Capital levers which are + + + align:start position:0% +Capital couple Capital levers which are +the first two letters of the the + + align:start position:0% +the first two letters of the the + + + align:start position:0% +the first two letters of the the +directory or the abbreviation of the + + align:start position:0% +directory or the abbreviation of the + + + align:start position:0% +directory or the abbreviation of the +directory and a test that is the + + align:start position:0% +directory and a test that is the + + + align:start position:0% +directory and a test that is the +examples the other files are just + + align:start position:0% +examples the other files are just + + + align:start position:0% +examples the other files are just +supporting files you don't aren't + + align:start position:0% +supporting files you don't aren't + + + align:start position:0% +supporting files you don't aren't +expected to run + + align:start position:0% +expected to run + + + align:start position:0% +expected to run +those try running them but they'll + + align:start position:0% +those try running them but they'll + + + align:start position:0% +those try running them but they'll +probably C you problems if you run them + + align:start position:0% +probably C you problems if you run them + + + align:start position:0% +probably C you problems if you run them +by + + align:start position:0% +by + + + align:start position:0% +by +themselves all right here we go so we + + align:start position:0% +themselves all right here we go so we + + + align:start position:0% +themselves all right here we go so we +just ran that + + align:start position:0% +just ran that + + + align:start position:0% +just ran that +example let's see what we + + align:start position:0% +example let's see what we + + + align:start position:0% +example let's see what we +got and let me + + align:start position:0% +got and let me + + + align:start position:0% +got and let me +uh this a little bit + + align:start position:0% +uh this a little bit + + + align:start position:0% +uh this a little bit +smaller + + align:start position:0% + + + + align:start position:0% + +bigger + + align:start position:0% +bigger + + + align:start position:0% +bigger +all right I think that worked all right + + align:start position:0% +all right I think that worked all right + + + align:start position:0% +all right I think that worked all right +so first thing we did here is we read in + + align:start position:0% +so first thing we did here is we read in + + + align:start position:0% +so first thing we did here is we read in +our data so we have this read CSV very + + align:start position:0% +our data so we have this read CSV very + + + align:start position:0% +our data so we have this read CSV very +useful + + align:start position:0% +useful + + + align:start position:0% +useful +function + + align:start position:0% +function + + + align:start position:0% +function +um not necessarily the fastest in some + + align:start position:0% +um not necessarily the fastest in some + + + align:start position:0% +um not necessarily the fastest in some +of the later + + align:start position:0% +of the later + + + align:start position:0% +of the later +examples uh we have a sort of a super + + align:start position:0% +examples uh we have a sort of a super + + + align:start position:0% +examples uh we have a sort of a super +fast reader which does almost no + + align:start position:0% +fast reader which does almost no + + + align:start position:0% +fast reader which does almost no +formatting for you so of just reads in + + align:start position:0% +formatting for you so of just reads in + + + align:start position:0% +formatting for you so of just reads in +the triples as raw triples because a lot + + align:start position:0% +the triples as raw triples because a lot + + + align:start position:0% +the triples as raw triples because a lot +of times if you're reading a very large + + align:start position:0% +of times if you're reading a very large + + + align:start position:0% +of times if you're reading a very large +CSV + + align:start position:0% +CSV + + + align:start position:0% +CSV +file you may not want to construct the + + align:start position:0% +file you may not want to construct the + + + align:start position:0% +file you may not want to construct the +full associative array out of the way we + + align:start position:0% +full associative array out of the way we + + + align:start position:0% +full associative array out of the way we +would just sort of do it by default and + + align:start position:0% +would just sort of do it by default and + + + align:start position:0% +would just sort of do it by default and +you can just read in the triples very + + align:start position:0% +you can just read in the triples very + + + align:start position:0% +you can just read in the triples very +quickly and then do some manipulations + + align:start position:0% +quickly and then do some manipulations + + + align:start position:0% +quickly and then do some manipulations +or a lot of times the first thing you'll + + align:start position:0% +or a lot of times the first thing you'll + + + align:start position:0% +or a lot of times the first thing you'll +do is recreate an associative array and + + align:start position:0% +do is recreate an associative array and + + + align:start position:0% +do is recreate an associative array and +then get the triples out of it because + + align:start position:0% +then get the triples out of it because + + + align:start position:0% +then get the triples out of it because +you want to work on the triples directly + + align:start position:0% +you want to work on the triples directly + + + align:start position:0% +you want to work on the triples directly +and so so we do have ways for doing that + + align:start position:0% +and so so we do have ways for doing that + + + align:start position:0% +and so so we do have ways for doing that +so this is the uh we now created the + + align:start position:0% +so this is the uh we now created the + + + align:start position:0% +so this is the uh we now created the +incidence Matrix into an associative + + align:start position:0% +incidence Matrix into an associative + + + align:start position:0% +incidence Matrix into an associative +array + + align:start position:0% + + + + align:start position:0% + +and let me go down here let me just show + + align:start position:0% +and let me go down here let me just show + + + align:start position:0% +and let me go down here let me just show +you that so if I go + + align:start position:0% +you that so if I go + + + align:start position:0% +you that so if I go +disp so that shows you the incidence + + align:start position:0% +disp so that shows you the incidence + + + align:start position:0% +disp so that shows you the incidence +Matrix these are its internal structures + + align:start position:0% +Matrix these are its internal structures + + + align:start position:0% +Matrix these are its internal structures +here these are the row keys so those are + + align:start position:0% +here these are the row keys so those are + + + align:start position:0% +here these are the row keys so those are +the recall the uh the labels of the + + align:start position:0% +the recall the uh the labels of the + + + align:start position:0% +the recall the uh the labels of the +edges they have been converted to lexor + + align:start position:0% +edges they have been converted to lexor + + + align:start position:0% +edges they have been converted to lexor +graphically sorted + + align:start position:0% +graphically sorted + + + align:start position:0% +graphically sorted +order we have the column keys but + + align:start position:0% +order we have the column keys but + + + align:start position:0% +order we have the column keys but +there's so many that that mat lab + + align:start position:0% +there's so many that that mat lab + + + align:start position:0% +there's so many that that mat lab +chooses not to print out the full list + + align:start position:0% +chooses not to print out the full list + + + align:start position:0% +chooses not to print out the full list +here but it's again a lexographic sorted + + align:start position:0% +here but it's again a lexographic sorted + + + align:start position:0% +here but it's again a lexographic sorted +list of the unique column labels these + + align:start position:0% +list of the unique column labels these + + + align:start position:0% +list of the unique column labels these +are the different values that we + + align:start position:0% +are the different values that we + + + align:start position:0% +are the different values that we +have so this is you remember we had an + + align:start position:0% +have so this is you remember we had an + + + align:start position:0% +have so this is you remember we had an +order column which is one two three blue + + align:start position:0% +order column which is one two three blue + + + align:start position:0% +order column which is one two three blue +green orange pink silver + + align:start position:0% +green orange pink silver + + + align:start position:0% +green orange pink silver +Etc and here uh you know and then the + + align:start position:0% +Etc and here uh you know and then the + + + align:start position:0% +Etc and here uh you know and then the +overall adjacency Matrix which connects + + align:start position:0% +overall adjacency Matrix which connects + + + align:start position:0% +overall adjacency Matrix which connects +the row keys to their value keys + + align:start position:0% +the row keys to their value keys + + + align:start position:0% +the row keys to their value keys +is 19 by + + align:start position:0% +is 19 by + + + align:start position:0% +is 19 by +21 19 19 rows by 21 columns this + + align:start position:0% +21 19 19 rows by 21 columns this + + + align:start position:0% +21 19 19 rows by 21 columns this +actually shows a mixed use right some of + + align:start position:0% +actually shows a mixed use right some of + + + align:start position:0% +actually shows a mixed use right some of +these are essentially exploded right the + + align:start position:0% +these are essentially exploded right the + + + align:start position:0% +these are essentially exploded right the +fact that we have each each Edge but + + align:start position:0% +fact that we have each each Edge but + + + align:start position:0% +fact that we have each each Edge but +some of the values are actually storing + + align:start position:0% +some of the values are actually storing + + + align:start position:0% +some of the values are actually storing +real stuff here blue green orange Etc so + + align:start position:0% +real stuff here blue green orange Etc so + + + align:start position:0% +real stuff here blue green orange Etc so +you don't have to go all the way with + + align:start position:0% +you don't have to go all the way with + + + align:start position:0% +you don't have to go all the way with +one you can mix them to around you can + + align:start position:0% +one you can mix them to around you can + + + align:start position:0% +one you can mix them to around you can +create dense matrices that look more + + align:start position:0% +create dense matrices that look more + + + align:start position:0% +create dense matrices that look more +like traditional tables and there's + + align:start position:0% +like traditional tables and there's + + + align:start position:0% +like traditional tables and there's +sometimes that you want to do that and + + align:start position:0% +sometimes that you want to do that and + + + align:start position:0% +sometimes that you want to do that and +other times you can sort of completely + + align:start position:0% +other times you can sort of completely + + + align:start position:0% +other times you can sort of completely +explode it out and do things like that + + align:start position:0% +explode it out and do things like that + + + align:start position:0% +explode it out and do things like that +as well + + align:start position:0% + + + + align:start position:0% + +so so we go + + align:start position:0% +so so we go + + + align:start position:0% +so so we go +back um we just want to work with the + + align:start position:0% +back um we just want to work with the + + + align:start position:0% +back um we just want to work with the +vertices okay so we're going to ignore + + align:start position:0% +vertices okay so we're going to ignore + + + align:start position:0% +vertices okay so we're going to ignore +this color and Order column so we're + + align:start position:0% +this color and Order column so we're + + + align:start position:0% +this color and Order column so we're +going to create our first projection is + + align:start position:0% +going to create our first projection is + + + align:start position:0% +going to create our first projection is +to just work with the vertices so we + + align:start position:0% +to just work with the vertices so we + + + align:start position:0% +to just work with the vertices so we +have this little short hand here called + + align:start position:0% +have this little short hand here called + + + align:start position:0% +have this little short hand here called +starts with if you give it a a character + + align:start position:0% +starts with if you give it a a character + + + align:start position:0% +starts with if you give it a a character +and it will create a little query + + align:start position:0% +and it will create a little query + + + align:start position:0% +and it will create a little query +that'll that will get just things that + + align:start position:0% +that'll that will get just things that + + + align:start position:0% +that'll that will get just things that +start with that and very useful thing is + + align:start position:0% +start with that and very useful thing is + + + align:start position:0% +start with that and very useful thing is +very efficient too it actually formally + + align:start position:0% +very efficient too it actually formally + + + align:start position:0% +very efficient too it actually formally +creates the two bounding it figures out + + align:start position:0% +creates the two bounding it figures out + + + align:start position:0% +creates the two bounding it figures out +what the maximum range is for that and + + align:start position:0% +what the maximum range is for that and + + + align:start position:0% +what the maximum range is for that and +then it just needs to look up you know + + align:start position:0% +then it just needs to look up you know + + + align:start position:0% +then it just needs to look up you know +the beginning and the end it can assume + + align:start position:0% +the beginning and the end it can assume + + + align:start position:0% +the beginning and the end it can assume +lexor graphical order and then it can + + align:start position:0% +lexor graphical order and then it can + + + align:start position:0% +lexor graphical order and then it can +just grab the middle so much we have a + + align:start position:0% +just grab the middle so much we have a + + + align:start position:0% +just grab the middle so much we have a +regular expression approach too which + + align:start position:0% +regular expression approach too which + + + align:start position:0% +regular expression approach too which +works fine on small associative arrays + + align:start position:0% +works fine on small associative arrays + + + align:start position:0% +works fine on small associative arrays +but this is much more efficient because + + align:start position:0% +but this is much more efficient because + + + align:start position:0% +but this is much more efficient because +it's just basically two lookups and go + + align:start position:0% +it's just basically two lookups and go + + + align:start position:0% +it's just basically two lookups and go +um it also works if this e was actually + + align:start position:0% +um it also works if this e was actually + + + align:start position:0% +um it also works if this e was actually +a binding to a table in a database you + + align:start position:0% +a binding to a table in a database you + + + align:start position:0% +a binding to a table in a database you +can use the same syntax while the + + align:start position:0% +can use the same syntax while the + + + align:start position:0% +can use the same syntax while the +regular expression syntax doesn't really + + align:start position:0% +regular expression syntax doesn't really + + + align:start position:0% +regular expression syntax doesn't really +work + + align:start position:0% + + + + align:start position:0% + +yes so that's the delimiter of the + + align:start position:0% +yes so that's the delimiter of the + + + align:start position:0% +yes so that's the delimiter of the +string so it's a string list with one + + align:start position:0% +string so it's a string list with one + + + align:start position:0% +string so it's a string list with one +entry in it so this is a string list all + + align:start position:0% +entry in it so this is a string list all + + + align:start position:0% +entry in it so this is a string list all +our strings list here well because this + + align:start position:0% +our strings list here well because this + + + align:start position:0% +our strings list here well because this +also allows me could have been anything + + align:start position:0% +also allows me could have been anything + + + align:start position:0% +also allows me could have been anything +that was that was unique to that okay + + align:start position:0% +that was that was unique to that okay + + + align:start position:0% +that was that was unique to that okay +and didn't have to be the same delimiter + + align:start position:0% +and didn't have to be the same delimiter + + + align:start position:0% +and didn't have to be the same delimiter +that was the one inside could have been + + align:start position:0% +that was the one inside could have been + + + align:start position:0% +that was the one inside could have been +a new line could have been a tab could + + align:start position:0% +a new line could have been a tab could + + + align:start position:0% +a new line could have been a tab could +whatever I just picked comma because it + + align:start position:0% +whatever I just picked comma because it + + + align:start position:0% +whatever I just picked comma because it +was convenient but could have been a + + align:start position:0% +was convenient but could have been a + + + align:start position:0% +was convenient but could have been a +space um because you can have multiple + + align:start position:0% +space um because you can have multiple + + + align:start position:0% +space um because you can have multiple +arguments to the starts with if you want + + align:start position:0% +arguments to the starts with if you want + + + align:start position:0% +arguments to the starts with if you want +to say I want starts with this and + + align:start position:0% +to say I want starts with this and + + + align:start position:0% +to say I want starts with this and +starts with this and starts with this + + align:start position:0% +starts with this and starts with this + + + align:start position:0% +starts with this and starts with this +you just give it a whole list and we'll + + align:start position:0% +you just give it a whole list and we'll + + + align:start position:0% +you just give it a whole list and we'll +go and do that all for you um and so + + align:start position:0% +go and do that all for you um and so + + + align:start position:0% +go and do that all for you um and so +that's why we do it that way wherever + + align:start position:0% +that's why we do it that way wherever + + + align:start position:0% +that's why we do it that way wherever +possible we try and accept a list of + + align:start position:0% +possible we try and accept a list of + + + align:start position:0% +possible we try and accept a list of +strings and then do kind of the right + + align:start position:0% +strings and then do kind of the right + + + align:start position:0% +strings and then do kind of the right +thing so basically this is saying get + + align:start position:0% +thing so basically this is saying get + + + align:start position:0% +thing so basically this is saying get +get me all columns that start with V so + + align:start position:0% +get me all columns that start with V so + + + align:start position:0% +get me all columns that start with V so +that will be all the vertices and this + + align:start position:0% +that will be all the vertices and this + + + align:start position:0% +that will be all the vertices and this +is the colon which says you know and I + + align:start position:0% +is the colon which says you know and I + + + align:start position:0% +is the colon which says you know and I +want the full row of + + align:start position:0% +want the full row of + + + align:start position:0% +want the full row of +that these had these values of um which + + align:start position:0% +that these had these values of um which + + + align:start position:0% +that these had these values of um which +were the the order group that they were + + align:start position:0% +were the the order group that they were + + + align:start position:0% +were the the order group that they were +in and uh and so we don't care about + + align:start position:0% +in and uh and so we don't care about + + + align:start position:0% +in and uh and so we don't care about +those we want to convert them back to + + align:start position:0% +those we want to convert them back to + + + align:start position:0% +those we want to convert them back to +regular numeric numbers and so we have + + align:start position:0% +regular numeric numbers and so we have + + + align:start position:0% +regular numeric numbers and so we have +this shorthand here called double Loi + + align:start position:0% +this shorthand here called double Loi + + + align:start position:0% +this shorthand here called double Loi +which basically just takes the logical + + align:start position:0% +which basically just takes the logical + + + align:start position:0% +which basically just takes the logical +and then does the double I think + + align:start position:0% +and then does the double I think + + + align:start position:0% +and then does the double I think +mathematically formally you would use + + align:start position:0% +mathematically formally you would use + + + align:start position:0% +mathematically formally you would use +call this the infinity Norm on strings + + align:start position:0% +call this the infinity Norm on strings + + + align:start position:0% +call this the infinity Norm on strings +if that even makes sense um but it + + align:start position:0% +if that even makes sense um but it + + + align:start position:0% +if that even makes sense um but it +basically just says if there's a value + + align:start position:0% +basically just says if there's a value + + + align:start position:0% +basically just says if there's a value +there convert it to a you know a double + + align:start position:0% +there convert it to a you know a double + + + align:start position:0% +there convert it to a you know a double +Precision one if there's not a value + + align:start position:0% +Precision one if there's not a value + + + align:start position:0% +Precision one if there's not a value +there it's just a sparse zero not not + + align:start position:0% +there it's just a sparse zero not not + + + align:start position:0% +there it's just a sparse zero not not +and we do this all the time because a + + align:start position:0% +and we do this all the time because a + + + align:start position:0% +and we do this all the time because a +lot of times we want to do math on these + + align:start position:0% +lot of times we want to do math on these + + + align:start position:0% +lot of times we want to do math on these +things it's like regular math uh we want + + align:start position:0% +things it's like regular math uh we want + + + align:start position:0% +things it's like regular math uh we want +to compute the vertex adjacency graph so + + align:start position:0% +to compute the vertex adjacency graph so + + + align:start position:0% +to compute the vertex adjacency graph so +we do that with our Square in function + + align:start position:0% +we do that with our Square in function + + + align:start position:0% +we do that with our Square in function +here our inner square product so that + + align:start position:0% +here our inner square product so that + + + align:start position:0% +here our inner square product so that +basically takes our Matrix and use the + + align:start position:0% +basically takes our Matrix and use the + + + align:start position:0% +basically takes our Matrix and use the +edge as the common key to to to join + + align:start position:0% +edge as the common key to to to join + + + align:start position:0% +edge as the common key to to to join +them together and we use our display + + align:start position:0% +them together and we use our display + + + align:start position:0% +them together and we use our display +full function to actually show what we + + align:start position:0% +full function to actually show what we + + + align:start position:0% +full function to actually show what we +got and so now you see the + + align:start position:0% +got and so now you see the + + + align:start position:0% +got and so now you see the +vertex vertex adjacency Matrix here and + + align:start position:0% +vertex vertex adjacency Matrix here and + + + align:start position:0% +vertex vertex adjacency Matrix here and +then the number is the number of times + + align:start position:0% +then the number is the number of times + + + align:start position:0% +then the number is the number of times +those vertices are on the same Edge so + + align:start position:0% +those vertices are on the same Edge so + + + align:start position:0% +those vertices are on the same Edge so +it's obviously symmetric and you see + + align:start position:0% +it's obviously symmetric and you see + + + align:start position:0% +it's obviously symmetric and you see +here some you know these vertices here + + align:start position:0% +here some you know these vertices here + + + align:start position:0% +here some you know these vertices here +which are part of this common hyper Edge + + align:start position:0% +which are part of this common hyper Edge + + + align:start position:0% +which are part of this common hyper Edge +you know we have this sort of 696 + + align:start position:0% +you know we have this sort of 696 + + + align:start position:0% +you know we have this sort of 696 +structure here various other types of + + align:start position:0% +structure here various other types of + + + align:start position:0% +structure here various other types of +symmetric structures going on here + + align:start position:0% +symmetric structures going on here + + + align:start position:0% +symmetric structures going on here +showing you the counts how many times + + align:start position:0% +showing you the counts how many times + + + align:start position:0% +showing you the counts how many times +those vertices appeared on the same Edge + + align:start position:0% +those vertices appeared on the same Edge + + + align:start position:0% +those vertices appeared on the same Edge +these are obviously clicks because they + + align:start position:0% +these are obviously clicks because they + + + align:start position:0% +these are obviously clicks because they +are all vertices that are on the same + + align:start position:0% +are all vertices that are on the same + + + align:start position:0% +are all vertices that are on the same +hyperedge line so if you have a same + + align:start position:0% +hyperedge line so if you have a same + + + align:start position:0% +hyperedge line so if you have a same +hyperedge line whenever you do the + + align:start position:0% +hyperedge line whenever you do the + + + align:start position:0% +hyperedge line whenever you do the +squaring operation + + align:start position:0% +squaring operation + + + align:start position:0% +squaring operation +you create you see it as this cck uh in + + align:start position:0% +you create you see it as this cck uh in + + + align:start position:0% +you create you see it as this cck uh in +this in this uh in this operation + + align:start position:0% + + + + align:start position:0% + +here + + align:start position:0% +here + + + align:start position:0% +here +right we can also do the square + + align:start position:0% +right we can also do the square + + + align:start position:0% +right we can also do the square +out + + align:start position:0% +out + + + align:start position:0% +out +function okay which computes The Edge + + align:start position:0% +function okay which computes The Edge + + + align:start position:0% +function okay which computes The Edge +adjacency Matrix so now we want to ask + + align:start position:0% +adjacency Matrix so now we want to ask + + + align:start position:0% +adjacency Matrix so now we want to ask +which edges share common + + align:start position:0% +which edges share common + + + align:start position:0% +which edges share common +vertices and so that's this structure + + align:start position:0% +vertices and so that's this structure + + + align:start position:0% +vertices and so that's this structure +here shows you the these are the various + + align:start position:0% +here shows you the these are the various + + + align:start position:0% +here shows you the these are the various +edges and again it's symmetric and you + + align:start position:0% +edges and again it's symmetric and you + + + align:start position:0% +edges and again it's symmetric and you +can see all kinds of structures in here + + align:start position:0% +can see all kinds of structures in here + + + align:start position:0% +can see all kinds of structures in here +about which vertices share I mean which + + align:start position:0% +about which vertices share I mean which + + + align:start position:0% +about which vertices share I mean which +edges share common common vertices so + + align:start position:0% +edges share common common vertices so + + + align:start position:0% +edges share common common vertices so +and that is pretty much it for this + + align:start position:0% +and that is pretty much it for this + + + align:start position:0% +and that is pretty much it for this +example very simple example uh hopefully + + align:start position:0% +example very simple example uh hopefully + + + align:start position:0% +example very simple example uh hopefully +gets you to the point where you can + + align:start position:0% +gets you to the point where you can + + + align:start position:0% +gets you to the point where you can +begin to try out the homework assignment + + align:start position:0% +begin to try out the homework assignment + + + align:start position:0% +begin to try out the homework assignment +and if there's any questions that people + + align:start position:0% +and if there's any questions that people + + + align:start position:0% +and if there's any questions that people +have you know uh you know let's try this + + align:start position:0% +have you know uh you know let's try this + + + align:start position:0% +have you know uh you know let's try this +here one thing that's fun to do spy + + align:start position:0% +here one thing that's fun to do spy + + + align:start position:0% +here one thing that's fun to do spy +e where that + + align:start position:0% + + + + align:start position:0% + +works + + align:start position:0% + + + + align:start position:0% + +oops come on gu I think between + + align:start position:0% +oops come on gu I think between + + + align:start position:0% +oops come on gu I think between +PowerPoint quick time and everything + + align:start position:0% +PowerPoint quick time and everything + + + align:start position:0% +PowerPoint quick time and everything +else it's just + + align:start position:0% +else it's just + + + align:start position:0% +else it's just +about ah there it is wow that took a + + align:start position:0% +about ah there it is wow that took a + + + align:start position:0% +about ah there it is wow that took a +long time so this shows that adjacency + + align:start position:0% +long time so this shows that adjacency + + + align:start position:0% +long time so this shows that adjacency +Matrix so spy works I think we I don't + + align:start position:0% +Matrix so spy works I think we I don't + + + align:start position:0% +Matrix so spy works I think we I don't +know if we showed that in the first + + align:start position:0% +know if we showed that in the first + + + align:start position:0% +know if we showed that in the first +example but the Spy function the + + align:start position:0% +example but the Spy function the + + + align:start position:0% +example but the Spy function the +standard M mat lab sparse plotting + + align:start position:0% +standard M mat lab sparse plotting + + + align:start position:0% +standard M mat lab sparse plotting +function very useful way to just sort of + + align:start position:0% +function very useful way to just sort of + + + align:start position:0% +function very useful way to just sort of +look at the stuff all those previous + + align:start position:0% +look at the stuff all those previous + + + align:start position:0% +look at the stuff all those previous +charts I showed you on the examples + + align:start position:0% +charts I showed you on the examples + + + align:start position:0% +charts I showed you on the examples +where we' done this thing and a little + + align:start position:0% +where we' done this thing and a little + + + align:start position:0% +where we' done this thing and a little +feature that sometimes causes mat lab to + + align:start position:0% +feature that sometimes causes mat lab to + + + align:start position:0% +feature that sometimes causes mat lab to +crash because it doesn't really like + + align:start position:0% +crash because it doesn't really like + + + align:start position:0% +crash because it doesn't really like +doing things too aggressively but if you + + align:start position:0% +doing things too aggressively but if you + + + align:start position:0% +doing things too aggressively but if you +click on + + align:start position:0% +click on + + + align:start position:0% +click on +it it shows you the row and the column + + align:start position:0% +it it shows you the row and the column + + + align:start position:0% +it it shows you the row and the column +and the value associated with that and + + align:start position:0% +and the value associated with that and + + + align:start position:0% +and the value associated with that and +also prints it out here likewise here so + + align:start position:0% +also prints it out here likewise here so + + + align:start position:0% +also prints it out here likewise here so +you see row column that gives you the + + align:start position:0% +you see row column that gives you the + + + align:start position:0% +you see row column that gives you the +order and this tells you you know the + + align:start position:0% +order and this tells you you know the + + + align:start position:0% +order and this tells you you know the +row is G2 its column is color its value + + align:start position:0% +row is G2 its column is color its value + + + align:start position:0% +row is G2 its column is color its value +is green so actually I lied to you that + + align:start position:0% +is green so actually I lied to you that + + + align:start position:0% +is green so actually I lied to you that +was just the first + + align:start position:0% +was just the first + + + align:start position:0% +was just the first +example see senior moment there we have + + align:start position:0% +example see senior moment there we have + + + align:start position:0% +example see senior moment there we have +two more to go a lot more fun see you're + + align:start position:0% +two more to go a lot more fun see you're + + + align:start position:0% +two more to go a lot more fun see you're +all you're all excited the class ended + + align:start position:0% +all you're all excited the class ended + + + align:start position:0% +all you're all excited the class ended +early so all right here's the other + + align:start position:0% +early so all right here's the other + + + align:start position:0% +early so all right here's the other +examples so again what we do is uh we're + + align:start position:0% +examples so again what we do is uh we're + + + align:start position:0% +examples so again what we do is uh we're +reading in the data set we're displaying + + align:start position:0% +reading in the data set we're displaying + + + align:start position:0% +reading in the data set we're displaying +the full thing so you can see there's + + align:start position:0% +the full thing so you can see there's + + + align:start position:0% +the full thing so you can see there's +the full Beast I just showed you with + + align:start position:0% +the full Beast I just showed you with + + + align:start position:0% +the full Beast I just showed you with +the Spy plot now I'm going to do some + + align:start position:0% +the Spy plot now I'm going to do some + + + align:start position:0% +the Spy plot now I'm going to do some +analytics on this so one thing I want to + + align:start position:0% +analytics on this so one thing I want to + + + align:start position:0% +analytics on this so one thing I want to +do is just get the orange edges so I can + + align:start position:0% +do is just get the orange edges so I can + + + align:start position:0% +do is just get the orange edges so I can +say get me the column + + align:start position:0% +say get me the column + + + align:start position:0% +say get me the column +color and because orange is held in the + + align:start position:0% +color and because orange is held in the + + + align:start position:0% +color and because orange is held in the +value I can actually compare it with the + + align:start position:0% +value I can actually compare it with the + + + align:start position:0% +value I can actually compare it with the +string so I say return me the Matrix the + + align:start position:0% +string so I say return me the Matrix the + + + align:start position:0% +string so I say return me the Matrix the +associative array of the row + + align:start position:0% +associative array of the row + + + align:start position:0% +associative array of the row +color and everything equal to Orange so + + align:start position:0% +color and everything equal to Orange so + + + align:start position:0% +color and everything equal to Orange so +that returns me another associative + + align:start position:0% +that returns me another associative + + + align:start position:0% +that returns me another associative +array the result of this whole logical + + align:start position:0% +array the result of this whole logical + + + align:start position:0% +array the result of this whole logical +expression is another associative array + + align:start position:0% +expression is another associative array + + + align:start position:0% +expression is another associative array +I can then get the rows of those + + align:start position:0% +I can then get the rows of those + + + align:start position:0% +I can then get the rows of those +associative arrays that associative + + align:start position:0% +associative arrays that associative + + + align:start position:0% +associative arrays that associative +array so I've found + + align:start position:0% +array so I've found + + + align:start position:0% +array so I've found +all + + align:start position:0% +all + + + align:start position:0% +all +um edges that are + + align:start position:0% +um edges that are + + + align:start position:0% +um edges that are +orange and I uh can then pass that get + + align:start position:0% +orange and I uh can then pass that get + + + align:start position:0% +orange and I uh can then pass that get +those rows and pass that back into the + + align:start position:0% +those rows and pass that back into the + + + align:start position:0% +those rows and pass that back into the +original one to get just the orange + + align:start position:0% +original one to get just the orange + + + align:start position:0% +original one to get just the orange +edges so this just shows you sort of + + align:start position:0% +edges so this just shows you sort of + + + align:start position:0% +edges so this just shows you sort of +this + + align:start position:0% +this + + + align:start position:0% +this +composable ability that's very powerful + + align:start position:0% +composable ability that's very powerful + + + align:start position:0% +composable ability that's very powerful +same same ability that mat lab has one + + align:start position:0% +same same ability that mat lab has one + + + align:start position:0% +same same ability that mat lab has one +does similar statements in mat lab all + + align:start position:0% +does similar statements in mat lab all + + + align:start position:0% +does similar statements in mat lab all +the time and so it's very composable + + align:start position:0% +the time and so it's very composable + + + align:start position:0% +the time and so it's very composable +this would be a very complex query to do + + align:start position:0% +this would be a very complex query to do + + + align:start position:0% +this would be a very complex query to do +in other approaches and you can do it + + align:start position:0% +in other approaches and you can do it + + + align:start position:0% +in other approaches and you can do it +very quickly here yes question + + align:start position:0% + + + + align:start position:0% + +to + + align:start position:0% +to + + + align:start position:0% +to +uh no it + + align:start position:0% +uh no it + + + align:start position:0% +uh no it +doesn't it doesn't what we could do is + + align:start position:0% +doesn't it doesn't what we could do is + + + align:start position:0% +doesn't it doesn't what we could do is +overload it so if you pass in an + + align:start position:0% +overload it so if you pass in an + + + align:start position:0% +overload it so if you pass in an +associative array with just a single + + align:start position:0% +associative array with just a single + + + align:start position:0% +associative array with just a single +argument and have it behave like when + + align:start position:0% +argument and have it behave like when + + + align:start position:0% +argument and have it behave like when +you pass in the mat lab logical and do + + align:start position:0% +you pass in the mat lab logical and do + + + align:start position:0% +you pass in the mat lab logical and do +that kind of intersection we could think + + align:start position:0% +that kind of intersection we could think + + + align:start position:0% +that kind of intersection we could think +about that but mat lab actually relies + + align:start position:0% +about that but mat lab actually relies + + + align:start position:0% +about that but mat lab actually relies +on then converting The Matrix to a + + align:start position:0% +on then converting The Matrix to a + + + align:start position:0% +on then converting The Matrix to a +vector and then using the + + align:start position:0% +vector and then using the + + + align:start position:0% +vector and then using the +singular basically it takes that logical + + align:start position:0% +singular basically it takes that logical + + + align:start position:0% +singular basically it takes that logical +converts it to a singular index which + + align:start position:0% +converts it to a singular index which + + + align:start position:0% +converts it to a singular index which +kind of gets us into an area where it's + + align:start position:0% +kind of gets us into an area where it's + + + align:start position:0% +kind of gets us into an area where it's +very fuzzy and gray so we've definitely + + align:start position:0% +very fuzzy and gray so we've definitely + + + align:start position:0% +very fuzzy and gray so we've definitely +thought about that and it's it's it's + + align:start position:0% +thought about that and it's it's it's + + + align:start position:0% +thought about that and it's it's it's +it's there are places where we line up + + align:start position:0% +it's there are places where we line up + + + align:start position:0% +it's there are places where we line up +with matab very nicely because the + + align:start position:0% +with matab very nicely because the + + + align:start position:0% +with matab very nicely because the +mathematics of associative arrays and + + align:start position:0% +mathematics of associative arrays and + + + align:start position:0% +mathematics of associative arrays and +linear algebra really line up very + + align:start position:0% +linear algebra really line up very + + + align:start position:0% +linear algebra really line up very +nicely and then there's there's there's + + align:start position:0% +nicely and then there's there's there's + + + align:start position:0% +nicely and then there's there's there's +and there's places where they intersect + + align:start position:0% +and there's places where they intersect + + + align:start position:0% +and there's places where they intersect +there's things you can do in with + + align:start position:0% +there's things you can do in with + + + align:start position:0% +there's things you can do in with +associative arrays that can't do with + + align:start position:0% +associative arrays that can't do with + + + align:start position:0% +associative arrays that can't do with +linear algebra for example we can mult + + align:start position:0% +linear algebra for example we can mult + + + align:start position:0% +linear algebra for example we can mult +Matrix multiply any two associative + + align:start position:0% +Matrix multiply any two associative + + + align:start position:0% +Matrix multiply any two associative +arrays there's no conformance + + align:start position:0% +arrays there's no conformance + + + align:start position:0% +arrays there's no conformance +requirement that they don't have the + + align:start position:0% +requirement that they don't have the + + + align:start position:0% +requirement that they don't have the +same normally when you multiply two + + align:start position:0% +same normally when you multiply two + + + align:start position:0% +same normally when you multiply two +matrices the number of the dimensions + + align:start position:0% +matrices the number of the dimensions + + + align:start position:0% +matrices the number of the dimensions +have to the inner Dimensions have to + + align:start position:0% +have to the inner Dimensions have to + + + align:start position:0% +have to the inner Dimensions have to +match basically The Columns of the left + + align:start position:0% +match basically The Columns of the left + + + align:start position:0% +match basically The Columns of the left +argument and the rows of the right + + align:start position:0% +argument and the rows of the right + + + align:start position:0% +argument and the rows of the right +argument must be the same length and + + align:start position:0% +argument must be the same length and + + + align:start position:0% +argument must be the same length and +Associate arrays that that requirement + + align:start position:0% +Associate arrays that that requirement + + + align:start position:0% +Associate arrays that that requirement +doesn't exist you can multiply or add + + align:start position:0% +doesn't exist you can multiply or add + + + align:start position:0% +doesn't exist you can multiply or add +any two associative arrays we'll get + + align:start position:0% +any two associative arrays we'll get + + + align:start position:0% +any two associative arrays we'll get +into that much more in the next class + + align:start position:0% +into that much more in the next class + + + align:start position:0% +into that much more in the next class +but that's a very powerful feature that + + align:start position:0% +but that's a very powerful feature that + + + align:start position:0% +but that's a very powerful feature that +people like but there's other places + + align:start position:0% +people like but there's other places + + + align:start position:0% +people like but there's other places +where it doesn't really make sense so uh + + align:start position:0% +where it doesn't really make sense so uh + + + align:start position:0% +where it doesn't really make sense so uh +things like what is the upper triangular + + align:start position:0% +things like what is the upper triangular + + + align:start position:0% +things like what is the upper triangular +section of an associative array gets to + + align:start position:0% +section of an associative array gets to + + + align:start position:0% +section of an associative array gets to +be a little bit huh what's that mean so + + align:start position:0% +be a little bit huh what's that mean so + + + align:start position:0% +be a little bit huh what's that mean so +excellent question though excellent + + align:start position:0% +excellent question though excellent + + + align:start position:0% +excellent question though excellent +question though so we can display this + + align:start position:0% +question though so we can display this + + + align:start position:0% +question though so we can display this +so this just shows we found all the + + align:start position:0% +so this just shows we found all the + + + align:start position:0% +so this just shows we found all the +edges that had color + + align:start position:0% +edges that had color + + + align:start position:0% +edges that had color +orange um but we don't have to just you + + align:start position:0% +orange um but we don't have to just you + + + align:start position:0% +orange um but we don't have to just you +know that's a way of using the values to + + align:start position:0% +know that's a way of using the values to + + + align:start position:0% +know that's a way of using the values to +select we could have of course used + + align:start position:0% +select we could have of course used + + + align:start position:0% +select we could have of course used +starts with in the rows just say starts + + align:start position:0% +starts with in the rows just say starts + + + align:start position:0% +starts with in the rows just say starts +with o and G I just happened to label + + align:start position:0% +with o and G I just happened to label + + + align:start position:0% +with o and G I just happened to label +all my rows that orange rows began with + + align:start position:0% +all my rows that orange rows began with + + + align:start position:0% +all my rows that orange rows began with +O and green rows begin with G so we can + + align:start position:0% +O and green rows begin with G so we can + + + align:start position:0% +O and green rows begin with G so we can +do starts with OG so that's example of + + align:start position:0% +do starts with OG so that's example of + + + align:start position:0% +do starts with OG so that's example of +those two range queries being done at + + align:start position:0% +those two range queries being done at + + + align:start position:0% +those two range queries being done at +the same time and so that gives us EOG + + align:start position:0% +the same time and so that gives us EOG + + + align:start position:0% +the same time and so that gives us EOG +and again we can see now we + + align:start position:0% +and again we can see now we + + + align:start position:0% +and again we can see now we +get the orange and green row + + align:start position:0% +get the orange and green row + + + align:start position:0% +get the orange and green row +so that just shows you that and then + + align:start position:0% +so that just shows you that and then + + + align:start position:0% +so that just shows you that and then +we'll wrap up here with the last example + + align:start position:0% +we'll wrap up here with the last example + + + align:start position:0% +we'll wrap up here with the last example +which is + + align:start position:0% + + + + align:start position:0% + +ea3 all right now we get to do some + + align:start position:0% +ea3 all right now we get to do some + + + align:start position:0% +ea3 all right now we get to do some +really fun stuff again we're reading in + + align:start position:0% +really fun stuff again we're reading in + + + align:start position:0% +really fun stuff again we're reading in +Reading in our data set converting just + + align:start position:0% +Reading in our data set converting just + + + align:start position:0% +Reading in our data set converting just +getting the + + align:start position:0% +getting the + + + align:start position:0% +getting the +vertices okay and then converting it to + + align:start position:0% +vertices okay and then converting it to + + + align:start position:0% +vertices okay and then converting it to +numeric zeros and ones I'm going to now + + align:start position:0% +numeric zeros and ones I'm going to now + + + align:start position:0% +numeric zeros and ones I'm going to now +just get the orange edges and I'm going + + align:start position:0% +just get the orange edges and I'm going + + + align:start position:0% +just get the orange edges and I'm going +to get the green + + align:start position:0% +to get the green + + + align:start position:0% +to get the green +edges all right and now I'm going to + + align:start position:0% +edges all right and now I'm going to + + + align:start position:0% +edges all right and now I'm going to +essentially do the + + align:start position:0% +essentially do the + + + align:start position:0% +essentially do the +crosscorrelation of the orange and green + + align:start position:0% +crosscorrelation of the orange and green + + + align:start position:0% +crosscorrelation of the orange and green +edges so I'm going to transpose one of + + align:start position:0% +edges so I'm going to transpose one of + + + align:start position:0% +edges so I'm going to transpose one of +them and Matrix multiply with the other + + align:start position:0% +them and Matrix multiply with the other + + + align:start position:0% +them and Matrix multiply with the other +ones we don't do Square in here because + + align:start position:0% +ones we don't do Square in here because + + + align:start position:0% +ones we don't do Square in here because +they're different matrices in fact I + + align:start position:0% +they're different matrices in fact I + + + align:start position:0% +they're different matrices in fact I +would say that people often do the cross + + align:start position:0% +would say that people often do the cross + + + align:start position:0% +would say that people often do the cross +correlation more often than they just + + align:start position:0% +correlation more often than they just + + + align:start position:0% +correlation more often than they just +Square The Matrix with itself you have + + align:start position:0% +Square The Matrix with itself you have + + + align:start position:0% +Square The Matrix with itself you have +one set with another set and you want to + + align:start position:0% +one set with another set and you want to + + + align:start position:0% +one set with another set and you want to +cross-correlate them a very common + + align:start position:0% +cross-correlate them a very common + + + align:start position:0% +cross-correlate them a very common +operation and so that's just transpose + + align:start position:0% +operation and so that's just transpose + + + align:start position:0% +operation and so that's just transpose +you know evg here and that gets + + align:start position:0% +you know evg here and that gets + + + align:start position:0% +you know evg here and that gets +that and as you can see the results of + + align:start position:0% +that and as you can see the results of + + + align:start position:0% +that and as you can see the results of +that inner product was + + align:start position:0% +that inner product was + + + align:start position:0% +that inner product was +empty all right but the result of the + + align:start position:0% +empty all right but the result of the + + + align:start position:0% +empty all right but the result of the +outer product is full so that just and + + align:start position:0% +outer product is full so that just and + + + align:start position:0% +outer product is full so that just and +you guys can think about why that + + align:start position:0% +you guys can think about why that + + + align:start position:0% +you guys can think about why that +is and so this just shows you the uh the + + align:start position:0% +is and so this just shows you the uh the + + + align:start position:0% +is and so this just shows you the uh the +uh the uh common how many um + + align:start position:0% +uh the uh common how many um + + + align:start position:0% +uh the uh common how many um +edges these appeared with + + align:start position:0% +edges these appeared with + + + align:start position:0% +edges these appeared with +together this shows you that there was + + align:start position:0% +together this shows you that there was + + + align:start position:0% +together this shows you that there was +no well you guys can figure that out + + align:start position:0% +no well you guys can figure that out + + + align:start position:0% +no well you guys can figure that out +I'll let you yeah now another thing that + + align:start position:0% +I'll let you yeah now another thing that + + + align:start position:0% +I'll let you yeah now another thing that +we often want to do is basically this + + align:start position:0% +we often want to do is basically this + + + align:start position:0% +we often want to do is basically this +showed us which um edges had common + + align:start position:0% +showed us which um edges had common + + + align:start position:0% +showed us which um edges had common +vertices you know shared vertices + + align:start position:0% +vertices you know shared vertices + + + align:start position:0% +vertices you know shared vertices +together okay but it didn't tell us we + + align:start position:0% +together okay but it didn't tell us we + + + align:start position:0% +together okay but it didn't tell us we +lost we lost the actual vertices we just + + align:start position:0% +lost we lost the actual vertices we just + + + align:start position:0% +lost we lost the actual vertices we just +know that there's three and a lot of + + align:start position:0% +know that there's three and a lot of + + + align:start position:0% +know that there's three and a lot of +times we want them this is sometimes + + align:start position:0% +times we want them this is sometimes + + + align:start position:0% +times we want them this is sometimes +called the pedigree you do a correlation + + align:start position:0% +called the pedigree you do a correlation + + + align:start position:0% +called the pedigree you do a correlation +and then you would like but but you say + + align:start position:0% +and then you would like but but you say + + + align:start position:0% +and then you would like but but you say +these two things are correlated I want + + align:start position:0% +these two things are correlated I want + + + align:start position:0% +these two things are correlated I want +to get the the connector back to the + + align:start position:0% +to get the the connector back to the + + + align:start position:0% +to get the the connector back to the +original record so I can go back to my e + + align:start position:0% +original record so I can go back to my e + + + align:start position:0% +original record so I can go back to my e +Matrix and really find that out and + + align:start position:0% +Matrix and really find that out and + + + align:start position:0% +Matrix and really find that out and +present that as the evidence that these + + align:start position:0% +present that as the evidence that these + + + align:start position:0% +present that as the evidence that these +things are connected together and we + + align:start position:0% +things are connected together and we + + + align:start position:0% +things are connected together and we +don't want to lose that so we have + + align:start position:0% +don't want to lose that so we have + + + align:start position:0% +don't want to lose that so we have +invented special new Matrix + + align:start position:0% +invented special new Matrix + + + align:start position:0% +invented special new Matrix +multiplies in the land of associative + + align:start position:0% +multiplies in the land of associative + + + align:start position:0% +multiplies in the land of associative +arrays one of them we call Cat key mul + + align:start position:0% +arrays one of them we call Cat key mul + + + align:start position:0% +arrays one of them we call Cat key mul +okay okay which if you view the Matrix + + align:start position:0% +okay okay which if you view the Matrix + + + align:start position:0% +okay okay which if you view the Matrix +multiply as sort of there's a key a + + align:start position:0% +multiply as sort of there's a key a + + + align:start position:0% +multiply as sort of there's a key a +common key this row column key that's + + align:start position:0% +common key this row column key that's + + + align:start position:0% +common key this row column key that's +being sort of joined together well we + + align:start position:0% +being sort of joined together well we + + + align:start position:0% +being sort of joined together well we +can preserve that and store that in the + + align:start position:0% +can preserve that and store that in the + + + align:start position:0% +can preserve that and store that in the +value instead of say the count or + + align:start position:0% +value instead of say the count or + + + align:start position:0% +value instead of say the count or +something like that so we do cat key + + align:start position:0% +something like that so we do cat key + + + align:start position:0% +something like that so we do cat key +mole ev0 transpose evg and then when we + + align:start position:0% +mole ev0 transpose evg and then when we + + + align:start position:0% +mole ev0 transpose evg and then when we +display that we not only + + align:start position:0% +display that we not only + + + align:start position:0% +display that we not only +see which edges were connected but we + + align:start position:0% +see which edges were connected but we + + + align:start position:0% +see which edges were connected but we +also have preserved + + align:start position:0% +also have preserved + + + align:start position:0% +also have preserved +the list of the vertices is essentially + + align:start position:0% +the list of the vertices is essentially + + + align:start position:0% +the list of the vertices is essentially +a concatenated list of those keys very + + align:start position:0% +a concatenated list of those keys very + + + align:start position:0% +a concatenated list of those keys very +useful thing + + align:start position:0% +useful thing + + + align:start position:0% +useful thing +um one has to be so very powerful + + align:start position:0% +um one has to be so very powerful + + + align:start position:0% +um one has to be so very powerful +Technique One definitely has to be + + align:start position:0% +Technique One definitely has to be + + + align:start position:0% +Technique One definitely has to be +careful about using this technique if it + + align:start position:0% +careful about using this technique if it + + + align:start position:0% +careful about using this technique if it +generate it's going to generate + + align:start position:0% +generate it's going to generate + + + align:start position:0% +generate it's going to generate +extremely oops extremely long lists here + + align:start position:0% +extremely oops extremely long lists here + + + align:start position:0% +extremely oops extremely long lists here +that can really cause this to behave + + align:start position:0% +that can really cause this to behave + + + align:start position:0% +that can really cause this to behave +very slowly uh in particular one has to + + align:start position:0% +very slowly uh in particular one has to + + + align:start position:0% +very slowly uh in particular one has to +be careful of if you do a cat key mole + + align:start position:0% +be careful of if you do a cat key mole + + + align:start position:0% +be careful of if you do a cat key mole +on a matrix with itself why do you think + + align:start position:0% +on a matrix with itself why do you think + + + align:start position:0% +on a matrix with itself why do you think +you would have to be careful with that + + align:start position:0% +you would have to be careful with that + + + align:start position:0% +you would have to be careful with that +anyone remember that dense diagonal that + + align:start position:0% +anyone remember that dense diagonal that + + + align:start position:0% +anyone remember that dense diagonal that +happened whenever we squared matrices so + + align:start position:0% +happened whenever we squared matrices so + + + align:start position:0% +happened whenever we squared matrices so +that means this thing will have an + + align:start position:0% +that means this thing will have an + + + align:start position:0% +that means this thing will have an +enormous number of entries along the + + align:start position:0% +enormous number of entries along the + + + align:start position:0% +enormous number of entries along the +diagonal so you have to be very careful + + align:start position:0% +diagonal so you have to be very careful + + + align:start position:0% +diagonal so you have to be very careful +when you use this kind of function to + + align:start position:0% +when you use this kind of function to + + + align:start position:0% +when you use this kind of function to +correlate something with itself it's + + align:start position:0% +correlate something with itself it's + + + align:start position:0% +correlate something with itself it's +better to correlate two distinct sets + + align:start position:0% +better to correlate two distinct sets + + + align:start position:0% +better to correlate two distinct sets +because they tend to not have that that + + align:start position:0% +because they tend to not have that that + + + align:start position:0% +because they tend to not have that that +dense diagonal which can be a little bit + + align:start position:0% +dense diagonal which can be a little bit + + + align:start position:0% +dense diagonal which can be a little bit +of a problem there's ways to get around + + align:start position:0% +of a problem there's ways to get around + + + align:start position:0% +of a problem there's ways to get around +that I mean there's hacks and tricks and + + align:start position:0% +that I mean there's hacks and tricks and + + + align:start position:0% +that I mean there's hacks and tricks and +stuff like that but at a certain level + + align:start position:0% +stuff like that but at a certain level + + + align:start position:0% +stuff like that but at a certain level +really dense diagonals I mean you + + align:start position:0% +really dense diagonals I mean you + + + align:start position:0% +really dense diagonals I mean you +essentially be listing every single + + align:start position:0% +essentially be listing every single + + + align:start position:0% +essentially be listing every single +vertex in your data set you could be + + align:start position:0% +vertex in your data set you could be + + + align:start position:0% +vertex in your data set you could be +listing every single vertex in your data + + align:start position:0% +listing every single vertex in your data + + + align:start position:0% +listing every single vertex in your data +set almost every single time you know + + align:start position:0% +set almost every single time you know + + + align:start position:0% +set almost every single time you know +multiple times along the diagonal that + + align:start position:0% +multiple times along the diagonal that + + + align:start position:0% +multiple times along the diagonal that +would be get very very bulky so just a + + align:start position:0% +would be get very very bulky so just a + + + align:start position:0% +would be get very very bulky so just a +little word of caution there and so now + + align:start position:0% +little word of caution there and so now + + + align:start position:0% +little word of caution there and so now +i' I've baited you once but this really + + align:start position:0% +i' I've baited you once but this really + + + align:start position:0% +i' I've baited you once but this really +is the end so um are there any questions + + align:start position:0% +is the end so um are there any questions + + + align:start position:0% +is the end so um are there any questions +on the examples before we cut it off + + align:start position:0% +on the examples before we cut it off + + + align:start position:0% +on the examples before we cut it off +here was there a question back here + + align:start position:0% +here was there a question back here + + + align:start position:0% +here was there a question back here +somewhere + + align:start position:0% +somewhere + + + align:start position:0% +somewhere +no all right great thank you very much I + + align:start position:0% +no all right great thank you very much I + + + align:start position:0% +no all right great thank you very much I +appreciate it and we'll see you next + + align:start position:0% +appreciate it and we'll see you next + + + align:start position:0% +appreciate it and we'll see you next +week and uh again think of a picture + + align:start position:0% +week and uh again think of a picture + + + align:start position:0% +week and uh again think of a picture +draw some lines make an incidence + + align:start position:0% +draw some lines make an incidence + + + align:start position:0% +draw some lines make an incidence +Matrix have fun with + + align:start position:0% +Matrix have fun with + + + align:start position:0% +Matrix have fun with +it compute the degree of your + + align:start position:0% +it compute the degree of your + + + align:start position:0% +it compute the degree of your +significant + + align:start position:0% +significant + + + align:start position:0% +significant +other idea bad idea yeah + + align:start position:0% + + + + align:start position:0% + +good \ No newline at end of file diff --git a/6S3BJSsc72Q.txt b/6S3BJSsc72Q.txt new file mode 100644 index 0000000000000000000000000000000000000000..06d4f7424fc2636c0e50c73d6d015d0890e13f9d --- /dev/null +++ b/6S3BJSsc72Q.txt @@ -0,0 +1,3011 @@ +align:start position:0% + +welcome back to recitation in this video + + align:start position:0% +welcome back to recitation in this video + + + align:start position:0% +welcome back to recitation in this video +what I'd like us to do is work on + + align:start position:0% +what I'd like us to do is work on + + + align:start position:0% +what I'd like us to do is work on +understanding Simply Connected regions + + align:start position:0% +understanding Simply Connected regions + + + align:start position:0% +understanding Simply Connected regions +in three dimensions well there's one + + align:start position:0% +in three dimensions well there's one + + + align:start position:0% +in three dimensions well there's one +two-dimensional one but the rest are + + align:start position:0% +two-dimensional one but the rest are + + + align:start position:0% +two-dimensional one but the rest are +three dimensions so what I want you to + + align:start position:0% +three dimensions so what I want you to + + + align:start position:0% +three dimensions so what I want you to +do is for each of the following there + + align:start position:0% +do is for each of the following there + + + align:start position:0% +do is for each of the following there +are six different regions determine + + align:start position:0% +are six different regions determine + + + align:start position:0% +are six different regions determine +whether or not each of them is Simply + + align:start position:0% +whether or not each of them is Simply + + + align:start position:0% +whether or not each of them is Simply +Connected so the first one is R3 the + + align:start position:0% +Connected so the first one is R3 the + + + align:start position:0% +Connected so the first one is R3 the +second one is if I take R3 and I remove + + align:start position:0% +second one is if I take R3 and I remove + + + align:start position:0% +second one is if I take R3 and I remove +the entire Z axis the third one is if I + + align:start position:0% +the entire Z axis the third one is if I + + + align:start position:0% +the entire Z axis the third one is if I +take R3 and I remove zero the fourth one + + align:start position:0% +take R3 and I remove zero the fourth one + + + align:start position:0% +take R3 and I remove zero the fourth one +is if I take R3 and remove a + + align:start position:0% +is if I take R3 and remove a + + + align:start position:0% +is if I take R3 and remove a +circle sorry the fourth yeah the fourth + + align:start position:0% +circle sorry the fourth yeah the fourth + + + align:start position:0% +circle sorry the fourth yeah the fourth +one the fifth one is R2 minus a line + + align:start position:0% +one the fifth one is R2 minus a line + + + align:start position:0% +one the fifth one is R2 minus a line +segment and the sixth one is a solid + + align:start position:0% +segment and the sixth one is a solid + + + align:start position:0% +segment and the sixth one is a solid +Taurus so a solid Taurus is it looks + + align:start position:0% +Taurus so a solid Taurus is it looks + + + align:start position:0% +Taurus so a solid Taurus is it looks +like a donut and it includes the the + + align:start position:0% +like a donut and it includes the the + + + align:start position:0% +like a donut and it includes the the +inside of the donut so hopefully you can + + align:start position:0% +inside of the donut so hopefully you can + + + align:start position:0% +inside of the donut so hopefully you can +see this looks like a donut hopefully to + + align:start position:0% +see this looks like a donut hopefully to + + + align:start position:0% +see this looks like a donut hopefully to +you and it's it's not Hollow it includes + + align:start position:0% +you and it's it's not Hollow it includes + + + align:start position:0% +you and it's it's not Hollow it includes +the inside so what I'd like you to do + + align:start position:0% +the inside so what I'd like you to do + + + align:start position:0% +the inside so what I'd like you to do +again is determine whether or not each + + align:start position:0% +again is determine whether or not each + + + align:start position:0% +again is determine whether or not each +of these regions is Simply Connected and + + align:start position:0% +of these regions is Simply Connected and + + + align:start position:0% +of these regions is Simply Connected and +uh and why don't you pause the video + + align:start position:0% +uh and why don't you pause the video + + + align:start position:0% +uh and why don't you pause the video +while you work on that and then bring + + align:start position:0% +while you work on that and then bring + + + align:start position:0% +while you work on that and then bring +the video back up when you're ready to + + align:start position:0% +the video back up when you're ready to + + + align:start position:0% +the video back up when you're ready to +check your + + align:start position:0% + + + + align:start position:0% + +work okay welcome back so again what + + align:start position:0% +work okay welcome back so again what + + + align:start position:0% +work okay welcome back so again what +we're interested in doing is + + align:start position:0% +we're interested in doing is + + + align:start position:0% +we're interested in doing is +understanding simply connectedness in + + align:start position:0% +understanding simply connectedness in + + + align:start position:0% +understanding simply connectedness in +another dimension we did something + + align:start position:0% +another dimension we did something + + + align:start position:0% +another dimension we did something +already a while back with two dimensions + + align:start position:0% +already a while back with two dimensions + + + align:start position:0% +already a while back with two dimensions +and so now we want to understand it + + align:start position:0% +and so now we want to understand it + + + align:start position:0% +and so now we want to understand it +better in three dimensions so let's + + align:start position:0% +better in three dimensions so let's + + + align:start position:0% +better in three dimensions so let's +let's work through these well I'm not + + align:start position:0% +let's work through these well I'm not + + + align:start position:0% +let's work through these well I'm not +going to write anything down for number + + align:start position:0% +going to write anything down for number + + + align:start position:0% +going to write anything down for number +one because you should already know that + + align:start position:0% +one because you should already know that + + + align:start position:0% +one because you should already know that +R3 is Simply Connected but if you + + align:start position:0% +R3 is Simply Connected but if you + + + align:start position:0% +R3 is Simply Connected but if you +weren't sure about it you could think + + align:start position:0% +weren't sure about it you could think + + + align:start position:0% +weren't sure about it you could think +any any closed curve I draw in R3 I can + + align:start position:0% +any any closed curve I draw in R3 I can + + + align:start position:0% +any any closed curve I draw in R3 I can +certainly get all of the inside of it + + align:start position:0% +certainly get all of the inside of it + + + align:start position:0% +certainly get all of the inside of it +contained in R3 another way to think + + align:start position:0% +contained in R3 another way to think + + + align:start position:0% +contained in R3 another way to think +about it is that I can take that curve + + align:start position:0% +about it is that I can take that curve + + + align:start position:0% +about it is that I can take that curve +and I can collapse it down to a point + + align:start position:0% +and I can collapse it down to a point + + + align:start position:0% +and I can collapse it down to a point +and remain in R3 but let's start on so + + align:start position:0% +and remain in R3 but let's start on so + + + align:start position:0% +and remain in R3 but let's start on so +the first one is an easy yes to Simply + + align:start position:0% +the first one is an easy yes to Simply + + + align:start position:0% +the first one is an easy yes to Simply +connectedness okay so let's start on the + + align:start position:0% +connectedness okay so let's start on the + + + align:start position:0% +connectedness okay so let's start on the +second one and I'm going to draw a + + align:start position:0% +second one and I'm going to draw a + + + align:start position:0% +second one and I'm going to draw a +little picture for us so the second one + + align:start position:0% +little picture for us so the second one + + + align:start position:0% +little picture for us so the second one +is + + align:start position:0% +is + + + align:start position:0% +is +R3 oops R3 I should go this way this is + + align:start position:0% +R3 oops R3 I should go this way this is + + + align:start position:0% +R3 oops R3 I should go this way this is +XYZ but then I remove the entire z-axis + + align:start position:0% +XYZ but then I remove the entire z-axis + + + align:start position:0% +XYZ but then I remove the entire z-axis +so I should make this real dark so we + + align:start position:0% +so I should make this real dark so we + + + align:start position:0% +so I should make this real dark so we +know this stuff + + align:start position:0% +know this stuff + + + align:start position:0% +know this stuff +is we're removing that part from R3 and + + align:start position:0% +is we're removing that part from R3 and + + + align:start position:0% +is we're removing that part from R3 and +I'm removing it all the way up to minus + + align:start position:0% +I'm removing it all the way up to minus + + + align:start position:0% +I'm removing it all the way up to minus +minus Infinity in the Z Direction and + + align:start position:0% +minus Infinity in the Z Direction and + + + align:start position:0% +minus Infinity in the Z Direction and +plus infinity in the Z Direction now the + + align:start position:0% +plus infinity in the Z Direction now the + + + align:start position:0% +plus infinity in the Z Direction now the +question is can I find any closed curve + + align:start position:0% +question is can I find any closed curve + + + align:start position:0% +question is can I find any closed curve +that when I try and try and compress + + align:start position:0% +that when I try and try and compress + + + align:start position:0% +that when I try and try and compress +that closed curve down to a point I + + align:start position:0% +that closed curve down to a point I + + + align:start position:0% +that closed curve down to a point I +can't do it while remaining inside this + + align:start position:0% +can't do it while remaining inside this + + + align:start position:0% +can't do it while remaining inside this +region that is all of our three minus + + align:start position:0% +region that is all of our three minus + + + align:start position:0% +region that is all of our three minus +the z-axis and the answer is there is a + + align:start position:0% +the z-axis and the answer is there is a + + + align:start position:0% +the z-axis and the answer is there is a +whole family of curves that do this if I + + align:start position:0% +whole family of curves that do this if I + + + align:start position:0% +whole family of curves that do this if I +take a curve that goes around the + + align:start position:0% + + + + align:start position:0% + +z-axis you'll notice that there's + + align:start position:0% +z-axis you'll notice that there's + + + align:start position:0% +z-axis you'll notice that there's +something on the inside of it regardless + + align:start position:0% +something on the inside of it regardless + + + align:start position:0% +something on the inside of it regardless +of you know if I slide it up or down + + align:start position:0% +of you know if I slide it up or down + + + align:start position:0% +of you know if I slide it up or down +there's a point on the inside of this + + align:start position:0% +there's a point on the inside of this + + + align:start position:0% +there's a point on the inside of this +this curve that is not in the region I'm + + align:start position:0% +this curve that is not in the region I'm + + + align:start position:0% +this curve that is not in the region I'm +interested in the region again is R3 + + align:start position:0% +interested in the region again is R3 + + + align:start position:0% +interested in the region again is R3 +minus the z-axis so there's two ways to + + align:start position:0% +minus the z-axis so there's two ways to + + + align:start position:0% +minus the z-axis so there's two ways to +think about this you can think about you + + align:start position:0% +think about this you can think about you + + + align:start position:0% +think about this you can think about you +know if I were to take this curve and I + + align:start position:0% +know if I were to take this curve and I + + + align:start position:0% +know if I were to take this curve and I +were to to put a surface across this + + align:start position:0% +were to to put a surface across this + + + align:start position:0% +were to to put a surface across this +curve so it was like a disc there would + + align:start position:0% +curve so it was like a disc there would + + + align:start position:0% +curve so it was like a disc there would +be a point on the z-axis that would + + align:start position:0% +be a point on the z-axis that would + + + align:start position:0% +be a point on the z-axis that would +intersect it or you can think about it + + align:start position:0% +intersect it or you can think about it + + + align:start position:0% +intersect it or you can think about it +as saying I have this curve and if I try + + align:start position:0% +as saying I have this curve and if I try + + + align:start position:0% +as saying I have this curve and if I try +and squeeze it down to to a to as small + + align:start position:0% +and squeeze it down to to a to as small + + + align:start position:0% +and squeeze it down to to a to as small +as I can get it I can't get it as small + + align:start position:0% +as I can get it I can't get it as small + + + align:start position:0% +as I can get it I can't get it as small +as I want without hitting the Z axis at + + align:start position:0% +as I want without hitting the Z axis at + + + align:start position:0% +as I want without hitting the Z axis at +some point I'm always going to have the + + align:start position:0% +some point I'm always going to have the + + + align:start position:0% +some point I'm always going to have the +z-axis is kind of in the way + + align:start position:0% +z-axis is kind of in the way + + + align:start position:0% +z-axis is kind of in the way +right now uh number three is a little + + align:start position:0% +right now uh number three is a little + + + align:start position:0% +right now uh number three is a little +different situation because number three + + align:start position:0% +different situation because number three + + + align:start position:0% +different situation because number three +I take this exact same picture but + + align:start position:0% +I take this exact same picture but + + + align:start position:0% +I take this exact same picture but +instead of removing the whole z- axis I + + align:start position:0% +instead of removing the whole z- axis I + + + align:start position:0% +instead of removing the whole z- axis I +just remove the origin so let me try and + + align:start position:0% +just remove the origin so let me try and + + + align:start position:0% +just remove the origin so let me try and +draw a picture of + + align:start position:0% +draw a picture of + + + align:start position:0% +draw a picture of +that so I'm going to make this there's a + + align:start position:0% +that so I'm going to make this there's a + + + align:start position:0% +that so I'm going to make this there's a +big open circle at the origin that's not + + align:start position:0% +big open circle at the origin that's not + + + align:start position:0% +big open circle at the origin that's not +included in in our domain in our + + align:start position:0% +included in in our domain in our + + + align:start position:0% +included in in our domain in our +region so our region is all of our three + + align:start position:0% +region so our region is all of our three + + + align:start position:0% +region so our region is all of our three +except the origin + + align:start position:0% +except the origin + + + align:start position:0% +except the origin +and in two-dimensional space this was + + align:start position:0% +and in two-dimensional space this was + + + align:start position:0% +and in two-dimensional space this was +not Simply Connected but in + + align:start position:0% +not Simply Connected but in + + + align:start position:0% +not Simply Connected but in +three-dimensional space it is simply + + align:start position:0% +three-dimensional space it is simply + + + align:start position:0% +three-dimensional space it is simply +connected so this is a little different + + align:start position:0% +connected so this is a little different + + + align:start position:0% +connected so this is a little different +situation than what you had previously + + align:start position:0% +situation than what you had previously + + + align:start position:0% +situation than what you had previously +and so the idea is here if I take a + + align:start position:0% +and so the idea is here if I take a + + + align:start position:0% +and so the idea is here if I take a +curve even if I take a curve that's kind + + align:start position:0% +curve even if I take a curve that's kind + + + align:start position:0% +curve even if I take a curve that's kind +of sitting in the XY plane that goes + + align:start position:0% +of sitting in the XY plane that goes + + + align:start position:0% +of sitting in the XY plane that goes +around the origin the point is I can + + align:start position:0% +around the origin the point is I can + + + align:start position:0% +around the origin the point is I can +keep this curve in three-dimensional + + align:start position:0% +keep this curve in three-dimensional + + + align:start position:0% +keep this curve in three-dimensional +space and I can wiggle it around so that + + align:start position:0% +space and I can wiggle it around so that + + + align:start position:0% +space and I can wiggle it around so that +I can shrink it down to a point and the + + align:start position:0% +I can shrink it down to a point and the + + + align:start position:0% +I can shrink it down to a point and the +origin doesn't get in the way it doesn't + + align:start position:0% +origin doesn't get in the way it doesn't + + + align:start position:0% +origin doesn't get in the way it doesn't +keep me from doing that okay it doesn't + + align:start position:0% +keep me from doing that okay it doesn't + + + align:start position:0% +keep me from doing that okay it doesn't +keep me from doing that so this actually + + align:start position:0% +keep me from doing that so this actually + + + align:start position:0% +keep me from doing that so this actually +this region even though in + + align:start position:0% +this region even though in + + + align:start position:0% +this region even though in +two-dimensional space it was not Simply + + align:start position:0% +two-dimensional space it was not Simply + + + align:start position:0% +two-dimensional space it was not Simply +Connected in threedimensional space it + + align:start position:0% +Connected in threedimensional space it + + + align:start position:0% +Connected in threedimensional space it +is and let's see if we understand the + + align:start position:0% +is and let's see if we understand the + + + align:start position:0% +is and let's see if we understand the +difference the difference is in + + align:start position:0% +difference the difference is in + + + align:start position:0% +difference the difference is in +two-dimensional space if I drew a curve + + align:start position:0% +two-dimensional space if I drew a curve + + + align:start position:0% +two-dimensional space if I drew a curve +on the XY plane and I around the origin + + align:start position:0% +on the XY plane and I around the origin + + + align:start position:0% +on the XY plane and I around the origin +and I wanted to squish it down to a + + align:start position:0% +and I wanted to squish it down to a + + + align:start position:0% +and I wanted to squish it down to a +point the only way to do that would be + + align:start position:0% +point the only way to do that would be + + + align:start position:0% +point the only way to do that would be +to bring the curve somehow through the + + align:start position:0% +to bring the curve somehow through the + + + align:start position:0% +to bring the curve somehow through the +origin right I would be stuck having to + + align:start position:0% +origin right I would be stuck having to + + + align:start position:0% +origin right I would be stuck having to +pass the curve through the origin to + + align:start position:0% +pass the curve through the origin to + + + align:start position:0% +pass the curve through the origin to +shrink it down to a point + + align:start position:0% +shrink it down to a point + + + align:start position:0% +shrink it down to a point +but in three space I have another + + align:start position:0% +but in three space I have another + + + align:start position:0% +but in three space I have another +dimension so a curve that sits on the XY + + align:start position:0% +dimension so a curve that sits on the XY + + + align:start position:0% +dimension so a curve that sits on the XY +plane I can just kind of lift it a + + align:start position:0% +plane I can just kind of lift it a + + + align:start position:0% +plane I can just kind of lift it a +little bit away from the origin and then + + align:start position:0% +little bit away from the origin and then + + + align:start position:0% +little bit away from the origin and then +I can shink it down to a point without + + align:start position:0% +I can shink it down to a point without + + + align:start position:0% +I can shink it down to a point without +without getting the origin getting in + + align:start position:0% +without getting the origin getting in + + + align:start position:0% +without getting the origin getting in +the way so having that extra Dimension + + align:start position:0% +the way so having that extra Dimension + + + align:start position:0% +the way so having that extra Dimension +means even though I remove one point + + align:start position:0% +means even though I remove one point + + + align:start position:0% +means even though I remove one point +it's still actually a Simply Connected + + align:start position:0% +it's still actually a Simply Connected + + + align:start position:0% +it's still actually a Simply Connected +region so this is maybe this is the + + align:start position:0% +region so this is maybe this is the + + + align:start position:0% +region so this is maybe this is the +first place we see that the third three + + align:start position:0% +first place we see that the third three + + + align:start position:0% +first place we see that the third three +dimensions we have a different case than + + align:start position:0% +dimensions we have a different case than + + + align:start position:0% +dimensions we have a different case than +we had uh in two Dimensions removing the + + align:start position:0% +we had uh in two Dimensions removing the + + + align:start position:0% +we had uh in two Dimensions removing the +same kind of object so I realize now I + + align:start position:0% +same kind of object so I realize now I + + + align:start position:0% +same kind of object so I realize now I +haven't been writing down whether these + + align:start position:0% +haven't been writing down whether these + + + align:start position:0% +haven't been writing down whether these +are Simply Connected or or not so I + + align:start position:0% +are Simply Connected or or not so I + + + align:start position:0% +are Simply Connected or or not so I +should write down this as Simply + + align:start position:0% +should write down this as Simply + + + align:start position:0% +should write down this as Simply +Connected and maybe for number two I + + align:start position:0% +Connected and maybe for number two I + + + align:start position:0% +Connected and maybe for number two I +should go back and formally right you + + align:start position:0% +should go back and formally right you + + + align:start position:0% +should go back and formally right you +know not simply connecting so that we + + align:start position:0% +know not simply connecting so that we + + + align:start position:0% +know not simply connecting so that we +have this for + + align:start position:0% +have this for + + + align:start position:0% +have this for +posterity now the fourth one is R3 minus + + align:start position:0% +posterity now the fourth one is R3 minus + + + align:start position:0% +posterity now the fourth one is R3 minus +a circle so let me see if I can draw a + + align:start position:0% +a circle so let me see if I can draw a + + + align:start position:0% +a circle so let me see if I can draw a +picture of + + align:start position:0% +picture of + + + align:start position:0% +picture of +that and the circle it doesn't really + + align:start position:0% +that and the circle it doesn't really + + + align:start position:0% +that and the circle it doesn't really +matter where it + + align:start position:0% +matter where it + + + align:start position:0% +matter where it +is I'm just going to draw one + + align:start position:0% +is I'm just going to draw one + + + align:start position:0% +is I'm just going to draw one +somewhere so I'll draw a circle say + + align:start position:0% +somewhere so I'll draw a circle say + + + align:start position:0% +somewhere so I'll draw a circle say +here's my circle so everything is in my + + align:start position:0% +here's my circle so everything is in my + + + align:start position:0% +here's my circle so everything is in my +region except this circle and the + + align:start position:0% +region except this circle and the + + + align:start position:0% +region except this circle and the +question is is it Simply Connected and + + align:start position:0% +question is is it Simply Connected and + + + align:start position:0% +question is is it Simply Connected and +the answer is no the region is not + + align:start position:0% +the answer is no the region is not + + + align:start position:0% +the answer is no the region is not +Simply Connected because of one + + align:start position:0% +Simply Connected because of one + + + align:start position:0% +Simply Connected because of one +particular problem it's actually the + + align:start position:0% +particular problem it's actually the + + + align:start position:0% +particular problem it's actually the +same kind of problem you have when you + + align:start position:0% +same kind of problem you have when you + + + align:start position:0% +same kind of problem you have when you +remove the z-axis and that is if I draw + + align:start position:0% +remove the z-axis and that is if I draw + + + align:start position:0% +remove the z-axis and that is if I draw +a curve that goes around this + + align:start position:0% +a curve that goes around this + + + align:start position:0% +a curve that goes around this +circle right any curve that goes around + + align:start position:0% +circle right any curve that goes around + + + align:start position:0% +circle right any curve that goes around +this + + align:start position:0% +this + + + align:start position:0% +this +circle notice that any way I try and + + align:start position:0% +circle notice that any way I try and + + + align:start position:0% +circle notice that any way I try and +move this curve curve and and shrink it + + align:start position:0% +move this curve curve and and shrink it + + + align:start position:0% +move this curve curve and and shrink it +down to a point this circle is going to + + align:start position:0% +down to a point this circle is going to + + + align:start position:0% +down to a point this circle is going to +get in the way for the same reason that + + align:start position:0% +get in the way for the same reason that + + + align:start position:0% +get in the way for the same reason that +the z-axis got in the way because this + + align:start position:0% +the z-axis got in the way because this + + + align:start position:0% +the z-axis got in the way because this +circle is closed I can't like Slide the + + align:start position:0% +circle is closed I can't like Slide the + + + align:start position:0% +circle is closed I can't like Slide the +the the curve I'm interested in away + + align:start position:0% +the the curve I'm interested in away + + + align:start position:0% +the the curve I'm interested in away +from the away from the circle and then + + align:start position:0% +from the away from the circle and then + + + align:start position:0% +from the away from the circle and then +shrink it down okay there's there's some + + align:start position:0% +shrink it down okay there's there's some + + + align:start position:0% +shrink it down okay there's there's some +sort of obstruction right here and so + + align:start position:0% +sort of obstruction right here and so + + + align:start position:0% +sort of obstruction right here and so +it's fundamentally different than the + + align:start position:0% +it's fundamentally different than the + + + align:start position:0% +it's fundamentally different than the +case where we just had the origin + + align:start position:0% +case where we just had the origin + + + align:start position:0% +case where we just had the origin +because we could take any curve and we + + align:start position:0% +because we could take any curve and we + + + align:start position:0% +because we could take any curve and we +could move it away from the origin and + + align:start position:0% +could move it away from the origin and + + + align:start position:0% +could move it away from the origin and +then shrink it down to a point and the + + align:start position:0% +then shrink it down to a point and the + + + align:start position:0% +then shrink it down to a point and the +origin didn't get in the way but here + + align:start position:0% +origin didn't get in the way but here + + + align:start position:0% +origin didn't get in the way but here +anywhere I try and move this curve it's + + align:start position:0% +anywhere I try and move this curve it's + + + align:start position:0% +anywhere I try and move this curve it's +going to have to it's going to have to + + align:start position:0% +going to have to it's going to have to + + + align:start position:0% +going to have to it's going to have to +hit the circle if I want to move it away + + align:start position:0% +hit the circle if I want to move it away + + + align:start position:0% +hit the circle if I want to move it away +so I can shrink it to a point in my + + align:start position:0% +so I can shrink it to a point in my + + + align:start position:0% +so I can shrink it to a point in my +region so this circle is kind of + + align:start position:0% +region so this circle is kind of + + + align:start position:0% +region so this circle is kind of +preventing me from from shrinking it + + align:start position:0% +preventing me from from shrinking it + + + align:start position:0% +preventing me from from shrinking it +down okay and then there are two more + + align:start position:0% +down okay and then there are two more + + + align:start position:0% +down okay and then there are two more +the fifth one is R2 minus a line + + align:start position:0% +the fifth one is R2 minus a line + + + align:start position:0% +the fifth one is R2 minus a line +segment so now we're in two- dimensional + + align:start position:0% + + + + align:start position:0% + +space okay and let me just pick a + + align:start position:0% +space okay and let me just pick a + + + align:start position:0% +space okay and let me just pick a +segment + + align:start position:0% +segment + + + align:start position:0% +segment +okay now this one is interesting oops + + align:start position:0% +okay now this one is interesting oops + + + align:start position:0% +okay now this one is interesting oops +again I did it I forgot to write whether + + align:start position:0% +again I did it I forgot to write whether + + + align:start position:0% +again I did it I forgot to write whether +it's Simply Connected or not let me come + + align:start position:0% +it's Simply Connected or not let me come + + + align:start position:0% +it's Simply Connected or not let me come +back over to four for posterity not + + align:start position:0% +back over to four for posterity not + + + align:start position:0% +back over to four for posterity not +Simply Connected okay sorry about that + + align:start position:0% +Simply Connected okay sorry about that + + + align:start position:0% +Simply Connected okay sorry about that +the fifth + + align:start position:0% +the fifth + + + align:start position:0% +the fifth +one because I'm in two Dimensions it's + + align:start position:0% +one because I'm in two Dimensions it's + + + align:start position:0% +one because I'm in two Dimensions it's +going to be not Simply Connected but if + + align:start position:0% +going to be not Simply Connected but if + + + align:start position:0% +going to be not Simply Connected but if +I add a third dimension it would become + + align:start position:0% +I add a third dimension it would become + + + align:start position:0% +I add a third dimension it would become +Simply Connected so I want to I want to + + align:start position:0% +Simply Connected so I want to I want to + + + align:start position:0% +Simply Connected so I want to I want to +explain why it's not Simply Connected + + align:start position:0% +explain why it's not Simply Connected + + + align:start position:0% +explain why it's not Simply Connected +here and then I want to show you why in + + align:start position:0% +here and then I want to show you why in + + + align:start position:0% +here and then I want to show you why in +a third dimension it it become Simply + + align:start position:0% +a third dimension it it become Simply + + + align:start position:0% +a third dimension it it become Simply +Connected okay the problem curves are + + align:start position:0% +Connected okay the problem curves are + + + align:start position:0% +Connected okay the problem curves are +the curves that do this that go around + + align:start position:0% +the curves that do this that go around + + + align:start position:0% +the curves that do this that go around +this line + + align:start position:0% +this line + + + align:start position:0% +this line +segment because notice if I want to try + + align:start position:0% +segment because notice if I want to try + + + align:start position:0% +segment because notice if I want to try +and contract this curve down to a point + + align:start position:0% +and contract this curve down to a point + + + align:start position:0% +and contract this curve down to a point +and I don't want to intersect that line + + align:start position:0% +and I don't want to intersect that line + + + align:start position:0% +and I don't want to intersect that line +segment in order to do it I actually + + align:start position:0% +segment in order to do it I actually + + + align:start position:0% +segment in order to do it I actually +have to move it away from the line + + align:start position:0% +have to move it away from the line + + + align:start position:0% +have to move it away from the line +segment I'd have to pass through the + + align:start position:0% +segment I'd have to pass through the + + + align:start position:0% +segment I'd have to pass through the +line segment at some point this curve + + align:start position:0% +line segment at some point this curve + + + align:start position:0% +line segment at some point this curve +would intersect that segment in order to + + align:start position:0% +would intersect that segment in order to + + + align:start position:0% +would intersect that segment in order to +be able to shrink it to a point in a + + align:start position:0% +be able to shrink it to a point in a + + + align:start position:0% +be able to shrink it to a point in a +region in the region I'm interested in + + align:start position:0% +region in the region I'm interested in + + + align:start position:0% +region in the region I'm interested in +so this + + align:start position:0% +so this + + + align:start position:0% +so this +this segment is sort of getting in the + + align:start position:0% +this segment is sort of getting in the + + + align:start position:0% +this segment is sort of getting in the +way we can think of it that way of + + align:start position:0% +way we can think of it that way of + + + align:start position:0% +way we can think of it that way of +allowing me to contract this down to a + + align:start position:0% +allowing me to contract this down to a + + + align:start position:0% +allowing me to contract this down to a +point actually also when we talked about + + align:start position:0% +point actually also when we talked about + + + align:start position:0% +point actually also when we talked about +simply connectedness in two Dimensions + + align:start position:0% +simply connectedness in two Dimensions + + + align:start position:0% +simply connectedness in two Dimensions +it was easier because we could say if we + + align:start position:0% +it was easier because we could say if we + + + align:start position:0% +it was easier because we could say if we +take any curve and we look at the the uh + + align:start position:0% +take any curve and we look at the the uh + + + align:start position:0% +take any curve and we look at the the uh +disc that's spanned by this curve so we + + align:start position:0% +disc that's spanned by this curve so we + + + align:start position:0% +disc that's spanned by this curve so we +say or it's the boundary of this curve + + align:start position:0% +say or it's the boundary of this curve + + + align:start position:0% +say or it's the boundary of this curve +we look at the region the curve + + align:start position:0% +we look at the region the curve + + + align:start position:0% +we look at the region the curve +encloses notice that this segment is in + + align:start position:0% +encloses notice that this segment is in + + + align:start position:0% +encloses notice that this segment is in +that region and there's no way of + + align:start position:0% +that region and there's no way of + + + align:start position:0% +that region and there's no way of +drawing this kind of curve without the + + align:start position:0% +drawing this kind of curve without the + + + align:start position:0% +drawing this kind of curve without the +segment being in that region + + align:start position:0% +segment being in that region + + + align:start position:0% +segment being in that region +and that's how we know it's not Simply + + align:start position:0% +and that's how we know it's not Simply + + + align:start position:0% +and that's how we know it's not Simply +Connected now in three dimensions what + + align:start position:0% +Connected now in three dimensions what + + + align:start position:0% +Connected now in three dimensions what +happens what if I took this exact same + + align:start position:0% +happens what if I took this exact same + + + align:start position:0% +happens what if I took this exact same +picture and I just made the z-axis come + + align:start position:0% +picture and I just made the z-axis come + + + align:start position:0% +picture and I just made the z-axis come +out from the board why is that suddenly + + align:start position:0% +out from the board why is that suddenly + + + align:start position:0% +out from the board why is that suddenly +Simply Connected whereas in the + + align:start position:0% +Simply Connected whereas in the + + + align:start position:0% +Simply Connected whereas in the +two-dimensional case it's not and the + + align:start position:0% +two-dimensional case it's not and the + + + align:start position:0% +two-dimensional case it's not and the +reason is because this same picture I + + align:start position:0% +reason is because this same picture I + + + align:start position:0% +reason is because this same picture I +could take this same curve and I could + + align:start position:0% +could take this same curve and I could + + + align:start position:0% +could take this same curve and I could +take this sort of shaded thing and I + + align:start position:0% +take this sort of shaded thing and I + + + align:start position:0% +take this sort of shaded thing and I +could push the Shaded thing out of the + + align:start position:0% +could push the Shaded thing out of the + + + align:start position:0% +could push the Shaded thing out of the +XY plane and so I'd still have the same + + align:start position:0% +XY plane and so I'd still have the same + + + align:start position:0% +XY plane and so I'd still have the same +boundary curve but I'd have the Shaded + + align:start position:0% +boundary curve but I'd have the Shaded + + + align:start position:0% +boundary curve but I'd have the Shaded +portion not hitting the segment and so I + + align:start position:0% +portion not hitting the segment and so I + + + align:start position:0% +portion not hitting the segment and so I +can find some surface with this boundary + + align:start position:0% +can find some surface with this boundary + + + align:start position:0% +can find some surface with this boundary +that doesn't have this segment in in the + + align:start position:0% +that doesn't have this segment in in the + + + align:start position:0% +that doesn't have this segment in in the +interior of the surface and that's + + align:start position:0% +interior of the surface and that's + + + align:start position:0% +interior of the surface and that's +another way of thinking about simply + + align:start position:0% +another way of thinking about simply + + + align:start position:0% +another way of thinking about simply +connectedness so in the two-dimensional + + align:start position:0% +connectedness so in the two-dimensional + + + align:start position:0% +connectedness so in the two-dimensional +case it is not Simply + + align:start position:0% +case it is not Simply + + + align:start position:0% +case it is not Simply +Connected but if I were to add a third + + align:start position:0% +Connected but if I were to add a third + + + align:start position:0% +Connected but if I were to add a third +dimension this region would become + + align:start position:0% +dimension this region would become + + + align:start position:0% +dimension this region would become +Simply Connected okay because I would + + align:start position:0% +Simply Connected okay because I would + + + align:start position:0% +Simply Connected okay because I would +have no problem with finding for any + + align:start position:0% +have no problem with finding for any + + + align:start position:0% +have no problem with finding for any +curve finding some surface that had that + + align:start position:0% +curve finding some surface that had that + + + align:start position:0% +curve finding some surface that had that +curve as a boundary that didn't + + align:start position:0% +curve as a boundary that didn't + + + align:start position:0% +curve as a boundary that didn't +intersect this segment so I could keep + + align:start position:0% +intersect this segment so I could keep + + + align:start position:0% +intersect this segment so I could keep +the the surface in the region I was + + align:start position:0% +the the surface in the region I was + + + align:start position:0% +the the surface in the region I was +interested in okay so that would tell me + + align:start position:0% +interested in okay so that would tell me + + + align:start position:0% +interested in okay so that would tell me +it was simply connected and then the + + align:start position:0% +it was simply connected and then the + + + align:start position:0% +it was simply connected and then the +last one is a solid Taurus okay and this + + align:start position:0% +last one is a solid Taurus okay and this + + + align:start position:0% +last one is a solid Taurus okay and this +one we might not have dealt with solid + + align:start position:0% +one we might not have dealt with solid + + + align:start position:0% +one we might not have dealt with solid +torai before but this is kind of an + + align:start position:0% +torai before but this is kind of an + + + align:start position:0% +torai before but this is kind of an +interesting problem okay so there are + + align:start position:0% +interesting problem okay so there are + + + align:start position:0% +interesting problem okay so there are +really fundamentally we we say in math + + align:start position:0% +really fundamentally we we say in math + + + align:start position:0% +really fundamentally we we say in math +it's sort of like there are two classes + + align:start position:0% +it's sort of like there are two classes + + + align:start position:0% +it's sort of like there are two classes +of curves that are interesting we won't + + align:start position:0% +of curves that are interesting we won't + + + align:start position:0% +of curves that are interesting we won't +get into a uh the exact terminology of + + align:start position:0% +get into a uh the exact terminology of + + + align:start position:0% +get into a uh the exact terminology of +what's happening but there are sort of + + align:start position:0% +what's happening but there are sort of + + + align:start position:0% +what's happening but there are sort of +two types of Curves on the Taurus one + + align:start position:0% +two types of Curves on the Taurus one + + + align:start position:0% +two types of Curves on the Taurus one +type of curve is the kind that goes + + align:start position:0% +type of curve is the kind that goes + + + align:start position:0% +type of curve is the kind that goes +around right here okay so it loops + + align:start position:0% +around right here okay so it loops + + + align:start position:0% +around right here okay so it loops +around the dut in that in that that + + align:start position:0% +around the dut in that in that that + + + align:start position:0% +around the dut in that in that that +direction but that type of curve is nice + + align:start position:0% +direction but that type of curve is nice + + + align:start position:0% +direction but that type of curve is nice +because notice that if I look at a + + align:start position:0% +because notice that if I look at a + + + align:start position:0% +because notice that if I look at a +surface the surface in there right it's + + align:start position:0% +surface the surface in there right it's + + + align:start position:0% +surface the surface in there right it's +it's all inside the solid Taurus so + + align:start position:0% +it's all inside the solid Taurus so + + + align:start position:0% +it's all inside the solid Taurus so +that's good so that seems like that's a + + align:start position:0% +that's good so that seems like that's a + + + align:start position:0% +that's good so that seems like that's a +curve that that promotes simply + + align:start position:0% +curve that that promotes simply + + + align:start position:0% +curve that that promotes simply +connectedness it seems to imply + + align:start position:0% +connectedness it seems to imply + + + align:start position:0% +connectedness it seems to imply +or it's not it's not telling us it's not + + align:start position:0% +or it's not it's not telling us it's not + + + align:start position:0% +or it's not it's not telling us it's not +Simply Connected we'll say that but + + align:start position:0% +Simply Connected we'll say that but + + + align:start position:0% +Simply Connected we'll say that but +there's another class of Curves on the + + align:start position:0% +there's another class of Curves on the + + + align:start position:0% +there's another class of Curves on the +Taurus and that's the class of curves + + align:start position:0% +Taurus and that's the class of curves + + + align:start position:0% +Taurus and that's the class of curves +that goes around this is a little harder + + align:start position:0% +that goes around this is a little harder + + + align:start position:0% +that goes around this is a little harder +to draw but say around the top but + + align:start position:0% +to draw but say around the top but + + + align:start position:0% +to draw but say around the top but +around the hole okay around the hole now + + align:start position:0% +around the hole okay around the hole now + + + align:start position:0% +around the hole okay around the hole now +any surface I have that I try + + align:start position:0% +any surface I have that I try + + + align:start position:0% +any surface I have that I try +to + + align:start position:0% +to + + + align:start position:0% +to +draw any surface that's going to have + + align:start position:0% +draw any surface that's going to have + + + align:start position:0% +draw any surface that's going to have +that curve as a boundary is at some + + align:start position:0% +that curve as a boundary is at some + + + align:start position:0% +that curve as a boundary is at some +point forced to leave the solid Taurus + + align:start position:0% +point forced to leave the solid Taurus + + + align:start position:0% +point forced to leave the solid Taurus +and the reason is really because of the + + align:start position:0% +and the reason is really because of the + + + align:start position:0% +and the reason is really because of the +hole in the middle right that's really + + align:start position:0% +hole in the middle right that's really + + + align:start position:0% +hole in the middle right that's really +the reason it happens okay and so you + + align:start position:0% +the reason it happens okay and so you + + + align:start position:0% +the reason it happens okay and so you +can sort of see the part right in here + + align:start position:0% +can sort of see the part right in here + + + align:start position:0% +can sort of see the part right in here +is on the surface but it's not in the + + align:start position:0% +is on the surface but it's not in the + + + align:start position:0% +is on the surface but it's not in the +it's not in the solid Taurus so because + + align:start position:0% +it's not in the solid Taurus so because + + + align:start position:0% +it's not in the solid Taurus so because +I have a curve that any surface I draw + + align:start position:0% +I have a curve that any surface I draw + + + align:start position:0% +I have a curve that any surface I draw +that has that curve as a boundary is + + align:start position:0% +that has that curve as a boundary is + + + align:start position:0% +that has that curve as a boundary is +forced to leave the solid T Taurus it's + + align:start position:0% +forced to leave the solid T Taurus it's + + + align:start position:0% +forced to leave the solid T Taurus it's +a non-s Simply Connected region so we + + align:start position:0% +a non-s Simply Connected region so we + + + align:start position:0% +a non-s Simply Connected region so we +say not Simply Connected + + align:start position:0% + + + + align:start position:0% + +okay so I just I'm going to go back + + align:start position:0% +okay so I just I'm going to go back + + + align:start position:0% +okay so I just I'm going to go back +through real quick and just remind us + + align:start position:0% +through real quick and just remind us + + + align:start position:0% +through real quick and just remind us +what was happening and maybe um maybe + + align:start position:0% +what was happening and maybe um maybe + + + align:start position:0% +what was happening and maybe um maybe +use the language I was using at the end + + align:start position:0% +use the language I was using at the end + + + align:start position:0% +use the language I was using at the end +to describe the first examples because + + align:start position:0% +to describe the first examples because + + + align:start position:0% +to describe the first examples because +that might help a little better so let's + + align:start position:0% +that might help a little better so let's + + + align:start position:0% +that might help a little better so let's +go back to the first examples okay in + + align:start position:0% +go back to the first examples okay in + + + align:start position:0% +go back to the first examples okay in +the R3 example again number one we know + + align:start position:0% +the R3 example again number one we know + + + align:start position:0% +the R3 example again number one we know +it's Simply Connected we're not going to + + align:start position:0% +it's Simply Connected we're not going to + + + align:start position:0% +it's Simply Connected we're not going to +worry about it okay but let me draw in + + align:start position:0% +worry about it okay but let me draw in + + + align:start position:0% +worry about it okay but let me draw in +number two Let Me point out maybe if I + + align:start position:0% +number two Let Me point out maybe if I + + + align:start position:0% +number two Let Me point out maybe if I +draw some shaded region this will help + + align:start position:0% +draw some shaded region this will help + + + align:start position:0% +draw some shaded region this will help +us understand it a little bit better + + align:start position:0% +us understand it a little bit better + + + align:start position:0% +us understand it a little bit better +number two establish is not simply + + align:start position:0% +number two establish is not simply + + + align:start position:0% +number two establish is not simply +connected and if you think about it if + + align:start position:0% +connected and if you think about it if + + + align:start position:0% +connected and if you think about it if +you have a curve that goes around the + + align:start position:0% +you have a curve that goes around the + + + align:start position:0% +you have a curve that goes around the +z-axis and you want to look at a surface + + align:start position:0% +z-axis and you want to look at a surface + + + align:start position:0% +z-axis and you want to look at a surface +that has that curve as its + + align:start position:0% +that has that curve as its + + + align:start position:0% +that has that curve as its +boundary this surface certainly + + align:start position:0% +boundary this surface certainly + + + align:start position:0% +boundary this surface certainly +intersects the z-axis the question is + + align:start position:0% +intersects the z-axis the question is + + + align:start position:0% +intersects the z-axis the question is +can I keep this curve the way it is and + + align:start position:0% +can I keep this curve the way it is and + + + align:start position:0% +can I keep this curve the way it is and +sort of pull the surface away and have + + align:start position:0% +sort of pull the surface away and have + + + align:start position:0% +sort of pull the surface away and have +it not intersect the z-axis and the + + align:start position:0% +it not intersect the z-axis and the + + + align:start position:0% +it not intersect the z-axis and the +answer is no any way I move this any way + + align:start position:0% +answer is no any way I move this any way + + + align:start position:0% +answer is no any way I move this any way +I move the inside of the curve basically + + align:start position:0% +I move the inside of the curve basically + + + align:start position:0% +I move the inside of the curve basically +what looks like a disc it's still going + + align:start position:0% +what looks like a disc it's still going + + + align:start position:0% +what looks like a disc it's still going +to intersect the z-axis somewhere right + + align:start position:0% +to intersect the z-axis somewhere right + + + align:start position:0% +to intersect the z-axis somewhere right +and so it's definitely not simply + + align:start position:0% +and so it's definitely not simply + + + align:start position:0% +and so it's definitely not simply +connected and the thing I was trying to + + align:start position:0% +connected and the thing I was trying to + + + align:start position:0% +connected and the thing I was trying to +point out in this second or the the + + align:start position:0% +point out in this second or the the + + + align:start position:0% +point out in this second or the the +number three that it is Simply Connected + + align:start position:0% +number three that it is Simply Connected + + + align:start position:0% +number three that it is Simply Connected +is you know if I if I shade the boundary + + align:start position:0% +is you know if I if I shade the boundary + + + align:start position:0% +is you know if I if I shade the boundary +of a curve sitting in the XY plane and + + align:start position:0% +of a curve sitting in the XY plane and + + + align:start position:0% +of a curve sitting in the XY plane and +then I take that sort of shaded disc and + + align:start position:0% +then I take that sort of shaded disc and + + + align:start position:0% +then I take that sort of shaded disc and +I push it up a little then it no longer + + align:start position:0% +I push it up a little then it no longer + + + align:start position:0% +I push it up a little then it no longer +hits the origin and I haven't and I + + align:start position:0% +hits the origin and I haven't and I + + + align:start position:0% +hits the origin and I haven't and I +haven't fundamentally changed my curve + + align:start position:0% +haven't fundamentally changed my curve + + + align:start position:0% +haven't fundamentally changed my curve +at all and so that that's a way of + + align:start position:0% +at all and so that that's a way of + + + align:start position:0% +at all and so that that's a way of +understanding that it is actually Simply + + align:start position:0% +understanding that it is actually Simply + + + align:start position:0% +understanding that it is actually Simply +Connected okay so there's sort of a + + align:start position:0% +Connected okay so there's sort of a + + + align:start position:0% +Connected okay so there's sort of a +couple ways to think about it and um and + + align:start position:0% +couple ways to think about it and um and + + + align:start position:0% +couple ways to think about it and um and +without being sort of incredibly + + align:start position:0% +without being sort of incredibly + + + align:start position:0% +without being sort of incredibly +mathematically precise these are sort of + + align:start position:0% +mathematically precise these are sort of + + + align:start position:0% +mathematically precise these are sort of +the best ways we have of thinking about + + align:start position:0% +the best ways we have of thinking about + + + align:start position:0% +the best ways we have of thinking about +understanding Simply Connected or not + + align:start position:0% +understanding Simply Connected or not + + + align:start position:0% +understanding Simply Connected or not +Simply Connected so again we had six + + align:start position:0% +Simply Connected so again we had six + + + align:start position:0% +Simply Connected so again we had six +examples removing the z-axis from R3 was + + align:start position:0% +examples removing the z-axis from R3 was + + + align:start position:0% +examples removing the z-axis from R3 was +not Simply Connected removing the origin + + align:start position:0% +not Simply Connected removing the origin + + + align:start position:0% +not Simply Connected removing the origin +from R3 was still Simply + + align:start position:0% +from R3 was still Simply + + + align:start position:0% +from R3 was still Simply +Connected removing a circle from R3 was + + align:start position:0% +Connected removing a circle from R3 was + + + align:start position:0% +Connected removing a circle from R3 was +not Simply Connected for the same region + + align:start position:0% +not Simply Connected for the same region + + + align:start position:0% +not Simply Connected for the same region +region reason as the z-axis problem CU + + align:start position:0% +region reason as the z-axis problem CU + + + align:start position:0% +region reason as the z-axis problem CU +here was my here was my disc and + + align:start position:0% +here was my here was my disc and + + + align:start position:0% +here was my here was my disc and +anywhere any way I try to sort of move + + align:start position:0% +anywhere any way I try to sort of move + + + align:start position:0% +anywhere any way I try to sort of move +the Shaded surface I can't I can't keep + + align:start position:0% +the Shaded surface I can't I can't keep + + + align:start position:0% +the Shaded surface I can't I can't keep +it from intersecting this + + align:start position:0% +it from intersecting this + + + align:start position:0% +it from intersecting this +circle and then number five was R2 minus + + align:start position:0% +circle and then number five was R2 minus + + + align:start position:0% +circle and then number five was R2 minus +a segment not Simply Connected but if I + + align:start position:0% +a segment not Simply Connected but if I + + + align:start position:0% +a segment not Simply Connected but if I +add another dimension it is Simply + + align:start position:0% +add another dimension it is Simply + + + align:start position:0% +add another dimension it is Simply +Connected for the same kind of reason + + align:start position:0% +Connected for the same kind of reason + + + align:start position:0% +Connected for the same kind of reason +that R3 minus the origin was and then + + align:start position:0% +that R3 minus the origin was and then + + + align:start position:0% +that R3 minus the origin was and then +number six was the solid Taurus which + + align:start position:0% +number six was the solid Taurus which + + + align:start position:0% +number six was the solid Taurus which +now it's kind of hard to see with the + + align:start position:0% +now it's kind of hard to see with the + + + align:start position:0% +now it's kind of hard to see with the +solid taus looks + + align:start position:0% +solid taus looks + + + align:start position:0% +solid taus looks +like but we said there's one one curve + + align:start position:0% +like but we said there's one one curve + + + align:start position:0% +like but we said there's one one curve +kind of curve that behaves fine but the + + align:start position:0% +kind of curve that behaves fine but the + + + align:start position:0% +kind of curve that behaves fine but the +curve that goes all the way around the + + align:start position:0% +curve that goes all the way around the + + + align:start position:0% +curve that goes all the way around the +hole shows it's in fact not Simply + + align:start position:0% +hole shows it's in fact not Simply + + + align:start position:0% +hole shows it's in fact not Simply +Connected so hopefully that was + + align:start position:0% +Connected so hopefully that was + + + align:start position:0% +Connected so hopefully that was +informative and that's where I'll + + align:start position:0% +informative and that's where I'll + + + align:start position:0% +informative and that's where I'll +stop \ No newline at end of file diff --git a/6b83DypBeYg.txt b/6b83DypBeYg.txt new file mode 100644 index 0000000000000000000000000000000000000000..5903044708d3e378464ba9a84b54f7753267bc51 --- /dev/null +++ b/6b83DypBeYg.txt @@ -0,0 +1,4113 @@ +The following +content is provided + +under a Creative +Commons license. + +Your support will help MIT +OpenCourseWare continue + +to offer high quality +educational resources for free. + +To make a donation or to +view additional materials + +from hundreds of +MIT courses, visit + +MIT at +OpenCourseWare@oce.mit.edu. + +PROFESSOR: OK, in that +case, let's get started. + +As usual, I like +to begin by giving + +a review of what we +talked about last time. + +This time on slides instead +of on the blackboard. + +We're talking mainly +about relativistic energy, + +or relativistic energy and +momentum, and pressure, + +sometimes. + +The key equation is probably +the most famous equation + +in physics, Einstein's +e equals m c squared. + +And I gave some +numerical examples. + +I actually looked up some +more numbers since then, + +when I was revising +the lecture notes. + +So these are slightly +more up to date. + +But it's still true that +if you could burn matter + +at the rate of one +kilogram per hour, + +you would have about +one and a half times + +the total power +output of the world. + +And that's apparently +still valid in 2011. + +I only had 2008 figures, +actually, at the lecture + +last time. + +And if you imagine the +15-gallon tank of gasoline, + +and you could figure out how +much that-- what it's mass is, + +and convert that to +energy, it turns out + +that a 15-gallon +tank of gasoline + +could power the world for about +two and half days, if you could + +convert all of it into energy. + +The catch, of course, is +that we can't convert matter + +into energy. + +We can't get around the problem +that, at least at the energies + +that we deal with, +baryon number. + +And that number of protons +and neutrons is conserved, + +so we can't make protons +and neutrons disappear. + +And that means that we're +limited in what we can do. + +In particular, one of the most +efficient things we can do + +is fission uranium 235. + +But when uranium 235 undergoes +fission, less than 1/10 + +of 1% of the mass is +actually converted + +into energy, which is why we +can't actually avail ourselves + +of these fantastic +numbers that would apply, + +if we could literally just +convert matter into energy. + +We went on to talk about +the relativistic definitions + +of energy and momentum, +and how they come together + +to form a Lorentz four vector, +and the underlying theme here + +is that we consider ourselves +users of special relativity. + +Most of you I know have taken +special relativity courses, + +and for those of you who +have, this is a review. + +For those you who have not, +and there are some of those + +also, no need to panic. + +I intend to tell you +every fact that you + +need to know about +special relativity. + +I won't tell you how +to derive them all, + +but I'll tell you all you'll +need to know for this class. + +So in particular, it's +useful for this class + +to recognize that energy and +momentum can be put together + +into a four vector, where +the zeroth component + +is the energy divided +by the speed of light. + +And the three spatial components +are just the three components + +of the spatial +momentum, although they + +have to be defined +relativistically. + +The relativistic +definition of momentum, + +at least how it +relates to velocity, + +is that it's equal to +gamma times the rest + +mass times the velocity, where +gamma is the famous factor + +that we've been +seeing all along when + +we've talked about relativity. + +The Lorentz +contraction factor, one + +over the square root of 1 +minus v squared over c squared. + +The energy of a particle, +relativistically, + +is the same gamma, times m +0 times c squared, and it + +can also be written as +the square root of m 0 + +c squared squared, plus +the momentum squared, + +times c squared. + +Since the momentum +forms a four vector, + +its Lorentz and variant square +should be Lorentz and variant, + +and that means that +the momentum squared + +minus p 0 squared should be the +same in all inertial reference + +frames. + +And that's just +equal when you put + +in what p 0 means, +the momentum squared + +minus the energy squared, +divided by c 0 squared. + +And to know what value it's +equal to in all frames, + +it's efficient to know what +it's equal to in one frame. + +And the one frame +where we do know + +what it's equal to is the +rest frame of a particle. + +So in the rest frame, +the momentum vanishes, + +and the energy is +just m 0 c squared. + +So in the rest frame, +we can evaluate this, + +and we get minus m +0 c squared squared. + +And that means that has to +be the value in every frame. + +And this in fact is +the easy way to derive + +the relationship between +energy and momentum. + +If we go back, the +equation we had + +relating energy and momentum is +really exactly that equation, + +rearranged. + +Just to give an example of how +this works, when we actually + +have energy exchanges, +I pointed out + +that we could talk about the +energy of a hydrogen atom. + +And because energy and +mass are equivalent, + +the hydrogen atom clearly +has a little bit less energy + +than an isolated proton, +plus an isolated electron. + +Because when you +bring them together + +there's a binding energy, +and that binding energy + +is called delta e, and has +a value of 13.6 electron + +volts for the ground +state of hydrogen. + +So that tells us the +mass of an hydrogen atom + +is not the sum of +the two masses, + +but rather has this +correction factor, + +because we've taken out a little +bit of energy for the binding. + +And that means we've taken +out a little bit of mass. + +OK, then we talked about the +mass density of radiation + +and how-- building up to how +that will affect the universe. + +And we said that the +mass density of radiation + +is just the energy density +divided by c squared. + +And that can be taken, really, +as a definition of what + +we call relativistic +mass, and hence + +relativistic mass density. + +But the important point is +that this mass density actually + +does gravitate the +same as any other mass + +density of the same value. + +It really does create +gravity in the same way. + +Now I mentioned that things are +much more complicated if you + +want to talk about the +gravitational field produced + +by a single moving particle. + +That's asymmetric, the +velocity of the particle + +shows up in the equations that +describe the metric surrounding + +a single moving particle. + +But if you have a gas +of particles moving + +at high velocities, where +the velocities nonetheless + +average to zero, which +tends to happen, in a gas + +at least in the rest +frame of the gas. + +Then that gas will produce +gravitational fields, + +just like a static mass density. + +Where the mass density is this +relativistic energy divided + +by c squared, the relativistic +definition of the mass density. + +It's also useful to know +that the photon-- if we want + +to describe it as a particle, +is a particle of zero rest mass. + +Which means that it +can never be at rest, + +it always moves at +the speed of light. + +And it also means that its +energy can be arbitrarily + +small, because the energy +is proportional of momentum, + +and the momentum of a photon +can be as small as you like. + +For giving frequency, of +course, the energy of a photon + +is fixed. + +It's h times nu but +if you're allowed + +to vary the frequency, +which you can do if you just + +look at it in +different frames, you + +can make the energy +as small as you like. + +And the famous equation +then, p squared minus e + +squared c squared, which +would have on the right, + +minus m 0 squared +c to the 4th m 0 + +squared c squared, excuse me-- +has zero on the right hand + +side, because m 0 +is 0 And that means + +that for photons, the energy is +just the speed of light times + +the momentum. + +And that's a famous +relationship that photons obey. + +Now, thinking about +how this gas of photons + +will behave in the universe, +we realized immediately + +that it does not +behave the same way + +as a mass density of ordinary +non-relativistic particles. + +Which is what we have +been dealing with to date. + +The important difference +is that in both cases, + +the number density falls +off like 1 over a cubed, + +as the universe expands, +these particles are not + +created and destroyed +in significant numbers, + +they just persevere. + +So the number density of either +non-relativistic particles, + +or photons, just falls off +like one over the volume, + +as the volume increases and +the number density dilutes. + +But what makes photons +different from non-relativistic + +particles, is that a +non-relativistic particle + +will maintain the +energy of that particle + +as the universe +expands, but photons + +will redshift as the +universe expands. + +So each photon will +itself lose energy. + +And it loses energy proportional +to one over the scale factor. + +And that's just because the +frequency shift proportionally + +to the scale factor. + +And that means that +the energy per photon + +shifts, because +quantum mechanically + +we know that the +energy of a photon + +is proportional +to its frequency. + +So if the frequency +redshifts so must the energy. + +In exactly the same +way, 1 over a f t. + +Yes, question? + +AUDIENCE: You said +previously that neutrinos + +behave like radiation +in the sense + +that theta energy +falls is 1 over a. + +What is it about them +that makes this happen? + +Because there are also particles +with standard kinetic energy, + +right? + +PROFESSOR: OK, the question, +in case you didn't hear it, + +is why-- how did +neutrinos fit in here? + +I've made the claim that +neutrinos act like radiation + +in the early universe, but +neutrinos have a non-zero mass, + +so they should obey the +standard formulas for particles + +with nonzero masses. + +The answer to that +is-- there is, + +I think, a simple answer, +which is that as long + +as the energy is large +compared to the mass, + +particles with masses will still +act like massless particles. + +It doesn't really matter +if the mass is zero or not, + +the key thing, really, +is this equation. + +So if the term on +the right hand side + +is small compared to either +of the two on the left, + +it's not much different +from being zero. + +And that's what +happens for neutrinos + +in the early universe. + +And we'll see soon that if +you go to early enough times, + +it's true even for +electron-positron pairs. + +They will also act +like radiation. + +Any particle will +act like radiation + +as long as the energy is large +compared to the rest energy. + +So getting back +to the discussion + +of the early universe, if +the energy of each photon + +falls off like one +over the scale factor, + +and the number density falls off +like one over the scale factor + +cubed, it means that +the energy density, + +and hence, the mass +density of radiation + +will fall off like one +over a to the fourth, + +in contrast to the one over +a cubed, that we found when + +we were talking about +non-relativistic matter. + +And that, of course, is +going to make a difference. + +Because those issues play a +key role in our discussions + +about how the universe evolved. + +An important feature, +which we see immediately, + +is that if we extrapolate +backwards in time, + +since the radiation mass density +is falling off like one over a + +to the fourth, and the +matter density is falling off + +like one over a cubed, it means +that as you go back in time, + +the radiation becomes +more and more important + +relative to the matter, by +factor of the scale factor. + +So if we go back far +enough, we will even + +find a time when the +mass density in radiation + +equaled the mass density +in non-relativistic matter. + +And we calculated about +when that would be. + +We said that the energy +density in radiation today + +is given by this number, 7 +times 10 to the minus 14, + +joules per meter cubed. + +And I just gave you this +number, I didn't derive it yet. + +We will derive it, +probably later today. + +But for now, we're +just accepting it. + +And that implies +we can calculate + +from that the ratio +of the mass densities + +in radiation and +ordinary matter. + +Here, we use the fact +that ordinary matter + +can be described +by having an omega + +ratio to the critical +density of about 0.3. + +And we know how to calculate +the critical density, + +and that allowed us to calculate +the density of ordinary matter. + +And then this ratio turned +out to be 3.1 times 10 + +to the minus four. + +So radiation in +today's universe is + +almost negligible +in its contribution + +to the overall energy +balance, compared + +to non-relativistic matter. + +But if you +extrapolate backwards, + +we know that this ratio will +vary as one over the scale + +factor. + +And we could figure +out what constants + +to put this equation by +putting in the right constant, + +so that this equation gives +us the right value today. + +Where the right value today is +3.1 times 10 to the minus four. + +And notice that +this works, if we + +let t be equal to t sub +zero, this factors one + +and we get 3.1 times +10 to the minus four. + +So these two factors +together they + +have t zero and the 3.1 +times 10 to the minus four, + +are just the right +factors to put in + +to give us the right +constant of proportionality + +in that equation. + +Having this +equation, we can then + +ask, how far back do we +have to go, how much we have + +to change t, for +the ratio to be one? + +And that's a +straightforward calculation. + +And the ratio of the a is +then just one over 3.1 times + +10 to the minus four, or 3,200. + +So if we talk about it in +terms of a redshift, which + +is how astronomers always talk +about distances, or times, + +we're talking about going +back to a redshift of 3,200. + +We can figure out what time, +then, corresponds to also, + +if we know how a f +t depends on time. + +And we do, approximately. + +For this calculation, +I assume for now, we + +could do better +later, and we will-- + +but I assume for now +that we could just + +treat the period between matter +radiation equality, so-called t + +x and now as being +entirely described + +by a matter-dominated universe. + +That's only a crude +approximation, + +but it will get us the +right order of magnitude. + +And we'll learn how to do +better later in the course. + +So if we assume that, then t x +is just this number to the 3/2 + +power, cancelling the 2/3, times +the age of universe, t naught. + +And that turned out to +be about 75,000 years. + +So somewhere in the range of +100,000 years, 50,000 years, + +is the time in the history of +the universe when radiation + +ceased to be more +important than matter. + +And for earlier times than +that, the radiation dominated. + +And that's what we refer to as +the radiation dominated era. + +Any questions? + +OK, now I think we get +on to what is really + +the important subject that +we want to understand, + +and most of this you did +yourself on the homework. + +But I'll summarize +the argument here. + +We want to understand +what this tells us + +about the Friedmann Equations. + +And first, we'd +like to understand + +what it says about pressure. + +Because it turns +out that pressure + +is the crucial +issue in determining + +how fast row falls +off as a expands. + +So if row is proportional +to one over a cubed, + +we can just differentiate +that, putting + +in a constant proportionality +temporarily, just + +to keep track of +what we're doing. + +Since we know how to +differentiate qualities + +and we're less familiar +with how to differentiate + +proportionalities. + +But what we find immediately, +is that row dot is then minus 3, + +where that 3 is that 3, +times a dot over a times row. + +On the other hand, if +row of t falls like one + +over a to the fourth, +row dot is minus 4 times + +a dot over a times row, +just by differentiation. + +So we get different +expressions from row dot, + +between radiation and matter. + +And we want to explore +the consequences + +of that difference. + +It's related to the +pressure of the gas, + +because we can relate +the pressure to row dot. + +Because we know that +as a gas expands, + +it loses energy, which is +just equal in amount to pdV. + +And we illustrated this by +a piston thought experiment, + +but it's true in general. + +So we can apply this famous +formula, dU equals minus pdV, + +to a patch of the +expanding universe. + +And by a patch I mean some fixed +region and coordinate space. + +So the total energy in that +region of coordinate space + +will be the physical +volume, which + +will be a cubed times +the coordinate volume. + +Which is going to cancel out +of this equation on both sides. + +So it's a cubed times +the coordinate volume + +times the energy density, +which is row c squared. + +The rate of change +of that is Du. + +And then on the +right hand side, we + +have minus p minus +b times dV, which + +is the rate of change +of a cubed, again + +times the coordinate volume +that we're talking about. + +But that will cancel out on +the two sides of the equation. + +So this is really +just a description + +for the universe of the dU +equals minus pdV equation. + +And this can just be rearranged, +expanding the time derivatives, + +to give us row dot, and +we get minus 3 a dot + +over a, times row +plus p over c squared. + +So this tells us how to relate +row dot to the pressure. + +And it tells us that the +formula that we started + +with a long time ago, which +just said that row fell off + +like 1 over a cubed, was +synonymous with saying + +the pressure is zero, for a gas +of non-relativistic particles, + +the pressure is negligible. + +But for radiation, +clearly if we're + +going to get a four +instead of a three, + +the pressure will +be non-negligible. + +And in fact, it implies +that the pressure + +is exactly equal to +one third of the energy + +density for a gas of radiation. + +OK, knowing that, we can now +look back at the Friedmann + +equations and ask, +how do they stand up? + +Are they still consistent, or +do we have to modify something? + +And this is really +the crucial point. + +What we know are +these three equations, + +which are the two +Friedmann equations + +and the equation for row dot. + +And we could see immediately +that those equations are not + +independent of each other. + +The easiest thing +to see is that if we + +start with the top equation, +we could differentiate it. + +And since the top +equation has a dot in it, + +when we differentiate, we'll get +an equation for a double dot. + +But the equation will +also involve row dot, + +if we take the time derivative +of that top equation. + +But if we know +what row dot is, we + +could put that +in, and in the end + +we'll get an equation for +a double dot by itself. + +And it will in fact +agree with the equation + +on the middle line. + +Again, things would +be inconsistent. + +Things are consistent, we +didn't make any mistakes. + +If we derive the +equation for a double dot + +by using the first and +third of those equations, + +then we'll get the second +of those equations. + +But the catch is +that now we want + +to modify the third +of those equations, + +the equations for row dot. + +And then the Friedmann +equations as we've + +written them will not +be consistent anymore. + +Because we'll have a different +equation for row dot, + +we'll get a different +equation for a double dot. + +So we have to decide what gives. + +What can we change to make +everything consistent? + +And here, the rigorous +way of proceeding + +is to look at general +relativity and see what it says, + +and the answer we're +going to write down + +is exactly what general +relativity says. + +But we can motivate +the answer in, I think, + +a pretty sensible +way, by noticing + +that as the universe +expands, we'd + +expect the energy density +to vary continuously, + +because energies are conserved. + +And we also expect a dot +to vary continuously, + +because basically, the +mechanics of the universe + +are like ton's laws. + +And velocities don't +change discontinuously. + +You can apply a +force, and that causes + +velocities to have +a rate of change. + +But velocities don't +change instantaneously, + +unless you somehow +apply an infinite force. + +And the same thing will +be true with the universe. + +On the other hand, accelerations +can change instantaneously. + +You could change the force +acting on a particle, + +in principle, as +fast as you want, + +and the acceleration +of the particle + +will change at that same rate. + +So if we look at +these equations, + +we would expect that the first +equation and the third equation + +would not be allowed to +involve the pressure. + +Because the pressure basically +is a measure of a force. + +Pressures can change +instantaneously. + +So what you need to +do, if we're going + +to make these equations +consistent in the presence + +of pressure-- which changes +the row dot equation, + +the only equation we can +change is the second one. + +And then we can +ask ourselves, what + +do we have to change it to make +the three equations consistent? + +And this is what you +looked at on your homework. + +And the answer is that +the a double dot equation + +has to be modified +to give the equation + +at the bottom of +the screen here. + +And this is the correct form +of the a double dot equation + +in cosmology. + +And this is what we'll be +using for the rest of the term, + +this is exactly what you would +get from general relativity. + +As long as we're talking +about homogeneous + +and isotropic universes, +this formula as exact + +as far as we know. + +OK, any questions about that? + +Yes. + +AUDIENCE: Why when we derive +that equation do we use-- + +PROFESSOR: This equation? + +AUDIENCE: Or the one above that. + +PROFESSOR: Yeah. + +AUDIENCE: We use dU +equals minus pdV? + +I mean, I agree with +that, but couldn't we + +use a more complete version? + +Like, the complete +version of the first law + +of thermodynamics, that +dU equals TDS minus pdV. + +PROFESSOR: OK, yeah. + +The question was when we wrote +down dU equals minus pdV, + +why did we not include +a plus TDS term here, + +which could also be relevant. + +The answer is that +for the applications + +we're interested in-- +you're quite right, + +it could be important, +but for the applications + +that we're interested in, +which is the expanding + +gas in the universe, the +expanding gas in the universe + +will be making use of this fact. + +It really does expand +adiabatically, that is, + +there's nothing +putting heat in or out, + +and everything is remaining very +close to thermal equilibrium, + +which means that entropy does +not spontaneously change. + +So the TDS term we will be +assuming is very, very small, + +and that's accurate. + +And you're right, if +that were not the case, + +there would be further +complications in terms + +of figuring out what row dot is. + +Let me point out here that +this equation actually + +does contain a somewhat +startling perhaps fact + +about gravity it says +that in the context + +of general relativity. + +And that's really the +context that we're in, + +even though we haven't learned +a lot of general relativity. + +But it says that in the +context of general relativity, + +pressures, as well +as mass densities, + +contribute to the +gravitational field. + +A double dot is +basically a measure + +of how fast gravity is +slowing down the universe. + +And this says that +there's a pressure. + +It can also help to +slow down the universe. + +Meaning that pressure itself can +create a gravitational field. + +In the early universe, +where we go back + +to this radiation +dominated period, + +we know that the pressure is +one third of the energy density. + +That says that +this pressure term + +is the same size exactly +as the mass density term. + +So in the radiation +dominated phase, + +the pressure is just +as important in effect + +for slowing down the universe +as is the mass density. + +In today's universe +it's negligible. + +Well, we'll come back that. + +The dark energy has a +non-trivial pressure, + +but the pressure of ordinary +matter in today's universe + +is negligible. + +The other important +fact about this equation + +is that energy densities, +so far as we know, + +are always positive. + +We don't know for sure what +the ultimate laws of physics + +are, but for all the laws +of physics that we know, + +energy densities are positive. + +On the other hand, +pressures actually + +can be negative for +some kinds of material. + +And we'll talk a little +bit more about how + +to get a negative +pressure later. + +But this formula tells us +that positive pressures + +act the same way as +positive mass densities, + +creating an attractive +gravitational field which + +slows down the expansion +of the universe. + +But if there could be a material +with a negative pressure, + +this same equation, which +would presumably still hold, + +and believe it +does, would tell us + +that that negative +pressure would actually + +cause the universe to +accelerate, because + +of its gravitational effects. + +Now, we're not talking +about the mechanical effects + +of the pressure. + +Mechanical effects +of pressure only + +show up when there are +pressure gradients, when + +the pressure is uneven. + +So the very large air +pressure in this room, + +which really is quite +large, we don't feel all, + +because it's acting +equally in all directions. + +Uniform pressures do +not produce forces. + +So the mechanical effects of the +pressure in the early universe, + +which we're assuming is +completely homogeneous, + +is zilch. + +There is no mechanical effect. + +But what we're seeing +in this equation + +is a gravitational effect +caused by the pressure. + +And it's obviously +gravitational, + +business the effect is +proportional to Newton's + +capital G, a +constant determining + +the strength of gravity. + +So the equation is telling +us that a positive pressure + +creates a gravitational +attraction, which + +would cause the universe to +slow down in its expansion. + +But a negative +pressure would produce + +a gravitational repulsion, +which would cause universe + +to speed up. + +And we now know that, +today-- in fact, + +for the last five billion +years or so-- our universe + +itself is actually accelerating +under the influence + +of something. + +And the only +explanation we have is + +that the something that's +causing the universe + +to accelerate is the +repulsive gravity caused + +by some kind of a negative +pressure material. + +And that negative +pressure material + +is what we call the dark energy. + +And we'll talk a little +more later about what it is. + +It's very likely +just vacuum energy. + +But we'll come back to +that later in the course. + +Yes? + +AUDIENCE: When we looked at +the toy example of the piston + +in the cavity, the +pressure of the gas + +was pushing outwards against +the wall of the container. + +But we can't have that view +of the universe, really, + +because there's no +exteriors in the universe. + +PROFESSOR: There's +no walls, right. + +AUDIENCE: So how should we view +pressure in the sense that-- + +PROFESSOR: OK. + +Yeah. + +OK, the question is, in our toy +problem involving the piston, + +we had walls for the +pressure to push against. + +And that was where +the energy went. + +It went into pushing the walls. + +When we're talking about the +universe, there are no walls. + +How does that analogy work? + +What plays the +role of the walls? + +And the answer, I think, is +that the role of the walls, when + +we're talking about the +universe, first of all, you + +can ignore it if you just +took in a small region. + +You could still just +say, the small region + +is pushing out on the +regions around it. + +And I think that's enough +to make the logic clear. + +But it still leaves open +the question of, ultimately, + +where does this energy go? + +So saying it goes +from here to there + +doesn't help you +unless you know where + +it goes after it goes +from and there and there. + +So you might want to ask +the question more generally, + +where does the energy +ultimately end up? + +And then I think the +answer is that it ends up + +in gravitational +potential energy. + +You could certainly build +a toy model, where you just + +have a gas in a finite region, +self-contained under gravity. + +And then you'd have to make +up some kind of a mechanism + +to cause it to expand. + +But when you cause +it to expand, you'll + +be pulling particles +apart, which + +are attracting each +other gravitationally. + +And that means +you'll be increasing + +the gravitational +potential energy + +as you pull the gas apart. + +So I think, ultimately, the +answer is the energy imbalance + +that we seem to be +seeing here is taken up + +by the gravitational field +so that, all in all, energy + +still conserved. + +Any other questions? + +OK, in that case, let us +continue on the blackboard. + +OK, first thing I +want to look at it + +is just the behavior of a +radiation-dominated flat + +universe. + +So a flat universe +is going to obey + +H squared equals +8 pi over 3 G rho, + +and then the potential minus +kc squared over a squared. + +Hard to write dotted +lines on the blackboard. + +But this potential term is +not there, because k equals 0. + +We're talking about +the flat case. + +So for a flat case, we could +just express H in terms of rho. + +And we know how rho +behaves for radiation. + +Rho falls off as +1/a to the fourth. + +So H squared is proportional +to 1/a to the fourth. + +That means that H itself is +proportional to 1/a squared. + +So we can do that. + +a-dot over a is equal to +some constant over a squared, + +a-dot over a being H. And now +we can multiply both sides + +by a, of course. + +And we get a-dot is equal +to a constant over a. + +And this we can integrate. + +The way to integrate is +to put all the a's on one + +side and all of the +dt's on the other side. + +So we get ada, +writing this as da/dt. + +So ada is equal to +the constant times dt. + +And then, as we've +done before, when + +we're talking about matter, +it's the same calculation there. + +I just did different +power of a appears + +so we'd know how to do it. + +Integrating, we get 1/2a squared +is equal to the constant times + +t, and then plus a new constant +of integration, constant prime. + +Now we make the same argument +as we've made in the past. + +We have not yet +said anything that + +determines how our clocks +are going to be set. + +So we can choose to set our +clocks in the standard way, + +which is to set our +clocks so that t equals + +0 corresponds to the moment +where a is equal to 0. + +And if a is going to be equal +to 0 when t is equal to 0, + +it means constant prime +is going to be equal to 0. + +So by choosing the +value of constant prime, + +we really are just +determining how + +we're going to set +our clocks, how + +we're going to +choose the 0 of time. + +And we'll do that by setting +constant prime equal to 0. + +And then we get +the famous formula + +for a radiation-dominated +universe, a of t + +is just proportional to +the square root of t, + +or t to the 1/2 power. + +And this is for a +radiation-dominated flat + +universe, replacing +the t to the 2/3 + +that we have for the +matter-dominated flat universe. + +Once we know that +a is proportional + +to the square root of t-- +and for the flat universe, + +the constant proportionality +mean nothing, by the way. + +It's not that we haven't +been smart enough + +to figure out what it is. + +It really has no +meaning whatever. + +You could set it equal +to whatever you want, + +and it just determines +your definition + +of the notch, your +definition of how you're + +going to measure the +comoving coordinate system. + +Once we know this, we should +know pretty much everything. + +So in particular, +we can calculate + +h, which a-dot over a. + +And the constant +proportionality drops + +when we compute a-dot over a. + +As we expect, it has no meaning. + +So it should not appear in +the equation for anything + +that does have physical meaning. + +So H is just 1/2t, +the 1/2 here coming + +from differentiating +the t the 1/2 power. + +We can also compute +the horizon distance. + +So the physical horizon +distance, l sub p horizon, + +where p stands for physical, +is equal to the scale factor + +times the coordinate +horizon distance. + +And the coordinate +horizon distance + +is just the total +coordinate distance + +that light could travel from +the beginning of the universe. + +And we know the coordinate +velocity of light + +is c divided by a. + +So we just integrate that to get +the total coordinate distance. + +So it's the integral +from 0 to t of c + +over a of t prime dt prime. + +And since a of t is +just t to the 1/2, + +this is a trivial +integral to do. + +And the answer is +2 times c times t. + +So in a radiation-dominated +universe, + +the horizon's distance +is twice c times t. + +For a static universe, +the horizon distance + +would just be c times t. + +It would just be the distance +light can travel in time t, + +but more complicated in +an expanding universe. + +For the matter-dominated +case, we + +discovered that the +horizon distance was 3ct, + +if you remember. + +For the radiation-dominated +case, it's 2ct. + +And finally, an +important equation + +is that, going back to +here, where we started, + +this equation relates H to rho. + +We found out that, +merely by knowing + +the universe is +radiation-dominated, + +without even caring about +what kind of radiation + +it is, how much neutrinos, +how much photons, whatever-- + +doesn't matter-- merely +by knowing the universe + +is radiation-dominated, we were +able to tell that H is 1/2t. + +And if we know what H +is, that formula tells us + +we also know what rho is. + +So without even knowing +what kind of radiation + +is contributing, we know that, +for a radiation-dominated + +universe, rho is just +equal to 3 over 32 + +pi Newton's constant G times +time, little t, squared. + +It's rather amazing that we +can write down that formula + +without even knowing what kind +of radiation is contributing. + +But as long as that +radiation falls + +off as 1 over the scale +factor to the fourth, + +and as long as we know +the universe is flat, + +then we know what that +energy density has to be. + +This is crucial +here, by the way. + +The energy could be +anything if we did not + +assume that the +universe was flat. + +OK, any questions about this? + +Yes? + +AUDIENCE: If we assumed +that it was almost flat, + +would we be able to +have any bounds on it? + +PROFESSOR: OK, question +is, if we assumed + +that it was almost +flat, would we + +be able to have +any bounds on it? + +The answer is, yeah, if +you were quantitative + +about what you meant +by "almost flat," + +you could know how almost true +that formula would have to be. + +OK, if there are +no other questions, + +I want to switch +gears slightly now + +and go back to talk about some +of the basic underlying physics + +that we are going to need, +and in particular, the physics + +of black-body radiation. + +So this is really just a little +chapter of a stat mech course + +that we're inserting +here, because we need it. + +And because it comes +from another course, + +we're not going try to +do it in complete detail. + +But I'll try to write down +formulas that make sense. + +And that will give us what +we need to know to proceed. + +So that will be the goal. + +So what is black-body radiation? + +The physical phenomenon +is that, if one imagines + +a box with a cavity +in it-- that's + +supposed to be a box +with a cavity in it, + +in case you can't recognize the +picture-- if the box is held + +at some uniform temperature +t-- t is temperature-- + +then is claimed and +verified experimentally + +that the cavity will fill up +with radiation-- in this case, + +we're really just talking about +electromagnetic radiation-- + +the calving will fill up with +electromagnetic radiation + +whose characteristics +would be determined solely + +by that temperature +t and will therefore + +be totally independent of the +material that makes up the box. + +Roughly speaking, +I think the way + +to think about it is to say +that the box will fill up + +with radiation at temperature t. + +And saying that the +radiation has temperature t + +is enough to completely +describe the radiation. + +It doesn't matter +what kind of a box + +that radiation is sitting in. + +So the box will fill with +radiation at temperature t. + +And that radiation is +called black-body radiation. + +Like many things in physics, +it has a variety of names, + +just to confuse us all. + +So it's also called +cavity radiation, + +which makes a lot +of sense, given + +the description we just gave. + +And it's also sometimes called +just thermal equilibrium + +radiation. + +This is radiation +at temperature t. + +I haven't really justified +the word "black-body" + +radiation yet, so let me +try to do that quickly. + +The reason why it can be called +black-body radiation-- and this + +will be important for +some things in cosmology; + +I'm not sure if it will +be important to us or not, + +but certainly important to +know-- the reason why it's + +called black-body radiation is +because we imagine inserting + +into this cavity a black +body, in the literal sense. + +What is the literal +sense of a black body? + +It's a body which is +black in the sense + +that all radiation that +hits it is absorbed. + +Now, this black body +is still going to glow. + +If you heat a piece +of iron or something + +to very high temperatures, +you see it glow. + +That glow is not reflection. + +That glow is emission +by the hot atoms + +in the piece of +iron or whatever. + +Emission is different +from reflection. + +When we say it +absorbs everything, + +we mean it does not +reflect anything. + +But it will still admit +by thermal de-excitation. + +The crucial distinction between +reflection and thermal emission + +is that reflection +is instantaneous. + +When a light beam comes +in, if it's reflected, + +it just goes back +out instantaneously. + +Emission, thermal emission, +is a slower process. + +Atoms get excited, +and eventually, they + +de-excite and emit radiation. + +So it takes time. + +And that's the distinction. + +We're going to assume that +this body is black in the sense + +that there's no reflection. + +OK, now we're going to +make use of the fact + +that we know that thermal +equilibrium works. + +That is, if you let any +isolated system sit long enough, + +it will approach a unique +state of thermal equilibrium + +determined by its constituents, +which you've put in + +to begin with, but otherwise +independent of how exactly + +you arrange those constituents. + +So if we put in, for +example, a cold black body, + +it will start to get +harder, warming up + +to the same temperature +as everything else. + +If we put in an +extra hot black body, + +it would emit energy +and start to cool down + +to the temperature +of everything else. + +But eventually, +this black body will + +be at the same temperature +as everything else. + +And we're going to be assuming +here that the box itself + +is being held at some +fixed temperature t. + +So wherever energy +exchange occurs + +because of this +black body, it will + +be absorbed by +whatever is holding + +the outer box at the +fixed temperature. + +So in the end, if +we wait long enough, + +this black body is going to +acquire the same temperature + +as everything else and +hold that temperature. + +Now, if it's holding +that temperature, + +it means that the energy input +to the box, to the black body, + +will have to be the +same as the energy + +output of the black body. + +Now, the black body is going +to be absorbing radiation, + +because we have +radiation here, and we + +said that any radiation +that hits it is absorbed. + +That was the +definition of "black." + +So it's clearly +absorbing energy. + +If it's not going +to be heating up-- + +and we know that it's +not, because it's + +in thermal equilibrium; the +temperature will remain fixed-- + +in order for it +to not heat up, it + +has to radiate energy, as well. + +And the energy it radiates +has to be exactly the same + +as the energy it's +absorbing once it + +reaches thermal equilibrium. + +So in equilibrium, the black +body, BB, radiates at same rate + +that it absorbs energy. + +This radiation process +is this slow process + +of thermal emission. + +There are atoms inside this +black body that are excited. + +Those atoms will +de-excite over time, + +releasing photons +that will go off. + +And the important thing +about that slow mechanism + +is that, if we imagine +taking this black body out + +of its cavity, but not waiting +long enough for its temperature + +to change-- so we'll +assume its temperature + +is still the same, t. + +So this is a picture of the same +black body at temperature t, + +but now outside the cavity. + +Its radiation rate is not +going to change when we take it + +outside the cavity, because the +radiation was caused by things + +happening inside the black body, +which are not changed when we + +put it in or out of the cavity. + +So it will continue to radiate +at exactly the same rate + +that it was radiating +when it was in the cavity. + +And that means it's +going to radiate + +at exactly the same +rate as the energy + +that it would have +absorbed if it were bathed + +by this black-body radiation. + +So essentially, it means it +will emit black-body radiation + +with exactly the intensity that +the black-body radiation would + +have on the outside if +the black body were still + +inside the cavity. + +So it radiates with exactly the +same intensity as the energy + +that it would receive if +it were inside the cavity. + +And furthermore, you +could even elaborate a bit + +on his argument to show that +the radiation that it radiates + +has exactly the same spectrum, +exactly the same decomposition + +into wavelengths, as +the black-body radiation + +inside the cavity. + +And the way to see +that is to imagine + +surrounding this black body by +absorption filters that only + +let through certain frequencies. + +And the point is that, no +matter what frequencies + +you limit going +through this filter, + +you have to stay in equilibrium. + +It will never get +hotter or colder. + +So that means that each +frequency by itself + +has to balance, has to have +exactly the same emission + +as it would have abortion +if the black body were just + +exposed to black-body +radiation surrounding it. + +So it radiates +black-body radiation. + +And the intensity +and spectrum must + +match what we call black-body +or cavity radiation. + +So the cavity radiation +has to exactly mimic + +the radiation emitted +by this black body. + +And that's the +motivation for calling it + +black-body radiation. + +Now, if this black body +absorbed some radiation + +and reflected some, then it +would emit different radiation. + +So it is important +that this body + +be black, in the sense that +it doesn't reflect anything. + +All radiation hitting +it is absorbed. + +And only under +that assumption do + +we know exactly what +it's going to emit. + +Yes? + +AUDIENCE: So is this +only true for right + +after you take it out? + +PROFESSOR: Well, it will start +to cool after you take it out. + +And as it cools, its +temperature will change. + +But if you account for +the changing temperature, + +it will be true at +anytime, actually. + +But the temperature will change. + +AUDIENCE: Because, +in the black cavity, + +it has things exciting it. + +And when you take +it out, there's + +no photons, no constant +radiation to excite it. + +So it can radiate-- + +PROFESSOR: Yes. + +Once you take it out, it's +no longer being excited. + +And I think, technically, +you're right. + +Once you take it out, +it will not only cool, + +but it will cease to be +at a uniform temperature. + +And that's basically +what we're saying + +if we're saying that the +atoms that are excited + +won't necessarily be in the +right thermal distribution + +as they would be if +it was on the inside. + +That would be a +statement that is not + +any longer in +thermal equilibrium. + +But as long as the +radiation is slow, + +you could just account for +the changing temperature. + +You would know how it radiates. + +And I think that's a +very good approximation. + +Although in principle, +it will cease + +to be in thermal equilibrium, +as soon as you take it out, + +the edges will be cool, +and the center will be hot. + +And you'd have to take into +account all of those things + +to be able to understand +how it radiates. + +Any other questions? + +OK, next, I want to +talk a little bit + +about what this +black-body radiation is. + +And one can begin by +trying to understand + +it purely classically, +which, of course, + +is what happened historically. + +In the 1800s, people tried to +understand cavity radiation + +or black-body radiation using +classical physics, Maxwell's + +equations, to describe +the radiation. + +And then, in a +nutshell-- we're just + +trying to establish +basic ideas here-- + +one can try to treat a field +statistical-mechanically + +by imagining not +fields in empty space, + +but fields in some +kind of a box. + +In this case, it +doesn't necessarily + +have to be the cavity +that we're talking about. + +It could be a big box that just +enclosed the system somehow + +to make it easier to talk about. + +And in the end, +you could imagine + +taking that box to infinity, +this theoretical box + +that you use to +simplify the problem. + +But once you put +the system in a box, + +then a field, like the +electromagnetic field, + +can always be broken +up into normal modes, + +standing wave patterns that have +an integer or a half integer + +number of wavelengths +inside the box. + +And no matter how complicated +the field is inside the box, + +you could always describe +it as a superposition + +of some set of standing waves. + +In general, it takes +an infinite number + +of standing wave components +to describe an arbitrary + +field-- that is, with shorter +and shorter wavelengths. + +But you can always-- and +this is Fourier's theorem-- + +you can always +describe an arbitrary + +field in terms of +the standing waves. + +And that's good for +the point of view + +of thinking about +statistical mechanics, + +because you could think +about each standing wave + +almost as if it were a particle. + +It really is a +harmonic oscillator. + +So if you think you know +the statistical mechanics + +of harmonic oscillators, +each standing wave in the box + +is just a harmonic +oscillator, so simple. + +We now try to ask what +is the thermodynamics + +of this system of +harmonic oscillators. + +And the rule for harmonic +oscillator is simple. + +Stat mech tells +you that you have + +1/2 kT per degree of freedom +in thermal equilibrium. + +The energy of a +system should just + +be 1/2 kT per degree of freedom. + +Having said that, all +the complicate questions + +come about by asking +ourselves what + +is meant by degree of freedom. + +But for the harmonic oscillator, +that has a simple answer. + +A harmonic oscillator +has two degrees + +of freedom-- the kinetic energy +and the potential energy. + +So the energy of a +harmonic oscillator + +should just be kT per +degree of freedom. + +And we could apply that to our +gas in the box and we could, + +ask how much energy +should the gas absorb + +at a given temperature? + +What should be the energy +density of the gas at a given + +temperature-- this +gas of photons. + +But it was noticed in +the 1900-- the 1800s + +that this doesn't work because +there's no limit to how short + +the wavelengths can be. + +And therefore, there's +not just some finite set + +of harmonic oscillators. + +There's an infinite +set of harmonic + +oscillators where you have +more and more harmonic + +oscillators at shorter +and shorter wavelengths + +ad infinitum, no limit. + +And that came to be +known as Jean's Paradox. + +So what it suggests is that +if this classical stat mech + +worked-- which obviously +it's not working. + +But if it did +work, it would mean + +that as you tried to put a gas +in just an empty box in contact + +with something at a +fixed temperature, + +the box would absorb more and +more energy without limit. + +And ultimately, it +would presumably + +cause the temperature +of the whatever + +is trying to maintain +the temperature + +to go to 0 as energy +gets siphoned off + +to shorter and shorter +wavelengths of excitations. + +That obviously isn't the +way the world behaves. + +We'd all freeze to +death if it did. + +So something has to +happen to save it. + +And it wasn't at all +obvious for many years + +what it was that saves it. + +But this Jean's +Paradox turns out + +to be saved by +quantum mechanics. + +And the important implication +of quantum mechanics + +is that the energy of +a harmonic oscillator + +is no longer allowed to +have any possible value, + +but is now quantized +as some integer times + +h times nu, the +frequency-- h being + +Planck's constant, +nu being frequency, n + +being some integer where +this integer might be called + +the excitation level of +the harmonic oscillator. + +Depending how you choose your +0, you might have an n plus 1/2 + +there. + +But that's not important +for us right now. + +It will be important +later actually. + +But for now, we'll just allow +ourselves to readjust the 0 + +and just think of it as n +times h nu, or h bar omega. + +Now, this makes +all the difference, + +statistical mechanically. + +One can apply +statistical mechanics + +using basically +the same principles + +to the quantum +mechanical system. + +And the key thing now is that +for the very short wavelengths, + +which are the ones that +were giving us trouble-- + +the infinities came +to short wavelengths. + +For the short wavelengths +where nu is high, h nu is high. + +And it means that +there's a minimum ante + +that you could put in to +excite those short wavelength + +harmonic oscillators. + +And it's a large number. + +You either put in a large +amount of energy or none at all. + +Quantum mechanics doesn't let +you do anything in between. + +Now remember, the +classical mechanics answer + +was that you have kT in +each harmonic oscillator. + +And kT would be small +compared to h nu, + +if we're talking about +a very short wavelength. + +So the classic +answer is just not + +allowed by quantum mechanics. + +You either have to put in +nothing or an amount much, much + +larger than the +classical answer. + +And when you do the statistical +mechanics quantum mechanically, + +which is not a big +deal really, you + +find that when you're +confronted with that choice, + +the most likely answer is +to put in no energy at all. + +So quantum mechanics freezes out +these short wavelength modes. + +And then the n produces +a finite energy density + +for a gas of photons. + +Yes? + +AUDIENCE: Seems like +if you were to sum over + +like all the possible +wave numbers, that-- well, + +so the energy is inversely +related to wavelength, right? + +So even if you quantize it, +like for large wavelengths, + +isn't the sum still like a sum +of one over lambda wavelength, + +with its derivative? + +PROFESSOR: You're +saying, isn't there also + +a divergence at the +large wavelength n? + +AUDIENCE: Because +that sum doesn't + +seem like it would work. + +PROFESSOR: Right. + +No, that's important. + +The reason that's +not a problem is + +that if you're talking +about the energy in a box, + +the wavelength can't +be bigger than the box. + +The largest possible +wavelength is twice the box so + +that half a wavelength +fits in the box. + +If you're talking about the +energy in the whole infinite + +universe, then we expect +the answer to infinite. + +And it is. + +There's no problem with +having infinite total energy + +if you want to have +a finite energy + +density throughout +an infinite universe. + +So the size of the box cuts +off the large wavelengths. + +And quantum mechanics cuts +off the small wavelengths. + +So in the end, one does +get a finite answer + +for the energy density +of black-body radiation. + +And that's crucial +for our survival, + +crucial for the +existence of the universe + +as we know it, and also +crucial for the calculations + +that we're about to do. + +OK, so when one does these +calculations initially + +for photons only, what we'd +find is that the energy density + +is equal to a fudge factor, +which I'm going to call g. + +And you'll see later why I'm +introducing a fudge factor. + +For now, g is just 2. + +But later, we'll generalize the +application of this formula, + +and g will have +different values. + +But for now, we're +dealing with photons. + +There's a factor of 2 there, +but I'm going to write 2 as g, + +writing g equals 2 underneath. + +And then the pi +squared over 30-- + +you can really +calculate this-- times + +kT to the fourth power divided +by h bar c cubed, h bar + +being Plank's constant +divided by 2 pi and little k + +being Boltzmann constant. + +So this is calculated just by +thinking of the gas in a box + +as a lot of harmonic oscillators +and applying standard stat + +mech to each +harmonic oscillator, + +but you apply the quantum +mechanical version of the stat + +mech to each +harmonic oscillator. + +And you can also find, by doing +the same kind of analysis, + +that the pressure is +1/3 the energy density, + +which we also derived +earlier by different means. + +And it's all consistent so you +get the same answer every time, + +even if you think +about it differently. + +So here, I have mine deriving +it directly from the stat mech. + +You can also, from +the stat mech, + +calculate the number density of +photons in thermal equilibrium. + +And that will be equal to -- +again, there's a factor of 2. + +But this time, I'll +call the factor + +of 2 g star, where g star +also equals 2 for photons. + +But when we generalize +these formulas, + +g will not necessarily +equal g star, + +which is why I'm +giving it two names. + +And this g star +multiplies zeta of 3, + +where zeta refers to the +Riemann zeta function, which + +I'll define in a second, +divided by pi squared times + +kT cubed divided +by h bar c cubed. + +OK. + +OK, so I need to +define this zeta of 3. + +It's 1 over 1 cubed plus 1 over +2 cubed plus 1 over 3 cubed + +plus dot dot dot. + +It's an infinite series. + +And if you sum up +that infinite series, + +at least to three decimal +places, it's 1.202. + +OK, then there's +one other formula + +that will be of interest to us. + +And that'll be a formula +for the entropy density. + +Now, if you've had +a stat mech course, + +you have some idea of what +entropy density means. + +If you have not, suffice +it to say for this class + +that it is some measure of +the disorder in the sense + +of the total number of +different quantum states + +that contribute to a given +macroscopic description. + +The more different +microstates there + +are that contribute to a +macroscopic description, + +the higher the entropy. + +And the other important +thing about entropy to us + +besides that vague definition-- +which will be enough-- + +but the important +thing for us is + +that under most circumstances, +entropy will be conserved. + +It's conserved as +long as things stay + +at or near thermal equilibrium. + +And in the early universe +as the universe expands, + +that's the case. + +So for us, the +entropy of our gas + +will simply be a +conserved quantity + +that we can make use of. + +And we will make use of +it in some important ways. + +And we could write +down a formula + +for the entropy +density of photons. + +And it's g, where this g in +fact the same g as over there. + +It is related to the energy. + +So it's the same g that +appears in two cases, 2 + +in both cases for +protons by themselves. + +And then there are factors +that you can calculate-- + +2 pi squared over 45 times k to +the fourth T cubed over h bar + +c cubed. + +OK, this time, the number +of k's and T's do not match. + +That's mainly due to +the conventions about + +how entropy is defined. + +It's not really anything deep. + +I might mention at +this point that the 2's + +that I've been writing for +everything-- g equals 2, + +g star equals 2-- the +reason those 2's are written + +explicitly rather than just +absorbing the factor of 2 + +into the other factors is +that photons are characterized + +by the fact that there are +two polarizations of photons. + +So if I have a beam +of photons, they + +could be right-handed +or left-handed. + +And anything else +could be considered + +a superposition of those two. + +So there are two +independent polarizations. + +And it's useful to keep +track of these formulas + +as the amount of energy +density per polarization. + +Thus, different +kinds of particles + +will have different +numbers of polarizations. + +So if we know the +amount per polarization, + +we'll be able to more easily +apply it to other particles. + +Yes? + +AUDIENCE: Sorry, just to kind +of bring up the same question, + +if we-- I read that +in the early universe, + +the temperature is constantly +changing or it's cooling. + +PROFESSOR: Right. + +AUDIENCE: So then if the +temperature is changing, + +then how can we say that +the entropy is constant? + +PROFESSOR: OK, +important question-- + +we'll be getting +to it very soon. + +But since you asked the +question, I'll ask it now. + +The question was if the +universe is expanding, + +and the entropy +density is going down + +because it thins, +how can that happen-- + +I guess it was asked +the other way around. + +If the temperature +is falling, how + +can entropy be +conserved if this is + +the formula for entropy density? + +And the answer-- when I tell +you, you'll see it's obvious. + +We don't expect +the entropy density + +to be conserved if the +entropy is conserved. + +The entropy thins out +as the universe expands. + +So if we just had a gas +with nothing else changing, + +we expect the entropy density +to go down like 1 over the scale + +factor cubed, just like the +number density of particles. + +So if s is going to go down like +1 over the scale factor cubed, + +that would be consistent +with this formula + +if the temperature also fell +as 1 over the scale factor. + +So that to cubing it +made things match. + +And that's what we'll find. + +The temperature falls off, +like 1 over the scale factor. + +And that's consistent +with everything + +that we said about energy +densities and so on. + +OK. + +Next thing I want +to talk about is + +neutrinos, which +I told you earlier + +contributes in a significant +way to the radiation energy + +density in the universe today. + +Neutrinos are particles +which for a long time, + +were thought to be massless. + +Until around 2000 +or so, neutrinos + +were thought to be massless. + +Now we know that in fact, they +have a very small mass, which + +complicates the +description here. + +It turns out that +cosmologically, neutrinos + +still act as if +they were massless + +for almost all purposes +and for really all purposes + +that we'll be dealing with in +this class, although if we were + +interested in the effects +of neutrinos on structure + +formation, we'd be +interested in whether or not + +the neutrinos have a +small mass or whether it's + +smaller than that. + +We know it's non-zero. + +We don't know what the +neutrino mass is, by the way. + +What we actually know +from observations + +is that there are three +types of neutrinos. + +And those are called flavors. + +And I'll use the letter +nu for the word neutrino. + +And those three +types of neutrinos + +are called nu sub e, called +the electron neutrino; + +nu subbed mu, called the muon +neutrino, and nu sub tau, + +called the tau neutrino. + +And these letters e, mu, and tau +link to the names of particles. + +This is the electron neutrino. + +This is the muon +neutrino connected + +to a particle called +the muon, which + +is like the electron but +heavier and different. + +And this is linked to a particle +called the tau, which is also + +like the electron but much more +heavier but otherwise similar + +in its properties. + +And the neutrinos are +linked in the sense + +that when a neutrino +is produced, depending + +on how you start, it is +very typically produced + +in conjunction with one +of these other particles. + +So an electron +neutrino is typically + +produced in conjunction +with an electron. + +And similarly, a muon +neutrino is typically + +produced in conjunction +with a muon. + +And a tau neutrino is typically +produced in conjunction + +with a tau. + +Now, what does this have +to do with neutrino masses? + +We've never actually measured +the mass of neutrino. + +So we only know that they +have mass indirectly. + +What we have seen is one +flavor of neutrino turn + +into another flavor. + +And it turns out, in the +context of quantum field theory + +and I think this does make +a certain amount of sense + +just by intuition, if +a particle is massless, + +it can never change +into anything. + +The process by which +one changes into another + +is pretty quantum +mechanical and a little hard + +to understand anyway. + +But if the particles +were really massless, + +they would move at +the speed of light. + +And if the particles were +moving at the speed of light, + +if the particle had any kind +of a clock on the particle, + +that clock would literally +stop with the particle + +moving at the speed of light. + +So if particles are massless, +any internal workings + +that that particle +might have to be frozen. + +That is, if it's a +clock, it has to be + +a clock that's +stopped completely. + +And for reasons that +are essentially that, + +although they can be made +more formal and more rigorous, + +a truly massless +particle could never + +undergo any kind +of change whatever. + +It would have to +stay exactly like it + +looks like to start with. + +Because it just has no time. + +So the fact that these +neutrinos turn into each other + +implies that they must +have a nonzero mass. + +It must not really be moving +at quite the speed of light. + +And that's the way +the formalism works. + +And we could set +limits on the masses + +based on what we know about +the transitions between one + +kind of neutrino and another. + +Yes? + +AUDIENCE: How do we +explain photon decaying + +to an electron-positron +pair then? + +PROFESSOR: A photon decaying +to an electron-positron pair? + +AUDIENCE: Yeah. + +PROFESSOR: The answer is a +free photon never does decay + +to an electron-positron pair. + +Photons can collide +with something + +and produce an +electron-positron pair. + +But that collision, that's +a more complicated process. + +What I'm saying is-- I'm sorry. + +This process of conversion-- +maybe I should have clarified-- + +happens just as the +neutrinos travel. + +It's not due to collisions. + +Due to collsions, +complicated things + +can happen whether the +particle is massless or not. + +But a massless particle simply +in transit cannot undergo any + +kind of transition. + +And these neutrinos are seen +to undergo transitions simply + +being in transit +without any collisions. + +In terms of my clock +analogy and a stopped clock, + +I think the reason +the photon can convert + +into electron-positron pairs +if it collides with something + +is that when it collides, it +essentially breaks the clock. + +You don't have a +photon that's just + +moving along without +time anymore. + +OK, so these +neutrinos have masses. + +And maybe I should, +at this point, + +write down some bounds +on these masses. + +m squared 21 times c to the +fourth is equal to 7.50 plus + +or minus 0.2 times 10 to the +minus 5 electron volts squared. + +These numbers come from the +latest particle data tables, + +which I gave references +for in the notes. + +So this is the difference +of the mass squared. + +And delta m 23 squared +times c to the fourth + +to turn it into the +square of an energy + +is 2.32 plus 0.12 +minus 0.08 times 10 + +to the minus third +electron volts squared. + +So one thing you +notice immediately + +is that these are +incredibly small masses. + +Remember, the proton +weighs 938 MeV, + +three million electron volts. + +And these are fractions +of one electron volt. + +So by the standards +of particle physics, + +these are unbelievably +small energies, + +unbelievably small +mass differences. + +But they're there. + +They have to be there for the +physics we know to make sense. + +The other thing +that you may notice + +about this notation-- which +I don't want to elaborate + +on but I'll just mention-- +this is called 21. + +This is called 23. + +There's no 1, 2, or 3 there. + +There's an e and a mu and a tau. + +The complication here is +something very quantum + +mechanical. + +The e, mu and tau +labels are labels + +which basically label +the neutrino according + +to how the neutrino is created. + +It turns out that their mass +eigenstates-- states which + +actually have a +definite mass-- are not + +the e, the mu or the tau. + +In fact, if the e +had a definite mass, + +that would be saying +that an e would just + +propagate as a particle +with a certain mass. + +It would not convert +into anything else. + +The fact that an e converts +into other particles-- + +a nu sub e converts +into other particles + +is really the statement +that nu sub e is not + +a state with a definite mass. + +But there are states +with definite masses + +which could be expressed quantum +mechanically as superpositions + +of these flavor eigenstates. + +So nu sub 1, nu +sub 2 and nu sub 3 + +are states of neutrinos +that have definite masses. + +And each one of them is +a superposition of nu sub + +e, nu sub mu and nu sub tau. + +Yes? + +AUDIENCE: How come we don't +have a delta n from 31? + +PROFESSOR: Good question. + +I think it's just the +lack of knowledge. + +I don't think there's any +reason it's not defined. + +I'm sure it is defined. + +I think it's just +lack of knowledge. + +And if I knew more details about +how these things were measured, + +I could give you a +better story about that. + +But I don't, frankly. + +So in the end, it's a rather +complicated quantum mechanical + +system which we're not going +to go into any details about. + +What more should I say today? + +OK, let me just +mention for today + +and we'll continue next +time after the quiz, + +for our purposes, we're going +to treat these neutrinos + +as if they're massless. + +And it turns out that that's +actually extraordinarily + +accurate from the point +of view of cosmology, + +at least for the +kind of cosmology + +that we're doing +where we're just + +interested in the effect +of these neutrinos + +on the expansion +rate of the universe. + +And treating them as +massless particles, + +I will shortly give +you the formulas + +for how they contribute to +the black-body radiation. + +But it I think there's no +point in my writing them now. + +I'll just write them again in +the beginning of next period. + +But they do contribute to +the black-body radiation + +and in a way that we actually +know how to calculate. + +And they have a +noticeable effect + +on the evolution +of our universe. + +OK, that's all for today. + +Good luck on the +quiz on Thursday. + +I'll be here to help proctor. + +I think Tim [INAUDIBLE] +will be here too. + +And I'll see you more intimately +either at my office hour + +tomorrow or at lecture +a week from now. \ No newline at end of file diff --git a/6mndLA1SceA.txt b/6mndLA1SceA.txt new file mode 100644 index 0000000000000000000000000000000000000000..e44aab1af3e057ea992186064f0081848247d460 --- /dev/null +++ b/6mndLA1SceA.txt @@ -0,0 +1,1131 @@ +align:start position:0% + +hi there my name is Gloria chair and for + + align:start position:0% +hi there my name is Gloria chair and for + + + align:start position:0% +hi there my name is Gloria chair and for +the next few minutes I'll be talking + + align:start position:0% +the next few minutes I'll be talking + + + align:start position:0% +the next few minutes I'll be talking +about how to find the perfect diamond + + align:start position:0% +about how to find the perfect diamond + + + align:start position:0% +about how to find the perfect diamond +and why that might actually be + + align:start position:0% +and why that might actually be + + + align:start position:0% +and why that might actually be +impossible let's start with what a + + align:start position:0% +impossible let's start with what a + + + align:start position:0% +impossible let's start with what a +perfect diamond looks like a quick + + align:start position:0% +perfect diamond looks like a quick + + + align:start position:0% +perfect diamond looks like a quick +google image search for the perfect + + align:start position:0% +google image search for the perfect + + + align:start position:0% +google image search for the perfect +diamond you've just asked as the first + + align:start position:0% +diamond you've just asked as the first + + + align:start position:0% +diamond you've just asked as the first +result and it does look pretty perfect + + align:start position:0% +result and it does look pretty perfect + + + align:start position:0% +result and it does look pretty perfect +but just because it looks perfect + + align:start position:0% +but just because it looks perfect + + + align:start position:0% +but just because it looks perfect +doesn't mean that it actually is to + + align:start position:0% +doesn't mean that it actually is to + + + align:start position:0% +doesn't mean that it actually is to +determine if a diamond is really perfect + + align:start position:0% +determine if a diamond is really perfect + + + align:start position:0% +determine if a diamond is really perfect +we have to look at its structure a + + align:start position:0% +we have to look at its structure a + + + align:start position:0% +we have to look at its structure a +diamond consists of carbon atoms + + align:start position:0% +diamond consists of carbon atoms + + + align:start position:0% +diamond consists of carbon atoms +arranged in what we call a crystal + + align:start position:0% +arranged in what we call a crystal + + + align:start position:0% +arranged in what we call a crystal +structure + + align:start position:0% +structure + + + align:start position:0% +structure +more specifically diamonds from diamonds + + align:start position:0% +more specifically diamonds from diamonds + + + align:start position:0% +more specifically diamonds from diamonds +form a cubic crystal structure made up + + align:start position:0% +form a cubic crystal structure made up + + + align:start position:0% +form a cubic crystal structure made up +of tetrahedrally arranged atoms as shown + + align:start position:0% +of tetrahedrally arranged atoms as shown + + + align:start position:0% +of tetrahedrally arranged atoms as shown +in this 2d depiction an important thing + + align:start position:0% +in this 2d depiction an important thing + + + align:start position:0% +in this 2d depiction an important thing +to note is that diamonds are not a + + align:start position:0% +to note is that diamonds are not a + + + align:start position:0% +to note is that diamonds are not a +stable form of carbon they're what we + + align:start position:0% +stable form of carbon they're what we + + + align:start position:0% +stable form of carbon they're what we +call metastable which means that they + + align:start position:0% +call metastable which means that they + + + align:start position:0% +call metastable which means that they +are energetically unfavorable but there + + align:start position:0% +are energetically unfavorable but there + + + align:start position:0% +are energetically unfavorable but there +is a high activation energy for it to + + align:start position:0% +is a high activation energy for it to + + + align:start position:0% +is a high activation energy for it to +decompose so it stays how it is for a + + align:start position:0% +decompose so it stays how it is for a + + + align:start position:0% +decompose so it stays how it is for a +very long time besides the fact that + + align:start position:0% +very long time besides the fact that + + + align:start position:0% +very long time besides the fact that +diamonds aren't forever + + align:start position:0% +diamonds aren't forever + + + align:start position:0% +diamonds aren't forever +what really makes finding the perfect + + align:start position:0% +what really makes finding the perfect + + + align:start position:0% +what really makes finding the perfect +one impossible is that it probably + + align:start position:0% +one impossible is that it probably + + + align:start position:0% +one impossible is that it probably +doesn't even exist what real diamonds + + align:start position:0% +doesn't even exist what real diamonds + + + align:start position:0% +doesn't even exist what real diamonds +look like it's something like this it's + + align:start position:0% +look like it's something like this it's + + + align:start position:0% +look like it's something like this it's +the same structure as the last slide but + + align:start position:0% +the same structure as the last slide but + + + align:start position:0% +the same structure as the last slide but +there's a carbon atom missing this is + + align:start position:0% +there's a carbon atom missing this is + + + align:start position:0% +there's a carbon atom missing this is +called the vacancy which is a type of + + align:start position:0% +called the vacancy which is a type of + + + align:start position:0% +called the vacancy which is a type of +defect that can exist in crystals like + + align:start position:0% +defect that can exist in crystals like + + + align:start position:0% +defect that can exist in crystals like +diamond defects are imperfections in + + align:start position:0% +diamond defects are imperfections in + + + align:start position:0% +diamond defects are imperfections in +crystals and vacancies are not the only + + align:start position:0% +crystals and vacancies are not the only + + + align:start position:0% +crystals and vacancies are not the only +kinds all crystals in the real world + + align:start position:0% +kinds all crystals in the real world + + + align:start position:0% +kinds all crystals in the real world +have a number of defects ranging from + + align:start position:0% +have a number of defects ranging from + + + align:start position:0% +have a number of defects ranging from +vacancies or grain boundaries to edge + + align:start position:0% +vacancies or grain boundaries to edge + + + align:start position:0% +vacancies or grain boundaries to edge +dislocations there's quite a number of + + align:start position:0% +dislocations there's quite a number of + + + align:start position:0% +dislocations there's quite a number of +them but for the purpose of this video + + align:start position:0% +them but for the purpose of this video + + + align:start position:0% +them but for the purpose of this video +I'll be referencing vacancies in + + align:start position:0% +I'll be referencing vacancies in + + + align:start position:0% +I'll be referencing vacancies in +diamonds + + align:start position:0% +diamonds + + + align:start position:0% +diamonds +keep in mind that anything I say about + + align:start position:0% +keep in mind that anything I say about + + + align:start position:0% +keep in mind that anything I say about +them also applies to other kinds of + + align:start position:0% +them also applies to other kinds of + + + align:start position:0% +them also applies to other kinds of +defects and other kinds of crystals okay + + align:start position:0% +defects and other kinds of crystals okay + + + align:start position:0% +defects and other kinds of crystals okay +so now that we know why crystals aren't + + align:start position:0% +so now that we know why crystals aren't + + + align:start position:0% +so now that we know why crystals aren't +perfect we want to know why this happens + + align:start position:0% +perfect we want to know why this happens + + + align:start position:0% +perfect we want to know why this happens +to begin with the reason that these + + align:start position:0% +to begin with the reason that these + + + align:start position:0% +to begin with the reason that these +defects form is because a crystal will + + align:start position:0% +defects form is because a crystal will + + + align:start position:0% +defects form is because a crystal will +always be tending to equilibrium + + align:start position:0% +always be tending to equilibrium + + + align:start position:0% +always be tending to equilibrium +also known as the state of lowest Gibbs + + align:start position:0% +also known as the state of lowest Gibbs + + + align:start position:0% +also known as the state of lowest Gibbs +free energy the formation of defects in + + align:start position:0% +free energy the formation of defects in + + + align:start position:0% +free energy the formation of defects in +a crystal may seem counterintuitive + + align:start position:0% +a crystal may seem counterintuitive + + + align:start position:0% +a crystal may seem counterintuitive +because it it costs energy which is not + + align:start position:0% +because it it costs energy which is not + + + align:start position:0% +because it it costs energy which is not +favorable + + align:start position:0% +favorable + + + align:start position:0% +favorable +but the formation of defects also + + align:start position:0% +but the formation of defects also + + + align:start position:0% +but the formation of defects also +increases the amount of entropy in which + + align:start position:0% +increases the amount of entropy in which + + + align:start position:0% +increases the amount of entropy in which +in the system which is favorable the + + align:start position:0% +in the system which is favorable the + + + align:start position:0% +in the system which is favorable the +entropy gain can sometimes outweigh the + + align:start position:0% +entropy gain can sometimes outweigh the + + + align:start position:0% +entropy gain can sometimes outweigh the +energy cost of forming a defect so a + + align:start position:0% +energy cost of forming a defect so a + + + align:start position:0% +energy cost of forming a defect so a +perfect crystal can actually decrease + + align:start position:0% +perfect crystal can actually decrease + + + align:start position:0% +perfect crystal can actually decrease +its Gibbs free energy by forming defects + + align:start position:0% +its Gibbs free energy by forming defects + + + align:start position:0% +its Gibbs free energy by forming defects +this can be seen in the following + + align:start position:0% +this can be seen in the following + + + align:start position:0% +this can be seen in the following +equation where Delta G equals Delta H + + align:start position:0% +equation where Delta G equals Delta H + + + align:start position:0% +equation where Delta G equals Delta H +minus T Delta s so formation of defects + + align:start position:0% +minus T Delta s so formation of defects + + + align:start position:0% +minus T Delta s so formation of defects +becomes a battle of enthalpy versus + + align:start position:0% +becomes a battle of enthalpy versus + + + align:start position:0% +becomes a battle of enthalpy versus +entropy if the enthalpy cost of forming + + align:start position:0% +entropy if the enthalpy cost of forming + + + align:start position:0% +entropy if the enthalpy cost of forming +a defect is greater than the entropy + + align:start position:0% +a defect is greater than the entropy + + + align:start position:0% +a defect is greater than the entropy +increase of the system then the defect + + align:start position:0% +increase of the system then the defect + + + align:start position:0% +increase of the system then the defect +does not form if the entropy increase of + + align:start position:0% +does not form if the entropy increase of + + + align:start position:0% +does not form if the entropy increase of +the system is greater than the cost of + + align:start position:0% +the system is greater than the cost of + + + align:start position:0% +the system is greater than the cost of +forming a defect then the defect does + + align:start position:0% +forming a defect then the defect does + + + align:start position:0% +forming a defect then the defect does +form the change in Gibbs energy of + + align:start position:0% +form the change in Gibbs energy of + + + align:start position:0% +form the change in Gibbs energy of +forming vacancies depends on several + + align:start position:0% +forming vacancies depends on several + + + align:start position:0% +forming vacancies depends on several +factors including the number of + + align:start position:0% +factors including the number of + + + align:start position:0% +factors including the number of +vacancies already present and the size + + align:start position:0% +vacancies already present and the size + + + align:start position:0% +vacancies already present and the size +of the crystal so the energy cost an + + align:start position:0% +of the crystal so the energy cost an + + + align:start position:0% +of the crystal so the energy cost an +entropy contribution of vacancy + + align:start position:0% +entropy contribution of vacancy + + + align:start position:0% +entropy contribution of vacancy +formation actually changes with each + + align:start position:0% +formation actually changes with each + + + align:start position:0% +formation actually changes with each +defect formed what we see is that + + align:start position:0% +defect formed what we see is that + + + align:start position:0% +defect formed what we see is that +there's actually happy spot for the + + align:start position:0% +there's actually happy spot for the + + + align:start position:0% +there's actually happy spot for the +equilibrium amounts of vacancies this + + align:start position:0% +equilibrium amounts of vacancies this + + + align:start position:0% +equilibrium amounts of vacancies this +here is a visualization of how the + + align:start position:0% +here is a visualization of how the + + + align:start position:0% +here is a visualization of how the +number of vacancies affect the Gibbs + + align:start position:0% +number of vacancies affect the Gibbs + + + align:start position:0% +number of vacancies affect the Gibbs +free energy of a crystal at various + + align:start position:0% +free energy of a crystal at various + + + align:start position:0% +free energy of a crystal at various +temperatures on the left is a plot of + + align:start position:0% +temperatures on the left is a plot of + + + align:start position:0% +temperatures on the left is a plot of +Gibbs free energy where x axis + + align:start position:0% +Gibbs free energy where x axis + + + align:start position:0% +Gibbs free energy where x axis +represents the number of vacancies that + + align:start position:0% +represents the number of vacancies that + + + align:start position:0% +represents the number of vacancies that +can occur in a crystal and the y axis + + align:start position:0% +can occur in a crystal and the y axis + + + align:start position:0% +can occur in a crystal and the y axis +represents two Gibbs energy of the + + align:start position:0% +represents two Gibbs energy of the + + + align:start position:0% +represents two Gibbs energy of the +system on the right is a visualization + + align:start position:0% +system on the right is a visualization + + + align:start position:0% +system on the right is a visualization +of what the lattice looks like at + + align:start position:0% +of what the lattice looks like at + + + align:start position:0% +of what the lattice looks like at +equilibrium in this demo the crystal is + + align:start position:0% +equilibrium in this demo the crystal is + + + align:start position:0% +equilibrium in this demo the crystal is +a square lattice made it for 400 atom + + align:start position:0% +a square lattice made it for 400 atom + + + align:start position:0% +a square lattice made it for 400 atom +sites I am using a 2d square lattice + + align:start position:0% +sites I am using a 2d square lattice + + + align:start position:0% +sites I am using a 2d square lattice +instead of a 3-dimensional diamond + + align:start position:0% +instead of a 3-dimensional diamond + + + align:start position:0% +instead of a 3-dimensional diamond +lattice for ease of viewing and + + align:start position:0% +lattice for ease of viewing and + + + align:start position:0% +lattice for ease of viewing and +understanding this topic these concepts + + align:start position:0% +understanding this topic these concepts + + + align:start position:0% +understanding this topic these concepts +applying the same way to Diamond + + align:start position:0% +applying the same way to Diamond + + + align:start position:0% +applying the same way to Diamond +crystals which are much more complicated + + align:start position:0% +crystals which are much more complicated + + + align:start position:0% +crystals which are much more complicated +as you can see already there is a + + align:start position:0% +as you can see already there is a + + + align:start position:0% +as you can see already there is a +vacancy present in the slot it may be a + + align:start position:0% +vacancy present in the slot it may be a + + + align:start position:0% +vacancy present in the slot it may be a +bit difficult to see on the left but + + align:start position:0% +bit difficult to see on the left but + + + align:start position:0% +bit difficult to see on the left but +this is because a at equilibrium the + + align:start position:0% +this is because a at equilibrium the + + + align:start position:0% +this is because a at equilibrium the +Gibbs free energy plant is actually not + + align:start position:0% +Gibbs free energy plant is actually not + + + align:start position:0% +Gibbs free energy plant is actually not +linear but curved it becomes more + + align:start position:0% +linear but curved it becomes more + + + align:start position:0% +linear but curved it becomes more +apparent as we increase the temperature + + align:start position:0% +apparent as we increase the temperature + + + align:start position:0% +apparent as we increase the temperature +higher temperatures provide greater + + align:start position:0% +higher temperatures provide greater + + + align:start position:0% +higher temperatures provide greater +entropy increase of defect formation so + + align:start position:0% +entropy increase of defect formation so + + + align:start position:0% +entropy increase of defect formation so +we see vacancies are more likely to form + + align:start position:0% +we see vacancies are more likely to form + + + align:start position:0% +we see vacancies are more likely to form +here we can see that the lowest Gibbs + + align:start position:0% +here we can see that the lowest Gibbs + + + align:start position:0% +here we can see that the lowest Gibbs +free energy doesn't occur at zero but + + align:start position:0% +free energy doesn't occur at zero but + + + align:start position:0% +free energy doesn't occur at zero but +actually at around 50 vacancies per 400 + + align:start position:0% +actually at around 50 vacancies per 400 + + + align:start position:0% +actually at around 50 vacancies per 400 +sites this seems pretty high but if you + + align:start position:0% +sites this seems pretty high but if you + + + align:start position:0% +sites this seems pretty high but if you +think about it this is at 5000 Kelvin so + + align:start position:0% +think about it this is at 5000 Kelvin so + + + align:start position:0% +think about it this is at 5000 Kelvin so +the amount or so the atoms in the + + align:start position:0% +the amount or so the atoms in the + + + align:start position:0% +the amount or so the atoms in the +diamond crystal are actually moving + + align:start position:0% +diamond crystal are actually moving + + + align:start position:0% +diamond crystal are actually moving +around quite a bit so it makes sense + + align:start position:0% +around quite a bit so it makes sense + + + align:start position:0% +around quite a bit so it makes sense +that you won't find all of the atoms in + + align:start position:0% +that you won't find all of the atoms in + + + align:start position:0% +that you won't find all of the atoms in +the right places if you would like to + + align:start position:0% +the right places if you would like to + + + align:start position:0% +the right places if you would like to +see how this visualization was made the + + align:start position:0% +see how this visualization was made the + + + align:start position:0% +see how this visualization was made the +code is accompanied with this video in + + align:start position:0% +code is accompanied with this video in + + + align:start position:0% +code is accompanied with this video in +summary what we found is that the + + align:start position:0% +summary what we found is that the + + + align:start position:0% +summary what we found is that the +perfect crystals don't exist because the + + align:start position:0% +perfect crystals don't exist because the + + + align:start position:0% +perfect crystals don't exist because the +equilibrium state of lowest Gibbs free + + align:start position:0% +equilibrium state of lowest Gibbs free + + + align:start position:0% +equilibrium state of lowest Gibbs free +energy curves with some number of + + align:start position:0% +energy curves with some number of + + + align:start position:0% +energy curves with some number of +defects + + align:start position:0% +defects + + + align:start position:0% +defects +since diamonds are crystals it turns out + + align:start position:0% +since diamonds are crystals it turns out + + + align:start position:0% +since diamonds are crystals it turns out +that finding a perfect one is impossible + + align:start position:0% +that finding a perfect one is impossible + + + align:start position:0% +that finding a perfect one is impossible +but that doesn't mean we can't find a + + align:start position:0% +but that doesn't mean we can't find a + + + align:start position:0% +but that doesn't mean we can't find a +diamond that looks perfect thanks for + + align:start position:0% +diamond that looks perfect thanks for + + + align:start position:0% +diamond that looks perfect thanks for +listening and I hope this quick lesson + + align:start position:0% +listening and I hope this quick lesson + + + align:start position:0% +listening and I hope this quick lesson +has made understanding why defects form + + align:start position:0% +has made understanding why defects form + + + align:start position:0% +has made understanding why defects form +a little clearer the notebook that + + align:start position:0% +a little clearer the notebook that + + + align:start position:0% +a little clearer the notebook that +accompanies this video is a version of + + align:start position:0% +accompanies this video is a version of + + + align:start position:0% +accompanies this video is a version of +this video and with that I would like to + + align:start position:0% +this video and with that I would like to + + + align:start position:0% +this video and with that I would like to +thank professor Carter and professor + + align:start position:0% +thank professor Carter and professor + + + align:start position:0% +thank professor Carter and professor +King and the help of Durio 160 a's emma + + align:start position:0% +King and the help of Durio 160 a's emma + + + align:start position:0% +King and the help of Durio 160 a's emma +berhan and philippe \ No newline at end of file diff --git a/6vgHIImFwHo.txt b/6vgHIImFwHo.txt new file mode 100644 index 0000000000000000000000000000000000000000..42f47eb87dbcc58a4f035f26ec0cec7fcb72bfd6 --- /dev/null +++ b/6vgHIImFwHo.txt @@ -0,0 +1,1715 @@ +align:start position:0% + +okay so how do we find these stable + + align:start position:0% +okay so how do we find these stable + + + align:start position:0% +okay so how do we find these stable +marriages well there's a procedure for + + align:start position:0% +marriages well there's a procedure for + + + align:start position:0% +marriages well there's a procedure for +doing it which is kind of elegantly + + align:start position:0% +doing it which is kind of elegantly + + + align:start position:0% +doing it which is kind of elegantly +described as a day-by-day mating ritual + + align:start position:0% +described as a day-by-day mating ritual + + + align:start position:0% +described as a day-by-day mating ritual +that the boys and the girls cooperate in + + align:start position:0% +that the boys and the girls cooperate in + + + align:start position:0% +that the boys and the girls cooperate in +so let's see what happens on the first + + align:start position:0% +so let's see what happens on the first + + + align:start position:0% +so let's see what happens on the first +day um on the morning of the first day + + align:start position:0% +day um on the morning of the first day + + + align:start position:0% +day um on the morning of the first day +each boy looks at his list of girls and + + align:start position:0% +each boy looks at his list of girls and + + + align:start position:0% +each boy looks at his list of girls and +picks the one that he likes the best at + + align:start position:0% +picks the one that he likes the best at + + + align:start position:0% +picks the one that he likes the best at +the top of his list and he goes off and + + align:start position:0% +the top of his list and he goes off and + + + align:start position:0% +the top of his list and he goes off and +serenades her or proposes to her + + align:start position:0% +serenades her or proposes to her + + + align:start position:0% +serenades her or proposes to her +so here we have Billy Bob and Brad + + align:start position:0% +so here we have Billy Bob and Brad + + + align:start position:0% +so here we have Billy Bob and Brad +proposing to Angelina that means that on + + align:start position:0% +proposing to Angelina that means that on + + + align:start position:0% +proposing to Angelina that means that on +the first day uh Angelina was at the top + + align:start position:0% +the first day uh Angelina was at the top + + + align:start position:0% +the first day uh Angelina was at the top +of both Brad's list and Billy Bob's list + + align:start position:0% +of both Brad's list and Billy Bob's list + + + align:start position:0% +of both Brad's list and Billy Bob's list +and they're both going to be proposing + + align:start position:0% +and they're both going to be proposing + + + align:start position:0% +and they're both going to be proposing +and asking if she's willing to marry + + align:start position:0% +and asking if she's willing to marry + + + align:start position:0% +and asking if she's willing to marry +them well in the afternoon uh each girl + + align:start position:0% +them well in the afternoon uh each girl + + + align:start position:0% +them well in the afternoon uh each girl +rejects all but her favorite Suitor so + + align:start position:0% +rejects all but her favorite Suitor so + + + align:start position:0% +rejects all but her favorite Suitor so +in this case Angelina likes Brad best + + align:start position:0% +in this case Angelina likes Brad best + + + align:start position:0% +in this case Angelina likes Brad best +ofal so she says to everybody else if + + align:start position:0% +ofal so she says to everybody else if + + + align:start position:0% +ofal so she says to everybody else if +you're not Brad take a hike and that's + + align:start position:0% +you're not Brad take a hike and that's + + + align:start position:0% +you're not Brad take a hike and that's +what happened at that stage and then in + + align:start position:0% +what happened at that stage and then in + + + align:start position:0% +what happened at that stage and then in +the evening here we look at rejected Boy + + align:start position:0% +the evening here we look at rejected Boy + + + align:start position:0% +the evening here we look at rejected Boy +Billy Bob a boy who's rejected crosses + + align:start position:0% +Billy Bob a boy who's rejected crosses + + + align:start position:0% +Billy Bob a boy who's rejected crosses +off the girl who rejected him so Billy + + align:start position:0% +off the girl who rejected him so Billy + + + align:start position:0% +off the girl who rejected him so Billy +Bob is going to cross Angelino off his + + align:start position:0% +Bob is going to cross Angelino off his + + + align:start position:0% +Bob is going to cross Angelino off his +list and then the whole ritual is going + + align:start position:0% +list and then the whole ritual is going + + + align:start position:0% +list and then the whole ritual is going +to repeat starting the next morning + + align:start position:0% +to repeat starting the next morning + + + align:start position:0% +to repeat starting the next morning +except that now Billy Bob will have a + + align:start position:0% +except that now Billy Bob will have a + + + align:start position:0% +except that now Billy Bob will have a +different woman at the top of his list + + align:start position:0% +different woman at the top of his list + + + align:start position:0% +different woman at the top of his list +because Angelina is gone + + align:start position:0% +because Angelina is gone + + + align:start position:0% +because Angelina is gone +forever okay this uh mating ritual + + align:start position:0% +forever okay this uh mating ritual + + + align:start position:0% +forever okay this uh mating ritual +continues until nothing changes and + + align:start position:0% +continues until nothing changes and + + + align:start position:0% +continues until nothing changes and +that's going to happen exactly when each + + align:start position:0% +that's going to happen exactly when each + + + align:start position:0% +that's going to happen exactly when each +girl has at most one Suitor cuz if she + + align:start position:0% +girl has at most one Suitor cuz if she + + + align:start position:0% +girl has at most one Suitor cuz if she +has more than one Suitor she's going to + + align:start position:0% +has more than one Suitor she's going to + + + align:start position:0% +has more than one Suitor she's going to +reject the less favorite ones so that is + + align:start position:0% +reject the less favorite ones so that is + + + align:start position:0% +reject the less favorite ones so that is +the definition of the stopping condition + + align:start position:0% +the definition of the stopping condition + + + align:start position:0% +the definition of the stopping condition +and on that day by definition no girl + + align:start position:0% +and on that day by definition no girl + + + align:start position:0% +and on that day by definition no girl +can have more than one Suitor so she + + align:start position:0% +can have more than one Suitor so she + + + align:start position:0% +can have more than one Suitor so she +will marry the one Suitor she has and + + align:start position:0% +will marry the one Suitor she has and + + + align:start position:0% +will marry the one Suitor she has and +that's the definition of the marriages + + align:start position:0% +that's the definition of the marriages + + + align:start position:0% +that's the definition of the marriages +that result if and when the mating + + align:start position:0% +that result if and when the mating + + + align:start position:0% +that result if and when the mating +ritual + + align:start position:0% +ritual + + + align:start position:0% +ritual +stops and we claim that they are going + + align:start position:0% +stops and we claim that they are going + + + align:start position:0% +stops and we claim that they are going +to be stable + + align:start position:0% +to be stable + + + align:start position:0% +to be stable +marriages now if we think about this + + align:start position:0% +marriages now if we think about this + + + align:start position:0% +marriages now if we think about this +process it's really a state machine in + + align:start position:0% +process it's really a state machine in + + + align:start position:0% +process it's really a state machine in +fact if you think about it what the + + align:start position:0% +fact if you think about it what the + + + align:start position:0% +fact if you think about it what the +states are is the is the set of girls on + + align:start position:0% +states are is the is the set of girls on + + + align:start position:0% +states are is the is the set of girls on +the boys list on any given morning and + + align:start position:0% +the boys list on any given morning and + + + align:start position:0% +the boys list on any given morning and +then uh those States evolve to a new + + align:start position:0% +then uh those States evolve to a new + + + align:start position:0% +then uh those States evolve to a new +list after the crossing out happens on + + align:start position:0% +list after the crossing out happens on + + + align:start position:0% +list after the crossing out happens on +the next morning so this is kind of a a + + align:start position:0% +the next morning so this is kind of a a + + + align:start position:0% +the next morning so this is kind of a a +memorable way to tell a story about the + + align:start position:0% +memorable way to tell a story about the + + + align:start position:0% +memorable way to tell a story about the +transitions of a state machine and we + + align:start position:0% +transitions of a state machine and we + + + align:start position:0% +transitions of a state machine and we +can bring our state machine Concepts to + + align:start position:0% +can bring our state machine Concepts to + + + align:start position:0% +can bring our state machine Concepts to +bear so the first thing we want to prove + + align:start position:0% +bear so the first thing we want to prove + + + align:start position:0% +bear so the first thing we want to prove +is that this state machine terminates + + align:start position:0% +is that this state machine terminates + + + align:start position:0% +is that this state machine terminates +that is to say there exists a wedding + + align:start position:0% +that is to say there exists a wedding + + + align:start position:0% +that is to say there exists a wedding +day um then we want to prove that this + + align:start position:0% +day um then we want to prove that this + + + align:start position:0% +day um then we want to prove that this +uh State machine is partially correct + + align:start position:0% +uh State machine is partially correct + + + align:start position:0% +uh State machine is partially correct +and what that means that uh when the + + align:start position:0% +and what that means that uh when the + + + align:start position:0% +and what that means that uh when the +machine stops everyone is married and + + align:start position:0% +machine stops everyone is married and + + + align:start position:0% +machine stops everyone is married and +that the marriages are stable so that's + + align:start position:0% +that the marriages are stable so that's + + + align:start position:0% +that the marriages are stable so that's +our task well termination easy because + + align:start position:0% +our task well termination easy because + + + align:start position:0% +our task well termination easy because +if you look at the state the state is + + align:start position:0% +if you look at the state the state is + + + align:start position:0% +if you look at the state the state is +the boys lists on a given morning and + + align:start position:0% +the boys lists on a given morning and + + + align:start position:0% +the boys lists on a given morning and +things evolve because boys get rejected + + align:start position:0% +things evolve because boys get rejected + + + align:start position:0% +things evolve because boys get rejected +and they cross girls off the list so + + align:start position:0% +and they cross girls off the list so + + + align:start position:0% +and they cross girls off the list so +what that means if we take the total + + align:start position:0% +what that means if we take the total + + + align:start position:0% +what that means if we take the total +number of names remaining on the boy + + align:start position:0% +number of names remaining on the boy + + + align:start position:0% +number of names remaining on the boy +lists On Any Given morning that is a + + align:start position:0% +lists On Any Given morning that is a + + + align:start position:0% +lists On Any Given morning that is a +strictly decreasing and non- negative + + align:start position:0% +strictly decreasing and non- negative + + + align:start position:0% +strictly decreasing and non- negative +integer valued variable so by the well- + + align:start position:0% +integer valued variable so by the well- + + + align:start position:0% +integer valued variable so by the well- +ordering principle that's strictly + + align:start position:0% +ordering principle that's strictly + + + align:start position:0% +ordering principle that's strictly +decreasing + + align:start position:0% +decreasing + + + align:start position:0% +decreasing +well-ordered um uh derive variable will + + align:start position:0% +well-ordered um uh derive variable will + + + align:start position:0% +well-ordered um uh derive variable will +reach a minimum value and by definition + + align:start position:0% +reach a minimum value and by definition + + + align:start position:0% +reach a minimum value and by definition +that's when the algorithm has to stop + + align:start position:0% +that's when the algorithm has to stop + + + align:start position:0% +that's when the algorithm has to stop +because it's strictly increasing so it + + align:start position:0% +because it's strictly increasing so it + + + align:start position:0% +because it's strictly increasing so it +can't move once it's reached its + + align:start position:0% +can't move once it's reached its + + + align:start position:0% +can't move once it's reached its +minimum so there's a wedding + + align:start position:0% +minimum so there's a wedding + + + align:start position:0% +minimum so there's a wedding +day all right so now let's examine + + align:start position:0% +day all right so now let's examine + + + align:start position:0% +day all right so now let's examine +correctness of this procedure and figure + + align:start position:0% +correctness of this procedure and figure + + + align:start position:0% +correctness of this procedure and figure +out what's supposed to happen on the + + align:start position:0% +out what's supposed to happen on the + + + align:start position:0% +out what's supposed to happen on the +wedding day we want to show that + + align:start position:0% +wedding day we want to show that + + + align:start position:0% +wedding day we want to show that +everybody's married and that the + + align:start position:0% +everybody's married and that the + + + align:start position:0% +everybody's married and that the +marriages are stable and in order to do + + align:start position:0% +marriages are stable and in order to do + + + align:start position:0% +marriages are stable and in order to do +that we're going to look at some more + + align:start position:0% +that we're going to look at some more + + + align:start position:0% +that we're going to look at some more +derive variables and an invariant that + + align:start position:0% +derive variables and an invariant that + + + align:start position:0% +derive variables and an invariant that +explains why the mating ritual works so + + align:start position:0% +explains why the mating ritual works so + + + align:start position:0% +explains why the mating ritual works so +the first remark is that the girls + + align:start position:0% +the first remark is that the girls + + + align:start position:0% +the first remark is that the girls +improve uh day by day or at least they + + align:start position:0% +improve uh day by day or at least they + + + align:start position:0% +improve uh day by day or at least they +don't get any worse namely a girl's + + align:start position:0% +don't get any worse namely a girl's + + + align:start position:0% +don't get any worse namely a girl's +favorite tomorrow will be at least as + + align:start position:0% +favorite tomorrow will be at least as + + + align:start position:0% +favorite tomorrow will be at least as +desirable to her as her favorite today + + align:start position:0% +desirable to her as her favorite today + + + align:start position:0% +desirable to her as her favorite today +that's for any given day if you look at + + align:start position:0% +that's for any given day if you look at + + + align:start position:0% +that's for any given day if you look at +a girl's favorite on this day and if + + align:start position:0% +a girl's favorite on this day and if + + + align:start position:0% +a girl's favorite on this day and if +there is a tomorrow then her favorite + + align:start position:0% +there is a tomorrow then her favorite + + + align:start position:0% +there is a tomorrow then her favorite +tomorrow is going to be at least as good + + align:start position:0% +tomorrow is going to be at least as good + + + align:start position:0% +tomorrow is going to be at least as good +as the one she has and why is that well + + align:start position:0% +as the one she has and why is that well + + + align:start position:0% +as the one she has and why is that well +because today's favorite will keep + + align:start position:0% +because today's favorite will keep + + + align:start position:0% +because today's favorite will keep +serenading her until he gets rejected + + align:start position:0% +serenading her until he gets rejected + + + align:start position:0% +serenading her until he gets rejected +and he only gets rejected when the girl + + align:start position:0% +and he only gets rejected when the girl + + + align:start position:0% +and he only gets rejected when the girl +that he's serenading gets yet a better + + align:start position:0% +that he's serenading gets yet a better + + + align:start position:0% +that he's serenading gets yet a better +Suitor and so the girls are always going + + align:start position:0% +Suitor and so the girls are always going + + + align:start position:0% +Suitor and so the girls are always going +to improve we could reformulate this uh + + align:start position:0% +to improve we could reformulate this uh + + + align:start position:0% +to improve we could reformulate this uh +in in state machine Language by saying + + align:start position:0% +in in state machine Language by saying + + + align:start position:0% +in in state machine Language by saying +that the rank of a girl's favorite where + + align:start position:0% +that the rank of a girl's favorite where + + + align:start position:0% +that the rank of a girl's favorite where +she uh rates the boy that's serting her + + align:start position:0% +she uh rates the boy that's serting her + + + align:start position:0% +she uh rates the boy that's serting her +on her own list of preferences is a + + align:start position:0% +on her own list of preferences is a + + + align:start position:0% +on her own list of preferences is a +weekly increasing variable it never gets + + align:start position:0% +weekly increasing variable it never gets + + + align:start position:0% +weekly increasing variable it never gets +any worse from one day to the + + align:start position:0% +any worse from one day to the + + + align:start position:0% +any worse from one day to the +next by the same reasoning or similar + + align:start position:0% +next by the same reasoning or similar + + + align:start position:0% +next by the same reasoning or similar +reasoning a boy's favorite uh tomorrow + + align:start position:0% +reasoning a boy's favorite uh tomorrow + + + align:start position:0% +reasoning a boy's favorite uh tomorrow +is going to be uh no better than today's + + align:start position:0% +is going to be uh no better than today's + + + align:start position:0% +is going to be uh no better than today's +it might be worse and so it's no more + + align:start position:0% +it might be worse and so it's no more + + + align:start position:0% +it might be worse and so it's no more +the woman that he going to say tomorrow + + align:start position:0% +the woman that he going to say tomorrow + + + align:start position:0% +the woman that he going to say tomorrow +is no more desirable to him than today + + align:start position:0% +is no more desirable to him than today + + + align:start position:0% +is no more desirable to him than today +is basically because he works straight + + align:start position:0% +is basically because he works straight + + + align:start position:0% +is basically because he works straight +down his list if he hasn't been rejected + + align:start position:0% +down his list if he hasn't been rejected + + + align:start position:0% +down his list if he hasn't been rejected +he'll keep Serena the same woman + + align:start position:0% +he'll keep Serena the same woman + + + align:start position:0% +he'll keep Serena the same woman +tomorrow if he has been rejected then uh + + align:start position:0% +tomorrow if he has been rejected then uh + + + align:start position:0% +tomorrow if he has been rejected then uh +he's got to be working on somebody lower + + align:start position:0% +he's got to be working on somebody lower + + + align:start position:0% +he's got to be working on somebody lower +on his list that's less desirable so + + align:start position:0% +on his list that's less desirable so + + + align:start position:0% +on his list that's less desirable so +again the rank of a girl on a boy that a + + align:start position:0% +again the rank of a girl on a boy that a + + + align:start position:0% +again the rank of a girl on a boy that a +boy serenades is a weekly decreasing + + align:start position:0% +boy serenades is a weekly decreasing + + + align:start position:0% +boy serenades is a weekly decreasing +deriv variable of this process and these + + align:start position:0% +deriv variable of this process and these + + + align:start position:0% +deriv variable of this process and these +observations lead us to an invariant + + align:start position:0% +observations lead us to an invariant + + + align:start position:0% +observations lead us to an invariant +that holds for the mating ritual and the + + align:start position:0% +that holds for the mating ritual and the + + + align:start position:0% +that holds for the mating ritual and the +invariant is that if you look at any + + align:start position:0% +invariant is that if you look at any + + + align:start position:0% +invariant is that if you look at any +girl G um and if there's a boy B and G + + align:start position:0% +girl G um and if there's a boy B and G + + + align:start position:0% +girl G um and if there's a boy B and G +is not on B's list that is g must have + + align:start position:0% +is not on B's list that is g must have + + + align:start position:0% +is not on B's list that is g must have +been crossed off by B at some point then + + align:start position:0% +been crossed off by B at some point then + + + align:start position:0% +been crossed off by B at some point then +uh the invariant is that the girl G has + + align:start position:0% +uh the invariant is that the girl G has + + + align:start position:0% +uh the invariant is that the girl G has +a favorite that is + + align:start position:0% +a favorite that is + + + align:start position:0% +a favorite that is +uh better than than b and the reason is + + align:start position:0% +uh better than than b and the reason is + + + align:start position:0% +uh better than than b and the reason is +that again when G rejected B she had a + + align:start position:0% +that again when G rejected B she had a + + + align:start position:0% +that again when G rejected B she had a +better Suitor than b and her suitors + + align:start position:0% +better Suitor than b and her suitors + + + align:start position:0% +better Suitor than b and her suitors +keep getting better by the uh weekly + + align:start position:0% +keep getting better by the uh weekly + + + align:start position:0% +keep getting better by the uh weekly +increasing property of her suitors and + + align:start position:0% +increasing property of her suitors and + + + align:start position:0% +increasing property of her suitors and +therefore uh she's going to have a + + align:start position:0% +therefore uh she's going to have a + + + align:start position:0% +therefore uh she's going to have a +Suitor that she likes at Le better than + + align:start position:0% +Suitor that she likes at Le better than + + + align:start position:0% +Suitor that she likes at Le better than +be whose list she's not on this holds + + align:start position:0% +be whose list she's not on this holds + + + align:start position:0% +be whose list she's not on this holds +for all G's and B's uh and that is an + + align:start position:0% +for all G's and B's uh and that is an + + + align:start position:0% +for all G's and B's uh and that is an +invariant from one day to the + + align:start position:0% +invariant from one day to the + + + align:start position:0% +invariant from one day to the +next so let's look at what happens on + + align:start position:0% +next so let's look at what happens on + + + align:start position:0% +next so let's look at what happens on +the wedding day and use the invariant to + + align:start position:0% +the wedding day and use the invariant to + + + align:start position:0% +the wedding day and use the invariant to +prove that everybody's married and that + + align:start position:0% +prove that everybody's married and that + + + align:start position:0% +prove that everybody's married and that +stability + + align:start position:0% +stability + + + align:start position:0% +stability +holds so the first remark is that each + + align:start position:0% +holds so the first remark is that each + + + align:start position:0% +holds so the first remark is that each +girl has at most one Suitor and we've + + align:start position:0% +girl has at most one Suitor and we've + + + align:start position:0% +girl has at most one Suitor and we've +observed that's by definition of a + + align:start position:0% +observed that's by definition of a + + + align:start position:0% +observed that's by definition of a +wedding day and now what we want to + + align:start position:0% +wedding day and now what we want to + + + align:start position:0% +wedding day and now what we want to +prove is that um uh each boy gets + + align:start position:0% +prove is that um uh each boy gets + + + align:start position:0% +prove is that um uh each boy gets +married well what's going on with a boy + + align:start position:0% +married well what's going on with a boy + + + align:start position:0% +married well what's going on with a boy +um a boy is either married because he's + + align:start position:0% +um a boy is either married because he's + + + align:start position:0% +um a boy is either married because he's +seraing the top woman on his list + + align:start position:0% +seraing the top woman on his list + + + align:start position:0% +seraing the top woman on his list +or maybe all the all the women on his + + align:start position:0% +or maybe all the all the women on his + + + align:start position:0% +or maybe all the all the women on his +List have been crossed off then he's not + + align:start position:0% +List have been crossed off then he's not + + + align:start position:0% +List have been crossed off then he's not +seren Serena anybody so that's the only + + align:start position:0% +seren Serena anybody so that's the only + + + align:start position:0% +seren Serena anybody so that's the only +way that he could be not married now the + + align:start position:0% +way that he could be not married now the + + + align:start position:0% +way that he could be not married now the +reason that this is the case is that + + align:start position:0% +reason that this is the case is that + + + align:start position:0% +reason that this is the case is that +there's no bigamy here so um boys + + align:start position:0% +there's no bigamy here so um boys + + + align:start position:0% +there's no bigamy here so um boys +serenate only one girl at a time so um + + align:start position:0% +serenate only one girl at a time so um + + + align:start position:0% +serenate only one girl at a time so um +if a boy uh is married there's only one + + align:start position:0% +if a boy uh is married there's only one + + + align:start position:0% +if a boy uh is married there's only one +possible woman that he can be married to + + align:start position:0% +possible woman that he can be married to + + + align:start position:0% +possible woman that he can be married to +and a woman's only married to one + + align:start position:0% +and a woman's only married to one + + + align:start position:0% +and a woman's only married to one +possible boy so let's now put these + + align:start position:0% +possible boy so let's now put these + + + align:start position:0% +possible boy so let's now put these +facts together and ARG AR that everybody + + align:start position:0% +facts together and ARG AR that everybody + + + align:start position:0% +facts together and ARG AR that everybody +is married on the wedding day and the + + align:start position:0% +is married on the wedding day and the + + + align:start position:0% +is married on the wedding day and the +proof is by + + align:start position:0% +proof is by + + + align:start position:0% +proof is by +contradiction suppose there's some boy + + align:start position:0% +contradiction suppose there's some boy + + + align:start position:0% +contradiction suppose there's some boy +be That's not married well that happens + + align:start position:0% +be That's not married well that happens + + + align:start position:0% +be That's not married well that happens +exactly when his list is empty otherwise + + align:start position:0% +exactly when his list is empty otherwise + + + align:start position:0% +exactly when his list is empty otherwise +he'd be serenading somebody and be + + align:start position:0% +he'd be serenading somebody and be + + + align:start position:0% +he'd be serenading somebody and be +married to her but if his list is empty + + align:start position:0% +married to her but if his list is empty + + + align:start position:0% +married to her but if his list is empty +by the invariant every girl has a a + + align:start position:0% +by the invariant every girl has a a + + + align:start position:0% +by the invariant every girl has a a +Suitor that she likes better than be + + align:start position:0% +Suitor that she likes better than be + + + align:start position:0% +Suitor that she likes better than be +which means she's going to be married to + + align:start position:0% +which means she's going to be married to + + + align:start position:0% +which means she's going to be married to +somebody that she likes better than be + + align:start position:0% +somebody that she likes better than be + + + align:start position:0% +somebody that she likes better than be +every girl's married but there are the + + align:start position:0% +every girl's married but there are the + + + align:start position:0% +every girl's married but there are the +same number of boys and girls so in fact + + align:start position:0% +same number of boys and girls so in fact + + + align:start position:0% +same number of boys and girls so in fact +given that there's no bigamy all the + + align:start position:0% +given that there's no bigamy all the + + + align:start position:0% +given that there's no bigamy all the +boys have to be married too and that + + align:start position:0% +boys have to be married too and that + + + align:start position:0% +boys have to be married too and that +settles that one so the next crucial + + align:start position:0% +settles that one so the next crucial + + + align:start position:0% +settles that one so the next crucial +property that we're interested in is + + align:start position:0% +property that we're interested in is + + + align:start position:0% +property that we're interested in is +stability that in fact this set of + + align:start position:0% +stability that in fact this set of + + + align:start position:0% +stability that in fact this set of +marriages which must come into being on + + align:start position:0% +marriages which must come into being on + + + align:start position:0% +marriages which must come into being on +the wedding day um are all stable and + + align:start position:0% +the wedding day um are all stable and + + + align:start position:0% +the wedding day um are all stable and +the argument for stability uh has two + + align:start position:0% +the argument for stability uh has two + + + align:start position:0% +the argument for stability uh has two +cases both of them trivial and that + + align:start position:0% +cases both of them trivial and that + + + align:start position:0% +cases both of them trivial and that +follow immediately from the invariant um + + align:start position:0% +follow immediately from the invariant um + + + align:start position:0% +follow immediately from the invariant um +first of all let's look at an arbitrary + + align:start position:0% +first of all let's look at an arbitrary + + + align:start position:0% +first of all let's look at an arbitrary +boy Bob uh I claim that won't be in a + + align:start position:0% +boy Bob uh I claim that won't be in a + + + align:start position:0% +boy Bob uh I claim that won't be in a +rogue couple with case one any girl G + + align:start position:0% +rogue couple with case one any girl G + + + align:start position:0% +rogue couple with case one any girl G +that's on his final list because if a + + align:start position:0% +that's on his final list because if a + + + align:start position:0% +that's on his final list because if a +girl is on his final list then uh he's + + align:start position:0% +girl is on his final list then uh he's + + + align:start position:0% +girl is on his final list then uh he's +already married to the best of them he + + align:start position:0% +already married to the best of them he + + + align:start position:0% +already married to the best of them he +marries the girl at the top of his list + + align:start position:0% +marries the girl at the top of his list + + + align:start position:0% +marries the girl at the top of his list +so he's not going to be tempted to + + align:start position:0% +so he's not going to be tempted to + + + align:start position:0% +so he's not going to be tempted to +switch uh to be part of a rogue couple + + align:start position:0% +switch uh to be part of a rogue couple + + + align:start position:0% +switch uh to be part of a rogue couple +with some girl that's uh still on his + + align:start position:0% +with some girl that's uh still on his + + + align:start position:0% +with some girl that's uh still on his +list case two is he's not going to be in + + align:start position:0% +list case two is he's not going to be in + + + align:start position:0% +list case two is he's not going to be in +a rogue couple with a girl that's not on + + align:start position:0% +a rogue couple with a girl that's not on + + + align:start position:0% +a rogue couple with a girl that's not on +his list Because by the invariant she's + + align:start position:0% +his list Because by the invariant she's + + + align:start position:0% +his list Because by the invariant she's +married to somebody she likes better + + align:start position:0% +married to somebody she likes better + + + align:start position:0% +married to somebody she likes better +than him so there's no available girl + + align:start position:0% +than him so there's no available girl + + + align:start position:0% +than him so there's no available girl +either way for Bob to be in a rogue + + align:start position:0% +either way for Bob to be in a rogue + + + align:start position:0% +either way for Bob to be in a rogue +couple with Bob of course is an + + align:start position:0% +couple with Bob of course is an + + + align:start position:0% +couple with Bob of course is an +arbitrary um uh boy and therefore no boy + + align:start position:0% +arbitrary um uh boy and therefore no boy + + + align:start position:0% +arbitrary um uh boy and therefore no boy +is in a rogue couple and indeed there + + align:start position:0% +is in a rogue couple and indeed there + + + align:start position:0% +is in a rogue couple and indeed there +are no roog couples \ No newline at end of file diff --git a/70auqrv84y8.txt b/70auqrv84y8.txt new file mode 100644 index 0000000000000000000000000000000000000000..a9d697bffb074c044e644e9f89f7aae9bbd62f7c --- /dev/null +++ b/70auqrv84y8.txt @@ -0,0 +1,274 @@ +What we'd like to do is to create a single +abstraction that can be used to address all + +our synchronization needs. + +In the early 1960's, the Dutch computer scientist +Edsger Dijkstra proposed a new abstract data + +type called the semaphore, which has an integer +value greater than or equal to 0. + +A programmer can declare a semaphore as shown +here, specifying its initial value. + +The semaphore lives in a memory location shared +by all the processes that need to synchronize + +their operation. + +The semaphore is accessed with two operations: +WAIT and SIGNAL. + +The WAIT operation will wait until the specified +semaphore has a value greater than 0, then + +it will decrement the semaphore value and +return to the calling program. + +If the semaphore value is 0 when WAIT is called, +conceptually execution is suspended until + +the semaphore value is non-zero. + +In a simple (inefficient) implementation, +the WAIT routine loops, periodically testing + +the value of the semaphore, proceeding when +its value is non-zero. + +The SIGNAL operation increments the value +of the specified semaphore. + +If there any processes WAITing on that semaphore, +exactly one of them may now proceed. + +We'll have to be careful with the implementation +of SIGNAL and WAIT to ensure that the "exactly + +one" constraint is satisfied, +i.e., that two processes both WAITing on the + +same semaphore won't both think they can decrement +it and proceed after a SIGNAL. + +A semaphore initialized with the value K guarantees +that the i_th call to SIGNAL will precede + +(i+K)_th call to WAIT. + +In a moment, we'll see some concrete examples +that will make this clear. + +Note that in 6.004, we're ruling out semaphores +with negative values. + +In the literature, you may see P(s) used in +place of WAIT(s) and V(s) used in place of + +SIGNAL(s). + +These operation names are derived from the +Dutch words for "test" and "increase". + +Let's see how to use semaphores to implement +precedence constraints. + +Here are two processes, each running a program +with 5 statements. + +Execution proceeds sequentially within each +process, so A1 executes before A2, and so + +on. + +But there are no constraints on the order +of execution between the processes, so statement + +B1 in Process B might be executed before or +after any of the statements in Process A. + +Even if A and B are running in a timeshared +environment on a single physical processor, + +execution may switch at any time between processes +A and B. + +Suppose we wish to impose the constraint that +the execution of statement A2 completes before + +execution of statement B4 begins. + +The red arrow shows the constraint we want. + +Here's the recipe for implementing this sort +of simple precedence constraint using semaphores. + +First, declare a semaphore (called "s" in +this example) and initialize its value to + +0. + +Place a call to signal(s) at the start of +the arrow. + +In this example, signal(s) is placed after +the statement A2 in process A. + +Then place a call to wait(s) at the end of +the arrow. + +In this example, wait(s) is placed before +the statement B4 in process B. + +With these modifications, process A executes +as before, with the signal to semaphore s + +happening after statement A2 is executed. + +Statements B1 through B3 also execute as before, +but when the wait(s) is executed, execution + +of process B is suspended until the signal(s) +statement has finished execution. + +This guarantees that execution of B4 will +start only after execution of A2 has completed. + +By initializing the semaphore s to 0, we enforced +the constraint that the first call to signal(s) + +had to complete before the first call to wait(s) +would succeed. + +Another way to think about semaphores is as +a management tool for a shared pool of K resources, + +where K is the initial value of the semaphore. + +You use the SIGNAL operation to add or return +resources to the shared pool. + +And you use the WAIT operation to allocate +a resource for your exclusive use. + +At any given time, the value of the semaphore +gives the number of unallocated resources + +still available in the shared pool. + +Note that the WAIT and SIGNAL operations can +be in the same process, or they may be in + +different processes, depending on when the +resource is allocated and returned. + +We can use semaphores to manage our N-character +FIFO buffer. + +Here we've defined a semaphore CHARS and initialized +it to 0. + +The value of CHARS will tell us how many characters +are in the buffer. + +So SEND does a signal(CHARS) after it has +added a character to the buffer, indicating + +the buffer now contains an additional character. + +And RCV does a wait(CHARS) to ensure the buffer +has at least one character before reading + +from the buffer. + +Since CHARS was initialized to 0, we've enforced +the constraint that the i_th call to signal(CHARS) + +precedes the completion of the i_th call to +wait(CHARS). + +In other words, RCV can't consume a character +until it has been placed in the buffer by + +SEND. + +Does this mean our producer and consumer are +now properly synchronized? + +Using the CHARS semaphore, we implemented +*one* of the two precedence constraints we + +identified as being necessary for correct +operation. + +Next we'll see how to implement the other +precedence constraint. + +What keeps the producer from putting more +than N characters into the N-character buffer? + +Nothing. + +Oops, the producer can start to overwrite +characters placed in the buffer earlier even + +though they haven't yet been read by the consumer. + +This is called buffer overflow and the sequence +of characters transmitted from producer to + +consumer becomes hopelessly corrupted. + +What we've guaranteed so far is that the consumer +can read a character only after the producer + +has placed it in the buffer, i.e., the consumer +can't read from an empty buffer. + +What we still need to guarantee is that the +producer can't get too far ahead of the consumer. + +Since the buffer holds at most N characters, +the producer can't send the (i+N)th character + +until the consumer has read the i_th character. + +Here we've added a second semaphore, SPACES, +to manage the number of spaces in the buffer. + +Initially the buffer is empty, so it has N +spaces. + +The producer must WAIT for a space to be available. + +When SPACES in non-zero, the WAIT succeeds, +decrementing the number of available spaces + +by one and then the producer fills that space +with the next character. + +The consumer signals the availability of another +space after it reads a character from the + +buffer. + +There's a nice symmetry here. + +The producer consumes spaces and produces +characters. + +The consumer consumes characters and produces +spaces. + +Semaphores are used to track the availability +of both resources (i.e., characters and spaces), + +synchronizing the execution of the producer +and consumer. + +This works great when there is a single producer +process and a single consumer process. + +Next we'll think about what will happen if +we have multiple producers and multiple consumers. \ No newline at end of file diff --git a/7Y5me3mwXpA.txt b/7Y5me3mwXpA.txt new file mode 100644 index 0000000000000000000000000000000000000000..173544f3b6bdaf6ce04bd680867c30fba6b2dcdd --- /dev/null +++ b/7Y5me3mwXpA.txt @@ -0,0 +1,2419 @@ +align:start position:0% + +today we continue with our discussion of + + align:start position:0% +today we continue with our discussion of + + + align:start position:0% +today we continue with our discussion of +wkb so a few matters regarding wkb were + + align:start position:0% +wkb so a few matters regarding wkb were + + + align:start position:0% +wkb so a few matters regarding wkb were +explained in the last few segments we + + align:start position:0% +explained in the last few segments we + + + align:start position:0% +explained in the last few segments we +discussed that there would be a useful + + align:start position:0% +discussed that there would be a useful + + + align:start position:0% +discussed that there would be a useful +to define a position dependent momentum + + align:start position:0% +to define a position dependent momentum + + + align:start position:0% +to define a position dependent momentum +for a particle that is moving in a + + align:start position:0% +for a particle that is moving in a + + + align:start position:0% +for a particle that is moving in a +potential that was a completely + + align:start position:0% +potential that was a completely + + + align:start position:0% +potential that was a completely +classical notion but helped our + + align:start position:0% +classical notion but helped our + + + align:start position:0% +classical notion but helped our +terminology in solving the Schrodinger + + align:start position:0% +terminology in solving the Schrodinger + + + align:start position:0% +terminology in solving the Schrodinger +equation and set up the stage for some + + align:start position:0% +equation and set up the stage for some + + + align:start position:0% +equation and set up the stage for some +definitions for example a position + + align:start position:0% +definitions for example a position + + + align:start position:0% +definitions for example a position +dependent the Broglie wavelength that + + align:start position:0% +dependent the Broglie wavelength that + + + align:start position:0% +dependent the Broglie wavelength that +would be given by in terms of the + + align:start position:0% +would be given by in terms of the + + + align:start position:0% +would be given by in terms of the +position dependent momentum by the + + align:start position:0% +position dependent momentum by the + + + align:start position:0% +position dependent momentum by the +classic formula that they broadly use + + align:start position:0% +classic formula that they broadly use + + + align:start position:0% +classic formula that they broadly use +for particles that move with constant + + align:start position:0% +for particles that move with constant + + + align:start position:0% +for particles that move with constant +momentum then in this language the + + align:start position:0% +momentum then in this language the + + + align:start position:0% +momentum then in this language the +Schrodinger equation took the form of + + align:start position:0% +Schrodinger equation took the form of + + + align:start position:0% +Schrodinger equation took the form of +equation the time independent + + align:start position:0% +equation the time independent + + + align:start position:0% +equation the time independent +Schrodinger equation to the form P + + align:start position:0% +Schrodinger equation to the form P + + + align:start position:0% +Schrodinger equation to the form P +squared on sy is equal to P squared of x + + align:start position:0% +squared on sy is equal to P squared of x + + + align:start position:0% +squared on sy is equal to P squared of x +times Phi this is Phi of X and we + + align:start position:0% +times Phi this is Phi of X and we + + + align:start position:0% +times Phi this is Phi of X and we +mentioned that was kind of nice that the + + align:start position:0% +mentioned that was kind of nice that the + + + align:start position:0% +mentioned that was kind of nice that the +momentum operator ended up having sort + + align:start position:0% +momentum operator ended up having sort + + + align:start position:0% +momentum operator ended up having sort +of in the style of an eigenvalue vagin + + align:start position:0% +of in the style of an eigenvalue vagin + + + align:start position:0% +of in the style of an eigenvalue vagin +value P of X we then spoke about wave + + align:start position:0% +value P of X we then spoke about wave + + + align:start position:0% +value P of X we then spoke about wave +functions that in the wkb approximation + + align:start position:0% +functions that in the wkb approximation + + + align:start position:0% +functions that in the wkb approximation +would take form of an exponential with a + + align:start position:0% +would take form of an exponential with a + + + align:start position:0% +would take form of an exponential with a +face and a magnitude so the usual + + align:start position:0% +face and a magnitude so the usual + + + align:start position:0% +face and a magnitude so the usual +notation we have for complex numbers so + + align:start position:0% +notation we have for complex numbers so + + + align:start position:0% +notation we have for complex numbers so +the PSI of X and T would be written as + + align:start position:0% +the PSI of X and T would be written as + + + align:start position:0% +the PSI of X and T would be written as +Rho of X and T e to the I over H bar s + + align:start position:0% +Rho of X and T e to the I over H bar s + + + align:start position:0% +Rho of X and T e to the I over H bar s +of X and T + + align:start position:0% + + + + align:start position:0% + +that's a typical form of a wkb + + align:start position:0% +that's a typical form of a wkb + + + align:start position:0% +that's a typical form of a wkb +wavefunction adieu we'll see soon and + + align:start position:0% +wavefunction adieu we'll see soon and + + + align:start position:0% +wavefunction adieu we'll see soon and +for such wave functions it's kind of + + align:start position:0% +for such wave functions it's kind of + + + align:start position:0% +for such wave functions it's kind of +manifest that row here is the charge + + align:start position:0% +manifest that row here is the charge + + + align:start position:0% +manifest that row here is the charge +density because if you think the norm + + align:start position:0% +density because if you think the norm + + + align:start position:0% +density because if you think the norm +squared of sy that gives you exactly ro + + align:start position:0% +squared of sy that gives you exactly ro + + + align:start position:0% +squared of sy that gives you exactly ro +the face cancels on the other hand the + + align:start position:0% +the face cancels on the other hand the + + + align:start position:0% +the face cancels on the other hand the +computation of the current was a little + + align:start position:0% +computation of the current was a little + + + align:start position:0% +computation of the current was a little +more interesting and they gave you Rho + + align:start position:0% +more interesting and they gave you Rho + + + align:start position:0% +more interesting and they gave you Rho +times gradient of s over m the mass of + + align:start position:0% +times gradient of s over m the mass of + + + align:start position:0% +times gradient of s over m the mass of +the particle so we identified the + + align:start position:0% +the particle so we identified the + + + align:start position:0% +the particle so we identified the +current as perpendicular to the surfaces + + align:start position:0% +current as perpendicular to the surfaces + + + align:start position:0% +current as perpendicular to the surfaces +of constant s or constant face in the + + align:start position:0% +of constant s or constant face in the + + + align:start position:0% +of constant s or constant face in the +exponent of the wkb equation our last + + align:start position:0% +exponent of the wkb equation our last + + + align:start position:0% +exponent of the wkb equation our last +comments had to do with lambda and we've + + align:start position:0% +comments had to do with lambda and we've + + + align:start position:0% +comments had to do with lambda and we've +said that we suspect that the semi + + align:start position:0% +said that we suspect that the semi + + + align:start position:0% +said that we suspect that the semi +classical approximation is valid in some + + align:start position:0% +classical approximation is valid in some + + + align:start position:0% +classical approximation is valid in some +way when lambda is small compared to + + align:start position:0% +way when lambda is small compared to + + + align:start position:0% +way when lambda is small compared to +physical length of a system or for + + align:start position:0% +physical length of a system or for + + + align:start position:0% +physical length of a system or for +lambda changes slowly as a function of + + align:start position:0% +lambda changes slowly as a function of + + + align:start position:0% +lambda changes slowly as a function of +position and those things we have not + + align:start position:0% +position and those things we have not + + + align:start position:0% +position and those things we have not +quite yet determined precisely how they + + align:start position:0% +quite yet determined precisely how they + + + align:start position:0% +quite yet determined precisely how they +go and some of what we have to do today + + align:start position:0% +go and some of what we have to do today + + + align:start position:0% +go and some of what we have to do today +is understand more concretely the nature + + align:start position:0% +is understand more concretely the nature + + + align:start position:0% +is understand more concretely the nature +of the approximation so the + + align:start position:0% +of the approximation so the + + + align:start position:0% +of the approximation so the +semi-classical approximation has + + align:start position:0% +semi-classical approximation has + + + align:start position:0% +semi-classical approximation has +something to do with lambda slowly + + align:start position:0% +something to do with lambda slowly + + + align:start position:0% +something to do with lambda slowly +varying varying and with lambda small in + + align:start position:0% +varying varying and with lambda small in + + + align:start position:0% +varying varying and with lambda small in +some sense and since you have an H bar + + align:start position:0% +some sense and since you have an H bar + + + align:start position:0% +some sense and since you have an H bar +in here that would make it small if H + + align:start position:0% +in here that would make it small if H + + + align:start position:0% +in here that would make it small if H +bar is small we also mentioned we would + + align:start position:0% +bar is small we also mentioned we would + + + align:start position:0% +bar is small we also mentioned we would +end up considering the limit as a sort + + align:start position:0% +end up considering the limit as a sort + + + align:start position:0% +end up considering the limit as a sort +of imaginary + + align:start position:0% +of imaginary + + + align:start position:0% +of imaginary +or fictitious limit in which h bar goes + + align:start position:0% +or fictitious limit in which h bar goes + + + align:start position:0% +or fictitious limit in which h bar goes +to zero so it's time to try to really do + + align:start position:0% +to zero so it's time to try to really do + + + align:start position:0% +to zero so it's time to try to really do +the approximation let let's try to write + + align:start position:0% +the approximation let let's try to write + + + align:start position:0% +the approximation let let's try to write +something and approximate the solution + + align:start position:0% +something and approximate the solution + + + align:start position:0% +something and approximate the solution +now we had a nice instructive form of + + align:start position:0% +now we had a nice instructive form of + + + align:start position:0% +now we had a nice instructive form of +the wavefunction there but I will take a + + align:start position:0% +the wavefunction there but I will take a + + + align:start position:0% +the wavefunction there but I will take a +simpler form in which the wave function + + align:start position:0% +simpler form in which the wave function + + + align:start position:0% +simpler form in which the wave function +will be just a pure exponential so + + align:start position:0% +will be just a pure exponential so + + + align:start position:0% +will be just a pure exponential so +setting the approximation scheme so + + align:start position:0% +setting the approximation scheme so + + + align:start position:0% +setting the approximation scheme so +approximation scheme so before I had the + + align:start position:0% +approximation scheme so before I had the + + + align:start position:0% +approximation scheme so before I had the +wave function that had a norm and a face + + align:start position:0% +wave function that had a norm and a face + + + align:start position:0% +wave function that had a norm and a face +now I want a wave function that looks + + align:start position:0% +now I want a wave function that looks + + + align:start position:0% +now I want a wave function that looks +like it just has a face you would say of + + align:start position:0% +like it just has a face you would say of + + + align:start position:0% +like it just has a face you would say of +course that's impossible so we will use + + align:start position:0% +course that's impossible so we will use + + + align:start position:0% +course that's impossible so we will use +for all for the time independent + + align:start position:0% +for all for the time independent + + + align:start position:0% +for all for the time independent +Schrodinger equation so we will use an S + + align:start position:0% +Schrodinger equation so we will use an S + + + align:start position:0% +Schrodinger equation so we will use an S +of X and we will write up side effects + + align:start position:0% +of X and we will write up side effects + + + align:start position:0% +of X and we will write up side effects +in the firm e to the I H bar s of X and + + align:start position:0% +in the firm e to the I H bar s of X and + + + align:start position:0% +in the firm e to the I H bar s of X and +you say no that's not true my usual wave + + align:start position:0% +you say no that's not true my usual wave + + + align:start position:0% +you say no that's not true my usual wave +functions are more than just faces are + + align:start position:0% +functions are more than just faces are + + + align:start position:0% +functions are more than just faces are +not just faces we've seen wave functions + + align:start position:0% +not just faces we've seen wave functions + + + align:start position:0% +not just faces we've seen wave functions +of different magnitude here that wave + + align:start position:0% +of different magnitude here that wave + + + align:start position:0% +of different magnitude here that wave +function would have always density equal + + align:start position:0% +function would have always density equal + + + align:start position:0% +function would have always density equal +to one but that is avoided that + + align:start position:0% + + + + align:start position:0% + +criticism is voided if you just simply + + align:start position:0% +criticism is voided if you just simply + + + align:start position:0% +criticism is voided if you just simply +say that s now may be a complex number + + align:start position:0% +say that s now may be a complex number + + + align:start position:0% +say that s now may be a complex number +so if s is itself a complex number the + + align:start position:0% +so if s is itself a complex number the + + + align:start position:0% +so if s is itself a complex number the +imaginary part of s provides the norm of + + align:start position:0% +imaginary part of s provides the norm of + + + align:start position:0% +imaginary part of s provides the norm of +the wave function so it's possible to do + + align:start position:0% +the wave function so it's possible to do + + + align:start position:0% +the wave function so it's possible to do +that any function can move any row up + + align:start position:0% +that any function can move any row up + + + align:start position:0% +that any function can move any row up +here + + align:start position:0% +here + + + align:start position:0% +here +can be written as the exponential of the + + align:start position:0% +can be written as the exponential of the + + + align:start position:0% +can be written as the exponential of the +log of something and then can be brought + + align:start position:0% +log of something and then can be brought + + + align:start position:0% +log of something and then can be brought +in the exponent and there's no loss of + + align:start position:0% +in the exponent and there's no loss of + + + align:start position:0% +in the exponent and there's no loss of +generality in writing something like + + align:start position:0% +generality in writing something like + + + align:start position:0% +generality in writing something like +that if s is complex now we have the + + align:start position:0% +that if s is complex now we have the + + + align:start position:0% +that if s is complex now we have the +Schrodinger equation and the sheraton + + align:start position:0% +Schrodinger equation and the sheraton + + + align:start position:0% +Schrodinger equation and the sheraton +equation was written there so it's minus + + align:start position:0% +equation was written there so it's minus + + + align:start position:0% +equation was written there so it's minus +H squared ii the x squared of Phi of X + + align:start position:0% + + + + align:start position:0% + +is equal to P squared of X e to the I + + align:start position:0% +is equal to P squared of X e to the I + + + align:start position:0% +is equal to P squared of X e to the I +over H bar s now when we differentiate + + align:start position:0% +over H bar s now when we differentiate + + + align:start position:0% +over H bar s now when we differentiate +an exponential we differentiate it two + + align:start position:0% +an exponential we differentiate it two + + + align:start position:0% +an exponential we differentiate it two +times we will have a couple of things we + + align:start position:0% +times we will have a couple of things we + + + align:start position:0% +times we will have a couple of things we +can differentiate the first time Brinson + + align:start position:0% +can differentiate the first time Brinson + + + align:start position:0% +can differentiate the first time Brinson +s prime down and the second time you can + + align:start position:0% +s prime down and the second time you can + + + align:start position:0% +s prime down and the second time you can +differentiate the exponential you can + + align:start position:0% +differentiate the exponential you can + + + align:start position:0% +differentiate the exponential you can +differentiate what is down already so + + align:start position:0% +differentiate what is down already so + + + align:start position:0% +differentiate what is down already so +it's two terms the first one would be + + align:start position:0% +it's two terms the first one would be + + + align:start position:0% +it's two terms the first one would be +imagine differentiating the first one s + + align:start position:0% +imagine differentiating the first one s + + + align:start position:0% +imagine differentiating the first one s +goes down and then the derivative acts + + align:start position:0% +goes down and then the derivative acts + + + align:start position:0% +goes down and then the derivative acts +on the S so you get I over H bar s + + align:start position:0% +on the S so you get I over H bar s + + + align:start position:0% +on the S so you get I over H bar s +double prime which is prime notation and + + align:start position:0% +double prime which is prime notation and + + + align:start position:0% +double prime which is prime notation and +the other one is when you differentiate + + align:start position:0% +the other one is when you differentiate + + + align:start position:0% +the other one is when you differentiate +once here it brings a factor down again + + align:start position:0% +once here it brings a factor down again + + + align:start position:0% +once here it brings a factor down again +there so it's plus I over H bar s prime + + align:start position:0% +there so it's plus I over H bar s prime + + + align:start position:0% +there so it's plus I over H bar s prime +squared and then the face is still there + + align:start position:0% +squared and then the face is still there + + + align:start position:0% +squared and then the face is still there +and it can cancel between the left and + + align:start position:0% +and it can cancel between the left and + + + align:start position:0% +and it can cancel between the left and +the right so this is equal to P squared + + align:start position:0% +the right so this is equal to P squared + + + align:start position:0% +the right so this is equal to P squared +of X + + align:start position:0% + + + + align:start position:0% + +so I took the derivative and canceled + + align:start position:0% +so I took the derivative and canceled + + + align:start position:0% +so I took the derivative and canceled +the Exponential's so cleaning this up a + + align:start position:0% +the Exponential's so cleaning this up a + + + align:start position:0% +the Exponential's so cleaning this up a +little bit will have this term over here + + align:start position:0% +little bit will have this term over here + + + align:start position:0% +little bit will have this term over here +that the ages cancel the sign cancels + + align:start position:0% +that the ages cancel the sign cancels + + + align:start position:0% +that the ages cancel the sign cancels +and you get s prime of x squared minus I + + align:start position:0% +and you get s prime of x squared minus I + + + align:start position:0% +and you get s prime of x squared minus I +h-bar is double prime is equal to P + + align:start position:0% +h-bar is double prime is equal to P + + + align:start position:0% +h-bar is double prime is equal to P +squared of X okay simple enough we have + + align:start position:0% +squared of X okay simple enough we have + + + align:start position:0% +squared of X okay simple enough we have +a derivation of that equation and the + + align:start position:0% +a derivation of that equation and the + + + align:start position:0% +a derivation of that equation and the +first thing that you say is it looks + + align:start position:0% +first thing that you say is it looks + + + align:start position:0% +first thing that you say is it looks +like we've gone backwards we've gone + + align:start position:0% +like we've gone backwards we've gone + + + align:start position:0% +like we've gone backwards we've gone +from our reasonably simple equation + + align:start position:0% +from our reasonably simple equation + + + align:start position:0% +from our reasonably simple equation +destroying our equation second order + + align:start position:0% +destroying our equation second order + + + align:start position:0% +destroying our equation second order +linear differential equation to a + + align:start position:0% +linear differential equation to a + + + align:start position:0% +linear differential equation to a +nonlinear equation here is the function + + align:start position:0% +nonlinear equation here is the function + + + align:start position:0% +nonlinear equation here is the function +squared the derivative square second + + align:start position:0% +squared the derivative square second + + + align:start position:0% +squared the derivative square second +derivative no fun is nothing linear + + align:start position:0% +derivative no fun is nothing linear + + + align:start position:0% +derivative no fun is nothing linear +about this equation in s if you have one + + align:start position:0% +about this equation in s if you have one + + + align:start position:0% +about this equation in s if you have one +solution for an S and another solution + + align:start position:0% +solution for an S and another solution + + + align:start position:0% +solution for an S and another solution +you cannot add them so this happens + + align:start position:0% +you cannot add them so this happens + + + align:start position:0% +you cannot add them so this happens +because we put everything in the + + align:start position:0% +because we put everything in the + + + align:start position:0% +because we put everything in the +exponential when you think double + + align:start position:0% +exponential when you think double + + + align:start position:0% +exponential when you think double +derivatives of an exponential you get a + + align:start position:0% +derivatives of an exponential you get a + + + align:start position:0% +derivatives of an exponential you get a +term with double derivatives in a term + + align:start position:0% +term with double derivatives in a term + + + align:start position:0% +term with double derivatives in a term +with a derivative squared there's + + align:start position:0% +with a derivative squared there's + + + align:start position:0% +with a derivative squared there's +nothing you can do and this still + + align:start position:0% +nothing you can do and this still + + + align:start position:0% +nothing you can do and this still +represents progress in some way even + + align:start position:0% +represents progress in some way even + + + align:start position:0% +represents progress in some way even +though it has become an equation that + + align:start position:0% +though it has become an equation that + + + align:start position:0% +though it has become an equation that +looks more difficult it can be tracted + + align:start position:0% +looks more difficult it can be tracted + + + align:start position:0% +looks more difficult it can be tracted +in some other way so the first and most + + align:start position:0% +in some other way so the first and most + + + align:start position:0% +in some other way so the first and most +important thing we want to say about + + align:start position:0% +important thing we want to say about + + + align:start position:0% +important thing we want to say about +this equation is that it's nonlinear + + align:start position:0% + + + + align:start position:0% + +differential equation the h-bar term + + align:start position:0% +differential equation the h-bar term + + + align:start position:0% +differential equation the h-bar term +appears in just one position here and + + align:start position:0% +appears in just one position here and + + + align:start position:0% +appears in just one position here and +let's consider a following claim I will + + align:start position:0% +let's consider a following claim I will + + + align:start position:0% +let's consider a following claim I will +claim that I h-bar s double prime this + + align:start position:0% +claim that I h-bar s double prime this + + + align:start position:0% +claim that I h-bar s double prime this +term is small when V of X is slowly + + align:start position:0% +term is small when V of X is slowly + + + align:start position:0% +term is small when V of X is slowly +varying you see we're having in mind the + + align:start position:0% +varying you see we're having in mind the + + + align:start position:0% +varying you see we're having in mind the +situation with which a particle is + + align:start position:0% +situation with which a particle is + + + align:start position:0% +situation with which a particle is +moving in a potential a quantum particle + + align:start position:0% +moving in a potential a quantum particle + + + align:start position:0% +moving in a potential a quantum particle +so there it is P of X is well-defined + + align:start position:0% +so there it is P of X is well-defined + + + align:start position:0% +so there it is P of X is well-defined +that's the term that goes into this + + align:start position:0% +that's the term that goes into this + + + align:start position:0% +that's the term that goes into this +equation so this is partly known you may + + align:start position:0% +equation so this is partly known you may + + + align:start position:0% +equation so this is partly known you may +not know the energy but the potential + + align:start position:0% +not know the energy but the potential + + + align:start position:0% +not know the energy but the potential +you know and my claim and perhaps a very + + align:start position:0% +you know and my claim and perhaps a very + + + align:start position:0% +you know and my claim and perhaps a very +important claim about this equation that + + align:start position:0% +important claim about this equation that + + + align:start position:0% +important claim about this equation that +sets you going clearly is that when V of + + align:start position:0% +sets you going clearly is that when V of + + + align:start position:0% +sets you going clearly is that when V of +s is slowly varying this term is almost + + align:start position:0% +s is slowly varying this term is almost + + + align:start position:0% +s is slowly varying this term is almost +irrelevant okay that's the first thing + + align:start position:0% +irrelevant okay that's the first thing + + + align:start position:0% +irrelevant okay that's the first thing +we want to make sure we understand so + + align:start position:0% + + + + align:start position:0% + +let's assume indeed let's take V of X is + + align:start position:0% +let's assume indeed let's take V of X is + + + align:start position:0% +let's assume indeed let's take V of X is +equal to v-0 a constant so this is the + + align:start position:0% +equal to v-0 a constant so this is the + + + align:start position:0% +equal to v-0 a constant so this is the +extreme case of a slowly varying + + align:start position:0% +extreme case of a slowly varying + + + align:start position:0% +extreme case of a slowly varying +potential but just doesn't vary at all + + align:start position:0% +potential but just doesn't vary at all + + + align:start position:0% +potential but just doesn't vary at all +in that case P of X is going to be a + + align:start position:0% +in that case P of X is going to be a + + + align:start position:0% +in that case P of X is going to be a +constant and that constant is square + + align:start position:0% +constant and that constant is square + + + align:start position:0% +constant and that constant is square +root of 2m e minus V not + + align:start position:0% + + + + align:start position:0% + +and what do we have here we have a free + + align:start position:0% +and what do we have here we have a free + + + align:start position:0% +and what do we have here we have a free +particle this V of X is a constant so + + align:start position:0% +particle this V of X is a constant so + + + align:start position:0% +particle this V of X is a constant so +the solution of the Schrodinger equation + + align:start position:0% +the solution of the Schrodinger equation + + + align:start position:0% +the solution of the Schrodinger equation +that you know in general is that sigh of + + align:start position:0% +that you know in general is that sigh of + + + align:start position:0% +that you know in general is that sigh of +X is e to the I P naught X over H bar + + align:start position:0% +X is e to the I P naught X over H bar + + + align:start position:0% +X is e to the I P naught X over H bar +that solves the Schrodinger equation now + + align:start position:0% +that solves the Schrodinger equation now + + + align:start position:0% +that solves the Schrodinger equation now +we were talking about this equation so + + align:start position:0% +we were talking about this equation so + + + align:start position:0% +we were talking about this equation so +to connect to that equation in this + + align:start position:0% +to connect to that equation in this + + + align:start position:0% +to connect to that equation in this +situation of constant potential constant + + align:start position:0% +situation of constant potential constant + + + align:start position:0% +situation of constant potential constant +momentum in the classical sense and free + + align:start position:0% +momentum in the classical sense and free + + + align:start position:0% +momentum in the classical sense and free +particle with that constant momentum + + align:start position:0% +particle with that constant momentum + + + align:start position:0% +particle with that constant momentum +remember that s is the term here in the + + align:start position:0% +remember that s is the term here in the + + + align:start position:0% +remember that s is the term here in the +exponential so for this solution here s + + align:start position:0% +exponential so for this solution here s + + + align:start position:0% +exponential so for this solution here s +of X is equal to p0 X that's all it is + + align:start position:0% +of X is equal to p0 X that's all it is + + + align:start position:0% +of X is equal to p0 X that's all it is +it's whatever is left when you single + + align:start position:0% +it's whatever is left when you single + + + align:start position:0% +it's whatever is left when you single +out the I over H bar and let's look at + + align:start position:0% +out the I over H bar and let's look at + + + align:start position:0% +out the I over H bar and let's look at +that thing that should be a solution you + + align:start position:0% +that thing that should be a solution you + + + align:start position:0% +that thing that should be a solution you +see we've constructed the solution of + + align:start position:0% +see we've constructed the solution of + + + align:start position:0% +see we've constructed the solution of +the Schrodinger equation for constant + + align:start position:0% +the Schrodinger equation for constant + + + align:start position:0% +the Schrodinger equation for constant +potential we've read what s of X is that + + align:start position:0% +potential we've read what s of X is that + + + align:start position:0% +potential we've read what s of X is that +should solve this equation and how does + + align:start position:0% +should solve this equation and how does + + + align:start position:0% +should solve this equation and how does +it manage to solve it it manages to + + align:start position:0% +it manage to solve it it manages to + + + align:start position:0% +it manage to solve it it manages to +solve it because s prime of X then s + + align:start position:0% +solve it because s prime of X then s + + + align:start position:0% +solve it because s prime of X then s +prime of X is equal to P naught s double + + align:start position:0% +prime of X is equal to P naught s double + + + align:start position:0% +prime of X is equal to P naught s double +prime of X is equal to 0 and the + + align:start position:0% +prime of X is equal to 0 and the + + + align:start position:0% +prime of X is equal to 0 and the +equation works out with the first term + + align:start position:0% +equation works out with the first term + + + align:start position:0% +equation works out with the first term +squared P naught squared equal to P of x + + align:start position:0% +squared P naught squared equal to P of x + + + align:start position:0% +squared P naught squared equal to P of x +squared which is P naught squared so + + align:start position:0% +squared which is P naught squared so + + + align:start position:0% +squared which is P naught squared so +this term first term in the left hand + + align:start position:0% +this term first term in the left hand + + + align:start position:0% +this term first term in the left hand +side is equal to the right hand side + + align:start position:0% +side is equal to the right hand side + + + align:start position:0% +side is equal to the right hand side +this term is identically 0 so when the + + align:start position:0% +this term is identically 0 so when the + + + align:start position:0% +this term is identically 0 so when the +potential is constant that term IH bar s + + align:start position:0% +potential is constant that term IH bar s + + + align:start position:0% +potential is constant that term IH bar s +double prime plays no role it's 0 + + align:start position:0% +double prime plays no role it's 0 + + + align:start position:0% +double prime plays no role it's 0 +so when so the term I h-bar s double + + align:start position:0% +so when so the term I h-bar s double + + + align:start position:0% +so when so the term I h-bar s double +prime is equal to zero so the claim now + + align:start position:0% +prime is equal to zero so the claim now + + + align:start position:0% +prime is equal to zero so the claim now +follows from fairly intuitive result if + + align:start position:0% +follows from fairly intuitive result if + + + align:start position:0% +follows from fairly intuitive result if +the potential is constant that term in + + align:start position:0% +the potential is constant that term in + + + align:start position:0% +the potential is constant that term in +the solution is zero if the potential + + align:start position:0% +the solution is zero if the potential + + + align:start position:0% +the solution is zero if the potential +will be extremely slowly varying that + + align:start position:0% +will be extremely slowly varying that + + + align:start position:0% +will be extremely slowly varying that +term should be very small you know you + + align:start position:0% +term should be very small you know you + + + align:start position:0% +term should be very small you know you +cannot expect that the constant + + align:start position:0% +cannot expect that the constant + + + align:start position:0% +cannot expect that the constant +potential has a solution and you doubt + + align:start position:0% +potential has a solution and you doubt + + + align:start position:0% +potential has a solution and you doubt +infinitesimal variation of your + + align:start position:0% +infinitesimal variation of your + + + align:start position:0% +infinitesimal variation of your +potential and suddenly this term becomes + + align:start position:0% +potential and suddenly this term becomes + + + align:start position:0% +potential and suddenly this term becomes +very big so for constant V I H bar s + + align:start position:0% +very big so for constant V I H bar s + + + align:start position:0% +very big so for constant V I H bar s +double prime equal zero so for four + + align:start position:0% +double prime equal zero so for four + + + align:start position:0% +double prime equal zero so for four +slowly varying V of X I H bar of s + + align:start position:0% +slowly varying V of X I H bar of s + + + align:start position:0% +slowly varying V of X I H bar of s +double prime should be small in the + + align:start position:0% +double prime should be small in the + + + align:start position:0% +double prime should be small in the +sense that this solution is + + align:start position:0% +sense that this solution is + + + align:start position:0% +sense that this solution is +approximately correct so if we do say + + align:start position:0% +approximately correct so if we do say + + + align:start position:0% +approximately correct so if we do say +that we've identified the term in the + + align:start position:0% +that we've identified the term in the + + + align:start position:0% +that we've identified the term in the +equation that is small when potentials + + align:start position:0% +equation that is small when potentials + + + align:start position:0% +equation that is small when potentials +are slowly vary therefore we will take + + align:start position:0% +are slowly vary therefore we will take + + + align:start position:0% +are slowly vary therefore we will take +that term as being the small term in + + align:start position:0% +that term as being the small term in + + + align:start position:0% +that term as being the small term in +that equation and this will be nicely + + align:start position:0% +that equation and this will be nicely + + + align:start position:0% +that equation and this will be nicely +implemented by considering as we said H + + align:start position:0% +implemented by considering as we said H + + + align:start position:0% +implemented by considering as we said H +bar going to 0 or H as a small parameter + + align:start position:0% + + + + align:start position:0% + +we will learn as we do the approximation + + align:start position:0% + + + + align:start position:0% + +how to quantify what something that we + + align:start position:0% +how to quantify what something that we + + + align:start position:0% +how to quantify what something that we +call slowly varying is but we will take + + align:start position:0% +call slowly varying is but we will take + + + align:start position:0% +call slowly varying is but we will take +H now as a small parameter + + align:start position:0% +H now as a small parameter + + + align:start position:0% +H now as a small parameter +that makes that term small and set up an + + align:start position:0% +that makes that term small and set up an + + + align:start position:0% +that makes that term small and set up an +expansion to solve this equation that is + + align:start position:0% +expansion to solve this equation that is + + + align:start position:0% +expansion to solve this equation that is +our goal now so how do we set it up we + + align:start position:0% +our goal now so how do we set it up we + + + align:start position:0% +our goal now so how do we set it up we +set up like this we say as effects as + + align:start position:0% +set up like this we say as effects as + + + align:start position:0% +set up like this we say as effects as +we've learned in perturbation theories + + align:start position:0% +we've learned in perturbation theories + + + align:start position:0% +we've learned in perturbation theories +as 0 of X plus h bar as 1 of X the first + + align:start position:0% +as 0 of X plus h bar as 1 of X the first + + + align:start position:0% +as 0 of X plus h bar as 1 of X the first +correction plus h bar squared is 2 of X + + align:start position:0% +correction plus h bar squared is 2 of X + + + align:start position:0% +correction plus h bar squared is 2 of X +and higher order now H bar I'm sorry s + + align:start position:0% +and higher order now H bar I'm sorry s + + + align:start position:0% +and higher order now H bar I'm sorry s +already has units of H bar units of H + + align:start position:0% +already has units of H bar units of H + + + align:start position:0% +already has units of H bar units of H +bar so as 0 will have units of H bar to + + align:start position:0% +bar so as 0 will have units of H bar to + + + align:start position:0% +bar so as 0 will have units of H bar to +s 1 for example has no units so each + + align:start position:0% +s 1 for example has no units so each + + + align:start position:0% +s 1 for example has no units so each +term has a different set of units and + + align:start position:0% +term has a different set of units and + + + align:start position:0% +term has a different set of units and +that's okay because H bar has units and + + align:start position:0% +that's okay because H bar has units and + + + align:start position:0% +that's okay because H bar has units and +this will go like 1 over H bar units of + + align:start position:0% +this will go like 1 over H bar units of + + + align:start position:0% +this will go like 1 over H bar units of +1 over H bar and so for and so on so we + + align:start position:0% +1 over H bar and so for and so on so we + + + align:start position:0% +1 over H bar and so for and so on so we +have an expansion and this will call our + + align:start position:0% +have an expansion and this will call our + + + align:start position:0% +have an expansion and this will call our +semi-classical expansion as we applied + + align:start position:0% +semi-classical expansion as we applied + + + align:start position:0% +semi-classical expansion as we applied +now this expansion to that equation we + + align:start position:0% +now this expansion to that equation we + + + align:start position:0% +now this expansion to that equation we +should treat H as we treat at lambda in + + align:start position:0% +should treat H as we treat at lambda in + + + align:start position:0% +should treat H as we treat at lambda in +perturbation theory that is we imagine + + align:start position:0% +perturbation theory that is we imagine + + + align:start position:0% +perturbation theory that is we imagine +that this must be hald order by order in + + align:start position:0% +that this must be hald order by order in + + + align:start position:0% +that this must be hald order by order in +H bar because we imagine we have the + + align:start position:0% +H bar because we imagine we have the + + + align:start position:0% +H bar because we imagine we have the +flexibility of changing H bar + + align:start position:0% +flexibility of changing H bar + + + align:start position:0% +flexibility of changing H bar +so let's do this what do we have an + + align:start position:0% +so let's do this what do we have an + + + align:start position:0% +so let's do this what do we have an +equation we have s prime so the equation + + align:start position:0% +equation we have s prime so the equation + + + align:start position:0% +equation we have s prime so the equation +has s 0 prime plus h bar s 1 prime now I + + align:start position:0% +has s 0 prime plus h bar s 1 prime now I + + + align:start position:0% +has s 0 prime plus h bar s 1 prime now I +will keep terms up to order H bar so I + + align:start position:0% +will keep terms up to order H bar so I + + + align:start position:0% +will keep terms up to order H bar so I +will stop here plus order H bar squared + + align:start position:0% +will stop here plus order H bar squared + + + align:start position:0% +will stop here plus order H bar squared +squared minus IH bar s double prime so + + align:start position:0% +squared minus IH bar s double prime so + + + align:start position:0% +squared minus IH bar s double prime so +that should be s 0 double prime plus + + align:start position:0% +that should be s 0 double prime plus + + + align:start position:0% +that should be s 0 double prime plus +order H bar equal P squared of X so + + align:start position:0% +order H bar equal P squared of X so + + + align:start position:0% +order H bar equal P squared of X so +let's organize our terms we have s 0 + + align:start position:0% +let's organize our terms we have s 0 + + + align:start position:0% +let's organize our terms we have s 0 +prime squared on the left hand side + + align:start position:0% +prime squared on the left hand side + + + align:start position:0% +prime squared on the left hand side +minus P squared of X I bring the P to + + align:start position:0% +minus P squared of X I bring the P to + + + align:start position:0% +minus P squared of X I bring the P to +the left hand side plus h bar so these + + align:start position:0% +the left hand side plus h bar so these + + + align:start position:0% +the left hand side plus h bar so these +are terms that have no H bar and when we + + align:start position:0% +are terms that have no H bar and when we + + + align:start position:0% +are terms that have no H bar and when we +look at H bar from the first term there + + align:start position:0% +look at H bar from the first term there + + + align:start position:0% +look at H bar from the first term there +we expand we square this thing so you + + align:start position:0% +we expand we square this thing so you + + + align:start position:0% +we expand we square this thing so you +can get the cross product between the s + + align:start position:0% +can get the cross product between the s + + + align:start position:0% +can get the cross product between the s +0 Prime and s y prime so you get 2 well + + align:start position:0% +0 Prime and s y prime so you get 2 well + + + align:start position:0% +0 Prime and s y prime so you get 2 well +to the H Prime already there to s 0 + + align:start position:0% +to the H Prime already there to s 0 + + + align:start position:0% +to the H Prime already there to s 0 +prime s 1 Prime and from the second term + + align:start position:0% +prime s 1 Prime and from the second term + + + align:start position:0% +prime s 1 Prime and from the second term +you get minus I + + align:start position:0% + + + + align:start position:0% + +s0 double prime plus order h squared + + align:start position:0% +s0 double prime plus order h squared + + + align:start position:0% +s0 double prime plus order h squared +equals zero so I just collected all the + + align:start position:0% +equals zero so I just collected all the + + + align:start position:0% +equals zero so I just collected all the +terms there so if we're believing in + + align:start position:0% +terms there so if we're believing in + + + align:start position:0% +terms there so if we're believing in +this expansion the first thing we should + + align:start position:0% +this expansion the first thing we should + + + align:start position:0% +this expansion the first thing we should +say that each coefficient in the power + + align:start position:0% +say that each coefficient in the power + + + align:start position:0% +say that each coefficient in the power +series of H bar is zero so we get two + + align:start position:0% +series of H bar is zero so we get two + + + align:start position:0% +series of H bar is zero so we get two +equations first one is s0 prime squared + + align:start position:0% +equations first one is s0 prime squared + + + align:start position:0% +equations first one is s0 prime squared +is equal to P squared of X it's one + + align:start position:0% +is equal to P squared of X it's one + + + align:start position:0% +is equal to P squared of X it's one +that's this term equal to zero and here + + align:start position:0% +that's this term equal to zero and here + + + align:start position:0% +that's this term equal to zero and here +we get let's write it in a way that we + + align:start position:0% +we get let's write it in a way that we + + + align:start position:0% +we get let's write it in a way that we +solve for the unknown supposedly from + + align:start position:0% +solve for the unknown supposedly from + + + align:start position:0% +solve for the unknown supposedly from +this first equation we can solve for x + + align:start position:0% +this first equation we can solve for x + + + align:start position:0% +this first equation we can solve for x +cs0 + + align:start position:0% +cs0 + + + align:start position:0% +cs0 +if you know it's 0 what do you want now + + align:start position:0% +if you know it's 0 what do you want now + + + align:start position:0% +if you know it's 0 what do you want now +to know it says 1 prime so let's write + + align:start position:0% +to know it says 1 prime so let's write + + + align:start position:0% +to know it says 1 prime so let's write +this as s 1 prime is equal to I as 0 + + align:start position:0% +this as s 1 prime is equal to I as 0 + + + align:start position:0% +this as s 1 prime is equal to I as 0 +double prime over to s 0 prime so these + + align:start position:0% +double prime over to s 0 prime so these + + + align:start position:0% +double prime over to s 0 prime so these +are my two equations \ No newline at end of file diff --git a/88tKZLGOr3M.txt b/88tKZLGOr3M.txt new file mode 100644 index 0000000000000000000000000000000000000000..8a4f791f9748922523fdfda6a938ee1092674315 --- /dev/null +++ b/88tKZLGOr3M.txt @@ -0,0 +1,11739 @@ +align:start position:0% + +today we're going to continue building + + align:start position:0% +today we're going to continue building + + + align:start position:0% +today we're going to continue building +our equivalent circuit model of a neuron + + align:start position:0% +our equivalent circuit model of a neuron + + + align:start position:0% +our equivalent circuit model of a neuron +again this is the hodgkin-huxley model + + align:start position:0% +again this is the hodgkin-huxley model + + + align:start position:0% +again this is the hodgkin-huxley model +and it's the model was really developed + + align:start position:0% +and it's the model was really developed + + + align:start position:0% +and it's the model was really developed +around explaining how neurons generate + + align:start position:0% +around explaining how neurons generate + + + align:start position:0% +around explaining how neurons generate +action potentials there are two key ion + + align:start position:0% +action potentials there are two key ion + + + align:start position:0% +action potentials there are two key ion +channels that are associated with making + + align:start position:0% +channels that are associated with making + + + align:start position:0% +channels that are associated with making +spikes there's a sodium a sodium channel + + align:start position:0% +spikes there's a sodium a sodium channel + + + align:start position:0% +spikes there's a sodium a sodium channel +that that we model as a conductance in + + align:start position:0% +that that we model as a conductance in + + + align:start position:0% +that that we model as a conductance in +in series with a battery and there's a + + align:start position:0% +in series with a battery and there's a + + + align:start position:0% +in series with a battery and there's a +potassium conductance that we model the + + align:start position:0% +potassium conductance that we model the + + + align:start position:0% +potassium conductance that we model the +same way and again those two + + align:start position:0% +same way and again those two + + + align:start position:0% +same way and again those two +conductances cooperate to produce an + + align:start position:0% +conductances cooperate to produce an + + + align:start position:0% +conductances cooperate to produce an +action potential and we saw essentially + + align:start position:0% +action potential and we saw essentially + + + align:start position:0% +action potential and we saw essentially +how those two conductances together with + + align:start position:0% +how those two conductances together with + + + align:start position:0% +how those two conductances together with +their batteries the sodium battery is up + + align:start position:0% +their batteries the sodium battery is up + + + align:start position:0% +their batteries the sodium battery is up +at plus 50 or so millivolts the + + align:start position:0% +at plus 50 or so millivolts the + + + align:start position:0% +at plus 50 or so millivolts the +potassium battery is down at minus 75 or + + align:start position:0% +potassium battery is down at minus 75 or + + + align:start position:0% +potassium battery is down at minus 75 or +so millivolts and those two conductances + + align:start position:0% +so millivolts and those two conductances + + + align:start position:0% +so millivolts and those two conductances +then work to connect essentially connect + + align:start position:0% +then work to connect essentially connect + + + align:start position:0% +then work to connect essentially connect +the inside of the neuron to the plus + + align:start position:0% +the inside of the neuron to the plus + + + align:start position:0% +the inside of the neuron to the plus +battery and then to the minus battery to + + align:start position:0% +battery and then to the minus battery to + + + align:start position:0% +battery and then to the minus battery to +give you an action potential and you may + + align:start position:0% +give you an action potential and you may + + + align:start position:0% +give you an action potential and you may +remember that we saw what that looks + + align:start position:0% +remember that we saw what that looks + + + align:start position:0% +remember that we saw what that looks +like so here is plotting membrane + + align:start position:0% +like so here is plotting membrane + + + align:start position:0% +like so here is plotting membrane +potential in blue here we turn on this + + align:start position:0% +potential in blue here we turn on this + + + align:start position:0% +potential in blue here we turn on this +sodium conductance the voltage of the + + align:start position:0% +sodium conductance the voltage of the + + + align:start position:0% +sodium conductance the voltage of the +cell races up to about plus 55 then we + + align:start position:0% +cell races up to about plus 55 then we + + + align:start position:0% +cell races up to about plus 55 then we +turn off the sodium we turn on the + + align:start position:0% +turn off the sodium we turn on the + + + align:start position:0% +turn off the sodium we turn on the +potassium the voltage goes down to minus + + align:start position:0% +potassium the voltage goes down to minus + + + align:start position:0% +potassium the voltage goes down to minus +75 or so and then we turn off both + + align:start position:0% +75 or so and then we turn off both + + + align:start position:0% +75 or so and then we turn off both +conductances and the cell recover so you + + align:start position:0% +conductances and the cell recover so you + + + align:start position:0% +conductances and the cell recover so you +can see that that basically produces + + align:start position:0% +can see that that basically produces + + + align:start position:0% +can see that that basically produces +what looks like an action potential + + align:start position:0% +what looks like an action potential + + + align:start position:0% +what looks like an action potential +that's the basis of produced action + + align:start position:0% +that's the basis of produced action + + + align:start position:0% +that's the basis of produced action +potential production but we need in + + align:start position:0% +potential production but we need in + + + align:start position:0% +potential production but we need in +order to understand how these things + + align:start position:0% +order to understand how these things + + + align:start position:0% +order to understand how these things +turn on and off in the time course that + + align:start position:0% +turn on and off in the time course that + + + align:start position:0% +turn on and off in the time course that +they do we need to understand a little + + align:start position:0% +they do we need to understand a little + + + align:start position:0% +they do we need to understand a little +bit more about how these sodium and + + align:start position:0% +bit more about how these sodium and + + + align:start position:0% +bit more about how these sodium and +potassium conductances work and that's + + align:start position:0% +potassium conductances work and that's + + + align:start position:0% +potassium conductances work and that's +what we're going to focus on today so + + align:start position:0% +what we're going to focus on today so + + + align:start position:0% +what we're going to focus on today so +let's just start building our models so + + align:start position:0% +let's just start building our models so + + + align:start position:0% +let's just start building our models so +each one of those conductances with a + + align:start position:0% +each one of those conductances with a + + + align:start position:0% +each one of those conductances with a +with a battery is associated with a + + align:start position:0% +with a battery is associated with a + + + align:start position:0% +with a battery is associated with a +current there's a current that goes + + align:start position:0% +current there's a current that goes + + + align:start position:0% +current there's a current that goes +through each of those conductances the + + align:start position:0% +through each of those conductances the + + + align:start position:0% +through each of those conductances the +total current through the membrane the + + align:start position:0% +total current through the membrane the + + + align:start position:0% +total current through the membrane the +ionic current through the + + align:start position:0% +ionic current through the + + + align:start position:0% +ionic current through the +membrane in the hodgkin-huxley model is + + align:start position:0% +membrane in the hodgkin-huxley model is + + + align:start position:0% +membrane in the hodgkin-huxley model is +a sum of three components actually a + + align:start position:0% +a sum of three components actually a + + + align:start position:0% +a sum of three components actually a +sodium current a potassium current those + + align:start position:0% +sodium current a potassium current those + + + align:start position:0% +sodium current a potassium current those +two we just talked about and a leak + + align:start position:0% +two we just talked about and a leak + + + align:start position:0% +two we just talked about and a leak +current that is just a fixed current so + + align:start position:0% +current that is just a fixed current so + + + align:start position:0% +current that is just a fixed current so +the sodium and potassium currents are + + align:start position:0% +the sodium and potassium currents are + + + align:start position:0% +the sodium and potassium currents are +functions of time and voltage the leak + + align:start position:0% +functions of time and voltage the leak + + + align:start position:0% +functions of time and voltage the leak +current the leak conductance is just + + align:start position:0% +current the leak conductance is just + + + align:start position:0% +current the leak conductance is just +fixed and it has a battery of about + + align:start position:0% +fixed and it has a battery of about + + + align:start position:0% +fixed and it has a battery of about +minus 50 millivolts and it just tends to + + align:start position:0% +minus 50 millivolts and it just tends to + + + align:start position:0% +minus 50 millivolts and it just tends to +keep the cell sort of hyper polarized + + align:start position:0% +keep the cell sort of hyper polarized + + + align:start position:0% +keep the cell sort of hyper polarized +and these two these two currents these + + align:start position:0% +and these two these two currents these + + + align:start position:0% +and these two these two currents these +two conductances do the job of making an + + align:start position:0% +two conductances do the job of making an + + + align:start position:0% +two conductances do the job of making an +action potential so the total current + + align:start position:0% +action potential so the total current + + + align:start position:0% +action potential so the total current +membrane current is just a sum of those + + align:start position:0% +membrane current is just a sum of those + + + align:start position:0% +membrane current is just a sum of those +three parts and now we can just take + + align:start position:0% +three parts and now we can just take + + + align:start position:0% +three parts and now we can just take +that membrane current and plug it into + + align:start position:0% +that membrane current and plug it into + + + align:start position:0% +that membrane current and plug it into +this equation for the voltage as a + + align:start position:0% +this equation for the voltage as a + + + align:start position:0% +this equation for the voltage as a +function of of current now and solve + + align:start position:0% +function of of current now and solve + + + align:start position:0% +function of of current now and solve +that differential equation to get the + + align:start position:0% +that differential equation to get the + + + align:start position:0% +that differential equation to get the +voltage how to calculate how the voltage + + align:start position:0% +voltage how to calculate how the voltage + + + align:start position:0% +voltage how to calculate how the voltage +evolves in time in the presence of these + + align:start position:0% +evolves in time in the presence of these + + + align:start position:0% +evolves in time in the presence of these +membrane currents okay all right so you + + align:start position:0% +membrane currents okay all right so you + + + align:start position:0% +membrane currents okay all right so you +recall from the last lecture that you + + align:start position:0% +recall from the last lecture that you + + + align:start position:0% +recall from the last lecture that you +watched on video that these currents can + + align:start position:0% +watched on video that these currents can + + + align:start position:0% +watched on video that these currents can +be written down as a conductance so that + + align:start position:0% +be written down as a conductance so that + + + align:start position:0% +be written down as a conductance so that +let's just start here this is the most + + align:start position:0% +let's just start here this is the most + + + align:start position:0% +let's just start here this is the most +similar one to the one that you saw in + + align:start position:0% +similar one to the one that you saw in + + + align:start position:0% +similar one to the one that you saw in +the in the previous lecture the current + + align:start position:0% +the in the previous lecture the current + + + align:start position:0% +the in the previous lecture the current +is just a conductance times a driving + + align:start position:0% +is just a conductance times a driving + + + align:start position:0% +is just a conductance times a driving +potential and we described how that + + align:start position:0% +potential and we described how that + + + align:start position:0% +potential and we described how that +equation can be summarized in electrical + + align:start position:0% +equation can be summarized in electrical + + + align:start position:0% +equation can be summarized in electrical +circuit components as a resistor which + + align:start position:0% +circuit components as a resistor which + + + align:start position:0% +circuit components as a resistor which +is one over the conductance times a + + align:start position:0% +is one over the conductance times a + + + align:start position:0% +is one over the conductance times a +driving potential which is basically + + align:start position:0% +driving potential which is basically + + + align:start position:0% +driving potential which is basically +just the voltage drop across the + + align:start position:0% +just the voltage drop across the + + + align:start position:0% +just the voltage drop across the +conductance okay now each of these + + align:start position:0% +conductance okay now each of these + + + align:start position:0% +conductance okay now each of these +conductance is each of these currents is + + align:start position:0% +conductance is each of these currents is + + + align:start position:0% +conductance is each of these currents is +going to be written down by a very + + align:start position:0% +going to be written down by a very + + + align:start position:0% +going to be written down by a very +similar equation so the potassium + + align:start position:0% +similar equation so the potassium + + + align:start position:0% +similar equation so the potassium +current is just the potassium + + align:start position:0% +current is just the potassium + + + align:start position:0% +current is just the potassium +conductance times the driving potential + + align:start position:0% +conductance times the driving potential + + + align:start position:0% +conductance times the driving potential +for potassium which is just the membrane + + align:start position:0% +for potassium which is just the membrane + + + align:start position:0% +for potassium which is just the membrane +potential minus the ek and the sodium + + align:start position:0% +potential minus the ek and the sodium + + + align:start position:0% +potential minus the ek and the sodium +current is just the sodium conductance + + align:start position:0% +current is just the sodium conductance + + + align:start position:0% +current is just the sodium conductance +times the driving potential for sodium + + align:start position:0% +times the driving potential for sodium + + + align:start position:0% +times the driving potential for sodium +which is the membrane potential minus + + align:start position:0% +which is the membrane potential minus + + + align:start position:0% +which is the membrane potential minus +the sodium batter any questions yes yes + + align:start position:0% +the sodium batter any questions yes yes + + + align:start position:0% +the sodium batter any questions yes yes +so so unless I've made a mistake I've + + align:start position:0% +so so unless I've made a mistake I've + + + align:start position:0% +so so unless I've made a mistake I've +tried to put these remember that the + + align:start position:0% +tried to put these remember that the + + + align:start position:0% +tried to put these remember that the +potassium battery is is minus is + + align:start position:0% +potassium battery is is minus is + + + align:start position:0% +potassium battery is is minus is +negative right and the sodium battery is + + align:start position:0% +negative right and the sodium battery is + + + align:start position:0% +negative right and the sodium battery is +positive so I've tried to show that by + + align:start position:0% +positive so I've tried to show that by + + + align:start position:0% +positive so I've tried to show that by +putting the batteries in the opposite + + align:start position:0% +putting the batteries in the opposite + + + align:start position:0% +putting the batteries in the opposite +direction right so the battery symbol + + align:start position:0% +direction right so the battery symbol + + + align:start position:0% +direction right so the battery symbol +has one side that's that's supposed to + + align:start position:0% +has one side that's that's supposed to + + + align:start position:0% +has one side that's that's supposed to +indicate a positive voltage and the + + align:start position:0% +indicate a positive voltage and the + + + align:start position:0% +indicate a positive voltage and the +other side is negative so because they + + align:start position:0% +other side is negative so because they + + + align:start position:0% +other side is negative so because they +have the opposite sign I put them in + + align:start position:0% +have the opposite sign I put them in + + + align:start position:0% +have the opposite sign I put them in +backwards in the opposite direction does + + align:start position:0% +backwards in the opposite direction does + + + align:start position:0% +backwards in the opposite direction does +that make sense don't worry about that + + align:start position:0% +that make sense don't worry about that + + + align:start position:0% +that make sense don't worry about that +too much if I you know if I ask you to + + align:start position:0% +too much if I you know if I ask you to + + + align:start position:0% +too much if I you know if I ask you to +draw this I don't really care that much + + align:start position:0% +draw this I don't really care that much + + + align:start position:0% +draw this I don't really care that much +which way these things go I just want + + align:start position:0% +which way these things go I just want + + + align:start position:0% +which way these things go I just want +you to know that this one is negative on + + align:start position:0% +you to know that this one is negative on + + + align:start position:0% +you to know that this one is negative on +the inside and the the sodium is + + align:start position:0% +the inside and the the sodium is + + + align:start position:0% +the inside and the the sodium is +positive on the inside this is the + + align:start position:0% +positive on the inside this is the + + + align:start position:0% +positive on the inside this is the +inside of this out here right okay + + align:start position:0% +inside of this out here right okay + + + align:start position:0% +inside of this out here right okay +the sodium battery drives the inside of + + align:start position:0% +the sodium battery drives the inside of + + + align:start position:0% +the sodium battery drives the inside of +the cell toward positive voltage because + + align:start position:0% +the cell toward positive voltage because + + + align:start position:0% +the cell toward positive voltage because +you have positive ions flowing into the + + align:start position:0% +you have positive ions flowing into the + + + align:start position:0% +you have positive ions flowing into the +cell so you can see now that the + + align:start position:0% +cell so you can see now that the + + + align:start position:0% +cell so you can see now that the +membrane potential here depends on the + + align:start position:0% +membrane potential here depends on the + + + align:start position:0% +membrane potential here depends on the +membrane currents right through this + + align:start position:0% +membrane currents right through this + + + align:start position:0% +membrane currents right through this +differential equation but the membrane + + align:start position:0% +differential equation but the membrane + + + align:start position:0% +differential equation but the membrane +currents the sodium potassium and leak + + align:start position:0% +currents the sodium potassium and leak + + + align:start position:0% +currents the sodium potassium and leak +cards all depend on these conductances + + align:start position:0% +cards all depend on these conductances + + + align:start position:0% +cards all depend on these conductances +right and these conductances for the + + align:start position:0% +right and these conductances for the + + + align:start position:0% +right and these conductances for the +sodium and potassium are voltage + + align:start position:0% +sodium and potassium are voltage + + + align:start position:0% +sodium and potassium are voltage +dependent and time dependent so you can + + align:start position:0% +dependent and time dependent so you can + + + align:start position:0% +dependent and time dependent so you can +see that the conductances depend on the + + align:start position:0% +see that the conductances depend on the + + + align:start position:0% +see that the conductances depend on the +voltage right so the membrane potential + + align:start position:0% +voltage right so the membrane potential + + + align:start position:0% +voltage right so the membrane potential +depends on current current depends on + + align:start position:0% +depends on current current depends on + + + align:start position:0% +depends on current current depends on +conductances but the conductance is + + align:start position:0% +conductances but the conductance is + + + align:start position:0% +conductances but the conductance is +depend on the membrane potential so it + + align:start position:0% +depend on the membrane potential so it + + + align:start position:0% +depend on the membrane potential so it +goes around and around and around right + + align:start position:0% +goes around and around and around right + + + align:start position:0% +goes around and around and around right +so those things all depend on each other + + align:start position:0% +so those things all depend on each other + + + align:start position:0% +so those things all depend on each other +and so what we are setting out to do is + + align:start position:0% +and so what we are setting out to do is + + + align:start position:0% +and so what we are setting out to do is +to write down the way those things + + align:start position:0% +to write down the way those things + + + align:start position:0% +to write down the way those things +depend on each other the way you can + + align:start position:0% +depend on each other the way you can + + + align:start position:0% +depend on each other the way you can +think about that system evolving in time + + align:start position:0% +think about that system evolving in time + + + align:start position:0% +think about that system evolving in time +so let me just show you what the planet + + align:start position:0% +so let me just show you what the planet + + + align:start position:0% +so let me just show you what the planet +so the plan is to write down an + + align:start position:0% +so the plan is to write down an + + + align:start position:0% +so the plan is to write down an +algorithm basically a for loop + + align:start position:0% +algorithm basically a for loop + + + align:start position:0% +algorithm basically a for loop +that describes how the membrane how the + + align:start position:0% +that describes how the membrane how the + + + align:start position:0% +that describes how the membrane how the +neuron generates an action potential let + + align:start position:0% +neuron generates an action potential let + + + align:start position:0% +neuron generates an action potential let +me just walk you through the steps of + + align:start position:0% +me just walk you through the steps of + + + align:start position:0% +me just walk you through the steps of +that and then I'll get to your question + + align:start position:0% +that and then I'll get to your question + + + align:start position:0% +that and then I'll get to your question +so we're going to start with some + + align:start position:0% +so we're going to start with some + + + align:start position:0% +so we're going to start with some +membrane potential V and we're going to + + align:start position:0% +membrane potential V and we're going to + + + align:start position:0% +membrane potential V and we're going to +calculate the the voltage dependent + + align:start position:0% +calculate the the voltage dependent + + + align:start position:0% +calculate the the voltage dependent +parameters of the sodium and potassium + + align:start position:0% +parameters of the sodium and potassium + + + align:start position:0% +parameters of the sodium and potassium +conductance using that membrane + + align:start position:0% +conductance using that membrane + + + align:start position:0% +conductance using that membrane +potential and once we have those + + align:start position:0% +potential and once we have those + + + align:start position:0% +potential and once we have those +parameters we can actually calculate the + + align:start position:0% +parameters we can actually calculate the + + + align:start position:0% +parameters we can actually calculate the +conductance for each of those for the + + align:start position:0% +conductance for each of those for the + + + align:start position:0% +conductance for each of those for the +sodium and potassium once you know the + + align:start position:0% +sodium and potassium once you know the + + + align:start position:0% +sodium and potassium once you know the +conductance you can get the currents + + align:start position:0% +conductance you can get the currents + + + align:start position:0% +conductance you can get the currents +once you have the currents you can + + align:start position:0% +once you have the currents you can + + + align:start position:0% +once you have the currents you can +compute the total membrane current just + + align:start position:0% +compute the total membrane current just + + + align:start position:0% +compute the total membrane current just +by adding them all together then you can + + align:start position:0% +by adding them all together then you can + + + align:start position:0% +by adding them all together then you can +compute once you have all those currents + + align:start position:0% +compute once you have all those currents + + + align:start position:0% +compute once you have all those currents +you just compute V infinity which is + + align:start position:0% +you just compute V infinity which is + + + align:start position:0% +you just compute V infinity which is +just the current times the resistance + + align:start position:0% +just the current times the resistance + + + align:start position:0% +just the current times the resistance +the effective resistance then we're + + align:start position:0% +the effective resistance then we're + + + align:start position:0% +the effective resistance then we're +going to integrate our first-order + + align:start position:0% +going to integrate our first-order + + + align:start position:0% +going to integrate our first-order +linear differential equation to get a + + align:start position:0% +linear differential equation to get a + + + align:start position:0% +linear differential equation to get a +new voltage as a function of being a + + align:start position:0% +new voltage as a function of being a + + + align:start position:0% +new voltage as a function of being a +time and B infinity and then we're just + + align:start position:0% +time and B infinity and then we're just + + + align:start position:0% +time and B infinity and then we're just +going to go back and start again so + + align:start position:0% +going to go back and start again so + + + align:start position:0% +going to go back and start again so +that's the algorithm that a neuron uses + + align:start position:0% +that's the algorithm that a neuron uses + + + align:start position:0% +that's the algorithm that a neuron uses +to generate a spike okay and that's what + + align:start position:0% +to generate a spike okay and that's what + + + align:start position:0% +to generate a spike okay and that's what +we're going to work out now we've talked + + align:start position:0% +we're going to work out now we've talked + + + align:start position:0% +we're going to work out now we've talked +about these things over the last few + + align:start position:0% +about these things over the last few + + + align:start position:0% +about these things over the last few +lectures how you can how you can relate + + align:start position:0% +lectures how you can how you can relate + + + align:start position:0% +lectures how you can how you can relate +total current to V infinity and then + + align:start position:0% +total current to V infinity and then + + + align:start position:0% +total current to V infinity and then +integrate a first-order linear + + align:start position:0% +integrate a first-order linear + + + align:start position:0% +integrate a first-order linear +differential equation which is just + + align:start position:0% +differential equation which is just + + + align:start position:0% +differential equation which is just +relaxing exponentially toward the + + align:start position:0% +relaxing exponentially toward the + + + align:start position:0% +relaxing exponentially toward the +infinity but now we're going to put + + align:start position:0% +infinity but now we're going to put + + + align:start position:0% +infinity but now we're going to put +these things in figure out the voltage + + align:start position:0% +these things in figure out the voltage + + + align:start position:0% +these things in figure out the voltage +and time dependence of the sodium and + + align:start position:0% +and time dependence of the sodium and + + + align:start position:0% +and time dependence of the sodium and +potassium conductances yes yes it's + + align:start position:0% +potassium conductances yes yes it's + + + align:start position:0% +potassium conductances yes yes it's +primarily potassium it has a negative + + align:start position:0% +primarily potassium it has a negative + + + align:start position:0% +primarily potassium it has a negative +potential but it's just constant so + + align:start position:0% +potential but it's just constant so + + + align:start position:0% +potential but it's just constant so +we're not really going to pay much + + align:start position:0% +we're not really going to pay much + + + align:start position:0% +we're not really going to pay much +attention to it okay so if the sodium + + align:start position:0% +attention to it okay so if the sodium + + + align:start position:0% +attention to it okay so if the sodium +and potassium currents are off then the + + align:start position:0% +and potassium currents are off then the + + + align:start position:0% +and potassium currents are off then the +leak current still keeps the cell + + align:start position:0% +leak current still keeps the cell + + + align:start position:0% +leak current still keeps the cell +hyperpolarized okay + + align:start position:0% +hyperpolarized okay + + + align:start position:0% +hyperpolarized okay +all right any questions that's the big + + align:start position:0% +all right any questions that's the big + + + align:start position:0% +all right any questions that's the big +picture + + align:start position:0% +picture + + + align:start position:0% +picture +okay so here are our learning objectives + + align:start position:0% +okay so here are our learning objectives + + + align:start position:0% +okay so here are our learning objectives +I'd like you to be able to draw that + + align:start position:0% +I'd like you to be able to draw that + + + align:start position:0% +I'd like you to be able to draw that +circuit diagram not worrying about the + + align:start position:0% +circuit diagram not worrying about the + + + align:start position:0% +circuit diagram not worrying about the +long and short sides of the battery I'm + + align:start position:0% +long and short sides of the battery I'm + + + align:start position:0% +long and short sides of the battery I'm +going to we're going to talk about how + + align:start position:0% +going to we're going to talk about how + + + align:start position:0% +going to we're going to talk about how +we measure the properties of ion + + align:start position:0% +we measure the properties of ion + + + align:start position:0% +we measure the properties of ion +channels + + align:start position:0% +channels + + + align:start position:0% +channels +that's called a voltage clamp so I want + + align:start position:0% +that's called a voltage clamp so I want + + + align:start position:0% +that's called a voltage clamp so I want +you to be able to describe what that is + + align:start position:0% +you to be able to describe what that is + + + align:start position:0% +you to be able to describe what that is +I'd like you to be able to plot the + + align:start position:0% +I'd like you to be able to plot the + + + align:start position:0% +I'd like you to be able to plot the +voltage and time dependence of of the + + align:start position:0% +voltage and time dependence of of the + + + align:start position:0% +voltage and time dependence of of the +potassium current for today the next + + align:start position:0% +potassium current for today the next + + + align:start position:0% +potassium current for today the next +lecture we'll talk about the sodium + + align:start position:0% +lecture we'll talk about the sodium + + + align:start position:0% +lecture we'll talk about the sodium +current so we'll add that to our list of + + align:start position:0% +current so we'll add that to our list of + + + align:start position:0% +current so we'll add that to our list of +things that we need to know but for + + align:start position:0% +things that we need to know but for + + + align:start position:0% +things that we need to know but for +today I'd like you to be able to plot + + align:start position:0% +today I'd like you to be able to plot + + + align:start position:0% +today I'd like you to be able to plot +the voltage and time dependence of the + + align:start position:0% +the voltage and time dependence of the + + + align:start position:0% +the voltage and time dependence of the +potassium current and conductance and be + + align:start position:0% +potassium current and conductance and be + + + align:start position:0% +potassium current and conductance and be +able to explain biophysically where the + + align:start position:0% +able to explain biophysically where the + + + align:start position:0% +able to explain biophysically where the +time and voltage dependence of that + + align:start position:0% +time and voltage dependence of that + + + align:start position:0% +time and voltage dependence of that +potassium conductance comes from and be + + align:start position:0% +potassium conductance comes from and be + + + align:start position:0% +potassium conductance comes from and be +able to write it down in terms of + + align:start position:0% +able to write it down in terms of + + + align:start position:0% +able to write it down in terms of +quantities that we're going to call that + + align:start position:0% +quantities that we're going to call that + + + align:start position:0% +quantities that we're going to call that +are called the hodgkin-huxley gating + + align:start position:0% +are called the hodgkin-huxley gating + + + align:start position:0% +are called the hodgkin-huxley gating +variables okay so that's that's the plan + + align:start position:0% +variables okay so that's that's the plan + + + align:start position:0% +variables okay so that's that's the plan +all right so let's come back to our + + align:start position:0% +all right so let's come back to our + + + align:start position:0% +all right so let's come back to our +circuit again we have a sodium current + + align:start position:0% +circuit again we have a sodium current + + + align:start position:0% +circuit again we have a sodium current +that's the sodium conductance times the + + align:start position:0% +that's the sodium conductance times the + + + align:start position:0% +that's the sodium conductance times the +sodium driving potential the conductance + + align:start position:0% +sodium driving potential the conductance + + + align:start position:0% +sodium driving potential the conductance +is voltage and time dependent the + + align:start position:0% +is voltage and time dependent the + + + align:start position:0% +is voltage and time dependent the +equilibrium potential for sodium again + + align:start position:0% +equilibrium potential for sodium again + + + align:start position:0% +equilibrium potential for sodium again +is plus 55 millivolts the potassium + + align:start position:0% +is plus 55 millivolts the potassium + + + align:start position:0% +is plus 55 millivolts the potassium +current is just potassium conductance + + align:start position:0% +current is just potassium conductance + + + align:start position:0% +current is just potassium conductance +times the potassium driving potential + + align:start position:0% +times the potassium driving potential + + + align:start position:0% +times the potassium driving potential +that the driving potential is reference + + align:start position:0% +that the driving potential is reference + + + align:start position:0% +that the driving potential is reference +to a battery and equilibrium potential + + align:start position:0% +to a battery and equilibrium potential + + + align:start position:0% +to a battery and equilibrium potential +at minus 75 and the leak has a battery + + align:start position:0% +at minus 75 and the leak has a battery + + + align:start position:0% +at minus 75 and the leak has a battery +at minus 50 millivolts okay so those are + + align:start position:0% +at minus 50 millivolts okay so those are + + + align:start position:0% +at minus 50 millivolts okay so those are +the parts we're going to use we're going + + align:start position:0% +the parts we're going to use we're going + + + align:start position:0% +the parts we're going to use we're going +to describe now the experiments that + + align:start position:0% +to describe now the experiments that + + + align:start position:0% +to describe now the experiments that +hodgkin and huxley did to extract the + + align:start position:0% +hodgkin and huxley did to extract the + + + align:start position:0% +hodgkin and huxley did to extract the +parameters of the sodium and potassium + + align:start position:0% +parameters of the sodium and potassium + + + align:start position:0% +parameters of the sodium and potassium +conductances today we're going to focus + + align:start position:0% +conductances today we're going to focus + + + align:start position:0% +conductances today we're going to focus +on the potassium conductances and then + + align:start position:0% +on the potassium conductances and then + + + align:start position:0% +on the potassium conductances and then +on next Tuesday I guess we're going to + + align:start position:0% +on next Tuesday I guess we're going to + + + align:start position:0% +on next Tuesday I guess we're going to +do the sodium all right so the reason + + align:start position:0% +do the sodium all right so the reason + + + align:start position:0% +do the sodium all right so the reason +hodgkin and huxley studied so so they + + align:start position:0% +hodgkin and huxley studied so so they + + + align:start position:0% +hodgkin and huxley studied so so they +studied these but these channels that + + align:start position:0% +studied these but these channels that + + + align:start position:0% +studied these but these channels that +potassium and sodium channels in the + + align:start position:0% +potassium and sodium channels in the + + + align:start position:0% +potassium and sodium channels in the +giant squid axon now this is most of our + + align:start position:0% +giant squid axon now this is most of our + + + align:start position:0% +giant squid axon now this is most of our +axons are about a microp most of the + + align:start position:0% +axons are about a microp most of the + + + align:start position:0% +axons are about a microp most of the +axons in our brain are about a micron + + align:start position:0% +axons in our brain are about a micron + + + align:start position:0% +axons in our brain are about a micron +across + + align:start position:0% +across + + + align:start position:0% +across +this axon is about a millimeter across + + align:start position:0% +this axon is about a millimeter across + + + align:start position:0% +this axon is about a millimeter across +action potentials propagate much faster + + align:start position:0% +action potentials propagate much faster + + + align:start position:0% +action potentials propagate much faster +in large axons and this axon is involved + + align:start position:0% +in large axons and this axon is involved + + + align:start position:0% +in large axons and this axon is involved +in transmitting an action potential from + + align:start position:0% +in transmitting an action potential from + + + align:start position:0% +in transmitting an action potential from +the brain to the tail that drives an + + align:start position:0% +the brain to the tail that drives an + + + align:start position:0% +the brain to the tail that drives an +escape reflex that the squid squirts + + align:start position:0% +escape reflex that the squid squirts + + + align:start position:0% +escape reflex that the squid squirts +water out of a sort of a chamber that + + align:start position:0% +water out of a sort of a chamber that + + + align:start position:0% +water out of a sort of a chamber that +has water in it if the squid senses + + align:start position:0% +has water in it if the squid senses + + + align:start position:0% +has water in it if the squid senses +danger it contracts muscles that squeeze + + align:start position:0% +danger it contracts muscles that squeeze + + + align:start position:0% +danger it contracts muscles that squeeze +water out of that and it makes a jet and + + align:start position:0% +water out of that and it makes a jet and + + + align:start position:0% +water out of that and it makes a jet and +it squirts the squid forward away from + + align:start position:0% +it squirts the squid forward away from + + + align:start position:0% +it squirts the squid forward away from +danger okay so that action potential has + + align:start position:0% +danger okay so that action potential has + + + align:start position:0% +danger okay so that action potential has +to propagate very quickly from the brain + + align:start position:0% +to propagate very quickly from the brain + + + align:start position:0% +to propagate very quickly from the brain +to the tail and it does that through + + align:start position:0% +to the tail and it does that through + + + align:start position:0% +to the tail and it does that through +this enormous axon that axon is so big + + align:start position:0% +this enormous axon that axon is so big + + + align:start position:0% +this enormous axon that axon is so big +you can now put multiple wires inside of + + align:start position:0% +you can now put multiple wires inside of + + + align:start position:0% +you can now put multiple wires inside of +it you don't even need to pull these + + align:start position:0% +it you don't even need to pull these + + + align:start position:0% +it you don't even need to pull these +glass electrodes you can just take + + align:start position:0% +glass electrodes you can just take + + + align:start position:0% +glass electrodes you can just take +little wires and stick them and chop out + + align:start position:0% +little wires and stick them and chop out + + + align:start position:0% +little wires and stick them and chop out +a little piece of the axon and stick + + align:start position:0% +a little piece of the axon and stick + + + align:start position:0% +a little piece of the axon and stick +wires inside of it and study it yes yes + + align:start position:0% + + + + align:start position:0% + +that's that you eat that part and you + + align:start position:0% +that's that you eat that part and you + + + align:start position:0% +that's that you eat that part and you +eat that part not that that you throw + + align:start position:0% +eat that part not that that you throw + + + align:start position:0% +eat that part not that that you throw +away the most interesting part okay any + + align:start position:0% +away the most interesting part okay any + + + align:start position:0% +away the most interesting part okay any +other questions okay all right so now + + align:start position:0% +other questions okay all right so now + + + align:start position:0% +other questions okay all right so now +we're setting out to measure these + + align:start position:0% +we're setting out to measure these + + + align:start position:0% +we're setting out to measure these +sodium and potassium conductances okay + + align:start position:0% +sodium and potassium conductances okay + + + align:start position:0% +sodium and potassium conductances okay +so how do we do that so what we really + + align:start position:0% +so how do we do that so what we really + + + align:start position:0% +so how do we do that so what we really +want to do is to set we want to measure + + align:start position:0% +want to do is to set we want to measure + + + align:start position:0% +want to do is to set we want to measure +conductance which is the relation + + align:start position:0% +conductance which is the relation + + + align:start position:0% +conductance which is the relation +between voltage and current so we'd like + + align:start position:0% +between voltage and current so we'd like + + + align:start position:0% +between voltage and current so we'd like +to do is to be able to set the voltage + + align:start position:0% +to do is to be able to set the voltage + + + align:start position:0% +to do is to be able to set the voltage +at a certain level and measure the + + align:start position:0% +at a certain level and measure the + + + align:start position:0% +at a certain level and measure the +current that flows through these + + align:start position:0% +current that flows through these + + + align:start position:0% +current that flows through these +channels okay so you really want to plot + + align:start position:0% +channels okay so you really want to plot + + + align:start position:0% +channels okay so you really want to plot +the IV curve right you want to set the + + align:start position:0% +the IV curve right you want to set the + + + align:start position:0% +the IV curve right you want to set the +voltage measure the current and do that + + align:start position:0% +voltage measure the current and do that + + + align:start position:0% +voltage measure the current and do that +at a bunch of different voltages and you + + align:start position:0% +at a bunch of different voltages and you + + + align:start position:0% +at a bunch of different voltages and you +recall that the conductance is basically + + align:start position:0% +recall that the conductance is basically + + + align:start position:0% +recall that the conductance is basically +just the slope of that curve right that + + align:start position:0% +just the slope of that curve right that + + + align:start position:0% +just the slope of that curve right that +line okay so the job is set voltage + + align:start position:0% +line okay so the job is set voltage + + + align:start position:0% +line okay so the job is set voltage +measure current extract conductance now + + align:start position:0% +measure current extract conductance now + + + align:start position:0% +measure current extract conductance now +the problem with that is that as soon as + + align:start position:0% +the problem with that is that as soon as + + + align:start position:0% +the problem with that is that as soon as +you set the voltage of the cell of the + + align:start position:0% +you set the voltage of the cell of the + + + align:start position:0% +you set the voltage of the cell of the +axon somewhere up here in an interest + + align:start position:0% +axon somewhere up here in an interest + + + align:start position:0% +axon somewhere up here in an interest +in range the thing begins to spike and + + align:start position:0% +in range the thing begins to spike and + + + align:start position:0% +in range the thing begins to spike and +then the voltage is no longer constant + + align:start position:0% +then the voltage is no longer constant + + + align:start position:0% +then the voltage is no longer constant +right so it becomes really hard to make + + align:start position:0% +right so it becomes really hard to make + + + align:start position:0% +right so it becomes really hard to make +measurements like this if you depolarize + + align:start position:0% +measurements like this if you depolarize + + + align:start position:0% +measurements like this if you depolarize +the cell a little bit to set try to set + + align:start position:0% +the cell a little bit to set try to set + + + align:start position:0% +the cell a little bit to set try to set +the voltage and all of a sudden it's + + align:start position:0% +the voltage and all of a sudden it's + + + align:start position:0% +the voltage and all of a sudden it's +like generating spikes okay so what do + + align:start position:0% +like generating spikes okay so what do + + + align:start position:0% +like generating spikes okay so what do +you do so the trick is to develop a + + align:start position:0% +you do so the trick is to develop a + + + align:start position:0% +you do so the trick is to develop a +device called the voltage clamp this + + align:start position:0% +device called the voltage clamp this + + + align:start position:0% +device called the voltage clamp this +thing basically holds the member so look + + align:start position:0% +thing basically holds the member so look + + + align:start position:0% +thing basically holds the member so look +if you were if the action potential were + + align:start position:0% +if you were if the action potential were + + + align:start position:0% +if you were if the action potential were +really really slow then you could + + align:start position:0% +really really slow then you could + + + align:start position:0% +really really slow then you could +actually set the voltage but you could + + align:start position:0% +actually set the voltage but you could + + + align:start position:0% +actually set the voltage but you could +inject change the current being injected + + align:start position:0% +inject change the current being injected + + + align:start position:0% +inject change the current being injected +into the cell by hand you say okay I'm + + align:start position:0% +into the cell by hand you say okay I'm + + + align:start position:0% +into the cell by hand you say okay I'm +trying to set the voltage at zero oh it + + align:start position:0% +trying to set the voltage at zero oh it + + + align:start position:0% +trying to set the voltage at zero oh it +got a little bit too high so I turn the + + align:start position:0% +got a little bit too high so I turn the + + + align:start position:0% +got a little bit too high so I turn the +current down now the voltage has gone + + align:start position:0% +current down now the voltage has gone + + + align:start position:0% +current down now the voltage has gone +too low so now I turn the current up + + align:start position:0% +too low so now I turn the current up + + + align:start position:0% +too low so now I turn the current up +like you could do it by hand if the + + align:start position:0% +like you could do it by hand if the + + + align:start position:0% +like you could do it by hand if the +action potential were super slow if it + + align:start position:0% +action potential were super slow if it + + + align:start position:0% +action potential were super slow if it +took a minute to generate right but the + + align:start position:0% +took a minute to generate right but the + + + align:start position:0% +took a minute to generate right but the +action potential takes a millisecond so + + align:start position:0% +action potential takes a millisecond so + + + align:start position:0% +action potential takes a millisecond so +that's just too fast for you to follow + + align:start position:0% +that's just too fast for you to follow + + + align:start position:0% +that's just too fast for you to follow +so you just make a little electrical + + align:start position:0% +so you just make a little electrical + + + align:start position:0% +so you just make a little electrical +circuit that does that job for you okay + + align:start position:0% +circuit that does that job for you okay + + + align:start position:0% +circuit that does that job for you okay +it uses feedback to set the voltage + + align:start position:0% +it uses feedback to set the voltage + + + align:start position:0% +it uses feedback to set the voltage +where you want so you put up you here's + + align:start position:0% +where you want so you put up you here's + + + align:start position:0% +where you want so you put up you here's +yourself + + align:start position:0% +yourself + + + align:start position:0% +yourself +here's your membrane put your membrane + + align:start position:0% +here's your membrane put your membrane + + + align:start position:0% +here's your membrane put your membrane +resistance or conductance that you're + + align:start position:0% +resistance or conductance that you're + + + align:start position:0% +resistance or conductance that you're +trying to measure + + align:start position:0% +trying to measure + + + align:start position:0% +trying to measure +you put a electrode in the cell you put + + align:start position:0% +you put a electrode in the cell you put + + + align:start position:0% +you put a electrode in the cell you put +it into a little amplifier called an + + align:start position:0% +it into a little amplifier called an + + + align:start position:0% +it into a little amplifier called an +operational amplifier so and then on the + + align:start position:0% +operational amplifier so and then on the + + + align:start position:0% +operational amplifier so and then on the +other side of that amplifier the + + align:start position:0% +other side of that amplifier the + + + align:start position:0% +other side of that amplifier the +differential amplifier you you put the + + align:start position:0% +differential amplifier you you put the + + + align:start position:0% +differential amplifier you you put the +command voltage that you're trying to + + align:start position:0% +command voltage that you're trying to + + + align:start position:0% +command voltage that you're trying to +set so here's the way it works basically + + align:start position:0% +set so here's the way it works basically + + + align:start position:0% +set so here's the way it works basically +this thing tries to set the membrane + + align:start position:0% +this thing tries to set the membrane + + + align:start position:0% +this thing tries to set the membrane +potential it tries to make this value + + align:start position:0% +potential it tries to make this value + + + align:start position:0% +potential it tries to make this value +this voltage equal to that voltage and + + align:start position:0% +this voltage equal to that voltage and + + + align:start position:0% +this voltage equal to that voltage and +it does that by feeding current back + + align:start position:0% +it does that by feeding current back + + + align:start position:0% +it does that by feeding current back +into this zone does that make sense okay + + align:start position:0% +into this zone does that make sense okay + + + align:start position:0% +into this zone does that make sense okay +so you use an operational amplifier an + + align:start position:0% +so you use an operational amplifier an + + + align:start position:0% +so you use an operational amplifier an +op amp has two inputs a plus input a + + align:start position:0% +op amp has two inputs a plus input a + + + align:start position:0% +op amp has two inputs a plus input a +minus input the output is just a gain + + align:start position:0% +minus input the output is just a gain + + + align:start position:0% +minus input the output is just a gain +times that plus input minus the positive + + align:start position:0% +times that plus input minus the positive + + + align:start position:0% +times that plus input minus the positive +input minus the negative input and the + + align:start position:0% +input minus the negative input and the + + + align:start position:0% +input minus the negative input and the +gain is really big it's about a million + + align:start position:0% +gain is really big it's about a million + + + align:start position:0% +gain is really big it's about a million +so if this input is a little bit above + + align:start position:0% +so if this input is a little bit above + + + align:start position:0% +so if this input is a little bit above +that import this output is big and + + align:start position:0% +that import this output is big and + + + align:start position:0% +that import this output is big and +positive if this input is less than that + + align:start position:0% +positive if this input is less than that + + + align:start position:0% +positive if this input is less than that +input you can see this is negative and + + align:start position:0% +input you can see this is negative and + + + align:start position:0% +input you can see this is negative and +so + + align:start position:0% +so + + + align:start position:0% +so +output is big and negative any questions + + align:start position:0% +output is big and negative any questions + + + align:start position:0% +output is big and negative any questions +okay so don't get confused here that G + + align:start position:0% +okay so don't get confused here that G + + + align:start position:0% +okay so don't get confused here that G +is gain not not conductance okay just + + align:start position:0% +is gain not not conductance okay just + + + align:start position:0% +is gain not not conductance okay just +just for the next few slides okay so how + + align:start position:0% +just for the next few slides okay so how + + + align:start position:0% +just for the next few slides okay so how +does this work you can see that if the + + align:start position:0% +does this work you can see that if the + + + align:start position:0% +does this work you can see that if the +membrane potential is less than the + + align:start position:0% +membrane potential is less than the + + + align:start position:0% +membrane potential is less than the +command voltage then the output voltage + + align:start position:0% +command voltage then the output voltage + + + align:start position:0% +command voltage then the output voltage +is is positive and big that drives + + align:start position:0% +is is positive and big that drives + + + align:start position:0% +is is positive and big that drives +current into the cell which increases + + align:start position:0% +current into the cell which increases + + + align:start position:0% +current into the cell which increases +the membrane potential and makes it + + align:start position:0% +the membrane potential and makes it + + + align:start position:0% +the membrane potential and makes it +approach the command voltage if the + + align:start position:0% +approach the command voltage if the + + + align:start position:0% +approach the command voltage if the +membrane potential is larger than the + + align:start position:0% +membrane potential is larger than the + + + align:start position:0% +membrane potential is larger than the +command voltage then this thing this is + + align:start position:0% +command voltage then this thing this is + + + align:start position:0% +command voltage then this thing this is +bigger than this so this is negative and + + align:start position:0% +bigger than this so this is negative and + + + align:start position:0% +bigger than this so this is negative and +that pulse current out of the neuron and + + align:start position:0% +that pulse current out of the neuron and + + + align:start position:0% +that pulse current out of the neuron and +decreases the membrane potential and in + + align:start position:0% +decreases the membrane potential and in + + + align:start position:0% +decreases the membrane potential and in +both cases the membrane potential is + + align:start position:0% +both cases the membrane potential is + + + align:start position:0% +both cases the membrane potential is +being pulled toward the command voltage + + align:start position:0% +being pulled toward the command voltage + + + align:start position:0% +being pulled toward the command voltage +and you can show if you just plug in + + align:start position:0% +and you can show if you just plug in + + + align:start position:0% +and you can show if you just plug in +these variables into into a couple of + + align:start position:0% +these variables into into a couple of + + + align:start position:0% +these variables into into a couple of +equations that as long as the gain is + + align:start position:0% +equations that as long as the gain is + + + align:start position:0% +equations that as long as the gain is +big enough the membrane potential is + + align:start position:0% +big enough the membrane potential is + + + align:start position:0% +big enough the membrane potential is +forced to be very close to the command + + align:start position:0% +forced to be very close to the command + + + align:start position:0% +forced to be very close to the command +voltage all right so that's the voltage + + align:start position:0% +voltage all right so that's the voltage + + + align:start position:0% +voltage all right so that's the voltage +clamp it drives whatever current is + + align:start position:0% +clamp it drives whatever current is + + + align:start position:0% +clamp it drives whatever current is +necessary to clamp the voltage of the + + align:start position:0% +necessary to clamp the voltage of the + + + align:start position:0% +necessary to clamp the voltage of the +cell at the command voltage and then + + align:start position:0% +cell at the command voltage and then + + + align:start position:0% +cell at the command voltage and then +what we do is during an experiment we + + align:start position:0% +what we do is during an experiment we + + + align:start position:0% +what we do is during an experiment we +step the command voltage around the cell + + align:start position:0% +step the command voltage around the cell + + + align:start position:0% +step the command voltage around the cell +tries to spike those currents turn on + + align:start position:0% +tries to spike those currents turn on + + + align:start position:0% +tries to spike those currents turn on +the cell tries to spike but this thing + + align:start position:0% +the cell tries to spike but this thing + + + align:start position:0% +the cell tries to spike but this thing +keeps the voltage locked at whatever it + + align:start position:0% +keeps the voltage locked at whatever it + + + align:start position:0% +keeps the voltage locked at whatever it +is that you want we want the voltage to + + align:start position:0% +is that you want we want the voltage to + + + align:start position:0% +is that you want we want the voltage to +be okay and then you measure the amount + + align:start position:0% +be okay and then you measure the amount + + + align:start position:0% +be okay and then you measure the amount +of current required you just measure the + + align:start position:0% +of current required you just measure the + + + align:start position:0% +of current required you just measure the +amount of current flowing through this + + align:start position:0% +amount of current flowing through this + + + align:start position:0% +amount of current flowing through this +resistor here that's required to hold + + align:start position:0% +resistor here that's required to hold + + + align:start position:0% +resistor here that's required to hold +the the cell at any voltage all right + + align:start position:0% +the the cell at any voltage all right + + + align:start position:0% +the the cell at any voltage all right +any questions voltage clamp very cool + + align:start position:0% + + + + align:start position:0% + +yes + + align:start position:0% +yes + + + align:start position:0% +yes +gain is just the multiplier here in this + + align:start position:0% +gain is just the multiplier here in this + + + align:start position:0% +gain is just the multiplier here in this +equation so if there's a tiny difference + + align:start position:0% +equation so if there's a tiny difference + + + align:start position:0% +equation so if there's a tiny difference +between the two inputs the output is big + + align:start position:0% +between the two inputs the output is big + + + align:start position:0% +between the two inputs the output is big +that's that's what gain means right + + align:start position:0% + + + + align:start position:0% + +so if there's a mite if the gain is a + + align:start position:0% +so if there's a mite if the gain is a + + + align:start position:0% +so if there's a mite if the gain is a +million if there's a microvolt + + align:start position:0% +million if there's a microvolt + + + align:start position:0% +million if there's a microvolt +difference between the two inputs the + + align:start position:0% +difference between the two inputs the + + + align:start position:0% +difference between the two inputs the +output will be about a volt and it'll be + + align:start position:0% +output will be about a volt and it'll be + + + align:start position:0% +output will be about a volt and it'll be +plus or minus depending on which of + + align:start position:0% +plus or minus depending on which of + + + align:start position:0% +plus or minus depending on which of +those two was was more positive okay + + align:start position:0% +those two was was more positive okay + + + align:start position:0% +those two was was more positive okay +okay so now let's get to the actual + + align:start position:0% +okay so now let's get to the actual + + + align:start position:0% +okay so now let's get to the actual +voltage clamp experiment that hodgkin + + align:start position:0% +voltage clamp experiment that hodgkin + + + align:start position:0% +voltage clamp experiment that hodgkin +and huxley did we have here we had two + + align:start position:0% +and huxley did we have here we had two + + + align:start position:0% +and huxley did we have here we had two +wires in our cell one to measure voltage + + align:start position:0% +wires in our cell one to measure voltage + + + align:start position:0% +wires in our cell one to measure voltage +and the other one to inject current + + align:start position:0% +and the other one to inject current + + + align:start position:0% +and the other one to inject current +that's exactly what they did there's one + + align:start position:0% +that's exactly what they did there's one + + + align:start position:0% +that's exactly what they did there's one +wire here that's a little piece of axon + + align:start position:0% +wire here that's a little piece of axon + + + align:start position:0% +wire here that's a little piece of axon +you can literally take the cut the squid + + align:start position:0% +you can literally take the cut the squid + + + align:start position:0% +you can literally take the cut the squid +open find that axon it's a big white + + align:start position:0% +open find that axon it's a big white + + + align:start position:0% +open find that axon it's a big white +looking tube about a millimeter across + + align:start position:0% +looking tube about a millimeter across + + + align:start position:0% +looking tube about a millimeter across +cut two pieces of it take two wires + + align:start position:0% +cut two pieces of it take two wires + + + align:start position:0% +cut two pieces of it take two wires +stick one in each end and I drew that + + align:start position:0% +stick one in each end and I drew that + + + align:start position:0% +stick one in each end and I drew that +like this but if you did it that way + + align:start position:0% +like this but if you did it that way + + + align:start position:0% +like this but if you did it that way +they'd probably short together so then + + align:start position:0% +they'd probably short together so then + + + align:start position:0% +they'd probably short together so then +one of those measures the voltage you + + align:start position:0% +one of those measures the voltage you + + + align:start position:0% +one of those measures the voltage you +set a command and the other wire allows + + align:start position:0% +set a command and the other wire allows + + + align:start position:0% +set a command and the other wire allows +you to inject current inside the axon it + + align:start position:0% +you to inject current inside the axon it + + + align:start position:0% +you to inject current inside the axon it +and then you seal the ends with a little + + align:start position:0% +and then you seal the ends with a little + + + align:start position:0% +and then you seal the ends with a little +bit of Vaseline okay yes we see is the + + align:start position:0% +bit of Vaseline okay yes we see is the + + + align:start position:0% +bit of Vaseline okay yes we see is the +command voltage that you're trying to + + align:start position:0% +command voltage that you're trying to + + + align:start position:0% +command voltage that you're trying to +set the inside of the cell to okay + + align:start position:0% +set the inside of the cell to okay + + + align:start position:0% +set the inside of the cell to okay +remember here we're setting the the V + + align:start position:0% +remember here we're setting the the V + + + align:start position:0% +remember here we're setting the the V +the VC is what you're controlling as the + + align:start position:0% +the VC is what you're controlling as the + + + align:start position:0% +the VC is what you're controlling as the +experimenter you're setting the voltage + + align:start position:0% +experimenter you're setting the voltage + + + align:start position:0% +experimenter you're setting the voltage +with that command okay the current so + + align:start position:0% +with that command okay the current so + + + align:start position:0% +with that command okay the current so +the voltage clamp then holds the inside + + align:start position:0% +the voltage clamp then holds the inside + + + align:start position:0% +the voltage clamp then holds the inside +of the cell at that command voltage and + + align:start position:0% +of the cell at that command voltage and + + + align:start position:0% +of the cell at that command voltage and +then you're measuring the current with + + align:start position:0% +then you're measuring the current with + + + align:start position:0% +then you're measuring the current with +this device that there's a readout that + + align:start position:0% +this device that there's a readout that + + + align:start position:0% +this device that there's a readout that +tells you how much current it's putting + + align:start position:0% +tells you how much current it's putting + + + align:start position:0% +tells you how much current it's putting +into the cellar goes on to an + + align:start position:0% +into the cellar goes on to an + + + align:start position:0% +into the cellar goes on to an +oscilloscope because it's time dependent + + align:start position:0% +oscilloscope because it's time dependent + + + align:start position:0% +oscilloscope because it's time dependent +okay okay so let's do an experiment + + align:start position:0% +okay okay so let's do an experiment + + + align:start position:0% +okay okay so let's do an experiment +here's an example of an experiment they + + align:start position:0% +here's an example of an experiment they + + + align:start position:0% +here's an example of an experiment they +hold the command at minus 65 and + + align:start position:0% +hold the command at minus 65 and + + + align:start position:0% +hold the command at minus 65 and +suddenly they drop the command voltage + + align:start position:0% +suddenly they drop the command voltage + + + align:start position:0% +suddenly they drop the command voltage +to minus 130 what is the what is the + + align:start position:0% +to minus 130 what is the what is the + + + align:start position:0% +to minus 130 what is the what is the +cell do what is the current nothing okay + + align:start position:0% +cell do what is the current nothing okay + + + align:start position:0% +cell do what is the current nothing okay +there's a little transient here which is + + align:start position:0% +there's a little transient here which is + + + align:start position:0% +there's a little transient here which is +the amount of current it took to charge + + align:start position:0% +the amount of current it took to charge + + + align:start position:0% +the amount of current it took to charge +that capacitor up to minus 130 + + align:start position:0% +that capacitor up to minus 130 + + + align:start position:0% +that capacitor up to minus 130 +millivolts and then nothing happens + + align:start position:0% +millivolts and then nothing happens + + + align:start position:0% +millivolts and then nothing happens +all right let's do another experiment + + align:start position:0% +all right let's do another experiment + + + align:start position:0% +all right let's do another experiment +now we're going to take we're gonna + + align:start position:0% +now we're going to take we're gonna + + + align:start position:0% +now we're going to take we're gonna +start our cell at minus 65 and suddenly + + align:start position:0% +start our cell at minus 65 and suddenly + + + align:start position:0% +start our cell at minus 65 and suddenly +jump the voltage up to zero so we're + + align:start position:0% +jump the voltage up to zero so we're + + + align:start position:0% +jump the voltage up to zero so we're +gonna depolarize our cell and now + + align:start position:0% +gonna depolarize our cell and now + + + align:start position:0% +gonna depolarize our cell and now +something happens you get a big pulse of + + align:start position:0% +something happens you get a big pulse of + + + align:start position:0% +something happens you get a big pulse of +current that's negative what does + + align:start position:0% +current that's negative what does + + + align:start position:0% +current that's negative what does +negative mean anybody remember what + + align:start position:0% +negative mean anybody remember what + + + align:start position:0% +negative mean anybody remember what +negative current means by our definition + + align:start position:0% +negative current means by our definition + + + align:start position:0% +negative current means by our definition +negative means that there are positive + + align:start position:0% +negative means that there are positive + + + align:start position:0% +negative means that there are positive +ions going into the cell okay so it's + + align:start position:0% +ions going into the cell okay so it's + + + align:start position:0% +ions going into the cell okay so it's +charging the cell up okay this is + + align:start position:0% +charging the cell up okay this is + + + align:start position:0% +charging the cell up okay this is +membrane current now okay so you just + + align:start position:0% +membrane current now okay so you just + + + align:start position:0% +membrane current now okay so you just +have to remember that definition + + align:start position:0% +have to remember that definition + + + align:start position:0% +have to remember that definition +negative membrane current means that + + align:start position:0% +negative membrane current means that + + + align:start position:0% +negative membrane current means that +positive charges are going into the cell + + align:start position:0% +positive charges are going into the cell + + + align:start position:0% +positive charges are going into the cell +and that's chart that's depolarizing in + + align:start position:0% +and that's chart that's depolarizing in + + + align:start position:0% +and that's chart that's depolarizing in +the film okay and then that negative + + align:start position:0% +the film okay and then that negative + + + align:start position:0% +the film okay and then that negative +current lasts for a few milliseconds and + + align:start position:0% +current lasts for a few milliseconds and + + + align:start position:0% +current lasts for a few milliseconds and +then the current reverses sign and + + align:start position:0% +then the current reverses sign and + + + align:start position:0% +then the current reverses sign and +becomes positive and stays on okay so + + align:start position:0% +becomes positive and stays on okay so + + + align:start position:0% +becomes positive and stays on okay so +what is that so the first thing that + + align:start position:0% +what is that so the first thing that + + + align:start position:0% +what is that so the first thing that +hodgkin-huxley did was they tried to + + align:start position:0% +hodgkin-huxley did was they tried to + + + align:start position:0% +hodgkin-huxley did was they tried to +figure out what causes that pattern of + + align:start position:0% +figure out what causes that pattern of + + + align:start position:0% +figure out what causes that pattern of +currents okay so here's what they did + + align:start position:0% +currents okay so here's what they did + + + align:start position:0% +currents okay so here's what they did +they had this idea that part of this + + align:start position:0% +they had this idea that part of this + + + align:start position:0% +they had this idea that part of this +might be due to sodium and so what they + + align:start position:0% +might be due to sodium and so what they + + + align:start position:0% +might be due to sodium and so what they +did was they did an experiment where + + align:start position:0% +did was they did an experiment where + + + align:start position:0% +did was they did an experiment where +they were placed sodium outside the cell + + align:start position:0% +they were placed sodium outside the cell + + + align:start position:0% +they were placed sodium outside the cell +outside the axon with an ion with they + + align:start position:0% +outside the axon with an ion with they + + + align:start position:0% +outside the axon with an ion with they +replaced this they kept the chloride but + + align:start position:0% +replaced this they kept the chloride but + + + align:start position:0% +replaced this they kept the chloride but +they replaced the sodium with choline so + + align:start position:0% +they replaced the sodium with choline so + + + align:start position:0% +they replaced the sodium with choline so +they used choline chloride so it's a + + align:start position:0% +they used choline chloride so it's a + + + align:start position:0% +they used choline chloride so it's a +salt solution but it has no sodium in it + + align:start position:0% +salt solution but it has no sodium in it + + + align:start position:0% +salt solution but it has no sodium in it +and here's and then they redid that + + align:start position:0% +and here's and then they redid that + + + align:start position:0% +and here's and then they redid that +experiment and here's what they found + + align:start position:0% + + + + align:start position:0% + +what they found was so here it is with + + align:start position:0% +what they found was so here it is with + + + align:start position:0% +what they found was so here it is with +sodium and if they replace the sodium + + align:start position:0% +sodium and if they replace the sodium + + + align:start position:0% +sodium and if they replace the sodium +they find that they get almost the same + + align:start position:0% +they find that they get almost the same + + + align:start position:0% +they find that they get almost the same +thing except that initial negative pulse + + align:start position:0% +thing except that initial negative pulse + + + align:start position:0% +thing except that initial negative pulse +goes away okay so you can subtract and + + align:start position:0% +goes away okay so you can subtract and + + + align:start position:0% +goes away okay so you can subtract and +so they hypothesized that that part is + + align:start position:0% +so they hypothesized that that part is + + + align:start position:0% +so they hypothesized that that part is +due to sodium and so now you just + + align:start position:0% +due to sodium and so now you just + + + align:start position:0% +due to sodium and so now you just +subtract this from this to get the + + align:start position:0% +subtract this from this to get the + + + align:start position:0% +subtract this from this to get the +difference and that is the sodium + + align:start position:0% +difference and that is the sodium + + + align:start position:0% +difference and that is the sodium +current that makes sense okay so that's + + align:start position:0% +current that makes sense okay so that's + + + align:start position:0% +current that makes sense okay so that's +and then one other thing through another + + align:start position:0% +and then one other thing through another + + + align:start position:0% +and then one other thing through another +set of experiments they were able to + + align:start position:0% +set of experiments they were able to + + + align:start position:0% +set of experiments they were able to +show that this part that's left after + + align:start position:0% +show that this part that's left after + + + align:start position:0% +show that this part that's left after +you block or remove sodium is that due + + align:start position:0% +you block or remove sodium is that due + + + align:start position:0% +you block or remove sodium is that due +to potassium okay so this is the + + align:start position:0% +to potassium okay so this is the + + + align:start position:0% +to potassium okay so this is the +potassium current that is a sodium + + align:start position:0% +potassium current that is a sodium + + + align:start position:0% +potassium current that is a sodium +current okay so by doing different kinds + + align:start position:0% +current okay so by doing different kinds + + + align:start position:0% +current okay so by doing different kinds +of experiments so one of the things that + + align:start position:0% +of experiments so one of the things that + + + align:start position:0% +of experiments so one of the things that +you're able to do that they didn't do + + align:start position:0% +you're able to do that they didn't do + + + align:start position:0% +you're able to do that they didn't do +initially but later they were able to do + + align:start position:0% +initially but later they were able to do + + + align:start position:0% +initially but later they were able to do +things like take that little piece of + + align:start position:0% +things like take that little piece of + + + align:start position:0% +things like take that little piece of +axon take a little miniature paint + + align:start position:0% +axon take a little miniature paint + + + align:start position:0% +axon take a little miniature paint +roller squish the axon roll the roller + + align:start position:0% +roller squish the axon roll the roller + + + align:start position:0% +roller squish the axon roll the roller +over the axon squish its guts out and + + align:start position:0% +over the axon squish its guts out and + + + align:start position:0% +over the axon squish its guts out and +then fill it up again with solutions + + align:start position:0% +then fill it up again with solutions + + + align:start position:0% +then fill it up again with solutions +that they control that have different + + align:start position:0% +that they control that have different + + + align:start position:0% +that they control that have different +ions in them and so they're able to + + align:start position:0% +ions in them and so they're able to + + + align:start position:0% +ions in them and so they're able to +study you know just do multiple + + align:start position:0% +study you know just do multiple + + + align:start position:0% +study you know just do multiple +different kinds of experiments to be + + align:start position:0% +different kinds of experiments to be + + + align:start position:0% +different kinds of experiments to be +sure that this slow thing that turns on + + align:start position:0% +sure that this slow thing that turns on + + + align:start position:0% +sure that this slow thing that turns on +a slow positive current is potassium and + + align:start position:0% +a slow positive current is potassium and + + + align:start position:0% +a slow positive current is potassium and +this fast negative current is sodium all + + align:start position:0% +this fast negative current is sodium all + + + align:start position:0% +this fast negative current is sodium all +right okay so now what you can do is you + + align:start position:0% +right okay so now what you can do is you + + + align:start position:0% +right okay so now what you can do is you +can do this experiment at different + + align:start position:0% +can do this experiment at different + + + align:start position:0% +can do this experiment at different +voltages here right we want to measure + + align:start position:0% +voltages here right we want to measure + + + align:start position:0% +voltages here right we want to measure +how these currents depend on voltage + + align:start position:0% +how these currents depend on voltage + + + align:start position:0% +how these currents depend on voltage +right we can see here how they depend on + + align:start position:0% +right we can see here how they depend on + + + align:start position:0% +right we can see here how they depend on +time we can also see how they depend on + + align:start position:0% +time we can also see how they depend on + + + align:start position:0% +time we can also see how they depend on +voltage by doing this experiment at + + align:start position:0% +voltage by doing this experiment at + + + align:start position:0% +voltage by doing this experiment at +different voltages you start at some + + align:start position:0% +different voltages you start at some + + + align:start position:0% +different voltages you start at some +negative potential you step the voltage + + align:start position:0% +negative potential you step the voltage + + + align:start position:0% +negative potential you step the voltage +up to minus 40 or you step it up to zero + + align:start position:0% +up to minus 40 or you step it up to zero + + + align:start position:0% +up to minus 40 or you step it up to zero +or you step it up to 40 and now you can + + align:start position:0% +or you step it up to 40 and now you can + + + align:start position:0% +or you step it up to 40 and now you can +measure that potassium current as a + + align:start position:0% +measure that potassium current as a + + + align:start position:0% +measure that potassium current as a +function of time or the sodium current + + align:start position:0% +function of time or the sodium current + + + align:start position:0% +function of time or the sodium current +as a function of time + + align:start position:0% +as a function of time + + + align:start position:0% +as a function of time +all right at different voltages okay all + + align:start position:0% +all right at different voltages okay all + + + align:start position:0% +all right at different voltages okay all +right so those look kind of weird + + align:start position:0% +right so those look kind of weird + + + align:start position:0% +right so those look kind of weird +especially that one that looks kind of + + align:start position:0% +especially that one that looks kind of + + + align:start position:0% +especially that one that looks kind of +scary like what the heck is going on + + align:start position:0% +scary like what the heck is going on + + + align:start position:0% +scary like what the heck is going on +there okay but it turns out that both of + + align:start position:0% +there okay but it turns out that both of + + + align:start position:0% +there okay but it turns out that both of +both of these things are actually pretty + + align:start position:0% +both of these things are actually pretty + + + align:start position:0% +both of these things are actually pretty +simple once we dig a little bit more + + align:start position:0% +simple once we dig a little bit more + + + align:start position:0% +simple once we dig a little bit more +into into how these currents are + + align:start position:0% +into into how these currents are + + + align:start position:0% +into into how these currents are +produced you're gonna see that there's a + + align:start position:0% +produced you're gonna see that there's a + + + align:start position:0% +produced you're gonna see that there's a +very simple way to understand what + + align:start position:0% +very simple way to understand what + + + align:start position:0% +very simple way to understand what +what's happening there + + align:start position:0% +what's happening there + + + align:start position:0% +what's happening there +all right any questions they're with me + + align:start position:0% +all right any questions they're with me + + + align:start position:0% +all right any questions they're with me +okay so this so now what we want to do + + align:start position:0% +okay so this so now what we want to do + + + align:start position:0% +okay so this so now what we want to do +is we want to measure the voltage + + align:start position:0% +is we want to measure the voltage + + + align:start position:0% +is we want to measure the voltage +dependence of these things kind of + + align:start position:0% +dependence of these things kind of + + + align:start position:0% +dependence of these things kind of +separately from the time dependence so + + align:start position:0% +separately from the time dependence so + + + align:start position:0% +separately from the time dependence so +what we're gonna do is we're gonna + + align:start position:0% +what we're gonna do is we're gonna + + + align:start position:0% +what we're gonna do is we're gonna +measure the peak potassium current kind + + align:start position:0% +measure the peak potassium current kind + + + align:start position:0% +measure the peak potassium current kind +of this steady state seem current as a + + align:start position:0% +of this steady state seem current as a + + + align:start position:0% +of this steady state seem current as a +function of voltage okay so here's our + + align:start position:0% +function of voltage okay so here's our + + + align:start position:0% +function of voltage okay so here's our +IV curve that I promised that we were + + align:start position:0% +IV curve that I promised that we were + + + align:start position:0% +IV curve that I promised that we were +going to plot peak current as a function + + align:start position:0% +going to plot peak current as a function + + + align:start position:0% +going to plot peak current as a function +of voltage and you can see that it's + + align:start position:0% +of voltage and you can see that it's + + + align:start position:0% +of voltage and you can see that it's +approximately linear above minus 50 or + + align:start position:0% +approximately linear above minus 50 or + + + align:start position:0% +approximately linear above minus 50 or +so millivolts the sodium current looks + + align:start position:0% +so millivolts the sodium current looks + + + align:start position:0% +so millivolts the sodium current looks +kind of weird we're gonna plot the peak + + align:start position:0% +kind of weird we're gonna plot the peak + + + align:start position:0% +kind of weird we're gonna plot the peak +sodium current as a function of voltage + + align:start position:0% +sodium current as a function of voltage + + + align:start position:0% +sodium current as a function of voltage +and we see that the peak sodium current + + align:start position:0% +and we see that the peak sodium current + + + align:start position:0% +and we see that the peak sodium current +has this weird shape it's sort of linear + + align:start position:0% +has this weird shape it's sort of linear + + + align:start position:0% +has this weird shape it's sort of linear +up here at positive voltages and then it + + align:start position:0% +up here at positive voltages and then it + + + align:start position:0% +up here at positive voltages and then it +crashes down to zero I'd make all + + align:start position:0% +crashes down to zero I'd make all + + + align:start position:0% +crashes down to zero I'd make all +teachers okay all right still kind of + + align:start position:0% +teachers okay all right still kind of + + + align:start position:0% +teachers okay all right still kind of +weird and scary so let's see if we can + + align:start position:0% +weird and scary so let's see if we can + + + align:start position:0% +weird and scary so let's see if we can +understand where this comes from + + align:start position:0% +understand where this comes from + + + align:start position:0% +understand where this comes from +I just reap lotted them here so now + + align:start position:0% +I just reap lotted them here so now + + + align:start position:0% +I just reap lotted them here so now +remember that we use this voltage clamp + + align:start position:0% +remember that we use this voltage clamp + + + align:start position:0% +remember that we use this voltage clamp +to measure current as a voltage but what + + align:start position:0% +to measure current as a voltage but what + + + align:start position:0% +to measure current as a voltage but what +is it that we're really trying to + + align:start position:0% +is it that we're really trying to + + + align:start position:0% +is it that we're really trying to +understand we're really trying to + + align:start position:0% +understand we're really trying to + + + align:start position:0% +understand we're really trying to +understand the conductances those + + align:start position:0% +understand the conductances those + + + align:start position:0% +understand the conductances those +resistors but right we're under trying + + align:start position:0% +resistors but right we're under trying + + + align:start position:0% +resistors but right we're under trying +to understand the voltage and time + + align:start position:0% +to understand the voltage and time + + + align:start position:0% +to understand the voltage and time +dependence of those conductances all + + align:start position:0% +dependence of those conductances all + + + align:start position:0% +dependence of those conductances all +right so we're trying to extract + + align:start position:0% +right so we're trying to extract + + + align:start position:0% +right so we're trying to extract +conductance as a function of voltage and + + align:start position:0% +conductance as a function of voltage and + + + align:start position:0% +conductance as a function of voltage and +remember that + + align:start position:0% +remember that + + + align:start position:0% +remember that +it'sjust conductance times a driving + + align:start position:0% +it'sjust conductance times a driving + + + align:start position:0% +it'sjust conductance times a driving +potential for potassium sodium current + + align:start position:0% +potential for potassium sodium current + + + align:start position:0% +potential for potassium sodium current +is just sodium conductance times the + + align:start position:0% +is just sodium conductance times the + + + align:start position:0% +is just sodium conductance times the +sodium driving potential so we can + + align:start position:0% +sodium driving potential so we can + + + align:start position:0% +sodium driving potential so we can +extract inductance as current divided by + + align:start position:0% +extract inductance as current divided by + + + align:start position:0% +extract inductance as current divided by +the driving potential okay so that's + + align:start position:0% +the driving potential okay so that's + + + align:start position:0% +the driving potential okay so that's +this is what we're really trying to find + + align:start position:0% +this is what we're really trying to find + + + align:start position:0% +this is what we're really trying to find +rather than doing this rather than doing + + align:start position:0% +rather than doing this rather than doing + + + align:start position:0% +rather than doing this rather than doing +this division because this one over this + + align:start position:0% +this division because this one over this + + + align:start position:0% +this division because this one over this +thing goes to zero at the places where + + align:start position:0% +thing goes to zero at the places where + + + align:start position:0% +thing goes to zero at the places where +the voltage is equal to the equilibrium + + align:start position:0% +the voltage is equal to the equilibrium + + + align:start position:0% +the voltage is equal to the equilibrium +potential so we don't want to do that + + align:start position:0% +potential so we don't want to do that + + + align:start position:0% +potential so we don't want to do that +we're gonna solve this problem + + align:start position:0% +we're gonna solve this problem + + + align:start position:0% +we're gonna solve this problem +graphically so here's the driving + + align:start position:0% +graphically so here's the driving + + + align:start position:0% +graphically so here's the driving +potential right Li minus ek it goes to + + align:start position:0% +potential right Li minus ek it goes to + + + align:start position:0% +potential right Li minus ek it goes to +zero at minus at ek right and we want to + + align:start position:0% +zero at minus at ek right and we want to + + + align:start position:0% +zero at minus at ek right and we want to +find a conductance that makes this look + + align:start position:0% +find a conductance that makes this look + + + align:start position:0% +find a conductance that makes this look +like this so if this is kind of a + + align:start position:0% +like this so if this is kind of a + + + align:start position:0% +like this so if this is kind of a +straight line if the current as a + + align:start position:0% +straight line if the current as a + + + align:start position:0% +straight line if the current as a +function of voltage is kind of a + + align:start position:0% +function of voltage is kind of a + + + align:start position:0% +function of voltage is kind of a +straight line and this is a straight + + align:start position:0% +straight line and this is a straight + + + align:start position:0% +straight line and this is a straight +line what does that tell us about the + + align:start position:0% +line what does that tell us about the + + + align:start position:0% +line what does that tell us about the +conductance in this region up here it's + + align:start position:0% +conductance in this region up here it's + + + align:start position:0% +conductance in this region up here it's +constant excellent now if the if the + + align:start position:0% +constant excellent now if the if the + + + align:start position:0% +constant excellent now if the if the +driving potential is very negative here + + align:start position:0% +driving potential is very negative here + + + align:start position:0% +driving potential is very negative here +but the current is zero then what's the + + align:start position:0% +but the current is zero then what's the + + + align:start position:0% +but the current is zero then what's the +conductance driving potential is big and + + align:start position:0% +conductance driving potential is big and + + + align:start position:0% +conductance driving potential is big and +negative current is zero what does that + + align:start position:0% +negative current is zero what does that + + + align:start position:0% +negative current is zero what does that +tell us about the conductance it's zero + + align:start position:0% +tell us about the conductance it's zero + + + align:start position:0% +tell us about the conductance it's zero +okay so not not so hard right we have + + align:start position:0% +okay so not not so hard right we have + + + align:start position:0% +okay so not not so hard right we have +some 0 here and constant here so can + + align:start position:0% +some 0 here and constant here so can + + + align:start position:0% +some 0 here and constant here so can +anyone just show me what that might look + + align:start position:0% +anyone just show me what that might look + + + align:start position:0% +anyone just show me what that might look +like good it could be like a jump it + + align:start position:0% +like good it could be like a jump it + + + align:start position:0% +like good it could be like a jump it +could be kind of smooth and that's + + align:start position:0% +could be kind of smooth and that's + + + align:start position:0% +could be kind of smooth and that's +exactly what it looks like okay so the + + align:start position:0% +exactly what it looks like okay so the + + + align:start position:0% +exactly what it looks like okay so the +conductance is zero here which it has to + + align:start position:0% +conductance is zero here which it has to + + + align:start position:0% +conductance is zero here which it has to +be because the current is zero even the + + align:start position:0% +be because the current is zero even the + + + align:start position:0% +be because the current is zero even the +potential is negative and the + + align:start position:0% +potential is negative and the + + + align:start position:0% +potential is negative and the +conductance here is constant because the + + align:start position:0% +conductance here is constant because the + + + align:start position:0% +conductance here is constant because the +driving potential is constant here the + + align:start position:0% +driving potential is constant here the + + + align:start position:0% +driving potential is constant here the +driving potential is linear and the + + align:start position:0% +driving potential is linear and the + + + align:start position:0% +driving potential is linear and the +current is linear so this needs to be + + align:start position:0% +current is linear so this needs to be + + + align:start position:0% +current is linear so this needs to be +constant + + align:start position:0% +constant + + + align:start position:0% +constant +all right so the conductance is very + + align:start position:0% +all right so the conductance is very + + + align:start position:0% +all right so the conductance is very +simple it turns off at negative voltages + + align:start position:0% +simple it turns off at negative voltages + + + align:start position:0% +simple it turns off at negative voltages +and turns on and then stays on at higher + + align:start position:0% +and turns on and then stays on at higher + + + align:start position:0% +and turns on and then stays on at higher +voltages let's do that for sodium this + + align:start position:0% +voltages let's do that for sodium this + + + align:start position:0% +voltages let's do that for sodium this +thing looks crazy weird right but let's + + align:start position:0% +thing looks crazy weird right but let's + + + align:start position:0% +thing looks crazy weird right but let's +go through the same operation here's our + + align:start position:0% +go through the same operation here's our + + + align:start position:0% +go through the same operation here's our +driving potential for sodium remember + + align:start position:0% +driving potential for sodium remember + + + align:start position:0% +driving potential for sodium remember +it's got a reversal at plus 55 but it's + + align:start position:0% +it's got a reversal at plus 55 but it's + + + align:start position:0% +it's got a reversal at plus 55 but it's +it's a straight line right that's a + + align:start position:0% +it's a straight line right that's a + + + align:start position:0% +it's a straight line right that's a +battery and a resistor so there's our + + align:start position:0% +battery and a resistor so there's our + + + align:start position:0% +battery and a resistor so there's our +driving potential now this is linear + + align:start position:0% +driving potential now this is linear + + + align:start position:0% +driving potential now this is linear +this is linear so what does the + + align:start position:0% +this is linear so what does the + + + align:start position:0% +this is linear so what does the +conductance look like up here good this + + align:start position:0% +conductance look like up here good this + + + align:start position:0% +conductance look like up here good this +is zero but this is big and negative so + + align:start position:0% +is zero but this is big and negative so + + + align:start position:0% +is zero but this is big and negative so +what does this look like down here good + + align:start position:0% +what does this look like down here good + + + align:start position:0% +what does this look like down here good +starting to look pretty familiar right + + align:start position:0% +starting to look pretty familiar right + + + align:start position:0% +starting to look pretty familiar right +boom it's exactly the same both of these + + align:start position:0% +boom it's exactly the same both of these + + + align:start position:0% +boom it's exactly the same both of these +conductances are off at negative + + align:start position:0% +conductances are off at negative + + + align:start position:0% +conductances are off at negative +potentials and they turn on at positive + + align:start position:0% +potentials and they turn on at positive + + + align:start position:0% +potentials and they turn on at positive +voltages and remain constant okay yes + + align:start position:0% + + + + align:start position:0% + +great great question because the sodium + + align:start position:0% +great great question because the sodium + + + align:start position:0% +great great question because the sodium +conductance turns on and then it shuts + + align:start position:0% +conductance turns on and then it shuts + + + align:start position:0% +conductance turns on and then it shuts +off right away and the shutting off is a + + align:start position:0% +off right away and the shutting off is a + + + align:start position:0% +off right away and the shutting off is a +different mechanism so we're trying to + + align:start position:0% +different mechanism so we're trying to + + + align:start position:0% +different mechanism so we're trying to +figure out how to ignore that and just + + align:start position:0% +figure out how to ignore that and just + + + align:start position:0% +figure out how to ignore that and just +understand the voltage dependence of how + + align:start position:0% +understand the voltage dependence of how + + + align:start position:0% +understand the voltage dependence of how +it turns on does that make sense yeah + + align:start position:0% +it turns on does that make sense yeah + + + align:start position:0% +it turns on does that make sense yeah +and we'll get into that next Tuesday but + + align:start position:0% +and we'll get into that next Tuesday but + + + align:start position:0% +and we'll get into that next Tuesday but +I'm showing both of these at the same + + align:start position:0% +I'm showing both of these at the same + + + align:start position:0% +I'm showing both of these at the same +time because they they look Miller at + + align:start position:0% +time because they they look Miller at + + + align:start position:0% +time because they they look Miller at +the level of the voltage dependence in + + align:start position:0% +the level of the voltage dependence in + + + align:start position:0% +the level of the voltage dependence in +fact the way they turn on is very + + align:start position:0% +fact the way they turn on is very + + + align:start position:0% +fact the way they turn on is very +similar okay it's just that the sodium + + align:start position:0% +similar okay it's just that the sodium + + + align:start position:0% +similar okay it's just that the sodium +has some other weird thing that shuts it + + align:start position:0% +has some other weird thing that shuts it + + + align:start position:0% +has some other weird thing that shuts it +off after a few milliseconds so we'll + + align:start position:0% +off after a few milliseconds so we'll + + + align:start position:0% +off after a few milliseconds so we'll +talk about that next time yes + + align:start position:0% + + + + align:start position:0% + +nope it's not but any non-linearity here + + align:start position:0% +nope it's not but any non-linearity here + + + align:start position:0% +nope it's not but any non-linearity here +we're going to account for by changes by + + align:start position:0% +we're going to account for by changes by + + + align:start position:0% +we're going to account for by changes by +voltage dependence of the conductance + + align:start position:0% +voltage dependence of the conductance + + + align:start position:0% +voltage dependence of the conductance +okay so great point is that a subtlety + + align:start position:0% +okay so great point is that a subtlety + + + align:start position:0% +okay so great point is that a subtlety +that that we have kind of imposed by + + align:start position:0% +that that we have kind of imposed by + + + align:start position:0% +that that we have kind of imposed by +this way of writing down the voltage + + align:start position:0% +this way of writing down the voltage + + + align:start position:0% +this way of writing down the voltage +dependence of the of the current any + + align:start position:0% +dependence of the of the current any + + + align:start position:0% +dependence of the of the current any +other questions no okay + + align:start position:0% +other questions no okay + + + align:start position:0% +other questions no okay +pushing on so this kind of gradual + + align:start position:0% +pushing on so this kind of gradual + + + align:start position:0% +pushing on so this kind of gradual +turning on this sort of zero conductance + + align:start position:0% +turning on this sort of zero conductance + + + align:start position:0% +turning on this sort of zero conductance +down here and a constants up here that's + + align:start position:0% +down here and a constants up here that's + + + align:start position:0% +down here and a constants up here that's +called a sigmoid volvulus + + align:start position:0% +called a sigmoid volvulus + + + align:start position:0% +called a sigmoid volvulus +it's how these channels turn on okay and + + align:start position:0% +it's how these channels turn on okay and + + + align:start position:0% +it's how these channels turn on okay and +as I said before we're going to deal + + align:start position:0% +as I said before we're going to deal + + + align:start position:0% +as I said before we're going to deal +with how they the other properties of + + align:start position:0% +with how they the other properties of + + + align:start position:0% +with how they the other properties of +the sodium channel that turn it off + + align:start position:0% +the sodium channel that turn it off + + + align:start position:0% +the sodium channel that turn it off +later so both have a sigmoidal voltage + + align:start position:0% +later so both have a sigmoidal voltage + + + align:start position:0% +later so both have a sigmoidal voltage +dependence of activation okay and if you + + align:start position:0% +dependence of activation okay and if you + + + align:start position:0% +dependence of activation okay and if you +plot this you can see that if you plot + + align:start position:0% +plot this you can see that if you plot + + + align:start position:0% +plot this you can see that if you plot +this on a on a log scale here log scale + + align:start position:0% +this on a on a log scale here log scale + + + align:start position:0% +this on a on a log scale here log scale +on conductance linear here on potential + + align:start position:0% +on conductance linear here on potential + + + align:start position:0% +on conductance linear here on potential +you can see that both of these curves + + align:start position:0% +you can see that both of these curves + + + align:start position:0% +you can see that both of these curves +both the potassium and the sodium have + + align:start position:0% +both the potassium and the sodium have + + + align:start position:0% +both the potassium and the sodium have +this very characteristic exponential + + align:start position:0% +this very characteristic exponential + + + align:start position:0% +this very characteristic exponential +turn on followed by this saturation a + + align:start position:0% +turn on followed by this saturation a + + + align:start position:0% +turn on followed by this saturation a +constant constant conductance at higher + + align:start position:0% +constant constant conductance at higher + + + align:start position:0% +constant constant conductance at higher +voltages alright any questions that's + + align:start position:0% +voltages alright any questions that's + + + align:start position:0% +voltages alright any questions that's +voltage dependence now we're going to + + align:start position:0% +voltage dependence now we're going to + + + align:start position:0% +voltage dependence now we're going to +turn to time dependence okay so you can + + align:start position:0% +turn to time dependence okay so you can + + + align:start position:0% +turn to time dependence okay so you can +see that the time dependence so this + + align:start position:0% +see that the time dependence so this + + + align:start position:0% +see that the time dependence so this +driving potential that's just constant + + align:start position:0% +driving potential that's just constant + + + align:start position:0% +driving potential that's just constant +that just depends on the voltage and the + + align:start position:0% +that just depends on the voltage and the + + + align:start position:0% +that just depends on the voltage and the +reversal potential and so we can + + align:start position:0% +reversal potential and so we can + + + align:start position:0% +reversal potential and so we can +separate out that that this thing is + + align:start position:0% +separate out that that this thing is + + + align:start position:0% +separate out that that this thing is +just any time dependence this has is + + align:start position:0% +just any time dependence this has is + + + align:start position:0% +just any time dependence this has is +dependent on the time dependence of the + + align:start position:0% +dependent on the time dependence of the + + + align:start position:0% +dependent on the time dependence of the +voltage but in our in our voltage clamp + + align:start position:0% +voltage but in our in our voltage clamp + + + align:start position:0% +voltage but in our in our voltage clamp +experiments the voltage is constant so + + align:start position:0% +experiments the voltage is constant so + + + align:start position:0% +experiments the voltage is constant so +this thing is constant so anytime + + align:start position:0% +this thing is constant so anytime + + + align:start position:0% +this thing is constant so anytime +Penance current has to be due to time + + align:start position:0% +Penance current has to be due to time + + + align:start position:0% +Penance current has to be due to time +dependence of the conductance right and + + align:start position:0% +dependence of the conductance right and + + + align:start position:0% +dependence of the conductance right and +what that means is we can just look at + + align:start position:0% +what that means is we can just look at + + + align:start position:0% +what that means is we can just look at +the shape of this potassium current + + align:start position:0% +the shape of this potassium current + + + align:start position:0% +the shape of this potassium current +remember this is the potassium current + + align:start position:0% +remember this is the potassium current + + + align:start position:0% +remember this is the potassium current +here that time dependence is just due to + + align:start position:0% +here that time dependence is just due to + + + align:start position:0% +here that time dependence is just due to +time dependence of the conductance that + + align:start position:0% +time dependence of the conductance that + + + align:start position:0% +time dependence of the conductance that +makes sense + + align:start position:0% +makes sense + + + align:start position:0% +makes sense +so what's happening is the potassium + + align:start position:0% +so what's happening is the potassium + + + align:start position:0% +so what's happening is the potassium +conductance is starting at zero the + + align:start position:0% +conductance is starting at zero the + + + align:start position:0% +conductance is starting at zero the +moment you step the voltage up that + + align:start position:0% +moment you step the voltage up that + + + align:start position:0% +moment you step the voltage up that +thing begins to grow gradually and then + + align:start position:0% +thing begins to grow gradually and then + + + align:start position:0% +thing begins to grow gradually and then +runs up to a constant potassium + + align:start position:0% +runs up to a constant potassium + + + align:start position:0% +runs up to a constant potassium +conductance in time it starts off ramps + + align:start position:0% +conductance in time it starts off ramps + + + align:start position:0% +conductance in time it starts off ramps +up and then becomes constant alright so + + align:start position:0% +up and then becomes constant alright so + + + align:start position:0% +up and then becomes constant alright so +that's the time dependence alright sort + + align:start position:0% +that's the time dependence alright sort + + + align:start position:0% +that's the time dependence alright sort +of gracefully turns on that process of + + align:start position:0% +of gracefully turns on that process of + + + align:start position:0% +of gracefully turns on that process of +turning on is called activation the + + align:start position:0% +turning on is called activation the + + + align:start position:0% +turning on is called activation the +sodium conductance their current the + + align:start position:0% +sodium conductance their current the + + + align:start position:0% +sodium conductance their current the +same thing the sodium current is just + + align:start position:0% +same thing the sodium current is just + + + align:start position:0% +same thing the sodium current is just +the sodium conductance the sodium + + align:start position:0% +the sodium conductance the sodium + + + align:start position:0% +the sodium conductance the sodium +current as a function is the sodium + + align:start position:0% +current as a function is the sodium + + + align:start position:0% +current as a function is the sodium +conductance as a function of time times + + align:start position:0% +conductance as a function of time times + + + align:start position:0% +conductance as a function of time times +a constant in our voltage clamp + + align:start position:0% +a constant in our voltage clamp + + + align:start position:0% +a constant in our voltage clamp +experiment again this voltage is + + align:start position:0% +experiment again this voltage is + + + align:start position:0% +experiment again this voltage is +constant so that the sodium conductance + + align:start position:0% +constant so that the sodium conductance + + + align:start position:0% +constant so that the sodium conductance +turns on + + align:start position:0% +turns on + + + align:start position:0% +turns on +that's activation but then it turns off + + align:start position:0% +that's activation but then it turns off + + + align:start position:0% +that's activation but then it turns off +and that's called inactivation all right + + align:start position:0% +and that's called inactivation all right + + + align:start position:0% +and that's called inactivation all right +so the sodium current has but in + + align:start position:0% +so the sodium current has but in + + + align:start position:0% +so the sodium current has but in +conductance has two things going on + + align:start position:0% +conductance has two things going on + + + align:start position:0% +conductance has two things going on +one activation and the second is + + align:start position:0% +one activation and the second is + + + align:start position:0% +one activation and the second is +inactivation okay and it turns out these + + align:start position:0% +inactivation okay and it turns out these + + + align:start position:0% +inactivation okay and it turns out these +are two separate biophysical mechanisms + + align:start position:0% +are two separate biophysical mechanisms + + + align:start position:0% +are two separate biophysical mechanisms +and we're gonna spend more time on this + + align:start position:0% +and we're gonna spend more time on this + + + align:start position:0% +and we're gonna spend more time on this +next week okay so + + align:start position:0% +next week okay so + + + align:start position:0% +next week okay so +notice something interesting the sodium + + align:start position:0% +notice something interesting the sodium + + + align:start position:0% +notice something interesting the sodium +conductance turns on you depolarize the + + align:start position:0% +conductance turns on you depolarize the + + + align:start position:0% +conductance turns on you depolarize the +cell sodium conductance turns on right + + align:start position:0% +cell sodium conductance turns on right + + + align:start position:0% +cell sodium conductance turns on right +away and then shuts off the potassium + + align:start position:0% +away and then shuts off the potassium + + + align:start position:0% +away and then shuts off the potassium +conductance has a delay and then it + + align:start position:0% +conductance has a delay and then it + + + align:start position:0% +conductance has a delay and then it +turns on does that look familiar that + + align:start position:0% +turns on does that look familiar that + + + align:start position:0% +turns on does that look familiar that +looks an awful lot like like this right + + align:start position:0% +looks an awful lot like like this right + + + align:start position:0% +looks an awful lot like like this right +here's the sodium conductance turns on + + align:start position:0% +here's the sodium conductance turns on + + + align:start position:0% +here's the sodium conductance turns on +and then shuts off and then the + + align:start position:0% +and then shuts off and then the + + + align:start position:0% +and then shuts off and then the +potassium conductance turns on with a + + align:start position:0% +potassium conductance turns on with a + + + align:start position:0% +potassium conductance turns on with a +delay yeah and that gives us an action + + align:start position:0% +delay yeah and that gives us an action + + + align:start position:0% +delay yeah and that gives us an action +potential so you can see that when you + + align:start position:0% +potential so you can see that when you + + + align:start position:0% +potential so you can see that when you +use voltage clamp and to sect it out the + + align:start position:0% +use voltage clamp and to sect it out the + + + align:start position:0% +use voltage clamp and to sect it out the +tightness of the of the sodium and + + align:start position:0% +tightness of the of the sodium and + + + align:start position:0% +tightness of the of the sodium and +potassium conductance it looks just like + + align:start position:0% +potassium conductance it looks just like + + + align:start position:0% +potassium conductance it looks just like +the thing we concocted earlier just sort + + align:start position:0% +the thing we concocted earlier just sort + + + align:start position:0% +the thing we concocted earlier just sort +of a toy example for how to make an + + align:start position:0% +of a toy example for how to make an + + + align:start position:0% +of a toy example for how to make an +action potential pretty cool right okay + + align:start position:0% +action potential pretty cool right okay + + + align:start position:0% +action potential pretty cool right okay +it's starting to come together piece by + + align:start position:0% +it's starting to come together piece by + + + align:start position:0% +it's starting to come together piece by +piece + + align:start position:0% + + + + align:start position:0% + +okay so we're now going to dig in a + + align:start position:0% +okay so we're now going to dig in a + + + align:start position:0% +okay so we're now going to dig in a +little bit deeper into the biophysics of + + align:start position:0% +little bit deeper into the biophysics of + + + align:start position:0% +little bit deeper into the biophysics of +how you get these voltage and time + + align:start position:0% +how you get these voltage and time + + + align:start position:0% +how you get these voltage and time +dependencies okay so we're going to + + align:start position:0% +dependencies okay so we're going to + + + align:start position:0% +dependencies okay so we're going to +derive the equation for the voltage + + align:start position:0% +derive the equation for the voltage + + + align:start position:0% +derive the equation for the voltage +dependence anybody want to take a crazy + + align:start position:0% +dependence anybody want to take a crazy + + + align:start position:0% +dependence anybody want to take a crazy +guess on how we're gonna do that just a + + align:start position:0% +guess on how we're gonna do that just a + + + align:start position:0% +guess on how we're gonna do that just a +wild guess how you might derive the + + align:start position:0% +wild guess how you might derive the + + + align:start position:0% +wild guess how you might derive the +voltage dependence of something No okay + + align:start position:0% +voltage dependence of something No okay + + + align:start position:0% +voltage dependence of something No okay +we're gonna use the Boltzmann equation + + align:start position:0% + + + + align:start position:0% + +and we're gonna derive different + + align:start position:0% +and we're gonna derive different + + + align:start position:0% +and we're gonna derive different +equations that describe the way those + + align:start position:0% +equations that describe the way those + + + align:start position:0% +equations that describe the way those +channels turn on okay how those + + align:start position:0% +channels turn on okay how those + + + align:start position:0% +channels turn on okay how those +conductances turn on alright and once we + + align:start position:0% +conductances turn on alright and once we + + + align:start position:0% +conductances turn on alright and once we +do that we're gonna have a simple set of + + align:start position:0% +do that we're gonna have a simple set of + + + align:start position:0% +do that we're gonna have a simple set of +equations and not just equations we're + + align:start position:0% +equations and not just equations we're + + + align:start position:0% +equations and not just equations we're +gonna have a set of processes that we + + align:start position:0% +gonna have a set of processes that we + + + align:start position:0% +gonna have a set of processes that we +can think of as happening a loop in a + + align:start position:0% +can think of as happening a loop in a + + + align:start position:0% +can think of as happening a loop in a +for loop that's our algorithm for an + + align:start position:0% +for loop that's our algorithm for an + + + align:start position:0% +for loop that's our algorithm for an +action potential okay all right so let's + + align:start position:0% +action potential okay all right so let's + + + align:start position:0% +action potential okay all right so let's +dive into single channels and see see + + align:start position:0% +dive into single channels and see see + + + align:start position:0% +dive into single channels and see see +how they worked so of course + + align:start position:0% +how they worked so of course + + + align:start position:0% +how they worked so of course +currents are result from ionic flow + + align:start position:0% +currents are result from ionic flow + + + align:start position:0% +currents are result from ionic flow +through ion channels it's actually + + align:start position:0% +through ion channels it's actually + + + align:start position:0% +through ion channels it's actually +possible to record currents from single + + align:start position:0% +possible to record currents from single + + + align:start position:0% +possible to record currents from single +ion channels we can actually make a + + align:start position:0% +ion channels we can actually make a + + + align:start position:0% +ion channels we can actually make a +version of our voltage clamp that we can + + align:start position:0% +version of our voltage clamp that we can + + + align:start position:0% +version of our voltage clamp that we can +attach to a single ion channel and the + + align:start position:0% +attach to a single ion channel and the + + + align:start position:0% +attach to a single ion channel and the +way you do that is it's so when you take + + align:start position:0% +way you do that is it's so when you take + + + align:start position:0% +way you do that is it's so when you take +this piece of glass and you pull it + + align:start position:0% +this piece of glass and you pull it + + + align:start position:0% +this piece of glass and you pull it +instead of poking it through the cell + + align:start position:0% +instead of poking it through the cell + + + align:start position:0% +instead of poking it through the cell +instead of making it really sharp and + + align:start position:0% +instead of making it really sharp and + + + align:start position:0% +instead of making it really sharp and +poking it through the cell what you do + + align:start position:0% +poking it through the cell what you do + + + align:start position:0% +poking it through the cell what you do +is you make it a little bit blunter okay + + align:start position:0% +is you make it a little bit blunter okay + + + align:start position:0% +is you make it a little bit blunter okay +so it's got kind of a rough end and then + + align:start position:0% +so it's got kind of a rough end and then + + + align:start position:0% +so it's got kind of a rough end and then +you can fire polish you can hold the end + + align:start position:0% +you can fire polish you can hold the end + + + align:start position:0% +you can fire polish you can hold the end +of that electrode into a flame okay + + align:start position:0% +of that electrode into a flame okay + + + align:start position:0% +of that electrode into a flame okay +quite it's usually a filament that heats + + align:start position:0% +quite it's usually a filament that heats + + + align:start position:0% +quite it's usually a filament that heats +up hot you hold the end of the electrode + + align:start position:0% +up hot you hold the end of the electrode + + + align:start position:0% +up hot you hold the end of the electrode +near this hot and it melts the tip into + + align:start position:0% +near this hot and it melts the tip into + + + align:start position:0% +near this hot and it melts the tip into +a nice round it's still a tube but the + + align:start position:0% +a nice round it's still a tube but the + + + align:start position:0% +a nice round it's still a tube but the +edges of the tube are nice and smooth + + align:start position:0% +edges of the tube are nice and smooth + + + align:start position:0% +edges of the tube are nice and smooth +okay and now when you take that tube and + + align:start position:0% +okay and now when you take that tube and + + + align:start position:0% +okay and now when you take that tube and +you press it up against the cell + + align:start position:0% +you press it up against the cell + + + align:start position:0% +you press it up against the cell +actually you attach all + + align:start position:0% +actually you attach all + + + align:start position:0% +actually you attach all +a little plastic tube to the end of the + + align:start position:0% +a little plastic tube to the end of the + + + align:start position:0% +a little plastic tube to the end of the +glass and you press the the electrode + + align:start position:0% +glass and you press the the electrode + + + align:start position:0% +glass and you press the the electrode +it's the selling you actually you + + align:start position:0% +it's the selling you actually you + + + align:start position:0% +it's the selling you actually you +literally suck on it with your mouth + + align:start position:0% +literally suck on it with your mouth + + + align:start position:0% +literally suck on it with your mouth +onto that tube and it sucks the membrane + + align:start position:0% +onto that tube and it sucks the membrane + + + align:start position:0% +onto that tube and it sucks the membrane +up against that smooth end of the + + align:start position:0% +up against that smooth end of the + + + align:start position:0% +up against that smooth end of the +electrode and it sticks the lipids of + + align:start position:0% +electrode and it sticks the lipids of + + + align:start position:0% +electrode and it sticks the lipids of +the membrane actually sealed themselves + + align:start position:0% +the membrane actually sealed themselves + + + align:start position:0% +the membrane actually sealed themselves +onto the end of the glass so now no + + align:start position:0% +onto the end of the glass so now no + + + align:start position:0% +onto the end of the glass so now no +currents can flow out through the + + align:start position:0% +currents can flow out through the + + + align:start position:0% +currents can flow out through the +through these edges here all right and + + align:start position:0% +through these edges here all right and + + + align:start position:0% +through these edges here all right and +then you hook it up to a very sensitive + + align:start position:0% +then you hook it up to a very sensitive + + + align:start position:0% +then you hook it up to a very sensitive +current amplifier and now you can + + align:start position:0% +current amplifier and now you can + + + align:start position:0% +current amplifier and now you can +control the voltage you can actually + + align:start position:0% +control the voltage you can actually + + + align:start position:0% +control the voltage you can actually +just rip that off of the cell so now + + align:start position:0% +just rip that off of the cell so now + + + align:start position:0% +just rip that off of the cell so now +there's no more cell you just have an + + align:start position:0% +there's no more cell you just have an + + + align:start position:0% +there's no more cell you just have an +ion channel sitting there on a piece and + + align:start position:0% +ion channel sitting there on a piece and + + + align:start position:0% +ion channel sitting there on a piece and +the end of your glass and now you can do + + align:start position:0% +the end of your glass and now you can do + + + align:start position:0% +the end of your glass and now you can do +a voltage clamp experiment and study the + + align:start position:0% +a voltage clamp experiment and study the + + + align:start position:0% +a voltage clamp experiment and study the +current the voltage dependence of the + + align:start position:0% +current the voltage dependence of the + + + align:start position:0% +current the voltage dependence of the +current through that ion channel so + + align:start position:0% +current through that ion channel so + + + align:start position:0% +current through that ion channel so +here's what this looks like here's one + + align:start position:0% +here's what this looks like here's one + + + align:start position:0% +here's what this looks like here's one +experiment we're gonna start at minus + + align:start position:0% +experiment we're gonna start at minus + + + align:start position:0% +experiment we're gonna start at minus +100 this is a potassium channel you + + align:start position:0% +100 this is a potassium channel you + + + align:start position:0% +100 this is a potassium channel you +depolarize the potassium channel up to + + align:start position:0% +depolarize the potassium channel up to + + + align:start position:0% +depolarize the potassium channel up to +50 millivolts and you see that the + + align:start position:0% +50 millivolts and you see that the + + + align:start position:0% +50 millivolts and you see that the +current through that single channel + + align:start position:0% +current through that single channel + + + align:start position:0% +current through that single channel +starts flickering on and off okay here's + + align:start position:0% +starts flickering on and off okay here's + + + align:start position:0% +starts flickering on and off okay here's +another trial turns on turns off turns + + align:start position:0% +another trial turns on turns off turns + + + align:start position:0% +another trial turns on turns off turns +on turns off you can do that a bunch of + + align:start position:0% +on turns off you can do that a bunch of + + + align:start position:0% +on turns off you can do that a bunch of +times you can see something interesting + + align:start position:0% +times you can see something interesting + + + align:start position:0% +times you can see something interesting +the current is either off doesn't turn + + align:start position:0% +the current is either off doesn't turn + + + align:start position:0% +the current is either off doesn't turn +on gradually doesn't change smoothly it + + align:start position:0% +on gradually doesn't change smoothly it + + + align:start position:0% +on gradually doesn't change smoothly it +just flickers between on and off it's a + + align:start position:0% +just flickers between on and off it's a + + + align:start position:0% +just flickers between on and off it's a +very important aspect of ion channels + + align:start position:0% +very important aspect of ion channels + + + align:start position:0% +very important aspect of ion channels +but if you average all those trials + + align:start position:0% +but if you average all those trials + + + align:start position:0% +but if you average all those trials +together you see that you get an average + + align:start position:0% +together you see that you get an average + + + align:start position:0% +together you see that you get an average +current that looks just like the current + + align:start position:0% +current that looks just like the current + + + align:start position:0% +current that looks just like the current +that hodgkin-huxley measured in the + + align:start position:0% +that hodgkin-huxley measured in the + + + align:start position:0% +that hodgkin-huxley measured in the +whole axon how is that possible + + align:start position:0% + + + + align:start position:0% + +yeah good so basically what we're doing + + align:start position:0% +yeah good so basically what we're doing + + + align:start position:0% +yeah good so basically what we're doing +is we're measuring one ion channel many + + align:start position:0% +is we're measuring one ion channel many + + + align:start position:0% +is we're measuring one ion channel many +times but on a cell you're measuring a + + align:start position:0% +times but on a cell you're measuring a + + + align:start position:0% +times but on a cell you're measuring a +bunch of ion channels each of which is + + align:start position:0% +bunch of ion channels each of which is + + + align:start position:0% +bunch of ion channels each of which is +doing something like this but there have + + align:start position:0% +doing something like this but there have + + + align:start position:0% +doing something like this but there have +at the same time and the current is + + align:start position:0% +at the same time and the current is + + + align:start position:0% +at the same time and the current is +being averaged so here we're averaging + + align:start position:0% +being averaged so here we're averaging + + + align:start position:0% +being averaged so here we're averaging +the current one at a time and on a whole + + align:start position:0% +the current one at a time and on a whole + + + align:start position:0% +the current one at a time and on a whole +cell were just averaging a bunch of them + + align:start position:0% +cell were just averaging a bunch of them + + + align:start position:0% +cell were just averaging a bunch of them +at once okay it's called ergot disa T in + + align:start position:0% +at once okay it's called ergot disa T in + + + align:start position:0% +at once okay it's called ergot disa T in +physics that's called the ensemble + + align:start position:0% +physics that's called the ensemble + + + align:start position:0% +physics that's called the ensemble +average okay you can do the same thing + + align:start position:0% +average okay you can do the same thing + + + align:start position:0% +average okay you can do the same thing +for sodium you take your patch a new + + align:start position:0% +for sodium you take your patch a new + + + align:start position:0% +for sodium you take your patch a new +patch electrode fire polish it push it + + align:start position:0% +patch electrode fire polish it push it + + + align:start position:0% +patch electrode fire polish it push it +up to a cell by some suction glues on + + align:start position:0% +up to a cell by some suction glues on + + + align:start position:0% +up to a cell by some suction glues on +this time we had a sodium channel okay + + align:start position:0% +this time we had a sodium channel okay + + + align:start position:0% +this time we had a sodium channel okay +and now you can see that the thing again + + align:start position:0% +and now you can see that the thing again + + + align:start position:0% +and now you can see that the thing again +flickers on flickers flickers on + + align:start position:0% +flickers on flickers flickers on + + + align:start position:0% +flickers on flickers flickers on +flickers off but now they all flicker on + + align:start position:0% +flickers off but now they all flicker on + + + align:start position:0% +flickers off but now they all flicker on +right at the beginning and then they + + align:start position:0% +right at the beginning and then they + + + align:start position:0% +right at the beginning and then they +flicker off and stay off and if you + + align:start position:0% +flicker off and stay off and if you + + + align:start position:0% +flicker off and stay off and if you +average all those different trials you + + align:start position:0% +average all those different trials you + + + align:start position:0% +average all those different trials you +see an average an ensemble average + + align:start position:0% +see an average an ensemble average + + + align:start position:0% +see an average an ensemble average +sodium current that looks just like when + + align:start position:0% +sodium current that looks just like when + + + align:start position:0% +sodium current that looks just like when +you measure the sodium current on a + + align:start position:0% +you measure the sodium current on a + + + align:start position:0% +you measure the sodium current on a +whole act okay but the key thing is that + + align:start position:0% +whole act okay but the key thing is that + + + align:start position:0% +whole act okay but the key thing is that +these channels have two states on and + + align:start position:0% +these channels have two states on and + + + align:start position:0% +these channels have two states on and +off and they flicker back and forth + + align:start position:0% +off and they flicker back and forth + + + align:start position:0% +off and they flicker back and forth +between those two states conducting and + + align:start position:0% +between those two states conducting and + + + align:start position:0% +between those two states conducting and +non conducting so we can now write down + + align:start position:0% +non conducting so we can now write down + + + align:start position:0% +non conducting so we can now write down +we could start now working with this + + align:start position:0% +we could start now working with this + + + align:start position:0% +we could start now working with this +idea that our ion channels are eating + + align:start position:0% +idea that our ion channels are eating + + + align:start position:0% +idea that our ion channels are eating +open or closed and we can think of a + + align:start position:0% +open or closed and we can think of a + + + align:start position:0% +open or closed and we can think of a +probability that the channel is being + + align:start position:0% +probability that the channel is being + + + align:start position:0% +probability that the channel is being +open that the channel is open we can + + align:start position:0% +open that the channel is open we can + + + align:start position:0% +open that the channel is open we can +have a total number of channels the + + align:start position:0% +have a total number of channels the + + + align:start position:0% +have a total number of channels the +probability the number of open channels + + align:start position:0% +probability the number of open channels + + + align:start position:0% +probability the number of open channels +is just the number of channels you have + + align:start position:0% +is just the number of channels you have + + + align:start position:0% +is just the number of channels you have +times the probability that any one of + + align:start position:0% +times the probability that any one of + + + align:start position:0% +times the probability that any one of +them is open if G is the conductance of + + align:start position:0% +them is open if G is the conductance of + + + align:start position:0% +them is open if G is the conductance of +one open channel then we can write down + + align:start position:0% +one open channel then we can write down + + + align:start position:0% +one open channel then we can write down +the total potassium conductance as the + + align:start position:0% +the total potassium conductance as the + + + align:start position:0% +the total potassium conductance as the +probability that any given ion channel + + align:start position:0% +probability that any given ion channel + + + align:start position:0% +probability that any given ion channel +is open times the number of channels + + align:start position:0% +is open times the number of channels + + + align:start position:0% +is open times the number of channels +times the conductance of one open + + align:start position:0% +times the conductance of one open + + + align:start position:0% +times the conductance of one open +channel + + align:start position:0% +channel + + + align:start position:0% +channel +there makes sense and now to claim here + + align:start position:0% +there makes sense and now to claim here + + + align:start position:0% +there makes sense and now to claim here +all of the interesting voltage and time + + align:start position:0% +all of the interesting voltage and time + + + align:start position:0% +all of the interesting voltage and time +dependence of these channels happens + + align:start position:0% +dependence of these channels happens + + + align:start position:0% +dependence of these channels happens +here obviously the number of them isn't + + align:start position:0% +here obviously the number of them isn't + + + align:start position:0% +here obviously the number of them isn't +changing very rapidly the conductance + + align:start position:0% +changing very rapidly the conductance + + + align:start position:0% +changing very rapidly the conductance +per channel is constant per open channel + + align:start position:0% +per channel is constant per open channel + + + align:start position:0% +per channel is constant per open channel +so the interesting stuff is in the + + align:start position:0% +so the interesting stuff is in the + + + align:start position:0% +so the interesting stuff is in the +probability that the channel okay and + + align:start position:0% +probability that the channel okay and + + + align:start position:0% +probability that the channel okay and +when we want to get the current we're + + align:start position:0% +when we want to get the current we're + + + align:start position:0% +when we want to get the current we're +just going to plug this conductance into + + align:start position:0% +just going to plug this conductance into + + + align:start position:0% +just going to plug this conductance into +here okay all right so let's start with + + align:start position:0% +here okay all right so let's start with + + + align:start position:0% +here okay all right so let's start with +a potassium channel let's dig in a + + align:start position:0% +a potassium channel let's dig in a + + + align:start position:0% +a potassium channel let's dig in a +little bit deeper into what the + + align:start position:0% +little bit deeper into what the + + + align:start position:0% +little bit deeper into what the +potassium channel looks like potassium + + align:start position:0% +potassium channel looks like potassium + + + align:start position:0% +potassium channel looks like potassium +channel is formed by four identical + + align:start position:0% +channel is formed by four identical + + + align:start position:0% +channel is formed by four identical +subunits there they're produced + + align:start position:0% +subunits there they're produced + + + align:start position:0% +subunits there they're produced +separately by by ribosomes they they + + align:start position:0% +separately by by ribosomes they they + + + align:start position:0% +separately by by ribosomes they they +form a heterodimer a tetramer + + align:start position:0% +form a heterodimer a tetramer + + + align:start position:0% +form a heterodimer a tetramer +and that tetra mer has a hole that runs + + align:start position:0% +and that tetra mer has a hole that runs + + + align:start position:0% +and that tetra mer has a hole that runs +down the middle of it which is where the + + align:start position:0% +down the middle of it which is where the + + + align:start position:0% +down the middle of it which is where the +where the ions flow each of these + + align:start position:0% +where the ions flow each of these + + + align:start position:0% +where the ions flow each of these +subunits has a voltage sensor that + + align:start position:0% +subunits has a voltage sensor that + + + align:start position:0% +subunits has a voltage sensor that +allows it to turn on and off and in + + align:start position:0% +allows it to turn on and off and in + + + align:start position:0% +allows it to turn on and off and in +order for the channel to be on all four + + align:start position:0% +order for the channel to be on all four + + + align:start position:0% +order for the channel to be on all four +of those subunits has to be open so each + + align:start position:0% +of those subunits has to be open so each + + + align:start position:0% +of those subunits has to be open so each +subunit has an open state and a closed + + align:start position:0% +subunit has an open state and a closed + + + align:start position:0% +subunit has an open state and a closed +state and for the channel to be open all + + align:start position:0% +state and for the channel to be open all + + + align:start position:0% +state and for the channel to be open all +four of them have to be in the open + + align:start position:0% +four of them have to be in the open + + + align:start position:0% +four of them have to be in the open +state okay + + align:start position:0% + + + + align:start position:0% + +so if n is the probability that any one + + align:start position:0% +so if n is the probability that any one + + + align:start position:0% +so if n is the probability that any one +subunit is open I meant to ask me make + + align:start position:0% +subunit is open I meant to ask me make + + + align:start position:0% +subunit is open I meant to ask me make +you guys answer this question before I + + align:start position:0% +you guys answer this question before I + + + align:start position:0% +you guys answer this question before I +show the answer but is it clear how if + + align:start position:0% +show the answer but is it clear how if + + + align:start position:0% +show the answer but is it clear how if +any one subunit has a probability of + + align:start position:0% +any one subunit has a probability of + + + align:start position:0% +any one subunit has a probability of +being open of n then the probability + + align:start position:0% +being open of n then the probability + + + align:start position:0% +being open of n then the probability +that the whole channel is open is n to + + align:start position:0% +that the whole channel is open is n to + + + align:start position:0% +that the whole channel is open is n to +the four okay this n is called a gating + + align:start position:0% +the four okay this n is called a gating + + + align:start position:0% +the four okay this n is called a gating +variable I would like you to be able to + + align:start position:0% +variable I would like you to be able to + + + align:start position:0% +variable I would like you to be able to +I would like you to know that the + + align:start position:0% +I would like you to know that the + + + align:start position:0% +I would like you to know that the +probability that a sodium potassium + + align:start position:0% +probability that a sodium potassium + + + align:start position:0% +probability that a sodium potassium +channel is open is n to the four that's + + align:start position:0% +channel is open is n to the four that's + + + align:start position:0% +channel is open is n to the four that's +an important thing for you to remember + + align:start position:0% +an important thing for you to remember + + + align:start position:0% +an important thing for you to remember +that assumes that those four subunits + + align:start position:0% +that assumes that those four subunits + + + align:start position:0% +that assumes that those four subunits +are independent okay and in potassium + + align:start position:0% +are independent okay and in potassium + + + align:start position:0% +are independent okay and in potassium +channels that's a very good + + align:start position:0% +channels that's a very good + + + align:start position:0% +channels that's a very good +approximation so we can now write down + + align:start position:0% +approximation so we can now write down + + + align:start position:0% +approximation so we can now write down +the conductance of our potassium channel + + align:start position:0% +the conductance of our potassium channel + + + align:start position:0% +the conductance of our potassium channel +something times n to the 4 where that + + align:start position:0% +something times n to the 4 where that + + + align:start position:0% +something times n to the 4 where that +something is that conductance of 1 ion + + align:start position:0% +something is that conductance of 1 ion + + + align:start position:0% +something is that conductance of 1 ion +channel okay so we can now write down + + align:start position:0% +channel okay so we can now write down + + + align:start position:0% +channel okay so we can now write down +the current as n open conductance times + + align:start position:0% +the current as n open conductance times + + + align:start position:0% +the current as n open conductance times +n to the 4 times a driving potential and + + align:start position:0% +n to the 4 times a driving potential and + + + align:start position:0% +n to the 4 times a driving potential and +that n is called the gating variable for + + align:start position:0% +that n is called the gating variable for + + + align:start position:0% +that n is called the gating variable for +the potassium conductance all right any + + align:start position:0% +the potassium conductance all right any + + + align:start position:0% +the potassium conductance all right any +questions no yes and absolutely does + + align:start position:0% +questions no yes and absolutely does + + + align:start position:0% +questions no yes and absolutely does +depend on voltage very good that's where + + align:start position:0% +depend on voltage very good that's where + + + align:start position:0% +depend on voltage very good that's where +we're going next okay okay but before we + + align:start position:0% +we're going next okay okay but before we + + + align:start position:0% +we're going next okay okay but before we +go on to that I want to do one other + + align:start position:0% +go on to that I want to do one other + + + align:start position:0% +go on to that I want to do one other +thing which I think is is really cool + + align:start position:0% +thing which I think is is really cool + + + align:start position:0% +thing which I think is is really cool +we're gonna do the voltage dependence of + + align:start position:0% +we're gonna do the voltage dependence of + + + align:start position:0% +we're gonna do the voltage dependence of +a potassium channel using the Boltzmann + + align:start position:0% +a potassium channel using the Boltzmann + + + align:start position:0% +a potassium channel using the Boltzmann +equation okay + + align:start position:0% +equation okay + + + align:start position:0% +equation okay +so here's the way you think about a + + align:start position:0% +so here's the way you think about a + + + align:start position:0% +so here's the way you think about a +potassium channel working here's a + + align:start position:0% +potassium channel working here's a + + + align:start position:0% +potassium channel working here's a +potassium channel we're showing a + + align:start position:0% +potassium channel we're showing a + + + align:start position:0% +potassium channel we're showing a +cross-section here it is here's the + + align:start position:0% +cross-section here it is here's the + + + align:start position:0% +cross-section here it is here's the +membrane the lipid bilayer here's our + + align:start position:0% +membrane the lipid bilayer here's our + + + align:start position:0% +membrane the lipid bilayer here's our +potassium channel sitting in the in the + + align:start position:0% +potassium channel sitting in the in the + + + align:start position:0% +potassium channel sitting in the in the +membrane and we're taking a + + align:start position:0% +membrane and we're taking a + + + align:start position:0% +membrane and we're taking a +cross-section through that tetramer that + + align:start position:0% +cross-section through that tetramer that + + + align:start position:0% +cross-section through that tetramer that +shows two subunits and I'm showing the + + align:start position:0% +shows two subunits and I'm showing the + + + align:start position:0% +shows two subunits and I'm showing the +voltage sent of showing the mechanism + + align:start position:0% +voltage sent of showing the mechanism + + + align:start position:0% +voltage sent of showing the mechanism +that that opens and closes one of those + + align:start position:0% +that that opens and closes one of those + + + align:start position:0% +that that opens and closes one of those +subunits okay this this subunit will + + align:start position:0% +subunits okay this this subunit will + + + align:start position:0% +subunits okay this this subunit will +also have a voltage sensor and a gate + + align:start position:0% +also have a voltage sensor and a gate + + + align:start position:0% +also have a voltage sensor and a gate +that looks the same okay so look the + + align:start position:0% +that looks the same okay so look the + + + align:start position:0% +that looks the same okay so look the +voltage sensor how do you sense voltage + + align:start position:0% +voltage sensor how do you sense voltage + + + align:start position:0% +voltage sensor how do you sense voltage +you sense voltage with charge right + + align:start position:0% +you sense voltage with charge right + + + align:start position:0% +you sense voltage with charge right +voltage + + align:start position:0% + + + + align:start position:0% + +differences I should say you sense with + + align:start position:0% +differences I should say you sense with + + + align:start position:0% +differences I should say you sense with +a charge because voltage gradients are + + align:start position:0% +a charge because voltage gradients are + + + align:start position:0% +a charge because voltage gradients are +electric fields and electric fields push + + align:start position:0% +electric fields and electric fields push + + + align:start position:0% +electric fields and electric fields push +on charges so if we want to detect the + + align:start position:0% +on charges so if we want to detect the + + + align:start position:0% +on charges so if we want to detect the +voltage difference across this membrane + + align:start position:0% +voltage difference across this membrane + + + align:start position:0% +voltage difference across this membrane +we put a charge in the membrane when the + + align:start position:0% +we put a charge in the membrane when the + + + align:start position:0% +we put a charge in the membrane when the +voltage difference is zero there's + + align:start position:0% +voltage difference is zero there's + + + align:start position:0% +voltage difference is zero there's +little force on the on those charges now + + align:start position:0% +little force on the on those charges now + + + align:start position:0% +little force on the on those charges now +if we suddenly hyperpolarize the cell so + + align:start position:0% +if we suddenly hyperpolarize the cell so + + + align:start position:0% +if we suddenly hyperpolarize the cell so +it's very negative + + align:start position:0% +it's very negative + + + align:start position:0% +it's very negative +now there's an electric field inside the + + align:start position:0% +now there's an electric field inside the + + + align:start position:0% +now there's an electric field inside the +membrane that points toward the inside + + align:start position:0% +membrane that points toward the inside + + + align:start position:0% +membrane that points toward the inside +of the cell which pushes those charges + + align:start position:0% +of the cell which pushes those charges + + + align:start position:0% +of the cell which pushes those charges +toward the inside of the cell and now + + align:start position:0% +toward the inside of the cell and now + + + align:start position:0% +toward the inside of the cell and now +you can just have a little mechanical + + align:start position:0% +you can just have a little mechanical + + + align:start position:0% +you can just have a little mechanical +linkage that's not really what it looks + + align:start position:0% +linkage that's not really what it looks + + + align:start position:0% +linkage that's not really what it looks +like but there's some consumnes is in + + align:start position:0% +like but there's some consumnes is in + + + align:start position:0% +like but there's some consumnes is in +the protein are configured so that when + + align:start position:0% +the protein are configured so that when + + + align:start position:0% +the protein are configured so that when +those charges get pushed on it closes a + + align:start position:0% +those charges get pushed on it closes a + + + align:start position:0% +those charges get pushed on it closes a +gate and now that current can no longer + + align:start position:0% +gate and now that current can no longer + + + align:start position:0% +gate and now that current can no longer +flow through the ion channel okay + + align:start position:0% + + + + align:start position:0% + +okay so now we're gonna derive how this + + align:start position:0% +okay so now we're gonna derive how this + + + align:start position:0% +okay so now we're gonna derive how this +we're gonna see how to derive this + + align:start position:0% +we're gonna see how to derive this + + + align:start position:0% +we're gonna see how to derive this +voltage dependence from the Boltzmann + + align:start position:0% +voltage dependence from the Boltzmann + + + align:start position:0% +voltage dependence from the Boltzmann +equation alright so everybody this is + + align:start position:0% +equation alright so everybody this is + + + align:start position:0% +equation alright so everybody this is +just for fun I don't to know how to do + + align:start position:0% +just for fun I don't to know how to do + + + align:start position:0% +just for fun I don't to know how to do +this I just want you to see it because I + + align:start position:0% +this I just want you to see it because I + + + align:start position:0% +this I just want you to see it because I +personally get chills when I see this + + align:start position:0% +personally get chills when I see this + + + align:start position:0% +personally get chills when I see this +it's really cool but I'm not expecting + + align:start position:0% +it's really cool but I'm not expecting + + + align:start position:0% +it's really cool but I'm not expecting +you to be able to reproduce it okay + + align:start position:0% +you to be able to reproduce it okay + + + align:start position:0% +you to be able to reproduce it okay +so just watch okay so again the + + align:start position:0% +so just watch okay so again the + + + align:start position:0% +so just watch okay so again the +Boltzmann equation says that the + + align:start position:0% +Boltzmann equation says that the + + + align:start position:0% +Boltzmann equation says that the +probability of being in two states open + + align:start position:0% +probability of being in two states open + + + align:start position:0% +probability of being in two states open +or closed depends on the energy + + align:start position:0% +or closed depends on the energy + + + align:start position:0% +or closed depends on the energy +difference between them okay so we have + + align:start position:0% +difference between them okay so we have + + + align:start position:0% +difference between them okay so we have +an open state and a closed state and + + align:start position:0% +an open state and a closed state and + + + align:start position:0% +an open state and a closed state and +when the voltage inside the cell is zero + + align:start position:0% +when the voltage inside the cell is zero + + + align:start position:0% +when the voltage inside the cell is zero +when the voltage difference between the + + align:start position:0% +when the voltage difference between the + + + align:start position:0% +when the voltage difference between the +inside and the outside cell of the cell + + align:start position:0% +inside and the outside cell of the cell + + + align:start position:0% +inside and the outside cell of the cell +is zero you know that the sodium channel + + align:start position:0% +is zero you know that the sodium channel + + + align:start position:0% +is zero you know that the sodium channel +likes to be open so what that means is + + align:start position:0% +likes to be open so what that means is + + + align:start position:0% +likes to be open so what that means is +that the open state has a lower energy + + align:start position:0% +that the open state has a lower energy + + + align:start position:0% +that the open state has a lower energy +than the closed state right sodium + + align:start position:0% +than the closed state right sodium + + + align:start position:0% +than the closed state right sodium +channel likes to open when the cell is + + align:start position:0% +channel likes to open when the cell is + + + align:start position:0% +channel likes to open when the cell is +depolarize that means the voltage inside + + align:start position:0% +depolarize that means the voltage inside + + + align:start position:0% +depolarize that means the voltage inside +and outside are close to each other + + align:start position:0% +and outside are close to each other + + + align:start position:0% +and outside are close to each other +right open state has a lower energy than + + align:start position:0% +right open state has a lower energy than + + + align:start position:0% +right open state has a lower energy than +the closed State let's call that energy + + align:start position:0% +the closed State let's call that energy + + + align:start position:0% +the closed State let's call that energy +difference Delta U okay and it's close + + align:start position:0% +difference Delta U okay and it's close + + + align:start position:0% +difference Delta U okay and it's close +to KT because when it's open this cell + + align:start position:0% +to KT because when it's open this cell + + + align:start position:0% +to KT because when it's open this cell +kind of the channel kind of flickers + + align:start position:0% +kind of the channel kind of flickers + + + align:start position:0% +kind of the channel kind of flickers +back and forth between open and closed + + align:start position:0% +back and forth between open and closed + + + align:start position:0% +back and forth between open and closed +that makes sense okay now now let's put + + align:start position:0% +that makes sense okay now now let's put + + + align:start position:0% +that makes sense okay now now let's put +on let's hyperpolarize the inside of our + + align:start position:0% +on let's hyperpolarize the inside of our + + + align:start position:0% +on let's hyperpolarize the inside of our +cells so now the voltage inside is low + + align:start position:0% +cells so now the voltage inside is low + + + align:start position:0% +cells so now the voltage inside is low +there's a voltage gradient an electric + + align:start position:0% +there's a voltage gradient an electric + + + align:start position:0% +there's a voltage gradient an electric +field that that is is trying to push + + align:start position:0% +field that that is is trying to push + + + align:start position:0% +field that that is is trying to push +those charges in now you can see that + + align:start position:0% +those charges in now you can see that + + + align:start position:0% +those charges in now you can see that +those charges here are sitting at a + + align:start position:0% +those charges here are sitting at a + + + align:start position:0% +those charges here are sitting at a +lower voltage so in the close date those + + align:start position:0% +lower voltage so in the close date those + + + align:start position:0% +lower voltage so in the close date those +charges are down here at a lower + + align:start position:0% +charges are down here at a lower + + + align:start position:0% +charges are down here at a lower +potential what does that mean for the + + align:start position:0% +potential what does that mean for the + + + align:start position:0% +potential what does that mean for the +energy of the closed State when the cell + + align:start position:0% +energy of the closed State when the cell + + + align:start position:0% +energy of the closed State when the cell +is hyperpolarized it's lower right the + + align:start position:0% +is hyperpolarized it's lower right the + + + align:start position:0% +is hyperpolarized it's lower right the +energy of the closed State is low + + align:start position:0% +energy of the closed State is low + + + align:start position:0% +energy of the closed State is low +because those charges are + + align:start position:0% +because those charges are + + + align:start position:0% +because those charges are +toward the inside of the cell and then + + align:start position:0% +toward the inside of the cell and then + + + align:start position:0% +toward the inside of the cell and then +and the voltage is low okay now what + + align:start position:0% +and the voltage is low okay now what + + + align:start position:0% +and the voltage is low okay now what +happens if the cell is hyperpolarized + + align:start position:0% +happens if the cell is hyperpolarized + + + align:start position:0% +happens if the cell is hyperpolarized +but it happens to be in the open state + + align:start position:0% +but it happens to be in the open state + + + align:start position:0% +but it happens to be in the open state +you can see those charges are closer + + align:start position:0% +you can see those charges are closer + + + align:start position:0% +you can see those charges are closer +this way so that you can see that the + + align:start position:0% +this way so that you can see that the + + + align:start position:0% +this way so that you can see that the +energy of these these charges are still + + align:start position:0% +energy of these these charges are still + + + align:start position:0% +energy of these these charges are still +sitting in a voltage that's lower than + + align:start position:0% +sitting in a voltage that's lower than + + + align:start position:0% +sitting in a voltage that's lower than +outside so that open state has a + + align:start position:0% +outside so that open state has a + + + align:start position:0% +outside so that open state has a +slightly lower energy but you can see + + align:start position:0% +slightly lower energy but you can see + + + align:start position:0% +slightly lower energy but you can see +that the closed state still has a much + + align:start position:0% +that the closed state still has a much + + + align:start position:0% +that the closed state still has a much +lower energy than the open state okay + + align:start position:0% +lower energy than the open state okay + + + align:start position:0% +lower energy than the open state okay +and we can write down that voltage + + align:start position:0% +and we can write down that voltage + + + align:start position:0% +and we can write down that voltage +difference as a gating charge times this + + align:start position:0% +difference as a gating charge times this + + + align:start position:0% +difference as a gating charge times this +voltage prints okay so now let's just + + align:start position:0% +voltage prints okay so now let's just + + + align:start position:0% +voltage prints okay so now let's just +take here's it an open state that has an + + align:start position:0% +take here's it an open state that has an + + + align:start position:0% +take here's it an open state that has an +energy difference of a little a little + + align:start position:0% +energy difference of a little a little + + + align:start position:0% +energy difference of a little a little +amount W open state is lower than close + + align:start position:0% +amount W open state is lower than close + + + align:start position:0% +amount W open state is lower than close +by an amount W when the voltage inside + + align:start position:0% +by an amount W when the voltage inside + + + align:start position:0% +by an amount W when the voltage inside +the cell is low we've decreased the + + align:start position:0% +the cell is low we've decreased the + + + align:start position:0% +the cell is low we've decreased the +energy of the closed state by this + + align:start position:0% +energy of the closed state by this + + + align:start position:0% +energy of the closed state by this +amount gating charge times membrane + + align:start position:0% +amount gating charge times membrane + + + align:start position:0% +amount gating charge times membrane +potential okay and now we have an energy + + align:start position:0% +potential okay and now we have an energy + + + align:start position:0% +potential okay and now we have an energy +difference in the open State and the + + align:start position:0% +difference in the open State and the + + + align:start position:0% +difference in the open State and the +close the energy difference between the + + align:start position:0% +close the energy difference between the + + + align:start position:0% +close the energy difference between the +open state and closed state as a + + align:start position:0% +open state and closed state as a + + + align:start position:0% +open state and closed state as a +function of voltage yes we have a simple + + align:start position:0% +function of voltage yes we have a simple + + + align:start position:0% +function of voltage yes we have a simple +equation that describes the energy + + align:start position:0% +equation that describes the energy + + + align:start position:0% +equation that describes the energy +difference between the open and closed + + align:start position:0% +difference between the open and closed + + + align:start position:0% +difference between the open and closed +State as a function of the membrane + + align:start position:0% +State as a function of the membrane + + + align:start position:0% +State as a function of the membrane +potential and now we can just plug that + + align:start position:0% +potential and now we can just plug that + + + align:start position:0% +potential and now we can just plug that +into the Boltzmann equation and derive + + align:start position:0% +into the Boltzmann equation and derive + + + align:start position:0% +into the Boltzmann equation and derive +the probability of being open and closed + + align:start position:0% +the probability of being open and closed + + + align:start position:0% +the probability of being open and closed +okay so we just plug that Delta u into + + align:start position:0% +okay so we just plug that Delta u into + + + align:start position:0% +okay so we just plug that Delta u into +here w- gating charge times voltage now + + align:start position:0% +here w- gating charge times voltage now + + + align:start position:0% +here w- gating charge times voltage now +let's calculate the probability of being + + align:start position:0% +let's calculate the probability of being + + + align:start position:0% +let's calculate the probability of being +open this gives us the ratio of open to + + align:start position:0% +open this gives us the ratio of open to + + + align:start position:0% +open this gives us the ratio of open to +closed how do we calculate the + + align:start position:0% +closed how do we calculate the + + + align:start position:0% +closed how do we calculate the +probability of being open well n is the + + align:start position:0% +probability of being open well n is the + + + align:start position:0% +probability of being open well n is the +probability of being open that's just + + align:start position:0% +probability of being open that's just + + + align:start position:0% +probability of being open that's just +probably open / open + closed + + align:start position:0% +probably open / open + closed + + + align:start position:0% +probably open / open + closed +what's probability of being open + + + align:start position:0% +what's probability of being open + + + + align:start position:0% +what's probability of being open + +probability being closed well if it's it + + align:start position:0% +probability being closed well if it's it + + + align:start position:0% +probability being closed well if it's it +if it's in one or the other then the sum + + align:start position:0% +if it's in one or the other then the sum + + + align:start position:0% +if it's in one or the other then the sum +of those has to be one okay + + align:start position:0% + + + + align:start position:0% + +and now divide both side top and bottom + + align:start position:0% +and now divide both side top and bottom + + + align:start position:0% +and now divide both side top and bottom +by P not the probability of being open + + align:start position:0% +by P not the probability of being open + + + align:start position:0% +by P not the probability of being open +is just 1 over 1 plus P closed over P + + align:start position:0% +is just 1 over 1 plus P closed over P + + + align:start position:0% +is just 1 over 1 plus P closed over P +open which is just the inverse of this + + align:start position:0% +open which is just the inverse of this + + + align:start position:0% +open which is just the inverse of this +and that's equal to that okay all right + + align:start position:0% +and that's equal to that okay all right + + + align:start position:0% +and that's equal to that okay all right +that may have gone by a little bit too + + align:start position:0% +that may have gone by a little bit too + + + align:start position:0% +that may have gone by a little bit too +fast and I wasn't very smooth on that + + align:start position:0% +fast and I wasn't very smooth on that + + + align:start position:0% +fast and I wasn't very smooth on that +you can see the idea right it's about + + align:start position:0% +you can see the idea right it's about + + + align:start position:0% +you can see the idea right it's about +estimating it's estimating how the + + align:start position:0% +estimating it's estimating how the + + + align:start position:0% +estimating it's estimating how the +energy difference between the open and + + align:start position:0% +energy difference between the open and + + + align:start position:0% +energy difference between the open and +closed state depends on the voltage of + + align:start position:0% +closed state depends on the voltage of + + + align:start position:0% +closed state depends on the voltage of +the cell and it's just an energy + + align:start position:0% +the cell and it's just an energy + + + align:start position:0% +the cell and it's just an energy +difference so it has to be a charge + + align:start position:0% +difference so it has to be a charge + + + align:start position:0% +difference so it has to be a charge +times a voltage yeah and that's right + + align:start position:0% +times a voltage yeah and that's right + + + align:start position:0% +times a voltage yeah and that's right +charge times a voltage and now we're + + align:start position:0% +charge times a voltage and now we're + + + align:start position:0% +charge times a voltage and now we're +just doing a little bit of algebra to + + align:start position:0% +just doing a little bit of algebra to + + + align:start position:0% +just doing a little bit of algebra to +extract probability of open from open + + align:start position:0% +extract probability of open from open + + + align:start position:0% +extract probability of open from open +divided by closed okay and and now if we + + align:start position:0% +divided by closed okay and and now if we + + + align:start position:0% +divided by closed okay and and now if we +just plug that into there we get this + + align:start position:0% +just plug that into there we get this + + + align:start position:0% +just plug that into there we get this +alright so now let's see how that + + align:start position:0% +alright so now let's see how that + + + align:start position:0% +alright so now let's see how that +compares to the actual answer + + align:start position:0% +compares to the actual answer + + + align:start position:0% +compares to the actual answer +probability of open it's just 1 over e 1 + + align:start position:0% +probability of open it's just 1 over e 1 + + + align:start position:0% +probability of open it's just 1 over e 1 +1 over 1 plus this exponential here's + + align:start position:0% +1 over 1 plus this exponential here's + + + align:start position:0% +1 over 1 plus this exponential here's +what that data looked like remember that + + align:start position:0% +what that data looked like remember that + + + align:start position:0% +what that data looked like remember that +was the data for the open product for + + align:start position:0% +was the data for the open product for + + + align:start position:0% +was the data for the open product for +the conductance as a function of voltage + + align:start position:0% + + + + align:start position:0% + +here's a fit to a functional form that + + align:start position:0% +here's a fit to a functional form that + + + align:start position:0% +here's a fit to a functional form that +looks like that and here is the + + align:start position:0% +looks like that and here is the + + + align:start position:0% +looks like that and here is the +prediction from Boltzmann ok you can see + + align:start position:0% +prediction from Boltzmann ok you can see + + + align:start position:0% +prediction from Boltzmann ok you can see +that it almost exactly fits and you can + + align:start position:0% +that it almost exactly fits and you can + + + align:start position:0% +that it almost exactly fits and you can +actually extract biophysically what the + + align:start position:0% +actually extract biophysically what the + + + align:start position:0% +actually extract biophysically what the +gating charges inside this tiny little + + align:start position:0% +gating charges inside this tiny little + + + align:start position:0% +gating charges inside this tiny little +protein simply by looking by fitting + + align:start position:0% +protein simply by looking by fitting + + + align:start position:0% +protein simply by looking by fitting +this to the data okay pretty cool right + + align:start position:0% +this to the data okay pretty cool right + + + align:start position:0% +this to the data okay pretty cool right +yes W is it's the energy difference + + align:start position:0% +yes W is it's the energy difference + + + align:start position:0% +yes W is it's the energy difference +between the open and closed state when + + align:start position:0% +between the open and closed state when + + + align:start position:0% +between the open and closed state when +the voltage is 0 so you kind of have to + + align:start position:0% +the voltage is 0 so you kind of have to + + + align:start position:0% +the voltage is 0 so you kind of have to +fit that too okay it's it's + + align:start position:0% +fit that too okay it's it's + + + align:start position:0% +fit that too okay it's it's +voltage is zero it's the it's the energy + + align:start position:0% +voltage is zero it's the it's the energy + + + align:start position:0% +voltage is zero it's the it's the energy +difference between the open and closed + + align:start position:0% +difference between the open and closed + + + align:start position:0% +difference between the open and closed +state when the voltage is zero okay and + + align:start position:0% +state when the voltage is zero okay and + + + align:start position:0% +state when the voltage is zero okay and +then you subtract from that the energy + + align:start position:0% +then you subtract from that the energy + + + align:start position:0% +then you subtract from that the energy +of the gating charge as a function of + + align:start position:0% +of the gating charge as a function of + + + align:start position:0% +of the gating charge as a function of +voltage inside the cell okay + + align:start position:0% + + + + align:start position:0% + +yes yes each has the sensor and they all + + align:start position:0% +yes yes each has the sensor and they all + + + align:start position:0% +yes yes each has the sensor and they all +have to be open for the ion channel to + + align:start position:0% +have to be open for the ion channel to + + + align:start position:0% +have to be open for the ion channel to +be open yes nope because this is the + + align:start position:0% +be open yes nope because this is the + + + align:start position:0% +be open yes nope because this is the +problem that one subunit is open yeah + + align:start position:0% +problem that one subunit is open yeah + + + align:start position:0% +problem that one subunit is open yeah +but that's a good point if you want to + + align:start position:0% +but that's a good point if you want to + + + align:start position:0% +but that's a good point if you want to +compare that to the okay so you're right + + align:start position:0% +compare that to the okay so you're right + + + align:start position:0% +compare that to the okay so you're right +if you want to compared it that to the + + align:start position:0% +if you want to compared it that to the + + + align:start position:0% +if you want to compared it that to the +conductance of the whole channel then it + + align:start position:0% +conductance of the whole channel then it + + + align:start position:0% +conductance of the whole channel then it +has to be raised to the power of four + + align:start position:0% +has to be raised to the power of four + + + align:start position:0% +has to be raised to the power of four +and that's been accounted for here good + + align:start position:0% +and that's been accounted for here good + + + align:start position:0% +and that's been accounted for here good +good question any other questions + + align:start position:0% +good question any other questions + + + align:start position:0% +good question any other questions +Boltzmann equation is pretty cool if you + + align:start position:0% +Boltzmann equation is pretty cool if you + + + align:start position:0% +Boltzmann equation is pretty cool if you +if you know the the mass of a nitrogen + + align:start position:0% +if you know the the mass of a nitrogen + + + align:start position:0% +if you know the the mass of a nitrogen +molecule and acceleration due to gravity + + align:start position:0% +molecule and acceleration due to gravity + + + align:start position:0% +molecule and acceleration due to gravity +what can you calculate with the + + align:start position:0% +what can you calculate with the + + + align:start position:0% +what can you calculate with the +Boltzmann equation any idea the mass of + + align:start position:0% +Boltzmann equation any idea the mass of + + + align:start position:0% +Boltzmann equation any idea the mass of +a nitrogen molecule and the acceleration + + align:start position:0% +a nitrogen molecule and the acceleration + + + align:start position:0% +a nitrogen molecule and the acceleration +due to gravity close you can calculate + + align:start position:0% +due to gravity close you can calculate + + + align:start position:0% +due to gravity close you can calculate +the height of the atmosphere you do all + + align:start position:0% +the height of the atmosphere you do all + + + align:start position:0% +the height of the atmosphere you do all +kinds of really cool stuff with the + + align:start position:0% +kinds of really cool stuff with the + + + align:start position:0% +kinds of really cool stuff with the +Boltzmann equation + + align:start position:0% + + + + align:start position:0% + +okay there was another question here no + + align:start position:0% +okay there was another question here no + + + align:start position:0% +okay there was another question here no +okay okay so you can extract actually + + align:start position:0% +okay okay so you can extract actually + + + align:start position:0% +okay okay so you can extract actually +these quantities the gating charge and + + align:start position:0% +these quantities the gating charge and + + + align:start position:0% +these quantities the gating charge and +this energy difference in the zero + + align:start position:0% +this energy difference in the zero + + + align:start position:0% +this energy difference in the zero +voltage state okay so and the fit is + + align:start position:0% +voltage state okay so and the fit is + + + align:start position:0% +voltage state okay so and the fit is +very good okay so that's voltage + + align:start position:0% +very good okay so that's voltage + + + align:start position:0% +very good okay so that's voltage +dependence I highlighted these slides + + align:start position:0% +dependence I highlighted these slides + + + align:start position:0% +dependence I highlighted these slides +that I don't expect you to be able to + + align:start position:0% +that I don't expect you to be able to + + + align:start position:0% +that I don't expect you to be able to +you know to reproduce in blue okay so + + align:start position:0% +you know to reproduce in blue okay so + + + align:start position:0% +you know to reproduce in blue okay so +you can just make it more clear what you + + align:start position:0% +you can just make it more clear what you + + + align:start position:0% +you can just make it more clear what you +know for your review what you have to + + align:start position:0% +know for your review what you have to + + + align:start position:0% +know for your review what you have to +focus on okay let's look at the time + + align:start position:0% +focus on okay let's look at the time + + + align:start position:0% +focus on okay let's look at the time +dependence the time dependence is pretty + + align:start position:0% +dependence the time dependence is pretty + + + align:start position:0% +dependence the time dependence is pretty +simple it's going to just involve a + + align:start position:0% +simple it's going to just involve a + + + align:start position:0% +simple it's going to just involve a +linear first order differential equation + + align:start position:0% +linear first order differential equation + + + align:start position:0% +linear first order differential equation +you guys are all like super experts on + + align:start position:0% +you guys are all like super experts on + + + align:start position:0% +you guys are all like super experts on +that now right okay so we have an ion + + align:start position:0% +that now right okay so we have an ion + + + align:start position:0% +that now right okay so we have an ion +channel sorry a subunit that's either + + align:start position:0% +channel sorry a subunit that's either + + + align:start position:0% +channel sorry a subunit that's either +open or closed right we have an open + + align:start position:0% +open or closed right we have an open + + + align:start position:0% +open or closed right we have an open +state closed state what we're gonna do + + align:start position:0% +state closed state what we're gonna do + + + align:start position:0% +state closed state what we're gonna do +is so the way to think about this is the + + align:start position:0% +is so the way to think about this is the + + + align:start position:0% +is so the way to think about this is the +ion channel the subunit if the cell is + + align:start position:0% +ion channel the subunit if the cell is + + + align:start position:0% +ion channel the subunit if the cell is +hyperpolarized is sitting in the closed + + align:start position:0% +hyperpolarized is sitting in the closed + + + align:start position:0% +hyperpolarized is sitting in the closed +State right when you depolarize the + + align:start position:0% +State right when you depolarize the + + + align:start position:0% +State right when you depolarize the +neuron that changes the energy levels so + + align:start position:0% +neuron that changes the energy levels so + + + align:start position:0% +neuron that changes the energy levels so +which way wasn't I forget okay the + + align:start position:0% +which way wasn't I forget okay the + + + align:start position:0% +which way wasn't I forget okay the +closed state has a lower energy now when + + align:start position:0% +closed state has a lower energy now when + + + align:start position:0% +closed state has a lower energy now when +you depolarize the cell the closed State + + align:start position:0% +you depolarize the cell the closed State + + + align:start position:0% +you depolarize the cell the closed State +suddenly has a much higher energy and as + + align:start position:0% +suddenly has a much higher energy and as + + + align:start position:0% +suddenly has a much higher energy and as +close as close to the open state and so + + align:start position:0% +close as close to the open state and so + + + align:start position:0% +close as close to the open state and so +at some point subunit will jump over to + + align:start position:0% +at some point subunit will jump over to + + + align:start position:0% +at some point subunit will jump over to +the open state right but that takes time + + align:start position:0% +the open state right but that takes time + + + align:start position:0% +the open state right but that takes time +you change the energy levels but it + + align:start position:0% +you change the energy levels but it + + + align:start position:0% +you change the energy levels but it +takes time for the system to jump into + + align:start position:0% +takes time for the system to jump into + + + align:start position:0% +takes time for the system to jump into +the open state why is that because that + + align:start position:0% +the open state why is that because that + + + align:start position:0% +the open state why is that because that +transition is caused by thermal + + align:start position:0% +transition is caused by thermal + + + align:start position:0% +transition is caused by thermal +fluctuations okay + + align:start position:0% +fluctuations okay + + + align:start position:0% +fluctuations okay +so you have to wait for one of those + + align:start position:0% +so you have to wait for one of those + + + align:start position:0% +so you have to wait for one of those +fluctuations to kick you over into the + + align:start position:0% +fluctuations to kick you over into the + + + align:start position:0% +fluctuations to kick you over into the +open state okay so we're going to model + + align:start position:0% +open state okay so we're going to model + + + align:start position:0% +open state okay so we're going to model +those transitions between open and + + align:start position:0% +those transitions between open and + + + align:start position:0% +those transitions between open and +closed States with a simple rate + + align:start position:0% +closed States with a simple rate + + + align:start position:0% +closed States with a simple rate +equation that's voltage dependent we + + align:start position:0% +equation that's voltage dependent we + + + align:start position:0% +equation that's voltage dependent we +have an open state and we imagine that n + + align:start position:0% +have an open state and we imagine that n + + + align:start position:0% +have an open state and we imagine that n +is the probability of being in the open + + align:start position:0% +is the probability of being in the open + + + align:start position:0% +is the probability of being in the open +state and and we can equivalently think + + align:start position:0% +state and and we can equivalently think + + + align:start position:0% +state and and we can equivalently think +of it is if we have a population of + + align:start position:0% +of it is if we have a population of + + + align:start position:0% +of it is if we have a population of +subunits and let's think of it as more + + align:start position:0% +subunits and let's think of it as more + + + align:start position:0% +subunits and let's think of it as more +as the fraction it's it's also + + align:start position:0% +as the fraction it's it's also + + + align:start position:0% +as the fraction it's it's also +equivalent to the just whichever way you + + align:start position:0% +equivalent to the just whichever way you + + + align:start position:0% +equivalent to the just whichever way you +want to think about it either works well + + align:start position:0% +want to think about it either works well + + + align:start position:0% +want to think about it either works well +but you can also think of it as the + + align:start position:0% +but you can also think of it as the + + + align:start position:0% +but you can also think of it as the +probability of being in the open state + + align:start position:0% +probability of being in the open state + + + align:start position:0% +probability of being in the open state +or the number of subunits that are in + + align:start position:0% +or the number of subunits that are in + + + align:start position:0% +or the number of subunits that are in +the open state you know population okay + + align:start position:0% +the open state you know population okay + + + align:start position:0% +the open state you know population okay +you also have a closed state so if n is + + align:start position:0% +you also have a closed state so if n is + + + align:start position:0% +you also have a closed state so if n is +the probability of being in the open + + align:start position:0% +the probability of being in the open + + + align:start position:0% +the probability of being in the open +state of a closed state with probability + + align:start position:0% +state of a closed state with probability + + + align:start position:0% +state of a closed state with probability +1 minus n right if you're in the closed + + align:start position:0% +1 minus n right if you're in the closed + + + align:start position:0% +1 minus n right if you're in the closed +state you have some transition rate + + align:start position:0% +state you have some transition rate + + + align:start position:0% +state you have some transition rate +probability per unit time of going from + + align:start position:0% +probability per unit time of going from + + + align:start position:0% +probability per unit time of going from +the closed state to the open state and + + align:start position:0% +the closed state to the open state and + + + align:start position:0% +the closed state to the open state and +if you're in the open state you have + + align:start position:0% +if you're in the open state you have + + + align:start position:0% +if you're in the open state you have +some probability per unit time beta of + + align:start position:0% +some probability per unit time beta of + + + align:start position:0% +some probability per unit time beta of +going into the closed state okay so + + align:start position:0% +going into the closed state okay so + + + align:start position:0% +going into the closed state okay so +those things have units of per second + + align:start position:0% +those things have units of per second + + + align:start position:0% +those things have units of per second +probability per second yes Rebecca right + + align:start position:0% +probability per second yes Rebecca right + + + align:start position:0% +probability per second yes Rebecca right +yeah just warmth + + align:start position:0% + + + + align:start position:0% + +and these things are voltage dependent + + align:start position:0% +and these things are voltage dependent + + + align:start position:0% +and these things are voltage dependent +remember those depend on the energy + + align:start position:0% +remember those depend on the energy + + + align:start position:0% +remember those depend on the energy +difference between that open and closed + + align:start position:0% +difference between that open and closed + + + align:start position:0% +difference between that open and closed +state okay all right + + align:start position:0% +state okay all right + + + align:start position:0% +state okay all right +let's develop our first-order linear + + align:start position:0% +let's develop our first-order linear + + + align:start position:0% +let's develop our first-order linear +equation it's gonna be very simple we + + align:start position:0% +equation it's gonna be very simple we + + + align:start position:0% +equation it's gonna be very simple we +have a closed state an open state the + + align:start position:0% +have a closed state an open state the + + + align:start position:0% +have a closed state an open state the +change in the number of open states is + + align:start position:0% +change in the number of open states is + + + align:start position:0% +change in the number of open states is +just going to be the number of closed + + align:start position:0% +just going to be the number of closed + + + align:start position:0% +just going to be the number of closed +States the number of closed sub units + + align:start position:0% +States the number of closed sub units + + + align:start position:0% +States the number of closed sub units +that open minus the number of open + + align:start position:0% +that open minus the number of open + + + align:start position:0% +that open minus the number of open +subunits that closed that makes sense + + align:start position:0% +subunits that closed that makes sense + + + align:start position:0% +subunits that closed that makes sense +all right that's simple enough the + + align:start position:0% +all right that's simple enough the + + + align:start position:0% +all right that's simple enough the +change in the number of open sub units + + align:start position:0% +change in the number of open sub units + + + align:start position:0% +change in the number of open sub units +per unit time is going to be the number + + align:start position:0% +per unit time is going to be the number + + + align:start position:0% +per unit time is going to be the number +of closed + + align:start position:0% +of closed + + + align:start position:0% +of closed +sub units that there are times the + + align:start position:0% +sub units that there are times the + + + align:start position:0% +sub units that there are times the +probability that a closed sub unit opens + + align:start position:0% +probability that a closed sub unit opens + + + align:start position:0% +probability that a closed sub unit opens +per unit time that's alpha minus + + align:start position:0% +per unit time that's alpha minus + + + align:start position:0% +per unit time that's alpha minus +remember the number of closed sub units + + align:start position:0% +remember the number of closed sub units + + + align:start position:0% +remember the number of closed sub units +that open is the number of closed sub + + align:start position:0% +that open is the number of closed sub + + + align:start position:0% +that open is the number of closed sub +units times the probability of per unit + + align:start position:0% +units times the probability of per unit + + + align:start position:0% +units times the probability of per unit +time that are closed sub unit opens all + + align:start position:0% +time that are closed sub unit opens all + + + align:start position:0% +time that are closed sub unit opens all +right and the number of open sub units + + align:start position:0% +right and the number of open sub units + + + align:start position:0% +right and the number of open sub units +that closed is just the number of open + + align:start position:0% +that closed is just the number of open + + + align:start position:0% +that closed is just the number of open +sub units times the probability that any + + align:start position:0% +sub units times the probability that any + + + align:start position:0% +sub units times the probability that any +one of them closes per unit time that + + align:start position:0% +one of them closes per unit time that + + + align:start position:0% +one of them closes per unit time that +makes sense okay a lot of words but the + + align:start position:0% +makes sense okay a lot of words but the + + + align:start position:0% +makes sense okay a lot of words but the +equation ends up being very simple the + + align:start position:0% +equation ends up being very simple the + + + align:start position:0% +equation ends up being very simple the +change per unit time of n is just the + + align:start position:0% +change per unit time of n is just the + + + align:start position:0% +change per unit time of n is just the +number of closed sub units 1 times the + + align:start position:0% +number of closed sub units 1 times the + + + align:start position:0% +number of closed sub units 1 times the +probability that those open per unit + + align:start position:0% +probability that those open per unit + + + align:start position:0% +probability that those open per unit +time alpha minus beta times n okay + + align:start position:0% +time alpha minus beta times n okay + + + align:start position:0% +time alpha minus beta times n okay +alpha times 1 minus n minus beta times n + + align:start position:0% +alpha times 1 minus n minus beta times n + + + align:start position:0% +alpha times 1 minus n minus beta times n +okay + + align:start position:0% + + + + align:start position:0% + +any questions about that alpha beta are + + align:start position:0% +any questions about that alpha beta are + + + align:start position:0% +any questions about that alpha beta are +voltage-dependent + + align:start position:0% + + + + align:start position:0% + +okay so I've rewritten that equation and + + align:start position:0% +okay so I've rewritten that equation and + + + align:start position:0% +okay so I've rewritten that equation and +it's the probability that a subunit is + + align:start position:0% +it's the probability that a subunit is + + + align:start position:0% +it's the probability that a subunit is +open okay let's just rewrite this let's + + align:start position:0% +open okay let's just rewrite this let's + + + align:start position:0% +open okay let's just rewrite this let's +expand this alpha minus alpha times M my + + align:start position:0% +expand this alpha minus alpha times M my + + + align:start position:0% +expand this alpha minus alpha times M my +beta times n factor out the end so you + + align:start position:0% +beta times n factor out the end so you + + + align:start position:0% +beta times n factor out the end so you +have DN DT equals alpha minus alpha plus + + align:start position:0% +have DN DT equals alpha minus alpha plus + + + align:start position:0% +have DN DT equals alpha minus alpha plus +beta times n divide both sides by 1 over + + align:start position:0% +beta times n divide both sides by 1 over + + + align:start position:0% +beta times n divide both sides by 1 over +alpha plus beta + + align:start position:0% +alpha plus beta + + + align:start position:0% +alpha plus beta +what's the steady state of this steady + + align:start position:0% +what's the steady state of this steady + + + align:start position:0% +what's the steady state of this steady +state solution of this equation that is + + align:start position:0% +state solution of this equation that is + + + align:start position:0% +state solution of this equation that is +the steady state solution right da if + + align:start position:0% +the steady state solution right da if + + + align:start position:0% +the steady state solution right da if +you set the nd T equal to zero that n is + + align:start position:0% +you set the nd T equal to zero that n is + + + align:start position:0% +you set the nd T equal to zero that n is +equal to that just an infinity and + + align:start position:0% +equal to that just an infinity and + + + align:start position:0% +equal to that just an infinity and +what's that alpha and beta have units of + + align:start position:0% +what's that alpha and beta have units of + + + align:start position:0% +what's that alpha and beta have units of +per unit time so what is 1 what units do + + align:start position:0% +per unit time so what is 1 what units do + + + align:start position:0% +per unit time so what is 1 what units do +1 over alpha plus beta have time so what + + align:start position:0% +1 over alpha plus beta have time so what + + + align:start position:0% +1 over alpha plus beta have time so what +might that be + + align:start position:0% + + + + align:start position:0% + +tau it's a time constant okay so after + + align:start position:0% +tau it's a time constant okay so after + + + align:start position:0% +tau it's a time constant okay so after +all of this what we end up with is an + + align:start position:0% +all of this what we end up with is an + + + align:start position:0% +all of this what we end up with is an +equation that looks exactly like what we + + align:start position:0% +equation that looks exactly like what we + + + align:start position:0% +equation that looks exactly like what we +had for we have a first-order linear + + align:start position:0% +had for we have a first-order linear + + + align:start position:0% +had for we have a first-order linear +differential equation actly the same + + align:start position:0% +differential equation actly the same + + + align:start position:0% +differential equation actly the same +form as the equation we used to + + align:start position:0% +form as the equation we used to + + + align:start position:0% +form as the equation we used to +understand the way the voltage changes + + align:start position:0% +understand the way the voltage changes + + + align:start position:0% +understand the way the voltage changes +in a cell in response to current + + align:start position:0% +in a cell in response to current + + + align:start position:0% +in a cell in response to current +injection okay so if we change and + + align:start position:0% +injection okay so if we change and + + + align:start position:0% +injection okay so if we change and +infinity what is this thing going to do + + align:start position:0% +infinity what is this thing going to do + + + align:start position:0% +infinity what is this thing going to do +it's going to what is n going to do it's + + align:start position:0% +it's going to what is n going to do it's + + + align:start position:0% +it's going to what is n going to do it's +going to relax exponentially okay with a + + align:start position:0% +going to relax exponentially okay with a + + + align:start position:0% +going to relax exponentially okay with a +time constant tau + + align:start position:0% +time constant tau + + + align:start position:0% +time constant tau +and all of these things the Tao is tau + + align:start position:0% +and all of these things the Tao is tau + + + align:start position:0% +and all of these things the Tao is tau +sub n because it's for the end gating + + align:start position:0% +sub n because it's for the end gating + + + align:start position:0% +sub n because it's for the end gating +variable so that's why this has an end + + align:start position:0% +variable so that's why this has an end + + + align:start position:0% +variable so that's why this has an end +here okay + + align:start position:0% +here okay + + + align:start position:0% +here okay +so an infinity and tau are voltage + + align:start position:0% +so an infinity and tau are voltage + + + align:start position:0% +so an infinity and tau are voltage +dependent because they come from alpha + + align:start position:0% +dependent because they come from alpha + + + align:start position:0% +dependent because they come from alpha +and beta which are voltage dependent + + align:start position:0% +and beta which are voltage dependent + + + align:start position:0% +and beta which are voltage dependent +okay but we actually just derived the + + align:start position:0% +okay but we actually just derived the + + + align:start position:0% +okay but we actually just derived the +steady state voltage dependence of the + + align:start position:0% +steady state voltage dependence of the + + + align:start position:0% +steady state voltage dependence of the +potassium conductance right from the + + align:start position:0% +potassium conductance right from the + + + align:start position:0% +potassium conductance right from the +Boltzmann equation what is n infinity + + align:start position:0% +Boltzmann equation what is n infinity + + + align:start position:0% +Boltzmann equation what is n infinity +for very negative voltages do you + + align:start position:0% +for very negative voltages do you + + + align:start position:0% +for very negative voltages do you +remember just approximately big-small + + align:start position:0% +remember just approximately big-small + + + align:start position:0% +remember just approximately big-small +1/2 what is the steady state what's the + + align:start position:0% +1/2 what is the steady state what's the + + + align:start position:0% +1/2 what is the steady state what's the +probability that a potassium channel is + + align:start position:0% +probability that a potassium channel is + + + align:start position:0% +probability that a potassium channel is +open that a subunit is open at very + + align:start position:0% +open that a subunit is open at very + + + align:start position:0% +open that a subunit is open at very +negative voltages do you remember zero + + align:start position:0% +negative voltages do you remember zero + + + align:start position:0% +negative voltages do you remember zero +it's off for look big voltage and + + align:start position:0% +it's off for look big voltage and + + + align:start position:0% +it's off for look big voltage and +infinity has to be if we think of it as + + align:start position:0% +infinity has to be if we think of it as + + + align:start position:0% +infinity has to be if we think of it as +a probability it's close to 1 so n + + align:start position:0% +a probability it's close to 1 so n + + + align:start position:0% +a probability it's close to 1 so n +infinity goes from zero at negative + + align:start position:0% +infinity goes from zero at negative + + + align:start position:0% +infinity goes from zero at negative +voltages sigmoid activation up to one at + + align:start position:0% +voltages sigmoid activation up to one at + + + align:start position:0% +voltages sigmoid activation up to one at +high voltages ok okay so now let's let's + + align:start position:0% +high voltages ok okay so now let's let's + + + align:start position:0% +high voltages ok okay so now let's let's +look at how n changes as a function of + + align:start position:0% +look at how n changes as a function of + + + align:start position:0% +look at how n changes as a function of +time so here's our our potential we're + + align:start position:0% +time so here's our our potential we're + + + align:start position:0% +time so here's our our potential we're +gonna do a voltage clamp experiment + + align:start position:0% +gonna do a voltage clamp experiment + + + align:start position:0% +gonna do a voltage clamp experiment +we're going to start at minus eighty + + align:start position:0% +we're going to start at minus eighty + + + align:start position:0% +we're going to start at minus eighty +millivolts and step up to zero okay so + + align:start position:0% +millivolts and step up to zero okay so + + + align:start position:0% +millivolts and step up to zero okay so +what is an infinity going to do an + + align:start position:0% +what is an infinity going to do an + + + align:start position:0% +what is an infinity going to do an +infinity is just a function of voltage + + align:start position:0% +infinity is just a function of voltage + + + align:start position:0% +infinity is just a function of voltage +right it's like those energy levels they + + align:start position:0% +right it's like those energy levels they + + + align:start position:0% +right it's like those energy levels they +change immediately so what is an + + align:start position:0% +change immediately so what is an + + + align:start position:0% +change immediately so what is an +infinity going to do good it's gonna + + align:start position:0% +infinity going to do good it's gonna + + + align:start position:0% +infinity going to do good it's gonna +start at close to zero jump up to one + + align:start position:0% +start at close to zero jump up to one + + + align:start position:0% +start at close to zero jump up to one +and then jump back to close to zero + + align:start position:0% +and then jump back to close to zero + + + align:start position:0% +and then jump back to close to zero +immediately following the voltage okay + + align:start position:0% +immediately following the voltage okay + + + align:start position:0% +immediately following the voltage okay +but what is n going to do now let's plot + + align:start position:0% +but what is n going to do now let's plot + + + align:start position:0% +but what is n going to do now let's plot +n + + align:start position:0% +n + + + align:start position:0% +n +and it's going to start at zero when you + + align:start position:0% +and it's going to start at zero when you + + + align:start position:0% +and it's going to start at zero when you +jump the when you step the voltage up + + align:start position:0% +jump the when you step the voltage up + + + align:start position:0% +jump the when you step the voltage up +and infinity will jump up and n will + + align:start position:0% +and infinity will jump up and n will + + + align:start position:0% +and infinity will jump up and n will +relax exponentially to a high end + + align:start position:0% +relax exponentially to a high end + + + align:start position:0% +relax exponentially to a high end +infinity close to one right and then + + align:start position:0% +infinity close to one right and then + + + align:start position:0% +infinity close to one right and then +when we turn back and infinity jumps + + align:start position:0% +when we turn back and infinity jumps + + + align:start position:0% +when we turn back and infinity jumps +back down to zero and n relaxes + + align:start position:0% +back down to zero and n relaxes + + + align:start position:0% +back down to zero and n relaxes +exponentially back yes yes but but for a + + align:start position:0% +exponentially back yes yes but but for a + + + align:start position:0% +exponentially back yes yes but but for a +voltage around zero and infinity is + + align:start position:0% +voltage around zero and infinity is + + + align:start position:0% +voltage around zero and infinity is +going to be close to one okay any any + + align:start position:0% +going to be close to one okay any any + + + align:start position:0% +going to be close to one okay any any +questions + + align:start position:0% + + + + align:start position:0% + +that is called activation that's the + + align:start position:0% +that is called activation that's the + + + align:start position:0% +that is called activation that's the +that's the activation now this this + + align:start position:0% +that's the activation now this this + + + align:start position:0% +that's the activation now this this +looks a little funny right this this + + align:start position:0% +looks a little funny right this this + + + align:start position:0% +looks a little funny right this this +thing is turning on immediately it + + align:start position:0% +thing is turning on immediately it + + + align:start position:0% +thing is turning on immediately it +doesn't have that nice sigmoid alape + + align:start position:0% +doesn't have that nice sigmoid alape + + + align:start position:0% +doesn't have that nice sigmoid alape +that the potassium current had right or + + align:start position:0% +that the potassium current had right or + + + align:start position:0% +that the potassium current had right or +the protectants why is that what are we + + align:start position:0% +the protectants why is that what are we + + + align:start position:0% +the protectants why is that what are we +looking at here we're plotting n what is + + align:start position:0% +looking at here we're plotting n what is + + + align:start position:0% +looking at here we're plotting n what is +the potassium conductance or the current + + align:start position:0% +the potassium conductance or the current + + + align:start position:0% +the potassium conductance or the current +how does that relate to n n to the + + align:start position:0% +how does that relate to n n to the + + + align:start position:0% +how does that relate to n n to the +fourth so what do we do to plot the + + align:start position:0% +fourth so what do we do to plot the + + + align:start position:0% +fourth so what do we do to plot the +potassium current or the potassium + + align:start position:0% +potassium current or the potassium + + + align:start position:0% +potassium current or the potassium +conductance we just take this right so + + align:start position:0% +conductance we just take this right so + + + align:start position:0% +conductance we just take this right so +what does that look like this process of + + align:start position:0% +what does that look like this process of + + + align:start position:0% +what does that look like this process of +turning off the gating variable getting + + align:start position:0% +turning off the gating variable getting + + + align:start position:0% +turning off the gating variable getting +bigger is called activation the gating + + align:start position:0% +bigger is called activation the gating + + + align:start position:0% +bigger is called activation the gating +variable getting smaller and getting + + align:start position:0% +variable getting smaller and getting + + + align:start position:0% +variable getting smaller and getting +smaller is called dis activation okay so + + align:start position:0% +smaller is called dis activation okay so + + + align:start position:0% +smaller is called dis activation okay so +now let's plot this to the fourth so + + align:start position:0% +now let's plot this to the fourth so + + + align:start position:0% +now let's plot this to the fourth so +this conductance turns on gradually but + + align:start position:0% +this conductance turns on gradually but + + + align:start position:0% +this conductance turns on gradually but +the conductance is proportional to n to + + align:start position:0% +the conductance is proportional to n to + + + align:start position:0% +the conductance is proportional to n to +the fourth so let's plot that so if we + + align:start position:0% +the fourth so let's plot that so if we + + + align:start position:0% +the fourth so let's plot that so if we +plot N to the fourth you can see that + + align:start position:0% +plot N to the fourth you can see that + + + align:start position:0% +plot N to the fourth you can see that +that that function now turns on smoothly + + align:start position:0% +that that function now turns on smoothly + + + align:start position:0% +that that function now turns on smoothly +in time this is time now right so that + + align:start position:0% +in time this is time now right so that + + + align:start position:0% +in time this is time now right so that +gating variable ends relaxes + + align:start position:0% +gating variable ends relaxes + + + align:start position:0% +gating variable ends relaxes +exponentially but the conductance goes + + align:start position:0% +exponentially but the conductance goes + + + align:start position:0% +exponentially but the conductance goes +as the gating variable to the fourth and + + align:start position:0% +as the gating variable to the fourth and + + + align:start position:0% +as the gating variable to the fourth and +so it has this nice graceful turn on + + align:start position:0% +so it has this nice graceful turn on + + + align:start position:0% +so it has this nice graceful turn on +right because it's the gating + + align:start position:0% +right because it's the gating + + + align:start position:0% +right because it's the gating +exponential to the fourth looks exactly + + align:start position:0% +exponential to the fourth looks exactly + + + align:start position:0% +exponential to the fourth looks exactly +like this okay in fact that's how + + align:start position:0% +like this okay in fact that's how + + + align:start position:0% +like this okay in fact that's how +Hodgkin and Huxley figured out that its + + align:start position:0% +Hodgkin and Huxley figured out that its + + + align:start position:0% +Hodgkin and Huxley figured out that its +end to the four because they knew that + + align:start position:0% +end to the four because they knew that + + + align:start position:0% +end to the four because they knew that +they if they assume that it's a + + align:start position:0% +they if they assume that it's a + + + align:start position:0% +they if they assume that it's a +exponentially decaying gating variable + + align:start position:0% +exponentially decaying gating variable + + + align:start position:0% +exponentially decaying gating variable +that the only way they could fit the + + align:start position:0% +that the only way they could fit the + + + align:start position:0% +that the only way they could fit the +turn on of the conductance was by + + align:start position:0% +turn on of the conductance was by + + + align:start position:0% +turn on of the conductance was by +raising it to the fourth power if they + + align:start position:0% +raising it to the fourth power if they + + + align:start position:0% +raising it to the fourth power if they +raised it to the second power it was + + align:start position:0% +raised it to the second power it was + + + align:start position:0% +raised it to the second power it was +still too sudden if they raised it to + + align:start position:0% +still too sudden if they raised it to + + + align:start position:0% +still too sudden if they raised it to +the third power it was still not quite + + align:start position:0% +the third power it was still not quite + + + align:start position:0% +the third power it was still not quite +right but if they raised it to the fifth + + align:start position:0% +right but if they raised it to the fifth + + + align:start position:0% +right but if they raised it to the fifth +power + + align:start position:0% +power + + + align:start position:0% +power +oops it's too delayed if they were + + align:start position:0% +oops it's too delayed if they were + + + align:start position:0% +oops it's too delayed if they were +horsepower it exactly fits the shape of + + align:start position:0% +horsepower it exactly fits the shape of + + + align:start position:0% +horsepower it exactly fits the shape of +the conductance turning on and so they + + align:start position:0% +the conductance turning on and so they + + + align:start position:0% +the conductance turning on and so they +inferred they didn't know about subunits + + align:start position:0% +inferred they didn't know about subunits + + + align:start position:0% +inferred they didn't know about subunits +they just had a piece of axon you know a + + align:start position:0% +they just had a piece of axon you know a + + + align:start position:0% +they just had a piece of axon you know a +piece of squid line and a table in front + + align:start position:0% +piece of squid line and a table in front + + + align:start position:0% +piece of squid line and a table in front +of them and they figure out that there + + align:start position:0% +of them and they figure out that there + + + align:start position:0% +of them and they figure out that there +were four independent processes that + + align:start position:0% +were four independent processes that + + + align:start position:0% +were four independent processes that +turn on the potassium conductance pretty + + align:start position:0% +turn on the potassium conductance pretty + + + align:start position:0% +turn on the potassium conductance pretty +cool right that's what you get by doing + + align:start position:0% +cool right that's what you get by doing + + + align:start position:0% +cool right that's what you get by doing +things quantitatively so they could the + + align:start position:0% +things quantitatively so they could the + + + align:start position:0% +things quantitatively so they could the +shape of that potassium conductance + + align:start position:0% +shape of that potassium conductance + + + align:start position:0% +shape of that potassium conductance +turning on by this exponential gating + + align:start position:0% +turning on by this exponential gating + + + align:start position:0% +turning on by this exponential gating +variable raised to the fourth power and + + align:start position:0% + + + + align:start position:0% + +from that they were able to infer that + + align:start position:0% +from that they were able to infer that + + + align:start position:0% +from that they were able to infer that +it's for independent first-order + + align:start position:0% +it's for independent first-order + + + align:start position:0% +it's for independent first-order +processes that combine to produce that + + align:start position:0% +processes that combine to produce that + + + align:start position:0% +processes that combine to produce that +activation okay the offset also fits if + + align:start position:0% +activation okay the offset also fits if + + + align:start position:0% +activation okay the offset also fits if +you raise it to the fourth power they + + align:start position:0% +you raise it to the fourth power they + + + align:start position:0% +you raise it to the fourth power they +were able to measure the size of the + + align:start position:0% +were able to measure the size of the + + + align:start position:0% +were able to measure the size of the +potassium conductance to measure an + + align:start position:0% +potassium conductance to measure an + + + align:start position:0% +potassium conductance to measure an +infinity directly so we derived it using + + align:start position:0% +infinity directly so we derived it using + + + align:start position:0% +infinity directly so we derived it using +the Boltzmann equation but they measured + + align:start position:0% +the Boltzmann equation but they measured + + + align:start position:0% +the Boltzmann equation but they measured +it directly just by the size of the + + align:start position:0% +it directly just by the size of the + + + align:start position:0% +it directly just by the size of the +conductance and you can also measure the + + align:start position:0% +conductance and you can also measure the + + + align:start position:0% +conductance and you can also measure the +time course you don't need to worry + + align:start position:0% +time course you don't need to worry + + + align:start position:0% +time course you don't need to worry +about this I'm not expecting you should + + align:start position:0% +about this I'm not expecting you should + + + align:start position:0% +about this I'm not expecting you should +know this I'm just showing you that just + + align:start position:0% +know this I'm just showing you that just + + + align:start position:0% +know this I'm just showing you that just +for fun you don't need to know that okay + + align:start position:0% + + + + align:start position:0% + +and you can extract these towels just by + + align:start position:0% +and you can extract these towels just by + + + align:start position:0% +and you can extract these towels just by +measuring this exponential decay at + + align:start position:0% +measuring this exponential decay at + + + align:start position:0% +measuring this exponential decay at +different voltages or measuring these + + align:start position:0% +different voltages or measuring these + + + align:start position:0% +different voltages or measuring these +the inferred first order process you can + + align:start position:0% +the inferred first order process you can + + + align:start position:0% +the inferred first order process you can +infer the time constant of the first + + align:start position:0% +infer the time constant of the first + + + align:start position:0% +infer the time constant of the first +order process so on the onset and the + + align:start position:0% +order process so on the onset and the + + + align:start position:0% +order process so on the onset and the +offset to extract these towels as a + + align:start position:0% +offset to extract these towels as a + + + align:start position:0% +offset to extract these towels as a +function of volt this is tau as a + + align:start position:0% +function of volt this is tau as a + + + align:start position:0% +function of volt this is tau as a +function of voltage okay you can also + + align:start position:0% +function of voltage okay you can also + + + align:start position:0% +function of voltage okay you can also +from these two quantities you can + + align:start position:0% +from these two quantities you can + + + align:start position:0% +from these two quantities you can +actually extract alpha and beta + + align:start position:0% +actually extract alpha and beta + + + align:start position:0% +actually extract alpha and beta +and so you can write down a simple out + + align:start position:0% +and so you can write down a simple out + + + align:start position:0% +and so you can write down a simple out +algebraic expression for alpha and beta + + align:start position:0% +algebraic expression for alpha and beta + + + align:start position:0% +algebraic expression for alpha and beta +and that's the way they actually wrote + + align:start position:0% +and that's the way they actually wrote + + + align:start position:0% +and that's the way they actually wrote +those things down they wrote them down + + align:start position:0% +those things down they wrote them down + + + align:start position:0% +those things down they wrote them down +as alpha and beta rather than an + + align:start position:0% +as alpha and beta rather than an + + + align:start position:0% +as alpha and beta rather than an +infinity Intel okay so you can actually + + align:start position:0% +infinity Intel okay so you can actually + + + align:start position:0% +infinity Intel okay so you can actually +those are simple expressions for alpha + + align:start position:0% +those are simple expressions for alpha + + + align:start position:0% +those are simple expressions for alpha +and beta in units of per millisecond as + + align:start position:0% +and beta in units of per millisecond as + + + align:start position:0% +and beta in units of per millisecond as +a function of voltage in units of + + align:start position:0% +a function of voltage in units of + + + align:start position:0% +a function of voltage in units of +millivolts okay I think I think yeah + + align:start position:0% +millivolts okay I think I think yeah + + + align:start position:0% +millivolts okay I think I think yeah +it's millivolts yeah there it is right + + align:start position:0% +it's millivolts yeah there it is right + + + align:start position:0% +it's millivolts yeah there it is right +there okay so you can actually just take + + align:start position:0% +there okay so you can actually just take + + + align:start position:0% +there okay so you can actually just take +those parameters right and calculate n + + align:start position:0% +those parameters right and calculate n + + + align:start position:0% +those parameters right and calculate n +infinity and tau N and calculate the + + align:start position:0% +infinity and tau N and calculate the + + + align:start position:0% +infinity and tau N and calculate the +gating variable from that using that + + align:start position:0% +gating variable from that using that + + + align:start position:0% +gating variable from that using that +differential equation okay so we have + + align:start position:0% +differential equation okay so we have + + + align:start position:0% +differential equation okay so we have +these nice expressions for what the + + align:start position:0% +these nice expressions for what the + + + align:start position:0% +these nice expressions for what the +steady state and infinity and tau NR + + align:start position:0% + + + + align:start position:0% + +okay now why did we yes yes they're per + + align:start position:0% +okay now why did we yes yes they're per + + + align:start position:0% +okay now why did we yes yes they're per +unit time yeah so they have units of per + + align:start position:0% +unit time yeah so they have units of per + + + align:start position:0% +unit time yeah so they have units of per +millisecond okay so now let's come back + + align:start position:0% +millisecond okay so now let's come back + + + align:start position:0% +millisecond okay so now let's come back +to our picture we have an infinity and + + align:start position:0% +to our picture we have an infinity and + + + align:start position:0% +to our picture we have an infinity and +tau n as a function of voltage now we + + align:start position:0% +tau n as a function of voltage now we + + + align:start position:0% +tau n as a function of voltage now we +just can plug those into this + + align:start position:0% +just can plug those into this + + + align:start position:0% +just can plug those into this +differential equation and solve for n + + align:start position:0% +differential equation and solve for n + + + align:start position:0% +differential equation and solve for n +well we already know what that does it + + align:start position:0% +well we already know what that does it + + + align:start position:0% +well we already know what that does it +just N relaxes exponentially toward an + + align:start position:0% +just N relaxes exponentially toward an + + + align:start position:0% +just N relaxes exponentially toward an +infinity with a time constant tau but + + align:start position:0% +infinity with a time constant tau but + + + align:start position:0% +infinity with a time constant tau but +you can integrate that numerically you + + align:start position:0% +you can integrate that numerically you + + + align:start position:0% +you can integrate that numerically you +get the potassium conductance as n to + + align:start position:0% +get the potassium conductance as n to + + + align:start position:0% +get the potassium conductance as n to +the 4G times n to the 4 you get the + + align:start position:0% +the 4G times n to the 4 you get the + + + align:start position:0% +the 4G times n to the 4 you get the +potassium current as GN to the 4 times + + align:start position:0% +potassium current as GN to the 4 times + + + align:start position:0% +potassium current as GN to the 4 times +the driving potential or V - EK okay and + + align:start position:0% +the driving potential or V - EK okay and + + + align:start position:0% +the driving potential or V - EK okay and +now let's come back to our algorithm for + + align:start position:0% +now let's come back to our algorithm for + + + align:start position:0% +now let's come back to our algorithm for +making an action potential so we have + + align:start position:0% +making an action potential so we have + + + align:start position:0% +making an action potential so we have +the parts related to the potassium + + align:start position:0% +the parts related to the potassium + + + align:start position:0% +the parts related to the potassium +current we still have to add the parts + + align:start position:0% +current we still have to add the parts + + + align:start position:0% +current we still have to add the parts +related to sodium but it's going to look + + align:start position:0% +related to sodium but it's going to look + + + align:start position:0% +related to sodium but it's going to look +very similar so here's the idea we start + + align:start position:0% +very similar so here's the idea we start + + + align:start position:0% +very similar so here's the idea we start +with the membrane potential at time step + + align:start position:0% +with the membrane potential at time step + + + align:start position:0% +with the membrane potential at time step +T we compute n infinity and tau n we + + align:start position:0% +T we compute n infinity and tau n we + + + align:start position:0% +T we compute n infinity and tau n we +integrate DN DT + + align:start position:0% +integrate DN DT + + + align:start position:0% +integrate DN DT +one time step to get the next n plug n + + align:start position:0% +one time step to get the next n plug n + + + align:start position:0% +one time step to get the next n plug n +into our equation to get the potassium + + align:start position:0% +into our equation to get the potassium + + + align:start position:0% +into our equation to get the potassium +current we then add that to all the + + align:start position:0% +current we then add that to all the + + + align:start position:0% +current we then add that to all the +other currents to get the total membrane + + align:start position:0% +other currents to get the total membrane + + + align:start position:0% +other currents to get the total membrane +current we compute the infinity of the + + align:start position:0% +current we compute the infinity of the + + + align:start position:0% +current we compute the infinity of the +cell we integrate dv/dt one time step to + + align:start position:0% +cell we integrate dv/dt one time step to + + + align:start position:0% +cell we integrate dv/dt one time step to +get the next voltage and you plug that + + align:start position:0% +get the next voltage and you plug that + + + align:start position:0% +get the next voltage and you plug that +in and calculate the next and infinity + + align:start position:0% +in and calculate the next and infinity + + + align:start position:0% +in and calculate the next and infinity +all right + + align:start position:0% +all right + + + align:start position:0% +all right +so we still have to add the sodium parts + + align:start position:0% +so we still have to add the sodium parts + + + align:start position:0% +so we still have to add the sodium parts +but you can see we've gone through all + + align:start position:0% +but you can see we've gone through all + + + align:start position:0% +but you can see we've gone through all +of these steps for the potassium okay + + align:start position:0% +of these steps for the potassium okay + + + align:start position:0% +of these steps for the potassium okay +and so work just this shy of having a + + align:start position:0% +and so work just this shy of having a + + + align:start position:0% +and so work just this shy of having a +full-blown algorithm for an action + + align:start position:0% +full-blown algorithm for an action + + + align:start position:0% +full-blown algorithm for an action +potential in a neuron okay and not only + + align:start position:0% +potential in a neuron okay and not only + + + align:start position:0% +potential in a neuron okay and not only +do you understand all the little steps + + align:start position:0% +do you understand all the little steps + + + align:start position:0% +do you understand all the little steps +but you understand that fundamental + + align:start position:0% +but you understand that fundamental + + + align:start position:0% +but you understand that fundamental +biophysics that leads to that voltage + + align:start position:0% +biophysics that leads to that voltage + + + align:start position:0% +biophysics that leads to that voltage +and time dependence okay all right so + + align:start position:0% +and time dependence okay all right so + + + align:start position:0% +and time dependence okay all right so +again what I'd like you to be able to do + + align:start position:0% +again what I'd like you to be able to do + + + align:start position:0% +again what I'd like you to be able to do +is to draw that circuit the + + align:start position:0% +is to draw that circuit the + + + align:start position:0% +is to draw that circuit the +hodgkin-huxley model I'd like you to be + + align:start position:0% +hodgkin-huxley model I'd like you to be + + + align:start position:0% +hodgkin-huxley model I'd like you to be +able to explain at a basic level what a + + align:start position:0% +able to explain at a basic level what a + + + align:start position:0% +able to explain at a basic level what a +voltage clamp is and how it works + + align:start position:0% +voltage clamp is and how it works + + + align:start position:0% +voltage clamp is and how it works +we'd like you to be able to plot the + + align:start position:0% +we'd like you to be able to plot the + + + align:start position:0% +we'd like you to be able to plot the +voltage and time dependence of the + + align:start position:0% +voltage and time dependence of the + + + align:start position:0% +voltage and time dependence of the +potassium current remember this sigmoid + + align:start position:0% +potassium current remember this sigmoid + + + align:start position:0% +potassium current remember this sigmoid +'el activation of the potassium current + + align:start position:0% +'el activation of the potassium current + + + align:start position:0% +'el activation of the potassium current +and the conductance voltage and time + + align:start position:0% +and the conductance voltage and time + + + align:start position:0% +and the conductance voltage and time +dependence and be able to explain the + + align:start position:0% +dependence and be able to explain the + + + align:start position:0% +dependence and be able to explain the +time and voltage depends to the + + align:start position:0% +time and voltage depends to the + + + align:start position:0% +time and voltage depends to the +potassium conductance in terms of the + + align:start position:0% +potassium conductance in terms of the + + + align:start position:0% +potassium conductance in terms of the +hodgkin-huxley gating variables okay + + align:start position:0% + + + + align:start position:0% + +you \ No newline at end of file diff --git a/8MLEYc3PLUc.txt b/8MLEYc3PLUc.txt new file mode 100644 index 0000000000000000000000000000000000000000..3762f8d2bc740aafd7dfb6b5c5134b89b1c7c2fc --- /dev/null +++ b/8MLEYc3PLUc.txt @@ -0,0 +1,1051 @@ +align:start position:0% + +we're speaking today with Heidi + + align:start position:0% +we're speaking today with Heidi + + + align:start position:0% +we're speaking today with Heidi +scherholz the chief Economist at the US + + align:start position:0% +scherholz the chief Economist at the US + + + align:start position:0% +scherholz the chief Economist at the US +Department of Labor Heidi follows the + + align:start position:0% +Department of Labor Heidi follows the + + + align:start position:0% +Department of Labor Heidi follows the +job Trends and occupational + + align:start position:0% +job Trends and occupational + + + align:start position:0% +job Trends and occupational +opportunities uh around the country and + + align:start position:0% +opportunities uh around the country and + + + align:start position:0% +opportunities uh around the country and +so this is a good opportunity to discuss + + align:start position:0% +so this is a good opportunity to discuss + + + align:start position:0% +so this is a good opportunity to discuss +where some of the good jobs are so Heidi + + align:start position:0% +where some of the good jobs are so Heidi + + + align:start position:0% +where some of the good jobs are so Heidi +thank you for joining us today it's my + + align:start position:0% +thank you for joining us today it's my + + + align:start position:0% +thank you for joining us today it's my +pleasure I wonder if you could start by + + align:start position:0% +pleasure I wonder if you could start by + + + align:start position:0% +pleasure I wonder if you could start by +telling us what do you see as some of + + align:start position:0% +telling us what do you see as some of + + + align:start position:0% +telling us what do you see as some of +the good job opportunities for young + + align:start position:0% +the good job opportunities for young + + + align:start position:0% +the good job opportunities for young +people entering the labor force today I + + align:start position:0% +people entering the labor force today I + + + align:start position:0% +people entering the labor force today I +think it's important to know that there + + align:start position:0% +think it's important to know that there + + + align:start position:0% +think it's important to know that there +are a lot of good jobs being created + + align:start position:0% +are a lot of good jobs being created + + + align:start position:0% +are a lot of good jobs being created +there are a lot of good opportunities + + align:start position:0% +there are a lot of good opportunities + + + align:start position:0% +there are a lot of good opportunities +and if you look our Bureau of Labor + + align:start position:0% +and if you look our Bureau of Labor + + + align:start position:0% +and if you look our Bureau of Labor +Statistics does these employment + + align:start position:0% +Statistics does these employment + + + align:start position:0% +Statistics does these employment +projections where you can look and see + + align:start position:0% +projections where you can look and see + + + align:start position:0% +projections where you can look and see +what kind of jobs are growing strongly + + align:start position:0% +what kind of jobs are growing strongly + + + align:start position:0% +what kind of jobs are growing strongly +for the next 10 years what kind of wages + + align:start position:0% +for the next 10 years what kind of wages + + + align:start position:0% +for the next 10 years what kind of wages +will those jobs have and there's some + + align:start position:0% +will those jobs have and there's some + + + align:start position:0% +will those jobs have and there's some +trends that come out of that that you + + align:start position:0% +trends that come out of that that you + + + align:start position:0% +trends that come out of that that you +can see so some of the fastest growing + + align:start position:0% +can see so some of the fastest growing + + + align:start position:0% +can see so some of the fastest growing +jobs our jobs in the health sector + + align:start position:0% +jobs our jobs in the health sector + + + align:start position:0% +jobs our jobs in the health sector +particularly nurses really strong wages + + align:start position:0% +particularly nurses really strong wages + + + align:start position:0% +particularly nurses really strong wages +and really strong strong job growth we + + align:start position:0% +and really strong strong job growth we + + + align:start position:0% +and really strong strong job growth we +also see good job growth in the tech + + align:start position:0% +also see good job growth in the tech + + + align:start position:0% +also see good job growth in the tech +sector so software engineering software + + align:start position:0% +sector so software engineering software + + + align:start position:0% +sector so software engineering software +development those kinds of jobs are + + align:start position:0% +development those kinds of jobs are + + + align:start position:0% +development those kinds of jobs are +growing quickly you also see projected + + align:start position:0% +growing quickly you also see projected + + + align:start position:0% +growing quickly you also see projected +growth in some jobs in professional and + + align:start position:0% +growth in some jobs in professional and + + + align:start position:0% +growth in some jobs in professional and +business services like accountant jobs + + align:start position:0% +business services like accountant jobs + + + align:start position:0% +business services like accountant jobs +and auditing jobs sort of those old + + align:start position:0% +and auditing jobs sort of those old + + + align:start position:0% +and auditing jobs sort of those old +standbys we're going to always need them + + align:start position:0% +standbys we're going to always need them + + + align:start position:0% +standbys we're going to always need them +and they're really decent paying jobs so + + align:start position:0% +and they're really decent paying jobs so + + + align:start position:0% +and they're really decent paying jobs so +that's at the high end of the labor + + align:start position:0% +that's at the high end of the labor + + + align:start position:0% +that's at the high end of the labor +force how about at the middle tier of + + align:start position:0% +force how about at the middle tier of + + + align:start position:0% +force how about at the middle tier of +the labor force what's happening there + + align:start position:0% +the labor force what's happening there + + + align:start position:0% +the labor force what's happening there +one of the phenomenons that we're seeing + + align:start position:0% +one of the phenomenons that we're seeing + + + align:start position:0% +one of the phenomenons that we're seeing +there is there's this big group of + + align:start position:0% +there is there's this big group of + + + align:start position:0% +there is there's this big group of +people who are hitting retirement age + + align:start position:0% +people who are hitting retirement age + + + align:start position:0% +people who are hitting retirement age +the Baby Boomers and as that continues + + align:start position:0% +the Baby Boomers and as that continues + + + align:start position:0% +the Baby Boomers and as that continues +to happen there's going to be a lot of + + align:start position:0% +to happen there's going to be a lot of + + + align:start position:0% +to happen there's going to be a lot of +job turnover in some of these really + + align:start position:0% +job turnover in some of these really + + + align:start position:0% +job turnover in some of these really +good middleclass jobs like carpenter + + align:start position:0% +good middleclass jobs like carpenter + + + align:start position:0% +good middleclass jobs like carpenter +jobs electrician jobs um utility workers + + align:start position:0% +jobs electrician jobs um utility workers + + + align:start position:0% +jobs electrician jobs um utility workers +uh welders those kinds of jobs that + + align:start position:0% +uh welders those kinds of jobs that + + + align:start position:0% +uh welders those kinds of jobs that +historically people got a lot of + + align:start position:0% +historically people got a lot of + + + align:start position:0% +historically people got a lot of +training in those kind of jobs through + + align:start position:0% +training in those kind of jobs through + + + align:start position:0% +training in those kind of jobs through +their unions in apprenticeship programs + + align:start position:0% +their unions in apprenticeship programs + + + align:start position:0% +their unions in apprenticeship programs +as we have the this group of people that + + align:start position:0% +as we have the this group of people that + + + align:start position:0% +as we have the this group of people that +was trained in that way hitting + + align:start position:0% +was trained in that way hitting + + + align:start position:0% +was trained in that way hitting +retirement age we have to really figure + + align:start position:0% +retirement age we have to really figure + + + align:start position:0% +retirement age we have to really figure +out how we're going to refill those jobs + + align:start position:0% +out how we're going to refill those jobs + + + align:start position:0% +out how we're going to refill those jobs +one of the things the Department of + + align:start position:0% +one of the things the Department of + + + align:start position:0% +one of the things the Department of +Labor is doing is really doing + + align:start position:0% +Labor is doing is really doing + + + align:start position:0% +Labor is doing is really doing +everything we can to support + + align:start position:0% +everything we can to support + + + align:start position:0% +everything we can to support +apprenticeship programs they can help + + align:start position:0% +apprenticeship programs they can help + + + align:start position:0% +apprenticeship programs they can help +train up people to get into those jobs + + align:start position:0% +train up people to get into those jobs + + + align:start position:0% +train up people to get into those jobs +because those are really good middle + + align:start position:0% +because those are really good middle + + + align:start position:0% +because those are really good middle +class jobs that are going to be very in + + align:start position:0% +class jobs that are going to be very in + + + align:start position:0% +class jobs that are going to be very in +demand going forward well that's great + + align:start position:0% +demand going forward well that's great + + + align:start position:0% +demand going forward well that's great +because apprenticeships have such a + + align:start position:0% +because apprenticeships have such a + + + align:start position:0% +because apprenticeships have such a +positive records so rebuilding those is + + align:start position:0% +positive records so rebuilding those is + + + align:start position:0% +positive records so rebuilding those is +so critical to our economy and the + + align:start position:0% +so critical to our economy and the + + + align:start position:0% +so critical to our economy and the +future Workforce research shows + + align:start position:0% +future Workforce research shows + + + align:start position:0% +future Workforce research shows +apprenticeship has the highest rate of + + align:start position:0% +apprenticeship has the highest rate of + + + align:start position:0% +apprenticeship has the highest rate of +return as far as investment in workers + + align:start position:0% +return as far as investment in workers + + + align:start position:0% +return as far as investment in workers +what pays off for the economy for their + + align:start position:0% +what pays off for the economy for their + + + align:start position:0% +what pays off for the economy for their +future earnings so it's a really good um + + align:start position:0% +future earnings so it's a really good um + + + align:start position:0% +future earnings so it's a really good um +it's a really good route for our country + + align:start position:0% +it's a really good route for our country + + + align:start position:0% +it's a really good route for our country +to invest in and for people to take + + align:start position:0% +to invest in and for people to take + + + align:start position:0% +to invest in and for people to take +advantage of as they're thinking about + + align:start position:0% +advantage of as they're thinking about + + + align:start position:0% +advantage of as they're thinking about +what their careers are going to look + + align:start position:0% +what their careers are going to look + + + align:start position:0% +what their careers are going to look +like going forward and what about at the + + align:start position:0% +like going forward and what about at the + + + align:start position:0% +like going forward and what about at the +lower end of the occupational + + align:start position:0% +lower end of the occupational + + + align:start position:0% +lower end of the occupational +distribution the projections show that + + align:start position:0% +distribution the projections show that + + + align:start position:0% +distribution the projections show that +we are expeced to add a lot of jobs that + + align:start position:0% +we are expeced to add a lot of jobs that + + + align:start position:0% +we are expeced to add a lot of jobs that +at this point are low-wage jobs home + + align:start position:0% +at this point are low-wage jobs home + + + align:start position:0% +at this point are low-wage jobs home +health aids food prep workers in + + align:start position:0% +health aids food prep workers in + + + align:start position:0% +health aids food prep workers in +restaurants and bars child care workers + + align:start position:0% +restaurants and bars child care workers + + + align:start position:0% +restaurants and bars child care workers +janitors maids and housekeeping cleaners + + align:start position:0% +janitors maids and housekeeping cleaners + + + align:start position:0% +janitors maids and housekeeping cleaners +so some of these lower-end jobs are + + align:start position:0% +so some of these lower-end jobs are + + + align:start position:0% +so some of these lower-end jobs are +projected to see strong growth going + + align:start position:0% +projected to see strong growth going + + + align:start position:0% +projected to see strong growth going +forward so what I think that's a really + + align:start position:0% +forward so what I think that's a really + + + align:start position:0% +forward so what I think that's a really +important segment of the labor market to + + align:start position:0% +important segment of the labor market to + + + align:start position:0% +important segment of the labor market to +think about and that's where policy can + + align:start position:0% +think about and that's where policy can + + + align:start position:0% +think about and that's where policy can +come in to help make sure that those are + + align:start position:0% +come in to help make sure that those are + + + align:start position:0% +come in to help make sure that those are +better jobs so things like making sure + + align:start position:0% +better jobs so things like making sure + + + align:start position:0% +better jobs so things like making sure +um we have a decent minimum wage + + align:start position:0% +um we have a decent minimum wage + + + align:start position:0% +um we have a decent minimum wage +increasing the minimum wage making sure + + align:start position:0% +increasing the minimum wage making sure + + + align:start position:0% +increasing the minimum wage making sure +people have overtime protections um + + align:start position:0% +people have overtime protections um + + + align:start position:0% +people have overtime protections um +making sure that people have paid leave + + align:start position:0% +making sure that people have paid leave + + + align:start position:0% +making sure that people have paid leave +the president just announced um + + align:start position:0% +the president just announced um + + + align:start position:0% +the president just announced um +initiatives to bolster paid leave in the + + align:start position:0% +initiatives to bolster paid leave in the + + + align:start position:0% +initiatives to bolster paid leave in the +United States those kinds of policies + + align:start position:0% +United States those kinds of policies + + + align:start position:0% +United States those kinds of policies +can help um ensure that even jobs that + + align:start position:0% +can help um ensure that even jobs that + + + align:start position:0% +can help um ensure that even jobs that +that that we have high quality jobs for + + align:start position:0% +that that we have high quality jobs for + + + align:start position:0% +that that we have high quality jobs for +people at all levels of Education and + + align:start position:0% +people at all levels of Education and + + + align:start position:0% +people at all levels of Education and +Training certainly important that we + + align:start position:0% +Training certainly important that we + + + align:start position:0% +Training certainly important that we +really help to improve those low wage + + align:start position:0% +really help to improve those low wage + + + align:start position:0% +really help to improve those low wage +jobs and provide career opportunities + + align:start position:0% +jobs and provide career opportunities + + + align:start position:0% +jobs and provide career opportunities +for growth and so on what else would you + + align:start position:0% +for growth and so on what else would you + + + align:start position:0% +for growth and so on what else would you +say that young people need to do to + + align:start position:0% +say that young people need to do to + + + align:start position:0% +say that young people need to do to +prepare for the good jobs of the future + + align:start position:0% +prepare for the good jobs of the future + + + align:start position:0% +prepare for the good jobs of the future +thinking about investments in your own + + align:start position:0% +thinking about investments in your own + + + align:start position:0% +thinking about investments in your own +training and education over the course + + align:start position:0% +training and education over the course + + + align:start position:0% +training and education over the course +of your career is just a really smart + + align:start position:0% +of your career is just a really smart + + + align:start position:0% +of your career is just a really smart +idea um one of the things people should + + align:start position:0% +idea um one of the things people should + + + align:start position:0% +idea um one of the things people should +be doing is asking their employers for + + align:start position:0% +be doing is asking their employers for + + + align:start position:0% +be doing is asking their employers for +what opportunities there are for + + align:start position:0% +what opportunities there are for + + + align:start position:0% +what opportunities there are for +advancement asking your union what can + + align:start position:0% +advancement asking your union what can + + + align:start position:0% +advancement asking your union what can +you do to help help support these kind + + align:start position:0% +you do to help help support these kind + + + align:start position:0% +you do to help help support these kind +of career ladders looking into things + + align:start position:0% +of career ladders looking into things + + + align:start position:0% +of career ladders looking into things +like joint Union and management programs + + align:start position:0% +like joint Union and management programs + + + align:start position:0% +like joint Union and management programs +that support these kind of career Lads + + align:start position:0% +that support these kind of career Lads + + + align:start position:0% +that support these kind of career Lads +for example there's there's programs + + align:start position:0% +for example there's there's programs + + + align:start position:0% +for example there's there's programs +that will help people go from a nursing + + align:start position:0% +that will help people go from a nursing + + + align:start position:0% +that will help people go from a nursing +assistant to an LPN to a registered + + align:start position:0% +assistant to an LPN to a registered + + + align:start position:0% +assistant to an LPN to a registered +nurse and if you can think of supporting + + align:start position:0% +nurse and if you can think of supporting + + + align:start position:0% +nurse and if you can think of supporting +those kinds of trajectories you can + + align:start position:0% +those kinds of trajectories you can + + + align:start position:0% +those kinds of trajectories you can +really carve out a career that you + + align:start position:0% +really carve out a career that you + + + align:start position:0% +really carve out a career that you +really lets let you punch punch the + + align:start position:0% +really lets let you punch punch the + + + align:start position:0% +really lets let you punch punch the +ticket to the middle class I think + + align:start position:0% +ticket to the middle class I think + + + align:start position:0% +ticket to the middle class I think +that's that's good advice uh young + + align:start position:0% +that's that's good advice uh young + + + align:start position:0% +that's that's good advice uh young +people have lots of opportunities and + + align:start position:0% +people have lots of opportunities and + + + align:start position:0% +people have lots of opportunities and +they have to create new ones uh along + + align:start position:0% +they have to create new ones uh along + + + align:start position:0% +they have to create new ones uh along +with the partnership of the Department + + align:start position:0% +with the partnership of the Department + + + align:start position:0% +with the partnership of the Department +of Labor and good employers and good + + align:start position:0% +of Labor and good employers and good + + + align:start position:0% +of Labor and good employers and good +labor organizations so thank you very + + align:start position:0% +labor organizations so thank you very + + + align:start position:0% +labor organizations so thank you very +much it's been my + + align:start position:0% + + + + align:start position:0% + +pleasure \ No newline at end of file diff --git a/9iJryWzLDIw.txt b/9iJryWzLDIw.txt new file mode 100644 index 0000000000000000000000000000000000000000..fa2abd84879393c2c6397b0fde5a27f0c74b63b0 --- /dev/null +++ b/9iJryWzLDIw.txt @@ -0,0 +1,7400 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +to view additional materials from + + align:start position:0% +to view additional materials from + + + align:start position:0% +to view additional materials from +hundreds of MIT courses visit MIT open + + align:start position:0% +hundreds of MIT courses visit MIT open + + + align:start position:0% +hundreds of MIT courses visit MIT open +courseware at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu okay so I've got Quiz 2 to + + align:start position:0% +ocw.mit.edu okay so I've got Quiz 2 to + + + align:start position:0% +ocw.mit.edu okay so I've got Quiz 2 to +give back to you with good scores so + + align:start position:0% +give back to you with good scores so + + + align:start position:0% +give back to you with good scores so +it's Christmas early uh or good work on + + align:start position:0% +it's Christmas early uh or good work on + + + align:start position:0% +it's Christmas early uh or good work on +that exam that's fine and uh so we all + + align:start position:0% +that exam that's fine and uh so we all + + + align:start position:0% +that exam that's fine and uh so we all +know 4A series is like a central topic + + align:start position:0% +know 4A series is like a central topic + + + align:start position:0% +know 4A series is like a central topic +on the final uh third of the course and + + align:start position:0% +on the final uh third of the course and + + + align:start position:0% +on the final uh third of the course and +I'll just keep going on 4 Series I'll + + align:start position:0% +I'll just keep going on 4 Series I'll + + + align:start position:0% +I'll just keep going on 4 Series I'll +give you a homework on 4.1 and + + align:start position:0% +give you a homework on 4.1 and + + + align:start position:0% +give you a homework on 4.1 and +4.2 so 4.1 is what we complete today the + + align:start position:0% +4.2 so 4.1 is what we complete today the + + + align:start position:0% +4.2 so 4.1 is what we complete today the +fora series 4.2 is the discret fora + + align:start position:0% +fora series 4.2 is the discret fora + + + align:start position:0% +fora series 4.2 is the discret fora +series uh so those are two major major + + align:start position:0% +series uh so those are two major major + + + align:start position:0% +series uh so those are two major major +topics for uh this part of the course + + align:start position:0% +topics for uh this part of the course + + + align:start position:0% +topics for uh this part of the course +the the this is the periodic one and 42 + + align:start position:0% +the the this is the periodic one and 42 + + + align:start position:0% +the the this is the periodic one and 42 +will be the finite one with a forier + + align:start position:0% +will be the finite one with a forier + + + align:start position:0% +will be the finite one with a forier +matrix showing up okay so can I pick up + + align:start position:0% +matrix showing up okay so can I pick up + + + align:start position:0% +matrix showing up okay so can I pick up +I made a list of topics last time to + + align:start position:0% +I made a list of topics last time to + + + align:start position:0% +I made a list of topics last time to +that that were important for 4.1 for 4A + + align:start position:0% +that that were important for 4.1 for 4A + + + align:start position:0% +that that were important for 4.1 for 4A +series and I think these are the + + align:start position:0% +series and I think these are the + + + align:start position:0% +series and I think these are the +remaining uh entries on the + + align:start position:0% +remaining uh entries on the + + + align:start position:0% +remaining uh entries on the +list uh I did the + + align:start position:0% +list uh I did the + + + align:start position:0% +list uh I did the +um the F series for the odd uh Square + + align:start position:0% +um the F series for the odd uh Square + + + align:start position:0% +um the F series for the odd uh Square +wave the minus one stepping up to plus + + align:start position:0% +wave the minus one stepping up to plus + + + align:start position:0% +wave the minus one stepping up to plus +one and you remember that uh well I'll + + align:start position:0% +one and you remember that uh well I'll + + + align:start position:0% +one and you remember that uh well I'll +just let me put that example down here + + align:start position:0% +just let me put that example down here + + + align:start position:0% +just let me put that example down here +that was the step function uh easier if + + align:start position:0% +that was the step function uh easier if + + + align:start position:0% +that was the step function uh easier if +I draw it than if I try to write + + align:start position:0% +I draw it than if I try to write + + + align:start position:0% +I draw it than if I try to write +equation so it was minus1 up to Plus one + + align:start position:0% +equation so it was minus1 up to Plus one + + + align:start position:0% +equation so it was minus1 up to Plus one +at Pi ending of course period 2 pi and I + + align:start position:0% +at Pi ending of course period 2 pi and I + + + align:start position:0% +at Pi ending of course period 2 pi and I +guess we called that S ofx for S + + align:start position:0% +guess we called that S ofx for S + + + align:start position:0% +guess we called that S ofx for S +signaling step function s signaling + + align:start position:0% +signaling step function s signaling + + + align:start position:0% +signaling step function s signaling +Square wave and S the general uh signal + + align:start position:0% +Square wave and S the general uh signal + + + align:start position:0% +Square wave and S the general uh signal +that the function is odd and that means + + align:start position:0% +that the function is odd and that means + + + align:start position:0% +that the function is odd and that means +that it goes with s functions and I + + align:start position:0% +that it goes with s functions and I + + + align:start position:0% +that it goes with s functions and I +think the amounts the numbers that we + + align:start position:0% +think the amounts the numbers that we + + + align:start position:0% +think the amounts the numbers that we +found from the formula was + + align:start position:0% +found from the formula was + + + align:start position:0% +found from the formula was +uh sin x over 1 sin 3x over 3 sin 5x + + align:start position:0% +uh sin x over 1 sin 3x over 3 sin 5x + + + align:start position:0% +uh sin x over 1 sin 3x over 3 sin 5x +over five that's it's just a great one + + align:start position:0% +over five that's it's just a great one + + + align:start position:0% +over five that's it's just a great one +to + + align:start position:0% + + + + align:start position:0% + +remember yeah and that's the the uh uh + + align:start position:0% +remember yeah and that's the the uh uh + + + align:start position:0% +remember yeah and that's the the uh uh +the example that has the the important + + align:start position:0% +the example that has the the important + + + align:start position:0% +the example that has the the important +and I don't know if I wrote down Gibb's + + align:start position:0% +and I don't know if I wrote down Gibb's + + + align:start position:0% +and I don't know if I wrote down Gibb's +name he was the great physicist at Yale + + align:start position:0% +name he was the great physicist at Yale + + + align:start position:0% +name he was the great physicist at Yale +uh well 100 years ago or more and uh did + + align:start position:0% +uh well 100 years ago or more and uh did + + + align:start position:0% +uh well 100 years ago or more and uh did +uh this key idea in that that appears + + align:start position:0% +uh this key idea in that that appears + + + align:start position:0% +uh this key idea in that that appears +all the time that anytime you have a + + align:start position:0% +all the time that anytime you have a + + + align:start position:0% +all the time that anytime you have a +step function then the Fier Series has a + + align:start position:0% +step function then the Fier Series has a + + + align:start position:0% +step function then the Fier Series has a +well it does its + + align:start position:0% +well it does its + + + align:start position:0% +well it does its +best if I take a thousand terms it'll do + + align:start position:0% +best if I take a thousand terms it'll do + + + align:start position:0% +best if I take a thousand terms it'll do +its best but it will overshoot by an + + align:start position:0% +its best but it will overshoot by an + + + align:start position:0% +its best but it will overshoot by an +amount that Gibbs found and then it will + + align:start position:0% +amount that Gibbs found and then it will + + + align:start position:0% +amount that Gibbs found and then it will +get really close CL and then it will + + align:start position:0% +get really close CL and then it will + + + align:start position:0% +get really close CL and then it will +overshoot again and and then + + align:start position:0% +overshoot again and and then + + + align:start position:0% +overshoot again and and then +symmetrically or anti- symmetrically I + + align:start position:0% +symmetrically or anti- symmetrically I + + + align:start position:0% +symmetrically or anti- symmetrically I +should say so that's the Gibbs + + align:start position:0% +should say so that's the Gibbs + + + align:start position:0% +should say so that's the Gibbs +phenomenon of great importance okay I I + + align:start position:0% +phenomenon of great importance okay I I + + + align:start position:0% +phenomenon of great importance okay I I +write this one out because uh first it's + + align:start position:0% +write this one out because uh first it's + + + align:start position:0% +write this one out because uh first it's +a important one to remember uh second + + align:start position:0% +a important one to remember uh second + + + align:start position:0% +a important one to remember uh second +it'll give us a good example for this uh + + align:start position:0% +it'll give us a good example for this uh + + + align:start position:0% +it'll give us a good example for this uh +important equality uh that the energy in + + align:start position:0% +important equality uh that the energy in + + + align:start position:0% +important equality uh that the energy in +in in the function is the energy in the + + align:start position:0% +in in the function is the energy in the + + + align:start position:0% +in in the function is the energy in the +coefficients that'll be good okay + + align:start position:0% +coefficients that'll be good okay + + + align:start position:0% +coefficients that'll be good okay +actually maybe I should do that one + + align:start position:0% +actually maybe I should do that one + + + align:start position:0% +actually maybe I should do that one +first because the the Delta function has + + align:start position:0% +first because the the Delta function has + + + align:start position:0% +first because the the Delta function has +got infinite energy and and we don't + + align:start position:0% +got infinite energy and and we don't + + + align:start position:0% +got infinite energy and and we don't +learn anything from this equation so so + + align:start position:0% +learn anything from this equation so so + + + align:start position:0% +learn anything from this equation so so +let me let me jump to the energy in the + + align:start position:0% +let me let me jump to the energy in the + + + align:start position:0% +let me let me jump to the energy in the +function and the energy in the + + align:start position:0% +function and the energy in the + + + align:start position:0% +function and the energy in the +coefficients so what do I mean by + + align:start position:0% +coefficients so what do I mean by + + + align:start position:0% +coefficients so what do I mean by +energy well it's quadratic right that's + + align:start position:0% +energy well it's quadratic right that's + + + align:start position:0% +energy well it's quadratic right that's +it's the it's the it's the length + + align:start position:0% +it's the it's the it's the length + + + align:start position:0% +it's the it's the it's the length +squared here it's the length squar of + + align:start position:0% +squared here it's the length squar of + + + align:start position:0% +squared here it's the length squar of +the function so uh let me uh compute + + align:start position:0% +the function so uh let me uh compute + + + align:start position:0% +the function so uh let me uh compute +maybe I'll do it on this board + + align:start position:0% +maybe I'll do it on this board + + + align:start position:0% +maybe I'll do it on this board +underneath and leave space for the Delta + + align:start position:0% +underneath and leave space for the Delta + + + align:start position:0% +underneath and leave space for the Delta +function the energy in X space is just + + align:start position:0% +function the energy in X space is just + + + align:start position:0% +function the energy in X space is just +the integral it's the length squared the + + align:start position:0% +the integral it's the length squared the + + + align:start position:0% +the integral it's the length squared the +integral of s ofx + + align:start position:0% +integral of s ofx + + + align:start position:0% +integral of s ofx +squar + + align:start position:0% +squar + + + align:start position:0% +squar +DX it's just just what you + + align:start position:0% +DX it's just just what you + + + align:start position:0% +DX it's just just what you +would uh + + align:start position:0% + + + + align:start position:0% + +expect we have a function not a vector + + align:start position:0% +expect we have a function not a vector + + + align:start position:0% +expect we have a function not a vector +so we can't + + align:start position:0% +so we can't + + + align:start position:0% +so we can't +sum coefficient squared we instead we + + align:start position:0% +sum coefficient squared we instead we + + + align:start position:0% +sum coefficient squared we instead we +integrate all the values squared and of + + align:start position:0% +integrate all the values squared and of + + + align:start position:0% +integrate all the values squared and of +course this is a number that we can + + align:start position:0% +course this is a number that we can + + + align:start position:0% +course this is a number that we can +quickly compute for that function so + + align:start position:0% +quickly compute for that function so + + + align:start position:0% +quickly compute for that function so +what does it turn out to be well what is + + align:start position:0% +what does it turn out to be well what is + + + align:start position:0% +what does it turn out to be well what is +s ofx s for that + + align:start position:0% +s ofx s for that + + + align:start position:0% +s ofx s for that +function one obviously the function is + + align:start position:0% +function one obviously the function is + + + align:start position:0% +function one obviously the function is +one here I'm looking at the original s + + align:start position:0% +one here I'm looking at the original s + + + align:start position:0% +one here I'm looking at the original s +ofx not the + + align:start position:0% +ofx not the + + + align:start position:0% +ofx not the +series the function is one there and + + align:start position:0% +series the function is one there and + + + align:start position:0% +series the function is one there and +minus one there when I Square those It's + + align:start position:0% +minus one there when I Square those It's + + + align:start position:0% +minus one there when I Square those It's +s of x^2 is one everywhere so I'm + + align:start position:0% +s of x^2 is one everywhere so I'm + + + align:start position:0% +s of x^2 is one everywhere so I'm +integrating one everywhere from minus pi + + align:start position:0% +integrating one everywhere from minus pi + + + align:start position:0% +integrating one everywhere from minus pi +to Pi so I get the answer 2 + + align:start position:0% +to Pi so I get the answer 2 + + + align:start position:0% +to Pi so I get the answer 2 +pi so that's a case where the energy in + + align:start position:0% +pi so that's a case where the energy in + + + align:start position:0% +pi so that's a case where the energy in +the physical space the X space was + + align:start position:0% +the physical space the X space was + + + align:start position:0% +the physical space the X space was +totally easy to compute now what about + + align:start position:0% +totally easy to compute now what about + + + align:start position:0% +totally easy to compute now what about +energy what is this equality this this + + align:start position:0% +energy what is this equality this this + + + align:start position:0% +energy what is this equality this this +really neat easy to remember equality + + align:start position:0% +really neat easy to remember equality + + + align:start position:0% +really neat easy to remember equality +it's what's the I I'm just going to find + + align:start position:0% +it's what's the I I'm just going to find + + + align:start position:0% +it's what's the I I'm just going to find +it + + align:start position:0% +it + + + align:start position:0% +it +by looking by taking this thing squared + + align:start position:0% +by looking by taking this thing squared + + + align:start position:0% +by looking by taking this thing squared +what's the integral of the right hand + + align:start position:0% +what's the integral of the right hand + + + align:start position:0% +what's the integral of the right hand +side the two are + + align:start position:0% +side the two are + + + align:start position:0% +side the two are +equal + + align:start position:0% +equal + + + align:start position:0% +equal +so I suppose I just fire away I + + align:start position:0% +so I suppose I just fire away I + + + align:start position:0% +so I suppose I just fire away I +integrate the square of that infinite + + align:start position:0% +integrate the square of that infinite + + + align:start position:0% +integrate the square of that infinite +series you're going to say well that's + + align:start position:0% +series you're going to say well that's + + + align:start position:0% +series you're going to say well that's +going to take a while but uh uh uh + + align:start position:0% +going to take a while but uh uh uh + + + align:start position:0% +going to take a while but uh uh uh +what's going to be good the the key + + align:start position:0% +what's going to be good the the key + + + align:start position:0% +what's going to be good the the key +point the first point in in in last + + align:start position:0% +point the first point in in in last + + + align:start position:0% +point the first point in in in last +times's lecture the first point in every + + align:start position:0% +times's lecture the first point in every + + + align:start position:0% +times's lecture the first point in every +discussion of Fier series is + + align:start position:0% +discussion of Fier series is + + + align:start position:0% +discussion of Fier series is +orthogonality signs times other signs + + align:start position:0% +orthogonality signs times other signs + + + align:start position:0% +orthogonality signs times other signs +integrated are zero so that a whole lot + + align:start position:0% +integrated are zero so that a whole lot + + + align:start position:0% +integrated are zero so that a whole lot +of terms will go so I take that thing I + + align:start position:0% +of terms will go so I take that thing I + + + align:start position:0% +of terms will go so I take that thing I +Square it so let me uh let me do that + + align:start position:0% +Square it so let me uh let me do that + + + align:start position:0% +Square it so let me uh let me do that +one here the inte from minus pi to Pi + + align:start position:0% +one here the inte from minus pi to Pi + + + align:start position:0% +one here the inte from minus pi to Pi +may I take out the 4 over pi^ squar + + align:start position:0% + + + + align:start position:0% + +just so I don't have it so it's not + + align:start position:0% +just so I don't have it so it's not + + + align:start position:0% +just so I don't have it so it's not +confusing the now this is the s x over 1 + + align:start position:0% +confusing the now this is the s x over 1 + + + align:start position:0% +confusing the now this is the s x over 1 +sin 3x over 3 sin KX over K and so on + + align:start position:0% +sin 3x over 3 sin KX over K and so on + + + align:start position:0% +sin 3x over 3 sin KX over K and so on +all squared DX and so what do I get the + + align:start position:0% +all squared DX and so what do I get the + + + align:start position:0% +all squared DX and so what do I get the +4 over pi + + align:start position:0% + + + + align:start position:0% + +squar and now I've got a whole lot of + + align:start position:0% +squar and now I've got a whole lot of + + + align:start position:0% +squar and now I've got a whole lot of +terms + + align:start position:0% +terms + + + align:start position:0% +terms +but the thing is I can do this because + + align:start position:0% +but the thing is I can do this because + + + align:start position:0% +but the thing is I can do this because +when I Square this I'll have a lot of + + align:start position:0% +when I Square this I'll have a lot of + + + align:start position:0% +when I Square this I'll have a lot of +terms like sinx sin 3x and when I + + align:start position:0% +terms like sinx sin 3x and when I + + + align:start position:0% +terms like sinx sin 3x and when I +integrate those I get zero so the only + + align:start position:0% +integrate those I get zero so the only + + + align:start position:0% +integrate those I get zero so the only +ones that I don't get zero are when sinx + + align:start position:0% +ones that I don't get zero are when sinx + + + align:start position:0% +ones that I don't get zero are when sinx +integrates against itself and sin 3x + + align:start position:0% +integrates against itself and sin 3x + + + align:start position:0% +integrates against itself and sin 3x +against itself so when sin x integrates + + align:start position:0% +against itself so when sin x integrates + + + align:start position:0% +against itself so when sin x integrates +against itself that's sin squared its + + align:start position:0% +against itself that's sin squared its + + + align:start position:0% +against itself that's sin squared its +integral is you remember the integral of + + align:start position:0% +integral is you remember the integral of + + + align:start position:0% +integral is you remember the integral of +sin squared which is + + align:start position:0% +sin squared which is + + + align:start position:0% +sin squared which is +it's it's its average value is a half + + align:start position:0% +it's it's its average value is a half + + + align:start position:0% +it's it's its average value is a half +we're over an interval I think I'm going + + align:start position:0% +we're over an interval I think I'm going + + + align:start position:0% +we're over an interval I think I'm going +to get Pi for S squared because sin + + align:start position:0% +to get Pi for S squared because sin + + + align:start position:0% +to get Pi for S squared because sin +squar we could do that calculation + + align:start position:0% +squar we could do that calculation + + + align:start position:0% +squar we could do that calculation +separately it's a standard integral the + + align:start position:0% +separately it's a standard integral the + + + align:start position:0% +separately it's a standard integral the +integral of sin squar is pi actually + + align:start position:0% +integral of sin squar is pi actually + + + align:start position:0% +integral of sin squar is pi actually +yeah it it just uses the fact that sin^2 + + align:start position:0% +yeah it it just uses the fact that sin^2 + + + align:start position:0% +yeah it it just uses the fact that sin^2 +X is the same as whatever it is the same + + align:start position:0% +X is the same as whatever it is the same + + + align:start position:0% +X is the same as whatever it is the same +as U is it + + align:start position:0% + + + + align:start position:0% + +one minus cosine 2X or something over + + align:start position:0% +one minus cosine 2X or something over + + + align:start position:0% +one minus cosine 2X or something over +two or plus who cares because the yeah + + align:start position:0% +two or plus who cares because the yeah + + + align:start position:0% +two or plus who cares because the yeah +because the integral of whichever plus + + align:start position:0% +because the integral of whichever plus + + + align:start position:0% +because the integral of whichever plus +or minus let + + align:start position:0% +or minus let + + + align:start position:0% +or minus let +me well I suppose for history sake we + + align:start position:0% +me well I suppose for history sake we + + + align:start position:0% +me well I suppose for history sake we +should get it right which is it is it a + + align:start position:0% +should get it right which is it is it a + + + align:start position:0% +should get it right which is it is it a +minus so it's looks okay now okay all + + align:start position:0% +minus so it's looks okay now okay all + + + align:start position:0% +minus so it's looks okay now okay all +right if it's wrong I didn't say it's + + align:start position:0% +right if it's wrong I didn't say it's + + + align:start position:0% +right if it's wrong I didn't say it's +wrong okay but I'm going to integrate so + + align:start position:0% +wrong okay but I'm going to integrate so + + + align:start position:0% +wrong okay but I'm going to integrate so +the co integral the cosine is z Z and + + align:start position:0% +the co integral the cosine is z Z and + + + align:start position:0% +the co integral the cosine is z Z and +the integral of the 1/2 is the part that + + align:start position:0% +the integral of the 1/2 is the part that + + + align:start position:0% +the integral of the 1/2 is the part that +the part I'm talking about that 1/2 is + + align:start position:0% +the part I'm talking about that 1/2 is + + + align:start position:0% +the part I'm talking about that 1/2 is +there all the way from minus pi to Pi so + + align:start position:0% +there all the way from minus pi to Pi so + + + align:start position:0% +there all the way from minus pi to Pi so +I get a PI from all these signs and now + + align:start position:0% +I get a PI from all these signs and now + + + align:start position:0% +I get a PI from all these signs and now +what are the what are all the terms well + + align:start position:0% +what are the what are all the terms well + + + align:start position:0% +what are the what are all the terms well +one over one + + align:start position:0% + + + + align:start position:0% + +squar that just had a coefficient one + + align:start position:0% +squar that just had a coefficient one + + + align:start position:0% +squar that just had a coefficient one +but what's the next guy you remember I'm + + align:start position:0% +but what's the next guy you remember I'm + + + align:start position:0% +but what's the next guy you remember I'm +squaring it I'm integrating but I have a + + align:start position:0% +squaring it I'm integrating but I have a + + + align:start position:0% +squaring it I'm integrating but I have a +1 over3 + + align:start position:0% +1 over3 + + + align:start position:0% +1 over3 +squar and one over 5^ s and so + + align:start position:0% +squar and one over 5^ s and so + + + align:start position:0% +squar and one over 5^ s and so +on okay and here's the PO great Point + + align:start position:0% +on okay and here's the PO great Point + + + align:start position:0% +on okay and here's the PO great Point +these two are + + align:start position:0% +these two are + + + align:start position:0% +these two are +equal I I I've got the same function + + align:start position:0% +equal I I I've got the same function + + + align:start position:0% +equal I I I've got the same function +expressed in X space and here it's + + align:start position:0% +expressed in X space and here it's + + + align:start position:0% +expressed in X space and here it's +expressed in sign space you could say in + + align:start position:0% +expressed in sign space you could say in + + + align:start position:0% +expressed in sign space you could say in +in in harmonic space okay so that's + + align:start position:0% +in in harmonic space okay so that's + + + align:start position:0% +in in harmonic space okay so that's +equal and and that's the going to be the + + align:start position:0% +equal and and that's the going to be the + + + align:start position:0% +equal and and that's the going to be the +fact in general that the in general that + + align:start position:0% +fact in general that the in general that + + + align:start position:0% +fact in general that the in general that +the integral of s of X squar I mean so + + align:start position:0% +the integral of s of X squar I mean so + + + align:start position:0% +the integral of s of X squar I mean so +the general fact will be the integral of + + align:start position:0% +the general fact will be the integral of + + + align:start position:0% +the general fact will be the integral of +s of well I'll write it down below but + + align:start position:0% +s of well I'll write it down below but + + + align:start position:0% +s of well I'll write it down below but +let let's just see what we get for + + align:start position:0% +let let's just see what we get for + + + align:start position:0% +let let's just see what we get for +numbers here so I had Pi on both + + align:start position:0% +numbers here so I had Pi on both + + + align:start position:0% +numbers here so I had Pi on both +sides and so if I lift that over there I + + align:start position:0% +sides and so if I lift that over there I + + + align:start position:0% +sides and so if I lift that over there I +get something like what do I have pi^ + + align:start position:0% +get something like what do I have pi^ + + + align:start position:0% +get something like what do I have pi^ +squar over 16 maybe I have pi^ squ over + + align:start position:0% +squar over 16 maybe I have pi^ squ over + + + align:start position:0% +squar over 16 maybe I have pi^ squ over +8 you just get like an + + align:start position:0% +8 you just get like an + + + align:start position:0% +8 you just get like an +amazing a remarkable formula putting + + align:start position:0% +amazing a remarkable formula putting + + + align:start position:0% +amazing a remarkable formula putting +that up there would be pi^ S over 16 and + + align:start position:0% +that up there would be pi^ S over 16 and + + + align:start position:0% +that up there would be pi^ S over 16 and +the two makes it an eight and here I + + align:start position:0% +the two makes it an eight and here I + + + align:start position:0% +the two makes it an eight and here I +have the sum of 1 over 1^ 2 + 1 over 3^ + + align:start position:0% +have the sum of 1 over 1^ 2 + 1 over 3^ + + + align:start position:0% +have the sum of 1 over 1^ 2 + 1 over 3^ +2 + 1 over 5^ squ so you know that + + align:start position:0% +2 + 1 over 5^ squ so you know that + + + align:start position:0% +2 + 1 over 5^ squ so you know that +that's a an infinite sum that I would + + align:start position:0% +that's a an infinite sum that I would + + + align:start position:0% +that's a an infinite sum that I would +not have known how to how to + + align:start position:0% +not have known how to how to + + + align:start position:0% +not have known how to how to +do except it it appears here the sum of + + align:start position:0% +do except it it appears here the sum of + + + align:start position:0% +do except it it appears here the sum of +one over all those + + align:start position:0% +one over all those + + + align:start position:0% +one over all those +squares if I T picked another example I + + align:start position:0% +squares if I T picked another example I + + + align:start position:0% +squares if I T picked another example I +could get the sum oh this was all the + + align:start position:0% +could get the sum oh this was all the + + + align:start position:0% +could get the sum oh this was all the +odd numberers squared uh if I picked a + + align:start position:0% +odd numberers squared uh if I picked a + + + align:start position:0% +odd numberers squared uh if I picked a +different function I could have got one + + align:start position:0% +different function I could have got one + + + align:start position:0% +different function I could have got one +that that had all + + align:start position:0% +that that had all + + + align:start position:0% +that that had all +the that that also had the sin 2x over 2 + + align:start position:0% +the that that also had the sin 2x over 2 + + + align:start position:0% +the that that also had the sin 2x over 2 +and the sin 4X over 4 so this would have + + align:start position:0% +and the sin 4X over 4 so this would have + + + align:start position:0% +and the sin 4X over 4 so this would have +been the sum of all the squares do you + + align:start position:0% +been the sum of all the squares do you + + + align:start position:0% +been the sum of all the squares do you +know happen to know what that comes out + + align:start position:0% +know happen to know what that comes out + + + align:start position:0% +know happen to know what that comes out +to be I mean it's here's a way to + + align:start position:0% +to be I mean it's here's a way to + + + align:start position:0% +to be I mean it's here's a way to +compute Pi we have a formula for pi here + + align:start position:0% +compute Pi we have a formula for pi here + + + align:start position:0% +compute Pi we have a formula for pi here +uh and and we'd have another formula + + align:start position:0% +uh and and we'd have another formula + + + align:start position:0% +uh and and we'd have another formula +that involved all the spons maybe I have + + align:start position:0% +that involved all the spons maybe I have + + + align:start position:0% +that involved all the spons maybe I have +room for it up here this this would be + + align:start position:0% +room for it up here this this would be + + + align:start position:0% +room for it up here this this would be +the sum of 1 over n^2 right if if I had + + align:start position:0% +the sum of 1 over n^2 right if if I had + + + align:start position:0% +the sum of 1 over n^2 right if if I had +all this here I have only the odd ones + + align:start position:0% +all this here I have only the odd ones + + + align:start position:0% +all this here I have only the odd ones +and I get pi^ 2 over 8 you happen to + + align:start position:0% +and I get pi^ 2 over 8 you happen to + + + align:start position:0% +and I get pi^ 2 over 8 you happen to +know what I get for for the all of them + + align:start position:0% +know what I get for for the all of them + + + align:start position:0% +know what I get for for the all of them +the E you know so I'm also including one + + align:start position:0% +the E you know so I'm also including one + + + align:start position:0% +the E you know so I'm also including one +over two squar there's a quarter also in + + align:start position:0% +over two squar there's a quarter also in + + + align:start position:0% +over two squar there's a quarter also in +here and also a 16th and also a 36 in in + + align:start position:0% +here and also a 16th and also a 36 in in + + + align:start position:0% +here and also a 16th and also a 36 in in +this one and the answer happens to be + + align:start position:0% +this one and the answer happens to be + + + align:start position:0% +this one and the answer happens to be +pi^ 2 over 6 + + align:start position:0% +pi^ 2 over 6 + + + align:start position:0% +pi^ 2 over 6 +pi^ 2 over + + align:start position:0% +pi^ 2 over + + + align:start position:0% +pi^ 2 over +6 yeah so that's + + align:start position:0% +6 yeah so that's + + + align:start position:0% +6 yeah so that's +you it's nice I mean the the important + + align:start position:0% +you it's nice I mean the the important + + + align:start position:0% +you it's nice I mean the the important +point about this energy equality is not + + align:start position:0% +point about this energy equality is not + + + align:start position:0% +point about this energy equality is not +being able to get a few very remarkable + + align:start position:0% +being able to get a few very remarkable + + + align:start position:0% +being able to get a few very remarkable +formulas for pi uh and and there's will + + align:start position:0% +formulas for pi uh and and there's will + + + align:start position:0% +formulas for pi uh and and there's will +be another remarkable formula in the + + align:start position:0% +be another remarkable formula in the + + + align:start position:0% +be another remarkable formula in the +homework uh this is a little famous do + + align:start position:0% +homework uh this is a little famous do + + + align:start position:0% +homework uh this is a little famous do +you know what the what this is is this + + align:start position:0% +you know what the what this is is this + + + align:start position:0% +you know what the what this is is this +is the this is the famous reman zeta + + align:start position:0% +is the this is the famous reman zeta + + + align:start position:0% +is the this is the famous reman zeta +function one the sum of 1/ N to the x is + + align:start position:0% +function one the sum of 1/ N to the x is + + + align:start position:0% +function one the sum of 1/ N to the x is +the zeta function at X here's the zeta + + align:start position:0% +the zeta function at X here's the zeta + + + align:start position:0% +the zeta function at X here's the zeta +function at two so if I could draw a + + align:start position:0% +function at two so if I could draw a + + + align:start position:0% +function at two so if I could draw a +Zeta + + align:start position:0% + + + + align:start position:0% + +maybe I there are some Greek guys in + + align:start position:0% +maybe I there are some Greek guys in + + + align:start position:0% +maybe I there are some Greek guys in +this class who could do it properly but + + align:start position:0% +this class who could do it properly but + + + align:start position:0% +this class who could do it properly but +anyway HH look how chicken out + + align:start position:0% +anyway HH look how chicken out + + + align:start position:0% +anyway HH look how chicken out +Zeta of of at the value two right Z of + + align:start position:0% +Zeta of of at the value two right Z of + + + align:start position:0% +Zeta of of at the value two right Z of +two so we know Z of two we know Z of + + align:start position:0% +two so we know Z of two we know Z of + + + align:start position:0% +two so we know Z of two we know Z of +four I don't think we know Z of three it + + align:start position:0% +four I don't think we know Z of three it + + + align:start position:0% +four I don't think we know Z of three it +doesn't come it's not a I think it's not + + align:start position:0% +doesn't come it's not a I think it's not + + + align:start position:0% +doesn't come it's not a I think it's not +a a special number like pi^ squ over 6 + + align:start position:0% +a a special number like pi^ squ over 6 + + + align:start position:0% +a a special number like pi^ squ over 6 +um so the zeta function the sum over one + + align:start position:0% +um so the zeta function the sum over one + + + align:start position:0% +um so the zeta function the sum over one +to the one over n to this thing is uh + + align:start position:0% +to the one over n to this thing is uh + + + align:start position:0% +to the one over n to this thing is uh +that's the actually that's the subject + + align:start position:0% +that's the actually that's the subject + + + align:start position:0% +that's the actually that's the subject +of a a problem that remond did not solve + + align:start position:0% +of a a problem that remond did not solve + + + align:start position:0% +of a a problem that remond did not solve +there's a problem reman did not solve + + align:start position:0% +there's a problem reman did not solve + + + align:start position:0% +there's a problem reman did not solve +and nobody has succeeded to find it to + + align:start position:0% +and nobody has succeeded to find it to + + + align:start position:0% +and nobody has succeeded to find it to +solve it + + align:start position:0% +solve it + + + align:start position:0% +solve it +since there's a million doll prize for + + align:start position:0% +since there's a million doll prize for + + + align:start position:0% +since there's a million doll prize for +its + + align:start position:0% +its + + + align:start position:0% +its +solution um my neighbors think I should + + align:start position:0% +solution um my neighbors think I should + + + align:start position:0% +solution um my neighbors think I should +be working on this but I know better uh + + align:start position:0% +be working on this but I know better uh + + + align:start position:0% +be working on this but I know better uh +uh it's going to be solved one day but + + align:start position:0% +uh it's going to be solved one day but + + + align:start position:0% +uh it's going to be solved one day but +uh it's pretty difficult and that is to + + align:start position:0% +uh it's pretty difficult and that is to + + + align:start position:0% +uh it's pretty difficult and that is to +know where this Z function where it it's + + align:start position:0% +know where this Z function where it it's + + + align:start position:0% +know where this Z function where it it's +zero of course it isn't zero at two + + align:start position:0% +zero of course it isn't zero at two + + + align:start position:0% +zero of course it isn't zero at two +because it's pi^ squ over 6 and actually + + align:start position:0% +because it's pi^ squ over 6 and actually + + + align:start position:0% +because it's pi^ squ over 6 and actually +it's the conjecture is that it's zero + + align:start position:0% +it's the conjecture is that it's zero + + + align:start position:0% +it's the conjecture is that it's zero +all the zeros have are at points complex + + align:start position:0% +all the zeros have are at points complex + + + align:start position:0% +all the zeros have are at points complex +numbers with real part a half so they're + + align:start position:0% +numbers with real part a half so they're + + + align:start position:0% +numbers with real part a half so they're +on this famous line uh the imaginary + + align:start position:0% +on this famous line uh the imaginary + + + align:start position:0% +on this famous line uh the imaginary +line with real part a half and uh that's + + align:start position:0% +line with real part a half and uh that's + + + align:start position:0% +line with real part a half and uh that's +a that that's a the most important + + align:start position:0% +a that that's a the most important + + + align:start position:0% +a that that's a the most important +problem in pure mathematics actually + + align:start position:0% +problem in pure mathematics actually + + + align:start position:0% +problem in pure mathematics actually +yeah so here we go we got we got a + + align:start position:0% +yeah so here we go we got we got a + + + align:start position:0% +yeah so here we go we got we got a +formula for pi out of this energy + + align:start position:0% +formula for pi out of this energy + + + align:start position:0% +formula for pi out of this energy +identity and I'll write it again in the + + align:start position:0% +identity and I'll write it again in the + + + align:start position:0% +identity and I'll write it again in the +once I have the complex + + align:start position:0% +once I have the complex + + + align:start position:0% +once I have the complex +form + + align:start position:0% +form + + + align:start position:0% +form +okay so but you see where it comes from + + align:start position:0% +okay so but you see where it comes from + + + align:start position:0% +okay so but you see where it comes from +it just comes from orthogonality that + + align:start position:0% +it just comes from orthogonality that + + + align:start position:0% +it just comes from orthogonality that +the fact that we could integrate that + + align:start position:0% +the fact that we could integrate that + + + align:start position:0% +the fact that we could integrate that +square is the is is what what made it + + align:start position:0% +square is the is is what what made it + + + align:start position:0% +square is the is is what what made it +all work okay let's do uh the Delta + + align:start position:0% +all work okay let's do uh the Delta + + + align:start position:0% +all work okay let's do uh the Delta +function okay so that's an even function + + align:start position:0% +function okay so that's an even function + + + align:start position:0% +function okay so that's an even function +the Delta right now I'm looking at the + + align:start position:0% +the Delta right now I'm looking at the + + + align:start position:0% +the Delta right now I'm looking at the +Delta function us pi to Pi it has the + + align:start position:0% +Delta function us pi to Pi it has the + + + align:start position:0% +Delta function us pi to Pi it has the +spike at + + align:start position:0% +spike at + + + align:start position:0% +spike at +zero and it's certainly even so we'll we + + align:start position:0% +zero and it's certainly even so we'll we + + + align:start position:0% +zero and it's certainly even so we'll we +expect cosiness and what are the + + align:start position:0% +expect cosiness and what are the + + + align:start position:0% +expect cosiness and what are the +coefficients so it's just uh it's just + + align:start position:0% +coefficients so it's just uh it's just + + + align:start position:0% +coefficients so it's just uh it's just +important one to know very important + + align:start position:0% +important one to know very important + + + align:start position:0% +important one to know very important +example uh so what's a not in general + + align:start position:0% +example uh so what's a not in general + + + align:start position:0% +example uh so what's a not in general +the coefficient a not in the Fier series + + align:start position:0% +the coefficient a not in the Fier series + + + align:start position:0% +the coefficient a not in the Fier series +is + + align:start position:0% +is + + + align:start position:0% +is +the if I have a function Delta of x s + + align:start position:0% +the if I have a function Delta of x s + + + align:start position:0% +the if I have a function Delta of x s +ofx whatever my function the a not + + align:start position:0% +ofx whatever my function the a not + + + align:start position:0% +ofx whatever my function the a not +coefficient is the average a for average + + align:start position:0% +coefficient is the average a for average + + + align:start position:0% +coefficient is the average a for average +there a not is the average value so what + + align:start position:0% +there a not is the average value so what + + + align:start position:0% +there a not is the average value so what +is so this has the this is 1 over 2 pi + + align:start position:0% +is so this has the this is 1 over 2 pi + + + align:start position:0% +is so this has the this is 1 over 2 pi +the integral from minus pi to Pi of my + + align:start position:0% + + + + align:start position:0% + +function where did that come from I just + + align:start position:0% +function where did that come from I just + + + align:start position:0% +function where did that come from I just +integrate I just multiply both sides by + + align:start position:0% +integrate I just multiply both sides by + + + align:start position:0% +integrate I just multiply both sides by +one and and or or by 1 over two pi and + + align:start position:0% +one and and or or by 1 over two pi and + + + align:start position:0% +one and and or or by 1 over two pi and +integrated it + + align:start position:0% +integrated it + + + align:start position:0% +integrated it +and all those terms disappeared and I + + align:start position:0% +and all those terms disappeared and I + + + align:start position:0% +and all those terms disappeared and I +was left with a not and what's the + + align:start position:0% +was left with a not and what's the + + + align:start position:0% +was left with a not and what's the +answer everybody knows that + + align:start position:0% +answer everybody knows that + + + align:start position:0% +answer everybody knows that +integral the integral of the Delta + + align:start position:0% +integral the integral of the Delta + + + align:start position:0% +integral the integral of the Delta +function is one so I just get one over 2 + + align:start position:0% +function is one so I just get one over 2 + + + align:start position:0% +function is one so I just get one over 2 +pi so one over 2 pi okay now ready for + + align:start position:0% +pi so one over 2 pi okay now ready for + + + align:start position:0% +pi so one over 2 pi okay now ready for +A1 how much how much of cosine X do I + + align:start position:0% +A1 how much how much of cosine X do I + + + align:start position:0% +A1 how much how much of cosine X do I +have can I just change this formula to + + align:start position:0% +have can I just change this formula to + + + align:start position:0% +have can I just change this formula to +to give me A1 and you can tell me what + + align:start position:0% +to give me A1 and you can tell me what + + + align:start position:0% +to give me A1 and you can tell me what +it gives well let me do it do it here + + align:start position:0% +it gives well let me do it do it here + + + align:start position:0% +it gives well let me do it do it here +here's A1 + + align:start position:0% +here's A1 + + + align:start position:0% +here's A1 +what's the formula for + + align:start position:0% +what's the formula for + + + align:start position:0% +what's the formula for +A1 it's just like B1 like the sign + + align:start position:0% +A1 it's just like B1 like the sign + + + align:start position:0% +A1 it's just like B1 like the sign +formulas you have to remember you're + + align:start position:0% +formulas you have to remember you're + + + align:start position:0% +formulas you have to remember you're +only dividing by pi because that average + + align:start position:0% +only dividing by pi because that average + + + align:start position:0% +only dividing by pi because that average +value was a half as we saw and you then + + align:start position:0% +value was a half as we saw and you then + + + align:start position:0% +value was a half as we saw and you then +you have the integral of whatever your + + align:start position:0% +you have the integral of whatever your + + + align:start position:0% +you have the integral of whatever your +function is Delta of X in this case + + align:start position:0% +function is Delta of X in this case + + + align:start position:0% +function is Delta of X in this case +times the cosine of 1x if we're looking + + align:start position:0% +times the cosine of 1x if we're looking + + + align:start position:0% +times the cosine of 1x if we're looking +for A1 we've multiplied about both sides + + align:start position:0% +for A1 we've multiplied about both sides + + + align:start position:0% +for A1 we've multiplied about both sides +by cos x and integrated and what what + + align:start position:0% +by cos x and integrated and what what + + + align:start position:0% +by cos x and integrated and what what +answer do we + + align:start position:0% + + + + align:start position:0% + +get for + + align:start position:0% +get for + + + align:start position:0% +get for +A1 what's the integral of Delta of X + + align:start position:0% +A1 what's the integral of Delta of X + + + align:start position:0% +A1 what's the integral of Delta of X +time cosine + + align:start position:0% +time cosine + + + align:start position:0% +time cosine +X DX which I should put in a DX and the + + align:start position:0% +X DX which I should put in a DX and the + + + align:start position:0% +X DX which I should put in a DX and the +answer is one also one the Delta + + align:start position:0% +answer is one also one the Delta + + + align:start position:0% +answer is one also one the Delta +function this Spike picks out the value + + align:start position:0% +function this Spike picks out the value + + + align:start position:0% +function this Spike picks out the value +of this function at the + + align:start position:0% +of this function at the + + + align:start position:0% +of this function at the +spike because of course it doesn't + + align:start position:0% +spike because of course it doesn't + + + align:start position:0% +spike because of course it doesn't +matter what that function is away from + + align:start position:0% +matter what that function is away from + + + align:start position:0% +matter what that function is away from +the spike because the other Factor Delta + + align:start position:0% +the spike because the other Factor Delta + + + align:start position:0% +the spike because the other Factor Delta +is zero everything is at that Spike all + + align:start position:0% +is zero everything is at that Spike all + + + align:start position:0% +is zero everything is at that Spike all +the action and this happens to be one at + + align:start position:0% +the action and this happens to be one at + + + align:start position:0% +the action and this happens to be one at +the spike so I get a one over + + align:start position:0% +the spike so I get a one over + + + align:start position:0% +the spike so I get a one over +pi and actually the same formula for all + + align:start position:0% +pi and actually the same formula for all + + + align:start position:0% +pi and actually the same formula for all +these guys this will be the same with + + align:start position:0% +these guys this will be the same with + + + align:start position:0% +these guys this will be the same with +cos x change to cos + + align:start position:0% +cos x change to cos + + + align:start position:0% +cos x change to cos +2X and what will be the answer + + align:start position:0% +2X and what will be the answer + + + align:start position:0% +2X and what will be the answer +now again one right it's the value this + + align:start position:0% +now again one right it's the value this + + + align:start position:0% +now again one right it's the value this +integral the formula for H 2 would have + + align:start position:0% +integral the formula for H 2 would have + + + align:start position:0% +integral the formula for H 2 would have +come by multiplying both sides by cos 2x + + align:start position:0% +come by multiplying both sides by cos 2x + + + align:start position:0% +come by multiplying both sides by cos 2x +integrating uh uh and the integral of + + align:start position:0% +integrating uh uh and the integral of + + + align:start position:0% +integrating uh uh and the integral of +cos squar would give me the pi and I'm + + align:start position:0% +cos squar would give me the pi and I'm + + + align:start position:0% +cos squar would give me the pi and I'm +dividing by the pi and I just need that + + align:start position:0% +dividing by the pi and I just need that + + + align:start position:0% +dividing by the pi and I just need that +integral and it's easy it's also one + + align:start position:0% +integral and it's easy it's also one + + + align:start position:0% +integral and it's easy it's also one +over Pi so all these are one over Pi let + + align:start position:0% +over Pi so all these are one over Pi let + + + align:start position:0% +over Pi so all these are one over Pi let +me just put in the Formula 1 over 2 pi + + align:start position:0% +me just put in the Formula 1 over 2 pi + + + align:start position:0% +me just put in the Formula 1 over 2 pi +and all the rest are one over + + align:start position:0% + + + + align:start position:0% + +pi + + align:start position:0% +pi + + + align:start position:0% +pi +cos 3x there're all the cosiness are + + align:start position:0% +cos 3x there're all the cosiness are + + + align:start position:0% +cos 3x there're all the cosiness are +there all in the same + + align:start position:0% +there all in the same + + + align:start position:0% +there all in the same +amount uh and the constant term is uh uh + + align:start position:0% +amount uh and the constant term is uh uh + + + align:start position:0% +amount uh and the constant term is uh uh +slightly + + align:start position:0% +slightly + + + align:start position:0% +slightly +different okay that's + + align:start position:0% +different okay that's + + + align:start position:0% +different okay that's +the that's the formal fora series for + + align:start position:0% +the that's the formal fora series for + + + align:start position:0% +the that's the formal fora series for +the Delta function formal meaning you + + align:start position:0% +the Delta function formal meaning you + + + align:start position:0% +the Delta function formal meaning you +can use it to to uh compute uh of course + + align:start position:0% +can use it to to uh compute uh of course + + + align:start position:0% +can use it to to uh compute uh of course +some things will fail like what's the + + align:start position:0% +some things will fail like what's the + + + align:start position:0% +some things will fail like what's the +energy what's if I integrate if I try to + + align:start position:0% +energy what's if I integrate if I try to + + + align:start position:0% +energy what's if I integrate if I try to +do energy in X space of the Delta + + align:start position:0% +do energy in X space of the Delta + + + align:start position:0% +do energy in X space of the Delta +function or energy in k space what + + align:start position:0% +function or energy in k space what + + + align:start position:0% +function or energy in k space what +answer would I get well the right the + + align:start position:0% +answer would I get well the right the + + + align:start position:0% +answer would I get well the right the +integral of Delta squared its energy is + + align:start position:0% +integral of Delta squared its energy is + + + align:start position:0% +integral of Delta squared its energy is +infinite right the integral of Delta if + + align:start position:0% +infinite right the integral of Delta if + + + align:start position:0% +infinite right the integral of Delta if +I have Delta times Delta then I'm really + + align:start position:0% +I have Delta times Delta then I'm really + + + align:start position:0% +I have Delta times Delta then I'm really +in trouble right because because this + + align:start position:0% +in trouble right because because this + + + align:start position:0% +in trouble right because because this +Delta says if I can speak informally + + align:start position:0% +Delta says if I can speak informally + + + align:start position:0% +Delta says if I can speak informally +that Delta says take the value of this + + align:start position:0% +that Delta says take the value of this + + + align:start position:0% +that Delta says take the value of this +function at zero but of course that's + + align:start position:0% +function at zero but of course that's + + + align:start position:0% +function at zero but of course that's +infinite so so that would be infinite + + align:start position:0% +infinite so so that would be infinite + + + align:start position:0% +infinite so so that would be infinite +that would be that would be the energy + + align:start position:0% +that would be that would be the energy + + + align:start position:0% +that would be that would be the energy +in the in X space what about the energy + + align:start position:0% +in the in X space what about the energy + + + align:start position:0% +in the in X space what about the energy +in KS space well I + + align:start position:0% +in KS space well I + + + align:start position:0% +in KS space well I +haven't let's think what is what's the + + align:start position:0% +haven't let's think what is what's the + + + align:start position:0% +haven't let's think what is what's the +energy in k space I'm going to do the + + align:start position:0% +energy in k space I'm going to do the + + + align:start position:0% +energy in k space I'm going to do the +squares of the coefficients you remember + + align:start position:0% +squares of the coefficients you remember + + + align:start position:0% +squares of the coefficients you remember +that's what I had down + + align:start position:0% +that's what I had down + + + align:start position:0% +that's what I had down +here and I'll have it again in a moment + + align:start position:0% +here and I'll have it again in a moment + + + align:start position:0% +here and I'll have it again in a moment +it's the sum of the squares of the + + align:start position:0% +it's the sum of the squares of the + + + align:start position:0% +it's the sum of the squares of the +coefficients fixed up by factors of Pi + + align:start position:0% +coefficients fixed up by factors of Pi + + + align:start position:0% +coefficients fixed up by factors of Pi +uh and here all the coefficients are + + align:start position:0% +uh and here all the coefficients are + + + align:start position:0% +uh and here all the coefficients are +constant so that sum is infinite again + + align:start position:0% +constant so that sum is infinite again + + + align:start position:0% +constant so that sum is infinite again +it's the sum of squares of constant + + align:start position:0% +it's the sum of squares of constant + + + align:start position:0% +it's the sum of squares of constant +constant constant constant and that + + align:start position:0% +constant constant constant and that + + + align:start position:0% +constant constant constant and that +series doesn't converge it blows up so + + align:start position:0% +series doesn't converge it blows up so + + + align:start position:0% +series doesn't converge it blows up so +the energy is infinite that's that's + + align:start position:0% +the energy is infinite that's that's + + + align:start position:0% +the energy is infinite that's that's +okay the the key is that formula okay + + align:start position:0% +okay the the key is that formula okay + + + align:start position:0% +okay the the key is that formula okay +there's there's the formula to remember + + align:start position:0% +there's there's the formula to remember + + + align:start position:0% +there's there's the formula to remember +there's the formula on forever every + + align:start position:0% +there's the formula on forever every + + + align:start position:0% +there's the formula on forever every +frequency is in here uh to the to the + + align:start position:0% +frequency is in here uh to the to the + + + align:start position:0% +frequency is in here uh to the to the +same + + align:start position:0% +same + + + align:start position:0% +same +amount yeah okay good that that's that's + + align:start position:0% +amount yeah okay good that that's that's + + + align:start position:0% +amount yeah okay good that that's that's +the Delta function example okay ready to + + align:start position:0% +the Delta function example okay ready to + + + align:start position:0% +the Delta function example okay ready to +go to + + align:start position:0% + + + + align:start position:0% + +complex yeah comp complex is no big deal + + align:start position:0% +complex yeah comp complex is no big deal + + + align:start position:0% +complex yeah comp complex is no big deal +because we know actually you can tell me + + align:start position:0% +because we know actually you can tell me + + + align:start position:0% +because we know actually you can tell me +the the the complex series for the Delta + + align:start position:0% +the the the complex series for the Delta + + + align:start position:0% +the the the complex series for the Delta +function I'll write it right underneath + + align:start position:0% +function I'll write it right underneath + + + align:start position:0% +function I'll write it right underneath +the complex series for the Delta + + align:start position:0% +the complex series for the Delta + + + align:start position:0% +the complex series for the Delta +function just turn these guys + + align:start position:0% +function just turn these guys + + + align:start position:0% +function just turn these guys +into e to the I Theta e to the I x's and + + align:start position:0% +into e to the I Theta e to the I x's and + + + align:start position:0% +into e to the I Theta e to the I x's and +e to the i 2 X's and e to the i e to the + + align:start position:0% +e to the i 2 X's and e to the i e to the + + + align:start position:0% +e to the i 2 X's and e to the i e to the +minus I 2x's just term by term just to + + align:start position:0% +minus I 2x's just term by term just to + + + align:start position:0% +minus I 2x's just term by term just to +see it you know see it clearly for this + + align:start position:0% +see it you know see it clearly for this + + + align:start position:0% +see it you know see it clearly for this +great example so what do what does + + align:start position:0% +great example so what do what does + + + align:start position:0% +great example so what do what does +cosine 2X look like in term terms of uh + + align:start position:0% +cosine 2X look like in term terms of uh + + + align:start position:0% +cosine 2X look like in term terms of uh +complex + + align:start position:0% +complex + + + align:start position:0% +complex +exponentials everybody knows cost Cost + + align:start position:0% +exponentials everybody knows cost Cost + + + align:start position:0% +exponentials everybody knows cost Cost +cos x is the same + + align:start position:0% +cos x is the same + + + align:start position:0% +cos x is the same +as e to the + + align:start position:0% +as e to the + + + align:start position:0% +as e to the +iix and e to the minus IX right divided + + align:start position:0% +iix and e to the minus IX right divided + + + align:start position:0% +iix and e to the minus IX right divided +by two because this is cos x plus I sinx + + align:start position:0% +by two because this is cos x plus I sinx + + + align:start position:0% +by two because this is cos x plus I sinx +this is cos x minus I sinx when I add + + align:start position:0% +this is cos x minus I sinx when I add + + + align:start position:0% +this is cos x minus I sinx when I add +them I get two cosine X's so I must + + align:start position:0% +them I get two cosine X's so I must + + + align:start position:0% +them I get two cosine X's so I must +divide by two let me divide by two all + + align:start position:0% +divide by two let me divide by two all + + + align:start position:0% +divide by two let me divide by two all +the way so so I'm dividing this one over + + align:start position:0% +the way so so I'm dividing this one over + + + align:start position:0% +the way so so I'm dividing this one over +Pi by two you you'll see it's so much + + align:start position:0% +Pi by two you you'll see it's so much + + + align:start position:0% +Pi by two you you'll see it's so much +nicer so one over 2 pi * the one that's + + align:start position:0% +nicer so one over 2 pi * the one that's + + + align:start position:0% +nicer so one over 2 pi * the one that's +our first guy and now I've got the next + + align:start position:0% +our first guy and now I've got the next + + + align:start position:0% +our first guy and now I've got the next +guy right because I need to divide by + + align:start position:0% +guy right because I need to divide by + + + align:start position:0% +guy right because I need to divide by +the two to get the cosine and there's my + + align:start position:0% +the two to get the cosine and there's my + + + align:start position:0% +the two to get the cosine and there's my +two okay what's the next what do I have + + align:start position:0% +two okay what's the next what do I have + + + align:start position:0% +two okay what's the next what do I have +next from this guy one over pi + + align:start position:0% +next from this guy one over pi + + + align:start position:0% +next from this guy one over pi +still there what's cosine of 2x if I if + + align:start position:0% +still there what's cosine of 2x if I if + + + align:start position:0% +still there what's cosine of 2x if I if +I want to write it in terms of complex + + align:start position:0% +I want to write it in terms of complex + + + align:start position:0% +I want to write it in terms of complex +exponentials so this guy now I'm ready + + align:start position:0% +exponentials so this guy now I'm ready + + + align:start position:0% +exponentials so this guy now I'm ready +for him + + align:start position:0% + + + + align:start position:0% + +is e to the + + align:start position:0% + + + + align:start position:0% + +i2x + + align:start position:0% +i2x + + + align:start position:0% +i2x +and e to the minus + + align:start position:0% +and e to the minus + + + align:start position:0% +and e to the minus +i2x divided by two and there's my two do + + align:start position:0% +i2x divided by two and there's my two do + + + align:start position:0% +i2x divided by two and there's my two do +you see what's happening it's like + + align:start position:0% +you see what's happening it's like + + + align:start position:0% +you see what's happening it's like +there's an example to show you why the + + align:start position:0% +there's an example to show you why the + + + align:start position:0% +there's an example to show you why the +complex case is so nice here we had to + + align:start position:0% +complex case is so nice here we had to + + + align:start position:0% +complex case is so nice here we had to +remember uh a different number for the + + align:start position:0% +remember uh a different number for the + + + align:start position:0% +remember uh a different number for the +for a not here it it it's just so the + + align:start position:0% +for a not here it it it's just so the + + + align:start position:0% +for a not here it it it's just so the +next one will be e to the i3x and e to + + align:start position:0% +next one will be e to the i3x and e to + + + align:start position:0% +next one will be e to the i3x and e to +the minus i3x so the the the the Delta + + align:start position:0% +the minus i3x so the the the the Delta + + + align:start position:0% +the minus i3x so the the the the Delta +function in the complex 4 a series all + + align:start position:0% +function in the complex 4 a series all + + + align:start position:0% +function in the complex 4 a series all +the terms have coefficients one divided + + align:start position:0% +the terms have coefficients one divided + + + align:start position:0% +the terms have coefficients one divided +the two Pi that's a great example great + + align:start position:0% +the two Pi that's a great example great + + + align:start position:0% +the two Pi that's a great example great +example yeah and of course we see again + + align:start position:0% +example yeah and of course we see again + + + align:start position:0% +example yeah and of course we see again +that uh the sum of squares oh yeah so + + align:start position:0% +that uh the sum of squares oh yeah so + + + align:start position:0% +that uh the sum of squares oh yeah so +let's get to the let's do the complex + + align:start position:0% +let's get to the let's do the complex + + + align:start position:0% +let's get to the let's do the complex +formula uh the complex formula by which + + align:start position:0% +formula uh the complex formula by which + + + align:start position:0% +formula uh the complex formula by which +I mean I'm taking any function + + align:start position:0% +I mean I'm taking any function + + + align:start position:0% +I mean I'm taking any function +f not + + align:start position:0% +f not + + + align:start position:0% +f not +necessarily even not necessarily odd not + + align:start position:0% +necessarily even not necessarily odd not + + + align:start position:0% +necessarily even not necessarily odd not +necessarily real any function it can now + + align:start position:0% +necessarily real any function it can now + + + align:start position:0% +necessarily real any function it can now +be a complex function because we're + + align:start position:0% +be a complex function because we're + + + align:start position:0% +be a complex function because we're +going to use complex things here so I'll + + align:start position:0% +going to use complex things here so I'll + + + align:start position:0% +going to use complex things here so I'll +have all + + align:start position:0% + + + + align:start position:0% + +the complex exponentials for integer K + + align:start position:0% +the complex exponentials for integer K + + + align:start position:0% +the complex exponentials for integer K +this K is an integer but it can go + + align:start position:0% +this K is an integer but it can go + + + align:start position:0% +this K is an integer but it can go +from minus infinity to + + align:start position:0% +from minus infinity to + + + align:start position:0% +from minus infinity to +Infinity that's that's the complex form + + align:start position:0% +Infinity that's that's the complex form + + + align:start position:0% +Infinity that's that's the complex form +f ofx is the + + align:start position:0% +f ofx is the + + + align:start position:0% +f ofx is the +the the uh is a is a series again the + + align:start position:0% +the the uh is a is a series again the + + + align:start position:0% +the the uh is a is a series again the +beauty is that every term looks the + + align:start position:0% +beauty is that every term looks the + + + align:start position:0% +beauty is that every term looks the +same the thing you have to remember is + + align:start position:0% +same the thing you have to remember is + + + align:start position:0% +same the thing you have to remember is +that K negative K is allowed as well as + + align:start position:0% +that K negative K is allowed as well as + + + align:start position:0% +that K negative K is allowed as well as +positive K you see that we need we + + align:start position:0% +positive K you see that we need we + + + align:start position:0% +positive K you see that we need we +needed the negative K to get + + align:start position:0% +needed the negative K to get + + + align:start position:0% +needed the negative K to get +cosiness K was minus one there K was + + align:start position:0% +cosiness K was minus one there K was + + + align:start position:0% +cosiness K was minus one there K was +minus two there and for signs we would + + align:start position:0% +minus two there and for signs we would + + + align:start position:0% +minus two there and for signs we would +also need them so so cosiness go into it + + align:start position:0% +also need them so so cosiness go into it + + + align:start position:0% +also need them so so cosiness go into it +signs go into it f ofx could be complex + + align:start position:0% +signs go into it f ofx could be complex + + + align:start position:0% +signs go into it f ofx could be complex +that's the complex Series so maybe we + + align:start position:0% +that's the complex Series so maybe we + + + align:start position:0% +that's the complex Series so maybe we +should we could have started with that + + align:start position:0% +should we could have started with that + + + align:start position:0% +should we could have started with that +series but but we didn't we came to it + + align:start position:0% +series but but we didn't we came to it + + + align:start position:0% +series but but we didn't we came to it +here but let's what's the formula for + + align:start position:0% +here but let's what's the formula for + + + align:start position:0% +here but let's what's the formula for +its + + align:start position:0% +its + + + align:start position:0% +its +coefficients okay + + align:start position:0% +coefficients okay + + + align:start position:0% +coefficients okay +actually for the next half hour now we + + align:start position:0% +actually for the next half hour now we + + + align:start position:0% +actually for the next half hour now we +have to think complex and that will + + align:start position:0% +have to think complex and that will + + + align:start position:0% +have to think complex and that will +bring a few changes so watch for the + + align:start position:0% +bring a few changes so watch for the + + + align:start position:0% +bring a few changes so watch for the +changes you you see that it's we're + + align:start position:0% +changes you you see that it's we're + + + align:start position:0% +changes you you see that it's we're +almost in in the same + + align:start position:0% +almost in in the same + + + align:start position:0% +almost in in the same +uh ballp part but there are a couple of + + align:start position:0% +uh ballp part but there are a couple of + + + align:start position:0% +uh ballp part but there are a couple of +things to notice so let me write down + + align:start position:0% +things to notice so let me write down + + + align:start position:0% +things to notice so let me write down +that series again minus infinity to + + align:start position:0% +that series again minus infinity to + + + align:start position:0% +that series again minus infinity to +Infinity of some coefficient e to the I + + align:start position:0% +Infinity of some coefficient e to the I + + + align:start position:0% +Infinity of some coefficient e to the I +KX now what is + + align:start position:0% +KX now what is + + + align:start position:0% +KX now what is +CK what is the + + align:start position:0% + + + + align:start position:0% + +formula for + + align:start position:0% +formula for + + + align:start position:0% +formula for +CK as soon as we answer that question + + align:start position:0% +CK as soon as we answer that question + + + align:start position:0% +CK as soon as we answer that question +you'll see the new the new aspect for + + align:start position:0% +you'll see the new the new aspect for + + + align:start position:0% +you'll see the new the new aspect for +complex how am I how do I find + + align:start position:0% +complex how am I how do I find + + + align:start position:0% +complex how am I how do I find +coefficients I multiply by something I + + align:start position:0% +coefficients I multiply by something I + + + align:start position:0% +coefficients I multiply by something I +integrate and I use orthogonality always + + align:start position:0% +integrate and I use orthogonality always + + + align:start position:0% +integrate and I use orthogonality always +same same ideas just repeat after repeat + + align:start position:0% +same same ideas just repeat after repeat + + + align:start position:0% +same same ideas just repeat after repeat +the question is what do I multiply with + + align:start position:0% +the question is what do I multiply with + + + align:start position:0% +the question is what do I multiply with +by if I wanted to know + + align:start position:0% +by if I wanted to know + + + align:start position:0% +by if I wanted to know +C3 suppose I want to know a formula for + + align:start position:0% +C3 suppose I want to know a formula for + + + align:start position:0% +C3 suppose I want to know a formula for +C3 the coefficient what am I going to + + align:start position:0% +C3 the coefficient what am I going to + + + align:start position:0% +C3 the coefficient what am I going to +multiply by I that's going to give me + + align:start position:0% +multiply by I that's going to give me + + + align:start position:0% +multiply by I that's going to give me +the orthogonality I need that all the + + align:start position:0% +the orthogonality I need that all the + + + align:start position:0% +the orthogonality I need that all the +other integrals are going to disappear + + align:start position:0% +other integrals are going to disappear + + + align:start position:0% +other integrals are going to disappear +that's the key I want to multiply by + + align:start position:0% +that's the key I want to multiply by + + + align:start position:0% +that's the key I want to multiply by +something so that when I integrate all + + align:start position:0% +something so that when I integrate all + + + align:start position:0% +something so that when I integrate all +the other integrals are going to + + align:start position:0% +the other integrals are going to + + + align:start position:0% +the other integrals are going to +disappear and let's just do it here + + align:start position:0% +disappear and let's just do it here + + + align:start position:0% +disappear and let's just do it here +suppose I have e to the + + align:start position:0% +suppose I have e to the + + + align:start position:0% +suppose I have e to the +I 5x and I would like + + align:start position:0% +I 5x and I would like + + + align:start position:0% +I 5x and I would like +that I'm looking for the the oh no sorry + + align:start position:0% +that I'm looking for the the oh no sorry + + + align:start position:0% +that I'm looking for the the oh no sorry +I'm looking for C3 so I'll look look at + + align:start position:0% +I'm looking for C3 so I'll look look at + + + align:start position:0% +I'm looking for C3 so I'll look look at +e to the by + + align:start position:0% + + + + align:start position:0% + +3x so so + + align:start position:0% +3x so so + + + align:start position:0% +3x so so +watch this is the small point we have to + + align:start position:0% +watch this is the small point we have to + + + align:start position:0% +watch this is the small point we have to +make so so I'm looking for the E to the + + align:start position:0% +make so so I'm looking for the E to the + + + align:start position:0% +make so so I'm looking for the E to the +i3x so I'm going to multiply by + + align:start position:0% +i3x so I'm going to multiply by + + + align:start position:0% +i3x so I'm going to multiply by +something and I'm going to integrate and + + align:start position:0% +something and I'm going to integrate and + + + align:start position:0% +something and I'm going to integrate and +what would be the good thing to multiply + + align:start position:0% +what would be the good thing to multiply + + + align:start position:0% +what would be the good thing to multiply +by well you would say if you were just a + + align:start position:0% +by well you would say if you were just a + + + align:start position:0% +by well you would say if you were just a +real person you would say multiply by e + + align:start position:0% +real person you would say multiply by e + + + align:start position:0% +real person you would say multiply by e +to the i3x and integrate and hope for + + align:start position:0% +to the i3x and integrate and hope for + + + align:start position:0% +to the i3x and integrate and hope for +getting zero you won't get zero If I + + align:start position:0% +getting zero you won't get zero If I + + + align:start position:0% +getting zero you won't get zero If I +multiply e to the i3x I'm sorry you you + + align:start position:0% +multiply e to the i3x I'm sorry you you + + + align:start position:0% +multiply e to the i3x I'm sorry you you +might say m yeah what am I doing here I + + align:start position:0% +might say m yeah what am I doing here I + + + align:start position:0% +might say m yeah what am I doing here I +I I'm trying to check orthogonality let + + align:start position:0% +I I'm trying to check orthogonality let + + + align:start position:0% +I I'm trying to check orthogonality let +me let me instead of three use a a + + align:start position:0% + + + + align:start position:0% + +KX okay so that's a typical complex one + + align:start position:0% +KX okay so that's a typical complex one + + + align:start position:0% +KX okay so that's a typical complex one +it's any one of these guys and I would + + align:start position:0% +it's any one of these guys and I would + + + align:start position:0% +it's any one of these guys and I would +like to multiply it I would I would I + + align:start position:0% +like to multiply it I would I would I + + + align:start position:0% +like to multiply it I would I would I +want to see what's + + align:start position:0% +want to see what's + + + align:start position:0% +want to see what's +orthogonality that's what I'm asking + + align:start position:0% +orthogonality that's what I'm asking + + + align:start position:0% +orthogonality that's what I'm asking +everything hinged on orthogonality we've + + align:start position:0% +everything hinged on orthogonality we've + + + align:start position:0% +everything hinged on orthogonality we've +got to have orthogonality here but let + + align:start position:0% +got to have orthogonality here but let + + + align:start position:0% +got to have orthogonality here but let +me show you what it is the thing you + + align:start position:0% +me show you what it is the thing you + + + align:start position:0% +me show you what it is the thing you +multiply is by to get the C3 is not e to + + align:start position:0% +multiply is by to get the C3 is not e to + + + align:start position:0% +multiply is by to get the C3 is not e to +the i3x it is e to the minus i3x you + + align:start position:0% +the i3x it is e to the minus i3x you + + + align:start position:0% +the i3x it is e to the minus i3x you +take the conjugate you change I to minus + + align:start position:0% +take the conjugate you change I to minus + + + align:start position:0% +take the conjugate you change I to minus +I in in in in the complex cas case so if + + align:start position:0% +I in in in in the complex cas case so if + + + align:start position:0% +I in in in in the complex cas case so if +I take e to the I KX time e to the minus + + align:start position:0% +I take e to the I KX time e to the minus + + + align:start position:0% +I take e to the I KX time e to the minus +I LX and notice that minus I claim that + + align:start position:0% +I LX and notice that minus I claim that + + + align:start position:0% +I LX and notice that minus I claim that +I get + + align:start position:0% +I get + + + align:start position:0% +I get +zero except if K is L or I get and when + + align:start position:0% +zero except if K is L or I get and when + + + align:start position:0% +zero except if K is L or I get and when +K is l i get I probably I get two Pi if + + align:start position:0% +K is l i get I probably I get two Pi if + + + align:start position:0% +K is l i get I probably I get two Pi if +K is + + align:start position:0% +K is + + + align:start position:0% +K is +l i get zero if K is not L that's the + + align:start position:0% +l i get zero if K is not L that's the + + + align:start position:0% +l i get zero if K is not L that's the +that's the beautiful orthogonality I'm + + align:start position:0% +that's the beautiful orthogonality I'm + + + align:start position:0% +that's the beautiful orthogonality I'm +not too worried about the two Pi I'll + + align:start position:0% +not too worried about the two Pi I'll + + + align:start position:0% +not too worried about the two Pi I'll +figure that out it's + + align:start position:0% +figure that out it's + + + align:start position:0% +figure that out it's +the so what I'm saying is when you're + + align:start position:0% +the so what I'm saying is when you're + + + align:start position:0% +the so what I'm saying is when you're +taking inner products dot products and + + align:start position:0% +taking inner products dot products and + + + align:start position:0% +taking inner products dot products and +you've got complex stuff one of the + + align:start position:0% +you've got complex stuff one of the + + + align:start position:0% +you've got complex stuff one of the +factors has to + + align:start position:0% +factors has to + + + align:start position:0% +factors has to +get take the complex conjugate change I + + align:start position:0% +get take the complex conjugate change I + + + align:start position:0% +get take the complex conjugate change I +to minus I do do you see that we've got + + align:start position:0% +to minus I do do you see that we've got + + + align:start position:0% +to minus I do do you see that we've got +a completely easy integral now what is + + align:start position:0% +a completely easy integral now what is + + + align:start position:0% +a completely easy integral now what is +the integral of this guy how do I how do + + align:start position:0% +the integral of this guy how do I how do + + + align:start position:0% +the integral of this guy how do I how do +I see that I really get zero so this is + + align:start position:0% +I see that I really get zero so this is + + + align:start position:0% +I see that I really get zero so this is +the the first time I'm actually doing an + + align:start position:0% +the the first time I'm actually doing an + + + align:start position:0% +the the first time I'm actually doing an +integration and seeing + + align:start position:0% +integration and seeing + + + align:start position:0% +integration and seeing +orthogonality like + + align:start position:0% +orthogonality like + + + align:start position:0% +orthogonality like +anybody likes integrating these things + + align:start position:0% +anybody likes integrating these things + + + align:start position:0% +anybody likes integrating these things +because they're they're so simple to + + align:start position:0% +because they're they're so simple to + + + align:start position:0% +because they're they're so simple to +integrate what's what's the integral of + + align:start position:0% +integrate what's what's the integral of + + + align:start position:0% +integrate what's what's the integral of +if I just before I plug in the limits + + align:start position:0% +if I just before I plug in the limits + + + align:start position:0% +if I just before I plug in the limits +what's the integral of this guy how do I + + align:start position:0% +what's the integral of this guy how do I + + + align:start position:0% +what's the integral of this guy how do I +how do I rewrite that to integrate it + + align:start position:0% +how do I rewrite that to integrate it + + + align:start position:0% +how do I rewrite that to integrate it +easily I put the two exponents together + + align:start position:0% +easily I put the two exponents together + + + align:start position:0% +easily I put the two exponents together +this is the same as e to the I K minus + + align:start position:0% +this is the same as e to the I K minus + + + align:start position:0% +this is the same as e to the I K minus +LX + + align:start position:0% + + + + align:start position:0% + +right exponentials follow that rule If I + + align:start position:0% +right exponentials follow that rule If I + + + align:start position:0% +right exponentials follow that rule If I +multiply exponentials I combine the + + align:start position:0% +multiply exponentials I combine the + + + align:start position:0% +multiply exponentials I combine the +exponents and now I'm ready to integrate + + align:start position:0% +exponents and now I'm ready to integrate + + + align:start position:0% +exponents and now I'm ready to integrate +and so what is the integral of e to the + + align:start position:0% +and so what is the integral of e to the + + + align:start position:0% +and so what is the integral of e to the +i k minus + + align:start position:0% +i k minus + + + align:start position:0% +i k minus +LX when I integrate e to the i e to the + + align:start position:0% +LX when I integrate e to the i e to the + + + align:start position:0% +LX when I integrate e to the i e to the +something X I get that same thing again + + align:start position:0% +something X I get that same thing again + + + align:start position:0% +something X I get that same thing again +divided by the + + align:start position:0% +divided by the + + + align:start position:0% +divided by the +something + + align:start position:0% +something + + + align:start position:0% +something +right so now I've integrated and now I + + align:start position:0% +right so now I've integrated and now I + + + align:start position:0% +right so now I've integrated and now I +want I just want to go from 0 to 2 pi + + align:start position:0% +want I just want to go from 0 to 2 pi + + + align:start position:0% +want I just want to go from 0 to 2 pi +like in the limits from X = 0 to x = 2 + + align:start position:0% +like in the limits from X = 0 to x = 2 + + + align:start position:0% +like in the limits from X = 0 to x = 2 +pi that's this is what the integral is + + align:start position:0% +pi that's this is what the integral is + + + align:start position:0% +pi that's this is what the integral is +asking me for so I'm actually doing the + + align:start position:0% +asking me for so I'm actually doing the + + + align:start position:0% +asking me for so I'm actually doing the +integral here I'm I put these together + + align:start position:0% +integral here I'm I put these together + + + align:start position:0% +integral here I'm I put these together +into that I integrated which just + + align:start position:0% +into that I integrated which just + + + align:start position:0% +into that I integrated which just +brought this term down below because the + + align:start position:0% +brought this term down below because the + + + align:start position:0% +brought this term down below because the +derivative will bring that term above + + align:start position:0% + + + + align:start position:0% + +oh they weren't meant to change they + + align:start position:0% +oh they weren't meant to change they + + + align:start position:0% +oh they weren't meant to change they +actually it's it's wrong but right to + + align:start position:0% +actually it's it's wrong but right to + + + align:start position:0% +actually it's it's wrong but right to +change those integration limits I mean + + align:start position:0% +change those integration limits I mean + + + align:start position:0% +change those integration limits I mean +any two Pi would work but thank you it's + + align:start position:0% +any two Pi would work but thank you it's + + + align:start position:0% +any two Pi would work but thank you it's +it's you're totally right I should have + + align:start position:0% +it's you're totally right I should have + + + align:start position:0% +it's you're totally right I should have +done minus pi to + + align:start position:0% +done minus pi to + + + align:start position:0% +done minus pi to +Pi why do we get zero that's the whole + + align:start position:0% +Pi why do we get zero that's the whole + + + align:start position:0% +Pi why do we get zero that's the whole +point here we we actually did the + + align:start position:0% +point here we we actually did the + + + align:start position:0% +point here we we actually did the +integral and uh we can just plug in xal + + align:start position:0% +integral and uh we can just plug in xal + + + align:start position:0% +integral and uh we can just plug in xal +pi and xal minus Pi or we could plug in + + align:start position:0% +pi and xal minus Pi or we could plug in + + + align:start position:0% +pi and xal minus Pi or we could plug in +zero and 2 pi or I could plug in any + + align:start position:0% +zero and 2 pi or I could plug in any + + + align:start position:0% +zero and 2 pi or I could plug in any +guys that were two Pi apart any period + + align:start position:0% +guys that were two Pi apart any period + + + align:start position:0% +guys that were two Pi apart any period +of 2 pi why do we get + + align:start position:0% + + + + align:start position:0% + +zero do you have to do the plugging in + + align:start position:0% +zero do you have to do the plugging in + + + align:start position:0% +zero do you have to do the plugging in +part to see + + align:start position:0% +part to see + + + align:start position:0% +part to see +it you can certainly but the point is + + align:start position:0% +it you can certainly but the point is + + + align:start position:0% +it you can certainly but the point is +this function is + + align:start position:0% +this function is + + + align:start position:0% +this function is +periodic that's a function that has + + align:start position:0% +periodic that's a function that has + + + align:start position:0% +periodic that's a function that has +Period 2 pi so it has to be the the same + + align:start position:0% +Period 2 pi so it has to be the the same + + + align:start position:0% +Period 2 pi so it has to be the the same +at the lower and the upper limits that + + align:start position:0% +at the lower and the upper limits that + + + align:start position:0% +at the lower and the upper limits that +that's what it's coming to that's a + + align:start position:0% +that's what it's coming to that's a + + + align:start position:0% +that's what it's coming to that's a +periodic + + align:start position:0% +periodic + + + align:start position:0% +periodic +function it's equal at these two limits + + align:start position:0% +function it's equal at these two limits + + + align:start position:0% +function it's equal at these two limits +and therefore when I do the subtraction + + align:start position:0% +and therefore when I do the subtraction + + + align:start position:0% +and therefore when I do the subtraction +from you know I take it at the top limit + + align:start position:0% +from you know I take it at the top limit + + + align:start position:0% +from you know I take it at the top limit +minus the answer at the bottom limit + + align:start position:0% +minus the answer at the bottom limit + + + align:start position:0% +minus the answer at the bottom limit +it's the same at both so I get zero so + + align:start position:0% +it's the same at both so I get zero so + + + align:start position:0% +it's the same at both so I get zero so +there is the actual check of + + align:start position:0% +there is the actual check of + + + align:start position:0% +there is the actual check of +orthogonality so the the the key point + + align:start position:0% +orthogonality so the the the key point + + + align:start position:0% +orthogonality so the the the key point +was + + align:start position:0% +was + + + align:start position:0% +was +orthogonality or or in product for + + align:start position:0% +orthogonality or or in product for + + + align:start position:0% +orthogonality or or in product for +complex functions one of them has to + + align:start position:0% +complex functions one of them has to + + + align:start position:0% +complex functions one of them has to +take the complex conjugate let let me + + align:start position:0% +take the complex conjugate let let me + + + align:start position:0% +take the complex conjugate let let me +just do for vectors + + align:start position:0% +just do for vectors + + + align:start position:0% +just do for vectors +too complex + + align:start position:0% + + + + align:start position:0% + +vectors I may have mentioned let me take + + align:start position:0% +vectors I may have mentioned let me take + + + align:start position:0% +vectors I may have mentioned let me take +the vector one I as an extreme + + align:start position:0% +the vector one I as an extreme + + + align:start position:0% +the vector one I as an extreme +example and and suppose I want to define + + align:start position:0% +example and and suppose I want to define + + + align:start position:0% +example and and suppose I want to define +the inner product with + + align:start position:0% +the inner product with + + + align:start position:0% +the inner product with +itself which will be the length squared + + align:start position:0% +itself which will be the length squared + + + align:start position:0% +itself which will be the length squared +what's the inner product of that Vector + + align:start position:0% +what's the inner product of that Vector + + + align:start position:0% +what's the inner product of that Vector +that complex Vector one I with itself + + align:start position:0% +that complex Vector one I with itself + + + align:start position:0% +that complex Vector one I with itself +let me just raise it up so we see it + + align:start position:0% +let me just raise it up so we see it + + + align:start position:0% +let me just raise it up so we see it +focus on + + align:start position:0% +focus on + + + align:start position:0% +focus on +this usually the length squared would be + + align:start position:0% +this usually the length squared would be + + + align:start position:0% +this usually the length squared would be +1 2 + i + + align:start position:0% +1 2 + i + + + align:start position:0% +1 2 + i +s no good why why no + + align:start position:0% +s no good why why no + + + align:start position:0% +s no good why why no +good because it's zero 1 s plus I squ is + + align:start position:0% +good because it's zero 1 s plus I squ is + + + align:start position:0% +good because it's zero 1 s plus I squ is +zero it's just we we want we want + + align:start position:0% +zero it's just we we want we want + + + align:start position:0% +zero it's just we we want we want +absolute value + + align:start position:0% +absolute value + + + align:start position:0% +absolute value +squared absolute value + + align:start position:0% +squared absolute value + + + align:start position:0% +squared absolute value +we we need squares we need positive + + align:start position:0% +we we need squares we need positive + + + align:start position:0% +we we need squares we need positive +number here so the the length of this + + align:start position:0% +number here so the the length of this + + + align:start position:0% +number here so the the length of this +squared I would so let let me call that + + align:start position:0% +squared I would so let let me call that + + + align:start position:0% +squared I would so let let me call that +vector v i want to I want to take not V + + align:start position:0% +vector v i want to I want to take not V + + + align:start position:0% +vector v i want to I want to take not V +transpose + + align:start position:0% +transpose + + + align:start position:0% +transpose +V that's the thing that would give me + + align:start position:0% +V that's the thing that would give me + + + align:start position:0% +V that's the thing that would give me +zero if I did one + + align:start position:0% +zero if I did one + + + align:start position:0% +zero if I did one +I I have to take the complex conjugate + + align:start position:0% +I I have to take the complex conjugate + + + align:start position:0% +I I have to take the complex conjugate +one of the two factors and it's just a + + align:start position:0% +one of the two factors and it's just a + + + align:start position:0% +one of the two factors and it's just a +matter of convention which one you do + + align:start position:0% +matter of convention which one you do + + + align:start position:0% +matter of convention which one you do +this is the thing that gives me the + + align:start position:0% +this is the thing that gives me the + + + align:start position:0% +this is the thing that gives me the +length of v s and it's the same thing + + align:start position:0% +length of v s and it's the same thing + + + align:start position:0% +length of v s and it's the same thing +for functions it's the integral of f + + align:start position:0% +for functions it's the integral of f + + + align:start position:0% +for functions it's the integral of f +ofx do do you want me to write it as + + align:start position:0% +ofx do do you want me to write it as + + + align:start position:0% +ofx do do you want me to write it as +it's the integral of f ofx times its + + align:start position:0% +it's the integral of f ofx times its + + + align:start position:0% +it's the integral of f ofx times its +conjugate that gives me the length of f + + align:start position:0% +conjugate that gives me the length of f + + + align:start position:0% +conjugate that gives me the length of f +squared and of course I can rewrite that + + align:start position:0% +squared and of course I can rewrite that + + + align:start position:0% +squared and of course I can rewrite that +as the integral of f right we have the + + align:start position:0% +as the integral of f right we have the + + + align:start position:0% +as the integral of f right we have the +this handy notation for ftimes its + + align:start position:0% +this handy notation for ftimes its + + + align:start position:0% +this handy notation for ftimes its +conjugate is it's + + align:start position:0% +conjugate is it's + + + align:start position:0% +conjugate is it's +like it's like re to the I Theta time re + + align:start position:0% +like it's like re to the I Theta time re + + + align:start position:0% +like it's like re to the I Theta time re +e the minus I Theta the product of re to + + align:start position:0% +e the minus I Theta the product of re to + + + align:start position:0% +e the minus I Theta the product of re to +the I Theta + + align:start position:0% +the I Theta + + + align:start position:0% +the I Theta +time time r e the minus I Theta is + + align:start position:0% +time time r e the minus I Theta is + + + align:start position:0% +time time r e the minus I Theta is +what this is the function this is the + + align:start position:0% +what this is the function this is the + + + align:start position:0% +what this is the function this is the +complex number this is its conjugate + + align:start position:0% +complex number this is its conjugate + + + align:start position:0% +complex number this is its conjugate +when I multiply you notice that I went + + align:start position:0% +when I multiply you notice that I went + + + align:start position:0% +when I multiply you notice that I went +minus I when I drop below the imaginary + + align:start position:0% +minus I when I drop below the imaginary + + + align:start position:0% +minus I when I drop below the imaginary +axis I just the the real axis I just + + align:start position:0% +axis I just the the real axis I just + + + align:start position:0% +axis I just the the real axis I just +just change I to minus I so those cancel + + align:start position:0% +just change I to minus I so those cancel + + + align:start position:0% +just change I to minus I so those cancel +and I get R + + align:start position:0% +and I get R + + + align:start position:0% +and I get R +squ the length the size of the + + align:start position:0% +squ the length the size of the + + + align:start position:0% +squ the length the size of the +number it's just if you haven't thought + + align:start position:0% +number it's just if you haven't thought + + + align:start position:0% +number it's just if you haven't thought +complex just make this change and you're + + align:start position:0% +complex just make this change and you're + + + align:start position:0% +complex just make this change and you're +you're ready to go yeah just just V bar + + align:start position:0% +you're ready to go yeah just just V bar + + + align:start position:0% +you're ready to go yeah just just V bar +transpose V FB bar transpose F if you + + align:start position:0% +transpose V FB bar transpose F if you + + + align:start position:0% +transpose V FB bar transpose F if you +like or or f s + + align:start position:0% +like or or f s + + + align:start position:0% +like or or f s +so and when we make the correct change + + align:start position:0% +so and when we make the correct change + + + align:start position:0% +so and when we make the correct change +we have still have the + + align:start position:0% + + + + align:start position:0% + +orthogonality + + align:start position:0% +orthogonality + + + align:start position:0% +orthogonality +okay so that's what orthogonality is now + + align:start position:0% +okay so that's what orthogonality is now + + + align:start position:0% +okay so that's what orthogonality is now +what's the + + align:start position:0% +what's the + + + align:start position:0% +what's the +coefficient so now after all that speech + + align:start position:0% +coefficient so now after all that speech + + + align:start position:0% +coefficient so now after all that speech +tell me what do I multiply both sides by + + align:start position:0% +tell me what do I multiply both sides by + + + align:start position:0% +tell me what do I multiply both sides by +let me start again and and remember here + + align:start position:0% +let me start again and and remember here + + + align:start position:0% +let me start again and and remember here +so I my f ofx is going to be the sum of + + align:start position:0% +so I my f ofx is going to be the sum of + + + align:start position:0% +so I my f ofx is going to be the sum of +c k e to the I + + align:start position:0% +c k e to the I + + + align:start position:0% +c k e to the I +KX and if I want + + align:start position:0% +KX and if I want + + + align:start position:0% +KX and if I want +to get a coefficient I'm looking for a + + align:start position:0% +to get a coefficient I'm looking for a + + + align:start position:0% +to get a coefficient I'm looking for a +formula for + + align:start position:0% +formula for + + + align:start position:0% +formula for +C3 so how do I find + + align:start position:0% +C3 so how do I find + + + align:start position:0% +C3 so how do I find +C3 let's let's let me slow down a second + + align:start position:0% +C3 let's let's let me slow down a second + + + align:start position:0% +C3 let's let's let me slow down a second +how to find + + align:start position:0% + + + + align:start position:0% + +C3 + + align:start position:0% +C3 + + + align:start position:0% +C3 +multiply both sides by what and and + + align:start position:0% +multiply both sides by what and and + + + align:start position:0% +multiply both sides by what and and +integrate and integrate minus pi to Pi + + align:start position:0% +integrate and integrate minus pi to Pi + + + align:start position:0% +integrate and integrate minus pi to Pi +what goes + + align:start position:0% +what goes + + + align:start position:0% +what goes +there if I want + + align:start position:0% +there if I want + + + align:start position:0% +there if I want +C3 I should multiply both sides by + + align:start position:0% +C3 I should multiply both sides by + + + align:start position:0% +C3 I should multiply both sides by +should I multiply both sides by e to the + + align:start position:0% +should I multiply both sides by e to the + + + align:start position:0% +should I multiply both sides by e to the +i3x nope e to the minus i3x multiply + + align:start position:0% +i3x nope e to the minus i3x multiply + + + align:start position:0% +i3x nope e to the minus i3x multiply +both sides by e to the minus i3x and + + align:start position:0% +both sides by e to the minus i3x and + + + align:start position:0% +both sides by e to the minus i3x and +integrate e the minus i3x DX and then on + + align:start position:0% +integrate e the minus i3x DX and then on + + + align:start position:0% +integrate e the minus i3x DX and then on +the right side I get what I get + + align:start position:0% +the right side I get what I get + + + align:start position:0% +the right side I get what I get +C3 because that'll be either the minus + + align:start position:0% +C3 because that'll be either the minus + + + align:start position:0% +C3 because that'll be either the minus +i3x * e plus i3x that'll be I'll be + + align:start position:0% +i3x * e plus i3x that'll be I'll be + + + align:start position:0% +i3x * e plus i3x that'll be I'll be +integrating one so I'll get a 2 pi and + + align:start position:0% +integrating one so I'll get a 2 pi and + + + align:start position:0% +integrating one so I'll get a 2 pi and +all + + align:start position:0% +all + + + align:start position:0% +all +zeros from all the other + + align:start position:0% +zeros from all the other + + + align:start position:0% +zeros from all the other +terms orthogonality doing its job again + + align:start position:0% +terms orthogonality doing its job again + + + align:start position:0% +terms orthogonality doing its job again +all these zeros from or by orthogonality + + align:start position:0% +all these zeros from or by orthogonality + + + align:start position:0% +all these zeros from or by orthogonality +by + + align:start position:0% +by + + + align:start position:0% +by +orthogonality by by exactly this + + align:start position:0% +orthogonality by by exactly this + + + align:start position:0% +orthogonality by by exactly this +integration that we did if if if K is + + align:start position:0% +integration that we did if if if K is + + + align:start position:0% +integration that we did if if if K is +three and L is s or k is seven and L is + + align:start position:0% +three and L is s or k is seven and L is + + + align:start position:0% +three and L is s or k is seven and L is +three the integral gives zero so so + + align:start position:0% +three the integral gives zero so so + + + align:start position:0% +three the integral gives zero so so +what's the formula then this is all gone + + align:start position:0% +what's the formula then this is all gone + + + align:start position:0% +what's the formula then this is all gone +divide by 2 + + align:start position:0% +divide by 2 + + + align:start position:0% +divide by 2 +pi and you've got + + align:start position:0% +pi and you've got + + + align:start position:0% +pi and you've got +it there you are that's the + + align:start position:0% +it there you are that's the + + + align:start position:0% +it there you are that's the +coefficient + + align:start position:0% +coefficient + + + align:start position:0% +coefficient +okay it just we have to move to complex + + align:start position:0% +okay it just we have to move to complex + + + align:start position:0% +okay it just we have to move to complex +numbers and now in those in the those 20 + + align:start position:0% +numbers and now in those in the those 20 + + + align:start position:0% +numbers and now in those in the those 20 +minutes we've got the the only change to + + align:start position:0% +minutes we've got the the only change to + + + align:start position:0% +minutes we've got the the only change to +make is conjugate one of the one of the + + align:start position:0% +make is conjugate one of the one of the + + + align:start position:0% +make is conjugate one of the one of the +things you when when it can be complex + + align:start position:0% +things you when when it can be complex + + + align:start position:0% +things you when when it can be complex +okay good so that's the that's the + + align:start position:0% +okay good so that's the that's the + + + align:start position:0% +okay good so that's the that's the +complex series what is the uh what's the + + align:start position:0% +complex series what is the uh what's the + + + align:start position:0% +complex series what is the uh what's the +energy inequality now let me do the + + align:start position:0% +energy inequality now let me do the + + + align:start position:0% +energy inequality now let me do the +energy equality in X space and in X in k + + align:start position:0% +energy equality in X space and in X in k + + + align:start position:0% +energy equality in X space and in X in k +space if I take + + align:start position:0% +space if I take + + + align:start position:0% +space if I take +this + + align:start position:0% + + + + align:start position:0% + +now I'd like so that's an equality of + + align:start position:0% +now I'd like so that's an equality of + + + align:start position:0% +now I'd like so that's an equality of +two functions now I'd like to get + + align:start position:0% +two functions now I'd like to get + + + align:start position:0% +two functions now I'd like to get +it I I want to do + + align:start position:0% +it I I want to do + + + align:start position:0% +it I I want to do +energy this is fantastic and extremely + + align:start position:0% +energy this is fantastic and extremely + + + align:start position:0% +energy this is fantastic and extremely +practical and useful the fact that the + + align:start position:0% +practical and useful the fact that the + + + align:start position:0% +practical and useful the fact that the +energy is going to come out beautifully + + align:start position:0% +energy is going to come out beautifully + + + align:start position:0% +energy is going to come out beautifully +too so what I what am I going to do for + + align:start position:0% +too so what I what am I going to do for + + + align:start position:0% +too so what I what am I going to do for +energy I'm going to integrate f ofx + + align:start position:0% +energy I'm going to integrate f ofx + + + align:start position:0% +energy I'm going to integrate f ofx +s DX that's the + + align:start position:0% +s DX that's the + + + align:start position:0% +s DX that's the +energy that's the energy in X space in + + align:start position:0% +energy that's the energy in X space in + + + align:start position:0% +energy that's the energy in X space in +the + + align:start position:0% + + + + align:start position:0% + +function what do I do now I I I + + align:start position:0% +function what do I do now I I I + + + align:start position:0% +function what do I do now I I I +integrate this the series c k e to the I + + align:start position:0% +integrate this the series c k e to the I + + + align:start position:0% +integrate this the series c k e to the I +kx2 oh no whoa if I put a square + + align:start position:0% +kx2 oh no whoa if I put a square + + + align:start position:0% +kx2 oh no whoa if I put a square +there right I'm fired uh right what do I + + align:start position:0% +there right I'm fired uh right what do I + + + align:start position:0% +there right I'm fired uh right what do I +have to do I will put a square there but + + align:start position:0% +have to do I will put a square there but + + + align:start position:0% +have to do I will put a square there but +I have to straighten out something what + + align:start position:0% +I have to straighten out something what + + + align:start position:0% +I have to straighten out something what +do I do those curvy lines + + align:start position:0% +do I do those curvy lines + + + align:start position:0% +do I do those curvy lines +which just meant take the thing in + + align:start position:0% +which just meant take the thing in + + + align:start position:0% +which just meant take the thing in +square should be changed + + align:start position:0% + + + + align:start position:0% + +to straight just the matter of getting + + align:start position:0% +to straight just the matter of getting + + + align:start position:0% +to straight just the matter of getting +them straight straightening this out + + align:start position:0% +them straight straightening this out + + + align:start position:0% +them straight straightening this out +okay straight there we are okay now that + + align:start position:0% +okay straight there we are okay now that + + + align:start position:0% +okay straight there we are okay now that +means the thing times its conjugate + + align:start position:0% +means the thing times its conjugate + + + align:start position:0% +means the thing times its conjugate +that's the thing times its conjugate so + + align:start position:0% +that's the thing times its conjugate so + + + align:start position:0% +that's the thing times its conjugate so +what do I get all the terms disappear + + align:start position:0% +what do I get all the terms disappear + + + align:start position:0% +what do I get all the terms disappear +except the perfect the ones that are + + align:start position:0% +except the perfect the ones that are + + + align:start position:0% +except the perfect the ones that are +squared so what do I get + + align:start position:0% +squared so what do I get + + + align:start position:0% +squared so what do I get +here and the ones that are squared I'm + + align:start position:0% +here and the ones that are squared I'm + + + align:start position:0% +here and the ones that are squared I'm +integrating one so I get a 2 pi so + + align:start position:0% +integrating one so I get a 2 pi so + + + align:start position:0% +integrating one so I get a 2 pi so +there's a 2 pi the whole subject is full + + align:start position:0% +there's a 2 pi the whole subject is full + + + align:start position:0% +there's a 2 pi the whole subject is full +of these pies and two pies it's just + + align:start position:0% +of these pies and two pies it's just + + + align:start position:0% +of these pies and two pies it's just +part of the deal uh now what's + + align:start position:0% + + + + align:start position:0% + +left then now I'm looking only at the + + align:start position:0% +left then now I'm looking only at the + + + align:start position:0% +left then now I'm looking only at the +terms where I'm integrating something by + + align:start position:0% +terms where I'm integrating something by + + + align:start position:0% +terms where I'm integrating something by +its conjugate by its own conjugate and + + align:start position:0% +its conjugate by its own conjugate and + + + align:start position:0% +its conjugate by its own conjugate and +then I'm getting CK times its own + + align:start position:0% +then I'm getting CK times its own + + + align:start position:0% +then I'm getting CK times its own +conjugate so I'm getting all the terms + + align:start position:0% +conjugate so I'm getting all the terms + + + align:start position:0% +conjugate so I'm getting all the terms +I'm getting no cross terms just the + + align:start position:0% +I'm getting no cross terms just the + + + align:start position:0% +I'm getting no cross terms just the +terms that come from this from that + + align:start position:0% +terms that come from this from that + + + align:start position:0% +terms that come from this from that +times its own conjugate which is + + align:start position:0% +times its own conjugate which is + + + align:start position:0% +times its own conjugate which is +CK squar that's the energy in + + align:start position:0% +CK squar that's the energy in + + + align:start position:0% +CK squar that's the energy in +the + + align:start position:0% +the + + + align:start position:0% +the +coefficients that's the energy in k + + align:start position:0% +coefficients that's the energy in k + + + align:start position:0% +coefficients that's the energy in k +space and of course that sum goes minus + + align:start position:0% +space and of course that sum goes minus + + + align:start position:0% +space and of course that sum goes minus +infinity to Infinity I've got them all + + align:start position:0% +infinity to Infinity I've got them all + + + align:start position:0% +infinity to Infinity I've got them all +that's the energy in kpace here's the + + align:start position:0% +that's the energy in kpace here's the + + + align:start position:0% +that's the energy in kpace here's the +energy in X space yeah yeah you can + + align:start position:0% +energy in X space yeah yeah you can + + + align:start position:0% +energy in X space yeah yeah you can +expect that this uh that this + + align:start position:0% +expect that this uh that this + + + align:start position:0% +expect that this uh that this +uh orthogonality is going to give you + + align:start position:0% +uh orthogonality is going to give you + + + align:start position:0% +uh orthogonality is going to give you +something nice for uh the for the energy + + align:start position:0% +something nice for uh the for the energy + + + align:start position:0% +something nice for uh the for the energy +for this the integral of the square all + + align:start position:0% +for this the integral of the square all + + + align:start position:0% +for this the integral of the square all +right so you saw that uh and uh let's + + align:start position:0% +right so you saw that uh and uh let's + + + align:start position:0% +right so you saw that uh and uh let's +see so we saw it for we actually got a + + align:start position:0% +see so we saw it for we actually got a + + + align:start position:0% +see so we saw it for we actually got a +good number for the for the square wave + + align:start position:0% +good number for the for the square wave + + + align:start position:0% +good number for the for the square wave +we got Infinity for the Delta function + + align:start position:0% +we got Infinity for the Delta function + + + align:start position:0% +we got Infinity for the Delta function +uh I've put on here as a last uh topic + + align:start position:0% +uh I've put on here as a last uh topic + + + align:start position:0% +uh I've put on here as a last uh topic +to just give the word function tell + + align:start position:0% +to just give the word function tell + + + align:start position:0% +to just give the word function tell +you you know part of what this course is + + align:start position:0% +you you know part of what this course is + + + align:start position:0% +you you know part of what this course is +doing is to speak the language teach the + + align:start position:0% +doing is to speak the language teach the + + + align:start position:0% +doing is to speak the language teach the +language + + align:start position:0% +language + + + align:start position:0% +language +of uh of Applied + + align:start position:0% +of uh of Applied + + + align:start position:0% +of uh of Applied +math so that when you see something you + + align:start position:0% +math so that when you see something you + + + align:start position:0% +math so that when you see something you +you see this you you you recognize hey + + align:start position:0% +you see this you you you recognize hey + + + align:start position:0% +you see this you you you recognize hey +I've seen that word + + align:start position:0% +I've seen that word + + + align:start position:0% +I've seen that word +before so so I want to know what's the + + align:start position:0% +before so so I want to know what's the + + + align:start position:0% +before so so I want to know what's the +right space of functions this is my + + align:start position:0% +right space of functions this is my + + + align:start position:0% +right space of functions this is my +measure for the length squar of a + + align:start position:0% + + + + align:start position:0% + +function my Square wave is + + align:start position:0% +function my Square wave is + + + align:start position:0% +function my Square wave is +great it's its length squared was + + align:start position:0% +great it's its length squared was + + + align:start position:0% +great it's its length squared was +whatever it was pi squ over something + + align:start position:0% +whatever it was pi squ over something + + + align:start position:0% +whatever it was pi squ over something +and + + align:start position:0% +and + + + align:start position:0% +and +uh that's its that's the its length + + align:start position:0% +uh that's its that's the its length + + + align:start position:0% +uh that's its that's the its length +squared the Delta + + align:start position:0% +squared the Delta + + + align:start position:0% +squared the Delta +function would gave Infinity so I'm not + + align:start position:0% +function would gave Infinity so I'm not + + + align:start position:0% +function would gave Infinity so I'm not +it's not going to be allowed into the + + align:start position:0% +it's not going to be allowed into the + + + align:start position:0% +it's not going to be allowed into the +function space it's it's a it's a vector + + align:start position:0% +function space it's it's a it's a vector + + + align:start position:0% +function space it's it's a it's a vector +of infinite length like the vector 11111 + + align:start position:0% +of infinite length like the vector 11111 + + + align:start position:0% +of infinite length like the vector 11111 +forever too long we can't sum Pythagoras + + align:start position:0% +forever too long we can't sum Pythagoras + + + align:start position:0% +forever too long we can't sum Pythagoras +fails because we sum the squares we get + + align:start position:0% +fails because we sum the squares we get + + + align:start position:0% +fails because we sum the squares we get +infinite so what ve functions what + + align:start position:0% +infinite so what ve functions what + + + align:start position:0% +infinite so what ve functions what +vectors should we allow in our space so + + align:start position:0% +vectors should we allow in our space so + + + align:start position:0% +vectors should we allow in our space so +so we're going to have a a space it's + + align:start position:0% +so we're going to have a a space it's + + + align:start position:0% +so we're going to have a a space it's +going to be infinite dimensional because + + align:start position:0% +going to be infinite dimensional because + + + align:start position:0% +going to be infinite dimensional because +our vect our coefficients we've got + + align:start position:0% +our vect our coefficients we've got + + + align:start position:0% +our vect our coefficients we've got +infinitely many coefficients + + align:start position:0% +infinitely many coefficients + + + align:start position:0% +infinitely many coefficients +our functions have infinitely many + + align:start position:0% +our functions have infinitely many + + + align:start position:0% +our functions have infinitely many +values so we've moved up from n + + align:start position:0% +values so we've moved up from n + + + align:start position:0% +values so we've moved up from n +dimensional space to infinite + + align:start position:0% +dimensional space to infinite + + + align:start position:0% +dimensional space to infinite +dimensional space and everybody calls it + + align:start position:0% +dimensional space and everybody calls it + + + align:start position:0% +dimensional space and everybody calls it +after the guy who Hilbert + + align:start position:0% +after the guy who Hilbert + + + align:start position:0% +after the guy who Hilbert +space so I don't know if you've seen + + align:start position:0% +space so I don't know if you've seen + + + align:start position:0% +space so I don't know if you've seen +that word before H that name before + + align:start position:0% +that word before H that name before + + + align:start position:0% +that word before H that name before +Hilbert space it's the space of + + align:start position:0% +Hilbert space it's the space of + + + align:start position:0% +Hilbert space it's the space of +functions with finite energy finite + + align:start position:0% +functions with finite energy finite + + + align:start position:0% +functions with finite energy finite +length so this fun function is in it the + + align:start position:0% +length so this fun function is in it the + + + align:start position:0% +length so this fun function is in it the +Delta function is not in + + align:start position:0% +Delta function is not in + + + align:start position:0% +Delta function is not in +it uh and uh the point is that this + + align:start position:0% +it uh and uh the point is that this + + + align:start position:0% +it uh and uh the point is that this +space of functions we've got the these + + align:start position:0% +space of functions we've got the these + + + align:start position:0% +space of functions we've got the these +these guys are a great basis for the + + align:start position:0% +these guys are a great basis for the + + + align:start position:0% +these guys are a great basis for the +space of functions the signs and + + align:start position:0% +space of functions the signs and + + + align:start position:0% +space of functions the signs and +cosiness are another basis for this + + align:start position:0% +cosiness are another basis for this + + + align:start position:0% +cosiness are another basis for this +space of functions we just have a whole + + align:start position:0% +space of functions we just have a whole + + + align:start position:0% +space of functions we just have a whole +lot of functions and all the facts of + + align:start position:0% +lot of functions and all the facts of + + + align:start position:0% +lot of functions and all the facts of +n-dimensional space like so what are + + align:start position:0% +n-dimensional space like so what are + + + align:start position:0% +n-dimensional space like so what are +what are important facts about n + + align:start position:0% +what are important facts about n + + + align:start position:0% +what are important facts about n +dimensional space one that comes to mind + + align:start position:0% +dimensional space one that comes to mind + + + align:start position:0% +dimensional space one that comes to mind +is the that that's that involves length + + align:start position:0% +is the that that's that involves length + + + align:start position:0% +is the that that's that involves length +is + + align:start position:0% +is + + + align:start position:0% +is +the a key fact about length + + align:start position:0% +the a key fact about length + + + align:start position:0% +the a key fact about length +is length and + + align:start position:0% +is length and + + + align:start position:0% +is length and +angle the key the the gra I could say + + align:start position:0% +angle the key the the gra I could say + + + align:start position:0% +angle the key the the gra I could say +actually this is many people would say + + align:start position:0% +actually this is many people would say + + + align:start position:0% +actually this is many people would say +this is the most important inequality in + + align:start position:0% +this is the most important inequality in + + + align:start position:0% +this is the most important inequality in +mathematics that the dotproduct of two + + align:start position:0% +mathematics that the dotproduct of two + + + align:start position:0% +mathematics that the dotproduct of two +vectors + + align:start position:0% + + + + align:start position:0% + +do you know + + align:start position:0% + + + + align:start position:0% + +what do you know what this this it's + + align:start position:0% +what do you know what this this it's + + + align:start position:0% +what do you know what this this it's +called the Schwarz + + align:start position:0% +called the Schwarz + + + align:start position:0% +called the Schwarz +inequality several people uh found it + + align:start position:0% +inequality several people uh found it + + + align:start position:0% +inequality several people uh found it +independantly Schwarz had had uh is is + + align:start position:0% +independantly Schwarz had had uh is is + + + align:start position:0% +independantly Schwarz had had uh is is +is the single name most often + + align:start position:0% +is the single name most often + + + align:start position:0% +is the single name most often +used what do you know about the + + align:start position:0% +used what do you know about the + + + align:start position:0% +used what do you know about the +dotproduct of two + + align:start position:0% +dotproduct of two + + + align:start position:0% +dotproduct of two +vectors somehow it tells you the angle + + align:start position:0% +vectors somehow it tells you the angle + + + align:start position:0% +vectors somehow it tells you the angle +between them right somehow the the dot + + align:start position:0% +between them right somehow the the dot + + + align:start position:0% +between them right somehow the the dot +product of two + + align:start position:0% +product of two + + + align:start position:0% +product of two +vectors is if I divide by the length of + + align:start position:0% +vectors is if I divide by the length of + + + align:start position:0% +vectors is if I divide by the length of +the vectors so the dotproduct of vectors + + align:start position:0% +the vectors so the dotproduct of vectors + + + align:start position:0% +the vectors so the dotproduct of vectors +divided by the length do you know what + + align:start position:0% +divided by the length do you know what + + + align:start position:0% +divided by the length do you know what +this is in in + + align:start position:0% +this is in in + + + align:start position:0% +this is in in +Geometry it's a coine it's the coine of + + align:start position:0% +Geometry it's a coine it's the coine of + + + align:start position:0% +Geometry it's a coine it's the coine of +the angle between + + align:start position:0% +the angle between + + + align:start position:0% +the angle between +them and cosiness are never larger than + + align:start position:0% +them and cosiness are never larger than + + + align:start position:0% +them and cosiness are never larger than +one so this quantity here is never + + align:start position:0% +one so this quantity here is never + + + align:start position:0% +one so this quantity here is never +larger than one in other words this is + + align:start position:0% +larger than one in other words this is + + + align:start position:0% +larger than one in other words this is +never larger than the length of one + + align:start position:0% +never larger than the length of one + + + align:start position:0% +never larger than the length of one +vector times the length of the other + + align:start position:0% +vector times the length of the other + + + align:start position:0% +vector times the length of the other +Vector right I could do an example let V + + align:start position:0% +Vector right I could do an example let V + + + align:start position:0% +Vector right I could do an example let V +be uh + + align:start position:0% +be uh + + + align:start position:0% +be uh +13 and let + + align:start position:0% +13 and let + + + align:start position:0% +13 and let +WB six I don't know how this is going to + + align:start position:0% +WB six I don't know how this is going to + + + align:start position:0% +WB six I don't know how this is going to +work what's the dotproduct of those two + + align:start position:0% +work what's the dotproduct of those two + + + align:start position:0% +work what's the dotproduct of those two +vectors oh it's 19 sorry about that + + align:start position:0% +vectors oh it's 19 sorry about that + + + align:start position:0% +vectors oh it's 19 sorry about that +let's change this to + + align:start position:0% + + + + align:start position:0% + +what I want I'd like a nice number here + + align:start position:0% +what I want I'd like a nice number here + + + align:start position:0% +what I want I'd like a nice number here +what do you + + align:start position:0% + + + + align:start position:0% + +suggest make a five somewhere here oh + + align:start position:0% +suggest make a five somewhere here oh + + + align:start position:0% +suggest make a five somewhere here oh +yeah five wouldn't be bad five wouldn't + + align:start position:0% +yeah five wouldn't be bad five wouldn't + + + align:start position:0% +yeah five wouldn't be bad five wouldn't +be bad well it wouldn't be too good + + align:start position:0% +be bad well it wouldn't be too good + + + align:start position:0% +be bad well it wouldn't be too good +either but + + align:start position:0% + + + + align:start position:0% + +um yeah ah let's do it okay what's the + + align:start position:0% +um yeah ah let's do it okay what's the + + + align:start position:0% +um yeah ah let's do it okay what's the +dot product of those 16 and now what am + + align:start position:0% +dot product of those 16 and now what am + + + align:start position:0% +dot product of those 16 and now what am +I claiming that that's length less than + + align:start position:0% +I claiming that that's length less than + + + align:start position:0% +I claiming that that's length less than +the length of this Vector which is what + + align:start position:0% +the length of this Vector which is what + + + align:start position:0% +the length of this Vector which is what +what's the length of + + align:start position:0% +what's the length of + + + align:start position:0% +what's the length of +13 square otk of 10 it's good to do + + align:start position:0% +13 square otk of 10 it's good to do + + + align:start position:0% +13 square otk of 10 it's good to do +these small ones just to remember the + + align:start position:0% +these small ones just to remember the + + + align:start position:0% +these small ones just to remember the +length of that Vector is the sum of + + align:start position:0% +length of that Vector is the sum of + + + align:start position:0% +length of that Vector is the sum of +square root of the sum of the square + + align:start position:0% +square root of the sum of the square + + + align:start position:0% +square root of the sum of the square +square root of 10 and the length of this + + align:start position:0% +square root of 10 and the length of this + + + align:start position:0% +square root of 10 and the length of this +guy is the square root of + + align:start position:0% +guy is the square root of + + + align:start position:0% +guy is the square root of +26 and so I hope and Schwarz hopes that + + align:start position:0% +26 and so I hope and Schwarz hopes that + + + align:start position:0% +26 and so I hope and Schwarz hopes that +16 is less than that square root can we + + align:start position:0% +16 is less than that square root can we + + + align:start position:0% +16 is less than that square root can we +check it um well let's Square both sides + + align:start position:0% +check it um well let's Square both sides + + + align:start position:0% +check it um well let's Square both sides +that would make it easier uh so the + + align:start position:0% +that would make it easier uh so the + + + align:start position:0% +that would make it easier uh so the +right hand side when I Square both sides + + align:start position:0% +right hand side when I Square both sides + + + align:start position:0% +right hand side when I Square both sides +will + + align:start position:0% +will + + + align:start position:0% +will +be + + align:start position:0% +be + + + align:start position:0% +be +260 when I Square both sides and what's + + align:start position:0% +260 when I Square both sides and what's + + + align:start position:0% +260 when I Square both sides and what's +the square of + + align:start position:0% +the square of + + + align:start position:0% +the square of + + align:start position:0% + + + align:start position:0% +256 that was + + align:start position:0% +256 that was + + + align:start position:0% +256 that was +close + + align:start position:0% +close + + + align:start position:0% +close +but it worked right + + align:start position:0% +but it worked right + + + align:start position:0% +but it worked right +right I'll admit to you my whoops not + + align:start position:0% +right I'll admit to you my whoops not + + + align:start position:0% +right I'll admit to you my whoops not +equal + + align:start position:0% +equal + + + align:start position:0% +equal +ah less or equal Schwarz would say and + + align:start position:0% +ah less or equal Schwarz would say and + + + align:start position:0% +ah less or equal Schwarz would say and +uh and uh it's actually less than + + align:start position:0% +uh and uh it's actually less than + + + align:start position:0% +uh and uh it's actually less than +because these vectors are not in the + + align:start position:0% +because these vectors are not in the + + + align:start position:0% +because these vectors are not in the +same direction if they were exactly in + + align:start position:0% +same direction if they were exactly in + + + align:start position:0% +same direction if they were exactly in +the same direction or opposite + + align:start position:0% +the same direction or opposite + + + align:start position:0% +the same direction or opposite +directions the cosine would be one and + + align:start position:0% +directions the cosine would be one and + + + align:start position:0% +directions the cosine would be one and +we would have equals but since the angle + + align:start position:0% +we would have equals but since the angle + + + align:start position:0% +we would have equals but since the angle +you see the angle between those two + + align:start position:0% +you see the angle between those two + + + align:start position:0% +you see the angle between those two +vectors is is is uh you know it's it's + + align:start position:0% +vectors is is is uh you know it's it's + + + align:start position:0% +vectors is is is uh you know it's it's +pretty small angle the cosine is quite + + align:start position:0% +pretty small angle the cosine is quite + + + align:start position:0% +pretty small angle the cosine is quite +near one but it's not exactly one yeah + + align:start position:0% +near one but it's not exactly one yeah + + + align:start position:0% +near one but it's not exactly one yeah +yeah so I'm glad somebody knew 16 + + align:start position:0% +yeah so I'm glad somebody knew 16 + + + align:start position:0% +yeah so I'm glad somebody knew 16 +squared does anybody know 99 + + align:start position:0% +squared does anybody know 99 + + + align:start position:0% +squared does anybody know 99 +squared it was I the reason I asked that + + align:start position:0% +squared it was I the reason I asked that + + + align:start position:0% +squared it was I the reason I asked that +is or 999 I'll make it sound harder uh + + align:start position:0% +is or 999 I'll make it sound harder uh + + + align:start position:0% +is or 999 I'll make it sound harder uh +the was the hope when I was a about 11 + + align:start position:0% +the was the hope when I was a about 11 + + + align:start position:0% +the was the hope when I was a about 11 +or something I was always hoping + + align:start position:0% +or something I was always hoping + + + align:start position:0% +or something I was always hoping +somebody would ask me 999 squared + + align:start position:0% +somebody would ask me 999 squared + + + align:start position:0% +somebody would ask me 999 squared +because I was already ready with the + + align:start position:0% +because I was already ready with the + + + align:start position:0% +because I was already ready with the +answer nobody ever asked anyway but vast + + align:start position:0% +answer nobody ever asked anyway but vast + + + align:start position:0% +answer nobody ever asked anyway but vast +I think uh so 998,199 + + align:start position:0% + + + + align:start position:0% + +[Applause] \ No newline at end of file diff --git a/AYisLr9e0y4.txt b/AYisLr9e0y4.txt new file mode 100644 index 0000000000000000000000000000000000000000..9a32a3b570821946d7642a57e05fcd4bbe438b08 --- /dev/null +++ b/AYisLr9e0y4.txt @@ -0,0 +1,1307 @@ +align:start position:0% + +welcome back to recitation what I'd like + + align:start position:0% +welcome back to recitation what I'd like + + + align:start position:0% +welcome back to recitation what I'd like +us to do in this in these two problems + + align:start position:0% +us to do in this in these two problems + + + align:start position:0% +us to do in this in these two problems +is to understand how to compute the flux + + align:start position:0% +is to understand how to compute the flux + + + align:start position:0% +is to understand how to compute the flux +in three dimensions the flux of a vector + + align:start position:0% +in three dimensions the flux of a vector + + + align:start position:0% +in three dimensions the flux of a vector +in three dimensions across a surface + + align:start position:0% +in three dimensions across a surface + + + align:start position:0% +in three dimensions across a surface +without maybe doing a lot of calculation + + align:start position:0% +without maybe doing a lot of calculation + + + align:start position:0% +without maybe doing a lot of calculation +so we're going to see if we can figure + + align:start position:0% +so we're going to see if we can figure + + + align:start position:0% +so we're going to see if we can figure +out how to do the these problems without + + align:start position:0% +out how to do the these problems without + + + align:start position:0% +out how to do the these problems without +doing a lot of computation so the first + + align:start position:0% +doing a lot of computation so the first + + + align:start position:0% +doing a lot of computation so the first +one is to find the V sorry find the flux + + align:start position:0% +one is to find the V sorry find the flux + + + align:start position:0% +one is to find the V sorry find the flux +of the vector k through the infinite + + align:start position:0% +of the vector k through the infinite + + + align:start position:0% +of the vector k through the infinite +cylinder x^2 + y^2 equal 1 so notice + + align:start position:0% +cylinder x^2 + y^2 equal 1 so notice + + + align:start position:0% +cylinder x^2 + y^2 equal 1 so notice +this is doesn't depend on Z but in fact + + align:start position:0% +this is doesn't depend on Z but in fact + + + align:start position:0% +this is doesn't depend on Z but in fact +at every height it is it is a unit + + align:start position:0% +at every height it is it is a unit + + + align:start position:0% +at every height it is it is a unit +circle so it's an infinite cylinder and + + align:start position:0% +circle so it's an infinite cylinder and + + + align:start position:0% +circle so it's an infinite cylinder and +then the second problem I'd like you to + + align:start position:0% +then the second problem I'd like you to + + + align:start position:0% +then the second problem I'd like you to +think about and to try is to find the + + align:start position:0% +think about and to try is to find the + + + align:start position:0% +think about and to try is to find the +flux of the vector J through one square + + align:start position:0% +flux of the vector J through one square + + + align:start position:0% +flux of the vector J through one square +that has side length one in the XZ plane + + align:start position:0% +that has side length one in the XZ plane + + + align:start position:0% +that has side length one in the XZ plane +so you pick any Square in the X plane of + + align:start position:0% +so you pick any Square in the X plane of + + + align:start position:0% +so you pick any Square in the X plane of +side length one and find the flux of J + + align:start position:0% +side length one and find the flux of J + + + align:start position:0% +side length one and find the flux of J +through that square and so I think think + + align:start position:0% +through that square and so I think think + + + align:start position:0% +through that square and so I think think +that that's enough information so why + + align:start position:0% +that that's enough information so why + + + align:start position:0% +that that's enough information so why +don't you try both those problems pause + + align:start position:0% +don't you try both those problems pause + + + align:start position:0% +don't you try both those problems pause +the video and then when you're ready to + + align:start position:0% +the video and then when you're ready to + + + align:start position:0% +the video and then when you're ready to +see my explanation of of how they work + + align:start position:0% +see my explanation of of how they work + + + align:start position:0% +see my explanation of of how they work +bring the video back + + align:start position:0% + + + + align:start position:0% + +up okay welcome back again what we're + + align:start position:0% +up okay welcome back again what we're + + + align:start position:0% +up okay welcome back again what we're +trying to do is to understand the flux + + align:start position:0% +trying to do is to understand the flux + + + align:start position:0% +trying to do is to understand the flux +of a vector field across a surface and + + align:start position:0% +of a vector field across a surface and + + + align:start position:0% +of a vector field across a surface and +we're hoping to do it with the least + + align:start position:0% +we're hoping to do it with the least + + + align:start position:0% +we're hoping to do it with the least +amount of calculation possible for these + + align:start position:0% +amount of calculation possible for these + + + align:start position:0% +amount of calculation possible for these +particular problems so obviously it's + + align:start position:0% +particular problems so obviously it's + + + align:start position:0% +particular problems so obviously it's +going going to be helpful if you can + + align:start position:0% +going going to be helpful if you can + + + align:start position:0% +going going to be helpful if you can +draw a picture to draw a picture so I'm + + align:start position:0% +draw a picture to draw a picture so I'm + + + align:start position:0% +draw a picture to draw a picture so I'm +going to draw the surface that is the + + align:start position:0% +going to draw the surface that is the + + + align:start position:0% +going to draw the surface that is the +infinite cylinder first and then I'm + + align:start position:0% +infinite cylinder first and then I'm + + + align:start position:0% +infinite cylinder first and then I'm +going to look at the vector field uh K + + align:start position:0% +going to look at the vector field uh K + + + align:start position:0% +going to look at the vector field uh K +so let me draw my picture first if these + + align:start position:0% +so let me draw my picture first if these + + + align:start position:0% +so let me draw my picture first if these +are my coordinate axes I get uh I think + + align:start position:0% +are my coordinate axes I get uh I think + + + align:start position:0% +are my coordinate axes I get uh I think +you have something usually like this + + align:start position:0% +you have something usually like this + + + align:start position:0% +you have something usually like this +this is X this is y and this is z this + + align:start position:0% +this is X this is y and this is z this + + + align:start position:0% +this is X this is y and this is z this +is how you do them in your class and so + + align:start position:0% +is how you do them in your class and so + + + align:start position:0% +is how you do them in your class and so +it's not going to be a great picture but + + align:start position:0% +it's not going to be a great picture but + + + align:start position:0% +it's not going to be a great picture but +I'm going to try and make it look like a + + align:start position:0% +I'm going to try and make it look like a + + + align:start position:0% +I'm going to try and make it look like a +cylinder a + + align:start position:0% +cylinder a + + + align:start position:0% +cylinder a +here coming down so this is in fact it's + + align:start position:0% +here coming down so this is in fact it's + + + align:start position:0% +here coming down so this is in fact it's +going to be infinitely long going down + + align:start position:0% +going to be infinitely long going down + + + align:start position:0% +going to be infinitely long going down +forever but I'll stop it somewhere down + + align:start position:0% +forever but I'll stop it somewhere down + + + align:start position:0% +forever but I'll stop it somewhere down +here and then so every slice in the Z at + + align:start position:0% +here and then so every slice in the Z at + + + align:start position:0% +here and then so every slice in the Z at +a fixed height for Z is going to be a + + align:start position:0% +a fixed height for Z is going to be a + + + align:start position:0% +a fixed height for Z is going to be a +circle so that's I should think about + + align:start position:0% +circle so that's I should think about + + + align:start position:0% +circle so that's I should think about +these are intersecting the X and Y axis + + align:start position:0% +these are intersecting the X and Y axis + + + align:start position:0% +these are intersecting the X and Y axis +at 1 0 and 01 so there's actually a sort + + align:start position:0% +at 1 0 and 01 so there's actually a sort + + + align:start position:0% +at 1 0 and 01 so there's actually a sort +of unit circle down here as well now + + align:start position:0% +of unit circle down here as well now + + + align:start position:0% +of unit circle down here as well now +that's the surface + + align:start position:0% +that's the surface + + + align:start position:0% +that's the surface +now what does the vector field look like + + align:start position:0% +now what does the vector field look like + + + align:start position:0% +now what does the vector field look like +well in general what does the vector + + align:start position:0% +well in general what does the vector + + + align:start position:0% +well in general what does the vector +field look like K is just a constant + + align:start position:0% +field look like K is just a constant + + + align:start position:0% +field look like K is just a constant +Vector field that points in this + + align:start position:0% +Vector field that points in this + + + align:start position:0% +Vector field that points in this +direction this is K so k at every point + + align:start position:0% +direction this is K so k at every point + + + align:start position:0% +direction this is K so k at every point +on the surface is just the vector that's + + align:start position:0% +on the surface is just the vector that's + + + align:start position:0% +on the surface is just the vector that's +pointing straight up in this direction + + align:start position:0% +pointing straight up in this direction + + + align:start position:0% +pointing straight up in this direction +and the normal to the surface if you + + align:start position:0% +and the normal to the surface if you + + + align:start position:0% +and the normal to the surface if you +think about it the normal to the surface + + align:start position:0% +think about it the normal to the surface + + + align:start position:0% +think about it the normal to the surface +is independent of Z it doesn't depend on + + align:start position:0% +is independent of Z it doesn't depend on + + + align:start position:0% +is independent of Z it doesn't depend on +Z at all it is always going to be a + + align:start position:0% +Z at all it is always going to be a + + + align:start position:0% +Z at all it is always going to be a +vector that is in the XY Direction only + + align:start position:0% +vector that is in the XY Direction only + + + align:start position:0% +vector that is in the XY Direction only +it's going to be essentially at every + + align:start position:0% +it's going to be essentially at every + + + align:start position:0% +it's going to be essentially at every +point it's going to be be sitting in the + + align:start position:0% +point it's going to be be sitting in the + + + align:start position:0% +point it's going to be be sitting in the +the plane Z equals a constant because if + + align:start position:0% +the plane Z equals a constant because if + + + align:start position:0% +the plane Z equals a constant because if +you think about what you have you have a + + align:start position:0% +you think about what you have you have a + + + align:start position:0% +you think about what you have you have a +unit circle at every height and it + + align:start position:0% +unit circle at every height and it + + + align:start position:0% +unit circle at every height and it +doesn't vary in the Z Direction at all + + align:start position:0% +doesn't vary in the Z Direction at all + + + align:start position:0% +doesn't vary in the Z Direction at all +with that the bending of that unit + + align:start position:0% +with that the bending of that unit + + + align:start position:0% +with that the bending of that unit +circle so in fact the normal is always + + align:start position:0% +circle so in fact the normal is always + + + align:start position:0% +circle so in fact the normal is always +going to point straight out from the + + align:start position:0% +going to point straight out from the + + + align:start position:0% +going to point straight out from the +unit circle there's going to be no Z + + align:start position:0% +unit circle there's going to be no Z + + + align:start position:0% +unit circle there's going to be no Z +component or I should say the Z + + align:start position:0% +component or I should say the Z + + + align:start position:0% +component or I should say the Z +component zero maybe that's the best way + + align:start position:0% +component zero maybe that's the best way + + + align:start position:0% +component zero maybe that's the best way +to say it so that means that the normal + + align:start position:0% +to say it so that means that the normal + + + align:start position:0% +to say it so that means that the normal +dotted with K is going to be zero and so + + align:start position:0% +dotted with K is going to be zero and so + + + align:start position:0% +dotted with K is going to be zero and so +the answer to the first question is the + + align:start position:0% +the answer to the first question is the + + + align:start position:0% +the answer to the first question is the +flux of K through the infinite cylinder + + align:start position:0% +flux of K through the infinite cylinder + + + align:start position:0% +flux of K through the infinite cylinder +is actually + + align:start position:0% +is actually + + + align:start position:0% +is actually +zero okay so the answer to part + + align:start position:0% +zero okay so the answer to part + + + align:start position:0% +zero okay so the answer to part +A is zero been getting a lot of zeros in + + align:start position:0% +A is zero been getting a lot of zeros in + + + align:start position:0% +A is zero been getting a lot of zeros in +my videos so far okay the next one is + + align:start position:0% +my videos so far okay the next one is + + + align:start position:0% +my videos so far okay the next one is +Def find the flux of the vector J + + align:start position:0% +Def find the flux of the vector J + + + align:start position:0% +Def find the flux of the vector J +through one square in the XZ plane where + + align:start position:0% +through one square in the XZ plane where + + + align:start position:0% +through one square in the XZ plane where +the squares have side length one so I + + align:start position:0% +the squares have side length one so I + + + align:start position:0% +the squares have side length one so I +can draw any Square I want that seems to + + align:start position:0% +can draw any Square I want that seems to + + + align:start position:0% +can draw any Square I want that seems to +imply that maybe it'll be the same + + align:start position:0% +imply that maybe it'll be the same + + + align:start position:0% +imply that maybe it'll be the same +answer everywhere so let's see what we + + align:start position:0% +answer everywhere so let's see what we + + + align:start position:0% +answer everywhere so let's see what we +get let me draw a picture for Part B + + align:start position:0% +get let me draw a picture for Part B + + + align:start position:0% +get let me draw a picture for Part B +should label this first Maybe + + align:start position:0% +should label this first Maybe + + + align:start position:0% +should label this first Maybe +okay let me label my + + align:start position:0% + + + + align:start position:0% + +axes and I'm going to draw the simplest + + align:start position:0% +axes and I'm going to draw the simplest + + + align:start position:0% +axes and I'm going to draw the simplest +one I can that does not look like a + + align:start position:0% +one I can that does not look like a + + + align:start position:0% +one I can that does not look like a +square + + align:start position:0% +square + + + align:start position:0% +square +but I'm not great at this there we go + + align:start position:0% +but I'm not great at this there we go + + + align:start position:0% +but I'm not great at this there we go +okay so this is my Surface sitting in + + align:start position:0% +okay so this is my Surface sitting in + + + align:start position:0% +okay so this is my Surface sitting in +the XZ plane this side length is one and + + align:start position:0% +the XZ plane this side length is one and + + + align:start position:0% +the XZ plane this side length is one and +this side length is one all right so + + align:start position:0% +this side length is one all right so + + + align:start position:0% +this side length is one all right so +what is the normal to that surface well + + align:start position:0% +what is the normal to that surface well + + + align:start position:0% +what is the normal to that surface well +we have two choices and so we will + + align:start position:0% +we have two choices and so we will + + + align:start position:0% +we have two choices and so we will +actually have a possibility of two + + align:start position:0% +actually have a possibility of two + + + align:start position:0% +actually have a possibility of two +answers so let me point out that the + + align:start position:0% +answers so let me point out that the + + + align:start position:0% +answers so let me point out that the +normal to the surface well what + + align:start position:0% +normal to the surface well what + + + align:start position:0% +normal to the surface well what +direction does it point in because this + + align:start position:0% +direction does it point in because this + + + align:start position:0% +direction does it point in because this +plane is in the XZ plane the normal to + + align:start position:0% +plane is in the XZ plane the normal to + + + align:start position:0% +plane is in the XZ plane the normal to +the surface is either J or it's minus J + + align:start position:0% +the surface is either J or it's minus J + + + align:start position:0% +the surface is either J or it's minus J +right and so if I'm integrating J dotted + + align:start position:0% +right and so if I'm integrating J dotted + + + align:start position:0% +right and so if I'm integrating J dotted +with the normal over the + + align:start position:0% +with the normal over the + + + align:start position:0% +with the normal over the +surface I I'll just call this surface + + align:start position:0% +surface I I'll just call this surface + + + align:start position:0% +surface I I'll just call this surface +capital r if I'm integrating over r j + + align:start position:0% +capital r if I'm integrating over r j + + + align:start position:0% +capital r if I'm integrating over r j +dotted with the normal DS right J dotted + + align:start position:0% +dotted with the normal DS right J dotted + + + align:start position:0% +dotted with the normal DS right J dotted +with the normal is going to be either + + align:start position:0% +with the normal is going to be either + + + align:start position:0% +with the normal is going to be either +one or minus one and hopefully that + + align:start position:0% +one or minus one and hopefully that + + + align:start position:0% +one or minus one and hopefully that +makes sense because J let me draw this J + + align:start position:0% +makes sense because J let me draw this J + + + align:start position:0% +makes sense because J let me draw this J +is pointing exactly in the y direction + + align:start position:0% +is pointing exactly in the y direction + + + align:start position:0% +is pointing exactly in the y direction +right and the normal is either in this + + align:start position:0% +right and the normal is either in this + + + align:start position:0% +right and the normal is either in this +direction or in the opposite direction + + align:start position:0% +direction or in the opposite direction + + + align:start position:0% +direction or in the opposite direction +up to how I choose to orient the surface + + align:start position:0% +up to how I choose to orient the surface + + + align:start position:0% +up to how I choose to orient the surface +and so J down with n is either plus or + + align:start position:0% +and so J down with n is either plus or + + + align:start position:0% +and so J down with n is either plus or +minus one and so I just get the area of + + align:start position:0% +minus one and so I just get the area of + + + align:start position:0% +minus one and so I just get the area of +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +r as a with a plus or minus and oh that + + align:start position:0% +r as a with a plus or minus and oh that + + + align:start position:0% +r as a with a plus or minus and oh that +doesn't look like a plus or minus with a + + align:start position:0% +doesn't look like a plus or minus with a + + + align:start position:0% +doesn't look like a plus or minus with a +plus or minus in + + align:start position:0% +plus or minus in + + + align:start position:0% +plus or minus in +front Okay depending on whether J dotted + + align:start position:0% +front Okay depending on whether J dotted + + + align:start position:0% +front Okay depending on whether J dotted +with n is one or whether J dotted with n + + align:start position:0% +with n is one or whether J dotted with n + + + align:start position:0% +with n is one or whether J dotted with n +is minus one so the solution for for + + align:start position:0% +is minus one so the solution for for + + + align:start position:0% +is minus one so the solution for for +this computation is just the area of r + + align:start position:0% +this computation is just the area of r + + + align:start position:0% +this computation is just the area of r +or minus the area of R well what's the + + align:start position:0% +or minus the area of R well what's the + + + align:start position:0% +or minus the area of R well what's the +area of the region the area it's a + + align:start position:0% +area of the region the area it's a + + + align:start position:0% +area of the region the area it's a +square of side length one so it has area + + align:start position:0% +square of side length one so it has area + + + align:start position:0% +square of side length one so it has area +one so the final answer is just plus or + + align:start position:0% +one so the final answer is just plus or + + + align:start position:0% +one so the final answer is just plus or +minus + + align:start position:0% +minus + + + align:start position:0% +minus +one so again let me remind you what + + align:start position:0% +one so again let me remind you what + + + align:start position:0% +one so again let me remind you what +we're trying to do we're trying to do + + align:start position:0% +we're trying to do we're trying to do + + + align:start position:0% +we're trying to do we're trying to do +determine these some fluxes of vector + + align:start position:0% +determine these some fluxes of vector + + + align:start position:0% +determine these some fluxes of vector +Fields across surfaces without doing a + + align:start position:0% +Fields across surfaces without doing a + + + align:start position:0% +Fields across surfaces without doing a +lot of calculation + + align:start position:0% +lot of calculation + + + align:start position:0% +lot of calculation +and in the first case we had a vector + + align:start position:0% +and in the first case we had a vector + + + align:start position:0% +and in the first case we had a vector +field that pointed in the Z Direction + + align:start position:0% +field that pointed in the Z Direction + + + align:start position:0% +field that pointed in the Z Direction +only and the normal was only in the X + + align:start position:0% +only and the normal was only in the X + + + align:start position:0% +only and the normal was only in the X +and Y Direction and so the flux was zero + + align:start position:0% +and Y Direction and so the flux was zero + + + align:start position:0% +and Y Direction and so the flux was zero +even though it was a vector field on an + + align:start position:0% +even though it was a vector field on an + + + align:start position:0% +even though it was a vector field on an +infinite cylinder the flux was still + + align:start position:0% +infinite cylinder the flux was still + + + align:start position:0% +infinite cylinder the flux was still +zero and in the other case I had + + align:start position:0% +zero and in the other case I had + + + align:start position:0% +zero and in the other case I had +actually here I had some I had a surface + + align:start position:0% +actually here I had some I had a surface + + + align:start position:0% +actually here I had some I had a surface +that was exactly in the XZ plane and so + + align:start position:0% +that was exactly in the XZ plane and so + + + align:start position:0% +that was exactly in the XZ plane and so +its normal was exactly either in the + + align:start position:0% +its normal was exactly either in the + + + align:start position:0% +its normal was exactly either in the +same direction as J or 180° around from + + align:start position:0% +same direction as J or 180° around from + + + align:start position:0% +same direction as J or 180° around from +J so J dotted with the normal was either + + align:start position:0% +J so J dotted with the normal was either + + + align:start position:0% +J so J dotted with the normal was either +plus or minus one and so I only had to + + align:start position:0% +plus or minus one and so I only had to + + + align:start position:0% +plus or minus one and so I only had to +know the area of the region which is why + + align:start position:0% +know the area of the region which is why + + + align:start position:0% +know the area of the region which is why +it didn't matter where I moved this unit + + align:start position:0% +it didn't matter where I moved this unit + + + align:start position:0% +it didn't matter where I moved this unit +Square I didn't tell you where the unit + + align:start position:0% +Square I didn't tell you where the unit + + + align:start position:0% +Square I didn't tell you where the unit +Square had to sit so that's where you + + align:start position:0% +Square had to sit so that's where you + + + align:start position:0% +Square had to sit so that's where you +can see why it didn't matter because + + align:start position:0% +can see why it didn't matter because + + + align:start position:0% +can see why it didn't matter because +it's just the area okay I think that's + + align:start position:0% +it's just the area okay I think that's + + + align:start position:0% +it's just the area okay I think that's +where I'll stop \ No newline at end of file diff --git a/CWkh5kb4TGc.txt b/CWkh5kb4TGc.txt new file mode 100644 index 0000000000000000000000000000000000000000..6eb7d148adfcc997dd104eb708d9b9b9eba7e7e6 --- /dev/null +++ b/CWkh5kb4TGc.txt @@ -0,0 +1,1643 @@ +align:start position:0% + +the issue of the approximate rate at + + align:start position:0% +the issue of the approximate rate at + + + align:start position:0% +the issue of the approximate rate at +which things happen + + align:start position:0% +which things happen + + + align:start position:0% +which things happen +is common in a lot of science is the + + align:start position:0% +is common in a lot of science is the + + + align:start position:0% +is common in a lot of science is the +rate at which things fall + + align:start position:0% +rate at which things fall + + + align:start position:0% +rate at which things fall +the rate at which reactions occur and in + + align:start position:0% +the rate at which reactions occur and in + + + align:start position:0% +the rate at which reactions occur and in +computer science + + align:start position:0% +computer science + + + align:start position:0% +computer science +typical concern about growth rates comes + + align:start position:0% +typical concern about growth rates comes + + + align:start position:0% +typical concern about growth rates comes +up in + + align:start position:0% +up in + + + align:start position:0% +up in +looking at the efficiency of algorithms + + align:start position:0% +looking at the efficiency of algorithms + + + align:start position:0% +looking at the efficiency of algorithms +and whether they're growing linearly or + + align:start position:0% +and whether they're growing linearly or + + + align:start position:0% +and whether they're growing linearly or +quadratically + + align:start position:0% +quadratically + + + align:start position:0% +quadratically +or more and we're going to look + + align:start position:0% +or more and we're going to look + + + align:start position:0% +or more and we're going to look +today at four notations that describe + + align:start position:0% +today at four notations that describe + + + align:start position:0% +today at four notations that describe +relations between the growth rates of + + align:start position:0% +relations between the growth rates of + + + align:start position:0% +relations between the growth rates of +functions + + align:start position:0% +functions + + + align:start position:0% +functions +the first of these relations is the + + align:start position:0% +the first of these relations is the + + + align:start position:0% +the first of these relations is the +simplest one it's called asymptotic + + align:start position:0% +simplest one it's called asymptotic + + + align:start position:0% +simplest one it's called asymptotic +equivalence or asymptotic equality so + + align:start position:0% +equivalence or asymptotic equality so + + + align:start position:0% +equivalence or asymptotic equality so +this + + align:start position:0% +this + + + align:start position:0% +this +uh tilde symbol is read as + + align:start position:0% +uh tilde symbol is read as + + + align:start position:0% +uh tilde symbol is read as +asymptotically equal to so f of n is + + align:start position:0% +asymptotically equal to so f of n is + + + align:start position:0% +asymptotically equal to so f of n is +asymptotically equal to g of n if and + + align:start position:0% +asymptotically equal to g of n if and + + + align:start position:0% +asymptotically equal to g of n if and +only if + + align:start position:0% +only if + + + align:start position:0% +only if +the limit of the quotient of f of n over + + align:start position:0% +the limit of the quotient of f of n over + + + align:start position:0% +the limit of the quotient of f of n over +g of n + + align:start position:0% +g of n + + + align:start position:0% +g of n +is one let's look at an example + + align:start position:0% +is one let's look at an example + + + align:start position:0% +is one let's look at an example +um n squared is asymptotically equal to + + align:start position:0% +um n squared is asymptotically equal to + + + align:start position:0% +um n squared is asymptotically equal to +n squared plus + + align:start position:0% +n squared plus + + + align:start position:0% +n squared plus +n why is that well it follows trivially + + align:start position:0% +n why is that well it follows trivially + + + align:start position:0% +n why is that well it follows trivially +by manipulating + + align:start position:0% +by manipulating + + + align:start position:0% +by manipulating +the algebra uh the limit of n squared + + align:start position:0% +the algebra uh the limit of n squared + + + align:start position:0% +the algebra uh the limit of n squared +plus n + + align:start position:0% +plus n + + + align:start position:0% +plus n +over n squared simplifying is just the + + align:start position:0% +over n squared simplifying is just the + + + align:start position:0% +over n squared simplifying is just the +same as the limit of 1 + + align:start position:0% +same as the limit of 1 + + + align:start position:0% +same as the limit of 1 +plus 1 over n but as n goes to infinity + + align:start position:0% +plus 1 over n but as n goes to infinity + + + align:start position:0% +plus 1 over n but as n goes to infinity +1 over n goes to 0 so the limit is 1 + + align:start position:0% +1 over n goes to 0 so the limit is 1 + + + align:start position:0% +1 over n goes to 0 so the limit is 1 +as claimed those two expressions + + align:start position:0% +as claimed those two expressions + + + align:start position:0% +as claimed those two expressions +or the functions they define n squared + + align:start position:0% +or the functions they define n squared + + + align:start position:0% +or the functions they define n squared +and n squared plus 1 are asymptotically + + align:start position:0% +and n squared plus 1 are asymptotically + + + align:start position:0% +and n squared plus 1 are asymptotically +equal + + align:start position:0% +equal + + + align:start position:0% +equal +some there are some easy properties of + + align:start position:0% +some there are some easy properties of + + + align:start position:0% +some there are some easy properties of +asymptotic equality that follow + + align:start position:0% +asymptotic equality that follow + + + align:start position:0% +asymptotic equality that follow +immediately from the definition + + align:start position:0% +immediately from the definition + + + align:start position:0% +immediately from the definition +one of them is that it's symmetric + + align:start position:0% +one of them is that it's symmetric + + + align:start position:0% +one of them is that it's symmetric +namely suppose that f is asymptotically + + align:start position:0% +namely suppose that f is asymptotically + + + align:start position:0% +namely suppose that f is asymptotically +equal to g + + align:start position:0% +equal to g + + + align:start position:0% +equal to g +i want to prove that g is asymptotically + + align:start position:0% +i want to prove that g is asymptotically + + + align:start position:0% +i want to prove that g is asymptotically +equal to f well what's going on here + + align:start position:0% +equal to f well what's going on here + + + align:start position:0% +equal to f well what's going on here +let's look at the limit of g over f + + align:start position:0% +let's look at the limit of g over f + + + align:start position:0% +let's look at the limit of g over f +which is what i'd like to prove is one + + align:start position:0% +which is what i'd like to prove is one + + + align:start position:0% +which is what i'd like to prove is one +well the limit of g over f by algebra g + + align:start position:0% +well the limit of g over f by algebra g + + + align:start position:0% +well the limit of g over f by algebra g +over f is the same as one over + + align:start position:0% +over f is the same as one over + + + align:start position:0% +over f is the same as one over +f over g so just moving the limit + + align:start position:0% +f over g so just moving the limit + + + align:start position:0% +f over g so just moving the limit +across the division that's the same as + + align:start position:0% +across the division that's the same as + + + align:start position:0% +across the division that's the same as +one over the limit of f over g + + align:start position:0% +one over the limit of f over g + + + align:start position:0% +one over the limit of f over g +which is one over one and we've proved + + align:start position:0% +which is one over one and we've proved + + + align:start position:0% +which is one over one and we've proved +in other words that g + + align:start position:0% +in other words that g + + + align:start position:0% +in other words that g +is asymptotically equal to f given that + + align:start position:0% +is asymptotically equal to f given that + + + align:start position:0% +is asymptotically equal to f given that +f is asymptotically equal to g + + align:start position:0% +f is asymptotically equal to g + + + align:start position:0% +f is asymptotically equal to g +it's symmetric there's a similar + + align:start position:0% +it's symmetric there's a similar + + + align:start position:0% +it's symmetric there's a similar +argument for transitivity let's just + + align:start position:0% +argument for transitivity let's just + + + align:start position:0% +argument for transitivity let's just +crank through it for practice on the + + align:start position:0% +crank through it for practice on the + + + align:start position:0% +crank through it for practice on the +definition suppose that f + + align:start position:0% +definition suppose that f + + + align:start position:0% +definition suppose that f +is asymptotically equal to g and g is + + align:start position:0% +is asymptotically equal to g and g is + + + align:start position:0% +is asymptotically equal to g and g is +asymptotically equal to h i'd like to + + align:start position:0% +asymptotically equal to h i'd like to + + + align:start position:0% +asymptotically equal to h i'd like to +prove that + + align:start position:0% +prove that + + + align:start position:0% +prove that +f is asymptotically equal to h + + align:start position:0% +f is asymptotically equal to h + + + align:start position:0% +f is asymptotically equal to h +well again we just plug into the + + align:start position:0% +well again we just plug into the + + + align:start position:0% +well again we just plug into the +algebra and distribute limits let's just + + align:start position:0% +algebra and distribute limits let's just + + + align:start position:0% +algebra and distribute limits let's just +look at this we're given that one + + align:start position:0% +look at this we're given that one + + + align:start position:0% +look at this we're given that one +is the limit of f over g because f is + + align:start position:0% +is the limit of f over g because f is + + + align:start position:0% +is the limit of f over g because f is +asymptotic to g + + align:start position:0% +asymptotic to g + + + align:start position:0% +asymptotic to g +but f over g can be expressed as f over + + align:start position:0% +but f over g can be expressed as f over + + + align:start position:0% +but f over g can be expressed as f over +h divided by g + + align:start position:0% +h divided by g + + + align:start position:0% +h divided by g +over h that's just algebra the h's + + align:start position:0% +over h that's just algebra the h's + + + align:start position:0% +over h that's just algebra the h's +cancel + + align:start position:0% +cancel + + + align:start position:0% +cancel +so this limit now i can distribute the + + align:start position:0% +so this limit now i can distribute the + + + align:start position:0% +so this limit now i can distribute the +limits to the numerator and denominator + + align:start position:0% +limits to the numerator and denominator + + + align:start position:0% +limits to the numerator and denominator +assuming both exist and the numerator + + align:start position:0% +assuming both exist and the numerator + + + align:start position:0% +assuming both exist and the numerator +limit + + align:start position:0% +limit + + + align:start position:0% +limit +is what i'm interested in the + + align:start position:0% +is what i'm interested in the + + + align:start position:0% +is what i'm interested in the +denominator limit is going to be + + align:start position:0% +denominator limit is going to be + + + align:start position:0% +denominator limit is going to be +1 because the limit of g over h is one + + align:start position:0% +1 because the limit of g over h is one + + + align:start position:0% +1 because the limit of g over h is one +since g is asymptotically equal to h the + + align:start position:0% +since g is asymptotically equal to h the + + + align:start position:0% +since g is asymptotically equal to h the +conclusion is indeed + + align:start position:0% +conclusion is indeed + + + align:start position:0% +conclusion is indeed +that the limit of f over h is equal to + + align:start position:0% +that the limit of f over h is equal to + + + align:start position:0% +that the limit of f over h is equal to +one + + align:start position:0% +one + + + align:start position:0% +one +this is not really very interesting + + align:start position:0% +this is not really very interesting + + + align:start position:0% +this is not really very interesting +stuff + + align:start position:0% +stuff + + + align:start position:0% +stuff +and the top level message is that many + + align:start position:0% +and the top level message is that many + + + align:start position:0% +and the top level message is that many +of these + + align:start position:0% +of these + + + align:start position:0% +of these +elementary properties of asymptotic + + align:start position:0% +elementary properties of asymptotic + + + align:start position:0% +elementary properties of asymptotic +equality + + align:start position:0% +equality + + + align:start position:0% +equality +and the other asymptotic relations that + + align:start position:0% +and the other asymptotic relations that + + + align:start position:0% +and the other asymptotic relations that +we're going to see + + align:start position:0% +we're going to see + + + align:start position:0% +we're going to see +follow by this kind of elementary + + align:start position:0% +follow by this kind of elementary + + + align:start position:0% +follow by this kind of elementary +algebra and distributing + + align:start position:0% +algebra and distributing + + + align:start position:0% +algebra and distributing +the limits over sub-expressions + + align:start position:0% +the limits over sub-expressions + + + align:start position:0% +the limits over sub-expressions +anyway uh the corollary of this is that + + align:start position:0% +anyway uh the corollary of this is that + + + align:start position:0% +anyway uh the corollary of this is that +asymptotic equality + + align:start position:0% +asymptotic equality + + + align:start position:0% +asymptotic equality +is in fact an equivalence relation we've + + align:start position:0% +is in fact an equivalence relation we've + + + align:start position:0% +is in fact an equivalence relation we've +proved it's symmetric and transitive and + + align:start position:0% +proved it's symmetric and transitive and + + + align:start position:0% +proved it's symmetric and transitive and +it's trivially + + align:start position:0% +it's trivially + + + align:start position:0% +it's trivially +reflexive it's an equivalence relation + + align:start position:0% +reflexive it's an equivalence relation + + + align:start position:0% +reflexive it's an equivalence relation +by the way it's worth noting that it's + + align:start position:0% +by the way it's worth noting that it's + + + align:start position:0% +by the way it's worth noting that it's +an equivalence relation on + + align:start position:0% +an equivalence relation on + + + align:start position:0% +an equivalence relation on +functions of one variable when we write + + align:start position:0% +functions of one variable when we write + + + align:start position:0% +functions of one variable when we write +sometimes that + + align:start position:0% +sometimes that + + + align:start position:0% +sometimes that +f of n is asymptotically equal to g of n + + align:start position:0% +f of n is asymptotically equal to g of n + + + align:start position:0% +f of n is asymptotically equal to g of n +but we mean that f of n is the + + align:start position:0% +but we mean that f of n is the + + + align:start position:0% +but we mean that f of n is the +description of a function + + align:start position:0% +description of a function + + + align:start position:0% +description of a function +f we're not talking about the number + + align:start position:0% +f we're not talking about the number + + + align:start position:0% +f we're not talking about the number +that f n happens to have for some + + align:start position:0% +that f n happens to have for some + + + align:start position:0% +that f n happens to have for some +particular value of f + + align:start position:0% +particular value of f + + + align:start position:0% +particular value of f +so while we'll sometimes write f of n is + + align:start position:0% +so while we'll sometimes write f of n is + + + align:start position:0% +so while we'll sometimes write f of n is +asymptotically equal to g + + align:start position:0% +asymptotically equal to g + + + align:start position:0% +asymptotically equal to g +of n for descriptive purposes the proper + + align:start position:0% +of n for descriptive purposes the proper + + + align:start position:0% +of n for descriptive purposes the proper +thing we should be writing is that f is + + align:start position:0% +thing we should be writing is that f is + + + align:start position:0% +thing we should be writing is that f is +asymptotically equal to g + + align:start position:0% +asymptotically equal to g + + + align:start position:0% +asymptotically equal to g +asymptotic equality is a relation + + align:start position:0% +asymptotic equality is a relation + + + align:start position:0% +asymptotic equality is a relation +between functions + + align:start position:0% +between functions + + + align:start position:0% +between functions +okay the next asymptotic relation we're + + align:start position:0% +okay the next asymptotic relation we're + + + align:start position:0% +okay the next asymptotic relation we're +going to look at is called + + align:start position:0% +going to look at is called + + + align:start position:0% +going to look at is called +asymptotically smaller than + + align:start position:0% +asymptotically smaller than + + + align:start position:0% +asymptotically smaller than +and it's the notation for it is this + + align:start position:0% +and it's the notation for it is this + + + align:start position:0% +and it's the notation for it is this +little o notation so you'd write + + align:start position:0% +little o notation so you'd write + + + align:start position:0% +little o notation so you'd write +that f of n is equal to little o of g of + + align:start position:0% +that f of n is equal to little o of g of + + + align:start position:0% +that f of n is equal to little o of g of +n + + align:start position:0% +n + + + align:start position:0% +n +if and only if the limit of f of n + + align:start position:0% +if and only if the limit of f of n + + + align:start position:0% +if and only if the limit of f of n +over g of n goes to zero as n approaches + + align:start position:0% +over g of n goes to zero as n approaches + + + align:start position:0% +over g of n goes to zero as n approaches +infinity + + align:start position:0% +infinity + + + align:start position:0% +infinity +so let's look at an example of that n + + align:start position:0% +so let's look at an example of that n + + + align:start position:0% +so let's look at an example of that n +squared is little o of n + + align:start position:0% +squared is little o of n + + + align:start position:0% +squared is little o of n +cubed because trivially the limit of n + + align:start position:0% +cubed because trivially the limit of n + + + align:start position:0% +cubed because trivially the limit of n +squared over n cubed is the same as the + + align:start position:0% +squared over n cubed is the same as the + + + align:start position:0% +squared over n cubed is the same as the +limit of one over n it's equal to zero + + align:start position:0% +limit of one over n it's equal to zero + + + align:start position:0% +limit of one over n it's equal to zero +and by similar kind of reasoning that we + + align:start position:0% +and by similar kind of reasoning that we + + + align:start position:0% +and by similar kind of reasoning that we +did for asymptotic equality being an + + align:start position:0% +did for asymptotic equality being an + + + align:start position:0% +did for asymptotic equality being an +equivalence relation it's not very hard + + align:start position:0% +equivalence relation it's not very hard + + + align:start position:0% +equivalence relation it's not very hard +to prove + + align:start position:0% +to prove + + + align:start position:0% +to prove +that uh that little o defines a strict + + align:start position:0% +that uh that little o defines a strict + + + align:start position:0% +that uh that little o defines a strict +partial order + + align:start position:0% +partial order + + + align:start position:0% +partial order +on functions + + align:start position:0% + + + + align:start position:0% + +so the third relation asymptotic + + align:start position:0% +so the third relation asymptotic + + + align:start position:0% +so the third relation asymptotic +relation is the most + + align:start position:0% +relation is the most + + + align:start position:0% +relation is the most +complicated of the three although it's + + align:start position:0% +complicated of the three although it's + + + align:start position:0% +complicated of the three although it's +arguably the most important in computer + + align:start position:0% +arguably the most important in computer + + + align:start position:0% +arguably the most important in computer +science + + align:start position:0% +science + + + align:start position:0% +science +it's called the asymptotic order of + + align:start position:0% +it's called the asymptotic order of + + + align:start position:0% +it's called the asymptotic order of +growth big o + + align:start position:0% +growth big o + + + align:start position:0% +growth big o +and the definition is that a function f + + align:start position:0% +and the definition is that a function f + + + align:start position:0% +and the definition is that a function f +is big o + + align:start position:0% +is big o + + + align:start position:0% +is big o +of a function g what it means is + + align:start position:0% +of a function g what it means is + + + align:start position:0% +of a function g what it means is +that the limit of f over g is finite + + align:start position:0% +that the limit of f over g is finite + + + align:start position:0% +that the limit of f over g is finite +so it's it might be other than zero or + + align:start position:0% +so it's it might be other than zero or + + + align:start position:0% +so it's it might be other than zero or +one + + align:start position:0% +one + + + align:start position:0% +one +but it's finite and that means that f + + align:start position:0% +but it's finite and that means that f + + + align:start position:0% +but it's finite and that means that f +is big o of g now there's a technicality + + align:start position:0% +is big o of g now there's a technicality + + + align:start position:0% +is big o of g now there's a technicality +there + + align:start position:0% +there + + + align:start position:0% +there +where the expression actually says the + + align:start position:0% +where the expression actually says the + + + align:start position:0% +where the expression actually says the +limb soup + + align:start position:0% +limb soup + + + align:start position:0% +limb soup +of f of n over g of n let's just ignore + + align:start position:0% +of f of n over g of n let's just ignore + + + align:start position:0% +of f of n over g of n let's just ignore +that for now and we'll look at it + + align:start position:0% +that for now and we'll look at it + + + align:start position:0% +that for now and we'll look at it +uh uh and explain why the limb soup is + + align:start position:0% +uh uh and explain why the limb soup is + + + align:start position:0% +uh uh and explain why the limb soup is +there a little later + + align:start position:0% +there a little later + + + align:start position:0% +there a little later +so as an example 3n + + align:start position:0% +so as an example 3n + + + align:start position:0% +so as an example 3n +squared is big o of n squared + + align:start position:0% +squared is big o of n squared + + + align:start position:0% +squared is big o of n squared +because the quotient of 3n squared over + + align:start position:0% +because the quotient of 3n squared over + + + align:start position:0% +because the quotient of 3n squared over +n squared is 3 + + align:start position:0% +n squared is 3 + + + align:start position:0% +n squared is 3 +which is less than infinity so what big + + align:start position:0% +which is less than infinity so what big + + + align:start position:0% +which is less than infinity so what big +o is doing is kind of saying that + + align:start position:0% +o is doing is kind of saying that + + + align:start position:0% +o is doing is kind of saying that +constant factors don't matter + + align:start position:0% +constant factors don't matter + + + align:start position:0% +constant factors don't matter +and that turns out to be particularly + + align:start position:0% +and that turns out to be particularly + + + align:start position:0% +and that turns out to be particularly +useful in computer science where + + align:start position:0% +useful in computer science where + + + align:start position:0% +useful in computer science where +you can't really talk about the time + + align:start position:0% +you can't really talk about the time + + + align:start position:0% +you can't really talk about the time +that a procedure takes because that's + + align:start position:0% +that a procedure takes because that's + + + align:start position:0% +that a procedure takes because that's +going to depend on the hardware + + align:start position:0% +going to depend on the hardware + + + align:start position:0% +going to depend on the hardware +so when you implement it on faster + + align:start position:0% +so when you implement it on faster + + + align:start position:0% +so when you implement it on faster +hardware + + align:start position:0% +hardware + + + align:start position:0% +hardware +it may grow at the same rate but the + + align:start position:0% +it may grow at the same rate but the + + + align:start position:0% +it may grow at the same rate but the +time will actually change + + align:start position:0% +time will actually change + + + align:start position:0% +time will actually change +and that's why big o plays a prominent + + align:start position:0% +and that's why big o plays a prominent + + + align:start position:0% +and that's why big o plays a prominent +role + + align:start position:0% +role + + + align:start position:0% +role +the final relation of the four is called + + align:start position:0% +the final relation of the four is called + + + align:start position:0% +the final relation of the four is called +theta or same order of growth the + + align:start position:0% +theta or same order of growth the + + + align:start position:0% +theta or same order of growth the +definition + + align:start position:0% +definition + + + align:start position:0% +definition +of f is theta of g is simply + + align:start position:0% +of f is theta of g is simply + + + align:start position:0% +of f is theta of g is simply +that f is o of g and g is o of + + align:start position:0% +that f is o of g and g is o of + + + align:start position:0% +that f is o of g and g is o of +f and it's easy to show from the + + align:start position:0% +f and it's easy to show from the + + + align:start position:0% +f and it's easy to show from the +definition that theta + + align:start position:0% +definition that theta + + + align:start position:0% +definition that theta +is an equivalence relation so to + + align:start position:0% +is an equivalence relation so to + + + align:start position:0% +is an equivalence relation so to +summarize + + align:start position:0% +summarize + + + align:start position:0% +summarize +there are these four relations um + + align:start position:0% +there are these four relations um + + + align:start position:0% +there are these four relations um +f asymptotically equal to g means that + + align:start position:0% +f asymptotically equal to g means that + + + align:start position:0% +f asymptotically equal to g means that +informally that f and g are nearly equal + + align:start position:0% +informally that f and g are nearly equal + + + align:start position:0% +informally that f and g are nearly equal +um f equals little o of j informally + + align:start position:0% +um f equals little o of j informally + + + align:start position:0% +um f equals little o of j informally +means that f is much less than g + + align:start position:0% +means that f is much less than g + + + align:start position:0% +means that f is much less than g +f equals o of g means that f is roughly + + align:start position:0% +f equals o of g means that f is roughly + + + align:start position:0% +f equals o of g means that f is roughly +less than or equal to g where roughly + + align:start position:0% +less than or equal to g where roughly + + + align:start position:0% +less than or equal to g where roughly +means that we're not concerned about + + align:start position:0% +means that we're not concerned about + + + align:start position:0% +means that we're not concerned about +constant factors + + align:start position:0% +constant factors + + + align:start position:0% +constant factors +and f equals theta of g means that f is + + align:start position:0% +and f equals theta of g means that f is + + + align:start position:0% +and f equals theta of g means that f is +roughly + + align:start position:0% +roughly + + + align:start position:0% +roughly +equal to g and we'll examine these + + align:start position:0% +equal to g and we'll examine these + + + align:start position:0% +equal to g and we'll examine these +properties in more detail in the next + + align:start position:0% +properties in more detail in the next + + + align:start position:0% +properties in more detail in the next +segment \ No newline at end of file diff --git a/DdnXB0Fa3gQ.txt b/DdnXB0Fa3gQ.txt new file mode 100644 index 0000000000000000000000000000000000000000..09edfad5f4db8f7cbea8ffa6e30e67a569d603f0 --- /dev/null +++ b/DdnXB0Fa3gQ.txt @@ -0,0 +1,13339 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +view additional materials from hundreds + + align:start position:0% +view additional materials from hundreds + + + align:start position:0% +view additional materials from hundreds +of MIT courses visit MIT opencourseware + + align:start position:0% +of MIT courses visit MIT opencourseware + + + align:start position:0% +of MIT courses visit MIT opencourseware +at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu so where were + + align:start position:0% +ocw.mit.edu so where were + + + align:start position:0% +ocw.mit.edu so where were +we so last time we were talking about + + align:start position:0% +we so last time we were talking about + + + align:start position:0% +we so last time we were talking about +MSR scheme and + + align:start position:0% +MSR scheme and + + + align:start position:0% +MSR scheme and +renormalons and so we talked about the + + align:start position:0% +renormalons and so we talked about the + + + align:start position:0% +renormalons and so we talked about the +msar scheme we talked about renormalons + + align:start position:0% +msar scheme we talked about renormalons + + + align:start position:0% +msar scheme we talked about renormalons +and we said that we could introduce a + + align:start position:0% +and we said that we could introduce a + + + align:start position:0% +and we said that we could introduce a +mass scheme that has an arbitrary power + + align:start position:0% +mass scheme that has an arbitrary power + + + align:start position:0% +mass scheme that has an arbitrary power +law cut off which we called R to + + align:start position:0% +law cut off which we called R to + + + align:start position:0% +law cut off which we called R to +distinguish it from mu or Lambda or some + + align:start position:0% +distinguish it from mu or Lambda or some + + + align:start position:0% +distinguish it from mu or Lambda or some +other cut + + align:start position:0% +other cut + + + align:start position:0% +other cut +off and so the idea of + + align:start position:0% +off and so the idea of + + + align:start position:0% +off and so the idea of +this scheme right here was to go was to + + align:start position:0% +this scheme right here was to go was to + + + align:start position:0% +this scheme right here was to go was to +have a way of perturbing away from Ms + + align:start position:0% +have a way of perturbing away from Ms + + + align:start position:0% +have a way of perturbing away from Ms +bar to get rid of this renormalon + + align:start position:0% +bar to get rid of this renormalon + + + align:start position:0% +bar to get rid of this renormalon +problem that msar has but retain all the + + align:start position:0% +problem that msar has but retain all the + + + align:start position:0% +problem that msar has but retain all the +nice features of + + align:start position:0% +nice features of + + + align:start position:0% +nice features of +msar in particular we don't really want + + align:start position:0% +msar in particular we don't really want + + + align:start position:0% +msar in particular we don't really want +to calculate anything new if we can + + align:start position:0% +to calculate anything new if we can + + + align:start position:0% +to calculate anything new if we can +avoid it and that's what this scheme + + align:start position:0% +avoid it and that's what this scheme + + + align:start position:0% +avoid it and that's what this scheme +does + + align:start position:0% +does + + + align:start position:0% +does +because really what it does is it uses + + align:start position:0% +because really what it does is it uses + + + align:start position:0% +because really what it does is it uses +the fact that we know that the msar + + align:start position:0% +the fact that we know that the msar + + + align:start position:0% +the fact that we know that the msar +scheme has this + + align:start position:0% +scheme has this + + + align:start position:0% +scheme has this +renormalon so this series here has a + + align:start position:0% +renormalon so this series here has a + + + align:start position:0% +renormalon so this series here has a +renormalon and it just takes that series + + align:start position:0% +renormalon and it just takes that series + + + align:start position:0% +renormalon and it just takes that series +over from msar puts it in with a cut off + + align:start position:0% +over from msar puts it in with a cut off + + + align:start position:0% +over from msar puts it in with a cut off +which is this R and defines a new Mass + + align:start position:0% +which is this R and defines a new Mass + + + align:start position:0% +which is this R and defines a new Mass +scheme using that + + align:start position:0% +scheme using that + + + align:start position:0% +scheme using that +formula uh so this is like a mass scheme + + align:start position:0% +formula uh so this is like a mass scheme + + + align:start position:0% +formula uh so this is like a mass scheme +that has an adjust trustable cut off + + align:start position:0% +that has an adjust trustable cut off + + + align:start position:0% +that has an adjust trustable cut off +which we can take to be at whatever + + align:start position:0% +which we can take to be at whatever + + + align:start position:0% +which we can take to be at whatever +scale we want and in particular in HQ + + align:start position:0% +scale we want and in particular in HQ + + + align:start position:0% +scale we want and in particular in HQ +you'd want to take that R to be + + align:start position:0% +you'd want to take that R to be + + + align:start position:0% +you'd want to take that R to be +something like a GV type scale because + + align:start position:0% +something like a GV type scale because + + + align:start position:0% +something like a GV type scale because +that wouldn't spoil your power + + align:start position:0% +that wouldn't spoil your power + + + align:start position:0% +that wouldn't spoil your power +counting so recall in HQ that this Delta + + align:start position:0% +counting so recall in HQ that this Delta + + + align:start position:0% +counting so recall in HQ that this Delta +M should be by power countings of Border + + align:start position:0% +M should be by power countings of Border + + + align:start position:0% +M should be by power countings of Border +Lambda qcd + + align:start position:0% +Lambda qcd + + + align:start position:0% +Lambda qcd +so typically you would take R somewhat + + align:start position:0% +so typically you would take R somewhat + + + align:start position:0% +so typically you would take R somewhat +greater than Lambda qcd bit of order + + align:start position:0% +greater than Lambda qcd bit of order + + + align:start position:0% +greater than Lambda qcd bit of order +Lambda qcd + + align:start position:0% + + + + align:start position:0% + +okay so now we have this extra cut off + + align:start position:0% +okay so now we have this extra cut off + + + align:start position:0% +okay so now we have this extra cut off +so when we have a cut off we have a + + align:start position:0% +so when we have a cut off we have a + + + align:start position:0% +so when we have a cut off we have a +renormalization group and if you think + + align:start position:0% +renormalization group and if you think + + + align:start position:0% +renormalization group and if you think +about the renormalization group for Ms + + align:start position:0% +about the renormalization group for Ms + + + align:start position:0% +about the renormalization group for Ms +bar Mass it would be something like mu D + + align:start position:0% +bar Mass it would be something like mu D + + + align:start position:0% +bar Mass it would be something like mu D +byd mu of M of mu is equal to anomalous + + align:start position:0% +byd mu of M of mu is equal to anomalous + + + align:start position:0% +byd mu of M of mu is equal to anomalous +Dimension time M of mu back again this + + align:start position:0% +Dimension time M of mu back again this + + + align:start position:0% +Dimension time M of mu back again this +one's a little different it's r d byd r + + align:start position:0% +one's a little different it's r d byd r + + + align:start position:0% +one's a little different it's r d byd r +of M of R and then there's no M on the + + align:start position:0% +of M of R and then there's no M on the + + + align:start position:0% +of M of R and then there's no M on the +right hand side it's an additive + + align:start position:0% +right hand side it's an additive + + + align:start position:0% +right hand side it's an additive +normalization to get rid of the r normal + + align:start position:0% +normalization to get rid of the r normal + + + align:start position:0% +normalization to get rid of the r normal +on and there's a power also of R here + + align:start position:0% +on and there's a power also of R here + + + align:start position:0% +on and there's a power also of R here +okay so it's not just it's not just + + align:start position:0% +okay so it's not just it's not just + + + align:start position:0% +okay so it's not just it's not just +summing log logs it's it is summing some + + align:start position:0% +summing log logs it's it is summing some + + + align:start position:0% +summing log logs it's it is summing some +logs related to the running of alpha but + + align:start position:0% +logs related to the running of alpha but + + + align:start position:0% +logs related to the running of alpha but +it's also got this power and when you + + align:start position:0% +it's also got this power and when you + + + align:start position:0% +it's also got this power and when you +solve this anom almost Dimension + + align:start position:0% +solve this anom almost Dimension + + + align:start position:0% +solve this anom almost Dimension +equation which we talked about last time + + align:start position:0% +equation which we talked about last time + + + align:start position:0% +equation which we talked about last time +you get an integral like this in this T + + align:start position:0% +you get an integral like this in this T + + + align:start position:0% +you get an integral like this in this T +variable and at leading log order it + + align:start position:0% +variable and at leading log order it + + + align:start position:0% +variable and at leading log order it +looks like this difference of two + + align:start position:0% +looks like this difference of two + + + align:start position:0% +looks like this difference of two +incomplete gamma functions because of + + align:start position:0% +incomplete gamma functions because of + + + align:start position:0% +incomplete gamma functions because of +the mass Dimensions it has to be made up + + align:start position:0% +the mass Dimensions it has to be made up + + + align:start position:0% +the mass Dimensions it has to be made up +by mass dimensions on the right hand + + align:start position:0% +by mass dimensions on the right hand + + + align:start position:0% +by mass dimensions on the right hand +side coupling is dimensionless the only + + align:start position:0% +side coupling is dimensionless the only + + + align:start position:0% +side coupling is dimensionless the only +thing that has Dimensions is Lambda qcd + + align:start position:0% +thing that has Dimensions is Lambda qcd + + + align:start position:0% +thing that has Dimensions is Lambda qcd +and that's exactly what pops out of + + align:start position:0% +and that's exactly what pops out of + + + align:start position:0% +and that's exactly what pops out of +solving this equation the r gets + + align:start position:0% +solving this equation the r gets + + + align:start position:0% +solving this equation the r gets +converted to a Lambda qcd by this + + align:start position:0% +converted to a Lambda qcd by this + + + align:start position:0% +converted to a Lambda qcd by this +formula + + align:start position:0% +formula + + + align:start position:0% +formula +here this G of T was just T at lowest + + align:start position:0% +here this G of T was just T at lowest + + + align:start position:0% +here this G of T was just T at lowest +order so this is an all order form here + + align:start position:0% +order so this is an all order form here + + + align:start position:0% +order so this is an all order form here +and this is the leading log solution + + align:start position:0% +and this is the leading log solution + + + align:start position:0% +and this is the leading log solution +there so if we look at that leading log + + align:start position:0% +there so if we look at that leading log + + + align:start position:0% +there so if we look at that leading log +and what is the T t0 and the T1 that's + + align:start position:0% +and what is the T t0 and the T1 that's + + + align:start position:0% +and what is the T t0 and the T1 that's +just the the same formula here but with + + align:start position:0% +just the the same formula here but with + + + align:start position:0% +just the the same formula here but with +Alpha at R1 and r0 the boundary + + align:start position:0% +Alpha at R1 and r0 the boundary + + + align:start position:0% +Alpha at R1 and r0 the boundary +conditions we want to run from r0 to R1 + + align:start position:0% +conditions we want to run from r0 to R1 + + + align:start position:0% +conditions we want to run from r0 to R1 +and this formula tells us how to do that + + align:start position:0% +and this formula tells us how to do that + + + align:start position:0% +and this formula tells us how to do that +and and we get a result here that has + + align:start position:0% +and and we get a result here that has + + + align:start position:0% +and and we get a result here that has +the coupling at r0 and the coupling at + + align:start position:0% +the coupling at r0 and the coupling at + + + align:start position:0% +the coupling at r0 and the coupling at +R1 okay so if we look at that result + + align:start position:0% +R1 okay so if we look at that result + + + align:start position:0% +R1 okay so if we look at that result +it's interesting because if we just had + + align:start position:0% +it's interesting because if we just had + + + align:start position:0% +it's interesting because if we just had +one of these gamma functions these + + align:start position:0% +one of these gamma functions these + + + align:start position:0% +one of these gamma functions these +incomplete gamma functions then we would + + align:start position:0% +incomplete gamma functions then we would + + + align:start position:0% +incomplete gamma functions then we would +have a + + align:start position:0% +have a + + + align:start position:0% +have a +renormalon that's where I stopped last + + align:start position:0% +renormalon that's where I stopped last + + + align:start position:0% +renormalon that's where I stopped last +time + + align:start position:0% +time + + + align:start position:0% +time +so just looking at this Lambda qcd times + + align:start position:0% +so just looking at this Lambda qcd times + + + align:start position:0% +so just looking at this Lambda qcd times +gamma and expanding about the in a + + align:start position:0% +gamma and expanding about the in a + + + align:start position:0% +gamma and expanding about the in a +series of about zero which is expanding + + align:start position:0% +series of about zero which is expanding + + + align:start position:0% +series of about zero which is expanding +in in the coupling at + + align:start position:0% +in in the coupling at + + + align:start position:0% +in in the coupling at +Infinity uh you get this series which + + align:start position:0% +Infinity uh you get this series which + + + align:start position:0% +Infinity uh you get this series which +has a 2 the n and factorial it's an ASM + + align:start position:0% +has a 2 the n and factorial it's an ASM + + + align:start position:0% +has a 2 the n and factorial it's an ASM +totic Series this is a classic example + + align:start position:0% +totic Series this is a classic example + + + align:start position:0% +totic Series this is a classic example +of a function that has an ASM totic + + align:start position:0% +of a function that has an ASM totic + + + align:start position:0% +of a function that has an ASM totic +Series this incomplete gamma function + + align:start position:0% +Series this incomplete gamma function + + + align:start position:0% +Series this incomplete gamma function +there's some exponential that combines + + align:start position:0% +there's some exponential that combines + + + align:start position:0% +there's some exponential that combines +together with the Lambda qcd to give an + + align:start position:0% +together with the Lambda qcd to give an + + + align:start position:0% +together with the Lambda qcd to give an +R so I've pulled that out front and then + + align:start position:0% +R so I've pulled that out front and then + + + align:start position:0% +R so I've pulled that out front and then +we have this series which is exactly U + + align:start position:0% +we have this series which is exactly U + + + align:start position:0% +we have this series which is exactly U +equals a half or a normal on and the U + + align:start position:0% +equals a half or a normal on and the U + + + align:start position:0% +equals a half or a normal on and the U +equals a half had to do with this power + + align:start position:0% +equals a half had to do with this power + + + align:start position:0% +equals a half had to do with this power +two to the N here the fact that it's two + + align:start position:0% +two to the N here the fact that it's two + + + align:start position:0% +two to the N here the fact that it's two +to the n and not some other + + align:start position:0% +to the n and not some other + + + align:start position:0% +to the n and not some other +number but if we take the difference + + align:start position:0% +number but if we take the difference + + + align:start position:0% +number but if we take the difference +here and this is what I said in words + + align:start position:0% +here and this is what I said in words + + + align:start position:0% +here and this is what I said in words +last time but now I'll write it down in + + align:start position:0% +last time but now I'll write it down in + + + align:start position:0% +last time but now I'll write it down in +equations we take the difference there + + align:start position:0% +equations we take the difference there + + + align:start position:0% +equations we take the difference there +that actually doesn't have this for + + align:start position:0% +that actually doesn't have this for + + + align:start position:0% +that actually doesn't have this for +normal + + align:start position:0% +normal + + + align:start position:0% +normal +on + + align:start position:0% + + + + align:start position:0% + +so this is the difference of two series + + align:start position:0% +so this is the difference of two series + + + align:start position:0% +so this is the difference of two series +Each of which is Asm totic + + align:start position:0% + + + + align:start position:0% + +if we want to compare those series we + + align:start position:0% +if we want to compare those series we + + + align:start position:0% +if we want to compare those series we +should expand + + align:start position:0% +should expand + + + align:start position:0% +should expand +them in the same coupling + + align:start position:0% + + + + align:start position:0% + +constant so let me do that + + align:start position:0% + + + + align:start position:0% + +so if I take the difference of those two + + align:start position:0% +so if I take the difference of those two + + + align:start position:0% +so if I take the difference of those two +series taking this using this formula + + align:start position:0% +series taking this using this formula + + + align:start position:0% +series taking this using this formula +but now I re-expand all these Alphas in + + align:start position:0% +but now I re-expand all these Alphas in + + + align:start position:0% +but now I re-expand all these Alphas in +terms of Alphas at the R1 scale so when + + align:start position:0% +terms of Alphas at the R1 scale so when + + + align:start position:0% +terms of Alphas at the R1 scale so when +they're at the r zero scale I re-expand + + align:start position:0% +they're at the r zero scale I re-expand + + + align:start position:0% +they're at the r zero scale I re-expand +them in terms of alpha the R1 scale do + + align:start position:0% +them in terms of alpha the R1 scale do + + + align:start position:0% +them in terms of alpha the R1 scale do +some rearranging I can write the result + + align:start position:0% +some rearranging I can write the result + + + align:start position:0% +some rearranging I can write the result +in this form as this so the key thing is + + align:start position:0% +in this form as this so the key thing is + + + align:start position:0% +in this form as this so the key thing is +that difference + + align:start position:0% +that difference + + + align:start position:0% +that difference +there and if you thought think about + + align:start position:0% +there and if you thought think about + + + align:start position:0% +there and if you thought think about +what this sum here is this is like kind + + align:start position:0% +what this sum here is this is like kind + + + align:start position:0% +what this sum here is this is like kind +of like an exponential right something + + align:start position:0% +of like an exponential right something + + + align:start position:0% +of like an exponential right something +to a power K factorial except it's + + align:start position:0% +to a power K factorial except it's + + + align:start position:0% +to a power K factorial except it's +limited to n so if I really went all the + + align:start position:0% +limited to n so if I really went all the + + + align:start position:0% +limited to n so if I really went all the +way up to n equals infinity this would + + align:start position:0% +way up to n equals infinity this would + + + align:start position:0% +way up to n equals infinity this would +be just giving actually exponential of + + align:start position:0% +be just giving actually exponential of + + + align:start position:0% +be just giving actually exponential of +R1 over r0 would cancel the r0 over R1 + + align:start position:0% +R1 over r0 would cancel the r0 over R1 + + + align:start position:0% +R1 over r0 would cancel the r0 over R1 +which would then cancel the + + align:start position:0% +which would then cancel the + + + align:start position:0% +which would then cancel the +one you can rearrange the series a + + align:start position:0% +one you can rearrange the series a + + + align:start position:0% +one you can rearrange the series a +little + + align:start position:0% +little + + + align:start position:0% +little +bit to make it more obvious that it's + + align:start position:0% +bit to make it more obvious that it's + + + align:start position:0% +bit to make it more obvious that it's +convergent + + align:start position:0% + + + + align:start position:0% + +because there is this n factorial here + + align:start position:0% +because there is this n factorial here + + + align:start position:0% +because there is this n factorial here +you might worry well this thing here has + + align:start position:0% +you might worry well this thing here has + + + align:start position:0% +you might worry well this thing here has +to fall fast enough to get rid of that n + + align:start position:0% +to fall fast enough to get rid of that n + + + align:start position:0% +to fall fast enough to get rid of that n +factorial so write this thing out this + + align:start position:0% +factorial so write this thing out this + + + align:start position:0% +factorial so write this thing out this +one as an infinite series of terms from + + align:start position:0% +one as an infinite series of terms from + + + align:start position:0% +one as an infinite series of terms from +0 to Infinity of this same form as this + + align:start position:0% +0 to Infinity of this same form as this + + + align:start position:0% +0 to Infinity of this same form as this +and then what you're left with is the + + align:start position:0% +and then what you're left with is the + + + align:start position:0% +and then what you're left with is the +following thing all the terms from 0 to + + align:start position:0% +following thing all the terms from 0 to + + + align:start position:0% +following thing all the terms from 0 to +n cancel and then you're just left with + + align:start position:0% +n cancel and then you're just left with + + + align:start position:0% +n cancel and then you're just left with +the terms from n plus 1 to + + align:start position:0% + + + + align:start position:0% + +infinity and then you can see that the N + + align:start position:0% +infinity and then you can see that the N + + + align:start position:0% +infinity and then you can see that the N +factorial is being tamed by another + + align:start position:0% +factorial is being tamed by another + + + align:start position:0% +factorial is being tamed by another +factorial growth which is always of a + + align:start position:0% +factorial growth which is always of a + + + align:start position:0% +factorial growth which is always of a +greater power n plus one + + align:start position:0% +greater power n plus one + + + align:start position:0% +greater power n plus one +okay so this is number less than one and + + align:start position:0% +okay so this is number less than one and + + + align:start position:0% +okay so this is number less than one and +this thing here beta Alpha over 2 pi * + + align:start position:0% +this thing here beta Alpha over 2 pi * + + + align:start position:0% +this thing here beta Alpha over 2 pi * +the log is also something that's less + + align:start position:0% +the log is also something that's less + + + align:start position:0% +the log is also something that's less +than one it's a it's exactly the thing + + align:start position:0% +than one it's a it's exactly the thing + + + align:start position:0% +than one it's a it's exactly the thing +that you sum up when you're running the + + align:start position:0% +that you sum up when you're running the + + + align:start position:0% +that you sum up when you're running the +coupling so this is a convergent + + align:start position:0% + + + + align:start position:0% + +series and + + align:start position:0% +series and + + + align:start position:0% +series and +it's basically the physics of it is we + + align:start position:0% +it's basically the physics of it is we + + + align:start position:0% +it's basically the physics of it is we +had this Mass + + align:start position:0% +had this Mass + + + align:start position:0% +had this Mass +that didn't have a renormalon but it had + + align:start position:0% +that didn't have a renormalon but it had + + + align:start position:0% +that didn't have a renormalon but it had +an arbitrary scale and what the + + align:start position:0% +an arbitrary scale and what the + + + align:start position:0% +an arbitrary scale and what the +renormalization group allows us to do is + + align:start position:0% +renormalization group allows us to do is + + + align:start position:0% +renormalization group allows us to do is +move to another scale when we move to + + align:start position:0% +move to another scale when we move to + + + align:start position:0% +move to another scale when we move to +another scale it better be that we don't + + align:start position:0% +another scale it better be that we don't + + + align:start position:0% +another scale it better be that we don't +reintroduce the ralon and the fact that + + align:start position:0% +reintroduce the ralon and the fact that + + + align:start position:0% +reintroduce the ralon and the fact that +I can write this as a convergence series + + align:start position:0% +I can write this as a convergence series + + + align:start position:0% +I can write this as a convergence series +shows very explicitly that I'm not + + align:start position:0% +shows very explicitly that I'm not + + + align:start position:0% +shows very explicitly that I'm not +having that problem in the difference + + align:start position:0% +having that problem in the difference + + + align:start position:0% +having that problem in the difference +between these + + align:start position:0% + + + + align:start position:0% + +two so it's re normalized + + align:start position:0% +two so it's re normalized + + + align:start position:0% +two so it's re normalized +free and it remains normal on free when + + align:start position:0% +free and it remains normal on free when + + + align:start position:0% +free and it remains normal on free when +we change the + + align:start position:0% +we change the + + + align:start position:0% +we change the +scale and we can sum up these logarithms + + align:start position:0% +scale and we can sum up these logarithms + + + align:start position:0% +scale and we can sum up these logarithms +that have to do with changing the + + align:start position:0% + + + + align:start position:0% + +scale so if you were why would you care + + align:start position:0% +scale so if you were why would you care + + + align:start position:0% +scale so if you were why would you care +about that well imagine that you extract + + align:start position:0% +about that well imagine that you extract + + + align:start position:0% +about that well imagine that you extract +this ma Mass from some B physics so you + + align:start position:0% +this ma Mass from some B physics so you + + + align:start position:0% +this ma Mass from some B physics so you +take an R that's of order of GV and then + + align:start position:0% +take an R that's of order of GV and then + + + align:start position:0% +take an R that's of order of GV and then +you say well that's a very precise + + align:start position:0% +you say well that's a very precise + + + align:start position:0% +you say well that's a very precise +number but how do I use it for say LHC + + align:start position:0% +number but how do I use it for say LHC + + + align:start position:0% +number but how do I use it for say LHC +phenomenology well if I want to connect + + align:start position:0% +phenomenology well if I want to connect + + + align:start position:0% +phenomenology well if I want to connect +it to LHC phenomenology I probably want + + align:start position:0% +it to LHC phenomenology I probably want + + + align:start position:0% +it to LHC phenomenology I probably want +to convert to the msar + + align:start position:0% +to convert to the msar + + + align:start position:0% +to convert to the msar +scheme because LC is high energy maybe + + align:start position:0% +scheme because LC is high energy maybe + + + align:start position:0% +scheme because LC is high energy maybe +I'm doing higs to BB bar BB bar very + + align:start position:0% +I'm doing higs to BB bar BB bar very + + + align:start position:0% +I'm doing higs to BB bar BB bar very +energetic so we want to use the MS + + align:start position:0% +energetic so we want to use the MS + + + align:start position:0% +energetic so we want to use the MS +scheme but I've got this mass at a very + + align:start position:0% +scheme but I've got this mass at a very + + + align:start position:0% +scheme but I've got this mass at a very +low scale what you would want to do is + + align:start position:0% +low scale what you would want to do is + + + align:start position:0% +low scale what you would want to do is +you'd want to use the renormalization + + align:start position:0% +you'd want to use the renormalization + + + align:start position:0% +you'd want to use the renormalization +group run it up to the mass scale MB + + align:start position:0% +group run it up to the mass scale MB + + + align:start position:0% +group run it up to the mass scale MB +match switch schemes from this scheme + + align:start position:0% +match switch schemes from this scheme + + + align:start position:0% +match switch schemes from this scheme +there you extracted the mass to msar + + align:start position:0% +there you extracted the mass to msar + + + align:start position:0% +there you extracted the mass to msar +you'd get a correspondingly precise + + align:start position:0% +you'd get a correspondingly precise + + + align:start position:0% +you'd get a correspondingly precise +value of msar because the series between + + align:start position:0% +value of msar because the series between + + + align:start position:0% +value of msar because the series between +this mass and the msar mass is again at + + align:start position:0% +this mass and the msar mass is again at + + + align:start position:0% +this mass and the msar mass is again at +R normal on free series and then you + + align:start position:0% +R normal on free series and then you + + + align:start position:0% +R normal on free series and then you +could take that mass at the MB scale run + + align:start position:0% +could take that mass at the MB scale run + + + align:start position:0% +could take that mass at the MB scale run +it up to say the Hig scale and use it + + align:start position:0% +it up to say the Hig scale and use it + + + align:start position:0% +it up to say the Hig scale and use it +for + + align:start position:0% +for + + + align:start position:0% +for +phenomenology so you always want to be + + align:start position:0% +phenomenology so you always want to be + + + align:start position:0% +phenomenology so you always want to be +able to go back and forth between + + align:start position:0% +able to go back and forth between + + + align:start position:0% +able to go back and forth between +schemes and if different schemes have + + align:start position:0% +schemes and if different schemes have + + + align:start position:0% +schemes and if different schemes have +different scales Associated to them then + + align:start position:0% +different scales Associated to them then + + + align:start position:0% +different scales Associated to them then +you need the renormalization group to in + + align:start position:0% +you need the renormalization group to in + + + align:start position:0% +you need the renormalization group to in +order to put them at the same scale when + + align:start position:0% +order to put them at the same scale when + + + align:start position:0% +order to put them at the same scale when +where you want to do the conversion + + align:start position:0% +where you want to do the conversion + + + align:start position:0% +where you want to do the conversion +okay so that's why being able to sum up + + align:start position:0% +okay so that's why being able to sum up + + + align:start position:0% +okay so that's why being able to sum up +these logarithms without reintroducing + + align:start position:0% +these logarithms without reintroducing + + + align:start position:0% +these logarithms without reintroducing +any ralon problems is is + + align:start position:0% + + + + align:start position:0% + +important and in general if you were to + + align:start position:0% +important and in general if you were to + + + align:start position:0% +important and in general if you were to +try to do this with + + align:start position:0% +try to do this with + + + align:start position:0% +try to do this with +msar um it wouldn't work + + align:start position:0% + + + + align:start position:0% + +uh you don't really have a way of + + align:start position:0% +uh you don't really have a way of + + + align:start position:0% +uh you don't really have a way of +treating the normal on in m in the msar + + align:start position:0% +treating the normal on in m in the msar + + + align:start position:0% +treating the normal on in m in the msar +scheme when you're talking about physics + + align:start position:0% +scheme when you're talking about physics + + + align:start position:0% +scheme when you're talking about physics +below the mass of the + + align:start position:0% + + + + align:start position:0% + +particle okay so we can generalize this + + align:start position:0% +particle okay so we can generalize this + + + align:start position:0% +particle okay so we can generalize this +little discussion here which was a fixed + + align:start position:0% +little discussion here which was a fixed + + + align:start position:0% +little discussion here which was a fixed +order leading log discussion and I can + + align:start position:0% +order leading log discussion and I can + + + align:start position:0% +order leading log discussion and I can +write down for you just how what would + + align:start position:0% +write down for you just how what would + + + align:start position:0% +write down for you just how what would +happen if I were to formally integrate + + align:start position:0% +happen if I were to formally integrate + + + align:start position:0% +happen if I were to formally integrate +this integral here without making any + + align:start position:0% +this integral here without making any + + + align:start position:0% +this integral here without making any +expansion in alpha + + align:start position:0% +expansion in alpha + + + align:start position:0% +expansion in alpha +s + + align:start position:0% + + + + align:start position:0% + +Okay so + + align:start position:0% + + + + align:start position:0% + +so Express gamma R of t as an infinite + + align:start position:0% +so Express gamma R of t as an infinite + + + align:start position:0% +so Express gamma R of t as an infinite +Series in it's an infinite Series in + + align:start position:0% +Series in it's an infinite Series in + + + align:start position:0% +Series in it's an infinite Series in +alpha s that means it's an infinite + + align:start position:0% +alpha s that means it's an infinite + + + align:start position:0% +alpha s that means it's an infinite +Series in one over T we had an + + align:start position:0% +Series in one over T we had an + + + align:start position:0% +Series in one over T we had an +expression for this capital G of T last + + align:start position:0% +expression for this capital G of T last + + + align:start position:0% +expression for this capital G of T last +time which again was a infinite series + + align:start position:0% +time which again was a infinite series + + + align:start position:0% +time which again was a infinite series +just plug in those infinite series do + + align:start position:0% +just plug in those infinite series do + + + align:start position:0% +just plug in those infinite series do +all the integrals they all turned out to + + align:start position:0% +all the integrals they all turned out to + + + align:start position:0% +all the integrals they all turned out to +be incomplete gamma + + align:start position:0% +be incomplete gamma + + + align:start position:0% +be incomplete gamma +functions okay + + align:start position:0% + + + + align:start position:0% + +so we can make write down a formula an + + align:start position:0% +so we can make write down a formula an + + + align:start position:0% +so we can make write down a formula an +all order generalization of that result + + align:start position:0% +all order generalization of that result + + + align:start position:0% +all order generalization of that result +just to see what happens at higher + + align:start position:0% +just to see what happens at higher + + + align:start position:0% +just to see what happens at higher +orders so basically we'd have something + + align:start position:0% + + + + align:start position:0% + +like if I look back at what G of T was + + align:start position:0% +like if I look back at what G of T was + + + align:start position:0% +like if I look back at what G of T was +we'd have something like this and then + + align:start position:0% +we'd have something like this and then + + + align:start position:0% +we'd have something like this and then +all the rest of the terms we can expand + + align:start position:0% +all the rest of the terms we can expand + + + align:start position:0% +all the rest of the terms we can expand +out in a + + align:start position:0% + + + + align:start position:0% + +inverse tailor tailor Series in one over + + align:start position:0% +inverse tailor tailor Series in one over + + + align:start position:0% +inverse tailor tailor Series in one over +t Okay so just there's two terms in G of + + align:start position:0% +t Okay so just there's two terms in G of + + + align:start position:0% +t Okay so just there's two terms in G of +T why I want to keep in the exponential + + align:start position:0% +T why I want to keep in the exponential + + + align:start position:0% +T why I want to keep in the exponential +and then the rest of them I can expand + + align:start position:0% +and then the rest of them I can expand + + + align:start position:0% +and then the rest of them I can expand +out and combine with these terms and + + align:start position:0% +out and combine with these terms and + + + align:start position:0% +out and combine with these terms and +that just gives me some series and I can + + align:start position:0% +that just gives me some series and I can + + + align:start position:0% +that just gives me some series and I can +do these + + align:start position:0% + + + + align:start position:0% + +integrals + + align:start position:0% + + + + align:start position:0% + +so writing the integrand + + align:start position:0% + + + + align:start position:0% + +out we can just establish some notation + + align:start position:0% +out we can just establish some notation + + + align:start position:0% +out we can just establish some notation +for + + align:start position:0% + + + + align:start position:0% + +it for that infinite series of one over + + align:start position:0% +it for that infinite series of one over + + + align:start position:0% +it for that infinite series of one over +T's and we'll just call the coefficients + + align:start position:0% + + + + align:start position:0% + +SJ there's a one overt + + align:start position:0% + + + + align:start position:0% + +there's + + align:start position:0% + + + + align:start position:0% + +the so this gamma bar starts as a one + + align:start position:0% +the so this gamma bar starts as a one + + + align:start position:0% +the so this gamma bar starts as a one +overt so really should so that there's a + + align:start position:0% +overt so really should so that there's a + + + align:start position:0% +overt so really should so that there's a +one t + + align:start position:0% +one t + + + align:start position:0% +one t +here that's where this one overt came + + align:start position:0% +here that's where this one overt came + + + align:start position:0% +here that's where this one overt came +from so then integrate that and that + + align:start position:0% +from so then integrate that and that + + + align:start position:0% +from so then integrate that and that +gives us a generalization of this + + align:start position:0% +gives us a generalization of this + + + align:start position:0% +gives us a generalization of this +formula + + align:start position:0% +formula + + + align:start position:0% +formula +here where we say that M of + + align:start position:0% +here where we say that M of + + + align:start position:0% +here where we say that M of +R1 minus m of r0 which we work where we + + align:start position:0% +R1 minus m of r0 which we work where we + + + align:start position:0% +R1 minus m of r0 which we work where we +work at some order in the + + align:start position:0% +work at some order in the + + + align:start position:0% +work at some order in the +resummation which you would say is n the + + align:start position:0% +resummation which you would say is n the + + + align:start position:0% +resummation which you would say is n the +k l so you have leading log next leading + + align:start position:0% +k l so you have leading log next leading + + + align:start position:0% +k l so you have leading log next leading +log next to next leading log and then + + align:start position:0% +log next to next leading log and then + + + align:start position:0% +log next to next leading log and then +and when you have n when you have K of + + align:start position:0% +and when you have n when you have K of + + + align:start position:0% +and when you have n when you have K of +them you say NK + + align:start position:0% +them you say NK + + + align:start position:0% +them you say NK +L and the solution of that + + align:start position:0% +L and the solution of that + + + align:start position:0% +L and the solution of that +equation would be the Cod or Lambda qcd + + align:start position:0% + + + + align:start position:0% + +and then this + + align:start position:0% + + + + align:start position:0% + +series and instead of just the zero + + align:start position:0% +series and instead of just the zero + + + align:start position:0% +series and instead of just the zero +incomplete gamma function we get some + + align:start position:0% +incomplete gamma function we get some + + + align:start position:0% +incomplete gamma function we get some +slightly different one but it's got the + + align:start position:0% +slightly different one but it's got the + + + align:start position:0% +slightly different one but it's got the +same kind of structure where we get the + + align:start position:0% +same kind of structure where we get the + + + align:start position:0% +same kind of structure where we get the +difference of gamma functions + + align:start position:0% + + + + align:start position:0% + +and these s's are just whatever you get + + align:start position:0% +and these s's are just whatever you get + + + align:start position:0% +and these s's are just whatever you get +from the anous dimension + + align:start position:0% +from the anous dimension + + + align:start position:0% +from the anous dimension +so kind of a simple + + align:start position:0% + + + + align:start position:0% + +notation ET so they're just some + + align:start position:0% +notation ET so they're just some + + + align:start position:0% +notation ET so they're just some +combination of numbers and the twiddles + + align:start position:0% +combination of numbers and the twiddles + + + align:start position:0% +combination of numbers and the twiddles +here is just my short hand + + align:start position:0% +here is just my short hand + + + align:start position:0% +here is just my short hand +for accounting for a fact that there's + + align:start position:0% +for accounting for a fact that there's + + + align:start position:0% +for accounting for a fact that there's +some beta knots floating + + align:start position:0% +some beta knots floating + + + align:start position:0% +some beta knots floating +around okay so this is just + + align:start position:0% + + + + align:start position:0% + +algebra and these B1 hats and B2 hats + + align:start position:0% +algebra and these B1 hats and B2 hats + + + align:start position:0% +algebra and these B1 hats and B2 hats +were things that showed up in the beta + + align:start position:0% +were things that showed up in the beta + + + align:start position:0% +were things that showed up in the beta +function of qcd which we also talked + + align:start position:0% +function of qcd which we also talked + + + align:start position:0% +function of qcd which we also talked +talked about last time so so we defined + + align:start position:0% +talked about last time so so we defined + + + align:start position:0% +talked about last time so so we defined +those last time the B1 hat and B2 hat + + align:start position:0% +those last time the B1 hat and B2 hat + + + align:start position:0% +those last time the B1 hat and B2 hat +were just combinations of the beta beta + + align:start position:0% +were just combinations of the beta beta + + + align:start position:0% +were just combinations of the beta beta +1 and beta + + align:start position:0% +1 and beta + + + align:start position:0% +1 and beta +2 and beta + + align:start position:0% +2 and beta + + + align:start position:0% +2 and beta +0o okay so these are some numbers that + + align:start position:0% +0o okay so these are some numbers that + + + align:start position:0% +0o okay so these are some numbers that +you can calculate given the enous + + align:start position:0% +you can calculate given the enous + + + align:start position:0% +you can calculate given the enous +dimensions given those numbers you can + + align:start position:0% +dimensions given those numbers you can + + + align:start position:0% +dimensions given those numbers you can +plug it into this formula and then you + + align:start position:0% +plug it into this formula and then you + + + align:start position:0% +plug it into this formula and then you +have + + align:start position:0% +have + + + align:start position:0% +have +a generalization of the previous result + + align:start position:0% +a generalization of the previous result + + + align:start position:0% +a generalization of the previous result +so whatever order you know the enal + + align:start position:0% +so whatever order you know the enal + + + align:start position:0% +so whatever order you know the enal +dimension to you can use that solution + + align:start position:0% +dimension to you can use that solution + + + align:start position:0% +dimension to you can use that solution +and we'll use it a little later when I + + align:start position:0% +and we'll use it a little later when I + + + align:start position:0% +and we'll use it a little later when I +talk about some + + align:start position:0% + + + + align:start position:0% + +numbers all right so any questions so + + align:start position:0% +numbers all right so any questions so + + + align:start position:0% +numbers all right so any questions so +far + + align:start position:0% + + + + align:start position:0% + +there's a similar thing for msar Mass if + + align:start position:0% +there's a similar thing for msar Mass if + + + align:start position:0% +there's a similar thing for msar Mass if +you were summing logs of the MS bar Mass + + align:start position:0% +you were summing logs of the MS bar Mass + + + align:start position:0% +you were summing logs of the MS bar Mass +there's an all orders formula you can + + align:start position:0% +there's an all orders formula you can + + + align:start position:0% +there's an all orders formula you can +write down and use once you know the + + align:start position:0% +write down and use once you know the + + + align:start position:0% +write down and use once you know the +normal dimensions you could find it in + + align:start position:0% +normal dimensions you could find it in + + + align:start position:0% +normal dimensions you could find it in +the particle Data Book I + + align:start position:0% +the particle Data Book I + + + align:start position:0% +the particle Data Book I +think all right + + align:start position:0% +think all right + + + align:start position:0% +think all right +so just coming back to this comment + + align:start position:0% +so just coming back to this comment + + + align:start position:0% +so just coming back to this comment +about the fact that the anomalous + + align:start position:0% +about the fact that the anomalous + + + align:start position:0% +about the fact that the anomalous +Dimension is R normal on + + align:start position:0% + + + + align:start position:0% + +free so the fact the fact that the + + align:start position:0% +free so the fact the fact that the + + + align:start position:0% +free so the fact the fact that the +solution here was romal on free that the + + align:start position:0% +solution here was romal on free that the + + + align:start position:0% +solution here was romal on free that the +difference here was aalon free was + + align:start position:0% +difference here was aalon free was + + + align:start position:0% +difference here was aalon free was +because there was no ralon on the right + + align:start position:0% +because there was no ralon on the right + + + align:start position:0% +because there was no ralon on the right +hand side here and that the anomalous + + align:start position:0% +hand side here and that the anomalous + + + align:start position:0% +hand side here and that the anomalous +Dimension was ralon + + align:start position:0% +Dimension was ralon + + + align:start position:0% +Dimension was ralon +free and it was constructed from + + align:start position:0% +free and it was constructed from + + + align:start position:0% +free and it was constructed from +something that had a + + align:start position:0% +something that had a + + + align:start position:0% +something that had a +renormalon which is this Delta + + align:start position:0% +renormalon which is this Delta + + + align:start position:0% +renormalon which is this Delta +M but it was a derivative of that Delta + + align:start position:0% +M but it was a derivative of that Delta + + + align:start position:0% +M but it was a derivative of that Delta +M and + + align:start position:0% +M and + + + align:start position:0% +M and +so the derivative kills the re normal + + align:start position:0% +so the derivative kills the re normal + + + align:start position:0% +so the derivative kills the re normal +on so this thing is + + align:start position:0% + + + + align:start position:0% + +free of the delta to M of order Lambda + + align:start position:0% +free of the delta to M of order Lambda + + + align:start position:0% +free of the delta to M of order Lambda +qcd + + align:start position:0% +qcd + + + align:start position:0% +qcd +renormalon because that renormalon is a + + align:start position:0% +renormalon because that renormalon is a + + + align:start position:0% +renormalon because that renormalon is a +constant and when you take the + + align:start position:0% +constant and when you take the + + + align:start position:0% +constant and when you take the +derivative you kill the constant that's + + align:start position:0% +derivative you kill the constant that's + + + align:start position:0% +derivative you kill the constant that's +how you can think of + + align:start position:0% +how you can think of + + + align:start position:0% +how you can think of +it if you start writing out the gamma + + align:start position:0% +it if you start writing out the gamma + + + align:start position:0% +it if you start writing out the gamma +functions then you see that it looks + + align:start position:0% +functions then you see that it looks + + + align:start position:0% +functions then you see that it looks +like you're finding the r normal on but + + align:start position:0% +like you're finding the r normal on but + + + align:start position:0% +like you're finding the r normal on but +then there's some differences that show + + align:start position:0% +then there's some differences that show + + + align:start position:0% +then there's some differences that show +up and and cancel it off so the way that + + align:start position:0% +up and and cancel it off so the way that + + + align:start position:0% +up and and cancel it off so the way that +that + + align:start position:0% +that + + + align:start position:0% +that +works it's kind of like this where you + + align:start position:0% +works it's kind of like this where you + + + align:start position:0% +works it's kind of like this where you +see sort of think that you have the re + + align:start position:0% +see sort of think that you have the re + + + align:start position:0% +see sort of think that you have the re +normal on but then you realize there's + + align:start position:0% +normal on but then you realize there's + + + align:start position:0% +normal on but then you realize there's +another term in cancels it + + align:start position:0% + + + + align:start position:0% + +off so if + + align:start position:0% +off so if + + + align:start position:0% +off so if +we if we look back at our formula for + + align:start position:0% +we if we look back at our formula for + + + align:start position:0% +we if we look back at our formula for +Delta M this had an infinite series of + + align:start position:0% +Delta M this had an infinite series of + + + align:start position:0% +Delta M this had an infinite series of +A's so was like a sum over some a ends + + align:start position:0% +A's so was like a sum over some a ends + + + align:start position:0% +A's so was like a sum over some a ends +and some Alpha to the N some other + + align:start position:0% +and some Alpha to the N some other + + + align:start position:0% +and some Alpha to the N some other +factors and these gamas are just related + + align:start position:0% +factors and these gamas are just related + + + align:start position:0% +factors and these gamas are just related +to the + + align:start position:0% + + + + align:start position:0% + +A's but they're not just related to the + + align:start position:0% +A's but they're not just related to the + + + align:start position:0% +A's but they're not just related to the +A's they're also factors of the beta + + align:start position:0% +A's they're also factors of the beta + + + align:start position:0% +A's they're also factors of the beta +function that come + + align:start position:0% +function that come + + + align:start position:0% +function that come +in + + align:start position:0% +in + + + align:start position:0% +in +so just to give you an + + align:start position:0% + + + + align:start position:0% + +idea so once you know the scheme + + align:start position:0% +idea so once you know the scheme + + + align:start position:0% +idea so once you know the scheme +conversion to the scheme + + align:start position:0% +conversion to the scheme + + + align:start position:0% +conversion to the scheme +then you know the anomalous + + align:start position:0% + + + + align:start position:0% + +Dimension and if you look at this series + + align:start position:0% +Dimension and if you look at this series + + + align:start position:0% +Dimension and if you look at this series +and you think about whether the series + + align:start position:0% +and you think about whether the series + + + align:start position:0% +and you think about whether the series +for the Nal Dimension is convergent or + + align:start position:0% +for the Nal Dimension is convergent or + + + align:start position:0% +for the Nal Dimension is convergent or +ASM + + align:start position:0% + + + + align:start position:0% + +totic you can sort of identify the + + align:start position:0% +totic you can sort of identify the + + + align:start position:0% +totic you can sort of identify the +pattern of how these coefficients look + + align:start position:0% +pattern of how these coefficients look + + + align:start position:0% +pattern of how these coefficients look +and basically if you for example look at + + align:start position:0% +and basically if you for example look at + + + align:start position:0% +and basically if you for example look at +the bubble sum this a n + one would be + + align:start position:0% +the bubble sum this a n + one would be + + + align:start position:0% +the bubble sum this a n + one would be +something that has an N Factor factorial + + align:start position:0% +something that has an N Factor factorial + + + align:start position:0% +something that has an N Factor factorial +2 Beta KN to the n + + + align:start position:0% +2 Beta KN to the n + + + + align:start position:0% +2 Beta KN to the n + +one oh sorry to the N + + align:start position:0% +one oh sorry to the N + + + align:start position:0% +one oh sorry to the N +growth and then this thing here is n + + align:start position:0% +growth and then this thing here is n + + + align:start position:0% +growth and then this thing here is n +minus1 + + align:start position:0% +minus1 + + + align:start position:0% +minus1 +factorial to Beta to the N minus + + align:start position:0% +factorial to Beta to the N minus + + + align:start position:0% +factorial to Beta to the N minus +one and then there's this exra 2N beta + + align:start position:0% +one and then there's this exra 2N beta + + + align:start position:0% +one and then there's this exra 2N beta +KN that multiplies it and you can see + + align:start position:0% +KN that multiplies it and you can see + + + align:start position:0% +KN that multiplies it and you can see +that there there's an exact cancellation + + align:start position:0% +that there there's an exact cancellation + + + align:start position:0% +that there there's an exact cancellation +so that's how the bubble sum you know + + align:start position:0% +so that's how the bubble sum you know + + + align:start position:0% +so that's how the bubble sum you know +one way of probing the normalan is just + + align:start position:0% +one way of probing the normalan is just + + + align:start position:0% +one way of probing the normalan is just +to look at the bubble sum and the bubble + + align:start position:0% +to look at the bubble sum and the bubble + + + align:start position:0% +to look at the bubble sum and the bubble +sum gave us a particular value of these + + align:start position:0% +sum gave us a particular value of these + + + align:start position:0% +sum gave us a particular value of these +A's and you can see that the bubble sum + + align:start position:0% +A's and you can see that the bubble sum + + + align:start position:0% +A's and you can see that the bubble sum +R normalan is canceling out between the + + align:start position:0% +R normalan is canceling out between the + + + align:start position:0% +R normalan is canceling out between the +terms + + align:start position:0% + + + + align:start position:0% + +here okay so that's just a expression of + + align:start position:0% +here okay so that's just a expression of + + + align:start position:0% +here okay so that's just a expression of +what I said over here that's kind of + + align:start position:0% +what I said over here that's kind of + + + align:start position:0% +what I said over here that's kind of +more definite expression of the fact + + align:start position:0% +more definite expression of the fact + + + align:start position:0% +more definite expression of the fact +that this thing is actually free of the + + align:start position:0% +that this thing is actually free of the + + + align:start position:0% +that this thing is actually free of the +normal on + + align:start position:0% + + + + align:start position:0% + +so I'm going to put this aside for a + + align:start position:0% +so I'm going to put this aside for a + + + align:start position:0% +so I'm going to put this aside for a +minute and we'll come back and use this + + align:start position:0% +minute and we'll come back and use this + + + align:start position:0% +minute and we'll come back and use this +formula a little later in today's + + align:start position:0% +formula a little later in today's + + + align:start position:0% +formula a little later in today's +lecture um and I want to so there's sort + + align:start position:0% +lecture um and I want to so there's sort + + + align:start position:0% +lecture um and I want to so there's sort +of two ways that you can use this + + align:start position:0% +of two ways that you can use this + + + align:start position:0% +of two ways that you can use this +technology you can use it as a means of + + align:start position:0% +technology you can use it as a means of + + + align:start position:0% +technology you can use it as a means of +doing what I said of connecting masses + + align:start position:0% +doing what I said of connecting masses + + + align:start position:0% +doing what I said of connecting masses +at different scales and doing + + align:start position:0% +at different scales and doing + + + align:start position:0% +at different scales and doing +phenomenology and we'll come back to + + align:start position:0% +phenomenology and we'll come back to + + + align:start position:0% +phenomenology and we'll come back to +that a little bit later but you could + + align:start position:0% +that a little bit later but you could + + + align:start position:0% +that a little bit later but you could +also use it as a probe of the renormalon + + align:start position:0% +also use it as a probe of the renormalon + + + align:start position:0% +also use it as a probe of the renormalon +so one thing that you might complain + + align:start position:0% +so one thing that you might complain + + + align:start position:0% +so one thing that you might complain +about with the bubble sum is it's just + + align:start position:0% +about with the bubble sum is it's just + + + align:start position:0% +about with the bubble sum is it's just +some arbitrarily chosen way of probing + + align:start position:0% +some arbitrarily chosen way of probing + + + align:start position:0% +some arbitrarily chosen way of probing +the renormalon and maybe there's some + + align:start position:0% +the renormalon and maybe there's some + + + align:start position:0% +the renormalon and maybe there's some +problem where you don't have like Fons + + align:start position:0% +problem where you don't have like Fons + + + align:start position:0% +problem where you don't have like Fons +around maybe you only have gluons and + + align:start position:0% +around maybe you only have gluons and + + + align:start position:0% +around maybe you only have gluons and +there could still be a renormalon in + + align:start position:0% +there could still be a renormalon in + + + align:start position:0% +there could still be a renormalon in +those problems so how would you deal + + align:start position:0% +those problems so how would you deal + + + align:start position:0% +those problems so how would you deal +with that if you didn't have the light + + align:start position:0% +with that if you didn't have the light + + + align:start position:0% +with that if you didn't have the light +quarks available to make up this bubble + + align:start position:0% +quarks available to make up this bubble + + + align:start position:0% +quarks available to make up this bubble +sum or maybe there's some renormalon + + align:start position:0% +sum or maybe there's some renormalon + + + align:start position:0% +sum or maybe there's some renormalon +that just so happens you don't see it + + align:start position:0% +that just so happens you don't see it + + + align:start position:0% +that just so happens you don't see it +with the quirks there's no guarantee of + + align:start position:0% +with the quirks there's no guarantee of + + + align:start position:0% +with the quirks there's no guarantee of +that so you'd like to have some other + + align:start position:0% +that so you'd like to have some other + + + align:start position:0% +that so you'd like to have some other +mechanism for looking for renormalons + + align:start position:0% +mechanism for looking for renormalons + + + align:start position:0% +mechanism for looking for renormalons +and you can actually use the + + align:start position:0% +and you can actually use the + + + align:start position:0% +and you can actually use the +renormalization group to do that which + + align:start position:0% +renormalization group to do that which + + + align:start position:0% +renormalization group to do that which +is kind of interesting so I'll show you + + align:start position:0% +is kind of interesting so I'll show you + + + align:start position:0% +is kind of interesting so I'll show you +how that + + align:start position:0% + + + + align:start position:0% + +works it also makes it nice thing about + + align:start position:0% +works it also makes it nice thing about + + + align:start position:0% +works it also makes it nice thing about +this is it also makes it clear how the + + align:start position:0% +this is it also makes it clear how the + + + align:start position:0% +this is it also makes it clear how the +renormalon relates to the landow pole so + + align:start position:0% +renormalon relates to the landow pole so + + + align:start position:0% +renormalon relates to the landow pole so +we'll see that as + + align:start position:0% + + + + align:start position:0% + +well so take our solution for the RG + + align:start position:0% +well so take our solution for the RG + + + align:start position:0% +well so take our solution for the RG +we could write in terms of this + + align:start position:0% + + + + align:start position:0% + +intergral and let's consider what this + + align:start position:0% +intergral and let's consider what this + + + align:start position:0% +intergral and let's consider what this +integral actually is doing in the + + align:start position:0% +integral actually is doing in the + + + align:start position:0% +integral actually is doing in the +complex T + + align:start position:0% +complex T + + + align:start position:0% +complex T +plane + + align:start position:0% + + + + align:start position:0% + +so the t's are + + align:start position:0% + + + + align:start position:0% + +negative and so they look like this the + + align:start position:0% +negative and so they look like this the + + + align:start position:0% +negative and so they look like this the +land + + align:start position:0% +land + + + align:start position:0% +land +Pole where the coupling blows up is + + align:start position:0% +Pole where the coupling blows up is + + + align:start position:0% +Pole where the coupling blows up is +where the T goes to zero so the land out + + align:start position:0% +where the T goes to zero so the land out + + + align:start position:0% +where the T goes to zero so the land out +pole is at the + + align:start position:0% + + + + align:start position:0% + +origin okay so this is what the complex + + align:start position:0% +origin okay so this is what the complex + + + align:start position:0% +origin okay so this is what the complex +T plane looks + + align:start position:0% + + + + align:start position:0% + +like and what we're doing when we do the + + align:start position:0% +like and what we're doing when we do the + + + align:start position:0% +like and what we're doing when we do the +integral is we're just doing an integral + + align:start position:0% +integral is we're just doing an integral + + + align:start position:0% +integral is we're just doing an integral +over that little range here right so + + align:start position:0% +over that little range here right so + + + align:start position:0% +over that little range here right so +we're far away from the L up hole and + + align:start position:0% +we're far away from the L up hole and + + + align:start position:0% +we're far away from the L up hole and +that's why everything was nicely + + align:start position:0% +that's why everything was nicely + + + align:start position:0% +that's why everything was nicely +convergent and you could connect one + + align:start position:0% +convergent and you could connect one + + + align:start position:0% +convergent and you could connect one +Mass to + + align:start position:0% +Mass to + + + align:start position:0% +Mass to +another but you you could ask what + + align:start position:0% +another but you you could ask what + + + align:start position:0% +another but you you could ask what +happens if I take this t0 and I move it + + align:start position:0% +happens if I take this t0 and I move it + + + align:start position:0% +happens if I take this t0 and I move it +somewhere else in this in this picture + + align:start position:0% +somewhere else in this in this picture + + + align:start position:0% +somewhere else in this in this picture +and that's what we're going to + + align:start position:0% +and that's what we're going to + + + align:start position:0% +and that's what we're going to +do so let's consider the limit where r0 + + align:start position:0% +do so let's consider the limit where r0 + + + align:start position:0% +do so let's consider the limit where r0 +goes to + + align:start position:0% + + + + align:start position:0% + +zero if R goes to zero and you look back + + align:start position:0% +zero if R goes to zero and you look back + + + align:start position:0% +zero if R goes to zero and you look back +at the formula that we had that converts + + align:start position:0% +at the formula that we had that converts + + + align:start position:0% +at the formula that we had that converts +between the msar mass and this m of + + align:start position:0% +between the msar mass and this m of + + + align:start position:0% +between the msar mass and this m of +R you'll see that M of + + align:start position:0% +R you'll see that M of + + + align:start position:0% +R you'll see that M of +r0 goes to M Pole + + align:start position:0% + + + + align:start position:0% + +because we had a power of R times a + + align:start position:0% +because we had a power of R times a + + + align:start position:0% +because we had a power of R times a +series of alpha of RS which are just + + align:start position:0% +series of alpha of RS which are just + + + align:start position:0% +series of alpha of RS which are just +logs of R the power always wins and so + + align:start position:0% +logs of R the power always wins and so + + + align:start position:0% +logs of R the power always wins and so +the mass goes to the pole mass and that + + align:start position:0% +the mass goes to the pole mass and that + + + align:start position:0% +the mass goes to the pole mass and that +limit that r0 goes to + + align:start position:0% +limit that r0 goes to + + + align:start position:0% +limit that r0 goes to +zero and if you look at what t0 + + align:start position:0% + + + + align:start position:0% + +is t0 is related to the coupling which I + + align:start position:0% +is t0 is related to the coupling which I + + + align:start position:0% +is t0 is related to the coupling which I +could write in terms of a log of Lambda + + align:start position:0% +could write in terms of a log of Lambda + + + align:start position:0% +could write in terms of a log of Lambda +qcd and t0 is basically in this limit + + align:start position:0% +qcd and t0 is basically in this limit + + + align:start position:0% +qcd and t0 is basically in this limit +going to Plus + + align:start position:0% +going to Plus + + + align:start position:0% +going to Plus +inity so what happens is if I want to + + align:start position:0% +inity so what happens is if I want to + + + align:start position:0% +inity so what happens is if I want to +get back to the pole Mass from one of + + align:start position:0% +get back to the pole Mass from one of + + + align:start position:0% +get back to the pole Mass from one of +these masses I basically have to take + + align:start position:0% +these masses I basically have to take + + + align:start position:0% +these masses I basically have to take +this guy and move out to Infinity which + + align:start position:0% +this guy and move out to Infinity which + + + align:start position:0% +this guy and move out to Infinity which +means I have to make a choice about + + align:start position:0% +means I have to make a choice about + + + align:start position:0% +means I have to make a choice about +going around that Lando Pole + + align:start position:0% + + + + align:start position:0% + +so basically you're taking your rge and + + align:start position:0% +so basically you're taking your rge and + + + align:start position:0% +so basically you're taking your rge and +you're pushing it into a region that's + + align:start position:0% +you're pushing it into a region that's + + + align:start position:0% +you're pushing it into a region that's +where you're no longer completely + + align:start position:0% +where you're no longer completely + + + align:start position:0% +where you're no longer completely +perturbative and that you're forced to + + align:start position:0% +perturbative and that you're forced to + + + align:start position:0% +perturbative and that you're forced to +continue by the L out + + align:start position:0% + + + + align:start position:0% + +Pole now you can actually avoid the land + + align:start position:0% +Pole now you can actually avoid the land + + + align:start position:0% +Pole now you can actually avoid the land +out + + align:start position:0% + + + + align:start position:0% + +pole by going far you know it's true + + align:start position:0% +pole by going far you know it's true + + + align:start position:0% +pole by going far you know it's true +that the series becomes non-perturbative + + align:start position:0% +that the series becomes non-perturbative + + + align:start position:0% +that the series becomes non-perturbative +in this region but you you could go way + + align:start position:0% +in this region but you you could go way + + + align:start position:0% +in this region but you you could go way +up here and come back over there so you + + align:start position:0% +up here and come back over there so you + + + align:start position:0% +up here and come back over there so you +can actually AO you can actually + + align:start position:0% +can actually AO you can actually + + + align:start position:0% +can actually AO you can actually +formally stay in a region in the complex + + align:start position:0% +formally stay in a region in the complex + + + align:start position:0% +formally stay in a region in the complex +plane where your perturbation theory is + + align:start position:0% +plane where your perturbation theory is + + + align:start position:0% +plane where your perturbation theory is +still + + align:start position:0% +still + + + align:start position:0% +still +applicable but you still have to decide + + align:start position:0% +applicable but you still have to decide + + + align:start position:0% +applicable but you still have to decide +which way you go going to go around + + align:start position:0% +which way you go going to go around + + + align:start position:0% +which way you go going to go around +it and so that introduces it an + + align:start position:0% +it and so that introduces it an + + + align:start position:0% +it and so that introduces it an +ambiguity + + align:start position:0% + + + + align:start position:0% + +so doing + + align:start position:0% + + + + align:start position:0% + +that say we go above or + + align:start position:0% + + + + align:start position:0% + +something and if you plug in in this + + align:start position:0% +something and if you plug in in this + + + align:start position:0% +something and if you plug in in this +result the lowest order meeing log + + align:start position:0% + + + + align:start position:0% + +result you get this + + align:start position:0% +result you get this + + + align:start position:0% +result you get this +integral and this integral you know you + + align:start position:0% +integral and this integral you know you + + + align:start position:0% +integral and this integral you know you +have to go around the t equal Z pole + + align:start position:0% +have to go around the t equal Z pole + + + align:start position:0% +have to go around the t equal Z pole +because T1 is + + align:start position:0% +because T1 is + + + align:start position:0% +because T1 is +negative so it turns out that you can + + align:start position:0% +negative so it turns out that you can + + + align:start position:0% +negative so it turns out that you can +actually take this interval and I'm + + align:start position:0% +actually take this interval and I'm + + + align:start position:0% +actually take this interval and I'm +going to leave this for your problem + + align:start position:0% + + + + align:start position:0% + +set and write it in the form of a barel + + align:start position:0% + + + + align:start position:0% + +intergral with an + + align:start position:0% +intergral with an + + + align:start position:0% +intergral with an +exponential that's exactly the Burell + + align:start position:0% +exponential that's exactly the Burell + + + align:start position:0% +exponential that's exactly the Burell +transform + + align:start position:0% +transform + + + align:start position:0% +transform +variable I just change variable from T + + align:start position:0% +variable I just change variable from T + + + align:start position:0% +variable I just change variable from T +to + + align:start position:0% +to + + + align:start position:0% +to +U so I get this + + align:start position:0% +U so I get this + + + align:start position:0% +U so I get this +integral and if you do that what you + + align:start position:0% +integral and if you do that what you + + + align:start position:0% +integral and if you do that what you +find is that F of U is + + align:start position:0% +find is that F of U is + + + align:start position:0% +find is that F of U is +proportional to 1 over uus a + + align:start position:0% +proportional to 1 over uus a + + + align:start position:0% +proportional to 1 over uus a +half what's the L + + align:start position:0% +half what's the L + + + align:start position:0% +half what's the L +zero + + align:start position:0% + + + + align:start position:0% + +yeah okay so you can actually see that + + align:start position:0% +yeah okay so you can actually see that + + + align:start position:0% +yeah okay so you can actually see that +the rge and what was the Lando pole here + + align:start position:0% +the rge and what was the Lando pole here + + + align:start position:0% +the rge and what was the Lando pole here +is effectively in this inter here + + align:start position:0% +is effectively in this inter here + + + align:start position:0% +is effectively in this inter here +becoming this baral pole at U equal a + + align:start position:0% + + + + align:start position:0% + +half and that makes a little more + + align:start position:0% +half and that makes a little more + + + align:start position:0% +half and that makes a little more +clear the fact that these poles are + + align:start position:0% +clear the fact that these poles are + + + align:start position:0% +clear the fact that these poles are +related to the non-perturbative physics + + align:start position:0% +related to the non-perturbative physics + + + align:start position:0% +related to the non-perturbative physics +that's in the coupling in the the + + align:start position:0% +that's in the coupling in the the + + + align:start position:0% +that's in the coupling in the the +infrared + + align:start position:0% +infrared + + + align:start position:0% +infrared +physics so formally this actually allows + + align:start position:0% +physics so formally this actually allows + + + align:start position:0% +physics so formally this actually allows +you to set up a method of trying to find + + align:start position:0% +you to set up a method of trying to find + + + align:start position:0% +you to set up a method of trying to find +the normal on because you can just do + + align:start position:0% +the normal on because you can just do + + + align:start position:0% +the normal on because you can just do +this Contin you can ask given some + + align:start position:0% +this Contin you can ask given some + + + align:start position:0% +this Contin you can ask given some +series if I if I sort of construct this + + align:start position:0% +series if I if I sort of construct this + + + align:start position:0% +series if I if I sort of construct this +thing what if I just I had this attitude + + align:start position:0% +thing what if I just I had this attitude + + + align:start position:0% +thing what if I just I had this attitude +that we want to pick that series to + + align:start position:0% +that we want to pick that series to + + + align:start position:0% +that we want to pick that series to +cancel R normal on now take the attitude + + align:start position:0% +cancel R normal on now take the attitude + + + align:start position:0% +cancel R normal on now take the attitude +what if we didn't know that that series + + align:start position:0% +what if we didn't know that that series + + + align:start position:0% +what if we didn't know that that series +had a r normal on I could still throw it + + align:start position:0% +had a r normal on I could still throw it + + + align:start position:0% +had a r normal on I could still throw it +in make a change of variable to some + + align:start position:0% +in make a change of variable to some + + + align:start position:0% +in make a change of variable to some +Mass if it's a convergent series then + + align:start position:0% +Mass if it's a convergent series then + + + align:start position:0% +Mass if it's a convergent series then +I'm just defining some new mass and I + + align:start position:0% +I'm just defining some new mass and I + + + align:start position:0% +I'm just defining some new mass and I +could go through this technology and it + + align:start position:0% +could go through this technology and it + + + align:start position:0% +could go through this technology and it +would turn it should turn out that if uh + + align:start position:0% +would turn it should turn out that if uh + + + align:start position:0% +would turn it should turn out that if uh +if the series was okay so to speak then + + align:start position:0% +if the series was okay so to speak then + + + align:start position:0% +if the series was okay so to speak then +you wouldn't find this normal + + align:start position:0% +you wouldn't find this normal + + + align:start position:0% +you wouldn't find this normal +on you wouldn't find a a pole + + align:start position:0% +on you wouldn't find a a pole + + + align:start position:0% +on you wouldn't find a a pole +there and that can be I won't go through + + align:start position:0% +there and that can be I won't go through + + + align:start position:0% +there and that can be I won't go through +this in detail because it does it is a + + align:start position:0% +this in detail because it does it is a + + + align:start position:0% +this in detail because it does it is a +bit tricky to + + align:start position:0% +bit tricky to + + + align:start position:0% +bit tricky to +derive but you can derive what's called + + align:start position:0% +derive but you can derive what's called + + + align:start position:0% +derive but you can derive what's called +a sum rule for the renormalon which is + + align:start position:0% +a sum rule for the renormalon which is + + + align:start position:0% +a sum rule for the renormalon which is +another way of probing + + align:start position:0% +another way of probing + + + align:start position:0% +another way of probing +it by basically taking our all order + + align:start position:0% +it by basically taking our all order + + + align:start position:0% +it by basically taking our all order +solution so I took our leading log + + align:start position:0% +solution so I took our leading log + + + align:start position:0% +solution so I took our leading log +solution here + + align:start position:0% +solution here + + + align:start position:0% +solution here +right if I did the same thing with the + + align:start position:0% +right if I did the same thing with the + + + align:start position:0% +right if I did the same thing with the +all orders + + align:start position:0% +all orders + + + align:start position:0% +all orders +solution I could also take the baral + + align:start position:0% +solution I could also take the baral + + + align:start position:0% +solution I could also take the baral +transform of that and that if I do that + + align:start position:0% +transform of that and that if I do that + + + align:start position:0% +transform of that and that if I do that +gives me this thing called a sum rule + + align:start position:0% + + + + align:start position:0% + +so it's just manipulating infinite + + align:start position:0% +so it's just manipulating infinite + + + align:start position:0% +so it's just manipulating infinite +series + + align:start position:0% +series + + + align:start position:0% +series +and Mathematica can sum some of them up + + align:start position:0% +and Mathematica can sum some of them up + + + align:start position:0% +and Mathematica can sum some of them up +for you + + align:start position:0% + + + + align:start position:0% + +so it's just + + align:start position:0% + + + + align:start position:0% + +tedious and what you + + align:start position:0% + + + + align:start position:0% + +find is a + + align:start position:0% +find is a + + + align:start position:0% +find is a +formula for the residue + + align:start position:0% +formula for the residue + + + align:start position:0% +formula for the residue +of the barell + + align:start position:0% +of the barell + + + align:start position:0% +of the barell +pole so let me call that residue + + align:start position:0% + + + + align:start position:0% + +p12 and the the answer is actually + + align:start position:0% +p12 and the the answer is actually + + + align:start position:0% +p12 and the the answer is actually +pretty + + align:start position:0% + + + + align:start position:0% + +simple so these s's were these + + align:start position:0% +simple so these s's were these + + + align:start position:0% +simple so these s's were these +coefficients that were showing up in our + + align:start position:0% +coefficients that were showing up in our + + + align:start position:0% +coefficients that were showing up in our +solution for the all ERS + + align:start position:0% +solution for the all ERS + + + align:start position:0% +solution for the all ERS +rge p12 is a series which will tell me + + align:start position:0% +rge p12 is a series which will tell me + + + align:start position:0% +rge p12 is a series which will tell me +the residue of the + + align:start position:0% +the residue of the + + + align:start position:0% +the residue of the +pole so that means that if p12 is not + + align:start position:0% +pole so that means that if p12 is not + + + align:start position:0% +pole so that means that if p12 is not +equal to + + align:start position:0% +equal to + + + align:start position:0% +equal to +zero then you have a u equals a half + + align:start position:0% + + + + align:start position:0% + +pole and if P of P2 is equal zero + + align:start position:0% +pole and if P of P2 is equal zero + + + align:start position:0% +pole and if P of P2 is equal zero +then you have no U equals a half + + align:start position:0% +then you have no U equals a half + + + align:start position:0% +then you have no U equals a half +Pole now in practice you don't have an + + align:start position:0% +Pole now in practice you don't have an + + + align:start position:0% +Pole now in practice you don't have an +all orders result you only know a not + + align:start position:0% +all orders result you only know a not + + + align:start position:0% +all orders result you only know a not +finite number of these s's so what you + + align:start position:0% +finite number of these s's so what you + + + align:start position:0% +finite number of these s's so what you +actually do is you look at this series + + align:start position:0% +actually do is you look at this series + + + align:start position:0% +actually do is you look at this series +and you try to figure out where it's + + align:start position:0% +and you try to figure out where it's + + + align:start position:0% +and you try to figure out where it's +converging + + align:start position:0% +converging + + + align:start position:0% +converging +to okay but actually even with the + + align:start position:0% +to okay but actually even with the + + + align:start position:0% +to okay but actually even with the +knowledge that we have of the of the + + align:start position:0% +knowledge that we have of the of the + + + align:start position:0% +knowledge that we have of the of the +series for example for the bork Mass you + + align:start position:0% +series for example for the bork Mass you + + + align:start position:0% +series for example for the bork Mass you +can very quickly see that has a u equals + + align:start position:0% +can very quickly see that has a u equals + + + align:start position:0% +can very quickly see that has a u equals +a half pole and you can even do some air + + align:start position:0% +a half pole and you can even do some air + + + align:start position:0% +a half pole and you can even do some air +analysis by varying some things and + + align:start position:0% +analysis by varying some things and + + + align:start position:0% +analysis by varying some things and +you're get some kind of idea of the + + align:start position:0% +you're get some kind of idea of the + + + align:start position:0% +you're get some kind of idea of the +theoretical uncertainty from higher + + align:start position:0% +theoretical uncertainty from higher + + + align:start position:0% +theoretical uncertainty from higher +order terms in the series if you just + + align:start position:0% +order terms in the series if you just + + + align:start position:0% +order terms in the series if you just +formally say take a series that's + + align:start position:0% +formally say take a series that's + + + align:start position:0% +formally say take a series that's +convergent you could calculate if I hand + + align:start position:0% +convergent you could calculate if I hand + + + align:start position:0% +convergent you could calculate if I hand +you a series that's convergent you can + + align:start position:0% +you a series that's convergent you can + + + align:start position:0% +you a series that's convergent you can +calculate all these + + align:start position:0% +calculate all these + + + align:start position:0% +calculate all these +SKS and then you can very easily see + + align:start position:0% +SKS and then you can very easily see + + + align:start position:0% +SKS and then you can very easily see +that actually there's no equals a half + + align:start position:0% +that actually there's no equals a half + + + align:start position:0% +that actually there's no equals a half +pole what happens is all the terms are + + align:start position:0% +pole what happens is all the terms are + + + align:start position:0% +pole what happens is all the terms are +cancelling in this series and you just + + align:start position:0% +cancelling in this series and you just + + + align:start position:0% +cancelling in this series and you just +get + + align:start position:0% +get + + + align:start position:0% +get +zero okay so it's kind of like the + + align:start position:0% +zero okay so it's kind of like the + + + align:start position:0% +zero okay so it's kind of like the +cancellations I was talking about where + + align:start position:0% +cancellations I was talking about where + + + align:start position:0% +cancellations I was talking about where +I was cancelling a pole in the in the + + align:start position:0% +I was cancelling a pole in the in the + + + align:start position:0% +I was cancelling a pole in the in the +anomal dimension but here it's happening + + align:start position:0% +anomal dimension but here it's happening + + + align:start position:0% +anomal dimension but here it's happening +this thing if I have a convergent Series + + align:start position:0% +this thing if I have a convergent Series + + + align:start position:0% +this thing if I have a convergent Series +so this is a way of probing for normal + + align:start position:0% +so this is a way of probing for normal + + + align:start position:0% +so this is a way of probing for normal +on which doesn't rely on the bubble sum + + align:start position:0% +on which doesn't rely on the bubble sum + + + align:start position:0% +on which doesn't rely on the bubble sum +and basically uses the perturbative + + align:start position:0% +and basically uses the perturbative + + + align:start position:0% +and basically uses the perturbative +information that you have available + + align:start position:0% +information that you have available + + + align:start position:0% +information that you have available +whether it's non ailan or + + align:start position:0% +whether it's non ailan or + + + align:start position:0% +whether it's non ailan or +ailon + + align:start position:0% +ailon + + + align:start position:0% +ailon +information + + align:start position:0% +information + + + align:start position:0% +information +yep so when you did the um well this + + align:start position:0% +yep so when you did the um well this + + + align:start position:0% +yep so when you did the um well this +calculation here that capital F is it + + align:start position:0% +calculation here that capital F is it + + + align:start position:0% +calculation here that capital F is it +the same result as we found like we or + + align:start position:0% +the same result as we found like we or + + + align:start position:0% +the same result as we found like we or +something that has like + + align:start position:0% +something that has like + + + align:start position:0% +something that has like +theal one and all that stuff as well um + + align:start position:0% +theal one and all that stuff as well um + + + align:start position:0% +theal one and all that stuff as well um +no it's just the U equals the half pole + + align:start position:0% +no it's just the U equals the half pole + + + align:start position:0% +no it's just the U equals the half pole +yeah so right so what we've done here + + align:start position:0% +yeah so right so what we've done here + + + align:start position:0% +yeah so right so what we've done here +and actually just going to come to this + + align:start position:0% +and actually just going to come to this + + + align:start position:0% +and actually just going to come to this +but I'll foreshadow so what we've done + + align:start position:0% +but I'll foreshadow so what we've done + + + align:start position:0% +but I'll foreshadow so what we've done +here is we set up a construction to + + align:start position:0% +here is we set up a construction to + + + align:start position:0% +here is we set up a construction to +remove the U equals a half pole and we + + align:start position:0% +remove the U equals a half pole and we + + + align:start position:0% +remove the U equals a half pole and we +did not remove any higher poles so you + + align:start position:0% +did not remove any higher poles so you + + + align:start position:0% +did not remove any higher poles so you +could we said the U equal a half is the + + align:start position:0% +could we said the U equal a half is the + + + align:start position:0% +could we said the U equal a half is the +most important let's get rid of that one + + align:start position:0% +most important let's get rid of that one + + + align:start position:0% +most important let's get rid of that one +from the msar mass there would be in + + align:start position:0% +from the msar mass there would be in + + + align:start position:0% +from the msar mass there would be in +principle higher ones and higher ones + + align:start position:0% +principle higher ones and higher ones + + + align:start position:0% +principle higher ones and higher ones +would basically we we had a some + + align:start position:0% +would basically we we had a some + + + align:start position:0% +would basically we we had a some +something that was proportional to R if + + align:start position:0% +something that was proportional to R if + + + align:start position:0% +something that was proportional to R if +you wanted to remove for that's for U + + align:start position:0% +you wanted to remove for that's for U + + + align:start position:0% +you wanted to remove for that's for U +equal a half if you wanted to remove + + align:start position:0% +equal a half if you wanted to remove + + + align:start position:0% +equal a half if you wanted to remove +higher ones you'd need terms + + align:start position:0% +higher ones you'd need terms + + + align:start position:0% +higher ones you'd need terms +proportional to R2 for example for = 1 + + align:start position:0% +proportional to R2 for example for = 1 + + + align:start position:0% +proportional to R2 for example for = 1 +Etc so we could have added more terms to + + align:start position:0% +Etc so we could have added more terms to + + + align:start position:0% +Etc so we could have added more terms to +do more but we didn't we just sort of + + align:start position:0% +do more but we didn't we just sort of + + + align:start position:0% +do more but we didn't we just sort of +removed the problem at U equals a half + + align:start position:0% +removed the problem at U equals a half + + + align:start position:0% +removed the problem at U equals a half +and that's why when we go through this + + align:start position:0% +and that's why when we go through this + + + align:start position:0% +and that's why when we go through this +you only see a u equals a half + + align:start position:0% + + + + align:start position:0% + +pole something you have to change the + + align:start position:0% +pole something you have to change the + + + align:start position:0% +pole something you have to change the +result of this yeah so the way you + + align:start position:0% +result of this yeah so the way you + + + align:start position:0% +result of this yeah so the way you +should think about it is that basically + + align:start position:0% +should think about it is that basically + + + align:start position:0% +should think about it is that basically +what you're doing is you're setting up a + + align:start position:0% +what you're doing is you're setting up a + + + align:start position:0% +what you're doing is you're setting up a +scheme change that perturbatively takes + + align:start position:0% +scheme change that perturbatively takes + + + align:start position:0% +scheme change that perturbatively takes +you out of msar towards something else + + align:start position:0% +you out of msar towards something else + + + align:start position:0% +you out of msar towards something else +you you remove the U equals a half and + + align:start position:0% +you you remove the U equals a half and + + + align:start position:0% +you you remove the U equals a half and +you get rid of that problem if you + + align:start position:0% +you get rid of that problem if you + + + align:start position:0% +you get rid of that problem if you +thought you had enough perturbative + + align:start position:0% +thought you had enough perturbative + + + align:start position:0% +thought you had enough perturbative +accuracy that you were seeing problems + + align:start position:0% +accuracy that you were seeing problems + + + align:start position:0% +accuracy that you were seeing problems +related to U equals 1 then you could + + align:start position:0% +related to U equals 1 then you could + + + align:start position:0% +related to U equals 1 then you could +make further scheme change with another + + align:start position:0% +make further scheme change with another + + + align:start position:0% +make further scheme change with another +series that's proportional to R 2 to get + + align:start position:0% +series that's proportional to R 2 to get + + + align:start position:0% +series that's proportional to R 2 to get +rid of that + + align:start position:0% +rid of that + + + align:start position:0% +rid of that +one so the would tell you about all the + + align:start position:0% +one so the would tell you about all the + + + align:start position:0% +one so the would tell you about all the +it would tell you about these ones too + + align:start position:0% +it would tell you about these ones too + + + align:start position:0% +it would tell you about these ones too +yeah absolutely + + align:start position:0% +yeah absolutely + + + align:start position:0% +yeah absolutely +so you can actually generalize this for + + align:start position:0% +so you can actually generalize this for + + + align:start position:0% +so you can actually generalize this for +arbit you know for R to the p and you + + align:start position:0% +arbit you know for R to the p and you + + + align:start position:0% +arbit you know for R to the p and you +can derive a sum rule for R to the p and + + align:start position:0% +can derive a sum rule for R to the p and + + + align:start position:0% +can derive a sum rule for R to the p and +it's a slightly more complicated formula + + align:start position:0% +it's a slightly more complicated formula + + + align:start position:0% +it's a slightly more complicated formula +here and then you'd have the P to P + + align:start position:0% +here and then you'd have the P to P + + + align:start position:0% +here and then you'd have the P to P +over2 + + align:start position:0% + + + + align:start position:0% + +pole all + + align:start position:0% +pole all + + + align:start position:0% +pole all +right okay so + + align:start position:0% +right okay so + + + align:start position:0% +right okay so +the sum + + align:start position:0% +the sum + + + align:start position:0% +the sum +rule is a + + align:start position:0% +rule is a + + + align:start position:0% +rule is a +probe alternate + + align:start position:0% +probe alternate + + + align:start position:0% +probe alternate +probe for the re normal + + align:start position:0% + + + + align:start position:0% + +on the NF bubbles are the classic one + + align:start position:0% +on the NF bubbles are the classic one + + + align:start position:0% +on the NF bubbles are the classic one +that people know + + align:start position:0% +that people know + + + align:start position:0% +that people know +about and this provides an + + align:start position:0% +about and this provides an + + + align:start position:0% +about and this provides an +alternate the nice thing about this is + + align:start position:0% +alternate the nice thing about this is + + + align:start position:0% +alternate the nice thing about this is +it also provides a series that con that + + align:start position:0% +it also provides a series that con that + + + align:start position:0% +it also provides a series that con that +you can look at the convergence where + + align:start position:0% +you can look at the convergence where + + + align:start position:0% +you can look at the convergence where +the NF bubbles just get a result see NF + + align:start position:0% +the NF bubbles just get a result see NF + + + align:start position:0% +the NF bubbles just get a result see NF +bubbles are good for finding out whether + + align:start position:0% +bubbles are good for finding out whether + + + align:start position:0% +bubbles are good for finding out whether +or not this thing has a r Alon if you + + align:start position:0% +or not this thing has a r Alon if you + + + align:start position:0% +or not this thing has a r Alon if you +get some non zero result then you expect + + align:start position:0% +get some non zero result then you expect + + + align:start position:0% +get some non zero result then you expect +that it does this way you could actually + + align:start position:0% +that it does this way you could actually + + + align:start position:0% +that it does this way you could actually +calculate the + + align:start position:0% +calculate the + + + align:start position:0% +calculate the +residue if you thought if you wanted to + + align:start position:0% +residue if you thought if you wanted to + + + align:start position:0% +residue if you thought if you wanted to +know that value for some + + align:start position:0% +know that value for some + + + align:start position:0% +know that value for some +reason + + align:start position:0% + + + + align:start position:0% + +okay and that actually might be useful + + align:start position:0% +okay and that actually might be useful + + + align:start position:0% +okay and that actually might be useful +for example if you wanted to think about + + align:start position:0% +for example if you wanted to think about + + + align:start position:0% +for example if you wanted to think about +higher normal on PS because you might + + align:start position:0% +higher normal on PS because you might + + + align:start position:0% +higher normal on PS because you might +want to say well let me get rid of the + + align:start position:0% +want to say well let me get rid of the + + + align:start position:0% +want to say well let me get rid of the +first one Whatever residue I can best + + align:start position:0% +first one Whatever residue I can best + + + align:start position:0% +first one Whatever residue I can best +approximate it for and see if there's + + align:start position:0% +approximate it for and see if there's + + + align:start position:0% +approximate it for and see if there's +another one + + align:start position:0% +another one + + + align:start position:0% +another one +underneath there's not really enough + + align:start position:0% +underneath there's not really enough + + + align:start position:0% +underneath there's not really enough +perturbative information that we have + + align:start position:0% +perturbative information that we have + + + align:start position:0% +perturbative information that we have +about qcd to be able to do that type of + + align:start position:0% +about qcd to be able to do that type of + + + align:start position:0% +about qcd to be able to do that type of +thing there's a few cases where U equals + + align:start position:0% +thing there's a few cases where U equals + + + align:start position:0% +thing there's a few cases where U equals +half is absent and then you can do that + + align:start position:0% +half is absent and then you can do that + + + align:start position:0% +half is absent and then you can do that +kind of thing I mean there's actually + + align:start position:0% +kind of thing I mean there's actually + + + align:start position:0% +kind of thing I mean there's actually +many cases where U equal a half is + + align:start position:0% +many cases where U equal a half is + + + align:start position:0% +many cases where U equal a half is +absent you can look for U equals 1 but + + align:start position:0% +absent you can look for U equals 1 but + + + align:start position:0% +absent you can look for U equals 1 but +looking for a subleading r normal one is + + align:start position:0% +looking for a subleading r normal one is + + + align:start position:0% +looking for a subleading r normal one is +something that nobody's found + + align:start position:0% +something that nobody's found + + + align:start position:0% +something that nobody's found +one people sometimes speculate about + + align:start position:0% +one people sometimes speculate about + + + align:start position:0% +one people sometimes speculate about +them because maybe the residue of the + + align:start position:0% +them because maybe the residue of the + + + align:start position:0% +them because maybe the residue of the +first one happens to be + + align:start position:0% +first one happens to be + + + align:start position:0% +first one happens to be +small this would allow you to test for + + align:start position:0% +small this would allow you to test for + + + align:start position:0% +small this would allow you to test for +that + + align:start position:0% + + + + align:start position:0% + +in to Decay people talk about + + align:start position:0% + + + + align:start position:0% + +that okay so let's come back and + + align:start position:0% +that okay so let's come back and + + + align:start position:0% +that okay so let's come back and +actually show you how you can use this + + align:start position:0% +actually show you how you can use this + + + align:start position:0% +actually show you how you can use this +technology for some phenomenological + + align:start position:0% +technology for some phenomenological + + + align:start position:0% +technology for some phenomenological +stuff and I want to do that by + + align:start position:0% +stuff and I want to do that by + + + align:start position:0% +stuff and I want to do that by +generalizing our discussion slightly + + align:start position:0% +generalizing our discussion slightly + + + align:start position:0% +generalizing our discussion slightly +away from masses towards just a general + + align:start position:0% +away from masses towards just a general + + + align:start position:0% +away from masses towards just a general +operator product + + align:start position:0% +operator product + + + align:start position:0% +operator product +expansion so everything that we've said + + align:start position:0% +expansion so everything that we've said + + + align:start position:0% +expansion so everything that we've said +here for masses can be applied more + + align:start position:0% +here for masses can be applied more + + + align:start position:0% +here for masses can be applied more +generally + + align:start position:0% +generally + + + align:start position:0% +generally +to an operator product + + align:start position:0% +to an operator product + + + align:start position:0% +to an operator product +expansion so let me show you why how + + align:start position:0% +expansion so let me show you why how + + + align:start position:0% +expansion so let me show you why how +what I + + align:start position:0% +what I + + + align:start position:0% +what I +mean so let's first consider what I mean + + align:start position:0% +mean so let's first consider what I mean + + + align:start position:0% +mean so let's first consider what I mean +by an operator product expansion in + + align:start position:0% +by an operator product expansion in + + + align:start position:0% +by an operator product expansion in +msar so you can think of this like maybe + + align:start position:0% +msar so you can think of this like maybe + + + align:start position:0% +msar so you can think of this like maybe +I'm integrating out a heavy + + align:start position:0% + + + + align:start position:0% + +particle and I'm writing a formula down + + align:start position:0% +particle and I'm writing a formula down + + + align:start position:0% +particle and I'm writing a formula down +and has some wison coefficients it has + + align:start position:0% +and has some wison coefficients it has + + + align:start position:0% +and has some wison coefficients it has +some + + align:start position:0% +some + + + align:start position:0% +some +operators and it's a TA it's a tailor + + align:start position:0% +operators and it's a TA it's a tailor + + + align:start position:0% +operators and it's a TA it's a tailor +Series in this parameter Q which is the + + align:start position:0% +Series in this parameter Q which is the + + + align:start position:0% +Series in this parameter Q which is the +hard scale high energy + + align:start position:0% +hard scale high energy + + + align:start position:0% +hard scale high energy +scale and I'm basically just expanding + + align:start position:0% +scale and I'm basically just expanding + + + align:start position:0% +scale and I'm basically just expanding +if you like in Lambda qcd over + + align:start position:0% +if you like in Lambda qcd over + + + align:start position:0% +if you like in Lambda qcd over +Q and The Operators are they're set by + + align:start position:0% +Q and The Operators are they're set by + + + align:start position:0% +Q and The Operators are they're set by +Lambda + + align:start position:0% +Lambda + + + align:start position:0% +Lambda +qcd so I'm going to take this guy to be + + align:start position:0% +qcd so I'm going to take this guy to be + + + align:start position:0% +qcd so I'm going to take this guy to be +dimensionless this is some dimensionless + + align:start position:0% +dimensionless this is some dimensionless + + + align:start position:0% +dimensionless this is some dimensionless +observable okay can always make it + + align:start position:0% +observable okay can always make it + + + align:start position:0% +observable okay can always make it +dimensionless by suitably + + align:start position:0% +dimensionless by suitably + + + align:start position:0% +dimensionless by suitably +choosing multiplying by appropriate Mass + + align:start position:0% +choosing multiplying by appropriate Mass + + + align:start position:0% +choosing multiplying by appropriate Mass +scales so then this is this here will be + + align:start position:0% +scales so then this is this here will be + + + align:start position:0% +scales so then this is this here will be +a dimensional Wilson + + align:start position:0% +a dimensional Wilson + + + align:start position:0% +a dimensional Wilson +coefficient and it's a Wilson + + align:start position:0% +coefficient and it's a Wilson + + + align:start position:0% +coefficient and it's a Wilson +coefficient in + + align:start position:0% +coefficient in + + + align:start position:0% +coefficient in +msar that's what the bar + + align:start position:0% +msar that's what the bar + + + align:start position:0% +msar that's what the bar +means and so this is an msar operator + + align:start position:0% +means and so this is an msar operator + + + align:start position:0% +means and so this is an msar operator +msar Matrix element of some + + align:start position:0% + + + + align:start position:0% + +operator and it's also + + align:start position:0% + + + + align:start position:0% + +dimensionless so this guy will be + + align:start position:0% +dimensionless so this guy will be + + + align:start position:0% +dimensionless so this guy will be +dimensionless + + align:start position:0% +dimensionless + + + align:start position:0% +dimensionless +too and finally this guy will have + + align:start position:0% +too and finally this guy will have + + + align:start position:0% +too and finally this guy will have +Dimension equals 1 + + align:start position:0% + + + + align:start position:0% + +now in msar what's beautiful about msar + + align:start position:0% +now in msar what's beautiful about msar + + + align:start position:0% +now in msar what's beautiful about msar +is that the series for these + + align:start position:0% +is that the series for these + + + align:start position:0% +is that the series for these +coefficients are very + + align:start position:0% +coefficients are very + + + align:start position:0% +coefficients are very +simple that's why people like + + align:start position:0% +simple that's why people like + + + align:start position:0% +simple that's why people like +to compute an MS + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +bar so if you look at what the series C + + align:start position:0% +bar so if you look at what the series C + + + align:start position:0% +bar so if you look at what the series C +bar looks + + align:start position:0% + + + + align:start position:0% + +like the form of it this as + + align:start position:0% + + + + align:start position:0% + +follows it's got dependence on mu over + + align:start position:0% +follows it's got dependence on mu over + + + align:start position:0% +follows it's got dependence on mu over +q and then alpha s of + + align:start position:0% + + + + align:start position:0% + +mu and these guys here are not an + + align:start position:0% +mu and these guys here are not an + + + align:start position:0% +mu and these guys here are not an +arbitrary function of mu over q but + + align:start position:0% +arbitrary function of mu over q but + + + align:start position:0% +arbitrary function of mu over q but +they're really just some + + align:start position:0% +they're really just some + + + align:start position:0% +they're really just some +logs so this looks like a series of + + align:start position:0% + + + + align:start position:0% + +logs so in mpar you're only seeing these + + align:start position:0% +logs so in mpar you're only seeing these + + + align:start position:0% +logs so in mpar you're only seeing these +log + + align:start position:0% +log + + + align:start position:0% +log +Ms so + + align:start position:0% + + + + align:start position:0% + +that's good from a computational point + + align:start position:0% +that's good from a computational point + + + align:start position:0% +that's good from a computational point +of + + align:start position:0% +of + + + align:start position:0% +of +view but we also know that in + + align:start position:0% +view but we also know that in + + + align:start position:0% +view but we also know that in +generically in this msar approach you + + align:start position:0% +generically in this msar approach you + + + align:start position:0% +generically in this msar approach you +may get sensitivity to re normal + + align:start position:0% + + + + align:start position:0% + +on it's also another thing we like about + + align:start position:0% +on it's also another thing we like about + + + align:start position:0% +on it's also another thing we like about +MSR is that it satisfies all the + + align:start position:0% +MSR is that it satisfies all the + + + align:start position:0% +MSR is that it satisfies all the +symmetries we want to keep doesn't mess + + align:start position:0% +symmetries we want to keep doesn't mess + + + align:start position:0% +symmetries we want to keep doesn't mess +them up so it's luren engaging + + align:start position:0% +them up so it's luren engaging + + + align:start position:0% +them up so it's luren engaging +arean which is always a good + + align:start position:0% + + + + align:start position:0% + +thing and not only is it simple for + + align:start position:0% +thing and not only is it simple for + + + align:start position:0% +thing and not only is it simple for +multi-loop computations but multi-loop + + align:start position:0% +multi-loop computations but multi-loop + + + align:start position:0% +multi-loop computations but multi-loop +computations are not even done in other + + align:start position:0% +computations are not even done in other + + + align:start position:0% +computations are not even done in other +schemes because they're just too + + align:start position:0% +schemes because they're just too + + + align:start position:0% +schemes because they're just too +difficult so it really makes multi-op + + align:start position:0% +difficult so it really makes multi-op + + + align:start position:0% +difficult so it really makes multi-op +computations possible + + align:start position:0% + + + + align:start position:0% + +and the bot there's only really this one + + align:start position:0% +and the bot there's only really this one + + + align:start position:0% +and the bot there's only really this one +bot that that has this R normal + + align:start position:0% +bot that that has this R normal + + + align:start position:0% +bot that that has this R normal +on + + align:start position:0% + + + + align:start position:0% + +issue so we talked about re normal on + + align:start position:0% +issue so we talked about re normal on + + + align:start position:0% +issue so we talked about re normal on +for a mass and I just showed you what it + + align:start position:0% +for a mass and I just showed you what it + + + align:start position:0% +for a mass and I just showed you what it +was and then we explored it here let me + + align:start position:0% +was and then we explored it here let me + + + align:start position:0% +was and then we explored it here let me +tell you what the renormalon would + + align:start position:0% +tell you what the renormalon would + + + align:start position:0% +tell you what the renormalon would +be so generically what the ralon would + + align:start position:0% +be so generically what the ralon would + + + align:start position:0% +be so generically what the ralon would +be is the following you would have an + + align:start position:0% +be is the following you would have an + + + align:start position:0% +be is the following you would have an +ambiguity in the coefficient see c0 + + align:start position:0% + + + + align:start position:0% + +bar it's of the size Lambda qcd over M + + align:start position:0% +bar it's of the size Lambda qcd over M + + + align:start position:0% +bar it's of the size Lambda qcd over M +over whatever the scale Q + + align:start position:0% + + + + align:start position:0% + +is and you would have a the same + + align:start position:0% +is and you would have a the same + + + align:start position:0% +is and you would have a the same +ambiguity in this Theta 1 + + align:start position:0% +ambiguity in this Theta 1 + + + align:start position:0% +ambiguity in this Theta 1 +bar so this Theta 1 bar which is an msar + + align:start position:0% +bar so this Theta 1 bar which is an msar + + + align:start position:0% +bar so this Theta 1 bar which is an msar +Matrix element has an + + align:start position:0% +Matrix element has an + + + align:start position:0% +Matrix element has an +ambiguity is a border Lambda + + align:start position:0% +ambiguity is a border Lambda + + + align:start position:0% +ambiguity is a border Lambda +qcd this guy has an ambiguity and those + + align:start position:0% +qcd this guy has an ambiguity and those + + + align:start position:0% +qcd this guy has an ambiguity and those +ambiguities cancel so you're dividing up + + align:start position:0% +ambiguities cancel so you're dividing up + + + align:start position:0% +ambiguities cancel so you're dividing up +the physics again in msar into short + + align:start position:0% +the physics again in msar into short + + + align:start position:0% +the physics again in msar into short +distance physics and longdistance + + align:start position:0% +distance physics and longdistance + + + align:start position:0% +distance physics and longdistance +physics and the interesting thing is + + align:start position:0% +physics and the interesting thing is + + + align:start position:0% +physics and the interesting thing is +that it's there's a piece of short + + align:start position:0% +that it's there's a piece of short + + + align:start position:0% +that it's there's a piece of short +there's a piece of longdistance physics + + align:start position:0% +there's a piece of longdistance physics + + + align:start position:0% +there's a piece of longdistance physics +trapped in the c0 that should be if you + + align:start position:0% +trapped in the c0 that should be if you + + + align:start position:0% +trapped in the c0 that should be if you +really wanted it should be physically in + + align:start position:0% +really wanted it should be physically in + + + align:start position:0% +really wanted it should be physically in +the Theta one bar and vice versa so um + + align:start position:0% +the Theta one bar and vice versa so um + + + align:start position:0% +the Theta one bar and vice versa so um +so really what's the problem with Ms bar + + align:start position:0% +so really what's the problem with Ms bar + + + align:start position:0% +so really what's the problem with Ms bar +is that there's a piece of something + + align:start position:0% +is that there's a piece of something + + + align:start position:0% +is that there's a piece of something +that you want in Theta 1 bar but ends up + + align:start position:0% +that you want in Theta 1 bar but ends up + + + align:start position:0% +that you want in Theta 1 bar but ends up +just being in the c0 bar and that's what + + align:start position:0% +just being in the c0 bar and that's what + + + align:start position:0% +just being in the c0 bar and that's what +I mean by this that there's something + + align:start position:0% +I mean by this that there's something + + + align:start position:0% +I mean by this that there's something +here which is infrared sensitive + + align:start position:0% +here which is infrared sensitive + + + align:start position:0% +here which is infrared sensitive +correspondingly there's kind of a + + align:start position:0% +correspondingly there's kind of a + + + align:start position:0% +correspondingly there's kind of a +ultraviolet sensitivity in this Theta 1 + + align:start position:0% +ultraviolet sensitivity in this Theta 1 + + + align:start position:0% +ultraviolet sensitivity in this Theta 1 +bar and you'd like to get that + + align:start position:0% +bar and you'd like to get that + + + align:start position:0% +bar and you'd like to get that +rearranged in an appropriate way and + + align:start position:0% +rearranged in an appropriate way and + + + align:start position:0% +rearranged in an appropriate way and +that's like this kind of rearrangement + + align:start position:0% +that's like this kind of rearrangement + + + align:start position:0% +that's like this kind of rearrangement +we were making by changing schemes for + + align:start position:0% +we were making by changing schemes for + + + align:start position:0% +we were making by changing schemes for +masses except here it's going to be + + align:start position:0% +masses except here it's going to be + + + align:start position:0% +masses except here it's going to be +changing schemes for Wilson + + align:start position:0% + + + + align:start position:0% + +coefficients so this thing + + align:start position:0% + + + + align:start position:0% + +here is it what we would call a u equal + + align:start position:0% +here is it what we would call a u equal + + + align:start position:0% +here is it what we would call a u equal +1un + + align:start position:0% + + + + align:start position:0% + +one so what happens with u equal 1 is + + align:start position:0% +one so what happens with u equal 1 is + + + align:start position:0% +one so what happens with u equal 1 is +that you make a connection between the + + align:start position:0% +that you make a connection between the + + + align:start position:0% +that you make a connection between the +leading order term and the power + + align:start position:0% +leading order term and the power + + + align:start position:0% +leading order term and the power +suppressed + + align:start position:0% +suppressed + + + align:start position:0% +suppressed +term that's what happens with the Delta + + align:start position:0% +term that's what happens with the Delta + + + align:start position:0% +term that's what happens with the Delta +c0 + + align:start position:0% + + + + align:start position:0% + +bar so in order to flesh out a little + + align:start position:0% +bar so in order to flesh out a little + + + align:start position:0% +bar so in order to flesh out a little +bit better what I just said in words + + align:start position:0% +bit better what I just said in words + + + align:start position:0% +bit better what I just said in words +let's pretend that we understand what + + align:start position:0% +let's pretend that we understand what + + + align:start position:0% +let's pretend that we understand what +the theory is and let's just pretend + + align:start position:0% +the theory is and let's just pretend + + + align:start position:0% +the theory is and let's just pretend +it's some integral + + align:start position:0% +it's some integral + + + align:start position:0% +it's some integral +and I'll just show you what is going on + + align:start position:0% + + + + align:start position:0% + +here so let's imagine that our + + align:start position:0% +here so let's imagine that our + + + align:start position:0% +here so let's imagine that our +theory is an integral instead of a + + align:start position:0% +theory is an integral instead of a + + + align:start position:0% +theory is an integral instead of a +Quantum the theory it's a one + + align:start position:0% +Quantum the theory it's a one + + + align:start position:0% +Quantum the theory it's a one +dimensional integral + + align:start position:0% + + + + align:start position:0% + +and it has two + + align:start position:0% +and it has two + + + align:start position:0% +and it has two +scales one which I'll call Lambda qcd + + align:start position:0% +scales one which I'll call Lambda qcd + + + align:start position:0% +scales one which I'll call Lambda qcd +which is some low scale and one which + + align:start position:0% +which is some low scale and one which + + + align:start position:0% +which is some low scale and one which +I'll call + + align:start position:0% +I'll call + + + align:start position:0% +I'll call +Q which is some high + + align:start position:0% +Q which is some high + + + align:start position:0% +Q which is some high +scale and I'm using a notation where the + + align:start position:0% +scale and I'm using a notation where the + + + align:start position:0% +scale and I'm using a notation where the +integral could diverge and i' regulate + + align:start position:0% +integral could diverge and i' regulate + + + align:start position:0% +integral could diverge and i' regulate +it with a dimensional regularization + + align:start position:0% +it with a dimensional regularization + + + align:start position:0% +it with a dimensional regularization +type uh parameter so I'm doing a + + align:start position:0% +type uh parameter so I'm doing a + + + align:start position:0% +type uh parameter so I'm doing a +one-dimensional integral but continua + + align:start position:0% +one-dimensional integral but continua + + + align:start position:0% +one-dimensional integral but continua +into Epsilon Dimensions to regulate any + + align:start position:0% + + + + align:start position:0% + +divergences so what msar does with this + + align:start position:0% +divergences so what msar does with this + + + align:start position:0% +divergences so what msar does with this +integral is it just says well I'm not + + align:start position:0% +integral is it just says well I'm not + + + align:start position:0% +integral is it just says well I'm not +going to change the limits of the + + align:start position:0% +going to change the limits of the + + + align:start position:0% +going to change the limits of the +integral I'm just going to either expand + + align:start position:0% +integral I'm just going to either expand + + + align:start position:0% +integral I'm just going to either expand +out this F or expand out this + + align:start position:0% +out this F or expand out this + + + align:start position:0% +out this F or expand out this +denominator I'll do two different tailor + + align:start position:0% +denominator I'll do two different tailor + + + align:start position:0% +denominator I'll do two different tailor +series and then I'll put them together + + align:start position:0% +series and then I'll put them together + + + align:start position:0% +series and then I'll put them together +and that's basically well how I'm + + align:start position:0% + + + + align:start position:0% + +identifying the terms in my + + align:start position:0% + + + + align:start position:0% + +op so msar + + align:start position:0% + + + + align:start position:0% + +so I sort of associate there being a + + align:start position:0% +so I sort of associate there being a + + + align:start position:0% +so I sort of associate there being a +high energy piece where K is of order + + align:start position:0% +high energy piece where K is of order + + + align:start position:0% +high energy piece where K is of order +q and then there's some low energy + + align:start position:0% +q and then there's some low energy + + + align:start position:0% +q and then there's some low energy +piece I don't change the limits + + align:start position:0% + + + + align:start position:0% + +so in the low energy piece I keep the + + align:start position:0% +so in the low energy piece I keep the + + + align:start position:0% +so in the low energy piece I keep the +full function + + align:start position:0% +full function + + + align:start position:0% +full function +f and then I expand + + align:start position:0% +f and then I expand + + + align:start position:0% +f and then I expand +out the other + + align:start position:0% + + + + align:start position:0% + +thing and if I drop the dots in this + + align:start position:0% +thing and if I drop the dots in this + + + align:start position:0% +thing and if I drop the dots in this +formula I can identify these integrals + + align:start position:0% +formula I can identify these integrals + + + align:start position:0% +formula I can identify these integrals +as toy models for the things that are + + align:start position:0% +as toy models for the things that are + + + align:start position:0% +as toy models for the things that are +appearing in my + + align:start position:0% +appearing in my + + + align:start position:0% +appearing in my +op let me write that op again + + align:start position:0% + + + + align:start position:0% + +so here these things are one this + + align:start position:0% +so here these things are one this + + + align:start position:0% +so here these things are one this +example this integral here which is over + + align:start position:0% +example this integral here which is over + + + align:start position:0% +example this integral here which is over +high energy scales K dominated by Q is + + align:start position:0% +high energy scales K dominated by Q is + + + align:start position:0% +high energy scales K dominated by Q is +this + + align:start position:0% + + + + align:start position:0% + +guy and this integral here where K is of + + align:start position:0% +guy and this integral here where K is of + + + align:start position:0% +guy and this integral here where K is of +order Lambda qcd effectively there's a + + align:start position:0% +order Lambda qcd effectively there's a + + + align:start position:0% +order Lambda qcd effectively there's a +one over Q which is this one over Q + + align:start position:0% +one over Q which is this one over Q + + + align:start position:0% +one over Q which is this one over Q +that's giving me the operator Theta 1 + + align:start position:0% +that's giving me the operator Theta 1 + + + align:start position:0% +that's giving me the operator Theta 1 +bar okay so Wilson coefficient is the + + align:start position:0% +bar okay so Wilson coefficient is the + + + align:start position:0% +bar okay so Wilson coefficient is the +high energy piece of the original thing + + align:start position:0% +high energy piece of the original thing + + + align:start position:0% +high energy piece of the original thing +Matrix element here is the low energy + + align:start position:0% +Matrix element here is the low energy + + + align:start position:0% +Matrix element here is the low energy +piece which is suppressed by one over + + align:start position:0% +piece which is suppressed by one over + + + align:start position:0% +piece which is suppressed by one over +Q + + align:start position:0% +Q + + + align:start position:0% +Q +okay but they both came from the same + + align:start position:0% +okay but they both came from the same + + + align:start position:0% +okay but they both came from the same +physics in the + + align:start position:0% +physics in the + + + align:start position:0% +physics in the +beginning and I just was expanding it + + align:start position:0% +beginning and I just was expanding it + + + align:start position:0% +beginning and I just was expanding it +because that's how I wanted to organize + + align:start position:0% +because that's how I wanted to organize + + + align:start position:0% +because that's how I wanted to organize +it now the thing about msar is that you + + align:start position:0% +it now the thing about msar is that you + + + align:start position:0% +it now the thing about msar is that you +integrate all the way down to zero there + + align:start position:0% +integrate all the way down to zero there + + + align:start position:0% +integrate all the way down to zero there +and you integrate all the way up to + + align:start position:0% +and you integrate all the way up to + + + align:start position:0% +and you integrate all the way up to +Infinity + + align:start position:0% +Infinity + + + align:start position:0% +Infinity +here okay and that's where the ralon + + align:start position:0% +here okay and that's where the ralon + + + align:start position:0% +here okay and that's where the ralon +problems come from + + align:start position:0% + + + + align:start position:0% + +so this little procedure here separates + + align:start position:0% +so this little procedure here separates + + + align:start position:0% +so this little procedure here separates +the long and short distance + + align:start position:0% +the long and short distance + + + align:start position:0% +the long and short distance +physics to the + + align:start position:0% + + + + align:start position:0% + +logs it does that + + align:start position:0% +logs it does that + + + align:start position:0% +logs it does that +correctly but for + + align:start position:0% +correctly but for + + + align:start position:0% +correctly but for +Powers we effectively rely on the fact + + align:start position:0% +Powers we effectively rely on the fact + + + align:start position:0% +Powers we effectively rely on the fact +that it set scal as integrals to zero + + align:start position:0% + + + + align:start position:0% + +that's what's forced Upon Us by the + + align:start position:0% +that's what's forced Upon Us by the + + + align:start position:0% +that's what's forced Upon Us by the +definition of msar and dimensional + + align:start position:0% + + + + align:start position:0% + +regularization and what goes wrong is + + align:start position:0% +regularization and what goes wrong is + + + align:start position:0% +regularization and what goes wrong is +basically that physically we're still + + align:start position:0% +basically that physically we're still + + + align:start position:0% +basically that physically we're still +integrating over regions of those + + align:start position:0% +integrating over regions of those + + + align:start position:0% +integrating over regions of those +integrals which are not associated to + + align:start position:0% +integrals which are not associated to + + + align:start position:0% +integrals which are not associated to +the to the physics that should be in + + align:start position:0% +the to the physics that should be in + + + align:start position:0% +the to the physics that should be in +those parameters + + align:start position:0% + + + + align:start position:0% + +okay so now this is a toy toy example + + align:start position:0% +okay so now this is a toy toy example + + + align:start position:0% +okay so now this is a toy toy example +but the same thing is happening in the + + align:start position:0% +but the same thing is happening in the + + + align:start position:0% +but the same thing is happening in the +quantum field Theory when you think + + align:start position:0% +quantum field Theory when you think + + + align:start position:0% +quantum field Theory when you think +about what you're doing when you write + + align:start position:0% +about what you're doing when you write + + + align:start position:0% +about what you're doing when you write +down fan diagrams and you construct a + + align:start position:0% +down fan diagrams and you construct a + + + align:start position:0% +down fan diagrams and you construct a +Wilson coefficient it's effectively the + + align:start position:0% +Wilson coefficient it's effectively the + + + align:start position:0% +Wilson coefficient it's effectively the +same thing in dimentional regularization + + align:start position:0% +same thing in dimentional regularization + + + align:start position:0% +same thing in dimentional regularization +you're integrating all our all values of + + align:start position:0% +you're integrating all our all values of + + + align:start position:0% +you're integrating all our all values of +the momentum and this little kind of toy + + align:start position:0% +the momentum and this little kind of toy + + + align:start position:0% +the momentum and this little kind of toy +analogy is actually apt for what's going + + align:start position:0% +analogy is actually apt for what's going + + + align:start position:0% +analogy is actually apt for what's going +on in a true operator product + + align:start position:0% +on in a true operator product + + + align:start position:0% +on in a true operator product +expansion what would happen if you did a + + align:start position:0% +expansion what would happen if you did a + + + align:start position:0% +expansion what would happen if you did a +wilsonian picture + + align:start position:0% + + + + align:start position:0% + +in our toy + + align:start position:0% +in our toy + + + align:start position:0% +in our toy +model well then you would cut off the + + align:start position:0% +model well then you would cut off the + + + align:start position:0% +model well then you would cut off the +integrals explicitly say let's introduce + + align:start position:0% +integrals explicitly say let's introduce + + + align:start position:0% +integrals explicitly say let's introduce +some + + align:start position:0% +some + + + align:start position:0% +some +scale Lambda + + align:start position:0% +scale Lambda + + + align:start position:0% +scale Lambda +F I could still think of expanding in + + align:start position:0% +F I could still think of expanding in + + + align:start position:0% +F I could still think of expanding in +the same + + align:start position:0% + + + + align:start position:0% + +way I don't need the dimensional + + align:start position:0% +way I don't need the dimensional + + + align:start position:0% +way I don't need the dimensional +regularization anymore so I'll set that + + align:start position:0% +regularization anymore so I'll set that + + + align:start position:0% +regularization anymore so I'll set that +get rid of + + align:start position:0% + + + + align:start position:0% + +that I think of breaking the integral + + align:start position:0% +that I think of breaking the integral + + + align:start position:0% +that I think of breaking the integral +into two pieces the low energy and high + + align:start position:0% +into two pieces the low energy and high + + + align:start position:0% +into two pieces the low energy and high +energy pieces and in each of those + + align:start position:0% +energy pieces and in each of those + + + align:start position:0% +energy pieces and in each of those +pieces I expand the integral in + + align:start position:0% +pieces I expand the integral in + + + align:start position:0% +pieces I expand the integral in +different + + align:start position:0% + + + + align:start position:0% + +ways so same type of expansion I'm just + + align:start position:0% +ways so same type of expansion I'm just + + + align:start position:0% +ways so same type of expansion I'm just +regulating it + + align:start position:0% +regulating it + + + align:start position:0% +regulating it +differently now I'm guaranteed that this + + align:start position:0% +differently now I'm guaranteed that this + + + align:start position:0% +differently now I'm guaranteed that this +is high energy and this is low + + align:start position:0% +is high energy and this is low + + + align:start position:0% +is high energy and this is low +energy and you could write down sort of + + align:start position:0% +energy and you could write down sort of + + + align:start position:0% +energy and you could write down sort of +what this is appr proxy for is a + + align:start position:0% +what this is appr proxy for is a + + + align:start position:0% +what this is appr proxy for is a +wilsonian op + + align:start position:0% + + + + align:start position:0% + +mu gets replaced by this scale LDA + + align:start position:0% +mu gets replaced by this scale LDA + + + align:start position:0% +mu gets replaced by this scale LDA +f everything gets a W for + + align:start position:0% + + + + align:start position:0% + +wilsonian so again this is one with our + + align:start position:0% +wilsonian so again this is one with our + + + align:start position:0% +wilsonian so again this is one with our +toy model this guy is this guy now this + + align:start position:0% +toy model this guy is this guy now this + + + align:start position:0% +toy model this guy is this guy now this +guy is this guy + + align:start position:0% +guy is this guy + + + align:start position:0% +guy is this guy +now so it's a very similar kind of + + align:start position:0% +now so it's a very similar kind of + + + align:start position:0% +now so it's a very similar kind of +Association but just the way that we're + + align:start position:0% +Association but just the way that we're + + + align:start position:0% +Association but just the way that we're +treating the integral is + + align:start position:0% +treating the integral is + + + align:start position:0% +treating the integral is +different and this way of doing things + + align:start position:0% +different and this way of doing things + + + align:start position:0% +different and this way of doing things +you don't have any problem with the + + align:start position:0% +you don't have any problem with the + + + align:start position:0% +you don't have any problem with the +normal one you just have an explicit cut + + align:start position:0% +normal one you just have an explicit cut + + + align:start position:0% +normal one you just have an explicit cut +off which says there's no low energy + + align:start position:0% +off which says there's no low energy + + + align:start position:0% +off which says there's no low energy +thing part of this and there's no high + + align:start position:0% +thing part of this and there's no high + + + align:start position:0% +thing part of this and there's no high +energy part of + + align:start position:0% +energy part of + + + align:start position:0% +energy part of +that I'm not + + align:start position:0% +that I'm not + + + align:start position:0% +that I'm not +integrating not integrating all the way + + align:start position:0% +integrating not integrating all the way + + + align:start position:0% +integrating not integrating all the way +down to zero in the first integral so I + + align:start position:0% +down to zero in the first integral so I + + + align:start position:0% +down to zero in the first integral so I +don't have any problems with the + + align:start position:0% +don't have any problems with the + + + align:start position:0% +don't have any problems with the +renormalon the renormalon came from + + align:start position:0% +renormalon the renormalon came from + + + align:start position:0% +renormalon the renormalon came from +infrared physics that was happening near + + align:start position:0% +infrared physics that was happening near + + + align:start position:0% +infrared physics that was happening near +k equal Z + + align:start position:0% +k equal Z + + + align:start position:0% +k equal Z +and in this one there's no sort of + + align:start position:0% +and in this one there's no sort of + + + align:start position:0% +and in this one there's no sort of +problem which would come from + + align:start position:0% + + + + align:start position:0% + +Infinity + + align:start position:0% +Infinity + + + align:start position:0% +Infinity +so in some sense this is what we'd like + + align:start position:0% +so in some sense this is what we'd like + + + align:start position:0% +so in some sense this is what we'd like +to + + align:start position:0% + + + + align:start position:0% + +do and the butt + + align:start position:0% +do and the butt + + + align:start position:0% +do and the butt +here is that it causes difficulties with + + align:start position:0% +here is that it causes difficulties with + + + align:start position:0% +here is that it causes difficulties with +symmetries + + align:start position:0% + + + + align:start position:0% + +in particular it generically breaks + + align:start position:0% +in particular it generically breaks + + + align:start position:0% +in particular it generically breaks +gauging + + align:start position:0% +gauging + + + align:start position:0% +gauging +variance and Loren and + + align:start position:0% + + + + align:start position:0% + +variance let's get + + align:start position:0% +variance let's get + + + align:start position:0% +variance let's get +broken and the calculations that you + + align:start position:0% +broken and the calculations that you + + + align:start position:0% +broken and the calculations that you +would like to do are just too + + align:start position:0% + + + + align:start position:0% + +difficult I don't know of anybody that's + + align:start position:0% +difficult I don't know of anybody that's + + + align:start position:0% +difficult I don't know of anybody that's +done + + align:start position:0% +done + + + align:start position:0% +done +maybe somebody's done two Loops in the + + align:start position:0% +maybe somebody's done two Loops in the + + + align:start position:0% +maybe somebody's done two Loops in the +wilsonian picture but nobody's ever done + + align:start position:0% +wilsonian picture but nobody's ever done + + + align:start position:0% +wilsonian picture but nobody's ever done +three okay so you have in some sense you + + align:start position:0% +three okay so you have in some sense you + + + align:start position:0% +three okay so you have in some sense you +have some nice things here you have some + + align:start position:0% +have some nice things here you have some + + + align:start position:0% +have some nice things here you have some +nice things here but they're not the + + align:start position:0% +nice things here but they're not the + + + align:start position:0% +nice things here but they're not the +same nice things and you'd like to have + + align:start position:0% +same nice things and you'd like to have + + + align:start position:0% +same nice things and you'd like to have +something that does the best of both and + + align:start position:0% +something that does the best of both and + + + align:start position:0% +something that does the best of both and +that's effectively what we're doing when + + align:start position:0% +that's effectively what we're doing when + + + align:start position:0% +that's effectively what we're doing when +we construct these R schemes what we're + + align:start position:0% +we construct these R schemes what we're + + + align:start position:0% +we construct these R schemes what we're +doing is we're saying well let's take + + align:start position:0% +doing is we're saying well let's take + + + align:start position:0% +doing is we're saying well let's take +msar as a starting point and try to get + + align:start position:0% +msar as a starting point and try to get + + + align:start position:0% +msar as a starting point and try to get +rid of the problem that it has by + + align:start position:0% +rid of the problem that it has by + + + align:start position:0% +rid of the problem that it has by +perturbing towards a wilsonian picture + + align:start position:0% + + + + align:start position:0% + +so what would an R scheme op look + + align:start position:0% + + + + align:start position:0% + +like start with + + align:start position:0% +like start with + + + align:start position:0% +like start with +msar and make a scheme + + align:start position:0% + + + + align:start position:0% + +change I make a scheme change here both + + align:start position:0% +change I make a scheme change here both + + + align:start position:0% +change I make a scheme change here both +to The Operators + + align:start position:0% + + + + align:start position:0% + +and the I make the same scheme change to + + align:start position:0% +and the I make the same scheme change to + + + align:start position:0% +and the I make the same scheme change to +the coefficient so I'm just really + + align:start position:0% +the coefficient so I'm just really + + + align:start position:0% +the coefficient so I'm just really +moving things + + align:start position:0% + + + + align:start position:0% + +around so let me just formally write + + align:start position:0% +around so let me just formally write + + + align:start position:0% +around so let me just formally write +down what such a scheme change would + + align:start position:0% +down what such a scheme change would + + + align:start position:0% +down what such a scheme change would +look like + + align:start position:0% + + + + align:start position:0% + +I set up some coefficients + + align:start position:0% + + + + align:start position:0% + +DN and I make the same I do a + + align:start position:0% +DN and I make the same I do a + + + align:start position:0% +DN and I make the same I do a +subtraction on The Operators and an + + align:start position:0% +subtraction on The Operators and an + + + align:start position:0% +subtraction on The Operators and an +addition on the coefficients in the way + + align:start position:0% +addition on the coefficients in the way + + + align:start position:0% +addition on the coefficients in the way +I've written + + align:start position:0% + + + + align:start position:0% + +it so that's just a rearrangement of the + + align:start position:0% +it so that's just a rearrangement of the + + + align:start position:0% +it so that's just a rearrangement of the +physics and we've set it up so so + + align:start position:0% + + + + align:start position:0% + +that the result of that looks like + + align:start position:0% + + + + align:start position:0% + +this I took in this + + align:start position:0% +this I took in this + + + align:start position:0% +this I took in this +example C1 equal to one for + + align:start position:0% +example C1 equal to one for + + + align:start position:0% +example C1 equal to one for +Simplicity a little more complicated if + + align:start position:0% +Simplicity a little more complicated if + + + align:start position:0% +Simplicity a little more complicated if +I want to keep it but we could keep it + + align:start position:0% +I want to keep it but we could keep it + + + align:start position:0% +I want to keep it but we could keep it +if we needed to so basically I've made a + + align:start position:0% +if we needed to so basically I've made a + + + align:start position:0% +if we needed to so basically I've made a +re a rearrangement to some equivalent op + + align:start position:0% +re a rearrangement to some equivalent op + + + align:start position:0% +re a rearrangement to some equivalent op +by just changing the thing the the + + align:start position:0% +by just changing the thing the the + + + align:start position:0% +by just changing the thing the the +definitions here but I have now the + + align:start position:0% +definitions here but I have now the + + + align:start position:0% +definitions here but I have now the +freedom to pick these D's and what I can + + align:start position:0% +freedom to pick these D's and what I can + + + align:start position:0% +freedom to pick these D's and what I can +do is I can pick the D's to have the + + align:start position:0% +do is I can pick the D's to have the + + + align:start position:0% +do is I can pick the D's to have the +same renormalon as the msar scheme and + + align:start position:0% +same renormalon as the msar scheme and + + + align:start position:0% +same renormalon as the msar scheme and +therefore I can iteratively again remove + + align:start position:0% +therefore I can iteratively again remove + + + align:start position:0% +therefore I can iteratively again remove +you know the first problematic term of + + align:start position:0% +you know the first problematic term of + + + align:start position:0% +you know the first problematic term of +this to get a better better defined + + align:start position:0% +this to get a better better defined + + + align:start position:0% +this to get a better better defined +Theta one and c0 just like we were doing + + align:start position:0% +Theta one and c0 just like we were doing + + + align:start position:0% +Theta one and c0 just like we were doing +for the + + align:start position:0% +for the + + + align:start position:0% +for the +masses so you can remove the U = 1 for + + align:start position:0% + + + + align:start position:0% + +example you can remove the U equal 1 + + align:start position:0% +example you can remove the U equal 1 + + + align:start position:0% +example you can remove the U equal 1 +Normal + + align:start position:0% + + + + align:start position:0% + +on by choose choosing the + + align:start position:0% +on by choose choosing the + + + align:start position:0% +on by choose choosing the +D and that's exactly what the wilsonian + + align:start position:0% +D and that's exactly what the wilsonian + + + align:start position:0% +D and that's exactly what the wilsonian +was trying to do for you and that's what + + align:start position:0% +was trying to do for you and that's what + + + align:start position:0% +was trying to do for you and that's what +it was doing for you with putting this + + align:start position:0% +it was doing for you with putting this + + + align:start position:0% +it was doing for you with putting this +cut off Ms bar was having problems at + + align:start position:0% +cut off Ms bar was having problems at + + + align:start position:0% +cut off Ms bar was having problems at +zero and we're sort of perturbatively + + align:start position:0% +zero and we're sort of perturbatively + + + align:start position:0% +zero and we're sort of perturbatively +removing those + + align:start position:0% +removing those + + + align:start position:0% +removing those +problems ctively going towards the + + align:start position:0% +problems ctively going towards the + + + align:start position:0% +problems ctively going towards the +wilsonian picture and the nice thing + + align:start position:0% +wilsonian picture and the nice thing + + + align:start position:0% +wilsonian picture and the nice thing +about this is that we can maintain the + + align:start position:0% +about this is that we can maintain the + + + align:start position:0% +about this is that we can maintain the +symmetries still Gage and variant still + + align:start position:0% +symmetries still Gage and variant still + + + align:start position:0% +symmetries still Gage and variant still +Loren and + + align:start position:0% + + + + align:start position:0% + +variant and we don't get the full sort + + align:start position:0% +variant and we don't get the full sort + + + align:start position:0% +variant and we don't get the full sort +of power of the wilsonian but we get + + align:start position:0% +of power of the wilsonian but we get + + + align:start position:0% +of power of the wilsonian but we get +closer to it and can in some sense get + + align:start position:0% +closer to it and can in some sense get + + + align:start position:0% +closer to it and can in some sense get +as close as we want Again by sort of + + align:start position:0% +as close as we want Again by sort of + + + align:start position:0% +as close as we want Again by sort of +perturbing us + + align:start position:0% +perturbing us + + + align:start position:0% +perturbing us +from order by + + align:start position:0% +from order by + + + align:start position:0% +from order by +order so what we introduce is power law + + align:start position:0% +order so what we introduce is power law + + + align:start position:0% +order so what we introduce is power law +dependence in + + align:start position:0% +dependence in + + + align:start position:0% +dependence in +R and that power law dependence is like + + align:start position:0% +R and that power law dependence is like + + + align:start position:0% +R and that power law dependence is like +the power law it's the analog of the + + align:start position:0% +the power law it's the analog of the + + + align:start position:0% +the power law it's the analog of the +power law dependence that would be in + + align:start position:0% +power law dependence that would be in + + + align:start position:0% +power law dependence that would be in +the Willian scheme so when you have + + align:start position:0% +the Willian scheme so when you have + + + align:start position:0% +the Willian scheme so when you have +integrals like this you would have + + align:start position:0% +integrals like this you would have + + + align:start position:0% +integrals like this you would have +powers there's nothing that stops you + + align:start position:0% +powers there's nothing that stops you + + + align:start position:0% +powers there's nothing that stops you +from having a complicated function of Q + + align:start position:0% +from having a complicated function of Q + + + align:start position:0% +from having a complicated function of Q +over Lambda and what we're saying is + + align:start position:0% +over Lambda and what we're saying is + + + align:start position:0% +over Lambda and what we're saying is +that the dominant kind of uh Power law + + align:start position:0% +that the dominant kind of uh Power law + + + align:start position:0% +that the dominant kind of uh Power law +sensitive terms here and here are + + align:start position:0% +sensitive terms here and here are + + + align:start position:0% +sensitive terms here and here are +captured by making this scheme + + align:start position:0% + + + + align:start position:0% + +change so we decide that we like msar + + align:start position:0% +change so we decide that we like msar + + + align:start position:0% +change so we decide that we like msar +because we have calculations that other + + align:start position:0% +because we have calculations that other + + + align:start position:0% +because we have calculations that other +people have done + + align:start position:0% + + + + align:start position:0% + +hopefully after three Loop order you + + align:start position:0% +hopefully after three Loop order you + + + align:start position:0% +hopefully after three Loop order you +certainly hope that someone else spent + + align:start position:0% +certainly hope that someone else spent + + + align:start position:0% +certainly hope that someone else spent +two years of their life on it rather + + align:start position:0% +two years of their life on it rather + + + align:start position:0% +two years of their life on it rather +than + + align:start position:0% + + + + align:start position:0% + +you and you can take and perturb your + + align:start position:0% +you and you can take and perturb your + + + align:start position:0% +you and you can take and perturb your +results from + + align:start position:0% +results from + + + align:start position:0% +results from +msbar towards a gage inv variant Loren + + align:start position:0% +msbar towards a gage inv variant Loren + + + align:start position:0% +msbar towards a gage inv variant Loren +inv variant version of wilsonian + + align:start position:0% + + + + align:start position:0% + +of the wilsonian + + align:start position:0% + + + + align:start position:0% + +picture so let me give you one example + + align:start position:0% +picture so let me give you one example + + + align:start position:0% +picture so let me give you one example +of that to show you in + + align:start position:0% +of that to show you in + + + align:start position:0% +of that to show you in +practice putting in some + + align:start position:0% +practice putting in some + + + align:start position:0% +practice putting in some +numbers oh I'm not quite there + + align:start position:0% + + + + align:start position:0% + +yet okay so let me give you a well- + + align:start position:0% +yet okay so let me give you a well- + + + align:start position:0% +yet okay so let me give you a well- +defined scheme which is analogous to the + + align:start position:0% +defined scheme which is analogous to the + + + align:start position:0% +defined scheme which is analogous to the +scheme that we just talked about with + + align:start position:0% +scheme that we just talked about with + + + align:start position:0% +scheme that we just talked about with +which was MSR scheme for the mass + + align:start position:0% +which was MSR scheme for the mass + + + align:start position:0% +which was MSR scheme for the mass +there's also an MSR scheme for the + + align:start position:0% +there's also an MSR scheme for the + + + align:start position:0% +there's also an MSR scheme for the +op and again the attitude is let's not + + align:start position:0% +op and again the attitude is let's not + + + align:start position:0% +op and again the attitude is let's not +calculate anything new that we don't + + align:start position:0% +calculate anything new that we don't + + + align:start position:0% +calculate anything new that we don't +have to so we'll reuse the coefficients + + align:start position:0% +have to so we'll reuse the coefficients + + + align:start position:0% +have to so we'll reuse the coefficients +of + + align:start position:0% +of + + + align:start position:0% +of +msar those coefficients had the + + align:start position:0% +msar those coefficients had the + + + align:start position:0% +msar those coefficients had the +renormalon so if those coefficients were + + align:start position:0% +renormalon so if those coefficients were + + + align:start position:0% +renormalon so if those coefficients were +we called them a few minutes ago BN mu + + align:start position:0% +we called them a few minutes ago BN mu + + + align:start position:0% +we called them a few minutes ago BN mu +over + + align:start position:0% +over + + + align:start position:0% +over +Q we just reuse these at a different + + align:start position:0% + + + + align:start position:0% + +scale so what we do is we say DN of mu / + + align:start position:0% +scale so what we do is we say DN of mu / + + + align:start position:0% +scale so what we do is we say DN of mu / +R is defined to be the BN of mu + + align:start position:0% +R is defined to be the BN of mu + + + align:start position:0% +R is defined to be the BN of mu +R so these guys were the MSR + + align:start position:0% +R so these guys were the MSR + + + align:start position:0% +R so these guys were the MSR +coefficients these guys are whatever we + + align:start position:0% +coefficients these guys are whatever we + + + align:start position:0% +coefficients these guys are whatever we +decide to put into the series over there + + align:start position:0% +decide to put into the series over there + + + align:start position:0% +decide to put into the series over there +just take them to be equal that's the + + align:start position:0% +just take them to be equal that's the + + + align:start position:0% +just take them to be equal that's the +MSR + + align:start position:0% +MSR + + + align:start position:0% +MSR +scheme and then if you look at what the + + align:start position:0% +scheme and then if you look at what the + + + align:start position:0% +scheme and then if you look at what the +coefficient + + align:start position:0% +coefficient + + + align:start position:0% +coefficient +is if we just write out explicitly what + + align:start position:0% +is if we just write out explicitly what + + + align:start position:0% +is if we just write out explicitly what +the coefficient is by plugging in the + + align:start position:0% +the coefficient is by plugging in the + + + align:start position:0% +the coefficient is by plugging in the +series you can again see the kind + + align:start position:0% +series you can again see the kind + + + align:start position:0% +series you can again see the kind +of how it's provided a cut + + align:start position:0% + + + + align:start position:0% + +off so this was our original msar series + + align:start position:0% +off so this was our original msar series + + + align:start position:0% +off so this was our original msar series +BN of mu over Q we introduce a + + align:start position:0% +BN of mu over Q we introduce a + + + align:start position:0% +BN of mu over Q we introduce a +subtraction which is suppressed by R + + align:start position:0% +subtraction which is suppressed by R + + + align:start position:0% +subtraction which is suppressed by R +over Q times the same series + + align:start position:0% +over Q times the same series + + + align:start position:0% +over Q times the same series +BN and this R is providing kind of like + + align:start position:0% +BN and this R is providing kind of like + + + align:start position:0% +BN and this R is providing kind of like +a power law cut off on a problem that + + align:start position:0% +a power law cut off on a problem that + + + align:start position:0% +a power law cut off on a problem that +this guy + + align:start position:0% +this guy + + + align:start position:0% +this guy +had exactly a power LW cut off so again + + align:start position:0% +had exactly a power LW cut off so again + + + align:start position:0% +had exactly a power LW cut off so again +if you look at the renormalon in this + + align:start position:0% +if you look at the renormalon in this + + + align:start position:0% +if you look at the renormalon in this +thing this combined thing the re normal + + align:start position:0% +thing this combined thing the re normal + + + align:start position:0% +thing this combined thing the re normal +L is independent of R and + + align:start position:0% + + + + align:start position:0% + +Q when + + align:start position:0% + + + + align:start position:0% + +you so to look say you would just plug + + align:start position:0% +you so to look say you would just plug + + + align:start position:0% +you so to look say you would just plug +in the Bubble Series result you'd find + + align:start position:0% +in the Bubble Series result you'd find + + + align:start position:0% +in the Bubble Series result you'd find +actually that the r over Q here would + + align:start position:0% +actually that the r over Q here would + + + align:start position:0% +actually that the r over Q here would +cancel out and so that these would just + + align:start position:0% +cancel out and so that these would just + + + align:start position:0% +cancel out and so that these would just +exactly cancel each other + + align:start position:0% + + + + align:start position:0% + += 1 re normal + + align:start position:0% += 1 re normal + + + align:start position:0% += 1 re normal +one and again if I wanted to probe other + + align:start position:0% +one and again if I wanted to probe other + + + align:start position:0% +one and again if I wanted to probe other +re normal lines I'd have to consider + + align:start position:0% +re normal lines I'd have to consider + + + align:start position:0% +re normal lines I'd have to consider +other powers besides R over q but those + + align:start position:0% +other powers besides R over q but those + + + align:start position:0% +other powers besides R over q but those +actually in this op would be connected + + align:start position:0% +actually in this op would be connected + + + align:start position:0% +actually in this op would be connected +to other operators so there was there's + + align:start position:0% +to other operators so there was there's + + + align:start position:0% +to other operators so there was there's +other subleading normal lines here which + + align:start position:0% +other subleading normal lines here which + + + align:start position:0% +other subleading normal lines here which +could be connected to 1 over q^2 etc + + align:start position:0% +could be connected to 1 over q^2 etc + + + align:start position:0% +could be connected to 1 over q^2 etc +etc and an MS bar that generically will + + align:start position:0% +etc and an MS bar that generically will + + + align:start position:0% +etc and an MS bar that generically will +happen but usually it suffices just to + + align:start position:0% +happen but usually it suffices just to + + + align:start position:0% +happen but usually it suffices just to +worry about the first one since many + + align:start position:0% +worry about the first one since many + + + align:start position:0% +worry about the first one since many +people in the community that do these + + align:start position:0% +people in the community that do these + + + align:start position:0% +people in the community that do these +multi-loop calculations don't even worry + + align:start position:0% +multi-loop calculations don't even worry + + + align:start position:0% +multi-loop calculations don't even worry +about the first + + align:start position:0% +about the first + + + align:start position:0% +about the first +one + + align:start position:0% +one + + + align:start position:0% +one +um + + align:start position:0% + + + + align:start position:0% + +anyway okay so you can again after youve + + align:start position:0% +anyway okay so you can again after youve + + + align:start position:0% +anyway okay so you can again after youve +got this + + align:start position:0% +got this + + + align:start position:0% +got this +definition uh you could actually + + align:start position:0% +definition uh you could actually + + + align:start position:0% +definition uh you could actually +formally write this as c0 + + align:start position:0% +formally write this as c0 + + + align:start position:0% +formally write this as c0 +bar of Q comma mu if you want to think + + align:start position:0% +bar of Q comma mu if you want to think + + + align:start position:0% +bar of Q comma mu if you want to think +about what it + + align:start position:0% +about what it + + + align:start position:0% +about what it +is minus r over Q same Wilson + + align:start position:0% +is minus r over Q same Wilson + + + align:start position:0% +is minus r over Q same Wilson +coefficient + + align:start position:0% +coefficient + + + align:start position:0% +coefficient +replacing all the RS by all the q's by R + + align:start position:0% +replacing all the RS by all the q's by R + + + align:start position:0% +replacing all the RS by all the q's by R +okay so that's another way of saying + + align:start position:0% +okay so that's another way of saying + + + align:start position:0% +okay so that's another way of saying +what the scheme change is from msar + + align:start position:0% +what the scheme change is from msar + + + align:start position:0% +what the scheme change is from msar +results to to this + + align:start position:0% +results to to this + + + align:start position:0% +results to to this +result and this R is acting like an IR + + align:start position:0% +result and this R is acting like an IR + + + align:start position:0% +result and this R is acting like an IR +cut + + align:start position:0% + + + + align:start position:0% + +off to get rid of the bad + + align:start position:0% + + + + align:start position:0% + +problem and again we have a a + + align:start position:0% +problem and again we have a a + + + align:start position:0% +problem and again we have a a +normalization group so r d byd + + align:start position:0% +normalization group so r d byd + + + align:start position:0% +normalization group so r d byd +r of this this Wilson + + align:start position:0% + + + + align:start position:0% + +coefficient it's convenient to think + + align:start position:0% +coefficient it's convenient to think + + + align:start position:0% +coefficient it's convenient to think +about that renormalization group with + + align:start position:0% +about that renormalization group with + + + align:start position:0% +about that renormalization group with +the log cut off mu set equal to the + + align:start position:0% +the log cut off mu set equal to the + + + align:start position:0% +the log cut off mu set equal to the +Power log cut off + + align:start position:0% +Power log cut off + + + align:start position:0% +Power log cut off +R and it's very much like our masses + + align:start position:0% +R and it's very much like our masses + + + align:start position:0% +R and it's very much like our masses +there's some + + align:start position:0% +there's some + + + align:start position:0% +there's some +function with an r in front and we could + + align:start position:0% +function with an r in front and we could + + + align:start position:0% +function with an r in front and we could +formally write down solutions to + + align:start position:0% +formally write down solutions to + + + align:start position:0% +formally write down solutions to +it and we can explicitly plug in results + + align:start position:0% +it and we can explicitly plug in results + + + align:start position:0% +it and we can explicitly plug in results +given how many terms in the series we + + align:start position:0% +given how many terms in the series we + + + align:start position:0% +given how many terms in the series we +know in the MS barar series + + align:start position:0% +know in the MS barar series + + + align:start position:0% +know in the MS barar series +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +so all the anomalous dimensions of this + + align:start position:0% +so all the anomalous dimensions of this + + + align:start position:0% +so all the anomalous dimensions of this +Wilson coefficient would be determined + + align:start position:0% +Wilson coefficient would be determined + + + align:start position:0% +Wilson coefficient would be determined +by the msar series the original one + + align:start position:0% +by the msar series the original one + + + align:start position:0% +by the msar series the original one +because the scheme that we're defining + + align:start position:0% +because the scheme that we're defining + + + align:start position:0% +because the scheme that we're defining +is set up so that it uses those msar + + align:start position:0% + + + + align:start position:0% + +coefficients so what would the RG look + + align:start position:0% +coefficients so what would the RG look + + + align:start position:0% +coefficients so what would the RG look +like + + align:start position:0% + + + + align:start position:0% + +that's the same kind of structure as + + align:start position:0% +that's the same kind of structure as + + + align:start position:0% +that's the same kind of structure as +what we had for + + align:start position:0% + + + + align:start position:0% + +masses some gamma functions + + align:start position:0% + + + + align:start position:0% + +and you can think of this as some + + align:start position:0% +and you can think of this as some + + + align:start position:0% +and you can think of this as some +c0 if you want kind of to have a more + + align:start position:0% +c0 if you want kind of to have a more + + + align:start position:0% +c0 if you want kind of to have a more +standard notation you would say that + + align:start position:0% +standard notation you would say that + + + align:start position:0% +standard notation you would say that +this is some U + + align:start position:0% +this is some U + + + align:start position:0% +this is some U +function and this is a bit of abusive + + align:start position:0% +function and this is a bit of abusive + + + align:start position:0% +function and this is a bit of abusive +notation actually here + + align:start position:0% +notation actually here + + + align:start position:0% +notation actually here +because it's additive not + + align:start position:0% +because it's additive not + + + align:start position:0% +because it's additive not +multiplicative but if you allow me to + + align:start position:0% +multiplicative but if you allow me to + + + align:start position:0% +multiplicative but if you allow me to +put this guy into here then I can always + + align:start position:0% +put this guy into here then I can always + + + align:start position:0% +put this guy into here then I can always +write it this way and I'll just do that + + align:start position:0% +write it this way and I'll just do that + + + align:start position:0% +write it this way and I'll just do that +for convenience so I want to show you + + align:start position:0% +for convenience so I want to show you + + + align:start position:0% +for convenience so I want to show you +one example of how this plays out in + + align:start position:0% +one example of how this plays out in + + + align:start position:0% +one example of how this plays out in +practice this so and it's related to our + + align:start position:0% +practice this so and it's related to our + + + align:start position:0% +practice this so and it's related to our +discussion of + + align:start position:0% +discussion of + + + align:start position:0% +discussion of +HQ so one thing that we said about hqet + + align:start position:0% +HQ so one thing that we said about hqet + + + align:start position:0% +HQ so one thing that we said about hqet +is that you could calculate the + + align:start position:0% +is that you could calculate the + + + align:start position:0% +is that you could calculate the +following + + align:start position:0% + + + + align:start position:0% + +quantity so hqt makes some predictions + + align:start position:0% +quantity so hqt makes some predictions + + + align:start position:0% +quantity so hqt makes some predictions +about the B star and the B they were + + align:start position:0% +about the B star and the B they were + + + align:start position:0% +about the B star and the B they were +connected they were in a symmetry + + align:start position:0% +connected they were in a symmetry + + + align:start position:0% +connected they were in a symmetry +multiplet and when you took the + + align:start position:0% +multiplet and when you took the + + + align:start position:0% +multiplet and when you took the +difference of B Star and B and you took + + align:start position:0% +difference of B Star and B and you took + + + align:start position:0% +difference of B Star and B and you took +this combination it actually is purely + + align:start position:0% +this combination it actually is purely + + + align:start position:0% +this combination it actually is purely +perturbative because there's a + + align:start position:0% +perturbative because there's a + + + align:start position:0% +perturbative because there's a +non-perturbative parameter but it's + + align:start position:0% +non-perturbative parameter but it's + + + align:start position:0% +non-perturbative parameter but it's +actually if you treat the charm cork as + + align:start position:0% +actually if you treat the charm cork as + + + align:start position:0% +actually if you treat the charm cork as +heavy it's the same for charm and bottom + + align:start position:0% +heavy it's the same for charm and bottom + + + align:start position:0% +heavy it's the same for charm and bottom +and it cancels + + align:start position:0% +and it cancels + + + align:start position:0% +and it cancels +out so you can actually write down an MS + + align:start position:0% +out so you can actually write down an MS + + + align:start position:0% +out so you can actually write down an MS +bar operator product + + align:start position:0% +bar operator product + + + align:start position:0% +bar operator product +expansion which is technically defined + + align:start position:0% +expansion which is technically defined + + + align:start position:0% +expansion which is technically defined +in + + align:start position:0% +in + + + align:start position:0% +in +HQ and what it looks like is the first + + align:start position:0% +HQ and what it looks like is the first + + + align:start position:0% +HQ and what it looks like is the first +thing is just a ratio of Wilson + + align:start position:0% +thing is just a ratio of Wilson + + + align:start position:0% +thing is just a ratio of Wilson +coefficients so we talked about this and + + align:start position:0% +coefficients so we talked about this and + + + align:start position:0% +coefficients so we talked about this and +we plugged in the sort of leading log + + align:start position:0% +we plugged in the sort of leading log + + + align:start position:0% +we plugged in the sort of leading log +result and we saw that it was working + + align:start position:0% +result and we saw that it was working + + + align:start position:0% +result and we saw that it was working +actually pretty + + align:start position:0% + + + + align:start position:0% + +well and if you were to kind of look at + + align:start position:0% +well and if you were to kind of look at + + + align:start position:0% +well and if you were to kind of look at +higher order terms in that op there + + align:start position:0% +higher order terms in that op there + + + align:start position:0% +higher order terms in that op there +would be some power corrections to + + align:start position:0% +would be some power corrections to + + + align:start position:0% +would be some power corrections to +that they've got some traditional names + + align:start position:0% +that they've got some traditional names + + + align:start position:0% +that they've got some traditional names +the names are not too + + align:start position:0% +the names are not too + + + align:start position:0% +the names are not too +important but this is like the one the + + align:start position:0% +important but this is like the one the + + + align:start position:0% +important but this is like the one the +analog of the one over Q term okay this + + align:start position:0% +analog of the one over Q term okay this + + + align:start position:0% +analog of the one over Q term okay this +is the one/ Q term this is the leading + + align:start position:0% +is the one/ Q term this is the leading + + + align:start position:0% +is the one/ Q term this is the leading +order term which is purely perturbative + + align:start position:0% +order term which is purely perturbative + + + align:start position:0% +order term which is purely perturbative +there's no Matrix element here it's just + + align:start position:0% +there's no Matrix element here it's just + + + align:start position:0% +there's no Matrix element here it's just +y + + align:start position:0% +y + + + align:start position:0% +y +this is a higher Dimension operator this + + align:start position:0% +this is a higher Dimension operator this + + + align:start position:0% +this is a higher Dimension operator this +guy scales like Lambda qcd cubed over + + align:start position:0% +guy scales like Lambda qcd cubed over + + + align:start position:0% +guy scales like Lambda qcd cubed over +Lambda qcd + + align:start position:0% +Lambda qcd + + + align:start position:0% +Lambda qcd +s which is just Lambda + + align:start position:0% +s which is just Lambda + + + align:start position:0% +s which is just Lambda +qcd so that's like the Lambda qcd or Q + + align:start position:0% +qcd so that's like the Lambda qcd or Q + + + align:start position:0% +qcd so that's like the Lambda qcd or Q +term and this is the formula you would + + align:start position:0% +term and this is the formula you would + + + align:start position:0% +term and this is the formula you would +write down if you wanted to make a + + align:start position:0% +write down if you wanted to make a + + + align:start position:0% +write down if you wanted to make a +prediction for this thing at higher + + align:start position:0% +prediction for this thing at higher + + + align:start position:0% +prediction for this thing at higher +Precision in + + align:start position:0% +Precision in + + + align:start position:0% +Precision in +msar so what happens if I think about + + align:start position:0% +msar so what happens if I think about + + + align:start position:0% +msar so what happens if I think about +this perturbative result at higher + + align:start position:0% +this perturbative result at higher + + + align:start position:0% +this perturbative result at higher +orders so people have actually + + align:start position:0% +orders so people have actually + + + align:start position:0% +orders so people have actually +calculated that coefficient into three + + align:start position:0% +calculated that coefficient into three + + + align:start position:0% +calculated that coefficient into three +Loop order and here's what it looks + + align:start position:0% + + + + align:start position:0% + +like so at order Alpha you get + + align:start position:0% + + + + align:start position:0% + +-113 at order Alpha + + align:start position:0% +-113 at order Alpha + + + align:start position:0% +-113 at order Alpha +squar getus + + align:start position:0% +squar getus + + + align:start position:0% +squar getus +078 and then you get + + align:start position:0% +078 and then you get + + + align:start position:0% +078 and then you get +anotherus + + align:start position:0% +anotherus + + + align:start position:0% +anotherus +0755 at Alpha + + align:start position:0% +0755 at Alpha + + + align:start position:0% +0755 at Alpha +cubed doesn't look so + + align:start position:0% +cubed doesn't look so + + + align:start position:0% +cubed doesn't look so +pretty all right so each order that you + + align:start position:0% +pretty all right so each order that you + + + align:start position:0% +pretty all right so each order that you +calculate is giving you a Corrections is + + align:start position:0% +calculate is giving you a Corrections is + + + align:start position:0% +calculate is giving you a Corrections is +about the same size as the previous + + align:start position:0% +about the same size as the previous + + + align:start position:0% +about the same size as the previous +order well you might say of course + + align:start position:0% +order well you might say of course + + + align:start position:0% +order well you might say of course +there's logs so I should resum the logs + + align:start position:0% +there's logs so I should resum the logs + + + align:start position:0% +there's logs so I should resum the logs +so let's resum the + + align:start position:0% + + + + align:start position:0% + +logs so leading + + align:start position:0% + + + + align:start position:0% + +log and then I get since I have higher + + align:start position:0% +log and then I get since I have higher + + + align:start position:0% +log and then I get since I have higher +order in almost Dimensions let me put in + + align:start position:0% +order in almost Dimensions let me put in + + + align:start position:0% +order in almost Dimensions let me put in +next deleting + + align:start position:0% +next deleting + + + align:start position:0% +next deleting +log and actually I have one more order + + align:start position:0% +log and actually I have one more order + + + align:start position:0% +log and actually I have one more order +so let me put that in + + align:start position:0% +so let me put that in + + + align:start position:0% +so let me put that in +too 908 + + align:start position:0% +too 908 + + + align:start position:0% +too 908 +next for next leading + + align:start position:0% +next for next leading + + + align:start position:0% +next for next leading +log uh + + align:start position:0% +log uh + + + align:start position:0% +log uh +oh all right so this is the one that we + + align:start position:0% +oh all right so this is the one that we + + + align:start position:0% +oh all right so this is the one that we +actually talked about earlier and that + + align:start position:0% +actually talked about earlier and that + + + align:start position:0% +actually talked about earlier and that +one is actually close to the + + align:start position:0% +one is actually close to the + + + align:start position:0% +one is actually close to the +data the leading log result was sort of + + align:start position:0% +data the leading log result was sort of + + + align:start position:0% +data the leading log result was sort of +close to what the data + + align:start position:0% +close to what the data + + + align:start position:0% +close to what the data +was but when you think about whether + + align:start position:0% +was but when you think about whether + + + align:start position:0% +was but when you think about whether +that's actually right and you calculate + + align:start position:0% +that's actually right and you calculate + + + align:start position:0% +that's actually right and you calculate +the higher order Corrections you find + + align:start position:0% +the higher order Corrections you find + + + align:start position:0% +the higher order Corrections you find +that you're moving away from the data + + align:start position:0% +that you're moving away from the data + + + align:start position:0% +that you're moving away from the data +right and again it's not convergent + + align:start position:0% +right and again it's not convergent + + + align:start position:0% +right and again it's not convergent +soing the logs has not helped you and + + align:start position:0% +soing the logs has not helped you and + + + align:start position:0% +soing the logs has not helped you and +that's because what we're talking about + + align:start position:0% +that's because what we're talking about + + + align:start position:0% +that's because what we're talking about +here has nothing to do with logs has to + + align:start position:0% +here has nothing to do with logs has to + + + align:start position:0% +here has nothing to do with logs has to +do with powers it's the normal on that's + + align:start position:0% +do with powers it's the normal on that's + + + align:start position:0% +do with powers it's the normal on that's +causing this + + align:start position:0% +causing this + + + align:start position:0% +causing this +problem okay so we could throw up our + + align:start position:0% +problem okay so we could throw up our + + + align:start position:0% +problem okay so we could throw up our +hands and say oh doesn't work or we + + align:start position:0% +hands and say oh doesn't work or we + + + align:start position:0% +hands and say oh doesn't work or we +could try to do something + + align:start position:0% +could try to do something + + + align:start position:0% +could try to do something +better so let me show you what happens + + align:start position:0% +better so let me show you what happens + + + align:start position:0% +better so let me show you what happens +if we do some of this stuff that I've + + align:start position:0% +if we do some of this stuff that I've + + + align:start position:0% +if we do some of this stuff that I've +been telling you + + align:start position:0% +been telling you + + + align:start position:0% +been telling you +about so this guy + + align:start position:0% +about so this guy + + + align:start position:0% +about so this guy +has a = one or normal on you can check + + align:start position:0% +has a = one or normal on you can check + + + align:start position:0% +has a = one or normal on you can check +that very easily by doing a bubble sum + + align:start position:0% + + + + align:start position:0% + +switch to the MSR + + align:start position:0% + + + + align:start position:0% + +scheme so we reuse our perturbative + + align:start position:0% +scheme so we reuse our perturbative + + + align:start position:0% +scheme so we reuse our perturbative +information in msar but just organizing + + align:start position:0% +information in msar but just organizing + + + align:start position:0% +information in msar but just organizing +a more intelligent + + align:start position:0% + + + + align:start position:0% + +fashion we Define a coefficient + + align:start position:0% + + + + align:start position:0% + +as + + align:start position:0% + + + + align:start position:0% + +above saying that this problem must have + + align:start position:0% +above saying that this problem must have + + + align:start position:0% +above saying that this problem must have +to do with that normal on and then if we + + align:start position:0% +to do with that normal on and then if we + + + align:start position:0% +to do with that normal on and then if we +write + + align:start position:0% + + + + align:start position:0% + +down what the op looks + + align:start position:0% + + + + align:start position:0% + +like we have again an + + align:start position:0% +like we have again an + + + align:start position:0% +like we have again an +op and we've changed Matrix element + + align:start position:0% +op and we've changed Matrix element + + + align:start position:0% +op and we've changed Matrix element +definitions as well as Wilson + + align:start position:0% +definitions as well as Wilson + + + align:start position:0% +definitions as well as Wilson +coefficients def definitions so I'm + + align:start position:0% +coefficients def definitions so I'm + + + align:start position:0% +coefficients def definitions so I'm +putting everything this scale + + align:start position:0% + + + + align:start position:0% + +r0o so that's just the rewriting the op + + align:start position:0% +r0o so that's just the rewriting the op + + + align:start position:0% +r0o so that's just the rewriting the op +in this new + + align:start position:0% + + + + align:start position:0% + +scheme when we look at this scheme and + + align:start position:0% +scheme when we look at this scheme and + + + align:start position:0% +scheme when we look at this scheme and +we think about what's going on we want + + align:start position:0% +we think about what's going on we want + + + align:start position:0% +we think about what's going on we want +to choose the r0o to be a void Lambda + + align:start position:0% +to choose the r0o to be a void Lambda + + + align:start position:0% +to choose the r0o to be a void Lambda +qcd or a bit bigger and the reason we + + align:start position:0% +qcd or a bit bigger and the reason we + + + align:start position:0% +qcd or a bit bigger and the reason we +want to do that is to preserve power + + align:start position:0% +want to do that is to preserve power + + + align:start position:0% +want to do that is to preserve power +power + + align:start position:0% + + + + align:start position:0% + +counting so power counting is + + align:start position:0% +counting so power counting is + + + align:start position:0% +counting so power counting is +important when we're making expansions + + align:start position:0% +important when we're making expansions + + + align:start position:0% +important when we're making expansions +in some sense it's + + align:start position:0% +in some sense it's + + + align:start position:0% +in some sense it's +key and if we + + align:start position:0% +key and if we + + + align:start position:0% +key and if we +thought that the original msar Matrix + + align:start position:0% +thought that the original msar Matrix + + + align:start position:0% +thought that the original msar Matrix +element was dominated by the scale + + align:start position:0% +element was dominated by the scale + + + align:start position:0% +element was dominated by the scale +Lambda qcd we better not screw that + + align:start position:0% +Lambda qcd we better not screw that + + + align:start position:0% +Lambda qcd we better not screw that +up when we make a change of + + align:start position:0% +up when we make a change of + + + align:start position:0% +up when we make a change of +variable and so + + align:start position:0% + + + + align:start position:0% + +the kind of change of variable you're + + align:start position:0% +the kind of change of variable you're + + + align:start position:0% +the kind of change of variable you're +making is you're taking the original + + align:start position:0% +making is you're taking the original + + + align:start position:0% +making is you're taking the original +Matrix element you're subtracting a + + align:start position:0% +Matrix element you're subtracting a + + + align:start position:0% +Matrix element you're subtracting a +series with the proportionality constant + + align:start position:0% +series with the proportionality constant + + + align:start position:0% +series with the proportionality constant +R zero this guy was Lambda qcd s and you + + align:start position:0% +R zero this guy was Lambda qcd s and you + + + align:start position:0% +R zero this guy was Lambda qcd s and you +you want this to be not too far + + align:start position:0% +you want this to be not too far + + + align:start position:0% +you want this to be not too far +different than Lambda qcd so that this + + align:start position:0% +different than Lambda qcd so that this + + + align:start position:0% +different than Lambda qcd so that this +whole thing here is Lambda qcd Cub just + + align:start position:0% +whole thing here is Lambda qcd Cub just + + + align:start position:0% +whole thing here is Lambda qcd Cub just +like this so that this + + align:start position:0% +like this so that this + + + align:start position:0% +like this so that this +thing is still of order Lambda qcd cubed + + align:start position:0% +thing is still of order Lambda qcd cubed + + + align:start position:0% +thing is still of order Lambda qcd cubed +so you don't want to do something like + + align:start position:0% +so you don't want to do something like + + + align:start position:0% +so you don't want to do something like +choose the r0 to be you know MB or + + align:start position:0% +choose the r0 to be you know MB or + + + align:start position:0% +choose the r0 to be you know MB or +something because then you'd be making a + + align:start position:0% +something because then you'd be making a + + + align:start position:0% +something because then you'd be making a +huge change in the value of this Matrix + + align:start position:0% +huge change in the value of this Matrix + + + align:start position:0% +huge change in the value of this Matrix +element you really want to take the r0o + + align:start position:0% +element you really want to take the r0o + + + align:start position:0% +element you really want to take the r0o +cut off to be of order say a GV or + + align:start position:0% + + + + align:start position:0% + +something so you can use the RG to sum + + align:start position:0% +something so you can use the RG to sum + + + align:start position:0% +something so you can use the RG to sum +up logs from that scale R zero up to the + + align:start position:0% +up logs from that scale R zero up to the + + + align:start position:0% +up logs from that scale R zero up to the +scale of + + align:start position:0% + + + + align:start position:0% + +mq so again we can sum up logs and have + + align:start position:0% +mq so again we can sum up logs and have + + + align:start position:0% +mq so again we can sum up logs and have +a logarithmically + + align:start position:0% +a logarithmically + + + align:start position:0% +a logarithmically +improved result + + align:start position:0% + + + + align:start position:0% + +but actually the most important thing + + align:start position:0% +but actually the most important thing + + + align:start position:0% +but actually the most important thing +here is getting rid of the normal on I + + align:start position:0% +here is getting rid of the normal on I + + + align:start position:0% +here is getting rid of the normal on I +still I want just wanted to kind of show + + align:start position:0% +still I want just wanted to kind of show + + + align:start position:0% +still I want just wanted to kind of show +you what the result would look like with + + align:start position:0% +you what the result would look like with + + + align:start position:0% +you what the result would look like with +both the RG + + align:start position:0% + + + + align:start position:0% + +Improvement just sort of using the full + + align:start position:0% +Improvement just sort of using the full + + + align:start position:0% +Improvement just sort of using the full +set of tools that we + + align:start position:0% +set of tools that we + + + align:start position:0% +set of tools that we +have so here's the scales you have three + + align:start position:0% +have so here's the scales you have three + + + align:start position:0% +have so here's the scales you have three +physical scales bork Mass charm Mass + + align:start position:0% +physical scales bork Mass charm Mass + + + align:start position:0% +physical scales bork Mass charm Mass +Lambda qcd you have two cut offs you + + align:start position:0% +Lambda qcd you have two cut offs you + + + align:start position:0% +Lambda qcd you have two cut offs you +have r0 which I just told you you should + + align:start position:0% +have r0 which I just told you you should + + + align:start position:0% +have r0 which I just told you you should +pick to be close to Lambda Q CD and then + + align:start position:0% +pick to be close to Lambda Q CD and then + + + align:start position:0% +pick to be close to Lambda Q CD and then +you could think that you that there's + + align:start position:0% +you could think that you that there's + + + align:start position:0% +you could think that you that there's +these other scales MB and M charm and + + align:start position:0% +these other scales MB and M charm and + + + align:start position:0% +these other scales MB and M charm and +you'd like to if this is some low scale + + align:start position:0% +you'd like to if this is some low scale + + + align:start position:0% +you'd like to if this is some low scale +and that's some high scale I'd like to + + align:start position:0% +and that's some high scale I'd like to + + + align:start position:0% +and that's some high scale I'd like to +sum logs and I can do that by running up + + align:start position:0% +sum logs and I can do that by running up + + + align:start position:0% +sum logs and I can do that by running up +from r0 to + + align:start position:0% +from r0 to + + + align:start position:0% +from r0 to +R1 which in this case I'll just pick + + align:start position:0% +R1 which in this case I'll just pick + + + align:start position:0% +R1 which in this case I'll just pick +between MB andm + + align:start position:0% +between MB andm + + + align:start position:0% +between MB andm +charm so if you did + + align:start position:0% + + + + align:start position:0% + +that you'd get some result that looks + + align:start position:0% +that you'd get some result that looks + + + align:start position:0% +that you'd get some result that looks +like this + + align:start position:0% + + + + align:start position:0% + +just putting in some notation for the + + align:start position:0% +just putting in some notation for the + + + align:start position:0% +just putting in some notation for the +resummation + + align:start position:0% + + + + align:start position:0% + +here and then this guy is at the low + + align:start position:0% + + + + align:start position:0% + +scale okay so now everybody's happy the + + align:start position:0% +scale okay so now everybody's happy the + + + align:start position:0% +scale okay so now everybody's happy the +Wilson coefficients here can be expanded + + align:start position:0% +Wilson coefficients here can be expanded + + + align:start position:0% +Wilson coefficients here can be expanded +in privation theory we don't think + + align:start position:0% +in privation theory we don't think + + + align:start position:0% +in privation theory we don't think +there's any large logs + + align:start position:0% +there's any large logs + + + align:start position:0% +there's any large logs +this U sums up any large logs between + + align:start position:0% +this U sums up any large logs between + + + align:start position:0% +this U sums up any large logs between +the low scales and the high scales and + + align:start position:0% +the low scales and the high scales and + + + align:start position:0% +the low scales and the high scales and +this guy's living at a scale that he + + align:start position:0% +this guy's living at a scale that he + + + align:start position:0% +this guy's living at a scale that he +likes to live at okay and there's no re + + align:start position:0% +likes to live at okay and there's no re + + + align:start position:0% +likes to live at okay and there's no re +normal one no U equals one R normal one + + align:start position:0% +normal one no U equals one R normal one + + + align:start position:0% +normal one no U equals one R normal one +so what does it look like if I write + + align:start position:0% +so what does it look like if I write + + + align:start position:0% +so what does it look like if I write +down this + + align:start position:0% +down this + + + align:start position:0% +down this +guy so first of all if I look at this + + align:start position:0% +guy so first of all if I look at this + + + align:start position:0% +guy so first of all if I look at this +thing order by order this is how the + + align:start position:0% +thing order by order this is how the + + + align:start position:0% +thing order by order this is how the +convergent convergence looks you get a + + align:start position:0% +convergent convergence looks you get a + + + align:start position:0% +convergent convergence looks you get a +downward shift by about the same amount + + align:start position:0% +downward shift by about the same amount + + + align:start position:0% +downward shift by about the same amount +as before but the next shifts are small + + align:start position:0% +as before but the next shifts are small + + + align:start position:0% +as before but the next shifts are small +so the series actually looks like it's + + align:start position:0% +so the series actually looks like it's + + + align:start position:0% +so the series actually looks like it's +converging to + + align:start position:0% +converging to + + + align:start position:0% +converging to +something so that's the first three + + align:start position:0% +something so that's the first three + + + align:start position:0% +something so that's the first three +orders if you use this + + align:start position:0% +orders if you use this + + + align:start position:0% +orders if you use this +approach and if you use the complete + + align:start position:0% +approach and if you use the complete + + + align:start position:0% +approach and if you use the complete +power of this at the highest + + align:start position:0% + + + + align:start position:0% + +order you can write + + align:start position:0% +order you can write + + + align:start position:0% +order you can write +down that you get this 860 from the + + align:start position:0% +down that you get this 860 from the + + + align:start position:0% +down that you get this 860 from the +perative part which is not too far from + + align:start position:0% +perative part which is not too far from + + + align:start position:0% +perative part which is not too far from +the 088 or the 8517 which I said was + + align:start position:0% +the 088 or the 8517 which I said was + + + align:start position:0% +the 088 or the 8517 which I said was +close to the data okay so this actually + + align:start position:0% +close to the data okay so this actually + + + align:start position:0% +close to the data okay so this actually +is pretty good + + align:start position:0% +is pretty good + + + align:start position:0% +is pretty good +you can make some air estimate for how + + align:start position:0% +you can make some air estimate for how + + + align:start position:0% +you can make some air estimate for how +big this thing + + align:start position:0% + + + + align:start position:0% + +is and you can make some error estimate + + align:start position:0% +is and you can make some error estimate + + + align:start position:0% +is and you can make some error estimate +for the perturbative uncertainty from + + align:start position:0% +for the perturbative uncertainty from + + + align:start position:0% +for the perturbative uncertainty from +higher orders by varying + + align:start position:0% +higher orders by varying + + + align:start position:0% +higher orders by varying +scales and you get with a prediction + + align:start position:0% +scales and you get with a prediction + + + align:start position:0% +scales and you get with a prediction +that looks like + + align:start position:0% +that looks like + + + align:start position:0% +that looks like +that so when you want to estimate + + align:start position:0% +that so when you want to estimate + + + align:start position:0% +that so when you want to estimate +uncertainties what you typically do with + + align:start position:0% +uncertainties what you typically do with + + + align:start position:0% +uncertainties what you typically do with +your cut off is you vary them you say + + align:start position:0% +your cut off is you vary them you say + + + align:start position:0% +your cut off is you vary them you say +Well it has to be up here but I don't + + align:start position:0% +Well it has to be up here but I don't + + + align:start position:0% +Well it has to be up here but I don't +have to take take it exactly there I + + align:start position:0% +have to take take it exactly there I + + + align:start position:0% +have to take take it exactly there I +could take it up here take it a little + + align:start position:0% +could take it up here take it a little + + + align:start position:0% +could take it up here take it a little +lower move this guy around that gives + + align:start position:0% +lower move this guy around that gives + + + align:start position:0% +lower move this guy around that gives +you some idea of higher order + + align:start position:0% +you some idea of higher order + + + align:start position:0% +you some idea of higher order +uncertainties because the dependence on + + align:start position:0% +uncertainties because the dependence on + + + align:start position:0% +uncertainties because the dependence on +these scales cancels out order by order + + align:start position:0% +these scales cancels out order by order + + + align:start position:0% +these scales cancels out order by order +and peration theory and so varying it um + + align:start position:0% +and peration theory and so varying it um + + + align:start position:0% +and peration theory and so varying it um +is a way of getting an idea of higher + + align:start position:0% +is a way of getting an idea of higher + + + align:start position:0% +is a way of getting an idea of higher +order uncertainties from peration Theory + + align:start position:0% +order uncertainties from peration Theory + + + align:start position:0% +order uncertainties from peration Theory +and that's what I've done for example + + align:start position:0% +and that's what I've done for example + + + align:start position:0% +and that's what I've done for example +for this perative term here this is + + align:start position:0% +for this perative term here this is + + + align:start position:0% +for this perative term here this is +varying + + align:start position:0% +varying + + + align:start position:0% +varying +R1 up and down by a factor of two and + + align:start position:0% +R1 up and down by a factor of two and + + + align:start position:0% +R1 up and down by a factor of two and +just see kind of what residual + + align:start position:0% +just see kind of what residual + + + align:start position:0% +just see kind of what residual +uncertainty you have this one's more + + align:start position:0% +uncertainty you have this one's more + + + align:start position:0% +uncertainty you have this one's more +interesting so one's like mu variation + + align:start position:0% +interesting so one's like mu variation + + + align:start position:0% +interesting so one's like mu variation +this one's more interesting and that's + + align:start position:0% +this one's more interesting and that's + + + align:start position:0% +this one's more interesting and that's +because we have this other cut off r0 + + align:start position:0% +because we have this other cut off r0 + + + align:start position:0% +because we have this other cut off r0 +but what r0 does is it connects a + + align:start position:0% +but what r0 does is it connects a + + + align:start position:0% +but what r0 does is it connects a +leading order term to a subleading power + + align:start position:0% +leading order term to a subleading power + + + align:start position:0% +leading order term to a subleading power +term the r0o dependence cancels between + + align:start position:0% +term the r0o dependence cancels between + + + align:start position:0% +term the r0o dependence cancels between +something that's order one in the power + + align:start position:0% +something that's order one in the power + + + align:start position:0% +something that's order one in the power +counting something that's higher order + + align:start position:0% +counting something that's higher order + + + align:start position:0% +counting something that's higher order +in the power + + align:start position:0% +in the power + + + align:start position:0% +in the power +counting but when I vary r0o it still + + align:start position:0% +counting but when I vary r0o it still + + + align:start position:0% +counting but when I vary r0o it still +cancels between these two pieces because + + align:start position:0% +cancels between these two pieces because + + + align:start position:0% +cancels between these two pieces because +remember I've included in if you look at + + align:start position:0% +remember I've included in if you look at + + + align:start position:0% +remember I've included in if you look at +the top of the board I've included + + align:start position:0% +the top of the board I've included + + + align:start position:0% +the top of the board I've included +higher power terms in my Wilson + + align:start position:0% +higher power terms in my Wilson + + + align:start position:0% +higher power terms in my Wilson +coefficient + + align:start position:0% +coefficient + + + align:start position:0% +coefficient +and so varying the r0 you can actually + + align:start position:0% +and so varying the r0 you can actually + + + align:start position:0% +and so varying the r0 you can actually +get an idea of how big this thing is + + align:start position:0% +get an idea of how big this thing is + + + align:start position:0% +get an idea of how big this thing is +kind of in a naive dimensional analysis + + align:start position:0% +kind of in a naive dimensional analysis + + + align:start position:0% +kind of in a naive dimensional analysis +type way and that gives this number + + align:start position:0% +type way and that gives this number + + + align:start position:0% +type way and that gives this number +here so r0o variation actually allows + + align:start position:0% +here so r0o variation actually allows + + + align:start position:0% +here so r0o variation actually allows +you to test for the size of power + + align:start position:0% +you to test for the size of power + + + align:start position:0% +you to test for the size of power +Corrections if you don't know + + align:start position:0% +Corrections if you don't know + + + align:start position:0% +Corrections if you don't know +them and in this case it turns out that + + align:start position:0% +them and in this case it turns out that + + + align:start position:0% +them and in this case it turns out that +the power correction is kind of small in + + align:start position:0% +the power correction is kind of small in + + + align:start position:0% +the power correction is kind of small in +this scheme but didn't have to be that + + align:start position:0% +this scheme but didn't have to be that + + + align:start position:0% +this scheme but didn't have to be that +small it could have been 165 + + align:start position:0% +small it could have been 165 + + + align:start position:0% +small it could have been 165 +265 happens to be + + align:start position:0% +265 happens to be + + + align:start position:0% +265 happens to be +0065 okay so everything looks much nicer + + align:start position:0% +0065 okay so everything looks much nicer + + + align:start position:0% +0065 okay so everything looks much nicer +after we get just get rid of the re + + align:start position:0% +after we get just get rid of the re + + + align:start position:0% +after we get just get rid of the re +normal one someone else did the + + align:start position:0% +normal one someone else did the + + + align:start position:0% +normal one someone else did the +three-loop calculation you made the + + align:start position:0% + + + + align:start position:0% + +prediction just true in this + + align:start position:0% + + + + align:start position:0% + +case Okay so + + align:start position:0% + + + + align:start position:0% + +questions + + align:start position:0% +questions + + + align:start position:0% +questions +so the moral of the story is that if you + + align:start position:0% +so the moral of the story is that if you + + + align:start position:0% +so the moral of the story is that if you +really want to use calculations that are + + align:start position:0% +really want to use calculations that are + + + align:start position:0% +really want to use calculations that are +out there and you you have to think + + align:start position:0% +out there and you you have to think + + + align:start position:0% +out there and you you have to think +about the physics you can't just + + align:start position:0% +about the physics you can't just + + + align:start position:0% +about the physics you can't just +calculate + + align:start position:0% + + + + align:start position:0% + +sorry okay so these were normal lines + + align:start position:0% +sorry okay so these were normal lines + + + align:start position:0% +sorry okay so these were normal lines +when you have kind of order alpha squ or + + align:start position:0% +when you have kind of order alpha squ or + + + align:start position:0% +when you have kind of order alpha squ or +Alpha cubed information then you have to + + align:start position:0% +Alpha cubed information then you have to + + + align:start position:0% +Alpha cubed information then you have to +worry about things like this and if you + + align:start position:0% +worry about things like this and if you + + + align:start position:0% +worry about things like this and if you +didn't what looked like was working + + align:start position:0% +didn't what looked like was working + + + align:start position:0% +didn't what looked like was working +beautifully at leading log order might + + align:start position:0% +beautifully at leading log order might + + + align:start position:0% +beautifully at leading log order might +get + + align:start position:0% +get + + + align:start position:0% +get +spoiled your leading log might be the + + align:start position:0% +spoiled your leading log might be the + + + align:start position:0% +spoiled your leading log might be the +best prediction unless you think about + + align:start position:0% +best prediction unless you think about + + + align:start position:0% +best prediction unless you think about +this that you can make because you're + + align:start position:0% +this that you can make because you're + + + align:start position:0% +this that you can make because you're +just higher orders you're getting + + align:start position:0% +just higher orders you're getting + + + align:start position:0% +just higher orders you're getting +sensitive to this normal on problem + + align:start position:0% +sensitive to this normal on problem + + + align:start position:0% +sensitive to this normal on problem +and that what that means is + + align:start position:0% +and that what that means is + + + align:start position:0% +and that what that means is +generically this is changing and this is + + align:start position:0% +generically this is changing and this is + + + align:start position:0% +generically this is changing and this is +changing the power correction is + + align:start position:0% +changing the power correction is + + + align:start position:0% +changing the power correction is +changing and so at each order that this + + align:start position:0% +changing and so at each order that this + + + align:start position:0% +changing and so at each order that this +changes I could compensate by changing + + align:start position:0% +changes I could compensate by changing + + + align:start position:0% +changes I could compensate by changing +this but it would have to be a pretty + + align:start position:0% +this but it would have to be a pretty + + + align:start position:0% +this but it would have to be a pretty +big change right I change this guy by + + align:start position:0% +big change right I change this guy by + + + align:start position:0% +big change right I change this guy by +this amount then I have to compensate by + + align:start position:0% +this amount then I have to compensate by + + + align:start position:0% +this amount then I have to compensate by +that oop now it even changes by a larger + + align:start position:0% +that oop now it even changes by a larger + + + align:start position:0% +that oop now it even changes by a larger +amount well compensate by changing this + + align:start position:0% +amount well compensate by changing this + + + align:start position:0% +amount well compensate by changing this +by order one amount that's exactly this + + align:start position:0% +by order one amount that's exactly this + + + align:start position:0% +by order one amount that's exactly this +this fact that both things have this + + align:start position:0% +this fact that both things have this + + + align:start position:0% +this fact that both things have this +problem order by order I can cancel out + + align:start position:0% +problem order by order I can cancel out + + + align:start position:0% +problem order by order I can cancel out +the problem by but I don't want but then + + align:start position:0% +the problem by but I don't want but then + + + align:start position:0% +the problem by but I don't want but then +I can never really assign a number to + + align:start position:0% +I can never really assign a number to + + + align:start position:0% +I can never really assign a number to +this it's an order dependent number each + + align:start position:0% +this it's an order dependent number each + + + align:start position:0% +this it's an order dependent number each +order in peration theory that I use here + + align:start position:0% +order in peration theory that I use here + + + align:start position:0% +order in peration theory that I use here +this number changes and that's not + + align:start position:0% +this number changes and that's not + + + align:start position:0% +this number changes and that's not +really what you think of for a physical + + align:start position:0% +really what you think of for a physical + + + align:start position:0% +really what you think of for a physical +concept that this Matrix element should + + align:start position:0% +concept that this Matrix element should + + + align:start position:0% +concept that this Matrix element should +have a meaning that it it shouldn't be + + align:start position:0% +have a meaning that it it shouldn't be + + + align:start position:0% +have a meaning that it it shouldn't be +changing by order one depending on the + + align:start position:0% +changing by order one depending on the + + + align:start position:0% +changing by order one depending on the +perturbative order that you're working + + align:start position:0% +perturbative order that you're working + + + align:start position:0% +perturbative order that you're working +in this way of thinking this thing is + + align:start position:0% +in this way of thinking this thing is + + + align:start position:0% +in this way of thinking this thing is +stable much more stable anyway and you + + align:start position:0% +stable much more stable anyway and you + + + align:start position:0% +stable much more stable anyway and you +can assign a number to + + align:start position:0% +can assign a number to + + + align:start position:0% +can assign a number to +it that's kind of the + + align:start position:0% +it that's kind of the + + + align:start position:0% +it that's kind of the +moral all right + + align:start position:0% + + + + align:start position:0% + +yeah so the thing is that the + + align:start position:0% +yeah so the thing is that the + + + align:start position:0% +yeah so the thing is that the +convergence it's not about the Precision + + align:start position:0% +convergence it's not about the Precision + + + align:start position:0% +convergence it's not about the Precision +it's about the + + align:start position:0% +it's about the + + + align:start position:0% +it's about the +convergence right so you would be fine + + align:start position:0% +convergence right so you would be fine + + + align:start position:0% +convergence right so you would be fine +in some sense it would not be + + align:start position:0% +in some sense it would not be + + + align:start position:0% +in some sense it would not be +technically a problem if this was + + align:start position:0% +technically a problem if this was + + + align:start position:0% +technically a problem if this was +zero right if this guy was that much of + + align:start position:0% +zero right if this guy was that much of + + + align:start position:0% +zero right if this guy was that much of +a + + align:start position:0% +a + + + align:start position:0% +a +shift and well this this was a 15 shift + + align:start position:0% +shift and well this this was a 15 shift + + + align:start position:0% +shift and well this this was a 15 shift +this is a seven shift if this guy was + + align:start position:0% +this is a seven shift if this guy was + + + align:start position:0% +this is a seven shift if this guy was +like small again you'd be fine + + align:start position:0% +like small again you'd be fine + + + align:start position:0% +like small again you'd be fine +right because then you'd say okay well I + + align:start position:0% +right because then you'd say okay well I + + + align:start position:0% +right because then you'd say okay well I +extract this thing in the same order + + align:start position:0% +extract this thing in the same order + + + align:start position:0% +extract this thing in the same order +that I include that and you know and + + align:start position:0% +that I include that and you know and + + + align:start position:0% +that I include that and you know and +maybe this thing gives a plus 07 and + + align:start position:0% +maybe this thing gives a plus 07 and + + + align:start position:0% +maybe this thing gives a plus 07 and +this guy gives Aus 07 and then I'm close + + align:start position:0% +this guy gives Aus 07 and then I'm close + + + align:start position:0% +this guy gives Aus 07 and then I'm close +to the data and you're happy the issue + + align:start position:0% +to the data and you're happy the issue + + + align:start position:0% +to the data and you're happy the issue +is that you go to a higher order and you + + align:start position:0% +is that you go to a higher order and you + + + align:start position:0% +is that you go to a higher order and you +get even bigger shift that's the real + + align:start position:0% +get even bigger shift that's the real + + + align:start position:0% +get even bigger shift that's the real +real problem that you don't in the + + align:start position:0% +real problem that you don't in the + + + align:start position:0% +real problem that you don't in the +perturbative part alone have any sign of + + align:start position:0% +perturbative part alone have any sign of + + + align:start position:0% +perturbative part alone have any sign of +convergence that's the issue it's not so + + align:start position:0% +convergence that's the issue it's not so + + + align:start position:0% +convergence that's the issue it's not so +the fact that this number is sort of + + align:start position:0% +the fact that this number is sort of + + + align:start position:0% +the fact that this number is sort of +close to that number is you know in some + + align:start position:0% +close to that number is you know in some + + + align:start position:0% +close to that number is you know in some +sense okay because you think that this + + align:start position:0% +sense okay because you think that this + + + align:start position:0% +sense okay because you think that this +thing should generically be of that size + + align:start position:0% +thing should generically be of that size + + + align:start position:0% +thing should generically be of that size +that's what dimensional analysis would + + align:start position:0% +that's what dimensional analysis would + + + align:start position:0% +that's what dimensional analysis would +say dimensional analysis might even say + + align:start position:0% +say dimensional analysis might even say + + + align:start position:0% +say dimensional analysis might even say +it's a little + + align:start position:0% +it's a little + + + align:start position:0% +it's a little +bigger um so the real issue is that you + + align:start position:0% +bigger um so the real issue is that you + + + align:start position:0% +bigger um so the real issue is that you +want your predictions to be + + align:start position:0% +want your predictions to be + + + align:start position:0% +want your predictions to be +stable and + + align:start position:0% +stable and + + + align:start position:0% +stable and +yeah be higher than so this now this + + align:start position:0% +yeah be higher than so this now this + + + align:start position:0% +yeah be higher than so this now this +this actually here is connected to that + + align:start position:0% +this actually here is connected to that + + + align:start position:0% +this actually here is connected to that +term I'm saying even if I leave this + + align:start position:0% +term I'm saying even if I leave this + + + align:start position:0% +term I'm saying even if I leave this +term out I actually get something that + + align:start position:0% +term out I actually get something that + + + align:start position:0% +term out I actually get something that +agrees with the data + + align:start position:0% +agrees with the data + + + align:start position:0% +agrees with the data +and that's because it turns out that the + + align:start position:0% +and that's because it turns out that the + + + align:start position:0% +and that's because it turns out that the +power correction here is you know of + + align:start position:0% +power correction here is you know of + + + align:start position:0% +power correction here is you know of +this size and I can get an idea of how + + align:start position:0% +this size and I can get an idea of how + + + align:start position:0% +this size and I can get an idea of how +big it is by varying the r0o in this + + align:start position:0% +big it is by varying the r0o in this + + + align:start position:0% +big it is by varying the r0o in this +prediction and that changes this number + + align:start position:0% +prediction and that changes this number + + + align:start position:0% +prediction and that changes this number +by that amount and that's I and since + + align:start position:0% +by that amount and that's I and since + + + align:start position:0% +by that amount and that's I and since +this thing is also changing in exactly a + + align:start position:0% +this thing is also changing in exactly a + + + align:start position:0% +this thing is also changing in exactly a +way that compensates that R zero + + align:start position:0% +way that compensates that R zero + + + align:start position:0% +way that compensates that R zero +dependence I'm getting an estimate for + + align:start position:0% +dependence I'm getting an estimate for + + + align:start position:0% +dependence I'm getting an estimate for +this thing that's what I did there so if + + align:start position:0% +this thing that's what I did there so if + + + align:start position:0% +this thing that's what I did there so if +I were to put this thing in I'd have a + + align:start position:0% +I were to put this thing in I'd have a + + + align:start position:0% +I were to put this thing in I'd have a +new parameter and I could exactly fit + + align:start position:0% +new parameter and I could exactly fit + + + align:start position:0% +new parameter and I could exactly fit +the data right but I did it I wrote what + + align:start position:0% +the data right but I did it I wrote what + + + align:start position:0% +the data right but I did it I wrote what +I wrote was a little different + + align:start position:0% + + + + align:start position:0% + +yeah I kind of went over that + + align:start position:0% +yeah I kind of went over that + + + align:start position:0% +yeah I kind of went over that +quickly all right + + align:start position:0% +quickly all right + + + align:start position:0% +quickly all right +so that's actually it for + + align:start position:0% + + + + align:start position:0% + +HQ so before we get to se which is + + align:start position:0% +HQ so before we get to se which is + + + align:start position:0% +HQ so before we get to se which is +coming up after spring + + align:start position:0% +coming up after spring + + + align:start position:0% +coming up after spring +break we're going to talk about one more + + align:start position:0% + + + + align:start position:0% + +topic which I'll just basically + + align:start position:0% +topic which I'll just basically + + + align:start position:0% +topic which I'll just basically +introduce and then we'll stop and + + align:start position:0% +introduce and then we'll stop and + + + align:start position:0% +introduce and then we'll stop and +continue on + + align:start position:0% + + + + align:start position:0% + +Thursday so there's going to be one more + + align:start position:0% +Thursday so there's going to be one more + + + align:start position:0% +Thursday so there's going to be one more +example of an effective field + + align:start position:0% +example of an effective field + + + align:start position:0% +example of an effective field +Theory and this is going to be an + + align:start position:0% +Theory and this is going to be an + + + align:start position:0% +Theory and this is going to be an +example of an effective field Theory + + align:start position:0% +example of an effective field Theory + + + align:start position:0% +example of an effective field Theory +with what looks like a problem it's got + + align:start position:0% +with what looks like a problem it's got + + + align:start position:0% +with what looks like a problem it's got +a fine + + align:start position:0% +a fine + + + align:start position:0% +a fine +tuning so usually the whole notion of + + align:start position:0% +tuning so usually the whole notion of + + + align:start position:0% +tuning so usually the whole notion of +effective field theory is against the + + align:start position:0% +effective field theory is against the + + + align:start position:0% +effective field theory is against the +idea that there should be a fine tuning + + align:start position:0% +idea that there should be a fine tuning + + + align:start position:0% +idea that there should be a fine tuning +because you're making an dimensional + + align:start position:0% +because you're making an dimensional + + + align:start position:0% +because you're making an dimensional +analysis estimates of things if there's + + align:start position:0% +analysis estimates of things if there's + + + align:start position:0% +analysis estimates of things if there's +a fine tuning that means you're + + align:start position:0% +a fine tuning that means you're + + + align:start position:0% +a fine tuning that means you're +dimensional analysis failed in this + + align:start position:0% +dimensional analysis failed in this + + + align:start position:0% +dimensional analysis failed in this +example we'll see that you can make one + + align:start position:0% +example we'll see that you can make one + + + align:start position:0% +example we'll see that you can make one +fine tuning and you can understand + + align:start position:0% +fine tuning and you can understand + + + align:start position:0% +fine tuning and you can understand +what's going on with that fine tuning + + align:start position:0% +what's going on with that fine tuning + + + align:start position:0% +what's going on with that fine tuning +and actually propagate it to change your + + align:start position:0% +and actually propagate it to change your + + + align:start position:0% +and actually propagate it to change your +power counting to change your power + + align:start position:0% +power counting to change your power + + + align:start position:0% +power counting to change your power +counting such that it takes into account + + align:start position:0% +counting such that it takes into account + + + align:start position:0% +counting such that it takes into account +the existence of that fine tuning builds + + align:start position:0% +the existence of that fine tuning builds + + + align:start position:0% +the existence of that fine tuning builds +the whole defective theory around the + + align:start position:0% +the whole defective theory around the + + + align:start position:0% +the whole defective theory around the +idea that there was this fine tuning + + align:start position:0% +idea that there was this fine tuning + + + align:start position:0% +idea that there was this fine tuning +from an original perhaps Dimension + + align:start position:0% +from an original perhaps Dimension + + + align:start position:0% +from an original perhaps Dimension +counting point of view but that we can + + align:start position:0% +counting point of view but that we can + + + align:start position:0% +counting point of view but that we can +adopt a different Power counting that + + align:start position:0% +adopt a different Power counting that + + + align:start position:0% +adopt a different Power counting that +actually organizes the physics in + + align:start position:0% +actually organizes the physics in + + + align:start position:0% +actually organizes the physics in +exactly the right way that we want to + + align:start position:0% +exactly the right way that we want to + + + align:start position:0% +exactly the right way that we want to +and in fact it's going to be such an + + align:start position:0% +and in fact it's going to be such an + + + align:start position:0% +and in fact it's going to be such an +easy example where we we can just + + align:start position:0% +easy example where we we can just + + + align:start position:0% +easy example where we we can just +basically calculate all the fan diagrams + + align:start position:0% +basically calculate all the fan diagrams + + + align:start position:0% +basically calculate all the fan diagrams +like very simply one line um so that's + + align:start position:0% +like very simply one line um so that's + + + align:start position:0% +like very simply one line um so that's +what we'll + + align:start position:0% + + + + align:start position:0% + +do it'll be a very simple example of an + + align:start position:0% +do it'll be a very simple example of an + + + align:start position:0% +do it'll be a very simple example of an +effective the field + + align:start position:0% +effective the field + + + align:start position:0% +effective the field +Theory and we'll prove some things about + + align:start position:0% +Theory and we'll prove some things about + + + align:start position:0% +Theory and we'll prove some things about +quantum mechanics that would be very + + align:start position:0% +quantum mechanics that would be very + + + align:start position:0% +quantum mechanics that would be very +difficult if we weren't + + align:start position:0% +difficult if we weren't + + + align:start position:0% +difficult if we weren't +using effective field Theory along the + + align:start position:0% + + + + align:start position:0% + +way so we'll investigate an effective + + align:start position:0% +way so we'll investigate an effective + + + align:start position:0% +way so we'll investigate an effective +theory that has a naively irrelevant + + align:start position:0% + + + + align:start position:0% + +operator that must be + + align:start position:0% +operator that must be + + + align:start position:0% +operator that must be +promoted to being + + align:start position:0% + + + + align:start position:0% + +relevant so by dimensional analysis it + + align:start position:0% +relevant so by dimensional analysis it + + + align:start position:0% +relevant so by dimensional analysis it +would be irrelevant and one way of + + align:start position:0% +would be irrelevant and one way of + + + align:start position:0% +would be irrelevant and one way of +thinking about it is that it just has + + align:start position:0% +thinking about it is that it just has + + + align:start position:0% +thinking about it is that it just has +such a large anomalous Dimension that it + + align:start position:0% +such a large anomalous Dimension that it + + + align:start position:0% +such a large anomalous Dimension that it +actually ends up being totally + + align:start position:0% +actually ends up being totally + + + align:start position:0% +actually ends up being totally +relevant and that is actually not a bad + + align:start position:0% +relevant and that is actually not a bad + + + align:start position:0% +relevant and that is actually not a bad +way of thinking about + + align:start position:0% +way of thinking about + + + align:start position:0% +way of thinking about +it so the example we'll talk + + align:start position:0% +it so the example we'll talk + + + align:start position:0% +it so the example we'll talk +about is something called two + + align:start position:0% +about is something called two + + + align:start position:0% +about is something called two +nucleon non-relativistic + + align:start position:0% + + + + align:start position:0% + +effective field + + align:start position:0% + + + + align:start position:0% + +Theory so you have two nucleons a + + align:start position:0% +Theory so you have two nucleons a + + + align:start position:0% +Theory so you have two nucleons a +neutron and a proton for example + + align:start position:0% + + + + align:start position:0% + +it's a bottomup effective + + align:start position:0% +it's a bottomup effective + + + align:start position:0% +it's a bottomup effective +Theory we're not going to be thinking + + align:start position:0% +Theory we're not going to be thinking + + + align:start position:0% +Theory we're not going to be thinking +about calculating nucleons in qcd we're + + align:start position:0% +about calculating nucleons in qcd we're + + + align:start position:0% +about calculating nucleons in qcd we're +going to work at momenta that are so + + align:start position:0% +going to work at momenta that are so + + + align:start position:0% +going to work at momenta that are so +small that we actually integrate out the + + align:start position:0% + + + + align:start position:0% + +pon so all exchange particles are + + align:start position:0% +pon so all exchange particles are + + + align:start position:0% +pon so all exchange particles are +integrated out + + align:start position:0% + + + + align:start position:0% + +so there's nothing to exchange and + + align:start position:0% +so there's nothing to exchange and + + + align:start position:0% +so there's nothing to exchange and +really just have contact type + + align:start position:0% +really just have contact type + + + align:start position:0% +really just have contact type +interactions so something that you might + + align:start position:0% +interactions so something that you might + + + align:start position:0% +interactions so something that you might +think of as like a pine exchange between + + align:start position:0% +think of as like a pine exchange between + + + align:start position:0% +think of as like a pine exchange between +two + + align:start position:0% + + + + align:start position:0% + +nucleons that's represented by some + + align:start position:0% +nucleons that's represented by some + + + align:start position:0% +nucleons that's represented by some +local + + align:start position:0% +local + + + align:start position:0% +local +operators between the + + align:start position:0% + + + + align:start position:0% + +nucleons all right so let me stop there + + align:start position:0% +nucleons all right so let me stop there + + + align:start position:0% +nucleons all right so let me stop there +and we'll come back and talk more about + + align:start position:0% +and we'll come back and talk more about + + + align:start position:0% +and we'll come back and talk more about +this Theory next time and we'll see that + + align:start position:0% +this Theory next time and we'll see that + + + align:start position:0% +this Theory next time and we'll see that +we can first that these operators of + + align:start position:0% +we can first that these operators of + + + align:start position:0% +we can first that these operators of +this type actually can organize some + + align:start position:0% +this type actually can organize some + + + align:start position:0% +this type actually can organize some +facts about quantum mechanics in a very + + align:start position:0% +facts about quantum mechanics in a very + + + align:start position:0% +facts about quantum mechanics in a very +nice way and then we'll see how to think + + align:start position:0% +nice way and then we'll see how to think + + + align:start position:0% +nice way and then we'll see how to think +about fine-tuning from this contact + + align:start position:0% +about fine-tuning from this contact + + + align:start position:0% +about fine-tuning from this contact +interaction + + align:start position:0% +interaction + + + align:start position:0% +interaction +Theory and also how to think about sort + + align:start position:0% +Theory and also how to think about sort + + + align:start position:0% +Theory and also how to think about sort +of how we want to organize the power + + align:start position:0% +of how we want to organize the power + + + align:start position:0% +of how we want to organize the power +counting what's msar say + + align:start position:0% + + + + align:start position:0% + +Etc okay it's kind of a fun thing very \ No newline at end of file diff --git a/FCFpaKcpuXQ.txt b/FCFpaKcpuXQ.txt new file mode 100644 index 0000000000000000000000000000000000000000..5421c00b660c96da8037db15e3cd3ccc61e5f373 --- /dev/null +++ b/FCFpaKcpuXQ.txt @@ -0,0 +1,9827 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license + + align:start position:0% +a Creative Commons license + + + align:start position:0% +a Creative Commons license +your support will help MIT + + align:start position:0% +your support will help MIT + + + align:start position:0% +your support will help MIT +OpenCourseWare continue to offer high + + align:start position:0% +OpenCourseWare continue to offer high + + + align:start position:0% +OpenCourseWare continue to offer high +quality educational resources for free + + align:start position:0% +quality educational resources for free + + + align:start position:0% +quality educational resources for free +to make a donation or to view additional + + align:start position:0% +to make a donation or to view additional + + + align:start position:0% +to make a donation or to view additional +materials from hundreds of MIT courses + + align:start position:0% +materials from hundreds of MIT courses + + + align:start position:0% +materials from hundreds of MIT courses +visit MIT opencourseware at ocw.mit.edu + + align:start position:0% + + + + align:start position:0% + +okay so welcome back everybody happy to + + align:start position:0% +okay so welcome back everybody happy to + + + align:start position:0% +okay so welcome back everybody happy to +see you again so today we are going to + + align:start position:0% +see you again so today we are going to + + + align:start position:0% +see you again so today we are going to +continue our exploration and understand + + align:start position:0% +continue our exploration and understand + + + align:start position:0% +continue our exploration and understand +a single harmonic oscillator and this is + + align:start position:0% +a single harmonic oscillator and this is + + + align:start position:0% +a single harmonic oscillator and this is +actually our list of our goals and we + + align:start position:0% +actually our list of our goals and we + + + align:start position:0% +actually our list of our goals and we +would like to learn how to translate + + align:start position:0% +would like to learn how to translate + + + align:start position:0% +would like to learn how to translate +physical situations into mathematics so + + align:start position:0% +physical situations into mathematics so + + + align:start position:0% +physical situations into mathematics so +that we can actually solve the physical + + align:start position:0% +that we can actually solve the physical + + + align:start position:0% +that we can actually solve the physical +problems we actually have and predict + + align:start position:0% +problems we actually have and predict + + + align:start position:0% +problems we actually have and predict +what is going to happen up to work and + + align:start position:0% +what is going to happen up to work and + + + align:start position:0% +what is going to happen up to work and +we also sort of started to this course + + align:start position:0% +we also sort of started to this course + + + align:start position:0% +we also sort of started to this course +by solving really simple examples single + + align:start position:0% +by solving really simple examples single + + + align:start position:0% +by solving really simple examples single +harmonic oscillators and as a function + + align:start position:0% +harmonic oscillators and as a function + + + align:start position:0% +harmonic oscillators and as a function +of time you will see that from next + + align:start position:0% +of time you will see that from next + + + align:start position:0% +of time you will see that from next +class the next lecture we are going to + + align:start position:0% +class the next lecture we are going to + + + align:start position:0% +class the next lecture we are going to +bring in more and more objects and of + + align:start position:0% +bring in more and more objects and of + + + align:start position:0% +bring in more and more objects and of +course more of just means more + + align:start position:0% +course more of just means more + + + align:start position:0% +course more of just means more +excitement also in terms of phenomena + + align:start position:0% +excitement also in terms of phenomena + + + align:start position:0% +excitement also in terms of phenomena +were also more complication on the + + align:start position:0% +were also more complication on the + + + align:start position:0% +were also more complication on the +mathematics so so we will see what how + + align:start position:0% +mathematics so so we will see what how + + + align:start position:0% +mathematics so so we will see what how +things goes and then after that we are + + align:start position:0% +things goes and then after that we are + + + align:start position:0% +things goes and then after that we are +going to go to infinite number of + + align:start position:0% +going to go to infinite number of + + + align:start position:0% +going to go to infinite number of +oscillators and to see what happen of + + align:start position:0% +oscillators and to see what happen of + + + align:start position:0% +oscillators and to see what happen of +course we will produce waves that's very + + align:start position:0% +course we will produce waves that's very + + + align:start position:0% +course we will produce waves that's very +exciting then we'll do all kinds of + + align:start position:0% +exciting then we'll do all kinds of + + + align:start position:0% +exciting then we'll do all kinds of +different tricks to to those waves okay + + align:start position:0% +different tricks to to those waves okay + + + align:start position:0% +different tricks to to those waves okay +so what we have we learned last time so + + align:start position:0% +so what we have we learned last time so + + + align:start position:0% +so what we have we learned last time so +last time we hang over example a simple + + align:start position:0% +last time we hang over example a simple + + + align:start position:0% +last time we hang over example a simple +harmonic oscillator it says your rod + + align:start position:0% +harmonic oscillator it says your rod + + + align:start position:0% +harmonic oscillator it says your rod +fixed on the wall and you can actually + + align:start position:0% +fixed on the wall and you can actually + + + align:start position:0% +fixed on the wall and you can actually +go back and forth and we also introduced + + align:start position:0% +go back and forth and we also introduced + + + align:start position:0% +go back and forth and we also introduced +a model of the drag force or track + + align:start position:0% +a model of the drag force or track + + + align:start position:0% +a model of the drag force or track +torque and this is actually proportional + + align:start position:0% +torque and this is actually proportional + + + align:start position:0% +torque and this is actually proportional +to the velocity of the motion of the + + align:start position:0% +to the velocity of the motion of the + + + align:start position:0% +to the velocity of the motion of the +single particle and the interesting + + align:start position:0% +single particle and the interesting + + + align:start position:0% +single particle and the interesting +thing we learned last time is that we + + align:start position:0% +thing we learned last time is that we + + + align:start position:0% +thing we learned last time is that we +have three + + align:start position:0% +have three + + + align:start position:0% +have three +completely different behaviors if we + + align:start position:0% +completely different behaviors if we + + + align:start position:0% +completely different behaviors if we +actually turn on the track force the + + align:start position:0% +actually turn on the track force the + + + align:start position:0% +actually turn on the track force the +first one is under damped the temp temp + + align:start position:0% +first one is under damped the temp temp + + + align:start position:0% +first one is under damped the temp temp +in usage is very small then we have the + + align:start position:0% +in usage is very small then we have the + + + align:start position:0% +in usage is very small then we have the +solution in this form is oscillating the + + align:start position:0% +solution in this form is oscillating the + + + align:start position:0% +solution in this form is oscillating the +amplitude is decaying exponentially and + + align:start position:0% +amplitude is decaying exponentially and + + + align:start position:0% +amplitude is decaying exponentially and +we as we increase and greet as we make + + align:start position:0% +we as we increase and greet as we make + + + align:start position:0% +we as we increase and greet as we make +the drag force larger and larger you + + align:start position:0% +the drag force larger and larger you + + + align:start position:0% +the drag force larger and larger you +will pass a critical point which + + align:start position:0% +will pass a critical point which + + + align:start position:0% +will pass a critical point which +actually give you a solution which you + + align:start position:0% +actually give you a solution which you + + + align:start position:0% +actually give you a solution which you +don't have oscillation anymore the + + align:start position:0% +don't have oscillation anymore the + + + align:start position:0% +don't have oscillation anymore the +cosine disappeared finally if you use + + align:start position:0% +cosine disappeared finally if you use + + + align:start position:0% +cosine disappeared finally if you use +you actually put a whole system into + + align:start position:0% +you actually put a whole system into + + + align:start position:0% +you actually put a whole system into +water or introduce something really + + align:start position:0% +water or introduce something really + + + align:start position:0% +water or introduce something really +dramatic very big drag force then you + + align:start position:0% +dramatic very big drag force then you + + + align:start position:0% +dramatic very big drag force then you +have over temp situation and you see + + align:start position:0% +have over temp situation and you see + + + align:start position:0% +have over temp situation and you see +that the solution is actually a sum of + + align:start position:0% +that the solution is actually a sum of + + + align:start position:0% +that the solution is actually a sum of +two exponential function so this is + + align:start position:0% +two exponential function so this is + + + align:start position:0% +two exponential function so this is +actually the one equation which actually + + align:start position:0% +actually the one equation which actually + + + align:start position:0% +actually the one equation which actually +works for all the tempte system we + + align:start position:0% +works for all the tempte system we + + + align:start position:0% +works for all the tempte system we +discuss up to now and that is actually + + align:start position:0% +discuss up to now and that is actually + + + align:start position:0% +discuss up to now and that is actually +the map basically if gamma goes to zero + + align:start position:0% +the map basically if gamma goes to zero + + + align:start position:0% +the map basically if gamma goes to zero +gamma Z should control the size of the + + align:start position:0% +gamma Z should control the size of the + + + align:start position:0% +gamma Z should control the size of the +drag force then we got no tamping then + + align:start position:0% +drag force then we got no tamping then + + + align:start position:0% +drag force then we got no tamping then +you have a pure simple harmonic motion + + align:start position:0% +you have a pure simple harmonic motion + + + align:start position:0% +you have a pure simple harmonic motion +and as we increase the gamma then you + + align:start position:0% +and as we increase the gamma then you + + + align:start position:0% +and as we increase the gamma then you +can see that the behavior is changing as + + align:start position:0% +can see that the behavior is changing as + + + align:start position:0% +can see that the behavior is changing as +we increase the gamma so you can see + + align:start position:0% +we increase the gamma so you can see + + + align:start position:0% +we increase the gamma so you can see +that we can use a quat quantity which is + + align:start position:0% +that we can use a quat quantity which is + + + align:start position:0% +that we can use a quat quantity which is +called Q q is actually defined as a + + align:start position:0% +called Q q is actually defined as a + + + align:start position:0% +called Q q is actually defined as a +ratio of Omega zero which is actually + + align:start position:0% +ratio of Omega zero which is actually + + + align:start position:0% +ratio of Omega zero which is actually +the natural frequency angular frequency + + align:start position:0% +the natural frequency angular frequency + + + align:start position:0% +the natural frequency angular frequency +of the system okay + + align:start position:0% +of the system okay + + + align:start position:0% +of the system okay +and gamma is actually a measure of how + + align:start position:0% +and gamma is actually a measure of how + + + align:start position:0% +and gamma is actually a measure of how +big the track force is if we make a + + align:start position:0% +big the track force is if we make a + + + align:start position:0% +big the track force is if we make a +ratio of these two quantity then you + + align:start position:0% +ratio of these two quantity then you + + + align:start position:0% +ratio of these two quantity then you +will see that at Q equal to point five + + align:start position:0% +will see that at Q equal to point five + + + align:start position:0% +will see that at Q equal to point five +it reach a critical point which actually + + align:start position:0% +it reach a critical point which actually + + + align:start position:0% +it reach a critical point which actually +hold the behavior ball whole system + + align:start position:0% +hold the behavior ball whole system + + + align:start position:0% +hold the behavior ball whole system +changed and you can see that the + + align:start position:0% +changed and you can see that the + + + align:start position:0% +changed and you can see that the +oscillation completely disappeared + + align:start position:0% +oscillation completely disappeared + + + align:start position:0% +oscillation completely disappeared +okay so that is actually what we have + + align:start position:0% +okay so that is actually what we have + + + align:start position:0% +okay so that is actually what we have +learned last time so what are we going + + align:start position:0% +learned last time so what are we going + + + align:start position:0% +learned last time so what are we going +to do today we have been really doing + + align:start position:0% +to do today we have been really doing + + + align:start position:0% +to do today we have been really doing +experiment really without our hands and + + align:start position:0% +experiment really without our hands and + + + align:start position:0% +experiment really without our hands and +Sun right so basically we we prepare the + + align:start position:0% +Sun right so basically we we prepare the + + + align:start position:0% +Sun right so basically we we prepare the +system then we release it then we don't + + align:start position:0% +system then we release it then we don't + + + align:start position:0% +system then we release it then we don't +touch it again and see how this system + + align:start position:0% +touch it again and see how this system + + + align:start position:0% +touch it again and see how this system +actually evolve as a function of time + + align:start position:0% +actually evolve as a function of time + + + align:start position:0% +actually evolve as a function of time +all right so that's actually what we + + align:start position:0% +all right so that's actually what we + + + align:start position:0% +all right so that's actually what we +have been doing so today what we are + + align:start position:0% +have been doing so today what we are + + + align:start position:0% +have been doing so today what we are +going to do is to start to drive this + + align:start position:0% +going to do is to start to drive this + + + align:start position:0% +going to do is to start to drive this +system okay we can introduce some some + + align:start position:0% +system okay we can introduce some some + + + align:start position:0% +system okay we can introduce some some +kind of driving force and see what how + + align:start position:0% +kind of driving force and see what how + + + align:start position:0% +kind of driving force and see what how +this system will respond to this + + align:start position:0% +this system will respond to this + + + align:start position:0% +this system will respond to this +external force okay so that is actually + + align:start position:0% +external force okay so that is actually + + + align:start position:0% +external force okay so that is actually +what we are going to do and that now + + align:start position:0% +what we are going to do and that now + + + align:start position:0% +what we are going to do and that now +will bring us to the situation of tempt + + align:start position:0% +will bring us to the situation of tempt + + + align:start position:0% +will bring us to the situation of tempt +driven harmonic oscillator okay so + + align:start position:0% +driven harmonic oscillator okay so + + + align:start position:0% +driven harmonic oscillator okay so +that's immediately get started so we + + align:start position:0% +that's immediately get started so we + + + align:start position:0% +that's immediately get started so we +will use the example which we went + + align:start position:0% +will use the example which we went + + + align:start position:0% +will use the example which we went +through last time as a starting point + + align:start position:0% +through last time as a starting point + + + align:start position:0% +through last time as a starting point +so it's a example from the last lecture + + align:start position:0% +so it's a example from the last lecture + + + align:start position:0% +so it's a example from the last lecture +is a lot which is a fix on the wall and + + align:start position:0% +is a lot which is a fix on the wall and + + + align:start position:0% +is a lot which is a fix on the wall and +the length of this rod is a over two and + + align:start position:0% +the length of this rod is a over two and + + + align:start position:0% +the length of this rod is a over two and +I define a contact hunter clockwise + + align:start position:0% +I define a contact hunter clockwise + + + align:start position:0% +I define a contact hunter clockwise +direction to be positive and I measure + + align:start position:0% +direction to be positive and I measure + + + align:start position:0% +direction to be positive and I measure +the position of the rod by this Seeta + + align:start position:0% +the position of the rod by this Seeta + + + align:start position:0% +the position of the rod by this Seeta +which is the angle between the vertical + + align:start position:0% +which is the angle between the vertical + + + align:start position:0% +which is the angle between the vertical +direction and the pointing direction of + + align:start position:0% +direction and the pointing direction of + + + align:start position:0% +direction and the pointing direction of +the rod okay and we have went through + + align:start position:0% +the rod okay and we have went through + + + align:start position:0% +the rod okay and we have went through +the mass and we got the equation of + + align:start position:0% +the mass and we got the equation of + + + align:start position:0% +the mass and we got the equation of +motion without external force which is + + align:start position:0% +motion without external force which is + + + align:start position:0% +motion without external force which is +already show another blackboard so now + + align:start position:0% +already show another blackboard so now + + + align:start position:0% +already show another blackboard so now +as I mentioned in the beginning I would + + align:start position:0% +as I mentioned in the beginning I would + + + align:start position:0% +as I mentioned in the beginning I would +like to add a driving force or stator + + align:start position:0% +like to add a driving force or stator + + + align:start position:0% +like to add a driving force or stator +driving torque power drive okay this is + + align:start position:0% +driving torque power drive okay this is + + + align:start position:0% +driving torque power drive okay this is +equal to the zero cosine Omega T key + + align:start position:0% +equal to the zero cosine Omega T key + + + align:start position:0% +equal to the zero cosine Omega T key +okay so I'm adding a driving force with + + align:start position:0% +okay so I'm adding a driving force with + + + align:start position:0% +okay so I'm adding a driving force with +driving power + + align:start position:0% +driving power + + + align:start position:0% +driving power +the amplitude with the torque is + + align:start position:0% +the amplitude with the torque is + + + align:start position:0% +the amplitude with the torque is +actually d0 okay and it's actually also + + align:start position:0% +actually d0 okay and it's actually also + + + align:start position:0% +actually d0 okay and it's actually also +a harmonic oscillator force or fork and + + align:start position:0% +a harmonic oscillator force or fork and + + + align:start position:0% +a harmonic oscillator force or fork and +the frequency the angular frequency of + + align:start position:0% +the frequency the angular frequency of + + + align:start position:0% +the frequency the angular frequency of +this torque is only omega D okay and + + align:start position:0% +this torque is only omega D okay and + + + align:start position:0% +this torque is only omega D okay and +that means our total torque tau of T + + align:start position:0% +that means our total torque tau of T + + + align:start position:0% +that means our total torque tau of T +will be equal to tau G T this is + + align:start position:0% +will be equal to tau G T this is + + + align:start position:0% +will be equal to tau G T this is +actually coming from the gravitational + + align:start position:0% +actually coming from the gravitational + + + align:start position:0% +actually coming from the gravitational +force plus tau drag which is a song for + + align:start position:0% +force plus tau drag which is a song for + + + align:start position:0% +force plus tau drag which is a song for +the drag force and and also this time I + + align:start position:0% +the drag force and and also this time I + + + align:start position:0% +the drag force and and also this time I +we are adding in at outdrive okay so I'm + + align:start position:0% +we are adding in at outdrive okay so I'm + + + align:start position:0% +we are adding in at outdrive okay so I'm +not going to go over all the calculation + + align:start position:0% +not going to go over all the calculation + + + align:start position:0% +not going to go over all the calculation +how to derive from the beginning to the + + align:start position:0% +how to derive from the beginning to the + + + align:start position:0% +how to derive from the beginning to the +end but I will just continue from what + + align:start position:0% +end but I will just continue from what + + + align:start position:0% +end but I will just continue from what +we actually start the last time so if I + + align:start position:0% +we actually start the last time so if I + + + align:start position:0% +we actually start the last time so if I +have additional driving torque there + + align:start position:0% +have additional driving torque there + + + align:start position:0% +have additional driving torque there +that means my equation of motion will be + + align:start position:0% +that means my equation of motion will be + + + align:start position:0% +that means my equation of motion will be +slightly modified this time my equation + + align:start position:0% +slightly modified this time my equation + + + align:start position:0% +slightly modified this time my equation +of motion will become theta double dot + + align:start position:0% +of motion will become theta double dot + + + align:start position:0% +of motion will become theta double dot +plus gamma theta dot plus Omega 0 square + + align:start position:0% +plus gamma theta dot plus Omega 0 square + + + align:start position:0% +plus gamma theta dot plus Omega 0 square +theta and that is equal to t0 divided by + + align:start position:0% +theta and that is equal to t0 divided by + + + align:start position:0% +theta and that is equal to t0 divided by +I okay this is actually divided by I + + align:start position:0% +I okay this is actually divided by I + + + align:start position:0% +I okay this is actually divided by I +because in order to get a serration I + + align:start position:0% +because in order to get a serration I + + + align:start position:0% +because in order to get a serration I +need to divide my torque by a moment of + + align:start position:0% +need to divide my torque by a moment of + + + align:start position:0% +need to divide my torque by a moment of +inertia of this system and cosine Omega + + align:start position:0% +inertia of this system and cosine Omega + + + align:start position:0% +inertia of this system and cosine Omega +T this is actually the oscillating + + align:start position:0% +T this is actually the oscillating + + + align:start position:0% +T this is actually the oscillating +frequency of the driving torque okay + + align:start position:0% +frequency of the driving torque okay + + + align:start position:0% +frequency of the driving torque okay +and the just a reminder gamma is equal + + align:start position:0% +and the just a reminder gamma is equal + + + align:start position:0% +and the just a reminder gamma is equal +to find two to be equal to 3b over and L + + align:start position:0% +to find two to be equal to 3b over and L + + + align:start position:0% +to find two to be equal to 3b over and L +square and the Omega zero is actually + + align:start position:0% +square and the Omega zero is actually + + + align:start position:0% +square and the Omega zero is actually +defined to be square root of 3G or but + + align:start position:0% +defined to be square root of 3G or but + + + align:start position:0% +defined to be square root of 3G or but +well okay so as I mentioned in the + + align:start position:0% +well okay so as I mentioned in the + + + align:start position:0% +well okay so as I mentioned in the +beginning this is actually giving you a + + align:start position:0% +beginning this is actually giving you a + + + align:start position:0% +beginning this is actually giving you a +sense of the size of the drag force + + align:start position:0% +sense of the size of the drag force + + + align:start position:0% +sense of the size of the drag force +and the right hand side oh my god did ro + + align:start position:0% +and the right hand side oh my god did ro + + + align:start position:0% +and the right hand side oh my god did ro +is actually the nature and group + + align:start position:0% +is actually the nature and group + + + align:start position:0% +is actually the nature and group +frequency okay so of course we can + + align:start position:0% +frequency okay so of course we can + + + align:start position:0% +frequency okay so of course we can +actually simplify this by replacing this + + align:start position:0% +actually simplify this by replacing this + + + align:start position:0% +actually simplify this by replacing this +turn at this constant by a pink bow so + + align:start position:0% +turn at this constant by a pink bow so + + + align:start position:0% +turn at this constant by a pink bow so +the simple I'm choosing is f0 okay and + + align:start position:0% +the simple I'm choosing is f0 okay and + + + align:start position:0% +the simple I'm choosing is f0 okay and +this is defined would be a t0 divided by + + align:start position:0% +this is defined would be a t0 divided by + + + align:start position:0% +this is defined would be a t0 divided by +I okay + + align:start position:0% +I okay + + + align:start position:0% +I okay +therefore I arrive my final equation of + + align:start position:0% +therefore I arrive my final equation of + + + align:start position:0% +therefore I arrive my final equation of +motion Sita double dot plus gamma theta + + align:start position:0% +motion Sita double dot plus gamma theta + + + align:start position:0% +motion Sita double dot plus gamma theta +dot plus Omega 0 square Sita and that is + + align:start position:0% +dot plus Omega 0 square Sita and that is + + + align:start position:0% +dot plus Omega 0 square Sita and that is +equal to f0 cosine Omega T P okay so I + + align:start position:0% +equal to f0 cosine Omega T P okay so I + + + align:start position:0% +equal to f0 cosine Omega T P okay so I +hope this looks pretty straightforward + + align:start position:0% +hope this looks pretty straightforward + + + align:start position:0% +hope this looks pretty straightforward +to you so this is our equation of motion + + align:start position:0% +to you so this is our equation of motion + + + align:start position:0% +to you so this is our equation of motion +you can see from this slide so we have + + align:start position:0% +you can see from this slide so we have + + + align:start position:0% +you can see from this slide so we have +three turns in addition to the theta + + align:start position:0% +three turns in addition to the theta + + + align:start position:0% +three turns in addition to the theta +double dot the first one is actually + + align:start position:0% +double dot the first one is actually + + + align:start position:0% +double dot the first one is actually +related to drag force or drag torque the + + align:start position:0% +related to drag force or drag torque the + + + align:start position:0% +related to drag force or drag torque the +second one is actually related to + + align:start position:0% +second one is actually related to + + + align:start position:0% +second one is actually related to +so-called spring force right so that is + + align:start position:0% +so-called spring force right so that is + + + align:start position:0% +so-called spring force right so that is +actually related to the spring constant + + align:start position:0% +actually related to the spring constant + + + align:start position:0% +actually related to the spring constant +or you know because of the restoring + + align:start position:0% +or you know because of the restoring + + + align:start position:0% +or you know because of the restoring +force of the occupational force okay the + + align:start position:0% +force of the occupational force okay the + + + align:start position:0% +force of the occupational force okay the +third one is actually what we just + + align:start position:0% +third one is actually what we just + + + align:start position:0% +third one is actually what we just +adding is a driving force okay + + align:start position:0% +adding is a driving force okay + + + align:start position:0% +adding is a driving force okay +so one question which I would like to + + align:start position:0% +so one question which I would like to + + + align:start position:0% +so one question which I would like to +ask you is okay so now I bring one more + + align:start position:0% +ask you is okay so now I bring one more + + + align:start position:0% +ask you is okay so now I bring one more +complication to this system so now I'm + + align:start position:0% +complication to this system so now I'm + + + align:start position:0% +complication to this system so now I'm +out driving this system with a different + + align:start position:0% +out driving this system with a different + + + align:start position:0% +out driving this system with a different +frequency which is omega D the question + + align:start position:0% +frequency which is omega D the question + + + align:start position:0% +frequency which is omega D the question +is what would be the rerouting + + align:start position:0% +is what would be the rerouting + + + align:start position:0% +is what would be the rerouting +oscillation frequency of this driven + + align:start position:0% +oscillation frequency of this driven + + + align:start position:0% +oscillation frequency of this driven +harmonic oscillator what is going to + + align:start position:0% +harmonic oscillator what is going to + + + align:start position:0% +harmonic oscillator what is going to +happen well this system actually follow + + align:start position:0% +happen well this system actually follow + + + align:start position:0% +happen well this system actually follow +the original tempt oscillator frequency + + align:start position:0% +the original tempt oscillator frequency + + + align:start position:0% +the original tempt oscillator frequency +Omega + + align:start position:0% +Omega + + + align:start position:0% +Omega +which is actually close to Omega zero or + + align:start position:0% +which is actually close to Omega zero or + + + align:start position:0% +which is actually close to Omega zero or +where this system as we follow that try + + align:start position:0% +where this system as we follow that try + + + align:start position:0% +where this system as we follow that try +to enforce frequency finally maybe this + + align:start position:0% +to enforce frequency finally maybe this + + + align:start position:0% +to enforce frequency finally maybe this +system choose to do something in between + + align:start position:0% +system choose to do something in between + + + align:start position:0% +system choose to do something in between +we don't know what is going to happen + + align:start position:0% +we don't know what is going to happen + + + align:start position:0% +we don't know what is going to happen +okay so our job today is to solve this + + align:start position:0% +okay so our job today is to solve this + + + align:start position:0% +okay so our job today is to solve this +equation of motion and see what we can + + align:start position:0% +equation of motion and see what we can + + + align:start position:0% +equation of motion and see what we can +learn from the mathematics then actually + + align:start position:0% +learn from the mathematics then actually + + + align:start position:0% +learn from the mathematics then actually +we can actually care for the check or + + align:start position:0% +we can actually care for the check or + + + align:start position:0% +we can actually care for the check or +those results to see if that agrees with + + align:start position:0% +those results to see if that agrees with + + + align:start position:0% +those results to see if that agrees with +the experimental result which through + + align:start position:0% +the experimental result which through + + + align:start position:0% +the experimental result which through +those pay demos okay so as usual I have + + align:start position:0% +those pay demos okay so as usual I have + + + align:start position:0% +those pay demos okay so as usual I have +this equation of motion here so one + + align:start position:0% +this equation of motion here so one + + + align:start position:0% +this equation of motion here so one +trick which I have been using is to come + + align:start position:0% +trick which I have been using is to come + + + align:start position:0% +trick which I have been using is to come +go to complex notation right therefore I + + align:start position:0% +go to complex notation right therefore I + + + align:start position:0% +go to complex notation right therefore I +can now rewrite this thing to be Z + + align:start position:0% +can now rewrite this thing to be Z + + + align:start position:0% +can now rewrite this thing to be Z +double dot plus gamma Z dot plus Omega 0 + + align:start position:0% +double dot plus gamma Z dot plus Omega 0 + + + align:start position:0% +double dot plus gamma Z dot plus Omega 0 +square 3 and that is equal to f0 + + align:start position:0% +square 3 and that is equal to f0 + + + align:start position:0% +square 3 and that is equal to f0 +exponential I Omega T T okay so + + align:start position:0% +exponential I Omega T T okay so + + + align:start position:0% +exponential I Omega T T okay so +basically I just go to the complex + + align:start position:0% +basically I just go to the complex + + + align:start position:0% +basically I just go to the complex +notation and we would like to solve this + + align:start position:0% +notation and we would like to solve this + + + align:start position:0% +notation and we would like to solve this +equation so in order to solve this + + align:start position:0% +equation so in order to solve this + + + align:start position:0% +equation so in order to solve this +equation + + align:start position:0% +equation + + + align:start position:0% +equation +I make cast a test function I guess Z of + + align:start position:0% +I make cast a test function I guess Z of + + + align:start position:0% +I make cast a test function I guess Z of +T have this functional form this is + + align:start position:0% +T have this functional form this is + + + align:start position:0% +T have this functional form this is +equal to a some kind of amplitude ok + + align:start position:0% +equal to a some kind of amplitude ok + + + align:start position:0% +equal to a some kind of amplitude ok +exponential I Omega DT minus Delta Delta + + align:start position:0% +exponential I Omega DT minus Delta Delta + + + align:start position:0% +exponential I Omega DT minus Delta Delta +is actually some kind of angle which is + + align:start position:0% +is actually some kind of angle which is + + + align:start position:0% +is actually some kind of angle which is +actually to account for the possible + + align:start position:0% +actually to account for the possible + + + align:start position:0% +actually to account for the possible +delay of the system okay so so if I + + align:start position:0% +delay of the system okay so so if I + + + align:start position:0% +delay of the system okay so so if I +start to type for example this is a + + align:start position:0% +start to type for example this is a + + + align:start position:0% +start to type for example this is a +system which I'm interested I start to + + align:start position:0% +system which I'm interested I start to + + + align:start position:0% +system which I'm interested I start to +drive this system it may take some time + + align:start position:0% +drive this system it may take some time + + + align:start position:0% +drive this system it may take some time +for the system to react to your driving + + align:start position:0% +for the system to react to your driving + + + align:start position:0% +for the system to react to your driving +force right so that's actually accounted + + align:start position:0% +force right so that's actually accounted + + + align:start position:0% +force right so that's actually accounted +for by this Delta constant okay + + align:start position:0% +for by this Delta constant okay + + + align:start position:0% +for by this Delta constant okay +and the amplitude is actually what we + + align:start position:0% +and the amplitude is actually what we + + + align:start position:0% +and the amplitude is actually what we +were wondering what will be the + + align:start position:0% +were wondering what will be the + + + align:start position:0% +were wondering what will be the +amplitude therefore you have some kind + + align:start position:0% +amplitude therefore you have some kind + + + align:start position:0% +amplitude therefore you have some kind +of constant in front of the exponential + + align:start position:0% +of constant in front of the exponential + + + align:start position:0% +of constant in front of the exponential +function and you can see that this + + align:start position:0% +function and you can see that this + + + align:start position:0% +function and you can see that this +exponential is actually having angular + + align:start position:0% +exponential is actually having angular + + + align:start position:0% +exponential is actually having angular +frequency Omega T and that is actually + + align:start position:0% +frequency Omega T and that is actually + + + align:start position:0% +frequency Omega T and that is actually +designed to actually to cancel this + + align:start position:0% +designed to actually to cancel this + + + align:start position:0% +designed to actually to cancel this +exponential I Omega DT here in new track + + align:start position:0% +exponential I Omega DT here in new track + + + align:start position:0% +exponential I Omega DT here in new track +force okay so now we can actually + + align:start position:0% +force okay so now we can actually + + + align:start position:0% +force okay so now we can actually +calculate what the dot of T will be + + align:start position:0% +calculate what the dot of T will be + + + align:start position:0% +calculate what the dot of T will be +equal to I Omega D Z Z double dot T will + + align:start position:0% +equal to I Omega D Z Z double dot T will + + + align:start position:0% +equal to I Omega D Z Z double dot T will +be equal to minus Omega T squared C okay + + align:start position:0% +be equal to minus Omega T squared C okay + + + align:start position:0% +be equal to minus Omega T squared C okay +it's DOS we can now plug the back into + + align:start position:0% +it's DOS we can now plug the back into + + + align:start position:0% +it's DOS we can now plug the back into +this equation of motion and I see what + + align:start position:0% +this equation of motion and I see what + + + align:start position:0% +this equation of motion and I see what +we can as you learn from there okay so + + align:start position:0% +we can as you learn from there okay so + + + align:start position:0% +we can as you learn from there okay so +basically what I'm going to is to insert + + align:start position:0% +basically what I'm going to is to insert + + + align:start position:0% +basically what I'm going to is to insert +all those things back into the equation + + align:start position:0% +all those things back into the equation + + + align:start position:0% +all those things back into the equation +of motion and that is actually going to + + align:start position:0% +of motion and that is actually going to + + + align:start position:0% +of motion and that is actually going to +be like this basically the first time + + align:start position:0% +be like this basically the first time + + + align:start position:0% +be like this basically the first time +the double dot you get a minus Omega T + + align:start position:0% +the double dot you get a minus Omega T + + + align:start position:0% +the double dot you get a minus Omega T +Square out of it the second term gamma Z + + align:start position:0% +Square out of it the second term gamma Z + + + align:start position:0% +Square out of it the second term gamma Z +dot I have the g'tok here basically I + + align:start position:0% +dot I have the g'tok here basically I + + + align:start position:0% +dot I have the g'tok here basically I +will get plus I Omega D gamma out of + + align:start position:0% +will get plus I Omega D gamma out of + + + align:start position:0% +will get plus I Omega D gamma out of +this the second turn the certain I get + + align:start position:0% +this the second turn the certain I get + + + align:start position:0% +this the second turn the certain I get +omega 0 square out of it and that is + + align:start position:0% +omega 0 square out of it and that is + + + align:start position:0% +omega 0 square out of it and that is +actually multiplied by Z and this is + + align:start position:0% +actually multiplied by Z and this is + + + align:start position:0% +actually multiplied by Z and this is +equal to f0 exponential I Omega DT okay + + align:start position:0% + + + + align:start position:0% + +all right and we also know from this + + align:start position:0% +all right and we also know from this + + + align:start position:0% +all right and we also know from this +expression okay Z is equal to a + + align:start position:0% +expression okay Z is equal to a + + + align:start position:0% +expression okay Z is equal to a +exponential I Omega DT minus Delta + + align:start position:0% +exponential I Omega DT minus Delta + + + align:start position:0% +exponential I Omega DT minus Delta +that's the tester function so this is + + align:start position:0% +that's the tester function so this is + + + align:start position:0% +that's the tester function so this is +actually equal to a exponential I Omega + + align:start position:0% +actually equal to a exponential I Omega + + + align:start position:0% +actually equal to a exponential I Omega +DT minus Delta okay so now what I can do + + align:start position:0% +DT minus Delta okay so now what I can do + + + align:start position:0% +DT minus Delta okay so now what I can do +you say huh I have some kind of some + + align:start position:0% +you say huh I have some kind of some + + + align:start position:0% +you say huh I have some kind of some +constant in the front multiplied by + + align:start position:0% +constant in the front multiplied by + + + align:start position:0% +constant in the front multiplied by +exponential I Omega DT and now I can + + align:start position:0% +exponential I Omega DT and now I can + + + align:start position:0% +exponential I Omega DT and now I can +actually cancel this exponential I Omega + + align:start position:0% +actually cancel this exponential I Omega + + + align:start position:0% +actually cancel this exponential I Omega +DT with the right hand side turn very + + align:start position:0% +DT with the right hand side turn very + + + align:start position:0% +DT with the right hand side turn very +good the whole system is actually the + + align:start position:0% +good the whole system is actually the + + + align:start position:0% +good the whole system is actually the +whole equation is actually exponential + + align:start position:0% +whole equation is actually exponential + + + align:start position:0% +whole equation is actually exponential +free right okay now I don't have any + + align:start position:0% +free right okay now I don't have any + + + align:start position:0% +free right okay now I don't have any +exponential function left and + + align:start position:0% +exponential function left and + + + align:start position:0% +exponential function left and +exponential I Delta si should be just a + + align:start position:0% +exponential I Delta si should be just a + + + align:start position:0% +exponential I Delta si should be just a +constant so it's actually now this + + align:start position:0% +constant so it's actually now this + + + align:start position:0% +constant so it's actually now this +equation is actually independent of time + + align:start position:0% +equation is actually independent of time + + + align:start position:0% +equation is actually independent of time +okay so what I'm getting is like this + + align:start position:0% +okay so what I'm getting is like this + + + align:start position:0% +okay so what I'm getting is like this +specially if I multiply both side by + + align:start position:0% +specially if I multiply both side by + + + align:start position:0% +specially if I multiply both side by +exponential I Delta then I get minus + + align:start position:0% +exponential I Delta then I get minus + + + align:start position:0% +exponential I Delta then I get minus +Omega T squared plus I Omega DT plus + + align:start position:0% +Omega T squared plus I Omega DT plus + + + align:start position:0% +Omega T squared plus I Omega DT plus +Omega 0 square a and this is going to be + + align:start position:0% +Omega 0 square a and this is going to be + + + align:start position:0% +Omega 0 square a and this is going to be +equal to F exponential I Delta because I + + align:start position:0% +equal to F exponential I Delta because I + + + align:start position:0% +equal to F exponential I Delta because I +multiply both side by exponential I + + align:start position:0% +multiply both side by exponential I + + + align:start position:0% +multiply both side by exponential I +Delta okay and this is equal to F cosine + + align:start position:0% +Delta okay and this is equal to F cosine + + + align:start position:0% +Delta okay and this is equal to F cosine +theta plus I sine Delta just use the + + align:start position:0% +theta plus I sine Delta just use the + + + align:start position:0% +theta plus I sine Delta just use the +Euler's equation okay any questions so + + align:start position:0% +Euler's equation okay any questions so + + + align:start position:0% +Euler's equation okay any questions so +far + + align:start position:0% + + + + align:start position:0% + +okay so look at what I have been doing + + align:start position:0% +okay so look at what I have been doing + + + align:start position:0% +okay so look at what I have been doing +so I have this equation of motion a + + align:start position:0% +so I have this equation of motion a + + + align:start position:0% +so I have this equation of motion a +studio I go to complex notation then I + + align:start position:0% +studio I go to complex notation then I + + + align:start position:0% +studio I go to complex notation then I +guess Z equal to a exponential I Omega + + align:start position:0% +guess Z equal to a exponential I Omega + + + align:start position:0% +guess Z equal to a exponential I Omega +DT minus Delta because my friends from + + align:start position:0% +DT minus Delta because my friends from + + + align:start position:0% +DT minus Delta because my friends from +the math department already stopped this + + align:start position:0% +the math department already stopped this + + + align:start position:0% +the math department already stopped this +and I'm just following it okay then I + + align:start position:0% +and I'm just following it okay then I + + + align:start position:0% +and I'm just following it okay then I +can calculate all those turns plug them + + align:start position:0% +can calculate all those turns plug them + + + align:start position:0% +can calculate all those turns plug them +in and the end the basically you will + + align:start position:0% +in and the end the basically you will + + + align:start position:0% +in and the end the basically you will +arrive this equation okay + + align:start position:0% +arrive this equation okay + + + align:start position:0% +arrive this equation okay +this equation is a complex equation + + align:start position:0% +this equation is a complex equation + + + align:start position:0% +this equation is a complex equation +right so what does that mean + + align:start position:0% +right so what does that mean + + + align:start position:0% +right so what does that mean +that means one equation is equal to two + + align:start position:0% +that means one equation is equal to two + + + align:start position:0% +that means one equation is equal to two +equation right because you have the real + + align:start position:0% +equation right because you have the real + + + align:start position:0% +equation right because you have the real +part you have the imagery part okay + + align:start position:0% +part you have the imagery part okay + + + align:start position:0% +part you have the imagery part okay +therefore that's very nice because I + + align:start position:0% +therefore that's very nice because I + + + align:start position:0% +therefore that's very nice because I +have two unknown the first one is a + + align:start position:0% +have two unknown the first one is a + + + align:start position:0% +have two unknown the first one is a +constant and the second one is Delta now + + align:start position:0% +constant and the second one is Delta now + + + align:start position:0% +constant and the second one is Delta now +I have two equations I can solve what + + align:start position:0% +I have two equations I can solve what + + + align:start position:0% +I have two equations I can solve what +would be the functional form for a and + + align:start position:0% +would be the functional form for a and + + + align:start position:0% +would be the functional form for a and +the tota and let me go immediately solve + + align:start position:0% +the tota and let me go immediately solve + + + align:start position:0% +the tota and let me go immediately solve +this equation so if I take the real part + + align:start position:0% +this equation so if I take the real part + + + align:start position:0% +this equation so if I take the real part +a real part front from this equation + + align:start position:0% +a real part front from this equation + + + align:start position:0% +a real part front from this equation +basically what I'm going to get is Omega + + align:start position:0% +basically what I'm going to get is Omega + + + align:start position:0% +basically what I'm going to get is Omega +0 Square this is the this video minus + + align:start position:0% +0 Square this is the this video minus + + + align:start position:0% +0 Square this is the this video minus +Omega T squared okay this is real + + align:start position:0% +Omega T squared okay this is real + + + align:start position:0% +Omega T squared okay this is real +times a is HD sound real number okay + + align:start position:0% +times a is HD sound real number okay + + + align:start position:0% +times a is HD sound real number okay +this is a should equal to F cosine f0 so + + align:start position:0% +this is a should equal to F cosine f0 so + + + align:start position:0% +this is a should equal to F cosine f0 so +I missed a 0 here okay so there are 0 I + + align:start position:0% +I missed a 0 here okay so there are 0 I + + + align:start position:0% +I missed a 0 here okay so there are 0 I +missed okay + + align:start position:0% +missed okay + + + align:start position:0% +missed okay +he should be F 0 ok f0 cosine Delta ok + + align:start position:0% +he should be F 0 ok f0 cosine Delta ok + + + align:start position:0% +he should be F 0 ok f0 cosine Delta ok +and I can also call that all the turns + + align:start position:0% +and I can also call that all the turns + + + align:start position:0% +and I can also call that all the turns +which is imaginary turns then I get only + + align:start position:0% +which is imaginary turns then I get only + + + align:start position:0% +which is imaginary turns then I get only +the second turn from the left hand side + + align:start position:0% +the second turn from the left hand side + + + align:start position:0% +the second turn from the left hand side +is with the I in front of it right + + align:start position:0% +is with the I in front of it right + + + align:start position:0% +is with the I in front of it right +therefore I get Omega T gamma a ok + + align:start position:0% +therefore I get Omega T gamma a ok + + + align:start position:0% +therefore I get Omega T gamma a ok +follow + + align:start position:0% +follow + + + align:start position:0% +follow +up and lap inside and the from the + + align:start position:0% +up and lap inside and the from the + + + align:start position:0% +up and lap inside and the from the +right-hand side is only one imaginary + + align:start position:0% +right-hand side is only one imaginary + + + align:start position:0% +right-hand side is only one imaginary +turn therefore I get this is equal to f0 + + align:start position:0% +turn therefore I get this is equal to f0 + + + align:start position:0% +turn therefore I get this is equal to f0 +sine Delta okay so now I have two + + align:start position:0% +sine Delta okay so now I have two + + + align:start position:0% +sine Delta okay so now I have two +equations I have two unknowns therefore + + align:start position:0% +equations I have two unknowns therefore + + + align:start position:0% +equations I have two unknowns therefore +I can easily solve a and the Delta okay + + align:start position:0% +I can easily solve a and the Delta okay + + + align:start position:0% +I can easily solve a and the Delta okay +so I call this equation number one I + + align:start position:0% +so I call this equation number one I + + + align:start position:0% +so I call this equation number one I +call this equation number two so now I + + align:start position:0% +call this equation number two so now I + + + align:start position:0% +call this equation number two so now I +can sound them in quadrature the two + + align:start position:0% +can sound them in quadrature the two + + + align:start position:0% +can sound them in quadrature the two +equation in portraiture a Latins I will + + align:start position:0% +equation in portraiture a Latins I will + + + align:start position:0% +equation in portraiture a Latins I will +give you a square Omega 0 square minus + + align:start position:0% +give you a square Omega 0 square minus + + + align:start position:0% +give you a square Omega 0 square minus +Omega T squared squared plus Omega t + + align:start position:0% +Omega T squared squared plus Omega t + + + align:start position:0% +Omega T squared squared plus Omega t +square gamma square that essentially + + align:start position:0% +square gamma square that essentially + + + align:start position:0% +square gamma square that essentially +coming from on the second equation okay + + align:start position:0% +coming from on the second equation okay + + + align:start position:0% +coming from on the second equation okay +now give you the lapin side is just a + + align:start position:0% +now give you the lapin side is just a + + + align:start position:0% +now give you the lapin side is just a +square root a square Sun a square the + + align:start position:0% +square root a square Sun a square the + + + align:start position:0% +square root a square Sun a square the +sound of the first day and second + + align:start position:0% +sound of the first day and second + + + align:start position:0% +sound of the first day and second +equation ok and the right hand side will + + align:start position:0% +equation ok and the right hand side will + + + align:start position:0% +equation ok and the right hand side will +become F 0 square cosine Delta cosine + + align:start position:0% +become F 0 square cosine Delta cosine + + + align:start position:0% +become F 0 square cosine Delta cosine +squared theta plus sine squared Delta + + align:start position:0% +squared theta plus sine squared Delta + + + align:start position:0% +squared theta plus sine squared Delta +okay and this is actually equal to 1 + + align:start position:0% +okay and this is actually equal to 1 + + + align:start position:0% +okay and this is actually equal to 1 +alright so that's actually the trick to + + align:start position:0% +alright so that's actually the trick to + + + align:start position:0% +alright so that's actually the trick to +get rid of Delta okay + + align:start position:0% +get rid of Delta okay + + + align:start position:0% +get rid of Delta okay +then I can get what will be the + + align:start position:0% +then I can get what will be the + + + align:start position:0% +then I can get what will be the +resulting a a should be a function of + + align:start position:0% +resulting a a should be a function of + + + align:start position:0% +resulting a a should be a function of +Omega T ok Omega T is given okay to you + + align:start position:0% +Omega T ok Omega T is given okay to you + + + align:start position:0% +Omega T ok Omega T is given okay to you +it's actually determined by you right + + align:start position:0% +it's actually determined by you right + + + align:start position:0% +it's actually determined by you right +how how free as you want to oscillate + + align:start position:0% +how how free as you want to oscillate + + + align:start position:0% +how how free as you want to oscillate +this system ok and this is equal to f0 + + align:start position:0% +this system ok and this is equal to f0 + + + align:start position:0% +this system ok and this is equal to f0 +divided by square root of this whole + + align:start position:0% +divided by square root of this whole + + + align:start position:0% +divided by square root of this whole +thing right so this will give you Omega + + align:start position:0% +thing right so this will give you Omega + + + align:start position:0% +thing right so this will give you Omega +0 square minus Omega T Square + + align:start position:0% +0 square minus Omega T Square + + + align:start position:0% +0 square minus Omega T Square +squared plus Omega P square gamma square + + align:start position:0% + + + + align:start position:0% + +okay then we can also calculate what + + align:start position:0% +okay then we can also calculate what + + + align:start position:0% +okay then we can also calculate what +will be the Delta the trick is to take a + + align:start position:0% +will be the Delta the trick is to take a + + + align:start position:0% +will be the Delta the trick is to take a +ratio between equation number two and + + align:start position:0% +ratio between equation number two and + + + align:start position:0% +ratio between equation number two and +the equation number one 2/1 basically + + align:start position:0% +the equation number one 2/1 basically + + + align:start position:0% +the equation number one 2/1 basically +you will get tangent + + align:start position:0% +you will get tangent + + + align:start position:0% +you will get tangent +dorota right this is scientific if I + + align:start position:0% +dorota right this is scientific if I + + + align:start position:0% +dorota right this is scientific if I +cosign right f zero actually cancel + + align:start position:0% +cosign right f zero actually cancel + + + align:start position:0% +cosign right f zero actually cancel +right and this is equal to what equal to + + align:start position:0% +right and this is equal to what equal to + + + align:start position:0% +right and this is equal to what equal to +the ratio of these two strands right + + align:start position:0% +the ratio of these two strands right + + + align:start position:0% +the ratio of these two strands right +after you take the ratio eight job oh + + align:start position:0% +after you take the ratio eight job oh + + + align:start position:0% +after you take the ratio eight job oh +right basically what you get is gamma + + align:start position:0% +right basically what you get is gamma + + + align:start position:0% +right basically what you get is gamma +Omega T divided by Omega zero squared + + align:start position:0% +Omega T divided by Omega zero squared + + + align:start position:0% +Omega T divided by Omega zero squared +minus Omega T squared okay so we have + + align:start position:0% +minus Omega T squared okay so we have + + + align:start position:0% +minus Omega T squared okay so we have +solved a and Delta through this exercise + + align:start position:0% +solved a and Delta through this exercise + + + align:start position:0% +solved a and Delta through this exercise +okay so what does that mean originally I + + align:start position:0% +okay so what does that mean originally I + + + align:start position:0% +okay so what does that mean originally I +assumed my solution to be a exponential + + align:start position:0% +assumed my solution to be a exponential + + + align:start position:0% +assumed my solution to be a exponential +I Omega DT minus Delta right therefore I + + align:start position:0% +I Omega DT minus Delta right therefore I + + + align:start position:0% +I Omega DT minus Delta right therefore I +would like to go back to the the real + + align:start position:0% +would like to go back to the the real + + + align:start position:0% +would like to go back to the the real +world which is a theta right so + + align:start position:0% +world which is a theta right so + + + align:start position:0% +world which is a theta right so +basically if I take the real part I will + + align:start position:0% +basically if I take the real part I will + + + align:start position:0% +basically if I take the real part I will +get theta of T which is actually the + + align:start position:0% +get theta of T which is actually the + + + align:start position:0% +get theta of T which is actually the +real part of Z okay and that will give + + align:start position:0% +real part of Z okay and that will give + + + align:start position:0% +real part of Z okay and that will give +you a Omega T cosine Omega T t minus + + align:start position:0% +you a Omega T cosine Omega T t minus + + + align:start position:0% +you a Omega T cosine Omega T t minus +theta is also a function of Omega T okay + + align:start position:0% +theta is also a function of Omega T okay + + + align:start position:0% +theta is also a function of Omega T okay +so we have done this exercise and you + + align:start position:0% +so we have done this exercise and you + + + align:start position:0% +so we have done this exercise and you +can see that the first thing which we + + align:start position:0% +can see that the first thing which we + + + align:start position:0% +can see that the first thing which we +see here is that there's no free + + align:start position:0% +see here is that there's no free + + + align:start position:0% +see here is that there's no free +parameter from this solution + + align:start position:0% +parameter from this solution + + + align:start position:0% +parameter from this solution +right a is decided by Omega T and Delta + + align:start position:0% +right a is decided by Omega T and Delta + + + align:start position:0% +right a is decided by Omega T and Delta +is also decided by Omega T there's a lot + + align:start position:0% +is also decided by Omega T there's a lot + + + align:start position:0% +is also decided by Omega T there's a lot +of mass but actually we have over condos + + align:start position:0% +of mass but actually we have over condos + + + align:start position:0% +of mass but actually we have over condos +and we have the solution + + align:start position:0% +and we have the solution + + + align:start position:0% +and we have the solution +but the ad says you clear to you that + + align:start position:0% +but the ad says you clear to you that + + + align:start position:0% +but the ad says you clear to you that +this cannot be the full story right + + align:start position:0% +this cannot be the full story right + + + align:start position:0% +this cannot be the full story right +because you have a second order + + align:start position:0% +because you have a second order + + + align:start position:0% +because you have a second order +differential equation you need to have + + align:start position:0% +differential equation you need to have + + + align:start position:0% +differential equation you need to have +two free parameters in the solution okay + + align:start position:0% +two free parameters in the solution okay + + + align:start position:0% +two free parameters in the solution okay +what is actually missing anybody can + + align:start position:0% +what is actually missing anybody can + + + align:start position:0% +what is actually missing anybody can +tell me what is missing is very good the + + align:start position:0% +tell me what is missing is very good the + + + align:start position:0% +tell me what is missing is very good the +homogeneous solution is missing okay so + + align:start position:0% +homogeneous solution is missing okay so + + + align:start position:0% +homogeneous solution is missing okay so +that's issue why we actually have no pre + + align:start position:0% +that's issue why we actually have no pre + + + align:start position:0% +that's issue why we actually have no pre +parameter here once the Omega T is + + align:start position:0% +parameter here once the Omega T is + + + align:start position:0% +parameter here once the Omega T is +determined once the f0 is given then you + + align:start position:0% +determined once the f0 is given then you + + + align:start position:0% +determined once the f0 is given then you +have the functional form which decide + + align:start position:0% +have the functional form which decide + + + align:start position:0% +have the functional form which decide +what is actually C okay so what + + align:start position:0% +what is actually C okay so what + + + align:start position:0% +what is actually C okay so what +essentially the for solution for full + + align:start position:0% +essentially the for solution for full + + + align:start position:0% +essentially the for solution for full +solution should be as you said a + + align:start position:0% +solution should be as you said a + + + align:start position:0% +solution should be as you said a +combination of homogeneous solution and + + align:start position:0% +combination of homogeneous solution and + + + align:start position:0% +combination of homogeneous solution and +the particular solution which we as we + + align:start position:0% +the particular solution which we as we + + + align:start position:0% +the particular solution which we as we +got here so if I prepare the system to + + align:start position:0% +got here so if I prepare the system to + + + align:start position:0% +got here so if I prepare the system to +be in a situation of for example under + + align:start position:0% +be in a situation of for example under + + + align:start position:0% +be in a situation of for example under +damped situation okay then what I'm + + align:start position:0% +damped situation okay then what I'm + + + align:start position:0% +damped situation okay then what I'm +going to do is actually pretty simple + + align:start position:0% +going to do is actually pretty simple + + + align:start position:0% +going to do is actually pretty simple +what I am going to do is to just to copy + + align:start position:0% +what I am going to do is to just to copy + + + align:start position:0% +what I am going to do is to just to copy +the under damped as a solution from last + + align:start position:0% +the under damped as a solution from last + + + align:start position:0% +the under damped as a solution from last +lecture and combine that with my + + align:start position:0% +lecture and combine that with my + + + align:start position:0% +lecture and combine that with my +particular solution which are obtained + + align:start position:0% +particular solution which are obtained + + + align:start position:0% +particular solution which are obtained +here okay so that's actually see what is + + align:start position:0% +here okay so that's actually see what is + + + align:start position:0% +here okay so that's actually see what is +issue the full solution looks like so I + + align:start position:0% +issue the full solution looks like so I + + + align:start position:0% +issue the full solution looks like so I +have a Omega D cosine Omega DT minus + + align:start position:0% +have a Omega D cosine Omega DT minus + + + align:start position:0% +have a Omega D cosine Omega DT minus +delta is omega T it's a function of + + align:start position:0% +delta is omega T it's a function of + + + align:start position:0% +delta is omega T it's a function of +Omega T okay this is actually does + + align:start position:0% +Omega T okay this is actually does + + + align:start position:0% +Omega T okay this is actually does +so-called a steady stay + + align:start position:0% + + + + align:start position:0% + +solution okay and of course as you + + align:start position:0% +solution okay and of course as you + + + align:start position:0% +solution okay and of course as you +mentioned I need to also add the + + align:start position:0% +mentioned I need to also add the + + + align:start position:0% +mentioned I need to also add the +homogeneous solution and basically that + + align:start position:0% +homogeneous solution and basically that + + + align:start position:0% +homogeneous solution and basically that +decision according to what I wrote there + + align:start position:0% +decision according to what I wrote there + + + align:start position:0% +decision according to what I wrote there +have a functional form of exponential a + + align:start position:0% +have a functional form of exponential a + + + align:start position:0% +have a functional form of exponential a +exponential minus gamma over 2t cosine + + align:start position:0% +exponential minus gamma over 2t cosine + + + align:start position:0% +exponential minus gamma over 2t cosine +Omega T plus alpha so I change a to be + + align:start position:0% +Omega T plus alpha so I change a to be + + + align:start position:0% +Omega T plus alpha so I change a to be +because I already have the a there just + + align:start position:0% +because I already have the a there just + + + align:start position:0% +because I already have the a there just +to avoid confusion okay the basis you + + align:start position:0% +to avoid confusion okay the basis you + + + align:start position:0% +to avoid confusion okay the basis you +get P exponential minus gamma over 2t + + align:start position:0% +get P exponential minus gamma over 2t + + + align:start position:0% +get P exponential minus gamma over 2t +cosine Omega T plus alpha + + align:start position:0% +cosine Omega T plus alpha + + + align:start position:0% +cosine Omega T plus alpha +okay crazy D there are two three + + align:start position:0% +okay crazy D there are two three + + + align:start position:0% +okay crazy D there are two three +parameters a B and alpha those two three + + align:start position:0% +parameters a B and alpha those two three + + + align:start position:0% +parameters a B and alpha those two three +parameters can be determined by initial + + align:start position:0% +parameters can be determined by initial + + + align:start position:0% +parameters can be determined by initial +conditions okay so for example initially + + align:start position:0% +conditions okay so for example initially + + + align:start position:0% +conditions okay so for example initially +I I actually release the rod and some + + align:start position:0% +I I actually release the rod and some + + + align:start position:0% +I I actually release the rod and some +fixed angle of Sita initial and also the + + align:start position:0% +fixed angle of Sita initial and also the + + + align:start position:0% +fixed angle of Sita initial and also the +initial velocity is zero then I can + + align:start position:0% +initial velocity is zero then I can + + + align:start position:0% +initial velocity is zero then I can +actually practice solution in using + + align:start position:0% +actually practice solution in using + + + align:start position:0% +actually practice solution in using +those initial conditions to solve P and + + align:start position:0% +those initial conditions to solve P and + + + align:start position:0% +those initial conditions to solve P and +alpha okay any questions so far + + align:start position:0% +alpha okay any questions so far + + + align:start position:0% +alpha okay any questions so far +yes yeah iein assuming it's under damp + + align:start position:0% +yes yeah iein assuming it's under damp + + + align:start position:0% +yes yeah iein assuming it's under damp +to situation okay so that's an + + align:start position:0% +to situation okay so that's an + + + align:start position:0% +to situation okay so that's an +assumption so if if the it depends on + + align:start position:0% +assumption so if if the it depends on + + + align:start position:0% +assumption so if if the it depends on +the size of gamma and Omega zero right + + align:start position:0% +the size of gamma and Omega zero right + + + align:start position:0% +the size of gamma and Omega zero right +then you actually have actually four + + align:start position:0% +then you actually have actually four + + + align:start position:0% +then you actually have actually four +different kinds of solution right if + + align:start position:0% +different kinds of solution right if + + + align:start position:0% +different kinds of solution right if +gamma is equal to zero then what you are + + align:start position:0% +gamma is equal to zero then what you are + + + align:start position:0% +gamma is equal to zero then what you are +going to plug in is the solution from no + + align:start position:0% +going to plug in is the solution from no + + + align:start position:0% +going to plug in is the solution from no +damping as you were homogeneous solution + + align:start position:0% +damping as you were homogeneous solution + + + align:start position:0% +damping as you were homogeneous solution +okay and then you if you prepare this + + align:start position:0% +okay and then you if you prepare this + + + align:start position:0% +okay and then you if you prepare this +system under water + + align:start position:0% +system under water + + + align:start position:0% +system under water +you know damping's color so it is huge + + align:start position:0% +you know damping's color so it is huge + + + align:start position:0% +you know damping's color so it is huge +then you actually plug in the over + + align:start position:0% +then you actually plug in the over + + + align:start position:0% +then you actually plug in the over +damped solution to be your homogeneous + + align:start position:0% +damped solution to be your homogeneous + + + align:start position:0% +damped solution to be your homogeneous +part of the solution + + align:start position:0% +part of the solution + + + align:start position:0% +part of the solution +okay any other questions very good + + align:start position:0% +okay any other questions very good + + + align:start position:0% +okay any other questions very good +question + + align:start position:0% +question + + + align:start position:0% +question +okay so now maybe you got confused a bit + + align:start position:0% +okay so now maybe you got confused a bit + + + align:start position:0% +okay so now maybe you got confused a bit +right I have now Omega T I have also + + align:start position:0% +right I have now Omega T I have also + + + align:start position:0% +right I have now Omega T I have also +Omega and these are another one we just + + align:start position:0% +Omega and these are another one we just + + + align:start position:0% +Omega and these are another one we just +called Omega zero what are they what are + + align:start position:0% +called Omega zero what are they what are + + + align:start position:0% +called Omega zero what are they what are +those right + + align:start position:0% +those right + + + align:start position:0% +those right +so Omega zero is the nature angular + + align:start position:0% +so Omega zero is the nature angular + + + align:start position:0% +so Omega zero is the nature angular +frequency without even the track force + + align:start position:0% +frequency without even the track force + + + align:start position:0% +frequency without even the track force +okay if you remove everything just like + + align:start position:0% +okay if you remove everything just like + + + align:start position:0% +okay if you remove everything just like +you know without considering any drag + + align:start position:0% +you know without considering any drag + + + align:start position:0% +you know without considering any drag +force as a child and naturally the + + align:start position:0% +force as a child and naturally the + + + align:start position:0% +force as a child and naturally the +natural frequency of the system and what + + align:start position:0% +natural frequency of the system and what + + + align:start position:0% +natural frequency of the system and what +is Omega Omega according to that + + align:start position:0% +is Omega Omega according to that + + + align:start position:0% +is Omega Omega according to that +function okay Omega is defined to be + + align:start position:0% +function okay Omega is defined to be + + + align:start position:0% +function okay Omega is defined to be +Omega square minus gamma square over + + align:start position:0% +Omega square minus gamma square over + + + align:start position:0% +Omega square minus gamma square over +fourth square do though that that + + align:start position:0% +fourth square do though that that + + + align:start position:0% +fourth square do though that that +essentially the oscillation frequency + + align:start position:0% +essentially the oscillation frequency + + + align:start position:0% +essentially the oscillation frequency +which way I should discuss last lecture + + align:start position:0% +which way I should discuss last lecture + + + align:start position:0% +which way I should discuss last lecture +after you add drag force into the gap + + align:start position:0% +after you add drag force into the gap + + + align:start position:0% +after you add drag force into the gap +okay finally Omega T is how fast you + + align:start position:0% +okay finally Omega T is how fast you + + + align:start position:0% +okay finally Omega T is how fast you +actually type this system okay so that + + align:start position:0% +actually type this system okay so that + + + align:start position:0% +actually type this system okay so that +is actually the definition of these + + align:start position:0% +is actually the definition of these + + + align:start position:0% +is actually the definition of these +three omegas okay so you can see that if + + align:start position:0% +three omegas okay so you can see that if + + + align:start position:0% +three omegas okay so you can see that if +I prepare my solution to be in under + + align:start position:0% +I prepare my solution to be in under + + + align:start position:0% +I prepare my solution to be in under +template situation then basically you + + align:start position:0% +template situation then basically you + + + align:start position:0% +template situation then basically you +see that this is actually so-called + + align:start position:0% +see that this is actually so-called + + + align:start position:0% +see that this is actually so-called +steady state solution because the a + + align:start position:0% +steady state solution because the a + + + align:start position:0% +steady state solution because the a +Omega D is a constant so it's going to + + align:start position:0% +Omega D is a constant so it's going to + + + align:start position:0% +Omega D is a constant so it's going to +be there forever right and the second + + align:start position:0% +be there forever right and the second + + + align:start position:0% +be there forever right and the second +second time is actually P exponential + + align:start position:0% +second time is actually P exponential + + + align:start position:0% +second time is actually P exponential +minus gamma over 2t it's decaying as a + + align:start position:0% +minus gamma over 2t it's decaying as a + + + align:start position:0% +minus gamma over 2t it's decaying as a +function of time so if you are patient + + align:start position:0% +function of time so if you are patient + + + align:start position:0% +function of time so if you are patient +enough you wait then this will be gone + + align:start position:0% +enough you wait then this will be gone + + + align:start position:0% +enough you wait then this will be gone +right okay so that is actually how we + + align:start position:0% +right okay so that is actually how we + + + align:start position:0% +right okay so that is actually how we +actually understand this mathematical + + align:start position:0% +actually understand this mathematical + + + align:start position:0% +actually understand this mathematical +result and then of course you can + + align:start position:0% +result and then of course you can + + + align:start position:0% +result and then of course you can +actually take a look at this this is + + align:start position:0% +actually take a look at this this is + + + align:start position:0% +actually take a look at this this is +actually just assuming some kind of + + align:start position:0% +actually just assuming some kind of + + + align:start position:0% +actually just assuming some kind of +initial condition and Prague in the + + align:start position:0% +initial condition and Prague in the + + + align:start position:0% +initial condition and Prague in the +solution and profit as a function of + + align:start position:0% +solution and profit as a function of + + + align:start position:0% +solution and profit as a function of +time + + align:start position:0% +time + + + align:start position:0% +time +okay and you can see that this function + + align:start position:0% +okay and you can see that this function + + + align:start position:0% +okay and you can see that this function +looks really weird look a bit surprising + + align:start position:0% +looks really weird look a bit surprising + + + align:start position:0% +looks really weird look a bit surprising +what does that mean right looks really + + align:start position:0% +what does that mean right looks really + + + align:start position:0% +what does that mean right looks really +strange but at some point this + + align:start position:0% +strange but at some point this + + + align:start position:0% +strange but at some point this +superposition of this to function + + align:start position:0% +superposition of this to function + + + align:start position:0% +superposition of this to function +because one of the function H Street + + align:start position:0% +because one of the function H Street + + + align:start position:0% +because one of the function H Street +dies out disappear + + align:start position:0% +dies out disappear + + + align:start position:0% +dies out disappear +then you will see that huh if you wait + + align:start position:0% +then you will see that huh if you wait + + + align:start position:0% +then you will see that huh if you wait +long enough then you actually only see a + + align:start position:0% +long enough then you actually only see a + + + align:start position:0% +long enough then you actually only see a +very simple structure which is + + align:start position:0% +very simple structure which is + + + align:start position:0% +very simple structure which is +oscillation frequency of Omega T and + + align:start position:0% +oscillation frequency of Omega T and + + + align:start position:0% +oscillation frequency of Omega T and +that means at large T okay the in the + + align:start position:0% +that means at large T okay the in the + + + align:start position:0% +that means at large T okay the in the +beginning the system will not like it + + align:start position:0% +beginning the system will not like it + + + align:start position:0% +beginning the system will not like it +you drive it and little system turn like + + align:start position:0% +you drive it and little system turn like + + + align:start position:0% +you drive it and little system turn like +it like if I go and strike you in the + + align:start position:0% +it like if I go and strike you in the + + + align:start position:0% +it like if I go and strike you in the +beginning you would not like it right + + align:start position:0% +beginning you would not like it right + + + align:start position:0% +beginning you would not like it right +maybe and if I shake it long enough and + + align:start position:0% +maybe and if I shake it long enough and + + + align:start position:0% +maybe and if I shake it long enough and +come on okay fine I accept that okay so + + align:start position:0% +come on okay fine I accept that okay so + + + align:start position:0% +come on okay fine I accept that okay so +that is actually what is going to happen + + align:start position:0% +that is actually what is going to happen + + + align:start position:0% +that is actually what is going to happen +to the system okay so now I would like + + align:start position:0% +to the system okay so now I would like + + + align:start position:0% +to the system okay so now I would like +to go through a short demonstration + + align:start position:0% +to go through a short demonstration + + + align:start position:0% +to go through a short demonstration +which is actually the Elkhart which you + + align:start position:0% +which is actually the Elkhart which you + + + align:start position:0% +which is actually the Elkhart which you +see before there's a mass and there are + + align:start position:0% +see before there's a mass and there are + + + align:start position:0% +see before there's a mass and there are +two springs in the near front and the + + align:start position:0% +two springs in the near front and the + + + align:start position:0% +two springs in the near front and the +back of this cart and of course judo I + + align:start position:0% +back of this cart and of course judo I + + + align:start position:0% +back of this cart and of course judo I +will turn on the air so that I make the + + align:start position:0% +will turn on the air so that I make the + + + align:start position:0% +will turn on the air so that I make the +friction smolder but actually still + + align:start position:0% +friction smolder but actually still + + + align:start position:0% +friction smolder but actually still +there are some still some residual + + align:start position:0% +there are some still some residual + + + align:start position:0% +there are some still some residual +friction okay and you will see that this + + align:start position:0% +friction okay and you will see that this + + + align:start position:0% +friction okay and you will see that this +this mass is actually oscillating back + + align:start position:0% +this mass is actually oscillating back + + + align:start position:0% +this mass is actually oscillating back +and forth okay and the the amplitude can + + align:start position:0% +and forth okay and the the amplitude can + + + align:start position:0% +and forth okay and the the amplitude can +become smaller and smaller as a function + + align:start position:0% +become smaller and smaller as a function + + + align:start position:0% +become smaller and smaller as a function +of time okay now in the right hand side + + align:start position:0% +of time okay now in the right hand side + + + align:start position:0% +of time okay now in the right hand side +I have a motor which is actually can + + align:start position:0% +I have a motor which is actually can + + + align:start position:0% +I have a motor which is actually can +drive this I can actually shorten over + + align:start position:0% +drive this I can actually shorten over + + + align:start position:0% +drive this I can actually shorten over +or increase the length of the right hand + + align:start position:0% +or increase the length of the right hand + + + align:start position:0% +or increase the length of the right hand +side string then actually I actually + + align:start position:0% +side string then actually I actually + + + align:start position:0% +side string then actually I actually +introduce a driving force by the right + + align:start position:0% +introduce a driving force by the right + + + align:start position:0% +introduce a driving force by the right +hand side motor if I turn it down this + + align:start position:0% +hand side motor if I turn it down this + + + align:start position:0% +hand side motor if I turn it down this +is what what is going to happen okay so + + align:start position:0% +is what what is going to happen okay so + + + align:start position:0% +is what what is going to happen okay so +you can see now this motor is actually + + align:start position:0% +you can see now this motor is actually + + + align:start position:0% +you can see now this motor is actually +going back and forth right and it has a + + align:start position:0% +going back and forth right and it has a + + + align:start position:0% +going back and forth right and it has a +slightly higher frequency + + align:start position:0% +slightly higher frequency + + + align:start position:0% +slightly higher frequency +compared to the natural frequency right + + align:start position:0% +compared to the natural frequency right + + + align:start position:0% +compared to the natural frequency right +so they the frequency of the motor is + + align:start position:0% +so they the frequency of the motor is + + + align:start position:0% +so they the frequency of the motor is +higher okay then you can see that huh + + align:start position:0% +higher okay then you can see that huh + + + align:start position:0% +higher okay then you can see that huh +this mode this this cart is actually + + align:start position:0% +this mode this this cart is actually + + + align:start position:0% +this mode this this cart is actually +oscillating but you can see that + + align:start position:0% +oscillating but you can see that + + + align:start position:0% +oscillating but you can see that +sometimes it pause and sometimes it + + align:start position:0% +sometimes it pause and sometimes it + + + align:start position:0% +sometimes it pause and sometimes it +moves faster right it's actually not you + + align:start position:0% +moves faster right it's actually not you + + + align:start position:0% +moves faster right it's actually not you +see so you can see that it's actually + + align:start position:0% +see so you can see that it's actually + + + align:start position:0% +see so you can see that it's actually +moving and it stopped a little bit and + + align:start position:0% +moving and it stopped a little bit and + + + align:start position:0% +moving and it stopped a little bit and +because there are a superposition of two + + align:start position:0% +because there are a superposition of two + + + align:start position:0% +because there are a superposition of two +different kinds of oscillation + + align:start position:0% +different kinds of oscillation + + + align:start position:0% +different kinds of oscillation +oscillating functions hang interpret you + + align:start position:0% +oscillating functions hang interpret you + + + align:start position:0% +oscillating functions hang interpret you +can see that now it got slowed down and + + align:start position:0% +can see that now it got slowed down and + + + align:start position:0% +can see that now it got slowed down and +it becomes faster and the slower and + + align:start position:0% +it becomes faster and the slower and + + + align:start position:0% +it becomes faster and the slower and +faster but eventually if we wait long + + align:start position:0% +faster but eventually if we wait long + + + align:start position:0% +faster but eventually if we wait long +enough okay if we were only now what is + + align:start position:0% +enough okay if we were only now what is + + + align:start position:0% +enough okay if we were only now what is +going to happen what is going to happen + + align:start position:0% +going to happen what is going to happen + + + align:start position:0% +going to happen what is going to happen +if we wait long enough + + align:start position:0% + + + + align:start position:0% + +exactly so basically if you wait long + + align:start position:0% +exactly so basically if you wait long + + + align:start position:0% +exactly so basically if you wait long +enough as you said you were actually + + align:start position:0% +enough as you said you were actually + + + align:start position:0% +enough as you said you were actually +just oscillate at the frequency of the + + align:start position:0% +just oscillate at the frequency of the + + + align:start position:0% +just oscillate at the frequency of the +driving force you can see that this this + + align:start position:0% +driving force you can see that this this + + + align:start position:0% +driving force you can see that this this +motion is really look 3d peas are right + + align:start position:0% +motion is really look 3d peas are right + + + align:start position:0% +motion is really look 3d peas are right +sometimes they stop and sometimes they + + align:start position:0% +sometimes they stop and sometimes they + + + align:start position:0% +sometimes they stop and sometimes they +actually continue to move and are you + + align:start position:0% +actually continue to move and are you + + + align:start position:0% +actually continue to move and are you +surprised + + align:start position:0% + + + + align:start position:0% + +probably you are not surprised anymore + + align:start position:0% +probably you are not surprised anymore + + + align:start position:0% +probably you are not surprised anymore +right because we know mass is the + + align:start position:0% +right because we know mass is the + + + align:start position:0% +right because we know mass is the +language to describe the nature right + + align:start position:0% +language to describe the nature right + + + align:start position:0% +language to describe the nature right +and indeed ypres did this kind of + + align:start position:0% +and indeed ypres did this kind of + + + align:start position:0% +and indeed ypres did this kind of +behavior that's really pretty cool okay + + align:start position:0% +behavior that's really pretty cool okay + + + align:start position:0% +behavior that's really pretty cool okay +in order to help you to learn a bit how + + align:start position:0% +in order to help you to learn a bit how + + + align:start position:0% +in order to help you to learn a bit how +to actually translate a physical + + align:start position:0% +to actually translate a physical + + + align:start position:0% +to actually translate a physical +situation into mathematics what I am + + align:start position:0% +situation into mathematics what I am + + + align:start position:0% +situation into mathematics what I am +going to do is to introduce you another + + align:start position:0% +going to do is to introduce you another + + + align:start position:0% +going to do is to introduce you another +example so that actually we can actually + + align:start position:0% +example so that actually we can actually + + + align:start position:0% +example so that actually we can actually +solve it together so now I would like to + + align:start position:0% +solve it together so now I would like to + + + align:start position:0% +solve it together so now I would like to +drive a pendulum + + align:start position:0% + + + + align:start position:0% + +okay so I prepare at a pendulum at time + + align:start position:0% +okay so I prepare at a pendulum at time + + + align:start position:0% +okay so I prepare at a pendulum at time +equal to zero okay + + align:start position:0% +equal to zero okay + + + align:start position:0% +equal to zero okay +this is a string attached to a ball with + + align:start position:0% +this is a string attached to a ball with + + + align:start position:0% +this is a string attached to a ball with +mass equal to M okay and the length of + + align:start position:0% +mass equal to M okay and the length of + + + align:start position:0% +mass equal to M okay and the length of +the string says should L and the angle + + align:start position:0% +the string says should L and the angle + + + align:start position:0% +the string says should L and the angle +between the vertical direction and the + + align:start position:0% +between the vertical direction and the + + + align:start position:0% +between the vertical direction and the +string the direction of the string is + + align:start position:0% +string the direction of the string is + + + align:start position:0% +string the direction of the string is +Sita okay and of course I can actually + + align:start position:0% +Sita okay and of course I can actually + + + align:start position:0% +Sita okay and of course I can actually +give you an initial condition X initial + + align:start position:0% +give you an initial condition X initial + + + align:start position:0% +give you an initial condition X initial +which is actually measured which is fed + + align:start position:0% +which is actually measured which is fed + + + align:start position:0% +which is actually measured which is fed +to the vertical direction okay and at + + align:start position:0% +to the vertical direction okay and at + + + align:start position:0% +to the vertical direction okay and at +time equal to T okay this is actually + + align:start position:0% +time equal to T okay this is actually + + + align:start position:0% +time equal to T okay this is actually +the original vertical direction the + + align:start position:0% +the original vertical direction the + + + align:start position:0% +the original vertical direction the +original vertical direction the same as + + align:start position:0% +original vertical direction the same as + + + align:start position:0% +original vertical direction the same as +this dash line okay and I can actually + + align:start position:0% +this dash line okay and I can actually + + + align:start position:0% +this dash line okay and I can actually +move this the the top of this stream + + align:start position:0% +move this the the top of this stream + + + align:start position:0% +move this the the top of this stream +back and forth to some position and of + + align:start position:0% +back and forth to some position and of + + + align:start position:0% +back and forth to some position and of +course the string is still connect is + + align:start position:0% +course the string is still connect is + + + align:start position:0% +course the string is still connect is +connected to the ball and and this + + align:start position:0% +connected to the ball and and this + + + align:start position:0% +connected to the ball and and this +system is they should be driven from the + + align:start position:0% +system is they should be driven from the + + + align:start position:0% +system is they should be driven from the +top by Yun Jie's Han so Yoon ji says + + align:start position:0% +top by Yun Jie's Han so Yoon ji says + + + align:start position:0% +top by Yun Jie's Han so Yoon ji says +she's shaking this assistant from the + + align:start position:0% +she's shaking this assistant from the + + + align:start position:0% +she's shaking this assistant from the +top okay and I do it really nicely so + + align:start position:0% +top okay and I do it really nicely so + + + align:start position:0% +top okay and I do it really nicely so +basically I define that the displacement + + align:start position:0% +basically I define that the displacement + + + align:start position:0% +basically I define that the displacement +T as a function of time is equal to + + align:start position:0% +T as a function of time is equal to + + + align:start position:0% +T as a function of time is equal to +Delta sine Omega DT okay so that is + + align:start position:0% +Delta sine Omega DT okay so that is + + + align:start position:0% +Delta sine Omega DT okay so that is +actually what I'm going to do okay and I + + align:start position:0% +actually what I'm going to do okay and I + + + align:start position:0% +actually what I'm going to do okay and I +would like to see what is going to + + align:start position:0% +would like to see what is going to + + + align:start position:0% +would like to see what is going to +happen to this pendulum okay so a pseudo + + align:start position:0% +happen to this pendulum okay so a pseudo + + + align:start position:0% +happen to this pendulum okay so a pseudo +the first step okay towards solving this + + align:start position:0% +the first step okay towards solving this + + + align:start position:0% +the first step okay towards solving this +problem is to define a coordinate system + + align:start position:0% +problem is to define a coordinate system + + + align:start position:0% +problem is to define a coordinate system +right so what is actually the coordinate + + align:start position:0% +right so what is actually the coordinate + + + align:start position:0% +right so what is actually the coordinate +system I am going to use so now I define + + align:start position:0% +system I am going to use so now I define + + + align:start position:0% +system I am going to use so now I define +pointing upward to be Y I define the + + align:start position:0% +pointing upward to be Y I define the + + + align:start position:0% +pointing upward to be Y I define the +vertical horizontal direction pointing + + align:start position:0% +vertical horizontal direction pointing + + + align:start position:0% +vertical horizontal direction pointing +to + + align:start position:0% +to + + + align:start position:0% +to +right hand side with the port to be X + + align:start position:0% +right hand side with the port to be X + + + align:start position:0% +right hand side with the port to be X +okay so that's not good enough I still + + align:start position:0% +okay so that's not good enough I still + + + align:start position:0% +okay so that's not good enough I still +need the origin right so now I also + + align:start position:0% +need the origin right so now I also + + + align:start position:0% +need the origin right so now I also +define my origin to be the original + + align:start position:0% +define my origin to be the original + + + align:start position:0% +define my origin to be the original +position of the ball when this is + + align:start position:0% +position of the ball when this is + + + align:start position:0% +position of the ball when this is +actually temperate the vertical which is + + align:start position:0% +actually temperate the vertical which is + + + align:start position:0% +actually temperate the vertical which is +actually completely at rest before I do + + align:start position:0% +actually completely at rest before I do + + + align:start position:0% +actually completely at rest before I do +the experiment right so that is actually + + align:start position:0% +the experiment right so that is actually + + + align:start position:0% +the experiment right so that is actually +the equilibrium position of this system + + align:start position:0% +the equilibrium position of this system + + + align:start position:0% +the equilibrium position of this system +actually okay then I define here to be + + align:start position:0% +actually okay then I define here to be + + + align:start position:0% +actually okay then I define here to be +zero zero okay so once I have not + + align:start position:0% +zero zero okay so once I have not + + + align:start position:0% +zero zero okay so once I have not +defined I can now express the position + + align:start position:0% +defined I can now express the position + + + align:start position:0% +defined I can now express the position +of this math mess or dispo to be X T and + + align:start position:0% +of this math mess or dispo to be X T and + + + align:start position:0% +of this math mess or dispo to be X T and +Y T okay and see what we are going to + + align:start position:0% +Y T okay and see what we are going to + + + align:start position:0% +Y T okay and see what we are going to +get of course as usual we are going to + + align:start position:0% +get of course as usual we are going to + + + align:start position:0% +get of course as usual we are going to +analyze the force acting forces as we + + align:start position:0% +analyze the force acting forces as we + + + align:start position:0% +analyze the force acting forces as we +are getting under on this board right so + + align:start position:0% +are getting under on this board right so + + + align:start position:0% +are getting under on this board right so +therefore as usual we will draw a force + + align:start position:0% +therefore as usual we will draw a force + + + align:start position:0% +therefore as usual we will draw a force +diagram okay so basically you have the + + align:start position:0% +diagram okay so basically you have the + + + align:start position:0% +diagram okay so basically you have the +magneto mass here and that you have I + + align:start position:0% +magneto mass here and that you have I + + + align:start position:0% +magneto mass here and that you have I +should be a swift actually two force + + align:start position:0% +should be a swift actually two force + + + align:start position:0% +should be a swift actually two force +acting on this bit of mass or a little + + align:start position:0% +acting on this bit of mass or a little + + + align:start position:0% +acting on this bit of mass or a little +ball this is FG pointing down where is + + align:start position:0% +ball this is FG pointing down where is + + + align:start position:0% +ball this is FG pointing down where is +the gravitational force and not + + align:start position:0% +the gravitational force and not + + + align:start position:0% +the gravitational force and not +essentially equal to minus mg Y okay and + + align:start position:0% +essentially equal to minus mg Y okay and + + + align:start position:0% +essentially equal to minus mg Y okay and +there's also a string tension T okay + + align:start position:0% +there's also a string tension T okay + + + align:start position:0% +there's also a string tension T okay +since we have this definition of Sita + + align:start position:0% +since we have this definition of Sita + + + align:start position:0% +since we have this definition of Sita +here basically I have the T which is + + align:start position:0% +here basically I have the T which is + + + align:start position:0% +here basically I have the T which is +actually pointing to the upper left + + align:start position:0% +actually pointing to the upper left + + + align:start position:0% +actually pointing to the upper left +direction of the board okay and of + + align:start position:0% +direction of the board okay and of + + + align:start position:0% +direction of the board okay and of +course don't forget issue there there is + + align:start position:0% +course don't forget issue there there is + + + align:start position:0% +course don't forget issue there there is +a third force which is actually F track + + align:start position:0% + + + + align:start position:0% + +okay f track is actually equal to minus + + align:start position:0% +okay f track is actually equal to minus + + + align:start position:0% +okay f track is actually equal to minus +B X dot in the x-direction + + align:start position:0% +B X dot in the x-direction + + + align:start position:0% +B X dot in the x-direction +okay now I would like to write down the + + align:start position:0% +okay now I would like to write down the + + + align:start position:0% +okay now I would like to write down the +expression for also the string tension P + + align:start position:0% +expression for also the string tension P + + + align:start position:0% +expression for also the string tension P +the P is actually equal to minus T sine + + align:start position:0% +the P is actually equal to minus T sine + + + align:start position:0% +the P is actually equal to minus T sine +theta in the X direction right because + + align:start position:0% +theta in the X direction right because + + + align:start position:0% +theta in the X direction right because +the T is pointing to upper lapped + + align:start position:0% +the T is pointing to upper lapped + + + align:start position:0% +the T is pointing to upper lapped +direction right so therefore the + + align:start position:0% +direction right so therefore the + + + align:start position:0% +direction right so therefore the +position to X direction will be minus + + align:start position:0% +position to X direction will be minus + + + align:start position:0% +position to X direction will be minus +sine theta and the price T cosine theta + + align:start position:0% +sine theta and the price T cosine theta + + + align:start position:0% +sine theta and the price T cosine theta +in the Y direction right because the + + align:start position:0% +in the Y direction right because the + + + align:start position:0% +in the Y direction right because the +tension is actually pointing up that + + align:start position:0% +tension is actually pointing up that + + + align:start position:0% +tension is actually pointing up that +okay as usual this is actually pretty + + align:start position:0% +okay as usual this is actually pretty + + + align:start position:0% +okay as usual this is actually pretty +complicated to solve I have this cosine + + align:start position:0% +complicated to solve I have this cosine + + + align:start position:0% +complicated to solve I have this cosine +I have this sign there right so what I'm + + align:start position:0% +I have this sign there right so what I'm + + + align:start position:0% +I have this sign there right so what I'm +going to do is to assume that the this + + align:start position:0% +going to do is to assume that the this + + + align:start position:0% +going to do is to assume that the this +angle theta is very small okay as usual + + align:start position:0% +angle theta is very small okay as usual + + + align:start position:0% +angle theta is very small okay as usual +okay so I will take small angle + + align:start position:0% +okay so I will take small angle + + + align:start position:0% +okay so I will take small angle +approximation then basically you have + + align:start position:0% +approximation then basically you have + + + align:start position:0% +approximation then basically you have +sine theta roughly to be equal to theta + + align:start position:0% +sine theta roughly to be equal to theta + + + align:start position:0% +sine theta roughly to be equal to theta +and that is actually equal to what equal + + align:start position:0% +and that is actually equal to what equal + + + align:start position:0% +and that is actually equal to what equal +to here basically you can actually + + align:start position:0% +to here basically you can actually + + + align:start position:0% +to here basically you can actually +calculate what will be the theta right + + align:start position:0% +calculate what will be the theta right + + + align:start position:0% +calculate what will be the theta right +okay the CETA the sine theta or theta + + align:start position:0% +okay the CETA the sine theta or theta + + + align:start position:0% +okay the CETA the sine theta or theta +will be equal to X minus P divided by L + + align:start position:0% +will be equal to X minus P divided by L + + + align:start position:0% +will be equal to X minus P divided by L +right and of course taking a small angle + + align:start position:0% +right and of course taking a small angle + + + align:start position:0% +right and of course taking a small angle +approximation will bring cosine theta to + + align:start position:0% +approximation will bring cosine theta to + + + align:start position:0% +approximation will bring cosine theta to +be 1 okay then after this approximation + + align:start position:0% +be 1 okay then after this approximation + + + align:start position:0% +be 1 okay then after this approximation +my T will become minus T X minus D + + align:start position:0% +my T will become minus T X minus D + + + align:start position:0% +my T will become minus T X minus D +divided by L in the X direction + + align:start position:0% +divided by L in the X direction + + + align:start position:0% +divided by L in the X direction +press T in the y-direction okay because + + align:start position:0% +press T in the y-direction okay because + + + align:start position:0% +press T in the y-direction okay because +sine theta is replaced by this + + align:start position:0% +sine theta is replaced by this + + + align:start position:0% +sine theta is replaced by this +approximated value cosine theta is a + + align:start position:0% +approximated value cosine theta is a + + + align:start position:0% +approximated value cosine theta is a +should be pressed by what okay + + align:start position:0% +should be pressed by what okay + + + align:start position:0% +should be pressed by what okay +any questions + + align:start position:0% + + + + align:start position:0% + +so I can ah + + align:start position:0% +so I can ah + + + align:start position:0% +so I can ah +this theater ah is a constant yeah I was + + align:start position:0% +this theater ah is a constant yeah I was + + + align:start position:0% +this theater ah is a constant yeah I was +going too fast so this is a constant I + + align:start position:0% +going too fast so this is a constant I + + + align:start position:0% +going too fast so this is a constant I +hope my other MP - okay yes it's only in + + align:start position:0% +hope my other MP - okay yes it's only in + + + align:start position:0% +hope my other MP - okay yes it's only in +the director X direction so I'm only + + align:start position:0% +the director X direction so I'm only + + + align:start position:0% +the director X direction so I'm only +trying to actually move this point back + + align:start position:0% +trying to actually move this point back + + + align:start position:0% +trying to actually move this point back +and forth horizontally okay okay so now + + align:start position:0% +and forth horizontally okay okay so now + + + align:start position:0% +and forth horizontally okay okay so now +I have all the components t FG f Jack + + align:start position:0% +I have all the components t FG f Jack + + + align:start position:0% +I have all the components t FG f Jack +okay and of course you can see that I + + align:start position:0% +okay and of course you can see that I + + + align:start position:0% +okay and of course you can see that I +already ignore the drag force in the + + align:start position:0% +already ignore the drag force in the + + + align:start position:0% +already ignore the drag force in the +y-direction right from that formula okay + + align:start position:0% +y-direction right from that formula okay + + + align:start position:0% +y-direction right from that formula okay +because I'm only considering the system + + align:start position:0% +because I'm only considering the system + + + align:start position:0% +because I'm only considering the system +to be moving in the X direction okay + + align:start position:0% +to be moving in the X direction okay + + + align:start position:0% +to be moving in the X direction okay +therefore I can now collect all the + + align:start position:0% +therefore I can now collect all the + + + align:start position:0% +therefore I can now collect all the +turns in the X direction okay basically + + align:start position:0% +turns in the X direction okay basically + + + align:start position:0% +turns in the X direction okay basically +you will have em X double dot this is + + align:start position:0% +you will have em X double dot this is + + + align:start position:0% +you will have em X double dot this is +equal to minus P X dot okay which is + + align:start position:0% +equal to minus P X dot okay which is + + + align:start position:0% +equal to minus P X dot okay which is +actually I'm in front the drag force + + align:start position:0% +actually I'm in front the drag force + + + align:start position:0% +actually I'm in front the drag force +okay - T X minus T divided by L this is + + align:start position:0% +okay - T X minus T divided by L this is + + + align:start position:0% +okay - T X minus T divided by L this is +actually coming from this term in the X + + align:start position:0% +actually coming from this term in the X + + + align:start position:0% +actually coming from this term in the X +direction let's look at also the Y + + align:start position:0% +direction let's look at also the Y + + + align:start position:0% +direction let's look at also the Y +direction and y double dot will be equal + + align:start position:0% +direction and y double dot will be equal + + + align:start position:0% +direction and y double dot will be equal +to minus mg plus T right the minus mg is + + align:start position:0% +to minus mg plus T right the minus mg is + + + align:start position:0% +to minus mg plus T right the minus mg is +from the publication of force and this T + + align:start position:0% +from the publication of force and this T + + + align:start position:0% +from the publication of force and this T +is coming from the Y component of the + + align:start position:0% +is coming from the Y component of the + + + align:start position:0% +is coming from the Y component of the +stream tension okay + + align:start position:0% +stream tension okay + + + align:start position:0% +stream tension okay +and of course since we are taking as + + align:start position:0% +and of course since we are taking as + + + align:start position:0% +and of course since we are taking as +very small angle approximation there + + align:start position:0% +very small angle approximation there + + + align:start position:0% +very small angle approximation there +will be no vertical motion right yes + + align:start position:0% + + + + align:start position:0% + +yeah so so actually in this case they + + align:start position:0% +yeah so so actually in this case they + + + align:start position:0% +yeah so so actually in this case they +happen to be exactly the same and and + + align:start position:0% +happen to be exactly the same and and + + + align:start position:0% +happen to be exactly the same and and +what I care is actually the cosine theta + + align:start position:0% +what I care is actually the cosine theta + + + align:start position:0% +what I care is actually the cosine theta +otherwise I would have to deal with + + align:start position:0% +otherwise I would have to deal with + + + align:start position:0% +otherwise I would have to deal with +cosine theta and also this white upper + + align:start position:0% +cosine theta and also this white upper + + + align:start position:0% +cosine theta and also this white upper +dog will not be equal to zero right + + align:start position:0% +dog will not be equal to zero right + + + align:start position:0% +dog will not be equal to zero right +which is what I'm going to assume here + + align:start position:0% +which is what I'm going to assume here + + + align:start position:0% +which is what I'm going to assume here +okay good question so the question was + + align:start position:0% +okay good question so the question was + + + align:start position:0% +okay good question so the question was +why do I need to take a person because I + + align:start position:0% +why do I need to take a person because I + + + align:start position:0% +why do I need to take a person because I +want to get rid of cause I see okay so + + align:start position:0% +want to get rid of cause I see okay so + + + align:start position:0% +want to get rid of cause I see okay so +now I from this y direction I can solve + + align:start position:0% +now I from this y direction I can solve + + + align:start position:0% +now I from this y direction I can solve +T will be equal to and G right because + + align:start position:0% +T will be equal to and G right because + + + align:start position:0% +T will be equal to and G right because +there's I assume that there's no y + + align:start position:0% +there's I assume that there's no y + + + align:start position:0% +there's I assume that there's no y +direction motion then I can conclude + + align:start position:0% +direction motion then I can conclude + + + align:start position:0% +direction motion then I can conclude +that okay originally I don't know what + + align:start position:0% +that okay originally I don't know what + + + align:start position:0% +that okay originally I don't know what +this is you the string tension right + + align:start position:0% +this is you the string tension right + + + align:start position:0% +this is you the string tension right +it's denoted by T now from this second + + align:start position:0% +it's denoted by T now from this second + + + align:start position:0% +it's denoted by T now from this second +equation I can conclude that T will be + + align:start position:0% +equation I can conclude that T will be + + + align:start position:0% +equation I can conclude that T will be +equal to ng okay which is the + + align:start position:0% +equal to ng okay which is the + + + align:start position:0% +equal to ng okay which is the +gravitational force okay then once I + + align:start position:0% +gravitational force okay then once I + + + align:start position:0% +gravitational force okay then once I +have that I can go back to to X + + align:start position:0% +have that I can go back to to X + + + align:start position:0% +have that I can go back to to X +direction okay basically I get an X + + align:start position:0% +direction okay basically I get an X + + + align:start position:0% +direction okay basically I get an X +double dot this is equal to minus P X + + align:start position:0% +double dot this is equal to minus P X + + + align:start position:0% +double dot this is equal to minus P X +dot minus n G over L X minus T + + align:start position:0% + + + + align:start position:0% + +everything is working very well and I + + align:start position:0% +everything is working very well and I + + + align:start position:0% +everything is working very well and I +just have to read it write down the T + + align:start position:0% +just have to read it write down the T + + + align:start position:0% +just have to read it write down the T +and the X explicitly okay the team + + align:start position:0% +and the X explicitly okay the team + + + align:start position:0% +and the X explicitly okay the team +function explicitly what is d D is just + + align:start position:0% +function explicitly what is d D is just + + + align:start position:0% +function explicitly what is d D is just +a reminder Delta sine Omega DT right + + align:start position:0% +a reminder Delta sine Omega DT right + + + align:start position:0% +a reminder Delta sine Omega DT right +okay so I will product that into that + + align:start position:0% +okay so I will product that into that + + + align:start position:0% +okay so I will product that into that +equation and also I will bring all the + + align:start position:0% +equation and also I will bring all the + + + align:start position:0% +equation and also I will bring all the +turns I will bring all the terms with + + align:start position:0% +turns I will bring all the terms with + + + align:start position:0% +turns I will bring all the terms with +82x Toula laugh and sigh okay just to + + align:start position:0% +82x Toula laugh and sigh okay just to + + + align:start position:0% +82x Toula laugh and sigh okay just to +match my my convention okay all right so + + align:start position:0% +match my my convention okay all right so + + + align:start position:0% +match my my convention okay all right so +now I will be able to get a visa and X + + align:start position:0% +now I will be able to get a visa and X + + + align:start position:0% +now I will be able to get a visa and X +double dot plus P X dot + + align:start position:0% +double dot plus P X dot + + + align:start position:0% +double dot plus P X dot +pass and G over L X and that is actually + + align:start position:0% +pass and G over L X and that is actually + + + align:start position:0% +pass and G over L X and that is actually +equal to n G over L T okay and this is + + align:start position:0% +equal to n G over L T okay and this is + + + align:start position:0% +equal to n G over L T okay and this is +equal to n G over L Delta sine Omega T + + align:start position:0% +equal to n G over L Delta sine Omega T + + + align:start position:0% +equal to n G over L Delta sine Omega T +right so basically I collect all the + + align:start position:0% +right so basically I collect all the + + + align:start position:0% +right so basically I collect all the +turns put it to a lap inside and I write + + align:start position:0% +turns put it to a lap inside and I write + + + align:start position:0% +turns put it to a lap inside and I write +down T explicitly okay which is this + + align:start position:0% +down T explicitly okay which is this + + + align:start position:0% +down T explicitly okay which is this +okay then I can divide everything by an + + align:start position:0% +okay then I can divide everything by an + + + align:start position:0% +okay then I can divide everything by an +end then I get n X double dot plus P + + align:start position:0% +end then I get n X double dot plus P + + + align:start position:0% +end then I get n X double dot plus P +over N X dot plus G over L X and that + + align:start position:0% +over N X dot plus G over L X and that + + + align:start position:0% +over N X dot plus G over L X and that +will be equal to G over L Delta sine + + align:start position:0% +will be equal to G over L Delta sine + + + align:start position:0% +will be equal to G over L Delta sine +Omega T now course as usual I would + + align:start position:0% +Omega T now course as usual I would + + + align:start position:0% +Omega T now course as usual I would +define this to be comma define this to + + align:start position:0% +define this to be comma define this to + + + align:start position:0% +define this to be comma define this to +be Omega 0 square I will define this to + + align:start position:0% +be Omega 0 square I will define this to + + + align:start position:0% +be Omega 0 square I will define this to +pf0 + + align:start position:0% +pf0 + + + align:start position:0% +pf0 +and which is equal to Omega 0 square + + align:start position:0% +and which is equal to Omega 0 square + + + align:start position:0% +and which is equal to Omega 0 square +Delta ok happen to be good like that and + + align:start position:0% +Delta ok happen to be good like that and + + + align:start position:0% +Delta ok happen to be good like that and +then this HDPE can X double dot plus + + align:start position:0% +then this HDPE can X double dot plus + + + align:start position:0% +then this HDPE can X double dot plus +gamma X dot plus Omega 0 square X equal + + align:start position:0% +gamma X dot plus Omega 0 square X equal + + + align:start position:0% +gamma X dot plus Omega 0 square X equal +to F 0 sine Omega T T are going too fast + + align:start position:0% +to F 0 sine Omega T T are going too fast + + + align:start position:0% +to F 0 sine Omega T T are going too fast +okay everybody is following so we see + + align:start position:0% +okay everybody is following so we see + + + align:start position:0% +okay everybody is following so we see +the half this equation I know that I + + align:start position:0% +the half this equation I know that I + + + align:start position:0% +the half this equation I know that I +know this equation right because we have + + align:start position:0% +know this equation right because we have + + + align:start position:0% +know this equation right because we have +just solved that a few minutes ago right + + align:start position:0% +just solved that a few minutes ago right + + + align:start position:0% +just solved that a few minutes ago right +therefore I know immediately what would + + align:start position:0% +therefore I know immediately what would + + + align:start position:0% +therefore I know immediately what would +be the solution the solution is here + + align:start position:0% +be the solution the solution is here + + + align:start position:0% +be the solution the solution is here +already right I have a Omega D and the + + align:start position:0% +already right I have a Omega D and the + + + align:start position:0% +already right I have a Omega D and the +10 tangents Delta the functional points + + align:start position:0% +10 tangents Delta the functional points + + + align:start position:0% +10 tangents Delta the functional points +there therefore I can now write down + + align:start position:0% +there therefore I can now write down + + + align:start position:0% +there therefore I can now write down +what would be the a ok so a is actually + + align:start position:0% +what would be the a ok so a is actually + + + align:start position:0% +what would be the a ok so a is actually +just equal to F 0 divided by square root + + align:start position:0% +just equal to F 0 divided by square root + + + align:start position:0% +just equal to F 0 divided by square root +of Omega 0 square minus or me + + align:start position:0% +of Omega 0 square minus or me + + + align:start position:0% +of Omega 0 square minus or me +d square squared plus Omega P square + + align:start position:0% +d square squared plus Omega P square + + + align:start position:0% +d square squared plus Omega P square +gamma square okay okay so now the + + align:start position:0% +gamma square okay okay so now the + + + align:start position:0% +gamma square okay okay so now the +question is what does the result should + + align:start position:0% +question is what does the result should + + + align:start position:0% +question is what does the result should +be me I have this function okay I have + + align:start position:0% +be me I have this function okay I have + + + align:start position:0% +be me I have this function okay I have +that function tangent is soft it's + + align:start position:0% +that function tangent is soft it's + + + align:start position:0% +that function tangent is soft it's +actually the amplitude of the steady + + align:start position:0% +actually the amplitude of the steady + + + align:start position:0% +actually the amplitude of the steady +state solution and also the phase + + align:start position:0% +state solution and also the phase + + + align:start position:0% +state solution and also the phase +difference between the drag force phase + + align:start position:0% +difference between the drag force phase + + + align:start position:0% +difference between the drag force phase +and the steady state oscillation phase + + align:start position:0% +and the steady state oscillation phase + + + align:start position:0% +and the steady state oscillation phase +right so that issue that the among of + + align:start position:0% +right so that issue that the among of + + + align:start position:0% +right so that issue that the among of +lag and the size of the amplitude right + + align:start position:0% +lag and the size of the amplitude right + + + align:start position:0% +lag and the size of the amplitude right +but I but through this equation is very + + align:start position:0% +but I but through this equation is very + + + align:start position:0% +but I but through this equation is very +difficult to understand right so what + + align:start position:0% +difficult to understand right so what + + + align:start position:0% +difficult to understand right so what +I'm going to do is to take some limit so + + align:start position:0% +I'm going to do is to take some limit so + + + align:start position:0% +I'm going to do is to take some limit so +that actually we can help you to + + align:start position:0% +that actually we can help you to + + + align:start position:0% +that actually we can help you to +understand what is going down so suppose + + align:start position:0% +understand what is going down so suppose + + + align:start position:0% +understand what is going down so suppose +I assume that Omega T goes to zero okay + + align:start position:0% +I assume that Omega T goes to zero okay + + + align:start position:0% +I assume that Omega T goes to zero okay +so what does I mean this is Yun Jie's + + align:start position:0% +so what does I mean this is Yun Jie's + + + align:start position:0% +so what does I mean this is Yun Jie's +hand and eyes moving really slowly and + + align:start position:0% +hand and eyes moving really slowly and + + + align:start position:0% +hand and eyes moving really slowly and +see what is going to happen okay + + align:start position:0% +see what is going to happen okay + + + align:start position:0% +see what is going to happen okay +if I do this okay then you will find + + align:start position:0% +if I do this okay then you will find + + + align:start position:0% +if I do this okay then you will find +that a Omega D okay since Omega T goes + + align:start position:0% +that a Omega D okay since Omega T goes + + + align:start position:0% +that a Omega D okay since Omega T goes +to zero right this is gone this is gone + + align:start position:0% +to zero right this is gone this is gone + + + align:start position:0% +to zero right this is gone this is gone +right therefore you will see that Omega + + align:start position:0% +right therefore you will see that Omega + + + align:start position:0% +right therefore you will see that Omega +a will be equal to Omega zero divided by + + align:start position:0% +a will be equal to Omega zero divided by + + + align:start position:0% +a will be equal to Omega zero divided by +the way of the F zero divided by Omega 0 + + align:start position:0% +the way of the F zero divided by Omega 0 + + + align:start position:0% +the way of the F zero divided by Omega 0 +square and that is actually equal to G + + align:start position:0% +square and that is actually equal to G + + + align:start position:0% +square and that is actually equal to G +Delta over L divided by G over L and now + + align:start position:0% +Delta over L divided by G over L and now + + + align:start position:0% +Delta over L divided by G over L and now +will give you Delta so what does that + + align:start position:0% +will give you Delta so what does that + + + align:start position:0% +will give you Delta so what does that +mean this means that if I move this + + align:start position:0% +mean this means that if I move this + + + align:start position:0% +mean this means that if I move this +thing drive this thing really slowly + + align:start position:0% +thing drive this thing really slowly + + + align:start position:0% +thing drive this thing really slowly +then the amplitude of the mass will be + + align:start position:0% +then the amplitude of the mass will be + + + align:start position:0% +then the amplitude of the mass will be +equal to how much I as you move which is + + align:start position:0% +equal to how much I as you move which is + + + align:start position:0% +equal to how much I as you move which is +total + + align:start position:0% +total + + + align:start position:0% +total +okay do get it in additional to that + + align:start position:0% +okay do get it in additional to that + + + align:start position:0% +okay do get it in additional to that +okay tangent do that since I'm taking + + align:start position:0% +okay tangent do that since I'm taking + + + align:start position:0% +okay tangent do that since I'm taking +the limit of Omega T goes to 0 therefore + + align:start position:0% +the limit of Omega T goes to 0 therefore + + + align:start position:0% +the limit of Omega T goes to 0 therefore +tangent theta will be equal to 0 and na + + align:start position:0% +tangent theta will be equal to 0 and na + + + align:start position:0% +tangent theta will be equal to 0 and na +means Delta will be equal to 0 + + align:start position:0% +means Delta will be equal to 0 + + + align:start position:0% +means Delta will be equal to 0 +any questions so that means there will + + align:start position:0% +any questions so that means there will + + + align:start position:0% +any questions so that means there will +be no phase difference that cistern have + + align:start position:0% +be no phase difference that cistern have + + + align:start position:0% +be no phase difference that cistern have +enough time to keep up with my speed ok + + align:start position:0% +enough time to keep up with my speed ok + + + align:start position:0% +enough time to keep up with my speed ok +the second limit obviously Omega T goes + + align:start position:0% +the second limit obviously Omega T goes + + + align:start position:0% +the second limit obviously Omega T goes +to infinity okay what does I mean that + + align:start position:0% +to infinity okay what does I mean that + + + align:start position:0% +to infinity okay what does I mean that +means I am going to hold this string + + align:start position:0% +means I am going to hold this string + + + align:start position:0% +means I am going to hold this string +shaking like crazy really fast okay and + + align:start position:0% +shaking like crazy really fast okay and + + + align:start position:0% +shaking like crazy really fast okay and +see what what happened okay so in that + + align:start position:0% +see what what happened okay so in that + + + align:start position:0% +see what what happened okay so in that +case you will get a Omega D and that + + align:start position:0% +case you will get a Omega D and that + + + align:start position:0% +case you will get a Omega D and that +goes to 0 because Omega T goes to + + align:start position:0% +goes to 0 because Omega T goes to + + + align:start position:0% +goes to 0 because Omega T goes to +infinity right this goes to 0 and also + + align:start position:0% +infinity right this goes to 0 and also + + + align:start position:0% +infinity right this goes to 0 and also +tangent Delta goes to infinity therefore + + align:start position:0% +tangent Delta goes to infinity therefore + + + align:start position:0% +tangent Delta goes to infinity therefore +Delta what goes to PI so that means + + align:start position:0% +Delta what goes to PI so that means + + + align:start position:0% +Delta what goes to PI so that means +there will be out of phase okay any + + align:start position:0% +there will be out of phase okay any + + + align:start position:0% +there will be out of phase okay any +questions so far in these two limits ok + + align:start position:0% +questions so far in these two limits ok + + + align:start position:0% +questions so far in these two limits ok +so what I'm going to do now is to take a + + align:start position:0% +so what I'm going to do now is to take a + + + align:start position:0% +so what I'm going to do now is to take a +small toy which I made for my son with + + align:start position:0% +small toy which I made for my son with + + + align:start position:0% +small toy which I made for my son with +one year oh now because I would like to + + align:start position:0% +one year oh now because I would like to + + + align:start position:0% +one year oh now because I would like to +him to learn waves and vibration before + + align:start position:0% +him to learn waves and vibration before + + + align:start position:0% +him to learn waves and vibration before +he goes to content right alright so I + + align:start position:0% +he goes to content right alright so I + + + align:start position:0% +he goes to content right alright so I +made this toy and he so don't get it + + align:start position:0% +made this toy and he so don't get it + + + align:start position:0% +made this toy and he so don't get it +okay + + align:start position:0% +okay + + + align:start position:0% +okay +all right so you can see now I can + + align:start position:0% +all right so you can see now I can + + + align:start position:0% +all right so you can see now I can +demonstrate what is going to happen when + + align:start position:0% +demonstrate what is going to happen when + + + align:start position:0% +demonstrate what is going to happen when +Omega is approaching to zero okay + + align:start position:0% + + + + align:start position:0% + +I'm ready to win it can you see it no + + align:start position:0% +I'm ready to win it can you see it no + + + align:start position:0% +I'm ready to win it can you see it no +it's a very exciting experiment can you + + align:start position:0% +it's a very exciting experiment can you + + + align:start position:0% +it's a very exciting experiment can you +see that you see that this is original + + align:start position:0% +see that you see that this is original + + + align:start position:0% +see that you see that this is original +vertical direction if I do it really + + align:start position:0% +vertical direction if I do it really + + + align:start position:0% +vertical direction if I do it really +really slowly okay you can see that the + + align:start position:0% +really slowly okay you can see that the + + + align:start position:0% +really slowly okay you can see that the +amplitude of the ball is actually + + align:start position:0% +amplitude of the ball is actually + + + align:start position:0% +amplitude of the ball is actually +exactly the same as the displacement I + + align:start position:0% +exactly the same as the displacement I + + + align:start position:0% +exactly the same as the displacement I +introduced right so that's actually kind + + align:start position:0% +introduced right so that's actually kind + + + align:start position:0% +introduced right so that's actually kind +of a bit obvious right okay so now let's + + align:start position:0% +of a bit obvious right okay so now let's + + + align:start position:0% +of a bit obvious right okay so now let's +see what is going to happen if I type + + align:start position:0% +see what is going to happen if I type + + + align:start position:0% +see what is going to happen if I type +this system like crazy + + align:start position:0% +this system like crazy + + + align:start position:0% +this system like crazy +okay not going up and down that's what + + align:start position:0% +okay not going up and down that's what + + + align:start position:0% +okay not going up and down that's what +makes it must be I can do maybe you can + + align:start position:0% +makes it must be I can do maybe you can + + + align:start position:0% +makes it must be I can do maybe you can +do it better faster but you can see that + + align:start position:0% +do it better faster but you can see that + + + align:start position:0% +do it better faster but you can see that +nothing happened right + + align:start position:0% +nothing happened right + + + align:start position:0% +nothing happened right +so mp2 is close to zero because what you + + align:start position:0% +so mp2 is close to zero because what you + + + align:start position:0% +so mp2 is close to zero because what you +have been doing so what you know + + align:start position:0% +have been doing so what you know + + + align:start position:0% +have been doing so what you know +disappear I mean you call cancel to each + + align:start position:0% +disappear I mean you call cancel to each + + + align:start position:0% +disappear I mean you call cancel to each +other cancelling each other right and + + align:start position:0% +other cancelling each other right and + + + align:start position:0% +other cancelling each other right and +it's actually not going to contribute to + + align:start position:0% +it's actually not going to contribute to + + + align:start position:0% +it's actually not going to contribute to +the motion of this this ball okay so now + + align:start position:0% +the motion of this this ball okay so now + + + align:start position:0% +the motion of this this ball okay so now +you can see that I can also test what is + + align:start position:0% +you can see that I can also test what is + + + align:start position:0% +you can see that I can also test what is +actually the natural frequency and what + + align:start position:0% +actually the natural frequency and what + + + align:start position:0% +actually the natural frequency and what +I'm going to do is to oscillate around + + align:start position:0% +I'm going to do is to oscillate around + + + align:start position:0% +I'm going to do is to oscillate around +the nature of frequency to see what is + + align:start position:0% +the nature of frequency to see what is + + + align:start position:0% +the nature of frequency to see what is +going to happen okay let's see what is + + align:start position:0% +going to happen okay let's see what is + + + align:start position:0% +going to happen okay let's see what is +going to happen you can see that the + + align:start position:0% +going to happen you can see that the + + + align:start position:0% +going to happen you can see that the +Delta is really small right can you see + + align:start position:0% +Delta is really small right can you see + + + align:start position:0% +Delta is really small right can you see +the tilde it's really small very small + + align:start position:0% +the tilde it's really small very small + + + align:start position:0% +the tilde it's really small very small +very small but you can see that the + + align:start position:0% +very small but you can see that the + + + align:start position:0% +very small but you can see that the +amplitude the a is huge what does that + + align:start position:0% +amplitude the a is huge what does that + + + align:start position:0% +amplitude the a is huge what does that +tell us what does that tell us + + align:start position:0% +tell us what does that tell us + + + align:start position:0% +tell us what does that tell us +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +yes we are experiencing resonance and + + align:start position:0% +yes we are experiencing resonance and + + + align:start position:0% +yes we are experiencing resonance and +also that also tells you that the system + + align:start position:0% +also that also tells you that the system + + + align:start position:0% +also that also tells you that the system +is under damped very much the Q value is + + align:start position:0% +is under damped very much the Q value is + + + align:start position:0% +is under damped very much the Q value is +very big okay so if I calculate the + + align:start position:0% +very big okay so if I calculate the + + + align:start position:0% +very big okay so if I calculate the +amplitude a okay now I can calculate the + + align:start position:0% +amplitude a okay now I can calculate the + + + align:start position:0% +amplitude a okay now I can calculate the +MP to a at natural frequency okay what + + align:start position:0% +MP to a at natural frequency okay what + + + align:start position:0% +MP to a at natural frequency okay what +I'm going to get is now I can as you + + align:start position:0% +I'm going to get is now I can as you + + + align:start position:0% +I'm going to get is now I can as you +plug in Omega T equal to omega0 okay so + + align:start position:0% +plug in Omega T equal to omega0 okay so + + + align:start position:0% +plug in Omega T equal to omega0 okay so +if I plug in Omega T Omega T equal to + + align:start position:0% +if I plug in Omega T Omega T equal to + + + align:start position:0% +if I plug in Omega T Omega T equal to +Omega 0 then what is going to happen so + + align:start position:0% +Omega 0 then what is going to happen so + + + align:start position:0% +Omega 0 then what is going to happen so +this term will cancel right so you have + + align:start position:0% +this term will cancel right so you have + + + align:start position:0% +this term will cancel right so you have +a will equal to f0 divided by Omega 0 + + align:start position:0% +a will equal to f0 divided by Omega 0 + + + align:start position:0% +a will equal to f0 divided by Omega 0 +squared Omega 0 comma right Omega T is + + align:start position:0% +squared Omega 0 comma right Omega T is + + + align:start position:0% +squared Omega 0 comma right Omega T is +now equal to Omega 0 okay and that is + + align:start position:0% +now equal to Omega 0 okay and that is + + + align:start position:0% +now equal to Omega 0 okay and that is +going to keep keep you okay so f0 is + + align:start position:0% +going to keep keep you okay so f0 is + + + align:start position:0% +going to keep keep you okay so f0 is +they should be Omega 0 square Delta + + align:start position:0% +they should be Omega 0 square Delta + + + align:start position:0% +they should be Omega 0 square Delta +divided by Omega 0 okay and 1 Omega 0 + + align:start position:0% +divided by Omega 0 okay and 1 Omega 0 + + + align:start position:0% +divided by Omega 0 okay and 1 Omega 0 +has to cancel then basically you will + + align:start position:0% +has to cancel then basically you will + + + align:start position:0% +has to cancel then basically you will +get Q times Delta okay what is Q just a + + align:start position:0% +get Q times Delta okay what is Q just a + + + align:start position:0% +get Q times Delta okay what is Q just a +reminder it's actually the ratio of + + align:start position:0% +reminder it's actually the ratio of + + + align:start position:0% +reminder it's actually the ratio of +Omega 0 and the gamma when the Q is very + + align:start position:0% +Omega 0 and the gamma when the Q is very + + + align:start position:0% +Omega 0 and the gamma when the Q is very +large what does that mean that means is + + align:start position:0% +large what does that mean that means is + + + align:start position:0% +large what does that mean that means is +so close to idealize the situation the + + align:start position:0% +so close to idealize the situation the + + + align:start position:0% +so close to idealize the situation the +drag force is very small okay + + align:start position:0% +drag force is very small okay + + + align:start position:0% +drag force is very small okay +you can see that in the example at which + + align:start position:0% +you can see that in the example at which + + + align:start position:0% +you can see that in the example at which +I have been doing right so you can see + + align:start position:0% +I have been doing right so you can see + + + align:start position:0% +I have been doing right so you can see +that ah it is really the case right so + + align:start position:0% +that ah it is really the case right so + + + align:start position:0% +that ah it is really the case right so +you can see that if my Delta is + + align:start position:0% +you can see that if my Delta is + + + align:start position:0% +you can see that if my Delta is +something like 1 centimeter right for + + align:start position:0% +something like 1 centimeter right for + + + align:start position:0% +something like 1 centimeter right for +the amplitude + + align:start position:0% +the amplitude + + + align:start position:0% +the amplitude +essentially at the order of 1 meter + + align:start position:0% +essentially at the order of 1 meter + + + align:start position:0% +essentially at the order of 1 meter +maybe what does that mean that means the + + align:start position:0% +maybe what does that mean that means the + + + align:start position:0% +maybe what does that mean that means the +queue is actually roughly 100 okay so + + align:start position:0% +queue is actually roughly 100 okay so + + + align:start position:0% +queue is actually roughly 100 okay so +you can easily even get a queue out of + + align:start position:0% +you can easily even get a queue out of + + + align:start position:0% +you can easily even get a queue out of +this experiment okay any questions so + + align:start position:0% +this experiment okay any questions so + + + align:start position:0% +this experiment okay any questions so +far + + align:start position:0% + + + + align:start position:0% + +okay that's very good so now we can go + + align:start position:0% +okay that's very good so now we can go + + + align:start position:0% +okay that's very good so now we can go +ahead and take a look at the structure + + align:start position:0% +ahead and take a look at the structure + + + align:start position:0% +ahead and take a look at the structure +of a and the Delta okay as we + + align:start position:0% +of a and the Delta okay as we + + + align:start position:0% +of a and the Delta okay as we +demonstrate it before we make sense of + + align:start position:0% +demonstrate it before we make sense of + + + align:start position:0% +demonstrate it before we make sense of +the three different kinds of situation + + align:start position:0% +the three different kinds of situation + + + align:start position:0% +the three different kinds of situation +Omega T cos of 0 Omega T goes to + + align:start position:0% +Omega T cos of 0 Omega T goes to + + + align:start position:0% +Omega T cos of 0 Omega T goes to +infinity and of course I would like to + + align:start position:0% +infinity and of course I would like to + + + align:start position:0% +infinity and of course I would like to +know the full structure of those a and + + align:start position:0% +know the full structure of those a and + + + align:start position:0% +know the full structure of those a and +Delta therefore what I'm going to do is + + align:start position:0% +Delta therefore what I'm going to do is + + + align:start position:0% +Delta therefore what I'm going to do is +to plot a Omega T ok that's a function + + align:start position:0% +to plot a Omega T ok that's a function + + + align:start position:0% +to plot a Omega T ok that's a function +of Omega T ok so what I'm going to do + + align:start position:0% +of Omega T ok so what I'm going to do + + + align:start position:0% +of Omega T ok so what I'm going to do +what I can I'm going to get is this will + + align:start position:0% +what I can I'm going to get is this will + + + align:start position:0% +what I can I'm going to get is this will +be equal to theta when Omega T goes to + + align:start position:0% +be equal to theta when Omega T goes to + + + align:start position:0% +be equal to theta when Omega T goes to +zero right we just demonstrated that + + align:start position:0% +zero right we just demonstrated that + + + align:start position:0% +zero right we just demonstrated that +right and this will increase to a large + + align:start position:0% +right and this will increase to a large + + + align:start position:0% +right and this will increase to a large +value and drop down to some two to zero + + align:start position:0% +value and drop down to some two to zero + + + align:start position:0% +value and drop down to some two to zero +when you when Omega T goes to infinity + + align:start position:0% +when you when Omega T goes to infinity + + + align:start position:0% +when you when Omega T goes to infinity +okay and you can see that this is around + + align:start position:0% +okay and you can see that this is around + + + align:start position:0% +okay and you can see that this is around +Omega zero and that you are going to get + + align:start position:0% +Omega zero and that you are going to get + + + align:start position:0% +Omega zero and that you are going to get +a huge amplitude okay at run Omega zero + + align:start position:0% +a huge amplitude okay at run Omega zero + + + align:start position:0% +a huge amplitude okay at run Omega zero +but not quite that maximises should be + + align:start position:0% +but not quite that maximises should be + + + align:start position:0% +but not quite that maximises should be +slightly smaller than Omega zero you can + + align:start position:0% +slightly smaller than Omega zero you can + + + align:start position:0% +slightly smaller than Omega zero you can +actually calculate that as a part of the + + align:start position:0% +actually calculate that as a part of the + + + align:start position:0% +actually calculate that as a part of the +homework okay so that makes sense now I + + align:start position:0% +homework okay so that makes sense now I + + + align:start position:0% +homework okay so that makes sense now I +can also press the the Delta which is + + align:start position:0% +can also press the the Delta which is + + + align:start position:0% +can also press the the Delta which is +the phase difference okay and you can + + align:start position:0% +the phase difference okay and you can + + + align:start position:0% +the phase difference okay and you can +see that this phase difference will be + + align:start position:0% +see that this phase difference will be + + + align:start position:0% +see that this phase difference will be +originally zero when the Omega T is very + + align:start position:0% +originally zero when the Omega T is very + + + align:start position:0% +originally zero when the Omega T is very +small and this is actually Omega zero I + + align:start position:0% +small and this is actually Omega zero I + + + align:start position:0% +small and this is actually Omega zero I +hope you can see it okay and this will + + align:start position:0% +hope you can see it okay and this will + + + align:start position:0% +hope you can see it okay and this will +be increasing rapidly here and + + align:start position:0% +be increasing rapidly here and + + + align:start position:0% +be increasing rapidly here and +approaching to two pi okay so that + + align:start position:0% +approaching to two pi okay so that + + + align:start position:0% +approaching to two pi okay so that +means when you are shaking this system + + align:start position:0% +means when you are shaking this system + + + align:start position:0% +means when you are shaking this system +like crazy very high frequency then the + + align:start position:0% +like crazy very high frequency then the + + + align:start position:0% +like crazy very high frequency then the +system cannot keep up with the lip speed + + align:start position:0% +system cannot keep up with the lip speed + + + align:start position:0% +system cannot keep up with the lip speed +okay + + align:start position:0% +okay + + + align:start position:0% +okay +the amplitude will be very small and + + align:start position:0% +the amplitude will be very small and + + + align:start position:0% +the amplitude will be very small and +also the amplitude will be out of phase + + align:start position:0% +also the amplitude will be out of phase + + + align:start position:0% +also the amplitude will be out of phase +completely okay so that's actually to us + + align:start position:0% +completely okay so that's actually to us + + + align:start position:0% +completely okay so that's actually to us +another demonstration you've seen this + + align:start position:0% +another demonstration you've seen this + + + align:start position:0% +another demonstration you've seen this +little device here this is actually what + + align:start position:0% +little device here this is actually what + + + align:start position:0% +little device here this is actually what +you see before the LeBeau with a Mexican + + align:start position:0% +you see before the LeBeau with a Mexican + + + align:start position:0% +you see before the LeBeau with a Mexican +head okay and you can see that there is + + align:start position:0% +head okay and you can see that there is + + + align:start position:0% +head okay and you can see that there is +a spring attached to this system and on + + align:start position:0% +a spring attached to this system and on + + + align:start position:0% +a spring attached to this system and on +the top what I'm going to do is to use + + align:start position:0% +the top what I'm going to do is to use + + + align:start position:0% +the top what I'm going to do is to use +this motor to drive this system up and + + align:start position:0% +this motor to drive this system up and + + + align:start position:0% +this motor to drive this system up and +down okay where's drag force okay so now + + align:start position:0% +down okay where's drag force okay so now + + + align:start position:0% +down okay where's drag force okay so now +what I'm going to do is to come from a + + align:start position:0% +what I'm going to do is to come from a + + + align:start position:0% +what I'm going to do is to come from a +very low frequency oscillation so you + + align:start position:0% +very low frequency oscillation so you + + + align:start position:0% +very low frequency oscillation so you +can see that the natural frequency is + + align:start position:0% +can see that the natural frequency is + + + align:start position:0% +can see that the natural frequency is +sort of like this + + align:start position:0% +sort of like this + + + align:start position:0% +sort of like this +okay and you can see that okay now i'm + + align:start position:0% +okay and you can see that okay now i'm + + + align:start position:0% +okay and you can see that okay now i'm +tribe in this system really slowly you + + align:start position:0% +tribe in this system really slowly you + + + align:start position:0% +tribe in this system really slowly you +can see this is actually going up and + + align:start position:0% +can see this is actually going up and + + + align:start position:0% +can see this is actually going up and +down reduce slowly okay and you see that + + align:start position:0% +down reduce slowly okay and you see that + + + align:start position:0% +down reduce slowly okay and you see that +huh the amplitude is actually pretty + + align:start position:0% +huh the amplitude is actually pretty + + + align:start position:0% +huh the amplitude is actually pretty +small right there's no excitement for + + align:start position:0% +small right there's no excitement for + + + align:start position:0% +small right there's no excitement for +the moment okay alright so what I'm + + align:start position:0% +the moment okay alright so what I'm + + + align:start position:0% +the moment okay alright so what I'm +going to do is now I increase the speed + + align:start position:0% +going to do is now I increase the speed + + + align:start position:0% +going to do is now I increase the speed +of the motor and see what happened so + + align:start position:0% +of the motor and see what happened so + + + align:start position:0% +of the motor and see what happened so +you can see now this is also essentially + + align:start position:0% +you can see now this is also essentially + + + align:start position:0% +you can see now this is also essentially +driving it with higher and higher + + align:start position:0% +driving it with higher and higher + + + align:start position:0% +driving it with higher and higher +frequency you see that something is + + align:start position:0% +frequency you see that something is + + + align:start position:0% +frequency you see that something is +happening you can see the amplitude is + + align:start position:0% +happening you can see the amplitude is + + + align:start position:0% +happening you can see the amplitude is +getting larger and larger and still + + align:start position:0% +getting larger and larger and still + + + align:start position:0% +getting larger and larger and still +increasing the time the frequency + + align:start position:0% +increasing the time the frequency + + + align:start position:0% +increasing the time the frequency +increasing increasing until something + + align:start position:0% +increasing increasing until something + + + align:start position:0% +increasing increasing until something +something happened right did you see + + align:start position:0% +something happened right did you see + + + align:start position:0% +something happened right did you see +that start to oscillate + + align:start position:0% +that start to oscillate + + + align:start position:0% +that start to oscillate +benda right because right now you can + + align:start position:0% +benda right because right now you can + + + align:start position:0% +benda right because right now you can +see that look at the top okay + + align:start position:0% +see that look at the top okay + + + align:start position:0% +see that look at the top okay +the frequency of the motor is now really + + align:start position:0% +the frequency of the motor is now really + + + align:start position:0% +the frequency of the motor is now really +close to the frequency the natural + + align:start position:0% +close to the frequency the natural + + + align:start position:0% +close to the frequency the natural +frequency of this system okay so so a + + align:start position:0% +frequency of this system okay so so a + + + align:start position:0% +frequency of this system okay so so a +resonance behaviour will happen and what + + align:start position:0% +resonance behaviour will happen and what + + + align:start position:0% +resonance behaviour will happen and what +do you what you are going to get is that + + align:start position:0% +do you what you are going to get is that + + + align:start position:0% +do you what you are going to get is that +okay + + align:start position:0% +okay + + + align:start position:0% +okay +Omega Omega D around Omega zero then you + + align:start position:0% +Omega Omega D around Omega zero then you + + + align:start position:0% +Omega Omega D around Omega zero then you +are going to get large time every two + + align:start position:0% +are going to get large time every two + + + align:start position:0% +are going to get large time every two +okay so now what I'm going to do is to + + align:start position:0% +okay so now what I'm going to do is to + + + align:start position:0% +okay so now what I'm going to do is to +continue to increase the driving + + align:start position:0% +continue to increase the driving + + + align:start position:0% +continue to increase the driving +frequency to a very large value okay now + + align:start position:0% +frequency to a very large value okay now + + + align:start position:0% +frequency to a very large value okay now +it's actually doing the mmm doing this + + align:start position:0% +it's actually doing the mmm doing this + + + align:start position:0% +it's actually doing the mmm doing this +really fast you can see top very fast I + + align:start position:0% +really fast you can see top very fast I + + + align:start position:0% +really fast you can see top very fast I +can even kill even faster you see that + + align:start position:0% +can even kill even faster you see that + + + align:start position:0% +can even kill even faster you see that +ha indeed this system is now oscillating + + align:start position:0% +ha indeed this system is now oscillating + + + align:start position:0% +ha indeed this system is now oscillating +at a larger frequency right is trying to + + align:start position:0% +at a larger frequency right is trying to + + + align:start position:0% +at a larger frequency right is trying to +keep up with the driving force but you + + align:start position:0% +keep up with the driving force but you + + + align:start position:0% +keep up with the driving force but you +can see that the amplitude is actually + + align:start position:0% +can see that the amplitude is actually + + + align:start position:0% +can see that the amplitude is actually +much smaller than what had happened + + align:start position:0% +much smaller than what had happened + + + align:start position:0% +much smaller than what had happened +before so so you before the class you + + align:start position:0% +before so so you before the class you + + + align:start position:0% +before so so you before the class you +may actually think that okay try be + + align:start position:0% +may actually think that okay try be + + + align:start position:0% +may actually think that okay try be +really fast maybe we'll increase the + + align:start position:0% +really fast maybe we'll increase the + + + align:start position:0% +really fast maybe we'll increase the +amplitude but in reality actually you + + align:start position:0% +amplitude but in reality actually you + + + align:start position:0% +amplitude but in reality actually you +will give you a very small amplitude + + align:start position:0% +will give you a very small amplitude + + + align:start position:0% +will give you a very small amplitude +okay another thing which is interesting + + align:start position:0% +okay another thing which is interesting + + + align:start position:0% +okay another thing which is interesting +to know is that you can see that when + + align:start position:0% +to know is that you can see that when + + + align:start position:0% +to know is that you can see that when +the tribe is that when the driving force + + align:start position:0% +the tribe is that when the driving force + + + align:start position:0% +the tribe is that when the driving force +is actually at the Maxima okay and + + align:start position:0% +is actually at the Maxima okay and + + + align:start position:0% +is actually at the Maxima okay and +actually this the position of this mass + + align:start position:0% +actually this the position of this mass + + + align:start position:0% +actually this the position of this mass +is a atom at a minimum right so they are + + align:start position:0% +is a atom at a minimum right so they are + + + align:start position:0% +is a atom at a minimum right so they are +actually out of phase okay I hope you + + align:start position:0% +actually out of phase okay I hope you + + + align:start position:0% +actually out of phase okay I hope you +can see it right beside this okay + + align:start position:0% + + + + align:start position:0% + +okay so what you can see is that when I + + align:start position:0% +okay so what you can see is that when I + + + align:start position:0% +okay so what you can see is that when I +understand this system and I try to + + align:start position:0% +understand this system and I try to + + + align:start position:0% +understand this system and I try to +drive it with the natural frequency what + + align:start position:0% +drive it with the natural frequency what + + + align:start position:0% +drive it with the natural frequency what +is going to happen is that I am exciting + + align:start position:0% +is going to happen is that I am exciting + + + align:start position:0% +is going to happen is that I am exciting +this system to a stay of resonance right + + align:start position:0% +this system to a stay of resonance right + + + align:start position:0% +this system to a stay of resonance right +so basically your case on resonance + + align:start position:0% +so basically your case on resonance + + + align:start position:0% +so basically your case on resonance +behavior so I have shown you that this + + align:start position:0% +behavior so I have shown you that this + + + align:start position:0% +behavior so I have shown you that this +works for driven couple mechanical + + align:start position:0% +works for driven couple mechanical + + + align:start position:0% +works for driven couple mechanical +oscillator he also works for the spring + + align:start position:0% +oscillator he also works for the spring + + + align:start position:0% +oscillator he also works for the spring +mass system right and there are many + + align:start position:0% +mass system right and there are many + + + align:start position:0% +mass system right and there are many +other things which also works which is + + align:start position:0% +other things which also works which is + + + align:start position:0% +other things which also works which is +around you right for example if you + + align:start position:0% +around you right for example if you + + + align:start position:0% +around you right for example if you +happen to be in my office hour okay you + + align:start position:0% +happen to be in my office hour okay you + + + align:start position:0% +happen to be in my office hour okay you +will notice that the air condition in my + + align:start position:0% +will notice that the air condition in my + + + align:start position:0% +will notice that the air condition in my +office is actually creating a resonance + + align:start position:0% +office is actually creating a resonance + + + align:start position:0% +office is actually creating a resonance +behavior you see low frequencies + + align:start position:0% + + + + align:start position:0% + +something is like something like that + + align:start position:0% +something is like something like that + + + align:start position:0% +something is like something like that +and that is because the pipe is actually + + align:start position:0% +and that is because the pipe is actually + + + align:start position:0% +and that is because the pipe is actually +having happened to have the frequency + + align:start position:0% +having happened to have the frequency + + + align:start position:0% +having happened to have the frequency +match with the resonance frequency okay + + align:start position:0% +match with the resonance frequency okay + + + align:start position:0% +match with the resonance frequency okay +the airflow issue happened to excite the + + align:start position:0% +the airflow issue happened to excite the + + + align:start position:0% +the airflow issue happened to excite the +the pipe so that is we essentially other + + align:start position:0% +the pipe so that is we essentially other + + + align:start position:0% +the pipe so that is we essentially other +than yumping dam at a frequency so what + + align:start position:0% +than yumping dam at a frequency so what + + + align:start position:0% +than yumping dam at a frequency so what +I did was I try to turn it down to low + + align:start position:0% +I did was I try to turn it down to low + + + align:start position:0% +I did was I try to turn it down to low +and see what happened but unfortunately + + align:start position:0% +and see what happened but unfortunately + + + align:start position:0% +and see what happened but unfortunately +yes you excite another resonance okay I + + align:start position:0% +yes you excite another resonance okay I + + + align:start position:0% +yes you excite another resonance okay I +see now another low frequency sound but + + align:start position:0% +see now another low frequency sound but + + + align:start position:0% +see now another low frequency sound but +a very high frequency sound I will post + + align:start position:0% +a very high frequency sound I will post + + + align:start position:0% +a very high frequency sound I will post +a video it should be online so my life + + align:start position:0% +a video it should be online so my life + + + align:start position:0% +a video it should be online so my life +is hard right so but I mean I never + + align:start position:0% +is hard right so but I mean I never + + + align:start position:0% +is hard right so but I mean I never +physicist so I choose to use the median + + align:start position:0% +physicist so I choose to use the median + + + align:start position:0% +physicist so I choose to use the median +then I actually stay between the two + + align:start position:0% +then I actually stay between the two + + + align:start position:0% +then I actually stay between the two +resonance then I don't see like the + + align:start position:0% +resonance then I don't see like the + + + align:start position:0% +resonance then I don't see like the +night on here the additional song which + + align:start position:0% +night on here the additional song which + + + align:start position:0% +night on here the additional song which +passes me okay another example is that + + align:start position:0% +passes me okay another example is that + + + align:start position:0% +passes me okay another example is that +when I was in Taiwan as an undergrad I + + align:start position:0% +when I was in Taiwan as an undergrad I + + + align:start position:0% +when I was in Taiwan as an undergrad I +was living outside you know apartment + + align:start position:0% +was living outside you know apartment + + + align:start position:0% +was living outside you know apartment +and with my fret mate we owned a very + + align:start position:0% +and with my fret mate we owned a very + + + align:start position:0% +and with my fret mate we owned a very +old washing machine ok so in the middle + + align:start position:0% +old washing machine ok so in the middle + + + align:start position:0% +old washing machine ok so in the middle +of night the washing machine will start + + align:start position:0% +of night the washing machine will start + + + align:start position:0% +of night the washing machine will start +to walk around like my frat may okay and + + align:start position:0% +to walk around like my frat may okay and + + + align:start position:0% +to walk around like my frat may okay and +we were not scared because that is + + align:start position:0% +we were not scared because that is + + + align:start position:0% +we were not scared because that is +because the oscillation frequency + + align:start position:0% +because the oscillation frequency + + + align:start position:0% +because the oscillation frequency +actually the rotation it should happen + + align:start position:0% +actually the rotation it should happen + + + align:start position:0% +actually the rotation it should happen +to match with the frequency of the + + align:start position:0% +to match with the frequency of the + + + align:start position:0% +to match with the frequency of the +washing machine therefore when we start + + align:start position:0% +washing machine therefore when we start + + + align:start position:0% +washing machine therefore when we start +to wash our clothes they start to walk + + align:start position:0% +to wash our clothes they start to walk + + + align:start position:0% +to wash our clothes they start to walk +around in the room so as a physicist + + align:start position:0% +around in the room so as a physicist + + + align:start position:0% +around in the room so as a physicist +what we have decided is to make the spin + + align:start position:0% +what we have decided is to make the spin + + + align:start position:0% +what we have decided is to make the spin +slightly slower then as you can see that + + align:start position:0% +slightly slower then as you can see that + + + align:start position:0% +slightly slower then as you can see that +or even faster then issue you can see + + align:start position:0% +or even faster then issue you can see + + + align:start position:0% +or even faster then issue you can see +that when you do that then you get rid + + align:start position:0% +that when you do that then you get rid + + + align:start position:0% +that when you do that then you get rid +of the Restless behavior so it's not + + align:start position:0% +of the Restless behavior so it's not + + + align:start position:0% +of the Restless behavior so it's not +working around anymore + + align:start position:0% +working around anymore + + + align:start position:0% +working around anymore +we can control it okay another thing + + align:start position:0% +we can control it okay another thing + + + align:start position:0% +we can control it okay another thing +which is interesting is that the + + align:start position:0% +which is interesting is that the + + + align:start position:0% +which is interesting is that the +resonance behavior is not only in the + + align:start position:0% +resonance behavior is not only in the + + + align:start position:0% +resonance behavior is not only in the +physical object which we actually deal + + align:start position:0% +physical object which we actually deal + + + align:start position:0% +physical object which we actually deal +with these days also but after you learn + + align:start position:0% +with these days also but after you learn + + + align:start position:0% +with these days also but after you learn +quantum + + align:start position:0% +quantum + + + align:start position:0% +quantum +quantum field theory you'll find that + + align:start position:0% +quantum field theory you'll find that + + + align:start position:0% +quantum field theory you'll find that +there are resonance also in mass a wave + + align:start position:0% +there are resonance also in mass a wave + + + align:start position:0% +there are resonance also in mass a wave +function okay so basically you can see + + align:start position:0% +function okay so basically you can see + + + align:start position:0% +function okay so basically you can see +that these are example of the Z boson + + align:start position:0% +that these are example of the Z boson + + + align:start position:0% +that these are example of the Z boson +resonance peak so if you scatter in + + align:start position:0% +resonance peak so if you scatter in + + + align:start position:0% +resonance peak so if you scatter in +electron and positron then basically you + + align:start position:0% +electron and positron then basically you + + + align:start position:0% +electron and positron then basically you +see that the cross section have + + align:start position:0% +see that the cross section have + + + align:start position:0% +see that the cross section have +resonance peak at around 90 GeV okay and + + align:start position:0% +resonance peak at around 90 GeV okay and + + + align:start position:0% +resonance peak at around 90 GeV okay and +that is actually another very + + align:start position:0% +that is actually another very + + + align:start position:0% +that is actually another very +interesting example about resonance in + + align:start position:0% +interesting example about resonance in + + + align:start position:0% +interesting example about resonance in +particle physics finally the last + + align:start position:0% +particle physics finally the last + + + align:start position:0% +particle physics finally the last +example which I am going to go through + + align:start position:0% +example which I am going to go through + + + align:start position:0% +example which I am going to go through +is a example involving a glass okay we + + align:start position:0% +is a example involving a glass okay we + + + align:start position:0% +is a example involving a glass okay we +have prepared a very high-quality glass + + align:start position:0% +have prepared a very high-quality glass + + + align:start position:0% +have prepared a very high-quality glass +here okay maybe you have seen this class + + align:start position:0% +here okay maybe you have seen this class + + + align:start position:0% +here okay maybe you have seen this class +before they are very nice and I usually + + align:start position:0% +before they are very nice and I usually + + + align:start position:0% +before they are very nice and I usually +use it to enjoy my red wines which you + + align:start position:0% +use it to enjoy my red wines which you + + + align:start position:0% +use it to enjoy my red wines which you +can I enjoy pop it now so you can see + + align:start position:0% +can I enjoy pop it now so you can see + + + align:start position:0% +can I enjoy pop it now so you can see +that if this is the glass and if I put a + + align:start position:0% +that if this is the glass and if I put a + + + align:start position:0% +that if this is the glass and if I put a +little water on my hand and I rub it + + align:start position:0% + + + + align:start position:0% + +carefully I can actually excite one of + + align:start position:0% +carefully I can actually excite one of + + + align:start position:0% +carefully I can actually excite one of +the resonance frequency okay so so you + + align:start position:0% +the resonance frequency okay so so you + + + align:start position:0% +the resonance frequency okay so so you +can see that we have always been working + + align:start position:0% +can see that we have always been working + + + align:start position:0% +can see that we have always been working +on a single particle okay and that will + + align:start position:0% +on a single particle okay and that will + + + align:start position:0% +on a single particle okay and that will +give you one resonance frequency if I + + align:start position:0% +give you one resonance frequency if I + + + align:start position:0% +give you one resonance frequency if I +work on two particles which we will see + + align:start position:0% +work on two particles which we will see + + + align:start position:0% +work on two particles which we will see +that in the next lecture I were to get + + align:start position:0% +that in the next lecture I were to get + + + align:start position:0% +that in the next lecture I were to get +two resonance frequency and this glass + + align:start position:0% +two resonance frequency and this glass + + + align:start position:0% +two resonance frequency and this glass +is made of infinite number of particles + + align:start position:0% +is made of infinite number of particles + + + align:start position:0% +is made of infinite number of particles +therefore I will have infinite number of + + align:start position:0% +therefore I will have infinite number of + + + align:start position:0% +therefore I will have infinite number of +resonance frequency okay when I am + + align:start position:0% +resonance frequency okay when I am + + + align:start position:0% +resonance frequency okay when I am +rubbing it + + align:start position:0% +rubbing it + + + align:start position:0% +rubbing it +I'm actually giving input of all kinds + + align:start position:0% +I'm actually giving input of all kinds + + + align:start position:0% +I'm actually giving input of all kinds +of different frequencies but the the + + align:start position:0% +of different frequencies but the the + + + align:start position:0% +of different frequencies but the the +class will be smart enough so that you + + align:start position:0% +class will be smart enough so that you + + + align:start position:0% +class will be smart enough so that you +will pick up the one he likes the most + + align:start position:0% +will pick up the one he likes the most + + + align:start position:0% +will pick up the one he likes the most +which is the resonance frequency so you + + align:start position:0% +which is the resonance frequency so you + + + align:start position:0% +which is the resonance frequency so you +can see that the sound he says should be + + align:start position:0% +can see that the sound he says should be + + + align:start position:0% +can see that the sound he says should be +roughly 683 hurt okay and you can + + align:start position:0% +roughly 683 hurt okay and you can + + + align:start position:0% +roughly 683 hurt okay and you can +actually measure it with your phone + + align:start position:0% +actually measure it with your phone + + + align:start position:0% +actually measure it with your phone +right okay so on the TV commercial you + + align:start position:0% +right okay so on the TV commercial you + + + align:start position:0% +right okay so on the TV commercial you +may have seen that there's a lady + + align:start position:0% +may have seen that there's a lady + + + align:start position:0% +may have seen that there's a lady +singing you know he seemed so louder D + + align:start position:0% +singing you know he seemed so louder D + + + align:start position:0% +singing you know he seemed so louder D +such that the glass breaks right can we + + align:start position:0% +such that the glass breaks right can we + + + align:start position:0% +such that the glass breaks right can we +get that volunteer today to sing in + + align:start position:0% +get that volunteer today to sing in + + + align:start position:0% +get that volunteer today to sing in +front of oh I see can you sing it high + + align:start position:0% +front of oh I see can you sing it high + + + align:start position:0% +front of oh I see can you sing it high +high frequencies + + align:start position:0% + + + + align:start position:0% + +very good try but didn't work okay okay + + align:start position:0% +very good try but didn't work okay okay + + + align:start position:0% +very good try but didn't work okay okay +I think I guess it's really difficult to + + align:start position:0% +I think I guess it's really difficult to + + + align:start position:0% +I think I guess it's really difficult to +perform that in front of so many people + + align:start position:0% +perform that in front of so many people + + + align:start position:0% +perform that in front of so many people +unprepared but fortunately we are an IT + + align:start position:0% +unprepared but fortunately we are an IT + + + align:start position:0% +unprepared but fortunately we are an IT +so we have designed that is a device + + align:start position:0% +so we have designed that is a device + + + align:start position:0% +so we have designed that is a device +which actually can help us to achieve + + align:start position:0% +which actually can help us to achieve + + + align:start position:0% +which actually can help us to achieve +this okay so this device is actually + + align:start position:0% +this okay so this device is actually + + + align:start position:0% +this okay so this device is actually +content amplifier here and I can now + + align:start position:0% +content amplifier here and I can now + + + align:start position:0% +content amplifier here and I can now +control the frequency of the sound + + align:start position:0% +control the frequency of the sound + + + align:start position:0% +control the frequency of the sound +through this scope and this amplifier + + align:start position:0% +through this scope and this amplifier + + + align:start position:0% +through this scope and this amplifier +will actually amplify the signal and the + + align:start position:0% +will actually amplify the signal and the + + + align:start position:0% +will actually amplify the signal and the +producer Soundwave and try to actually + + align:start position:0% +producer Soundwave and try to actually + + + align:start position:0% +producer Soundwave and try to actually +oscillate this class okay so we are + + align:start position:0% +oscillate this class okay so we are + + + align:start position:0% +oscillate this class okay so we are +going to do this experiment so we will + + align:start position:0% +going to do this experiment so we will + + + align:start position:0% +going to do this experiment so we will +need to change the light set in a bit + + align:start position:0% +need to change the light set in a bit + + + align:start position:0% +need to change the light set in a bit +because the Sun is going to be probably + + align:start position:0% +because the Sun is going to be probably + + + align:start position:0% +because the Sun is going to be probably +too loud just for safety some of you may + + align:start position:0% +too loud just for safety some of you may + + + align:start position:0% +too loud just for safety some of you may +not survive + + align:start position:0% +not survive + + + align:start position:0% +not survive +so I'm handing out this okay who is + + align:start position:0% +so I'm handing out this okay who is + + + align:start position:0% +so I'm handing out this okay who is +closer okay + + align:start position:0% +closer okay + + + align:start position:0% +closer okay +oh oh sorry I'm so sorry + + align:start position:0% +oh oh sorry I'm so sorry + + + align:start position:0% +oh oh sorry I'm so sorry +what I don't need that okay so so just + + align:start position:0% +what I don't need that okay so so just + + + align:start position:0% +what I don't need that okay so so just +for safety I will put this on and what + + align:start position:0% +for safety I will put this on and what + + + align:start position:0% +for safety I will put this on and what +I'm going to do is also put this curse + + align:start position:0% +I'm going to do is also put this curse + + + align:start position:0% +I'm going to do is also put this curse +on right okay to this first + + align:start position:0% + + + + align:start position:0% + +okay so what I'm going to do now is to + + align:start position:0% +okay so what I'm going to do now is to + + + align:start position:0% +okay so what I'm going to do now is to +start producing Soundwave so through the + + align:start position:0% +start producing Soundwave so through the + + + align:start position:0% +start producing Soundwave so through the +camera you should be able to see what + + align:start position:0% +camera you should be able to see what + + + align:start position:0% +camera you should be able to see what +this issue is showing in on the spring + + align:start position:0% +this issue is showing in on the spring + + + align:start position:0% +this issue is showing in on the spring +so you can see this you can even see + + align:start position:0% +so you can see this you can even see + + + align:start position:0% +so you can see this you can even see +that if if this class is actually moving + + align:start position:0% +that if if this class is actually moving + + + align:start position:0% +that if if this class is actually moving +the wood inside will also vibrate okay + + align:start position:0% +the wood inside will also vibrate okay + + + align:start position:0% +the wood inside will also vibrate okay +so you can see that clearly we don't + + align:start position:0% +so you can see that clearly we don't + + + align:start position:0% +so you can see that clearly we don't +have rest on us yet so what I am going + + align:start position:0% +have rest on us yet so what I am going + + + align:start position:0% +have rest on us yet so what I am going +to do is to increase the frequency and + + align:start position:0% +to do is to increase the frequency and + + + align:start position:0% +to do is to increase the frequency and +see what happens so now it's so now it's + + align:start position:0% +see what happens so now it's so now it's + + + align:start position:0% +see what happens so now it's so now it's +actually the 643 say she's Filipino the + + align:start position:0% +actually the 643 say she's Filipino the + + + align:start position:0% +actually the 643 say she's Filipino the +resonance frequency now I have measure + + align:start position:0% +resonance frequency now I have measure + + + align:start position:0% +resonance frequency now I have measure +the frequency should be 684 so now it's + + align:start position:0% +the frequency should be 684 so now it's + + + align:start position:0% +the frequency should be 684 so now it's +a c6 53 + + align:start position:0% + + + + align:start position:0% + +6:63 hurt + + align:start position:0% + + + + align:start position:0% + +673 Hertz can you see the movement you + + align:start position:0% +673 Hertz can you see the movement you + + + align:start position:0% +673 Hertz can you see the movement you +cannot see the movement still yet + + align:start position:0% + + + + align:start position:0% + +683 you see you see now the frequency of + + align:start position:0% +683 you see you see now the frequency of + + + align:start position:0% +683 you see you see now the frequency of +the sound is actually matching with the + + align:start position:0% +the sound is actually matching with the + + + align:start position:0% +the sound is actually matching with the +nature of one of the natural frequency + + align:start position:0% +nature of one of the natural frequency + + + align:start position:0% +nature of one of the natural frequency +of the class ok apparently the class + + align:start position:0% +of the class ok apparently the class + + + align:start position:0% +of the class ok apparently the class +like it ok and now you can see that we + + align:start position:0% +like it ok and now you can see that we + + + align:start position:0% +like it ok and now you can see that we +still start vibrating and the next step + + align:start position:0% +still start vibrating and the next step + + + align:start position:0% +still start vibrating and the next step +which we are going to do is to try to + + align:start position:0% +which we are going to do is to try to + + + align:start position:0% +which we are going to do is to try to +increase the amplitude increase the + + align:start position:0% +increase the amplitude increase the + + + align:start position:0% +increase the amplitude increase the +volume of the sound and see what + + align:start position:0% +volume of the sound and see what + + + align:start position:0% +volume of the sound and see what +happened maybe you want to cover you a + + align:start position:0% +happened maybe you want to cover you a + + + align:start position:0% +happened maybe you want to cover you a +year just for safety + + align:start position:0% +year just for safety + + + align:start position:0% +year just for safety +okay then the then the the glass may + + align:start position:0% +okay then the then the the glass may + + + align:start position:0% +okay then the then the the glass may +break if we are lucky okay should I see + + align:start position:0% +break if we are lucky okay should I see + + + align:start position:0% +break if we are lucky okay should I see +what is going to happen + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +yeah thank you very much thank you gasps + + align:start position:0% + + + + align:start position:0% + +so you can see the power of resonance + + align:start position:0% +so you can see the power of resonance + + + align:start position:0% +so you can see the power of resonance +right so if I tune down the frequency + + align:start position:0% +right so if I tune down the frequency + + + align:start position:0% +right so if I tune down the frequency +slightly more then it will be where + + align:start position:0% +slightly more then it will be where + + + align:start position:0% +slightly more then it will be where +you'll be here right then you will not + + align:start position:0% +you'll be here right then you will not + + + align:start position:0% +you'll be here right then you will not +have enough amplitude to break the glass + + align:start position:0% +have enough amplitude to break the glass + + + align:start position:0% +have enough amplitude to break the glass +and also the clip we discussed before + + align:start position:0% +and also the clip we discussed before + + + align:start position:0% +and also the clip we discussed before +the quality of the glass should be + + align:start position:0% +the quality of the glass should be + + + align:start position:0% +the quality of the glass should be +really really high such that the + + align:start position:0% +really really high such that the + + + align:start position:0% +really really high such that the +resulting amplitude will be very large + + align:start position:0% +resulting amplitude will be very large + + + align:start position:0% +resulting amplitude will be very large +then you can actually break it with + + align:start position:0% +then you can actually break it with + + + align:start position:0% +then you can actually break it with +external song wave and if we go above + + align:start position:0% +external song wave and if we go above + + + align:start position:0% +external song wave and if we go above +the resonance frequency then you will + + align:start position:0% +the resonance frequency then you will + + + align:start position:0% +the resonance frequency then you will +not also move a bit because you know + + align:start position:0% +not also move a bit because you know + + + align:start position:0% +not also move a bit because you know +because if you go to very large Omega D + + align:start position:0% +because if you go to very large Omega D + + + align:start position:0% +because if you go to very large Omega D +then every two will be pretty small okay + + align:start position:0% +then every two will be pretty small okay + + + align:start position:0% +then every two will be pretty small okay +let me try to switch back to my + + align:start position:0% +let me try to switch back to my + + + align:start position:0% +let me try to switch back to my +presentation + + align:start position:0% + + + + align:start position:0% + +okay so this is as you what we have + + align:start position:0% +okay so this is as you what we have + + + align:start position:0% +okay so this is as you what we have +learned today we have learned that + + align:start position:0% +learned today we have learned that + + + align:start position:0% +learned today we have learned that +behavior of attempted ribbon oscillator + + align:start position:0% +behavior of attempted ribbon oscillator + + + align:start position:0% +behavior of attempted ribbon oscillator +okay we have learned the transom + + align:start position:0% +okay we have learned the transom + + + align:start position:0% +okay we have learned the transom +transient behavior so what is actually + + align:start position:0% +transient behavior so what is actually + + + align:start position:0% +transient behavior so what is actually +transient behavior is actually a mixture + + align:start position:0% +transient behavior is actually a mixture + + + align:start position:0% +transient behavior is actually a mixture +or it's a mixture of steady-state + + align:start position:0% +or it's a mixture of steady-state + + + align:start position:0% +or it's a mixture of steady-state +solution which is coming from the tribe + + align:start position:0% +solution which is coming from the tribe + + + align:start position:0% +solution which is coming from the tribe +in force and the homogeneous solution + + align:start position:0% +in force and the homogeneous solution + + + align:start position:0% +in force and the homogeneous solution +okay if you wait long enough this will + + align:start position:0% +okay if you wait long enough this will + + + align:start position:0% +okay if you wait long enough this will +decay and the disappear okay and we have + + align:start position:0% +decay and the disappear okay and we have + + + align:start position:0% +decay and the disappear okay and we have +learned resonance right so in IOC + + align:start position:0% +learned resonance right so in IOC + + + align:start position:0% +learned resonance right so in IOC +circuit which you actually solved that + + align:start position:0% +circuit which you actually solved that + + + align:start position:0% +circuit which you actually solved that +in your pset in pendulum which way I + + align:start position:0% +in your pset in pendulum which way I + + + align:start position:0% +in your pset in pendulum which way I +just show you which helped me my son to + + align:start position:0% +just show you which helped me my son to + + + align:start position:0% +just show you which helped me my son to +learn waves and vibrations and a + + align:start position:0% +learn waves and vibrations and a + + + align:start position:0% +learn waves and vibrations and a +condition washing machine class particle + + align:start position:0% +condition washing machine class particle + + + align:start position:0% +condition washing machine class particle +physics we can see templars driven + + align:start position:0% +physics we can see templars driven + + + align:start position:0% +physics we can see templars driven +oscillator or resonance almost + + align:start position:0% +oscillator or resonance almost + + + align:start position:0% +oscillator or resonance almost +everywhere okay so I hope that you enjoy + + align:start position:0% +everywhere okay so I hope that you enjoy + + + align:start position:0% +everywhere okay so I hope that you enjoy +the lecture today and what we are going + + align:start position:0% +the lecture today and what we are going + + + align:start position:0% +the lecture today and what we are going +to do next time is to put multiple + + align:start position:0% +to do next time is to put multiple + + + align:start position:0% +to do next time is to put multiple +object together so that you will see the + + align:start position:0% +object together so that you will see the + + + align:start position:0% +object together so that you will see the +interaction between one particle to the + + align:start position:0% +interaction between one particle to the + + + align:start position:0% +interaction between one particle to the +other particle and see how we can + + align:start position:0% +other particle and see how we can + + + align:start position:0% +other particle and see how we can +actually make sense of this kind of + + align:start position:0% +actually make sense of this kind of + + + align:start position:0% +actually make sense of this kind of +system thank you very much + + align:start position:0% +system thank you very much + + + align:start position:0% +system thank you very much +and when I will be here if you have + + align:start position:0% +and when I will be here if you have + + + align:start position:0% +and when I will be here if you have +additional questions to relate it to a + + align:start position:0% +additional questions to relate it to a + + + align:start position:0% +additional questions to relate it to a +lecture + + align:start position:0% + + + + align:start position:0% + +you \ No newline at end of file diff --git a/Fixc8hVo_cY.txt b/Fixc8hVo_cY.txt new file mode 100644 index 0000000000000000000000000000000000000000..ef0b5a732f52fad45d8dceca8045ec0e085a2c5f --- /dev/null +++ b/Fixc8hVo_cY.txt @@ -0,0 +1,2106 @@ +The following content is +provided under a Creative + +Commons license. + +Your support will help MIT +OpenCourseWare continue to + +offer high quality educational +resources for free. + +To make a donation or view +additional materials from + +hundreds of MIT courses, visit +MIT OpenCourseWare at + +ocw.mit.edu. + +PROFESSOR: So let's start. + +I mean for the first question +you can answer what is tuple. + +You can go to that later. + +Can a tuple contain a list? + +What do you think? + +Can a tuple contain a list? + +AUDIENCE: Yes. + +PROFESSOR: Yes, it can. + +So we'll go through the +examples later. + +And let's see this +first example. + +We have two tuples. + +The tuple B contains tuple +A, as well as a list. + +So it can't populate. + +Let's bring those lists, too. + +So for the first example we try +to access the elements 0 + +and 2 of the tuple A. And +let me use minus 1 to + +access which element? + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: OK. + +And 0 is the first element, +of course. + +And remember now we +are using 0, 1. + +OK, what is tuple B? + +It's a two-dimensional tuple. + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: Yeah, exactly. + +It has a list and +a tuple inside. + +So the first element is +a tuple, and the last + +element is the list. + +So now it's sort of like +two-dimensional. + +But if you look at the first +element of it, the MIT word, + +that doesn't have +any dimension. + +Does it? + +It's a string. + +So you can again access, +but not this way. + +But still you can access. + +And we are using this notation +to access a portion of the + +list, a part of the tuple, +actually, here. + +It's called slicing. + +So here 0 to 1 gives +you which element? + +Just one element right? + +It's the first element. + +0 to 2 gives you 1 and 2 OK? + +This is an interesting +usage of the slicing. + +This is used to access +the whole tuple. + +Now you might wonder +why we need them. + +We could just-- + +the handouts are here. + +So why we need to copy or why +we need to access the list + +through the column operator +like this? + +We'll look at that later. + +It's very essential when +we have lists. + +For the timing it's OK when +tuples are immutable. + +So it doesn't have +a special usage. + +But later on we'll +be using it. + +Then if you look at this +part, this is the + +most interesting part. + +How do iterate through +a tuple? + +You use a FOR loop and you call +like item in tuple, the + +element in tuple. + +The element is initialized with +every element when it + +goes through iteration. + +At every iteration it will +be instantiated with the + +corresponding element +in the tuple. + +But you're using the +same name anyway. + +It's item. + +This is equivalent to accessing +the tuple like this. + +Going one-by-one in the range +and accessing their + +corresponding element +in the tuple. + +So this is the simpler +way to access that. + +Do you have any questions +in that part? + +Yeah? + +AUDIENCE: For that part, don't, +usually if you have a + +range you have to [INAUDIBLE] + +name because is not-- + +PROFESSOR: OK, that's correct. + +. + +OK. + +Suppose a tuple has 3 elements, +or for example in + +this case tuple A, how many +elements are in the tuple A? + +3 elements. + +So what would be the +length of tuple A? + +AUDIENCE: 3. + +PROFESSOR: 3. + +But what would be the range? + +0, 1, 2, right? + +So you have to type 0 to 3. + +So that's why I put that, OK? + +That is 3, OK? + +PROFESSOR: You. + +AUDIENCE: So you just say a +range like the tuple is, it + +seems like the first one-- + +PROFESSOR: First the 0 if you +don't specify it the same way. + +OK. + +Now let's go through the list. + +So if you go through the +questions, what is the + +difference between a +list and a tuple? + +What is the difference between +a list and a tuple? + +Anyone? + +Yeah? + +AUDIENCE: Tuples +are immutable. + +PROFESSOR: OK. + +Lists are mutable. + +And because it's mutable it +takes special functions to + +access the elements, +add elements, and + +modify the list itself. + +How would you add an +element to a list? + +Suppose you have list A. How +would you add 3 to this list? + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: OK. + +Let's start our print. + +OK. + +That's good. + +OK? + +How would you remove +the element from + +the top of the list? + +Or the last element, how +would you remove + +this 3 from the list? + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: This one? + +Let's see. + +You know how to check +the specification + +of a function, right? + +Sorry. + +So it's not the right +function, right? + +Because it says it removes +the first occurrence of a + +particular value you are parsing +to that function. + +OK, there's another function. + +It's called list.pop. + +That removes the last inserted +value, so it + +pops from the top. + +So remove can be used to remove +a particular element. + +So here suppose we +want to remove 1. + +So we could say list +A, remove 1. + +OK. + +So in this example, +actually, I have + +commented out this line. + +This will be an error +if I execute. + +Why? + +Why will it give you an error? + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: It doesn't exit. + +Great. + +So the problem here is we can't +access an element in the + +list unless we explicitly +assign + +something or create something. + +But suppose we want to pass +a list of 10 elements to a + +program so that it can assign +values on the fly. + +And it can modify. + +OK? + +So how would you pass an empty +list of 10 elements? + +OK. + +The problem is if you're passing +something like this, + +you need to know how this list +should be instantiated. + +So you should know what +are the initial + +values of these elements. + +Suppose you want to create +a list of ten 0's. + +Then the easiest way to +create the list is-- + +So you would create a list +with ten elements. + +But If you don't want to waste +memory, or if you don't want + +to keep anything particular, +you could do + +something like this. + +Now this will create a +list of empty list. + +And there'll be ten +such empty lists. + +OK? + +And you could pass this list to +a program so that it will + +assign the elements. + +OK? + +You can iterate to the +list the same way. + +But lists are interesting. + +Why? + +They are mutable. + +So they can be actually used +to create interesting + +mathematical objects. + +For example, like matrix. + +So how would you create +a matrix using lists? + +Any ideas? + +How would you create, +say a 2 by 2 matrix? + +If you consider this example, +this creates a matrix 4 by 2. + +So that would be like 4 +rows and 2 columns. + +But how can you go and +access the inner + +element or inner matrix? + +So if you suppose you want +access 2, 3, that is the third + +row, then how would +you access? + +How would you call M? + +AUDIENCE: M3? + +PROFESSOR: M3. + +M3 gives you 2, 3. + +Suppose you want to access +the 3 and the 2, 3. + +Then we-- + +[INTERPOSING VOICES] + +PROFESSOR: Sorry. + +AUDIENCE: Why does a 3 +give you [INAUDIBLE]? + +PROFESSOR: Oh, sorry. + +My bad. + +Yeah. + +OK. + +This is computer science, +not maths. + +You got it right, why +it's not 3, it's 2? + +AUDIENCE: Yeah. + +I thought you were talking +about 3 and 4. + +PROFESSOR: OK. + +That's fine. + +So I'm asking now how +would you access the + +3 in the 2, 3 box? + +AUDIENCE: So I need to do +another parentheses? + +PROFESSOR: Not a bracket. + +AUDIENCE: OK. + +PROFESSOR: OK. + +That is all. + +So you can access matrices +like this. + +OK. + +Great. + +We are on time. + +So this actually gives you +a summary of functions. + +Associated functions. + +For example the pop I +explained earlier. + +Remove removes a particular +element. + +Extent, that's interesting. + +Can you tell me what +it does here, the + +method extent on list? + +What does that method take? + +It takes another list. + +So which means it's going to +merge the list you are passing + +with the list you're calling +the method on, that is + +[UNINTELLIGIBLE]. + +So it's going to combine +those lists. + +Let's see. + +So this corresponds to this. + +So two lists are combined. + +So this method is actually +useful, right, because you + +don't have to write yourself. + +Most of things you +can easily do. + +Now the question is, why tuple +didn't have these methods? + +Why? + +Why we didn't have these +methods for tuples? + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: They're immutable. + +So you can't extent, you +can't [UNINTELLIGIBLE]. + +So even if you extent, +what would happen? + +It's going to create +a new tuple. + +Actually, you can do that. + +But like this. + +For example, you have tuple +A which is 1, 2. + +And suppose you have +tuple B -- + +3, 4. + +If you want to combine them, +how would you do it? + +Tuple A plus tuple B. OK? + +That concatenates. + +This operator is all +loaded for tuples. + +OK? + +So lists are mutable so you can +do all of these things. + +Let's look at a few other +examples, too. + +OK. + +There's an interesting +part here. + +Lists are mutable. + +That we understand. + +But how these lists are actually +stored in the memory, + +For example, suppose you +have a list lst, + +sorry, 0, 1, apple. + +How do you think it's stored +in the memory? + +So you have 3 elements. + +But these elements are actually +not stored in the + +list itself. + +They actually in the memory. + +0, 1, apple. + +But you have the pointers +to those lists. + +Sorry, to those elements. + +So actually you can modify these +values without changing + +the list itself, because the +list actually points to this + +part, the container. + +So in this example you have list +A and B. But the list B + +actually contains list A. OK? + +Since list A is mutable you +can go and change it. + +So here first you print list A +and B, but you're going to + +change list A's 0th element. + +After changing the element +the list A becomes first. + +Its first element +changed to 88. + +OK. + +Fine. + +What do you think the +list B would be? + +OK, let's print. + +It contains the 88, right, +the modified value. + +Why? + +Because list B actually had a +pointer to list A. Which again + +had pointers to other +elements. + +And we modified this +value to 88. + +So you're still accessing +list B. OK? + +The pointers are not changed. + +That we can see here, in +the second example, + +the problem of aliasing. + +So we have list X. And we call +it by list Y as well. + +And we are now changing +the list Y. Sorry. + +We are changing the list X. But +it's going to affect list + +X as well as list Y. See? + +Because it's just a reference. + +The actual object is this. + +You can call it by two +different names. + +It doesn't matter. + +But the actual object is here. + +That's where we need +this operator. + +So if you just point, OK, for +example we had list X, if you + +just assign list Y to list X, +it's not going to copy the + +elements, just going to +copy the reference. + +Which means list X and list Y, +both would be pointing to the + +same object. + +If you want to copy these +elements and put in a new one, + +say, list Z, then we need to +copy one-by-one every element. + +For that we can use +this operator. + +It's called full slicing. + +It's not going to +modify elements. + +It's going to copy the whole +list of elements. + +And in the same line, just +another small example that + +tells you how to cast a +list into tuple, and + +a tuple into list. + +So you had a tuple, one for +apple [UNINTELLIGIBLE] + +and you cast into list. + +Now the type is list. + +It's a very simple operation. + +Can you do that yourself? + +How would you do it if you want +to write a function to + +cast, how would you do that? + +You go through element by +element and add it to a tuple. + +And then concatentae +two tuples. + +Right? + +So I guess you can write +probably as a + +homework, try that. + +Try how to convert a list to +a tuple without explicitly + +calling the casting function. + +OK. + +Similarly you can convert +a tuple back into list. + +So it's pretty straightforward. + +And suppose you're getting +an input from + +the user as a tuple. + +then suppose you want +to make it a list. + +You don't have to write +your function. + +You can just call this +casting operator. + +So it'll be-- + +it will save some time. + +OK. + +Great. + +Let's go to our dictionaries +now. + +So we have a third data +type, dictionaries. + +Oh, you didn't get +the second one? + +So we have another data +type, dictionaries. + +And why do we need dictionaries + +in the first place? + +Do we need another data type? + +Can we just get away with +tuple and list? + +Yes. + +Because you can actually make +a dictionary out of lists. + +And Professor Grimson went +through that in the lecture. + +If you want, you can come and +ask in the office hours. + +But first try whether you +can do it yourself. + +But the problem is, actually not +just the dictionaries, but + +the high-level data structures +are actually available in + +Python as building data +structures or as classes. + +Just because they will have +these methods on these data + +structures implemented. + +So it would say some +time for us. + +Plus those methods are +guaranteed to be state of art. + +For example, if you want to go +through all the lists, then + +the search function or the +lookup function that you write + +may not be that efficient, +right? + +But they might use those +efficient algorithms in the + +standard implementation. + +So it's why you should +always look for the + +standard data types. + +If you can't you can +write yourself one. + +But it's good to use the +available data types so that + +they would have this efficient +method implemented. + +OK. + +So in this dictionary, +we have two elements. + +One is key, one is value. + +OK? + +So these keys actually have +a special property. + +What is that? + +The keys should be an +immutable object. + +So you can actually have +a tuple as a key. + +You can have a string as a key, +but not a list as a key. + +So you need an immutable +object for the keys. + +What about the values? + +They can be anything. + +Values can be even +a dictionary. + +It can be a list. + +But the keys must be mutable. + +Do these keys need +to be unique? + +Yes. + +No? + +OK. + +The problem is this. + +Dictionaries have the same +type, I mean structure. + +This is a key. + +And this key points to a +place in the memory. + +Suppose you call it key A. OK? + +If you assign another value to +key A, that will actually + +replace the content in +the memory, right? + +So that's why keys are going +to be unique, It's by + +construction, by the +construction of the dictionary + +the keys are going +to be unique. + +Because if you want to assign +something different, you have + +to call it by a different key, +call it by a different name. + +Say key B. + +What about the values. + +Do they need to be unique? + +No, of course. + +Otherwise no use of key, and no +use of dictionaries, right? + +What is the order of the items +stored in the dictionary? + +Can you give a guarantee +like in lists? + +In lists items are stored from +zero to the left, right? + +Length minus 1, actually. + +What about dictionaries? + +Surely can't guarantee +the order, but you + +can modify the order. + +OK. + +So the thing is first, if you +look at this example, first we + +have the staff dictionary. + +And when I pin the length +it gives me 3, fine. + +Then I'm doing three things. + +First I change the address +by calling its key. + +And dictionaries are +mutable so you can + +change their values. + +Then also we are adding +a new element. + +Fine. + +If you wanted a new element you +call it by the key that + +you already assigned. + +If the key already exists you +will just modify the value. + +Otherwise it will create a new +key and add that value. + +You can also check whether this +particular element is in + +the dictionary. + +But this must be the key. + +Whatever you are calling +here should be the + +key, not the value. + +It won't search for the value. + +It will search only for the +key, [UNINTELLIGIBLE] + +for that particular key because +you access the values + +through keys. + +Again here if it is not +in the list, actually + +I'm adding an element-- + +OK. + +OK. + +To compare in the list, suppose +I have a list 0, 1, 2. + +If I want to check whether +1 is in the + +list, how would I check? + +Do you have to go through +element by element? + +No, there's a shortcut. + +If 1 in list, right? + +If I want to check whether 1 is +not in the list, if I want + +to negate this, I would write +it 1 not in list. + +We just ignore the words. + +It's pretty much like English. + +OK? + +We just remove the words. + +OK. + +In the dictionary we do the +same thing through keys. + +If key A and, OK I'll +call it, say, D1. + +OK? + +And you actually call or you'd +search for the key, + +not the other way. + +OK. + +There is an interesting +part here. + +If you want to modify +the order-- + +actually I tell you that the +order C earlier, we couldn't + +guarantee the order, right? + +It was not the order we typed +because it starts at + +[UNINTELLIGIBLE] + +because we added at the +end actually, right? + +So actually you can't +guarantee the order. + +But we can sort it. + +But how do you sort it? + +We call the keys and +we sort the keys. + +Because remember, +every values-- + +if you want to access a +particular value, you access + +it through key. + +Actually, if you call the +dictionary, it doesn't know + +where these values are. + +Just you have to go to the +key to access the value. + +So if you want to do something +in the dictionary itself, you + +can do that only on keys. + +So if you want to sort +the dictionary, + +you sort it by keys. + +So you call the keys method +for the dictionary-- + +so it returns the list of +keys and you sort them. + +This is called chaining +methods. + +So I have chained the methods. + +I would have like two +methods, right? + +I call the keys. + +This first part actually returns +to this top key. + +Then you sort them. + +Yes? + +AUDIENCE: It doesn't look like +they're in alphabetical order? + +PROFESSOR: Oh, on this? + +Sorry. + +Let's see. + +OK. + +Let's see. + +Ooops. + +OK. + +Now they're sorted. + +OK. + +What was the problem? + +What was the problem there? + +Why it wasn't sorted? + +AUDIENCE: You have to +do it in two lines. + +PROFESSOR: Sorry? + +AUDIENCE: You have to call up +the keys and then sort it in a + +separate line? + +PROFESSOR: OK. + +The problem is in the logic. + +Actually, when you call this +function, method, you're + +actually sorting the keys +returned by this method. + +You're not actually going to +sort of the dictionary itself. + +You're sorting only the list +that was returned, right? + +The list of keys. + +Although the dictionary is +mutable, it wasn't sorted. + +Do you see the problem? + +So that's why when they called +keys equal to staff.keys I'm + +getting a list of keys. + +Then I'm sorting that list. + +And I'm printing that list. + +But if you want to go in a +particular order, if you want + +to access the dictionary in a +particular order, what could + +you do is you could do something +like keys is equal + +to staff.keys. + +Then you can store keys. + +Then for k in keys you can go +and iterate now, right? + +So you can say print +k and staff k. + +OK? + +So you can do this. + +But actually, Python provides a +way to iterate what keys and + +value pairs. + +That you do by calling +both elements? + +All the method items. + +The items return a list +of key-value pairs. + +If you call D1.items you get +a list of key-value pairs. + +You see that? + +And we are going to iterate +through individual elements. + +So first we start with this +and then second this. + +So that's a simpler way to +access every elements in the + +dictionary. + +Great. + +OK. + +Now we have an interesting +part, recursion. + +What's the principle +behind recursion? + +Anyone? + +What's the idea of recursion? + +Yes? + +AUDIENCE: The cause itself +is [INAUDIBLE] + +base case. + +And it saves a lot of money. + +PROFESSOR: Yes. + +The idea of recursion is, if +you have a problem, try to + +express the problem +in a simpler + +version of the same problem. + +So if you want to find factorial +n, try to express it + +in terms of factorial +n minus 1. + +So you could keep on doing +this till you come to + +factorial 1 for which you know +the explicit answer. + +Right? + +So you try to express the +problem in its simpler form. + +It would be useful +in many cases. + +Actually, in your next piece +you do have the problem. + +But be mindful. + +What's -- + +what makes it possible for +you to use the recursion? + +Only if you can express in terms +of the simpler version. + +Otherwise you can't. + +This is probably quite like the +induction you might have + +studied, mathematical +induction. + +I don't know whether you studied +it in high school, but + +it's quite like that. + +OK. + +So there are two parts +in recursion. + +The first one is +the base case. + +So for a factorial problem we +can express the factorial, say + +nth factorial, as any n in +to n minus 1 factorial. + +OK? + +So this would be our +recursive case. + +So what is a recursive case? + +Suppose we want to define a +function factorial A. OK? + +So what will be our +recursive case? + +AUDIENCE: A is greater than 0? + +PROFESSOR: I'm asking the +recursive function. + +What would be that? + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: n into 2. + +Factorial n minus 1 right? + +And you just return this. + +What would be your base case? + +If n is equal to 0, we know +factorial 0 is 1, right? + +What is factorial of 1? + +1. + +OK? + +But why in this program +we didn't have + +that particular line. + +Why we didn't have n equals 1? + +Why we didn't have that? + +AUDIENCE: Because it +always goes to 0? + +PROFESSOR: It always +goes 0, right? + +Because you can express 1 in +terms of 0 as well, right? + +So you don't need to actually +write this explicitly. + +Why? + +Because your recursive function +only depends on its + +previous value. + +So you need only one value in +advance Which means you need + +only one value for +your base case. + +So you can understand +this program, right? + +I'm not going to go +through that. + +But anyway when you write +a program always + +check its base case. + +So you have to start with +factorial 0 for this case. + +OK? + +And check one by one. + +Then you would know whether +the program is running + +correctly or not. + +So always start with +a simpler case. + +But remember in Fibonacci +series. + +OK. for Fibonacci series +can you give me + +the recursive function.? + +Yes. + +What is Fibonacci series? + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: OK. + +Yeah. + +That's great. + +So return say F of n minus +1 plus F of n minus 2. + +What is the Fibonacci series? + +You start from 0, you +add these elements. + +So 1. + +You add last two elements, 2. + +You add last two elements, 3. + +You add last two elements, 5. + +So you add last two elements. + +So if you want to find F of n, +you return F of n minus 1 and + +plus F of n minus 2. + +But here since you have two +elements, or you need to + +access two previous elements, +you need to define you base + +case accordingly. + +So for your base case, +F of 0, is what? + +Actually, that depends +on whether you + +start here or here. + +OK? + +You could do this. + +I'll go through an interesting +recursive example. + +OK. + +It's called a recursive +exponentiation. + +So I actually you can do an +exponentiation through + +recursive multiplication. + +Suppose you want to find 3 +to the power, say, of 10. + +Then how would you do that? + +You start by expressing +it in terms of its + +simpler version, right? + +So it will be 3 into +3 to the power 9. + +Sorry, 3 to the power 9. + +OK? + +So if you want to find that +nth power of number M, you + +would say M into M to +the power n minus 1. + +So now you have your +recursive case. + +What is the base case? + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: Yes, if +n is equal to 0. + +In Python you would test this +by two equal signs. + +If n is equal to 0, then what? + +AUDIENCE: Return 1. + +PROFESSOR: Return 1. + +OK? + +Why we have only one +base case here? + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: Sorry? + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: Yes. + +And because you're accessing +only one + +previous series, right? + +Fibonacci series. + +Similarly, if you want to +multiply something-- + +OK, here what we did is we +replaced this operator by + +recursively using +this operator. + +OK? + +Can you do the multiplication +by recursive addition? + +So can you replace this operator +by this operator? + +Yes. + +So how would you do this, for +example say 3 into 5? + +So how would you do it here? + +Tell me. + +What would this? + +AUDIENCE: 3 plus 3 times 4. + +PROFESSOR: 3 plus? + +AUDIENCE: 3 times 4. + +PROFESSOR: 3 times 4. + +Here? + +Come on, it's simple, right? + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: I'm insulting you. + +OK. + +What's the base case? + +That is interesting. + +What is the base case +if n is equal to 0? + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: OK. + +If n is equal to 0, that is 0. + +But that's fine. + +But there's another problem. + +The problem is you don't know +whether these values are + +positive or negative. + +So you can't just keep +on adding like this. + +This will work if +it's positive. + +But if it's negative, actually +you have to check. + +Which is sort of tricky +if you want to use the + +same recursive function. + +Otherwise you could have +an if condition here. + +If say n is greater +than 0, do this. + +Else-if you multiply n by minus +1 you negate that so it + +becomes positive. + +And do it the same way and +then that's the answer. + +So you could do that. + +But if you want to do it in the +same recursive case, then + +you had to follow this. + +If you have any questions, +come to the + +office hours on that. + +The final question is, final +example is, the Hanoi example. + +OK. + +This is very interesting. + +So here we have three towers; +source, target, and buffer. + +Suppose you have three disks. + +You want to move them from +source to target. + +And you can always have a +smaller disk on top of a + +bigger disk. + +Then how would you move? + +OK? + +So can you express this problem +in a simpler version? + +So now we have three disks. + +You want to move +them to target. + +So can you express it in +a simpler version? + +Come on. + +Just in plain English, +how would you do it? + +Without looking at +the program. + +Because Python is very robust. + +So if you read the program +you get it in English. + +So any ideas? + +OK. + +We have to here move the last +disk to target, right? + +But that's the hardest part. + +So before doing that you have +to move this somewhere else. + +So let's move it to buffer. + +Done. + +How would you move this? + +Now you can move it to target. + +OK. + +Now what would you do? + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: OK. + +Sorry. + +Yeah, OK? + +No. + +What would you do? + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: You can only move +this to the buffer, right? + +AUDIENCE: [INAUDIBLE] + +[? + +PROFESSOR: Not the target. + +OK. + +So we made some mistake +earlier. + +Remember? + +The problem is because we didn't +think recursively. + +OK. + +Let's think recursively. + +Source, target, buffer. + +Sorry. + +Suppose we have only one disk. + +Then you can simply +move to target. + +OK? + +So a condition is if there's +only one disk, just move it to + +the target. + +So if n is equal to 1 +we always move from + +move source to target. + +OK? + +Suppose you have two. + +Then what would you do? + +You move the top +one to buffer. + +OK? + +So move source to buffer. + +Then you move the next disk +from source to target. + +So now it's source to target. + +And finally you move +it from the buffer. + +All right? + +Now we have a very nice +recursive case. + +If you have two, we move from +source to buffer, then source + +to target, then from +buffer to target. + +So if you look at this example +I'm checking if + +n is equal to 1. + +If it is 1, just I'm moving +from source to target. + +If it is greater than +n, what would I do? + +And that first assert statement +is just there to + +make sure that n is +greater than 0. + +Otherwise it's meaningless, +right? + +You need to have this. + +You can't have negative this. + +So what would be the next +step if you have + +more than one disk? + +Suppose you have two disks. + +Then what would you do? + +You move the top disk +or whatever on + +the top to the buffer. + +For this simple example +it was just one disk. + +But suppose you had more disks +on top of the last disk? + +So you would have moved +all of them to buffer. + +You don't have to worry +how you move it. + +But you have to move +it anyway. + +After moving that, you can +leisurely move this big disk + +to the top, to the target. + +OK? + +Finally, you bring back all +of them here, right? + +For you first operation, for +your first operation, from + +source to target, you have +to move all of them, the + +[UNINTELLIGIBLE]. + +You could have used target +as your buffer. + +OK? + +So that's why in this line I'm +using source as source. + +But the second argument, which +should have been the target, + +is now buffer because my current +target is buffer for + +the top n minus 1 disk. + +But my buffer is +now the target. + +OK. + +Because I can use the target +as buffer for the movement. + +Then I moved from source to the +target, the last big disk. + +OK? + +For that I can use buffer +as my buffer. + +Then finally I bring back from +buffer to target using source + +as my buffer. + +OK? + +So the thing is if you want to +have a recursive problem you + +can do it in two ways. + +One thing, you can start +thinking how to express this + +problem in its simpler version +like how you thought about the + +Fibonacci series, +for instance. + +Or else, you can start from +its base case, the most + +fundamental situation. + +So here it's n equal to +1, but this doesn't + +give you enough context. + +So you go to the next level, n +is equal to 2, and you have + +the answer. + +Right? \ No newline at end of file diff --git a/Fq0mvAbzUrY.txt b/Fq0mvAbzUrY.txt new file mode 100644 index 0000000000000000000000000000000000000000..6b3c2cd1cacb0b4e254135a8da079b658e6b79f0 --- /dev/null +++ b/Fq0mvAbzUrY.txt @@ -0,0 +1,9563 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +view additional materials from hundreds + + align:start position:0% +view additional materials from hundreds + + + align:start position:0% +view additional materials from hundreds +of MIT courses visit mitop courseware at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu our topic today + + align:start position:0% +ocw.mit.edu our topic today + + + align:start position:0% +ocw.mit.edu our topic today +is the influential movement called + + align:start position:0% +is the influential movement called + + + align:start position:0% +is the influential movement called +Italian + + align:start position:0% +Italian + + + align:start position:0% +Italian +neorealism a um a movement of uh + + align:start position:0% +neorealism a um a movement of uh + + + align:start position:0% +neorealism a um a movement of uh +filmmakers that arose in Italy at the + + align:start position:0% +filmmakers that arose in Italy at the + + + align:start position:0% +filmmakers that arose in Italy at the +end of the second world war and had + + align:start position:0% +end of the second world war and had + + + align:start position:0% +end of the second world war and had +although it was a very short lived + + align:start position:0% +although it was a very short lived + + + align:start position:0% +although it was a very short lived +movement lasted only six or seven years + + align:start position:0% +movement lasted only six or seven years + + + align:start position:0% +movement lasted only six or seven years +uh before it kind of uh dissolved of its + + align:start position:0% +uh before it kind of uh dissolved of its + + + align:start position:0% +uh before it kind of uh dissolved of its +own of its own way uh in part + + align:start position:0% +own of its own way uh in part + + + align:start position:0% +own of its own way uh in part +incidentally because although the films + + align:start position:0% +incidentally because although the films + + + align:start position:0% +incidentally because although the films +were very successful with critics and + + align:start position:0% +were very successful with critics and + + + align:start position:0% +were very successful with critics and +several of the neorealist films won + + align:start position:0% +several of the neorealist films won + + + align:start position:0% +several of the neorealist films won +Academy Awards as the best foreign film + + align:start position:0% +Academy Awards as the best foreign film + + + align:start position:0% +Academy Awards as the best foreign film +of the year in uh 1946 and then again in + + align:start position:0% +of the year in uh 1946 and then again in + + + align:start position:0% +of the year in uh 1946 and then again in +1948 when when the film you're going to + + align:start position:0% +1948 when when the film you're going to + + + align:start position:0% +1948 when when the film you're going to +see tonight bicycle thieves won the + + align:start position:0% +see tonight bicycle thieves won the + + + align:start position:0% +see tonight bicycle thieves won the +award despite that Acclaim and even + + align:start position:0% +award despite that Acclaim and even + + + align:start position:0% +award despite that Acclaim and even +Global success uh the the movement sort + + align:start position:0% +Global success uh the the movement sort + + + align:start position:0% +Global success uh the the movement sort +of petered out although its influence as + + align:start position:0% +of petered out although its influence as + + + align:start position:0% +of petered out although its influence as +I've suggested was very great one reason + + align:start position:0% +I've suggested was very great one reason + + + align:start position:0% +I've suggested was very great one reason +the movement petered out was that uh + + align:start position:0% +the movement petered out was that uh + + + align:start position:0% +the movement petered out was that uh +forces in Italian Society Chambers of + + align:start position:0% +forces in Italian Society Chambers of + + + align:start position:0% +forces in Italian Society Chambers of +Commerce types uh people who were + + align:start position:0% +Commerce types uh people who were + + + align:start position:0% +Commerce types uh people who were +interested in encouraging the rebuilding + + align:start position:0% +interested in encouraging the rebuilding + + + align:start position:0% +interested in encouraging the rebuilding +of a devastate of the devastated uh uh + + align:start position:0% +of a devastate of the devastated uh uh + + + align:start position:0% +of a devastate of the devastated uh uh +cities of Italy function a consequence + + align:start position:0% +cities of Italy function a consequence + + + align:start position:0% +cities of Italy function a consequence +of the of the second world war those + + align:start position:0% +of the of the second world war those + + + align:start position:0% +of the of the second world war those +folks began to feel that the messages + + align:start position:0% +folks began to feel that the messages + + + align:start position:0% +folks began to feel that the messages +coming from neorealist films were too + + align:start position:0% +coming from neorealist films were too + + + align:start position:0% +coming from neorealist films were too +negative uh and were discouraging + + align:start position:0% +negative uh and were discouraging + + + align:start position:0% +negative uh and were discouraging +foreign investors uh uh so although it + + align:start position:0% +foreign investors uh uh so although it + + + align:start position:0% +foreign investors uh uh so although it +was a very remarkable movement it it it + + align:start position:0% +was a very remarkable movement it it it + + + align:start position:0% +was a very remarkable movement it it it +lasted only as I say a short time but + + align:start position:0% +lasted only as I say a short time but + + + align:start position:0% +lasted only as I say a short time but +its influence ramified very very very + + align:start position:0% +its influence ramified very very very + + + align:start position:0% +its influence ramified very very very +broadly uh we can trace its influence uh + + align:start position:0% +broadly uh we can trace its influence uh + + + align:start position:0% +broadly uh we can trace its influence uh +to virtually every National Cinema uh + + align:start position:0% +to virtually every National Cinema uh + + + align:start position:0% +to virtually every National Cinema uh +that that came after it and there are + + align:start position:0% +that that came after it and there are + + + align:start position:0% +that that came after it and there are +there are certain very particular + + align:start position:0% +there are certain very particular + + + align:start position:0% +there are certain very particular +influences that one can trace from the + + align:start position:0% +influences that one can trace from the + + + align:start position:0% +influences that one can trace from the +neorealist movement to certain American + + align:start position:0% +neorealist movement to certain American + + + align:start position:0% +neorealist movement to certain American +directors of film Noir in the 40s and + + align:start position:0% +directors of film Noir in the 40s and + + + align:start position:0% +directors of film Noir in the 40s and +early 50s to certain very interesting + + align:start position:0% +early 50s to certain very interesting + + + align:start position:0% +early 50s to certain very interesting +and historically curious forms of + + align:start position:0% +and historically curious forms of + + + align:start position:0% +and historically curious forms of +Television that emerged in the early + + align:start position:0% +Television that emerged in the early + + + align:start position:0% +Television that emerged in the early +years of American television that were + + align:start position:0% +years of American television that were + + + align:start position:0% +years of American television that were +deeply imitative of and influenced by + + align:start position:0% +deeply imitative of and influenced by + + + align:start position:0% +deeply imitative of and influenced by +Italian neorealist + + align:start position:0% +Italian neorealist + + + align:start position:0% +Italian neorealist +movies there was the man that many would + + align:start position:0% +movies there was the man that many would + + + align:start position:0% +movies there was the man that many would +identify as the greatest of all Indian + + align:start position:0% +identify as the greatest of all Indian + + + align:start position:0% +identify as the greatest of all Indian +directors Sagi Ray uh was directly + + align:start position:0% +directors Sagi Ray uh was directly + + + align:start position:0% +directors Sagi Ray uh was directly +inspired to make movies by The Bicycle + + align:start position:0% +inspired to make movies by The Bicycle + + + align:start position:0% +inspired to make movies by The Bicycle +Thief and he made a a a series of three + + align:start position:0% +Thief and he made a a a series of three + + + align:start position:0% +Thief and he made a a a series of three +films that are essentially a form of + + align:start position:0% +films that are essentially a form of + + + align:start position:0% +films that are essentially a form of +Italian neorealism moved to India uh + + align:start position:0% +Italian neorealism moved to India uh + + + align:start position:0% +Italian neorealism moved to India uh +wonderful Trilogy of of uh films some of + + align:start position:0% +wonderful Trilogy of of uh films some of + + + align:start position:0% +wonderful Trilogy of of uh films some of +them actually about the Untouchable + + align:start position:0% +them actually about the Untouchable + + + align:start position:0% +them actually about the Untouchable +classes in in India called the Apu + + align:start position:0% +classes in in India called the Apu + + + align:start position:0% +classes in in India called the Apu +Trilogy and they are they remain among + + align:start position:0% +Trilogy and they are they remain among + + + align:start position:0% +Trilogy and they are they remain among +the the most treasured uh forms of + + align:start position:0% +the the most treasured uh forms of + + + align:start position:0% +the the most treasured uh forms of +Indian of Indian film uh the Italian + + align:start position:0% +Indian of Indian film uh the Italian + + + align:start position:0% +Indian of Indian film uh the Italian +neorealist had had a profound influence + + align:start position:0% +neorealist had had a profound influence + + + align:start position:0% +neorealist had had a profound influence +on other European cinemas as well uh and + + align:start position:0% +on other European cinemas as well uh and + + + align:start position:0% +on other European cinemas as well uh and +most particularly can be said to be the + + align:start position:0% +most particularly can be said to be the + + + align:start position:0% +most particularly can be said to be the +originating movement behind the French + + align:start position:0% +originating movement behind the French + + + align:start position:0% +originating movement behind the French +Nel new velv vag the new wave movement + + align:start position:0% +Nel new velv vag the new wave movement + + + align:start position:0% +Nel new velv vag the new wave movement +that uh in France that emerges at the + + align:start position:0% +that uh in France that emerges at the + + + align:start position:0% +that uh in France that emerges at the +end of the 50s and the early 60s and uh + + align:start position:0% +end of the 50s and the early 60s and uh + + + align:start position:0% +end of the 50s and the early 60s and uh +in involved such now + + align:start position:0% +in involved such now + + + align:start position:0% +in involved such now +recognized uh such directors uh now + + align:start position:0% +recognized uh such directors uh now + + + align:start position:0% +recognized uh such directors uh now +recognized as major figures in the + + align:start position:0% +recognized as major figures in the + + + align:start position:0% +recognized as major figures in the +history of film as Jean L Godard and + + align:start position:0% +history of film as Jean L Godard and + + + align:start position:0% +history of film as Jean L Godard and +Fran + + align:start position:0% +Fran + + + align:start position:0% +Fran +trufo so it was although a short live + + align:start position:0% +trufo so it was although a short live + + + align:start position:0% +trufo so it was although a short live +movement a profoundly influential one + + align:start position:0% +movement a profoundly influential one + + + align:start position:0% +movement a profoundly influential one +and it produced some enduring and + + align:start position:0% +and it produced some enduring and + + + align:start position:0% +and it produced some enduring and +beautiful and I guess I would say + + align:start position:0% +beautiful and I guess I would say + + + align:start position:0% +beautiful and I guess I would say +Immortal films the most famous and + + align:start position:0% +Immortal films the most famous and + + + align:start position:0% +Immortal films the most famous and +perhaps in some ways the most perfect of + + align:start position:0% +perhaps in some ways the most perfect of + + + align:start position:0% +perhaps in some ways the most perfect of +those films is the one you're going to + + align:start position:0% +those films is the one you're going to + + + align:start position:0% +those films is the one you're going to +see tonight bicycle thieves and I'll + + align:start position:0% +see tonight bicycle thieves and I'll + + + align:start position:0% +see tonight bicycle thieves and I'll +talk a bit about that film in my + + align:start position:0% +talk a bit about that film in my + + + align:start position:0% +talk a bit about that film in my +introduction to the lecture this evening + + align:start position:0% +introduction to the lecture this evening + + + align:start position:0% +introduction to the lecture this evening +I want to begin though by giving you a + + align:start position:0% +I want to begin though by giving you a + + + align:start position:0% +I want to begin though by giving you a +sense of how neorealism feels a kind of + + align:start position:0% +sense of how neorealism feels a kind of + + + align:start position:0% +sense of how neorealism feels a kind of +a kind of a kind of distilled version of + + align:start position:0% +a kind of a kind of distilled version of + + + align:start position:0% +a kind of a kind of distilled version of +or distilled embodiment of many of the + + align:start position:0% +or distilled embodiment of many of the + + + align:start position:0% +or distilled embodiment of many of the +deepest principles of neorealism uh and + + align:start position:0% +deepest principles of neorealism uh and + + + align:start position:0% +deepest principles of neorealism uh and +uh in order to do that I want to show + + align:start position:0% +uh in order to do that I want to show + + + align:start position:0% +uh in order to do that I want to show +you a clip from the very beginning of + + align:start position:0% +you a clip from the very beginning of + + + align:start position:0% +you a clip from the very beginning of +the film you're going to see tonight so + + align:start position:0% +the film you're going to see tonight so + + + align:start position:0% +the film you're going to see tonight so +you'll see this beginning twice + + align:start position:0% +you'll see this beginning twice + + + align:start position:0% +you'll see this beginning twice +hopefully the second time you see it + + align:start position:0% +hopefully the second time you see it + + + align:start position:0% +hopefully the second time you see it +you'll be alive to More Alive to some of + + align:start position:0% +you'll be alive to More Alive to some of + + + align:start position:0% +you'll be alive to More Alive to some of +its implications so here is the very + + align:start position:0% +its implications so here is the very + + + align:start position:0% +its implications so here is the very +opening of bicycle thieves and one of + + align:start position:0% +opening of bicycle thieves and one of + + + align:start position:0% +opening of bicycle thieves and one of +the things I want to ask you to watch + + align:start position:0% +the things I want to ask you to watch + + + align:start position:0% +the things I want to ask you to watch +for is first how much information how + + align:start position:0% +for is first how much information how + + + align:start position:0% +for is first how much information how +much visual information dramatic + + align:start position:0% +much visual information dramatic + + + align:start position:0% +much visual information dramatic +information becomes available to you + + align:start position:0% +information becomes available to you + + + align:start position:0% +information becomes available to you +under the titles uh and then how + + align:start position:0% +under the titles uh and then how + + + align:start position:0% +under the titles uh and then how +fluently and fluidly the film moves out + + align:start position:0% +fluently and fluidly the film moves out + + + align:start position:0% +fluently and fluidly the film moves out +of the title sequence into a kind of + + align:start position:0% +of the title sequence into a kind of + + + align:start position:0% +of the title sequence into a kind of +continuation of the drama that's + + align:start position:0% +continuation of the drama that's + + + align:start position:0% +continuation of the drama that's +articulated in that title sequence on + + align:start position:0% +articulated in that title sequence on + + + align:start position:0% +articulated in that title sequence on +the surface this little anecdote at the + + align:start position:0% +the surface this little anecdote at the + + + align:start position:0% +the surface this little anecdote at the +very beginning of the film seems very + + align:start position:0% +very beginning of the film seems very + + + align:start position:0% +very beginning of the film seems very +modest and uh one might even think of it + + align:start position:0% +modest and uh one might even think of it + + + align:start position:0% +modest and uh one might even think of it +as simply expository that is to + + align:start position:0% +as simply expository that is to + + + align:start position:0% +as simply expository that is to +providing information to the audience so + + align:start position:0% +providing information to the audience so + + + align:start position:0% +providing information to the audience so +that they can get on with the story uh + + align:start position:0% +that they can get on with the story uh + + + align:start position:0% +that they can get on with the story uh +as I hope you'll recognize and as I'll + + align:start position:0% +as I hope you'll recognize and as I'll + + + align:start position:0% +as I hope you'll recognize and as I'll +try to show you briefly after I've shown + + align:start position:0% +try to show you briefly after I've shown + + + align:start position:0% +try to show you briefly after I've shown +you the clip much more is going on than + + align:start position:0% +you the clip much more is going on than + + + align:start position:0% +you the clip much more is going on than +that and it's a particularly uh + + align:start position:0% +that and it's a particularly uh + + + align:start position:0% +that and it's a particularly uh +wonderful example of the way in which + + align:start position:0% +wonderful example of the way in which + + + align:start position:0% +wonderful example of the way in which +the best neorealist films generate a + + align:start position:0% +the best neorealist films generate a + + + align:start position:0% +the best neorealist films generate a +kind of texture a kind of density what + + align:start position:0% +kind of texture a kind of density what + + + align:start position:0% +kind of texture a kind of density what +I've sometimes called a multiplicity + + align:start position:0% +I've sometimes called a multiplicity + + + align:start position:0% +I've sometimes called a multiplicity +that we have suggested in this course is + + align:start position:0% +that we have suggested in this course is + + + align:start position:0% +that we have suggested in this course is +one of the fundamental ways in which you + + align:start position:0% +one of the fundamental ways in which you + + + align:start position:0% +one of the fundamental ways in which you +can distinguish between entertainment + + align:start position:0% +can distinguish between entertainment + + + align:start position:0% +can distinguish between entertainment +and serious entertainment or between + + align:start position:0% +and serious entertainment or between + + + align:start position:0% +and serious entertainment or between +entertainment and art when items and + + align:start position:0% +entertainment and art when items and + + + align:start position:0% +entertainment and art when items and +objects begin to have this multiplicity + + align:start position:0% +objects begin to have this multiplicity + + + align:start position:0% +objects begin to have this multiplicity +when they begin to serve Ser multiple + + align:start position:0% +when they begin to serve Ser multiple + + + align:start position:0% +when they begin to serve Ser multiple +functions not just a single function + + align:start position:0% +functions not just a single function + + + align:start position:0% +functions not just a single function +you're in the presence of something not + + align:start position:0% +you're in the presence of something not + + + align:start position:0% +you're in the presence of something not +only complex but something that + + align:start position:0% +only complex but something that + + + align:start position:0% +only complex but something that +acknowledges the complexity of the world + + align:start position:0% +acknowledges the complexity of the world + + + align:start position:0% +acknowledges the complexity of the world +in some in some respects and this + + align:start position:0% +in some in some respects and this + + + align:start position:0% +in some in some respects and this +opening sequence of bicycle thieves does + + align:start position:0% +opening sequence of bicycle thieves does + + + align:start position:0% +opening sequence of bicycle thieves does +this with remarkable economy so here's + + align:start position:0% +this with remarkable economy so here's + + + align:start position:0% +this with remarkable economy so here's +the beginning of the film + + align:start position:0% +the beginning of the film + + + align:start position:0% +the beginning of the film +[Music] + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +e + + align:start position:0% +e + + + align:start position:0% +e +[Music] + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +chy + + align:start position:0% + + + + align:start position:0% + +rich rich + + align:start position:0% +rich rich + + + align:start position:0% +rich rich +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +[Applause] + + align:start position:0% + + + + align:start position:0% + +Greg can you freeze it for a + + align:start position:0% +Greg can you freeze it for a + + + align:start position:0% +Greg can you freeze it for a +second one thing I should mention while + + align:start position:0% +second one thing I should mention while + + + align:start position:0% +second one thing I should mention while +you're watching this to interrupt the + + align:start position:0% +you're watching this to interrupt the + + + align:start position:0% +you're watching this to interrupt the +sequence for a moment + + align:start position:0% +sequence for a moment + + + align:start position:0% +sequence for a moment +the activity that you see taking place + + align:start position:0% +the activity that you see taking place + + + align:start position:0% +the activity that you see taking place +under the titles is supposed to be + + align:start position:0% +under the titles is supposed to be + + + align:start position:0% +under the titles is supposed to be +confusing at first although after a + + align:start position:0% +confusing at first although after a + + + align:start position:0% +confusing at first although after a +while it begins to clarify perhaps + + align:start position:0% +while it begins to clarify perhaps + + + align:start position:0% +while it begins to clarify perhaps +you're not fully clear what is going on + + align:start position:0% +you're not fully clear what is going on + + + align:start position:0% +you're not fully clear what is going on +until the titles appear and you see + + align:start position:0% +until the titles appear and you see + + + align:start position:0% +until the titles appear and you see +these men assembling around that + + align:start position:0% +these men assembling around that + + + align:start position:0% +these men assembling around that +staircase there where a man with a A + + align:start position:0% +staircase there where a man with a A + + + align:start position:0% +staircase there where a man with a A +list is speaking to them what is going + + align:start position:0% +list is speaking to them what is going + + + align:start position:0% +list is speaking to them what is going +on here is what in in in in the United + + align:start position:0% +on here is what in in in in the United + + + align:start position:0% +on here is what in in in in the United +States in the in the 40s and 50s on the + + align:start position:0% +States in the in the 40s and 50s on the + + + align:start position:0% +States in the in the 40s and 50s on the +on the docks in New York they called The + + align:start position:0% +on the docks in New York they called The + + + align:start position:0% +on the docks in New York they called The +Shape Up and a shape up is a place where + + align:start position:0% +Shape Up and a shape up is a place where + + + align:start position:0% +Shape Up and a shape up is a place where +men who are eager for work sort of come + + align:start position:0% +men who are eager for work sort of come + + + align:start position:0% +men who are eager for work sort of come +and hang around and wait for the boss + + align:start position:0% +and hang around and wait for the boss + + + align:start position:0% +and hang around and wait for the boss +the the the foreman or the or the hiring + + align:start position:0% +the the the foreman or the or the hiring + + + align:start position:0% +the the the foreman or the or the hiring +boss to pick them out of the crowd shape + + align:start position:0% +boss to pick them out of the crowd shape + + + align:start position:0% +boss to pick them out of the crowd shape +ups are always unpleasant experiences + + align:start position:0% +ups are always unpleasant experiences + + + align:start position:0% +ups are always unpleasant experiences +because there are many people who are + + align:start position:0% +because there are many people who are + + + align:start position:0% +because there are many people who are +excluded and the people who are chosen + + align:start position:0% +excluded and the people who are chosen + + + align:start position:0% +excluded and the people who are chosen +are often this was especially true on + + align:start position:0% +are often this was especially true on + + + align:start position:0% +are often this was especially true on +the New York Waterfront in the days when + + align:start position:0% +the New York Waterfront in the days when + + + align:start position:0% +the New York Waterfront in the days when +which I know about because my father was + + align:start position:0% +which I know about because my father was + + + align:start position:0% +which I know about because my father was +a long shoreman for a while it was a + + align:start position:0% +a long shoreman for a while it was a + + + align:start position:0% +a long shoreman for a while it was a +particularly bad thing in the New York + + align:start position:0% +particularly bad thing in the New York + + + align:start position:0% +particularly bad thing in the New York +Waterfront because you had to know + + align:start position:0% +Waterfront because you had to know + + + align:start position:0% +Waterfront because you had to know +somebody to get work I don't know if + + align:start position:0% +somebody to get work I don't know if + + + align:start position:0% +somebody to get work I don't know if +that's an implication here or not + + align:start position:0% +that's an implication here or not + + + align:start position:0% +that's an implication here or not +although you'll see as the men complain + + align:start position:0% +although you'll see as the men complain + + + align:start position:0% +although you'll see as the men complain +that some of them have that suspicion in + + align:start position:0% +that some of them have that suspicion in + + + align:start position:0% +that some of them have that suspicion in +any case what's going on here is what is + + align:start position:0% +any case what's going on here is what is + + + align:start position:0% +any case what's going on here is what is +called a shape up men are gathered + + align:start position:0% +called a shape up men are gathered + + + align:start position:0% +called a shape up men are gathered +around men who are unemployed looking + + align:start position:0% +around men who are unemployed looking + + + align:start position:0% +around men who are unemployed looking +for + + align:start position:0% + + + + align:start position:0% + +work + + align:start position:0% + + + + align:start position:0% + +for + + align:start position:0% + + + + align:start position:0% + +speee fore + + align:start position:0% +speee fore + + + align:start position:0% +speee fore +spe + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +speee + + align:start position:0% + + + + align:start position:0% + +speee + + align:start position:0% +speee + + + align:start position:0% +speee +fore + + align:start position:0% +fore + + + align:start position:0% +fore +spee + + align:start position:0% + + + + align:start position:0% + +spe + + align:start position:0% + + + + align:start position:0% + +fore + + align:start position:0% + + + + align:start position:0% + +speee + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +for GU for + + align:start position:0% +for GU for + + + align:start position:0% +for GU for +spe fore spe + + align:start position:0% + + + + align:start position:0% + +speee spe + + align:start position:0% + + + + align:start position:0% + +I wish I could let the scene run on but + + align:start position:0% +I wish I could let the scene run on but + + + align:start position:0% +I wish I could let the scene run on but +I hope you I hope you I can tell some of + + align:start position:0% +I hope you I hope you I can tell some of + + + align:start position:0% +I hope you I hope you I can tell some of +you are responding to what you saw there + + align:start position:0% +you are responding to what you saw there + + + align:start position:0% +you are responding to what you saw there +make some observations about what you + + align:start position:0% +make some observations about what you + + + align:start position:0% +make some observations about what you +saw there what that in that introduction + + align:start position:0% +saw there what that in that introduction + + + align:start position:0% +saw there what that in that introduction +what do we learn as an + + align:start position:0% +what do we learn as an + + + align:start position:0% +what do we learn as an +audience you have to be fast I only have + + align:start position:0% +audience you have to be fast I only have + + + align:start position:0% +audience you have to be fast I only have +a few minutes here yes for all right one + + align:start position:0% +a few minutes here yes for all right one + + + align:start position:0% +a few minutes here yes for all right one +thing we know is that there's a lot of + + align:start position:0% +thing we know is that there's a lot of + + + align:start position:0% +thing we know is that there's a lot of +unemployment in this a lot right and + + align:start position:0% +unemployment in this a lot right and + + + align:start position:0% +unemployment in this a lot right and +there's a lot of discontent and then the + + align:start position:0% +there's a lot of discontent and then the + + + align:start position:0% +there's a lot of discontent and then the +minute he says I don't have a bicycle + + align:start position:0% +minute he says I don't have a bicycle + + + align:start position:0% +minute he says I don't have a bicycle +virtually everyone else in the crowd + + align:start position:0% +virtually everyone else in the crowd + + + align:start position:0% +virtually everyone else in the crowd +says I have a bicycle everyone is + + align:start position:0% +says I have a bicycle everyone is + + + align:start position:0% +says I have a bicycle everyone is +desperate for a job not just Richi + + align:start position:0% +desperate for a job not just Richi + + + align:start position:0% +desperate for a job not just Richi +that's right uh so there and he he we we + + align:start position:0% +that's right uh so there and he he we we + + + align:start position:0% +that's right uh so there and he he we we +learn how grateful he is but also how + + align:start position:0% +learn how grateful he is but also how + + + align:start position:0% +learn how grateful he is but also how +troubled he is what is what's the + + align:start position:0% +troubled he is what is what's the + + + align:start position:0% +troubled he is what is what's the +evidence in the film that he is really + + align:start position:0% +evidence in the film that he is really + + + align:start position:0% +evidence in the film that he is really +very unha very very troubled by the fact + + align:start position:0% +very unha very very troubled by the fact + + + align:start position:0% +very unha very very troubled by the fact +that he doesn't have a bicycle to get + + align:start position:0% +that he doesn't have a bicycle to get + + + align:start position:0% +that he doesn't have a bicycle to get +this job after so long what's the most + + align:start position:0% +this job after so long what's the most + + + align:start position:0% +this job after so long what's the most +dramatic piece of evidence we see that + + align:start position:0% +dramatic piece of evidence we see that + + + align:start position:0% +dramatic piece of evidence we see that +he's distracted by his anxiety + + align:start position:0% + + + + align:start position:0% + +H he doesn't help her with the water he + + align:start position:0% +H he doesn't help her with the water he + + + align:start position:0% +H he doesn't help her with the water he +doesn't help his wife with the water yes + + align:start position:0% +doesn't help his wife with the water yes + + + align:start position:0% +doesn't help his wife with the water yes +it's a very dramatic scene isn't it uh + + align:start position:0% +it's a very dramatic scene isn't it uh + + + align:start position:0% +it's a very dramatic scene isn't it uh +she she's walking behind him carrying + + align:start position:0% +she she's walking behind him carrying + + + align:start position:0% +she she's walking behind him carrying +these two heavy and he doesn't ignore + + align:start position:0% +these two heavy and he doesn't ignore + + + align:start position:0% +these two heavy and he doesn't ignore +her because he's a a nasty patriarch who + + align:start position:0% +her because he's a a nasty patriarch who + + + align:start position:0% +her because he's a a nasty patriarch who +thinks that women should carry water uh + + align:start position:0% +thinks that women should carry water uh + + + align:start position:0% +thinks that women should carry water uh +he he's so distracted he doesn't notice + + align:start position:0% +he he's so distracted he doesn't notice + + + align:start position:0% +he he's so distracted he doesn't notice +it and in fact what he walks down that + + align:start position:0% +it and in fact what he walks down that + + + align:start position:0% +it and in fact what he walks down that +that little incline and looks back and + + align:start position:0% +that little incline and looks back and + + + align:start position:0% +that little incline and looks back and +sees her struggling goes back and as + + align:start position:0% +sees her struggling goes back and as + + + align:start position:0% +sees her struggling goes back and as +soon as he recognizes it he takes one + + align:start position:0% +soon as he recognizes it he takes one + + + align:start position:0% +soon as he recognizes it he takes one +from her and it's significant isn't it + + align:start position:0% +from her and it's significant isn't it + + + align:start position:0% +from her and it's significant isn't it +that he takes only one from her is if + + align:start position:0% +that he takes only one from her is if + + + align:start position:0% +that he takes only one from her is if +they're really Partners I mean and it's + + align:start position:0% +they're really Partners I mean and it's + + + align:start position:0% +they're really Partners I mean and it's +also what else is significant she + + align:start position:0% +also what else is significant she + + + align:start position:0% +also what else is significant she +doesn't yell at him she doesn't say my + + align:start position:0% +doesn't yell at him she doesn't say my + + + align:start position:0% +doesn't yell at him she doesn't say my +God Richi what kind of a pig are you + + align:start position:0% +God Richi what kind of a pig are you + + + align:start position:0% +God Richi what kind of a pig are you +making me carry all this stuff by myself + + align:start position:0% +making me carry all this stuff by myself + + + align:start position:0% +making me carry all this stuff by myself +right because she shares his his uh + + align:start position:0% +right because she shares his his uh + + + align:start position:0% +right because she shares his his uh +anxiety and his concern doesn't she U + + align:start position:0% +anxiety and his concern doesn't she U + + + align:start position:0% +anxiety and his concern doesn't she U +so on the surface what the the the SE + + align:start position:0% +so on the surface what the the the SE + + + align:start position:0% +so on the surface what the the the SE +the scene certainly dramatizes richi's + + align:start position:0% +the scene certainly dramatizes richi's + + + align:start position:0% +the scene certainly dramatizes richi's +desperate need for for for a job and the + + align:start position:0% +desperate need for for for a job and the + + + align:start position:0% +desperate need for for for a job and the +fact that he's one of many people in a + + align:start position:0% +fact that he's one of many people in a + + + align:start position:0% +fact that he's one of many people in a +similar situation but what does it tell + + align:start position:0% +similar situation but what does it tell + + + align:start position:0% +similar situation but what does it tell +us about his marriage on the basis of + + align:start position:0% +us about his marriage on the basis of + + + align:start position:0% +us about his marriage on the basis of +these detail what you just saw in this + + align:start position:0% +these detail what you just saw in this + + + align:start position:0% +these detail what you just saw in this +beginning do you think he has a good + + align:start position:0% +beginning do you think he has a good + + + align:start position:0% +beginning do you think he has a good +marriage that he has a good relationship + + align:start position:0% +marriage that he has a good relationship + + + align:start position:0% +marriage that he has a good relationship +with his wife that that that it's a + + align:start position:0% +with his wife that that that it's a + + + align:start position:0% +with his wife that that that it's a +mutually trusting relationship that they + + align:start position:0% +mutually trusting relationship that they + + + align:start position:0% +mutually trusting relationship that they +of course of course right and how do we + + align:start position:0% +of course of course right and how do we + + + align:start position:0% +of course of course right and how do we +know that we know that from that detail + + align:start position:0% +know that we know that from that detail + + + align:start position:0% +know that we know that from that detail +now the detail does not Advance the plot + + align:start position:0% +now the detail does not Advance the plot + + + align:start position:0% +now the detail does not Advance the plot +in the sense of telling us anything + + align:start position:0% +in the sense of telling us anything + + + align:start position:0% +in the sense of telling us anything +further about his need for the bicycle + + align:start position:0% +further about his need for the bicycle + + + align:start position:0% +further about his need for the bicycle +or his unemployment but it does reveal + + align:start position:0% +or his unemployment but it does reveal + + + align:start position:0% +or his unemployment but it does reveal +to us something about their marriage + + align:start position:0% +to us something about their marriage + + + align:start position:0% +to us something about their marriage +about the kind of man is about the kind + + align:start position:0% +about the kind of man is about the kind + + + align:start position:0% +about the kind of man is about the kind +of woman she is right uh so that it's a + + align:start position:0% +of woman she is right uh so that it's a + + + align:start position:0% +of woman she is right uh so that it's a +moment in which his anxiety about his + + align:start position:0% +moment in which his anxiety about his + + + align:start position:0% +moment in which his anxiety about his +job is maybe the primary thing we see + + align:start position:0% +job is maybe the primary thing we see + + + align:start position:0% +job is maybe the primary thing we see +but what is also dramatized for us is + + align:start position:0% +but what is also dramatized for us is + + + align:start position:0% +but what is also dramatized for us is +the nature of their relationship and + + align:start position:0% +the nature of their relationship and + + + align:start position:0% +the nature of their relationship and +it's dramatized for us without anyone + + align:start position:0% +it's dramatized for us without anyone + + + align:start position:0% +it's dramatized for us without anyone +coming out and saying let me show you a + + align:start position:0% +coming out and saying let me show you a + + + align:start position:0% +coming out and saying let me show you a +mutually engaged couple who depend on + + align:start position:0% +mutually engaged couple who depend on + + + align:start position:0% +mutually engaged couple who depend on +each other and who survive in part + + align:start position:0% +each other and who survive in part + + + align:start position:0% +each other and who survive in part +because they share each other's troubles + + align:start position:0% +because they share each other's troubles + + + align:start position:0% +because they share each other's troubles +people whose respect for each other is + + align:start position:0% +people whose respect for each other is + + + align:start position:0% +people whose respect for each other is +so total that even when one of them + + align:start position:0% +so total that even when one of them + + + align:start position:0% +so total that even when one of them +commits a a re a really uh uh mean or at + + align:start position:0% +commits a a re a really uh uh mean or at + + + align:start position:0% +commits a a re a really uh uh mean or at +least or or or at least unpleasant act + + align:start position:0% +least or or or at least unpleasant act + + + align:start position:0% +least or or or at least unpleasant act +By ignoring his wife's struggles she + + align:start position:0% +By ignoring his wife's struggles she + + + align:start position:0% +By ignoring his wife's struggles she +doesn't even think to complain to him + + align:start position:0% +doesn't even think to complain to him + + + align:start position:0% +doesn't even think to complain to him +about it because she shares his anxiety + + align:start position:0% +about it because she shares his anxiety + + + align:start position:0% +about it because she shares his anxiety +so that's it's an example of what I mean + + align:start position:0% +so that's it's an example of what I mean + + + align:start position:0% +so that's it's an example of what I mean +by a Moment of Multiplicity in which + + align:start position:0% +by a Moment of Multiplicity in which + + + align:start position:0% +by a Moment of Multiplicity in which +something about their relationship + + align:start position:0% +something about their relationship + + + align:start position:0% +something about their relationship +something about their marriage emerges + + align:start position:0% +something about their marriage emerges + + + align:start position:0% +something about their marriage emerges +even as we are also learning something + + align:start position:0% +even as we are also learning something + + + align:start position:0% +even as we are also learning something +about the economic circumstances in + + align:start position:0% +about the economic circumstances in + + + align:start position:0% +about the economic circumstances in +which these characters live say a little + + align:start position:0% +which these characters live say a little + + + align:start position:0% +which these characters live say a little +bit more about the scene that you saw + + align:start position:0% +bit more about the scene that you saw + + + align:start position:0% +bit more about the scene that you saw +how about the place where she's drawing + + align:start position:0% +how about the place where she's drawing + + + align:start position:0% +how about the place where she's drawing +War + + align:start position:0% +War + + + align:start position:0% +War +what about that why would they're in a + + align:start position:0% +what about that why would they're in a + + + align:start position:0% +what about that why would they're in a +city they're they're walking in fact to + + align:start position:0% +city they're they're walking in fact to + + + align:start position:0% +city they're they're walking in fact to +a high-rise apartment house in which + + align:start position:0% +a high-rise apartment house in which + + + align:start position:0% +a high-rise apartment house in which +they live what does it mean that she's + + align:start position:0% +they live what does it mean that she's + + + align:start position:0% +they live what does it mean that she's +carrying two buckets of water to an + + align:start position:0% +carrying two buckets of water to an + + + align:start position:0% +carrying two buckets of water to an +apartment and then she's going to climb + + align:start position:0% +apartment and then she's going to climb + + + align:start position:0% +apartment and then she's going to climb +up four flights or three flights to get + + align:start position:0% +up four flights or three flights to get + + + align:start position:0% +up four flights or three flights to get +to their apartment what does that tell + + align:start position:0% +to their apartment what does that tell + + + align:start position:0% +to their apartment what does that tell +us about melini's Italy there's no + + align:start position:0% +us about melini's Italy there's no + + + align:start position:0% +us about melini's Italy there's no +running water in the building in the in + + align:start position:0% +running water in the building in the in + + + align:start position:0% +running water in the building in the in +the high-rise apartments right uh and + + align:start position:0% +the high-rise apartments right uh and + + + align:start position:0% +the high-rise apartments right uh and +not just that is the water precious how + + align:start position:0% +not just that is the water precious how + + + align:start position:0% +not just that is the water precious how +do you know it is + + align:start position:0% + + + + align:start position:0% + +say yes but what else where do they get + + align:start position:0% +say yes but what else where do they get + + + align:start position:0% +say yes but what else where do they get +the water is the water do they go to a + + align:start position:0% +the water is the water do they go to a + + + align:start position:0% +the water is the water do they go to a +pump in the open Square no it's in a + + align:start position:0% +pump in the open Square no it's in a + + + align:start position:0% +pump in the open Square no it's in a +barbed wire compound right again these + + align:start position:0% +barbed wire compound right again these + + + align:start position:0% +barbed wire compound right again these +details may not register instantly as + + align:start position:0% +details may not register instantly as + + + align:start position:0% +details may not register instantly as +deeply significant but think what they + + align:start position:0% +deeply significant but think what they + + + align:start position:0% +deeply significant but think what they +tell us about the conditions of urban + + align:start position:0% +tell us about the conditions of urban + + + align:start position:0% +tell us about the conditions of urban +life in Rome in 1947 or 1948 when the + + align:start position:0% +life in Rome in 1947 or 1948 when the + + + align:start position:0% +life in Rome in 1947 or 1948 when the +film is when the film is set you have + + align:start position:0% +film is when the film is set you have + + + align:start position:0% +film is when the film is set you have +and and and you could even go further + + align:start position:0% +and and and you could even go further + + + align:start position:0% +and and and you could even go further +look more closely at the setting did + + align:start position:0% +look more closely at the setting did + + + align:start position:0% +look more closely at the setting did +anything grow there it looked like they + + align:start position:0% +anything grow there it looked like they + + + align:start position:0% +anything grow there it looked like they +were walking across across a wasteland + + align:start position:0% +were walking across across a wasteland + + + align:start position:0% +were walking across across a wasteland +of mud except for these high-rise + + align:start position:0% +of mud except for these high-rise + + + align:start position:0% +of mud except for these high-rise +tenement buildings so we have high-rise + + align:start position:0% +tenement buildings so we have high-rise + + + align:start position:0% +tenement buildings so we have high-rise +tenement buildings set down in a kind of + + align:start position:0% +tenement buildings set down in a kind of + + + align:start position:0% +tenement buildings set down in a kind of +desert right uh a place in uh buildings + + align:start position:0% +desert right uh a place in uh buildings + + + align:start position:0% +desert right uh a place in uh buildings +that don't even have running water uh in + + align:start position:0% +that don't even have running water uh in + + + align:start position:0% +that don't even have running water uh in +which in which the main water pump has + + align:start position:0% +which in which the main water pump has + + + align:start position:0% +which in which the main water pump has +to be protected by barbed wire right so + + align:start position:0% +to be protected by barbed wire right so + + + align:start position:0% +to be protected by barbed wire right so +that it's almost as if in this brief + + align:start position:0% +that it's almost as if in this brief + + + align:start position:0% +that it's almost as if in this brief +introduction to the film the whole + + align:start position:0% +introduction to the film the whole + + + align:start position:0% +introduction to the film the whole +socioeconomic environment of the story + + align:start position:0% +socioeconomic environment of the story + + + align:start position:0% +socioeconomic environment of the story +has been established for us without + + align:start position:0% +has been established for us without + + + align:start position:0% +has been established for us without +anyone giving us lectures about it or + + align:start position:0% +anyone giving us lectures about it or + + + align:start position:0% +anyone giving us lectures about it or +calling our attention to it that's what + + align:start position:0% +calling our attention to it that's what + + + align:start position:0% +calling our attention to it that's what +I by multiplicity when the details of + + align:start position:0% +I by multiplicity when the details of + + + align:start position:0% +I by multiplicity when the details of +the film serve character and serve plot + + align:start position:0% +the film serve character and serve plot + + + align:start position:0% +the film serve character and serve plot +and serve our sense of the environment + + align:start position:0% +and serve our sense of the environment + + + align:start position:0% +and serve our sense of the environment +right uh so it's a it's a rich moment + + align:start position:0% +right uh so it's a it's a rich moment + + + align:start position:0% +right uh so it's a it's a rich moment +it's a moment it's a moment of art it's + + align:start position:0% +it's a moment it's a moment of art it's + + + align:start position:0% +it's a moment it's a moment of art it's +a moment of complexity it's a moment of + + align:start position:0% +a moment of complexity it's a moment of + + + align:start position:0% +a moment of complexity it's a moment of +human + + align:start position:0% +human + + + align:start position:0% +human +truthfulness that that resonates for us + + align:start position:0% +truthfulness that that resonates for us + + + align:start position:0% +truthfulness that that resonates for us +as the as the film as the film goes on + + align:start position:0% +as the as the film as the film goes on + + + align:start position:0% +as the as the film as the film goes on +well there are many many moments like + + align:start position:0% +well there are many many moments like + + + align:start position:0% +well there are many many moments like +this virtually every moment uh in + + align:start position:0% +this virtually every moment uh in + + + align:start position:0% +this virtually every moment uh in +bicycle thieves has this kind of density + + align:start position:0% +bicycle thieves has this kind of density + + + align:start position:0% +bicycle thieves has this kind of density +or texture has this kind of uh uh + + align:start position:0% +or texture has this kind of uh uh + + + align:start position:0% +or texture has this kind of uh uh +implication built into the particular + + align:start position:0% +implication built into the particular + + + align:start position:0% +implication built into the particular +details I want to very quickly set the + + align:start position:0% +details I want to very quickly set the + + + align:start position:0% +details I want to very quickly set the +kind of the context for I've already + + align:start position:0% +kind of the context for I've already + + + align:start position:0% +kind of the context for I've already +implied the context for the neorealist + + align:start position:0% +implied the context for the neorealist + + + align:start position:0% +implied the context for the neorealist +movement the basic context is the end of + + align:start position:0% +movement the basic context is the end of + + + align:start position:0% +movement the basic context is the end of +World War II uh most historians trace + + align:start position:0% +World War II uh most historians trace + + + align:start position:0% +World War II uh most historians trace +the beginnings of the neorealist + + align:start position:0% +the beginnings of the neorealist + + + align:start position:0% +the beginnings of the neorealist +movement to to films that were made + + align:start position:0% +movement to to films that were made + + + align:start position:0% +movement to to films that were made +under melini while while while the war + + align:start position:0% +under melini while while while the war + + + align:start position:0% +under melini while while while the war +was still going on and some people + + align:start position:0% +was still going on and some people + + + align:start position:0% +was still going on and some people +actually date the very beginning of + + align:start position:0% +actually date the very beginning of + + + align:start position:0% +actually date the very beginning of +of um the movement to a film made in uh + + align:start position:0% +of um the movement to a film made in uh + + + align:start position:0% +of um the movement to a film made in uh +1942 by luchino Visconti called + + align:start position:0% +1942 by luchino Visconti called + + + align:start position:0% +1942 by luchino Visconti called +Obsession uh it's actually a an + + align:start position:0% +Obsession uh it's actually a an + + + align:start position:0% +Obsession uh it's actually a an +adaptation of a of a a very a popular + + align:start position:0% +adaptation of a of a a very a popular + + + align:start position:0% +adaptation of a of a a very a popular +American pulp novel called The Postman + + align:start position:0% +American pulp novel called The Postman + + + align:start position:0% +American pulp novel called The Postman +Always Rings Twice It's been made twice + + align:start position:0% +Always Rings Twice It's been made twice + + + align:start position:0% +Always Rings Twice It's been made twice +into an English Language American movie + + align:start position:0% +into an English Language American movie + + + align:start position:0% +into an English Language American movie +but most recently starring Jack + + align:start position:0% +but most recently starring Jack + + + align:start position:0% +but most recently starring Jack +Nicholson uh the but but but the the + + align:start position:0% +Nicholson uh the but but but the the + + + align:start position:0% +Nicholson uh the but but but the the +Italian version may be the most the most + + align:start position:0% +Italian version may be the most the most + + + align:start position:0% +Italian version may be the most the most +important and interesting of the uh + + align:start position:0% +important and interesting of the uh + + + align:start position:0% +important and interesting of the uh +films made from the book uh the the the + + align:start position:0% +films made from the book uh the the the + + + align:start position:0% +films made from the book uh the the the +book itself is a rather tody uh noirish + + align:start position:0% +book itself is a rather tody uh noirish + + + align:start position:0% +book itself is a rather tody uh noirish +story about about a uh the owner of a + + align:start position:0% +story about about a uh the owner of a + + + align:start position:0% +story about about a uh the owner of a +diner who's + + align:start position:0% +diner who's + + + align:start position:0% +diner who's +who an ugly middle-aged pug who's + + align:start position:0% +who an ugly middle-aged pug who's + + + align:start position:0% +who an ugly middle-aged pug who's +married to a beautiful and somewhat + + align:start position:0% +married to a beautiful and somewhat + + + align:start position:0% +married to a beautiful and somewhat +younger woman who very unhappy with her + + align:start position:0% +younger woman who very unhappy with her + + + align:start position:0% +younger woman who very unhappy with her +husband uh uh begins an affair with a + + align:start position:0% +husband uh uh begins an affair with a + + + align:start position:0% +husband uh uh begins an affair with a +Drifter who comes by and uh um + + align:start position:0% +Drifter who comes by and uh um + + + align:start position:0% +Drifter who comes by and uh um +ultimately encourages The Drifter to + + align:start position:0% +ultimately encourages The Drifter to + + + align:start position:0% +ultimately encourages The Drifter to +kill her husband uh and it's a it's + + align:start position:0% +kill her husband uh and it's a it's + + + align:start position:0% +kill her husband uh and it's a it's +actually a rather uh a rather + + align:start position:0% +actually a rather uh a rather + + + align:start position:0% +actually a rather uh a rather +heavy-handed uh male chauvinist fantasy + + align:start position:0% +heavy-handed uh male chauvinist fantasy + + + align:start position:0% +heavy-handed uh male chauvinist fantasy +about uh about the partly about about + + align:start position:0% +about uh about the partly about about + + + align:start position:0% +about uh about the partly about about +how cunning and dangerous women are the + + align:start position:0% +how cunning and dangerous women are the + + + align:start position:0% +how cunning and dangerous women are the +Italian version is much more interesting + + align:start position:0% +Italian version is much more interesting + + + align:start position:0% +Italian version is much more interesting +in part because the workingclass + + align:start position:0% +in part because the workingclass + + + align:start position:0% +in part because the workingclass +dimensions of the story are given much + + align:start position:0% +dimensions of the story are given much + + + align:start position:0% +dimensions of the story are given much +greater emphasis in Lino Visconti's + + align:start position:0% +greater emphasis in Lino Visconti's + + + align:start position:0% +greater emphasis in Lino Visconti's +version and the film partly becomes a + + align:start position:0% +version and the film partly becomes a + + + align:start position:0% +version and the film partly becomes a +kind of meditation on the fate of uh + + align:start position:0% +kind of meditation on the fate of uh + + + align:start position:0% +kind of meditation on the fate of uh +undocumented workers and non-union + + align:start position:0% +undocumented workers and non-union + + + align:start position:0% +undocumented workers and non-union +workers in in uh uh in in uh uh Italian + + align:start position:0% +workers in in uh uh in in uh uh Italian + + + align:start position:0% +workers in in uh uh in in uh uh Italian +Society uh in any case the emphasis on + + align:start position:0% +Society uh in any case the emphasis on + + + align:start position:0% +Society uh in any case the emphasis on +ordinary people and the emphasis on + + align:start position:0% +ordinary people and the emphasis on + + + align:start position:0% +ordinary people and the emphasis on +socioeconomic circumstances in that film + + align:start position:0% +socioeconomic circumstances in that film + + + align:start position:0% +socioeconomic circumstances in that film +by visanti came to be defining features + + align:start position:0% +by visanti came to be defining features + + + align:start position:0% +by visanti came to be defining features +among the defining features of Italian + + align:start position:0% +among the defining features of Italian + + + align:start position:0% +among the defining features of Italian +neorealist um uh film + + align:start position:0% +neorealist um uh film + + + align:start position:0% +neorealist um uh film +making but the movement really doesn't + + align:start position:0% +making but the movement really doesn't + + + align:start position:0% +making but the movement really doesn't +get going until after the war and the + + align:start position:0% +get going until after the war and the + + + align:start position:0% +get going until after the war and the +context of the war is very important we + + align:start position:0% +context of the war is very important we + + + align:start position:0% +context of the war is very important we +need to recognize that the film is + + align:start position:0% +need to recognize that the film is + + + align:start position:0% +need to recognize that the film is +really set in a devastated Society a + + align:start position:0% +really set in a devastated Society a + + + align:start position:0% +really set in a devastated Society a +society uh in which I'm talking now + + align:start position:0% +society uh in which I'm talking now + + + align:start position:0% +society uh in which I'm talking now +about all of Europe after the second + + align:start position:0% +about all of Europe after the second + + + align:start position:0% +about all of Europe after the second +world war unemployment reached at 25 or + + align:start position:0% +world war unemployment reached at 25 or + + + align:start position:0% +world war unemployment reached at 25 or +30% higher in some societies uh there + + align:start position:0% +30% higher in some societies uh there + + + align:start position:0% +30% higher in some societies uh there +was economic turmoil in virtually every + + align:start position:0% +was economic turmoil in virtually every + + + align:start position:0% +was economic turmoil in virtually every +European Society profound terrible + + align:start position:0% +European Society profound terrible + + + align:start position:0% +European Society profound terrible +pressures from Black Market um uh + + align:start position:0% +pressures from Black Market um uh + + + align:start position:0% +pressures from Black Market um uh +activities of all kinds the de the war + + align:start position:0% +activities of all kinds the de the war + + + align:start position:0% +activities of all kinds the de the war +was so devast stating that something on + + align:start position:0% +was so devast stating that something on + + + align:start position:0% +was so devast stating that something on +the order of 35% of all the permanent + + align:start position:0% +the order of 35% of all the permanent + + + align:start position:0% +the order of 35% of all the permanent +dwellings in Western Europe were + + align:start position:0% +dwellings in Western Europe were + + + align:start position:0% +dwellings in Western Europe were +destroyed during the War uh 25% of the + + align:start position:0% +destroyed during the War uh 25% of the + + + align:start position:0% +destroyed during the War uh 25% of the +Polish population was killed a + + align:start position:0% +Polish population was killed a + + + align:start position:0% +Polish population was killed a +tremendous proportion uh virtually every + + align:start position:0% +tremendous proportion uh virtually every + + + align:start position:0% +tremendous proportion uh virtually every +well a very large number of Italian + + align:start position:0% +well a very large number of Italian + + + align:start position:0% +well a very large number of Italian +cities were damaged very badly including + + align:start position:0% +cities were damaged very badly including + + + align:start position:0% +cities were damaged very badly including +of course Rome itself uh and and these + + align:start position:0% +of course Rome itself uh and and these + + + align:start position:0% +of course Rome itself uh and and these +these abject and terrifying economic + + align:start position:0% +these abject and terrifying economic + + + align:start position:0% +these abject and terrifying economic +conditions were were of course uh in in + + align:start position:0% +conditions were were of course uh in in + + + align:start position:0% +conditions were were of course uh in in +Italy doubled by the problem that Italy + + align:start position:0% +Italy doubled by the problem that Italy + + + align:start position:0% +Italy doubled by the problem that Italy +was on the losing side in the war and + + align:start position:0% +was on the losing side in the war and + + + align:start position:0% +was on the losing side in the war and +had and and uh + + align:start position:0% +had and and uh + + + align:start position:0% +had and and uh +therefore faced even more difficulties + + align:start position:0% +therefore faced even more difficulties + + + align:start position:0% +therefore faced even more difficulties +in in in a Rec in the recovery than than + + align:start position:0% +in in in a Rec in the recovery than than + + + align:start position:0% +in in in a Rec in the recovery than than +uh a culture like the French culture or + + align:start position:0% +uh a culture like the French culture or + + + align:start position:0% +uh a culture like the French culture or +the or or or or English society so so + + align:start position:0% +the or or or or English society so so + + + align:start position:0% +the or or or or English society so so +the devastation of World War II and the + + align:start position:0% +the devastation of World War II and the + + + align:start position:0% +the devastation of World War II and the +turmoil and and and dislocation caused + + align:start position:0% +turmoil and and and dislocation caused + + + align:start position:0% +turmoil and and and dislocation caused +by World War II is the fundamental fact + + align:start position:0% +by World War II is the fundamental fact + + + align:start position:0% +by World War II is the fundamental fact +in words what what is still operative in + + align:start position:0% +in words what what is still operative in + + + align:start position:0% +in words what what is still operative in +Italian Society what institutions still + + align:start position:0% +Italian Society what institutions still + + + align:start position:0% +Italian Society what institutions still +work is one of the implicit questions + + align:start position:0% +work is one of the implicit questions + + + align:start position:0% +work is one of the implicit questions +that the film explores and the film + + align:start position:0% +that the film explores and the film + + + align:start position:0% +that the film explores and the film +suggests that a lot of the official + + align:start position:0% +suggests that a lot of the official + + + align:start position:0% +suggests that a lot of the official +institutions like the police and the and + + align:start position:0% +institutions like the police and the and + + + align:start position:0% +institutions like the police and the and +the and and especially the religious + + align:start position:0% +the and and especially the religious + + + align:start position:0% +the and and especially the religious +institutions have broken down and are + + align:start position:0% +institutions have broken down and are + + + align:start position:0% +institutions have broken down and are +not really helping people very much as + + align:start position:0% +not really helping people very much as + + + align:start position:0% +not really helping people very much as +you'll see when you when you watch + + align:start position:0% +you'll see when you when you watch + + + align:start position:0% +you'll see when you when you watch +tonight's film but that there there are + + align:start position:0% +tonight's film but that there there are + + + align:start position:0% +tonight's film but that there there are +other uh forms + + align:start position:0% +other uh forms + + + align:start position:0% +other uh forms +of help and Aid that people get mostly + + align:start position:0% +of help and Aid that people get mostly + + + align:start position:0% +of help and Aid that people get mostly +in some sense from their the film + + align:start position:0% +in some sense from their the film + + + align:start position:0% +in some sense from their the film +suggests from their local communities + + align:start position:0% +suggests from their local communities + + + align:start position:0% +suggests from their local communities +and from their and from and from their + + align:start position:0% +and from their and from and from their + + + align:start position:0% +and from their and from and from their +immediate families well to this basic + + align:start position:0% +immediate families well to this basic + + + align:start position:0% +immediate families well to this basic +sort of setting of Devastation and + + align:start position:0% +sort of setting of Devastation and + + + align:start position:0% +sort of setting of Devastation and +turmoil and un and economic uncertainty + + align:start position:0% +turmoil and un and economic uncertainty + + + align:start position:0% +turmoil and un and economic uncertainty +we need we need to add two other + + align:start position:0% +we need we need to add two other + + + align:start position:0% +we need we need to add two other +contextual + + align:start position:0% +contextual + + + align:start position:0% +contextual +factors both of them having to do with + + align:start position:0% +factors both of them having to do with + + + align:start position:0% +factors both of them having to do with +the film Traditions against which + + align:start position:0% +the film Traditions against which + + + align:start position:0% +the film Traditions against which +neorealism set itself against which it + + align:start position:0% +neorealism set itself against which it + + + align:start position:0% +neorealism set itself against which it +understood itself to be ar uh to be um + + align:start position:0% +understood itself to be ar uh to be um + + + align:start position:0% +understood itself to be ar uh to be um +uh in in in a in a kind of profound + + align:start position:0% +uh in in in a in a kind of profound + + + align:start position:0% +uh in in in a in a kind of profound +argument the first tradition was the + + align:start position:0% +argument the first tradition was the + + + align:start position:0% +argument the first tradition was the +tradition of of fascist film under + + align:start position:0% +tradition of of fascist film under + + + align:start position:0% +tradition of of fascist film under +melini + + align:start position:0% +melini + + + align:start position:0% +melini +these were very almost all Studio films + + align:start position:0% +these were very almost all Studio films + + + align:start position:0% +these were very almost all Studio films +they were shot inside Studios neorealist + + align:start position:0% +they were shot inside Studios neorealist + + + align:start position:0% +they were shot inside Studios neorealist +films are shot + + align:start position:0% +films are shot + + + align:start position:0% +films are shot +outdoors and they all and they were + + align:start position:0% +outdoors and they all and they were + + + align:start position:0% +outdoors and they all and they were +largely Escapist uh they were largely + + align:start position:0% +largely Escapist uh they were largely + + + align:start position:0% +largely Escapist uh they were largely +Escapist Fair uh focusing more often + + align:start position:0% +Escapist Fair uh focusing more often + + + align:start position:0% +Escapist Fair uh focusing more often +than not on the upper social orders in + + align:start position:0% +than not on the upper social orders in + + + align:start position:0% +than not on the upper social orders in +fact there was a genre of film so + + align:start position:0% +fact there was a genre of film so + + + align:start position:0% +fact there was a genre of film so +devoted to the Romantic entanglements of + + align:start position:0% +devoted to the Romantic entanglements of + + + align:start position:0% +devoted to the Romantic entanglements of +aristocrats that they came to be known + + align:start position:0% +aristocrats that they came to be known + + + align:start position:0% +aristocrats that they came to be known +as white telephone films the reason for + + align:start position:0% +as white telephone films the reason for + + + align:start position:0% +as white telephone films the reason for +this is that in the old days before cell + + align:start position:0% +this is that in the old days before cell + + + align:start position:0% +this is that in the old days before cell +phones uh and before multicolored phones + + align:start position:0% +phones uh and before multicolored phones + + + align:start position:0% +phones uh and before multicolored phones +all telephones were + + align:start position:0% +all telephones were + + + align:start position:0% +all telephones were +black uh and uh it was a mark of + + align:start position:0% +black uh and uh it was a mark of + + + align:start position:0% +black uh and uh it was a mark of +astonishing + + align:start position:0% +astonishing + + + align:start position:0% +astonishing +aristocratic privilege that the people + + align:start position:0% +aristocratic privilege that the people + + + align:start position:0% +aristocratic privilege that the people +in some of these films had white + + align:start position:0% +in some of these films had white + + + align:start position:0% +in some of these films had white +telephones they were such unusual + + align:start position:0% +telephones they were such unusual + + + align:start position:0% +telephones they were such unusual +objects for the time that the films came + + align:start position:0% +objects for the time that the films came + + + align:start position:0% +objects for the time that the films came +to be labeled as white telephone films + + align:start position:0% +to be labeled as white telephone films + + + align:start position:0% +to be labeled as white telephone films +and they were largely uh as I said + + align:start position:0% +and they were largely uh as I said + + + align:start position:0% +and they were largely uh as I said +Escapist movies with with beautifully + + align:start position:0% +Escapist movies with with beautifully + + + align:start position:0% +Escapist movies with with beautifully +made up uh actors and actresses in + + align:start position:0% +made up uh actors and actresses in + + + align:start position:0% +made up uh actors and actresses in +artificial light per forming what were + + align:start position:0% +artificial light per forming what were + + + align:start position:0% +artificial light per forming what were +essentially artificial Stories the + + align:start position:0% +essentially artificial Stories the + + + align:start position:0% +essentially artificial Stories the +second tradition against which the + + align:start position:0% +second tradition against which the + + + align:start position:0% +second tradition against which the +neorealists are responding against which + + align:start position:0% +neorealists are responding against which + + + align:start position:0% +neorealists are responding against which +they are reacting is the tradition of + + align:start position:0% +they are reacting is the tradition of + + + align:start position:0% +they are reacting is the tradition of +Hollywood glamour there's a wonderful + + align:start position:0% +Hollywood glamour there's a wonderful + + + align:start position:0% +Hollywood glamour there's a wonderful +moment in The Bicycle Thief and you'll + + align:start position:0% +moment in The Bicycle Thief and you'll + + + align:start position:0% +moment in The Bicycle Thief and you'll +as you'll see tonight when Richi finally + + align:start position:0% +as you'll see tonight when Richi finally + + + align:start position:0% +as you'll see tonight when Richi finally +goes off to get his job he recovers his + + align:start position:0% +goes off to get his job he recovers his + + + align:start position:0% +goes off to get his job he recovers his +bicycle from hackets he he's pawned it + + align:start position:0% +bicycle from hackets he he's pawned it + + + align:start position:0% +bicycle from hackets he he's pawned it +uh and that's why he's so nervous he + + align:start position:0% +uh and that's why he's so nervous he + + + align:start position:0% +uh and that's why he's so nervous he +knows where the bicycle is but he + + align:start position:0% +knows where the bicycle is but he + + + align:start position:0% +knows where the bicycle is but he +doesn't know how they're going to get it + + align:start position:0% +doesn't know how they're going to get it + + + align:start position:0% +doesn't know how they're going to get it +out of Pawn and you'll see how his wife + + align:start position:0% +out of Pawn and you'll see how his wife + + + align:start position:0% +out of Pawn and you'll see how his wife +solves that problem in the very next + + align:start position:0% +solves that problem in the very next + + + align:start position:0% +solves that problem in the very next +sequence is Bey uh beyond the one I've + + align:start position:0% +sequence is Bey uh beyond the one I've + + + align:start position:0% +sequence is Bey uh beyond the one I've +just shown to you um when Richi finally + + align:start position:0% +just shown to you um when Richi finally + + + align:start position:0% +just shown to you um when Richi finally +goes to work for the first time he has + + align:start position:0% +goes to work for the first time he has + + + align:start position:0% +goes to work for the first time he has +someone with him giving him instructions + + align:start position:0% +someone with him giving him instructions + + + align:start position:0% +someone with him giving him instructions +and what he is is a bill sticker he puts + + align:start position:0% +and what he is is a bill sticker he puts + + + align:start position:0% +and what he is is a bill sticker he puts +up posters great Po in fact the poster + + align:start position:0% +up posters great Po in fact the poster + + + align:start position:0% +up posters great Po in fact the poster +that he's putting up is a poster for an + + align:start position:0% +that he's putting up is a poster for an + + + align:start position:0% +that he's putting up is a poster for an +American movie and it has a great am + + align:start position:0% +American movie and it has a great am + + + align:start position:0% +American movie and it has a great am +famous American movie star of the 40s + + align:start position:0% +famous American movie star of the 40s + + + align:start position:0% +famous American movie star of the 40s +and 50s Rita Hayworth on the on it and + + align:start position:0% +and 50s Rita Hayworth on the on it and + + + align:start position:0% +and 50s Rita Hayworth on the on it and +as he's putting the picture up he uh you + + align:start position:0% +as he's putting the picture up he uh you + + + align:start position:0% +as he's putting the picture up he uh you +put paste on the board then you he's + + align:start position:0% +put paste on the board then you he's + + + align:start position:0% +put paste on the board then you he's +given the stupid instructions anyone + + align:start position:0% +given the stupid instructions anyone + + + align:start position:0% +given the stupid instructions anyone +could do this job but the man giving him + + align:start position:0% +could do this job but the man giving him + + + align:start position:0% +could do this job but the man giving him +instructions acts as if he's explaining + + align:start position:0% +instructions acts as if he's explaining + + + align:start position:0% +instructions acts as if he's explaining +something really difficult + + align:start position:0% +something really difficult + + + align:start position:0% +something really difficult +like like rocket science uh when all + + align:start position:0% +like like rocket science uh when all + + + align:start position:0% +like like rocket science uh when all +he's doing is tell telling him how to + + align:start position:0% +he's doing is tell telling him how to + + + align:start position:0% +he's doing is tell telling him how to +paste a a poster up on a board but his + + align:start position:0% +paste a a poster up on a board but his + + + align:start position:0% +paste a a poster up on a board but his +but his instructions include a + + align:start position:0% +but his instructions include a + + + align:start position:0% +but his instructions include a +systematic uh remarks about being sure + + align:start position:0% +systematic uh remarks about being sure + + + align:start position:0% +systematic uh remarks about being sure +not to leave any wrinkles in it and I've + + align:start position:0% +not to leave any wrinkles in it and I've + + + align:start position:0% +not to leave any wrinkles in it and I've +taken that myself to be a kind of + + align:start position:0% +taken that myself to be a kind of + + + align:start position:0% +taken that myself to be a kind of +implicit complaint against Hollywood + + align:start position:0% +implicit complaint against Hollywood + + + align:start position:0% +implicit complaint against Hollywood +that say the Hollywood the Hollywood + + align:start position:0% +that say the Hollywood the Hollywood + + + align:start position:0% +that say the Hollywood the Hollywood +female has no wrinkles the Hollywood + + align:start position:0% +female has no wrinkles the Hollywood + + + align:start position:0% +female has no wrinkles the Hollywood +female uh the Hollywood star the + + align:start position:0% +female uh the Hollywood star the + + + align:start position:0% +female uh the Hollywood star the +Hollywood movie is so glamorized that + + align:start position:0% +Hollywood movie is so glamorized that + + + align:start position:0% +Hollywood movie is so glamorized that +you never see wrinkles or defects and + + align:start position:0% +you never see wrinkles or defects and + + + align:start position:0% +you never see wrinkles or defects and +this couldn't contrast more sharply with + + align:start position:0% +this couldn't contrast more sharply with + + + align:start position:0% +this couldn't contrast more sharply with +the ordinary faces of the actors that we + + align:start position:0% +the ordinary faces of the actors that we + + + align:start position:0% +the ordinary faces of the actors that we +see in neorealist films so two + + align:start position:0% +see in neorealist films so two + + + align:start position:0% +see in neorealist films so two +traditions of Glamour and of and of + + align:start position:0% +traditions of Glamour and of and of + + + align:start position:0% +traditions of Glamour and of and of +escapism are essentially uh the + + align:start position:0% +escapism are essentially uh the + + + align:start position:0% +escapism are essentially uh the +antagonists that that uh that that that + + align:start position:0% +antagonists that that uh that that that + + + align:start position:0% +antagonists that that uh that that that +that that help to explain how neorealism + + align:start position:0% +that that help to explain how neorealism + + + align:start position:0% +that that help to explain how neorealism +defines itself uh uh and under and + + align:start position:0% +defines itself uh uh and under and + + + align:start position:0% +defines itself uh uh and under and +understands itself it's worth briefly + + align:start position:0% +understands itself it's worth briefly + + + align:start position:0% +understands itself it's worth briefly +mentioning that neorealism has + + align:start position:0% +mentioning that neorealism has + + + align:start position:0% +mentioning that neorealism has +distinguished Origins uh in at least + + align:start position:0% +distinguished Origins uh in at least + + + align:start position:0% +distinguished Origins uh in at least +three different National Cinemas the + + align:start position:0% +three different National Cinemas the + + + align:start position:0% +three different National Cinemas the +first is in Italian Cinema itself um uh + + align:start position:0% +first is in Italian Cinema itself um uh + + + align:start position:0% +first is in Italian Cinema itself um uh +there was a movement in during the + + align:start position:0% +there was a movement in during the + + + align:start position:0% +there was a movement in during the +silent era a kind of documentary + + align:start position:0% +silent era a kind of documentary + + + align:start position:0% +silent era a kind of documentary +movement that wanted to talk a quazi + + align:start position:0% +movement that wanted to talk a quazi + + + align:start position:0% +movement that wanted to talk a quazi +documentary movement they were still + + align:start position:0% +documentary movement they were still + + + align:start position:0% +documentary movement they were still +fiction films but they wanted to talk + + align:start position:0% +fiction films but they wanted to talk + + + align:start position:0% +fiction films but they wanted to talk +more openly and honestly about + + align:start position:0% +more openly and honestly about + + + align:start position:0% +more openly and honestly about +contemporary events and contemporary + + align:start position:0% +contemporary events and contemporary + + + align:start position:0% +contemporary events and contemporary +Society and the movement was called the + + align:start position:0% +Society and the movement was called the + + + align:start position:0% +Society and the movement was called the +Verismo movement the truth movement + + align:start position:0% +Verismo movement the truth movement + + + align:start position:0% +Verismo movement the truth movement +right and it occurred between 1914 and + + align:start position:0% +right and it occurred between 1914 and + + + align:start position:0% +right and it occurred between 1914 and +1916 in Italy and this and when the Neo + + align:start position:0% +1916 in Italy and this and when the Neo + + + align:start position:0% +1916 in Italy and this and when the Neo +when when the neorealists began to + + align:start position:0% +when when the neorealists began to + + + align:start position:0% +when when the neorealists began to +articulate their own manifestos and to + + align:start position:0% +articulate their own manifestos and to + + + align:start position:0% +articulate their own manifestos and to +explain theoretically what they were up + + align:start position:0% +explain theoretically what they were up + + + align:start position:0% +explain theoretically what they were up +to they sometimes reached back to the + + align:start position:0% +to they sometimes reached back to the + + + align:start position:0% +to they sometimes reached back to the +Verismo movement as a way of saying + + align:start position:0% +Verismo movement as a way of saying + + + align:start position:0% +Verismo movement as a way of saying +we're we're actually traditional as well + + align:start position:0% +we're we're actually traditional as well + + + align:start position:0% +we're we're actually traditional as well +as new a second fundamental influence on + + align:start position:0% +as new a second fundamental influence on + + + align:start position:0% +as new a second fundamental influence on +neorealism uh a kind of earlier version + + align:start position:0% +neorealism uh a kind of earlier version + + + align:start position:0% +neorealism uh a kind of earlier version +of neorealism occurred in the German + + align:start position:0% +of neorealism occurred in the German + + + align:start position:0% +of neorealism occurred in the German +Tradition at the end of the silent era + + align:start position:0% +Tradition at the end of the silent era + + + align:start position:0% +Tradition at the end of the silent era +in a series of films made in the 1920s + + align:start position:0% +in a series of films made in the 1920s + + + align:start position:0% +in a series of films made in the 1920s +by the director GW Pap + + align:start position:0% +by the director GW Pap + + + align:start position:0% +by the director GW Pap +PST his the most famous of these films + + align:start position:0% +PST his the most famous of these films + + + align:start position:0% +PST his the most famous of these films +is a film produced in 1925 called the + + align:start position:0% +is a film produced in 1925 called the + + + align:start position:0% +is a film produced in 1925 called the +joyless street and partly deals with + + align:start position:0% +joyless street and partly deals with + + + align:start position:0% +joyless street and partly deals with +prostitutes and it and it and it talks + + align:start position:0% +prostitutes and it and it and it talks + + + align:start position:0% +prostitutes and it and it and it talks +in it tries to dramatize in realistic + + align:start position:0% +in it tries to dramatize in realistic + + + align:start position:0% +in it tries to dramatize in realistic +ways the conditions of the lower social + + align:start position:0% +ways the conditions of the lower social + + + align:start position:0% +ways the conditions of the lower social +orders uh and of course the final um + + align:start position:0% +orders uh and of course the final um + + + align:start position:0% +orders uh and of course the final um +originating Source this also so explains + + align:start position:0% +originating Source this also so explains + + + align:start position:0% +originating Source this also so explains +the richness of neorealism that there + + align:start position:0% +the richness of neorealism that there + + + align:start position:0% +the richness of neorealism that there +are these other film Traditions that are + + align:start position:0% +are these other film Traditions that are + + + align:start position:0% +are these other film Traditions that are +feeding into it and enriching it uh is + + align:start position:0% +feeding into it and enriching it uh is + + + align:start position:0% +feeding into it and enriching it uh is +French and it's the it's the kind of + + align:start position:0% +French and it's the it's the kind of + + + align:start position:0% +French and it's the it's the kind of +French film that we associate with Jean + + align:start position:0% +French film that we associate with Jean + + + align:start position:0% +French film that we associate with Jean +Renoir and with the traditions of poetic + + align:start position:0% +Renoir and with the traditions of poetic + + + align:start position:0% +Renoir and with the traditions of poetic +realism uh uh some of the neorealist one + + align:start position:0% +realism uh uh some of the neorealist one + + + align:start position:0% +realism uh uh some of the neorealist one +of at least one of the neorealist + + align:start position:0% +of at least one of the neorealist + + + align:start position:0% +of at least one of the neorealist +directors visconte had worked as an + + align:start position:0% +directors visconte had worked as an + + + align:start position:0% +directors visconte had worked as an +assistant director for Jean Renoir at + + align:start position:0% +assistant director for Jean Renoir at + + + align:start position:0% +assistant director for Jean Renoir at +one point in his career and uh I I + + align:start position:0% +one point in his career and uh I I + + + align:start position:0% +one point in his career and uh I I +believe I'm not sure this is accurate so + + align:start position:0% +believe I'm not sure this is accurate so + + + align:start position:0% +believe I'm not sure this is accurate so +don't take this as absolute fact but I + + align:start position:0% +don't take this as absolute fact but I + + + align:start position:0% +don't take this as absolute fact but I +believe that it was Renoir himself who + + align:start position:0% +believe that it was Renoir himself who + + + align:start position:0% +believe that it was Renoir himself who +gave a copy of The Postman Always Rings + + align:start position:0% +gave a copy of The Postman Always Rings + + + align:start position:0% +gave a copy of The Postman Always Rings +Twice to visconte uh to uh which led to + + align:start position:0% +Twice to visconte uh to uh which led to + + + align:start position:0% +Twice to visconte uh to uh which led to +the creation of what many people would + + align:start position:0% +the creation of what many people would + + + align:start position:0% +the creation of what many people would +identify as the very first + + align:start position:0% +identify as the very first + + + align:start position:0% +identify as the very first +neorealist neorealist film the Basic + + align:start position:0% +neorealist neorealist film the Basic + + + align:start position:0% +neorealist neorealist film the Basic +practices and traditions of poetic + + align:start position:0% +practices and traditions of poetic + + + align:start position:0% +practices and traditions of poetic +realism are carried over in neorealism + + align:start position:0% +realism are carried over in neorealism + + + align:start position:0% +realism are carried over in neorealism +and in one sense one can see neorealism + + align:start position:0% +and in one sense one can see neorealism + + + align:start position:0% +and in one sense one can see neorealism +as an extension of poetic realism the + + align:start position:0% +as an extension of poetic realism the + + + align:start position:0% +as an extension of poetic realism the +difference is that neorealism has a more + + align:start position:0% +difference is that neorealism has a more + + + align:start position:0% +difference is that neorealism has a more +political and social orientation it's + + align:start position:0% +political and social orientation it's + + + align:start position:0% +political and social orientation it's +more conscious of having a political and + + align:start position:0% +more conscious of having a political and + + + align:start position:0% +more conscious of having a political and +social ambition it wants to + + align:start position:0% +social ambition it wants to + + + align:start position:0% +social ambition it wants to +uh uh and and and sometimes neorealist + + align:start position:0% +uh uh and and and sometimes neorealist + + + align:start position:0% +uh uh and and and sometimes neorealist +films can seem a bit preachy because of + + align:start position:0% +films can seem a bit preachy because of + + + align:start position:0% +films can seem a bit preachy because of +that I mean there's a there's clearly a + + align:start position:0% +that I mean there's a there's clearly a + + + align:start position:0% +that I mean there's a there's clearly a +kind of a a sentiment uh de deeply + + align:start position:0% +kind of a a sentiment uh de deeply + + + align:start position:0% +kind of a a sentiment uh de deeply +sympathetic to the lower social orders + + align:start position:0% +sympathetic to the lower social orders + + + align:start position:0% +sympathetic to the lower social orders +deeply suspicious of the hierarchies of + + align:start position:0% +deeply suspicious of the hierarchies of + + + align:start position:0% +deeply suspicious of the hierarchies of +capitalism some some of the neorealists + + align:start position:0% +capitalism some some of the neorealists + + + align:start position:0% +capitalism some some of the neorealists +were marxists or Marxist sympathizers uh + + align:start position:0% +were marxists or Marxist sympathizers uh + + + align:start position:0% +were marxists or Marxist sympathizers uh +and that helps to explain the political + + align:start position:0% +and that helps to explain the political + + + align:start position:0% +and that helps to explain the political +orientation of neorealist films but the + + align:start position:0% +orientation of neorealist films but the + + + align:start position:0% +orientation of neorealist films but the +basic features of poetic realism the use + + align:start position:0% +basic features of poetic realism the use + + + align:start position:0% +basic features of poetic realism the use +of an outdoor camera the interest in + + align:start position:0% +of an outdoor camera the interest in + + + align:start position:0% +of an outdoor camera the interest in +aanen + + align:start position:0% +aanen + + + align:start position:0% +aanen +style uh and in a film made by which I + + align:start position:0% +style uh and in a film made by which I + + + align:start position:0% +style uh and in a film made by which I +mentioned I think last time made by + + align:start position:0% +mentioned I think last time made by + + + align:start position:0% +mentioned I think last time made by +Renoir in 1935 a film called Tony T we + + align:start position:0% +Renoir in 1935 a film called Tony T we + + + align:start position:0% +Renoir in 1935 a film called Tony T we +have a French version of neorealism + + align:start position:0% +have a French version of neorealism + + + align:start position:0% +have a French version of neorealism +because that film as I mentioned last + + align:start position:0% +because that film as I mentioned last + + + align:start position:0% +because that film as I mentioned last +time is about Italian Quarry workers in + + align:start position:0% +time is about Italian Quarry workers in + + + align:start position:0% +time is about Italian Quarry workers in +the south of France and it has a lot of + + align:start position:0% +the south of France and it has a lot of + + + align:start position:0% +the south of France and it has a lot of +nonprofessional actors in it something + + align:start position:0% +nonprofessional actors in it something + + + align:start position:0% +nonprofessional actors in it something +that became a key feature of neorealism + + align:start position:0% +that became a key feature of neorealism + + + align:start position:0% +that became a key feature of neorealism +so the neorealist movement then uh has + + align:start position:0% +so the neorealist movement then uh has + + + align:start position:0% +so the neorealist movement then uh has +this powerful context which creates a + + align:start position:0% +this powerful context which creates a + + + align:start position:0% +this powerful context which creates a +kind of moral and and and aesthetic + + align:start position:0% +kind of moral and and and aesthetic + + + align:start position:0% +kind of moral and and and aesthetic +energy that helps to explain the power + + align:start position:0% +energy that helps to explain the power + + + align:start position:0% +energy that helps to explain the power +and the excitement of these films uh it + + align:start position:0% +and the excitement of these films uh it + + + align:start position:0% +and the excitement of these films uh it +has two very clear antagonists the + + align:start position:0% +has two very clear antagonists the + + + align:start position:0% +has two very clear antagonists the +glamour of Hollywood and the the false + + align:start position:0% +glamour of Hollywood and the the false + + + align:start position:0% +glamour of Hollywood and the the false +and aristocratic glamour of the film + + align:start position:0% +and aristocratic glamour of the film + + + align:start position:0% +and aristocratic glamour of the film +under musolini uh and it also draws as + + align:start position:0% +under musolini uh and it also draws as + + + align:start position:0% +under musolini uh and it also draws as +well on older traditions of film in + + align:start position:0% +well on older traditions of film in + + + align:start position:0% +well on older traditions of film in +Italian in German and in French that set + + align:start position:0% +Italian in German and in French that set + + + align:start position:0% +Italian in German and in French that set +earlier examples for the kind of thing + + align:start position:0% +earlier examples for the kind of thing + + + align:start position:0% +earlier examples for the kind of thing +that the neorealists want to do I've + + align:start position:0% +that the neorealists want to do I've + + + align:start position:0% +that the neorealists want to do I've +already talked about the key features of + + align:start position:0% +already talked about the key features of + + + align:start position:0% +already talked about the key features of +neorealism when I uh uh just a second + + align:start position:0% +neorealism when I uh uh just a second + + + align:start position:0% +neorealism when I uh uh just a second +ago when I spoke about poetic realism + + align:start position:0% +ago when I spoke about poetic realism + + + align:start position:0% +ago when I spoke about poetic realism +but let me mention some of those key + + align:start position:0% +but let me mention some of those key + + + align:start position:0% +but let me mention some of those key +features in a little bit more detail one + + align:start position:0% +features in a little bit more detail one + + + align:start position:0% +features in a little bit more detail one +way to think about neorealist films is + + align:start position:0% +way to think about neorealist films is + + + align:start position:0% +way to think about neorealist films is +to recognize that their emphasis on + + align:start position:0% +to recognize that their emphasis on + + + align:start position:0% +to recognize that their emphasis on +reality is one which insists on trying + + align:start position:0% +reality is one which insists on trying + + + align:start position:0% +reality is one which insists on trying +to create uh an illusion of plaus of a + + align:start position:0% +to create uh an illusion of plaus of a + + + align:start position:0% +to create uh an illusion of plaus of a +plausible actuality and what this meant + + align:start position:0% +plausible actuality and what this meant + + + align:start position:0% +plausible actuality and what this meant +to them was listen people have warts on + + align:start position:0% +to them was listen people have warts on + + + align:start position:0% +to them was listen people have warts on +their noses people are not beautiful the + + align:start position:0% +their noses people are not beautiful the + + + align:start position:0% +their noses people are not beautiful the +way they are in Hollywood let so one + + align:start position:0% +way they are in Hollywood let so one + + + align:start position:0% +way they are in Hollywood let so one +thing we need to do is we need to + + align:start position:0% +thing we need to do is we need to + + + align:start position:0% +thing we need to do is we need to +roughen up the look of our performers + + align:start position:0% +roughen up the look of our performers + + + align:start position:0% +roughen up the look of our performers +and in fact professional actors it was + + align:start position:0% +and in fact professional actors it was + + + align:start position:0% +and in fact professional actors it was +felt often bring a kind of smoothness or + + align:start position:0% +felt often bring a kind of smoothness or + + + align:start position:0% +felt often bring a kind of smoothness or +a fluidity to their performance that is + + align:start position:0% +a fluidity to their performance that is + + + align:start position:0% +a fluidity to their performance that is +inherently artificial so many neorealist + + align:start position:0% +inherently artificial so many neorealist + + + align:start position:0% +inherently artificial so many neorealist +films have no or virtually no + + align:start position:0% +films have no or virtually no + + + align:start position:0% +films have no or virtually no +professional actors in them or sometimes + + align:start position:0% +professional actors in them or sometimes + + + align:start position:0% +professional actors in them or sometimes +only professional actors in the major + + align:start position:0% +only professional actors in the major + + + align:start position:0% +only professional actors in the major +roles in the film you're going to see + + align:start position:0% +roles in the film you're going to see + + + align:start position:0% +roles in the film you're going to see +tonight the star is a nonprofessional + + align:start position:0% +tonight the star is a nonprofessional + + + align:start position:0% +tonight the star is a nonprofessional +actor he actually ended up having a + + align:start position:0% +actor he actually ended up having a + + + align:start position:0% +actor he actually ended up having a +tragic life the film won the Academy + + align:start position:0% +tragic life the film won the Academy + + + align:start position:0% +tragic life the film won the Academy +Award is the best foreign film of the + + align:start position:0% +Award is the best foreign film of the + + + align:start position:0% +Award is the best foreign film of the +year in the America in 1948 uh and the + + align:start position:0% +year in the America in 1948 uh and the + + + align:start position:0% +year in the America in 1948 uh and the +man who played Richi was an inter became + + align:start position:0% +man who played Richi was an inter became + + + align:start position:0% +man who played Richi was an inter became +an international star but he he uh fell + + align:start position:0% +an international star but he he uh fell + + + align:start position:0% +an international star but he he uh fell +into hard times and and and and ended up + + align:start position:0% +into hard times and and and and ended up + + + align:start position:0% +into hard times and and and and ended up +not not really making making much uh + + align:start position:0% +not not really making making much uh + + + align:start position:0% +not not really making making much uh +money off his + + align:start position:0% +money off his + + + align:start position:0% +money off his +off from his from his very brief stardom + + align:start position:0% +off from his from his very brief stardom + + + align:start position:0% +off from his from his very brief stardom +and then and and and my understanding is + + align:start position:0% +and then and and and my understanding is + + + align:start position:0% +and then and and and my understanding is +that that he that he uh uh U never again + + align:start position:0% +that that he that he uh uh U never again + + + align:start position:0% +that that he that he uh uh U never again +made a film as remarkable as as The + + align:start position:0% +made a film as remarkable as as The + + + align:start position:0% +made a film as remarkable as as The +Bicycle Thief but one of the things that + + align:start position:0% +Bicycle Thief but one of the things that + + + align:start position:0% +Bicycle Thief but one of the things that +is absolutely astonishing about the + + align:start position:0% +is absolutely astonishing about the + + + align:start position:0% +is absolutely astonishing about the +performance is that this man is not an + + align:start position:0% +performance is that this man is not an + + + align:start position:0% +performance is that this man is not an +actor you would never guess it I mean + + align:start position:0% +actor you would never guess it I mean + + + align:start position:0% +actor you would never guess it I mean +it's an absolute well maybe you would + + align:start position:0% +it's an absolute well maybe you would + + + align:start position:0% +it's an absolute well maybe you would +but you would guess it only after having + + align:start position:0% +but you would guess it only after having + + + align:start position:0% +but you would guess it only after having +been told uh that because he he performs + + align:start position:0% +been told uh that because he he performs + + + align:start position:0% +been told uh that because he he performs +with such naturalness and such Grace uh + + align:start position:0% +with such naturalness and such Grace uh + + + align:start position:0% +with such naturalness and such Grace uh +so the use of nonprofessional actors is + + align:start position:0% +so the use of nonprofessional actors is + + + align:start position:0% +so the use of nonprofessional actors is +a is one of the key features of + + align:start position:0% +a is one of the key features of + + + align:start position:0% +a is one of the key features of +neorealism a second key feature is a + + align:start position:0% +neorealism a second key feature is a + + + align:start position:0% +neorealism a second key feature is a +rejection of Studio filming all + + align:start position:0% +rejection of Studio filming all + + + align:start position:0% +rejection of Studio filming all +neorealist films like almost all poetic + + align:start position:0% +neorealist films like almost all poetic + + + align:start position:0% +neorealist films like almost all poetic +realism films realist films were shot + + align:start position:0% +realism films realist films were shot + + + align:start position:0% +realism films realist films were shot +outdoors in natural light partly because + + align:start position:0% +outdoors in natural light partly because + + + align:start position:0% +outdoors in natural light partly because +they wanted natural light and partly + + align:start position:0% +they wanted natural light and partly + + + align:start position:0% +they wanted natural light and partly +because Studios lie about the texture of + + align:start position:0% +because Studios lie about the texture of + + + align:start position:0% +because Studios lie about the texture of +the world we want the texture of the + + align:start position:0% +the world we want the texture of the + + + align:start position:0% +the world we want the texture of the +world in our films the ne our films are + + align:start position:0% +world in our films the ne our films are + + + align:start position:0% +world in our films the ne our films are +really about reality so we can't shoot + + align:start position:0% +really about reality so we can't shoot + + + align:start position:0% +really about reality so we can't shoot +in we we we can't shoot indoors a third + + align:start position:0% +in we we we can't shoot indoors a third + + + align:start position:0% +in we we we can't shoot indoors a third +nonprofessional actors outdoor camera a + + align:start position:0% +nonprofessional actors outdoor camera a + + + align:start position:0% +nonprofessional actors outdoor camera a +third feature would be what we might + + align:start position:0% +third feature would be what we might + + + align:start position:0% +third feature would be what we might +call a fundamental misen style taken + + align:start position:0% +call a fundamental misen style taken + + + align:start position:0% +call a fundamental misen style taken +directly from the the uh stylistic + + align:start position:0% +directly from the the uh stylistic + + + align:start position:0% +directly from the the uh stylistic +habits established by Jean Renoir and + + align:start position:0% +habits established by Jean Renoir and + + + align:start position:0% +habits established by Jean Renoir and +other French directors who worked in the + + align:start position:0% +other French directors who worked in the + + + align:start position:0% +other French directors who worked in the +same style uh relatively modest forms of + + align:start position:0% +same style uh relatively modest forms of + + + align:start position:0% +same style uh relatively modest forms of +editing the forms of Montage that you + + align:start position:0% +editing the forms of Montage that you + + + align:start position:0% +editing the forms of Montage that you +see are are not disruptive you won't get + + align:start position:0% +see are are not disruptive you won't get + + + align:start position:0% +see are are not disruptive you won't get +jump Cuts or or or disorienting moments + + align:start position:0% +jump Cuts or or or disorienting moments + + + align:start position:0% +jump Cuts or or or disorienting moments +the camera the camera is as with Renoir + + align:start position:0% +the camera the camera is as with Renoir + + + align:start position:0% +the camera the camera is as with Renoir +constantly restless and in but often in + + align:start position:0% +constantly restless and in but often in + + + align:start position:0% +constantly restless and in but often in +very gentle ways there's a wonderful Mo + + align:start position:0% +very gentle ways there's a wonderful Mo + + + align:start position:0% +very gentle ways there's a wonderful Mo +moment in the scene I mentioned a moment + + align:start position:0% +moment in the scene I mentioned a moment + + + align:start position:0% +moment in the scene I mentioned a moment +ago where we see Richi putting up his + + align:start position:0% +ago where we see Richi putting up his + + + align:start position:0% +ago where we see Richi putting up his +first poster when the camera is watching + + align:start position:0% +first poster when the camera is watching + + + align:start position:0% +first poster when the camera is watching +them and and and he's getting these + + align:start position:0% +them and and and he's getting these + + + align:start position:0% +them and and and he's getting these +instructions from his comrade about how + + align:start position:0% +instructions from his comrade about how + + + align:start position:0% +instructions from his comrade about how +to put the thing up and it's really + + align:start position:0% +to put the thing up and it's really + + + align:start position:0% +to put the thing up and it's really +boring well the we one reason that you + + align:start position:0% +boring well the we one reason that you + + + align:start position:0% +boring well the we one reason that you +know it's boring obviously you as a + + align:start position:0% +know it's boring obviously you as a + + + align:start position:0% +know it's boring obviously you as a +viewer you begin to probably feel it + + align:start position:0% +viewer you begin to probably feel it + + + align:start position:0% +viewer you begin to probably feel it +without registering that it's boring but + + align:start position:0% +without registering that it's boring but + + + align:start position:0% +without registering that it's boring but +the way reason that you know it is is + + align:start position:0% +the way reason that you know it is is + + + align:start position:0% +the way reason that you know it is is +that the camera suddenly looks away what + + align:start position:0% +that the camera suddenly looks away what + + + align:start position:0% +that the camera suddenly looks away what +happens is the camera discovers + + align:start position:0% +happens is the camera discovers + + + align:start position:0% +happens is the camera discovers +something something interesting + + align:start position:0% +something something interesting + + + align:start position:0% +something something interesting +happening on the street and while the + + align:start position:0% +happening on the street and while the + + + align:start position:0% +happening on the street and while the +conversation continues on the soundtrack + + align:start position:0% +conversation continues on the soundtrack + + + align:start position:0% +conversation continues on the soundtrack +the camera shifts away from Richi and + + align:start position:0% +the camera shifts away from Richi and + + + align:start position:0% +the camera shifts away from Richi and +his instructor and follows uh a wealthy + + align:start position:0% +his instructor and follows uh a wealthy + + + align:start position:0% +his instructor and follows uh a wealthy +man and two children who are walking + + align:start position:0% +man and two children who are walking + + + align:start position:0% +man and two children who are walking +behind him and they're really Beggars + + align:start position:0% +behind him and they're really Beggars + + + align:start position:0% +behind him and they're really Beggars +trying to get money from him and the + + align:start position:0% +trying to get money from him and the + + + align:start position:0% +trying to get money from him and the +camera just just it found it interesting + + align:start position:0% +camera just just it found it interesting + + + align:start position:0% +camera just just it found it interesting +so it looked at it a very Jean Ren + + align:start position:0% +so it looked at it a very Jean Ren + + + align:start position:0% +so it looked at it a very Jean Ren +noirish move there are other moves like + + align:start position:0% +noirish move there are other moves like + + + align:start position:0% +noirish move there are other moves like +this so uh in the in the film as if the + + align:start position:0% +this so uh in the in the film as if the + + + align:start position:0% +this so uh in the in the film as if the +camera like je renoir's camera is uh so + + align:start position:0% +camera like je renoir's camera is uh so + + + align:start position:0% +camera like je renoir's camera is uh so +interested in the world that it's + + align:start position:0% +interested in the world that it's + + + align:start position:0% +interested in the world that it's +capable of being distracted there's a + + align:start position:0% +capable of being distracted there's a + + + align:start position:0% +capable of being distracted there's a +that the world's complexity is always + + align:start position:0% +that the world's complexity is always + + + align:start position:0% +that the world's complexity is always +threatening uh the the coherences and + + align:start position:0% +threatening uh the the coherences and + + + align:start position:0% +threatening uh the the coherences and +meanings that the film is releasing for + + align:start position:0% +meanings that the film is releasing for + + + align:start position:0% +meanings that the film is releasing for +us so nonprofessional actors outdoor + + align:start position:0% +us so nonprofessional actors outdoor + + + align:start position:0% +us so nonprofessional actors outdoor +filming a Misan a a profound serious + + align:start position:0% +filming a Misan a a profound serious + + + align:start position:0% +filming a Misan a a profound serious +Misan style influenced by deeply by Jean + + align:start position:0% +Misan style influenced by deeply by Jean + + + align:start position:0% +Misan style influenced by deeply by Jean +Renoir and finally we might maybe + + align:start position:0% +Renoir and finally we might maybe + + + align:start position:0% +Renoir and finally we might maybe +another not finally one more a fourth + + align:start position:0% +another not finally one more a fourth + + + align:start position:0% +another not finally one more a fourth +feature we might say is what what I what + + align:start position:0% +feature we might say is what what I what + + + align:start position:0% +feature we might say is what what I what +I was trying to indicate when I talked + + align:start position:0% +I was trying to indicate when I talked + + + align:start position:0% +I was trying to indicate when I talked +about the social or political bias of + + align:start position:0% +about the social or political bias of + + + align:start position:0% +about the social or political bias of +these films one might say that these + + align:start position:0% +these films one might say that these + + + align:start position:0% +these films one might say that these +films have a more profoundly documentary + + align:start position:0% +films have a more profoundly documentary + + + align:start position:0% +films have a more profoundly documentary +flavor I don't mean that we feel we're + + align:start position:0% +flavor I don't mean that we feel we're + + + align:start position:0% +flavor I don't mean that we feel we're +watching documentaries but we watch we + + align:start position:0% +watching documentaries but we watch we + + + align:start position:0% +watching documentaries but we watch we +do feel we're watching a slice of life + + align:start position:0% +do feel we're watching a slice of life + + + align:start position:0% +do feel we're watching a slice of life +that the uh economic and moral and + + align:start position:0% +that the uh economic and moral and + + + align:start position:0% +that the uh economic and moral and +social and personal circumstances of the + + align:start position:0% +social and personal circumstances of the + + + align:start position:0% +social and personal circumstances of the +characters we see in neorealist films + + align:start position:0% +characters we see in neorealist films + + + align:start position:0% +characters we see in neorealist films +are a version of what we would find if + + align:start position:0% +are a version of what we would find if + + + align:start position:0% +are a version of what we would find if +we walked into Rome not in a movie and + + align:start position:0% +we walked into Rome not in a movie and + + + align:start position:0% +we walked into Rome not in a movie and +just look for people of this class right + + align:start position:0% +just look for people of this class right + + + align:start position:0% +just look for people of this class right +a documentary flavor so that's four + + align:start position:0% +a documentary flavor so that's four + + + align:start position:0% +a documentary flavor so that's four +features and a final feature that I + + align:start position:0% +features and a final feature that I + + + align:start position:0% +features and a final feature that I +suppose I would want to add has to do do + + align:start position:0% +suppose I would want to add has to do do + + + align:start position:0% +suppose I would want to add has to do do +with the relation between plot and + + align:start position:0% +with the relation between plot and + + + align:start position:0% +with the relation between plot and +character it's not quite true to say + + align:start position:0% +character it's not quite true to say + + + align:start position:0% +character it's not quite true to say +that these films are plotless they're + + align:start position:0% +that these films are plotless they're + + + align:start position:0% +that these films are plotless they're +not and one of the most magnificent + + align:start position:0% +not and one of the most magnificent + + + align:start position:0% +not and one of the most magnificent +things about The Bicycle Thief is the + + align:start position:0% +things about The Bicycle Thief is the + + + align:start position:0% +things about The Bicycle Thief is the +economy of its plot and I'll talk a bit + + align:start position:0% +economy of its plot and I'll talk a bit + + + align:start position:0% +economy of its plot and I'll talk a bit +about that tonight but it's nonetheless + + align:start position:0% +about that tonight but it's nonetheless + + + align:start position:0% +about that tonight but it's nonetheless +true that in neorealist films you do not + + align:start position:0% +true that in neorealist films you do not + + + align:start position:0% +true that in neorealist films you do not +feel that action drives events what you + + align:start position:0% +feel that action drives events what you + + + align:start position:0% +feel that action drives events what you +feel is that character drives events in + + align:start position:0% +feel is that character drives events in + + + align:start position:0% +feel is that character drives events in +some sense that the that the plot is a + + align:start position:0% +some sense that the that the plot is a + + + align:start position:0% +some sense that the that the plot is a +what the plot aims for is a natural + + align:start position:0% +what the plot aims for is a natural + + + align:start position:0% +what the plot aims for is a natural +unfolding you're never supposed to feel + + align:start position:0% +unfolding you're never supposed to feel + + + align:start position:0% +unfolding you're never supposed to feel +in a neorealist film uh that that up + + align:start position:0% +in a neorealist film uh that that up + + + align:start position:0% +in a neorealist film uh that that up +some event in the plot has been + + align:start position:0% +some event in the plot has been + + + align:start position:0% +some event in the plot has been +introduced arbitrarily you're never + + align:start position:0% +introduced arbitrarily you're never + + + align:start position:0% +introduced arbitrarily you're never +supposed to step back and say oh that + + align:start position:0% +supposed to step back and say oh that + + + align:start position:0% +supposed to step back and say oh that +could never happen that how implausible + + align:start position:0% +could never happen that how implausible + + + align:start position:0% +could never happen that how implausible +is that or I guess they did that because + + align:start position:0% +is that or I guess they did that because + + + align:start position:0% +is that or I guess they did that because +they wanted to show X right the kind of + + align:start position:0% +they wanted to show X right the kind of + + + align:start position:0% +they wanted to show X right the kind of +response you often have watching certain + + align:start position:0% +response you often have watching certain + + + align:start position:0% +response you often have watching certain +forms + + align:start position:0% +forms + + + align:start position:0% +forms +of Hollywood entertainment and and other + + align:start position:0% +of Hollywood entertainment and and other + + + align:start position:0% +of Hollywood entertainment and and other +other forms of merely Escapist uh uh + + align:start position:0% +other forms of merely Escapist uh uh + + + align:start position:0% +other forms of merely Escapist uh uh +entertainment fair but you don't ever + + align:start position:0% +entertainment fair but you don't ever + + + align:start position:0% +entertainment fair but you don't ever +have that feeling in a in a good real + + align:start position:0% +have that feeling in a in a good real + + + align:start position:0% +have that feeling in a in a good real +neorealist film what you feel is that + + align:start position:0% +neorealist film what you feel is that + + + align:start position:0% +neorealist film what you feel is that +the events of the plot unfold naturally + + align:start position:0% +the events of the plot unfold naturally + + + align:start position:0% +the events of the plot unfold naturally +out of the economic and social realities + + align:start position:0% +out of the economic and social realities + + + align:start position:0% +out of the economic and social realities +the characters live in and out of their + + align:start position:0% +the characters live in and out of their + + + align:start position:0% +the characters live in and out of their +characters you can test this + + align:start position:0% +characters you can test this + + + align:start position:0% +characters you can test this +generalization against tonight's film + + align:start position:0% +generalization against tonight's film + + + align:start position:0% +generalization against tonight's film +and I'm sure that you'll find that it's + + align:start position:0% +and I'm sure that you'll find that it's + + + align:start position:0% +and I'm sure that you'll find that it's +a compelling one that it really + + align:start position:0% +a compelling one that it really + + + align:start position:0% +a compelling one that it really +describes this + + align:start position:0% +describes this + + + align:start position:0% +describes this +movement's respect for the complexity of + + align:start position:0% +movement's respect for the complexity of + + + align:start position:0% +movement's respect for the complexity of +character over plot for for the + + align:start position:0% +character over plot for for the + + + align:start position:0% +character over plot for for the +complexity of character and therefore + + align:start position:0% +complexity of character and therefore + + + align:start position:0% +complexity of character and therefore +for its commitment to a kind of movie + + align:start position:0% +for its commitment to a kind of movie + + + align:start position:0% +for its commitment to a kind of movie +that is more interested in character + + align:start position:0% +that is more interested in character + + + align:start position:0% +that is more interested in character +than it is in in in story or event in a + + align:start position:0% +than it is in in in story or event in a + + + align:start position:0% +than it is in in in story or event in a +narrow + + align:start position:0% + + + + align:start position:0% + +sense the central figures of neorealism + + align:start position:0% +sense the central figures of neorealism + + + align:start position:0% +sense the central figures of neorealism +are important to mention and maybe + + align:start position:0% +are important to mention and maybe + + + align:start position:0% +are important to mention and maybe +especially the fellow that I have first + + align:start position:0% +especially the fellow that I have first + + + align:start position:0% +especially the fellow that I have first +on my list here um chz zaatini uh + + align:start position:0% +on my list here um chz zaatini uh + + + align:start position:0% +on my list here um chz zaatini uh +because he's the least well-known of the + + align:start position:0% +because he's the least well-known of the + + + align:start position:0% +because he's the least well-known of the +names I've listed there the other three + + align:start position:0% +names I've listed there the other three + + + align:start position:0% +names I've listed there the other three +names are all famous directors and of + + align:start position:0% +names are all famous directors and of + + + align:start position:0% +names are all famous directors and of +course Desa is the director of bicycle + + align:start position:0% +course Desa is the director of bicycle + + + align:start position:0% +course Desa is the director of bicycle +thieves and I'll talk about his career + + align:start position:0% +thieves and I'll talk about his career + + + align:start position:0% +thieves and I'll talk about his career +this evening but zaatini was the + + align:start position:0% +this evening but zaatini was the + + + align:start position:0% +this evening but zaatini was the +theoretical gen genus behind neorealism + + align:start position:0% +theoretical gen genus behind neorealism + + + align:start position:0% +theoretical gen genus behind neorealism +and a figure for whom I still retain a + + align:start position:0% +and a figure for whom I still retain a + + + align:start position:0% +and a figure for whom I still retain a +tremendous uh sympathy and affection uh + + align:start position:0% +tremendous uh sympathy and affection uh + + + align:start position:0% +tremendous uh sympathy and affection uh +he he was a novelist and a an essay + + align:start position:0% +he he was a novelist and a an essay + + + align:start position:0% +he he was a novelist and a an essay +writer uh uh as well as a uh screen + + align:start position:0% +writer uh uh as well as a uh screen + + + align:start position:0% +writer uh uh as well as a uh screen +screenwriter uh he collaborated + + align:start position:0% +screenwriter uh he collaborated + + + align:start position:0% +screenwriter uh he collaborated +with with um Victorio Desa on almost + + align:start position:0% +with with um Victorio Desa on almost + + + align:start position:0% +with with um Victorio Desa on almost +every one of desa's significant films + + align:start position:0% +every one of desa's significant films + + + align:start position:0% +every one of desa's significant films +not on everyone but on virtually + + align:start position:0% +not on everyone but on virtually + + + align:start position:0% +not on everyone but on virtually +everyone that is truly outstanding and + + align:start position:0% +everyone that is truly outstanding and + + + align:start position:0% +everyone that is truly outstanding and +there are a number of them he's a he's + + align:start position:0% +there are a number of them he's a he's + + + align:start position:0% +there are a number of them he's a he's +the the script writer on and he he had a + + align:start position:0% +the the script writer on and he he had a + + + align:start position:0% +the the script writer on and he he had a +particularly symbiotic relation to Desa + + align:start position:0% +particularly symbiotic relation to Desa + + + align:start position:0% +particularly symbiotic relation to Desa +zaatini also articulated what came to be + + align:start position:0% +zaatini also articulated what came to be + + + align:start position:0% +zaatini also articulated what came to be +understood as the manifesto of + + align:start position:0% +understood as the manifesto of + + + align:start position:0% +understood as the manifesto of +neorealism and in one such essay I don't + + align:start position:0% +neorealism and in one such essay I don't + + + align:start position:0% +neorealism and in one such essay I don't +know it was titled Manifesto of + + align:start position:0% +know it was titled Manifesto of + + + align:start position:0% +know it was titled Manifesto of +neorealism but that was its effect he + + align:start position:0% +neorealism but that was its effect he + + + align:start position:0% +neorealism but that was its effect he +said this to try to summarize what he + + align:start position:0% +said this to try to summarize what he + + + align:start position:0% +said this to try to summarize what he +thought the Ambitions of neorealism were + + align:start position:0% +thought the Ambitions of neorealism were + + + align:start position:0% +thought the Ambitions of neorealism were +he said a good film ought to be focused + + align:start position:0% +he said a good film ought to be focused + + + align:start position:0% +he said a good film ought to be focused +on if on the life of an ordinary man to + + align:start position:0% +on if on the life of an ordinary man to + + + align:start position:0% +on if on the life of an ordinary man to +whom nothing + + align:start position:0% +whom nothing + + + align:start position:0% +whom nothing +happens now he didn't really mean that + + align:start position:0% +happens now he didn't really mean that + + + align:start position:0% +happens now he didn't really mean that +nothing would happen right um it's not + + align:start position:0% +nothing would happen right um it's not + + + align:start position:0% +nothing would happen right um it's not +it's not an early version of the + + align:start position:0% +it's not an early version of the + + + align:start position:0% +it's not an early version of the +Seinfeld program uh what what what what + + align:start position:0% +Seinfeld program uh what what what what + + + align:start position:0% +Seinfeld program uh what what what what +what what he's trying to get at is this + + align:start position:0% +what what he's trying to get at is this + + + align:start position:0% +what what he's trying to get at is this +idea that plot does not dominate that + + align:start position:0% +idea that plot does not dominate that + + + align:start position:0% +idea that plot does not dominate that +character dominates that the events of + + align:start position:0% +character dominates that the events of + + + align:start position:0% +character dominates that the events of +the story grow organically out of the + + align:start position:0% +the story grow organically out of the + + + align:start position:0% +the story grow organically out of the +materials of the of the text both out of + + align:start position:0% +materials of the of the text both out of + + + align:start position:0% +materials of the of the text both out of +character and out of out of out out of + + align:start position:0% +character and out of out of out out of + + + align:start position:0% +character and out of out of out out of +social out of social + + align:start position:0% +social out of social + + + align:start position:0% +social out of social +realities um so + + align:start position:0% +realities um so + + + align:start position:0% +realities um so +uh zavi was in many ways a a Visionary + + align:start position:0% +uh zavi was in many ways a a Visionary + + + align:start position:0% +uh zavi was in many ways a a Visionary +figure + + align:start position:0% +figure + + + align:start position:0% +figure +um an overt Marxist for a good part for + + align:start position:0% +um an overt Marxist for a good part for + + + align:start position:0% +um an overt Marxist for a good part for +a good part of his life and probably the + + align:start position:0% +a good part of his life and probably the + + + align:start position:0% +a good part of his life and probably the +central + + align:start position:0% +central + + + align:start position:0% +central +intellectual influence on the neorealist + + align:start position:0% +intellectual influence on the neorealist + + + align:start position:0% +intellectual influence on the neorealist +movement Visconti the uh the director + + align:start position:0% +movement Visconti the uh the director + + + align:start position:0% +movement Visconti the uh the director +whose dates I've put there uh is + + align:start position:0% +whose dates I've put there uh is + + + align:start position:0% +whose dates I've put there uh is +sometimes + + align:start position:0% +sometimes + + + align:start position:0% +sometimes +suggested it is often said that not all + + align:start position:0% +suggested it is often said that not all + + + align:start position:0% +suggested it is often said that not all +of this con's work fits neatly maybe + + align:start position:0% +of this con's work fits neatly maybe + + + align:start position:0% +of this con's work fits neatly maybe +none of it fits neatly into the category + + align:start position:0% +none of it fits neatly into the category + + + align:start position:0% +none of it fits neatly into the category +of neorealism uh this partly has to do + + align:start position:0% +of neorealism uh this partly has to do + + + align:start position:0% +of neorealism uh this partly has to do +with a with a a kind of flamboyance in + + align:start position:0% +with a with a a kind of flamboyance in + + + align:start position:0% +with a with a a kind of flamboyance in +in in in Vis country's visual style and + + align:start position:0% +in in in Vis country's visual style and + + + align:start position:0% +in in in Vis country's visual style and +maybe also a fness for decadence and for + + align:start position:0% +maybe also a fness for decadence and for + + + align:start position:0% +maybe also a fness for decadence and for +and for um elaboration that does + + align:start position:0% +and for um elaboration that does + + + align:start position:0% +and for um elaboration that does +not comport with the social meanings + + align:start position:0% +not comport with the social meanings + + + align:start position:0% +not comport with the social meanings +that are implicit in neorealism so he's + + align:start position:0% +that are implicit in neorealism so he's + + + align:start position:0% +that are implicit in neorealism so he's +the uh of the main neorealists he's the + + align:start position:0% +the uh of the main neorealists he's the + + + align:start position:0% +the uh of the main neorealists he's the +he's the one who fits least as well but + + align:start position:0% +he's the one who fits least as well but + + + align:start position:0% +he's the one who fits least as well but +he's often said to be the best of them + + align:start position:0% +he's often said to be the best of them + + + align:start position:0% +he's often said to be the best of them +and there are many uh uh historians of + + align:start position:0% +and there are many uh uh historians of + + + align:start position:0% +and there are many uh uh historians of +film and Scholars of film including + + align:start position:0% +film and Scholars of film including + + + align:start position:0% +film and Scholars of film including +David Cook who believed that the Earth + + align:start position:0% +David Cook who believed that the Earth + + + align:start position:0% +David Cook who believed that the Earth +trembles the film that he made in uh in + + align:start position:0% +trembles the film that he made in uh in + + + align:start position:0% +trembles the film that he made in uh in +1948 laa Tria the Earth trembles is the + + align:start position:0% +1948 laa Tria the Earth trembles is the + + + align:start position:0% +1948 laa Tria the Earth trembles is the +greatest of all neorealist movies I have + + align:start position:0% +greatest of all neorealist movies I have + + + align:start position:0% +greatest of all neorealist movies I have +sometimes been tempted to show it but + + align:start position:0% +sometimes been tempted to show it but + + + align:start position:0% +sometimes been tempted to show it but +it's less characteristic of neorealism + + align:start position:0% +it's less characteristic of neorealism + + + align:start position:0% +it's less characteristic of neorealism +so I don't show it but it is a very + + align:start position:0% +so I don't show it but it is a very + + + align:start position:0% +so I don't show it but it is a very +remarkable film and and uh Visconti is a + + align:start position:0% +remarkable film and and uh Visconti is a + + + align:start position:0% +remarkable film and and uh Visconti is a +very important figure in this in this + + align:start position:0% +very important figure in this in this + + + align:start position:0% +very important figure in this in this +movement even though he probably can be + + align:start position:0% +movement even though he probably can be + + + align:start position:0% +movement even though he probably can be +said in his later films to to move + + align:start position:0% +said in his later films to to move + + + align:start position:0% +said in his later films to to move +Beyond neorealist concerns Roberto + + align:start position:0% +Beyond neorealist concerns Roberto + + + align:start position:0% +Beyond neorealist concerns Roberto +rosolini who also had a very rich long + + align:start position:0% +rosolini who also had a very rich long + + + align:start position:0% +rosolini who also had a very rich long +career as a filmmaker and I've only + + align:start position:0% +career as a filmmaker and I've only + + + align:start position:0% +career as a filmmaker and I've only +listed his uh uh one film there because + + align:start position:0% +listed his uh uh one film there because + + + align:start position:0% +listed his uh uh one film there because +I want to show you a clip from it uh + + align:start position:0% +I want to show you a clip from it uh + + + align:start position:0% +I want to show you a clip from it uh +part of a Trilogy of films he made at + + align:start position:0% +part of a Trilogy of films he made at + + + align:start position:0% +part of a Trilogy of films he made at +the very end of the war called uh it was + + align:start position:0% +the very end of the war called uh it was + + + align:start position:0% +the very end of the war called uh it was +called his Roman Trilogy or his Rome + + align:start position:0% +called his Roman Trilogy or his Rome + + + align:start position:0% +called his Roman Trilogy or his Rome +Trilogy and the first one was or his + + align:start position:0% +Trilogy and the first one was or his + + + align:start position:0% +Trilogy and the first one was or his +World War II trilogy olog uh the first + + align:start position:0% +World War II trilogy olog uh the first + + + align:start position:0% +World War II trilogy olog uh the first +one was called Rome Open City and then + + align:start position:0% +one was called Rome Open City and then + + + align:start position:0% +one was called Rome Open City and then +there were two other uh the third one + + align:start position:0% +there were two other uh the third one + + + align:start position:0% +there were two other uh the third one +was called Germany year zero and they + + align:start position:0% +was called Germany year zero and they + + + align:start position:0% +was called Germany year zero and they +they all had sort of uh uh political and + + align:start position:0% +they all had sort of uh uh political and + + + align:start position:0% +they all had sort of uh uh political and +social Ambitions they wanted to + + align:start position:0% +social Ambitions they wanted to + + + align:start position:0% +social Ambitions they wanted to +dramatize the post-war conditions and + + align:start position:0% +dramatize the post-war conditions and + + + align:start position:0% +dramatize the post-war conditions and +show the devastation that followed uh + + align:start position:0% +show the devastation that followed uh + + + align:start position:0% +show the devastation that followed uh +the the aftermath that that was the + + align:start position:0% +the the aftermath that that was the + + + align:start position:0% +the the aftermath that that was the +aftermath of the second World War uh + + align:start position:0% +aftermath of the second World War uh + + + align:start position:0% +aftermath of the second World War uh +open + + align:start position:0% +open + + + align:start position:0% +open +city um had a tremendous impact when it + + align:start position:0% +city um had a tremendous impact when it + + + align:start position:0% +city um had a tremendous impact when it +was first uh uh released especially in + + align:start position:0% +was first uh uh released especially in + + + align:start position:0% +was first uh uh released especially in +Italy because it told an anti-fascist + + align:start position:0% +Italy because it told an anti-fascist + + + align:start position:0% +Italy because it told an anti-fascist +story uh it's a somewhat melodramatic + + align:start position:0% +story uh it's a somewhat melodramatic + + + align:start position:0% +story uh it's a somewhat melodramatic +film that that ends in a very uh in a + + align:start position:0% +film that that ends in a very uh in a + + + align:start position:0% +film that that ends in a very uh in a +very melodramatic uh death in a very + + align:start position:0% +very melodramatic uh death in a very + + + align:start position:0% +very melodramatic uh death in a very +melodramatic murder U or an accidental + + align:start position:0% +melodramatic murder U or an accidental + + + align:start position:0% +melodramatic murder U or an accidental +murder um uh and and and and partly for + + align:start position:0% +murder um uh and and and and partly for + + + align:start position:0% +murder um uh and and and and partly for +that reason it's it's a a less it's a + + align:start position:0% +that reason it's it's a a less it's a + + + align:start position:0% +that reason it's it's a a less it's a +less powerful and less compelling uh + + align:start position:0% +less powerful and less compelling uh + + + align:start position:0% +less powerful and less compelling uh +film totally than something like bicycle + + align:start position:0% +film totally than something like bicycle + + + align:start position:0% +film totally than something like bicycle +thieves uh but it but but its importance + + align:start position:0% +thieves uh but it but but its importance + + + align:start position:0% +thieves uh but it but but its importance +is can't be overestimated + + align:start position:0% +is can't be overestimated + + + align:start position:0% +is can't be overestimated +it it established the basic principles + + align:start position:0% +it it established the basic principles + + + align:start position:0% +it it established the basic principles +that I've been talking about it was + + align:start position:0% +that I've been talking about it was + + + align:start position:0% +that I've been talking about it was +actually begun before the war was over + + align:start position:0% +actually begun before the war was over + + + align:start position:0% +actually begun before the war was over +when it was illegal to when when the + + align:start position:0% +when it was illegal to when when the + + + align:start position:0% +when it was illegal to when when the +when the German authorities were fascist + + align:start position:0% +when the German authorities were fascist + + + align:start position:0% +when the German authorities were fascist +authorities were still controlling uh + + align:start position:0% +authorities were still controlling uh + + + align:start position:0% +authorities were still controlling uh +Rome and Italian society and you weren't + + align:start position:0% +Rome and Italian society and you weren't + + + align:start position:0% +Rome and Italian society and you weren't +supposed you couldn't film without a + + align:start position:0% +supposed you couldn't film without a + + + align:start position:0% +supposed you couldn't film without a +license and some of the early scenes + + align:start position:0% +license and some of the early scenes + + + align:start position:0% +license and some of the early scenes +from Rome Open City were actually shot + + align:start position:0% +from Rome Open City were actually shot + + + align:start position:0% +from Rome Open City were actually shot +illicitly on very bad film stock uh from + + align:start position:0% +illicitly on very bad film stock uh from + + + align:start position:0% +illicitly on very bad film stock uh from +behind doorways and around corners so + + align:start position:0% +behind doorways and around corners so + + + align:start position:0% +behind doorways and around corners so +the people uh the people behind the + + align:start position:0% +the people uh the people behind the + + + align:start position:0% +the people uh the people behind the +camera wouldn't be caught by the + + align:start position:0% +camera wouldn't be caught by the + + + align:start position:0% +camera wouldn't be caught by the +authorities and then the film was + + align:start position:0% +authorities and then the film was + + + align:start position:0% +authorities and then the film was +completed after peace came and after + + align:start position:0% +completed after peace came and after + + + align:start position:0% +completed after peace came and after +after the after the uh uh defeat of the + + align:start position:0% +after the after the uh uh defeat of the + + + align:start position:0% +after the after the uh uh defeat of the +axis forces um I'm going to show you a + + align:start position:0% +axis forces um I'm going to show you a + + + align:start position:0% +axis forces um I'm going to show you a +clip from that sequence from that film + + align:start position:0% +clip from that sequence from that film + + + align:start position:0% +clip from that sequence from that film +from the very beginning of that film to + + align:start position:0% +from the very beginning of that film to + + + align:start position:0% +from the very beginning of that film to +give you a feel for what that film was + + align:start position:0% +give you a feel for what that film was + + + align:start position:0% +give you a feel for what that film was +like as well and I think that that clip + + align:start position:0% +like as well and I think that that clip + + + align:start position:0% +like as well and I think that that clip +will also show you why the film was so + + align:start position:0% +will also show you why the film was so + + + align:start position:0% +will also show you why the film was so +successful but I'll partly explain it + + align:start position:0% +successful but I'll partly explain it + + + align:start position:0% +successful but I'll partly explain it +now I think the Italians loved this + + align:start position:0% +now I think the Italians loved this + + + align:start position:0% +now I think the Italians loved this +movie because it told a useful myth it + + align:start position:0% +movie because it told a useful myth it + + + align:start position:0% +movie because it told a useful myth it +made it made it appear that very few + + align:start position:0% +made it made it appear that very few + + + align:start position:0% +made it made it appear that very few +Italians collaborated with the Nazis and + + align:start position:0% +Italians collaborated with the Nazis and + + + align:start position:0% +Italians collaborated with the Nazis and +that most Italians were really on the + + align:start position:0% +that most Italians were really on the + + + align:start position:0% +that most Italians were really on the +side of the sabur who were trying to + + align:start position:0% +side of the sabur who were trying to + + + align:start position:0% +side of the sabur who were trying to +blow up fascist Waterworks and F this is + + align:start position:0% +blow up fascist Waterworks and F this is + + + align:start position:0% +blow up fascist Waterworks and F this is +probably not entirely historically + + align:start position:0% +probably not entirely historically + + + align:start position:0% +probably not entirely historically +accurate since melini was during much of + + align:start position:0% +accurate since melini was during much of + + + align:start position:0% +accurate since melini was during much of +his career a very popular figure in + + align:start position:0% +his career a very popular figure in + + + align:start position:0% +his career a very popular figure in +Italy but you can certainly understand + + align:start position:0% +Italy but you can certainly understand + + + align:start position:0% +Italy but you can certainly understand +why it would have uh U hit a sympathetic + + align:start position:0% +why it would have uh U hit a sympathetic + + + align:start position:0% +why it would have uh U hit a sympathetic +cord among Italians many of whom I'm + + align:start position:0% +cord among Italians many of whom I'm + + + align:start position:0% +cord among Italians many of whom I'm +sure felt terrible ambivalence and shame + + align:start position:0% +sure felt terrible ambivalence and shame + + + align:start position:0% +sure felt terrible ambivalence and shame +over the over the events of the of the + + align:start position:0% +over the over the events of the of the + + + align:start position:0% +over the over the events of the of the +second world war the Italians were + + align:start position:0% +second world war the Italians were + + + align:start position:0% +second world war the Italians were +always much more reluctant anti-semites + + align:start position:0% +always much more reluctant anti-semites + + + align:start position:0% +always much more reluctant anti-semites +than the Hitler fascists were and the + + align:start position:0% +than the Hitler fascists were and the + + + align:start position:0% +than the Hitler fascists were and the +story of Italian anti anti-Semitism is + + align:start position:0% +story of Italian anti anti-Semitism is + + + align:start position:0% +story of Italian anti anti-Semitism is +much more complicated than the story of + + align:start position:0% +much more complicated than the story of + + + align:start position:0% +much more complicated than the story of +of of German + + align:start position:0% +of of German + + + align:start position:0% +of of German +anti-Semitism uh in this in this period + + align:start position:0% +anti-Semitism uh in this in this period + + + align:start position:0% +anti-Semitism uh in this in this period +especially so I so I think that one + + align:start position:0% +especially so I so I think that one + + + align:start position:0% +especially so I so I think that one +reason for the success of the film had + + align:start position:0% +reason for the success of the film had + + + align:start position:0% +reason for the success of the film had +to do with the way it told a kind of + + align:start position:0% +to do with the way it told a kind of + + + align:start position:0% +to do with the way it told a kind of +anti-fascist fable that worked + + align:start position:0% +anti-fascist fable that worked + + + align:start position:0% +anti-fascist fable that worked +particularly well for this post-war + + align:start position:0% +particularly well for this post-war + + + align:start position:0% +particularly well for this post-war +society that wanted to put fascism + + align:start position:0% +society that wanted to put fascism + + + align:start position:0% +society that wanted to put fascism +behind it that wanted to repudiate that + + align:start position:0% +behind it that wanted to repudiate that + + + align:start position:0% +behind it that wanted to repudiate that +past that felt there were certainly + + align:start position:0% +past that felt there were certainly + + + align:start position:0% +past that felt there were certainly +segments of the population that had + + align:start position:0% +segments of the population that had + + + align:start position:0% +segments of the population that had +never gone along with that past anyway + + align:start position:0% +never gone along with that past anyway + + + align:start position:0% +never gone along with that past anyway +so the film sort of mobilized uh a feel + + align:start position:0% +so the film sort of mobilized uh a feel + + + align:start position:0% +so the film sort of mobilized uh a feel +a new kind of feeling of Italian + + align:start position:0% +a new kind of feeling of Italian + + + align:start position:0% +a new kind of feeling of Italian +patriotism and maybe even some in in + + align:start position:0% +patriotism and maybe even some in in + + + align:start position:0% +patriotism and maybe even some in in +some sense uh uh a kind of despite the + + align:start position:0% +some sense uh uh a kind of despite the + + + align:start position:0% +some sense uh uh a kind of despite the +catastrophe in which it ends a kind of + + align:start position:0% +catastrophe in which it ends a kind of + + + align:start position:0% +catastrophe in which it ends a kind of +hope for the future because the film + + align:start position:0% +hope for the future because the film + + + align:start position:0% +hope for the future because the film +takes place entirely within the period + + align:start position:0% +takes place entirely within the period + + + align:start position:0% +takes place entirely within the period +when the when when the fascists were + + align:start position:0% +when the when when the fascists were + + + align:start position:0% +when the when when the fascists were +still in control of of Italy and the + + align:start position:0% +still in control of of Italy and the + + + align:start position:0% +still in control of of Italy and the +catastrophe that occurs at the end is a + + align:start position:0% +catastrophe that occurs at the end is a + + + align:start position:0% +catastrophe that occurs at the end is a +is a is an is an act of fascist uh + + align:start position:0% +is a is an is an act of fascist uh + + + align:start position:0% +is a is an is an act of fascist uh +murder and + + align:start position:0% +murder and + + + align:start position:0% +murder and +assassin and indifference to humanity uh + + align:start position:0% +assassin and indifference to humanity uh + + + align:start position:0% +assassin and indifference to humanity uh +the so so so um uh Ros rosalini went on + + align:start position:0% +the so so so um uh Ros rosalini went on + + + align:start position:0% +the so so so um uh Ros rosalini went on +to make many many films and I I feel a + + align:start position:0% +to make many many films and I I feel a + + + align:start position:0% +to make many many films and I I feel a +little guilty only mentioning this one + + align:start position:0% +little guilty only mentioning this one + + + align:start position:0% +little guilty only mentioning this one +uh not totally characteristic film of + + align:start position:0% +uh not totally characteristic film of + + + align:start position:0% +uh not totally characteristic film of +his but it's important in the history of + + align:start position:0% +his but it's important in the history of + + + align:start position:0% +his but it's important in the history of +neorealism rosalini is a director I much + + align:start position:0% +neorealism rosalini is a director I much + + + align:start position:0% +neorealism rosalini is a director I much +admire partly because he moved away from + + align:start position:0% +admire partly because he moved away from + + + align:start position:0% +admire partly because he moved away from +fiction and at the end of his career he + + align:start position:0% +fiction and at the end of his career he + + + align:start position:0% +fiction and at the end of his career he +was he was making what he thought of as + + align:start position:0% +was he was making what he thought of as + + + align:start position:0% +was he was making what he thought of as +educational or instructional + + align:start position:0% +educational or instructional + + + align:start position:0% +educational or instructional +films but but but with the dazzling + + align:start position:0% +films but but but with the dazzling + + + align:start position:0% +films but but but with the dazzling +technique of a great fiction filmmaker + + align:start position:0% +technique of a great fiction filmmaker + + + align:start position:0% +technique of a great fiction filmmaker +so he's a very interesting figure to to + + align:start position:0% +so he's a very interesting figure to to + + + align:start position:0% +so he's a very interesting figure to to +study and to and I hope some of you will + + align:start position:0% +study and to and I hope some of you will + + + align:start position:0% +study and to and I hope some of you will +will look at more neorealist films and + + align:start position:0% +will look at more neorealist films and + + + align:start position:0% +will look at more neorealist films and +consider looking at + + align:start position:0% +consider looking at + + + align:start position:0% +consider looking at +rosolini Deek is the final figure uh + + align:start position:0% +rosolini Deek is the final figure uh + + + align:start position:0% +rosolini Deek is the final figure uh +that I want to mention as a as a + + align:start position:0% +that I want to mention as a as a + + + align:start position:0% +that I want to mention as a as a +fundamental uh uh energy in neorealism + + align:start position:0% +fundamental uh uh energy in neorealism + + + align:start position:0% +fundamental uh uh energy in neorealism +and I'll only say about him uh that he's + + align:start position:0% +and I'll only say about him uh that he's + + + align:start position:0% +and I'll only say about him uh that he's +probably the most various and gifted of + + align:start position:0% +probably the most various and gifted of + + + align:start position:0% +probably the most various and gifted of +all the of all the neorealist figures + + align:start position:0% +all the of all the neorealist figures + + + align:start position:0% +all the of all the neorealist figures +partly because he had been a very + + align:start position:0% +partly because he had been a very + + + align:start position:0% +partly because he had been a very +successful actor on uh before he became + + align:start position:0% +successful actor on uh before he became + + + align:start position:0% +successful actor on uh before he became +a director and I'll talk a bit more + + align:start position:0% +a director and I'll talk a bit more + + + align:start position:0% +a director and I'll talk a bit more +about Desa this evening what I want to + + align:start position:0% +about Desa this evening what I want to + + + align:start position:0% +about Desa this evening what I want to +illustrate now in the mo in the time we + + align:start position:0% +illustrate now in the mo in the time we + + + align:start position:0% +illustrate now in the mo in the time we +have left + + align:start position:0% +have left + + + align:start position:0% +have left +is an aspect of the neorealist aesthetic + + align:start position:0% +is an aspect of the neorealist aesthetic + + + align:start position:0% +is an aspect of the neorealist aesthetic +if we could use that term uh that I've + + align:start position:0% +if we could use that term uh that I've + + + align:start position:0% +if we could use that term uh that I've +talked about before when we discussed + + align:start position:0% +talked about before when we discussed + + + align:start position:0% +talked about before when we discussed +Renoir + + align:start position:0% +Renoir + + + align:start position:0% +Renoir +and that I implied in earlier comments + + align:start position:0% +and that I implied in earlier comments + + + align:start position:0% +and that I implied in earlier comments +that I made this afternoon it's what I + + align:start position:0% +that I made this afternoon it's what I + + + align:start position:0% +that I made this afternoon it's what I +call the neorealist + + align:start position:0% +call the neorealist + + + align:start position:0% +call the neorealist +counterplot and what by counterplot what + + align:start position:0% +counterplot and what by counterplot what + + + align:start position:0% +counterplot and what by counterplot what +I really want to call attention to are + + align:start position:0% +I really want to call attention to are + + + align:start position:0% +I really want to call attention to are +all those elements in the film that seem + + align:start position:0% +all those elements in the film that seem + + + align:start position:0% +all those elements in the film that seem +not + + align:start position:0% +not + + + align:start position:0% +not +to take part in the forward momentum of + + align:start position:0% +to take part in the forward momentum of + + + align:start position:0% +to take part in the forward momentum of +the story or what we might even think of + + align:start position:0% +the story or what we might even think of + + + align:start position:0% +the story or what we might even think of +them as retarding elements in which in + + align:start position:0% +them as retarding elements in which in + + + align:start position:0% +them as retarding elements in which in +which these films will sort of pause to + + align:start position:0% +which these films will sort of pause to + + + align:start position:0% +which these films will sort of pause to +smell the roses it's uh uh a version of + + align:start position:0% +smell the roses it's uh uh a version of + + + align:start position:0% +smell the roses it's uh uh a version of +what I mean of what I mean by this + + align:start position:0% +what I mean of what I mean by this + + + align:start position:0% +what I mean of what I mean by this +neorealist counterplot might be said to + + align:start position:0% +neorealist counterplot might be said to + + + align:start position:0% +neorealist counterplot might be said to +be embodied in that in that uh uh + + align:start position:0% +be embodied in that in that uh uh + + + align:start position:0% +be embodied in that in that uh uh +astonishing camera move we studied at + + align:start position:0% +astonishing camera move we studied at + + + align:start position:0% +astonishing camera move we studied at +the end of budoo save from drowning last + + align:start position:0% +the end of budoo save from drowning last + + + align:start position:0% +the end of budoo save from drowning last +week where the camera makes 180 degre + + align:start position:0% +week where the camera makes 180 degre + + + align:start position:0% +week where the camera makes 180 degre +swerve becomes interested in the beauty + + align:start position:0% +swerve becomes interested in the beauty + + + align:start position:0% +swerve becomes interested in the beauty +of the of the river becomes interested + + align:start position:0% +of the of the river becomes interested + + + align:start position:0% +of the of the river becomes interested +in the scenery almost as if it's + + align:start position:0% +in the scenery almost as if it's + + + align:start position:0% +in the scenery almost as if it's +forgotten its character right uh now + + align:start position:0% +forgotten its character right uh now + + + align:start position:0% +forgotten its character right uh now +what I mean by the counterplot is this + + align:start position:0% +what I mean by the counterplot is this + + + align:start position:0% +what I mean by the counterplot is this +impulse in these films and especially in + + align:start position:0% +impulse in these films and especially in + + + align:start position:0% +impulse in these films and especially in +these Italian films to uh to to + + align:start position:0% +these Italian films to uh to to + + + align:start position:0% +these Italian films to uh to to +uh complicate the social and political + + align:start position:0% +uh complicate the social and political + + + align:start position:0% +uh complicate the social and political +and even the psychological Pro processes + + align:start position:0% +and even the psychological Pro processes + + + align:start position:0% +and even the psychological Pro processes +of the story simply in order to give us + + align:start position:0% +of the story simply in order to give us + + + align:start position:0% +of the story simply in order to give us +a sense of what the experience it's + + align:start position:0% +a sense of what the experience it's + + + align:start position:0% +a sense of what the experience it's +describing is like as if it's a version + + align:start position:0% +describing is like as if it's a version + + + align:start position:0% +describing is like as if it's a version +of what I of what I'm interested in when + + align:start position:0% +of what I of what I'm interested in when + + + align:start position:0% +of what I of what I'm interested in when +I talk about how the camera can distract + + align:start position:0% +I talk about how the camera can distract + + + align:start position:0% +I talk about how the camera can distract +itself and one way I can illustrate what + + align:start position:0% +itself and one way I can illustrate what + + + align:start position:0% +itself and one way I can illustrate what +so so what I mean by counterplot then + + align:start position:0% +so so what I mean by counterplot then + + + align:start position:0% +so so what I mean by counterplot then +are energies that or slow down + + align:start position:0% +are energies that or slow down + + + align:start position:0% +are energies that or slow down +the basic the the basic story or that + + align:start position:0% +the basic the the basic story or that + + + align:start position:0% +the basic the the basic story or that +seem not to directly contribute to the + + align:start position:0% +seem not to directly contribute to the + + + align:start position:0% +seem not to directly contribute to the +basic story but are but but but remain + + align:start position:0% +basic story but are but but but remain + + + align:start position:0% +basic story but are but but but remain +part of the film's desire to represent + + align:start position:0% +part of the film's desire to represent + + + align:start position:0% +part of the film's desire to represent +the world to represent reality in + + align:start position:0% +the world to represent reality in + + + align:start position:0% +the world to represent reality in +something of its complexity in something + + align:start position:0% +something of its complexity in something + + + align:start position:0% +something of its complexity in something +of its Nuance even in something of its + + align:start position:0% +of its Nuance even in something of its + + + align:start position:0% +of its Nuance even in something of its +contradictory incoherence right in other + + align:start position:0% +contradictory incoherence right in other + + + align:start position:0% +contradictory incoherence right in other +words I don't really want to call these + + align:start position:0% +words I don't really want to call these + + + align:start position:0% +words I don't really want to call these +moments incoherent moments they're not + + align:start position:0% +moments incoherent moments they're not + + + align:start position:0% +moments incoherent moments they're not +because they build a much larger and + + align:start position:0% +because they build a much larger and + + + align:start position:0% +because they build a much larger and +more complete picture of the whole world + + align:start position:0% +more complete picture of the whole world + + + align:start position:0% +more complete picture of the whole world +you're looking at and in that sense + + align:start position:0% +you're looking at and in that sense + + + align:start position:0% +you're looking at and in that sense +they're not incoherent but but but they + + align:start position:0% +they're not incoherent but but but they + + + align:start position:0% +they're not incoherent but but but they +are a kind of counter to the ongoing + + align:start position:0% +are a kind of counter to the ongoing + + + align:start position:0% +are a kind of counter to the ongoing +pressure to find out what happens next + + align:start position:0% +pressure to find out what happens next + + + align:start position:0% +pressure to find out what happens next +what happens next what happens next well + + align:start position:0% +what happens next what happens next well + + + align:start position:0% +what happens next what happens next well +there are many many examples of this um + + align:start position:0% +there are many many examples of this um + + + align:start position:0% +there are many many examples of this um +uh principle in The Bicycle Thief and in + + align:start position:0% +uh principle in The Bicycle Thief and in + + + align:start position:0% +uh principle in The Bicycle Thief and in +other neorealist films but I want to + + align:start position:0% +other neorealist films but I want to + + + align:start position:0% +other neorealist films but I want to +show you one very dramatic one also to + + align:start position:0% +show you one very dramatic one also to + + + align:start position:0% +show you one very dramatic one also to +give you a a flavor for an earlier + + align:start position:0% +give you a a flavor for an earlier + + + align:start position:0% +give you a a flavor for an earlier +neorealist film other than the one + + align:start position:0% +neorealist film other than the one + + + align:start position:0% +neorealist film other than the one +you're going to see tonight this is from + + align:start position:0% +you're going to see tonight this is from + + + align:start position:0% +you're going to see tonight this is from +the very beginning of Open + + align:start position:0% +the very beginning of Open + + + align:start position:0% +the very beginning of Open +City + + align:start position:0% +City + + + align:start position:0% +City +great + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +for these are residents of Rome they've + + align:start position:0% +for these are residents of Rome they've + + + align:start position:0% +for these are residents of Rome they've +heard an explosion there's sabotage + + align:start position:0% +heard an explosion there's sabotage + + + align:start position:0% +heard an explosion there's sabotage +going on in Rome now it's near the end + + align:start position:0% +going on in Rome now it's near the end + + + align:start position:0% +going on in Rome now it's near the end +of the war where the war's not over and + + align:start position:0% +of the war where the war's not over and + + + align:start position:0% +of the war where the war's not over and +now the sabur return + + align:start position:0% +now the sabur return + + + align:start position:0% +now the sabur return +home and look who they turn out to + + align:start position:0% + + + + align:start position:0% + +be and of course that's why Anna manani + + align:start position:0% +be and of course that's why Anna manani + + + align:start position:0% +be and of course that's why Anna manani +was the actress was worried about where + + align:start position:0% +was the actress was worried about where + + + align:start position:0% +was the actress was worried about where +the children were because they + + align:start position:0% +the children were because they + + + align:start position:0% +the children were because they +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +suspected there's already a counterplot + + align:start position:0% +suspected there's already a counterplot + + + align:start position:0% +suspected there's already a counterplot +operating here I hope you see what look + + align:start position:0% +operating here I hope you see what look + + + align:start position:0% +operating here I hope you see what look +at these little innocent + + align:start position:0% + + + + align:start position:0% + +faces so these sabur have now come home + + align:start position:0% +faces so these sabur have now come home + + + align:start position:0% +faces so these sabur have now come home +watch + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +fore + + align:start position:0% +fore + + + align:start position:0% +fore +fore + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +foree + + align:start position:0% +foree + + + align:start position:0% +foree +foree + + align:start position:0% +foree + + + align:start position:0% +foree +speee spee spee + + align:start position:0% + + + + align:start position:0% + +foree + + align:start position:0% + + + + align:start position:0% + +fore + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +speee foree + + align:start position:0% +speee foree + + + align:start position:0% +speee foree +[Music] + + align:start position:0% + + + + align:start position:0% + +all right stop I'm stopping it a little + + align:start position:0% +all right stop I'm stopping it a little + + + align:start position:0% +all right stop I'm stopping it a little +early the scene continues you actually + + align:start position:0% +early the scene continues you actually + + + align:start position:0% +early the scene continues you actually +go into another room in a moment and you + + align:start position:0% +go into another room in a moment and you + + + align:start position:0% +go into another room in a moment and you +see children in a kind of dormatory like + + align:start position:0% +see children in a kind of dormatory like + + + align:start position:0% +see children in a kind of dormatory like +room in which there's one little child + + align:start position:0% +room in which there's one little child + + + align:start position:0% +room in which there's one little child +sitting on a potty and I think it's the + + align:start position:0% +sitting on a potty and I think it's the + + + align:start position:0% +sitting on a potty and I think it's the +first potty scene in Western film and + + align:start position:0% +first potty scene in Western film and + + + align:start position:0% +first potty scene in Western film and +they do something very disturbing too + + align:start position:0% +they do something very disturbing too + + + align:start position:0% +they do something very disturbing too +they pick him off the potty and put him + + align:start position:0% +they pick him off the potty and put him + + + align:start position:0% +they pick him off the potty and put him +back in bed without wiping him but leave + + align:start position:0% +back in bed without wiping him but leave + + + align:start position:0% +back in bed without wiping him but leave +the maybe there was no toilet paper in + + align:start position:0% +the maybe there was no toilet paper in + + + align:start position:0% +the maybe there was no toilet paper in +post-war Italy but uh I your laughter + + align:start position:0% +post-war Italy but uh I your laughter + + + align:start position:0% +post-war Italy but uh I your laughter +indicated to me that you sort of got the + + align:start position:0% +indicated to me that you sort of got the + + + align:start position:0% +indicated to me that you sort of got the +point but talk to me a little bit about + + align:start position:0% +point but talk to me a little bit about + + + align:start position:0% +point but talk to me a little bit about +what you see there I mean what it's a + + align:start position:0% +what you see there I mean what it's a + + + align:start position:0% +what you see there I mean what it's a +wonderful example of what I was trying + + align:start position:0% +wonderful example of what I was trying + + + align:start position:0% +wonderful example of what I was trying +to illustrate at the beginning as well + + align:start position:0% +to illustrate at the beginning as well + + + align:start position:0% +to illustrate at the beginning as well +this principle of Multiplicity what's + + align:start position:0% +this principle of Multiplicity what's + + + align:start position:0% +this principle of Multiplicity what's +happening in this sequence what what do + + align:start position:0% +happening in this sequence what what do + + + align:start position:0% +happening in this sequence what what do +we + + align:start position:0% +we + + + align:start position:0% +we +learn what about living conditions in + + align:start position:0% +learn what about living conditions in + + + align:start position:0% +learn what about living conditions in +what do we learn nobody gives a lecture + + align:start position:0% +what do we learn nobody gives a lecture + + + align:start position:0% +what do we learn nobody gives a lecture +about it what what you think there is a + + align:start position:0% +about it what what you think there is a + + + align:start position:0% +about it what what you think there is a +housing crisis in Rome seven families + + align:start position:0% +housing crisis in Rome seven families + + + align:start position:0% +housing crisis in Rome seven families +living together in the same room an old + + align:start position:0% +living together in the same room an old + + + align:start position:0% +living together in the same room an old +man in bed lying in a bed in the Parlor + + align:start position:0% +man in bed lying in a bed in the Parlor + + + align:start position:0% +man in bed lying in a bed in the Parlor +right in the in the space where the in + + align:start position:0% +right in the in the space where the in + + + align:start position:0% +right in the in the space where the in +the living space of the place right he's + + align:start position:0% +the living space of the place right he's + + + align:start position:0% +the living space of the place right he's +so that's clearly where he stays he's + + align:start position:0% +so that's clearly where he stays he's + + + align:start position:0% +so that's clearly where he stays he's +very ill right what + + align:start position:0% +very ill right what + + + align:start position:0% +very ill right what +else the deviation into comedy the + + align:start position:0% +else the deviation into comedy the + + + align:start position:0% +else the deviation into comedy the +extent right the mean the the extent to + + align:start position:0% +extent right the mean the the extent to + + + align:start position:0% +extent right the mean the the extent to +which a kind of a a kind of series of + + align:start position:0% +which a kind of a a kind of series of + + + align:start position:0% +which a kind of a a kind of series of +comic encounters occur after what after + + align:start position:0% +comic encounters occur after what after + + + align:start position:0% +comic encounters occur after what after +a moment of political sabotage right and + + align:start position:0% +a moment of political sabotage right and + + + align:start position:0% +a moment of political sabotage right and +the in congruity of these little + + align:start position:0% +the in congruity of these little + + + align:start position:0% +the in congruity of these little +children who are the ones who are the + + align:start position:0% +children who are the ones who are the + + + align:start position:0% +children who are the ones who are the +sabur is also part of the comedy even + + align:start position:0% +sabur is also part of the comedy even + + + align:start position:0% +sabur is also part of the comedy even +before we see them fully return to the + + align:start position:0% +before we see them fully return to the + + + align:start position:0% +before we see them fully return to the +condition of children when their parents + + align:start position:0% +condition of children when their parents + + + align:start position:0% +condition of children when their parents +start slapping them in there in the + + align:start position:0% +start slapping them in there in the + + + align:start position:0% +start slapping them in there in the +faces and saying how dare you stay out + + align:start position:0% +faces and saying how dare you stay out + + + align:start position:0% +faces and saying how dare you stay out +so late I didn't mean to suggest that + + align:start position:0% +so late I didn't mean to suggest that + + + align:start position:0% +so late I didn't mean to suggest that +the parents actually know that the + + align:start position:0% +the parents actually know that the + + + align:start position:0% +the parents actually know that the +children are sabur although although + + align:start position:0% +children are sabur although although + + + align:start position:0% +children are sabur although although +some may but I think the point is that + + align:start position:0% +some may but I think the point is that + + + align:start position:0% +some may but I think the point is that +being outside at night is very dangerous + + align:start position:0% +being outside at night is very dangerous + + + align:start position:0% +being outside at night is very dangerous +for little children children in this + + align:start position:0% +for little children children in this + + + align:start position:0% +for little children children in this +environment and that's why they're so + + align:start position:0% +environment and that's why they're so + + + align:start position:0% +environment and that's why they're so +concerned but they but but the fact that + + align:start position:0% +concerned but they but but the fact that + + + align:start position:0% +concerned but they but but the fact that +even the children are partisan + + align:start position:0% +even the children are partisan + + + align:start position:0% +even the children are partisan +anti-fascist Fighters becomes a part of + + align:start position:0% +anti-fascist Fighters becomes a part of + + + align:start position:0% +anti-fascist Fighters becomes a part of +what the film is about so the now you + + align:start position:0% +what the film is about so the now you + + + align:start position:0% +what the film is about so the now you +can't tell from the very beginning from + + align:start position:0% +can't tell from the very beginning from + + + align:start position:0% +can't tell from the very beginning from +this beginning what the real sort of uh + + align:start position:0% +this beginning what the real sort of uh + + + align:start position:0% +this beginning what the real sort of uh +plot energy of the film is yet can you + + align:start position:0% +plot energy of the film is yet can you + + + align:start position:0% +plot energy of the film is yet can you +uh and it will take a bit longer before + + align:start position:0% +uh and it will take a bit longer before + + + align:start position:0% +uh and it will take a bit longer before +it finally turns out the man that she's + + align:start position:0% +it finally turns out the man that she's + + + align:start position:0% +it finally turns out the man that she's +about to marry is a is a uh is a is a + + align:start position:0% +about to marry is a is a uh is a is a + + + align:start position:0% +about to marry is a is a uh is a is a +secret agent and he's been he's under + + align:start position:0% +secret agent and he's been he's under + + + align:start position:0% +secret agent and he's been he's under +he's he he's being he's being hunted by + + align:start position:0% +he's he he's being he's being hunted by + + + align:start position:0% +he's he he's being he's being hunted by +the fascist authorities and the film is + + align:start position:0% +the fascist authorities and the film is + + + align:start position:0% +the fascist authorities and the film is +about how he's how how the good Italians + + align:start position:0% +about how he's how how the good Italians + + + align:start position:0% +about how he's how how the good Italians +try to hide him uh uh but we don't learn + + align:start position:0% +try to hide him uh uh but we don't learn + + + align:start position:0% +try to hide him uh uh but we don't learn +that yet and I what what I want to + + align:start position:0% +that yet and I what what I want to + + + align:start position:0% +that yet and I what what I want to +suggest to you is something of life's + + align:start position:0% +suggest to you is something of life's + + + align:start position:0% +suggest to you is something of life's +variety something of life's comedy + + align:start position:0% +variety something of life's comedy + + + align:start position:0% +variety something of life's comedy +something of life's in congruity uh so + + align:start position:0% +something of life's in congruity uh so + + + align:start position:0% +something of life's in congruity uh so +uh emerges for us in those moments and + + align:start position:0% +uh emerges for us in those moments and + + + align:start position:0% +uh emerges for us in those moments and +it's what I want to call a counterplot + + align:start position:0% +it's what I want to call a counterplot + + + align:start position:0% +it's what I want to call a counterplot +because we take Delight in those moments + + align:start position:0% +because we take Delight in those moments + + + align:start position:0% +because we take Delight in those moments +we don't be impatient and say come on + + align:start position:0% +we don't be impatient and say come on + + + align:start position:0% +we don't be impatient and say come on +film tell me where you're going because + + align:start position:0% +film tell me where you're going because + + + align:start position:0% +film tell me where you're going because +what the film teaches us is that it's + + align:start position:0% +what the film teaches us is that it's + + + align:start position:0% +what the film teaches us is that it's +not in that narrow sense about plot at + + align:start position:0% +not in that narrow sense about plot at + + + align:start position:0% +not in that narrow sense about plot at +all + + align:start position:0% +all + + + align:start position:0% +all +but it's about life in its infinite + + align:start position:0% +but it's about life in its infinite + + + align:start position:0% +but it's about life in its infinite +complexity the greatest neorealist films + + align:start position:0% +complexity the greatest neorealist films + + + align:start position:0% +complexity the greatest neorealist films +Embrace this Principle as well as any + + align:start position:0% +Embrace this Principle as well as any + + + align:start position:0% +Embrace this Principle as well as any +films I've ever known and in addition + + align:start position:0% +films I've ever known and in addition + + + align:start position:0% +films I've ever known and in addition +they have a kind of moral Authority + + align:start position:0% +they have a kind of moral Authority + + + align:start position:0% +they have a kind of moral Authority +that's very rare I'm very jealous of + + align:start position:0% +that's very rare I'm very jealous of + + + align:start position:0% +that's very rare I'm very jealous of +those of you in this course who have + + align:start position:0% +those of you in this course who have + + + align:start position:0% +those of you in this course who have +never seen The Bicycle Thief because it + + align:start position:0% +never seen The Bicycle Thief because it + + + align:start position:0% +never seen The Bicycle Thief because it +is a remarkable film that I'm sure + + align:start position:0% +is a remarkable film that I'm sure + + + align:start position:0% +is a remarkable film that I'm sure +you'll remember for the rest of your + + align:start position:0% +you'll remember for the rest of your + + + align:start position:0% +you'll remember for the rest of your +lives I'll see you + + align:start position:0% + + + + align:start position:0% + +tonight for \ No newline at end of file diff --git a/GFoYtA6TmRA.txt b/GFoYtA6TmRA.txt new file mode 100644 index 0000000000000000000000000000000000000000..2505a803771ef8844ef63c86da5e3842b687dd1d --- /dev/null +++ b/GFoYtA6TmRA.txt @@ -0,0 +1,2451 @@ +align:start position:0% + +when I explain to people what my job is + + align:start position:0% +when I explain to people what my job is + + + align:start position:0% +when I explain to people what my job is +like I always say that I'm somewhere in + + align:start position:0% +like I always say that I'm somewhere in + + + align:start position:0% +like I always say that I'm somewhere in +between a chief executive of uh edtech + + align:start position:0% +between a chief executive of uh edtech + + + align:start position:0% +between a chief executive of uh edtech +startup and the faculty adviser to a + + align:start position:0% +startup and the faculty adviser to a + + + align:start position:0% +startup and the faculty adviser to a +high school AV club that has grown out + + align:start position:0% +high school AV club that has grown out + + + align:start position:0% +high school AV club that has grown out +of + + align:start position:0% +of + + + align:start position:0% +of +control that's exactly what your job is + + align:start position:0% +control that's exactly what your job is + + + align:start position:0% +control that's exactly what your job is +yes so it's a really kind of remarkable + + align:start position:0% +yes so it's a really kind of remarkable + + + align:start position:0% +yes so it's a really kind of remarkable +and creative space in in that + + align:start position:0% +and creative space in in that + + + align:start position:0% +and creative space in in that +right today on Chalk radio I'm talking + + align:start position:0% +right today on Chalk radio I'm talking + + + align:start position:0% +right today on Chalk radio I'm talking +with Christopher capizola senior + + align:start position:0% +with Christopher capizola senior + + + align:start position:0% +with Christopher capizola senior +associate Dean for open learning at MIT + + align:start position:0% +associate Dean for open learning at MIT + + + align:start position:0% +associate Dean for open learning at MIT +part of his job is to provide strategic + + align:start position:0% +part of his job is to provide strategic + + + align:start position:0% +part of his job is to provide strategic +direction for MIT open courseware but + + align:start position:0% +direction for MIT open courseware but + + + align:start position:0% +direction for MIT open courseware but +that's not his only role here at MIT I'm + + align:start position:0% +that's not his only role here at MIT I'm + + + align:start position:0% +that's not his only role here at MIT I'm +also a professor of History so I've been + + align:start position:0% +also a professor of History so I've been + + + align:start position:0% +also a professor of History so I've been +teaching here for about 20 years and I + + align:start position:0% +teaching here for about 20 years and I + + + align:start position:0% +teaching here for about 20 years and I +teach American history so I teach + + align:start position:0% +teach American history so I teach + + + align:start position:0% +teach American history so I teach +everything from you know the American + + align:start position:0% +everything from you know the American + + + align:start position:0% +everything from you know the American +Revolution all the way to what's + + align:start position:0% +Revolution all the way to what's + + + align:start position:0% +Revolution all the way to what's +happening in the news this week Chris + + align:start position:0% +happening in the news this week Chris + + + align:start position:0% +happening in the news this week Chris +sees his role at the helm of open + + align:start position:0% +sees his role at the helm of open + + + align:start position:0% +sees his role at the helm of open +learning as very well connected to his + + align:start position:0% +learning as very well connected to his + + + align:start position:0% +learning as very well connected to his +background as a professor of history and + + align:start position:0% +background as a professor of history and + + + align:start position:0% +background as a professor of history and +I found it fascinating how his knowledge + + align:start position:0% +I found it fascinating how his knowledge + + + align:start position:0% +I found it fascinating how his knowledge +of American History informs his vision + + align:start position:0% +of American History informs his vision + + + align:start position:0% +of American History informs his vision +for OC's + + align:start position:0% +for OC's + + + align:start position:0% +for OC's +future I'd like to draw on your + + align:start position:0% +future I'd like to draw on your + + + align:start position:0% +future I'd like to draw on your +expertise as a historian to you know + + align:start position:0% +expertise as a historian to you know + + + align:start position:0% +expertise as a historian to you know +think about ocw when it started you + + align:start position:0% +think about ocw when it started you + + + align:start position:0% +think about ocw when it started you +mentioned earlier that it was like kind + + align:start position:0% +mentioned earlier that it was like kind + + + align:start position:0% +mentioned earlier that it was like kind +of an audacious move in the early + + align:start position:0% +of an audacious move in the early + + + align:start position:0% +of an audacious move in the early +2000s and I'm wondering if you could + + align:start position:0% +2000s and I'm wondering if you could + + + align:start position:0% +2000s and I'm wondering if you could +draw a parallel pars to any other + + align:start position:0% +draw a parallel pars to any other + + + align:start position:0% +draw a parallel pars to any other +movements in history where people tried + + align:start position:0% +movements in history where people tried + + + align:start position:0% +movements in history where people tried +to do something differently they weren't + + align:start position:0% +to do something differently they weren't + + + align:start position:0% +to do something differently they weren't +sure what the outcome would be what they + + align:start position:0% +sure what the outcome would be what they + + + align:start position:0% +sure what the outcome would be what they +learned that could inform where we take + + align:start position:0% +learned that could inform where we take + + + align:start position:0% +learned that could inform where we take +ocw in the + + align:start position:0% +ocw in the + + + align:start position:0% +ocw in the +future so about 150 years ago between + + align:start position:0% +future so about 150 years ago between + + + align:start position:0% +future so about 150 years ago between +the 1870s and + + align:start position:0% +the 1870s and + + + align:start position:0% +the 1870s and +1890s the United States and the rest of + + align:start position:0% +1890s the United States and the rest of + + + align:start position:0% +1890s the United States and the rest of +the world went through an information + + align:start position:0% +the world went through an information + + + align:start position:0% +the world went through an information +revolution transformations in + + align:start position:0% +revolution transformations in + + + align:start position:0% +revolution transformations in +communication technologies that gave us + + align:start position:0% +communication technologies that gave us + + + align:start position:0% +communication technologies that gave us +things like the telegraph the telephone + + align:start position:0% +things like the telegraph the telephone + + + align:start position:0% +things like the telegraph the telephone +and Transformations also in information + + align:start position:0% +and Transformations also in information + + + align:start position:0% +and Transformations also in information +and Publishing new inventions + + align:start position:0% +and Publishing new inventions + + + align:start position:0% +and Publishing new inventions +photography right Mass photography um + + align:start position:0% +photography right Mass photography um + + + align:start position:0% +photography right Mass photography um +printing of newspapers and images the + + align:start position:0% +printing of newspapers and images the + + + align:start position:0% +printing of newspapers and images the +mass circulation of books you know cheap + + align:start position:0% +mass circulation of books you know cheap + + + align:start position:0% +mass circulation of books you know cheap +paperback books other things like that + + align:start position:0% +paperback books other things like that + + + align:start position:0% +paperback books other things like that +that people in the 1870s and ' 80s also + + align:start position:0% +that people in the 1870s and ' 80s also + + + align:start position:0% +that people in the 1870s and ' 80s also +lived in a world in which there were new + + align:start position:0% +lived in a world in which there were new + + + align:start position:0% +lived in a world in which there were new +possibilities for knowledge both its + + align:start position:0% +possibilities for knowledge both its + + + align:start position:0% +possibilities for knowledge both its +production and its dissemination and and + + align:start position:0% +production and its dissemination and and + + + align:start position:0% +production and its dissemination and and +new questions about the trustworthiness + + align:start position:0% +new questions about the trustworthiness + + + align:start position:0% +new questions about the trustworthiness +of what they were seeing and + + align:start position:0% +of what they were seeing and + + + align:start position:0% +of what they were seeing and +reading and also I think another key + + align:start position:0% +reading and also I think another key + + + align:start position:0% +reading and also I think another key +element of this is new technologies for + + align:start position:0% +element of this is new technologies for + + + align:start position:0% +element of this is new technologies for +organizing that information right um so + + align:start position:0% +organizing that information right um so + + + align:start position:0% +organizing that information right um so +I warned you I'm a history nerd right + + align:start position:0% +I warned you I'm a history nerd right + + + align:start position:0% +I warned you I'm a history nerd right +and so I'm going to tell you about a + + align:start position:0% +and so I'm going to tell you about a + + + align:start position:0% +and so I'm going to tell you about a +very nerdy moment in American history + + align:start position:0% +very nerdy moment in American history + + + align:start position:0% +very nerdy moment in American history +great um which is the invention of the + + align:start position:0% +great um which is the invention of the + + + align:start position:0% +great um which is the invention of the +Dewey Decimal System I love it in 1876 + + align:start position:0% +Dewey Decimal System I love it in 1876 + + + align:start position:0% +Dewey Decimal System I love it in 1876 +Melville Dewey who was a librarian at + + align:start position:0% +Melville Dewey who was a librarian at + + + align:start position:0% +Melville Dewey who was a librarian at +ammer College here in Massachusetts + + align:start position:0% +ammer College here in Massachusetts + + + align:start position:0% +ammer College here in Massachusetts +realized that the books in the library + + align:start position:0% +realized that the books in the library + + + align:start position:0% +realized that the books in the library +were just badly organized right and so + + align:start position:0% +were just badly organized right and so + + + align:start position:0% +were just badly organized right and so +he developed the Dewey Decimal System + + align:start position:0% +he developed the Dewey Decimal System + + + align:start position:0% +he developed the Dewey Decimal System +which many of us know from the + + align:start position:0% +which many of us know from the + + + align:start position:0% +which many of us know from the +elementary school library class but it's + + align:start position:0% +elementary school library class but it's + + + align:start position:0% +elementary school library class but it's +sort of the foundation of information + + align:start position:0% +sort of the foundation of information + + + align:start position:0% +sort of the foundation of information +science and it's a way of organizing + + align:start position:0% +science and it's a way of organizing + + + align:start position:0% +science and it's a way of organizing +knowledge at the same time another + + align:start position:0% +knowledge at the same time another + + + align:start position:0% +knowledge at the same time another +transformation is happening in libraries + + align:start position:0% +transformation is happening in libraries + + + align:start position:0% +transformation is happening in libraries +which is the Innovations of the carnegi + + align:start position:0% +which is the Innovations of the carnegi + + + align:start position:0% +which is the Innovations of the carnegi +library designed to bring books and + + align:start position:0% +library designed to bring books and + + + align:start position:0% +library designed to bring books and +knowledge to communities all around the + + align:start position:0% +knowledge to communities all around the + + + align:start position:0% +knowledge to communities all around the +country and so if we think about it we + + align:start position:0% +country and so if we think about it we + + + align:start position:0% +country and so if we think about it we +have technological innovation we have + + align:start position:0% +have technological innovation we have + + + align:start position:0% +have technological innovation we have +specific Innovations around information + + align:start position:0% +specific Innovations around information + + + align:start position:0% +specific Innovations around information +and knowledge + + align:start position:0% +and knowledge + + + align:start position:0% +and knowledge +organization and we have a critical role + + align:start position:0% +organization and we have a critical role + + + align:start position:0% +organization and we have a critical role +of Foundations and other players in + + align:start position:0% +of Foundations and other players in + + + align:start position:0% +of Foundations and other players in +democratizing that information now in + + align:start position:0% +democratizing that information now in + + + align:start position:0% +democratizing that information now in +the 1870s and ' 80s you know that didn't + + align:start position:0% +the 1870s and ' 80s you know that didn't + + + align:start position:0% +the 1870s and ' 80s you know that didn't +go far enough libraries particularly in + + align:start position:0% +go far enough libraries particularly in + + + align:start position:0% +go far enough libraries particularly in +the South were racially segregated those + + align:start position:0% +the South were racially segregated those + + + align:start position:0% +the South were racially segregated those +Technologies of information could + + align:start position:0% +Technologies of information could + + + align:start position:0% +Technologies of information could +sometimes be used as much to organize + + align:start position:0% +sometimes be used as much to organize + + + align:start position:0% +sometimes be used as much to organize +and discipline workers and ethnic groups + + align:start position:0% +and discipline workers and ethnic groups + + + align:start position:0% +and discipline workers and ethnic groups +as to share that knowledge but you know + + align:start position:0% +as to share that knowledge but you know + + + align:start position:0% +as to share that knowledge but you know +everything that we're going through + + align:start position:0% +everything that we're going through + + + align:start position:0% +everything that we're going through +right now we've been there + + align:start position:0% +right now we've been there + + + align:start position:0% +right now we've been there +before the lessons are that you know as + + align:start position:0% +before the lessons are that you know as + + + align:start position:0% +before the lessons are that you know as +with many other sort of technological + + align:start position:0% +with many other sort of technological + + + align:start position:0% +with many other sort of technological +innovations and also efforts to + + align:start position:0% +innovations and also efforts to + + + align:start position:0% +innovations and also efforts to +democratize + + align:start position:0% +democratize + + + align:start position:0% +democratize +Technologies is that we need to build in + + align:start position:0% +Technologies is that we need to build in + + + align:start position:0% +Technologies is that we need to build in +equity from the beginning that we need + + align:start position:0% +equity from the beginning that we need + + + align:start position:0% +equity from the beginning that we need +to be asking who are these for who are + + align:start position:0% +to be asking who are these for who are + + + align:start position:0% +to be asking who are these for who are +we trying to reach who are the users how + + align:start position:0% +we trying to reach who are the users how + + + align:start position:0% +we trying to reach who are the users how +do they guide us to share and preserve + + align:start position:0% +do they guide us to share and preserve + + + align:start position:0% +do they guide us to share and preserve +information in valuable and meaningful + + align:start position:0% +information in valuable and meaningful + + + align:start position:0% +information in valuable and meaningful +and Equitable ways so that's a lesson + + align:start position:0% +and Equitable ways so that's a lesson + + + align:start position:0% +and Equitable ways so that's a lesson +what this might tell us for where ocw + + align:start position:0% +what this might tell us for where ocw + + + align:start position:0% +what this might tell us for where ocw +should go next right is that we have + + align:start position:0% +should go next right is that we have + + + align:start position:0% +should go next right is that we have +challenges for how to preserve the + + align:start position:0% +challenges for how to preserve the + + + align:start position:0% +challenges for how to preserve the +massive amount of information that is + + align:start position:0% +massive amount of information that is + + + align:start position:0% +massive amount of information that is +generated on our campus every day + + align:start position:0% +generated on our campus every day + + + align:start position:0% +generated on our campus every day +thousands of hours of video thousands + + align:start position:0% +thousands of hours of video thousands + + + align:start position:0% +thousands of hours of video thousands +and thousands of pages of learning + + align:start position:0% +and thousands of pages of learning + + + align:start position:0% +and thousands of pages of learning +Beyond a lecture from a professor at the + + align:start position:0% +Beyond a lecture from a professor at the + + + align:start position:0% +Beyond a lecture from a professor at the +front of the room you know so much + + align:start position:0% +front of the room you know so much + + + align:start position:0% +front of the room you know so much +learning is happening in chat it's + + align:start position:0% +learning is happening in chat it's + + + align:start position:0% +learning is happening in chat it's +happening on the sidebars of of a class + + align:start position:0% +happening on the sidebars of of a class + + + align:start position:0% +happening on the sidebars of of a class +but we have to make it discoverable you + + align:start position:0% +but we have to make it discoverable you + + + align:start position:0% +but we have to make it discoverable you +know it's one thing to put a th000 hours + + align:start position:0% +know it's one thing to put a th000 hours + + + align:start position:0% +know it's one thing to put a th000 hours +of video online but but how can you find + + align:start position:0% +of video online but but how can you find + + + align:start position:0% +of video online but but how can you find +the 5 minutes that that you're + + align:start position:0% +the 5 minutes that that you're + + + align:start position:0% +the 5 minutes that that you're +interested in and we have to make it + + align:start position:0% +interested in and we have to make it + + + align:start position:0% +interested in and we have to make it +trustable we need not only to find the + + align:start position:0% +trustable we need not only to find the + + + align:start position:0% +trustable we need not only to find the +Andrew carnegies of today to support us + + align:start position:0% +Andrew carnegies of today to support us + + + align:start position:0% +Andrew carnegies of today to support us +to make it possible we need to find the + + align:start position:0% +to make it possible we need to find the + + + align:start position:0% +to make it possible we need to find the +Melville deys of today who can help us + + align:start position:0% +Melville deys of today who can help us + + + align:start position:0% +Melville deys of today who can help us +come up with you know the version of the + + align:start position:0% +come up with you know the version of the + + + align:start position:0% +come up with you know the version of the +Dewey Decimal System but the special + + align:start position:0% +Dewey Decimal System but the special + + + align:start position:0% +Dewey Decimal System but the special +challenge we face today is to make it + + align:start position:0% +challenge we face today is to make it + + + align:start position:0% +challenge we face today is to make it +trustworthy as you a listener of this + + align:start position:0% +trustworthy as you a listener of this + + + align:start position:0% +trustworthy as you a listener of this +show are probably already aware the core + + align:start position:0% +show are probably already aware the core + + + align:start position:0% +show are probably already aware the core +of OC's mission is making education open + + align:start position:0% +of OC's mission is making education open + + + align:start position:0% +of OC's mission is making education open +Equitable and available to the world in + + align:start position:0% +Equitable and available to the world in + + + align:start position:0% +Equitable and available to the world in +the age of generative AI products like + + align:start position:0% +the age of generative AI products like + + + align:start position:0% +the age of generative AI products like +chat GPT are bringing into question both + + align:start position:0% +chat GPT are bringing into question both + + + align:start position:0% +chat GPT are bringing into question both +what the future of Education looks looks + + align:start position:0% +what the future of Education looks looks + + + align:start position:0% +what the future of Education looks looks +like and how equitably it can be + + align:start position:0% +like and how equitably it can be + + + align:start position:0% +like and how equitably it can be +disseminated as he looks to OC's future + + align:start position:0% +disseminated as he looks to OC's future + + + align:start position:0% +disseminated as he looks to OC's future +I was curious how Chris imagines + + align:start position:0% +I was curious how Chris imagines + + + align:start position:0% +I was curious how Chris imagines +generative AI impacting For Better or + + align:start position:0% +generative AI impacting For Better or + + + align:start position:0% +generative AI impacting For Better or +For Worse teaching and learning some of + + align:start position:0% +For Worse teaching and learning some of + + + align:start position:0% +For Worse teaching and learning some of +the very first responses from Educators + + align:start position:0% +the very first responses from Educators + + + align:start position:0% +the very first responses from Educators +were defensive how do we shut it down + + align:start position:0% +were defensive how do we shut it down + + + align:start position:0% +were defensive how do we shut it down +and also distrustful of Learners right + + align:start position:0% +and also distrustful of Learners right + + + align:start position:0% +and also distrustful of Learners right +students are going to use it to cheat + + align:start position:0% +students are going to use it to cheat + + + align:start position:0% +students are going to use it to cheat +you know we all heard this right you + + align:start position:0% +you know we all heard this right you + + + align:start position:0% +you know we all heard this right you +know it's going to write the essays no + + align:start position:0% +know it's going to write the essays no + + + align:start position:0% +know it's going to write the essays no +one's ever going to write essay again + + align:start position:0% +one's ever going to write essay again + + + align:start position:0% +one's ever going to write essay again +Etc and being defensive and distrustful + + align:start position:0% +Etc and being defensive and distrustful + + + align:start position:0% +Etc and being defensive and distrustful +is usually not the best way to be a good + + align:start position:0% +is usually not the best way to be a good + + + align:start position:0% +is usually not the best way to be a good +teacher you know I feel like most + + align:start position:0% +teacher you know I feel like most + + + align:start position:0% +teacher you know I feel like most +instructors at MIT are in a sort of + + align:start position:0% +instructors at MIT are in a sort of + + + align:start position:0% +instructors at MIT are in a sort of +phase between trying to stop chat GPT + + align:start position:0% +phase between trying to stop chat GPT + + + align:start position:0% +phase between trying to stop chat GPT +and other tools um and completely + + align:start position:0% +and other tools um and completely + + + align:start position:0% +and other tools um and completely +embracing them right in between there's + + align:start position:0% +embracing them right in between there's + + + align:start position:0% +embracing them right in between there's +a a space of + + align:start position:0% +a a space of + + + align:start position:0% +a a space of +curiosity and that's I think where we'll + + align:start position:0% +curiosity and that's I think where we'll + + + align:start position:0% +curiosity and that's I think where we'll +be most productive obviously there are + + align:start position:0% +be most productive obviously there are + + + align:start position:0% +be most productive obviously there are +challenges us with academic Integrity + + align:start position:0% +challenges us with academic Integrity + + + align:start position:0% +challenges us with academic Integrity +that you know came up in the very first + + align:start position:0% +that you know came up in the very first + + + align:start position:0% +that you know came up in the very first +days after these products came to Market + + align:start position:0% +days after these products came to Market + + + align:start position:0% +days after these products came to Market +and for some of the other offerings we + + align:start position:0% +and for some of the other offerings we + + + align:start position:0% +and for some of the other offerings we +have in open learning the mitx courses + + align:start position:0% +have in open learning the mitx courses + + + align:start position:0% +have in open learning the mitx courses +and so forth um you know those + + align:start position:0% +and so forth um you know those + + + align:start position:0% +and so forth um you know those +conversations are are happening but + + align:start position:0% +conversations are are happening but + + + align:start position:0% +conversations are are happening but +those were already happening right and + + align:start position:0% +those were already happening right and + + + align:start position:0% +those were already happening right and +you know trying to figure out how + + align:start position:0% +you know trying to figure out how + + + align:start position:0% +you know trying to figure out how +to ensure that Learners use these tools + + align:start position:0% +to ensure that Learners use these tools + + + align:start position:0% +to ensure that Learners use these tools +to advance their learning rather than to + + align:start position:0% +to advance their learning rather than to + + + align:start position:0% +to advance their learning rather than to +shortcut it is it's not an enforcement + + align:start position:0% +shortcut it is it's not an enforcement + + + align:start position:0% +shortcut it is it's not an enforcement +game right it's actually it's a + + align:start position:0% +game right it's actually it's a + + + align:start position:0% +game right it's actually it's a +conversation it's an ongoing + + align:start position:0% +conversation it's an ongoing + + + align:start position:0% +conversation it's an ongoing +conversation you know and every every + + align:start position:0% +conversation you know and every every + + + align:start position:0% +conversation you know and every every +instructor is now going to be forced to + + align:start position:0% +instructor is now going to be forced to + + + align:start position:0% +instructor is now going to be forced to +spend more time explaining why they are + + align:start position:0% +spend more time explaining why they are + + + align:start position:0% +spend more time explaining why they are +making students do a task that's a good + + align:start position:0% +making students do a task that's a good + + + align:start position:0% +making students do a task that's a good +thing it's only going to make Learners + + align:start position:0% +thing it's only going to make Learners + + + align:start position:0% +thing it's only going to make Learners +more reflective of why they're + + align:start position:0% +more reflective of why they're + + + align:start position:0% +more reflective of why they're +learning what struck me about my + + align:start position:0% +learning what struck me about my + + + align:start position:0% +learning what struck me about my +conversation with Chris was how + + align:start position:0% +conversation with Chris was how + + + align:start position:0% +conversation with Chris was how +important it is in all of his work to + + align:start position:0% +important it is in all of his work to + + + align:start position:0% +important it is in all of his work to +spend time in this middle space of + + align:start position:0% +spend time in this middle space of + + + align:start position:0% +spend time in this middle space of +curiosity and reflectiveness that he + + align:start position:0% +curiosity and reflectiveness that he + + + align:start position:0% +curiosity and reflectiveness that he +talks about he explained how he creates + + align:start position:0% +talks about he explained how he creates + + + align:start position:0% +talks about he explained how he creates +an environment in which his students can + + align:start position:0% +an environment in which his students can + + + align:start position:0% +an environment in which his students can +engage in reflection it starts the + + align:start position:0% +engage in reflection it starts the + + + align:start position:0% +engage in reflection it starts the +moment they walk in the door my students + + align:start position:0% +moment they walk in the door my students + + + align:start position:0% +moment they walk in the door my students +find this very awkward at first right + + align:start position:0% +find this very awkward at first right + + + align:start position:0% +find this very awkward at first right +but you can't come into my class without + + align:start position:0% +but you can't come into my class without + + + align:start position:0% +but you can't come into my class without +saying + + align:start position:0% +saying + + + align:start position:0% +saying +hello and I might even shake your hand + + align:start position:0% +hello and I might even shake your hand + + + align:start position:0% +hello and I might even shake your hand +and you you have to know the names of + + align:start position:0% +and you you have to know the names of + + + align:start position:0% +and you you have to know the names of +every other student in the room right + + align:start position:0% +every other student in the room right + + + align:start position:0% +every other student in the room right +and I actually give a quiz sometimes to + + align:start position:0% +and I actually give a quiz sometimes to + + + align:start position:0% +and I actually give a quiz sometimes to +make sure that students know it right + + align:start position:0% +make sure that students know it right + + + align:start position:0% +make sure that students know it right +and and you know that's really just + + align:start position:0% +and and you know that's really just + + + align:start position:0% +and and you know that's really just +really basic + + align:start position:0% +really basic + + + align:start position:0% +really basic +crucial step to understanding that this + + align:start position:0% +crucial step to understanding that this + + + align:start position:0% +crucial step to understanding that this +is a collective Enterprise and not a + + align:start position:0% +is a collective Enterprise and not a + + + align:start position:0% +is a collective Enterprise and not a +spectator sport if you know the names of + + align:start position:0% +spectator sport if you know the names of + + + align:start position:0% +spectator sport if you know the names of +of everyone else in the room and if + + align:start position:0% +of everyone else in the room and if + + + align:start position:0% +of everyone else in the room and if +you've you know if you've said hello to + + align:start position:0% +you've you know if you've said hello to + + + align:start position:0% +you've you know if you've said hello to +all of them the tone just changes + + align:start position:0% +all of them the tone just changes + + + align:start position:0% +all of them the tone just changes +immediately you know I've have the Good + + align:start position:0% +immediately you know I've have the Good + + + align:start position:0% +immediately you know I've have the Good +Fortune at MIT of you know teaching + + align:start position:0% +Fortune at MIT of you know teaching + + + align:start position:0% +Fortune at MIT of you know teaching +small enough classes where we can do + + align:start position:0% +small enough classes where we can do + + + align:start position:0% +small enough classes where we can do +that Chris shared some strategies he + + align:start position:0% +that Chris shared some strategies he + + + align:start position:0% +that Chris shared some strategies he +uses to help students reflect on the + + align:start position:0% +uses to help students reflect on the + + + align:start position:0% +uses to help students reflect on the +complexities that have shaped decisions + + align:start position:0% +complexities that have shaped decisions + + + align:start position:0% +complexities that have shaped decisions +made throughout + + align:start position:0% +made throughout + + + align:start position:0% +made throughout +history I like to give them very sort + + align:start position:0% +history I like to give them very sort + + + align:start position:0% +history I like to give them very sort +of real world puzzle-based sort of + + align:start position:0% +of real world puzzle-based sort of + + + align:start position:0% +of real world puzzle-based sort of +problem-based moments of the past right + + align:start position:0% +problem-based moments of the past right + + + align:start position:0% +problem-based moments of the past right +where people were making decisions and + + align:start position:0% +where people were making decisions and + + + align:start position:0% +where people were making decisions and +they're not necessarily decisions about + + align:start position:0% +they're not necessarily decisions about + + + align:start position:0% +they're not necessarily decisions about +technology right they I generally don't + + align:start position:0% +technology right they I generally don't + + + align:start position:0% +technology right they I generally don't +teach that much about the history of + + align:start position:0% +teach that much about the history of + + + align:start position:0% +teach that much about the history of +specific + + align:start position:0% +specific + + + align:start position:0% +specific +Technologies um but where they might + + align:start position:0% +Technologies um but where they might + + + align:start position:0% +Technologies um but where they might +have been facing a a political choice + + align:start position:0% +have been facing a a political choice + + + align:start position:0% +have been facing a a political choice +right or a legal dilemma or a question + + align:start position:0% +right or a legal dilemma or a question + + + align:start position:0% +right or a legal dilemma or a question +of how to structure political economy in + + align:start position:0% +of how to structure political economy in + + + align:start position:0% +of how to structure political economy in +a moment and then make them realize just + + align:start position:0% +a moment and then make them realize just + + + align:start position:0% +a moment and then make them realize just +basically how complicated it is right + + align:start position:0% +basically how complicated it is right + + + align:start position:0% +basically how complicated it is right +and that I think can be very important + + align:start position:0% +and that I think can be very important + + + align:start position:0% +and that I think can be very important +to bear in mind in their own lives + + align:start position:0% +to bear in mind in their own lives + + + align:start position:0% +to bear in mind in their own lives +decades later when they're sort of + + align:start position:0% +decades later when they're sort of + + + align:start position:0% +decades later when they're sort of +confronting choices in their profession + + align:start position:0% +confronting choices in their profession + + + align:start position:0% +confronting choices in their profession +or in their political lives or whatever + + align:start position:0% +or in their political lives or whatever + + + align:start position:0% +or in their political lives or whatever +when they might have to realize oh it + + align:start position:0% +when they might have to realize oh it + + + align:start position:0% +when they might have to realize oh it +it's complicated yeah introducing + + align:start position:0% +it's complicated yeah introducing + + + align:start position:0% +it's complicated yeah introducing +complexity and recognizing that + + align:start position:0% +complexity and recognizing that + + + align:start position:0% +complexity and recognizing that +acknowledging it I think that's really + + align:start position:0% +acknowledging it I think that's really + + + align:start position:0% +acknowledging it I think that's really +important so especially in history like + + align:start position:0% +important so especially in history like + + + align:start position:0% +important so especially in history like +how do you create a classroom culture + + align:start position:0% +how do you create a classroom culture + + + align:start position:0% +how do you create a classroom culture +where people can express dissenting + + align:start position:0% +where people can express dissenting + + + align:start position:0% +where people can express dissenting +views you know take on challenging + + align:start position:0% +views you know take on challenging + + + align:start position:0% +views you know take on challenging +topics you know I can't + + align:start position:0% +topics you know I can't + + + align:start position:0% +topics you know I can't +say I've gotten it right every time and + + align:start position:0% +say I've gotten it right every time and + + + align:start position:0% +say I've gotten it right every time and +it's a moving Target as our culture + + align:start position:0% +it's a moving Target as our culture + + + align:start position:0% +it's a moving Target as our culture +shifts and as people come into class + + align:start position:0% +shifts and as people come into class + + + align:start position:0% +shifts and as people come into class +with different expectations um you know + + align:start position:0% +with different expectations um you know + + + align:start position:0% +with different expectations um you know +there's no one answer to these questions + + align:start position:0% +there's no one answer to these questions + + + align:start position:0% +there's no one answer to these questions +I think part of it + + align:start position:0% +I think part of it + + + align:start position:0% +I think part of it +is the importance + + align:start position:0% +is the importance + + + align:start position:0% +is the importance +of + + align:start position:0% +of + + + align:start position:0% +of +structured discussion which is to + + align:start position:0% +structured discussion which is to + + + align:start position:0% +structured discussion which is to +say + + align:start position:0% +say + + + align:start position:0% +say +before you state a position it's + + align:start position:0% +before you state a position it's + + + align:start position:0% +before you state a position it's +important to know what the what the + + align:start position:0% +important to know what the what the + + + align:start position:0% +important to know what the what the +landscape of possible positions is and + + align:start position:0% +landscape of possible positions is and + + + align:start position:0% +landscape of possible positions is and +to articulate them right and so + + align:start position:0% +to articulate them right and so + + + align:start position:0% +to articulate them right and so +encouraging students not just to know + + align:start position:0% +encouraging students not just to know + + + align:start position:0% +encouraging students not just to know +that there is a counterargument but + + align:start position:0% +that there is a counterargument but + + + align:start position:0% +that there is a counterargument but +actually to to state it and then they + + align:start position:0% +actually to to state it and then they + + + align:start position:0% +actually to to state it and then they +can navigate + + align:start position:0% +can navigate + + + align:start position:0% +can navigate +where they fit within + + align:start position:0% +where they fit within + + + align:start position:0% +where they fit within +that it was inspiring to hear how Chris + + align:start position:0% +that it was inspiring to hear how Chris + + + align:start position:0% +that it was inspiring to hear how Chris +infuses the values of reflectiveness and + + align:start position:0% +infuses the values of reflectiveness and + + + align:start position:0% +infuses the values of reflectiveness and +openness not just into his teaching but + + align:start position:0% +openness not just into his teaching but + + + align:start position:0% +openness not just into his teaching but +also into our work here at MIT open + + align:start position:0% +also into our work here at MIT open + + + align:start position:0% +also into our work here at MIT open +courseware there are plenty of + + align:start position:0% +courseware there are plenty of + + + align:start position:0% +courseware there are plenty of +researchers at MIT who would love if a + + align:start position:0% +researchers at MIT who would love if a + + + align:start position:0% +researchers at MIT who would love if a +few million more people understood what + + align:start position:0% +few million more people understood what + + + align:start position:0% +few million more people understood what +they did every day and you know open + + align:start position:0% +they did every day and you know open + + + align:start position:0% +they did every day and you know open +courseware can play a really kind of + + align:start position:0% +courseware can play a really kind of + + + align:start position:0% +courseware can play a really kind of +crucial role in making that possible we + + align:start position:0% +crucial role in making that possible we + + + align:start position:0% +crucial role in making that possible we +have a special role to play in in + + align:start position:0% +have a special role to play in in + + + align:start position:0% +have a special role to play in in +translating it and in part by feeding + + align:start position:0% +translating it and in part by feeding + + + align:start position:0% +translating it and in part by feeding +back to the MIT Community what Learners + + align:start position:0% +back to the MIT Community what Learners + + + align:start position:0% +back to the MIT Community what Learners +on open courseware are curious about + + align:start position:0% +on open courseware are curious about + + + align:start position:0% +on open courseware are curious about +what they're hungry to know about and at + + align:start position:0% +what they're hungry to know about and at + + + align:start position:0% +what they're hungry to know about and at +at what level of technical rigor and + + align:start position:0% +at what level of technical rigor and + + + align:start position:0% +at what level of technical rigor and +scientific Advance they can follow it + + align:start position:0% +scientific Advance they can follow it + + + align:start position:0% +scientific Advance they can follow it +we've actually only begun to imagine + + align:start position:0% +we've actually only begun to imagine + + + align:start position:0% +we've actually only begun to imagine +what's possible in those spaces and I + + align:start position:0% +what's possible in those spaces and I + + + align:start position:0% +what's possible in those spaces and I +think it's less in the delivery of + + align:start position:0% +think it's less in the delivery of + + + align:start position:0% +think it's less in the delivery of +content and more in the meaningfulness + + align:start position:0% +content and more in the meaningfulness + + + align:start position:0% +content and more in the meaningfulness +and authenticity of the actual learning + + align:start position:0% +and authenticity of the actual learning + + + align:start position:0% +and authenticity of the actual learning +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +experience that was Chris Capa professor + + align:start position:0% +experience that was Chris Capa professor + + + align:start position:0% +experience that was Chris Capa professor +of history and Senior associate Dean for + + align:start position:0% +of history and Senior associate Dean for + + + align:start position:0% +of history and Senior associate Dean for +open learning at MIT in addition to + + align:start position:0% +open learning at MIT in addition to + + + align:start position:0% +open learning at MIT in addition to +providing strategic direction for MIT + + align:start position:0% +providing strategic direction for MIT + + + align:start position:0% +providing strategic direction for MIT +open courseware he's also contributed + + align:start position:0% +open courseware he's also contributed + + + align:start position:0% +open courseware he's also contributed +materials from three of his courses to + + align:start position:0% +materials from three of his courses to + + + align:start position:0% +materials from three of his courses to +the ocw collection on our website you + + align:start position:0% +the ocw collection on our website you + + + align:start position:0% +the ocw collection on our website you +can find syllabi readings assignments + + align:start position:0% +can find syllabi readings assignments + + + align:start position:0% +can find syllabi readings assignments +and other resources from 21h 221 the + + align:start position:0% +and other resources from 21h 221 the + + + align:start position:0% +and other resources from 21h 221 the +places of migration in United States + + align:start position:0% +places of migration in United States + + + align:start position:0% +places of migration in United States +history 21 h223 war in American society + + align:start position:0% +history 21 h223 war in American society + + + align:start position:0% +history 21 h223 war in American society +and 21 h224 law and Society in US + + align:start position:0% +and 21 h224 law and Society in US + + + align:start position:0% +and 21 h224 law and Society in US +history we'll put the links to these + + align:start position:0% +history we'll put the links to these + + + align:start position:0% +history we'll put the links to these +courses in the show notes for you thank + + align:start position:0% +courses in the show notes for you thank + + + align:start position:0% +courses in the show notes for you thank +you so much for listening until next + + align:start position:0% +you so much for listening until next + + + align:start position:0% +you so much for listening until next +time signing off from Cambridge + + align:start position:0% +time signing off from Cambridge + + + align:start position:0% +time signing off from Cambridge +Massachusetts I'm your host Sarah Hansen + + align:start position:0% +Massachusetts I'm your host Sarah Hansen + + + align:start position:0% +Massachusetts I'm your host Sarah Hansen +from MIT open + + align:start position:0% +from MIT open + + + align:start position:0% +from MIT open +courseware MIT chalk radio's producers + + align:start position:0% +courseware MIT chalk radio's producers + + + align:start position:0% +courseware MIT chalk radio's producers +include myself red Pachi and Dave Lansky + + align:start position:0% +include myself red Pachi and Dave Lansky + + + align:start position:0% +include myself red Pachi and Dave Lansky +show notes for this episode were written + + align:start position:0% +show notes for this episode were written + + + align:start position:0% +show notes for this episode were written +by Peter Chipman Chris capa's ocw cor + + align:start position:0% +by Peter Chipman Chris capa's ocw cor + + + align:start position:0% +by Peter Chipman Chris capa's ocw cor +sites were built by Rees Jenkins Jason + + align:start position:0% +sites were built by Rees Jenkins Jason + + + align:start position:0% +sites were built by Rees Jenkins Jason +player made our episode cassette + + align:start position:0% +player made our episode cassette + + + align:start position:0% +player made our episode cassette +animation on YouTube We're funded by MIT + + align:start position:0% +animation on YouTube We're funded by MIT + + + align:start position:0% +animation on YouTube We're funded by MIT +open learning and supporters like you \ No newline at end of file diff --git a/Ht_tyuAWmpM.txt b/Ht_tyuAWmpM.txt new file mode 100644 index 0000000000000000000000000000000000000000..e83bc40e0cdd5a4616ebb95880ae3af8c3a5edd1 --- /dev/null +++ b/Ht_tyuAWmpM.txt @@ -0,0 +1,218 @@ +Earlier we talked about about finding equivalent +FSMs with fewer states. + +Now we'll develop an approach for finding +such FSMs by looking for two states that that + +can be merged into a single state without +changing the behavior of the FSM in any externally + +distinguishable manner. + +Two states are equivalent if they meet the +following two criteria. + +First, the states must have identical outputs. + +This makes sense: the outputs are visible +to the outside, so if their values differed + +between the two states, that difference would +clearly be externally distinguishable! + +Second, for each combination of input values, +the two states transition to equivalent states. + +Our strategy for deriving an equivalent machine +with fewer states will be to start with our + +original FSM, find pairs of equivalent states +and merge those states. + +We'll keep repeating the process until we +can't find any more equivalent states. + +Let's try this on our ant FSM. + +First we need to find a pair of states that +have the same outputs. + +As it turns out, there's only one such pair: +WALL1 and CORNER, both of which assert the + +turn-right and forward outputs. + +Okay, so let's assume that WALL1 and CORNER +are equivalent and ask if they transition + +to equivalent states for each applicable combination +of input values. + +For these two states, all the transitions +depend only on the value of the R input, so + +we just have to check two cases. + +If R is 0, both states transition to CORNER. + +If R is 1, both states transition to WALL2. + +So both equivalence criteria are satisfied +and we can conclude that the WALL1 and CORNER + +states are equivalent and can be merged. + +This gives us the four-state FSM shown here, +where we've called the single merged state + +WALL1. + +This smaller, equivalent FSM behaves exactly +as the previous 5-state FSM. + +The implementation of the 5-state machine +requires 3 state bits; the implementation + +of the 4-state machine only requires 2 state +bits. + +Reducing the number of state bits by 1 is +huge since it reduces the size of the required + +ROM by half! + +Just as we were able to achieve considerable +hardware savings by minimizing Boolean equations, + +we can do the same in sequential logic by +merging equivalent states. + +Roboant customers are looking forward to the +price cut! + +Let's look at what we'd need to do if we wanted +to implement the FSM using logic gates instead + +a ROM for the combinational logic. + +First we have to build the truth table, entering +all the transitions in the state transition + +diagram. + +We'll start with the LOST state. + +So if the FSM is in this state, the F output +should be 1. + +If both antenna inputs are 0, the next state +is also LOST. + +Assigning the LOST state the encoding 00, +we've captured this information in the first + +row of the table. + +If either antenna is touching, the FSM should +transition from LOST to the rotate-counterclockwise + +state. + +We've given this an encoding of 01. + +There are three combinations of L and R values +that match this transition, so we've added + +three rows to the truth table. + +This takes care of all the transitions from +the LOST state. + +Now we can tackle the transitions from the +rotate-counterclockwise state. + +If either antenna is touching, the next state +is again rotate-counterclockwise. + +So we've identified the matching values for +the inputs and added the appropriate three + +rows to the transition table. + +We can continue in a similar manner to encode +the transitions one-by-one. + +Here's the final table, where we've used don't +cares to reduce the number of rows for presentation. + +Next we want to come up with Boolean equations +for each of the outputs of the combinational + +logic, i.e., the two next-state bits and the +three motion-control outputs. + +Here are the Karnaugh maps for the two next-state +bits. + +Using our K-map skills from Chapter 4, we'll +find a cover of the prime implicants for S1-prime + +and write down the corresponding product terms +in a minimal sum-of-products equation. + +And then do the same for the other next-state +bit. + +We can follow a similar process to derive +minimal sum-of-products expressions for the + +motion-control outputs. + +Implementing each sum-of-products in a straight-forward +fashion with AND and OR gates, we get the + +following schematic for the ant brain. + +Pretty neat! + +Who knew that maze following behavior could +be implemented with a couple of D registers + +and a handful of logic gates? + +There are many complex behaviors that can +be created with surprisingly simple FSMs. + +Early on, the computer graphics folks learned +that group behaviors like swarming, flocking + +and schooling can be modeled by equipping +each participant with a simple FSM. + +So next time you see the massive battle scene +from the Lord of the Rings movie, think of + +many FSMs running in parallel! + +Physical behaviors that arise from simple +interactions between component molecules can + +sometimes be more easily modeled using cellular +automata - + +arrays of communicating FSMS - than by trying +to solve the partial differential equations + +that model the constraints on the molecules' +behavior. + +And here's an idea: what if we allowed the +FSM to modify its own transition table? + +Hmm. + +Maybe that's a plausible model for evolution! + +FSMs are everywhere! + +You'll see FSMs for the rest of your life… \ No newline at end of file diff --git a/Ih4s5IFphCw.txt b/Ih4s5IFphCw.txt new file mode 100644 index 0000000000000000000000000000000000000000..439413d49b1c888ca521e3f117298b37d273e358 --- /dev/null +++ b/Ih4s5IFphCw.txt @@ -0,0 +1,7930 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +view additional materials from hundreds + + align:start position:0% +view additional materials from hundreds + + + align:start position:0% +view additional materials from hundreds +of MIT courses visit MIT opencourseware + + align:start position:0% +of MIT courses visit MIT opencourseware + + + align:start position:0% +of MIT courses visit MIT opencourseware +at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu hello and + + align:start position:0% + + + + align:start position:0% + +welcome so today I want to start to talk + + align:start position:0% +welcome so today I want to start to talk + + + align:start position:0% +welcome so today I want to start to talk +about discreet time + + align:start position:0% +about discreet time + + + align:start position:0% +about discreet time +systems but before beginning there I + + align:start position:0% +systems but before beginning there I + + + align:start position:0% +systems but before beginning there I +want to say just a quick word about + + align:start position:0% +want to say just a quick word about + + + align:start position:0% +want to say just a quick word about +homework I tried to stress this last + + align:start position:0% +homework I tried to stress this last + + + align:start position:0% +homework I tried to stress this last +time that the way you get to know this + + align:start position:0% +time that the way you get to know this + + + align:start position:0% +time that the way you get to know this +stuff is by doing the + + align:start position:0% +stuff is by doing the + + + align:start position:0% +stuff is by doing the +homework and we'd like to provide + + align:start position:0% +homework and we'd like to provide + + + align:start position:0% +homework and we'd like to provide +positive feedback in a direction that + + align:start position:0% +positive feedback in a direction that + + + align:start position:0% +positive feedback in a direction that +will help you get the most out of the + + align:start position:0% +will help you get the most out of the + + + align:start position:0% +will help you get the most out of the +homework so to that end we've already + + align:start position:0% +homework so to that end we've already + + + align:start position:0% +homework so to that end we've already +talked about there's two kinds of + + align:start position:0% +talked about there's two kinds of + + + align:start position:0% +talked about there's two kinds of +problems each homework will have tutor + + align:start position:0% +problems each homework will have tutor + + + align:start position:0% +problems each homework will have tutor +problems that are intended to be + + align:start position:0% +problems that are intended to be + + + align:start position:0% +problems that are intended to be +problems like you will see on an exam + + align:start position:0% +problems like you will see on an exam + + + align:start position:0% +problems like you will see on an exam +but they will also have the feature that + + align:start position:0% +but they will also have the feature that + + + align:start position:0% +but they will also have the feature that +they can be automatically graded so that + + align:start position:0% +they can be automatically graded so that + + + align:start position:0% +they can be automatically graded so that +you can get immediate + + align:start position:0% +you can get immediate + + + align:start position:0% +you can get immediate +feedback about whether you're doing it + + align:start position:0% +feedback about whether you're doing it + + + align:start position:0% +feedback about whether you're doing it +right or + + align:start position:0% +right or + + + align:start position:0% +right or +not there also be harder questions + + align:start position:0% +not there also be harder questions + + + align:start position:0% +not there also be harder questions +questions that look more like real world + + align:start position:0% +questions that look more like real world + + + align:start position:0% +questions that look more like real world +questions so you don't think that this + + align:start position:0% +questions so you don't think that this + + + align:start position:0% +questions so you don't think that this +class is only about toy + + align:start position:0% +class is only about toy + + + align:start position:0% +class is only about toy +problems the idea is to give you + + align:start position:0% +problems the idea is to give you + + + align:start position:0% +problems the idea is to give you +problems that you can imagine running + + align:start position:0% +problems that you can imagine running + + + align:start position:0% +problems that you can imagine running +into those are harder to grade + + align:start position:0% +into those are harder to grade + + + align:start position:0% +into those are harder to grade +automatically so we + + align:start position:0% +automatically so we + + + align:start position:0% +automatically so we +won't instead they'll be graded by a + + align:start position:0% +won't instead they'll be graded by a + + + align:start position:0% +won't instead they'll be graded by a +human that those problems often admit + + align:start position:0% +human that those problems often admit + + + align:start position:0% +human that those problems often admit +several different lines of reasoning so + + align:start position:0% +several different lines of reasoning so + + + align:start position:0% +several different lines of reasoning so +there isn't necessarily a unique right + + align:start position:0% +there isn't necessarily a unique right + + + align:start position:0% +there isn't necessarily a unique right +way to think about + + align:start position:0% +way to think about + + + align:start position:0% +way to think about +it so what we would like to do is + + align:start position:0% +it so what we would like to do is + + + align:start position:0% +it so what we would like to do is +encourage you to after you finish the + + align:start position:0% +encourage you to after you finish the + + + align:start position:0% +encourage you to after you finish the +homework read the + + align:start position:0% +homework read the + + + align:start position:0% +homework read the +solutions now we think it's kind of an + + align:start position:0% +solutions now we think it's kind of an + + + align:start position:0% +solutions now we think it's kind of an +impediment to wait for a week till you + + align:start position:0% +impediment to wait for a week till you + + + align:start position:0% +impediment to wait for a week till you +get your graded homework back because + + align:start position:0% +get your graded homework back because + + + align:start position:0% +get your graded homework back because +people in my experience just don't + + align:start position:0% +people in my experience just don't + + + align:start position:0% +people in my experience just don't +bother so what we would like to do is + + align:start position:0% +bother so what we would like to do is + + + align:start position:0% +bother so what we would like to do is +post the solutions immediately after the + + align:start position:0% +post the solutions immediately after the + + + align:start position:0% +post the solutions immediately after the +your Solutions are due your Solutions + + align:start position:0% +your Solutions are due your Solutions + + + align:start position:0% +your Solutions are due your Solutions +are due if you submit electronically at + + align:start position:0% +are due if you submit electronically at + + + align:start position:0% +are due if you submit electronically at +5:00 pm on the due date so homework one + + align:start position:0% +5:00 pm on the due date so homework one + + + align:start position:0% +5:00 pm on the due date so homework one +is due tomorrow 5:00 p.m electronic + + align:start position:0% +is due tomorrow 5:00 p.m electronic + + + align:start position:0% +is due tomorrow 5:00 p.m electronic +submission okay you can also turn in + + align:start position:0% +submission okay you can also turn in + + + align:start position:0% +submission okay you can also turn in +paper but you have to do that in your + + align:start position:0% +paper but you have to do that in your + + + align:start position:0% +paper but you have to do that in your +recitation immediately after it was due + + align:start position:0% +recitation immediately after it was due + + + align:start position:0% +recitation immediately after it was due +at 5:00 pm we'll post the + + align:start position:0% +at 5:00 pm we'll post the + + + align:start position:0% +at 5:00 pm we'll post the +solutions and we'll encourage you in + + align:start position:0% +solutions and we'll encourage you in + + + align:start position:0% +solutions and we'll encourage you in +quotes to read them + + align:start position:0% +quotes to read them + + + align:start position:0% +quotes to read them +because it's good for you right we hope + + align:start position:0% +because it's good for you right we hope + + + align:start position:0% +because it's good for you right we hope +that that will help you find the errors + + align:start position:0% +that that will help you find the errors + + + align:start position:0% +that that will help you find the errors +that you made but also expose you to + + align:start position:0% +that you made but also expose you to + + + align:start position:0% +that you made but also expose you to +other ways that maybe will be simpler + + align:start position:0% +other ways that maybe will be simpler + + + align:start position:0% +other ways that maybe will be simpler +maybe will be harder your feedback on + + align:start position:0% +maybe will be harder your feedback on + + + align:start position:0% +maybe will be harder your feedback on +you're coming up with a simpler way it + + align:start position:0% +you're coming up with a simpler way it + + + align:start position:0% +you're coming up with a simpler way it +would be greatly appreciated so please + + align:start position:0% +would be greatly appreciated so please + + + align:start position:0% +would be greatly appreciated so please +send me email anytime you think you have + + align:start position:0% +send me email anytime you think you have + + + align:start position:0% +send me email anytime you think you have +a better way of doing things which is + + align:start position:0% +a better way of doing things which is + + + align:start position:0% +a better way of doing things which is +entirely + + align:start position:0% +entirely + + + align:start position:0% +entirely +possible but as further encouragement if + + align:start position:0% +possible but as further encouragement if + + + align:start position:0% +possible but as further encouragement if +you mark up all of your errors and + + align:start position:0% +you mark up all of your errors and + + + align:start position:0% +you mark up all of your errors and +resubmit we'll give you back half the + + align:start position:0% +resubmit we'll give you back half the + + + align:start position:0% +resubmit we'll give you back half the +points you + + align:start position:0% +points you + + + align:start position:0% +points you +lost okay so you get to submit every + + align:start position:0% +lost okay so you get to submit every + + + align:start position:0% +lost okay so you get to submit every +homework twice once for the due date + + align:start position:0% +homework twice once for the due date + + + align:start position:0% +homework twice once for the due date +5:00 p.m. on + + align:start position:0% +5:00 p.m. on + + + align:start position:0% +5:00 p.m. on +Wednesday immediately after that you'll + + align:start position:0% +Wednesday immediately after that you'll + + + align:start position:0% +Wednesday immediately after that you'll +be able to see the published Solutions + + align:start position:0% +be able to see the published Solutions + + + align:start position:0% +be able to see the published Solutions +you can Circle all the errors and say + + align:start position:0% +you can Circle all the errors and say + + + align:start position:0% +you can Circle all the errors and say +algebra or conceptual or I'm an idiot or + + align:start position:0% +algebra or conceptual or I'm an idiot or + + + align:start position:0% +algebra or conceptual or I'm an idiot or +whatever is the right way of thinking + + align:start position:0% +whatever is the right way of thinking + + + align:start position:0% +whatever is the right way of thinking +about what you + + align:start position:0% +about what you + + + align:start position:0% +about what you +did and if you get all of the errors + + align:start position:0% +did and if you get all of the errors + + + align:start position:0% +did and if you get all of the errors +you'll get back half of the points you + + align:start position:0% +you'll get back half of the points you + + + align:start position:0% +you'll get back half of the points you +lost okay if you say I'm right you're + + align:start position:0% +lost okay if you say I'm right you're + + + align:start position:0% +lost okay if you say I'm right you're +wrong uh maybe you won't get all your + + align:start position:0% +wrong uh maybe you won't get all your + + + align:start position:0% +wrong uh maybe you won't get all your +points back + + align:start position:0% + + + + align:start position:0% + +yes uh the the resubmission is the same + + align:start position:0% +yes uh the the resubmission is the same + + + align:start position:0% +yes uh the the resubmission is the same +rules if you want to submit by paper you + + align:start position:0% +rules if you want to submit by paper you + + + align:start position:0% +rules if you want to submit by paper you +can turn them in on Friday's recitation + + align:start position:0% +can turn them in on Friday's recitation + + + align:start position:0% +can turn them in on Friday's recitation +you have until Friday at P 5: PM + + align:start position:0% +you have until Friday at P 5: PM + + + align:start position:0% +you have until Friday at P 5: PM +otherwise please notice that you're if + + align:start position:0% +otherwise please notice that you're if + + + align:start position:0% +otherwise please notice that you're if +you're using paper we will not have + + align:start position:0% +you're using paper we will not have + + + align:start position:0% +you're using paper we will not have +returned your + + align:start position:0% +returned your + + + align:start position:0% +returned your +Solutions in time for you to write on + + align:start position:0% +Solutions in time for you to write on + + + align:start position:0% +Solutions in time for you to write on +them + + align:start position:0% +them + + + align:start position:0% +them +so make a + + align:start position:0% +so make a + + + align:start position:0% +so make a +copy so if you want to do the paper + + align:start position:0% +copy so if you want to do the paper + + + align:start position:0% +copy so if you want to do the paper +route make a photo copy before you turn + + align:start position:0% +route make a photo copy before you turn + + + align:start position:0% +route make a photo copy before you turn +it in the first time so that you have + + align:start position:0% +it in the first time so that you have + + + align:start position:0% +it in the first time so that you have +something to write on for the second + + align:start position:0% +something to write on for the second + + + align:start position:0% +something to write on for the second +time if you submit electronically + + align:start position:0% +time if you submit electronically + + + align:start position:0% +time if you submit electronically +there's a feedback button on the on the + + align:start position:0% +there's a feedback button on the on the + + + align:start position:0% +there's a feedback button on the on the +tutor so you can see the thing that you + + align:start position:0% +tutor so you can see the thing that you + + + align:start position:0% +tutor so you can see the thing that you +just submitted so that's not a problem + + align:start position:0% +just submitted so that's not a problem + + + align:start position:0% +just submitted so that's not a problem +if you're doing the electronic thing but + + align:start position:0% +if you're doing the electronic thing but + + + align:start position:0% +if you're doing the electronic thing but +if you're doing paper please uh make a + + align:start position:0% +if you're doing paper please uh make a + + + align:start position:0% +if you're doing paper please uh make a +photo copy before you submit otherwise + + align:start position:0% +photo copy before you submit otherwise + + + align:start position:0% +photo copy before you submit otherwise +it will be hard to mark up your + + align:start position:0% +it will be hard to mark up your + + + align:start position:0% +it will be hard to mark up your +Solutions yes + + align:start position:0% + + + + align:start position:0% + +yes no but you should probably tell us + + align:start position:0% +yes no but you should probably tell us + + + align:start position:0% +yes no but you should probably tell us +what you'd like us to do we would + + align:start position:0% +what you'd like us to do we would + + + align:start position:0% +what you'd like us to do we would +normally try to make our best guess so + + align:start position:0% +normally try to make our best guess so + + + align:start position:0% +normally try to make our best guess so +if you turn in everything in the paper + + align:start position:0% +if you turn in everything in the paper + + + align:start position:0% +if you turn in everything in the paper +copy we will look at your previous + + align:start position:0% +copy we will look at your previous + + + align:start position:0% +copy we will look at your previous +submissions but it would be best if you + + align:start position:0% +submissions but it would be best if you + + + align:start position:0% +submissions but it would be best if you +said some remark like this overrides the + + align:start position:0% +said some remark like this overrides the + + + align:start position:0% +said some remark like this overrides the +electronic submission or please ignore + + align:start position:0% +electronic submission or please ignore + + + align:start position:0% +electronic submission or please ignore +problems one to + + align:start position:0% +problems one to + + + align:start position:0% +problems one to +four just make sure we know we're going + + align:start position:0% +four just make sure we know we're going + + + align:start position:0% +four just make sure we know we're going +to try to do what you want us to + + align:start position:0% +to try to do what you want us to + + + align:start position:0% +to try to do what you want us to +do other issues about logistics yes so + + align:start position:0% +do other issues about logistics yes so + + + align:start position:0% +do other issues about logistics yes so +just to make sure + + align:start position:0% +just to make sure + + + align:start position:0% +just to make sure +it's we don't have to submit homework + + align:start position:0% +it's we don't have to submit homework + + + align:start position:0% +it's we don't have to submit homework +both electronically and in paper no + + align:start position:0% +both electronically and in paper no + + + align:start position:0% +both electronically and in paper no +absolutely not if you do the electronic + + align:start position:0% +absolutely not if you do the electronic + + + align:start position:0% +absolutely not if you do the electronic +route which is the preferred we like + + align:start position:0% +route which is the preferred we like + + + align:start position:0% +route which is the preferred we like +electronic because it won't get + + align:start position:0% +electronic because it won't get + + + align:start position:0% +electronic because it won't get +lost the graders will absolutely have + + align:start position:0% +lost the graders will absolutely have + + + align:start position:0% +lost the graders will absolutely have +access to it because they're all in one + + align:start position:0% +access to it because they're all in one + + + align:start position:0% +access to it because they're all in one +place we like the electronic route but + + align:start position:0% +place we like the electronic route but + + + align:start position:0% +place we like the electronic route but +if you prefer paper just make sure you + + align:start position:0% +if you prefer paper just make sure you + + + align:start position:0% +if you prefer paper just make sure you +give us paper and one or the other + + align:start position:0% + + + + align:start position:0% + +suffices yes did we ever subm the + + align:start position:0% +suffices yes did we ever subm the + + + align:start position:0% +suffices yes did we ever subm the +questions on paper you you don't need + + align:start position:0% +questions on paper you you don't need + + + align:start position:0% +questions on paper you you don't need +to if you submit the tutor problems + + align:start position:0% +to if you submit the tutor problems + + + align:start position:0% +to if you submit the tutor problems +online and it says you're 100% correct + + align:start position:0% +online and it says you're 100% correct + + + align:start position:0% +online and it says you're 100% correct +you're done we don't ever need to see + + align:start position:0% +you're done we don't ever need to see + + + align:start position:0% +you're done we don't ever need to see +anything else you've got full + + align:start position:0% + + + + align:start position:0% + +credit other issues + + align:start position:0% + + + + align:start position:0% + +yes people are having technical problems + + align:start position:0% +yes people are having technical problems + + + align:start position:0% +yes people are having technical problems +with the tutor please tell us don't just + + align:start position:0% +with the tutor please tell us don't just + + + align:start position:0% +with the tutor please tell us don't just +feel like you have to kick out and do + + align:start position:0% +feel like you have to kick out and do + + + align:start position:0% +feel like you have to kick out and do +the paper version we're trying to we're + + align:start position:0% +the paper version we're trying to we're + + + align:start position:0% +the paper version we're trying to we're +trying to make sure that everything's in + + align:start position:0% +trying to make sure that everything's in + + + align:start position:0% +trying to make sure that everything's in +place this weekend we will try to be + + align:start position:0% +place this weekend we will try to be + + + align:start position:0% +place this weekend we will try to be +very responsive as I told you this is a + + align:start position:0% +very responsive as I told you this is a + + + align:start position:0% +very responsive as I told you this is a +brand new + + align:start position:0% +brand new + + + align:start position:0% +brand new +tutor we're very optimistic about it but + + align:start position:0% +tutor we're very optimistic about it but + + + align:start position:0% +tutor we're very optimistic about it but +we're also realistic software has bugs I + + align:start position:0% +we're also realistic software has bugs I + + + align:start position:0% +we're also realistic software has bugs I +don't tell any of my software people my + + align:start position:0% +don't tell any of my software people my + + + align:start position:0% +don't tell any of my software people my +software friends that uh3 no well well + + align:start position:0% +software friends that uh3 no well well + + + align:start position:0% +software friends that uh3 no well well +maybe I shouldn't say that software has + + align:start position:0% +maybe I shouldn't say that software has + + + align:start position:0% +maybe I shouldn't say that software has +bugs so we're trying to get rid of all + + align:start position:0% +bugs so we're trying to get rid of all + + + align:start position:0% +bugs so we're trying to get rid of all +of + + align:start position:0% + + + + align:start position:0% + +ours + + align:start position:0% +ours + + + align:start position:0% +ours +yeah I'm + + align:start position:0% +yeah I'm + + + align:start position:0% +yeah I'm +sorry and I'm still you have to shout + + align:start position:0% +sorry and I'm still you have to shout + + + align:start position:0% +sorry and I'm still you have to shout +because my hearing is done + + align:start position:0% +because my hearing is done + + + align:start position:0% +because my hearing is done +out if you run out of submits that's bad + + align:start position:0% +out if you run out of submits that's bad + + + align:start position:0% +out if you run out of submits that's bad +but during this sort of ramp up phase + + align:start position:0% +but during this sort of ramp up phase + + + align:start position:0% +but during this sort of ramp up phase +just send us an email because the goal + + align:start position:0% +just send us an email because the goal + + + align:start position:0% +just send us an email because the goal +is not to have you um run out of submits + + align:start position:0% +is not to have you um run out of submits + + + align:start position:0% +is not to have you um run out of submits +yet + + align:start position:0% +yet + + + align:start position:0% +yet +yes so if you run out if you run out of + + align:start position:0% +yes so if you run out if you run out of + + + align:start position:0% +yes so if you run out if you run out of +submit and your last submission was an + + align:start position:0% +submit and your last submission was an + + + align:start position:0% +submit and your last submission was an +incorrect answer but you turn something + + align:start position:0% +incorrect answer but you turn something + + + align:start position:0% +incorrect answer but you turn something +paper that + + align:start position:0% +paper that + + + align:start position:0% +paper that +answer if you continue to hit submit we + + align:start position:0% +answer if you continue to hit submit we + + + align:start position:0% +answer if you continue to hit submit we +will continue to be aware of it okay + + align:start position:0% +will continue to be aware of it okay + + + align:start position:0% +will continue to be aware of it okay +it's all in the great we know everything + + align:start position:0% +it's all in the great we know everything + + + align:start position:0% +it's all in the great we know everything +you've + + align:start position:0% +you've + + + align:start position:0% +you've +done so just go ahead and hit submit + + align:start position:0% +done so just go ahead and hit submit + + + align:start position:0% +done so just go ahead and hit submit +some more + + align:start position:0% +some more + + + align:start position:0% +some more +times but you can always turn in paper + + align:start position:0% +times but you can always turn in paper + + + align:start position:0% +times but you can always turn in paper +to overwrite it or you can always send + + align:start position:0% +to overwrite it or you can always send + + + align:start position:0% +to overwrite it or you can always send +me an email and say I ran R out of + + align:start position:0% +me an email and say I ran R out of + + + align:start position:0% +me an email and say I ran R out of +submits the answer is + + align:start position:0% +submits the answer is + + + align:start position:0% +submits the answer is +blah okay we're going to try to be very + + align:start position:0% +blah okay we're going to try to be very + + + align:start position:0% +blah okay we're going to try to be very +Cooperative this is + + align:start position:0% +Cooperative this is + + + align:start position:0% +Cooperative this is +new this is supposed to be + + align:start position:0% +new this is supposed to be + + + align:start position:0% +new this is supposed to be +helpful + + align:start position:0% + + + + align:start position:0% + +yes that's not supposed to be on your + + align:start position:0% +yes that's not supposed to be on your + + + align:start position:0% +yes that's not supposed to be on your +website that's supposed to be on my + + align:start position:0% +website that's supposed to be on my + + + align:start position:0% +website that's supposed to be on my +website I'll have to look into + + align:start position:0% + + + + align:start position:0% + +that if it works use it + + align:start position:0% + + + + align:start position:0% + +okay other other obvious errors that + + align:start position:0% +okay other other obvious errors that + + + align:start position:0% +okay other other obvious errors that +we've + + align:start position:0% +we've + + + align:start position:0% +we've +made okay let's go on and talk + + align:start position:0% +made okay let's go on and talk + + + align:start position:0% +made okay let's go on and talk +about3 what I want to do today well so + + align:start position:0% +about3 what I want to do today well so + + + align:start position:0% +about3 what I want to do today well so +last time last time I introduced what I + + align:start position:0% +last time last time I introduced what I + + + align:start position:0% +last time last time I introduced what I +call + + align:start position:0% +call + + + align:start position:0% +call +the 63 + + align:start position:0% + + + + align:start position:0% + +abstraction which is the idea that we + + align:start position:0% +abstraction which is the idea that we + + + align:start position:0% +abstraction which is the idea that we +represent a system Whatever It + + align:start position:0% +represent a system Whatever It + + + align:start position:0% +represent a system Whatever It +Is by the way it transforms an input + + align:start position:0% +Is by the way it transforms an input + + + align:start position:0% +Is by the way it transforms an input +signal + + align:start position:0% + + + + align:start position:0% + +to an output + + align:start position:0% + + + + align:start position:0% + +signal the goal for today is to start to + + align:start position:0% +signal the goal for today is to start to + + + align:start position:0% +signal the goal for today is to start to +develop Machinery that takes advantage + + align:start position:0% +develop Machinery that takes advantage + + + align:start position:0% +develop Machinery that takes advantage +of that + + align:start position:0% +of that + + + align:start position:0% +of that +representation we'll start by thinking + + align:start position:0% +representation we'll start by thinking + + + align:start position:0% +representation we'll start by thinking +about DT DT is conceptually easier than + + align:start position:0% +about DT DT is conceptually easier than + + + align:start position:0% +about DT DT is conceptually easier than +CT that's why we start there algebra is + + align:start position:0% +CT that's why we start there algebra is + + + align:start position:0% +CT that's why we start there algebra is +slightly easier than calculus that's the + + align:start position:0% + + + + align:start position:0% + +idea what we learn in DT will transfer + + align:start position:0% +idea what we learn in DT will transfer + + + align:start position:0% +idea what we learn in DT will transfer +almost verbatim into CT + + align:start position:0% +almost verbatim into CT + + + align:start position:0% +almost verbatim into CT +CTS like DT but a little harder so + + align:start position:0% +CTS like DT but a little harder so + + + align:start position:0% +CTS like DT but a little harder so +there's some extra stuff but the things + + align:start position:0% +there's some extra stuff but the things + + + align:start position:0% +there's some extra stuff but the things +we learned in DT will still be + + align:start position:0% +we learned in DT will still be + + + align:start position:0% +we learned in DT will still be +applicable in + + align:start position:0% +applicable in + + + align:start position:0% +applicable in +CT discrete time continuous + + align:start position:0% +CT discrete time continuous + + + align:start position:0% +CT discrete time continuous +time um furthermore DT is just + + align:start position:0% +time um furthermore DT is just + + + align:start position:0% +time um furthermore DT is just +important so increasingly applications + + align:start position:0% +important so increasingly applications + + + align:start position:0% +important so increasingly applications +in of this field are in discreete time + + align:start position:0% +in of this field are in discreete time + + + align:start position:0% +in of this field are in discreete time +that wasn't necessarily 220 years ago + + align:start position:0% +that wasn't necessarily 220 years ago + + + align:start position:0% +that wasn't necessarily 220 years ago +it's still the case that there's lots of + + align:start position:0% +it's still the case that there's lots of + + + align:start position:0% +it's still the case that there's lots of +applications that are intrinsically + + align:start position:0% +applications that are intrinsically + + + align:start position:0% +applications that are intrinsically +married to the physics that underly it + + align:start position:0% +married to the physics that underly it + + + align:start position:0% +married to the physics that underly it +that makes it intrinsically CT but a lot + + align:start position:0% +that makes it intrinsically CT but a lot + + + align:start position:0% +that makes it intrinsically CT but a lot +of stuff is done in DT so for a lot of + + align:start position:0% +of stuff is done in DT so for a lot of + + + align:start position:0% +of stuff is done in DT so for a lot of +reasons we're going to start with DT + + align:start position:0% +reasons we're going to start with DT + + + align:start position:0% +reasons we're going to start with DT +first and we're going to look today at + + align:start position:0% +first and we're going to look today at + + + align:start position:0% +first and we're going to look today at +several different representations of + + align:start position:0% +several different representations of + + + align:start position:0% +several different representations of +DT in particular we're going to look at + + align:start position:0% +DT in particular we're going to look at + + + align:start position:0% +DT in particular we're going to look at +difference equations and block + + align:start position:0% +difference equations and block + + + align:start position:0% +difference equations and block +diagrams and uh we're always interested + + align:start position:0% +diagrams and uh we're always interested + + + align:start position:0% +diagrams and uh we're always interested +in verbal descriptions because that's + + align:start position:0% +in verbal descriptions because that's + + + align:start position:0% +in verbal descriptions because that's +the way the real world is described to + + align:start position:0% +the way the real world is described to + + + align:start position:0% +the way the real world is described to +you so what we want to do is understand + + align:start position:0% +you so what we want to do is understand + + + align:start position:0% +you so what we want to do is understand +these understand their strengths and + + align:start position:0% +these understand their strengths and + + + align:start position:0% +these understand their strengths and +weaknesses so that we can capitalize on + + align:start position:0% +weaknesses so that we can capitalize on + + + align:start position:0% +weaknesses so that we can capitalize on +their strengths and go around their + + align:start position:0% +their strengths and go around their + + + align:start position:0% +their strengths and go around their +weaknesses that's the + + align:start position:0% +weaknesses that's the + + + align:start position:0% +weaknesses that's the +idea so the easiest possible + + align:start position:0% +idea so the easiest possible + + + align:start position:0% +idea so the easiest possible +representation is a difference equation + + align:start position:0% +representation is a difference equation + + + align:start position:0% +representation is a difference equation +difference equations are good because + + align:start position:0% +difference equations are good because + + + align:start position:0% +difference equations are good because +they're absolutely + + align:start position:0% +they're absolutely + + + align:start position:0% +they're absolutely +precise and they are the absolutely most + + align:start position:0% +precise and they are the absolutely most + + + align:start position:0% +precise and they are the absolutely most +concise representation we will + + align:start position:0% +concise representation we will + + + align:start position:0% +concise representation we will +have precise and concise those are good + + align:start position:0% +have precise and concise those are good + + + align:start position:0% +have precise and concise those are good +features so here's an example what if my + + align:start position:0% +features so here's an example what if my + + + align:start position:0% +features so here's an example what if my +output y + + align:start position:0% +output y + + + align:start position:0% +output y +where my input x - x n minus + + align:start position:0% +where my input x - x n minus + + + align:start position:0% +where my input x - x n minus +one let's say that the input is a unit + + align:start position:0% +one let's say that the input is a unit + + + align:start position:0% +one let's say that the input is a unit +sample we will often ask for the unit + + align:start position:0% +sample we will often ask for the unit + + + align:start position:0% +sample we will often ask for the unit +sample response the unit sample signal + + align:start position:0% +sample response the unit sample signal + + + align:start position:0% +sample response the unit sample signal +is the most simple nontrivial signal + + align:start position:0% +is the most simple nontrivial signal + + + align:start position:0% +is the most simple nontrivial signal +that we can have it is zero almost + + align:start position:0% +that we can have it is zero almost + + + align:start position:0% +that we can have it is zero almost +everywhere and the only place it's not + + align:start position:0% +everywhere and the only place it's not + + + align:start position:0% +everywhere and the only place it's not +zero is at zero and when it's not zero + + align:start position:0% +zero is at zero and when it's not zero + + + align:start position:0% +zero is at zero and when it's not zero +it's one so that's sort of the easiest + + align:start position:0% +it's one so that's sort of the easiest + + + align:start position:0% +it's one so that's sort of the easiest +thing we can imagine so what we're going + + align:start position:0% +thing we can imagine so what we're going + + + align:start position:0% +thing we can imagine so what we're going +to want to do then is think about what + + align:start position:0% +to want to do then is think about what + + + align:start position:0% +to want to do then is think about what +happens if we put this signal into that + + align:start position:0% +happens if we put this signal into that + + + align:start position:0% +happens if we put this signal into that +system okay that's completely trivial + + align:start position:0% +system okay that's completely trivial + + + align:start position:0% +system okay that's completely trivial +you've all done this a gazillion times + + align:start position:0% +you've all done this a gazillion times + + + align:start position:0% +you've all done this a gazillion times +before and now is your chance to prove + + align:start position:0% +before and now is your chance to prove + + + align:start position:0% +before and now is your chance to prove +it how many of those statements are true + + align:start position:0% +it how many of those statements are true + + + align:start position:0% +it how many of those statements are true +about the + + align:start position:0% +about the + + + align:start position:0% +about the +output of this system when that's the + + align:start position:0% +output of this system when that's the + + + align:start position:0% +output of this system when that's the +input talk to your neighbor you've got + + align:start position:0% +input talk to your neighbor you've got + + + align:start position:0% +input talk to your neighbor you've got +15 seconds this is too + + align:start position:0% +15 seconds this is too + + + align:start position:0% +15 seconds this is too +simple figure out how many of those + + align:start position:0% +simple figure out how many of those + + + align:start position:0% +simple figure out how many of those +statements are true + + align:start position:0% + + + + align:start position:0% + +you're allowed to + + align:start position:0% + + + + align:start position:0% + +talk for + + align:start position:0% + + + + align:start position:0% + +okay you're either all bored out of your + + align:start position:0% +okay you're either all bored out of your + + + align:start position:0% +okay you're either all bored out of your +minds or paralyzed with fear I can't + + align:start position:0% +minds or paralyzed with fear I can't + + + align:start position:0% +minds or paralyzed with fear I can't +tell so everybody raise your hand how + + align:start position:0% +tell so everybody raise your hand how + + + align:start position:0% +tell so everybody raise your hand how +many the statements are + + align:start position:0% +many the statements are + + + align:start position:0% +many the statements are +true more hands more hands come + + align:start position:0% + + + + align:start position:0% + +on okay less than half P half + + align:start position:0% +on okay less than half P half + + + align:start position:0% +on okay less than half P half +correct so um I'll just assume that you + + align:start position:0% +correct so um I'll just assume that you + + + align:start position:0% +correct so um I'll just assume that you +ran out of time and I'll go + + align:start position:0% +ran out of time and I'll go + + + align:start position:0% +ran out of time and I'll go +on so this is Trivial right what do I do + + align:start position:0% +on so this is Trivial right what do I do + + + align:start position:0% +on so this is Trivial right what do I do +how do I figure this out yeah step by + + align:start position:0% +how do I figure this out yeah step by + + + align:start position:0% +how do I figure this out yeah step by +step of course yes so if I think about + + align:start position:0% +step of course yes so if I think about + + + align:start position:0% +step of course yes so if I think about +applying this equation to that + + align:start position:0% +applying this equation to that + + + align:start position:0% +applying this equation to that +input then I can think about just + + align:start position:0% +input then I can think about just + + + align:start position:0% +input then I can think about just +substituting n = minus1 n = 0 n = 1 Nal + + align:start position:0% +substituting n = minus1 n = 0 n = 1 Nal + + + align:start position:0% +substituting n = minus1 n = 0 n = 1 Nal + + align:start position:0% + + + + align:start position:0% + +Etc and you can sort of see that I'm + + align:start position:0% +Etc and you can sort of see that I'm + + + align:start position:0% +Etc and you can sort of see that I'm +only looking at the input at two + + align:start position:0% +only looking at the input at two + + + align:start position:0% +only looking at the input at two +instance of time so there's a a finite + + align:start position:0% +instance of time so there's a a finite + + + align:start position:0% +instance of time so there's a a finite +range over which the input there's a + + align:start position:0% +range over which the input there's a + + + align:start position:0% +range over which the input there's a +finite range of inputs that can + + align:start position:0% +finite range of inputs that can + + + align:start position:0% +finite range of inputs that can +contribute to the output and in + + align:start position:0% +contribute to the output and in + + + align:start position:0% +contribute to the output and in +particular if I were to say if I were to + + align:start position:0% +particular if I were to say if I were to + + + align:start position:0% +particular if I were to say if I were to +substitute n equals minus1 I would see + + align:start position:0% +substitute n equals minus1 I would see + + + align:start position:0% +substitute n equals minus1 I would see +that the output at time y minus one + + align:start position:0% +that the output at time y minus one + + + align:start position:0% +that the output at time y minus one +depends on inputs before the Delta + + align:start position:0% +depends on inputs before the Delta + + + align:start position:0% +depends on inputs before the Delta +function + + align:start position:0% + + + + align:start position:0% + +started so therefore the answer is + + align:start position:0% +started so therefore the answer is + + + align:start position:0% +started so therefore the answer is +zero if I look at the output at time one + + align:start position:0% +zero if I look at the output at time one + + + align:start position:0% +zero if I look at the output at time one +the time one the time zero sorry the + + align:start position:0% +the time one the time zero sorry the + + + align:start position:0% +the time one the time zero sorry the +time zero input is one the time minus + + align:start position:0% +time zero input is one the time minus + + + align:start position:0% +time zero input is one the time minus +one input is zero so my total answer is + + align:start position:0% +one input is zero so my total answer is + + + align:start position:0% +one input is zero so my total answer is +one Etc right this is very + + align:start position:0% +one Etc right this is very + + + align:start position:0% +one Etc right this is very +straightforward it's just plug and + + align:start position:0% +straightforward it's just plug and + + + align:start position:0% +straightforward it's just plug and +chug and what you see is a + + align:start position:0% +chug and what you see is a + + + align:start position:0% +chug and what you see is a +waveform from which it's pretty easy to + + align:start position:0% +waveform from which it's pretty easy to + + + align:start position:0% +waveform from which it's pretty easy to +infer that Y2 was bigger than y1 right + + align:start position:0% +infer that Y2 was bigger than y1 right + + + align:start position:0% +infer that Y2 was bigger than y1 right +so Y2 was bigger than y1 bigger in a + + align:start position:0% +so Y2 was bigger than y1 bigger in a + + + align:start position:0% +so Y2 was bigger than y1 bigger in a +math + + align:start position:0% +math + + + align:start position:0% +math +sense and Y3 is bigger than y 2 not + + align:start position:0% +sense and Y3 is bigger than y 2 not + + + align:start position:0% +sense and Y3 is bigger than y 2 not +right Y3 and Y2 are + + align:start position:0% +right Y3 and Y2 are + + + align:start position:0% +right Y3 and Y2 are +identical so that's not + + align:start position:0% +identical so that's not + + + align:start position:0% +identical so that's not +true Y 2 and in fact everything above + + align:start position:0% +true Y 2 and in fact everything above + + + align:start position:0% +true Y 2 and in fact everything above +that is zero that's + + align:start position:0% +that is zero that's + + + align:start position:0% +that is zero that's +true and if you do a little bit of + + align:start position:0% +true and if you do a little bit of + + + align:start position:0% +true and if you do a little bit of +manipulation you can show that this must + + align:start position:0% +manipulation you can show that this must + + + align:start position:0% +manipulation you can show that this must +have also been TR everyone sort of see + + align:start position:0% + + + + align:start position:0% + +that I'm assuming you've seen all this + + align:start position:0% +that I'm assuming you've seen all this + + + align:start position:0% +that I'm assuming you've seen all this +sort of stuff before so I'm going to go + + align:start position:0% +sort of stuff before so I'm going to go + + + align:start position:0% +sort of stuff before so I'm going to go +through it kind of quickly but the + + align:start position:0% +through it kind of quickly but the + + + align:start position:0% +through it kind of quickly but the +answer was four four of those statement + + align:start position:0% +answer was four four of those statement + + + align:start position:0% +answer was four four of those statement +ments were true it was just a refresher + + align:start position:0% +ments were true it was just a refresher + + + align:start position:0% +ments were true it was just a refresher +on how to think about difference + + align:start position:0% +on how to think about difference + + + align:start position:0% +on how to think about difference +equations by comparison I want to + + align:start position:0% +equations by comparison I want to + + + align:start position:0% +equations by comparison I want to +contrast a difference equation on a + + align:start position:0% +contrast a difference equation on a + + + align:start position:0% +contrast a difference equation on a +block + + align:start position:0% + + + + align:start position:0% + +diagram this is the same system but + + align:start position:0% +diagram this is the same system but + + + align:start position:0% +diagram this is the same system but +represented + + align:start position:0% +represented + + + align:start position:0% +represented +graphically why would you want to do + + align:start position:0% +graphically why would you want to do + + + align:start position:0% +graphically why would you want to do +that okay well there's advantages and + + align:start position:0% +that okay well there's advantages and + + + align:start position:0% +that okay well there's advantages and +disadvantages this is a direct way of + + align:start position:0% +disadvantages this is a direct way of + + + align:start position:0% +disadvantages this is a direct way of +expressing the system if you wanted to + + align:start position:0% +expressing the system if you wanted to + + + align:start position:0% +expressing the system if you wanted to +implement it in Hardware so you can + + align:start position:0% +implement it in Hardware so you can + + + align:start position:0% +implement it in Hardware so you can +imagine building a delay box building an + + align:start position:0% +imagine building a delay box building an + + + align:start position:0% +imagine building a delay box building an +Adder building an + + align:start position:0% +Adder building an + + + align:start position:0% +Adder building an +inverter and constructing a piece of + + align:start position:0% +inverter and constructing a piece of + + + align:start position:0% +inverter and constructing a piece of +Hardware that does the computation so + + align:start position:0% +Hardware that does the computation so + + + align:start position:0% +Hardware that does the computation so +this is more like a hardware realization + + align:start position:0% +this is more like a hardware realization + + + align:start position:0% +this is more like a hardware realization +it's not as + + align:start position:0% +it's not as + + + align:start position:0% +it's not as +compact as the difference + + align:start position:0% +compact as the difference + + + align:start position:0% +compact as the difference +equation it has another idiosyncrasy + + align:start position:0% +equation it has another idiosyncrasy + + + align:start position:0% +equation it has another idiosyncrasy +that we have to have the notion of + + align:start position:0% +that we have to have the notion of + + + align:start position:0% +that we have to have the notion of +rest when we say the system starts at + + align:start position:0% +rest when we say the system starts at + + + align:start position:0% +rest when we say the system starts at +rest which we will say all the time and + + align:start position:0% +rest which we will say all the time and + + + align:start position:0% +rest which we will say all the time and +in fact you can always assume that + + align:start position:0% +in fact you can always assume that + + + align:start position:0% +in fact you can always assume that +unless we tell you something to the + + align:start position:0% +unless we tell you something to the + + + align:start position:0% +unless we tell you something to the +contrary when we say a system is at rest + + align:start position:0% +contrary when we say a system is at rest + + + align:start position:0% +contrary when we say a system is at rest +what we mean is that all the delays in + + align:start position:0% +what we mean is that all the delays in + + + align:start position:0% +what we mean is that all the delays in +the system start out being + + align:start position:0% +the system start out being + + + align:start position:0% +the system start out being +zero so at rest means that this signal + + align:start position:0% +zero so at rest means that this signal + + + align:start position:0% +zero so at rest means that this signal +starts out at zero because that's the + + align:start position:0% +starts out at zero because that's the + + + align:start position:0% +starts out at zero because that's the +only there's only one delay in the + + align:start position:0% +only there's only one delay in the + + + align:start position:0% +only there's only one delay in the +system its output is initially zero so + + align:start position:0% +system its output is initially zero so + + + align:start position:0% +system its output is initially zero so +now we think about the input chugging + + align:start position:0% +now we think about the input chugging + + + align:start position:0% +now we think about the input chugging +along so the input starts out being one + + align:start position:0% +along so the input starts out being one + + + align:start position:0% +along so the input starts out being one +that means the inverted input is minus + + align:start position:0% +that means the inverted input is minus + + + align:start position:0% +that means the inverted input is minus +one that doesn't profit propagate + + align:start position:0% +one that doesn't profit propagate + + + align:start position:0% +one that doesn't profit propagate +through the delay because we're still at + + align:start position:0% +through the delay because we're still at + + + align:start position:0% +through the delay because we're still at +the instant when the input just became + + align:start position:0% +the instant when the input just became + + + align:start position:0% +the instant when the input just became +one for the first + + align:start position:0% +one for the first + + + align:start position:0% +one for the first +time so this one goes through and adds + + align:start position:0% +time so this one goes through and adds + + + align:start position:0% +time so this one goes through and adds +to this zero to give us one and our + + align:start position:0% +to this zero to give us one and our + + + align:start position:0% +to this zero to give us one and our +answer is + + align:start position:0% +answer is + + + align:start position:0% +answer is +one now the clock goes + + align:start position:0% +one now the clock goes + + + align:start position:0% +one now the clock goes +kachunk and at that instant the input + + align:start position:0% +kachunk and at that instant the input + + + align:start position:0% +kachunk and at that instant the input +changes from one to zero because that's + + align:start position:0% +changes from one to zero because that's + + + align:start position:0% +changes from one to zero because that's +what happens + + align:start position:0% +what happens + + + align:start position:0% +what happens +here and at precisely the same instant + + align:start position:0% +here and at precisely the same instant + + + align:start position:0% +here and at precisely the same instant +the delay signal went from zero which it + + align:start position:0% +the delay signal went from zero which it + + + align:start position:0% +the delay signal went from zero which it +was because it started at rest to minus + + align:start position:0% +was because it started at rest to minus + + + align:start position:0% +was because it started at rest to minus +one which was its input just before + + align:start position:0% + + + + align:start position:0% + +kachunk + + align:start position:0% +kachunk + + + align:start position:0% +kachunk +then after the signal settle down this + + align:start position:0% +then after the signal settle down this + + + align:start position:0% +then after the signal settle down this +becomes zero and this becomes minus one + + align:start position:0% +becomes zero and this becomes minus one + + + align:start position:0% +becomes zero and this becomes minus one +and that's our + + align:start position:0% +and that's our + + + align:start position:0% +and that's our +output then U again + + align:start position:0% +output then U again + + + align:start position:0% +output then U again +kachunk the input doesn't change because + + align:start position:0% +kachunk the input doesn't change because + + + align:start position:0% +kachunk the input doesn't change because +it was Zero it's still zero but the + + align:start position:0% +it was Zero it's still zero but the + + + align:start position:0% +it was Zero it's still zero but the +delay now goes from minus one the output + + align:start position:0% +delay now goes from minus one the output + + + align:start position:0% +delay now goes from minus one the output +of the delay goes from minus one to + + align:start position:0% +of the delay goes from minus one to + + + align:start position:0% +of the delay goes from minus one to +zero and after things settle down we get + + align:start position:0% +zero and after things settle down we get + + + align:start position:0% +zero and after things settle down we get +uh zero at the + + align:start position:0% +uh zero at the + + + align:start position:0% +uh zero at the +output and that is a state that + + align:start position:0% +output and that is a state that + + + align:start position:0% +output and that is a state that +persists okay so we have these two + + align:start position:0% +persists okay so we have these two + + + align:start position:0% +persists okay so we have these two +different representations we have + + align:start position:0% +different representations we have + + + align:start position:0% +different representations we have +different equations of block diagrams so + + align:start position:0% +different equations of block diagrams so + + + align:start position:0% +different equations of block diagrams so +here's a question how are they + + align:start position:0% + + + + align:start position:0% + +different in particular I've told you + + align:start position:0% +different in particular I've told you + + + align:start position:0% +different in particular I've told you +that difference equations are concise + + align:start position:0% +that difference equations are concise + + + align:start position:0% +that difference equations are concise +and precise + + align:start position:0% + + + + align:start position:0% + +are there advantages to a block + + align:start position:0% +are there advantages to a block + + + align:start position:0% +are there advantages to a block +diagram talk to your neighbor come up + + align:start position:0% +diagram talk to your neighbor come up + + + align:start position:0% +diagram talk to your neighbor come up +with a good + + align:start position:0% + + + + align:start position:0% + +hypothesis what's good about a block + + align:start position:0% +hypothesis what's good about a block + + + align:start position:0% +hypothesis what's good about a block +diagram anything + + align:start position:0% + + + + align:start position:0% + +so can anybody think of something good + + align:start position:0% +so can anybody think of something good + + + align:start position:0% +so can anybody think of something good +about a block + + align:start position:0% + + + + align:start position:0% + +diagram yeah you change a system you can + + align:start position:0% +diagram yeah you change a system you can + + + align:start position:0% +diagram yeah you change a system you can +systems andas to + + align:start position:0% +systems andas to + + + align:start position:0% +systems andas to +so it's easy to see so that could be + + align:start position:0% +so it's easy to see so that could be + + + align:start position:0% +so it's easy to see so that could be +something to do with a graphic + + align:start position:0% +something to do with a graphic + + + align:start position:0% +something to do with a graphic +representation it but it could be deeper + + align:start position:0% +representation it but it could be deeper + + + align:start position:0% +representation it but it could be deeper +too can somebody say a deeper reason why + + align:start position:0% +too can somebody say a deeper reason why + + + align:start position:0% +too can somebody say a deeper reason why +it might be easier to see so that might + + align:start position:0% +it might be easier to see so that might + + + align:start position:0% +it might be easier to see so that might +be a very good that might be a deep + + align:start position:0% +be a very good that might be a deep + + + align:start position:0% +be a very good that might be a deep +comment too why might it be easier to + + align:start position:0% +comment too why might it be easier to + + + align:start position:0% +comment too why might it be easier to +use the block diagram than it is to use + + align:start position:0% +use the block diagram than it is to use + + + align:start position:0% +use the block diagram than it is to use +the difference + + align:start position:0% + + + + align:start position:0% + +equation + + align:start position:0% +equation + + + align:start position:0% +equation +yeah steps how so so there's um like + + align:start position:0% +yeah steps how so so there's um like + + + align:start position:0% +yeah steps how so so there's um like +there's a delay and then there's the + + align:start position:0% +there's a delay and then there's the + + + align:start position:0% +there's a delay and then there's the +feed so it's like + + align:start position:0% + + + + align:start position:0% + +allence so that's kind of right I'm + + align:start position:0% +allence so that's kind of right I'm + + + align:start position:0% +allence so that's kind of right I'm +wondering if you can say so this is kind + + align:start position:0% +wondering if you can say so this is kind + + + align:start position:0% +wondering if you can say so this is kind +of I mean you just do this right you do + + align:start position:0% +of I mean you just do this right you do + + + align:start position:0% +of I mean you just do this right you do +this and then you do that what's the + + align:start position:0% + + + + align:start position:0% + +difference there's something very + + align:start position:0% +difference there's something very + + + align:start position:0% +difference there's something very +different about those two + + align:start position:0% +different about those two + + + align:start position:0% +different about those two +representations there is more + + align:start position:0% +representations there is more + + + align:start position:0% +representations there is more +information in the bottom than there is + + align:start position:0% +information in the bottom than there is + + + align:start position:0% +information in the bottom than there is +in the + + align:start position:0% +in the + + + align:start position:0% +in the +top can somebody tell me the information + + align:start position:0% +top can somebody tell me the information + + + align:start position:0% +top can somebody tell me the information +that's available in the bottom that's + + align:start position:0% +that's available in the bottom that's + + + align:start position:0% +that's available in the bottom that's +not available in the top yes it do when + + align:start position:0% +not available in the top yes it do when + + + align:start position:0% +not available in the top yes it do when +you're actually assembling circuits it + + align:start position:0% +you're actually assembling circuits it + + + align:start position:0% +you're actually assembling circuits it +becomes a lot easier to use just the + + align:start position:0% +becomes a lot easier to use just the + + + align:start position:0% +becomes a lot easier to use just the +graphical representation you know + + align:start position:0% +graphical representation you know + + + align:start position:0% +graphical representation you know +circuit graphical but can but is there + + align:start position:0% +circuit graphical but can but is there + + + align:start position:0% +circuit graphical but can but is there +additional information here that wasn't + + align:start position:0% +additional information here that wasn't + + + align:start position:0% +additional information here that wasn't +available + + align:start position:0% +available + + + align:start position:0% +available +there + + align:start position:0% +there + + + align:start position:0% +there +yes number of signal path signal paths + + align:start position:0% +yes number of signal path signal paths + + + align:start position:0% +yes number of signal path signal paths +is a good idea + + align:start position:0% + + + + align:start position:0% + +yes well that sort of goes with + + align:start position:0% +yes well that sort of goes with + + + align:start position:0% +yes well that sort of goes with +specifying a + + align:start position:0% + + + + align:start position:0% + +yes it is easier but there's a very + + align:start position:0% +yes it is easier but there's a very + + + align:start position:0% +yes it is easier but there's a very +precise reason why it's easier there's + + align:start position:0% + + + + align:start position:0% + +arrows the arrows tell you what to do + + align:start position:0% +arrows the arrows tell you what to do + + + align:start position:0% +arrows the arrows tell you what to do +next right so the thing that's different + + align:start position:0% +next right so the thing that's different + + + align:start position:0% +next right so the thing that's different +is that from the structure of the arrows + + align:start position:0% +is that from the structure of the arrows + + + align:start position:0% +is that from the structure of the arrows +everything starts here + + align:start position:0% +everything starts here + + + align:start position:0% +everything starts here +and you should worry about what goes + + align:start position:0% +and you should worry about what goes + + + align:start position:0% +and you should worry about what goes +that way and what goes that way and what + + align:start position:0% +that way and what goes that way and what + + + align:start position:0% +that way and what goes that way and what +goes that way and how that comes + + align:start position:0% +goes that way and how that comes + + + align:start position:0% +goes that way and how that comes +together there there's more + + align:start position:0% +together there there's more + + + align:start position:0% +together there there's more +information in kind of computer science + + align:start position:0% +information in kind of computer science + + + align:start position:0% +information in kind of computer science +terms we would say that the difference + + align:start position:0% +terms we would say that the difference + + + align:start position:0% +terms we would say that the difference +equation is + + align:start position:0% +equation is + + + align:start position:0% +equation is +declarative it tells you a statement of + + align:start position:0% +declarative it tells you a statement of + + + align:start position:0% +declarative it tells you a statement of +fact not necessarily what you can do + + align:start position:0% +fact not necessarily what you can do + + + align:start position:0% +fact not necessarily what you can do +with + + align:start position:0% +with + + + align:start position:0% +with +it the block diagram is + + align:start position:0% +it the block diagram is + + + align:start position:0% +it the block diagram is +imperative it tells you how to do + + align:start position:0% +imperative it tells you how to do + + + align:start position:0% +imperative it tells you how to do +something + + align:start position:0% +something + + + align:start position:0% +something +and those are very different so the + + align:start position:0% +and those are very different so the + + + align:start position:0% +and those are very different so the +difference equation is concise precise + + align:start position:0% +difference equation is concise precise + + + align:start position:0% +difference equation is concise precise +and declarative the block diagram is + + align:start position:0% +and declarative the block diagram is + + + align:start position:0% +and declarative the block diagram is +imperative do this do this do this it + + align:start position:0% +imperative do this do this do this it + + + align:start position:0% +imperative do this do this do this it +shows you the signal flow path there's + + align:start position:0% +shows you the signal flow path there's + + + align:start position:0% +shows you the signal flow path there's +no question about who causes what right + + align:start position:0% +no question about who causes what right + + + align:start position:0% +no question about who causes what right +in this we could be Computing X from y + + align:start position:0% +in this we could be Computing X from y + + + align:start position:0% +in this we could be Computing X from y +or Y from X there's no indication other + + align:start position:0% +or Y from X there's no indication other + + + align:start position:0% +or Y from X there's no indication other +than some convention someplace that the + + align:start position:0% +than some convention someplace that the + + + align:start position:0% +than some convention someplace that the +x is the imput but do that make + + align:start position:0% +x is the imput but do that make + + + align:start position:0% +x is the imput but do that make +sense okay so uh there's a very big + + align:start position:0% +sense okay so uh there's a very big + + + align:start position:0% +sense okay so uh there's a very big +difference there's another step we want + + align:start position:0% +difference there's another step we want + + + align:start position:0% +difference there's another step we want +to take so imperative and declarative + + align:start position:0% +to take so imperative and declarative + + + align:start position:0% +to take so imperative and declarative +what is one step another step is lumping + + align:start position:0% +what is one step another step is lumping + + + align:start position:0% +what is one step another step is lumping +things in the same sense that we lump + + align:start position:0% +things in the same sense that we lump + + + align:start position:0% +things in the same sense that we lump +the coordinates of a three- space Point + + align:start position:0% +the coordinates of a three- space Point + + + align:start position:0% +the coordinates of a three- space Point +into a single thing called a point or in + + align:start position:0% +into a single thing called a point or in + + + align:start position:0% +into a single thing called a point or in +the same way we make a vector in linear + + align:start position:0% +the same way we make a vector in linear + + + align:start position:0% +the same way we make a vector in linear +algebra the idea is going to be that + + align:start position:0% +algebra the idea is going to be that + + + align:start position:0% +algebra the idea is going to be that +we're going to want to think about whole + + align:start position:0% +we're going to want to think about whole + + + align:start position:0% +we're going to want to think about whole +signals at a time + + align:start position:0% + + + + align:start position:0% + +so by and the notation that we will use + + align:start position:0% +so by and the notation that we will use + + + align:start position:0% +so by and the notation that we will use +we will think about uh how this will be + + align:start position:0% +we will think about uh how this will be + + + align:start position:0% +we will think about uh how this will be +the X + + align:start position:0% +the X + + + align:start position:0% +the X +signal this will be the Y signal and we + + align:start position:0% +signal this will be the Y signal and we + + + align:start position:0% +signal this will be the Y signal and we +can reinterpret the block diagram to be + + align:start position:0% +can reinterpret the block diagram to be + + + align:start position:0% +can reinterpret the block diagram to be +operations on + + align:start position:0% +operations on + + + align:start position:0% +operations on +signals rather than operations on + + align:start position:0% +signals rather than operations on + + + align:start position:0% +signals rather than operations on +samples okay so I'm trying to to develop + + align:start position:0% +samples okay so I'm trying to to develop + + + align:start position:0% +samples okay so I'm trying to to develop +a level of abstraction that help helps + + align:start position:0% +a level of abstraction that help helps + + + align:start position:0% +a level of abstraction that help helps +us predict the way systems will behave + + align:start position:0% +us predict the way systems will behave + + + align:start position:0% +us predict the way systems will behave +so the next level of abstraction I want + + align:start position:0% +so the next level of abstraction I want + + + align:start position:0% +so the next level of abstraction I want +to think about is thinking about whole + + align:start position:0% +to think about is thinking about whole + + + align:start position:0% +to think about is thinking about whole +signals at + + align:start position:0% +signals at + + + align:start position:0% +signals at +once so if we take this signal idea we + + align:start position:0% +once so if we take this signal idea we + + + align:start position:0% +once so if we take this signal idea we +would say there's an X signal it gets + + align:start position:0% +would say there's an X signal it gets + + + align:start position:0% +would say there's an X signal it gets +operated by this inverter to give an + + align:start position:0% +operated by this inverter to give an + + + align:start position:0% +operated by this inverter to give an +inverted + + align:start position:0% +inverted + + + align:start position:0% +inverted +signal the this signal goes through a + + align:start position:0% +signal the this signal goes through a + + + align:start position:0% +signal the this signal goes through a +delay box to give us a delayed inverted + + align:start position:0% +delay box to give us a delayed inverted + + + align:start position:0% +delay box to give us a delayed inverted +signal the delayed inverted signal gets + + align:start position:0% +signal the delayed inverted signal gets + + + align:start position:0% +signal the delayed inverted signal gets +added to the original signal and that + + align:start position:0% +added to the original signal and that + + + align:start position:0% +added to the original signal and that +gives us an output signal so we think + + align:start position:0% +gives us an output signal so we think + + + align:start position:0% +gives us an output signal so we think +about the nodes being whole + + align:start position:0% +about the nodes being whole + + + align:start position:0% +about the nodes being whole +signals and the boxes being operators on + + align:start position:0% +signals and the boxes being operators on + + + align:start position:0% +signals and the boxes being operators on +signals not samples that's a huge + + align:start position:0% +signals not samples that's a huge + + + align:start position:0% +signals not samples that's a huge +difference and to make sure to be + + align:start position:0% +difference and to make sure to be + + + align:start position:0% +difference and to make sure to be +explicit about that we'll develop a + + align:start position:0% +explicit about that we'll develop a + + + align:start position:0% +explicit about that we'll develop a +notation we will say there's an operator + + align:start position:0% +notation we will say there's an operator + + + align:start position:0% +notation we will say there's an operator +r the right shift + + align:start position:0% +r the right shift + + + align:start position:0% +r the right shift +operator that operates on + + align:start position:0% +operator that operates on + + + align:start position:0% +operator that operates on +signals so we'll think about if x is the + + align:start position:0% +signals so we'll think about if x is the + + + align:start position:0% +signals so we'll think about if x is the +whole input signal not the N sample the + + align:start position:0% +whole input signal not the N sample the + + + align:start position:0% +whole input signal not the N sample the +whole thing + + align:start position:0% +whole thing + + + align:start position:0% +whole thing +if x is a signal we can operate it on it + + align:start position:0% +if x is a signal we can operate it on it + + + align:start position:0% +if x is a signal we can operate it on it +by the r operator we can apply r the + + align:start position:0% +by the r operator we can apply r the + + + align:start position:0% +by the r operator we can apply r the +right shift operator to the signal X and + + align:start position:0% +right shift operator to the signal X and + + + align:start position:0% +right shift operator to the signal X and +generate a whole new signal which I'll + + align:start position:0% +generate a whole new signal which I'll + + + align:start position:0% +generate a whole new signal which I'll +call + + align:start position:0% +call + + + align:start position:0% +call +Y which will be a shifted version of the + + align:start position:0% +Y which will be a shifted version of the + + + align:start position:0% +Y which will be a shifted version of the +X signal okay you all got + + align:start position:0% +X signal okay you all got + + + align:start position:0% +X signal okay you all got +that and that leads us then to a concise + + align:start position:0% +that and that leads us then to a concise + + + align:start position:0% +that and that leads us then to a concise +representation similar to the difference + + align:start position:0% +representation similar to the difference + + + align:start position:0% +representation similar to the difference +equation but that has the features of + + align:start position:0% +equation but that has the features of + + + align:start position:0% +equation but that has the features of +the block diagram because it's + + align:start position:0% +the block diagram because it's + + + align:start position:0% +the block diagram because it's +imperative R operating on X tells me + + align:start position:0% +imperative R operating on X tells me + + + align:start position:0% +imperative R operating on X tells me +start with X and apply R to it there's a + + align:start position:0% +start with X and apply R to it there's a + + + align:start position:0% +start with X and apply R to it there's a +direction R applied to X is imperative + + align:start position:0% +direction R applied to X is imperative + + + align:start position:0% +direction R applied to X is imperative +it tells me what to do so this is a way + + align:start position:0% +it tells me what to do so this is a way + + + align:start position:0% +it tells me what to do so this is a way +that I can uh make a notation that is as + + align:start position:0% +that I can uh make a notation that is as + + + align:start position:0% +that I can uh make a notation that is as +concise as difference equations but has + + align:start position:0% +concise as difference equations but has + + + align:start position:0% +concise as difference equations but has +the same imperative feature as a block + + align:start position:0% +the same imperative feature as a block + + + align:start position:0% +the same imperative feature as a block +diagram so it's an improved not in that + + align:start position:0% +diagram so it's an improved not in that + + + align:start position:0% +diagram so it's an improved not in that +sense okay make sure that you know what + + align:start position:0% +sense okay make sure that you know what + + + align:start position:0% +sense okay make sure that you know what +it means if I said that Y is rx how many + + align:start position:0% +it means if I said that Y is rx how many + + + align:start position:0% +it means if I said that Y is rx how many +of the following is + + align:start position:0% + + + + align:start position:0% + +true now you have to redeem yourself + + align:start position:0% +true now you have to redeem yourself + + + align:start position:0% +true now you have to redeem yourself +right you less than 50% right so now I + + align:start position:0% +right you less than 50% right so now I + + + align:start position:0% +right you less than 50% right so now I +want 90% + + align:start position:0% + + + + align:start position:0% + +right oh excuse me not how many which + + align:start position:0% + + + + align:start position:0% + +okay everybody raise your hands come + + align:start position:0% +okay everybody raise your hands come + + + align:start position:0% +okay everybody raise your hands come +on this is redemption time ah wonderful + + align:start position:0% +on this is redemption time ah wonderful + + + align:start position:0% +on this is redemption time ah wonderful +you're redeemed so you're about 100% + + align:start position:0% +you're redeemed so you're about 100% + + + align:start position:0% +you're redeemed so you're about 100% +correct um so it to think about that one + + align:start position:0% +correct um so it to think about that one + + + align:start position:0% +correct um so it to think about that one +easy way to think about it is by example + + align:start position:0% +easy way to think about it is by example + + + align:start position:0% +easy way to think about it is by example +examples can't prove that something's + + align:start position:0% +examples can't prove that something's + + + align:start position:0% +examples can't prove that something's +true but they can quickly prove that + + align:start position:0% +true but they can quickly prove that + + + align:start position:0% +true but they can quickly prove that +something's + + align:start position:0% +something's + + + align:start position:0% +something's +false so if you think about the simplest + + align:start position:0% +false so if you think about the simplest + + + align:start position:0% +false so if you think about the simplest +possible signal say you had a unit + + align:start position:0% +possible signal say you had a unit + + + align:start position:0% +possible signal say you had a unit +sample if you applied R to that it would + + align:start position:0% +sample if you applied R to that it would + + + align:start position:0% +sample if you applied R to that it would +shift it to the + + align:start position:0% +shift it to the + + + align:start position:0% +shift it to the +right if it shifts it to the right it's + + align:start position:0% +right if it shifts it to the right it's + + + align:start position:0% +right if it shifts it to the right it's +pretty clear that Y at time one is the + + align:start position:0% +pretty clear that Y at time one is the + + + align:start position:0% +pretty clear that Y at time one is the +same as X at time + + align:start position:0% + + + + align:start position:0% + +zero and that's a feature + + align:start position:0% +zero and that's a feature + + + align:start position:0% +zero and that's a feature +of this equation and none of the + + align:start position:0% +of this equation and none of the + + + align:start position:0% +of this equation and none of the +others so that proves the others are + + align:start position:0% +others so that proves the others are + + + align:start position:0% +others so that proves the others are +wrong and if you think about a little + + align:start position:0% +wrong and if you think about a little + + + align:start position:0% +wrong and if you think about a little +bit you can generalize that argument to + + align:start position:0% +bit you can generalize that argument to + + + align:start position:0% +bit you can generalize that argument to +prove that the the second one is + + align:start position:0% +prove that the the second one is + + + align:start position:0% +prove that the the second one is +actually true uh for all the cases + + align:start position:0% +actually true uh for all the cases + + + align:start position:0% +actually true uh for all the cases +okay so the idea then is that we want to + + align:start position:0% +okay so the idea then is that we want to + + + align:start position:0% +okay so the idea then is that we want to +think about this hybrid notation this + + align:start position:0% +think about this hybrid notation this + + + align:start position:0% +think about this hybrid notation this +operator + + align:start position:0% +operator + + + align:start position:0% +operator +notation and we want to think about how + + align:start position:0% +notation and we want to think about how + + + align:start position:0% +notation and we want to think about how +to represent simple systems that way so + + align:start position:0% +to represent simple systems that way so + + + align:start position:0% +to represent simple systems that way so +here's an example say I have this system + + align:start position:0% +here's an example say I have this system + + + align:start position:0% +here's an example say I have this system +I can think about that as the Cascade of + + align:start position:0% +I can think about that as the Cascade of + + + align:start position:0% +I can think about that as the Cascade of +a system that starts with + + align:start position:0% +a system that starts with + + + align:start position:0% +a system that starts with +X X is a signal and this whole thing + + align:start position:0% +X X is a signal and this whole thing + + + align:start position:0% +X X is a signal and this whole thing +gets turned into an + + align:start position:0% +gets turned into an + + + align:start position:0% +gets turned into an +operator that operator is can be written + + align:start position:0% +operator that operator is can be written + + + align:start position:0% +operator that operator is can be written +mathematically as one this path added to + + align:start position:0% +mathematically as one this path added to + + + align:start position:0% +mathematically as one this path added to +minus1 times a delay minus one time a + + align:start position:0% +minus1 times a delay minus one time a + + + align:start position:0% +minus1 times a delay minus one time a +delay so one - R operating on X gives me + + align:start position:0% +delay so one - R operating on X gives me + + + align:start position:0% +delay so one - R operating on X gives me +y1 then a similar system operates on y1 + + align:start position:0% +y1 then a similar system operates on y1 + + + align:start position:0% +y1 then a similar system operates on y1 +to give me + + align:start position:0% +to give me + + + align:start position:0% +to give me +Y2 and if the rules of math apply I + + align:start position:0% +Y2 and if the rules of math apply I + + + align:start position:0% +Y2 and if the rules of math apply I +ought to be able to + + align:start position:0% +ought to be able to + + + align:start position:0% +ought to be able to +substitute 1 - RX for + + align:start position:0% +substitute 1 - RX for + + + align:start position:0% +substitute 1 - RX for +y1 and get that expression + + align:start position:0% +y1 and get that expression + + + align:start position:0% +y1 and get that expression +right and if the world were nice and it + + align:start position:0% +right and if the world were nice and it + + + align:start position:0% +right and if the world were nice and it +is if the world were nice then this + + align:start position:0% +is if the world were nice then this + + + align:start position:0% +is if the world were nice then this +expression since it looks like a polom + + align:start position:0% +expression since it looks like a polom + + + align:start position:0% +expression since it looks like a polom +in r + + align:start position:0% +in r + + + align:start position:0% +in r +behave like a polom in + + align:start position:0% +behave like a polom in + + + align:start position:0% +behave like a polom in +R and it's pretty easy to convince + + align:start position:0% +R and it's pretty easy to convince + + + align:start position:0% +R and it's pretty easy to convince +yourself that that's in fact + + align:start position:0% +yourself that that's in fact + + + align:start position:0% +yourself that that's in fact +true so think about the Primitive + + align:start position:0% +true so think about the Primitive + + + align:start position:0% +true so think about the Primitive +definition sample by sample difference + + align:start position:0% +definition sample by sample difference + + + align:start position:0% +definition sample by sample difference +equation what should this + + align:start position:0% +equation what should this + + + align:start position:0% +equation what should this +do well there's a difference + + align:start position:0% +do well there's a difference + + + align:start position:0% +do well there's a difference +representation for this which is here + + align:start position:0% +representation for this which is here + + + align:start position:0% +representation for this which is here +there's a difference representation for + + align:start position:0% +there's a difference representation for + + + align:start position:0% +there's a difference representation for +this which I can substitute + + align:start position:0% +this which I can substitute + + + align:start position:0% +this which I can substitute +twice so I can generate an equivalent + + align:start position:0% +twice so I can generate an equivalent + + + align:start position:0% +twice so I can generate an equivalent +difference equation for the whole + + align:start position:0% + + + + align:start position:0% + +thing and then I can think about + + align:start position:0% +thing and then I can think about + + + align:start position:0% +thing and then I can think about +termwise translating all those into R + + align:start position:0% +termwise translating all those into R + + + align:start position:0% +termwise translating all those into R +expressions and I see that I have proved + + align:start position:0% +expressions and I see that I have proved + + + align:start position:0% +expressions and I see that I have proved +the idea that this particular system at + + align:start position:0% +the idea that this particular system at + + + align:start position:0% +the idea that this particular system at +least behaves as though the operator + + align:start position:0% +least behaves as though the operator + + + align:start position:0% +least behaves as though the operator +Expressions follow the rules of + + align:start position:0% +Expressions follow the rules of + + + align:start position:0% +Expressions follow the rules of +pols it's important so that important + + align:start position:0% +pols it's important so that important + + + align:start position:0% +pols it's important so that important +right because you know how to deal with + + align:start position:0% +right because you know how to deal with + + + align:start position:0% +right because you know how to deal with +pols if there's an isomorphism between + + align:start position:0% +pols if there's an isomorphism between + + + align:start position:0% +pols if there's an isomorphism between +these kinds of discrete time signals and + + align:start position:0% +these kinds of discrete time signals and + + + align:start position:0% +these kinds of discrete time signals and +pols the fact that you know how to deal + + align:start position:0% +pols the fact that you know how to deal + + + align:start position:0% +pols the fact that you know how to deal +with polinomial translates in to you + + align:start position:0% +with polinomial translates in to you + + + align:start position:0% +with polinomial translates in to you +already know how to do systems right so + + align:start position:0% +already know how to do systems right so + + + align:start position:0% +already know how to do systems right so +it's a very powerful kind of thing to + + align:start position:0% +it's a very powerful kind of thing to + + + align:start position:0% +it's a very powerful kind of thing to +draw an isomorphism between two systems + + align:start position:0% +draw an isomorphism between two systems + + + align:start position:0% +draw an isomorphism between two systems +especially when you already know how to + + align:start position:0% +especially when you already know how to + + + align:start position:0% +especially when you already know how to +do one of + + align:start position:0% + + + + align:start position:0% + +them so let's think about equivalence a + + align:start position:0% +them so let's think about equivalence a + + + align:start position:0% +them so let's think about equivalence a +little more here's a another example so + + align:start position:0% +little more here's a another example so + + + align:start position:0% +little more here's a another example so +here's that same + + align:start position:0% +here's that same + + + align:start position:0% +here's that same +system that's composed of two cascaded + + align:start position:0% +system that's composed of two cascaded + + + align:start position:0% +system that's composed of two cascaded +difference + + align:start position:0% +difference + + + align:start position:0% +difference +engines and the hypothesis is that this + + align:start position:0% +engines and the hypothesis is that this + + + align:start position:0% +engines and the hypothesis is that this +is the + + align:start position:0% + + + + align:start position:0% + +same two things I want you to see first + + align:start position:0% +same two things I want you to see first + + + align:start position:0% +same two things I want you to see first +it should be pretty clear that you can + + align:start position:0% +it should be pretty clear that you can + + + align:start position:0% +it should be pretty clear that you can +see how you would derive that thinking + + align:start position:0% +see how you would derive that thinking + + + align:start position:0% +see how you would derive that thinking +about the system as operators + + align:start position:0% +about the system as operators + + + align:start position:0% +about the system as operators +are you should also be able to derive + + align:start position:0% +are you should also be able to derive + + + align:start position:0% +are you should also be able to derive +the equivalence by thinking about the + + align:start position:0% +the equivalence by thinking about the + + + align:start position:0% +the equivalence by thinking about the +individual blocks as difference + + align:start position:0% +individual blocks as difference + + + align:start position:0% +individual blocks as difference +equations but more importantly I'm + + align:start position:0% +equations but more importantly I'm + + + align:start position:0% +equations but more importantly I'm +hoping that you can see a + + align:start position:0% +hoping that you can see a + + + align:start position:0% +hoping that you can see a +caveat assuming both are initially at + + align:start position:0% +caveat assuming both are initially at + + + align:start position:0% +caveat assuming both are initially at +rest that will come up over and over and + + align:start position:0% +rest that will come up over and over and + + + align:start position:0% +rest that will come up over and over and +over and over again for exactly this + + align:start position:0% +over and over again for exactly this + + + align:start position:0% +over and over again for exactly this +reason the equivalence is only true if + + align:start position:0% +reason the equivalence is only true if + + + align:start position:0% +reason the equivalence is only true if +they started + + align:start position:0% +they started + + + align:start position:0% +they started +rest that's not quite the right way to + + align:start position:0% +rest that's not quite the right way to + + + align:start position:0% +rest that's not quite the right way to +say it the equivalence is always true if + + align:start position:0% +say it the equivalence is always true if + + + align:start position:0% +say it the equivalence is always true if +they start at rest that is precisely + + align:start position:0% +they start at rest that is precisely + + + align:start position:0% +they start at rest that is precisely +right if they start at rest it will + + align:start position:0% +right if they start at rest it will + + + align:start position:0% +right if they start at rest it will +always be equivalent can you think of + + align:start position:0% +always be equivalent can you think of + + + align:start position:0% +always be equivalent can you think of +why they have to be at + + align:start position:0% + + + + align:start position:0% + +rest why do they have to be at rest + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +smile it's not torture + + align:start position:0% + + + + align:start position:0% + +yes so if they weren't at rest the + + align:start position:0% +yes so if they weren't at rest the + + + align:start position:0% +yes so if they weren't at rest the +outputs of the delays wouldn't + + align:start position:0% +outputs of the delays wouldn't + + + align:start position:0% +outputs of the delays wouldn't +necessarily be + + align:start position:0% + + + + align:start position:0% + +zero there is no simple correspondence + + align:start position:0% +zero there is no simple correspondence + + + align:start position:0% +zero there is no simple correspondence +between these two delays and those two + + align:start position:0% + + + + align:start position:0% + +delays if I told you what are these two + + align:start position:0% +delays if I told you what are these two + + + align:start position:0% +delays if I told you what are these two +delays it may or may not be possible to + + align:start position:0% +delays it may or may not be possible to + + + align:start position:0% +delays it may or may not be possible to +make an equivalent system where there + + align:start position:0% +make an equivalent system where there + + + align:start position:0% +make an equivalent system where there +are two different numbers here right say + + align:start position:0% +are two different numbers here right say + + + align:start position:0% +are two different numbers here right say +this out say this delay starts at one + + align:start position:0% +this out say this delay starts at one + + + align:start position:0% +this out say this delay starts at one +and this delay starts at + + align:start position:0% +and this delay starts at + + + align:start position:0% +and this delay starts at +seven there may or may not be a set of + + align:start position:0% +seven there may or may not be a set of + + + align:start position:0% +seven there may or may not be a set of +numbers for the bottom delays that will + + align:start position:0% +numbers for the bottom delays that will + + + align:start position:0% +numbers for the bottom delays that will +have the same + + align:start position:0% +have the same + + + align:start position:0% +have the same +behavior as those numbers did in the top + + align:start position:0% +behavior as those numbers did in the top + + + align:start position:0% +behavior as those numbers did in the top +system okay but what is guaranteed is if + + align:start position:0% +system okay but what is guaranteed is if + + + align:start position:0% +system okay but what is guaranteed is if +they ALS start at zero everything's + + align:start position:0% +they ALS start at zero everything's + + + align:start position:0% +they ALS start at zero everything's +fine that's the reason we put in the + + align:start position:0% +fine that's the reason we put in the + + + align:start position:0% +fine that's the reason we put in the +caveat initially that both systems start + + align:start position:0% +caveat initially that both systems start + + + align:start position:0% +caveat initially that both systems start +at rest the equivalence that we that we + + align:start position:0% +at rest the equivalence that we that we + + + align:start position:0% +at rest the equivalence that we that we +talk about is equivalence starting from + + align:start position:0% +talk about is equivalence starting from + + + align:start position:0% +talk about is equivalence starting from +rest okay so + + align:start position:0% +rest okay so + + + align:start position:0% +rest okay so +uh think about these + + align:start position:0% +uh think about these + + + align:start position:0% +uh think about these +systems they are + + align:start position:0% +systems they are + + + align:start position:0% +systems they are +equivalent you can try to convince + + align:start position:0% +equivalent you can try to convince + + + align:start position:0% +equivalent you can try to convince +yourself they're equivalent by thinking + + align:start position:0% +yourself they're equivalent by thinking + + + align:start position:0% +yourself they're equivalent by thinking +about uh + + align:start position:0% +about uh + + + align:start position:0% +about uh +operations on block + + align:start position:0% +operations on block + + + align:start position:0% +operations on block +diagrams but what I'd like you to think + + align:start position:0% +diagrams but what I'd like you to think + + + align:start position:0% +diagrams but what I'd like you to think +about is they are a statement of what + + align:start position:0% +about is they are a statement of what + + + align:start position:0% +about is they are a statement of what +property of + + align:start position:0% +property of + + + align:start position:0% +property of +pols the equivalence of those two + + align:start position:0% +pols the equivalence of those two + + + align:start position:0% +pols the equivalence of those two +systems is a statement about what + + align:start position:0% +systems is a statement about what + + + align:start position:0% +systems is a statement about what +property of + + align:start position:0% +property of + + + align:start position:0% +property of +pols is it the commutative property the + + align:start position:0% +pols is it the commutative property the + + + align:start position:0% +pols is it the commutative property the +associative property the distributive + + align:start position:0% +associative property the distributive + + + align:start position:0% +associative property the distributive +property the transitive property or none + + align:start position:0% +property the transitive property or none + + + align:start position:0% +property the transitive property or none +of the above + + align:start position:0% + + + + align:start position:0% + +okay you're far too + + align:start position:0% +okay you're far too + + + align:start position:0% +okay you're far too +quiet take a break turn to your neighbor + + align:start position:0% +quiet take a break turn to your neighbor + + + align:start position:0% +quiet take a break turn to your neighbor +tell your neighbor what living group + + align:start position:0% +tell your neighbor what living group + + + align:start position:0% +tell your neighbor what living group +you're + + align:start position:0% +you're + + + align:start position:0% +you're +in become accustomed to talking to your + + align:start position:0% +in become accustomed to talking to your + + + align:start position:0% +in become accustomed to talking to your +neighbor and then figure this out + + align:start position:0% + + + + align:start position:0% + +spe + + align:start position:0% + + + + align:start position:0% + +AAL b means b equals + + align:start position:0% + + + + align:start position:0% + +a or five + + align:start position:0% + + + + align:start position:0% + +okay what property is being dis is being + + align:start position:0% +okay what property is being dis is being + + + align:start position:0% +okay what property is being dis is being +described here everybody raise your hand + + align:start position:0% +described here everybody raise your hand + + + align:start position:0% +described here everybody raise your hand +with some + + align:start position:0% + + + + align:start position:0% + +number excellent excellent more than 90% + + align:start position:0% +number excellent excellent more than 90% + + + align:start position:0% +number excellent excellent more than 90% +correct so the idea is that we write + + align:start position:0% +correct so the idea is that we write + + + align:start position:0% +correct so the idea is that we write +this as an R + + align:start position:0% +this as an R + + + align:start position:0% +this as an R +expression so this system says start + + align:start position:0% +expression so this system says start + + + align:start position:0% +expression so this system says start +with X apply this operator to X it's a + + align:start position:0% +with X apply this operator to X it's a + + + align:start position:0% +with X apply this operator to X it's a +little confusing that one goes left and + + align:start position:0% +little confusing that one goes left and + + + align:start position:0% +little confusing that one goes left and +one goes right right so start with X + + align:start position:0% +one goes right right so start with X + + + align:start position:0% +one goes right right so start with X +apply this to X that's the one minus r + + align:start position:0% +apply this to X that's the one minus r + + + align:start position:0% +apply this to X that's the one minus r +operator then take whatever comes out + + align:start position:0% +operator then take whatever comes out + + + align:start position:0% +operator then take whatever comes out +and apply R + + align:start position:0% +and apply R + + + align:start position:0% +and apply R +again similarly down here start with + + align:start position:0% +again similarly down here start with + + + align:start position:0% +again similarly down here start with +X you've got the sum of two things an r + + align:start position:0% +X you've got the sum of two things an r + + + align:start position:0% +X you've got the sum of two things an r +in the top and an r^ 2 minus one in the + + align:start position:0% +in the top and an r^ 2 minus one in the + + + align:start position:0% +in the top and an r^ 2 minus one in the +bottom and the equivalence of those is + + align:start position:0% +bottom and the equivalence of those is + + + align:start position:0% +bottom and the equivalence of those is +the distributive principle right R + + align:start position:0% +the distributive principle right R + + + align:start position:0% +the distributive principle right R +distributes um so it mult multiplication + + align:start position:0% +distributes um so it mult multiplication + + + align:start position:0% +distributes um so it mult multiplication +over + + align:start position:0% +over + + + align:start position:0% +over +addition + + align:start position:0% + + + + align:start position:0% + +okay okay in the interest of time let me + + align:start position:0% +okay okay in the interest of time let me + + + align:start position:0% +okay okay in the interest of time let me +skip that that's an exercise that you + + align:start position:0% +skip that that's an exercise that you + + + align:start position:0% +skip that that's an exercise that you +can uh work on on your own it's very + + align:start position:0% +can uh work on on your own it's very + + + align:start position:0% +can uh work on on your own it's very +straightforward what I want to do is + + align:start position:0% +straightforward what I want to do is + + + align:start position:0% +straightforward what I want to do is +talk about + + align:start position:0% +talk about + + + align:start position:0% +talk about +another more a slightly deeper + + align:start position:0% +another more a slightly deeper + + + align:start position:0% +another more a slightly deeper +issue and that's the difference between + + align:start position:0% +issue and that's the difference between + + + align:start position:0% +issue and that's the difference between +recipes and constraints for whole block + + align:start position:0% + + + + align:start position:0% + +diagrams so we can think about this as a + + align:start position:0% +diagrams so we can think about this as a + + + align:start position:0% +diagrams so we can think about this as a +recipe in the sense that we can take the + + align:start position:0% +recipe in the sense that we can take the + + + align:start position:0% +recipe in the sense that we can take the +r + + align:start position:0% +r + + + align:start position:0% +r +operators and think about signals as the + + align:start position:0% +operators and think about signals as the + + + align:start position:0% +operators and think about signals as the +composition of other + + align:start position:0% +composition of other + + + align:start position:0% +composition of other +signals so this says take add this + + align:start position:0% +signals so this says take add this + + + align:start position:0% +signals so this says take add this +signal to that signal this signal is + + align:start position:0% +signal to that signal this signal is + + + align:start position:0% +signal to that signal this signal is +just the delay of that signal this + + align:start position:0% +just the delay of that signal this + + + align:start position:0% +just the delay of that signal this +signal is just the minus one of that + + align:start position:0% +signal is just the minus one of that + + + align:start position:0% +signal is just the minus one of that +signal so you can think about there's a + + align:start position:0% +signal so you can think about there's a + + + align:start position:0% +signal so you can think about there's a +recipe start with X invert it delay it + + align:start position:0% +recipe start with X invert it delay it + + + align:start position:0% +recipe start with X invert it delay it +add it to the + + align:start position:0% +add it to the + + + align:start position:0% +add it to the +original that's the + + align:start position:0% +original that's the + + + align:start position:0% +original that's the +output let's contrast that to this this + + align:start position:0% +output let's contrast that to this this + + + align:start position:0% +output let's contrast that to this this +is + + align:start position:0% + + + + align:start position:0% + +harder so let's think about the r + + align:start position:0% +harder so let's think about the r + + + align:start position:0% +harder so let's think about the r +operators what we can say here is that + + align:start position:0% +operators what we can say here is that + + + align:start position:0% +operators what we can say here is that +this output is composed of the sum of + + align:start position:0% +this output is composed of the sum of + + + align:start position:0% +this output is composed of the sum of +two things the input and a delayed + + align:start position:0% +two things the input and a delayed + + + align:start position:0% +two things the input and a delayed +version of the + + align:start position:0% + + + + align:start position:0% + +output that's a recipe for finding the + + align:start position:0% +output that's a recipe for finding the + + + align:start position:0% +output that's a recipe for finding the +input from the + + align:start position:0% + + + + align:start position:0% + +output that's not what we want to + + align:start position:0% +output that's not what we want to + + + align:start position:0% +output that's not what we want to +do so there's a recipe here that says + + align:start position:0% +do so there's a recipe here that says + + + align:start position:0% +do so there's a recipe here that says +start with the + + align:start position:0% +start with the + + + align:start position:0% +start with the +output shift it to the right subtract + + align:start position:0% +output shift it to the right subtract + + + align:start position:0% +output shift it to the right subtract +that from the original and that'll tell + + align:start position:0% +that from the original and that'll tell + + + align:start position:0% +that from the original and that'll tell +you the input but I don't know the + + align:start position:0% +you the input but I don't know the + + + align:start position:0% +you the input but I don't know the +output I know the + + align:start position:0% +output I know the + + + align:start position:0% +output I know the +input what that says is if you knew the + + align:start position:0% +input what that says is if you knew the + + + align:start position:0% +input what that says is if you knew the +output it would have this property it's + + align:start position:0% +output it would have this property it's + + + align:start position:0% +output it would have this property it's +declarative + + align:start position:0% + + + + align:start position:0% + +whatever the output is it has to have + + align:start position:0% +whatever the output is it has to have + + + align:start position:0% +whatever the output is it has to have +that + + align:start position:0% +that + + + align:start position:0% +that +property but it didn't tell me how to + + align:start position:0% +property but it didn't tell me how to + + + align:start position:0% +property but it didn't tell me how to +get + + align:start position:0% +get + + + align:start position:0% +get +it okay the r operator is + + align:start position:0% +it okay the r operator is + + + align:start position:0% +it okay the r operator is +imperative start with the input apply R + + align:start position:0% +imperative start with the input apply R + + + align:start position:0% +imperative start with the input apply R +to it you get the + + align:start position:0% +to it you get the + + + align:start position:0% +to it you get the +output but you can compose + + align:start position:0% +output but you can compose + + + align:start position:0% +output but you can compose +systems using an imperative operator + + align:start position:0% +systems using an imperative operator + + + align:start position:0% +systems using an imperative operator +that is not where the overall system is + + align:start position:0% +that is not where the overall system is + + + align:start position:0% +that is not where the overall system is +not imperative + + align:start position:0% + + + + align:start position:0% + +so what are you going to do with + + align:start position:0% +so what are you going to do with + + + align:start position:0% +so what are you going to do with +something like that well it's a + + align:start position:0% +something like that well it's a + + + align:start position:0% +something like that well it's a +constraint so the question is how do you + + align:start position:0% +constraint so the question is how do you + + + align:start position:0% +constraint so the question is how do you +think about + + align:start position:0% +think about + + + align:start position:0% +think about +that the thing to do in this case is the + + align:start position:0% +that the thing to do in this case is the + + + align:start position:0% +that the thing to do in this case is the +thing you should always do in this + + align:start position:0% +thing you should always do in this + + + align:start position:0% +thing you should always do in this +course fall back to a simpler + + align:start position:0% +course fall back to a simpler + + + align:start position:0% +course fall back to a simpler +method the idea is we're going to start + + align:start position:0% +method the idea is we're going to start + + + align:start position:0% +method the idea is we're going to start +by teaching simple methods and then more + + align:start position:0% +by teaching simple methods and then more + + + align:start position:0% +by teaching simple methods and then more +abstract methods and then more abstract + + align:start position:0% +abstract methods and then more abstract + + + align:start position:0% +abstract methods and then more abstract +methods the reason being that as the + + align:start position:0% +methods the reason being that as the + + + align:start position:0% +methods the reason being that as the +methods become more abstract they become + + align:start position:0% +methods become more abstract they become + + + align:start position:0% +methods become more abstract they become +more powerful you can do things + + align:start position:0% +more powerful you can do things + + + align:start position:0% +more powerful you can do things +quicker but they fail revert to the + + align:start position:0% +quicker but they fail revert to the + + + align:start position:0% +quicker but they fail revert to the +easier method so here the easier method + + align:start position:0% +easier method so here the easier method + + + align:start position:0% +easier method so here the easier method +is sample by + + align:start position:0% +is sample by + + + align:start position:0% +is sample by +sample so let's just think about how + + align:start position:0% +sample so let's just think about how + + + align:start position:0% +sample so let's just think about how +signals would propagate through this + + align:start position:0% +signals would propagate through this + + + align:start position:0% +signals would propagate through this +system so think about this as a sample + + align:start position:0% +system so think about this as a sample + + + align:start position:0% +system so think about this as a sample +by + + align:start position:0% +by + + + align:start position:0% +by +sample uh block diagram + + align:start position:0% +sample uh block diagram + + + align:start position:0% +sample uh block diagram +system say that it starts at rest so the + + align:start position:0% +system say that it starts at rest so the + + + align:start position:0% +system say that it starts at rest so the +initial output so the output at before + + align:start position:0% +initial output so the output at before + + + align:start position:0% +initial output so the output at before +any inputs come in have to be zero + + align:start position:0% +any inputs come in have to be zero + + + align:start position:0% +any inputs come in have to be zero +because the initial condition was that + + align:start position:0% +because the initial condition was that + + + align:start position:0% +because the initial condition was that +delays were all zero + + align:start position:0% +delays were all zero + + + align:start position:0% +delays were all zero +now the input comes in at time + + align:start position:0% +now the input comes in at time + + + align:start position:0% +now the input comes in at time +one so X of0 is one so the output + + align:start position:0% +one so X of0 is one so the output + + + align:start position:0% +one so X of0 is one so the output +becomes + + align:start position:0% +becomes + + + align:start position:0% +becomes +one and now because of the way that + + align:start position:0% +one and now because of the way that + + + align:start position:0% +one and now because of the way that +feedback path + + align:start position:0% +feedback path + + + align:start position:0% +feedback path +works the output there's a second signal + + align:start position:0% +works the output there's a second signal + + + align:start position:0% +works the output there's a second signal +is also the second sample is also + + align:start position:0% +is also the second sample is also + + + align:start position:0% +is also the second sample is also +one did everybody see + + align:start position:0% +one did everybody see + + + align:start position:0% +one did everybody see +that and in fact it's + + align:start position:0% + + + + align:start position:0% + +stuck so the idea in the s this system + + align:start position:0% +stuck so the idea in the s this system + + + align:start position:0% +stuck so the idea in the s this system +if you think about it from a sample by + + align:start position:0% +if you think about it from a sample by + + + align:start position:0% +if you think about it from a sample by +sample point of view the signal at the + + align:start position:0% +sample point of view the signal at the + + + align:start position:0% +sample point of view the signal at the +output persists long in fact infinitely + + align:start position:0% +output persists long in fact infinitely + + + align:start position:0% +output persists long in fact infinitely +long after the signal at the input goes + + align:start position:0% +long after the signal at the input goes + + + align:start position:0% +long after the signal at the input goes +away that's very different from what we + + align:start position:0% +away that's very different from what we + + + align:start position:0% +away that's very different from what we +saw in the simpler systems that were + + align:start position:0% +saw in the simpler systems that were + + + align:start position:0% +saw in the simpler systems that were +imperative if in the previous systems + + align:start position:0% +imperative if in the previous systems + + + align:start position:0% +imperative if in the previous systems +you had a finite length signal at the + + align:start position:0% +you had a finite length signal at the + + + align:start position:0% +you had a finite length signal at the +input any number of operations that you + + align:start position:0% +input any number of operations that you + + + align:start position:0% +input any number of operations that you +did to it and then combine those would + + align:start position:0% +did to it and then combine those would + + + align:start position:0% +did to it and then combine those would +give you a finite length output maybe + + align:start position:0% +give you a finite length output maybe + + + align:start position:0% +give you a finite length output maybe +bigger than the last one because of + + align:start position:0% +bigger than the last one because of + + + align:start position:0% +bigger than the last one because of +extra delays in the system but it's if + + align:start position:0% +extra delays in the system but it's if + + + align:start position:0% +extra delays in the system but it's if +it started finite it's + + align:start position:0% +it started finite it's + + + align:start position:0% +it started finite it's +finite this is different here I'm having + + align:start position:0% +finite this is different here I'm having + + + align:start position:0% +finite this is different here I'm having +a a persisting response persists to + + align:start position:0% +a a persisting response persists to + + + align:start position:0% +a a persisting response persists to +Infinity from a transient input and + + align:start position:0% +Infinity from a transient input and + + + align:start position:0% +Infinity from a transient input and +that's because the uh it's because of + + align:start position:0% +that's because the uh it's because of + + + align:start position:0% +that's because the uh it's because of +feedback it's because there's a path + + align:start position:0% +feedback it's because there's a path + + + align:start position:0% +feedback it's because there's a path +that goes that wraps back on + + align:start position:0% +that goes that wraps back on + + + align:start position:0% +that goes that wraps back on +itself so how can we think how do we + + align:start position:0% +itself so how can we think how do we + + + align:start position:0% +itself so how can we think how do we +think about that in terms of our + + align:start position:0% +think about that in terms of our + + + align:start position:0% +think about that in terms of our +operators well having figured out what + + align:start position:0% +operators well having figured out what + + + align:start position:0% +operators well having figured out what +the response looks like there's a + + align:start position:0% +the response looks like there's a + + + align:start position:0% +the response looks like there's a +perfectly valid R expression for this + + align:start position:0% +perfectly valid R expression for this + + + align:start position:0% +perfectly valid R expression for this +signal this is just the unit + + align:start position:0% +signal this is just the unit + + + align:start position:0% +signal this is just the unit +sample plus r * the unit sample plus r 2 + + align:start position:0% +sample plus r * the unit sample plus r 2 + + + align:start position:0% +sample plus r * the unit sample plus r 2 +time the unit sample plus r Cub time the + + align:start position:0% +time the unit sample plus r Cub time the + + + align:start position:0% +time the unit sample plus r Cub time the +unit sample at infin item that's that + + align:start position:0% +unit sample at infin item that's that + + + align:start position:0% +unit sample at infin item that's that +system okay so I've done something very + + align:start position:0% +system okay so I've done something very + + + align:start position:0% +system okay so I've done something very +powerful and not all that obvious I've + + align:start position:0% +powerful and not all that obvious I've + + + align:start position:0% +powerful and not all that obvious I've +taken a system that was not imperative + + align:start position:0% + + + + align:start position:0% + +and I've turned it into a system that is + + align:start position:0% + + + + align:start position:0% + +imperative this system gives me a recipe + + align:start position:0% +imperative this system gives me a recipe + + + align:start position:0% +imperative this system gives me a recipe +for how to do things start with X delay + + align:start position:0% +for how to do things start with X delay + + + align:start position:0% +for how to do things start with X delay +it by one and add it delay it by another + + align:start position:0% +it by one and add it delay it by another + + + align:start position:0% +it by one and add it delay it by another +one and add it delay it by another one + + align:start position:0% +one and add it delay it by another one + + + align:start position:0% +one and add it delay it by another one +and add it delay it by another one and + + align:start position:0% +and add it delay it by another one and + + + align:start position:0% +and add it delay it by another one and +add it I've converted an A U declarative + + align:start position:0% +add it I've converted an A U declarative + + + align:start position:0% +add it I've converted an A U declarative +statement about how the system should + + align:start position:0% +statement about how the system should + + + align:start position:0% +statement about how the system should +work into an imperative statement about + + align:start position:0% +work into an imperative statement about + + + align:start position:0% +work into an imperative statement about +how the system should work so and I've + + align:start position:0% +how the system should work so and I've + + + align:start position:0% +how the system should work so and I've +got an equivalent system representation + + align:start position:0% +got an equivalent system representation + + + align:start position:0% +got an equivalent system representation +like this + + align:start position:0% +like this + + + align:start position:0% +like this +and you should be saying to yourself do + + align:start position:0% +and you should be saying to yourself do + + + align:start position:0% +and you should be saying to yourself do +I really buy + + align:start position:0% +I really buy + + + align:start position:0% +I really buy +that so is it really going to be the + + align:start position:0% +that so is it really going to be the + + + align:start position:0% +that so is it really going to be the +case that A system that was previously + + align:start position:0% +case that A system that was previously + + + align:start position:0% +case that A system that was previously +described this + + align:start position:0% +described this + + + align:start position:0% +described this +way tell me the + + align:start position:0% +way tell me the + + + align:start position:0% +way tell me the +output operate on it by one minus r and + + align:start position:0% +output operate on it by one minus r and + + + align:start position:0% +output operate on it by one minus r and +that'll be the input should that be the + + align:start position:0% +that'll be the input should that be the + + + align:start position:0% +that'll be the input should that be the +same as this + + align:start position:0% +same as this + + + align:start position:0% +same as this +system if you think about that + + align:start position:0% +system if you think about that + + + align:start position:0% +system if you think about that +mathematically here's a proof it is okay + + align:start position:0% +mathematically here's a proof it is okay + + + align:start position:0% +mathematically here's a proof it is okay +to think about it that way start with + + align:start position:0% +to think about it that way start with + + + align:start position:0% +to think about it that way start with +the idea that X2 = + + align:start position:0% + + + + align:start position:0% + +X1 this is a statement of the right hand + + align:start position:0% +X1 this is a statement of the right hand + + + align:start position:0% +X1 this is a statement of the right hand +side substitute X1 for + + align:start position:0% + + + + align:start position:0% + +X2 substitute this equivalent expression + + align:start position:0% +X2 substitute this equivalent expression + + + align:start position:0% +X2 substitute this equivalent expression +for + + align:start position:0% +for + + + align:start position:0% +for +X1 and multiply it + + align:start position:0% + + + + align:start position:0% + +out when you do that you find Y2 equals + + align:start position:0% +out when you do that you find Y2 equals + + + align:start position:0% +out when you do that you find Y2 equals +y1 it's + + align:start position:0% +y1 it's + + + align:start position:0% +y1 it's +true and what we've done is showed a + + align:start position:0% +true and what we've done is showed a + + + align:start position:0% +true and what we've done is showed a +very important thing this and this are + + align:start position:0% +very important thing this and this are + + + align:start position:0% +very important thing this and this are +reciprocals when you multiply two pols + + align:start position:0% +reciprocals when you multiply two pols + + + align:start position:0% +reciprocals when you multiply two pols +together and the answer is + + align:start position:0% +together and the answer is + + + align:start position:0% +together and the answer is +one they're + + align:start position:0% +one they're + + + align:start position:0% +one they're +reciprocals we so that implies that we + + align:start position:0% +reciprocals we so that implies that we + + + align:start position:0% +reciprocals we so that implies that we +can treat that first expression we can + + align:start position:0% +can treat that first expression we can + + + align:start position:0% +can treat that first expression we can +think about this uh let's see back up so + + align:start position:0% +think about this uh let's see back up so + + + align:start position:0% +think about this uh let's see back up so +here we had an expression that said + + align:start position:0% +here we had an expression that said + + + align:start position:0% +here we had an expression that said +start with the output operate on it with + + align:start position:0% +start with the output operate on it with + + + align:start position:0% +start with the output operate on it with +this get the input we can think about + + align:start position:0% +this get the input we can think about + + + align:start position:0% +this get the input we can think about +that instead as operate on the output + + align:start position:0% +that instead as operate on the output + + + align:start position:0% +that instead as operate on the output +operate on the + + align:start position:0% +operate on the + + + align:start position:0% +operate on the +input by the reciprocal + + align:start position:0% +input by the reciprocal + + + align:start position:0% +input by the reciprocal +operator now I've designed I've defined + + align:start position:0% +operator now I've designed I've defined + + + align:start position:0% +operator now I've designed I've defined +what does reciprocal + + align:start position:0% + + + + align:start position:0% + +mean reciprocal means that thing in the + + align:start position:0% +mean reciprocal means that thing in the + + + align:start position:0% +mean reciprocal means that thing in the +last + + align:start position:0% +last + + + align:start position:0% +last +slide so + + align:start position:0% +slide so + + + align:start position:0% +slide so +now in fact I know from the last Slide + + align:start position:0% +now in fact I know from the last Slide + + + align:start position:0% +now in fact I know from the last Slide +the reciprocal of 1 minus r is 1 plus r + + align:start position:0% +the reciprocal of 1 minus r is 1 plus r + + + align:start position:0% +the reciprocal of 1 minus r is 1 plus r +plus r s plus RB blah blah blah and that + + align:start position:0% +plus r s plus RB blah blah blah and that + + + align:start position:0% +plus r s plus RB blah blah blah and that +follows the normal rules of pooms this + + align:start position:0% +follows the normal rules of pooms this + + + align:start position:0% +follows the normal rules of pooms this +is not a surprise you could have done + + align:start position:0% +is not a surprise you could have done + + + align:start position:0% +is not a surprise you could have done +that you could have derived that same + + align:start position:0% +that you could have derived that same + + + align:start position:0% +that you could have derived that same +expression by thinking about synthetic + + align:start position:0% +expression by thinking about synthetic + + + align:start position:0% +expression by thinking about synthetic +division you could have thought about it + + align:start position:0% +division you could have thought about it + + + align:start position:0% +division you could have thought about it +as a tailor series anything you know + + align:start position:0% +as a tailor series anything you know + + + align:start position:0% +as a tailor series anything you know +about pols should have + + align:start position:0% +about pols should have + + + align:start position:0% +about pols should have +worked so this idea of representing a + + align:start position:0% +worked so this idea of representing a + + + align:start position:0% +worked so this idea of representing a +signal by a system by an operator R is + + align:start position:0% +signal by a system by an operator R is + + + align:start position:0% +signal by a system by an operator R is +extraordinarily + + align:start position:0% +extraordinarily + + + align:start position:0% +extraordinarily +powerful we've been able to take + + align:start position:0% +powerful we've been able to take + + + align:start position:0% +powerful we've been able to take +advantage of non-trivial properties of + + align:start position:0% +advantage of non-trivial properties of + + + align:start position:0% +advantage of non-trivial properties of +pols by having done that and we'll + + align:start position:0% +pols by having done that and we'll + + + align:start position:0% +pols by having done that and we'll +continue that way so the overriding + + align:start position:0% +continue that way so the overriding + + + align:start position:0% +continue that way so the overriding +feature of this system that was not + + align:start position:0% +feature of this system that was not + + + align:start position:0% +feature of this system that was not +uh that could not so this system was not + + align:start position:0% +uh that could not so this system was not + + + align:start position:0% +uh that could not so this system was not +a recipe it was a + + align:start position:0% + + + + align:start position:0% + +constraint the feature that made it that + + align:start position:0% +constraint the feature that made it that + + + align:start position:0% +constraint the feature that made it that +way is something we'll call + + align:start position:0% +way is something we'll call + + + align:start position:0% +way is something we'll call +feedback and we'll be able to visualize + + align:start position:0% +feedback and we'll be able to visualize + + + align:start position:0% +feedback and we'll be able to visualize +feedback very simply by looking at the + + align:start position:0% +feedback very simply by looking at the + + + align:start position:0% +feedback very simply by looking at the +block diagram feedback means that + + align:start position:0% +block diagram feedback means that + + + align:start position:0% +block diagram feedback means that +there's a cycle + + align:start position:0% + + + + align:start position:0% + +somewhere so if there's no Cycles then + + align:start position:0% +somewhere so if there's no Cycles then + + + align:start position:0% +somewhere so if there's no Cycles then +it has to be so we call this the network + + align:start position:0% +it has to be so we call this the network + + + align:start position:0% +it has to be so we call this the network +that results when there's no Cycles we + + align:start position:0% +that results when there's no Cycles we + + + align:start position:0% +that results when there's no Cycles we +say it's a cyclic what a clever word + + align:start position:0% +say it's a cyclic what a clever word + + + align:start position:0% +say it's a cyclic what a clever word +right so no cycles and when it's a + + align:start position:0% +right so no cycles and when it's a + + + align:start position:0% +right so no cycles and when it's a +cyclic it will have the property that + + align:start position:0% +cyclic it will have the property that + + + align:start position:0% +cyclic it will have the property that +transient inputs give rise to transient + + align:start position:0% +transient inputs give rise to transient + + + align:start position:0% +transient inputs give rise to transient +outputs if it has a cycle in it then it + + align:start position:0% +outputs if it has a cycle in it then it + + + align:start position:0% +outputs if it has a cycle in it then it +has feedback and feedback has the + + align:start position:0% +has feedback and feedback has the + + + align:start position:0% +has feedback and feedback has the +potential doesn't always do it but has + + align:start position:0% +potential doesn't always do it but has + + + align:start position:0% +potential doesn't always do it but has +the potential to generate a persisting + + align:start position:0% +the potential to generate a persisting + + + align:start position:0% +the potential to generate a persisting +output to a transient + + align:start position:0% + + + + align:start position:0% + +input so uh if we think about a slightly + + align:start position:0% +input so uh if we think about a slightly + + + align:start position:0% +input so uh if we think about a slightly +more complicated + + align:start position:0% +more complicated + + + align:start position:0% +more complicated +example where I've put a number P not in + + align:start position:0% +example where I've put a number P not in + + + align:start position:0% +example where I've put a number P not in +the feedback loop that was not in the + + align:start position:0% +the feedback loop that was not in the + + + align:start position:0% +the feedback loop that was not in the +previous example we can see that the way + + align:start position:0% +previous example we can see that the way + + + align:start position:0% +previous example we can see that the way +the way you can conceive of this since + + align:start position:0% +the way you can conceive of this since + + + align:start position:0% +the way you can conceive of this since +there's a single time when we're + + align:start position:0% +there's a single time when we're + + + align:start position:0% +there's a single time when we're +thinking about the unit sample response + + align:start position:0% +thinking about the unit sample response + + + align:start position:0% +thinking about the unit sample response +there's a single input that's not + + align:start position:0% +there's a single input that's not + + + align:start position:0% +there's a single input that's not +zero and what you can do is think about + + align:start position:0% +zero and what you can do is think about + + + align:start position:0% +zero and what you can do is think about +the feedback the block diagram you can + + align:start position:0% +the feedback the block diagram you can + + + align:start position:0% +the feedback the block diagram you can +think about it's separating + + align:start position:0% +think about it's separating + + + align:start position:0% +think about it's separating +times because there's a one unit of + + align:start position:0% +times because there's a one unit of + + + align:start position:0% +times because there's a one unit of +delay in every + + align:start position:0% +delay in every + + + align:start position:0% +delay in every +cycle so you can think about that as the + + align:start position:0% +cycle so you can think about that as the + + + align:start position:0% +cycle so you can think about that as the +only way you can get from the input at + + align:start position:0% +only way you can get from the input at + + + align:start position:0% +only way you can get from the input at +Time Zero to the output at Time Zero is + + align:start position:0% +Time Zero to the output at Time Zero is + + + align:start position:0% +Time Zero to the output at Time Zero is +through the straightforward path the one + + align:start position:0% +through the straightforward path the one + + + align:start position:0% +through the straightforward path the one +highlighted by Red the only way you can + + align:start position:0% +highlighted by Red the only way you can + + + align:start position:0% +highlighted by Red the only way you can +get from the input at Time Zero to the + + align:start position:0% +get from the input at Time Zero to the + + + align:start position:0% +get from the input at Time Zero to the +output at time one is to make the circle + + align:start position:0% +output at time one is to make the circle + + + align:start position:0% +output at time one is to make the circle +at least at least once uh to make the + + align:start position:0% +at least at least once uh to make the + + + align:start position:0% +at least at least once uh to make the +circle exactly + + align:start position:0% +circle exactly + + + align:start position:0% +circle exactly +once + + align:start position:0% +once + + + align:start position:0% +once +there if you make the circle exactly + + align:start position:0% +there if you make the circle exactly + + + align:start position:0% +there if you make the circle exactly +once then uh instead of being height one + + align:start position:0% +once then uh instead of being height one + + + align:start position:0% +once then uh instead of being height one +it's height P KN because you had to have + + align:start position:0% +it's height P KN because you had to have + + + align:start position:0% +it's height P KN because you had to have +gone through the P KN + + align:start position:0% + + + + align:start position:0% + +once if you go around a third time it's + + align:start position:0% +once if you go around a third time it's + + + align:start position:0% +once if you go around a third time it's +p^ squar p to the 4th Etc so there's a + + align:start position:0% +p^ squar p to the 4th Etc so there's a + + + align:start position:0% +p^ squar p to the 4th Etc so there's a +way of thinking about + + align:start position:0% + + + + align:start position:0% + +why there why is there this persistent + + align:start position:0% +why there why is there this persistent + + + align:start position:0% +why there why is there this persistent +response by looking at the Block + + align:start position:0% +response by looking at the Block + + + align:start position:0% +response by looking at the Block +diagrams what I'm trying to emphasize is + + align:start position:0% +diagrams what I'm trying to emphasize is + + + align:start position:0% +diagrams what I'm trying to emphasize is +that it's useful to be able to think + + align:start position:0% +that it's useful to be able to think + + + align:start position:0% +that it's useful to be able to think +about differential difference equations + + align:start position:0% +about differential difference equations + + + align:start position:0% +about differential difference equations +block diagrams are operators they're all + + align:start position:0% +block diagrams are operators they're all + + + align:start position:0% +block diagrams are operators they're all +useful what you want to know is the + + align:start position:0% +useful what you want to know is the + + + align:start position:0% +useful what you want to know is the +strengths and limitations of each so + + align:start position:0% +strengths and limitations of each so + + + align:start position:0% +strengths and limitations of each so +here what I've showed is a very good way + + align:start position:0% +here what I've showed is a very good way + + + align:start position:0% +here what I've showed is a very good way +to think + + align:start position:0% +to think + + + align:start position:0% +to think +about feedback + + align:start position:0% +about feedback + + + align:start position:0% +about feedback +in terms of block + + align:start position:0% + + + + align:start position:0% + +diagrams + + align:start position:0% +diagrams + + + align:start position:0% +diagrams +uh how many of these networks are + + align:start position:0% +uh how many of these networks are + + + align:start position:0% +uh how many of these networks are +cyclic how many of these networks are a + + align:start position:0% + + + + align:start position:0% + +cyclic is this cyclic this + + align:start position:0% +cyclic is this cyclic this + + + align:start position:0% +cyclic is this cyclic this +network no so the none of the paths wrap + + align:start position:0% +network no so the none of the paths wrap + + + align:start position:0% +network no so the none of the paths wrap +that back on itself here's a path here's + + align:start position:0% +that back on itself here's a path here's + + + align:start position:0% +that back on itself here's a path here's +a path here's a path none of those wrap + + align:start position:0% +a path here's a path none of those wrap + + + align:start position:0% +a path here's a path none of those wrap +on itself is this network cyclic sure + + align:start position:0% +on itself is this network cyclic sure + + + align:start position:0% +on itself is this network cyclic sure +the this is cyclic over here this one + + align:start position:0% +the this is cyclic over here this one + + + align:start position:0% +the this is cyclic over here this one +yeah the input this is cyclic this one + + align:start position:0% +yeah the input this is cyclic this one + + + align:start position:0% +yeah the input this is cyclic this one +doubly cylic okay so that's the + + align:start position:0% +doubly cylic okay so that's the + + + align:start position:0% +doubly cylic okay so that's the +idea + + align:start position:0% + + + + align:start position:0% + +um and this gives rise to a notion that + + align:start position:0% +um and this gives rise to a notion that + + + align:start position:0% +um and this gives rise to a notion that +we will call a + + align:start position:0% + + + + align:start position:0% + +pole a pole is the base of the geometric + + align:start position:0% +pole a pole is the base of the geometric + + + align:start position:0% +pole a pole is the base of the geometric +sequence that results in these simple + + align:start position:0% +sequence that results in these simple + + + align:start position:0% +sequence that results in these simple +sequences + + align:start position:0% +sequences + + + align:start position:0% +sequences +whenever you have + + align:start position:0% +whenever you have + + + align:start position:0% +whenever you have +feedback and we'll be saying a whole lot + + align:start position:0% +feedback and we'll be saying a whole lot + + + align:start position:0% +feedback and we'll be saying a whole lot +more about those uh in upcoming + + align:start position:0% +more about those uh in upcoming + + + align:start position:0% +more about those uh in upcoming +times um in the interest of time I I + + align:start position:0% +times um in the interest of time I I + + + align:start position:0% +times um in the interest of time I I +have to stop now but so the idea from + + align:start position:0% +have to stop now but so the idea from + + + align:start position:0% +have to stop now but so the idea from +today is supposed to have + + align:start position:0% +today is supposed to have + + + align:start position:0% +today is supposed to have +been lots of representations for DT + + align:start position:0% +been lots of representations for DT + + + align:start position:0% +been lots of representations for DT +signals that DT signals and + + align:start position:0% +signals that DT signals and + + + align:start position:0% +signals that DT signals and +systems strengths and weaknesses of each + + align:start position:0% +systems strengths and weaknesses of each + + + align:start position:0% +systems strengths and weaknesses of each +difference equations concise + + align:start position:0% +difference equations concise + + + align:start position:0% +difference equations concise +precise block diagrams visualizing + + align:start position:0% +precise block diagrams visualizing + + + align:start position:0% +precise block diagrams visualizing +signal flow + + align:start position:0% +signal flow + + + align:start position:0% +signal flow +paths operators thinking about things as + + align:start position:0% +paths operators thinking about things as + + + align:start position:0% +paths operators thinking about things as +polinomial and what we'll do in the next + + align:start position:0% +polinomial and what we'll do in the next + + + align:start position:0% +polinomial and what we'll do in the next +few sessions is try to build on that + + align:start position:0% +few sessions is try to build on that + + + align:start position:0% +few sessions is try to build on that +polinomial representation to gain + + align:start position:0% +polinomial representation to gain + + + align:start position:0% +polinomial representation to gain +further insights into the way that + + align:start position:0% +further insights into the way that + + + align:start position:0% +further insights into the way that +systems will + + align:start position:0% +systems will + + + align:start position:0% +systems will +work thank you \ No newline at end of file diff --git a/IkpQJSDK940.txt b/IkpQJSDK940.txt new file mode 100644 index 0000000000000000000000000000000000000000..a3b956421a75437fc1326d1492ecf59d41b1e9a1 --- /dev/null +++ b/IkpQJSDK940.txt @@ -0,0 +1,5955 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +view additional materials from hundreds + + align:start position:0% +view additional materials from hundreds + + + align:start position:0% +view additional materials from hundreds +of MIT courses visit mitop courseware at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu hi today we're going to to + + align:start position:0% +ocw.mit.edu hi today we're going to to + + + align:start position:0% +ocw.mit.edu hi today we're going to to +begin our study of higher order + + align:start position:0% +begin our study of higher order + + + align:start position:0% +begin our study of higher order +differential equations in particular + + align:start position:0% +differential equations in particular + + + align:start position:0% +differential equations in particular +we're going to talk about a special + + align:start position:0% +we're going to talk about a special + + + align:start position:0% +we're going to talk about a special +equation called the linear differential + + align:start position:0% +equation called the linear differential + + + align:start position:0% +equation called the linear differential +equation which came up by the way you'll + + align:start position:0% +equation which came up by the way you'll + + + align:start position:0% +equation which came up by the way you'll +notice in first order equations as a + + align:start position:0% +notice in first order equations as a + + + align:start position:0% +notice in first order equations as a +special type but we're going to + + align:start position:0% +special type but we're going to + + + align:start position:0% +special type but we're going to +generalize that and the only Liberty I'm + + align:start position:0% +generalize that and the only Liberty I'm + + + align:start position:0% +generalize that and the only Liberty I'm +going to take during the lecture is to + + align:start position:0% +going to take during the lecture is to + + + align:start position:0% +going to take during the lecture is to +restrict our study to the case of + + align:start position:0% +restrict our study to the case of + + + align:start position:0% +restrict our study to the case of +differential equations of order two so + + align:start position:0% +differential equations of order two so + + + align:start position:0% +differential equations of order two so +that we won't have unwieldy Expressions + + align:start position:0% +that we won't have unwieldy Expressions + + + align:start position:0% +that we won't have unwieldy Expressions +all over the board the idea is that what + + align:start position:0% +all over the board the idea is that what + + + align:start position:0% +all over the board the idea is that what +happen s in the case of Nal 2 happens + + align:start position:0% +happen s in the case of Nal 2 happens + + + align:start position:0% +happen s in the case of Nal 2 happens +for all orders n except for a little + + align:start position:0% +for all orders n except for a little + + + align:start position:0% +for all orders n except for a little +modification in the algebra but we'll + + align:start position:0% +modification in the algebra but we'll + + + align:start position:0% +modification in the algebra but we'll +talk about that more in the exercises at + + align:start position:0% +talk about that more in the exercises at + + + align:start position:0% +talk about that more in the exercises at +any rate for the time being we simply + + align:start position:0% +any rate for the time being we simply + + + align:start position:0% +any rate for the time being we simply +call today's lecture linear differential + + align:start position:0% +call today's lecture linear differential + + + align:start position:0% +call today's lecture linear differential +equations and now I must Define for you + + align:start position:0% +equations and now I must Define for you + + + align:start position:0% +equations and now I must Define for you +what I mean by a linear differential + + align:start position:0% +what I mean by a linear differential + + + align:start position:0% +what I mean by a linear differential +equation and I'll motivate this more as + + align:start position:0% +equation and I'll motivate this more as + + + align:start position:0% +equation and I'll motivate this more as +we go along for the time being a linear + + align:start position:0% +we go along for the time being a linear + + + align:start position:0% +we go along for the time being a linear +differential equation is simply one + + align:start position:0% +differential equation is simply one + + + align:start position:0% +differential equation is simply one +which has this very special form what + + align:start position:0% +which has this very special form what + + + align:start position:0% +which has this very special form what +you have is a a y Prime term appearing + + align:start position:0% +you have is a a y Prime term appearing + + + align:start position:0% +you have is a a y Prime term appearing +then some function of X alone + + align:start position:0% +then some function of X alone + + + align:start position:0% +then some function of X alone +multiplying y prime plus some function + + align:start position:0% +multiplying y prime plus some function + + + align:start position:0% +multiplying y prime plus some function +of X alone multiplying Y and on the + + align:start position:0% +of X alone multiplying Y and on the + + + align:start position:0% +of X alone multiplying Y and on the +right some function of X alone and an + + align:start position:0% +right some function of X alone and an + + + align:start position:0% +right some function of X alone and an +analogous result would hold for higher + + align:start position:0% +analogous result would hold for higher + + + align:start position:0% +analogous result would hold for higher +order in other words you have the + + align:start position:0% +order in other words you have the + + + align:start position:0% +order in other words you have the +various derivatives of Y appearing y by + + align:start position:0% +various derivatives of Y appearing y by + + + align:start position:0% +various derivatives of Y appearing y by +itself the coefficients are always + + align:start position:0% +itself the coefficients are always + + + align:start position:0% +itself the coefficients are always +functions of X alone and no power is or + + align:start position:0% +functions of X alone and no power is or + + + align:start position:0% +functions of X alone and no power is or +no derivative or Y is raised to any + + align:start position:0% +no derivative or Y is raised to any + + + align:start position:0% +no derivative or Y is raised to any +power in particular notice here it's a + + align:start position:0% +power in particular notice here it's a + + + align:start position:0% +power in particular notice here it's a +very small point but notice here that I + + align:start position:0% +very small point but notice here that I + + + align:start position:0% +very small point but notice here that I +assume that the leading coefficient here + + align:start position:0% +assume that the leading coefficient here + + + align:start position:0% +assume that the leading coefficient here +is one for example somebody might have + + align:start position:0% +is one for example somebody might have + + + align:start position:0% +is one for example somebody might have +said couldn't you have had some function + + align:start position:0% +said couldn't you have had some function + + + align:start position:0% +said couldn't you have had some function +of x * y Prime the answer is yes I could + + align:start position:0% +of x * y Prime the answer is yes I could + + + align:start position:0% +of x * y Prime the answer is yes I could +have but I'm assuming that if I had a + + align:start position:0% +have but I'm assuming that if I had a + + + align:start position:0% +have but I'm assuming that if I had a +function say R ofx multiplying y Prime I + + align:start position:0% +function say R ofx multiplying y Prime I + + + align:start position:0% +function say R ofx multiplying y Prime I +could have multiplied both divided both + + align:start position:0% +could have multiplied both divided both + + + align:start position:0% +could have multiplied both divided both +sides of this equation through by that + + align:start position:0% +sides of this equation through by that + + + align:start position:0% +sides of this equation through by that +coefficient and wound up with an + + align:start position:0% +coefficient and wound up with an + + + align:start position:0% +coefficient and wound up with an +equation of this particular type another + + align:start position:0% +equation of this particular type another + + + align:start position:0% +equation of this particular type another +without loss of generality and this is + + align:start position:0% +without loss of generality and this is + + + align:start position:0% +without loss of generality and this is +very important though many of my + + align:start position:0% +very important though many of my + + + align:start position:0% +very important though many of my +theorems are going to be messed up a + + align:start position:0% +theorems are going to be messed up a + + + align:start position:0% +theorems are going to be messed up a +little bit if the coefficient of Y + + align:start position:0% +little bit if the coefficient of Y + + + align:start position:0% +little bit if the coefficient of Y +double Prime isn't one in other words + + align:start position:0% +double Prime isn't one in other words + + + align:start position:0% +double Prime isn't one in other words +the algebra will become a little bit + + align:start position:0% +the algebra will become a little bit + + + align:start position:0% +the algebra will become a little bit +tougher I'll speak about that later in + + align:start position:0% +tougher I'll speak about that later in + + + align:start position:0% +tougher I'll speak about that later in +the lecture if I remember to but the + + align:start position:0% +the lecture if I remember to but the + + + align:start position:0% +the lecture if I remember to but the +idea is for the time being this is all + + align:start position:0% +idea is for the time being this is all + + + align:start position:0% +idea is for the time being this is all +we mean by a linear differential + + align:start position:0% +we mean by a linear differential + + + align:start position:0% +we mean by a linear differential +equation and perhaps the best way to + + align:start position:0% +equation and perhaps the best way to + + + align:start position:0% +equation and perhaps the best way to +emphasize what we really mean by linear + + align:start position:0% +emphasize what we really mean by linear + + + align:start position:0% +emphasize what we really mean by linear +differential equation is to show what we + + align:start position:0% +differential equation is to show what we + + + align:start position:0% +differential equation is to show what we +mean by a nonlinear differential + + align:start position:0% +mean by a nonlinear differential + + + align:start position:0% +mean by a nonlinear differential +equation a differential equ equation + + align:start position:0% +equation a differential equ equation + + + align:start position:0% +equation a differential equ equation +which is not linear for example y Prime + + align:start position:0% +which is not linear for example y Prime + + + align:start position:0% +which is not linear for example y Prime ++ y Prime 2 + y = sinx would not be a + + align:start position:0% ++ y Prime 2 + y = sinx would not be a + + + align:start position:0% ++ y Prime 2 + y = sinx would not be a +linear equation because the Y Prime term + + align:start position:0% +linear equation because the Y Prime term + + + align:start position:0% +linear equation because the Y Prime term +is being raised to a power other than + + align:start position:0% +is being raised to a power other than + + + align:start position:0% +is being raised to a power other than +the first Power see it's squid y Prime + + + align:start position:0% +the first Power see it's squid y Prime + + + + align:start position:0% +the first Power see it's squid y Prime + +y * y Prime = e x is not a linear + + align:start position:0% +y * y Prime = e x is not a linear + + + align:start position:0% +y * y Prime = e x is not a linear +equation because the multiplier of Y + + align:start position:0% +equation because the multiplier of Y + + + align:start position:0% +equation because the multiplier of Y +Prime is y as opposed to just a function + + align:start position:0% +Prime is y as opposed to just a function + + + align:start position:0% +Prime is y as opposed to just a function +of X which is what the definition calls + + align:start position:0% +of X which is what the definition calls + + + align:start position:0% +of X which is what the definition calls +for y Prime + XY Prime + y^2 = x Cub is + + align:start position:0% +for y Prime + XY Prime + y^2 = x Cub is + + + align:start position:0% +for y Prime + XY Prime + y^2 = x Cub is +not linear and the reason that it's not + + align:start position:0% +not linear and the reason that it's not + + + align:start position:0% +not linear and the reason that it's not +linear is because y appears to a power + + align:start position:0% +linear is because y appears to a power + + + align:start position:0% +linear is because y appears to a power +higher than the first maybe I should + + align:start position:0% +higher than the first maybe I should + + + align:start position:0% +higher than the first maybe I should +Circle the things that prevent these + + align:start position:0% +Circle the things that prevent these + + + align:start position:0% +Circle the things that prevent these +things from being linear so that you can + + align:start position:0% +things from being linear so that you can + + + align:start position:0% +things from being linear so that you can +see what's happening here y Prime + e x + + align:start position:0% +see what's happening here y Prime + e x + + + align:start position:0% +see what's happening here y Prime + e x +y Prime + x Cub y = tan Y is not linear + + align:start position:0% +y Prime + x Cub y = tan Y is not linear + + + align:start position:0% +y Prime + x Cub y = tan Y is not linear +because even though the left hand side + + align:start position:0% +because even though the left hand side + + + align:start position:0% +because even though the left hand side +is fine notice that the function on the + + align:start position:0% +is fine notice that the function on the + + + align:start position:0% +is fine notice that the function on the +right hand side is a function of Y + + align:start position:0% +right hand side is a function of Y + + + align:start position:0% +right hand side is a function of Y +depends on y rather than just X + + align:start position:0% +depends on y rather than just X + + + align:start position:0% +depends on y rather than just X +alone and to finish this off an example + + align:start position:0% +alone and to finish this off an example + + + align:start position:0% +alone and to finish this off an example +of a linear equation would be what well + + align:start position:0% +of a linear equation would be what well + + + align:start position:0% +of a linear equation would be what well +almost this one y prime plus e x y Prime + + align:start position:0% +almost this one y prime plus e x y Prime + + + align:start position:0% +almost this one y prime plus e x y Prime ++ x Cub y equal tangent X you see a y + + align:start position:0% ++ x Cub y equal tangent X you see a y + + + align:start position:0% ++ x Cub y equal tangent X you see a y +Prime term y Prime to the first power + + align:start position:0% +Prime term y Prime to the first power + + + align:start position:0% +Prime term y Prime to the first power +being multiplied by a function of X + + align:start position:0% +being multiplied by a function of X + + + align:start position:0% +being multiplied by a function of X +alone y to the first power being + + align:start position:0% +alone y to the first power being + + + align:start position:0% +alone y to the first power being +multiplied by by a function of X alone + + align:start position:0% +multiplied by by a function of X alone + + + align:start position:0% +multiplied by by a function of X alone +and the right hand side being a function + + align:start position:0% +and the right hand side being a function + + + align:start position:0% +and the right hand side being a function +of X explicitly by itself and notice by + + align:start position:0% +of X explicitly by itself and notice by + + + align:start position:0% +of X explicitly by itself and notice by +the way don't get caught in a + + align:start position:0% +the way don't get caught in a + + + align:start position:0% +the way don't get caught in a +psychological hangup here when I say + + align:start position:0% +psychological hangup here when I say + + + align:start position:0% +psychological hangup here when I say +linear it's I'm modifying the equation + + align:start position:0% +linear it's I'm modifying the equation + + + align:start position:0% +linear it's I'm modifying the equation +not what the coefficients look like in + + align:start position:0% +not what the coefficients look like in + + + align:start position:0% +not what the coefficients look like in +other words certainly we don't think of + + align:start position:0% +other words certainly we don't think of + + + align:start position:0% +other words certainly we don't think of +e to the X as a linear function we don't + + align:start position:0% +e to the X as a linear function we don't + + + align:start position:0% +e to the X as a linear function we don't +think of X cubed as being linear we + + align:start position:0% +think of X cubed as being linear we + + + align:start position:0% +think of X cubed as being linear we +don't think of tangent X as being linear + + align:start position:0% +don't think of tangent X as being linear + + + align:start position:0% +don't think of tangent X as being linear +the coefficients do not have to be + + align:start position:0% +the coefficients do not have to be + + + align:start position:0% +the coefficients do not have to be +linear functions of x they have to be + + align:start position:0% +linear functions of x they have to be + + + align:start position:0% +linear functions of x they have to be +functions of X alone it's the equation + + align:start position:0% +functions of X alone it's the equation + + + align:start position:0% +functions of X alone it's the equation +that's called linear and maybe the best + + align:start position:0% +that's called linear and maybe the best + + + align:start position:0% +that's called linear and maybe the best +way to explain that is in the following + + align:start position:0% +way to explain that is in the following + + + align:start position:0% +way to explain that is in the following +way let's look at y prime plus P of X Y + + align:start position:0% +way let's look at y prime plus P of X Y + + + align:start position:0% +way let's look at y prime plus P of X Y +prime plus q ofx y my claim is I can + + align:start position:0% +prime plus q ofx y my claim is I can + + + align:start position:0% +prime plus q ofx y my claim is I can +think of this as a function machine + + align:start position:0% +think of this as a function machine + + + align:start position:0% +think of this as a function machine +where the input is y and the Machine is + + align:start position:0% +where the input is y and the Machine is + + + align:start position:0% +where the input is y and the Machine is +told look at whatever y comes in + + align:start position:0% +told look at whatever y comes in + + + align:start position:0% +told look at whatever y comes in +differentiate it twice add on P of x * + + align:start position:0% +differentiate it twice add on P of x * + + + align:start position:0% +differentiate it twice add on P of x * +the first derivative plus Q ofx * the + + align:start position:0% +the first derivative plus Q ofx * the + + + align:start position:0% +the first derivative plus Q ofx * the +function and that will be the output in + + align:start position:0% +function and that will be the output in + + + align:start position:0% +function and that will be the output in +other words I could think of a machine + + align:start position:0% +other words I could think of a machine + + + align:start position:0% +other words I could think of a machine +where the input of the machine is y and + + align:start position:0% +where the input of the machine is y and + + + align:start position:0% +where the input of the machine is y and +let me call the machine the L machine to + + align:start position:0% +let me call the machine the L machine to + + + align:start position:0% +let me call the machine the L machine to +emphasize the word linear see what L + + align:start position:0% +emphasize the word linear see what L + + + align:start position:0% +emphasize the word linear see what L +does is this the domain of L are + + align:start position:0% +does is this the domain of L are + + + align:start position:0% +does is this the domain of L are +functions which are twice differentiable + + align:start position:0% +functions which are twice differentiable + + + align:start position:0% +functions which are twice differentiable +after all to for this to make sense I + + align:start position:0% +after all to for this to make sense I + + + align:start position:0% +after all to for this to make sense I +have to be able to differentiate Y at + + align:start position:0% +have to be able to differentiate Y at + + + align:start position:0% +have to be able to differentiate Y at +least twice so the input of the L + + align:start position:0% +least twice so the input of the L + + + align:start position:0% +least twice so the input of the L +machine is a twice differentiable + + align:start position:0% +machine is a twice differentiable + + + align:start position:0% +machine is a twice differentiable +function of X and the output is some + + align:start position:0% +function of X and the output is some + + + align:start position:0% +function of X and the output is some +function of X you see y Prime y Prime + + align:start position:0% +function of X you see y Prime y Prime + + + align:start position:0% +function of X you see y Prime y Prime +are functions of x p and Q are functions + + align:start position:0% +are functions of x p and Q are functions + + + align:start position:0% +are functions of x p and Q are functions +of X Y is a function of X all these + + align:start position:0% +of X Y is a function of X all these + + + align:start position:0% +of X Y is a function of X all these +things combine them to give you a + + align:start position:0% +things combine them to give you a + + + align:start position:0% +things combine them to give you a +function of X let me show you how this + + align:start position:0% +function of X let me show you how this + + + align:start position:0% +function of X let me show you how this +machine works for example if the L + + align:start position:0% +machine works for example if the L + + + align:start position:0% +machine works for example if the L +machine is y prime plus e the X Y Prime + + align:start position:0% +machine is y prime plus e the X Y Prime + + + align:start position:0% +machine is y prime plus e the X Y Prime ++ x Cub y see other was L of y equals + + align:start position:0% ++ x Cub y see other was L of y equals + + + align:start position:0% ++ x Cub y see other was L of y equals +this if I feed in sinx to the L machine + + align:start position:0% +this if I feed in sinx to the L machine + + + align:start position:0% +this if I feed in sinx to the L machine +what does the L machine do it takes sinx + + align:start position:0% +what does the L machine do it takes sinx + + + align:start position:0% +what does the L machine do it takes sinx +it differentiates it twice adds on e x * + + align:start position:0% +it differentiates it twice adds on e x * + + + align:start position:0% +it differentiates it twice adds on e x * +the first derivative and X Cub time the + + align:start position:0% +the first derivative and X Cub time the + + + align:start position:0% +the first derivative and X Cub time the +function itself which is sinx going + + align:start position:0% +function itself which is sinx going + + + align:start position:0% +function itself which is sinx going +through this operation which is Trivial + + align:start position:0% +through this operation which is Trivial + + + align:start position:0% +through this operation which is Trivial +L of sinx would be X Cub - 1 sinx plus e + + align:start position:0% +L of sinx would be X Cub - 1 sinx plus e + + + align:start position:0% +L of sinx would be X Cub - 1 sinx plus e +x cine X by the way to help you + + align:start position:0% +x cine X by the way to help you + + + align:start position:0% +x cine X by the way to help you +understand what we mean by a solution + + align:start position:0% +understand what we mean by a solution + + + align:start position:0% +understand what we mean by a solution +notice that what we're saying is that if + + align:start position:0% +notice that what we're saying is that if + + + align:start position:0% +notice that what we're saying is that if +we were to refer back to this particular + + align:start position:0% +we were to refer back to this particular + + + align:start position:0% +we were to refer back to this particular +equation Y = sinx would not be a + + align:start position:0% +equation Y = sinx would not be a + + + align:start position:0% +equation Y = sinx would not be a +solution of this equation because when I + + align:start position:0% +solution of this equation because when I + + + align:start position:0% +solution of this equation because when I +feed sinx into the L machine I do not + + align:start position:0% +feed sinx into the L machine I do not + + + align:start position:0% +feed sinx into the L machine I do not +get tangent X which is what a solution + + align:start position:0% +get tangent X which is what a solution + + + align:start position:0% +get tangent X which is what a solution +would mean in other words in terms of + + align:start position:0% +would mean in other words in terms of + + + align:start position:0% +would mean in other words in terms of +our new notation this says L of y equals + + align:start position:0% +our new notation this says L of y equals + + + align:start position:0% +our new notation this says L of y equals +Tan x so anything which is a solution + + align:start position:0% +Tan x so anything which is a solution + + + align:start position:0% +Tan x so anything which is a solution +means if I shove in y to the machine the + + align:start position:0% +means if I shove in y to the machine the + + + align:start position:0% +means if I shove in y to the machine the +output would have to be Tan x to look at + + align:start position:0% +output would have to be Tan x to look at + + + align:start position:0% +output would have to be Tan x to look at +this from a different perspective if the + + align:start position:0% +this from a different perspective if the + + + align:start position:0% +this from a different perspective if the +right hand side of my equation had been + + align:start position:0% +right hand side of my equation had been + + + align:start position:0% +right hand side of my equation had been +this in other words if Tan x had been + + align:start position:0% +this in other words if Tan x had been + + + align:start position:0% +this in other words if Tan x had been +replaced by X Cub - 1 sinx plus e x cinx + + align:start position:0% +replaced by X Cub - 1 sinx plus e x cinx + + + align:start position:0% +replaced by X Cub - 1 sinx plus e x cinx +then y = sinx would have been a solution + + align:start position:0% +then y = sinx would have been a solution + + + align:start position:0% +then y = sinx would have been a solution +of this particular equation but enough + + align:start position:0% +of this particular equation but enough + + + align:start position:0% +of this particular equation but enough +about that and we'll emphasize that more + + align:start position:0% +about that and we'll emphasize that more + + + align:start position:0% +about that and we'll emphasize that more +in the exercises the key Point as to why + + align:start position:0% +in the exercises the key Point as to why + + + align:start position:0% +in the exercises the key Point as to why +the word linear is used is that linear + + align:start position:0% +the word linear is used is that linear + + + align:start position:0% +the word linear is used is that linear +modifies our L machine not the + + align:start position:0% +modifies our L machine not the + + + align:start position:0% +modifies our L machine not the +coefficients of the differential + + align:start position:0% +coefficients of the differential + + + align:start position:0% +coefficients of the differential +equation see what did linear mean when + + align:start position:0% +equation see what did linear mean when + + + align:start position:0% +equation see what did linear mean when +we were dealing with ordinary linear + + align:start position:0% +we were dealing with ordinary linear + + + align:start position:0% +we were dealing with ordinary linear +change of variables back in Block four + + align:start position:0% +change of variables back in Block four + + + align:start position:0% +change of variables back in Block four +of the course when we talked about U = + + align:start position:0% +of the course when we talked about U = + + + align:start position:0% +of the course when we talked about U = +ax + b y and talked about linear + + align:start position:0% +ax + b y and talked about linear + + + align:start position:0% +ax + b y and talked about linear +approximations linear meant if the + + align:start position:0% +approximations linear meant if the + + + align:start position:0% +approximations linear meant if the +mapping was linear L of a constant times + + align:start position:0% +mapping was linear L of a constant times + + + align:start position:0% +mapping was linear L of a constant times +the input would be the constant time L + + align:start position:0% +the input would be the constant time L + + + align:start position:0% +the input would be the constant time L +of the input in other words you could + + align:start position:0% +of the input in other words you could + + + align:start position:0% +of the input in other words you could +Factor the constant out notice by the + + align:start position:0% +Factor the constant out notice by the + + + align:start position:0% +Factor the constant out notice by the +way if I Fe if I feed CU into my L + + align:start position:0% +way if I Fe if I feed CU into my L + + + align:start position:0% +way if I Fe if I feed CU into my L +machine what will the output be see be + + align:start position:0% +machine what will the output be see be + + + align:start position:0% +machine what will the output be see be +very careful here don't be blinded by + + align:start position:0% +very careful here don't be blinded by + + + align:start position:0% +very careful here don't be blinded by +the y y stands for the for the + + align:start position:0% +the y y stands for the for the + + + align:start position:0% +the y y stands for the for the +placeholder the input in other words L + + align:start position:0% +placeholder the input in other words L + + + align:start position:0% +placeholder the input in other words L +of anything is the second derivative of + + align:start position:0% +of anything is the second derivative of + + + align:start position:0% +of anything is the second derivative of +that anything plus P * the first + + align:start position:0% +that anything plus P * the first + + + align:start position:0% +that anything plus P * the first +derivative plus Q times that input the + + align:start position:0% +derivative plus Q times that input the + + + align:start position:0% +derivative plus Q times that input the +anything that I put in here so notice + + align:start position:0% +anything that I put in here so notice + + + align:start position:0% +anything that I put in here so notice +that L of Cu would be the quantity CU + + align:start position:0% +that L of Cu would be the quantity CU + + + align:start position:0% +that L of Cu would be the quantity CU +prime plus P of x * CU prime plus Q ofx + + align:start position:0% +prime plus P of x * CU prime plus Q ofx + + + align:start position:0% +prime plus P of x * CU prime plus Q ofx +* CU in other words L of Cu is equal to + + align:start position:0% +* CU in other words L of Cu is equal to + + + align:start position:0% +* CU in other words L of Cu is equal to +this expression here notice that + + align:start position:0% +this expression here notice that + + + align:start position:0% +this expression here notice that +different differentiating a constant + + align:start position:0% +different differentiating a constant + + + align:start position:0% +different differentiating a constant +times a function of X means that we skip + + align:start position:0% +times a function of X means that we skip + + + align:start position:0% +times a function of X means that we skip +over the constant and just differentiate + + align:start position:0% +over the constant and just differentiate + + + align:start position:0% +over the constant and just differentiate +the function of X in other words + + align:start position:0% +the function of X in other words + + + align:start position:0% +the function of X in other words +differentiating this twice would just be + + align:start position:0% +differentiating this twice would just be + + + align:start position:0% +differentiating this twice would just be +the constant time uble Prime I can take + + align:start position:0% +the constant time uble Prime I can take + + + align:start position:0% +the constant time uble Prime I can take +the constant out here I can take the + + align:start position:0% +the constant out here I can take the + + + align:start position:0% +the constant out here I can take the +constant out here in other words C + + align:start position:0% +constant out here in other words C + + + align:start position:0% +constant out here in other words C +factors out that's where linearity comes + + align:start position:0% +factors out that's where linearity comes + + + align:start position:0% +factors out that's where linearity comes +in this is linear in c i factored the C + + align:start position:0% +in this is linear in c i factored the C + + + align:start position:0% +in this is linear in c i factored the C +out what's left is What U prime plus p u + + align:start position:0% +out what's left is What U prime plus p u + + + align:start position:0% +out what's left is What U prime plus p u +Prime + q u that's what we're calling L + + align:start position:0% +Prime + q u that's what we're calling L + + + align:start position:0% +Prime + q u that's what we're calling L +of U so L of C * U is C * L of U which + + align:start position:0% +of U so L of C * U is C * L of U which + + + align:start position:0% +of U so L of C * U is C * L of U which +is a linear property and by the way + + align:start position:0% +is a linear property and by the way + + + align:start position:0% +is a linear property and by the way +again let me emphasize why linearity + + align:start position:0% +again let me emphasize why linearity + + + align:start position:0% +again let me emphasize why linearity +definition was given the way it was for + + align:start position:0% +definition was given the way it was for + + + align:start position:0% +definition was given the way it was for +example I just say here that it's not + + align:start position:0% +example I just say here that it's not + + + align:start position:0% +example I just say here that it's not +true if nonlinear but for example + + align:start position:0% +true if nonlinear but for example + + + align:start position:0% +true if nonlinear but for example +suppose I had an equation that had y + + align:start position:0% +suppose I had an equation that had y + + + align:start position:0% +suppose I had an equation that had y +Prime multiplied by a function of Y + + align:start position:0% +Prime multiplied by a function of Y + + + align:start position:0% +Prime multiplied by a function of Y +rather than a function of X in other + + align:start position:0% +rather than a function of X in other + + + align:start position:0% +rather than a function of X in other +words let's look at L of y equals y * y + + align:start position:0% +words let's look at L of y equals y * y + + + align:start position:0% +words let's look at L of y equals y * y +Prime if I now replace y by C * U this + + align:start position:0% +Prime if I now replace y by C * U this + + + align:start position:0% +Prime if I now replace y by C * U this +becomes what Y is replaced by C * u y + + align:start position:0% +becomes what Y is replaced by C * u y + + + align:start position:0% +becomes what Y is replaced by C * u y +Prime is replaced by the derivative of + + align:start position:0% +Prime is replaced by the derivative of + + + align:start position:0% +Prime is replaced by the derivative of +Cu well what is the derivative of Cu U + + align:start position:0% +Cu well what is the derivative of Cu U + + + align:start position:0% +Cu well what is the derivative of Cu U +if C is a constant it's C * U Prime in + + align:start position:0% +if C is a constant it's C * U Prime in + + + align:start position:0% +if C is a constant it's C * U Prime in +other words the right hand side here is + + align:start position:0% +other words the right hand side here is + + + align:start position:0% +other words the right hand side here is +just c^ 2 U * U Prime U * U Prime is L + + align:start position:0% +just c^ 2 U * U Prime U * U Prime is L + + + align:start position:0% +just c^ 2 U * U Prime U * U Prime is L +of U in other words in this example L of + + align:start position:0% +of U in other words in this example L of + + + align:start position:0% +of U in other words in this example L of +cuu would not be c l of U it would be C + + align:start position:0% + + + + align:start position:0% + +squid L of U which is not the linear + + align:start position:0% +squid L of U which is not the linear + + + align:start position:0% +squid L of U which is not the linear +property that we're talking about + + align:start position:0% +property that we're talking about + + + align:start position:0% +property that we're talking about +finally the other property of linearity + + align:start position:0% +finally the other property of linearity + + + align:start position:0% +finally the other property of linearity +is that if U if I replace my input by + + align:start position:0% +is that if U if I replace my input by + + + align:start position:0% +is that if U if I replace my input by +the sum of two differentiable functions + + align:start position:0% +the sum of two differentiable functions + + + align:start position:0% +the sum of two differentiable functions +U1 and U2 that L of U1 + U2 turns out to + + align:start position:0% +U1 and U2 that L of U1 + U2 turns out to + + + align:start position:0% +U1 and U2 that L of U1 + U2 turns out to +be L of U1 plus L of U2 and the proof + + align:start position:0% +be L of U1 plus L of U2 and the proof + + + align:start position:0% +be L of U1 plus L of U2 and the proof +again is just by looking at the + + align:start position:0% +again is just by looking at the + + + align:start position:0% +again is just by looking at the +definition if I feed U1 plus U2 into my + + align:start position:0% +definition if I feed U1 plus U2 into my + + + align:start position:0% +definition if I feed U1 plus U2 into my +L machine I have what U1 plus U2 prime + + align:start position:0% +L machine I have what U1 plus U2 prime + + + align:start position:0% +L machine I have what U1 plus U2 prime +plus P of x * U 1 + U2 prime plus Q of x + + align:start position:0% +plus P of x * U 1 + U2 prime plus Q of x + + + align:start position:0% +plus P of x * U 1 + U2 prime plus Q of x +* U1 + U2 the derivative of the sum is a + + align:start position:0% +* U1 + U2 the derivative of the sum is a + + + align:start position:0% +* U1 + U2 the derivative of the sum is a +sum of the derivatives so I can split + + align:start position:0% +sum of the derivatives so I can split + + + align:start position:0% +sum of the derivatives so I can split +this up into U1 prime plus U2 Prime + + align:start position:0% +this up into U1 prime plus U2 Prime + + + align:start position:0% +this up into U1 prime plus U2 Prime +similarly this is p U1 Prime P U2 Prime + + align:start position:0% +similarly this is p U1 Prime P U2 Prime + + + align:start position:0% +similarly this is p U1 Prime P U2 Prime +this is q1 qu2 I break down the U1 terms + + align:start position:0% +this is q1 qu2 I break down the U1 terms + + + align:start position:0% +this is q1 qu2 I break down the U1 terms +together the U2 terms together this by + + align:start position:0% +together the U2 terms together this by + + + align:start position:0% +together the U2 terms together this by +definition is L of + + align:start position:0% +definition is L of + + + align:start position:0% +definition is L of +U1 this by definition of l is L of U2 in + + align:start position:0% +U1 this by definition of l is L of U2 in + + + align:start position:0% +U1 this by definition of l is L of U2 in +other words l L of U1 + U2 is L of U1 + + align:start position:0% +other words l L of U1 + U2 is L of U1 + + + align:start position:0% +other words l L of U1 + U2 is L of U1 +plus L of U2 by the way conditions 1 and + + align:start position:0% +plus L of U2 by the way conditions 1 and + + + align:start position:0% +plus L of U2 by the way conditions 1 and +two can be stated equivalently by the + + align:start position:0% +two can be stated equivalently by the + + + align:start position:0% +two can be stated equivalently by the +one statement L of C1 U1 plus C2 U2 is + + align:start position:0% +one statement L of C1 U1 plus C2 U2 is + + + align:start position:0% +one statement L of C1 U1 plus C2 U2 is +C1 L of U1 plus C2 L of U2 the proof + + align:start position:0% +C1 L of U1 plus C2 L of U2 the proof + + + align:start position:0% +C1 L of U1 plus C2 L of U2 the proof +will be left as an exercise it's a + + align:start position:0% +will be left as an exercise it's a + + + align:start position:0% +will be left as an exercise it's a +fairly trivial observation and I think + + align:start position:0% +fairly trivial observation and I think + + + align:start position:0% +fairly trivial observation and I think +as I you may remember that we did + + align:start position:0% +as I you may remember that we did + + + align:start position:0% +as I you may remember that we did +something at least similar to this in + + align:start position:0% +something at least similar to this in + + + align:start position:0% +something at least similar to this in +Block four when we talked about linear + + align:start position:0% +Block four when we talked about linear + + + align:start position:0% +Block four when we talked about linear +mappings when we were mapping the XY + + align:start position:0% +mappings when we were mapping the XY + + + align:start position:0% +mappings when we were mapping the XY +plane into the UV plane okay but at any + + align:start position:0% +plane into the UV plane okay but at any + + + align:start position:0% +plane into the UV plane okay but at any +rate let's see what all this means why + + align:start position:0% +rate let's see what all this means why + + + align:start position:0% +rate let's see what all this means why +why are these properties so important + + align:start position:0% +why are these properties so important + + + align:start position:0% +why are these properties so important +and so let's call our next sub subtopic + + align:start position:0% +and so let's call our next sub subtopic + + + align:start position:0% +and so let's call our next sub subtopic +properties of linear equations and the + + align:start position:0% +properties of linear equations and the + + + align:start position:0% +properties of linear equations and the +first thing that I'd like to point out + + align:start position:0% +first thing that I'd like to point out + + + align:start position:0% +first thing that I'd like to point out +is that if the right hand side of our + + align:start position:0% +is that if the right hand side of our + + + align:start position:0% +is that if the right hand side of our +linear differential equation is zero the + + align:start position:0% +linear differential equation is zero the + + + align:start position:0% +linear differential equation is zero the +interesting fact is that any linear + + align:start position:0% +interesting fact is that any linear + + + align:start position:0% +interesting fact is that any linear +combination of solutions of that + + align:start position:0% +combination of solutions of that + + + align:start position:0% +combination of solutions of that +equation is again a solution and in + + align:start position:0% +equation is again a solution and in + + + align:start position:0% +equation is again a solution and in +other words if I find some function U1 + + align:start position:0% +other words if I find some function U1 + + + align:start position:0% +other words if I find some function U1 +of X that satisfies the equation L of y + + align:start position:0% +of X that satisfies the equation L of y + + + align:start position:0% +of X that satisfies the equation L of y +equals 0 in other words L of U1 is 0 and + + align:start position:0% +equals 0 in other words L of U1 is 0 and + + + align:start position:0% +equals 0 in other words L of U1 is 0 and +I also know that L of U2 is zero then + + align:start position:0% +I also know that L of U2 is zero then + + + align:start position:0% +I also know that L of U2 is zero then +the amazing thing is that L of C1 U1 + + align:start position:0% +the amazing thing is that L of C1 U1 + + + align:start position:0% +the amazing thing is that L of C1 U1 +plus C2 U2 is also zero in other words + + align:start position:0% +plus C2 U2 is also zero in other words + + + align:start position:0% +plus C2 U2 is also zero in other words +any linear combination of U1 and U2 + + align:start position:0% +any linear combination of U1 and U2 + + + align:start position:0% +any linear combination of U1 and U2 +where U1 and U2 are solutions of L of y + + align:start position:0% +where U1 and U2 are solutions of L of y + + + align:start position:0% +where U1 and U2 are solutions of L of y +equals 0 will also be a solution of L of + + align:start position:0% +equals 0 will also be a solution of L of + + + align:start position:0% +equals 0 will also be a solution of L of +y equal 0 and the proof again is trivial + + align:start position:0% +y equal 0 and the proof again is trivial + + + align:start position:0% +y equal 0 and the proof again is trivial +namely by Def by the properties of + + align:start position:0% +namely by Def by the properties of + + + align:start position:0% +namely by Def by the properties of +linearity L of C1 U1 plus C2 U2 is what + + align:start position:0% +linearity L of C1 U1 plus C2 U2 is what + + + align:start position:0% +linearity L of C1 U1 plus C2 U2 is what +it's C1 L of U1 plus C2 L of U2 L of U1 + + align:start position:0% +it's C1 L of U1 plus C2 L of U2 L of U1 + + + align:start position:0% +it's C1 L of U1 plus C2 L of U2 L of U1 +is zero L of U2 is zero that was given + + align:start position:0% +is zero L of U2 is zero that was given + + + align:start position:0% +is zero L of U2 is zero that was given +you see consequently this is zero see a + + align:start position:0% +you see consequently this is zero see a + + + align:start position:0% +you see consequently this is zero see a +constant time0 plus a constant time 0 is + + align:start position:0% +constant time0 plus a constant time 0 is + + + align:start position:0% +constant time0 plus a constant time 0 is +zero and that's exactly what we wanted + + align:start position:0% +zero and that's exactly what we wanted + + + align:start position:0% +zero and that's exactly what we wanted +to show over here a second important + + align:start position:0% +to show over here a second important + + + align:start position:0% +to show over here a second important +factor is that if I have a solution of L + + align:start position:0% +factor is that if I have a solution of L + + + align:start position:0% +factor is that if I have a solution of L +yal 0 say l of U is z and I also have a + + align:start position:0% +yal 0 say l of U is z and I also have a + + + align:start position:0% +yal 0 say l of U is z and I also have a +solution V of the equation L of yal f + + align:start position:0% +solution V of the equation L of yal f + + + align:start position:0% +solution V of the equation L of yal f +ofx in other words if L of U is zero and + + align:start position:0% +ofx in other words if L of U is zero and + + + align:start position:0% +ofx in other words if L of U is zero and +L of V is f ofx the amazing thing is + + align:start position:0% +L of V is f ofx the amazing thing is + + + align:start position:0% +L of V is f ofx the amazing thing is +that if I add these two solutions + + align:start position:0% +that if I add these two solutions + + + align:start position:0% +that if I add these two solutions +together the resulting function will be + + align:start position:0% +together the resulting function will be + + + align:start position:0% +together the resulting function will be +a solution of the equation L of yal f + + align:start position:0% +a solution of the equation L of yal f + + + align:start position:0% +a solution of the equation L of yal f +ofx in other words if L of U is z and L + + align:start position:0% +ofx in other words if L of U is z and L + + + align:start position:0% +ofx in other words if L of U is z and L +of V is f ofx then L of U + V is also + + align:start position:0% +of V is f ofx then L of U + V is also + + + align:start position:0% +of V is f ofx then L of U + V is also +equal to F ofx what this means is that + + align:start position:0% +equal to F ofx what this means is that + + + align:start position:0% +equal to F ofx what this means is that +whenever I add on to a solution of this + + align:start position:0% +whenever I add on to a solution of this + + + align:start position:0% +whenever I add on to a solution of this +equation any solution of this equation I + + align:start position:0% +equation any solution of this equation I + + + align:start position:0% +equation any solution of this equation I +again get back a solution of this + + align:start position:0% +again get back a solution of this + + + align:start position:0% +again get back a solution of this +equation the proof Again by definition + + align:start position:0% +equation the proof Again by definition + + + align:start position:0% +equation the proof Again by definition +of linearity is Trivial namely by + + align:start position:0% +of linearity is Trivial namely by + + + align:start position:0% +of linearity is Trivial namely by +linearity L of U + V is L of U plus L of + + align:start position:0% +linearity L of U + V is L of U plus L of + + + align:start position:0% +linearity L of U + V is L of U plus L of +V but we're given that L of U is z we're + + align:start position:0% +V but we're given that L of U is z we're + + + align:start position:0% +V but we're given that L of U is z we're +given that L of V is f ofx and + + align:start position:0% +given that L of V is f ofx and + + + align:start position:0% +given that L of V is f ofx and +consequently 0 plus f of x X is f ofx so + + align:start position:0% +consequently 0 plus f of x X is f ofx so + + + align:start position:0% +consequently 0 plus f of x X is f ofx so +L of U plus v is f ofx as asserted by + + align:start position:0% +L of U plus v is f ofx as asserted by + + + align:start position:0% +L of U plus v is f ofx as asserted by +the way let me point out here do not + + align:start position:0% +the way let me point out here do not + + + align:start position:0% +the way let me point out here do not +Overlook the power of + + align:start position:0% +Overlook the power of + + + align:start position:0% +Overlook the power of +linearity there is a very big danger + + align:start position:0% +linearity there is a very big danger + + + align:start position:0% +linearity there is a very big danger +that what you might say here is wasn't + + align:start position:0% +that what you might say here is wasn't + + + align:start position:0% +that what you might say here is wasn't +this result true just by adding equals + + align:start position:0% +this result true just by adding equals + + + align:start position:0% +this result true just by adding equals +to equals in other words couldn't I just + + align:start position:0% +to equals in other words couldn't I just + + + align:start position:0% +to equals in other words couldn't I just +add these two results and the answer is + + align:start position:0% +add these two results and the answer is + + + align:start position:0% +add these two results and the answer is +yes you can but when you add equals to + + align:start position:0% +yes you can but when you add equals to + + + align:start position:0% +yes you can but when you add equals to +equals here notice that what you get is + + align:start position:0% +equals here notice that what you get is + + + align:start position:0% +equals here notice that what you get is +what L of U plus L of V is equal to 0 + + + align:start position:0% +what L of U plus L of V is equal to 0 + + + + align:start position:0% +what L of U plus L of V is equal to 0 + +f ofx in other words what you can prove + + align:start position:0% +f ofx in other words what you can prove + + + align:start position:0% +f ofx in other words what you can prove +by equals added to equals is that L of U + + align:start position:0% +by equals added to equals is that L of U + + + align:start position:0% +by equals added to equals is that L of U +plus L of V is f ofx it was linearity + + align:start position:0% +plus L of V is f ofx it was linearity + + + align:start position:0% +plus L of V is f ofx it was linearity +that allowed us to say that L of U plus + + align:start position:0% +that allowed us to say that L of U plus + + + align:start position:0% +that allowed us to say that L of U plus +L of V was the same as L of U plus v and + + align:start position:0% +L of V was the same as L of U plus v and + + + align:start position:0% +L of V was the same as L of U plus v and +to show you that in terms of a simple + + align:start position:0% +to show you that in terms of a simple + + + align:start position:0% +to show you that in terms of a simple +analogy let's suppose I take the + + align:start position:0% +analogy let's suppose I take the + + + align:start position:0% +analogy let's suppose I take the +function f to be defined by F ofx is X - + + align:start position:0% +function f to be defined by F ofx is X - + + + align:start position:0% +function f to be defined by F ofx is X - +2 * x - 3 well trivially when X is 2 or + + align:start position:0% +2 * x - 3 well trivially when X is 2 or + + + align:start position:0% +2 * x - 3 well trivially when X is 2 or +X is three f ofx is zero right other + + align:start position:0% +X is three f ofx is zero right other + + + align:start position:0% +X is three f ofx is zero right other +words F of two is z f of 3 is zero Now + + align:start position:0% +words F of two is z f of 3 is zero Now + + + align:start position:0% +words F of two is z f of 3 is zero Now +by equals added to equals you can + + align:start position:0% +by equals added to equals you can + + + align:start position:0% +by equals added to equals you can +certainly say that F of 2 plus f of3 is + + align:start position:0% +certainly say that F of 2 plus f of3 is + + + align:start position:0% +certainly say that F of 2 plus f of3 is +zero but you can't say that F of the + + align:start position:0% +zero but you can't say that F of the + + + align:start position:0% +zero but you can't say that F of the +quantity 2 + 3 is zero in fact 2 + 3 is + + align:start position:0% +quantity 2 + 3 is zero in fact 2 + 3 is + + + align:start position:0% +quantity 2 + 3 is zero in fact 2 + 3 is +five if I put five in here I get what F + + align:start position:0% +five if I put five in here I get what F + + + align:start position:0% +five if I put five in here I get what F +of 5 is 5 - 2 * 5 - 3 that's 3 * 2 or 6 + + align:start position:0% +of 5 is 5 - 2 * 5 - 3 that's 3 * 2 or 6 + + + align:start position:0% +of 5 is 5 - 2 * 5 - 3 that's 3 * 2 or 6 +in other words F of 2 + f of 3 is z but + + align:start position:0% +in other words F of 2 + f of 3 is z but + + + align:start position:0% +in other words F of 2 + f of 3 is z but +F of 2 + 3 is not zero it's 6 you see + + align:start position:0% +F of 2 + 3 is not zero it's 6 you see + + + align:start position:0% +F of 2 + 3 is not zero it's 6 you see +equals added to equals gives you this + + align:start position:0% +equals added to equals gives you this + + + align:start position:0% +equals added to equals gives you this +result but it's linearity that you need + + align:start position:0% +result but it's linearity that you need + + + align:start position:0% +result but it's linearity that you need +to be able to get from here to here this + + align:start position:0% +to be able to get from here to here this + + + align:start position:0% +to be able to get from here to here this +was not a linear function you see well + + align:start position:0% +was not a linear function you see well + + + align:start position:0% +was not a linear function you see well +let me give you an example of how to use + + align:start position:0% +let me give you an example of how to use + + + align:start position:0% +let me give you an example of how to use +all this stuff let's find all solutions + + align:start position:0% +all this stuff let's find all solutions + + + align:start position:0% +all this stuff let's find all solutions +of the differential equation Y Prime - 4 + + align:start position:0% +of the differential equation Y Prime - 4 + + + align:start position:0% +of the differential equation Y Prime - 4 +y Prime + 3 y = Z special case where the + + align:start position:0% +y Prime + 3 y = Z special case where the + + + align:start position:0% +y Prime + 3 y = Z special case where the +right hand side is zero my coefficients + + align:start position:0% +right hand side is zero my coefficients + + + align:start position:0% +right hand side is zero my coefficients +of Y and Y Prime notice are still + + align:start position:0% +of Y and Y Prime notice are still + + + align:start position:0% +of Y and Y Prime notice are still +functions of X they happen to be + + align:start position:0% +functions of X they happen to be + + + align:start position:0% +functions of X they happen to be +constant but the requirement that P of x + + align:start position:0% +constant but the requirement that P of x + + + align:start position:0% +constant but the requirement that P of x +and q of X be constants is certainly not + + align:start position:0% +and q of X be constants is certainly not + + + align:start position:0% +and q of X be constants is certainly not +outlawed in other words one special case + + align:start position:0% +outlawed in other words one special case + + + align:start position:0% +outlawed in other words one special case +of a function of X is the function of X + + align:start position:0% +of a function of X is the function of X + + + align:start position:0% +of a function of X is the function of X +which is identically a constant so this + + align:start position:0% +which is identically a constant so this + + + align:start position:0% +which is identically a constant so this +qualifies as a linear equation let me + + align:start position:0% +qualifies as a linear equation let me + + + align:start position:0% +qualifies as a linear equation let me +show you then how I try to find all + + align:start position:0% +show you then how I try to find all + + + align:start position:0% +show you then how I try to find all +solutions of this equation as we've + + align:start position:0% +solutions of this equation as we've + + + align:start position:0% +solutions of this equation as we've +mentioned before both in part one of our + + align:start position:0% +mentioned before both in part one of our + + + align:start position:0% +mentioned before both in part one of our +course and as a motivation for defining + + align:start position:0% +course and as a motivation for defining + + + align:start position:0% +course and as a motivation for defining +e to the iix a trial solution of this + + align:start position:0% +e to the iix a trial solution of this + + + align:start position:0% +e to the iix a trial solution of this +equation involves using e to the RX + + align:start position:0% +equation involves using e to the RX + + + align:start position:0% +equation involves using e to the RX +because when you differentiate e to the + + align:start position:0% +because when you differentiate e to the + + + align:start position:0% +because when you differentiate e to the +RX you get e to the RX back again if I + + align:start position:0% +RX you get e to the RX back again if I + + + align:start position:0% +RX you get e to the RX back again if I +differentiate e to the RX I get r e to + + align:start position:0% +differentiate e to the RX I get r e to + + + align:start position:0% +differentiate e to the RX I get r e to +the RX differentiate again I get R 2 e + + align:start position:0% +the RX differentiate again I get R 2 e + + + align:start position:0% +the RX differentiate again I get R 2 e +to the RX I plug that into here factor + + align:start position:0% +to the RX I plug that into here factor + + + align:start position:0% +to the RX I plug that into here factor +out the e to the RX and I wind up with e + + align:start position:0% +out the e to the RX and I wind up with e + + + align:start position:0% +out the e to the RX and I wind up with e +to the RX * r^ 2 - 4 r + 3 must equal Z + + align:start position:0% +to the RX * r^ 2 - 4 r + 3 must equal Z + + + align:start position:0% +to the RX * r^ 2 - 4 r + 3 must equal Z +since e to the RX is not zero it must be + + align:start position:0% +since e to the RX is not zero it must be + + + align:start position:0% +since e to the RX is not zero it must be +that r^ 2 - 4 r + 3 is zero and that + + align:start position:0% +that r^ 2 - 4 r + 3 is zero and that + + + align:start position:0% +that r^ 2 - 4 r + 3 is zero and that +says that either R is 1 or R is three + + align:start position:0% +says that either R is 1 or R is three + + + align:start position:0% +says that either R is 1 or R is three +remembering what R is it means that my + + align:start position:0% +remembering what R is it means that my + + + align:start position:0% +remembering what R is it means that my +trial Solutions should be correct when R + + align:start position:0% +trial Solutions should be correct when R + + + align:start position:0% +trial Solutions should be correct when R +is one or R is three leaving the details + + align:start position:0% +is one or R is three leaving the details + + + align:start position:0% +is one or R is three leaving the details +for you to verify it does turn out that + + align:start position:0% +for you to verify it does turn out that + + + align:start position:0% +for you to verify it does turn out that +L of e to the x is z see R is 1 L of e + + align:start position:0% +L of e to the x is z see R is 1 L of e + + + align:start position:0% +L of e to the x is z see R is 1 L of e +to 3x R is3 is zero in other words if I + + align:start position:0% +to 3x R is3 is zero in other words if I + + + align:start position:0% +to 3x R is3 is zero in other words if I +were to replace y by E to X or by E to + + align:start position:0% +were to replace y by E to X or by E to + + + align:start position:0% +were to replace y by E to X or by E to +3x this equation is satisfied and in + + align:start position:0% +3x this equation is satisfied and in + + + align:start position:0% +3x this equation is satisfied and in +terms of our definition of l this is the + + align:start position:0% +terms of our definition of l this is the + + + align:start position:0% +terms of our definition of l this is the +abbreviation for writing this well by + + align:start position:0% +abbreviation for writing this well by + + + align:start position:0% +abbreviation for writing this well by +our first property the fact that this + + align:start position:0% +our first property the fact that this + + + align:start position:0% +our first property the fact that this +satisfies L of yals 0 and this satisfies + + align:start position:0% +satisfies L of yals 0 and this satisfies + + + align:start position:0% +satisfies L of yals 0 and this satisfies +L of y equals 0 we had what any linear + + align:start position:0% +L of y equals 0 we had what any linear + + + align:start position:0% +L of y equals 0 we had what any linear +combination of these two must satisfy L + + align:start position:0% +combination of these two must satisfy L + + + align:start position:0% +combination of these two must satisfy L +of y equal 0 in other words I now know + + align:start position:0% +of y equal 0 in other words I now know + + + align:start position:0% +of y equal 0 in other words I now know +in one Fell Swoop that every function of + + align:start position:0% +in one Fell Swoop that every function of + + + align:start position:0% +in one Fell Swoop that every function of +the form C1 e to X Plus C2 e to 3x must + + align:start position:0% +the form C1 e to X Plus C2 e to 3x must + + + align:start position:0% +the form C1 e to X Plus C2 e to 3x must +also be a solution of this equation okay + + align:start position:0% +also be a solution of this equation okay + + + align:start position:0% +also be a solution of this equation okay +by the way that's another motivation and + + align:start position:0% +by the way that's another motivation and + + + align:start position:0% +by the way that's another motivation and +why we'll be doing this in block a for + + align:start position:0% +why we'll be doing this in block a for + + + align:start position:0% +why we'll be doing this in block a for +going further into the study of vector + + align:start position:0% +going further into the study of vector + + + align:start position:0% +going further into the study of vector +spaces notice in a sense what you're + + align:start position:0% +spaces notice in a sense what you're + + + align:start position:0% +spaces notice in a sense what you're +saying is you have found a whole family + + align:start position:0% +saying is you have found a whole family + + + align:start position:0% +saying is you have found a whole family +of solutions which are linear + + align:start position:0% +of solutions which are linear + + + align:start position:0% +of solutions which are linear +combinations of e to the X and E to 3x + + align:start position:0% +combinations of e to the X and E to 3x + + + align:start position:0% +combinations of e to the X and E to 3x +that somehow or other e to 3x and e to + + align:start position:0% +that somehow or other e to 3x and e to + + + align:start position:0% +that somehow or other e to 3x and e to +the X behave like I and J did in the + + align:start position:0% +the X behave like I and J did in the + + + align:start position:0% +the X behave like I and J did in the +plane namely every solution of this type + + align:start position:0% +plane namely every solution of this type + + + align:start position:0% +plane namely every solution of this type +can be written as what a constant time e + + align:start position:0% +can be written as what a constant time e + + + align:start position:0% +can be written as what a constant time e +to X plus a constant time e to 3x this + + align:start position:0% +to X plus a constant time e to 3x this + + + align:start position:0% +to X plus a constant time e to 3x this +is like a two-dimensional Vector space + + align:start position:0% +is like a two-dimensional Vector space + + + align:start position:0% +is like a two-dimensional Vector space +but I'm not going to pursue that any + + align:start position:0% +but I'm not going to pursue that any + + + align:start position:0% +but I'm not going to pursue that any +further right now I just want to give + + align:start position:0% +further right now I just want to give + + + align:start position:0% +further right now I just want to give +you a preview of Coming Attractions but + + align:start position:0% +you a preview of Coming Attractions but + + + align:start position:0% +you a preview of Coming Attractions but +at any rate to summarize what we've done + + align:start position:0% +at any rate to summarize what we've done + + + align:start position:0% +at any rate to summarize what we've done +so far is that we have now found that + + align:start position:0% +so far is that we have now found that + + + align:start position:0% +so far is that we have now found that +one family of solutions of that equation + + align:start position:0% +one family of solutions of that equation + + + align:start position:0% +one family of solutions of that equation +is y = C1 e to X plus c 2 e to 3x I + + align:start position:0% +is y = C1 e to X plus c 2 e to 3x I + + + align:start position:0% +is y = C1 e to X plus c 2 e to 3x I +emphasize one family because so far + + align:start position:0% +emphasize one family because so far + + + align:start position:0% +emphasize one family because so far +these are the solutions I found by + + align:start position:0% +these are the solutions I found by + + + align:start position:0% +these are the solutions I found by +assuming that the solution had to have + + align:start position:0% +assuming that the solution had to have + + + align:start position:0% +assuming that the solution had to have +the form Y is e to the RX I don't know + + align:start position:0% +the form Y is e to the RX I don't know + + + align:start position:0% +the form Y is e to the RX I don't know +as yet whether there are other types of + + align:start position:0% +as yet whether there are other types of + + + align:start position:0% +as yet whether there are other types of +solutions I'll worry about that in a + + align:start position:0% +solutions I'll worry about that in a + + + align:start position:0% +solutions I'll worry about that in a +little while at any rate the next most + + align:start position:0% +little while at any rate the next most + + + align:start position:0% +little while at any rate the next most +natural question to ask here is this + + align:start position:0% +natural question to ask here is this + + + align:start position:0% +natural question to ask here is this +look at I have two arbitrary constants + + align:start position:0% +look at I have two arbitrary constants + + + align:start position:0% +look at I have two arbitrary constants +and because I have two arbitrary + + align:start position:0% +and because I have two arbitrary + + + align:start position:0% +and because I have two arbitrary +constants it seems to me that just like + + align:start position:0% +constants it seems to me that just like + + + align:start position:0% +constants it seems to me that just like +in the first order case not only should + + align:start position:0% +in the first order case not only should + + + align:start position:0% +in the first order case not only should +I be able to find a solution that passes + + align:start position:0% +I be able to find a solution that passes + + + align:start position:0% +I be able to find a solution that passes +through a particular point but I have + + align:start position:0% +through a particular point but I have + + + align:start position:0% +through a particular point but I have +another degree of freedom to play around + + align:start position:0% +another degree of freedom to play around + + + align:start position:0% +another degree of freedom to play around +with maybe I can require not only that + + align:start position:0% +with maybe I can require not only that + + + align:start position:0% +with maybe I can require not only that +the curve passes through a given point + + align:start position:0% +the curve passes through a given point + + + align:start position:0% +the curve passes through a given point +but that it have a particular slope when + + align:start position:0% +but that it have a particular slope when + + + align:start position:0% +but that it have a particular slope when +it passes through that point in other + + align:start position:0% +it passes through that point in other + + + align:start position:0% +it passes through that point in other +words with one constant I could make it + + align:start position:0% +words with one constant I could make it + + + align:start position:0% +words with one constant I could make it +pass through a point with two maybe I + + align:start position:0% +pass through a point with two maybe I + + + align:start position:0% +pass through a point with two maybe I +could make it pass through a point + + align:start position:0% +could make it pass through a point + + + align:start position:0% +could make it pass through a point +having a given slope so the question now + + align:start position:0% +having a given slope so the question now + + + align:start position:0% +having a given slope so the question now +is can I + + align:start position:0% +is can I + + + align:start position:0% +is can I +determine C1 and C2 such that for a + + align:start position:0% +determine C1 and C2 such that for a + + + align:start position:0% +determine C1 and C2 such that for a +given point x0 y0 I can find a curve a + + align:start position:0% +given point x0 y0 I can find a curve a + + + align:start position:0% +given point x0 y0 I can find a curve a +member of this family which passes + + align:start position:0% +member of this family which passes + + + align:start position:0% +member of this family which passes +through the point x0 y0 and has slope + + align:start position:0% +through the point x0 y0 and has slope + + + align:start position:0% +through the point x0 y0 and has slope +equal to z0 why I use z0 instead of M + + align:start position:0% +equal to z0 why I use z0 instead of M + + + align:start position:0% +equal to z0 why I use z0 instead of M +here will become clear I hope in a few + + align:start position:0% +here will become clear I hope in a few + + + align:start position:0% +here will become clear I hope in a few +moments but the point is to see if I can + + align:start position:0% +moments but the point is to see if I can + + + align:start position:0% +moments but the point is to see if I can +satisfy this system of equations let's + + align:start position:0% +satisfy this system of equations let's + + + align:start position:0% +satisfy this system of equations let's +see what happens if I replace X and Y by + + align:start position:0% +see what happens if I replace X and Y by + + + align:start position:0% +see what happens if I replace X and Y by +x0 and y0 one of my equations that must + + align:start position:0% +x0 and y0 one of my equations that must + + + align:start position:0% +x0 and y0 one of my equations that must +be satisfied by C1 and C2 is this + + align:start position:0% +be satisfied by C1 and C2 is this + + + align:start position:0% +be satisfied by C1 and C2 is this +the derivative of this which is a slope + + align:start position:0% +the derivative of this which is a slope + + + align:start position:0% +the derivative of this which is a slope +is C1 e to X+ 3 C2 e 3x so if the slope + + align:start position:0% +is C1 e to X+ 3 C2 e 3x so if the slope + + + align:start position:0% +is C1 e to X+ 3 C2 e 3x so if the slope +is going to be z0 when X is equal to x0 + + align:start position:0% +is going to be z0 when X is equal to x0 + + + align:start position:0% +is going to be z0 when X is equal to x0 +this equation must also be obeyed + + align:start position:0% +this equation must also be obeyed + + + align:start position:0% +this equation must also be obeyed +consequently I must now solve see if I + + align:start position:0% +consequently I must now solve see if I + + + align:start position:0% +consequently I must now solve see if I +can solve these two equations for C1 and + + align:start position:0% +can solve these two equations for C1 and + + + align:start position:0% +can solve these two equations for C1 and +C2 by the way this is very important to + + align:start position:0% +C2 by the way this is very important to + + + align:start position:0% +C2 by the way this is very important to +notice notice that this is two equations + + align:start position:0% +notice notice that this is two equations + + + align:start position:0% +notice notice that this is two equations +and two unknowns and that my unknowns + + align:start position:0% +and two unknowns and that my unknowns + + + align:start position:0% +and two unknowns and that my unknowns +are C1 and C2 that once I specify x0 y0 + + align:start position:0% +are C1 and C2 that once I specify x0 y0 + + + align:start position:0% +are C1 and C2 that once I specify x0 y0 +and z0 everything else is a known number + + align:start position:0% +and z0 everything else is a known number + + + align:start position:0% +and z0 everything else is a known number +in this problem to see whether this has + + align:start position:0% +in this problem to see whether this has + + + align:start position:0% +in this problem to see whether this has +a unique solution the determinant of + + align:start position:0% +a unique solution the determinant of + + + align:start position:0% +a unique solution the determinant of +coefficients must be unequal to zero but + + align:start position:0% +coefficients must be unequal to zero but + + + align:start position:0% +coefficients must be unequal to zero but +look at what the determinant of + + align:start position:0% +look at what the determinant of + + + align:start position:0% +look at what the determinant of +coefficients is it's ex0 e 3x0 e x0 3 e + + align:start position:0% +coefficients is it's ex0 e 3x0 e x0 3 e + + + align:start position:0% +coefficients is it's ex0 e 3x0 e x0 3 e +3x0 that determinant is what 3 e to 4X 0 + + align:start position:0% +3x0 that determinant is what 3 e to 4X 0 + + + align:start position:0% +3x0 that determinant is what 3 e to 4X 0 +minus E to 4X 0 that's twice e to 4X Z + + align:start position:0% +minus E to 4X 0 that's twice e to 4X Z + + + align:start position:0% +minus E to 4X 0 that's twice e to 4X Z +and since the exponential can never be + + align:start position:0% +and since the exponential can never be + + + align:start position:0% +and since the exponential can never be +negative this can never be zero this + + align:start position:0% +negative this can never be zero this + + + align:start position:0% +negative this can never be zero this +determinant cannot be zero in other + + align:start position:0% +determinant cannot be zero in other + + + align:start position:0% +determinant cannot be zero in other +words there is a unique member of the + + align:start position:0% +words there is a unique member of the + + + align:start position:0% +words there is a unique member of the +family y = C1 E X Plus C2 e 3x that + + align:start position:0% +family y = C1 E X Plus C2 e 3x that + + + align:start position:0% +family y = C1 E X Plus C2 e 3x that +passes through the point x0 y0 with a + + align:start position:0% +passes through the point x0 y0 with a + + + align:start position:0% +passes through the point x0 y0 with a +given slope z0 that's what we prove over + + align:start position:0% +given slope z0 that's what we prove over + + + align:start position:0% +given slope z0 that's what we prove over +here the only question that comes up is + + align:start position:0% +here the only question that comes up is + + + align:start position:0% +here the only question that comes up is +is that we have now shown what that at + + align:start position:0% +is that we have now shown what that at + + + align:start position:0% +is that we have now shown what that at +every point in space there is one + + align:start position:0% +every point in space there is one + + + align:start position:0% +every point in space there is one +solution from this family that passes + + align:start position:0% +solution from this family that passes + + + align:start position:0% +solution from this family that passes +through the given point with any given + + align:start position:0% +through the given point with any given + + + align:start position:0% +through the given point with any given +slope that you want it to have the + + align:start position:0% +slope that you want it to have the + + + align:start position:0% +slope that you want it to have the +question is that before we can call this + + align:start position:0% +question is that before we can call this + + + align:start position:0% +question is that before we can call this +the general solution we have to be sure + + align:start position:0% +the general solution we have to be sure + + + align:start position:0% +the general solution we have to be sure +that there are no other solutions to the + + align:start position:0% +that there are no other solutions to the + + + align:start position:0% +that there are no other solutions to the +equation Y Prime minus 4 y Prime + 3 yal + + align:start position:0% +equation Y Prime minus 4 y Prime + 3 yal + + + align:start position:0% +equation Y Prime minus 4 y Prime + 3 yal +0 in other words the question is are are + + align:start position:0% +0 in other words the question is are are + + + align:start position:0% +0 in other words the question is are are +there other types of solutions solutions + + align:start position:0% +there other types of solutions solutions + + + align:start position:0% +there other types of solutions solutions +that aren't of the form e to the x or E + + align:start position:0% +that aren't of the form e to the x or E + + + align:start position:0% +that aren't of the form e to the x or E +to 3x or linear combinations thereof and + + align:start position:0% +to 3x or linear combinations thereof and + + + align:start position:0% +to 3x or linear combinations thereof and +the crucial theorem is this suppose we + + align:start position:0% +the crucial theorem is this suppose we + + + align:start position:0% +the crucial theorem is this suppose we +can write our second order equation in + + align:start position:0% +can write our second order equation in + + + align:start position:0% +can write our second order equation in +the form y Prime is some function of X Y + + align:start position:0% +the form y Prime is some function of X Y + + + align:start position:0% +the form y Prime is some function of X Y +and Y Prime and notice how analogous + + align:start position:0% +and Y Prime and notice how analogous + + + align:start position:0% +and Y Prime and notice how analogous +this is to the key theorem of our last + + align:start position:0% +this is to the key theorem of our last + + + align:start position:0% +this is to the key theorem of our last +lecture suppose when we treat x f as a + + align:start position:0% +lecture suppose when we treat x f as a + + + align:start position:0% +lecture suppose when we treat x f as a +function of the three independent + + align:start position:0% +function of the three independent + + + align:start position:0% +function of the three independent +variables X Y and Z it turns out that f + + align:start position:0% +variables X Y and Z it turns out that f + + + align:start position:0% +variables X Y and Z it turns out that f +f suby f subz are all continuous in some + + align:start position:0% +f suby f subz are all continuous in some + + + align:start position:0% +f suby f subz are all continuous in some +region R then the amazing result is that + + align:start position:0% +region R then the amazing result is that + + + align:start position:0% +region R then the amazing result is that +for each triplet x0 y0 z0 in R see R is + + align:start position:0% +for each triplet x0 y0 z0 in R see R is + + + align:start position:0% +for each triplet x0 y0 z0 in R see R is +three-dimensional here because f is + + align:start position:0% +three-dimensional here because f is + + + align:start position:0% +three-dimensional here because f is +defined on three space there is a unique + + align:start position:0% +defined on three space there is a unique + + + align:start position:0% +defined on three space there is a unique +solution curve which passes through the + + align:start position:0% +solution curve which passes through the + + + align:start position:0% +solution curve which passes through the +point x0 y0 with slope equal to z0 again + + align:start position:0% +point x0 y0 with slope equal to z0 again + + + align:start position:0% +point x0 y0 with slope equal to z0 again +notice here the coding system we are not + + align:start position:0% +notice here the coding system we are not + + + align:start position:0% +notice here the coding system we are not +talking about a solution passing through + + align:start position:0% +talking about a solution passing through + + + align:start position:0% +talking about a solution passing through +x0 y0 z0 the solution curve is in the + + align:start position:0% +x0 y0 z0 the solution curve is in the + + + align:start position:0% +x0 y0 z0 the solution curve is in the +plane see dydx is a slope of a curve in + + align:start position:0% +plane see dydx is a slope of a curve in + + + align:start position:0% +plane see dydx is a slope of a curve in +the plane we have one independent + + align:start position:0% +the plane we have one independent + + + align:start position:0% +the plane we have one independent +variable what we're saying is what that + + align:start position:0% +variable what we're saying is what that + + + align:start position:0% +variable what we're saying is what that +there is a unique solution that passes + + align:start position:0% +there is a unique solution that passes + + + align:start position:0% +there is a unique solution that passes +through the point x0 y0 with slope equal + + align:start position:0% +through the point x0 y0 with slope equal + + + align:start position:0% +through the point x0 y0 with slope equal +to z0 under those conditions the + + align:start position:0% +to z0 under those conditions the + + + align:start position:0% +to z0 under those conditions the +solution will be unique well let's + + align:start position:0% +solution will be unique well let's + + + align:start position:0% +solution will be unique well let's +accept the truth of this theorem and + + align:start position:0% +accept the truth of this theorem and + + + align:start position:0% +accept the truth of this theorem and +apply it to a linear differential + + align:start position:0% +apply it to a linear differential + + + align:start position:0% +apply it to a linear differential +equation given the most General linear + + align:start position:0% +equation given the most General linear + + + align:start position:0% +equation given the most General linear +differential equation to put it into the + + align:start position:0% +differential equation to put it into the + + + align:start position:0% +differential equation to put it into the +form of the crucial theorem I transpose + + align:start position:0% +form of the crucial theorem I transpose + + + align:start position:0% +form of the crucial theorem I transpose +everything but y Prime onto the right + + align:start position:0% +everything but y Prime onto the right + + + align:start position:0% +everything but y Prime onto the right +hand side of the equation I get y Prime + + align:start position:0% +hand side of the equation I get y Prime + + + align:start position:0% +hand side of the equation I get y Prime +f ofx - P of x y primeus q ofx y + + align:start position:0% +f ofx - P of x y primeus q ofx y + + + align:start position:0% +f ofx - P of x y primeus q ofx y +therefore my capital F of XYZ is obtain + + align:start position:0% +therefore my capital F of XYZ is obtain + + + align:start position:0% +therefore my capital F of XYZ is obtain +simply by replacing y Prime by Z in here + + align:start position:0% +simply by replacing y Prime by Z in here + + + align:start position:0% +simply by replacing y Prime by Z in here +see I simply replace y Prime by Z like I + + align:start position:0% +see I simply replace y Prime by Z like I + + + align:start position:0% +see I simply replace y Prime by Z like I +did over here I wind up with what y + + align:start position:0% +did over here I wind up with what y + + + align:start position:0% +did over here I wind up with what y +capital F of XYZ is little F ofx minus + + align:start position:0% +capital F of XYZ is little F ofx minus + + + align:start position:0% +capital F of XYZ is little F ofx minus +pz minus qy well look at this is this is + + align:start position:0% +pz minus qy well look at this is this is + + + align:start position:0% +pz minus qy well look at this is this is +certainly a continuous function as soon + + align:start position:0% +certainly a continuous function as soon + + + align:start position:0% +certainly a continuous function as soon +as FP and Q are continuous the partial + + align:start position:0% +as FP and Q are continuous the partial + + + align:start position:0% +as FP and Q are continuous the partial +of capital F with respect to Y remember + + align:start position:0% +of capital F with respect to Y remember + + + align:start position:0% +of capital F with respect to Y remember +I'm treating X Y and Z as independent + + align:start position:0% +I'm treating X Y and Z as independent + + + align:start position:0% +I'm treating X Y and Z as independent +variables if I differentiate with + + align:start position:0% +variables if I differentiate with + + + align:start position:0% +variables if I differentiate with +respect to Y notice that this drops out + + align:start position:0% +respect to Y notice that this drops out + + + align:start position:0% +respect to Y notice that this drops out +the partial of capital F with respect to + + align:start position:0% +the partial of capital F with respect to + + + align:start position:0% +the partial of capital F with respect to +Y is just minus Q ofx the partial of + + align:start position:0% +Y is just minus Q ofx the partial of + + + align:start position:0% +Y is just minus Q ofx the partial of +capital F with respect to Z is just + + align:start position:0% +capital F with respect to Z is just + + + align:start position:0% +capital F with respect to Z is just +minus P of X consequently if little f p + + align:start position:0% +minus P of X consequently if little f p + + + align:start position:0% +minus P of X consequently if little f p +and Q are all continuous functions of X + + align:start position:0% +and Q are all continuous functions of X + + + align:start position:0% +and Q are all continuous functions of X +automatically capital F capital F suby + + align:start position:0% +automatically capital F capital F suby + + + align:start position:0% +automatically capital F capital F suby +capital F subz will also be Contin + + align:start position:0% +capital F subz will also be Contin + + + align:start position:0% +capital F subz will also be Contin +functions consequently according to that + + align:start position:0% +functions consequently according to that + + + align:start position:0% +functions consequently according to that +crucial theorem any solution that I find + + align:start position:0% +crucial theorem any solution that I find + + + align:start position:0% +crucial theorem any solution that I find +will be a unique solution and even more + + align:start position:0% +will be a unique solution and even more + + + align:start position:0% +will be a unique solution and even more +to the point even if I can't find the + + align:start position:0% +to the point even if I can't find the + + + align:start position:0% +to the point even if I can't find the +solution the theorem tells me that there + + align:start position:0% +solution the theorem tells me that there + + + align:start position:0% +solution the theorem tells me that there +is a unique solution well I think that + + align:start position:0% +is a unique solution well I think that + + + align:start position:0% +is a unique solution well I think that +the P's and the q's sort of get you a + + align:start position:0% +the P's and the q's sort of get you a + + + align:start position:0% +the P's and the q's sort of get you a +little bit messed up let's do a specific + + align:start position:0% +little bit messed up let's do a specific + + + align:start position:0% +little bit messed up let's do a specific +uh illustration of this again let's find + + align:start position:0% +uh illustration of this again let's find + + + align:start position:0% +uh illustration of this again let's find +now all solutions of the equation Y + + align:start position:0% +now all solutions of the equation Y + + + align:start position:0% +now all solutions of the equation Y +Prime - 4 y Prime + 3 y equal e 2x the + + align:start position:0% +Prime - 4 y Prime + 3 y equal e 2x the + + + align:start position:0% +Prime - 4 y Prime + 3 y equal e 2x the +same equation as before only the right + + align:start position:0% +same equation as before only the right + + + align:start position:0% +same equation as before only the right +hand side is e 2x rather than zero the + + align:start position:0% +hand side is e 2x rather than zero the + + + align:start position:0% +hand side is e 2x rather than zero the +key result is going to be this I already + + align:start position:0% +key result is going to be this I already + + + align:start position:0% +key result is going to be this I already +know how to solve this equation when the + + align:start position:0% +know how to solve this equation when the + + + align:start position:0% +know how to solve this equation when the +right hand side is zero remember one of + + align:start position:0% +right hand side is zero remember one of + + + align:start position:0% +right hand side is zero remember one of +my properties of linearity was that if I + + align:start position:0% +my properties of linearity was that if I + + + align:start position:0% +my properties of linearity was that if I +could find any solution of this equation + + align:start position:0% +could find any solution of this equation + + + align:start position:0% +could find any solution of this equation +then by adding onto it any solution of + + align:start position:0% +then by adding onto it any solution of + + + align:start position:0% +then by adding onto it any solution of +the equation where the right hand side + + align:start position:0% +the equation where the right hand side + + + align:start position:0% +the equation where the right hand side +is zero by the way when the right hand + + align:start position:0% +is zero by the way when the right hand + + + align:start position:0% +is zero by the way when the right hand +side is zero the equation is called uh + + align:start position:0% +side is zero the equation is called uh + + + align:start position:0% +side is zero the equation is called uh +homogeneous and I don't think that's too + + align:start position:0% +homogeneous and I don't think that's too + + + align:start position:0% +homogeneous and I don't think that's too +important other than to know the + + align:start position:0% +important other than to know the + + + align:start position:0% +important other than to know the +language when it's mentioned but this is + + align:start position:0% +language when it's mentioned but this is + + + align:start position:0% +language when it's mentioned but this is +called homogeneous if the right hand + + align:start position:0% +called homogeneous if the right hand + + + align:start position:0% +called homogeneous if the right hand +side is zero but what our key theorem + + align:start position:0% +side is zero but what our key theorem + + + align:start position:0% +side is zero but what our key theorem +says is look at we have solved this + + align:start position:0% +says is look at we have solved this + + + align:start position:0% +says is look at we have solved this +problem we have found the general + + align:start position:0% +problem we have found the general + + + align:start position:0% +problem we have found the general +solution when the right hand side is + + align:start position:0% +solution when the right hand side is + + + align:start position:0% +solution when the right hand side is +zero consequently if I could find just + + align:start position:0% +zero consequently if I could find just + + + align:start position:0% +zero consequently if I could find just +one solution of this equation by hook or + + align:start position:0% +one solution of this equation by hook or + + + align:start position:0% +one solution of this equation by hook or +by crook just steal one sneak one in if + + align:start position:0% +by crook just steal one sneak one in if + + + align:start position:0% +by crook just steal one sneak one in if +I can find one solution of that equation + + align:start position:0% +I can find one solution of that equation + + + align:start position:0% +I can find one solution of that equation +if I add that onto the General solution + + align:start position:0% +if I add that onto the General solution + + + align:start position:0% +if I add that onto the General solution +of the homogeneous equation that will be + + align:start position:0% +of the homogeneous equation that will be + + + align:start position:0% +of the homogeneous equation that will be +the general solution of this equation + + align:start position:0% +the general solution of this equation + + + align:start position:0% +the general solution of this equation +what does that mean let's see how we'll + + align:start position:0% +what does that mean let's see how we'll + + + align:start position:0% +what does that mean let's see how we'll +tackle this what I'm going to do is I + + align:start position:0% +tackle this what I'm going to do is I + + + align:start position:0% +tackle this what I'm going to do is I +look at this equation and here's how I + + align:start position:0% +look at this equation and here's how I + + + align:start position:0% +look at this equation and here's how I +get sneaky I say look at when I + + align:start position:0% +get sneaky I say look at when I + + + align:start position:0% +get sneaky I say look at when I +differentiate and I'm all through what I + + align:start position:0% +differentiate and I'm all through what I + + + align:start position:0% +differentiate and I'm all through what I +want to wind up with is e to 2x well the + + align:start position:0% +want to wind up with is e to 2x well the + + + align:start position:0% +want to wind up with is e to 2x well the +only function whose derivative gives you + + align:start position:0% +only function whose derivative gives you + + + align:start position:0% +only function whose derivative gives you +a factor of e to 2x more or less is some + + align:start position:0% +a factor of e to 2x more or less is some + + + align:start position:0% +a factor of e to 2x more or less is some +constant time e to 2x itself so I say to + + align:start position:0% +constant time e to 2x itself so I say to + + + align:start position:0% +constant time e to 2x itself so I say to +myself let me try for a solution in the + + align:start position:0% +myself let me try for a solution in the + + + align:start position:0% +myself let me try for a solution in the +form y equal some constant * e 2x see my + + align:start position:0% +form y equal some constant * e 2x see my + + + align:start position:0% +form y equal some constant * e 2x see my +tri solution will have this form well YT + + align:start position:0% +tri solution will have this form well YT + + + align:start position:0% +tri solution will have this form well YT +Prime would be this YT Prime would be + + align:start position:0% +Prime would be this YT Prime would be + + + align:start position:0% +Prime would be this YT Prime would be +this if I now substitute back into the + + align:start position:0% +this if I now substitute back into the + + + align:start position:0% +this if I now substitute back into the +original equation YT Prime - 4 YT Prime + + align:start position:0% +original equation YT Prime - 4 YT Prime + + + align:start position:0% +original equation YT Prime - 4 YT Prime ++ 3 YT must be identically equal to e to + + align:start position:0% ++ 3 YT must be identically equal to e to + + + align:start position:0% ++ 3 YT must be identically equal to e to +X that leads to the fact that minus a e + + align:start position:0% +X that leads to the fact that minus a e + + + align:start position:0% +X that leads to the fact that minus a e +2X must be the same as e to 2X and that + + align:start position:0% +2X must be the same as e to 2X and that + + + align:start position:0% +2X must be the same as e to 2X and that +tells me that if there is a solution a + + align:start position:0% +tells me that if there is a solution a + + + align:start position:0% +tells me that if there is a solution a +had better be minus one you see if x is + + align:start position:0% +had better be minus one you see if x is + + + align:start position:0% +had better be minus one you see if x is +Zer here this says - AAL 1 a quick check + + align:start position:0% +Zer here this says - AAL 1 a quick check + + + align:start position:0% +Zer here this says - AAL 1 a quick check +will show that Min - e 2x is a solution + + align:start position:0% +will show that Min - e 2x is a solution + + + align:start position:0% +will show that Min - e 2x is a solution +of the equation so a particular solution + + align:start position:0% +of the equation so a particular solution + + + align:start position:0% +of the equation so a particular solution +of this equation is minus E 2x I found + + align:start position:0% +of this equation is minus E 2x I found + + + align:start position:0% +of this equation is minus E 2x I found +one solution now here's the power of all + + align:start position:0% +one solution now here's the power of all + + + align:start position:0% +one solution now here's the power of all +this Theory with this one solution I now + + align:start position:0% +this Theory with this one solution I now + + + align:start position:0% +this Theory with this one solution I now +go back to the homogeneous equation + + align:start position:0% +go back to the homogeneous equation + + + align:start position:0% +go back to the homogeneous equation +which had as its General solution C1 e + + align:start position:0% +which had as its General solution C1 e + + + align:start position:0% +which had as its General solution C1 e +to X Plus C2 e to 3x I add these two + + align:start position:0% +to X Plus C2 e to 3x I add these two + + + align:start position:0% +to X Plus C2 e to 3x I add these two +together and that is the general + + align:start position:0% +together and that is the general + + + align:start position:0% +together and that is the general +solution that is the general solution of + + align:start position:0% +solution that is the general solution of + + + align:start position:0% +solution that is the general solution of +the equation that I started with by the + + align:start position:0% +the equation that I started with by the + + + align:start position:0% +the equation that I started with by the +way notice this as a check if this were + + align:start position:0% +way notice this as a check if this were + + + align:start position:0% +way notice this as a check if this were +the general solution I should be able to + + align:start position:0% +the general solution I should be able to + + + align:start position:0% +the general solution I should be able to +find unique values for C1 and C2 that + + align:start position:0% +find unique values for C1 and C2 that + + + align:start position:0% +find unique values for C1 and C2 that +allow me to make the curve a solution + + align:start position:0% +allow me to make the curve a solution + + + align:start position:0% +allow me to make the curve a solution +curve pass through x0 y0 with slope + + align:start position:0% +curve pass through x0 y0 with slope + + + align:start position:0% +curve pass through x0 y0 with slope +equal to0 0 notice that that would + + align:start position:0% +equal to0 0 notice that that would + + + align:start position:0% +equal to0 0 notice that that would +result in this system of equations and I + + align:start position:0% +result in this system of equations and I + + + align:start position:0% +result in this system of equations and I +hope that you notice that since x0 y0 + + align:start position:0% +hope that you notice that since x0 y0 + + + align:start position:0% +hope that you notice that since x0 y0 +and z0 are constants to determine + + align:start position:0% +and z0 are constants to determine + + + align:start position:0% +and z0 are constants to determine +whether C1 and C2 are uniquely + + align:start position:0% +whether C1 and C2 are uniquely + + + align:start position:0% +whether C1 and C2 are uniquely +determined or not hinges on the fact + + align:start position:0% +determined or not hinges on the fact + + + align:start position:0% +determined or not hinges on the fact +that the coefficient M Matrix the + + align:start position:0% +that the coefficient M Matrix the + + + align:start position:0% +that the coefficient M Matrix the +determinant of coefficients is still the + + align:start position:0% +determinant of coefficients is still the + + + align:start position:0% +determinant of coefficients is still the +same determinant of coefficients that I + + align:start position:0% +same determinant of coefficients that I + + + align:start position:0% +same determinant of coefficients that I +had in the homogeneous Case by the way + + align:start position:0% +had in the homogeneous Case by the way + + + align:start position:0% +had in the homogeneous Case by the way +let me just stress one more point that I + + align:start position:0% +let me just stress one more point that I + + + align:start position:0% +let me just stress one more point that I +forgot to mention over here + + align:start position:0% +forgot to mention over here + + + align:start position:0% +forgot to mention over here +when I wrote down this equation notice + + align:start position:0% +when I wrote down this equation notice + + + align:start position:0% +when I wrote down this equation notice +that for the fundamental theorem to be + + align:start position:0% +that for the fundamental theorem to be + + + align:start position:0% +that for the fundamental theorem to be +true all that we required was that PQ + + align:start position:0% +true all that we required was that PQ + + + align:start position:0% +true all that we required was that PQ +and little F be continuous notice that P + + align:start position:0% +and little F be continuous notice that P + + + align:start position:0% +and little F be continuous notice that P +in this problem is minus 4 q is 3 and F + + align:start position:0% +in this problem is minus 4 q is 3 and F + + + align:start position:0% +in this problem is minus 4 q is 3 and F +is e to 2x certainly the function f ofx + + align:start position:0% +is e to 2x certainly the function f ofx + + + align:start position:0% +is e to 2x certainly the function f ofx +the function which is identically minus + + align:start position:0% +the function which is identically minus + + + align:start position:0% +the function which is identically minus +4 the function which is identically + + align:start position:0% +4 the function which is identically + + + align:start position:0% +4 the function which is identically +three and the function which is e to 2x + + align:start position:0% +three and the function which is e to 2x + + + align:start position:0% +three and the function which is e to 2x +are all continuous functions so what + + align:start position:0% +are all continuous functions so what + + + align:start position:0% +are all continuous functions so what +that told me was that once I find one + + align:start position:0% +that told me was that once I find one + + + align:start position:0% +that told me was that once I find one +one family of solutions I found them all + + align:start position:0% +one family of solutions I found them all + + + align:start position:0% +one family of solutions I found them all +so in the linear case there is a general + + align:start position:0% +so in the linear case there is a general + + + align:start position:0% +so in the linear case there is a general +solution there are no singular Solutions + + align:start position:0% +solution there are no singular Solutions + + + align:start position:0% +solution there are no singular Solutions +in a problem of this type there can't be + + align:start position:0% +in a problem of this type there can't be + + + align:start position:0% +in a problem of this type there can't be +any mongle solutions because this + + align:start position:0% +any mongle solutions because this + + + align:start position:0% +any mongle solutions because this +particular equation meets the + + align:start position:0% +particular equation meets the + + + align:start position:0% +particular equation meets the +requirements of the crucial theorem at + + align:start position:0% +requirements of the crucial theorem at + + + align:start position:0% +requirements of the crucial theorem at +any rate the exercises will take care of + + align:start position:0% +any rate the exercises will take care of + + + align:start position:0% +any rate the exercises will take care of +this in giving you drill let me simply + + align:start position:0% +this in giving you drill let me simply + + + align:start position:0% +this in giving you drill let me simply +summarize what we've done today in terms + + align:start position:0% +summarize what we've done today in terms + + + align:start position:0% +summarize what we've done today in terms +of linear differential equations the + + align:start position:0% +of linear differential equations the + + + align:start position:0% +of linear differential equations the +summary is this let's suppose that we're + + align:start position:0% +summary is this let's suppose that we're + + + align:start position:0% +summary is this let's suppose that we're +given a general second order is what + + align:start position:0% +given a general second order is what + + + align:start position:0% +given a general second order is what +I've been dealing with but it's true for + + align:start position:0% +I've been dealing with but it's true for + + + align:start position:0% +I've been dealing with but it's true for +higher orders 2 linear equation of the + + align:start position:0% +higher orders 2 linear equation of the + + + align:start position:0% +higher orders 2 linear equation of the +form y Prime + py Prime + qy = f ofx + + align:start position:0% +form y Prime + py Prime + qy = f ofx + + + align:start position:0% +form y Prime + py Prime + qy = f ofx +where p and Q are arbitrary functions of + + align:start position:0% +where p and Q are arbitrary functions of + + + align:start position:0% +where p and Q are arbitrary functions of +X what I'm saying is to find the general + + align:start position:0% +X what I'm saying is to find the general + + + align:start position:0% +X what I'm saying is to find the general +solution of this equation and by The + + align:start position:0% +solution of this equation and by The + + + align:start position:0% +solution of this equation and by The +crucial theorem this General solution + + align:start position:0% +crucial theorem this General solution + + + align:start position:0% +crucial theorem this General solution +will exist if FP and Q are continuous + + align:start position:0% +will exist if FP and Q are continuous + + + align:start position:0% +will exist if FP and Q are continuous +first of all what I do is I find the + + align:start position:0% +first of all what I do is I find the + + + align:start position:0% +first of all what I do is I find the +general solution y subh of the + + align:start position:0% +general solution y subh of the + + + align:start position:0% +general solution y subh of the +homogeneous equation L of y equals 0 in + + align:start position:0% +homogeneous equation L of y equals 0 in + + + align:start position:0% +homogeneous equation L of y equals 0 in +other words I simply replace the right + + align:start position:0% +other words I simply replace the right + + + align:start position:0% +other words I simply replace the right +hand side of this equation by zero and + + align:start position:0% +hand side of this equation by zero and + + + align:start position:0% +hand side of this equation by zero and +find the general solution of this + + align:start position:0% +find the general solution of this + + + align:start position:0% +find the general solution of this +equation in terms of a theory what we're + + align:start position:0% +equation in terms of a theory what we're + + + align:start position:0% +equation in terms of a theory what we're +saying also is and this I'll say this as + + align:start position:0% +saying also is and this I'll say this as + + + align:start position:0% +saying also is and this I'll say this as +an aside if I can find two solutions of + + align:start position:0% +an aside if I can find two solutions of + + + align:start position:0% +an aside if I can find two solutions of +this equation which are not Scala + + align:start position:0% +this equation which are not Scala + + + align:start position:0% +this equation which are not Scala +multiples of one another in other words + + align:start position:0% +multiples of one another in other words + + + align:start position:0% +multiples of one another in other words +if I can find two functions U1 and U2 + + align:start position:0% +if I can find two functions U1 and U2 + + + align:start position:0% +if I can find two functions U1 and U2 +such that L of U1 and L of U2 are zero + + align:start position:0% +such that L of U1 and L of U2 are zero + + + align:start position:0% +such that L of U1 and L of U2 are zero +but that U2 is not a constant time U1 + + align:start position:0% +but that U2 is not a constant time U1 + + + align:start position:0% +but that U2 is not a constant time U1 +then that homogeneous solution in other + + align:start position:0% +then that homogeneous solution in other + + + align:start position:0% +then that homogeneous solution in other +words the solution of this equation will + + align:start position:0% +words the solution of this equation will + + + align:start position:0% +words the solution of this equation will +simply be C1 U1 plus C2 U2 see other + + align:start position:0% +simply be C1 U1 plus C2 U2 see other + + + align:start position:0% +simply be C1 U1 plus C2 U2 see other +words all linear combinations of these + + align:start position:0% +words all linear combinations of these + + + align:start position:0% +words all linear combinations of these +two and the proof of that is quite + + align:start position:0% +two and the proof of that is quite + + + align:start position:0% +two and the proof of that is quite +simple namely what we want is what given + + align:start position:0% +simple namely what we want is what given + + + align:start position:0% +simple namely what we want is what given +the point x0 y0 we want to be sure that + + align:start position:0% +the point x0 y0 we want to be sure that + + + align:start position:0% +the point x0 y0 we want to be sure that +we can determine C1 and C2 such that a + + align:start position:0% +we can determine C1 and C2 such that a + + + align:start position:0% +we can determine C1 and C2 such that a +curve passes through x0 y0 with slope z0 + + align:start position:0% +curve passes through x0 y0 with slope z0 + + + align:start position:0% +curve passes through x0 y0 with slope z0 +that means I must be able to do what I + + align:start position:0% +that means I must be able to do what I + + + align:start position:0% +that means I must be able to do what I +must be able to solve this pair of + + align:start position:0% +must be able to solve this pair of + + + align:start position:0% +must be able to solve this pair of +equations namely if I replace X by x0 + + align:start position:0% +equations namely if I replace X by x0 + + + align:start position:0% +equations namely if I replace X by x0 +and Y by y0 and if I differentiate the + + align:start position:0% +and Y by y0 and if I differentiate the + + + align:start position:0% +and Y by y0 and if I differentiate the +equation and then replace X by x0 and + + align:start position:0% +equation and then replace X by x0 and + + + align:start position:0% +equation and then replace X by x0 and +dydx by z0 because that's the derivative + + align:start position:0% +dydx by z0 because that's the derivative + + + align:start position:0% +dydx by z0 because that's the derivative +the slope I want at this point I again + + align:start position:0% +the slope I want at this point I again + + + align:start position:0% +the slope I want at this point I again +wind up with what two equations with two + + align:start position:0% +wind up with what two equations with two + + + align:start position:0% +wind up with what two equations with two +unknowns remember once I specify x0 y0 + + align:start position:0% +unknowns remember once I specify x0 y0 + + + align:start position:0% +unknowns remember once I specify x0 y0 +and z0 + + align:start position:0% +and z0 + + + align:start position:0% +and z0 +these are given constants C1 and C2 are + + align:start position:0% +these are given constants C1 and C2 are + + + align:start position:0% +these are given constants C1 and C2 are +my only variables to see whether there + + align:start position:0% +my only variables to see whether there + + + align:start position:0% +my only variables to see whether there +is a unique solution here it means that + + align:start position:0% +is a unique solution here it means that + + + align:start position:0% +is a unique solution here it means that +this determinant of coefficients must be + + align:start position:0% +this determinant of coefficients must be + + + align:start position:0% +this determinant of coefficients must be +unequal to zero the determinant of + + align:start position:0% +unequal to zero the determinant of + + + align:start position:0% +unequal to zero the determinant of +coefficients is just U1 U2 Prime minus + + align:start position:0% +coefficients is just U1 U2 Prime minus + + + align:start position:0% +coefficients is just U1 U2 Prime minus +U1 Prime U2 that must be une equal to + + align:start position:0% +U1 Prime U2 that must be une equal to + + + align:start position:0% +U1 Prime U2 that must be une equal to +zero this suggests the quotient rule + + align:start position:0% +zero this suggests the quotient rule + + + align:start position:0% +zero this suggests the quotient rule +again for this expression to be une + + align:start position:0% +again for this expression to be une + + + align:start position:0% +again for this expression to be une +equal to Z is the same as this / U1 2 to + + align:start position:0% +equal to Z is the same as this / U1 2 to + + + align:start position:0% +equal to Z is the same as this / U1 2 to +Beal to Z this expression here is not + + align:start position:0% +Beal to Z this expression here is not + + + align:start position:0% +Beal to Z this expression here is not +nothing more than a derivative of U2 / + + align:start position:0% +nothing more than a derivative of U2 / + + + align:start position:0% +nothing more than a derivative of U2 / +U1 with respect to X and for that to be + + align:start position:0% +U1 with respect to X and for that to be + + + align:start position:0% +U1 with respect to X and for that to be +unequal to zero simply says what that U2 + + align:start position:0% +unequal to zero simply says what that U2 + + + align:start position:0% +unequal to zero simply says what that U2 +over U1 is not a constant and that says + + align:start position:0% +over U1 is not a constant and that says + + + align:start position:0% +over U1 is not a constant and that says +that U2 is not a constant times U1 in + + align:start position:0% +that U2 is not a constant times U1 in + + + align:start position:0% +that U2 is not a constant times U1 in +other words this is just an aside to + + align:start position:0% +other words this is just an aside to + + + align:start position:0% +other words this is just an aside to +show you how you find the general + + align:start position:0% +show you how you find the general + + + align:start position:0% +show you how you find the general +solution of the homogeneous equation but + + align:start position:0% +solution of the homogeneous equation but + + + align:start position:0% +solution of the homogeneous equation but +the point is what first of all you find + + align:start position:0% +the point is what first of all you find + + + align:start position:0% +the point is what first of all you find +the general solution of the homogeneous + + align:start position:0% +the general solution of the homogeneous + + + align:start position:0% +the general solution of the homogeneous +equation meaning you take L of yals f + + align:start position:0% +equation meaning you take L of yals f + + + align:start position:0% +equation meaning you take L of yals f +ofx replace F ofx by zero and find the + + align:start position:0% +ofx replace F ofx by zero and find the + + + align:start position:0% +ofx replace F ofx by zero and find the +general solution of L of y equals z + + align:start position:0% +general solution of L of y equals z + + + align:start position:0% +general solution of L of y equals z +after you've done that you find any old + + align:start position:0% +after you've done that you find any old + + + align:start position:0% +after you've done that you find any old +solution y sub P of the given equation L + + align:start position:0% +solution y sub P of the given equation L + + + align:start position:0% +solution y sub P of the given equation L +of yals f ofx just one solution by hooka + + align:start position:0% +of yals f ofx just one solution by hooka + + + align:start position:0% +of yals f ofx just one solution by hooka +by crook then finally when you have the + + align:start position:0% +by crook then finally when you have the + + + align:start position:0% +by crook then finally when you have the +general solution of the reduced the + + align:start position:0% +general solution of the reduced the + + + align:start position:0% +general solution of the reduced the +homogeneous equation and the particular + + align:start position:0% +homogeneous equation and the particular + + + align:start position:0% +homogeneous equation and the particular +solution of this equation the general + + align:start position:0% +solution of this equation the general + + + align:start position:0% +solution of this equation the general +solution of this equation will just be + + align:start position:0% +solution of this equation will just be + + + align:start position:0% +solution of this equation will just be +the sum of these two all right and + + align:start position:0% +the sum of these two all right and + + + align:start position:0% +the sum of these two all right and +that's what we're going to be talking + + align:start position:0% +that's what we're going to be talking + + + align:start position:0% +that's what we're going to be talking +about in the next few lessons see what + + align:start position:0% +about in the next few lessons see what + + + align:start position:0% +about in the next few lessons see what +we're going to drill on is what this + + align:start position:0% +we're going to drill on is what this + + + align:start position:0% +we're going to drill on is what this +stuff means and I think you can now + + align:start position:0% +stuff means and I think you can now + + + align:start position:0% +stuff means and I think you can now +guess what the next lectures are going + + align:start position:0% +guess what the next lectures are going + + + align:start position:0% +guess what the next lectures are going +to be about after all since to find the + + align:start position:0% +to be about after all since to find the + + + align:start position:0% +to be about after all since to find the +general solution of the linear + + align:start position:0% +general solution of the linear + + + align:start position:0% +general solution of the linear +differential equation I need the general + + align:start position:0% +differential equation I need the general + + + align:start position:0% +differential equation I need the general +solution of the homogeneous equation and + + align:start position:0% +solution of the homogeneous equation and + + + align:start position:0% +solution of the homogeneous equation and +a particular solution of the original + + align:start position:0% +a particular solution of the original + + + align:start position:0% +a particular solution of the original +equation the two separate topics I now + + align:start position:0% +equation the two separate topics I now + + + align:start position:0% +equation the two separate topics I now +have to tackle are one how do I find the + + align:start position:0% +have to tackle are one how do I find the + + + align:start position:0% +have to tackle are one how do I find the +general solution of the reduced equation + + align:start position:0% +general solution of the reduced equation + + + align:start position:0% +general solution of the reduced equation +and two how do I find a particular + + align:start position:0% +and two how do I find a particular + + + align:start position:0% +and two how do I find a particular +solution of the original equation that + + align:start position:0% +solution of the original equation that + + + align:start position:0% +solution of the original equation that +by the way comes Under The Heading of + + align:start position:0% +by the way comes Under The Heading of + + + align:start position:0% +by the way comes Under The Heading of +cookbook again that's drill but this is + + align:start position:0% +cookbook again that's drill but this is + + + align:start position:0% +cookbook again that's drill but this is +the underlying Theory the underlying + + align:start position:0% +the underlying Theory the underlying + + + align:start position:0% +the underlying Theory the underlying +philosophy we will talk more about how + + align:start position:0% +philosophy we will talk more about how + + + align:start position:0% +philosophy we will talk more about how +to handle the techniques in our + + align:start position:0% +to handle the techniques in our + + + align:start position:0% +to handle the techniques in our +subsequent lectures at any rate then + + align:start position:0% +subsequent lectures at any rate then + + + align:start position:0% +subsequent lectures at any rate then +until next time + + align:start position:0% + + + + align:start position:0% + +goodbye funding for the publication of + + align:start position:0% +goodbye funding for the publication of + + + align:start position:0% +goodbye funding for the publication of +this video was provided by the Gabriella + + align:start position:0% +this video was provided by the Gabriella + + + align:start position:0% +this video was provided by the Gabriella +and Paul rosenbom + + align:start position:0% +and Paul rosenbom + + + align:start position:0% +and Paul rosenbom +foundation help ocw continue to provide + + align:start position:0% +foundation help ocw continue to provide + + + align:start position:0% +foundation help ocw continue to provide +free and open access to MIT courses by + + align:start position:0% +free and open access to MIT courses by + + + align:start position:0% +free and open access to MIT courses by +making a donation at ocw.mit.edu/donate \ No newline at end of file diff --git a/J2uMjEDsE6s.txt b/J2uMjEDsE6s.txt new file mode 100644 index 0000000000000000000000000000000000000000..69761caa1615efccaea15a8143727ccf62b4cff1 --- /dev/null +++ b/J2uMjEDsE6s.txt @@ -0,0 +1,2120 @@ +PROFESSOR: This class is talking +about two lectures, both about + +protein folding, fixed angled +chains, things like that. + +There's a few +questions about them. + +One is mostly about +these open problems, + +equilateral, equiangular, +obtuse 3D chains, + +fixed angle open problem +is, are they locked? + +So the question is about, +what about any subset + +of those combinations? + +So this originally comes +from an open problem + +I think posed in 1999, one of +the first 3D linkage papers, + +and it asked whether equilateral +universal joints can lock, + +and that's still open. + +For universal joints, +these two constraints + +don't make a lot of +sense because who + +cares if it's +initially equiangular. + +As soon as you move it, it +will no longer be equiangular. + +And obtuseness I don't +think matters too much, + +although it potentially could. + +So for that problem, equilateral +seems to be the core. + +For fixed angle, +though, we conjecture + +that fixed angle equilateral is +not enough from this example. + +It's still not +proved to be locked. + +I don't know if it's hard, +but it's probably tedious, + +so it hasn't been done. + +This was the crossed +legs example. + +All the edge lengths +are the same, + +and if you don't allow +the touching part, + +then all the angles +are also the same. + +So this is everything +except the obtuse property + +and it's probably locked, so +dropping obtuse is no good. + +The other things you could drop +are equilateral or equiangular. + +This is if you drop equiangular. + +Fixed angle equilateral is +not terribly constraining + +because you can +simulate a long bar + +by having a lot of +180 degree angles. + +This is obtuse and +it's equilateral + +but it's not +equiangular and it's + +locked for a trivial reason. + +So this is dropping equiangular. + +If I drop equilateral, +I can also + +just make a knitting +needles example. + +I take a really long link, and +this thing is basically string, + +so I don't really care. + +This connection can be done +with a lot of obtuse angles, + +and then have a +really long link. + +So dropping any of +the three constraints + +makes it easy to lock, so +for fixed angle chains, + +you need equilateral, +equiangular, and obtuse. + +All these things +together potentially mean + +you're not locked, +but we don't know. + +That's the open problem. + +Of course, we don't +necessarily need + +exactly equilateral +or equiangular. + +Hopefully, within some small min +to max ratio would be enough, + +but we don't know. + +Next question is, why did we +model the ribosome as a cone? + +That seems rather simple. + +Is this realistic? + +And partly, when I +taught the class in 2010, + +I didn't use any images I +couldn't get permission for. + +This year I'm more lax. + +We'll ask for forgiveness +instead of permission. + +This is a paper +from Science 2000. + +This is what the ribosome +actually looks like. + +There's many different +figures of it, + +but I particularly like this +one because it highlights + +a tunnel in the center +of the ribosome. + +And so the idea is this is a +machine for converting MRNA + +into your proteins, +and the idea is + +the protein comes through here. + +There's a little +bump in the tunnel. + +Some people conjecture this +is where the amino acid gets + +attached, and then +it feeds through here + +and starts spitting out. + +And as I said, there's +barely enough room + +here for an alpha helix, so +probably not too much folding + +happens inside and the folding +should just happen over here. + +And the observation is if +you have a reasonable size + +protein that's only going +to be about this big, + +then there's this big, +flat wall at the exit, + +so you have a plane +there and this half space + +is more or less a big obstacle. + +It's the alpha cone model +where alpha is 180, I think, + +if alpha is the half angle. + +So it's not really a cone. + +It's a cone that's been opened +up all the way to a plane, + +but that's one of the situations +that's handled by the theorems + +that we talked about. + +So that's why the cone model. + +We generalize to +cones just because it + +works for general +cones, but the real one + +is a sort of flat cone. + +That's where that comes from. + +I think actually we proved the +theorem before we knew this, + +but then we looked it +up and it was true. + +And the last question +is about the lecture 21, + +which some of you may not have +watched because it's optional, + +but there's this model +called the HP model + +for protein folding. + +It's a model of +protein energy and it + +says you have a chain +of H and P nodes, + +and basically, the H nodes +are attracted to each other + +and the P nodes don't care. + +And the model is that the H +nodes are hydrophobic so they + +want to be next to each other +so they're not next to water, + +which is surrounding +the whole molecule, + +and the P nodes don't care, +or they're hydrophilic. + +And it's known that if +you have an HP string + +and you want to find the optimal +folding into a 2D or a 3D + +structure, that's NP-hard, +which is kind of weird + +because somehow +nature does it, maybe + +because it found the easy +instances by evolution, + +or maybe there's +something we're missing. + +This model doesn't +capture reality. + +We don't know. + +But it captures part of reality, +as least as we observe it. + +Unfortunately, these +hardness proofs + +are a little too +complicated to cover here, + +but I can at least answer +what are they reducing from. + +There's two proofs. + +I guess they were basically the +same time, I think around 2001. + +The first one here +is in 3D, and these + +are by two MIT professors. + +There's this big construction +but the reduction + +is from bin packing. + +So you have a bunch +of fixed size bins + +and you have a bunch of +items of varying sizes + +and you just want +to fit them all + +in using the fewest +bins possible. + +And the rough idea of the +construction of this one, this + +is how an individual +number is represented. + +The rough idea is you +have this big cube. + +You fill the sides +with stuff to protect + +from the outside boundary. + +The insides are just +used for connections, + +and then the front face +here is this stuff. + +You construct +these bins, and you + +construct numbers which +have to fit inside the bins. + +That's the rough idea. + +The details are complicated. + +The 2D proof by +several people is + +from Hamiltonicity in +maximum degree-4 graphs. + +So you have a graph +for every vertex that + +has at most four incident edges. + +You want to find a +Hamiltonian cycle, I think. + +It's much harder to see +this picture, I would say. + +There's no one diagram +that summarizes it. + +This is roughly +the construction, + +which is quite complicated, +and I'll just leave it at that. + +That's what they're +reduced from. + +I think an interesting +open problem + +would be to find a simple or +cleaner proof of these results. + +Now that it's known +that they're hard, + +it's probably easy +or hardness proofs. + +There's also some open +questions from lecture, + +like is it APX hard? + +Is it approximable to a 1 +plus epsilon factor or 1 minus + +epsilon factor for any +epsilon or is there + +some limit to approximability? + +We saw a nice approximation +4/3 whatever, 3/4 whatever, + +but can you do better? + +Still open. + +So that was the questions, +and then this is a question + +that you usually ask +in every lecture. + +You didn't actually +ask it on this one, + +but I copied and pasted. + +So there's some +interesting progress + +from this class two years ago, +and I think in the open problem + +session initially, probably +also a class project + +related to this part. + +So this is back in lecture 20. + +We had this proof, +which is kind of fun, + +that flattening a +fixed angle chain, + +deciding whether there +was a flat folded state, + +is weakly NP hard, +weakly meaning + +it depended a lot on what +these numbers look like + +and it was a reduction +from partitions. + +You had to split up the +numbers into two equal parts, + +and if you did, then this +key would fit in the slot + +and you're OK. + +If you didn't, the key would +collide with something here. + +So this means the +problem is hard + +if your edge lengths +are vastly different. + +They would have to differ +by a ratio of exponential + +in the number of edges for +this to really be hard. + +So a natural question is, +well, what if all the lengths + +are equal, equilateral chains? + +Turns out that is still hard, +and this is a paper just + +published last year with +Sarah Eisenstadt, who + +took the class then. + +And there's a bunch +of results here. + +All of these are NP hardness +results, strong NP hardness, + +so it doesn't depend +on the numbers. + +We've got flattening results. + +There's also min flat +span and max flat span. + +Once you have that +flattening is hard, + +these are pretty +easy to show hard, + +so I won't talk +about them so much. + +But basically, we consider +different ranges of angles + +and what you might allow. + +In some cases, we can get +perfect equilateral chains. + +In some cases, they have to +range between, say, 1 and 2 + +in length. + +A natural question +is obtuse angles. + +We don't quite know that. + +The best we have is 60 degrees +minus epsilon and larger. + +This is nice for +orthogonal chains, + +but it's not for +chains, it's for trees. + +So still some open questions +here, but lots of hardness + +results. + +I thought I'd show you roughly +what the hardness proofs look + +like because +they're kind of fun. + +They all follow this +kind of structure. + +This is a gadget, and +it's a fixed angle chain. + +Here I'm going to show +everything with 90 degrees + +because it's easier +to think about. + +And it's kind of like-- +I'm thinking plunger, + +but it's something like that. + +You can decide which +parts get pushed in + +and which parts get popped out, +and this L shape can basically + +shift left and right to +three different places + +if I did it right-- this +one, this one, and this one. + +So that's a useful construction, +as you might imagine, + +and the idea is you take that +and you add on these guys. + +So I've got another kind +of plungey thing like this, + +and this guy can move left +and right to various extents. + +That's not very intuitive. + +So then this connects +to these little guys, + +and these can just +flip up or down + +if it's a flat embedding +of a fixed angle chain. + +And so the idea is you have +three of these pokey elements + +and they can attach. + +They bump into these +different things. + +And if it's up, +then this can be up, + +but when they're down-- like +this guy is currently down, + +but it could be pushed +up-- then this guy + +must be flipped down like that. + +That's the rough idea of how +these parts fit together. + +And so then this is how you end +up building some kind of three + +sat problem. + +So you have some variables. + +They can either +be true or false. + +And the idea is that the +true guys are on the top, + +the bottom guys +are on the bottom, + +and there's some complicated +interaction between them + +to make sure that they can't +both be true and false. + +Basically, you want +these things to point + +in whenever possible because +then these guys can go down. + +Otherwise, you would collide. + +And if this guy's in, +the corresponding guys + +in the bottom must +be down, and that's + +enforced by this long +thing, which is either + +completely down +or completely up. + +So when it's completely +down, these guys + +all have to be +down, which is going + +to be a problem down below +if things aren't satisfied. + +When it's up, all of these +guys would have to be up. + +Some of them could be +up if you feel like it, + +but really, you'd +probably put them + +all down whenever you +can because then you + +can take these guys +and stick them down. + +So this is how +you set variables, + +and then the other +things I showed + +were clauses, essentially. + +At least one of those +pins had to be pushed down + +and you don't know which one, +and that's the hard part. + +Rough sketch of how +this proof looks. + +One thing is here, +for this to work, + +these edges can't be spinnable. + +When I go here, I must +immediately go back down. + +I can't flip it. + +So these are rigid edges. + +That's not really +the original problem, + +but you can simulate +rigid edges, + +and this is where +the angles get small. + +You can simulate rigid edges +with a very sharp zigzag + +because if you ever +flipped one of these, + +it would collide with +the previous edge. + +So for sufficiently +sharp angles, + +you can force parts to stay +straight in this funny way, + +which is not great, but +it's one way to force it. + +We can also do it with trees +or various other techniques, + +but that's how the proof looks. + +So that is flattening fixed +angle chains, strongly NP hard. + +We go next to one +more topic for fun. + +This is the topic of flips. + +I guess I have an +image for this. + +This is a problem +posed by Paul Erdos, + +I think when he was a student. + +He was a very famous +mathematician. + +1935, he asked this question. + +This is the whole question +as originally written. + +You have a polygon and you take +the convex hull of the polygon, + +and you take these regions +which are in the convex hull + +but outside the polygon. + +We call those pockets. + +And you imagine +flipping those outside, + +reflecting through +that supporting line, + +that tangent on the outside, +so then you get this polygon. + +Here you get two pockets. + +Maybe you flip both of them, and +then you get a convex polygon. + +Now you have no pockets, +and so you're done. + +And the question is as posed. + +Prove that after a finite +number of such steps, + +the polygon would become convex. + +So you might call this +a conjecture by Erdos + +that it is finite. + +He'd never published a proof. + +There's one issue with +the problem as stated. + +You can't actually +flip both pockets + +at once if you want +to avoid collisions. + +The relation to +linkages is we imagine + +these flips could actually +happen by a rotation, + +but you could also +just imagine them + +as reflecting instantaneously. + +There's this issue. + +If you flip two +pockets at once, you + +might have collisions +afterwards. + +The way this problem has been +interpreted by most people + +is don't flip them all at once. + +Just flip them one +at a time, and then + +you guarantee, because +this is a supporting line, + +a tangent line, of +the convex hull, + +when you flip one pocket out, +it will go to the other side + +so it can't intersect +the rest of the polygon. + +So you would avoid collision +if you do one flip at a time. + +Now, this was observed, I +guess, a few years later + +by Bela de Sz. + +Nagy, and he also +published the first proof. + +Before we get there, +a weird property + +and why you might worry about +this being finite or infinite + +is if you take +this quadrilateral + +and make this very narrow, +this edge very small + +relative to the +horizontal edge, then + +you can require arbitrarily +many flips to convexify. + +Even for n equals 4, you +could require a million flips. + +So definitely there's +some dependence + +on the ratio between the longest +length and the smallest length, + +though in open +problem, what we still + +don't know is whether you +can bound the number of flips + +in terms of n and that ratio. + +Is it pseudo-polynomial? + +Who knows? + +So it turns out +it's always finite, + +and there have been many proofs +over the years of this result. + +It's kind of been +rediscovered many times. + +Nagy solved it originally +in 1939, and he cited Erdos. + +These two guys +didn't cite anyone, + +so they may have come up with +the problem independently. + +This paper, these are +two Russian proofs. + +Then this paper cited-- +they knew about everything. + +They cited all of them. + +They cited Reshetnyak. + +I don't think they necessarily +knew about Yusupov. + +Independently, Kaluza +posed the problem in 1981 + +and Wegner solved it, and +then to finally clean it up, + +Grunbaum, who we saw +from un-un-unfoldable, + +knew about everything. + +Presumably, this is everything. + +Of course, we might +have missed one. + +But he knew all the above, +came up with his own proof. + +And then Godfried +Touissant, father + +of computational geometry, +one of them, knew about these + +and came up with yet +another, simpler proof. + +So the story of +this is kind of fun. + +When I taught this class for +the very first time, 2003 or so, + +I thought, OK, cool. + +This is a classic theorem. + +Everyone should know it. + +So I thought I'd cover the +latest proof that's presumably + +the best, so I covered +Godfried's proof. + +I was a little unhappy with +it, but I finished writing down + +the proof, and then one of +the students raised their hand + +and asked, is that really right? + +Can you do that in step two? + +And the answer was +no, you can't do that. + +It basically skipped a step. + +And so I thought, oh gee. + +And so I corresponded +with O'Rourke and Godfried + +that weekend and was like, +is something missing here? + +Maybe we should go back to +some of the other proofs + +because we've got +lots to choose from. + +So we went to the original, +which is a very short proof. + +It's only one page long, +maybe one and a half pages. + +And so this is fun. + +This is 1939, the way +mathematics used to be done. + +And it's funny because +Grunbaum's proof was based + +on Nagy's proof and +Toussaint's proof + +was based on Grunbaum's +proof, so in the end, + +these proofs were very similar. + +In fact, they differed +exactly in the one step, + +which was kind of omitted here. + +So I thought, OK great. + +Here we have a fill-in +on how to do it. + +And so the next class, I +went up and I presented it. + +I was really happy. + +Isn't this cool, +1939 mathematics? + +It's really awesome, +and it's one line + +that filled in this step. + +The same student raises +his hand and is like, + +I don't think that's true. + +So now the step was filled +in but it was wrong. + +So it turns out actually +most of these proofs + +are wrong, but not all +of them, fortunately, + +so the theorem is still true. + +So that one was wrong, this one +was wrong, this one was wrong, + +this one skipped a +step that was key, + +this one essentially also +skipped the step that was key. + +So in the end, there's two +correct proofs, Reshetnyak + +and Bing and Kazarinoff, +which was surprising. + +So I thought I'd show you one +of the errors in the Nagy proof. + +There's one other +interesting feature here, + +which is, why wasn't this +discovered until our class? + +The student was Blaise Gassand, +and so then we wrote a paper + +about it and we have our +own proof, of course. + +Now, some people +may have realized + +there was an error in +some of the proofs. + +Bing and Kazarinoff, one of +the correct proofs, a very nice + +one, wrote-- here's the +original Russian sentence. + +The English translation +is, "the proof + +of this theorem given +by Nagy is incorrect," + +which leaves something +to be desired. + +And Grunbaum, who +can read Russian-- + +we had to get them +translated-- mentioned this. + +So he noticed that point. "They +remarked that Nagy's proof is + +invalid but there's no +basis for this claim." + +Then it remained undiscovered +until 2005 or something. + +Kind of funny. + +Good thing there's so many +proofs to choose from. + +So this is Nagy's +original proof. + +You can see the example +where flipping two pockets + +simultaneously +causes a crossing. + +Don't read the whole +thing, obviously, + +but there's one +sentence here which is, + +if you take a polygon, call +it p0, and you flip a pocket + +and you get p1, and you flip +a pocket and you get p2, + +and you take the convex +hull of p and you get c0, + +and you take the convex hull +of p1 and you get c1, p2, + +you get c2. + +And then you interleave +these polygons + +so that the polygon is a convex +hull, next polygon is a convex + +hull, because you're +always flipping out, + +each of these polygons obviously +contains the foregoing ones. + +And so that seemed really +nice and we thought, + +oh, this is so elegant. + +They used this to prove that +the limit of the p's is convex + +because the limit +of the p's then + +would be the limit of the c's +because it was interleaving. + +But it's not true +that these things + +contain the previous ones +because if you have two pockets + +and you flip one of +them, it's this one + +pocket versus multiple +pockets issue. + +If you flip one of +them, that will not + +contain the convex +hull of the original + +because you haven't +flipped them all. + +If you flipped all the +pockets, than you would contain + +the convex hull of +the original, but that + +would end up arguing +that some flip + +sequences work, not all of them. + +So this is annoying, +and I think this + +is where I run out of slides. + +But we have some time, so I can +give you a sketch of the proof. + +This is the Bing and Kazarinoff +proof or our version of it. + +Give you an idea +of how this works. + +It's an easy proof, it's just +easy also to get it wrong + +or to skip one of the steps. + +I will just do a proof +by picture, I think. + +So suppose you have a +polygon on the plane, + +and let's say you flip a pocket. + +So this would look +something like that. + +A little hard to +do a reflection. + +So this is the +reflective polygon, + +and if we look at each of +the vertices over here, + +these guys don't move, +these guys moved over here, + +reflecting through that line. + +Observation one. + +If I take some point x +interior to the polygon, + +then these points that move +get farther away from x. + +Why? + +Because if you look +at this line here, + +let's say you look at a +vertex and where it goes. + +This line is the Voronoi +diagram of those two points. + +This is the perpendicular +bisector of this and this. + +That's the meaning +of reflection. + +So that means everything +to the left of the line + +here is closer to this +point than that point. + +Everything to the +right of the line + +is closer to this +point than that point. + +Now x, which is +interior to the polygon, + +must be to the left of the +line because the whole polygon + +is to the left of the line. + +So distance from x to +this vertex increases. + +I mean, x will remain +inside because as you flip, + +you only get bigger. + +So if I take a point x +and I look at the distance + +to some vertex, it can only +monotonically increase. + +It also can't get +arbitrarily large + +because the maximum +it could possibly be + +is half the perimeter +of the polygon. + +The perimeter of the +polygon is preserved + +so it can only stretch so far. + +So if you look at this distance, +it's monotonically increasing + +and it's bounded because +it can never get bigger + +than the perimeter +of the polygon. + +Therefore, it has a limit. + +That distance has +a limit because + +monotone bounded sequences +always have a unique limit. + +So cool. + +Distance from x to some +vertex has a limit. + +Well, I'm going to do this for +three different points, x, that + +lie on some non-degenerate +triangle, so not all on a line. + +That means the three +distances from these points + +to this vertex all +converge to some limit. + +And therefore, that +point converges + +to a limit, namely the +intersection of those three + +circles centered +at those points. + +So this proves that +the polygon has + +a limit because every +vertex has a limiting point. + +Cool. + +Now the tricky part is to +argue that limit is convex, + +and this is where +everyone had an issue. + +The first thing we argue is that +the angles converge to a limit. + +This is kind of a +technicality because we + +know the points +converge to a limit, + +so surely the angle does. + +The only issue is, well, +if all the points converge + +to the same point, then the +angle would not have a limit, + +but that's easy to +argue can't happen + +because these edge +links are preserved. + +So I will just skip that one. + +It follows from some +of the things we said. + +Now we get to the fun part. + +This polygon has a limit. + +The angles have limits. + +So I want to look at +the limiting angles. + +I want to in particular +look at the vertices that + +move because if you flip an +infinite number of times, that + +means some vertex must move +an infinite number of times, + +because every time you +flip, somebody moves. + +These guys are +considered not moving + +even though they're kind +of involved in the flip. + +So if you look at the moved +guys, what is their angle? + +So before, there +was some angle here, + +and afterwards, the interior +angle is the reverse. + +If this was reflex +before, it's convex now. + +If there were a convex +angle over here like this, + +it would become +reflex over here. + +You alternate between +being less than 180 + +and greater than 180 +every time you move. + +So if you have a vertex that is +moving infinitely many times, + +its angle must alternate +between less than 180 convex + +and greater than 180 reflex +infinitely many times. + +If that happens and you +have a unique limit angle, + +your limit angle must be 180. + +That's interesting. + +If our vertex moves +infinitely many times, + +then its limit angle +equals 180, must be flat. + +Very close to a +contradiction at this point. + +These guys are going to +end up looking like this. + +Well, let's look +at the other guys. + +So we have some limit polygon. + +In the limit polygon, there +are some flat vertices, + +but there must also be +some non-flat vertices. + +You can't just go straight +and hope to close a cycle. + +So there's maybe some +convex ones like this. + +There may be some reflex ones. + +At some point, +these vertices must + +stop moving because everyone +who moves infinitely many times + +has a limit angle flat. + +So anybody who is-- +we call it "pointed" + +here, although it's a little +different from pointed pseudo + +triangulations. + +Anyone who's not +a flat angle must + +stop moving after finite time. + +So let's go to that time +when all of these guys + +have stopped moving. + +So your limit +polygon is something. + +We don't know whether +it's convex or whatever. + +It could have many flat angles. + +It's got to have at +least one of them + +if we assume there's +something infinite here. + +This is the limit polygon. + +Now, at finite time, +we know that these guys + +have stopped moving, meaning +we're done with those guys. + +I've drawn the limit here, but +also the finite thing, which + +must be on the inside, right? + +This must be +something like this. + +Somehow it's going to flip and +reach the infinitely many times + +and reach this in the limit. + +Hm. + +That looks weird. + +So the way to argue +this in the clean way + +is if you look at the +convex hull of the limit, + +let's say, convex hull +of the limit is this. + +And look at the convex +hull of this finite time + +when the squared vertices +have stopped moving. + +Convex hull will +be-- well, it's got + +to be at least this because +these guys are already there. + +The convex hull is defined +by the square points. + +You don't care about +the flat vertices. + +That won't affect +the convex hull. + +So that means the convex +hull equals the limit convex + +hull at this finite time. + +Now you're about to +do another flip, which + +means you're going to +go outside that convex + +hull and contradiction. + +Is that clear? + +Maybe go through that +part one more time. + +After finite time, when all +of the non-flat vertices + +have stopped moving, we have +reached the final convex hull. + +That means you can't do any more +flips because every flip makes + +the convex hull +bigger, so you actually + +had to stop at that time. + +That's kind of a fun proof. + +The key is really this +part, that if a vertex flips + +infinitely many times, then +that limit angle must be flat, + +and so they really don't +participate in the convex hull. + +This is the Bing and +Kazarinoff key idea. + +AUDIENCE: Two questions. + +Does anyone do this for 3D? + +PROFESSOR: 3D is a good. + +People have tried to +define flips for 3D, + +and I think there's never really +been a successful definition. + +AUDIENCE: [INAUDIBLE]? + +PROFESSOR: Yeah, and +exactly how to flip it. + +I mean, you can define +pocket in the same way, + +but then the boundary +won't be a single plane. + +It'll be some convex +cap, and so flipping, you + +can't really just reflect. + +It's kind of annoying. + +AUDIENCE: The +other question was, + +you have a sequence +of simple operations + +that takes you from +non-convex to convex. + +Does anybody use that +in a proof to say, + +these things are preserved +across the operations? + +You said perimeter +was preserved. + +What about shortest paths? + +PROFESSOR: So is this +useful for something? + +Shortest paths are +certainly not preserved. + +Edge lengths are preserved. + +Of course, we know how to do +that with the carpenter's rule + +theorem, just staying in 2D, +so it's not that exciting. + +But the operations are +definitely a lot simpler. + +I think the easy +answer to your question + +is there are many +natural, simple moves, + +and this is the first one +that people considered, + +but actually, there +are a lot more, + +and I'm going to +talk about those. + +The main application I know +for this stuff is basically, + +people wanted to generate random +closed walks in 3D typically, + +and so they wanted to find +a small set of operations + +they could just perform +randomly and hope + +that that was a rapidly +mixing Markov chain, + +so eventually, you'd have +a kind of random thing. + +I don't think there +are any rapid mixing + +results, at least +that I'm aware of. + +In order to hope to +get the space randomly, + +you would at least have to +be able to make anything. + +So for that, the question is, +can you convexify anything, + +because if you can convexify +anything, then at least + +you can make anything, +more or less. + +So that's where these +questions come from. + +We focus more on +the universality, + +but I think what people care +about is this random generation + +business. + +To that end, of course, +for random generation, + +you don't really +care about crossings. + +And so another fun +extension which + +was in, I think, our +paper for the first time, + +although there's a weaker +version in Grunbaum's paper, + +if you start with a +non-crossing, this proof + +still works. + +You need to add a little +more to the argument. + +Either you decrease the number +of crossings, which can only + +happen a finite number of times, +or this kind of stuff works. + +You can make crossing polygons, +too, which is kind of cool. + +So that's the end +of basic flips. + +Then we have something called a +flip turn, which is kind of fun + +and in some ways better behaved, +and gets to your question + +of what else is preserved. + +So let's say you have +a pocket like this. + +So normally with a +flip, we would reflect. + +With a flip turn, you reflect +and then also flip this way, + +so it's the same as rotating +180 degrees about the center. + +In addition to +preserving perimeter, + +this preserves the +edge directions. + +This matches this, this matches +this, this matches this. + +It does not preserve +the edge order, however. + +Here, we preserve +the edge order. + +Here, we've reversed the +order of those three edges. + +So all this is really +doing is permuting + +the sequence of edges. + +The edge directions and the +edge lengths are all the same. + +So this means you could make +at most n factorial moves here. + +Immediately, it's different +from this situation + +where even for n +equals 4, you could + +have arbitrarily many moves. + +Here, it's at most n factorial. + +That was the original bound. + +It turns out every +polygon convexifies + +after order n +squared flip turns. + +It's a fun proof but I don't +have time to cover it here. + +That's flip turns. + +Then we go to deflations. + +This is the inverse of a flip. + +So suppose you take a polygon +and you do an operation + +that, if flipped, would result +in the original polygon, + +exactly the opposite of a flip. + +This was conjectured to also +finish after finite time, + +but in fact it doesn't. + +If you take any quadrilateral +satisfying Kawasaki, + +so if you add up the +opposite edge lengths + +and they're equal-- so 6 +plus 3 is 9, 4 plus 5 is 9-- + +then there it is at least +a flat limit possibly. + +That's the Kawasaki thing. + +And in fact, it will +converge to that flat limit + +and it will take infinite +time to get there. + +So that's kind of fun. + +It gets very hard to +draw the pictures. + +This is really the main example +of an infinitely deflating + +polygon. + +We have a paper called +"Deflating the Pentagon," which + +got some fun political +views at some point. + +It's about a +pentagon, five sides. + +And essentially, unless you have +a flat vertex, in which case + +you are quadrilateral, there +is no infinitely deflating + +pentagon, which means you can +deflate the pentagon always + +in finite time. + +It is open for +hexagons and higher + +whether there is another +example different + +from the quadrilateral. + +Then there's the idea of a pop. + +This is an even simpler +operation than a flip. + +You just take two +edges, like here we're + +taking these two edges, +and, ignoring crossings, + +you just flip as if +that were a pocket lid, + +so if this were a pocket. + +Then you get this polygon. + +Now here, you can be +forced to get crossings. + +No matter how you flip, +you might get a crossing. + +Still, we're wondering-- +who cares about crossings-- + +are pops enough to make +anything, or to convexify? + +And the answer is no. + +There's this set of polygons +called alternating polygons + +where the vertices +alternate between the x-axis + +and the y-axis. + +And you can prove that no +matter what pop you do, + +you are still an +alternating polygon, + +and alternating polygons, +you can also prove, + +are never convex, +so you're stuck. + +This was open for many years but +finally solved a few years ago. + +There's also pop turns, which +is where you take two edges + +and you do a 180 degree +rotation like this. + +And there, we can prove +if you allow crossings, + +you can convexify any polygon. + +I don't have a figure of that +because it's just an algorithm. + +We haven't actually run +it on a nice example. + +If you avoid crossings, we can +characterize when it's possible + +and when it's impossible. + +And those are pretty much +all the simple operations + +that at least have been studied. + +There's probably more to +think about, but that's it, + +and that's the end of +my part of the class. \ No newline at end of file diff --git a/K5n0BMKZR_Q.txt b/K5n0BMKZR_Q.txt new file mode 100644 index 0000000000000000000000000000000000000000..497e6260b3d360c75e6f9a64c865f6468ba9a8a4 --- /dev/null +++ b/K5n0BMKZR_Q.txt @@ -0,0 +1,431 @@ +PROFESSOR: Welcome to +another help session + +on recombinant DNA. + +Today, we're going to +be discussing about + +transformation and protein +expression. + +As you can imagine, there are +often many times we will need + +a large amount of protein. + +But it can be difficult to get +it from the original source. + +For example, you need insulin +to treat diabetes, but it's + +not exactly practical to get a +lot of insulin from humans. + +In order to get a lot of the +desired protein, often other + +organisms will be used to +express this protein. + +But it's a multi-step process. + +For example, let's say we want +to express our human insulin + +in bacteria. + +Well, the human gene has both +introns and exons, as you + +remember from lecture. + +Exons are what are actually +cut together in order to + +produce the final mature mRNA, +which is later used to express + +the protein. + +Bacteria, on the other hand, +don't have introns. + +They just have exons. + +So they are only capable of +reading a gene that just has + +the exons and then producing +the protein from that. + +In order to take a version of +the gene that's from the + +eukaryotic cell and get it +to be expressed in the + +prokaryotic, we first have to +make something called cDNA. + +So let's begin. + +We're going to take our +cell of interest. + +And the first step in creating +the cDNA is we're going to + +isolate the mRNA of interest-- + +this is the mRNA for insulin, +for example-- + +from the cell. + +And once we have our mRNA, we +are going to add something + +called reverse transcriptase. + +This is a protein that's a DNA +polymerase that's going to use + +the single-stranded RNA +as its template. + +So it's going to take the RNA +and it's going to put together + +this double-stranded DNA +that we're going + +to refer to as cDNA. + +So this is the DNA for the gene, +but unlike the original + +gene, it only has the exons. + +It doesn't have any +of the introns. + +The next step, of course, +is to get the + +cDNA into the bacteria. + +We do this using something +called a vector. + +The vector is just a means of +getting DNA into a cell. + +One common type of vector +is a plasmid. + +The plasmid is a circular piece +of DNA that the bacteria + +can then take up and read. + +The way we're going to get our +cDNA into this plasmid is + +through the use of restriction +enzymes. + +As you remember from our +previous help session, + +restriction enzymes can cut up +DNA and create these overhang + +of the nucleotides. + +So we're going to cut up the +cDNA, and we're going to cut + +up the plasmid, and they're +going to have overhangs that + +are complementary. + +This means that when we add +the cDNA to the plasmids, + +they're going to hybridize, +and then + +we can add DNA ligase. + +We add DNA ligase, it will +create a phosphodiester bond + +between the cDNA and the +plasmid vectors. + +And finally we'll get the cDNA +inserted into our plasmid. + +The next step, of course, is +getting the plasmid into the + +bacteria in order for the +protein to be expressed. + +There are multiple, different +ways to do this. + +One common way is called +heat shock. + +What happens is that the +bacteria is heated up and then + +cooled rapidly, and this creates +lots of little holes + +in the membrane, which +allow the plasma to + +get into the cell. + +Once you have the plasmid in +the bacteria, your job is + +pretty much done. + +Now the bacteria will naturally +express this + +protein, so you can grow up +the bacteria in large + +quantities and get a lot of +the protein of interest. + +Referring back briefly to the +vector, there are several + +parts that are important +for it to have. + +We're going to need to have the +origin of replication, the + +promoter, and the selection +marker. + +The origin of replication +initiation, or ORI, is + +necessary if we want the +bacteria to produce more + +copies of this plasmid. + +So once the plasmid gets into +the bacteria, if we don't have + +an ORI, as the bacteria grows +and reproduces, none of the + +daughter cells will +have this plasmid. + +We'll have to continually +transform them. + +However if it has the ORI, +as a bacteria grows and + +reproduces, it will also +replicate this plasmid. + +Another very important thing +to have is the promoter. + +The promoter is a section of DNA +which signals for the RNA + +polymerase to bind. + +The RNA's polymerase will bind +to the promoter, and then will + +proceed down the DNA on the +plasmid to read the actual + +gene and transcribe it. + +So the mRNA, which then +ultimately can + +be made into protein. + +Finally, you need a +selection marker. + +Now as we talked about earlier, +when you heat shock + +the bacteria, the plasmid +will get taken up. + +However, not all the +bacteria might take + +up some of the plasmid. + +In order to get rid of the +unwanted bacteria, the + +bacteria that doesn't have the +plasmid, we're going to use + +selection marker. + +A very common selection marker +for bacteria is antibiotic + +resistance. + +For example, if the plasmid +provides ampicillin + +resistance, then this means that +any bacteria that takes + +up the plasmid will be resistant +to ampicillin. + +The bacteria that don't will +still be vulnerable to it. + +So you could plate all of your +bacteria on a plate containing + +ampicillin, and the ones that +have the plasmid will survive. + +The ones that don't have the +plasmid will perish. + +So let's go once more to the +original example and discuss + +about what we're going to +need for our vector. + +So again, we want to express +human insulin in + +the bacterial system. + +There are six possibilities +for what we + +can need on our vector. + +You can need the bacterial +ORI, the human ORI, the + +bacterial promoter, the human +promoter, the bacterial + +selection marker, the human +selection marker. + +Pause for a minute. + +Give you a chance to decide +what you think the vector + +needs, and then we'll +go over it together. + +OK. + +Does it need a bacterial ORI? + +Yes. + +If we want to grow up a large +amount of insulin, we're going + +to put the plasmid +in the bacteria. + +The bacteria needs to create +more of this plasmid. + +Does it need human ORI? + +No, we're not actually assorting +the plasmid into a + +human cell. + +So the human cell is never +going to need to + +create more of them. + +Just the bacterial cell. + +What about a bacterial +promoter? + +Yes. + +Even though it's a human +gene, the promoter has + +to be for the bacteria. + +Because it's going to be the +bacterial RNA polymerase that + +will bind to the promoter, +and ultimately make the + +mRNA from the cDNA. + +What about a human promoter? + +No, we don't need a human +promoter because the human RNA + +polymerase won't be involved. + +Again, this is only going to +be in the bacterial cells. + +It's not going to be in the +human cell, so it doesn't need + +a human promoter. + +And finally for the selection +markers, once again, we only + +need the bacterial selection +marker, not the human + +selection marker. + +We're not dealing with full +human cells at this point. + +We're just dealing with a +plasmid, so we only need to + +select for bacteria cells that +have the plasmid of interest. + +This has been another help +section on recombinant DNA. + +Thank you for your time. \ No newline at end of file diff --git a/MJM1AzpB6Y4.txt b/MJM1AzpB6Y4.txt new file mode 100644 index 0000000000000000000000000000000000000000..6653093405c236ad6583e9f318ead9cf3a6651d8 --- /dev/null +++ b/MJM1AzpB6Y4.txt @@ -0,0 +1,587 @@ +align:start position:0% + +we got here finally in terms of position + + align:start position:0% +we got here finally in terms of position + + + align:start position:0% +we got here finally in terms of position +and in terms of momentum so this was not + + align:start position:0% +and in terms of momentum so this was not + + + align:start position:0% +and in terms of momentum so this was not +an accident that it worked for position + + align:start position:0% +an accident that it worked for position + + + align:start position:0% +an accident that it worked for position +and wave number + + align:start position:0% +and wave number + + + align:start position:0% +and wave number +it works with position and for momentum + + align:start position:0% +it works with position and for momentum + + + align:start position:0% +it works with position and for momentum +and remember this Phi of P now has + + align:start position:0% +and remember this Phi of P now has + + + align:start position:0% +and remember this Phi of P now has +interpretation of the weight that is + + align:start position:0% +interpretation of the weight that is + + + align:start position:0% +interpretation of the weight that is +associated with a plane wave of momentum + + align:start position:0% +associated with a plane wave of momentum + + + align:start position:0% +associated with a plane wave of momentum +P and you're summing over P in here so + + align:start position:0% +P and you're summing over P in here so + + + align:start position:0% +P and you're summing over P in here so +we'll do the natural thing that we did + + align:start position:0% +we'll do the natural thing that we did + + + align:start position:0% +we'll do the natural thing that we did +with X will interpret Phi of P squared + + align:start position:0% +with X will interpret Phi of P squared + + + align:start position:0% +with X will interpret Phi of P squared +Phi of P squared DP as the probability + + align:start position:0% +Phi of P squared DP as the probability + + + align:start position:0% +Phi of P squared DP as the probability +is the probability to find the particle + + align:start position:0% + + + + align:start position:0% + +with momentum in the range P P plus DP + + align:start position:0% +with momentum in the range P P plus DP + + + align:start position:0% +with momentum in the range P P plus DP +just the same way as we would say that + + align:start position:0% +just the same way as we would say that + + + align:start position:0% +just the same way as we would say that +size squared of X DX is the probability + + align:start position:0% +size squared of X DX is the probability + + + align:start position:0% +size squared of X DX is the probability +to find the particle between X and X + + align:start position:0% +to find the particle between X and X + + + align:start position:0% +to find the particle between X and X +plus DX so this is allowed now by the + + align:start position:0% +plus DX so this is allowed now by the + + + align:start position:0% +plus DX so this is allowed now by the +conservation of probability and this + + align:start position:0% +conservation of probability and this + + + align:start position:0% +conservation of probability and this +therefore makes sense it's a postulate + + align:start position:0% +therefore makes sense it's a postulate + + + align:start position:0% +therefore makes sense it's a postulate +though it's not something I can derive I + + align:start position:0% +though it's not something I can derive I + + + align:start position:0% +though it's not something I can derive I +can just argue that is consistent to + + align:start position:0% +can just argue that is consistent to + + + align:start position:0% +can just argue that is consistent to +think in that way and and that's the way + + align:start position:0% +think in that way and and that's the way + + + align:start position:0% +think in that way and and that's the way +we finally promote this Phi of P which + + align:start position:0% +we finally promote this Phi of P which + + + align:start position:0% +we finally promote this Phi of P which +did encode sigh of X + + align:start position:0% +did encode sigh of X + + + align:start position:0% +did encode sigh of X +five P has the same information of fire + + align:start position:0% +five P has the same information of fire + + + align:start position:0% +five P has the same information of fire +of X Phi of P is the weight of the + + align:start position:0% +of X Phi of P is the weight of the + + + align:start position:0% +of X Phi of P is the weight of the +superposition but finally it's given an + + align:start position:0% +superposition but finally it's given an + + + align:start position:0% +superposition but finally it's given an +probabilistic interpretation it + + align:start position:0% +probabilistic interpretation it + + + align:start position:0% +probabilistic interpretation it +represents a probability to find the + + align:start position:0% +represents a probability to find the + + + align:start position:0% +represents a probability to find the +particle with some momentum so this is + + align:start position:0% +particle with some momentum so this is + + + align:start position:0% +particle with some momentum so this is +what this is going to allow us to do + + align:start position:0% +what this is going to allow us to do + + + align:start position:0% +what this is going to allow us to do +expectation values in a minute but I + + align:start position:0% +expectation values in a minute but I + + + align:start position:0% +expectation values in a minute but I +want to close off this discussion by + + align:start position:0% +want to close off this discussion by + + + align:start position:0% +want to close off this discussion by +writing for you the three-dimensional + + align:start position:0% +writing for you the three-dimensional + + + align:start position:0% +writing for you the three-dimensional +versions of these equations 3d version + + align:start position:0% +versions of these equations 3d version + + + align:start position:0% +versions of these equations 3d version +of Fourier transform so this is what we + + align:start position:0% +of Fourier transform so this is what we + + + align:start position:0% +of Fourier transform so this is what we +want to rewrite so what would it be if + + align:start position:0% +want to rewrite so what would it be if + + + align:start position:0% +want to rewrite so what would it be if +size of the vector X since you're going + + align:start position:0% +size of the vector X since you're going + + + align:start position:0% +size of the vector X since you're going +to have three integrals because you're + + align:start position:0% +to have three integrals because you're + + + align:start position:0% +to have three integrals because you're +going to it over three components of + + align:start position:0% +going to it over three components of + + + align:start position:0% +going to it over three components of +movement that this factor appears three + + align:start position:0% +movement that this factor appears three + + + align:start position:0% +movement that this factor appears three +times so actually it's 2 pi H bar to the + + align:start position:0% +times so actually it's 2 pi H bar to the + + + align:start position:0% +times so actually it's 2 pi H bar to the +three-halves integral Phi of vector P e + + align:start position:0% +three-halves integral Phi of vector P e + + + align:start position:0% +three-halves integral Phi of vector P e +to the I vector P dot product vector X H + + align:start position:0% +to the I vector P dot product vector X H + + + align:start position:0% +to the I vector P dot product vector X H +bar V Cube P and Phi of P vector the + + align:start position:0% +bar V Cube P and Phi of P vector the + + + align:start position:0% +bar V Cube P and Phi of P vector the +inverse theorem same factor we keep the + + align:start position:0% +inverse theorem same factor we keep the + + + align:start position:0% +inverse theorem same factor we keep the +nice symmetry between X and P sy of X + + align:start position:0% +nice symmetry between X and P sy of X + + + align:start position:0% +nice symmetry between X and P sy of X +vector negative exponent same dot + + align:start position:0% +vector negative exponent same dot + + + align:start position:0% +vector negative exponent same dot +product but negative exponent D cube X + + align:start position:0% +product but negative exponent D cube X + + + align:start position:0% +product but negative exponent D cube X +so this are the three-dimensional + + align:start position:0% +so this are the three-dimensional + + + align:start position:0% +so this are the three-dimensional +versions of your X versus P + + align:start position:0% + + + + align:start position:0% + +and there is a three-dimensional version + + align:start position:0% +and there is a three-dimensional version + + + align:start position:0% +and there is a three-dimensional version +of parsable so oh there's a + + align:start position:0% +of parsable so oh there's a + + + align:start position:0% +of parsable so oh there's a +three-dimensional version of the Delta + + align:start position:0% +three-dimensional version of the Delta + + + align:start position:0% +three-dimensional version of the Delta +function just like we had a delta + + align:start position:0% +function just like we had a delta + + + align:start position:0% +function just like we had a delta +function here adult a function in + + align:start position:0% +function here adult a function in + + + align:start position:0% +function here adult a function in +three-dimensional space would be Delta + + align:start position:0% +three-dimensional space would be Delta + + + align:start position:0% +three-dimensional space would be Delta +cube X minus X prime would be 1 over 2 + + align:start position:0% +cube X minus X prime would be 1 over 2 + + + align:start position:0% +cube X minus X prime would be 1 over 2 +PI cubed integral D cubed K e to the I K + + align:start position:0% +PI cubed integral D cubed K e to the I K + + + align:start position:0% +PI cubed integral D cubed K e to the I K +vector X minus X prime vector it's all + + align:start position:0% +vector X minus X prime vector it's all + + + align:start position:0% +vector X minus X prime vector it's all +quite analogous I I think you should + + align:start position:0% +quite analogous I I think you should + + + align:start position:0% +quite analogous I I think you should +appreciate that you don't have to + + align:start position:0% +appreciate that you don't have to + + + align:start position:0% +appreciate that you don't have to +memorize them or anything like that they + + align:start position:0% +memorize them or anything like that they + + + align:start position:0% +memorize them or anything like that they +would be in any formula sheet but + + align:start position:0% +would be in any formula sheet but + + + align:start position:0% +would be in any formula sheet but +they're very analogous expressions + + align:start position:0% +they're very analogous expressions + + + align:start position:0% +they're very analogous expressions +percival also works in the same way and + + align:start position:0% +percival also works in the same way and + + + align:start position:0% +percival also works in the same way and +you have just as you would imagine that + + align:start position:0% +you have just as you would imagine that + + + align:start position:0% +you have just as you would imagine that +the interval all over 3-dimensional + + align:start position:0% +the interval all over 3-dimensional + + + align:start position:0% +the interval all over 3-dimensional +space of Phi of x squared is equal to + + align:start position:0% +space of Phi of x squared is equal to + + + align:start position:0% +space of Phi of x squared is equal to +the integral over 3-dimensional momentum + + align:start position:0% +the integral over 3-dimensional momentum + + + align:start position:0% +the integral over 3-dimensional momentum +space of Phi of P squared so the three + + align:start position:0% +space of Phi of P squared so the three + + + align:start position:0% +space of Phi of P squared so the three +results the phoria theorem the Delta + + align:start position:0% +results the phoria theorem the Delta + + + align:start position:0% +results the phoria theorem the Delta +function and Parsifal hold equally well \ No newline at end of file diff --git a/MMn7q1M7pGI.txt b/MMn7q1M7pGI.txt new file mode 100644 index 0000000000000000000000000000000000000000..7b4f7895a58c7fa868b52771a71046eefeec3725 --- /dev/null +++ b/MMn7q1M7pGI.txt @@ -0,0 +1,1243 @@ +align:start position:0% + +now we're ready to prove the law of + + align:start position:0% +now we're ready to prove the law of + + + align:start position:0% +now we're ready to prove the law of +large numbers and while we're at it to + + align:start position:0% +large numbers and while we're at it to + + + align:start position:0% +large numbers and while we're at it to +get a quantitative version which will be + + align:start position:0% +get a quantitative version which will be + + + align:start position:0% +get a quantitative version which will be +the basis for our theory of sampling and + + align:start position:0% +the basis for our theory of sampling and + + + align:start position:0% +the basis for our theory of sampling and +estimation so let's remember that the + + align:start position:0% +estimation so let's remember that the + + + align:start position:0% +estimation so let's remember that the +law of large numbers says that if you + + align:start position:0% +law of large numbers says that if you + + + align:start position:0% +law of large numbers says that if you +have n independent identically + + align:start position:0% +have n independent identically + + + align:start position:0% +have n independent identically +distributed random variables with mean + + align:start position:0% +distributed random variables with mean + + + align:start position:0% +distributed random variables with mean +mu and we let a n be their average then + + align:start position:0% +mu and we let a n be their average then + + + align:start position:0% +mu and we let a n be their average then +for every positive number Delta the + + align:start position:0% +for every positive number Delta the + + + align:start position:0% +for every positive number Delta the +probability that the average differ + + align:start position:0% +probability that the average differ + + + align:start position:0% +probability that the average differ +from the mean by more than Delta goes to + + align:start position:0% +from the mean by more than Delta goes to + + + align:start position:0% +from the mean by more than Delta goes to +zero as the number of Trials increases + + align:start position:0% +zero as the number of Trials increases + + + align:start position:0% +zero as the number of Trials increases +remember that means that uh if you tell + + align:start position:0% +remember that means that uh if you tell + + + align:start position:0% +remember that means that uh if you tell +me what you think close means um and + + align:start position:0% +me what you think close means um and + + + align:start position:0% +me what you think close means um and +what you think very likely means then I + + align:start position:0% +what you think very likely means then I + + + align:start position:0% +what you think very likely means then I +can guarantee that by doing enough + + align:start position:0% +can guarantee that by doing enough + + + align:start position:0% +can guarantee that by doing enough +trials uh the the likelihood that the + + align:start position:0% +trials uh the the likelihood that the + + + align:start position:0% +trials uh the the likelihood that the +mean will be that close to the average + + align:start position:0% +mean will be that close to the average + + + align:start position:0% +mean will be that close to the average +uh within will be outside the tolerance + + align:start position:0% +uh within will be outside the tolerance + + + align:start position:0% +uh within will be outside the tolerance +is as small as you thought small should + + align:start position:0% +is as small as you thought small should + + + align:start position:0% +is as small as you thought small should +be + + align:start position:0% +be + + + align:start position:0% +be +and we're ready for the proof but in the + + align:start position:0% +and we're ready for the proof but in the + + + align:start position:0% +and we're ready for the proof but in the +proof there's one extra fact that we're + + align:start position:0% +proof there's one extra fact that we're + + + align:start position:0% +proof there's one extra fact that we're +going to use that we didn't explicitly + + align:start position:0% +going to use that we didn't explicitly + + + align:start position:0% +going to use that we didn't explicitly +mention which is that not only are all + + align:start position:0% +mention which is that not only are all + + + align:start position:0% +mention which is that not only are all +of these random variables identically + + align:start position:0% +of these random variables identically + + + align:start position:0% +of these random variables identically +distributed and independent but we're + + align:start position:0% +distributed and independent but we're + + + align:start position:0% +distributed and independent but we're +actually going to assume that they have + + align:start position:0% +actually going to assume that they have + + + align:start position:0% +actually going to assume that they have +a variance now not every random variable + + align:start position:0% +a variance now not every random variable + + + align:start position:0% +a variance now not every random variable +has a finite variance even if it has a + + align:start position:0% +has a finite variance even if it has a + + + align:start position:0% +has a finite variance even if it has a +finite mean in fact there are random + + align:start position:0% +finite mean in fact there are random + + + align:start position:0% +finite mean in fact there are random +variables that don't even have finite + + align:start position:0% +variables that don't even have finite + + + align:start position:0% +variables that don't even have finite +means and we'll look at them uh on the + + align:start position:0% +means and we'll look at them uh on the + + + align:start position:0% +means and we'll look at them uh on the +last day of class but uh so we're going + + align:start position:0% +last day of class but uh so we're going + + + align:start position:0% +last day of class but uh so we're going +to going to explicitly assume that all + + align:start position:0% +to going to explicitly assume that all + + + align:start position:0% +to going to explicitly assume that all +of these random variables have the same + + align:start position:0% +of these random variables have the same + + + align:start position:0% +of these random variables have the same +variance namely the squ the standard + + align:start position:0% +variance namely the squ the standard + + + align:start position:0% +variance namely the squ the standard +deviation Sigma + + align:start position:0% +deviation Sigma + + + align:start position:0% +deviation Sigma +squared and we'll be using that fact in + + align:start position:0% +squared and we'll be using that fact in + + + align:start position:0% +squared and we'll be using that fact in +the proof all right now the first + + align:start position:0% +the proof all right now the first + + + align:start position:0% +the proof all right now the first +question to ask uh is what is the + + align:start position:0% +question to ask uh is what is the + + + align:start position:0% +question to ask uh is what is the +expectation of the average and the + + align:start position:0% +expectation of the average and the + + + align:start position:0% +expectation of the average and the +expectation of the average is simply the + + align:start position:0% +expectation of the average is simply the + + + align:start position:0% +expectation of the average is simply the +expectation let's prove that the + + align:start position:0% +expectation let's prove that the + + + align:start position:0% +expectation let's prove that the +expectation of the average is by + + align:start position:0% +expectation of the average is by + + + align:start position:0% +expectation of the average is by +definition the expectation of the sum of + + align:start position:0% +definition the expectation of the sum of + + + align:start position:0% +definition the expectation of the sum of +the RS Over N um and by additivity + + align:start position:0% +the RS Over N um and by additivity + + + align:start position:0% +the RS Over N um and by additivity +of uh expectation that's the sum of the + + align:start position:0% +of uh expectation that's the sum of the + + + align:start position:0% +of uh expectation that's the sum of the +expectation of each of the RS Over N but + + align:start position:0% +expectation of each of the RS Over N but + + + align:start position:0% +expectation of each of the RS Over N but +each of them has expectation mu so the + + align:start position:0% +each of them has expectation mu so the + + + align:start position:0% +each of them has expectation mu so the +numerator is n mu and the n's cancel and + + align:start position:0% +numerator is n mu and the n's cancel and + + + align:start position:0% +numerator is n mu and the n's cancel and +so and sure enough the average has the + + align:start position:0% +so and sure enough the average has the + + + align:start position:0% +so and sure enough the average has the +same expectation as each of the + + align:start position:0% +same expectation as each of the + + + align:start position:0% +same expectation as each of the +individual variables each of the + + align:start position:0% +individual variables each of the + + + align:start position:0% +individual variables each of the +trials now that lets us apply the chbby + + align:start position:0% +trials now that lets us apply the chbby + + + align:start position:0% +trials now that lets us apply the chbby +Chev bound to the random variable a n + + align:start position:0% +Chev bound to the random variable a n + + + align:start position:0% +Chev bound to the random variable a n +because now we know what its mean is and + + align:start position:0% +because now we know what its mean is and + + + align:start position:0% +because now we know what its mean is and +its mean is independent of n we can ask + + align:start position:0% +its mean is independent of n we can ask + + + align:start position:0% +its mean is independent of n we can ask +we can apply chbby Chev to the + + align:start position:0% +we can apply chbby Chev to the + + + align:start position:0% +we can apply chbby Chev to the +probability that the average of n trials + + align:start position:0% +probability that the average of n trials + + + align:start position:0% +probability that the average of n trials +uh differs from its mean by more than + + align:start position:0% +uh differs from its mean by more than + + + align:start position:0% +uh differs from its mean by more than +Delta and according to Chev that's + + align:start position:0% +Delta and according to Chev that's + + + align:start position:0% +Delta and according to Chev that's +bounded by the variance of the average + + align:start position:0% +bounded by the variance of the average + + + align:start position:0% +bounded by the variance of the average +divided by n squar so I will have proved + + align:start position:0% +divided by n squar so I will have proved + + + align:start position:0% +divided by n squar so I will have proved +the law of large numbers if I can prove + + align:start position:0% +the law of large numbers if I can prove + + + align:start position:0% +the law of large numbers if I can prove +that the limit as n approaches Infinity + + align:start position:0% +that the limit as n approaches Infinity + + + align:start position:0% +that the limit as n approaches Infinity +of the variance goes to zero because + + align:start position:0% +of the variance goes to zero because + + + align:start position:0% +of the variance goes to zero because +that means that the right hand side will + + align:start position:0% +that means that the right hand side will + + + align:start position:0% +that means that the right hand side will +be going to zero over Delta squ namely + + align:start position:0% +be going to zero over Delta squ namely + + + align:start position:0% +be going to zero over Delta squ namely +going to zero which is what the law of + + align:start position:0% +going to zero which is what the law of + + + align:start position:0% +going to zero which is what the law of +large numbers says so we've reduced the + + align:start position:0% +large numbers says so we've reduced the + + + align:start position:0% +large numbers says so we've reduced the +proof of the law of large numbers to + + align:start position:0% +proof of the law of large numbers to + + + align:start position:0% +proof of the law of large numbers to +proving that the variance goes to zero + + align:start position:0% +proving that the variance goes to zero + + + align:start position:0% +proving that the variance goes to zero +as n approaches Infinity where a n is + + align:start position:0% +as n approaches Infinity where a n is + + + align:start position:0% +as n approaches Infinity where a n is +the average of n identically distributed + + align:start position:0% +the average of n identically distributed + + + align:start position:0% +the average of n identically distributed +variables with common mean mu and + + align:start position:0% +variables with common mean mu and + + + align:start position:0% +variables with common mean mu and +standard deviation + + align:start position:0% +standard deviation + + + align:start position:0% +standard deviation +Sigma well let's calculate the variance + + align:start position:0% +Sigma well let's calculate the variance + + + align:start position:0% +Sigma well let's calculate the variance +of a an a n again is the is the average + + align:start position:0% +of a an a n again is the is the average + + + align:start position:0% +of a an a n again is the is the average +of the sum of the RS over n and since + + align:start position:0% +of the sum of the RS over n and since + + + align:start position:0% +of the sum of the RS over n and since +we're assuming Independence of the RS + + align:start position:0% +we're assuming Independence of the RS + + + align:start position:0% +we're assuming Independence of the RS +the variance sum Rule and it just tells + + align:start position:0% +the variance sum Rule and it just tells + + + align:start position:0% +the variance sum Rule and it just tells +us that this is the sum of the variances + + align:start position:0% +us that this is the sum of the variances + + + align:start position:0% +us that this is the sum of the variances +now if we factor out the r 1/ n now this + + align:start position:0% +now if we factor out the r 1/ n now this + + + align:start position:0% +now if we factor out the r 1/ n now this +is a factor of 1 / n times this sum when + + align:start position:0% +is a factor of 1 / n times this sum when + + + align:start position:0% +is a factor of 1 / n times this sum when +we factor a constant out of the variance + + align:start position:0% +we factor a constant out of the variance + + + align:start position:0% +we factor a constant out of the variance +it squares so the denominator here + + align:start position:0% +it squares so the denominator here + + + align:start position:0% +it squares so the denominator here +becomes n sared and that's critical and + + align:start position:0% +becomes n sared and that's critical and + + + align:start position:0% +becomes n sared and that's critical and +the numerator is the sum of the N Vari + + align:start position:0% +the numerator is the sum of the N Vari + + + align:start position:0% +the numerator is the sum of the N Vari +es now each variance is Sigma squ and + + align:start position:0% +es now each variance is Sigma squ and + + + align:start position:0% +es now each variance is Sigma squ and +we've got n of them so we wind up with n + + align:start position:0% +we've got n of them so we wind up with n + + + align:start position:0% +we've got n of them so we wind up with n +Sigma squ over n^ 2 which is of course + + align:start position:0% +Sigma squ over n^ 2 which is of course + + + align:start position:0% +Sigma squ over n^ 2 which is of course +equal to Sigma s over n and sigma square + + align:start position:0% +equal to Sigma s over n and sigma square + + + align:start position:0% +equal to Sigma s over n and sigma square +is a constant and N is going to Infinity + + align:start position:0% +is a constant and N is going to Infinity + + + align:start position:0% +is a constant and N is going to Infinity +so sure enough the right hand side goes + + align:start position:0% +so sure enough the right hand side goes + + + align:start position:0% +so sure enough the right hand side goes +to zero as n increases which is all we + + align:start position:0% +to zero as n increases which is all we + + + align:start position:0% +to zero as n increases which is all we +needed to do to conclude the weak law of + + align:start position:0% +needed to do to conclude the weak law of + + + align:start position:0% +needed to do to conclude the weak law of +large numbers now if we go back and look + + align:start position:0% +large numbers now if we go back and look + + + align:start position:0% +large numbers now if we go back and look +at this proof the only thing that it + + align:start position:0% +at this proof the only thing that it + + + align:start position:0% +at this proof the only thing that it +used about the r RS was that they had + + align:start position:0% +used about the r RS was that they had + + + align:start position:0% +used about the r RS was that they had +the same mean mu and they actually had + + align:start position:0% +the same mean mu and they actually had + + + align:start position:0% +the same mean mu and they actually had +the same variance Sigma St Sigma squar + + align:start position:0% +the same variance Sigma St Sigma squar + + + align:start position:0% +the same variance Sigma St Sigma squar +and they that the Varian is added that + + align:start position:0% +and they that the Varian is added that + + + align:start position:0% +and they that the Varian is added that +was the key step in the proof that the + + align:start position:0% +was the key step in the proof that the + + + align:start position:0% +was the key step in the proof that the +variance of the sum of the RS was equal + + align:start position:0% +variance of the sum of the RS was equal + + + align:start position:0% +variance of the sum of the RS was equal +to the sum of the variances now + + align:start position:0% +to the sum of the variances now + + + align:start position:0% +to the sum of the variances now +additivity of variances only requires + + align:start position:0% +additivity of variances only requires + + + align:start position:0% +additivity of variances only requires +pairwise Independence it didn't even + + align:start position:0% +pairwise Independence it didn't even + + + align:start position:0% +pairwise Independence it didn't even +require the hypothesis that they were + + align:start position:0% +require the hypothesis that they were + + + align:start position:0% +require the hypothesis that they were +mutually independent and it didn't + + align:start position:0% +mutually independent and it didn't + + + align:start position:0% +mutually independent and it didn't +require uh the previous proof that we + + align:start position:0% +require uh the previous proof that we + + + align:start position:0% +require uh the previous proof that we +went through did not ever use the fact + + align:start position:0% +went through did not ever use the fact + + + align:start position:0% +went through did not ever use the fact +that the r had the same distribution + + align:start position:0% +that the r had the same distribution + + + align:start position:0% +that the r had the same distribution +that they need not be identically + + align:start position:0% +that they need not be identically + + + align:start position:0% +that they need not be identically +distributed it was sufficient that they + + align:start position:0% +distributed it was sufficient that they + + + align:start position:0% +distributed it was sufficient that they +have the same mean we can summarize what + + align:start position:0% +have the same mean we can summarize what + + + align:start position:0% +have the same mean we can summarize what +we really proved when we thought we were + + align:start position:0% +we really proved when we thought we were + + + align:start position:0% +we really proved when we thought we were +proving the law of large numbers we + + align:start position:0% +proving the law of large numbers we + + + align:start position:0% +proving the law of large numbers we +actually proved a precise quantitative + + align:start position:0% +actually proved a precise quantitative + + + align:start position:0% +actually proved a precise quantitative +theorem that says that if R1 through RN + + align:start position:0% +theorem that says that if R1 through RN + + + align:start position:0% +theorem that says that if R1 through RN +are pairwise independent random + + align:start position:0% +are pairwise independent random + + + align:start position:0% +are pairwise independent random +variables with the same finite mean mu + + align:start position:0% +variables with the same finite mean mu + + + align:start position:0% +variables with the same finite mean mu +and variant Sigma Sigma squar and we let + + align:start position:0% +and variant Sigma Sigma squar and we let + + + align:start position:0% +and variant Sigma Sigma squar and we let +a n be the average of those R of those n + + align:start position:0% +a n be the average of those R of those n + + + align:start position:0% +a n be the average of those R of those n +variables then the probability that the + + align:start position:0% +variables then the probability that the + + + align:start position:0% +variables then the probability that the +average differs from the mean by more + + align:start position:0% +average differs from the mean by more + + + align:start position:0% +average differs from the mean by more +than Delta is less than or equal to this + + align:start position:0% +than Delta is less than or equal to this + + + align:start position:0% +than Delta is less than or equal to this +definite number that we derived 1 / n * + + align:start position:0% +definite number that we derived 1 / n * + + + align:start position:0% +definite number that we derived 1 / n * +Sigma over Delta squar and this was what + + align:start position:0% +Sigma over Delta squar and this was what + + + align:start position:0% +Sigma over Delta squar and this was what +we previously proved when we thought we + + align:start position:0% +we previously proved when we thought we + + + align:start position:0% +we previously proved when we thought we +were just proving the law of large + + align:start position:0% +were just proving the law of large + + + align:start position:0% +were just proving the law of large +numbers we actually got this much + + align:start position:0% +numbers we actually got this much + + + align:start position:0% +numbers we actually got this much +tighter quantitative theorem now what + + align:start position:0% +tighter quantitative theorem now what + + + align:start position:0% +tighter quantitative theorem now what +this tells us here is that now if you + + align:start position:0% +this tells us here is that now if you + + + align:start position:0% +this tells us here is that now if you +tell me what Delta is and you tell me + + align:start position:0% +tell me what Delta is and you tell me + + + align:start position:0% +tell me what Delta is and you tell me +how small you want this to be well I + + align:start position:0% +how small you want this to be well I + + + align:start position:0% +how small you want this to be well I +know what's I'm given Sigma and I and + + align:start position:0% +know what's I'm given Sigma and I and + + + align:start position:0% +know what's I'm given Sigma and I and +you give me the Delta that you specified + + align:start position:0% +you give me the Delta that you specified + + + align:start position:0% +you give me the Delta that you specified +and since uh if you tell me how small + + align:start position:0% +and since uh if you tell me how small + + + align:start position:0% +and since uh if you tell me how small +you want this to be I will know how big + + align:start position:0% +you want this to be I will know how big + + + align:start position:0% +you want this to be I will know how big +an N to choose so this tells me how big + + align:start position:0% +an N to choose so this tells me how big + + + align:start position:0% +an N to choose so this tells me how big +a sample I need how many tries I have to + + align:start position:0% +a sample I need how many tries I have to + + + align:start position:0% +a sample I need how many tries I have to +make in order to get the probability + + align:start position:0% +make in order to get the probability + + + align:start position:0% +make in order to get the probability +that the mean is within a specified + + align:start position:0% +that the mean is within a specified + + + align:start position:0% +that the mean is within a specified +tolerance Delta as small as you + + align:start position:0% +tolerance Delta as small as you + + + align:start position:0% +tolerance Delta as small as you +specified and that is our independent + + align:start position:0% +specified and that is our independent + + + align:start position:0% +specified and that is our independent +sampling theorem that's why it's called + + align:start position:0% +sampling theorem that's why it's called + + + align:start position:0% +sampling theorem that's why it's called +independent sampling because we now know + + align:start position:0% +independent sampling because we now know + + + align:start position:0% +independent sampling because we now know +how big a sample is needed to estimate + + align:start position:0% +how big a sample is needed to estimate + + + align:start position:0% +how big a sample is needed to estimate +the mean of any random variable with any + + align:start position:0% +the mean of any random variable with any + + + align:start position:0% +the mean of any random variable with any +desired tolerance and any desired + + align:start position:0% +desired tolerance and any desired + + + align:start position:0% +desired tolerance and any desired +probability where of course the variance + + align:start position:0% +probability where of course the variance + + + align:start position:0% +probability where of course the variance +has to be finite the tolerance has to be + + align:start position:0% +has to be finite the tolerance has to be + + + align:start position:0% +has to be finite the tolerance has to be +positive tolerance is Delta and the + + align:start position:0% +positive tolerance is Delta and the + + + align:start position:0% +positive tolerance is Delta and the +probability uh has to be less than one \ No newline at end of file diff --git a/O91G3Likq3w.txt b/O91G3Likq3w.txt new file mode 100644 index 0000000000000000000000000000000000000000..788f7d8f7058baa2d9e89b2a8398bae27b83ab5b --- /dev/null +++ b/O91G3Likq3w.txt @@ -0,0 +1,8347 @@ +align:start position:0% + +okay why don't we get + + align:start position:0% +okay why don't we get + + + align:start position:0% +okay why don't we get +started so we've been talking about DC + + align:start position:0% +started so we've been talking about DC + + + align:start position:0% +started so we've been talking about DC +to DC + + align:start position:0% +to DC + + + align:start position:0% +to DC +converters and you know sort of + + align:start position:0% +converters and you know sort of + + + align:start position:0% +converters and you know sort of +analyzing them and understanding what + + align:start position:0% +analyzing them and understanding what + + + align:start position:0% +analyzing them and understanding what +they'll do in in steady + + align:start position:0% +they'll do in in steady + + + align:start position:0% +they'll do in in steady +state and I'd like to today bring that + + align:start position:0% +state and I'd like to today bring that + + + align:start position:0% +state and I'd like to today bring that +maybe one step closer to things you have + + align:start position:0% +maybe one step closer to things you have + + + align:start position:0% +maybe one step closer to things you have +to think about to design one okay but + + align:start position:0% +to think about to design one okay but + + + align:start position:0% +to think about to design one okay but +just as a reminder + + align:start position:0% +just as a reminder + + + align:start position:0% +just as a reminder +last class we introduced what's known as + + align:start position:0% +last class we introduced what's known as + + + align:start position:0% +last class we introduced what's known as +the buck boost converter or the up or + + align:start position:0% +the buck boost converter or the up or + + + align:start position:0% +the buck boost converter or the up or +the inverting buck boost + + align:start position:0% + + + + align:start position:0% + +converter and one version of that looks + + align:start position:0% +converter and one version of that looks + + + align:start position:0% +converter and one version of that looks +like this we have an input voltage that + + align:start position:0% +like this we have an input voltage that + + + align:start position:0% +like this we have an input voltage that +I'll call + + align:start position:0% +I'll call + + + align:start position:0% +I'll call +V1 + + align:start position:0% +V1 + + + align:start position:0% +V1 +um for example a + + align:start position:0% +um for example a + + + align:start position:0% +um for example a +switch a + + align:start position:0% +switch a + + + align:start position:0% +switch a +diode here's my output that'll be + + align:start position:0% +diode here's my output that'll be + + + align:start position:0% +diode here's my output that'll be +V2 and then we have a filter capacitor + + align:start position:0% +V2 and then we have a filter capacitor + + + align:start position:0% +V2 and then we have a filter capacitor +in this example I'm going to put the + + align:start position:0% +in this example I'm going to put the + + + align:start position:0% +in this example I'm going to put the +filter capacitor + + align:start position:0% +filter capacitor + + + align:start position:0% +filter capacitor +here okay because this is the sort of + + align:start position:0% +here okay because this is the sort of + + + align:start position:0% +here okay because this is the sort of +the actual switching Loop and then an + + align:start position:0% +the actual switching Loop and then an + + + align:start position:0% +the actual switching Loop and then an +inductor where we have + + align:start position:0% +inductor where we have + + + align:start position:0% +inductor where we have +I and right and what we've said so far + + align:start position:0% +I and right and what we've said so far + + + align:start position:0% +I and right and what we've said so far +is let's think about the case where um L + + align:start position:0% +is let's think about the case where um L + + + align:start position:0% +is let's think about the case where um L +and C are + + align:start position:0% +and C are + + + align:start position:0% +and C are +big right that that they're + + align:start position:0% +big right that that they're + + + align:start position:0% +big right that that they're +approximately infinite and that's not a + + align:start position:0% +approximately infinite and that's not a + + + align:start position:0% +approximately infinite and that's not a +bad place to start for analysis because + + align:start position:0% +bad place to start for analysis because + + + align:start position:0% +bad place to start for analysis because +you can learn a lot of things about that + + align:start position:0% +you can learn a lot of things about that + + + align:start position:0% +you can learn a lot of things about that +and what that means is that I is + + align:start position:0% +and what that means is that I is + + + align:start position:0% +and what that means is that I is +approximately equal to its DC value I + + align:start position:0% +approximately equal to its DC value I + + + align:start position:0% +approximately equal to its DC value I +and VC is approximately equal to its DC + + align:start position:0% +and VC is approximately equal to its DC + + + align:start position:0% +and VC is approximately equal to its DC +value Capital VC okay we said + + align:start position:0% +value Capital VC okay we said + + + align:start position:0% +value Capital VC okay we said +okay um if I had to think + + align:start position:0% +okay um if I had to think + + + align:start position:0% +okay um if I had to think +about uh this + + align:start position:0% +about uh this + + + align:start position:0% +about uh this +converter right I might think about the + + align:start position:0% +converter right I might think about the + + + align:start position:0% +converter right I might think about the +switch voltage V + + align:start position:0% +switch voltage V + + + align:start position:0% +switch voltage V +switch and the switch current I + + align:start position:0% +switch and the switch current I + + + align:start position:0% +switch and the switch current I +switch and the diode voltage + + align:start position:0% +switch and the diode voltage + + + align:start position:0% +switch and the diode voltage +VD and the diode current + + align:start position:0% +VD and the diode current + + + align:start position:0% +VD and the diode current +ID right and what we discovered about + + align:start position:0% +ID right and what we discovered about + + + align:start position:0% +ID right and what we discovered about +this converter last + + align:start position:0% +this converter last + + + align:start position:0% +this converter last +time is that if I thought of here I have + + align:start position:0% +time is that if I thought of here I have + + + align:start position:0% +time is that if I thought of here I have +say an input current that I'm going to + + align:start position:0% +say an input current that I'm going to + + + align:start position:0% +say an input current that I'm going to +call + + align:start position:0% +call + + + align:start position:0% +call +i1 and an output current um that I'm + + align:start position:0% +i1 and an output current um that I'm + + + align:start position:0% +i1 and an output current um that I'm +going to call + + align:start position:0% +going to call + + + align:start position:0% +going to call +I2 okay and if I said okay suppose this + + align:start position:0% +I2 okay and if I said okay suppose this + + + align:start position:0% +I2 okay and if I said okay suppose this +thing filters perfect + + align:start position:0% +thing filters perfect + + + align:start position:0% +thing filters perfect +and i1 is approximately equal to its DC + + align:start position:0% +and i1 is approximately equal to its DC + + + align:start position:0% +and i1 is approximately equal to its DC +value capital i1 and I2 is approximately + + align:start position:0% +value capital i1 and I2 is approximately + + + align:start position:0% +value capital i1 and I2 is approximately +equal to it DC value Capital I2 and in + + align:start position:0% +equal to it DC value Capital I2 and in + + + align:start position:0% +equal to it DC value Capital I2 and in +order to really get that you'd probably + + align:start position:0% +order to really get that you'd probably + + + align:start position:0% +order to really get that you'd probably +need a tiny bit of source impedance here + + align:start position:0% +need a tiny bit of source impedance here + + + align:start position:0% +need a tiny bit of source impedance here +but let's assume that's the case right + + align:start position:0% +but let's assume that's the case right + + + align:start position:0% +but let's assume that's the case right +what we saw for this + + align:start position:0% +what we saw for this + + + align:start position:0% +what we saw for this +converter is that + + align:start position:0% +converter is that + + + align:start position:0% +converter is that +ilil the DC + + align:start position:0% +ilil the DC + + + align:start position:0% +ilil the DC +current in the inductor is equal to the + + align:start position:0% +current in the inductor is equal to the + + + align:start position:0% +current in the inductor is equal to the +magnitude of i1 plus the magnitude of I + + align:start position:0% +magnitude of i1 plus the magnitude of I + + + align:start position:0% +magnitude of i1 plus the magnitude of I +2 and the DC capacitor voltage + + align:start position:0% +2 and the DC capacitor voltage + + + align:start position:0% +2 and the DC capacitor voltage +VC is equal to the magnitude of vc1 + + align:start position:0% +VC is equal to the magnitude of vc1 + + + align:start position:0% +VC is equal to the magnitude of vc1 +V1 plus the magnitude of + + align:start position:0% +V1 plus the magnitude of + + + align:start position:0% +V1 plus the magnitude of +V2 okay and so basically the capacitor + + align:start position:0% +V2 okay and so basically the capacitor + + + align:start position:0% +V2 okay and so basically the capacitor +has to see the sum of the magnitudes of + + align:start position:0% +has to see the sum of the magnitudes of + + + align:start position:0% +has to see the sum of the magnitudes of +the input and output voltage and the + + align:start position:0% +the input and output voltage and the + + + align:start position:0% +the input and output voltage and the +inductor current carries the + + align:start position:0% +inductor current carries the + + + align:start position:0% +inductor current carries the +um sum of the + + align:start position:0% +um sum of the + + + align:start position:0% +um sum of the +uh input and output currents + + align:start position:0% +uh input and output currents + + + align:start position:0% +uh input and output currents +okay and then if I thought well okay + + align:start position:0% +okay and then if I thought well okay + + + align:start position:0% +okay and then if I thought well okay +what is the switch + + align:start position:0% + + + + align:start position:0% + +voltage okay when the switch is off what + + align:start position:0% +voltage okay when the switch is off what + + + align:start position:0% +voltage okay when the switch is off what +voltage does it block well that blocks + + align:start position:0% +voltage does it block well that blocks + + + align:start position:0% +voltage does it block well that blocks +VC and the same thing when the diode is + + align:start position:0% +VC and the same thing when the diode is + + + align:start position:0% +VC and the same thing when the diode is +off it also blocks VC so V switch Max is + + align:start position:0% +off it also blocks VC so V switch Max is + + + align:start position:0% +off it also blocks VC so V switch Max is +equal to VD + + align:start position:0% +equal to VD + + + align:start position:0% +equal to VD +Max is equal to VC which is equal to the + + align:start position:0% +Max is equal to VC which is equal to the + + + align:start position:0% +Max is equal to VC which is equal to the +magnitude of V1 1 plus the magnitude of + + align:start position:0% +magnitude of V1 1 plus the magnitude of + + + align:start position:0% +magnitude of V1 1 plus the magnitude of +V2 and if I thought of I switch + + align:start position:0% +V2 and if I thought of I switch + + + align:start position:0% +V2 and if I thought of I switch +Max and ID Max well when they're on they + + align:start position:0% +Max and ID Max well when they're on they + + + align:start position:0% +Max and ID Max well when they're on they +carry the inductor + + align:start position:0% + + + + align:start position:0% + +current which is the magnitude of the + + align:start position:0% +current which is the magnitude of the + + + align:start position:0% +current which is the magnitude of the +input current and the output current the + + align:start position:0% +input current and the output current the + + + align:start position:0% +input current and the output current the +DC input and output current okay so at + + align:start position:0% +DC input and output current okay so at + + + align:start position:0% +DC input and output current okay so at +least now I have a sense of what the + + align:start position:0% +least now I have a sense of what the + + + align:start position:0% +least now I have a sense of what the +stresses are on the diodes and and + + align:start position:0% +stresses are on the diodes and and + + + align:start position:0% +stresses are on the diodes and and +transistors and the inductor and + + align:start position:0% +transistors and the inductor and + + + align:start position:0% +transistors and the inductor and +capacitor right why do I care about that + + align:start position:0% +capacitor right why do I care about that + + + align:start position:0% +capacitor right why do I care about that +because ultimately I have to go buy + + align:start position:0% +because ultimately I have to go buy + + + align:start position:0% +because ultimately I have to go buy +switches that can carry and diodes that + + align:start position:0% +switches that can carry and diodes that + + + align:start position:0% +switches that can carry and diodes that +can carry the current without blowing up + + align:start position:0% +can carry the current without blowing up + + + align:start position:0% +can carry the current without blowing up +and can block the voltage without + + align:start position:0% +and can block the voltage without + + + align:start position:0% +and can block the voltage without +blowing up and I've got to go buy + + align:start position:0% +blowing up and I've got to go buy + + + align:start position:0% +blowing up and I've got to go buy +capacitors that can block the voltage + + align:start position:0% +capacitors that can block the voltage + + + align:start position:0% +capacitors that can block the voltage +and inductors that can carry the current + + align:start position:0% +and inductors that can carry the current + + + align:start position:0% +and inductors that can carry the current +right so we have to start going through + + align:start position:0% +right so we have to start going through + + + align:start position:0% +right so we have to start going through +this analysis to say how much voltage + + align:start position:0% +this analysis to say how much voltage + + + align:start position:0% +this analysis to say how much voltage +and current do I need in the circuit + + align:start position:0% +and current do I need in the circuit + + + align:start position:0% +and current do I need in the circuit +okay how does this circuit compare to + + align:start position:0% +okay how does this circuit compare to + + + align:start position:0% +okay how does this circuit compare to +like a buck converter or a boost + + align:start position:0% +like a buck converter or a boost + + + align:start position:0% +like a buck converter or a boost +converter okay well if I took + + align:start position:0% +converter okay well if I took + + + align:start position:0% +converter okay well if I took +my buck + + align:start position:0% +my buck + + + align:start position:0% +my buck +converter okay so here's my buck + + align:start position:0% +converter okay so here's my buck + + + align:start position:0% +converter okay so here's my buck +converter in this + + align:start position:0% +converter in this + + + align:start position:0% +converter in this +case I'm going to put the I'm going to + + align:start position:0% +case I'm going to put the I'm going to + + + align:start position:0% +case I'm going to put the I'm going to +think about the capacitor at the input + + align:start position:0% +think about the capacitor at the input + + + align:start position:0% +think about the capacitor at the input +because that's where the switching + + align:start position:0% +because that's where the switching + + + align:start position:0% +because that's where the switching +current goes okay and here's my switch + + align:start position:0% +current goes okay and here's my switch + + + align:start position:0% +current goes okay and here's my switch +here's my + + align:start position:0% +here's my + + + align:start position:0% +here's my +diode and here's my inductor I won't + + align:start position:0% +diode and here's my inductor I won't + + + align:start position:0% +diode and here's my inductor I won't +worry about I don't actually need an + + align:start position:0% +worry about I don't actually need an + + + align:start position:0% +worry about I don't actually need an +capacitor at the output although I would + + align:start position:0% +capacitor at the output although I would + + + align:start position:0% +capacitor at the output although I would +typically put one so here's V2 so I + + align:start position:0% +typically put one so here's V2 so I + + + align:start position:0% +typically put one so here's V2 so I +could again think of V + + align:start position:0% +could again think of V + + + align:start position:0% +could again think of V +switch and I + + align:start position:0% +switch and I + + + align:start position:0% +switch and I +switch and + + align:start position:0% +switch and + + + align:start position:0% +switch and +VD and + + align:start position:0% +VD and + + + align:start position:0% +VD and +ID all + + align:start position:0% +ID all + + + align:start position:0% +ID all +right this would + + align:start position:0% +right this would + + + align:start position:0% +right this would +be + + align:start position:0% +be + + + align:start position:0% +be +VC and this would be + + align:start position:0% +VC and this would be + + + align:start position:0% +VC and this would be +I and again I'm going to think of LC lnc + + align:start position:0% +I and again I'm going to think of LC lnc + + + align:start position:0% +I and again I'm going to think of LC lnc +big right really really big so that + + align:start position:0% +big right really really big so that + + + align:start position:0% +big right really really big so that +basically the inductor current and the + + align:start position:0% +basically the inductor current and the + + + align:start position:0% +basically the inductor current and the +capacitor voltage here here are + + align:start position:0% +capacitor voltage here here are + + + align:start position:0% +capacitor voltage here here are +basically constant + + align:start position:0% +basically constant + + + align:start position:0% +basically constant +okay in that case what I get is V + + align:start position:0% +okay in that case what I get is V + + + align:start position:0% +okay in that case what I get is V +switch when it's off and VD when it's + + align:start position:0% +switch when it's off and VD when it's + + + align:start position:0% +switch when it's off and VD when it's +off are both equal to this capacitor + + align:start position:0% +off are both equal to this capacitor + + + align:start position:0% +off are both equal to this capacitor +voltage which is equal to + + align:start position:0% +voltage which is equal to + + + align:start position:0% +voltage which is equal to +V1 right and I + + align:start position:0% +V1 right and I + + + align:start position:0% +V1 right and I +switch equals ID when when the switch + + align:start position:0% +switch equals ID when when the switch + + + align:start position:0% +switch equals ID when when the switch +and diode are on they carry the inductor + + align:start position:0% +and diode are on they carry the inductor + + + align:start position:0% +and diode are on they carry the inductor +current + + align:start position:0% +current + + + align:start position:0% +current +which is also equal to I2 if the + + align:start position:0% +which is also equal to I2 if the + + + align:start position:0% +which is also equal to I2 if the +inductor current is really big and I + + align:start position:0% +inductor current is really big and I + + + align:start position:0% +inductor current is really big and I +just have a DC current right and this is + + align:start position:0% +just have a DC current right and this is + + + align:start position:0% +just have a DC current right and this is +the + + align:start position:0% +the + + + align:start position:0% +the +i1 this is + + align:start position:0% +i1 this is + + + align:start position:0% +i1 this is +I2 so that's for a buck + + align:start position:0% +I2 so that's for a buck + + + align:start position:0% +I2 so that's for a buck +converter what about a boost converter + + align:start position:0% +converter what about a boost converter + + + align:start position:0% +converter what about a boost converter +well a boost converter looked like this + + align:start position:0% +well a boost converter looked like this + + + align:start position:0% +well a boost converter looked like this +here's + + align:start position:0% + + + + align:start position:0% + +V1 here's I + + align:start position:0% + + + + align:start position:0% + +and in this case I'm going to put the + + align:start position:0% +and in this case I'm going to put the + + + align:start position:0% +and in this case I'm going to put the +capacitor here because the pulse current + + align:start position:0% +capacitor here because the pulse current + + + align:start position:0% +capacitor here because the pulse current +comes through the + + align:start position:0% +comes through the + + + align:start position:0% +comes through the +diode + + align:start position:0% +diode + + + align:start position:0% +diode +okay and here's + + align:start position:0% +okay and here's + + + align:start position:0% +okay and here's +V2 okay so again I have sort of V + + align:start position:0% +V2 okay so again I have sort of V + + + align:start position:0% +V2 okay so again I have sort of V +switch I + + align:start position:0% + + + + align:start position:0% + +switch DD and + + align:start position:0% +switch DD and + + + align:start position:0% +switch DD and +ID okay now in this + + align:start position:0% +ID okay now in this + + + align:start position:0% +ID okay now in this +case I is again constant if L and C are + + align:start position:0% +case I is again constant if L and C are + + + align:start position:0% +case I is again constant if L and C are +big okay so that the switch current and + + align:start position:0% +big okay so that the switch current and + + + align:start position:0% +big okay so that the switch current and +the diode current when they're + + align:start position:0% +the diode current when they're + + + align:start position:0% +the diode current when they're +on + + align:start position:0% + + + + align:start position:0% + +um is equal to i l which is also equal + + align:start position:0% +um is equal to i l which is also equal + + + align:start position:0% +um is equal to i l which is also equal +to i1 right because whatever the current + + align:start position:0% +to i1 right because whatever the current + + + align:start position:0% +to i1 right because whatever the current +is coming out of i1 is now the current + + align:start position:0% +is coming out of i1 is now the current + + + align:start position:0% +is coming out of i1 is now the current +that's being switched through the diode + + align:start position:0% +that's being switched through the diode + + + align:start position:0% +that's being switched through the diode +in the + + align:start position:0% +in the + + + align:start position:0% +in the +transistor um V switch is equal to VD is + + align:start position:0% +transistor um V switch is equal to VD is + + + align:start position:0% +transistor um V switch is equal to VD is +equal to + + align:start position:0% + + + + align:start position:0% + +VC which is equal to V two in this + + align:start position:0% +VC which is equal to V two in this + + + align:start position:0% +VC which is equal to V two in this +case okay so why am I going through + + align:start position:0% +case okay so why am I going through + + + align:start position:0% +case okay so why am I going through +this well for either the bucker boost + + align:start position:0% +this well for either the bucker boost + + + align:start position:0% +this well for either the bucker boost +converter keep in mind in the Boost + + align:start position:0% +converter keep in mind in the Boost + + + align:start position:0% +converter keep in mind in the Boost +converter V2 is the big voltage between + + align:start position:0% +converter V2 is the big voltage between + + + align:start position:0% +converter V2 is the big voltage between +the input and output voltage and I and + + align:start position:0% +the input and output voltage and I and + + + align:start position:0% +the input and output voltage and I and +i1 is the bigger of the currents between + + align:start position:0% +i1 is the bigger of the currents between + + + align:start position:0% +i1 is the bigger of the currents between +the input and output + + align:start position:0% +the input and output + + + align:start position:0% +the input and output +current + + align:start position:0% +current + + + align:start position:0% +current +likewise the switch voltage is V1 that's + + align:start position:0% +likewise the switch voltage is V1 that's + + + align:start position:0% +likewise the switch voltage is V1 that's +the bigger of the input and output + + align:start position:0% +the bigger of the input and output + + + align:start position:0% +the bigger of the input and output +voltage right + + align:start position:0% +voltage right + + + align:start position:0% +voltage right +and the current is I2 which is the + + align:start position:0% +and the current is I2 which is the + + + align:start position:0% +and the current is I2 which is the +bigger of the input and output current + + align:start position:0% +bigger of the input and output current + + + align:start position:0% +bigger of the input and output current +so for either of these converters I + + align:start position:0% +so for either of these converters I + + + align:start position:0% +so for either of these converters I +might write the the V switch is equal to + + align:start position:0% +might write the the V switch is equal to + + + align:start position:0% +might write the the V switch is equal to +V diode which is equal to the + + align:start position:0% +V diode which is equal to the + + + align:start position:0% +V diode which is equal to the +maximum of magnitude of V1 and + + align:start position:0% +maximum of magnitude of V1 and + + + align:start position:0% +maximum of magnitude of V1 and +V2 and I and this is also equal to the + + align:start position:0% +V2 and I and this is also equal to the + + + align:start position:0% +V2 and I and this is also equal to the +capacitor + + align:start position:0% +capacitor + + + align:start position:0% +capacitor +voltage and the inductor current is + + align:start position:0% +voltage and the inductor current is + + + align:start position:0% +voltage and the inductor current is +equal to the switch current + + align:start position:0% +equal to the switch current + + + align:start position:0% +equal to the switch current +is equal to the diode current is equal + + align:start position:0% +is equal to the diode current is equal + + + align:start position:0% +is equal to the diode current is equal +to the + + align:start position:0% +to the + + + align:start position:0% +to the +maximum of i1 and + + align:start position:0% +maximum of i1 and + + + align:start position:0% +maximum of i1 and +I2 okay so how do these two + + align:start position:0% +I2 okay so how do these two + + + align:start position:0% +I2 okay so how do these two +compare right the buck and the Boost + + align:start position:0% +compare right the buck and the Boost + + + align:start position:0% +compare right the buck and the Boost +converter can only do a very specific + + align:start position:0% +converter can only do a very specific + + + align:start position:0% +converter can only do a very specific +function right one can step down the + + align:start position:0% +function right one can step down the + + + align:start position:0% +function right one can step down the +other can step up they can't go both do + + align:start position:0% +other can step up they can't go both do + + + align:start position:0% +other can step up they can't go both do +both + + align:start position:0% +both + + + align:start position:0% +both +right but the stresses on them in either + + align:start position:0% +right but the stresses on them in either + + + align:start position:0% +right but the stresses on them in either +case basically the switch in the dial + + align:start position:0% +case basically the switch in the dial + + + align:start position:0% +case basically the switch in the dial +and the capacitor see the maximum of the + + align:start position:0% +and the capacitor see the maximum of the + + + align:start position:0% +and the capacitor see the maximum of the +input out output voltages and the indu + + align:start position:0% +input out output voltages and the indu + + + align:start position:0% +input out output voltages and the indu +switch current in the died currency the + + align:start position:0% +switch current in the died currency the + + + align:start position:0% +switch current in the died currency the +maximum of the input and output + + align:start position:0% +maximum of the input and output + + + align:start position:0% +maximum of the input and output +currents if I use a buck boost + + align:start position:0% +currents if I use a buck boost + + + align:start position:0% +currents if I use a buck boost +converter I can go up or down at least + + align:start position:0% +converter I can go up or down at least + + + align:start position:0% +converter I can go up or down at least +in magnitude but now I see higher + + align:start position:0% +in magnitude but now I see higher + + + align:start position:0% +in magnitude but now I see higher +stresses instead of seeing the maximum + + align:start position:0% +stresses instead of seeing the maximum + + + align:start position:0% +stresses instead of seeing the maximum +of the input output voltage I see the + + align:start position:0% +of the input output voltage I see the + + + align:start position:0% +of the input output voltage I see the +sum of the input and output voltage + + align:start position:0% +sum of the input and output voltage + + + align:start position:0% +sum of the input and output voltage +magnitudes and the sum of the input + + align:start position:0% +magnitudes and the sum of the input + + + align:start position:0% +magnitudes and the sum of the input +output current magnitudes right that + + align:start position:0% +output current magnitudes right that + + + align:start position:0% +output current magnitudes right that +means for a given conversion ratio the + + align:start position:0% +means for a given conversion ratio the + + + align:start position:0% +means for a given conversion ratio the +buck boost converter is going to have a + + align:start position:0% +buck boost converter is going to have a + + + align:start position:0% +buck boost converter is going to have a +higher stress on the switches and the + + align:start position:0% +higher stress on the switches and the + + + align:start position:0% +higher stress on the switches and the +dodes and the inductors and + + align:start position:0% +dodes and the inductors and + + + align:start position:0% +dodes and the inductors and +capacitors than a buck converter or a + + align:start position:0% +capacitors than a buck converter or a + + + align:start position:0% +capacitors than a buck converter or a +boost converter okay why is + + align:start position:0% +boost converter okay why is + + + align:start position:0% +boost converter okay why is +that in a buck boost converter remember + + align:start position:0% +that in a buck boost converter remember + + + align:start position:0% +that in a buck boost converter remember +we said how it ran was basically I take + + align:start position:0% +we said how it ran was basically I take + + + align:start position:0% +we said how it ran was basically I take +energy from the input I put it into the + + align:start position:0% +energy from the input I put it into the + + + align:start position:0% +energy from the input I put it into the +inductor in the first part of the cycle + + align:start position:0% +inductor in the first part of the cycle + + + align:start position:0% +inductor in the first part of the cycle +and then the second part of the cycle I + + align:start position:0% +and then the second part of the cycle I + + + align:start position:0% +and then the second part of the cycle I +take that energy out of the inductor and + + align:start position:0% +take that energy out of the inductor and + + + align:start position:0% +take that energy out of the inductor and +put it in the output so all of the + + align:start position:0% +put it in the output so all of the + + + align:start position:0% +put it in the output so all of the +energy flowing through the circuit from + + align:start position:0% +energy flowing through the circuit from + + + align:start position:0% +energy flowing through the circuit from +the input to the output ultimately got + + align:start position:0% +the input to the output ultimately got + + + align:start position:0% +the input to the output ultimately got +stored in that + + align:start position:0% +stored in that + + + align:start position:0% +stored in that +inductor + + align:start position:0% +inductor + + + align:start position:0% +inductor +okay with a buck converter or a boost + + align:start position:0% +okay with a buck converter or a boost + + + align:start position:0% +okay with a buck converter or a boost +converter that's not quite true in the + + align:start position:0% +converter that's not quite true in the + + + align:start position:0% +converter that's not quite true in the +first part of the cycle we turn the + + align:start position:0% +first part of the cycle we turn the + + + align:start position:0% +first part of the cycle we turn the +switch on and we store up some energy in + + align:start position:0% +switch on and we store up some energy in + + + align:start position:0% +switch on and we store up some energy in +the inductor but we also have direct + + align:start position:0% +the inductor but we also have direct + + + align:start position:0% +the inductor but we also have direct +current path from the input to the + + align:start position:0% +current path from the input to the + + + align:start position:0% +current path from the input to the +output through the + + align:start position:0% +output through the + + + align:start position:0% +output through the +inductor and in the second part of the + + align:start position:0% +inductor and in the second part of the + + + align:start position:0% +inductor and in the second part of the +cycle we take the energy out of the + + align:start position:0% +cycle we take the energy out of the + + + align:start position:0% +cycle we take the energy out of the +inductor and put it in the output so in + + align:start position:0% +inductor and put it in the output so in + + + align:start position:0% +inductor and put it in the output so in +a buck converter only part of the energy + + align:start position:0% +a buck converter only part of the energy + + + align:start position:0% +a buck converter only part of the energy +ends up stored in this in the inductor + + align:start position:0% +ends up stored in this in the inductor + + + align:start position:0% +ends up stored in this in the inductor +and part of it sort of flows straight + + align:start position:0% +and part of it sort of flows straight + + + align:start position:0% +and part of it sort of flows straight +through from the input to the output and + + align:start position:0% +through from the input to the output and + + + align:start position:0% +through from the input to the output and +the same thing can be said for the Boost + + align:start position:0% +the same thing can be said for the Boost + + + align:start position:0% +the same thing can be said for the Boost +converter the consequence of this is is + + align:start position:0% +converter the consequence of this is is + + + align:start position:0% +converter the consequence of this is is +that to do a given conversion function + + align:start position:0% +that to do a given conversion function + + + align:start position:0% +that to do a given conversion function +the buck boost converter imposes much + + align:start position:0% +the buck boost converter imposes much + + + align:start position:0% +the buck boost converter imposes much +greater stresses on its components than + + align:start position:0% +greater stresses on its components than + + + align:start position:0% +greater stresses on its components than +the buck converter or the Boost + + align:start position:0% +the buck converter or the Boost + + + align:start position:0% +the buck converter or the Boost +converter all right so we can get away + + align:start position:0% +converter all right so we can get away + + + align:start position:0% +converter all right so we can get away +with a lot of things + + align:start position:0% +with a lot of things + + + align:start position:0% +with a lot of things +in terms of reducing the stresses on the + + align:start position:0% +in terms of reducing the stresses on the + + + align:start position:0% +in terms of reducing the stresses on the +component by being in this sort of + + align:start position:0% +component by being in this sort of + + + align:start position:0% +component by being in this sort of +direct conversion approach where I'm + + align:start position:0% +direct conversion approach where I'm + + + align:start position:0% +direct conversion approach where I'm +sort of not storing all the inter energy + + align:start position:0% +sort of not storing all the inter energy + + + align:start position:0% +sort of not storing all the inter energy +in intermediate form than I can with a + + align:start position:0% +in intermediate form than I can with a + + + align:start position:0% +in intermediate form than I can with a +buck boost + + align:start position:0% +buck boost + + + align:start position:0% +buck boost +converter questions about that or about + + align:start position:0% +converter questions about that or about + + + align:start position:0% +converter questions about that or about +any of the prior + + align:start position:0% + + + + align:start position:0% + +material so one of the things we're + + align:start position:0% +material so one of the things we're + + + align:start position:0% +material so one of the things we're +going to want to think about as we kind + + align:start position:0% +going to want to think about as we kind + + + align:start position:0% +going to want to think about as we kind +of move from Theory to thinking about + + align:start position:0% +of move from Theory to thinking about + + + align:start position:0% +of move from Theory to thinking about +design is boy how how you know if I'm + + align:start position:0% +design is boy how how you know if I'm + + + align:start position:0% +design is boy how how you know if I'm +going to do things one way or another + + align:start position:0% +going to do things one way or another + + + align:start position:0% +going to do things one way or another +how can I get away with you know smaller + + align:start position:0% +how can I get away with you know smaller + + + align:start position:0% +how can I get away with you know smaller +voltage and current switches and and + + align:start position:0% +voltage and current switches and and + + + align:start position:0% +voltage and current switches and and +less energy storage in my passive + + align:start position:0% +less energy storage in my passive + + + align:start position:0% +less energy storage in my passive +components and some ways of doing things + + align:start position:0% +components and some ways of doing things + + + align:start position:0% +components and some ways of doing things +are going to be much better than others + + align:start position:0% +are going to be much better than others + + + align:start position:0% +are going to be much better than others +okay and that's part of the art of + + align:start position:0% +okay and that's part of the art of + + + align:start position:0% +okay and that's part of the art of +design is figuring out well gez what do + + align:start position:0% +design is figuring out well gez what do + + + align:start position:0% +design is figuring out well gez what do +I need to do and how is that going to + + align:start position:0% +I need to do and how is that going to + + + align:start position:0% +I need to do and how is that going to +translate into the size and loss and + + align:start position:0% +translate into the size and loss and + + + align:start position:0% +translate into the size and loss and +weight of the thing I'm designing okay + + align:start position:0% +weight of the thing I'm designing okay + + + align:start position:0% +weight of the thing I'm designing okay +and I want to take some initial steps + + align:start position:0% +and I want to take some initial steps + + + align:start position:0% +and I want to take some initial steps +today towards thinking about how we + + align:start position:0% +today towards thinking about how we + + + align:start position:0% +today towards thinking about how we +might do that + + align:start position:0% +might do that + + + align:start position:0% +might do that +okay and one of the things we're going + + align:start position:0% +okay and one of the things we're going + + + align:start position:0% +okay and one of the things we're going +to have to do in order to do that is + + align:start position:0% +to have to do in order to do that is + + + align:start position:0% +to have to do in order to do that is +we're going to have to throw out this + + align:start position:0% +we're going to have to throw out this + + + align:start position:0% +we're going to have to throw out this +assumption right it's you know for + + align:start position:0% +assumption right it's you know for + + + align:start position:0% +assumption right it's you know for +purposes of figuring out my conversion + + align:start position:0% +purposes of figuring out my conversion + + + align:start position:0% +purposes of figuring out my conversion +ratio and those kind of things you know + + align:start position:0% +ratio and those kind of things you know + + + align:start position:0% +ratio and those kind of things you know +I can imagine that my inductors and + + align:start position:0% +I can imagine that my inductors and + + + align:start position:0% +I can imagine that my inductors and +capacitors are really big that's a + + align:start position:0% +capacitors are really big that's a + + + align:start position:0% +capacitors are really big that's a +perfectly valid thing to do and we do it + + align:start position:0% +perfectly valid thing to do and we do it + + + align:start position:0% +perfectly valid thing to do and we do it +all the time but if I'm going to go + + align:start position:0% +all the time but if I'm going to go + + + align:start position:0% +all the time but if I'm going to go +build this thing you know + + align:start position:0% +build this thing you know + + + align:start position:0% +build this thing you know +first of all I can't go out and buy a + + align:start position:0% +first of all I can't go out and buy a + + + align:start position:0% +first of all I can't go out and buy a +one Henry inductor very easily and the + + align:start position:0% +one Henry inductor very easily and the + + + align:start position:0% +one Henry inductor very easily and the +bigger the inductance I buy what we're + + align:start position:0% +bigger the inductance I buy what we're + + + align:start position:0% +bigger the inductance I buy what we're +going to see is the more energy it has + + align:start position:0% +going to see is the more energy it has + + + align:start position:0% +going to see is the more energy it has +to store and the bigger it is and the + + align:start position:0% +to store and the bigger it is and the + + + align:start position:0% +to store and the bigger it is and the +losser is and everything else right so I + + align:start position:0% +losser is and everything else right so I + + + align:start position:0% +losser is and everything else right so I +need to start figuring out well how big + + align:start position:0% +need to start figuring out well how big + + + align:start position:0% +need to start figuring out well how big +does lnc have to be in order to achieve + + align:start position:0% +does lnc have to be in order to achieve + + + align:start position:0% +does lnc have to be in order to achieve +my goals okay and that's what I'd like + + align:start position:0% +my goals okay and that's what I'd like + + + align:start position:0% +my goals okay and that's what I'd like +to talk about today and the first thing + + align:start position:0% +to talk about today and the first thing + + + align:start position:0% +to talk about today and the first thing +we got to do is figure out what is the + + align:start position:0% +we got to do is figure out what is the + + + align:start position:0% +we got to do is figure out what is the +what is the impact of a finite + + align:start position:0% +what is the impact of a finite + + + align:start position:0% +what is the impact of a finite +component values on the converter + + align:start position:0% +component values on the converter + + + align:start position:0% +component values on the converter +okay and what we're going to see is + + align:start position:0% +okay and what we're going to see is + + + align:start position:0% +okay and what we're going to see is +there's a few things that might you know + + align:start position:0% +there's a few things that might you know + + + align:start position:0% +there's a few things that might you know +I one one of the things I have to do is + + align:start position:0% +I one one of the things I have to do is + + + align:start position:0% +I one one of the things I have to do is +figure out in any of these converters + + align:start position:0% +figure out in any of these converters + + + align:start position:0% +figure out in any of these converters +what value of L do I pick what value of + + align:start position:0% +what value of L do I pick what value of + + + align:start position:0% +what value of L do I pick what value of +C do I pick how I figure those out + + align:start position:0% +C do I pick how I figure those out + + + align:start position:0% +C do I pick how I figure those out +depends upon a few things okay um things + + align:start position:0% +depends upon a few things okay um things + + + align:start position:0% +depends upon a few things okay um things +that might determine that first of all + + align:start position:0% +that might determine that first of all + + + align:start position:0% +that might determine that first of all +is + + align:start position:0% +is + + + align:start position:0% +is +Ripple right how much voltage and + + align:start position:0% +Ripple right how much voltage and + + + align:start position:0% +Ripple right how much voltage and +current Ripple are permissible in the + + align:start position:0% +current Ripple are permissible in the + + + align:start position:0% +current Ripple are permissible in the +circuit and we're going to focus on + + align:start position:0% +circuit and we're going to focus on + + + align:start position:0% +circuit and we're going to focus on +Ripple today there's also the question + + align:start position:0% +Ripple today there's also the question + + + align:start position:0% +Ripple today there's also the question +of um transient Dynamics we'll look at + + align:start position:0% +of um transient Dynamics we'll look at + + + align:start position:0% +of um transient Dynamics we'll look at +that a little bit later in the term and + + align:start position:0% +that a little bit later in the term and + + + align:start position:0% +that a little bit later in the term and +that can also impact the decisions you + + align:start position:0% +that can also impact the decisions you + + + align:start position:0% +that can also impact the decisions you +make but it's sort of you know Ripple + + align:start position:0% +make but it's sort of you know Ripple + + + align:start position:0% +make but it's sort of you know Ripple +first transient Dynamic second and the + + align:start position:0% +first transient Dynamic second and the + + + align:start position:0% +first transient Dynamic second and the +other thing that's going to is going to + + align:start position:0% +other thing that's going to is going to + + + align:start position:0% +other thing that's going to is going to +come into the play is sort of how big + + align:start position:0% +come into the play is sort of how big + + + align:start position:0% +come into the play is sort of how big +and lossy and expensive are the + + align:start position:0% +and lossy and expensive are the + + + align:start position:0% +and lossy and expensive are the +components okay and we'll touch on that + + align:start position:0% +components okay and we'll touch on that + + + align:start position:0% +components okay and we'll touch on that +today a little bit we'll at least get a + + align:start position:0% +today a little bit we'll at least get a + + + align:start position:0% +today a little bit we'll at least get a +sort of a rough measure of how that goes + + align:start position:0% +sort of a rough measure of how that goes + + + align:start position:0% +sort of a rough measure of how that goes +okay so let's start to think about + + align:start position:0% +okay so let's start to think about + + + align:start position:0% +okay so let's start to think about +um how we might uh + + align:start position:0% +um how we might uh + + + align:start position:0% +um how we might uh +start calc sizing components in order + + align:start position:0% +start calc sizing components in order + + + align:start position:0% +start calc sizing components in order +that we need to figure out a way to + + align:start position:0% +that we need to figure out a way to + + + align:start position:0% +that we need to figure out a way to +calculate Ripple in the components okay + + align:start position:0% +calculate Ripple in the components okay + + + align:start position:0% +calculate Ripple in the components okay +so here's the game we're going to play + + align:start position:0% +so here's the game we're going to play + + + align:start position:0% +so here's the game we're going to play +let's think about the Boost converter + + align:start position:0% +let's think about the Boost converter + + + align:start position:0% +let's think about the Boost converter +for example + + align:start position:0% +for example + + + align:start position:0% +for example +okay so here's my Boost converter + + align:start position:0% + + + + align:start position:0% + +and I'm going to worry about what + + align:start position:0% +and I'm going to worry about what + + + align:start position:0% +and I'm going to worry about what +the Ripple for example on the capacitor + + align:start position:0% +the Ripple for example on the capacitor + + + align:start position:0% +the Ripple for example on the capacitor +voltage is and I'm also going to about + + align:start position:0% +voltage is and I'm also going to about + + + align:start position:0% +voltage is and I'm also going to about +worry about what the Ripple in the + + align:start position:0% +worry about what the Ripple in the + + + align:start position:0% +worry about what the Ripple in the +inductor current is + + align:start position:0% +inductor current is + + + align:start position:0% +inductor current is +okay I you know if I make an lnc really + + align:start position:0% +okay I you know if I make an lnc really + + + align:start position:0% +okay I you know if I make an lnc really +big then the Ripple goes to zero but I + + align:start position:0% +big then the Ripple goes to zero but I + + + align:start position:0% +big then the Ripple goes to zero but I +can't afford to make them too big + + align:start position:0% +can't afford to make them too big + + + align:start position:0% +can't afford to make them too big +because the components will be too big + + align:start position:0% +because the components will be too big + + + align:start position:0% +because the components will be too big +and too lossy okay so what does this + + align:start position:0% +and too lossy okay so what does this + + + align:start position:0% +and too lossy okay so what does this +look + + align:start position:0% +look + + + align:start position:0% +look +like um Let me let me plot for a + + align:start position:0% +like um Let me let me plot for a + + + align:start position:0% +like um Let me let me plot for a +second what id would look + + align:start position:0% +second what id would look + + + align:start position:0% +second what id would look +like + + align:start position:0% +like + + + align:start position:0% +like +and what what do I mean by ID let's look + + align:start position:0% +and what what do I mean by ID let's look + + + align:start position:0% +and what what do I mean by ID let's look +at + + align:start position:0% +at + + + align:start position:0% +at +this + + align:start position:0% + + + + align:start position:0% + +current + + align:start position:0% +current + + + align:start position:0% +current +okay why because that's going to be a + + align:start position:0% +okay why because that's going to be a + + + align:start position:0% +okay why because that's going to be a +key to figuring + + align:start position:0% +key to figuring + + + align:start position:0% +key to figuring +out how much Ripple I end up on the + + align:start position:0% +out how much Ripple I end up on the + + + align:start position:0% +out how much Ripple I end up on the +capacitor voltage so what happens in + + align:start position:0% +capacitor voltage so what happens in + + + align:start position:0% +capacitor voltage so what happens in +this converter in the first part of the + + align:start position:0% +this converter in the first part of the + + + align:start position:0% +this converter in the first part of the +cycle Q of T is high and the switch is + + align:start position:0% +cycle Q of T is high and the switch is + + + align:start position:0% +cycle Q of T is high and the switch is +on and ID is + + align:start position:0% +on and ID is + + + align:start position:0% +on and ID is +zero + + align:start position:0% +zero + + + align:start position:0% +zero +okay and in the second part of the cycle + + align:start position:0% +okay and in the second part of the cycle + + + align:start position:0% +okay and in the second part of the cycle +so that goes on for sometime DT + + align:start position:0% + + + + align:start position:0% + +okay and in the second part of the cycle + + align:start position:0% +okay and in the second part of the cycle + + + align:start position:0% +okay and in the second part of the cycle +the output goes to + + align:start position:0% +the output goes to + + + align:start position:0% +the output goes to +V2 right so uh I'm + + align:start position:0% +V2 right so uh I'm + + + align:start position:0% +V2 right so uh I'm +sorry in the first part of the cycle ID + + align:start position:0% +sorry in the first part of the cycle ID + + + align:start position:0% +sorry in the first part of the cycle ID +is zero because I is going through + + align:start position:0% +is zero because I is going through + + + align:start position:0% +is zero because I is going through +um is going through the switch in the + + align:start position:0% +um is going through the switch in the + + + align:start position:0% +um is going through the switch in the +second part of the cycle ID is equal to + + align:start position:0% +second part of the cycle ID is equal to + + + align:start position:0% +second part of the cycle ID is equal to +I right so this I'm just going to call I + + align:start position:0% +I right so this I'm just going to call I + + + align:start position:0% +I right so this I'm just going to call I +capital I okay now now I'm kind of + + align:start position:0% +capital I okay now now I'm kind of + + + align:start position:0% +capital I okay now now I'm kind of +assuming the L is really really big here + + align:start position:0% +assuming the L is really really big here + + + align:start position:0% +assuming the L is really really big here +I'm going to ignore the Ripple current + + align:start position:0% +I'm going to ignore the Ripple current + + + align:start position:0% +I'm going to ignore the Ripple current +in the + + align:start position:0% +in the + + + align:start position:0% +in the +inductor in order to calculate the + + align:start position:0% +inductor in order to calculate the + + + align:start position:0% +inductor in order to calculate the +Ripple voltage on the + + align:start position:0% +Ripple voltage on the + + + align:start position:0% +Ripple voltage on the +capacitor all right and it turns out you + + align:start position:0% +capacitor all right and it turns out you + + + align:start position:0% +capacitor all right and it turns out you +can do that freely and you'll still get + + align:start position:0% +can do that freely and you'll still get + + + align:start position:0% +can do that freely and you'll still get +the right answer okay and I'll show you + + align:start position:0% +the right answer okay and I'll show you + + + align:start position:0% +the right answer okay and I'll show you +that in a moment + + align:start position:0% +that in a moment + + + align:start position:0% +that in a moment +okay but this is what id looks + + align:start position:0% +okay but this is what id looks + + + align:start position:0% +okay but this is what id looks +like okay so here's T and this is + + align:start position:0% +like okay so here's T and this is + + + align:start position:0% +like okay so here's T and this is +ID okay + + align:start position:0% +ID okay + + + align:start position:0% +ID okay +okay + + align:start position:0% +okay + + + align:start position:0% +okay +well what's ID's average + + align:start position:0% +well what's ID's average + + + align:start position:0% +well what's ID's average +value right if I were to calculate the + + align:start position:0% +value right if I were to calculate the + + + align:start position:0% +value right if I were to calculate the +average value of the diode current + + align:start position:0% +average value of the diode current + + + align:start position:0% +average value of the diode current +ID that would simply be the average of + + align:start position:0% +ID that would simply be the average of + + + align:start position:0% +ID that would simply be the average of +this pulse waveform which is basically + + align:start position:0% +this pulse waveform which is basically + + + align:start position:0% +this pulse waveform which is basically +um 1 minus D * + + align:start position:0% + + + + align:start position:0% + +I + + align:start position:0% +I + + + align:start position:0% +I +okay so maybe what I would do is say + + align:start position:0% +okay so maybe what I would do is say + + + align:start position:0% +okay so maybe what I would do is say +okay let me come up with a model for + + align:start position:0% +okay let me come up with a model for + + + align:start position:0% +okay let me come up with a model for +this converter that I don't really care + + align:start position:0% +this converter that I don't really care + + + align:start position:0% +this converter that I don't really care +about what's going on over here right in + + align:start position:0% +about what's going on over here right in + + + align:start position:0% +about what's going on over here right in +terms of figuring out the capacitor + + align:start position:0% +terms of figuring out the capacitor + + + align:start position:0% +terms of figuring out the capacitor +voltage Ripple all I care is about what + + align:start position:0% +voltage Ripple all I care is about what + + + align:start position:0% +voltage Ripple all I care is about what +current's coming through the diode and + + align:start position:0% +current's coming through the diode and + + + align:start position:0% +current's coming through the diode and +driving this output circuit okay so I + + align:start position:0% +driving this output circuit okay so I + + + align:start position:0% +driving this output circuit okay so I +might model this this + + align:start position:0% +might model this this + + + align:start position:0% +might model this this +way model this as some Ripple current + + align:start position:0% +way model this as some Ripple current + + + align:start position:0% +way model this as some Ripple current +ID okay that is then going + + align:start position:0% +ID okay that is then going + + + align:start position:0% +ID okay that is then going +into my capacitor + + align:start position:0% + + + + align:start position:0% + +VC and my load + + align:start position:0% + + + + align:start position:0% + +resistor okay any questions about + + align:start position:0% + + + + align:start position:0% + +that now if I design this + + align:start position:0% +that now if I design this + + + align:start position:0% +that now if I design this +circuit I'm interested in the Ripple on + + align:start position:0% +circuit I'm interested in the Ripple on + + + align:start position:0% +circuit I'm interested in the Ripple on +the capacitor and what I'm likely to do + + align:start position:0% +the capacitor and what I'm likely to do + + + align:start position:0% +the capacitor and what I'm likely to do +is put the switching frequency you know + + align:start position:0% +is put the switching frequency you know + + + align:start position:0% +is put the switching frequency you know +T is equal to one over this is equal to + + align:start position:0% +T is equal to one over this is equal to + + + align:start position:0% +T is equal to one over this is equal to +one over the switching frequency right + + align:start position:0% +one over the switching frequency right + + + align:start position:0% +one over the switching frequency right +what I'm likely to do is to make this RC + + align:start position:0% +what I'm likely to do is to make this RC + + + align:start position:0% +what I'm likely to do is to make this RC +such that it filters that Ripple current + + align:start position:0% +such that it filters that Ripple current + + + align:start position:0% +such that it filters that Ripple current +right I've got this pulsating current in + + align:start position:0% +right I've got this pulsating current in + + + align:start position:0% +right I've got this pulsating current in +and what I really want is VC to be + + align:start position:0% +and what I really want is VC to be + + + align:start position:0% +and what I really want is VC to be +almost constant and hence the V2 is + + align:start position:0% +almost constant and hence the V2 is + + + align:start position:0% +almost constant and hence the V2 is +almost constant right so that means that + + align:start position:0% +almost constant right so that means that + + + align:start position:0% +almost constant right so that means that +the the sort of the AC component of this + + align:start position:0% +the the sort of the AC component of this + + + align:start position:0% +the the sort of the AC component of this +pulsating waveform we really want to go + + align:start position:0% +pulsating waveform we really want to go + + + align:start position:0% +pulsating waveform we really want to go +through the capacitor almost + + align:start position:0% +through the capacitor almost + + + align:start position:0% +through the capacitor almost +exclusively and you know the DC + + align:start position:0% +exclusively and you know the DC + + + align:start position:0% +exclusively and you know the DC +component of this current 1 minus D is + + align:start position:0% +component of this current 1 minus D is + + + align:start position:0% +component of this current 1 minus D is +what goes to to the output right well + + align:start position:0% +what goes to to the output right well + + + align:start position:0% +what goes to to the output right well +what do I need to make that happen what + + align:start position:0% +what do I need to make that happen what + + + align:start position:0% +what do I need to make that happen what +I need is uh 2 pi F + + align:start position:0% +I need is uh 2 pi F + + + align:start position:0% +I need is uh 2 pi F +switch ought to be much greater than + + align:start position:0% +switch ought to be much greater than + + + align:start position:0% +switch ought to be much greater than +one/ + + align:start position:0% +one/ + + + align:start position:0% +one/ +RC right so that this RC network filters + + align:start position:0% +RC right so that this RC network filters + + + align:start position:0% +RC right so that this RC network filters +the pulsating component of this current + + align:start position:0% +the pulsating component of this current + + + align:start position:0% +the pulsating component of this current +and so that gets the DC current going + + align:start position:0% +and so that gets the DC current going + + + align:start position:0% +and so that gets the DC current going +this way and the Ripple current going + + align:start position:0% +this way and the Ripple current going + + + align:start position:0% +this way and the Ripple current going +this way okay any questions about + + align:start position:0% + + + + align:start position:0% + +that how did you get that + + align:start position:0% +that how did you get that + + + align:start position:0% +that how did you get that +RC uh okay so the the time constant of + + align:start position:0% +RC uh okay so the the time constant of + + + align:start position:0% +RC uh okay so the the time constant of +this is RC that means it's pole is it + + align:start position:0% +this is RC that means it's pole is it + + + align:start position:0% +this is RC that means it's pole is it +Min is it s is equal to minus one/ + + align:start position:0% +Min is it s is equal to minus one/ + + + align:start position:0% +Min is it s is equal to minus one/ +RC and so I'm + + align:start position:0% +RC and so I'm + + + align:start position:0% +RC and so I'm +putting the switching frequency the + + align:start position:0% +putting the switching frequency the + + + align:start position:0% +putting the switching frequency the +Ripple frequency far beyond that so that + + align:start position:0% +Ripple frequency far beyond that so that + + + align:start position:0% +Ripple frequency far beyond that so that +this becomes essentially a low pass + + align:start position:0% +this becomes essentially a low pass + + + align:start position:0% +this becomes essentially a low pass +filter so I'm putting it well beyond the + + align:start position:0% +filter so I'm putting it well beyond the + + + align:start position:0% +filter so I'm putting it well beyond the +cut + + align:start position:0% + + + + align:start position:0% + +off okay okay so suppose I do + + align:start position:0% +off okay okay so suppose I do + + + align:start position:0% +off okay okay so suppose I do +that okay um maybe what I should be + + align:start position:0% +that okay um maybe what I should be + + + align:start position:0% +that okay um maybe what I should be +thinking about is if I can make the + + align:start position:0% +thinking about is if I can make the + + + align:start position:0% +thinking about is if I can make the +approximation that all the Ripple + + align:start position:0% +approximation that all the Ripple + + + align:start position:0% +approximation that all the Ripple +current is going to the capacitor and + + align:start position:0% +current is going to the capacitor and + + + align:start position:0% +current is going to the capacitor and +all the DC currents going to the + + align:start position:0% +all the DC currents going to the + + + align:start position:0% +all the DC currents going to the +resistor and I only want to focus on the + + align:start position:0% +resistor and I only want to focus on the + + + align:start position:0% +resistor and I only want to focus on the +Ripple why don't I think about with the + + align:start position:0% +Ripple why don't I think about with the + + + align:start position:0% +Ripple why don't I think about with the +Ripple current let me make an AC model + + align:start position:0% +Ripple current let me make an AC model + + + align:start position:0% +Ripple current let me make an AC model +for this thing and just subtract off the + + align:start position:0% +for this thing and just subtract off the + + + align:start position:0% +for this thing and just subtract off the +DC component okay I know none of the + + align:start position:0% +DC component okay I know none of the + + + align:start position:0% +DC component okay I know none of the +Ripple I know none of the DC currents + + align:start position:0% +Ripple I know none of the DC currents + + + align:start position:0% +Ripple I know none of the DC currents +going into the capacitor right we we + + align:start position:0% +going into the capacitor right we we + + + align:start position:0% +going into the capacitor right we we +sort of know that from the fact of + + align:start position:0% +sort of know that from the fact of + + + align:start position:0% +sort of know that from the fact of +periodic steady state okay so maybe what + + align:start position:0% +periodic steady state okay so maybe what + + + align:start position:0% +periodic steady state okay so maybe what +I could do is make a new + + align:start position:0% +I could do is make a new + + + align:start position:0% +I could do is make a new +model that I'm going to call ID + + align:start position:0% + + + + align:start position:0% + +Tilda which is exactly which is exactly + + align:start position:0% +Tilda which is exactly which is exactly + + + align:start position:0% +Tilda which is exactly which is exactly +just the AC component of this waveform + + align:start position:0% +just the AC component of this waveform + + + align:start position:0% +just the AC component of this waveform +ID okay so I'm going to subtract off the + + align:start position:0% +ID okay so I'm going to subtract off the + + + align:start position:0% +ID okay so I'm going to subtract off the +DC value and just keep the AC value + + align:start position:0% +DC value and just keep the AC value + + + align:start position:0% +DC value and just keep the AC value +what's that going to be well in the + + align:start position:0% +what's that going to be well in the + + + align:start position:0% +what's that going to be well in the +first part of the cycle it's going to be + + align:start position:0% +first part of the cycle it's going to be + + + align:start position:0% +first part of the cycle it's going to be +zero - 1 - D iil so this will be + + align:start position:0% +zero - 1 - D iil so this will be + + + align:start position:0% +zero - 1 - D iil so this will be +minus 1 - D + + align:start position:0% +minus 1 - D + + + align:start position:0% +minus 1 - D +iil okay in the first part of the cycle + + align:start position:0% +iil okay in the first part of the cycle + + + align:start position:0% +iil okay in the first part of the cycle +in the second part of the + + align:start position:0% +in the second part of the + + + align:start position:0% +in the second part of the +cycle it would be ID minus one minus D + + align:start position:0% +cycle it would be ID minus one minus D + + + align:start position:0% +cycle it would be ID minus one minus D +which would make it + + align:start position:0% +which would make it + + + align:start position:0% +which would make it +D + + align:start position:0% +D + + + align:start position:0% +D +okay like + + align:start position:0% + + + + align:start position:0% + +this right and this is DT this is T okay + + align:start position:0% +this right and this is DT this is T okay + + + align:start position:0% +this right and this is DT this is T okay +so this is the AC component of the + + align:start position:0% +so this is the AC component of the + + + align:start position:0% +so this is the AC component of the +Ripple current coming through the diode + + align:start position:0% +Ripple current coming through the diode + + + align:start position:0% +Ripple current coming through the diode +so here we + + align:start position:0% + + + + align:start position:0% + +have ID + + align:start position:0% +have ID + + + align:start position:0% +have ID +Tilda okay and where that's really going + + align:start position:0% +Tilda okay and where that's really going + + + align:start position:0% +Tilda okay and where that's really going +is is all going into the + + align:start position:0% +is is all going into the + + + align:start position:0% +is is all going into the +capacitor right that's my approximation + + align:start position:0% +capacitor right that's my approximation + + + align:start position:0% +capacitor right that's my approximation +all the Ripple current goes into the + + align:start position:0% +all the Ripple current goes into the + + + align:start position:0% +all the Ripple current goes into the +capacitor okay um if I make this + + align:start position:0% +capacitor okay um if I make this + + + align:start position:0% +capacitor okay um if I make this +approximation then I ought to be able to + + align:start position:0% +approximation then I ought to be able to + + + align:start position:0% +approximation then I ought to be able to +calculate the the Ripple voltage on the + + align:start position:0% +calculate the the Ripple voltage on the + + + align:start position:0% +calculate the the Ripple voltage on the +capacitor VC + + align:start position:0% + + + + align:start position:0% + +Tilda does that make + + align:start position:0% + + + + align:start position:0% + +sense so what should + + align:start position:0% +sense so what should + + + align:start position:0% +sense so what should +happen well if I have + + align:start position:0% + + + + align:start position:0% + +um in the first part of the cycle right + + align:start position:0% +um in the first part of the cycle right + + + align:start position:0% +um in the first part of the cycle right +here's VC tlda + + align:start position:0% + + + + align:start position:0% + +okay in the first part of the + + align:start position:0% +okay in the first part of the + + + align:start position:0% +okay in the first part of the +cycle I've got a negative constant + + align:start position:0% +cycle I've got a negative constant + + + align:start position:0% +cycle I've got a negative constant +current through the + + align:start position:0% +current through the + + + align:start position:0% +current through the +capacitor right so basically the + + align:start position:0% +capacitor right so basically the + + + align:start position:0% +capacitor right so basically the +capacitor voltage ought to be falling in + + align:start position:0% +capacitor voltage ought to be falling in + + + align:start position:0% +capacitor voltage ought to be falling in +the first part of the cycle + + align:start position:0% +the first part of the cycle + + + align:start position:0% +the first part of the cycle +linearly + + align:start position:0% +linearly + + + align:start position:0% +linearly +okay for + + align:start position:0% +okay for + + + align:start position:0% +okay for +DT and then should be rising in the + + align:start position:0% +DT and then should be rising in the + + + align:start position:0% +DT and then should be rising in the +second part of the cycle for + + align:start position:0% +second part of the cycle for + + + align:start position:0% +second part of the cycle for +DT okay + + align:start position:0% + + + + align:start position:0% + +this is what the Ripple current this is + + align:start position:0% +this is what the Ripple current this is + + + align:start position:0% +this is what the Ripple current this is +what the Ripple voltage VC Tilda is + + align:start position:0% +what the Ripple voltage VC Tilda is + + + align:start position:0% +what the Ripple voltage VC Tilda is +going to look + + align:start position:0% + + + + align:start position:0% + +like all right under my + + align:start position:0% +like all right under my + + + align:start position:0% +like all right under my +approximation all right well what does + + align:start position:0% +approximation all right well what does + + + align:start position:0% +approximation all right well what does +that mean well it turns out that if I + + align:start position:0% +that mean well it turns out that if I + + + align:start position:0% +that mean well it turns out that if I +have a triangle wave its midpoint is + + align:start position:0% +have a triangle wave its midpoint is + + + align:start position:0% +have a triangle wave its midpoint is +halfway between the two extremes so this + + align:start position:0% +halfway between the two extremes so this + + + align:start position:0% +halfway between the two extremes so this +I might + + align:start position:0% +I might + + + align:start position:0% +I might +call Delta VC P to Peak and it turns out + + align:start position:0% +call Delta VC P to Peak and it turns out + + + align:start position:0% +call Delta VC P to Peak and it turns out +what that means is this will be Delta VC + + align:start position:0% +what that means is this will be Delta VC + + + align:start position:0% +what that means is this will be Delta VC +Peak to Peak over two and this will be + + align:start position:0% +Peak to Peak over two and this will be + + + align:start position:0% +Peak to Peak over two and this will be +Delta VC Peak to Peak over two okay well + + align:start position:0% +Delta VC Peak to Peak over two okay well + + + align:start position:0% +Delta VC Peak to Peak over two okay well +what is this value and I should have + + align:start position:0% +what is this value and I should have + + + align:start position:0% +what is this value and I should have +said this is DT and this is + + align:start position:0% +said this is DT and this is + + + align:start position:0% +said this is DT and this is +T all + + align:start position:0% +T all + + + align:start position:0% +T all +right IC is equal to C DVC + + align:start position:0% +right IC is equal to C DVC + + + align:start position:0% +right IC is equal to C DVC +DT right Delta VC Peak to Peak ought to + + align:start position:0% +DT right Delta VC Peak to Peak ought to + + + align:start position:0% +DT right Delta VC Peak to Peak ought to +be equal to 1 / C the + + align:start position:0% +be equal to 1 / C the + + + align:start position:0% +be equal to 1 / C the +integral uh I could do it um from here + + align:start position:0% +integral uh I could do it um from here + + + align:start position:0% +integral uh I could do it um from here +to Here For + + align:start position:0% +to Here For + + + align:start position:0% +to Here For +example of uh between DT and T of + + align:start position:0% + + + + align:start position:0% + +icdt which works out to be what that's 1 + + align:start position:0% +icdt which works out to be what that's 1 + + + align:start position:0% +icdt which works out to be what that's 1 +/ C the current is constant at Dil + + align:start position:0% + + + + align:start position:0% + +and that happens for um a Time 1 minus + + align:start position:0% + + + + align:start position:0% + +DT right so this is Delta VC Peak to + + align:start position:0% + + + + align:start position:0% + +Peak does everybody buy + + align:start position:0% + + + + align:start position:0% + +that so what can I say + + align:start position:0% + + + + align:start position:0% + +then the capacitor Ripple voltage under + + align:start position:0% +then the capacitor Ripple voltage under + + + align:start position:0% +then the capacitor Ripple voltage under +these approximations + + align:start position:0% +these approximations + + + align:start position:0% +these approximations +is inversely proportional to the + + align:start position:0% +is inversely proportional to the + + + align:start position:0% +is inversely proportional to the +capacitor value right so if I were to + + align:start position:0% +capacitor value right so if I were to + + + align:start position:0% +capacitor value right so if I were to +come up to you and say you know what I'm + + align:start position:0% +come up to you and say you know what I'm + + + align:start position:0% +come up to you and say you know what I'm +only going to allow you know 100 molts + + align:start position:0% +only going to allow you know 100 molts + + + align:start position:0% +only going to allow you know 100 molts +of Ripple in my + + align:start position:0% +of Ripple in my + + + align:start position:0% +of Ripple in my +output or some value other value of + + align:start position:0% +output or some value other value of + + + align:start position:0% +output or some value other value of +delta VC Peak to Peak this equation + + align:start position:0% +delta VC Peak to Peak this equation + + + align:start position:0% +delta VC Peak to Peak this equation +tells me what that should be right this + + align:start position:0% +tells me what that should be right this + + + align:start position:0% +tells me what that should be right this +just says basically C has to be greater + + align:start position:0% +just says basically C has to be greater + + + align:start position:0% +just says basically C has to be greater +than or equal to um D * 1 minus + + align:start position:0% +than or equal to um D * 1 minus + + + align:start position:0% +than or equal to um D * 1 minus +d + + align:start position:0% +d + + + align:start position:0% +d +i t over Delta v c Peak to Peak + + align:start position:0% +i t over Delta v c Peak to Peak + + + align:start position:0% +i t over Delta v c Peak to Peak +right so if I if you tell me okay what's + + align:start position:0% +right so if I if you tell me okay what's + + + align:start position:0% +right so if I if you tell me okay what's +my load current and my switching period + + align:start position:0% +my load current and my switching period + + + align:start position:0% +my load current and my switching period +my duty ratio this tells me how big does + + align:start position:0% +my duty ratio this tells me how big does + + + align:start position:0% +my duty ratio this tells me how big does +the capacitor have to be in order to + + align:start position:0% +the capacitor have to be in order to + + + align:start position:0% +the capacitor have to be in order to +reduce the output Ripple down to an + + align:start position:0% +reduce the output Ripple down to an + + + align:start position:0% +reduce the output Ripple down to an +acceptable value that I + + align:start position:0% +acceptable value that I + + + align:start position:0% +acceptable value that I +set okay any questions on that + + align:start position:0% + + + + align:start position:0% + +now it turns out that I could do the + + align:start position:0% +now it turns out that I could do the + + + align:start position:0% +now it turns out that I could do the +same kind of + + align:start position:0% +same kind of + + + align:start position:0% +same kind of +calculation for the inductor current + + align:start position:0% +calculation for the inductor current + + + align:start position:0% +calculation for the inductor current +Ripple all right and I should say by the + + align:start position:0% +Ripple all right and I should say by the + + + align:start position:0% +Ripple all right and I should say by the +way that in a typical converter I + + align:start position:0% +way that in a typical converter I + + + align:start position:0% +way that in a typical converter I +usually am not allowing very much + + align:start position:0% +usually am not allowing very much + + + align:start position:0% +usually am not allowing very much +capacitor voltage Ripple right if I want + + align:start position:0% +capacitor voltage Ripple right if I want + + + align:start position:0% +capacitor voltage Ripple right if I want +a DCd converter you know this has to be + + align:start position:0% +a DCd converter you know this has to be + + + align:start position:0% +a DCd converter you know this has to be +small and we'll come into what we mean + + align:start position:0% +small and we'll come into what we mean + + + align:start position:0% +small and we'll come into what we mean +by how small is small okay inductor + + align:start position:0% +by how small is small okay inductor + + + align:start position:0% +by how small is small okay inductor +current Ripple maybe we can allow a bit + + align:start position:0% +current Ripple maybe we can allow a bit + + + align:start position:0% +current Ripple maybe we can allow a bit +more but we can do the same trick to + + align:start position:0% +more but we can do the same trick to + + + align:start position:0% +more but we can do the same trick to +calculate it right so if I were to come + + align:start position:0% +calculate it right so if I were to come + + + align:start position:0% +calculate it right so if I were to come +up here and say okay let me go through + + align:start position:0% +up here and say okay let me go through + + + align:start position:0% +up here and say okay let me go through +the same really quick + + align:start position:0% +the same really quick + + + align:start position:0% +the same really quick +procedure okay so here we go here's my + + align:start position:0% +procedure okay so here we go here's my + + + align:start position:0% +procedure okay so here we go here's my +uh converter and what I'm really going + + align:start position:0% +uh converter and what I'm really going + + + align:start position:0% +uh converter and what I'm really going +to think about now is uh what is this + + align:start position:0% +to think about now is uh what is this + + + align:start position:0% +to think about now is uh what is this +voltage suppose I Define this voltage um + + align:start position:0% + + + + align:start position:0% + +VX here + + align:start position:0% +VX here + + + align:start position:0% +VX here +okay I could come up with a model that + + align:start position:0% +okay I could come up with a model that + + + align:start position:0% +okay I could come up with a model that +looks like this I have uh + + align:start position:0% + + + + align:start position:0% + +V1 and then an + + align:start position:0% +V1 and then an + + + align:start position:0% +V1 and then an +inductor and then a voltage that I'll + + align:start position:0% +inductor and then a voltage that I'll + + + align:start position:0% +inductor and then a voltage that I'll +call a pulsating voltage that I'm going + + align:start position:0% +call a pulsating voltage that I'm going + + + align:start position:0% +call a pulsating voltage that I'm going +to call + + align:start position:0% + + + + align:start position:0% + +VX and what does VX look like VX looks + + align:start position:0% +VX and what does VX look like VX looks + + + align:start position:0% +VX and what does VX look like VX looks +like + + align:start position:0% +like + + + align:start position:0% +like +this in the first part of the cycle + + align:start position:0% + + + + align:start position:0% + +in the first part of the cycle when the + + align:start position:0% +in the first part of the cycle when the + + + align:start position:0% +in the first part of the cycle when the +switch is on VX is + + align:start position:0% +switch is on VX is + + + align:start position:0% +switch is on VX is +zero until sometime + + align:start position:0% +zero until sometime + + + align:start position:0% +zero until sometime +DT in the second part of the cycle um + + align:start position:0% +DT in the second part of the cycle um + + + align:start position:0% +DT in the second part of the cycle um +the switch is off and the diode is on + + align:start position:0% +the switch is off and the diode is on + + + align:start position:0% +the switch is off and the diode is on +and it's equal to VC which is the same + + align:start position:0% +and it's equal to VC which is the same + + + align:start position:0% +and it's equal to VC which is the same +as V2 right so here I go here's V + + align:start position:0% +as V2 right so here I go here's V + + + align:start position:0% +as V2 right so here I go here's V +Capital VC okay so the switch voltage + + align:start position:0% +Capital VC okay so the switch voltage + + + align:start position:0% +Capital VC okay so the switch voltage +I'm sorry the switch voltage comes up + + align:start position:0% +I'm sorry the switch voltage comes up + + + align:start position:0% +I'm sorry the switch voltage comes up +here okay + + align:start position:0% + + + + align:start position:0% + +and I could then say okay this is VX of + + align:start position:0% +and I could then say okay this is VX of + + + align:start position:0% +and I could then say okay this is VX of +T in my ripple model and the average + + align:start position:0% +T in my ripple model and the average + + + align:start position:0% +T in my ripple model and the average +voltage here which is the same thing as + + align:start position:0% +voltage here which is the same thing as + + + align:start position:0% +voltage here which is the same thing as +the average value of V1 is 1 minus D + + align:start position:0% +the average value of V1 is 1 minus D + + + align:start position:0% +the average value of V1 is 1 minus D +time + + align:start position:0% +time + + + align:start position:0% +time +VC right is the average voltage of this + + align:start position:0% +VC right is the average voltage of this + + + align:start position:0% +VC right is the average voltage of this +pulsating + + align:start position:0% +pulsating + + + align:start position:0% +pulsating +waveform okay I could then say all right + + align:start position:0% +waveform okay I could then say all right + + + align:start position:0% +waveform okay I could then say all right +this is what the circuit model looks + + align:start position:0% +this is what the circuit model looks + + + align:start position:0% +this is what the circuit model looks +like let me just consider its AC values + + align:start position:0% +like let me just consider its AC values + + + align:start position:0% +like let me just consider its AC values +right let me consider the Ripple current + + align:start position:0% +right let me consider the Ripple current + + + align:start position:0% +right let me consider the Ripple current +only in this thing so okay what happens + + align:start position:0% +only in this thing so okay what happens + + + align:start position:0% +only in this thing so okay what happens +what's the Ripple in capital V1 it's + + align:start position:0% +what's the Ripple in capital V1 it's + + + align:start position:0% +what's the Ripple in capital V1 it's +nothing right then I have my inductor + + align:start position:0% +nothing right then I have my inductor + + + align:start position:0% +nothing right then I have my inductor +and this is L with a current + + align:start position:0% + + + + align:start position:0% + +I right here's I this will be I Tilda + + align:start position:0% +I right here's I this will be I Tilda + + + align:start position:0% +I right here's I this will be I Tilda +the AC component only this thing I may + + align:start position:0% +the AC component only this thing I may + + + align:start position:0% +the AC component only this thing I may +have a ripple voltage looks like + + align:start position:0% +have a ripple voltage looks like + + + align:start position:0% +have a ripple voltage looks like +this in the first part of the cycle this + + align:start position:0% +this in the first part of the cycle this + + + align:start position:0% +this in the first part of the cycle this +is minus one minus + + align:start position:0% + + + + align:start position:0% + +d uh + + align:start position:0% + + + + align:start position:0% + +VC and the second part of the cycle it's + + align:start position:0% +VC and the second part of the cycle it's + + + align:start position:0% +VC and the second part of the cycle it's +VC minus one minus DVC which is + + align:start position:0% +VC minus one minus DVC which is + + + align:start position:0% +VC minus one minus DVC which is +DVC okay so this is what um VX Tilda + + align:start position:0% +DVC okay so this is what um VX Tilda + + + align:start position:0% +DVC okay so this is what um VX Tilda +looks + + align:start position:0% +looks + + + align:start position:0% +looks +like okay and here's vx to in my + + align:start position:0% + + + + align:start position:0% + +circuit all right and of course V + + align:start position:0% +circuit all right and of course V + + + align:start position:0% +circuit all right and of course V +subel is just minus VX + + align:start position:0% +subel is just minus VX + + + align:start position:0% +subel is just minus VX +TOA right so then I can I can figure out + + align:start position:0% +TOA right so then I can I can figure out + + + align:start position:0% +TOA right so then I can I can figure out +that okay + + align:start position:0% +that okay + + + align:start position:0% +that okay +um basically the negative of this + + align:start position:0% +um basically the negative of this + + + align:start position:0% +um basically the negative of this +voltage is the voltage on the + + align:start position:0% +voltage is the voltage on the + + + align:start position:0% +voltage is the voltage on the +inductor right so V subel is equal to + + align:start position:0% +inductor right so V subel is equal to + + + align:start position:0% +inductor right so V subel is equal to +ldt so Delta iil Peak to Peak is simply + + align:start position:0% +ldt so Delta iil Peak to Peak is simply + + + align:start position:0% +ldt so Delta iil Peak to Peak is simply +going to be + + align:start position:0% +going to be + + + align:start position:0% +going to be +um 1 over L the integral from 0 to DT of + + align:start position:0% +um 1 over L the integral from 0 to DT of + + + align:start position:0% +um 1 over L the integral from 0 to DT of +vbl DT okay and so what am I expecting + + align:start position:0% +vbl DT okay and so what am I expecting + + + align:start position:0% +vbl DT okay and so what am I expecting +I'm putting VX is negative constant + + align:start position:0% +I'm putting VX is negative constant + + + align:start position:0% +I'm putting VX is negative constant +voltage + + align:start position:0% +voltage + + + align:start position:0% +voltage +so that means VL is a positive constant + + align:start position:0% +so that means VL is a positive constant + + + align:start position:0% +so that means VL is a positive constant +voltage in the first part of the cycle + + align:start position:0% +voltage in the first part of the cycle + + + align:start position:0% +voltage in the first part of the cycle +and I should get a inductor Ripple + + align:start position:0% +and I should get a inductor Ripple + + + align:start position:0% +and I should get a inductor Ripple +current here that does + + align:start position:0% +current here that does + + + align:start position:0% +current here that does +this and then in the Nega second part of + + align:start position:0% +this and then in the Nega second part of + + + align:start position:0% +this and then in the Nega second part of +the cycle it does this so again the + + align:start position:0% +the cycle it does this so again the + + + align:start position:0% +the cycle it does this so again the +voltage the voltage Ripple I'm sorry the + + align:start position:0% +voltage the voltage Ripple I'm sorry the + + + align:start position:0% +voltage the voltage Ripple I'm sorry the +inductor current Ripple i l Tilda is + + align:start position:0% +inductor current Ripple i l Tilda is + + + align:start position:0% +inductor current Ripple i l Tilda is +going to be + + align:start position:0% +going to be + + + align:start position:0% +going to be +triangular and this + + align:start position:0% +triangular and this + + + align:start position:0% +triangular and this +amount + + align:start position:0% + + + + align:start position:0% + +here is going to be Delta i l Peak to + + align:start position:0% +here is going to be Delta i l Peak to + + + align:start position:0% +here is going to be Delta i l Peak to +Peak which I can calculate that as 1 + + align:start position:0% +Peak which I can calculate that as 1 + + + align:start position:0% +Peak which I can calculate that as 1 +over L this is going to be 1 minus + + align:start position:0% + + + + align:start position:0% + +DVC which goes on for a time period + + align:start position:0% + + + + align:start position:0% + +DT okay and what I get in the end is + + align:start position:0% +DT okay and what I get in the end is + + + align:start position:0% +DT okay and what I get in the end is +that uh L ought to be greater than or + + align:start position:0% +that uh L ought to be greater than or + + + align:start position:0% +that uh L ought to be greater than or +equal + + align:start position:0% +equal + + + align:start position:0% +equal +to 1us D + + align:start position:0% +to 1us D + + + align:start position:0% +to 1us D +time D time + + align:start position:0% +time D time + + + align:start position:0% +time D time +VC T over Delta I Peak to + + align:start position:0% +VC T over Delta I Peak to + + + align:start position:0% +VC T over Delta I Peak to +Peak right so if I have a limitation on + + align:start position:0% +Peak right so if I have a limitation on + + + align:start position:0% +Peak right so if I have a limitation on +the allowable Ripple current in the + + align:start position:0% +the allowable Ripple current in the + + + align:start position:0% +the allowable Ripple current in the +inductor I can calculate for a given + + align:start position:0% +inductor I can calculate for a given + + + align:start position:0% +inductor I can calculate for a given +operating condition how big that + + align:start position:0% +operating condition how big that + + + align:start position:0% +operating condition how big that +inductor needs to + + align:start position:0% +inductor needs to + + + align:start position:0% +inductor needs to +be and the only assumption I made was + + align:start position:0% +be and the only assumption I made was + + + align:start position:0% +be and the only assumption I made was +that I ignored the Ripple in + + align:start position:0% +that I ignored the Ripple in + + + align:start position:0% +that I ignored the Ripple in +V2 when I calculated this okay are there + + align:start position:0% +V2 when I calculated this okay are there + + + align:start position:0% +V2 when I calculated this okay are there +any questions about + + align:start position:0% + + + + align:start position:0% + +that now interesting I made some + + align:start position:0% +that now interesting I made some + + + align:start position:0% +that now interesting I made some +approximations right when I when I + + align:start position:0% +approximations right when I when I + + + align:start position:0% +approximations right when I when I +calculated the capacitor voltage Ripple + + align:start position:0% +calculated the capacitor voltage Ripple + + + align:start position:0% +calculated the capacitor voltage Ripple +I ignored the inductor current Ripple + + align:start position:0% +I ignored the inductor current Ripple + + + align:start position:0% +I ignored the inductor current Ripple +and when I calculated the inductor + + align:start position:0% +and when I calculated the inductor + + + align:start position:0% +and when I calculated the inductor +current Ripple I ignored the capacitor + + align:start position:0% +current Ripple I ignored the capacitor + + + align:start position:0% +current Ripple I ignored the capacitor +voltage Ripple doesn't matter that I did + + align:start position:0% +voltage Ripple doesn't matter that I did + + + align:start position:0% +voltage Ripple doesn't matter that I did +that the answer is no why + + align:start position:0% +that the answer is no why + + + align:start position:0% +that the answer is no why +because I pretended that that I was + + align:start position:0% +because I pretended that that I was + + + align:start position:0% +because I pretended that that I was +constant at a constant current when I + + align:start position:0% +constant at a constant current when I + + + align:start position:0% +constant at a constant current when I +calculated this waveform right well what + + align:start position:0% +calculated this waveform right well what + + + align:start position:0% +calculated this waveform right well what +does I look like + + align:start position:0% +does I look like + + + align:start position:0% +does I look like +iil has some Ripple in it and sort of + + align:start position:0% +iil has some Ripple in it and sort of + + + align:start position:0% +iil has some Ripple in it and sort of +this triangular Ripple falling the only + + align:start position:0% +this triangular Ripple falling the only + + + align:start position:0% +this triangular Ripple falling the only +thing that would have happened had I + + align:start position:0% +thing that would have happened had I + + + align:start position:0% +thing that would have happened had I +included that is that I would have had a + + align:start position:0% +included that is that I would have had a + + + align:start position:0% +included that is that I would have had a +little Ripple + + align:start position:0% +little Ripple + + + align:start position:0% +little Ripple +here okay and if I included that and + + align:start position:0% +here okay and if I included that and + + + align:start position:0% +here okay and if I included that and +then I calculated the voltage + + align:start position:0% +then I calculated the voltage + + + align:start position:0% +then I calculated the voltage +characteristic from that all that would + + align:start position:0% +characteristic from that all that would + + + align:start position:0% +characteristic from that all that would +have happened is instead of getting + + align:start position:0% +have happened is instead of getting + + + align:start position:0% +have happened is instead of getting +a + + align:start position:0% +a + + + align:start position:0% +a +slope or instead of getting a ripple + + align:start position:0% +slope or instead of getting a ripple + + + align:start position:0% +slope or instead of getting a ripple +wave form that looked like a perfect + + align:start position:0% +wave form that looked like a perfect + + + align:start position:0% +wave form that looked like a perfect +triangle wave like I drew here um all + + align:start position:0% +triangle wave like I drew here um all + + + align:start position:0% +triangle wave like I drew here um all +that would have happened is I would have + + align:start position:0% +that would have happened is I would have + + + align:start position:0% +that would have happened is I would have +gotten a different version with a + + align:start position:0% +gotten a different version with a + + + align:start position:0% +gotten a different version with a +slightly different curvature and the + + align:start position:0% +slightly different curvature and the + + + align:start position:0% +slightly different curvature and the +peak to Peak Ripple would have been + + align:start position:0% +peak to Peak Ripple would have been + + + align:start position:0% +peak to Peak Ripple would have been +exactly the same thing okay so I can + + align:start position:0% +exactly the same thing okay so I can + + + align:start position:0% +exactly the same thing okay so I can +make these approximations ignore the + + align:start position:0% +make these approximations ignore the + + + align:start position:0% +make these approximations ignore the +inductor current Ripple for calculating + + align:start position:0% +inductor current Ripple for calculating + + + align:start position:0% +inductor current Ripple for calculating +the capacitor bolt to Ripple and vice + + align:start position:0% +the capacitor bolt to Ripple and vice + + + align:start position:0% +the capacitor bolt to Ripple and vice +versa and I still get the right + + align:start position:0% +versa and I still get the right + + + align:start position:0% +versa and I still get the right +answer okay and what those have given me + + align:start position:0% +answer okay and what those have given me + + + align:start position:0% +answer okay and what those have given me +is a means to get to how big a capacitor + + align:start position:0% +is a means to get to how big a capacitor + + + align:start position:0% +is a means to get to how big a capacitor +do I need to get to a certain capacitor + + align:start position:0% +do I need to get to a certain capacitor + + + align:start position:0% +do I need to get to a certain capacitor +voltage Ripple and how big an inductor + + align:start position:0% +voltage Ripple and how big an inductor + + + align:start position:0% +voltage Ripple and how big an inductor +do I need to get to a certain inductor + + align:start position:0% +do I need to get to a certain inductor + + + align:start position:0% +do I need to get to a certain inductor +current + + align:start position:0% + + + + align:start position:0% + +Ripple + + align:start position:0% + + + + align:start position:0% + +questions so I would say that you know + + align:start position:0% +questions so I would say that you know + + + align:start position:0% +questions so I would say that you know +if I was going to sit down and design a + + align:start position:0% +if I was going to sit down and design a + + + align:start position:0% +if I was going to sit down and design a +converter I might start to think about + + align:start position:0% +converter I might start to think about + + + align:start position:0% +converter I might start to think about +hey um + + align:start position:0% +hey um + + + align:start position:0% +hey um +how much Ripple is tolerable right + + align:start position:0% +how much Ripple is tolerable right + + + align:start position:0% +how much Ripple is tolerable right +that's sort of an application thing + + align:start position:0% +that's sort of an application thing + + + align:start position:0% +that's sort of an application thing +right I'm building this boost converter + + align:start position:0% +right I'm building this boost converter + + + align:start position:0% +right I'm building this boost converter +to power some thing or other and perhaps + + align:start position:0% +to power some thing or other and perhaps + + + align:start position:0% +to power some thing or other and perhaps +my the specifications I'm giving you for + + align:start position:0% +my the specifications I'm giving you for + + + align:start position:0% +my the specifications I'm giving you for +the system is oh you're allowed you know + + align:start position:0% +the system is oh you're allowed you know + + + align:start position:0% +the system is oh you're allowed you know +100 Mill volts of Ripple on top of + + align:start position:0% +100 Mill volts of Ripple on top of + + + align:start position:0% +100 Mill volts of Ripple on top of +whatever your you know 50 volts of + + align:start position:0% +whatever your you know 50 volts of + + + align:start position:0% +whatever your you know 50 volts of +output is or something right somebody's + + align:start position:0% +output is or something right somebody's + + + align:start position:0% +output is or something right somebody's +going to tell you you're going to have + + align:start position:0% +going to tell you you're going to have + + + align:start position:0% +going to tell you you're going to have +this much voltage + + align:start position:0% +this much voltage + + + align:start position:0% +this much voltage +Ripple or this much current Ripple + + align:start position:0% +Ripple or this much current Ripple + + + align:start position:0% +Ripple or this much current Ripple +allowed into the input okay now one way + + align:start position:0% +allowed into the input okay now one way + + + align:start position:0% +allowed into the input okay now one way +to get those is just to make these + + align:start position:0% +to get those is just to make these + + + align:start position:0% +to get those is just to make these +components bigger we'll see other ways + + align:start position:0% +components bigger we'll see other ways + + + align:start position:0% +components bigger we'll see other ways +to reduce those by adding higher order + + align:start position:0% +to reduce those by adding higher order + + + align:start position:0% +to reduce those by adding higher order +filters and that kind of thing but this + + align:start position:0% +filters and that kind of thing but this + + + align:start position:0% +filters and that kind of thing but this +is a pretty good place to start to get L + + align:start position:0% +is a pretty good place to start to get L + + + align:start position:0% +is a pretty good place to start to get L +and C + + align:start position:0% +and C + + + align:start position:0% +and C +values okay and you notice in either + + align:start position:0% +values okay and you notice in either + + + align:start position:0% +values okay and you notice in either +case what I ended up with is triangular + + align:start position:0% +case what I ended up with is triangular + + + align:start position:0% +case what I ended up with is triangular +shaped + + align:start position:0% +shaped + + + align:start position:0% +shaped +ripples okay because essentially we're + + align:start position:0% +ripples okay because essentially we're + + + align:start position:0% +ripples okay because essentially we're +assuming that the currents just go the + + align:start position:0% +assuming that the currents just go the + + + align:start position:0% +assuming that the currents just go the +Ripple currents just going into the + + align:start position:0% +Ripple currents just going into the + + + align:start position:0% +Ripple currents just going into the +corresponding passive component a + + align:start position:0% +corresponding passive component a + + + align:start position:0% +corresponding passive component a +constant current is going to a passive + + align:start position:0% +constant current is going to a passive + + + align:start position:0% +constant current is going to a passive +component I get a triangular Ripple + + align:start position:0% +component I get a triangular Ripple + + + align:start position:0% +component I get a triangular Ripple +waveform okay well we can actually use + + align:start position:0% +waveform okay well we can actually use + + + align:start position:0% +waveform okay well we can actually use +that to our advantage we can kind of say + + align:start position:0% +that to our advantage we can kind of say + + + align:start position:0% +that to our advantage we can kind of say +okay any such + + align:start position:0% + + + + align:start position:0% + +component you know suppose I have some + + align:start position:0% +component you know suppose I have some + + + align:start position:0% +component you know suppose I have some +waveform I'm going to call X of + + align:start position:0% +waveform I'm going to call X of + + + align:start position:0% +waveform I'm going to call X of +T okay and maybe it has some DC value + + align:start position:0% +T okay and maybe it has some DC value + + + align:start position:0% +T okay and maybe it has some DC value +X that I'll call capital x this could be + + align:start position:0% +X that I'll call capital x this could be + + + align:start position:0% +X that I'll call capital x this could be +a Capac fter voltage or an inductor + + align:start position:0% +a Capac fter voltage or an inductor + + + align:start position:0% +a Capac fter voltage or an inductor +current and then maybe it has some + + align:start position:0% +current and then maybe it has some + + + align:start position:0% +current and then maybe it has some +triangular Ripple on it like + + align:start position:0% +triangular Ripple on it like + + + align:start position:0% +triangular Ripple on it like +this + + align:start position:0% + + + + align:start position:0% + +okay and so then I'll have + + align:start position:0% +okay and so then I'll have + + + align:start position:0% +okay and so then I'll have +some Peak + + align:start position:0% + + + + align:start position:0% + +value I'll call this x + + align:start position:0% +value I'll call this x + + + align:start position:0% +value I'll call this x +Peak and I'll call + + align:start position:0% +Peak and I'll call + + + align:start position:0% +Peak and I'll call +this x + + align:start position:0% +this x + + + align:start position:0% +this x +Min okay + + align:start position:0% +Min okay + + + align:start position:0% +Min okay +and if this + + align:start position:0% + + + + align:start position:0% + +is Delta X Peak to Peak okay it turns + + align:start position:0% +is Delta X Peak to Peak okay it turns + + + align:start position:0% +is Delta X Peak to Peak okay it turns +out that for triangular Ripple the any + + align:start position:0% +out that for triangular Ripple the any + + + align:start position:0% +out that for triangular Ripple the any +triangle wave like this the average is + + align:start position:0% +triangle wave like this the average is + + + align:start position:0% +triangle wave like this the average is +exactly halfway between the + + align:start position:0% +exactly halfway between the + + + align:start position:0% +exactly halfway between the +Peaks that means that this + + align:start position:0% +Peaks that means that this + + + align:start position:0% +Peaks that means that this +is Delta X Peak to Peak over two and + + align:start position:0% +is Delta X Peak to Peak over two and + + + align:start position:0% +is Delta X Peak to Peak over two and +this is Delta X Peak to Peak over 2 all + + align:start position:0% +this is Delta X Peak to Peak over 2 all + + + align:start position:0% +this is Delta X Peak to Peak over 2 all +right that's just a property of triangle + + align:start position:0% +right that's just a property of triangle + + + align:start position:0% +right that's just a property of triangle +waves + + align:start position:0% +waves + + + align:start position:0% +waves +okay why am I getting to that because we + + align:start position:0% +okay why am I getting to that because we + + + align:start position:0% +okay why am I getting to that because we +might Define the Ripple ratio + + align:start position:0% +might Define the Ripple ratio + + + align:start position:0% +might Define the Ripple ratio +okay + + align:start position:0% + + + + align:start position:0% + +um and I'm going to call this script R + + align:start position:0% +um and I'm going to call this script R + + + align:start position:0% +um and I'm going to call this script R +subx and I'm going to Define this to be + + align:start position:0% +subx and I'm going to Define this to be + + + align:start position:0% +subx and I'm going to Define this to be +equal to Delta X Peak to Peak / two + + align:start position:0% +equal to Delta X Peak to Peak / two + + + align:start position:0% +equal to Delta X Peak to Peak / two +that's the sort of the mean middle the + + align:start position:0% +that's the sort of the mean middle the + + + align:start position:0% +that's the sort of the mean middle the +average to the peak normalized to + + align:start position:0% +average to the peak normalized to + + + align:start position:0% +average to the peak normalized to +X + + align:start position:0% +X + + + align:start position:0% +X +right so this is sort of you might think + + align:start position:0% +right so this is sort of you might think + + + align:start position:0% +right so this is sort of you might think +of this as being like a percentage + + align:start position:0% +of this as being like a percentage + + + align:start position:0% +of this as being like a percentage +Ripple or a fraction Ripple okay why am + + align:start position:0% +Ripple or a fraction Ripple okay why am + + + align:start position:0% +Ripple or a fraction Ripple okay why am +I interested in that I'm interested in + + align:start position:0% +I interested in that I'm interested in + + + align:start position:0% +I interested in that I'm interested in +that because you know 100 molts a ripple + + align:start position:0% +that because you know 100 molts a ripple + + + align:start position:0% +that because you know 100 molts a ripple +on top of half a volt is a lot 100 Mill + + align:start position:0% +on top of half a volt is a lot 100 Mill + + + align:start position:0% +on top of half a volt is a lot 100 Mill +volts a ripple on top of 100 volts maybe + + align:start position:0% +volts a ripple on top of 100 volts maybe + + + align:start position:0% +volts a ripple on top of 100 volts maybe +it's not so big right so we might want + + align:start position:0% +it's not so big right so we might want + + + align:start position:0% +it's not so big right so we might want +to normally ize the Ripple we consider + + align:start position:0% +to normally ize the Ripple we consider + + + align:start position:0% +to normally ize the Ripple we consider +to the average value of any waveform + + align:start position:0% +to the average value of any waveform + + + align:start position:0% +to the average value of any waveform +inductor current or capacitor voltage + + align:start position:0% +inductor current or capacitor voltage + + + align:start position:0% +inductor current or capacitor voltage +okay so people often talk about the + + align:start position:0% +okay so people often talk about the + + + align:start position:0% +okay so people often talk about the +Ripple ratio of the waveforms or it's + + align:start position:0% +Ripple ratio of the waveforms or it's + + + align:start position:0% +Ripple ratio of the waveforms or it's +sort of a version of the percentage + + align:start position:0% +sort of a version of the percentage + + + align:start position:0% +sort of a version of the percentage +Ripple if you multiply by 100 okay um I + + align:start position:0% +Ripple if you multiply by 100 okay um I + + + align:start position:0% +Ripple if you multiply by 100 okay um I +will say that if you look in the + + align:start position:0% +will say that if you look in the + + + align:start position:0% +will say that if you look in the +literature there there's a skew in how + + align:start position:0% +literature there there's a skew in how + + + align:start position:0% +literature there there's a skew in how +people Define things some people Define + + align:start position:0% +people Define things some people Define + + + align:start position:0% +people Define things some people Define +the Ripple ratio as being Delta X Peak + + align:start position:0% +the Ripple ratio as being Delta X Peak + + + align:start position:0% +the Ripple ratio as being Delta X Peak +to Peak over X and some people Define it + + align:start position:0% +to Peak over X and some people Define it + + + align:start position:0% +to Peak over X and some people Define it +as Delta X Peak Peak over two overx you + + align:start position:0% +as Delta X Peak Peak over two overx you + + + align:start position:0% +as Delta X Peak Peak over two overx you +just got to be careful of what's being + + align:start position:0% +just got to be careful of what's being + + + align:start position:0% +just got to be careful of what's being +referred to when you read the literature + + align:start position:0% +referred to when you read the literature + + + align:start position:0% +referred to when you read the literature +um I kind of like this definition a + + align:start position:0% +um I kind of like this definition a + + + align:start position:0% +um I kind of like this definition a +because what it it's what is used in the + + align:start position:0% +because what it it's what is used in the + + + align:start position:0% +because what it it's what is used in the +text but the one of the nice things + + align:start position:0% +text but the one of the nice things + + + align:start position:0% +text but the one of the nice things +about it is you can then say x a + + align:start position:0% +about it is you can then say x a + + + align:start position:0% +about it is you can then say x a +peak is just simply equal to the DC + + align:start position:0% +peak is just simply equal to the DC + + + align:start position:0% +peak is just simply equal to the DC +value times 1 plus the Ripple ratio of + + align:start position:0% +value times 1 plus the Ripple ratio of + + + align:start position:0% +value times 1 plus the Ripple ratio of +X all + + align:start position:0% +X all + + + align:start position:0% +X all +right and so it's convenient to use this + + align:start position:0% +right and so it's convenient to use this + + + align:start position:0% +right and so it's convenient to use this +form of the definition of Ripple + + align:start position:0% +form of the definition of Ripple + + + align:start position:0% +form of the definition of Ripple +ratio any questions about + + align:start position:0% + + + + align:start position:0% + +that okay so + + align:start position:0% +that okay so + + + align:start position:0% +that okay so +um how might I think about using this + + align:start position:0% +um how might I think about using this + + + align:start position:0% +um how might I think about using this +kind of definition well I might talk + + align:start position:0% +kind of definition well I might talk + + + align:start position:0% +kind of definition well I might talk +about um sort of V I might talk about + + align:start position:0% +about um sort of V I might talk about + + + align:start position:0% +about um sort of V I might talk about +the Ripple ratio in the capacitor + + align:start position:0% +the Ripple ratio in the capacitor + + + align:start position:0% +the Ripple ratio in the capacitor +voltage as being uh you know Delta VC + + align:start position:0% +voltage as being uh you know Delta VC + + + align:start position:0% +voltage as being uh you know Delta VC +Peak to Peak over two / VC and the + + align:start position:0% +Peak to Peak over two / VC and the + + + align:start position:0% +Peak to Peak over two / VC and the +Ripple ratio and the inductor current is + + align:start position:0% +Ripple ratio and the inductor current is + + + align:start position:0% +Ripple ratio and the inductor current is +being Delta I Peak to Peak over 2 / the + + align:start position:0% +being Delta I Peak to Peak over 2 / the + + + align:start position:0% +being Delta I Peak to Peak over 2 / the +DC inductor current + + align:start position:0% +DC inductor current + + + align:start position:0% +DC inductor current +okay and we can then use the Ripple + + align:start position:0% +okay and we can then use the Ripple + + + align:start position:0% +okay and we can then use the Ripple +ratio that I'm talking about to + + align:start position:0% +ratio that I'm talking about to + + + align:start position:0% +ratio that I'm talking about to +relate um sort of average values to + + align:start position:0% +relate um sort of average values to + + + align:start position:0% +relate um sort of average values to +actual Peak values because we know the + + align:start position:0% +actual Peak values because we know the + + + align:start position:0% +actual Peak values because we know the +Ripple's triangular okay there's another + + align:start position:0% +Ripple's triangular okay there's another + + + align:start position:0% +Ripple's triangular okay there's another +way we can use this too is a way to + + align:start position:0% +way we can use this too is a way to + + + align:start position:0% +way we can use this too is a way to +start thinking about as I ch change the + + align:start position:0% +start thinking about as I ch change the + + + align:start position:0% +start thinking about as I ch change the +Ripple ratio of my converter how much + + align:start position:0% +Ripple ratio of my converter how much + + + align:start position:0% +Ripple ratio of my converter how much +Ripple is allowed in my converter how + + align:start position:0% +Ripple is allowed in my converter how + + + align:start position:0% +Ripple is allowed in my converter how +big does the converter get okay I've + + align:start position:0% +big does the converter get okay I've + + + align:start position:0% +big does the converter get okay I've +come up with Expressions I need this big + + align:start position:0% +come up with Expressions I need this big + + + align:start position:0% +come up with Expressions I need this big +an inductor or this big a capacitor if I + + align:start position:0% +an inductor or this big a capacitor if I + + + align:start position:0% +an inductor or this big a capacitor if I +knew those factors but it might be nice + + align:start position:0% +knew those factors but it might be nice + + + align:start position:0% +knew those factors but it might be nice +to be able to express that a little bit + + align:start position:0% +to be able to express that a little bit + + + align:start position:0% +to be able to express that a little bit +better H how does that relate to the + + align:start position:0% +better H how does that relate to the + + + align:start position:0% +better H how does that relate to the +size of the + + align:start position:0% + + + + align:start position:0% + +component that's a very complicated + + align:start position:0% +component that's a very complicated + + + align:start position:0% +component that's a very complicated +question in general right saying you + + align:start position:0% +question in general right saying you + + + align:start position:0% +question in general right saying you +know + + align:start position:0% +know + + + align:start position:0% +know +how physically big is my inductor or + + align:start position:0% +how physically big is my inductor or + + + align:start position:0% +how physically big is my inductor or +capacitor going to be that that's a hard + + align:start position:0% +capacitor going to be that that's a hard + + + align:start position:0% +capacitor going to be that that's a hard +question to answer because and we're + + align:start position:0% +question to answer because and we're + + + align:start position:0% +question to answer because and we're +going to see that when we design we + + align:start position:0% +going to see that when we design we + + + align:start position:0% +going to see that when we design we +start to design the components + + align:start position:0% +start to design the components + + + align:start position:0% +start to design the components +themselves but it's reasonable to expect + + align:start position:0% +themselves but it's reasonable to expect + + + align:start position:0% +themselves but it's reasonable to expect +that to first + + align:start position:0% +that to first + + + align:start position:0% +that to first +order the size of your component the + + align:start position:0% +order the size of your component the + + + align:start position:0% +order the size of your component the +physical size of your component ought to + + align:start position:0% +physical size of your component ought to + + + align:start position:0% +physical size of your component ought to +be related to the amount of energy it + + align:start position:0% +be related to the amount of energy it + + + align:start position:0% +be related to the amount of energy it +stores right if I if I have to store + + align:start position:0% +stores right if I if I have to store + + + align:start position:0% +stores right if I if I have to store +twice as much energy and I get a certain + + align:start position:0% +twice as much energy and I get a certain + + + align:start position:0% +twice as much energy and I get a certain +energy density if you imagine + + align:start position:0% +energy density if you imagine + + + align:start position:0% +energy density if you imagine +of storage then twice as much energy + + align:start position:0% +of storage then twice as much energy + + + align:start position:0% +of storage then twice as much energy +storage ought to be twice as much size + + align:start position:0% +storage ought to be twice as much size + + + align:start position:0% +storage ought to be twice as much size +to first order right + + align:start position:0% +to first order right + + + align:start position:0% +to first order right +so Engineers often + + align:start position:0% +so Engineers often + + + align:start position:0% +so Engineers often +use energy storage of the components as + + align:start position:0% +use energy storage of the components as + + + align:start position:0% +use energy storage of the components as +a very crude standing for how physically + + align:start position:0% +a very crude standing for how physically + + + align:start position:0% +a very crude standing for how physically +big the components are going to be and I + + align:start position:0% +big the components are going to be and I + + + align:start position:0% +big the components are going to be and I +want to emphasize it's a very crude + + align:start position:0% +want to emphasize it's a very crude + + + align:start position:0% +want to emphasize it's a very crude +standing it's not true necessarily that + + align:start position:0% +standing it's not true necessarily that + + + align:start position:0% +standing it's not true necessarily that +it's a you know it's exactly + + align:start position:0% +it's a you know it's exactly + + + align:start position:0% +it's a you know it's exactly +proportional relationship or something + + align:start position:0% +proportional relationship or something + + + align:start position:0% +proportional relationship or something +like that it's not but it's at least a + + align:start position:0% +like that it's not but it's at least a + + + align:start position:0% +like that it's not but it's at least a +rough measure that you can get your + + align:start position:0% +rough measure that you can get your + + + align:start position:0% +rough measure that you can get your +hands + + align:start position:0% +hands + + + align:start position:0% +hands +around okay so let's think about what + + align:start position:0% +around okay so let's think about what + + + align:start position:0% +around okay so let's think about what +that might mean + + align:start position:0% +that might mean + + + align:start position:0% +that might mean +okay well um let's think about um the + + align:start position:0% +okay well um let's think about um the + + + align:start position:0% +okay well um let's think about um the +energy storage of the capacitor right + + align:start position:0% +energy storage of the capacitor right + + + align:start position:0% +energy storage of the capacitor right +I've got an expression here for the + + align:start position:0% +I've got an expression here for the + + + align:start position:0% +I've got an expression here for the +energy storage of the + + align:start position:0% +energy storage of the + + + align:start position:0% +energy storage of the +capacitor okay um so we said that + + align:start position:0% +capacitor okay um so we said that + + + align:start position:0% +capacitor okay um so we said that +c has to be of this size + + align:start position:0% +c has to be of this size + + + align:start position:0% +c has to be of this size +okay and in my Boost converter iil is + + align:start position:0% +okay and in my Boost converter iil is + + + align:start position:0% +okay and in my Boost converter iil is +the same thing as + + align:start position:0% +the same thing as + + + align:start position:0% +the same thing as +i1 + + align:start position:0% +i1 + + + align:start position:0% +i1 +right so um what I get is for a boost + + align:start position:0% +right so um what I get is for a boost + + + align:start position:0% +right so um what I get is for a boost +converter then I get C is greater than + + align:start position:0% +converter then I get C is greater than + + + align:start position:0% +converter then I get C is greater than +or equal to + + align:start position:0% +or equal to + + + align:start position:0% +or equal to +D * 1us d i is the same thing as I + + align:start position:0% +D * 1us d i is the same thing as I + + + align:start position:0% +D * 1us d i is the same thing as I +Capital + + align:start position:0% +Capital + + + align:start position:0% +Capital +i1 uh this is the switching period + + align:start position:0% +i1 uh this is the switching period + + + align:start position:0% +i1 uh this is the switching period +divided by Delta VC Peak to Peak over + + align:start position:0% +divided by Delta VC Peak to Peak over + + + align:start position:0% +divided by Delta VC Peak to Peak over +two I'm sorry Delta VC Peak to Peak okay + + align:start position:0% +two I'm sorry Delta VC Peak to Peak okay + + + align:start position:0% +two I'm sorry Delta VC Peak to Peak okay +let me substitute this + + align:start position:0% +let me substitute this + + + align:start position:0% +let me substitute this +in so that means C is got to be greater + + align:start position:0% +in so that means C is got to be greater + + + align:start position:0% +in so that means C is got to be greater +than or equal to D * 1us d i1 + + align:start position:0% +than or equal to D * 1us d i1 + + + align:start position:0% +than or equal to D * 1us d i1 +t + + align:start position:0% +t + + + align:start position:0% +t +uh divided by + + align:start position:0% + + + + align:start position:0% + +2 DC which is also equal to + + align:start position:0% +2 DC which is also equal to + + + align:start position:0% +2 DC which is also equal to +V2 uh + + align:start position:0% + + + + align:start position:0% + +RC Ripple ratio of the capacitor okay so + + align:start position:0% +RC Ripple ratio of the capacitor okay so + + + align:start position:0% +RC Ripple ratio of the capacitor okay so +this is the same thing just expressed in + + align:start position:0% +this is the same thing just expressed in + + + align:start position:0% +this is the same thing just expressed in +terms of input and output + + align:start position:0% +terms of input and output + + + align:start position:0% +terms of input and output +quantities and uh the Ripple ratio on + + align:start position:0% +quantities and uh the Ripple ratio on + + + align:start position:0% +quantities and uh the Ripple ratio on +the capacitor how much percentage Ripple + + align:start position:0% +the capacitor how much percentage Ripple + + + align:start position:0% +the capacitor how much percentage Ripple +am I going to allow in the capacitor + + align:start position:0% +am I going to allow in the capacitor + + + align:start position:0% +am I going to allow in the capacitor +everybody buy + + align:start position:0% + + + + align:start position:0% + +that if I then came back and said okay + + align:start position:0% +that if I then came back and said okay + + + align:start position:0% +that if I then came back and said okay +how much energy is stored in the + + align:start position:0% +how much energy is stored in the + + + align:start position:0% +how much energy is stored in the +capacitor energy in the capacitor is + + align:start position:0% +capacitor energy in the capacitor is + + + align:start position:0% +capacitor energy in the capacitor is +simply equal to 12 C VC Peak squared + + align:start position:0% +simply equal to 12 C VC Peak squared + + + align:start position:0% +simply equal to 12 C VC Peak squared +right if I got to go buy a capacitor and + + align:start position:0% +right if I got to go buy a capacitor and + + + align:start position:0% +right if I got to go buy a capacitor and +I want to know how much energy it stores + + align:start position:0% +I want to know how much energy it stores + + + align:start position:0% +I want to know how much energy it stores +I care about the peak voltage I'm going + + align:start position:0% +I care about the peak voltage I'm going + + + align:start position:0% +I care about the peak voltage I'm going +to put on the capacitor because that's + + align:start position:0% +to put on the capacitor because that's + + + align:start position:0% +to put on the capacitor because that's +what the capacitor is rated for and I + + align:start position:0% +what the capacitor is rated for and I + + + align:start position:0% +what the capacitor is rated for and I +care about the capacitance value I'm + + align:start position:0% +care about the capacitance value I'm + + + align:start position:0% +care about the capacitance value I'm +using and that's energy is2 cv^ s + + align:start position:0% +using and that's energy is2 cv^ s + + + align:start position:0% +using and that's energy is2 cv^ s +everybody buy + + align:start position:0% +everybody buy + + + align:start position:0% +everybody buy +that so what is that going to + + align:start position:0% + + + + align:start position:0% + +be all that's going to be is + + align:start position:0% +be all that's going to be is + + + align:start position:0% +be all that's going to be is +EC is equal to 12 I'm just going to + + align:start position:0% +EC is equal to 12 I'm just going to + + + align:start position:0% +EC is equal to 12 I'm just going to +substitute in this here so it's going to + + align:start position:0% +substitute in this here so it's going to + + + align:start position:0% +substitute in this here so it's going to +be D * 1 - d i1 t over + + align:start position:0% +be D * 1 - d i1 t over + + + align:start position:0% +be D * 1 - d i1 t over +2 V2 + + align:start position:0% +2 V2 + + + align:start position:0% +2 V2 +RC and v v Peak squar on the capacitor + + align:start position:0% +RC and v v Peak squar on the capacitor + + + align:start position:0% +RC and v v Peak squar on the capacitor +is simply equal to V2 + + align:start position:0% +is simply equal to V2 + + + align:start position:0% +is simply equal to V2 +Time 1 plus the Ripple ratio on the + + align:start position:0% +Time 1 plus the Ripple ratio on the + + + align:start position:0% +Time 1 plus the Ripple ratio on the +capacitor quantity + + align:start position:0% +capacitor quantity + + + align:start position:0% +capacitor quantity +squared right this is V Peak it's V2 * 1 + + align:start position:0% +squared right this is V Peak it's V2 * 1 + + + align:start position:0% +squared right this is V Peak it's V2 * 1 +ratio okay if I were then to rewrite + + align:start position:0% +ratio okay if I were then to rewrite + + + align:start position:0% +ratio okay if I were then to rewrite +this what I would get is + + align:start position:0% +this what I would get is + + + align:start position:0% +this what I would get is +D time if I look at this by the + + align:start position:0% +D time if I look at this by the + + + align:start position:0% +D time if I look at this by the +way uh d d * 1 uh 1us di + + align:start position:0% +way uh d d * 1 uh 1us di + + + align:start position:0% +way uh d d * 1 uh 1us di +i1 is + + align:start position:0% +i1 is + + + align:start position:0% +i1 is +I2 right this is the same thing as + + align:start position:0% +I2 right this is the same thing as + + + align:start position:0% +I2 right this is the same thing as +I2 + + align:start position:0% +I2 + + + align:start position:0% +I2 +T over + + align:start position:0% +T over + + + align:start position:0% +T over +two I'm sorry over four 2 * 2 is over 4 + + align:start position:0% +two I'm sorry over four 2 * 2 is over 4 + + + align:start position:0% +two I'm sorry over four 2 * 2 is over 4 +then this is going to be v2^ 2 / V2 is + + align:start position:0% +then this is going to be v2^ 2 / V2 is + + + align:start position:0% +then this is going to be v2^ 2 / V2 is +just + + align:start position:0% +just + + + align:start position:0% +just +V2 and then times 1 plus the Ripple + + align:start position:0% +V2 and then times 1 plus the Ripple + + + align:start position:0% +V2 and then times 1 plus the Ripple +ratio squar over the Ripple + + align:start position:0% +ratio squar over the Ripple + + + align:start position:0% +ratio squar over the Ripple +ratio okay and I'll rewrite one more + + align:start position:0% +ratio okay and I'll rewrite one more + + + align:start position:0% +ratio okay and I'll rewrite one more +thing V2 * I2 is just the output power + + align:start position:0% +thing V2 * I2 is just the output power + + + align:start position:0% +thing V2 * I2 is just the output power +right so this is going to be D * P + + align:start position:0% +right so this is going to be D * P + + + align:start position:0% +right so this is going to be D * P +out time T / 4 + + align:start position:0% +out time T / 4 + + + align:start position:0% +out time T / 4 +Time 1 plus the Ripple ratio s over the + + align:start position:0% +Time 1 plus the Ripple ratio s over the + + + align:start position:0% +Time 1 plus the Ripple ratio s over the +Ripple ratio all right I apologize for + + align:start position:0% +Ripple ratio all right I apologize for + + + align:start position:0% +Ripple ratio all right I apologize for +all the math um this is the energy + + align:start position:0% +all the math um this is the energy + + + align:start position:0% +all the math um this is the energy +stored in the + + align:start position:0% +stored in the + + + align:start position:0% +stored in the +capacitor okay so why am I telling you + + align:start position:0% +capacitor okay so why am I telling you + + + align:start position:0% +capacitor okay so why am I telling you +this this tells + + align:start position:0% +this this tells + + + align:start position:0% +this this tells +me as a very broad function of Ripple + + align:start position:0% +me as a very broad function of Ripple + + + align:start position:0% +me as a very broad function of Ripple +and operating power and everything how + + align:start position:0% +and operating power and everything how + + + align:start position:0% +and operating power and everything how +much energy do I have to go put in that + + align:start position:0% +much energy do I have to go put in that + + + align:start position:0% +much energy do I have to go put in that +capacitor which I can use as a crude + + align:start position:0% +capacitor which I can use as a crude + + + align:start position:0% +capacitor which I can use as a crude +measure of how big and expensive that + + align:start position:0% +measure of how big and expensive that + + + align:start position:0% +measure of how big and expensive that +capacitor is going to be okay so what + + align:start position:0% +capacitor is going to be okay so what + + + align:start position:0% +capacitor is going to be okay so what +makes my capacitor requirement + + align:start position:0% +makes my capacitor requirement + + + align:start position:0% +makes my capacitor requirement +bigger it's proportion the energy + + align:start position:0% +bigger it's proportion the energy + + + align:start position:0% +bigger it's proportion the energy +storage which I'm claiming ought to be + + align:start position:0% +storage which I'm claiming ought to be + + + align:start position:0% +storage which I'm claiming ought to be +proportional to the size is proportional + + align:start position:0% +proportional to the size is proportional + + + align:start position:0% +proportional to the size is proportional +to the output power that's sort of + + align:start position:0% +to the output power that's sort of + + + align:start position:0% +to the output power that's sort of +physically reasonable right if I double + + align:start position:0% +physically reasonable right if I double + + + align:start position:0% +physically reasonable right if I double +the power maybe I need twice as much + + align:start position:0% +the power maybe I need twice as much + + + align:start position:0% +the power maybe I need twice as much +energy storage to do the same conversion + + align:start position:0% +energy storage to do the same conversion + + + align:start position:0% +energy storage to do the same conversion +function okay it's proportional to D + + align:start position:0% +function okay it's proportional to D + + + align:start position:0% +function okay it's proportional to D +well keep in mind the bigger D is the + + align:start position:0% +well keep in mind the bigger D is the + + + align:start position:0% +well keep in mind the bigger D is the +bigger the voltage conversion ratio is + + align:start position:0% +bigger the voltage conversion ratio is + + + align:start position:0% +bigger the voltage conversion ratio is +right because V2 is V1 over 1 minus D so + + align:start position:0% +right because V2 is V1 over 1 minus D so + + + align:start position:0% +right because V2 is V1 over 1 minus D so +the more I'm stepping up voltage the + + align:start position:0% +the more I'm stepping up voltage the + + + align:start position:0% +the more I'm stepping up voltage the +bigger D I need so if I want to do a + + align:start position:0% +bigger D I need so if I want to do a + + + align:start position:0% +bigger D I need so if I want to do a +bigger Step Up conversion that means I + + align:start position:0% +bigger Step Up conversion that means I + + + align:start position:0% +bigger Step Up conversion that means I +need more energy storage in my + + align:start position:0% +need more energy storage in my + + + align:start position:0% +need more energy storage in my +capacitor + + align:start position:0% +capacitor + + + align:start position:0% +capacitor +okay also notice that this function over + + align:start position:0% +okay also notice that this function over + + + align:start position:0% +okay also notice that this function over +here is some function of the Ripple + + align:start position:0% +here is some function of the Ripple + + + align:start position:0% +here is some function of the Ripple +ratio it turns out for most ranges of + + align:start position:0% +ratio it turns out for most ranges of + + + align:start position:0% +ratio it turns out for most ranges of +Ripple ratio which I care about which + + align:start position:0% +Ripple ratio which I care about which + + + align:start position:0% +Ripple ratio which I care about which +are much less than one making Ripple + + align:start position:0% +are much less than one making Ripple + + + align:start position:0% +are much less than one making Ripple +ratio smaller Mak this fraction + + align:start position:0% +ratio smaller Mak this fraction + + + align:start position:0% +ratio smaller Mak this fraction +bigger okay so if I tell you I need less + + align:start position:0% +bigger okay so if I tell you I need less + + + align:start position:0% +bigger okay so if I tell you I need less +Ripple smaller Ripple ratio suddenly my + + align:start position:0% +Ripple smaller Ripple ratio suddenly my + + + align:start position:0% +Ripple smaller Ripple ratio suddenly my +energy storage got bigger all right so + + align:start position:0% +energy storage got bigger all right so + + + align:start position:0% +energy storage got bigger all right so +that says if I want really nice input + + align:start position:0% +that says if I want really nice input + + + align:start position:0% +that says if I want really nice input +and output waveforms I'm going to need + + align:start position:0% +and output waveforms I'm going to need + + + align:start position:0% +and output waveforms I'm going to need +more energy storage okay lastly notice + + align:start position:0% +more energy storage okay lastly notice + + + align:start position:0% +more energy storage okay lastly notice +that this is the switching period here + + align:start position:0% +that this is the switching period here + + + align:start position:0% +that this is the switching period here +or one over the switching frequency the + + align:start position:0% +or one over the switching frequency the + + + align:start position:0% +or one over the switching frequency the +energy storage I need is proportional to + + align:start position:0% +energy storage I need is proportional to + + + align:start position:0% +energy storage I need is proportional to +the switching period or one over the + + align:start position:0% +the switching period or one over the + + + align:start position:0% +the switching period or one over the +switching frequency that means if I + + align:start position:0% +switching frequency that means if I + + + align:start position:0% +switching frequency that means if I +switch slowly + + align:start position:0% +switch slowly + + + align:start position:0% +switch slowly +I need very big capacitors and I showed + + align:start position:0% +I need very big capacitors and I showed + + + align:start position:0% +I need very big capacitors and I showed +you this for the capacitor in the + + align:start position:0% +you this for the capacitor in the + + + align:start position:0% +you this for the capacitor in the +lecture notes I put the equivalent + + align:start position:0% +lecture notes I put the equivalent + + + align:start position:0% +lecture notes I put the equivalent +expression for the inductor basically if + + align:start position:0% +expression for the inductor basically if + + + align:start position:0% +expression for the inductor basically if +you just substitute Ripple ratio of the + + align:start position:0% +you just substitute Ripple ratio of the + + + align:start position:0% +you just substitute Ripple ratio of the +inductor for capacitor you get the same + + align:start position:0% +inductor for capacitor you get the same + + + align:start position:0% +inductor for capacitor you get the same +result okay so what that says is either + + align:start position:0% +result okay so what that says is either + + + align:start position:0% +result okay so what that says is either +the inductor or capacitor going to get + + align:start position:0% +the inductor or capacitor going to get + + + align:start position:0% +the inductor or capacitor going to get +bigger and bigger and bigger if I either + + align:start position:0% +bigger and bigger and bigger if I either + + + align:start position:0% +bigger and bigger and bigger if I either +um reduce my switching frequency or + + align:start position:0% +um reduce my switching frequency or + + + align:start position:0% +um reduce my switching frequency or +reduce the amount of + + align:start position:0% +reduce the amount of + + + align:start position:0% +reduce the amount of +Ripple okay and that's what gives me a + + align:start position:0% +Ripple okay and that's what gives me a + + + align:start position:0% +Ripple okay and that's what gives me a +means to start saying gez I better limit + + align:start position:0% +means to start saying gez I better limit + + + align:start position:0% +means to start saying gez I better limit +if I want to limit the physical size or + + align:start position:0% +if I want to limit the physical size or + + + align:start position:0% +if I want to limit the physical size or +the cost of this thing I'm going to have + + align:start position:0% +the cost of this thing I'm going to have + + + align:start position:0% +the cost of this thing I'm going to have +to start making some decisions about how + + align:start position:0% +to start making some decisions about how + + + align:start position:0% +to start making some decisions about how +I pick my + + align:start position:0% +I pick my + + + align:start position:0% +I pick my +components + + align:start position:0% +components + + + align:start position:0% +components +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and that just gives you a A first order + + align:start position:0% +and that just gives you a A first order + + + align:start position:0% +and that just gives you a A first order +place to be in terms of picking + + align:start position:0% +place to be in terms of picking + + + align:start position:0% +place to be in terms of picking +component values okay and this is only + + align:start position:0% +component values okay and this is only + + + align:start position:0% +component values okay and this is only +one thing this is based on Ripple we're + + align:start position:0% +one thing this is based on Ripple we're + + + align:start position:0% +one thing this is based on Ripple we're +also going to talk about based on things + + align:start position:0% +also going to talk about based on things + + + align:start position:0% +also going to talk about based on things +like transient performance and that kind + + align:start position:0% +like transient performance and that kind + + + align:start position:0% +like transient performance and that kind +of thing but this gives you at least a + + align:start position:0% +of thing but this gives you at least a + + + align:start position:0% +of thing but this gives you at least a +place to start for picking component + + align:start position:0% +place to start for picking component + + + align:start position:0% +place to start for picking component +values to get down to certain allowed + + align:start position:0% +values to get down to certain allowed + + + align:start position:0% +values to get down to certain allowed +levels of + + align:start position:0% +levels of + + + align:start position:0% +levels of +Ripple any questions about + + align:start position:0% + + + + align:start position:0% + +that these results are all for the Boost + + align:start position:0% +that these results are all for the Boost + + + align:start position:0% +that these results are all for the Boost +converter these results for the Boost + + align:start position:0% +converter these results for the Boost + + + align:start position:0% +converter these results for the Boost +converter um you can derive exactly + + align:start position:0% +converter um you can derive exactly + + + align:start position:0% +converter um you can derive exactly +equivalent results for the buck + + align:start position:0% +equivalent results for the buck + + + align:start position:0% +equivalent results for the buck +converter or any other converter you + + align:start position:0% +converter or any other converter you + + + align:start position:0% +converter or any other converter you +want and people often do um I will say + + align:start position:0% +want and people often do um I will say + + + align:start position:0% +want and people often do um I will say +that if I said how much EC or eel is + + align:start position:0% +that if I said how much EC or eel is + + + align:start position:0% +that if I said how much EC or eel is +required for a boost converter at a + + align:start position:0% +required for a boost converter at a + + + align:start position:0% +required for a boost converter at a +certain conversion ratio and I went back + + align:start position:0% +certain conversion ratio and I went back + + + align:start position:0% +certain conversion ratio and I went back +and did it for the buck boost converter + + align:start position:0% +and did it for the buck boost converter + + + align:start position:0% +and did it for the buck boost converter +that we started with it' be + + align:start position:0% +that we started with it' be + + + align:start position:0% +that we started with it' be +significantly + + align:start position:0% +significantly + + + align:start position:0% +significantly +worse much more energy storage and what + + align:start position:0% +worse much more energy storage and what + + + align:start position:0% +worse much more energy storage and what +that would mean is I'm going to end up + + align:start position:0% +that would mean is I'm going to end up + + + align:start position:0% +that would mean is I'm going to end up +with a bigger more expensive converter + + align:start position:0% +with a bigger more expensive converter + + + align:start position:0% +with a bigger more expensive converter +and what what this comes down to is you + + align:start position:0% +and what what this comes down to is you + + + align:start position:0% +and what what this comes down to is you +know you're competing right like the + + align:start position:0% +know you're competing right like the + + + align:start position:0% +know you're competing right like the +other guy's designing something you're + + align:start position:0% +other guy's designing something you're + + + align:start position:0% +other guy's designing something you're +designing something and yours is smaller + + align:start position:0% +designing something and yours is smaller + + + align:start position:0% +designing something and yours is smaller +and more efficient because you've used + + align:start position:0% +and more efficient because you've used + + + align:start position:0% +and more efficient because you've used +less energy storage to do the same + + align:start position:0% +less energy storage to do the same + + + align:start position:0% +less energy storage to do the same +conversion function you know + + align:start position:0% +conversion function you know + + + align:start position:0% +conversion function you know +you can win or lose based on those + + align:start position:0% +you can win or lose based on those + + + align:start position:0% +you can win or lose based on those +decisions but yes you can derive similar + + align:start position:0% +decisions but yes you can derive similar + + + align:start position:0% +decisions but yes you can derive similar +results and the typical thing is true + + align:start position:0% +results and the typical thing is true + + + align:start position:0% +results and the typical thing is true +the more conversion transformation + + align:start position:0% +the more conversion transformation + + + align:start position:0% +the more conversion transformation +you're doing you tend to require more + + align:start position:0% +you're doing you tend to require more + + + align:start position:0% +you're doing you tend to require more +energy storage the lower the Ripple you + + align:start position:0% +energy storage the lower the Ripple you + + + align:start position:0% +energy storage the lower the Ripple you +need you require more energy storage the + + align:start position:0% +need you require more energy storage the + + + align:start position:0% +need you require more energy storage the +slower you switch or the higher the + + align:start position:0% +slower you switch or the higher the + + + align:start position:0% +slower you switch or the higher the +power you require more energy + + align:start position:0% +power you require more energy + + + align:start position:0% +power you require more energy +storage any other + + align:start position:0% + + + + align:start position:0% + +questions okay next time we'll start + + align:start position:0% +questions okay next time we'll start + + + align:start position:0% +questions okay next time we'll start +thinking a little bit more about + + align:start position:0% +thinking a little bit more about + + + align:start position:0% +thinking a little bit more about +conversion Ripple and what can happen in + + align:start position:0% +conversion Ripple and what can happen in + + + align:start position:0% +conversion Ripple and what can happen in +extreme cases have a great day \ No newline at end of file diff --git a/Q8SoG1OIveU.txt b/Q8SoG1OIveU.txt new file mode 100644 index 0000000000000000000000000000000000000000..6038d3efa565d97367db88b426552bfdad66b34a --- /dev/null +++ b/Q8SoG1OIveU.txt @@ -0,0 +1,2725 @@ +OPERATOR: The following content +is provided under a + +Creative Commons license. + +Your support will help MIT +OpenCourseWare continue to + +offer high quality educational +resources for free. + +To make a donation or view +additional materials from + +hundreds of MIT courses, visit +MIT OpenCourseWare at + +ocw.mit.edu. + +PROFESSOR: Last lecture we were +talking about classes, + +and object-oriented programming, +and we're going + +to come back to it today. + +I'm going to remind you, we were +talking about it because + +we suggested it is a really +powerful way of structuring + +systems, and that's really why +we want to use it, It's a very + +common way of structuring +systems. So today I'm going to + +pick up on a bunch of more +nuanced, or more complex if + +you like, ways of leveraging +the power of classes. + +But we're going to see a bunch +of examples that are going to + +give us a sense. + +I'm going to talk about +inheritance, we're going to + +talk about shadowing, we're +going to talk about iterators. + +But before get to it, I want to +start by just highlighting, + +sort of, what was the +point of classes? + +So I'll remind you. + +A class, I said, was basically +a template for an + +abstract data type. + +And this was really to drive +home this idea of modularity. + +I want the ability to say, I've +got a set of things that + +naturally belong together, +I'm going to cluster them + +together, I want to treat it +like it's a primitive, I want + +to treat it like it's a float +or an int or a string. + +Is this going to be a point +or a segment or something + +different like that. + +So it's really a way, as I +said, of just trying to + +cluster data together. + +And this is a notion of +modularity slash abstraction + +where I'm treating them +as primitives. + +But the second thing we talked +about is that we also have a + +set of methods, using the +special name method because + +we're talking classes. + +But basically functions that are +designed to deal with this + +data structure. + +We're trying to group those +together as well. + +So we cluster data +and methods. + +Second key thing we said was, +in the ideal case, which + +unfortunately Python isn't, but +we'll come back to that, + +in the ideal case, we would have +data hiding, and by data + +hiding, which is sort of a +version of encapsulation, what + +we meant was that you could +only get to the internal + +pieces of that data structure +through a proscribed method. + +Proscribed meaning it's +something I set up. + +So data hiding saying, you would +only access the parts + +through a method. + +And as we said, unfortunately +Python does not enforce this. + +Meaning that I could create one +of these data structures, + +ideally I'd have a method, that +I'm going to see some + +examples of that I used to get +the parts out, unfortunately + +in Python you could take the +name the instance dot some + +internal variable you'll +get it back. + +It is exposed. + +And this is actually just +not a good idea. + +So I suggested in my very bad +humor, that you practice + +computational hygiene and you +only use appropriate methods + +to get the parts out. + +OK didn't laugh the joke last +time, you're not going to + +laugh at it this time, +I don't blame you. + +All right, and then the last +piece of this is that we said + +the class is a template. + +When we call that class, +it makes an instance. + +So class is used to make +instances, meaning particular + +versions, of that structure, +and we said inside the + +instances we have a +set of attributes. + +Internal variables, methods, +that are going to belong to + +that structure. + +OK, so with that in mind, here's +what I want to do. + +I'm going to show you a set of +examples, and I want to warn + +you ahead of time, the code +handout today is a little + +longer than normal because we +want to build essentially an + +extended example of a sequence +of examples of classes. + +We're going to see the idea, +of which we're gonna talk + +about, of inheritance or +hierarchy, in which we can + +have classes that are + +specializations of other classes. + +We're gonna see how we can +inherit methods, how we can + +shadow methods, how we can use +methods in a variety of ways. + +So this is a way of suggesting +you may find it more + +convenient to put notes on the +code handout rather than in + +your own notes. + +Do whatever you like, but I +just wanted to alert you, + +we're going to go through a +little more code than normal. + +So, the little environment +I'm going to build is an + +environment of people. + +I'll build a simple little +simulation of people. + +So I'm going to start off with +the first class, which I've + +got up on the screen, and it's +on your handout as well, which + +is I'm going to build an +instance, or a class rather, + +of persons. + +I'm going to draw a diagram, +which I'm gonna try and see if + +I can do well, over here, of +the different objects we're + +going to have. So I've got, a +class, and by the way a class + +is an object. + +Instances are also objects, +but classes are objects. + +We're gonna see why we want +that in a second. + +Because I'm gonna build +an object, sorry a + +class, called a person. + +Now, let's walk through some +of the pieces here. + +The first one is, there's +something a little different. + +Remember last time we had that +keyword class and then a name, + +that name, in this case, person +says this is the name + +for the class, and then we +would have just had the + +semicolon and a bunch +of internal things. + +Here I've got something in +parens, and I want to stress + +this is not a variable. + +All right, this is not a +def, this is a class. + +I'm going to come back to it, +but what this is basically + +saying is that the person class +is going to inherit from + +another class, which in this +case is just the built-in + +Python object class. + +Hold on to that thought, it's +going to make more sense when + +we look at a little more +interesting example, but I + +want to highlight that. + +All right now, if we do this, +as I said before, we can + +create a version of a +person, let me just + +call it per, person. + +OK? + +And what we said last time is, +when we wanted to create an + +instance inside of this class +definition, we've got one of + +those built-in things +called init. + +I'm gonna again remind you, some +of the methods we have, + +Underbar underbar init is going +to be the thing that + +creates the instance. + +Actually slightly misspeaking, +actually Python creates the + +instance, but it's one thing +that fills it in. + +So in this case, I'm going to +give it 2 arguments: Frank + +Foobar Now, you might have said, +wait a minute, init here + +has 3 arguments: self, family +name, and first name. + +So again, just to remind you, +what we said happens here is + +that when I call this +class, person, + +I'm creating an instance. + +We'll draw a little instance +diagram down here. + +I'm going to give +it the name per. + +And I should have said inside +of person, we've + +got a set of things. + +We've got our underbar underbar +init, we've got, what + +else do I have up there? + +Family name. + +And a bunch of other methods, +down to say. + +What happens inside of Python +is, when we called the class + +definition, person, it creates +an instance, there it is. + +Think of it as a pointer to a +spot in memory, and then what + +we do is, we call, or find, that +init method, up here, and + +we apply it. + +And the first argument self, +points to the instance. + +So this object here is +what self looks at. + +Now you can see what +init's going to do. + +It says, oh, inside of self, +which is pointing to here, let + +me bind a variable, which was, +can read that very carefully, + +it's family underbar name, +to the value I passed + +in, which was 4. + +Same thing with first name. + +OK, so the reason I'm stressing +this is, self we do + +not supply explicitly, it is +supplied as pointing to the + +instance, it's giving us +that piece of memory. + +And that is what then +gets created. + +So here's, now, the +instance for per. + +OK, and I put a little label +on there, I'm going to call + +that an isALink, because it is +an instance of that class. + +God bless you. + +All right, so once we got this, +let's look at what we + +can do with person. + +That's why I built +person here. + +And as I said, I've +already bound + +basically, those two pieces. + +If I want to get a value out, +I can give person, or per, + +rather, this instance, +a messaging. + +In this case I want to get +family, what did I say, family + +name out, now, again I want to +stress, what is happening + +here? per is an instance, +it's this thing here. + +When I say per dot family +name, I'm sending it a + +message, in essence what that +does is, it says, from here + +it's going to go up the chain to +this class object and find + +the appropriate method, +which was family name. + +It is then going to apply +that to self, which + +points to this instance. + +And that allows it, therefore, +is you can see on the code, to + +look up under self, what's the +binding for family name, and + +print it back up. + +So self is always going to point +to the instance I want + +and I can use it. + +OK what else do we +have in here? + +We can get the first name, +that's not particularly + +interesting. + +We've got 2 other special +methods: that's cmp and str. + +All right, cmp is our +comparison method. + +And since I, I was about to +say I blew it last time, I + +misspoke last time, a wonderful +phrase that + +politicians like to use, +I misspoke last time. + +Let me clarify again +what cmp will do. + +Underbar underbar cmp is going +to be the method you're going + +to use to compare two instances +of an object. + +Now, let's back up for second. + +If I wanted to test equality, +in fact I could use underbar + +underbar eq, under under. + +It's natural to think about an +equality tester as returning a + +Boolean, it's either gonna +be true or false, because + +something's either +equal to or not. + +In many languages, comparisons +also return Booleans, which is + +why I went down this +slippery slope. + +For many languages, either it's +greater than or it's not. + +But Python is different. + +Python use cmp, in fact it has +a built in cmp, which is what + +we're relying on here. + +Where am I, right there. + +And what cmp returns +is 1 of 3 values. + +Given 2 objects, it says if the +first one is less than the + +second one, it returns -1, if +it's equal it returns 0, if + +it's greater than, +it returns 1. + +So it allows you this broader +range of comparisons. + +And if you think about it, +cmp, you could apply on + +integers, you could apply it on + +floats, apply it on strings. + +So it's overloaded, it has the +ability to do all of those. + +And in this case what we're +saying is, given 2 objects, + +let's create a tuple of the +first, sorry, family and first + +name of ourselves, and other is +another object, family and + +first name of that, and then +just use cmp to compare them. + +All right, so it's going +to use the base pieces. + +OK, so it gives me a way +of doing comparisons. + +And str we saw last time as +well, this is cmp does + +comparison, and str is our +printed representation. + +OK. + +So what we've got now, is +a simple little class. + +We've also got two +methods there. + +I want to look at them, we're +gonna come back to them, but + +they start to highlight things +we can do with our classes. + +So I've built one simple +version of it + +here, which is per. + +And notice I've got another +method, right up + +here, called say. + +And say takes two arguments, +for the moment the second + +argument, or the first +argument's, not going to make + +a lot of sense, but say takes +two arguments besides itself. + +It's going to take another +object to which it's saying + +something and the +thing to say. + +Since I only have one object +here, I'm going to have person + +talk to himself. + +You may have met a few +other undergraduates + +who have this behavior. + +I'll have him talk to himself +and say, just some random + +message the faculty members +occasionally worry about. + +OK, what does this thing do? + +Now you're going to see some +of the power of this. + +Again, remember, I'm down here, +I'm sending this the + +message say, it's going to go +up the chain to find the say + +message in person. + +And what does say do, it says +given another object and some + +string, it's going to return, +oh, and interesting things, + +part of which you can't +see on the screen. + +First what it does, is it +gets first name of self. + +Remember self is pointing to +this instance, so it's simply + +looks up that binding, +which is Frank. + +It's going to create a string +in which it adds to that the + +family name of self, and then +another thing that says to, + +and then ah, I'm now going to +send a message to the other + +object, saying give me +your first name. + +Going to add that to the second +piece, and you can see + +in this case it happens +to be the same + +first and family name. + +And then at the end of it, which +you can't see here but + +you can see in your handout, I +just append the whole string, + +so it spits it out. + +What's the point of this, +other than I can + +get it to say things? + +Notice, I can now reference +values of the instance. + +But I can also get values +of other instances, by + +sending in a message. + +And that's why we have that +form right there. + +And then it glued +all together. + +If you think about this for a +second, you might say, wait a + +minute, actually you might +have said wait a minute a + +while ago, why am I just using +the variable name there in the + +function over here? + +Well in fact, I could've used +the function here, first name + +open close, right? + +It would have done +the same thing. + +But because I know I'm inside +the instance, it's perfectly + +reasonable to just look +up the value. + +OK, I could have, although I +don't want you to do it, have + +done the same thing there and +used underbar, sorry, first + +name underbar, sorry, first +underbar name, but that's + +really breaking this contract +that I want to happen. + +I should send the message to +get the method back out. + +So again the standard practices +is if you know + +you're inside the object, you +can just access the values. + +If you're doing it with any +other objects, send it a + +message to get it out. + +OK, now, that gives you an +ability to say, let's look at + +one more example here, and +then we're going to start + +building our hierarchy, +which is, that this + +person can also sing. + +And we've got a little +sing method here. + +And notice what it does, it's +going to sing to somebody, I + +guess you're part of +the Chorallaries. + +You're going to sing something, +and notice what it + +does, it's simply going to use +its say method, but add at the + +end of whatever's being said, +just tra la la at the end. + +So this is now an example of a +method using another method. + +Why would you want that? + +It's nice modularly. + +I have one method that's doing +saying, I have another method + +that's just building on it. + +So if I have is person sing to +themselves, not a highly + +recommended activity, it would +help if I had it sing to + +itself, not sing to sing, +sorry about that. + +Notice what it does. + +Looks like exactly like a say +method, except it's got tra la + +la at the end. + +Don't worry I'm not going +to sing to you. + +I'll simply say the words. + +Power of this, other than +the silly examples. + +You see how I can access +variables of the instance, how + +I can access variables of other +instances, going to come + +back to that, and how I can use +versions of my own methods + +to implement other methods. + +In this case sing is using +say as part of what it + +wants to get out. + +OK, so we got a simple +little example. + +Now, let's start adding some +other pieces to this. + +OK, and what do I want to add. + +Find my spot here. + +OK, we're going to add +an MIT person. + +Sorry, machine is -- do +this, let's go down. + +OK so I'm going to add +an MIT person. + +Look at the code for second. + +Aha! + +Notice what this says. + +MIT person says it inherits +from person. + +That is, that's the first thing +in parens up there. + +It says, you know, class of +MIT person is person. + +What that is saying is, that +this is a specialization of + +the person class. + +Or another way of saying it is, +we have a super class, in + +this case it's person. + +And we have a subclass, in +this case its MIT person. + +And we're going to walk through +some examples, but + +what it says is that that +subclass of MIT person can + +inherit the attributes +of the person class. + +Can inherit the methods, it +can inherit variables. + +OK, what does MIT person do? + +Well, here's 1 of the +new things it does. + +It has a local variable called +next id num, which is + +initially set to 0. + +See that up there. + +And then it's got some methods, +it's got an init + +method, a get id method, +a few other things. + +OK, let's run this. + +In particular, I go back +down to this one. + +Let me just uncomment +this and do it here. + +Assuming my machine will do what +I want it to do, which it + +really doesn't seem to +want to do today. + +Try one more time. + +Thank you, yep. + +Still not doing it +for me, John. + +OK, we type it. + +No idea what Python doesn't like +me today, but it doesn't. + +So we're gonna define p 1, I've +lost my keyboard, indeed + +I have. Try one more time. p 1 +MIT person, see how fast I can + +type here -- + +OK, now, let's look at what the +code does, because again + +it's going to highlight +some things. + +I called MIT person, push this +up slightly, it's going to + +create an instance down +here, I called p 1. + +And when I would do that, +I'm gonna initialize it. + +So I've got, right up here, an +initializer, init for MIT + +person, takes in the family +name and the first name. + +Notice what it does. + +Huh. + +It says, if I'm sitting here at +MIT person, I'm going to go + +up and inherit from person its +init function and call it. + +And what am I calling it on? + +I'm calling it on self, which is +pointing to this object, so + +I've still got it, and then I'm +then going to apply the + +base initialization. + +And that does exactly what you'd +expect, which is just + +going to create a binding for +family name down here. + +As well as some other things. + +So this is an example +of inheritance. + +MIT person inherits the init +method from person, can get + +access to by simply referring +to it, and I + +refer to it right there. + +And it's take the person class, +get its init and apply + +it to my instance plus +those things. + +So I'm just using the +same piece of code + +Notice the second +thing it does. + +It says inside of self, I'm +going to bind the local + +variable id name to the value of +next id name in MIT person. + +Self is down here, id num, +sorry, not id name. + +I'm going to bind that to the +value that I find my going up + +to here, which is 0, and having +done that, I simply + +increment that value. + +OK? + +So what has this done? + +It says I now have captured in +the class, a local variable + +that I can keep track of. + +And when I use it, every time I +generate an example, let me + +build another one. + +I make p 2 another MIT person. + +OK, I can do things like saying, +what is the id number + +for each of these. + +First one is 0, second one is +1, which makes sense, right? + +I'm just incrementing +a global variable. + +Now, things I want you +to see about this. + +Now that I've got a beginning +of a hierarchy, I have this + +notion of inheritance. + +I can ask a function inside one +class to use a function + +from a class that it can reach +by going up the chain. + +I just did it there. + +I can ask it to go get values +of variables, right, so that + +looks good. + +What else do we have in +person or MIT person? + +Well, we can get the id +number, we just did. + +We have a thing to do +with this string. + +Notice it's going to print out +something a little different. + +In fact, there's a kind +of funky form there. + +Which just says, if I want to +print it out, I'm gonna + +create, what this says to do is, +I'm gonna create an output + +template that has that structure +to it, but where I + +see that percent s I'm going to +substitute this value for + +the first one, that value +for the second. + +So if I say, what is p 1? + +It says ok, MIT person +Fred Smith. + +On the other hand, if I said, +what is per, which is that + +thing I build earlier, it had +a different string method, + +which is just print out +person, those pieces. + +All right, one last piece +to this and we're + +going to add to it. + +Suppose I want Fred +to say something. + +Say something to Jane. + +OK, he said it. + +Where's the say method? + +OK, Fred is an instance +of an MIT person. + +where's the say method? + +Well, there isn't one there, +but again, that's where the + +hierarchy comes in. + +Fred is this object here, I'm +sending it the message say. + +That turns into going up the +chain to this object, which is + +the class object, and saying +find a say method and apply it + +to that instance. + +Fudge-knuckle, it ain't here. + +Don't worry about it, because +it says if I can't find one + +there, I'm going to go up the +chain to this method, sorry to + +this class, and look +for a method there. + +Which there was one, I +have a say method. + +It's going to use +that say method. + +Apply to it. + +Well, you might say, OK, what +happens if it isn't there? + +Well, that's where, remember +I defined person to be an + +instance of an object, it will +go up the chain one last time + +to the base object in Python +to see is there a + +method there or not. + +Probably isn't a say method +for an object, so at that + +point it's going to raise an +exception or throw an error. + +But now you again see this idea +that the inheritance lets + +you capture methods. + +Now you might say, why not just +put a say method inside + +of MIT person? + +Well, if you wanted it to do +something different, that + +would be the right +thing to do. + +But the whole notion here's that +I'm capturing modularity, + +I've got base methods +up in my base class. + +If I just want to use them I'm +just going to inherit them by + +following that chain, if you +like, basically up the track. + +OK, so we've got an MIT person, +we can use that. + +Let's add a little bit more +to our hierarchy here. + +I'm going to create, if +I can do this right, a + +specialization of an MIT +person, which is an + +undergraduate. + +A special kind of MIT person. + +All right, so if I go back up +here, even though my thing is + +not going to let me do it, let's +build an undergraduate. + +OK, there's the class definition +for an undergrad. + +We're just starting to see some +of the pieces, right, so + +in an undergraduate, where am +I here, an undergraduate. + +OK, it's also got an +initialization function. + +So if I call undergrad, I'm +gonna make an undergrad here, + +again let me go back down here, +line ug 2 it's making + +undergrad, Jane Doe. + +Now, what happens when I do +the initialization here? + +Notice what goes on. + +It simply calls the person +initialization method. + +All right, so I'm down here. + +I'm going to call the person +initialization + +method, what did do? + +Sorry, the MIT person method, +it calls the person method. + +Just walking up the chain, +that's going to do exactly + +what I did with all the other +ones, so I now have a family + +name and a first name. + +So I can, for example, +say family name + +and get it back out. + +All right? + +And then, other things that I +can do, well I can set what + +year the person's in, I can +figure out what year they're + +in, there's this unfortunate +overflow error if you've hung + +around too long, but that's not +going to happen to you. + +And I've now got a say method +here, so let's look what + +happens if I ask the + +undergraduate to say something. + +OK, it's not a realistic +dialogue I know, but, what did + +this method do? + +I asked this object +to do a say. + +And notice what it does. + +It simply passes it back +up to MIT person. + +There's that inheritance +again. + +It's saying, I'm going +to have my base + +say method say something. + +I'm going to say it to a person, +but all I'm going to + +do because undergraduates in my +experience, at least, are + +always very polite, I'm going to +put "Excuse me but" at the + +front of it. + +OK, what am I trying +to show you here? + +I know the jokes are awful, +but what am I + +trying to show you here? + +That I can simply pass up +the chain to get it. + +In fact, what method does +the final say here? + +What class does it come from? + +Person class, yes, thank you. + +It goes all the way up to +person, right, because MIT + +person didn't have a say. + +So I can simply walk up the +chain until I find the method + +I want to have. + +Now this is an example +of shadowing. + +Not a great example, but it's +a beginning example of + +shadowing, in that this same +method for an undergraduate, + +shadows the base say method, it +happens to call it, but it + +changes it. + +It puts "Excuse me but" at +the front, before it + +goes on to do something. + +Now again, I could have decided +here to actually copy + +what the original say method +did, stitch all the other + +things together. + +But again, that loses +my modularity. + +I'd really to only have to +change it in one place. + +So by putting my say method up +in person, I can add these + +nuances to it, and it lets +me have something + +that has that variation. + +If I decide I want to change +what say does, I only have to + +change it in one place. + +It is in the person class +definition, and everything + +else will follow through +for free. + +OK, so now I've got an +undergrad, right? + +Let's look at a couple +of variations of + +what happens here. + +So first of all, I can -- yes? + +PROFESSOR 2: Shadowing here +is often sometimes called + +overriding. + +PROFESSOR: Yes, thank you, +because I'm going to do a pure + +example of shadowing in +a second, John right. + +Also called overriding. + +Part of the reason I like the +phrase shadow is, if you think + +about it as looking at it from +this direction, you see this + +version of init before you see +the other ones, or you see + +that version of say, but +it is overriding + +the base say example. + +OK, so I can say, what does +p 1, sorry, yes, what does + +undergrad look like? + +And I said wait a minute, +MIT person, not + +undergrad, is that right? + +Well, where's the str method? + +I didn't define one in +undergrad, so it again tracks + +up the chain and finds the str +method here, so it's OK + +undergrads are MIT people +most the time, so + +it's perfectly fine. + +OK, now, I have built into this +also these cmp methods. + +So I've got two examples. + +I've got undergrad, or ug. + +And then I've got poor +old Frank Foobar + +back there, per person. + +So suppose I want +to compare them? + +What do you think +happens here? + +Compare sounds weird, +right, I compare an + +undergraduate to a person. + +I don't know what that's doing, +some kind of weird + +psychological thing, but what do +you think happens in terms + +of the code here +if I run this. + +I know it's a little hard +because you got a lot of code + +to look at. + +Do I have a cmp method +defined somewhere? + +Yeah. + +So, it's hard to know what it's +going to do, but let's + +look at it. + +Hmm. + +Now sometimes I type things +and I got errors I don't + +expect, this one I did expect. + +So what happened here? + +Well let's talk about what +happens if I do that + +comparison I was doing, +what was I doing? + +Ug greater than per? + +What unwinds into is, I'm going +to send to ug, that + +instance, a cmp method. + +This is really going to become +something like ug dot under + +under cmp under under +applied to per. + +I think that's close. + +What does that do? + +It says starting in ug, I'm +going to look for the first + +cmp method I could find, which +is actually sitting here. + +I had a cmp method +in MIT person. + +If you look at your code, +what does it do? + +It looks up the id numbers +to compare them. + +Well the, ug has an id number +because it was created along + +this chamber. + +Remember per over here was +just created as a person. + +It doesn't have an id number, +so that's why it complaints. + +Ok, happens if I do that? + +Compare per to ug. + +How many people think +I get an error? + +Wow. + +How many people think I'm going +to get either true or + +false out of this? + +A few brave hands. + +Why? + +Can I ask you, please? + +Why do you think I'm going to +get a, doesn't matter whether + +it's true or false, why am I +going to have something work + +this time that didn't +work last time? + +STUDENT: [INAUDIBLE] + +PROFESSOR: Yeah, exactly. + +And in case you didn't hear it, +thank you, great answer, + +sorry, terrible throw. + +In this case I'm using per, +that's the first part, so it's + +not symmetric. + +It's gonna use per to +do the look up. + +And as it was said there, per +over here goes up and finds a + +cmp method here which +it can apply. + +In that case, it simply looked +at, remember, it took the + +tuples of first and last name +which are both defined here, + +and did some comparison +on that. + +So this is a way of again +pointing out to you that the + +things are not always symmetric, +and I have to be + +careful about where do +I find the methods as + +I want to use them. + +Ok? + +All right. + +Let's add, I'm gonna do +two more classes here. + +Let's add one more class, some +people debate whether these + +are really people or not, but +we're going to add a class + +called a professor. + +OK. + +Now what am I doing? + +I'm creating another version +of class down here. + +Which again is an instance, or +a subclass, sorry, not an + +instance, a subclass +of an MIT person. + +I see that because I built +it to be there. + +Again I've got an initialization +that's going to + +call the person initialization, +which we know + +is going to go up -- + +I keep saying that -- going +to call the MIT person + +initialization, which is going +to go up and call this one. + +So again I'm going to be +able to find names. + +And I do a couple of other +different things here. + +I'm gonna pass in a rank, full +professor, associate + +professor, assistant professor, +which I'm just + +going to bind locally. + +But I'm gonna add one other +piece here, which is I'm gonna + +add a little dictionary +on teaching. + +So when I create a professor, +I'm gonna associate with it a + +dictionary that says, what +have you been teaching? + +And then notice the +methods I create. + +I've got a method here called +add teaching, takes, obviously + +a pointer to the instance. + +A term, which will just be +a string, and a subject. + +And let's look at what +it does right here. + +OK. + +In fact the call I'm going to +make, I'm not certain I'm + +going to be able to get away +with it, my machine is still + +wonderfully broken, all right, +it is, let me just show you + +what the calls would +look like. + +As you can see here I'm not +going to be able to do them. + +But I'm going to add teaching, +as a method call with this + +with a string for term, +and a subject number. + +What is this going to do? + +Yeah, I know I'm just worried if +I restart Python, I may not + +be able to pull the thing back +in, so I'm going to try and + +wing it, John, and see if +I can make it happen. + +Right, what does that +teaching do? + +It's got one of those +try except methods. + +So what does it say +it's going to do? + +It's going to go into the +dictionary associated with + +teaching, under the value of +term, and get out a list. And + +it's going to append +to the end of the + +list the new subject. + +So it's going to be stored in +there, is then going to be + +term, and a list of what I +taught, in case I teach more + +than one thing each term. + +It's going to do that, but +notice it's a try. + +If in fact there is no term +currently in the dictionary, + +started out empty, it's going to +throw an error, sorry, not + +throw an error, it's going +to raise an exception. + +Which is a key error, in which +case notice what I'm going to + +do, I'm not going to treat +it as an error. + +I'm simply going to say, in that +case, just start off with + +an empty, with an initial list +with just that subject in and + +put it in the dictionary. + +As I add more things in, I'll +just keep adding things to + +this dictionary under +that term. + +And if I want to find out what +I'm doing, well I can use get + +teaching, which says given the +term, find the thing in the + +dictionary under that +term and return it. + +If I get an error, I'm going to +raise it, which says there + +is nothing for that term, and in +that case I guess I'm just + +going to return none. + +OK? + +And then the other two pieces +we're going to have here, and + +we want to look at a little more +carefully, I just wanted + +to show you that example, is a +professor can lecture, and a + +professor can say something. + +Look at the say method, because +this now add one more + +nuance to what we +want to do here. + +And I think in interest of +making this go, let me + +actually, since I'm not going +to get my machine to do this + +right, let me create a +couple of professors. + +If I look at what that is, it's +an MIT person because I + +didn't have any separate string +thing there, and we + +will create a more important +professor. + +What rank do you want, John? + +Do you want to stay full? + +PROFESSOR 2: Undergraduate. + +PROFESSOR: Undergraduate, right, +a lot more fun I agree. + +Sorry about that, and we +can again just see + +what that looks like. + +And that of course, +we'll print out, + +he's also an MIT person. + +But now here's what +I want to do. + +I want to say something +to my good + +colleague Professor Guttag. + +Actually I'm going to +start a separate -- + +I'm going to say something +to a smart undergraduate. + +So if I say, remember we +have ug defined as an + +undergraduate, let +me do something a + +little different here. + +Well let, me do it that way. + +It says, I don't understand +why you say you + +were enjoying 6.00. + +Not a good thing to say, right, +but if I say to my good + +colleague Professor Guttag. + +I have to spell say right, I +know, I need help with this, + +what can I say? + +We flatter each other +all the time. + +It's part of what makes us feel +good about ourselves. + +Why is the sky blue? + +I enjoyed your paper, but +why is the sky blue? + +OK, terrible examples, but +what's going on here? + +One more piece that +I want to add. + +Here's my say method for +professor, and now I'm + +actually taking advantage of to +whom I am saying something. + +Notice again, what does it do? + +There's the self argument, +that's just pointing to the + +instance of me. + +I'm passing in another argument, +going to call it to + +who, in one case it was ug, +in one case it was Guttag. + +And then the thing I want to +say, ah, look what it does, it + +says, check the type. + +And the type is going to take +that instance, I had an + +instance, for example, of a +professor down here, and it's + +going to pick up what type +of object it is. + +So if the type of the person I'm +speaking to is undergrad, + +let's pause for second. + +Remember I started away back +saying we're building abstract + +data types. + +Well, here's a great example +of how I'm using + +exactly that, right? + +I've got int, I've got float, +I now have ug, it's a type. + +So it's says if the object to +whom I'm speaking is an + +undergrad, then use the same +method from person where I'm + +going to put this +on the front. + +On the other hand, if the object +to whom I'm speaking is + +a professor, then I'm going to +tag this on the front and use + +the underlying say method. + +On the other hand, if I'm +speaking to somebody else, I'm + +just going to go lecture. + +All right, and when a professor +lectures, they just + +put it's obvious on the +end of things, as + +you may have noticed. + +What's the point I want +you to see here? + +I'm now using the instances +to help me to find what + +the code should do. + +I'm looking at the type. + +If the type is this, do that. + +If the type is this, do +something different, ok? + +And I can now sort of build +those pieces up. + +OK, I said one more class. + +Notice what we're doing. + +I know they're silly examples, +but, sorry, they are cleverly + +designed examples to highlight +key points. + +What I'm trying to do is show +you how we have methods + +inherit methods, how have +message shadow methods, how we + +have methods override methods, +how we can use instances as + +types to define what the +method should do. + +Let me show you one last class, +because I'm gonna have + +one more piece that +we want to use. + +And the last class is, sort of, +once you've got a set of + +professors, you can have +an aggregate of them. + +And I don't know, if a group of +geese are gaggle, I don't + +know what a set of professors +are, John. + +Flamers? + +I, you know, we've got to figure +out what the right + +collective noun here is. + +We're going to call them a +faculty for lack of a better + +term, right? + +Now the reason I want to show +you this example is, this + +class, notice, it only is going +to inherit from object. + +It actually makes sense. + +This is going to be a collection +of things, but it's + +not a subclass of a particular +kind of person. + +And what I want the faculty to +do, is to be able to gather + +together a set of faculty. + +So if I go down here, grab this +for second, and pull it + +down so you can see it. + +It looks like I'm not going to +be able to run this because my + +machine is broken, but basically +I'm gonna define a + +set of professors, and then I'm +gonna create a new class + +called faculty. + +There's the definition of it. + +It's got an init. + +You can kind of see +what it does. + +It's going to set up an internal +variable called + +names, which is initially an +empty list, internal variable + +called ids, which is empty, an +internal variable called + +members, which is empty, and +another special variable + +called place, which we're going +to come back to in a + +second, initially +bound to none. + +OK, I've got a method called +add which I'm going to use + +down here to add professors +to the course 6 faculty. + +Here's what I want +to add to do. + +First of all, notice I'm going +to check the type. + +If this is not a professor, I'm +gonna raise an error, a + +type error, it's the wrong type +of object to pass in. + +The second thing I'm gonna do +is say, if that's okay, then + +let me go off and get +the id number. + +Now remember, that's right up +here, so I'm asking the + +instance of the professor to go +up and get the id number. + +And I want to make sure I only +have one instance of each + +professor in my faculty, so if +the id number is in the list + +of ids already, I'm going to +raise an error, sorry, raise + +an exception as well, saying +I've got a duplicate id. + +OK? + +And the reason that's +going to come up is, + +notice what I do now. + +Inside of the instant self, I +take the variable names and I + +add to it the family name of +the person I just added. + +OK, notice the form. + +I'm using the method, there's +the parens to get the family + +name of the person. + +I'm just adding it to the list. +I've got the id number, + +I've added the ids, +and I add the + +object itself into members. + +So as I do this, what +am I doing? + +I'm creating a list, actually +several lists: a list of ids, + +a list of the actual instances, +and a list of the + +family names. + +And as a cost I want to add, +that's why I can check and + +see, is this in here +already or not? + +Now, the last reason I want to +do this is, I want to be able + +to support things like that. + +This is now different, right, +this instance is a collection. + +I want to be able to do things +like, for all the things in + +that collection, do something, +like print + +out the family names. + +And to do that, I need two +special forms: iter and next. + +OK, now let me see if I +can say this cleanly. + +Whenever I use a for, in +structure, even if it was on + +just a normal list you built, +what Python is doing is + +returning an, what is +called an iterator. + +Which is something that +we talked earlier. + +It's keeping track of where are +you in the list, and how + +do I get to the next +thing in the list? + +I'm going to do the same thing +here, and I'm going to create + +it for this particular +structure. + +So this little thing iter, when +I call a for something + +in, one of these instances, +it calls iter, and + +notice what it does. + +It initializes place to 0. + +That was that variable +I had up there. + +That's basically saying I'm at +the beginning of the list. + +It's a pointer to the beginning +of the list, and it + +returns self. + +Just gives me back a pointer +to the instance. + +That now allows me at +each step in that + +loop to call next. + +And what does next do? + +Next says, check to see if that +value is too long, if + +it's longer than, for example, +the list of names, raise an + +exception called stop iteration, +which the for loop + +will use to say OK, I'm done. + +I'm going to break out +of the for loop. + +Otherwise, what am +I going to do? + +I'll increment place by 1, +that's going to move me to the + +next place in the list, and then +in this case I'll just + +return the instance +itself, right? + +Members is a list of instances, +place I've + +incremented by 1, I take 1 +off of it, I get to it. + +So iter and next +work together. + +Iter creates this method, that's +going to give you a + +pointer to the place in the +structure, and then next + +literally walks along the +structure giving you the next + +element and returning elements +in turn so you can do + +something with it. + +Right, so now what that says +is, I can have classes that + +just have local variables. + +I can have classes that get +methods from other variables, + +and I can also have classes +that are collections. + +And I've supported that by +adding in this last piece. + +OK once you have all of that, +in principle we could start + +doing some fun things. + +So let's see what happens +if we try and + +make all of this go. + +And let me, since I'm not going +to be able to run it, + +let me simply do it this way. + +If I have my undergraduate, +ug. + +I can -- sorry, let's not +do it that way -- + +I can have undergraduate say +things like -- all right, what + +did I just do wrong here? + +Do I not have undergrad +defined? + +I do. + +Oh, I didn't have Grimson, +sorry, it's me, isn't it? + +Thank you. + +The undergraduate very politely +asks why he didn't + +understand, you can have +the professor respond. + +Again, it simply puts a +different thing into there. + +On the other hand, if Professor +Guttag asks me + +something about understanding, I +say I really like this paper + +on, you do not understand, +it's a deep paper on + +programming languages 5, I +think, John, isn't it? + +What else can you do with +this thing, right? + +You can have an undergraduate +talk to an undergraduate, in + +which case they're +still polite. + +Or you could have -- sorry, let +me do that the other way + +-- you could also have an +undergraduate simply talk to a + +normal person. + +All right, but the good news is +you know eventually you get + +it done, and when you're really +done you can have the + +undergraduate be really happy +about this, and so she sings + +to herself. + +OK it's a little silly, but +notice what we've just + +illustrated. + +And this is where I want +to pull it together. + +With a simple set of classes, +and the following abilities, + +an ability to inherit methods +from subclasses, sorry from + +superclasses, that is having +this hierarchy of things. + +I can create a fairly complex +kind of interaction. + +I can take advantage of the +types of the objects to help + +me decide what to do. + +And if you think about that, +I know it sounds very + +straightforward, but you would +do exactly that if you were + +writing earlier code to deal +with some numerical problem. + +All right, if the thing is an +integer, do this, if it's a + +float, do that, if it's a +string, do something else. + +I'm now giving you exactly the +same ability, but the types + +now can be things that +you could create. + +And what I've also got is now +the ability to inherit those + +methods as they go +up the chain. + +So another way of saying it is, +things that you want to + +come away from here, are, in +terms of these classes. + +We now have this idea +of encapsulation. + +I'm gathering together data that +naturally belongs as a + +unit, and I'm gathering together +with it methods that + +apply to that unit. + +Just like we would have done +with float or int. + +Ideally, we data hide, we don't +happen to do it here, + +which is too bad. + +Basically we've got the +idea of encapsulation. + +The second thing we've got is +this idea of inheritance. + +Inheritance both meaning +I can inherit + +attributes or field values. + +I can inherit methods by +moving up the chain. + +I can also the shadow or +override methods, so that I + +can specialise. + +And I do all of that with this +nice hierarchy of classes. + +So what hopefully you've seen, +between these two lectures, + +and we're going to come back +to it in some subsequent + +lectures, is that this is now +a different way of just + +structuring a computational +system. + +Now, you'll also get arguments, +polite arguments + +from faculty members or other +experts about which is a + +better way of doing it. + +So I'll give you my bias, +Professor Guttag will give you + +his bias next time around. + +My view, object-oriented system +are great when you're + +trying to model systems that +consist of a large number of + +units that interact in +very specific ways. + +So, modeling a system of +people's a great idea. + +Modeling a system of molecules +is probably a great idea. + +Modeling a system where it is +natural to associate things + +together and where the number +of interactions between them + +is very controlled. + +These systems work +really well. + +And we'll see some examples +of that next week. + +Thanks. \ No newline at end of file diff --git a/QkyiiMUYH2U.txt b/QkyiiMUYH2U.txt new file mode 100644 index 0000000000000000000000000000000000000000..07246562dfae4bf3da309496397a4341d1b1a291 --- /dev/null +++ b/QkyiiMUYH2U.txt @@ -0,0 +1,10931 @@ +align:start position:0% + +I hope that without the coffee you can + + align:start position:0% +I hope that without the coffee you can + + + align:start position:0% +I hope that without the coffee you can +still stay awake for uh the next 90 + + align:start position:0% +still stay awake for uh the next 90 + + + align:start position:0% +still stay awake for uh the next 90 +minutes especially the first 45 is going + + align:start position:0% +minutes especially the first 45 is going + + + align:start position:0% +minutes especially the first 45 is going +to be mine and I'm going to take it very + + align:start position:0% +to be mine and I'm going to take it very + + + align:start position:0% +to be mine and I'm going to take it very +personally if all deep so please don't + + align:start position:0% +personally if all deep so please don't + + + align:start position:0% +personally if all deep so please don't +do it um so in the first part of the + + align:start position:0% +do it um so in the first part of the + + + align:start position:0% +do it um so in the first part of the +course we've been talking a lot about + + align:start position:0% +course we've been talking a lot about + + + align:start position:0% +course we've been talking a lot about +mitigation basically how do we make + + align:start position:0% +mitigation basically how do we make + + + align:start position:0% +mitigation basically how do we make +investments in the build environment and + + align:start position:0% +investments in the build environment and + + + align:start position:0% +investments in the build environment and +how do we understand the business case + + align:start position:0% +how do we understand the business case + + + align:start position:0% +how do we understand the business case +of reducing emissions uh to reduce uh + + align:start position:0% +of reducing emissions uh to reduce uh + + + align:start position:0% +of reducing emissions uh to reduce uh +the chances of suffering climate change + + align:start position:0% +the chances of suffering climate change + + + align:start position:0% +the chances of suffering climate change +climate disasters and so forth that's + + align:start position:0% +climate disasters and so forth that's + + + align:start position:0% +climate disasters and so forth that's +been the whole first part of the of the + + align:start position:0% +been the whole first part of the of the + + + align:start position:0% +been the whole first part of the of the +block brainwashing you into emissions + + align:start position:0% +block brainwashing you into emissions + + + align:start position:0% +block brainwashing you into emissions +are bad don't do it is actually + + align:start position:0% +are bad don't do it is actually + + + align:start position:0% +are bad don't do it is actually +profitable if you do it in a proper way + + align:start position:0% +profitable if you do it in a proper way + + + align:start position:0% +profitable if you do it in a proper way +so please uh take action that's the + + align:start position:0% +so please uh take action that's the + + + align:start position:0% +so please uh take action that's the +first part now we're going to have three + + align:start position:0% +first part now we're going to have three + + + align:start position:0% +first part now we're going to have three +sessions into the consequences of + + align:start position:0% +sessions into the consequences of + + + align:start position:0% +sessions into the consequences of +climate change so once we put a lot of + + align:start position:0% +climate change so once we put a lot of + + + align:start position:0% +climate change so once we put a lot of +these emissions in the atmosphere a lot + + align:start position:0% +these emissions in the atmosphere a lot + + + align:start position:0% +these emissions in the atmosphere a lot +of we increase the likelihood of a lot + + align:start position:0% +of we increase the likelihood of a lot + + + align:start position:0% +of we increase the likelihood of a lot +of St bad stuffff to happen and we are + + align:start position:0% +of St bad stuffff to happen and we are + + + align:start position:0% +of St bad stuffff to happen and we are +going to learn what are the consequences + + align:start position:0% +going to learn what are the consequences + + + align:start position:0% +going to learn what are the consequences +for real estate markets we're going to + + align:start position:0% +for real estate markets we're going to + + + align:start position:0% +for real estate markets we're going to +do this in terms of what are the + + align:start position:0% +do this in terms of what are the + + + align:start position:0% +do this in terms of what are the +consequences for Real Estate Value real + + align:start position:0% +consequences for Real Estate Value real + + + align:start position:0% +consequences for Real Estate Value real +estate prices we are going to talk about + + align:start position:0% +estate prices we are going to talk about + + + align:start position:0% +estate prices we are going to talk about +the basics of climate science and we're + + align:start position:0% +the basics of climate science and we're + + + align:start position:0% +the basics of climate science and we're +going to start thinking about how to + + align:start position:0% +going to start thinking about how to + + + align:start position:0% +going to start thinking about how to +adapt and how to make resiliency uh + + align:start position:0% +adapt and how to make resiliency uh + + + align:start position:0% +adapt and how to make resiliency uh +investments into the buildt environment + + align:start position:0% +investments into the buildt environment + + + align:start position:0% +investments into the buildt environment +so three sessions today Thursday and + + align:start position:0% +so three sessions today Thursday and + + + align:start position:0% +so three sessions today Thursday and +Tuesday we are going to be very uh deep + + align:start position:0% +Tuesday we are going to be very uh deep + + + align:start position:0% +Tuesday we are going to be very uh deep +into that topic onto how real estate + + align:start position:0% +into that topic onto how real estate + + + align:start position:0% +into that topic onto how real estate +assets how real estate markets how Real + + align:start position:0% +assets how real estate markets how Real + + + align:start position:0% +assets how real estate markets how Real +Estate Investors are impacted by climate + + align:start position:0% +Estate Investors are impacted by climate + + + align:start position:0% +Estate Investors are impacted by climate +risk and climate uh disasters we are + + align:start position:0% +risk and climate uh disasters we are + + + align:start position:0% +risk and climate uh disasters we are +going to do it with the usual suspects + + align:start position:0% +going to do it with the usual suspects + + + align:start position:0% +going to do it with the usual suspects +CI and me are going to be here in front + + align:start position:0% +CI and me are going to be here in front + + + align:start position:0% +CI and me are going to be here in front +of you uh but we are also going to have + + align:start position:0% +of you uh but we are also going to have + + + align:start position:0% +of you uh but we are also going to have +a industry leaders that are will to come + + align:start position:0% +a industry leaders that are will to come + + + align:start position:0% +a industry leaders that are will to come +here to see how actually the action is + + align:start position:0% +here to see how actually the action is + + + align:start position:0% +here to see how actually the action is +being taken on the ground in the in the + + align:start position:0% +being taken on the ground in the in the + + + align:start position:0% +being taken on the ground in the in the +sector today h I'm going to talk for the + + align:start position:0% +sector today h I'm going to talk for the + + + align:start position:0% +sector today h I'm going to talk for the +first half but the second half is going + + align:start position:0% +first half but the second half is going + + + align:start position:0% +first half but the second half is going +to be by Kevin fan who was sitting here + + align:start position:0% +to be by Kevin fan who was sitting here + + + align:start position:0% +to be by Kevin fan who was sitting here +12 years ago 13 13 years ago Ms alarm + + align:start position:0% +12 years ago 13 13 years ago Ms alarm + + + align:start position:0% +12 years ago 13 13 years ago Ms alarm +that went one day to New York he was + + align:start position:0% +that went one day to New York he was + + + align:start position:0% +that went one day to New York he was +telling me and got an offer after one + + align:start position:0% +telling me and got an offer after one + + + align:start position:0% +telling me and got an offer after one +hour and a half interview and was good + + align:start position:0% +hour and a half interview and was good + + + align:start position:0% +hour and a half interview and was good +enough to keep him for 12 years he's at + + align:start position:0% +enough to keep him for 12 years he's at + + + align:start position:0% +enough to keep him for 12 years he's at +moodies the head of the CR unit there + + align:start position:0% +moodies the head of the CR unit there + + + align:start position:0% +moodies the head of the CR unit there +after being for many years in the + + align:start position:0% +after being for many years in the + + + align:start position:0% +after being for many years in the +climate in the in the credit risk uh + + align:start position:0% +climate in the in the credit risk uh + + + align:start position:0% +climate in the in the credit risk uh +Department one of the people that I + + align:start position:0% +Department one of the people that I + + + align:start position:0% +Department one of the people that I +encountered that knows the most about + + align:start position:0% +encountered that knows the most about + + + align:start position:0% +encountered that knows the most about +climate change climate risk also + + align:start position:0% +climate change climate risk also + + + align:start position:0% +climate change climate risk also +transition risk and uh real estate so if + + align:start position:0% +transition risk and uh real estate so if + + + align:start position:0% +transition risk and uh real estate so if +you want to learn about that he's one of + + align:start position:0% +you want to learn about that he's one of + + + align:start position:0% +you want to learn about that he's one of +the best people in the world to do it + + align:start position:0% +the best people in the world to do it + + + align:start position:0% +the best people in the world to do it +and he's going to be with us the whole + + align:start position:0% +and he's going to be with us the whole + + + align:start position:0% +and he's going to be with us the whole +day we do this lecture and also a + + align:start position:0% +day we do this lecture and also a + + + align:start position:0% +day we do this lecture and also a +reception afterwards so please come + + align:start position:0% +reception afterwards so please come + + + align:start position:0% +reception afterwards so please come +enjoy the coffee but also make sure that + + align:start position:0% +enjoy the coffee but also make sure that + + + align:start position:0% +enjoy the coffee but also make sure that +you talk to Kevin because he's one of + + align:start position:0% +you talk to Kevin because he's one of + + + align:start position:0% +you talk to Kevin because he's one of +the people that you can learn the most + + align:start position:0% +the people that you can learn the most + + + align:start position:0% +the people that you can learn the most +much more than with me but I'm you know + + align:start position:0% +much more than with me but I'm you know + + + align:start position:0% +much more than with me but I'm you know +you guys have tra with me what can you + + align:start position:0% +you guys have tra with me what can you + + + align:start position:0% +you guys have tra with me what can you +say um so let me give you a little bit + + align:start position:0% +say um so let me give you a little bit + + + align:start position:0% +say um so let me give you a little bit +of you see bad and good bad Brown + + align:start position:0% +of you see bad and good bad Brown + + + align:start position:0% +of you see bad and good bad Brown +buildings polluting bad okay so let me + + align:start position:0% +buildings polluting bad okay so let me + + + align:start position:0% +buildings polluting bad okay so let me +give you a little bit of a of an outline + + align:start position:0% +give you a little bit of a of an outline + + + align:start position:0% +give you a little bit of a of an outline +for today's lecture or at least for for + + align:start position:0% +for today's lecture or at least for for + + + align:start position:0% +for today's lecture or at least for for +my part we are going to talk about the + + align:start position:0% +my part we are going to talk about the + + + align:start position:0% +my part we are going to talk about the +basics of climates uh change and the + + align:start position:0% +basics of climates uh change and the + + + align:start position:0% +basics of climates uh change and the +idea is to give you the logic of what it + + align:start position:0% +idea is to give you the logic of what it + + + align:start position:0% +idea is to give you the logic of what it +is and how that is actually going to be + + align:start position:0% +is and how that is actually going to be + + + align:start position:0% +is and how that is actually going to be +here to stay and how actually climate + + align:start position:0% +here to stay and how actually climate + + + align:start position:0% +here to stay and how actually climate +scientists are talking about it and + + align:start position:0% +scientists are talking about it and + + + align:start position:0% +scientists are talking about it and +discussing about climate change and and + + align:start position:0% +discussing about climate change and and + + + align:start position:0% +discussing about climate change and and +change in climate in a way that is + + align:start position:0% +change in climate in a way that is + + + align:start position:0% +change in climate in a way that is +useful to understand how that will + + align:start position:0% +useful to understand how that will + + + align:start position:0% +useful to understand how that will +impact the build environment and and + + align:start position:0% +impact the build environment and and + + + align:start position:0% +impact the build environment and and +real estate uh markets so I'm not going + + align:start position:0% +real estate uh markets so I'm not going + + + align:start position:0% +real estate uh markets so I'm not going +to give you a very thorough uh + + align:start position:0% +to give you a very thorough uh + + + align:start position:0% +to give you a very thorough uh +discussion around deep science but just + + align:start position:0% +discussion around deep science but just + + + align:start position:0% +discussion around deep science but just +enough for you to understand what you + + align:start position:0% +enough for you to understand what you + + + align:start position:0% +enough for you to understand what you +are talking about and what for you to + + align:start position:0% +are talking about and what for you to + + + align:start position:0% +are talking about and what for you to +understand that when the United Nations + + align:start position:0% +understand that when the United Nations + + + align:start position:0% +understand that when the United Nations +comes out and puts out a uh the next + + align:start position:0% +comes out and puts out a uh the next + + + align:start position:0% +comes out and puts out a uh the next +report how that affects your investment + + align:start position:0% +report how that affects your investment + + + align:start position:0% +report how that affects your investment +your Holdings or your decision in the + + align:start position:0% +your Holdings or your decision in the + + + align:start position:0% +your Holdings or your decision in the +real estate market then we're going to + + align:start position:0% +real estate market then we're going to + + + align:start position:0% +real estate market then we're going to +get into the the the nuts and balls of + + align:start position:0% +get into the the the nuts and balls of + + + align:start position:0% +get into the the the nuts and balls of +this in the real estate market using the + + align:start position:0% +this in the real estate market using the + + + align:start position:0% +this in the real estate market using the +for Quadrant model I've been casting a + + align:start position:0% +for Quadrant model I've been casting a + + + align:start position:0% +for Quadrant model I've been casting a +little bit around and there are some + + align:start position:0% +little bit around and there are some + + + align:start position:0% +little bit around and there are some +people that are more nervous and other + + align:start position:0% +people that are more nervous and other + + + align:start position:0% +people that are more nervous and other +people are less nervous about four + + align:start position:0% +people are less nervous about four + + + align:start position:0% +people are less nervous about four +quadrant models and so for more so we + + align:start position:0% +quadrant models and so for more so we + + + align:start position:0% +quadrant models and so for more so we +are going to undust that toolbox to + + align:start position:0% +are going to undust that toolbox to + + + align:start position:0% +are going to undust that toolbox to +understand actually how when one side of + + align:start position:0% +understand actually how when one side of + + + align:start position:0% +understand actually how when one side of +the market is impacted how it's going to + + align:start position:0% +the market is impacted how it's going to + + + align:start position:0% +the market is impacted how it's going to +be impacting the the whole Market as a + + align:start position:0% +be impacting the the whole Market as a + + + align:start position:0% +be impacting the the whole Market as a +whole all the stakeholders um and then + + align:start position:0% +whole all the stakeholders um and then + + + align:start position:0% +whole all the stakeholders um and then +we're are going to talk about more + + align:start position:0% +we're are going to talk about more + + + align:start position:0% +we're are going to talk about more +empirical assessments of climate risk + + align:start position:0% +empirical assessments of climate risk + + + align:start position:0% +empirical assessments of climate risk +and so forth so we're going to connect + + align:start position:0% +and so forth so we're going to connect + + + align:start position:0% +and so forth so we're going to connect +it to a lot of the tools that we cover + + align:start position:0% +it to a lot of the tools that we cover + + + align:start position:0% +it to a lot of the tools that we cover +in in these uh settings and a big part + + align:start position:0% +in in these uh settings and a big part + + + align:start position:0% +in in these uh settings and a big part +of this is going to be when we are + + align:start position:0% +of this is going to be when we are + + + align:start position:0% +of this is going to be when we are +thinking about DCS or we are thinking + + align:start position:0% +thinking about DCS or we are thinking + + + align:start position:0% +thinking about DCS or we are thinking +about assessing climate is going to be + + align:start position:0% +about assessing climate is going to be + + + align:start position:0% +about assessing climate is going to be +about about the discount rate that we're + + align:start position:0% +about about the discount rate that we're + + + align:start position:0% +about about the discount rate that we're +going to assess to that how the cap rate + + align:start position:0% +going to assess to that how the cap rate + + + align:start position:0% +going to assess to that how the cap rate +how a lot of the risk measures that are + + align:start position:0% +how a lot of the risk measures that are + + + align:start position:0% +how a lot of the risk measures that are +impacted are are introduced into these + + align:start position:0% +impacted are are introduced into these + + + align:start position:0% +impacted are are introduced into these +valuations are going to be affected by + + align:start position:0% +valuations are going to be affected by + + + align:start position:0% +valuations are going to be affected by +by climate RIS so this is going to be a + + align:start position:0% +by climate RIS so this is going to be a + + + align:start position:0% +by climate RIS so this is going to be a +big discussion into what what is + + align:start position:0% +big discussion into what what is + + + align:start position:0% +big discussion into what what is +appropriate to Discount climate risk and + + align:start position:0% +appropriate to Discount climate risk and + + + align:start position:0% +appropriate to Discount climate risk and +so forth it's going to be today on + + align:start position:0% +so forth it's going to be today on + + + align:start position:0% +so forth it's going to be today on +Thursday we're going to cover a lot of + + align:start position:0% +Thursday we're going to cover a lot of + + + align:start position:0% +Thursday we're going to cover a lot of +this and C we're going to cover also the + + align:start position:0% +this and C we're going to cover also the + + + align:start position:0% +this and C we're going to cover also the +role of beliefs in all of these the RO + + align:start position:0% +role of beliefs in all of these the RO + + + align:start position:0% +role of beliefs in all of these the RO +of climate beliefs and also the role of + + align:start position:0% +of climate beliefs and also the role of + + + align:start position:0% +of climate beliefs and also the role of +uh the differences between commercial + + align:start position:0% +uh the differences between commercial + + + align:start position:0% +uh the differences between commercial +and residential real estate markets for + + align:start position:0% +and residential real estate markets for + + + align:start position:0% +and residential real estate markets for +everyone to see so some Basics basically + + align:start position:0% +everyone to see so some Basics basically + + + align:start position:0% +everyone to see so some Basics basically +this is what happens with climate change + + align:start position:0% +this is what happens with climate change + + + align:start position:0% +this is what happens with climate change +we are emitting a lot of CO2 all those + + align:start position:0% +we are emitting a lot of CO2 all those + + + align:start position:0% +we are emitting a lot of CO2 all those +things that we are uh saying that you + + align:start position:0% +things that we are uh saying that you + + + align:start position:0% +things that we are uh saying that you +shouldn't do and we should reduce in the + + align:start position:0% +shouldn't do and we should reduce in the + + + align:start position:0% +shouldn't do and we should reduce in the +build environment once we put a unit of + + align:start position:0% +build environment once we put a unit of + + + align:start position:0% +build environment once we put a unit of +CO2 in the out there by burning uh fuel + + align:start position:0% +CO2 in the out there by burning uh fuel + + + align:start position:0% +CO2 in the out there by burning uh fuel +that sticks into the atmosphere and it + + align:start position:0% +that sticks into the atmosphere and it + + + align:start position:0% +that sticks into the atmosphere and it +prevents the radiancy of the the the + + align:start position:0% +prevents the radiancy of the the the + + + align:start position:0% +prevents the radiancy of the the the +radian power of of sun to go back into + + align:start position:0% +radian power of of sun to go back into + + + align:start position:0% +radian power of of sun to go back into +the universe and basically get stra + + align:start position:0% +the universe and basically get stra + + + align:start position:0% +the universe and basically get stra +warming the the planet and warm in the + + align:start position:0% +warming the the planet and warm in the + + + align:start position:0% +warming the the planet and warm in the +atmosphere that's a very basic thing + + align:start position:0% +atmosphere that's a very basic thing + + + align:start position:0% +atmosphere that's a very basic thing +every time that we put an extra unit of + + align:start position:0% +every time that we put an extra unit of + + + align:start position:0% +every time that we put an extra unit of +uh CO2 in the atmosphere we create an + + align:start position:0% +uh CO2 in the atmosphere we create an + + + align:start position:0% +uh CO2 in the atmosphere we create an +extra layer out there that prevents the + + align:start position:0% +extra layer out there that prevents the + + + align:start position:0% +extra layer out there that prevents the +sun to go to come out into the universe + + align:start position:0% +sun to go to come out into the universe + + + align:start position:0% +sun to go to come out into the universe +and keeps warming up the planet and what + + align:start position:0% +and keeps warming up the planet and what + + + align:start position:0% +and keeps warming up the planet and what +happens with climate change and and and + + align:start position:0% +happens with climate change and and and + + + align:start position:0% +happens with climate change and and and +the whole discussion is that CO2 is + + align:start position:0% +the whole discussion is that CO2 is + + + align:start position:0% +the whole discussion is that CO2 is +nothing new it's nothing that we create + + align:start position:0% +nothing new it's nothing that we create + + + align:start position:0% +nothing new it's nothing that we create +as humans is is there in the atmosphere + + align:start position:0% +as humans is is there in the atmosphere + + + align:start position:0% +as humans is is there in the atmosphere +the plants the animals a lot of these + + align:start position:0% +the plants the animals a lot of these + + + align:start position:0% +the plants the animals a lot of these +things are creating a fluctuation to CO2 + + align:start position:0% +things are creating a fluctuation to CO2 + + + align:start position:0% +things are creating a fluctuation to CO2 +if you see even like over 1 million + + align:start position:0% +if you see even like over 1 million + + + align:start position:0% +if you see even like over 1 million +years ago there's still a fluctuation + + align:start position:0% +years ago there's still a fluctuation + + + align:start position:0% +years ago there's still a fluctuation +going up and down of the levels of CO2 + + align:start position:0% +going up and down of the levels of CO2 + + + align:start position:0% +going up and down of the levels of CO2 +in the atmosphere and you can actually + + align:start position:0% +in the atmosphere and you can actually + + + align:start position:0% +in the atmosphere and you can actually +do that in a very clever way with + + align:start position:0% +do that in a very clever way with + + + align:start position:0% +do that in a very clever way with +checking even like layers of old uh ice + + align:start position:0% +checking even like layers of old uh ice + + + align:start position:0% +checking even like layers of old uh ice +in the in the North Pole and so forth + + align:start position:0% +in the in the North Pole and so forth + + + align:start position:0% +in the in the North Pole and so forth +you can actually see how how the level + + align:start position:0% +you can actually see how how the level + + + align:start position:0% +you can actually see how how the level +of the of CO2 was back even 1 million + + align:start position:0% +of the of CO2 was back even 1 million + + + align:start position:0% +of the of CO2 was back even 1 million +years ago so you can actually based on + + align:start position:0% +years ago so you can actually based on + + + align:start position:0% +years ago so you can actually based on +those some clever physics models you can + + align:start position:0% +those some clever physics models you can + + + align:start position:0% +those some clever physics models you can +actually see how the level of CO2 was + + align:start position:0% +actually see how the level of CO2 was + + + align:start position:0% +actually see how the level of CO2 was +fluctuating but after the first + + align:start position:0% +fluctuating but after the first + + + align:start position:0% +fluctuating but after the first +Industrial Revolution this is what is + + align:start position:0% +Industrial Revolution this is what is + + + align:start position:0% +Industrial Revolution this is what is +started to happen so this is what we are + + align:start position:0% +started to happen so this is what we are + + + align:start position:0% +started to happen so this is what we are +now and that is around double the amount + + align:start position:0% +now and that is around double the amount + + + align:start position:0% +now and that is around double the amount +of CO2 in the atmosphere that has been + + align:start position:0% +of CO2 in the atmosphere that has been + + + align:start position:0% +of CO2 in the atmosphere that has been +for the last 1 million years so this is + + align:start position:0% +for the last 1 million years so this is + + + align:start position:0% +for the last 1 million years so this is +what what we are thinking about this + + align:start position:0% +what what we are thinking about this + + + align:start position:0% +what what we are thinking about this +might be a problem and the problem ends + + align:start position:0% +might be a problem and the problem ends + + + align:start position:0% +might be a problem and the problem ends +up being uh related to the amount of the + + align:start position:0% +up being uh related to the amount of the + + + align:start position:0% +up being uh related to the amount of the +the temperature levels into in the + + align:start position:0% +the temperature levels into in the + + + align:start position:0% +the temperature levels into in the +planet so this is what the again + + align:start position:0% +planet so this is what the again + + + align:start position:0% +planet so this is what the again +relative to 1980 this is how for the + + align:start position:0% +relative to 1980 this is how for the + + + align:start position:0% +relative to 1980 this is how for the +last decades and centuries it's been + + align:start position:0% +last decades and centuries it's been + + + align:start position:0% +last decades and centuries it's been +like the temperature + + align:start position:0% +like the temperature + + + align:start position:0% +like the temperature +in in the atmosphere and this is how it + + align:start position:0% +in in the atmosphere and this is how it + + + align:start position:0% +in in the atmosphere and this is how it +changed over the last year since we + + align:start position:0% +changed over the last year since we + + + align:start position:0% +changed over the last year since we +start burning fossil fuels to produce + + align:start position:0% +start burning fossil fuels to produce + + + align:start position:0% +start burning fossil fuels to produce +Goods to move to move and to do to heat + + align:start position:0% +Goods to move to move and to do to heat + + + align:start position:0% +Goods to move to move and to do to heat +our buildings and to do all sort of + + align:start position:0% +our buildings and to do all sort of + + + align:start position:0% +our buildings and to do all sort of +things so you see how the levels used to + + align:start position:0% +things so you see how the levels used to + + + align:start position:0% +things so you see how the levels used to +be something like here around + + align:start position:0% +be something like here around + + + align:start position:0% +be something like here around +fluctuating around zero and around the + + align:start position:0% +fluctuating around zero and around the + + + align:start position:0% +fluctuating around zero and around the +mid last century this starts to go all + + align:start position:0% +mid last century this starts to go all + + + align:start position:0% +mid last century this starts to go all +the way up to one one degree higher uh + + align:start position:0% +the way up to one one degree higher uh + + + align:start position:0% +the way up to one one degree higher uh +abnormally higher than that it used to + + align:start position:0% +abnormally higher than that it used to + + + align:start position:0% +abnormally higher than that it used to +be um this these are the Blue Line uh + + align:start position:0% +be um this these are the Blue Line uh + + + align:start position:0% +be um this these are the Blue Line uh +and how do we know or how do we think + + align:start position:0% +and how do we know or how do we think + + + align:start position:0% +and how do we know or how do we think +about the the role of humans in all of + + align:start position:0% +about the the role of humans in all of + + + align:start position:0% +about the the role of humans in all of +this is that if you model with some + + align:start position:0% +this is that if you model with some + + + align:start position:0% +this is that if you model with some +clever physics models where the + + align:start position:0% +clever physics models where the + + + align:start position:0% +clever physics models where the +temperatures will be using only physic + + align:start position:0% +temperatures will be using only physic + + + align:start position:0% +temperatures will be using only physic +physical parameters so different things + + align:start position:0% +physical parameters so different things + + + align:start position:0% +physical parameters so different things +of development of uh the uh the foresty + + align:start position:0% +of development of uh the uh the foresty + + + align:start position:0% +of development of uh the uh the foresty +development of animals and so forth uh + + align:start position:0% +development of animals and so forth uh + + + align:start position:0% +development of animals and so forth uh +using the blue modeling using 1,000 one + + align:start position:0% +using the blue modeling using 1,000 one + + + align:start position:0% +using the blue modeling using 1,000 one +million sorry multiple millions of + + align:start position:0% +million sorry multiple millions of + + + align:start position:0% +million sorry multiple millions of +simulations this is all where it should + + align:start position:0% +simulations this is all where it should + + + align:start position:0% +simulations this is all where it should +be without the the the influence of + + align:start position:0% +be without the the the influence of + + + align:start position:0% +be without the the the influence of +humankind so you can actually predict + + align:start position:0% +humankind so you can actually predict + + + align:start position:0% +humankind so you can actually predict +and forecast how the evolution of + + align:start position:0% +and forecast how the evolution of + + + align:start position:0% +and forecast how the evolution of +temperature will be and there any + + align:start position:0% +temperature will be and there any + + + align:start position:0% +temperature will be and there any +potential scenario that you can actually + + align:start position:0% +potential scenario that you can actually + + + align:start position:0% +potential scenario that you can actually +think of without human cane and you see + + align:start position:0% +think of without human cane and you see + + + align:start position:0% +think of without human cane and you see +that that is why way off of what the + + align:start position:0% +that that is why way off of what the + + + align:start position:0% +that that is why way off of what the +black line that is what we are observing + + align:start position:0% +black line that is what we are observing + + + align:start position:0% +black line that is what we are observing +the only way that you can really fit in + + align:start position:0% +the only way that you can really fit in + + + align:start position:0% +the only way that you can really fit in +that black line into simulations is if + + align:start position:0% +that black line into simulations is if + + + align:start position:0% +that black line into simulations is if +you introduce the idea that there are + + align:start position:0% +you introduce the idea that there are + + + align:start position:0% +you introduce the idea that there are +normally high levels of CO2 produce by + + align:start position:0% +normally high levels of CO2 produce by + + + align:start position:0% +normally high levels of CO2 produce by +man humankind so that's really the how + + align:start position:0% +man humankind so that's really the how + + + align:start position:0% +man humankind so that's really the how +the climate scientist and how all of the + + align:start position:0% +the climate scientist and how all of the + + + align:start position:0% +the climate scientist and how all of the +policy makers are thinking about the + + align:start position:0% +policy makers are thinking about the + + + align:start position:0% +policy makers are thinking about the +role of humans in all of this is that if + + align:start position:0% +role of humans in all of this is that if + + + align:start position:0% +role of humans in all of this is that if +you use any clever physics models here + + align:start position:0% +you use any clever physics models here + + + align:start position:0% +you use any clever physics models here +to predict the evolution of temperatures + + align:start position:0% +to predict the evolution of temperatures + + + align:start position:0% +to predict the evolution of temperatures +you can never fit what we are observing + + align:start position:0% +you can never fit what we are observing + + + align:start position:0% +you can never fit what we are observing +now in the in the atmosphere in terms of + + align:start position:0% +now in the in the atmosphere in terms of + + + align:start position:0% +now in the in the atmosphere in terms of +temperature the only way that you can + + align:start position:0% +temperature the only way that you can + + + align:start position:0% +temperature the only way that you can +fit this line if is you actually + + align:start position:0% +fit this line if is you actually + + + align:start position:0% +fit this line if is you actually +incorporate the man-made production of + + align:start position:0% +incorporate the man-made production of + + + align:start position:0% +incorporate the man-made production of +CO2 emissions in the atmosphere and + + align:start position:0% +CO2 emissions in the atmosphere and + + + align:start position:0% +CO2 emissions in the atmosphere and +that's why the scientists are saying + + align:start position:0% +that's why the scientists are saying + + + align:start position:0% +that's why the scientists are saying +that climate is changing and it's + + align:start position:0% +that climate is changing and it's + + + align:start position:0% +that climate is changing and it's +changing because of of man-made + + align:start position:0% +changing because of of man-made + + + align:start position:0% +changing because of of man-made +emissions and the the forecasting is not + + align:start position:0% +emissions and the the forecasting is not + + + align:start position:0% +emissions and the the forecasting is not +really uh helpful for us because if we + + align:start position:0% +really uh helpful for us because if we + + + align:start position:0% +really uh helpful for us because if we +keep producing CO2 in the amounts that + + align:start position:0% +keep producing CO2 in the amounts that + + + align:start position:0% +keep producing CO2 in the amounts that +we are producing no matter what the the + + align:start position:0% +we are producing no matter what the the + + + align:start position:0% +we are producing no matter what the the +scenario every line here is on a + + align:start position:0% +scenario every line here is on a + + + align:start position:0% +scenario every line here is on a +scenario you have millions of lines here + + align:start position:0% +scenario you have millions of lines here + + + align:start position:0% +scenario you have millions of lines here +no matter what the scenario you pick the + + align:start position:0% +no matter what the scenario you pick the + + + align:start position:0% +no matter what the scenario you pick the +the temperatures are going to keep going + + align:start position:0% +the temperatures are going to keep going + + + align:start position:0% +the temperatures are going to keep going +up and it's going to have a lot of bad + + align:start position:0% +up and it's going to have a lot of bad + + + align:start position:0% +up and it's going to have a lot of bad +stuff that we will + + align:start position:0% +stuff that we will + + + align:start position:0% +stuff that we will +see now in a + + align:start position:0% +see now in a + + + align:start position:0% +see now in a +bit uh this is one of the things that + + align:start position:0% +bit uh this is one of the things that + + + align:start position:0% +bit uh this is one of the things that +happens is not only that temperature + + align:start position:0% +happens is not only that temperature + + + align:start position:0% +happens is not only that temperature +this one degree uh here or two degrees + + align:start position:0% +this one degree uh here or two degrees + + + align:start position:0% +this one degree uh here or two degrees +is going to be just kind of like the + + align:start position:0% +is going to be just kind of like the + + + align:start position:0% +is going to be just kind of like the +average day is going to be one or two + + align:start position:0% +average day is going to be one or two + + + align:start position:0% +average day is going to be one or two +degrees hotter but it's also that the + + align:start position:0% +degrees hotter but it's also that the + + + align:start position:0% +degrees hotter but it's also that the +number especially here the number of + + align:start position:0% +number especially here the number of + + + align:start position:0% +number especially here the number of +days that are extremely hot are going to + + align:start position:0% +days that are extremely hot are going to + + + align:start position:0% +days that are extremely hot are going to +increase by a lot so this is not a a + + align:start position:0% +increase by a lot so this is not a a + + + align:start position:0% +increase by a lot so this is not a a +pleasant increase in the temperature + + align:start position:0% +pleasant increase in the temperature + + + align:start position:0% +pleasant increase in the temperature +especially in a place like Boston we can + + align:start position:0% +especially in a place like Boston we can + + + align:start position:0% +especially in a place like Boston we can +always appreciate this one or two uh + + align:start position:0% +always appreciate this one or two uh + + + align:start position:0% +always appreciate this one or two uh +degrees extra in the winter is this the + + align:start position:0% +degrees extra in the winter is this the + + + align:start position:0% +degrees extra in the winter is this the +number of heat WS the number of days + + align:start position:0% +number of heat WS the number of days + + + align:start position:0% +number of heat WS the number of days +that are extremely hot is going to + + align:start position:0% +that are extremely hot is going to + + + align:start position:0% +that are extremely hot is going to +increase by a lot and that is going to + + align:start position:0% +increase by a lot and that is going to + + + align:start position:0% +increase by a lot and that is going to +generate all of the problems that we + + align:start position:0% +generate all of the problems that we + + + align:start position:0% +generate all of the problems that we +also discuss in the healthy building + + align:start position:0% +also discuss in the healthy building + + + align:start position:0% +also discuss in the healthy building +lecture in terms of health and + + align:start position:0% +lecture in terms of health and + + + align:start position:0% +lecture in terms of health and +cardiovascular problems and so forth so + + align:start position:0% +cardiovascular problems and so forth so + + + align:start position:0% +cardiovascular problems and so forth so +this is this is the issue in terms of + + align:start position:0% +this is this is the issue in terms of + + + align:start position:0% +this is this is the issue in terms of +temperatures that the amount of days + + align:start position:0% +temperatures that the amount of days + + + align:start position:0% +temperatures that the amount of days +that are unbearably warm is going to + + align:start position:0% +that are unbearably warm is going to + + + align:start position:0% +that are unbearably warm is going to +increase disproportionally compared to + + align:start position:0% +increase disproportionally compared to + + + align:start position:0% +increase disproportionally compared to +the to the Past + + align:start position:0% +the to the Past + + + align:start position:0% +the to the Past +decades um and now beyond all of that we + + align:start position:0% +decades um and now beyond all of that we + + + align:start position:0% +decades um and now beyond all of that we +are going to cover now all of the + + align:start position:0% +are going to cover now all of the + + + align:start position:0% +are going to cover now all of the +disasters that are associated with with + + align:start position:0% +disasters that are associated with with + + + align:start position:0% +disasters that are associated with with +that but I want to make a distinction + + align:start position:0% +that but I want to make a distinction + + + align:start position:0% +that but I want to make a distinction +here when we are thinking about weather + + align:start position:0% +here when we are thinking about weather + + + align:start position:0% +here when we are thinking about weather +and when we are going to think about + + align:start position:0% +and when we are going to think about + + + align:start position:0% +and when we are going to think about +climate to each of these uh lines here + + align:start position:0% +climate to each of these uh lines here + + + align:start position:0% +climate to each of these uh lines here +if they're ultimately color is one day + + align:start position:0% +if they're ultimately color is one day + + + align:start position:0% +if they're ultimately color is one day +so it's one day here will be like this + + align:start position:0% +so it's one day here will be like this + + + align:start position:0% +so it's one day here will be like this +amount of this temperature like 30 + + align:start position:0% +amount of this temperature like 30 + + + align:start position:0% +amount of this temperature like 30 +degrees or whatever it will be in the in + + align:start position:0% +degrees or whatever it will be in the in + + + align:start position:0% +degrees or whatever it will be in the in +exit the distribution here will tell you + + align:start position:0% +exit the distribution here will tell you + + + align:start position:0% +exit the distribution here will tell you +the climate so climate describes + + align:start position:0% +the climate so climate describes + + + align:start position:0% +the climate so climate describes +long-term pattern of weather so every + + align:start position:0% +long-term pattern of weather so every + + + align:start position:0% +long-term pattern of weather so every +day you have a certain weather the + + align:start position:0% +day you have a certain weather the + + + align:start position:0% +day you have a certain weather the +weather is cold the weather is warm + + align:start position:0% +weather is cold the weather is warm + + + align:start position:0% +weather is cold the weather is warm +climate is this long-term distribution + + align:start position:0% +climate is this long-term distribution + + + align:start position:0% +climate is this long-term distribution +of weather and that's what it's changing + + align:start position:0% +of weather and that's what it's changing + + + align:start position:0% +of weather and that's what it's changing +and that's what people are responding to + + align:start position:0% +and that's what people are responding to + + + align:start position:0% +and that's what people are responding to +because it is stupid to believe that + + align:start position:0% +because it is stupid to believe that + + + align:start position:0% +because it is stupid to believe that +people will make an investment in a + + align:start position:0% +people will make an investment in a + + + align:start position:0% +people will make an investment in a +building that are planning to hold for + + align:start position:0% +building that are planning to hold for + + + align:start position:0% +building that are planning to hold for +20 30 40 years based on today's weather + + align:start position:0% +20 30 40 years based on today's weather + + + align:start position:0% +20 30 40 years based on today's weather +they are going to be thinking about it + + align:start position:0% +they are going to be thinking about it + + + align:start position:0% +they are going to be thinking about it +in terms of what they expect the weather + + align:start position:0% +in terms of what they expect the weather + + + align:start position:0% +in terms of what they expect the weather +all the weather the daily weather to be + + align:start position:0% +all the weather the daily weather to be + + + align:start position:0% +all the weather the daily weather to be +over the period of 30 40 50 years that + + align:start position:0% +over the period of 30 40 50 years that + + + align:start position:0% +over the period of 30 40 50 years that +this asset is going to be in our hands + + align:start position:0% +this asset is going to be in our hands + + + align:start position:0% +this asset is going to be in our hands +so what we are interested here is about + + align:start position:0% +so what we are interested here is about + + + align:start position:0% +so what we are interested here is about +this long-term distribution this + + align:start position:0% +this long-term distribution this + + + align:start position:0% +this long-term distribution this +long-term climate these 30-year averages + + align:start position:0% +long-term climate these 30-year averages + + + align:start position:0% +long-term climate these 30-year averages +of temperature 30 year averages of + + align:start position:0% +of temperature 30 year averages of + + + align:start position:0% +of temperature 30 year averages of +rainfall 30-year averages of uh Cyclones + + align:start position:0% +rainfall 30-year averages of uh Cyclones + + + align:start position:0% +rainfall 30-year averages of uh Cyclones +hurricanes and so forth this is what we + + align:start position:0% +hurricanes and so forth this is what we + + + align:start position:0% +hurricanes and so forth this is what we +are going to discuss here today and this + + align:start position:0% +are going to discuss here today and this + + + align:start position:0% +are going to discuss here today and this +what we are going to discuss here over + + align:start position:0% +what we are going to discuss here over + + + align:start position:0% +what we are going to discuss here over +the next two three weeks we are not + + align:start position:0% +the next two three weeks we are not + + + align:start position:0% +the next two three weeks we are not +going to discuss how people are impacted + + align:start position:0% +going to discuss how people are impacted + + + align:start position:0% +going to discuss how people are impacted +or the decisions of people are impacted + + align:start position:0% +or the decisions of people are impacted + + + align:start position:0% +or the decisions of people are impacted +by this one day cold day one day that is + + align:start position:0% +by this one day cold day one day that is + + + align:start position:0% +by this one day cold day one day that is +warm one day that is rainy no we are + + align:start position:0% +warm one day that is rainy no we are + + + align:start position:0% +warm one day that is rainy no we are +thinking about over the last 10 decades + + align:start position:0% +thinking about over the last 10 decades + + + align:start position:0% +thinking about over the last 10 decades +the the average temperature has been uh + + align:start position:0% +the the average temperature has been uh + + + align:start position:0% +the the average temperature has been uh +20° C 80 degrees Fahrenheit and now + + align:start position:0% +20° C 80 degrees Fahrenheit and now + + + align:start position:0% +20° C 80 degrees Fahrenheit and now +actually our average temperature goes to + + align:start position:0% +actually our average temperature goes to + + + align:start position:0% +actually our average temperature goes to +90 degrees Fahrenheit and our average + + align:start position:0% +90 degrees Fahrenheit and our average + + + align:start position:0% +90 degrees Fahrenheit and our average +temperature goes to 30 deges celi that's + + align:start position:0% +temperature goes to 30 deges celi that's + + + align:start position:0% +temperature goes to 30 deges celi that's +what we are thinking we are thinking + + align:start position:0% +what we are thinking we are thinking + + + align:start position:0% +what we are thinking we are thinking +about we are here in terms of + + align:start position:0% +about we are here in terms of + + + align:start position:0% +about we are here in terms of +temperatures and we go here in terms of + + align:start position:0% +temperatures and we go here in terms of + + + align:start position:0% +temperatures and we go here in terms of +temperatures and this is here to stay + + align:start position:0% +temperatures and this is here to stay + + + align:start position:0% +temperatures and this is here to stay +and this is nothing that is going to be + + align:start position:0% +and this is nothing that is going to be + + + align:start position:0% +and this is nothing that is going to be +a fluctuation from one day to the other + + align:start position:0% +a fluctuation from one day to the other + + + align:start position:0% +a fluctuation from one day to the other +because these long-term trends is going + + align:start position:0% +because these long-term trends is going + + + align:start position:0% +because these long-term trends is going +to change is going to shape the + + align:start position:0% +to change is going to shape the + + + align:start position:0% +to change is going to shape the +expectations or the forecast of a lot of + + align:start position:0% +expectations or the forecast of a lot of + + + align:start position:0% +expectations or the forecast of a lot of +our analysts that are going to consider + + align:start position:0% +our analysts that are going to consider + + + align:start position:0% +our analysts that are going to consider +what to make in terms of building an + + align:start position:0% +what to make in terms of building an + + + align:start position:0% +what to make in terms of building an +asset transforming an asset and so forth + + align:start position:0% +asset transforming an asset and so forth + + + align:start position:0% +asset transforming an asset and so forth +this is what really matters because this + + align:start position:0% +this is what really matters because this + + + align:start position:0% +this is what really matters because this +is going + + align:start position:0% +is going + + + align:start position:0% +is going +to shape all of our valuations in terms + + align:start position:0% +to shape all of our valuations in terms + + + align:start position:0% +to shape all of our valuations in terms +of uh considering what to do with an + + align:start position:0% +of uh considering what to do with an + + + align:start position:0% +of uh considering what to do with an +asset what to do with a portfolio what + + align:start position:0% +asset what to do with a portfolio what + + + align:start position:0% +asset what to do with a portfolio what +what we what matter for us is always the + + align:start position:0% +what we what matter for us is always the + + + align:start position:0% +what we what matter for us is always the +long-term expectations the long-term uh + + align:start position:0% +long-term expectations the long-term uh + + + align:start position:0% +long-term expectations the long-term uh +beliefs that we have there and this is + + align:start position:0% +beliefs that we have there and this is + + + align:start position:0% +beliefs that we have there and this is +what climate change is about is that + + align:start position:0% +what climate change is about is that + + + align:start position:0% +what climate change is about is that +those expectations in terms of how the + + align:start position:0% +those expectations in terms of how the + + + align:start position:0% +those expectations in terms of how the +amenities of a place how the asset the + + align:start position:0% +amenities of a place how the asset the + + + align:start position:0% +amenities of a place how the asset the +cost of an assets are going to be are + + align:start position:0% +cost of an assets are going to be are + + + align:start position:0% +cost of an assets are going to be are +going to change just because the climate + + align:start position:0% +going to change just because the climate + + + align:start position:0% +going to change just because the climate +that this asset is exposed to is + + align:start position:0% +that this asset is exposed to is + + + align:start position:0% +that this asset is exposed to is +changing all right they are not going to + + align:start position:0% +changing all right they are not going to + + + align:start position:0% +changing all right they are not going to +be shape by what happens today in Boston + + align:start position:0% +be shape by what happens today in Boston + + + align:start position:0% +be shape by what happens today in Boston +is going to be safe but with what we + + align:start position:0% +is going to be safe but with what we + + + align:start position:0% +is going to be safe but with what we +think that in the next 10 15 20 years is + + align:start position:0% +think that in the next 10 15 20 years is + + + align:start position:0% +think that in the next 10 15 20 years is +happening in Boston or in New York or + + align:start position:0% +happening in Boston or in New York or + + + align:start position:0% +happening in Boston or in New York or +whatever we are considering that Carlos + + align:start position:0% +whatever we are considering that Carlos + + + align:start position:0% +whatever we are considering that Carlos +good I I saw you a bit + + align:start position:0% +good I I saw you a bit + + + align:start position:0% +good I I saw you a bit +confused and and this is what is + + align:start position:0% +confused and and this is what is + + + align:start position:0% +confused and and this is what is +changing and this is what you see if you + + align:start position:0% +changing and this is what you see if you + + + align:start position:0% +changing and this is what you see if you +see the uh the UN ipcc reports they are + + align:start position:0% +see the uh the UN ipcc reports they are + + + align:start position:0% +see the uh the UN ipcc reports they are +the ones that are actually investigating + + align:start position:0% +the ones that are actually investigating + + + align:start position:0% +the ones that are actually investigating +how the climate is changing and the + + align:start position:0% +how the climate is changing and the + + + align:start position:0% +how the climate is changing and the +attribution of of that change to to + + align:start position:0% +attribution of of that change to to + + + align:start position:0% +attribution of of that change to to +humankind that's you is what you see + + align:start position:0% +humankind that's you is what you see + + + align:start position:0% +humankind that's you is what you see +that there is a change in beliefs and + + align:start position:0% +that there is a change in beliefs and + + + align:start position:0% +that there is a change in beliefs and +change in expectations of how the + + align:start position:0% +change in expectations of how the + + + align:start position:0% +change in expectations of how the +climate is going to be so you see that + + align:start position:0% +climate is going to be so you see that + + + align:start position:0% +climate is going to be so you see that +they started with saying that there is a + + align:start position:0% +they started with saying that there is a + + + align:start position:0% +they started with saying that there is a +a a relationship between greenhouse + + align:start position:0% +a a relationship between greenhouse + + + align:start position:0% +a a relationship between greenhouse +evisions and uh there's a change an + + align:start position:0% +evisions and uh there's a change an + + + align:start position:0% +evisions and uh there's a change an +abnormal uh abnormal levels of + + align:start position:0% +abnormal uh abnormal levels of + + + align:start position:0% +abnormal uh abnormal levels of +greenhouse emissions uh and then that + + align:start position:0% +greenhouse emissions uh and then that + + + align:start position:0% +greenhouse emissions uh and then that +started to connect it to to climate they + + align:start position:0% +started to connect it to to climate they + + + align:start position:0% +started to connect it to to climate they +started to use Wars that are stronger + + align:start position:0% +started to use Wars that are stronger + + + align:start position:0% +started to use Wars that are stronger +and stronger in terms of the probability + + align:start position:0% +and stronger in terms of the probability + + + align:start position:0% +and stronger in terms of the probability +of a climate change to be occurring so + + align:start position:0% +of a climate change to be occurring so + + + align:start position:0% +of a climate change to be occurring so +you see from 1995 they go from suggest + + align:start position:0% +you see from 1995 they go from suggest + + + align:start position:0% +you see from 1995 they go from suggest +20 20 2001 they go to likely very likely + + align:start position:0% +20 20 2001 they go to likely very likely + + + align:start position:0% +20 20 2001 they go to likely very likely +extremely likely all the way down to is + + align:start position:0% +extremely likely all the way down to is + + + align:start position:0% +extremely likely all the way down to is +already impacting us + + align:start position:0% +already impacting us + + + align:start position:0% +already impacting us +so this is something that when you are + + align:start position:0% +so this is something that when you are + + + align:start position:0% +so this is something that when you are +making decisions you see how the + + align:start position:0% +making decisions you see how the + + + align:start position:0% +making decisions you see how the +approach and the belief is changing over + + align:start position:0% +approach and the belief is changing over + + + align:start position:0% +approach and the belief is changing over +time and + + align:start position:0% +time and + + + align:start position:0% +time and +therefore that should have consequences + + align:start position:0% +therefore that should have consequences + + + align:start position:0% +therefore that should have consequences +into the decisions that people are + + align:start position:0% +into the decisions that people are + + + align:start position:0% +into the decisions that people are +making in terms of long-term uh + + align:start position:0% +making in terms of long-term uh + + + align:start position:0% +making in terms of long-term uh +allocations of capital long-terms decis + + align:start position:0% +allocations of capital long-terms decis + + + align:start position:0% +allocations of capital long-terms decis +investment decisions and especially when + + align:start position:0% +investment decisions and especially when + + + align:start position:0% +investment decisions and especially when +it comes to 50 years when it comes to + + align:start position:0% +it comes to 50 years when it comes to + + + align:start position:0% +it comes to 50 years when it comes to +things that are kind of two three uh + + align:start position:0% +things that are kind of two three uh + + + align:start position:0% +things that are kind of two three uh +decades ahead this is something that it + + align:start position:0% +decades ahead this is something that it + + + align:start position:0% +decades ahead this is something that it +is not anymore something that our next + + align:start position:0% +is not anymore something that our next + + + align:start position:0% +is not anymore something that our next +gener generation will be impacted but + + align:start position:0% +gener generation will be impacted but + + + align:start position:0% +gener generation will be impacted but +it's actually that our generation is + + align:start position:0% +it's actually that our generation is + + + align:start position:0% +it's actually that our generation is +impacted and especially when you think + + align:start position:0% +impacted and especially when you think + + + align:start position:0% +impacted and especially when you think +about insurance companies Pension funds + + align:start position:0% +about insurance companies Pension funds + + + align:start position:0% +about insurance companies Pension funds +and so forth those are already within + + align:start position:0% +and so forth those are already within + + + align:start position:0% +and so forth those are already within +the investment Horizon of those folks + + align:start position:0% +the investment Horizon of those folks + + + align:start position:0% +the investment Horizon of those folks +and when you're thinking about buying an + + align:start position:0% +and when you're thinking about buying an + + + align:start position:0% +and when you're thinking about buying an +asset to hold it uh for using purposes + + align:start position:0% +asset to hold it uh for using purposes + + + align:start position:0% +asset to hold it uh for using purposes +and so forth 20 30 years is something + + align:start position:0% +and so forth 20 30 years is something + + + align:start position:0% +and so forth 20 30 years is something +that it is not anymore the next guy that + + align:start position:0% +that it is not anymore the next guy that + + + align:start position:0% +that it is not anymore the next guy that +buys the building but is actually + + align:start position:0% +buys the building but is actually + + + align:start position:0% +buys the building but is actually +something that it is me the one that is + + align:start position:0% +something that it is me the one that is + + + align:start position:0% +something that it is me the one that is +going to suffer uh the expected damages + + align:start position:0% +going to suffer uh the expected damages + + + align:start position:0% +going to suffer uh the expected damages +of a hurricane or the expected cost + + align:start position:0% +of a hurricane or the expected cost + + + align:start position:0% +of a hurricane or the expected cost +associated with having an an AC running + + align:start position:0% +associated with having an an AC running + + + align:start position:0% +associated with having an an AC running +full power not 20 days a year but + + align:start position:0% +full power not 20 days a year but + + + align:start position:0% +full power not 20 days a year but +actually 40 days a year so this is + + align:start position:0% +actually 40 days a year so this is + + + align:start position:0% +actually 40 days a year so this is +exactly this is the key of climate + + align:start position:0% +exactly this is the key of climate + + + align:start position:0% +exactly this is the key of climate +change this is actually what we have to + + align:start position:0% +change this is actually what we have to + + + align:start position:0% +change this is actually what we have to +think about how that changes as is going + + align:start position:0% +think about how that changes as is going + + + align:start position:0% +think about how that changes as is going +to influence the real estate market is + + align:start position:0% +to influence the real estate market is + + + align:start position:0% +to influence the real estate market is +going to influence the real estate + + align:start position:0% +going to influence the real estate + + + align:start position:0% +going to influence the real estate +investment decisions it is going from ah + + align:start position:0% +investment decisions it is going from ah + + + align:start position:0% +investment decisions it is going from ah +it seems nothing changes to oh it seems + + align:start position:0% +it seems nothing changes to oh it seems + + + align:start position:0% +it seems nothing changes to oh it seems +that there is a change here in in the + + align:start position:0% +that there is a change here in in the + + + align:start position:0% +that there is a change here in in the +atmosphere and actually it seems that + + align:start position:0% +atmosphere and actually it seems that + + + align:start position:0% +atmosphere and actually it seems that +it's actually something that is related + + align:start position:0% +it's actually something that is related + + + align:start position:0% +it's actually something that is related +to how we produce uh goods and how heat + + align:start position:0% +to how we produce uh goods and how heat + + + align:start position:0% +to how we produce uh goods and how heat +buildings the CO2 emissions that we + + align:start position:0% +buildings the CO2 emissions that we + + + align:start position:0% +buildings the CO2 emissions that we +produce that is also something that we + + align:start position:0% +produce that is also something that we + + + align:start position:0% +produce that is also something that we +know is not going to change in the next + + align:start position:0% +know is not going to change in the next + + + align:start position:0% +know is not going to change in the next +a few years and this actually something + + align:start position:0% +a few years and this actually something + + + align:start position:0% +a few years and this actually something +that hey it seems that we have enough + + align:start position:0% +that hey it seems that we have enough + + + align:start position:0% +that hey it seems that we have enough +evidence to see that the EM the the + + align:start position:0% +evidence to see that the EM the the + + + align:start position:0% +evidence to see that the EM the the +climate already changed when you compare + + align:start position:0% +climate already changed when you compare + + + align:start position:0% +climate already changed when you compare +it to the last 20 30 years uh beforehand + + align:start position:0% +it to the last 20 30 years uh beforehand + + + align:start position:0% +it to the last 20 30 years uh beforehand +okay how is it changing and where is it + + align:start position:0% +okay how is it changing and where is it + + + align:start position:0% +okay how is it changing and where is it +changing if you see uh so on the one + + align:start position:0% +changing if you see uh so on the one + + + align:start position:0% +changing if you see uh so on the one +hand as I said as we saw the weather is + + align:start position:0% +hand as I said as we saw the weather is + + + align:start position:0% +hand as I said as we saw the weather is +uh the climate is getting hot hotter and + + align:start position:0% +uh the climate is getting hot hotter and + + + align:start position:0% +uh the climate is getting hot hotter and +hotter the amount of heat waves are are + + align:start position:0% +hotter the amount of heat waves are are + + + align:start position:0% +hotter the amount of heat waves are are +increasing everywhere in the world so if + + align:start position:0% +increasing everywhere in the world so if + + + align:start position:0% +increasing everywhere in the world so if +you compare the differences with 1980s + + align:start position:0% +you compare the differences with 1980s + + + align:start position:0% +you compare the differences with 1980s +in temperature you see that everywhere + + align:start position:0% +in temperature you see that everywhere + + + align:start position:0% +in temperature you see that everywhere +in the world is getting hotter and that + + align:start position:0% +in the world is getting hotter and that + + + align:start position:0% +in the world is getting hotter and that +means that you know people are exposed + + align:start position:0% +means that you know people are exposed + + + align:start position:0% +means that you know people are exposed +to uncomfortably warm weather when it + + align:start position:0% +to uncomfortably warm weather when it + + + align:start position:0% +to uncomfortably warm weather when it +comes to selecting where to live much + + align:start position:0% +comes to selecting where to live much + + + align:start position:0% +comes to selecting where to live much +more than than they used to be + + align:start position:0% +more than than they used to be + + + align:start position:0% +more than than they used to be +especially in areas that were already + + align:start position:0% +especially in areas that were already + + + align:start position:0% +especially in areas that were already +warm um you have more problems with + + align:start position:0% +warm um you have more problems with + + + align:start position:0% +warm um you have more problems with +health more problems with different heat + + align:start position:0% +health more problems with different heat + + + align:start position:0% +health more problems with different heat +related disease with cardiovascular + + align:start position:0% +related disease with cardiovascular + + + align:start position:0% +related disease with cardiovascular +problems and so forth and then you also + + align:start position:0% +problems and so forth and then you also + + + align:start position:0% +problems and so forth and then you also +have a change in the in the distribution + + align:start position:0% +have a change in the in the distribution + + + align:start position:0% +have a change in the in the distribution +of precipitation so as the the + + align:start position:0% +of precipitation so as the the + + + align:start position:0% +of precipitation so as the the +atmosphere gets warmer it has a + + align:start position:0% +atmosphere gets warmer it has a + + + align:start position:0% +atmosphere gets warmer it has a +different capacity to absorb uh moisture + + align:start position:0% +different capacity to absorb uh moisture + + + align:start position:0% +different capacity to absorb uh moisture +and actually distribute that moisture so + + align:start position:0% +and actually distribute that moisture so + + + align:start position:0% +and actually distribute that moisture so +you see that on the one hand you get + + align:start position:0% +you see that on the one hand you get + + + align:start position:0% +you see that on the one hand you get +more uh problems with draws and people + + align:start position:0% +more uh problems with draws and people + + + align:start position:0% +more uh problems with draws and people +that have droughts and people that are + + align:start position:0% +that have droughts and people that are + + + align:start position:0% +that have droughts and people that are +coming from the area of California and + + align:start position:0% +coming from the area of California and + + + align:start position:0% +coming from the area of California and +so for can I speak to the idea that it + + align:start position:0% +so for can I speak to the idea that it + + + align:start position:0% +so for can I speak to the idea that it +is much more severe than it used to be + + align:start position:0% +is much more severe than it used to be + + + align:start position:0% +is much more severe than it used to be +10 15 20 years ago and also people I + + align:start position:0% +10 15 20 years ago and also people I + + + align:start position:0% +10 15 20 years ago and also people I +come from Spain + + align:start position:0% +come from Spain + + + align:start position:0% +come from Spain +uh we have like what it used to be a bad + + align:start position:0% +uh we have like what it used to be a bad + + + align:start position:0% +uh we have like what it used to be a bad +year in terms of having the Lakes almost + + align:start position:0% +year in terms of having the Lakes almost + + + align:start position:0% +year in terms of having the Lakes almost +empty now is sort of like the normal + + align:start position:0% +empty now is sort of like the normal + + + align:start position:0% +empty now is sort of like the normal +routine to see that the lakes are really + + align:start position:0% +routine to see that the lakes are really + + + align:start position:0% +routine to see that the lakes are really +being really empty and having problems + + align:start position:0% +being really empty and having problems + + + align:start position:0% +being really empty and having problems +for the Agriculture and having problems + + align:start position:0% +for the Agriculture and having problems + + + align:start position:0% +for the Agriculture and having problems +for H giving water to certain cities um + + align:start position:0% +for H giving water to certain cities um + + + align:start position:0% +for H giving water to certain cities um +and if you combine hot temperatures with + + align:start position:0% +and if you combine hot temperatures with + + + align:start position:0% +and if you combine hot temperatures with +dry temperatures you have the perfect + + align:start position:0% +dry temperatures you have the perfect + + + align:start position:0% +dry temperatures you have the perfect +scenario for wildfires so again if you + + align:start position:0% +scenario for wildfires so again if you + + + align:start position:0% +scenario for wildfires so again if you +say something from California you see + + align:start position:0% +say something from California you see + + + align:start position:0% +say something from California you see +that year after year you have in the + + align:start position:0% +that year after year you have in the + + + align:start position:0% +that year after year you have in the +news that there has been a a wildfire + + align:start position:0% +news that there has been a a wildfire + + + align:start position:0% +news that there has been a a wildfire +somewhere near a city and that has some + + align:start position:0% +somewhere near a city and that has some + + + align:start position:0% +somewhere near a city and that has some +infrastructure being destroyed some + + align:start position:0% +infrastructure being destroyed some + + + align:start position:0% +infrastructure being destroyed some +buildings being at the risk of fire and + + align:start position:0% +buildings being at the risk of fire and + + + align:start position:0% +buildings being at the risk of fire and +so forth so again something that used to + + align:start position:0% +so forth so again something that used to + + + align:start position:0% +so forth so again something that used to +happen once in a decade is now happening + + align:start position:0% +happen once in a decade is now happening + + + align:start position:0% +happen once in a decade is now happening +every year and that is again the + + align:start position:0% +every year and that is again the + + + align:start position:0% +every year and that is again the +probability change that we want to use + + align:start position:0% +probability change that we want to use + + + align:start position:0% +probability change that we want to use +in terms of how do people are responding + + align:start position:0% +in terms of how do people are responding + + + align:start position:0% +in terms of how do people are responding +in the real estate market and how that + + align:start position:0% +in the real estate market and how that + + + align:start position:0% +in the real estate market and how that +is affecting the value and the different + + align:start position:0% +is affecting the value and the different + + + align:start position:0% +is affecting the value and the different +decisions that are happening in the + + align:start position:0% +decisions that are happening in the + + + align:start position:0% +decisions that are happening in the +build + + align:start position:0% +build + + + align:start position:0% +build +environment and on the other hand you + + align:start position:0% +environment and on the other hand you + + + align:start position:0% +environment and on the other hand you +also have uh the of too much water in + + align:start position:0% +also have uh the of too much water in + + + align:start position:0% +also have uh the of too much water in +other places so if you see the the level + + align:start position:0% +other places so if you see the the level + + + align:start position:0% +other places so if you see the the level +of ice in in places like Antarctica in + + align:start position:0% +of ice in in places like Antarctica in + + + align:start position:0% +of ice in in places like Antarctica in +places like uh the North Pole or or + + align:start position:0% +places like uh the North Pole or or + + + align:start position:0% +places like uh the North Pole or or +Greenland you see that the amount of uh + + align:start position:0% +Greenland you see that the amount of uh + + + align:start position:0% +Greenland you see that the amount of uh +ice that is in there is much much lower + + align:start position:0% +ice that is in there is much much lower + + + align:start position:0% +ice that is in there is much much lower +than it used to be and it's not only the + + align:start position:0% +than it used to be and it's not only the + + + align:start position:0% +than it used to be and it's not only the +what the the ice that is generating from + + align:start position:0% +what the the ice that is generating from + + + align:start position:0% +what the the ice that is generating from +year to year but actually the ice that + + align:start position:0% +year to year but actually the ice that + + + align:start position:0% +year to year but actually the ice that +has been there for thousands of years is + + align:start position:0% +has been there for thousands of years is + + + align:start position:0% +has been there for thousands of years is +now being melted and it's going to take + + align:start position:0% +now being melted and it's going to take + + + align:start position:0% +now being melted and it's going to take +a lot of time if ever it's going to be + + align:start position:0% +a lot of time if ever it's going to be + + + align:start position:0% +a lot of time if ever it's going to be +recovered that is going to be more more + + align:start position:0% +recovered that is going to be more more + + + align:start position:0% +recovered that is going to be more more +water that is coming to the into the + + align:start position:0% +water that is coming to the into the + + + align:start position:0% +water that is coming to the into the +oceans and the season is going to make + + align:start position:0% +oceans and the season is going to make + + + align:start position:0% +oceans and the season is going to make +ultimately that the the coastal cities + + align:start position:0% +ultimately that the the coastal cities + + + align:start position:0% +ultimately that the the coastal cities +like Boston are going to have uh a sea + + align:start position:0% +like Boston are going to have uh a sea + + + align:start position:0% +like Boston are going to have uh a sea +level rise + + align:start position:0% +level rise + + + align:start position:0% +level rise +problem and not only that so even if you + + align:start position:0% +problem and not only that so even if you + + + align:start position:0% +problem and not only that so even if you +are not in the coastal areas what you + + align:start position:0% +are not in the coastal areas what you + + + align:start position:0% +are not in the coastal areas what you +see is that because of the distribution + + align:start position:0% +see is that because of the distribution + + + align:start position:0% +see is that because of the distribution +in moist or in the atmosphere you're not + + align:start position:0% +in moist or in the atmosphere you're not + + + align:start position:0% +in moist or in the atmosphere you're not +only having more problems with r but + + align:start position:0% +only having more problems with r but + + + align:start position:0% +only having more problems with r but +also you're having that when there is a + + align:start position:0% +also you're having that when there is a + + + align:start position:0% +also you're having that when there is a +rain is more likely to be a a big storm + + align:start position:0% +rain is more likely to be a a big storm + + + align:start position:0% +rain is more likely to be a a big storm +that you're going to discharge big + + align:start position:0% +that you're going to discharge big + + + align:start position:0% +that you're going to discharge big +amount of water in a given point often + + align:start position:0% +amount of water in a given point often + + + align:start position:0% +amount of water in a given point often +in a given region and it's going to make + + align:start position:0% +in a given region and it's going to make + + + align:start position:0% +in a given region and it's going to make +very difficult for that region to absorb + + align:start position:0% +very difficult for that region to absorb + + + align:start position:0% +very difficult for that region to absorb +the soil to absorb that that water is + + align:start position:0% +the soil to absorb that that water is + + + align:start position:0% +the soil to absorb that that water is +going to generate a lot of problems with + + align:start position:0% +going to generate a lot of problems with + + + align:start position:0% +going to generate a lot of problems with +with floods all over the place and + + align:start position:0% +with floods all over the place and + + + align:start position:0% +with floods all over the place and +especially next to to these big Rivers + + align:start position:0% +especially next to to these big Rivers + + + align:start position:0% +especially next to to these big Rivers +so there is no area that is not impacted + + align:start position:0% +so there is no area that is not impacted + + + align:start position:0% +so there is no area that is not impacted +by this risk in a lot of places like the + + align:start position:0% +by this risk in a lot of places like the + + + align:start position:0% +by this risk in a lot of places like the +United States not only the sea the the + + align:start position:0% +United States not only the sea the the + + + align:start position:0% +United States not only the sea the the +ones next to the sea but also all over + + align:start position:0% +ones next to the sea but also all over + + + align:start position:0% +ones next to the sea but also all over +all over the region you have the problem + + align:start position:0% +all over the region you have the problem + + + align:start position:0% +all over the region you have the problem +that you can have uh the chance to this + + align:start position:0% +that you can have uh the chance to this + + + align:start position:0% +that you can have uh the chance to this +biggest stor being being larger and + + align:start position:0% +biggest stor being being larger and + + + align:start position:0% +biggest stor being being larger and +therefore having big problems for water + + align:start position:0% +therefore having big problems for water + + + align:start position:0% +therefore having big problems for water +management and being able to cope with + + align:start position:0% +management and being able to cope with + + + align:start position:0% +management and being able to cope with +that amount of water in a very short + + align:start position:0% +that amount of water in a very short + + + align:start position:0% +that amount of water in a very short +term this will happens for example in + + align:start position:0% +term this will happens for example in + + + align:start position:0% +term this will happens for example in +Germany for those that are from Europe + + align:start position:0% +Germany for those that are from Europe + + + align:start position:0% +Germany for those that are from Europe +couple of years ago I was actually + + align:start position:0% +couple of years ago I was actually + + + align:start position:0% +couple of years ago I was actually +really nearby uh there out of the sudden + + align:start position:0% +really nearby uh there out of the sudden + + + align:start position:0% +really nearby uh there out of the sudden +there was a big storm and there was this + + align:start position:0% +there was a big storm and there was this + + + align:start position:0% +there was a big storm and there was this +one of the main rivers that got flooded + + align:start position:0% +one of the main rivers that got flooded + + + align:start position:0% +one of the main rivers that got flooded +and areas in Belgium in Germany and in + + align:start position:0% +and areas in Belgium in Germany and in + + + align:start position:0% +and areas in Belgium in Germany and in +in uh in the Netherlands got completely + + align:start position:0% +in uh in the Netherlands got completely + + + align:start position:0% +in uh in the Netherlands got completely +dilapidated by by the water and a lot of + + align:start position:0% +dilapidated by by the water and a lot of + + + align:start position:0% +dilapidated by by the water and a lot of +people died because especially in + + align:start position:0% +people died because especially in + + + align:start position:0% +people died because especially in +Germany people can't live in basements + + align:start position:0% +Germany people can't live in basements + + + align:start position:0% +Germany people can't live in basements +and they were worn too late they + + align:start position:0% +and they were worn too late they + + + align:start position:0% +and they were worn too late they +couldn't escape the basement and then + + align:start position:0% +couldn't escape the basement and then + + + align:start position:0% +couldn't escape the basement and then +the water came in into their their + + align:start position:0% +the water came in into their their + + + align:start position:0% +the water came in into their their +houses and then they died and at the + + align:start position:0% +houses and then they died and at the + + + align:start position:0% +houses and then they died and at the +same time Shi is originally from jeno at + + align:start position:0% +same time Shi is originally from jeno at + + + align:start position:0% +same time Shi is originally from jeno at +the very same time there was a big + + align:start position:0% +the very same time there was a big + + + align:start position:0% +the very same time there was a big +floating in in jeno for the exact same + + align:start position:0% +floating in in jeno for the exact same + + + align:start position:0% +floating in in jeno for the exact same +reason of big precipitation coming in + + align:start position:0% +reason of big precipitation coming in + + + align:start position:0% +reason of big precipitation coming in +and being unable to absorb all of that + + align:start position:0% +and being unable to absorb all of that + + + align:start position:0% +and being unable to absorb all of that +water + + align:start position:0% +water + + + align:start position:0% +water +so those events that again used to + + align:start position:0% +so those events that again used to + + + align:start position:0% +so those events that again used to +happen once in a lifetime now are + + align:start position:0% +happen once in a lifetime now are + + + align:start position:0% +happen once in a lifetime now are +happening more and more often and what + + align:start position:0% +happening more and more often and what + + + align:start position:0% +happening more and more often and what +it used to be something that you + + align:start position:0% +it used to be something that you + + + align:start position:0% +it used to be something that you +wouldn't care at all when you were + + align:start position:0% +wouldn't care at all when you were + + + align:start position:0% +wouldn't care at all when you were +underwriting any asset or making any + + align:start position:0% +underwriting any asset or making any + + + align:start position:0% +underwriting any asset or making any +decision now it comes to be very + + align:start position:0% +decision now it comes to be very + + + align:start position:0% +decision now it comes to be very +responsible if you you have no + + align:start position:0% +responsible if you you have no + + + align:start position:0% +responsible if you you have no +consideration for them because it's very + + align:start position:0% +consideration for them because it's very + + + align:start position:0% +consideration for them because it's very +very much more frequent than they used + + align:start position:0% +very much more frequent than they used + + + align:start position:0% +very much more frequent than they used +to be and this is again the probability + + align:start position:0% +to be and this is again the probability + + + align:start position:0% +to be and this is again the probability +that we want to think carefully about + + align:start position:0% +that we want to think carefully about + + + align:start position:0% +that we want to think carefully about +how that impact the the real estate + + align:start position:0% +how that impact the the real estate + + + align:start position:0% +how that impact the the real estate +markets and this is + + align:start position:0% +markets and this is + + + align:start position:0% +markets and this is +the overall trend this is the uh the + + align:start position:0% +the overall trend this is the uh the + + + align:start position:0% +the overall trend this is the uh the +number of uh every bar is the number of + + align:start position:0% +number of uh every bar is the number of + + + align:start position:0% +number of uh every bar is the number of +1 billion disasters across different + + align:start position:0% +1 billion disasters across different + + + align:start position:0% +1 billion disasters across different +type of uh events so draw droughts + + align:start position:0% +type of uh events so draw droughts + + + align:start position:0% +type of uh events so draw droughts +wildfires floting and so forth and if + + align:start position:0% +wildfires floting and so forth and if + + + align:start position:0% +wildfires floting and so forth and if +you see over the last decade there is a + + align:start position:0% +you see over the last decade there is a + + + align:start position:0% +you see over the last decade there is a +clear upward Trend into the number of + + align:start position:0% +clear upward Trend into the number of + + + align:start position:0% +clear upward Trend into the number of +events that are happening and these are + + align:start position:0% +events that are happening and these are + + + align:start position:0% +events that are happening and these are +events of1 billion dollar events these + + align:start position:0% +events of1 billion dollar events these + + + align:start position:0% +events of1 billion dollar events these +are not the smallest storms that you are + + align:start position:0% +are not the smallest storms that you are + + + align:start position:0% +are not the smallest storms that you are +seeing these are actually storms that + + align:start position:0% +seeing these are actually storms that + + + align:start position:0% +seeing these are actually storms that +are causing big damages and then you see + + align:start position:0% +are causing big damages and then you see + + + align:start position:0% +are causing big damages and then you see +in the in the + + align:start position:0% +in the in the + + + align:start position:0% +in the in the +how also + + align:start position:0% +how also + + + align:start position:0% +how also +the the amount of the cost in billions + + align:start position:0% +the the amount of the cost in billions + + + align:start position:0% +the the amount of the cost in billions +of the of those disasters are also going + + align:start position:0% +of the of those disasters are also going + + + align:start position:0% +of the of those disasters are also going +up so those are billions of dollars that + + align:start position:0% +up so those are billions of dollars that + + + align:start position:0% +up so those are billions of dollars that +are happening and they used to be just + + align:start position:0% +are happening and they used to be just + + + align:start position:0% +are happening and they used to be just +this much and they used to be this small + + align:start position:0% +this much and they used to be this small + + + align:start position:0% +this much and they used to be this small +here and now are going all the way up so + + align:start position:0% +here and now are going all the way up so + + + align:start position:0% +here and now are going all the way up so +those billions are being distributed + + align:start position:0% +those billions are being distributed + + + align:start position:0% +those billions are being distributed +ultimately among the public sector among + + align:start position:0% +ultimately among the public sector among + + + align:start position:0% +ultimately among the public sector among +the insurance companies and among the + + align:start position:0% +the insurance companies and among the + + + align:start position:0% +the insurance companies and among the +private sector but it's very clear + + align:start position:0% +private sector but it's very clear + + + align:start position:0% +private sector but it's very clear +that somehow we will all pay in one form + + align:start position:0% +that somehow we will all pay in one form + + + align:start position:0% +that somehow we will all pay in one form +or the other for it because the + + align:start position:0% +or the other for it because the + + + align:start position:0% +or the other for it because the +insurance are not going to keep + + align:start position:0% +insurance are not going to keep + + + align:start position:0% +insurance are not going to keep +absorbing billions and billions of + + align:start position:0% +absorbing billions and billions of + + + align:start position:0% +absorbing billions and billions of +dollars of climate disasters because + + align:start position:0% +dollars of climate disasters because + + + align:start position:0% +dollars of climate disasters because +there is just no way that you can + + align:start position:0% +there is just no way that you can + + + align:start position:0% +there is just no way that you can +actually keep making business sense of + + align:start position:0% +actually keep making business sense of + + + align:start position:0% +actually keep making business sense of +keep absorbing billions of dollars at + + align:start position:0% +keep absorbing billions of dollars at + + + align:start position:0% +keep absorbing billions of dollars at +that in places like Louisiana places + + align:start position:0% +that in places like Louisiana places + + + align:start position:0% +that in places like Louisiana places +like Florida and so forth Kevin uh and I + + align:start position:0% +like Florida and so forth Kevin uh and I + + + align:start position:0% +like Florida and so forth Kevin uh and I +and CI were talking about breakfast how + + align:start position:0% +and CI were talking about breakfast how + + + align:start position:0% +and CI were talking about breakfast how +insurance companies are exiting markets + + align:start position:0% +insurance companies are exiting markets + + + align:start position:0% +insurance companies are exiting markets +like Louisiana just because because + + align:start position:0% +like Louisiana just because because + + + align:start position:0% +like Louisiana just because because +there is just no financial model or no + + align:start position:0% +there is just no financial model or no + + + align:start position:0% +there is just no financial model or no +business sense to keep absorbing a lot + + align:start position:0% +business sense to keep absorbing a lot + + + align:start position:0% +business sense to keep absorbing a lot +of those damages if you have such a + + align:start position:0% +of those damages if you have such a + + + align:start position:0% +of those damages if you have such a +frequency of those disasters in in that + + align:start position:0% +frequency of those disasters in in that + + + align:start position:0% +frequency of those disasters in in that +region so you know for a while they can + + align:start position:0% +region so you know for a while they can + + + align:start position:0% +region so you know for a while they can +be a uh they can give you some bandwidth + + align:start position:0% +be a uh they can give you some bandwidth + + + align:start position:0% +be a uh they can give you some bandwidth +but if this becomes the systematic + + align:start position:0% +but if this becomes the systematic + + + align:start position:0% +but if this becomes the systematic +change there where every year you have + + align:start position:0% +change there where every year you have + + + align:start position:0% +change there where every year you have +to absorb all of those billions and even + + align:start position:0% +to absorb all of those billions and even + + + align:start position:0% +to absorb all of those billions and even +more because you see that the trend is + + align:start position:0% +more because you see that the trend is + + + align:start position:0% +more because you see that the trend is +going upward then ultimately you will go + + align:start position:0% +going upward then ultimately you will go + + + align:start position:0% +going upward then ultimately you will go +bankrupt or you will just decide to exit + + align:start position:0% +bankrupt or you will just decide to exit + + + align:start position:0% +bankrupt or you will just decide to exit +to make to keep making money out of your + + align:start position:0% +to make to keep making money out of your + + + align:start position:0% +to make to keep making money out of your +own business because if you keep just + + align:start position:0% +own business because if you keep just + + + align:start position:0% +own business because if you keep just +absorbing the punches eventually it just + + align:start position:0% +absorbing the punches eventually it just + + + align:start position:0% +absorbing the punches eventually it just +doesn't make any Financial sense so this + + align:start position:0% +doesn't make any Financial sense so this + + + align:start position:0% +doesn't make any Financial sense so this +is the + + align:start position:0% +is the + + + align:start position:0% +is the +situation I hope that you are all + + align:start position:0% +situation I hope that you are all + + + align:start position:0% +situation I hope that you are all +depressed + + align:start position:0% +depressed + + + align:start position:0% +depressed +no When someone tells you that I hope + + align:start position:0% +no When someone tells you that I hope + + + align:start position:0% +no When someone tells you that I hope +that you be depressed you shouldn't + + align:start position:0% +that you be depressed you shouldn't + + + align:start position:0% +that you be depressed you shouldn't +laugh so I'm + + align:start position:0% +laugh so I'm + + + align:start position:0% +laugh so I'm +poite this will also bring bring us a + + align:start position:0% +poite this will also bring bring us a + + + align:start position:0% +poite this will also bring bring us a +lot of + + align:start position:0% +lot of + + + align:start position:0% +lot of +job yeah for + + align:start position:0% +job yeah for + + + align:start position:0% +job yeah for +for for Rebuilders yeah exactly all the + + align:start position:0% +for for Rebuilders yeah exactly all the + + + align:start position:0% +for for Rebuilders yeah exactly all the +real companies they need + + align:start position:0% +real companies they need + + + align:start position:0% +real companies they need +us to start to to start the C the risks + + align:start position:0% +us to start to to start the C the risks + + + align:start position:0% +us to start to to start the C the risks +right yeah job opportunities for those + + align:start position:0% +right yeah job opportunities for those + + + align:start position:0% +right yeah job opportunities for those +that know and understand this yeah yeah + + align:start position:0% +that know and understand this yeah yeah + + + align:start position:0% +that know and understand this yeah yeah +only only from us we know yeah well + + align:start position:0% +only only from us we know yeah well + + + align:start position:0% +only only from us we know yeah well +definitely I mean there is a lot of + + align:start position:0% +definitely I mean there is a lot of + + + align:start position:0% +definitely I mean there is a lot of +people that never got these type of + + align:start position:0% +people that never got these type of + + + align:start position:0% +people that never got these type of +insights and they really they keep + + align:start position:0% +insights and they really they keep + + + align:start position:0% +insights and they really they keep +living in a they keep living and making + + align:start position:0% +living in a they keep living and making + + + align:start position:0% +living in a they keep living and making +decisions in a world that look like this + + align:start position:0% +decisions in a world that look like this + + + align:start position:0% +decisions in a world that look like this +while hopefully after these sessions and + + align:start position:0% +while hopefully after these sessions and + + + align:start position:0% +while hopefully after these sessions and +after this course you understand how to + + align:start position:0% +after this course you understand how to + + + align:start position:0% +after this course you understand how to +make decisions and how to uh think in a + + align:start position:0% +make decisions and how to uh think in a + + + align:start position:0% +make decisions and how to uh think in a +world that looks like + + align:start position:0% +world that looks like + + + align:start position:0% +world that looks like +present so that's where your job + + align:start position:0% +present so that's where your job + + + align:start position:0% +present so that's where your job +opportunities come thinking not like + + align:start position:0% +opportunities come thinking not like + + + align:start position:0% +opportunities come thinking not like +this but thinking like this and this is + + align:start position:0% +this but thinking like this and this is + + + align:start position:0% +this but thinking like this and this is +also one of the sessions Carlos you want + + align:start position:0% +also one of the sessions Carlos you want + + + align:start position:0% +also one of the sessions Carlos you want +to think like this I have a question + + align:start position:0% +to think like this I have a question + + + align:start position:0% +to think like this I have a question +sure looking into the graphs and seeing + + align:start position:0% +sure looking into the graphs and seeing + + + align:start position:0% +sure looking into the graphs and seeing +that the green component which is severe + + align:start position:0% +that the green component which is severe + + + align:start position:0% +that the green component which is severe +storm count is the one that has grown + + align:start position:0% +storm count is the one that has grown + + + align:start position:0% +storm count is the one that has grown +substantially and also looking at the + + align:start position:0% +substantially and also looking at the + + + align:start position:0% +substantially and also looking at the +five average cost line is there any + + align:start position:0% +five average cost line is there any + + + align:start position:0% +five average cost line is there any +correlation between how population has + + align:start position:0% +correlation between how population has + + + align:start position:0% +correlation between how population has +grown into big urban areas and how does + + align:start position:0% +grown into big urban areas and how does + + + align:start position:0% +grown into big urban areas and how does +that has affected indeed the costs of + + align:start position:0% +that has affected indeed the costs of + + + align:start position:0% +that has affected indeed the costs of +this this the the ongoing disasters that + + align:start position:0% +this this the the ongoing disasters that + + + align:start position:0% +this this the the ongoing disasters that +are related with at least with the + + align:start position:0% +are related with at least with the + + + align:start position:0% +are related with at least with the +storms and floodings yeah because I + + align:start position:0% +storms and floodings yeah because I + + + align:start position:0% +storms and floodings yeah because I +imagine I mean it's more costly if you + + align:start position:0% +imagine I mean it's more costly if you + + + align:start position:0% +imagine I mean it's more costly if you +have more people people living in dense + + align:start position:0% +have more people people living in dense + + + align:start position:0% +have more people people living in dense +areas that maybe separated small rural + + align:start position:0% +areas that maybe separated small rural + + + align:start position:0% +areas that maybe separated small rural +suburban concentration of people I don't + + align:start position:0% +suburban concentration of people I don't + + + align:start position:0% +suburban concentration of people I don't +know if it has any anything any + + align:start position:0% +know if it has any anything any + + + align:start position:0% +know if it has any anything any +correlation with the ongoing growing of + + align:start position:0% +correlation with the ongoing growing of + + + align:start position:0% +correlation with the ongoing growing of +costs yeah yeah it will not no that's a + + align:start position:0% +costs yeah yeah it will not no that's a + + + align:start position:0% +costs yeah yeah it will not no that's a +very good point and that's a very good + + align:start position:0% +very good point and that's a very good + + + align:start position:0% +very good point and that's a very good +question so it it will not explain the + + align:start position:0% +question so it it will not explain the + + + align:start position:0% +question so it it will not explain the +the the total amount of Damages but it + + align:start position:0% +the the total amount of Damages but it + + + align:start position:0% +the the total amount of Damages but it +is true that one of the failures of + + align:start position:0% +is true that one of the failures of + + + align:start position:0% +is true that one of the failures of +market failures that are creating that + + align:start position:0% +market failures that are creating that + + + align:start position:0% +market failures that are creating that +the that the damages are more sever here + + align:start position:0% +the that the damages are more sever here + + + align:start position:0% +the that the damages are more sever here +is that we keep letting people develop + + align:start position:0% +is that we keep letting people develop + + + align:start position:0% +is that we keep letting people develop +in areas that we know are at risk of + + align:start position:0% +in areas that we know are at risk of + + + align:start position:0% +in areas that we know are at risk of +floating we know that are at risk of + + align:start position:0% +floating we know that are at risk of + + + align:start position:0% +floating we know that are at risk of +suffering some of those uh events so it + + align:start position:0% +suffering some of those uh events so it + + + align:start position:0% +suffering some of those uh events so it +doesn't make sense that if you think + + align:start position:0% +doesn't make sense that if you think + + + align:start position:0% +doesn't make sense that if you think +about areas that are at very high risk + + align:start position:0% +about areas that are at very high risk + + + align:start position:0% +about areas that are at very high risk +of um of suffering a wildfire or + + align:start position:0% +of um of suffering a wildfire or + + + align:start position:0% +of um of suffering a wildfire or +suffering a storm that you keep letting + + align:start position:0% +suffering a storm that you keep letting + + + align:start position:0% +suffering a storm that you keep letting +people develop in those areas and you + + align:start position:0% +people develop in those areas and you + + + align:start position:0% +people develop in those areas and you +have for example the United State you + + align:start position:0% +have for example the United State you + + + align:start position:0% +have for example the United State you +have the FEMA Maps where you have a very + + align:start position:0% +have the FEMA Maps where you have a very + + + align:start position:0% +have the FEMA Maps where you have a very +accurate uh view on what are risky areas + + align:start position:0% +accurate uh view on what are risky areas + + + align:start position:0% +accurate uh view on what are risky areas +where are not risky areas and in a lot + + align:start position:0% +where are not risky areas and in a lot + + + align:start position:0% +where are not risky areas and in a lot +of places we let people develop as that + + align:start position:0% +of places we let people develop as that + + + align:start position:0% +of places we let people develop as that +risk is not there and we let people + + align:start position:0% +risk is not there and we let people + + + align:start position:0% +risk is not there and we let people +develop in areas where we know that + + align:start position:0% +develop in areas where we know that + + + align:start position:0% +develop in areas where we know that +sooner than later there will be + + align:start position:0% +sooner than later there will be + + + align:start position:0% +sooner than later there will be +something that will blow away uh those + + align:start position:0% +something that will blow away uh those + + + align:start position:0% +something that will blow away uh those +houses and therefore the damages and the + + align:start position:0% +houses and therefore the damages and the + + + align:start position:0% +houses and therefore the damages and the +human lives that are involved in that + + align:start position:0% +human lives that are involved in that + + + align:start position:0% +human lives that are involved in that +are at are at risk so we definitely need + + align:start position:0% +are at are at risk so we definitely need + + + align:start position:0% +are at are at risk so we definitely need +to rethink about different zoning areas + + align:start position:0% +to rethink about different zoning areas + + + align:start position:0% +to rethink about different zoning areas +that are um helping to mitigate those + + align:start position:0% +that are um helping to mitigate those + + + align:start position:0% +that are um helping to mitigate those +Risk by a avoiding that people are + + align:start position:0% +Risk by a avoiding that people are + + + align:start position:0% +Risk by a avoiding that people are +exposed to certain things in certain + + align:start position:0% +exposed to certain things in certain + + + align:start position:0% +exposed to certain things in certain +areas that we know are at + + align:start position:0% +areas that we know are at + + + align:start position:0% +areas that we know are at +disproportionately high risk of + + align:start position:0% +disproportionately high risk of + + + align:start position:0% +disproportionately high risk of +suffering a wildfire uh floating and so + + align:start position:0% +suffering a wildfire uh floating and so + + + align:start position:0% +suffering a wildfire uh floating and so +forth so this is part of the problem + + align:start position:0% +forth so this is part of the problem + + + align:start position:0% +forth so this is part of the problem +that we let people keep developing next + + align:start position:0% +that we let people keep developing next + + + align:start position:0% +that we let people keep developing next +to the coastal line we need to people + + align:start position:0% +to the coastal line we need to people + + + align:start position:0% +to the coastal line we need to people +and while we don't put infrastructure in + + align:start position:0% +and while we don't put infrastructure in + + + align:start position:0% +and while we don't put infrastructure in +place to to prevent the floting we let + + align:start position:0% +place to to prevent the floting we let + + + align:start position:0% +place to to prevent the floting we let +people to be uh leing next to River + + align:start position:0% +people to be uh leing next to River + + + align:start position:0% +people to be uh leing next to River +Flows that are at risk of floating when + + align:start position:0% +Flows that are at risk of floating when + + + align:start position:0% +Flows that are at risk of floating when +there the severe storms happening uh but + + align:start position:0% +there the severe storms happening uh but + + + align:start position:0% +there the severe storms happening uh but +part A lot of it is that as you see uh + + align:start position:0% +part A lot of it is that as you see uh + + + align:start position:0% +part A lot of it is that as you see uh +in the uh let me go back as you see in + + align:start position:0% +in the uh let me go back as you see in + + + align:start position:0% +in the uh let me go back as you see in +this map those events this is only for + + align:start position:0% +this map those events this is only for + + + align:start position:0% +this map those events this is only for +heat WS but that happens everywhere in + + align:start position:0% +heat WS but that happens everywhere in + + + align:start position:0% +heat WS but that happens everywhere in +in a lot of those events too those + + align:start position:0% +in a lot of those events too those + + + align:start position:0% +in a lot of those events too those +events are being more and more + + align:start position:0% +events are being more and more + + + align:start position:0% +events are being more and more +widespread and they are going more and + + align:start position:0% +widespread and they are going more and + + + align:start position:0% +widespread and they are going more and +more and they are more and more + + align:start position:0% +more and they are more and more + + + align:start position:0% +more and they are more and more +damaging uh year after year so that is + + align:start position:0% +damaging uh year after year so that is + + + align:start position:0% +damaging uh year after year so that is +uh that is the big part of that graph + + align:start position:0% +uh that is the big part of that graph + + + align:start position:0% +uh that is the big part of that graph +that something that if you see here if + + align:start position:0% +that something that if you see here if + + + align:start position:0% +that something that if you see here if +you think about Latin America here you + + align:start position:0% +you think about Latin America here you + + + align:start position:0% +you think about Latin America here you +see that it used to be it starts in blue + + align:start position:0% +see that it used to be it starts in blue + + + align:start position:0% +see that it used to be it starts in blue +and it's really nothing there but as you + + align:start position:0% +and it's really nothing there but as you + + + align:start position:0% +and it's really nothing there but as you +go on you see that it starts to be part + + align:start position:0% +go on you see that it starts to be part + + + align:start position:0% +go on you see that it starts to be part +of Latin America and now as as the graph + + align:start position:0% +of Latin America and now as as the graph + + + align:start position:0% +of Latin America and now as as the graph +goes on is the entire Latin America that + + align:start position:0% +goes on is the entire Latin America that + + + align:start position:0% +goes on is the entire Latin America that +is affected by heat waves so it is going + + align:start position:0% +is affected by heat waves so it is going + + + align:start position:0% +is affected by heat waves so it is going +more and more widespread and it's going + + align:start position:0% +more and more widespread and it's going + + + align:start position:0% +more and more widespread and it's going +more and more damaging and that is what + + align:start position:0% +more and more damaging and that is what + + + align:start position:0% +more and more damaging and that is what +is causing this uh this TR to go up + + align:start position:0% +is causing this uh this TR to go up + + + align:start position:0% +is causing this uh this TR to go up +together with the idea that we don't let + + align:start position:0% +together with the idea that we don't let + + + align:start position:0% +together with the idea that we don't let +people be protected given that we seems + + align:start position:0% +people be protected given that we seems + + + align:start position:0% +people be protected given that we seems +that we don't learn from the past and + + align:start position:0% +that we don't learn from the past and + + + align:start position:0% +that we don't learn from the past and +then we keep letting them leave whatever + + align:start position:0% +then we keep letting them leave whatever + + + align:start position:0% +then we keep letting them leave whatever +a developer decides them to to leave or + + align:start position:0% +a developer decides them to to leave or + + + align:start position:0% +a developer decides them to to leave or +then themselves decide to build up a + + align:start position:0% +then themselves decide to build up a + + + align:start position:0% +then themselves decide to build up a +partiel of land and we will talk about + + align:start position:0% +partiel of land and we will talk about + + + align:start position:0% +partiel of land and we will talk about +resiliency and we will talk about those + + align:start position:0% +resiliency and we will talk about those + + + align:start position:0% +resiliency and we will talk about those +things later too Bill that point and if + + align:start position:0% +things later too Bill that point and if + + + align:start position:0% +things later too Bill that point and if +you're going to touch on it later um + + align:start position:0% +you're going to touch on it later um + + + align:start position:0% +you're going to touch on it later um +then feel free to just + + align:start position:0% +then feel free to just + + + align:start position:0% +then feel free to just +skip we're dealing with finite amounts + + align:start position:0% +skip we're dealing with finite amounts + + + align:start position:0% +skip we're dealing with finite amounts +of public funds private sector funds and + + align:start position:0% +of public funds private sector funds and + + + align:start position:0% +of public funds private sector funds and +like you said there's already people + + align:start position:0% +like you said there's already people + + + align:start position:0% +like you said there's already people +living next to that River that's going + + align:start position:0% +living next to that River that's going + + + align:start position:0% +living next to that River that's going +to start overflowing + + align:start position:0% +to start overflowing + + + align:start position:0% +to start overflowing +five years rather than every 100 years + + align:start position:0% +five years rather than every 100 years + + + align:start position:0% +five years rather than every 100 years +where do you put money into adaptation + + align:start position:0% +where do you put money into adaptation + + + align:start position:0% +where do you put money into adaptation +and where do you put money into + + align:start position:0% +and where do you put money into + + + align:start position:0% +and where do you put money into +mitigation is that is it context context + + align:start position:0% +mitigation is that is it context context + + + align:start position:0% +mitigation is that is it context context +specific yeah that's a very good point a + + align:start position:0% +specific yeah that's a very good point a + + + align:start position:0% +specific yeah that's a very good point a +lot of it this comes down to political + + align:start position:0% +lot of it this comes down to political + + + align:start position:0% +lot of it this comes down to political +decision of what do you want to do and a + + align:start position:0% +decision of what do you want to do and a + + + align:start position:0% +decision of what do you want to do and a +lot of it we will talk about beliefs + + align:start position:0% +lot of it we will talk about beliefs + + + align:start position:0% +lot of it we will talk about beliefs +about climate change and so forth so + + align:start position:0% +about climate change and so forth so + + + align:start position:0% +about climate change and so forth so +then there is also some belief story + + align:start position:0% +then there is also some belief story + + + align:start position:0% +then there is also some belief story +there uh we will talk about uh later + + align:start position:0% +there uh we will talk about uh later + + + align:start position:0% +there uh we will talk about uh later +today or early on um on Thursday I think + + align:start position:0% +today or early on um on Thursday I think + + + align:start position:0% +today or early on um on Thursday I think +it will be early on Thursday given the + + align:start position:0% +it will be early on Thursday given the + + + align:start position:0% +it will be early on Thursday given the +the data and I want to give Kevin enough + + align:start position:0% +the data and I want to give Kevin enough + + + align:start position:0% +the data and I want to give Kevin enough +time to talk about resiliency investment + + align:start position:0% +time to talk about resiliency investment + + + align:start position:0% +time to talk about resiliency investment +so we will talk we will go through the + + align:start position:0% +so we will talk we will go through the + + + align:start position:0% +so we will talk we will go through the +case of Boston Seaport and how do we + + align:start position:0% +case of Boston Seaport and how do we + + + align:start position:0% +case of Boston Seaport and how do we +make those decisions uh all going down + + align:start position:0% +make those decisions uh all going down + + + align:start position:0% +make those decisions uh all going down +to the valuation of of those disasters + + align:start position:0% +to the valuation of of those disasters + + + align:start position:0% +to the valuation of of those disasters +and the valuation of uh the + + align:start position:0% +and the valuation of uh the + + + align:start position:0% +and the valuation of uh the +spected uh + + align:start position:0% +spected uh + + + align:start position:0% +spected uh +defensive uh effectiveness of the + + align:start position:0% +defensive uh effectiveness of the + + + align:start position:0% +defensive uh effectiveness of the +effectiveness of defensive Investments + + align:start position:0% +effectiveness of defensive Investments + + + align:start position:0% +effectiveness of defensive Investments +that we are going to do with different + + align:start position:0% +that we are going to do with different + + + align:start position:0% +that we are going to do with different +city walls and so forth and then you are + + align:start position:0% +city walls and so forth and then you are + + + align:start position:0% +city walls and so forth and then you are +going to see how those decisions are + + align:start position:0% +going to see how those decisions are + + + align:start position:0% +going to see how those decisions are +being influenced by mitigation versus + + align:start position:0% +being influenced by mitigation versus + + + align:start position:0% +being influenced by mitigation versus +adaptation preferences and also your + + align:start position:0% +adaptation preferences and also your + + + align:start position:0% +adaptation preferences and also your +beliefs about different risk associated + + align:start position:0% +beliefs about different risk associated + + + align:start position:0% +beliefs about different risk associated +with it and so forth and there we can we + + align:start position:0% +with it and so forth and there we can we + + + align:start position:0% +with it and so forth and there we can we +can talk more about it with those + + align:start position:0% +can talk more about it with those + + + align:start position:0% +can talk more about it with those +numbers in front of it anyone else + + align:start position:0% +numbers in front of it anyone else + + + align:start position:0% +numbers in front of it anyone else +David + + align:start position:0% + + + + align:start position:0% + +that + + align:start position:0% +that + + + align:start position:0% +that +uh7 yeah + + align:start position:0% + + + + align:start position:0% + +pretty 1 was either Harvey Orma but + + align:start position:0% +pretty 1 was either Harvey Orma but + + + align:start position:0% +pretty 1 was either Harvey Orma but +there was of + + align:start position:0% + + + + align:start position:0% + +wild great so one of the things that I + + align:start position:0% +wild great so one of the things that I + + + align:start position:0% +wild great so one of the things that I +want to do uh now is all of + + align:start position:0% +want to do uh now is all of + + + align:start position:0% +want to do uh now is all of +those disasters have some implications + + align:start position:0% +those disasters have some implications + + + align:start position:0% +those disasters have some implications +for real estate and now what we are + + align:start position:0% +for real estate and now what we are + + + align:start position:0% +for real estate and now what we are +going to do is also thinking about uh + + align:start position:0% +going to do is also thinking about uh + + + align:start position:0% +going to do is also thinking about uh +how those type of disasters are going to + + align:start position:0% +how those type of disasters are going to + + + align:start position:0% +how those type of disasters are going to +translate Ely to the bottom line one of + + align:start position:0% +translate Ely to the bottom line one of + + + align:start position:0% +translate Ely to the bottom line one of +the first steps is to start classifying + + align:start position:0% +the first steps is to start classifying + + + align:start position:0% +the first steps is to start classifying +those disasters it's not the same for uh + + align:start position:0% +those disasters it's not the same for uh + + + align:start position:0% +those disasters it's not the same for uh +a for the buil environment and for an + + align:start position:0% +a for the buil environment and for an + + + align:start position:0% +a for the buil environment and for an +investment in real estate to be thinking + + align:start position:0% +investment in real estate to be thinking + + + align:start position:0% +investment in real estate to be thinking +about exposure to a heat wve to being + + align:start position:0% +about exposure to a heat wve to being + + + align:start position:0% +about exposure to a heat wve to being +exposed to a wildfire or to being + + align:start position:0% +exposed to a wildfire or to being + + + align:start position:0% +exposed to a wildfire or to being +exposed to uh sea level rise or floting + + align:start position:0% +exposed to uh sea level rise or floting + + + align:start position:0% +exposed to uh sea level rise or floting +some of them have direct risk of uh + + align:start position:0% +some of them have direct risk of uh + + + align:start position:0% +some of them have direct risk of uh +destroying our properties some of them + + align:start position:0% +destroying our properties some of them + + + align:start position:0% +destroying our properties some of them +will have uh implications for the cost + + align:start position:0% +will have uh implications for the cost + + + align:start position:0% +will have uh implications for the cost +operating cost of that property some of + + align:start position:0% +operating cost of that property some of + + + align:start position:0% +operating cost of that property some of +them are actually things that are uh + + align:start position:0% +them are actually things that are uh + + + align:start position:0% +them are actually things that are uh +related to to risk and some of them are + + align:start position:0% +related to to risk and some of them are + + + align:start position:0% +related to to risk and some of them are +thinking related to um um to + + align:start position:0% +thinking related to um um to + + + align:start position:0% +thinking related to um um to +experiencing this amenities and this + + align:start position:0% +experiencing this amenities and this + + + align:start position:0% +experiencing this amenities and this +utility of being in that place uh if you + + align:start position:0% +utility of being in that place uh if you + + + align:start position:0% +utility of being in that place uh if you +look at the the classification that is + + align:start position:0% +look at the the classification that is + + + align:start position:0% +look at the the classification that is +usually taken in the real estate + + align:start position:0% +usually taken in the real estate + + + align:start position:0% +usually taken in the real estate +industry and if you see the reports of + + align:start position:0% +industry and if you see the reports of + + + align:start position:0% +industry and if you see the reports of +Uli and other other big thing tanks you + + align:start position:0% +Uli and other other big thing tanks you + + + align:start position:0% +Uli and other other big thing tanks you +will see that you have a classification + + align:start position:0% +will see that you have a classification + + + align:start position:0% +will see that you have a classification +of physical risk that is divided into + + align:start position:0% +of physical risk that is divided into + + + align:start position:0% +of physical risk that is divided into +two you have acute climate risk that is + + align:start position:0% +two you have acute climate risk that is + + + align:start position:0% +two you have acute climate risk that is +basically all of these catastrophic + + align:start position:0% +basically all of these catastrophic + + + align:start position:0% +basically all of these catastrophic +events these one billion dollar events + + align:start position:0% +events these one billion dollar events + + + align:start position:0% +events these one billion dollar events +that I showed you in the previous slide + + align:start position:0% +that I showed you in the previous slide + + + align:start position:0% +that I showed you in the previous slide +but you also have more chronic climate + + align:start position:0% +but you also have more chronic climate + + + align:start position:0% +but you also have more chronic climate +risk that are basically this disamenity + + align:start position:0% +risk that are basically this disamenity + + + align:start position:0% +risk that are basically this disamenity +like the increasing heat waves and also + + align:start position:0% +like the increasing heat waves and also + + + align:start position:0% +like the increasing heat waves and also +sea level rise those things that are not + + align:start position:0% +sea level rise those things that are not + + + align:start position:0% +sea level rise those things that are not +necessarily things that will generate a + + align:start position:0% +necessarily things that will generate a + + + align:start position:0% +necessarily things that will generate a +an impact as of now but it's actually + + align:start position:0% +an impact as of now but it's actually + + + align:start position:0% +an impact as of now but it's actually +increasing the risk of a lot of other + + align:start position:0% +increasing the risk of a lot of other + + + align:start position:0% +increasing the risk of a lot of other +stuff to happen so that's a big + + align:start position:0% +stuff to happen so that's a big + + + align:start position:0% +stuff to happen so that's a big +different then we have the transition + + align:start position:0% +different then we have the transition + + + align:start position:0% +different then we have the transition +risk that is a lot of the things that we + + align:start position:0% +risk that is a lot of the things that we + + + align:start position:0% +risk that is a lot of the things that we +also cover in the first block uh + + align:start position:0% +also cover in the first block uh + + + align:start position:0% +also cover in the first block uh +regulatory changes Market changes that + + align:start position:0% +regulatory changes Market changes that + + + align:start position:0% +regulatory changes Market changes that +will actually make those assets be less + + align:start position:0% +will actually make those assets be less + + + align:start position:0% +will actually make those assets be less +attractive so it's not only here we have + + align:start position:0% +attractive so it's not only here we have + + + align:start position:0% +attractive so it's not only here we have +like kind of the physical race is sort + + align:start position:0% +like kind of the physical race is sort + + + align:start position:0% +like kind of the physical race is sort +of risk is sort of the first order + + align:start position:0% +of risk is sort of the first order + + + align:start position:0% +of risk is sort of the first order +effect so once my asset is hit by that + + align:start position:0% +effect so once my asset is hit by that + + + align:start position:0% +effect so once my asset is hit by that +event how will that respond but also you + + align:start position:0% +event how will that respond but also you + + + align:start position:0% +event how will that respond but also you +have all the market responses associated + + align:start position:0% +have all the market responses associated + + + align:start position:0% +have all the market responses associated +with people believing that that uh heat + + align:start position:0% +with people believing that that uh heat + + + align:start position:0% +with people believing that that uh heat +will happen more often and will be more + + align:start position:0% +will happen more often and will be more + + + align:start position:0% +will happen more often and will be more +severe these are the two things that we + + align:start position:0% +severe these are the two things that we + + + align:start position:0% +severe these are the two things that we +are going to cover in the course and + + align:start position:0% +are going to cover in the course and + + + align:start position:0% +are going to cover in the course and +especially actually thinking about the + + align:start position:0% +especially actually thinking about the + + + align:start position:0% +especially actually thinking about the +market risk and transition RIS so before + + align:start position:0% +market risk and transition RIS so before + + + align:start position:0% +market risk and transition RIS so before +we want to be preventive here and we + + align:start position:0% +we want to be preventive here and we + + + align:start position:0% +we want to be preventive here and we +want to actually teach you how to avoid + + align:start position:0% +want to actually teach you how to avoid + + + align:start position:0% +want to actually teach you how to avoid +the punches so we actually want to teach + + align:start position:0% +the punches so we actually want to teach + + + align:start position:0% +the punches so we actually want to teach +you how to be ahead of of those severe + + align:start position:0% +you how to be ahead of of those severe + + + align:start position:0% +you how to be ahead of of those severe +events and actually how to cope with + + align:start position:0% +events and actually how to cope with + + + align:start position:0% +events and actually how to cope with +them using Market signals and Market + + align:start position:0% +them using Market signals and Market + + + align:start position:0% +them using Market signals and Market +strategies um there are few things here + + align:start position:0% +strategies um there are few things here + + + align:start position:0% +strategies um there are few things here +that you you want to uh think about it's + + align:start position:0% +that you you want to uh think about it's + + + align:start position:0% +that you you want to uh think about it's +a lot of the the things of raising sea + + align:start position:0% +a lot of the the things of raising sea + + + align:start position:0% +a lot of the the things of raising sea +levels raising average temperatures have + + align:start position:0% +levels raising average temperatures have + + + align:start position:0% +levels raising average temperatures have +to do with things that are happening on + + align:start position:0% +to do with things that are happening on + + + align:start position:0% +to do with things that are happening on +on a very continuous basis day year + + align:start position:0% +on a very continuous basis day year + + + align:start position:0% +on a very continuous basis day year +after years you have more higher + + align:start position:0% +after years you have more higher + + + align:start position:0% +after years you have more higher +temperatures year after years you have + + align:start position:0% +temperatures year after years you have + + + align:start position:0% +temperatures year after years you have +also a higher level of sea rise those + + align:start position:0% +also a higher level of sea rise those + + + align:start position:0% +also a higher level of sea rise those +are things that we are experiencing we + + align:start position:0% +are things that we are experiencing we + + + align:start position:0% +are things that we are experiencing we +can actually almost continuously + + align:start position:0% +can actually almost continuously + + + align:start position:0% +can actually almost continuously +incorporate it into this and then you + + align:start position:0% +incorporate it into this and then you + + + align:start position:0% +incorporate it into this and then you +have a lot of things that are + + align:start position:0% +have a lot of things that are + + + align:start position:0% +have a lot of things that are +catastrophic events that will happen + + align:start position:0% +catastrophic events that will happen + + + align:start position:0% +catastrophic events that will happen +every 10 years every 15 years and those + + align:start position:0% +every 10 years every 15 years and those + + + align:start position:0% +every 10 years every 15 years and those +are thinkings are those are events that + + align:start position:0% +are thinkings are those are events that + + + align:start position:0% +are thinkings are those are events that +are related to to risk you don't + + align:start position:0% +are related to to risk you don't + + + align:start position:0% +are related to to risk you don't +experience them on a daily basis you + + align:start position:0% +experience them on a daily basis you + + + align:start position:0% +experience them on a daily basis you +don't experience them on an hour bases + + align:start position:0% +don't experience them on an hour bases + + + align:start position:0% +don't experience them on an hour bases +those are things that are the risk to + + align:start position:0% +those are things that are the risk to + + + align:start position:0% +those are things that are the risk to +happen a very severe bad things in 10 15 + + align:start position:0% +happen a very severe bad things in 10 15 + + + align:start position:0% +happen a very severe bad things in 10 15 +20 years + + align:start position:0% +20 years + + + align:start position:0% +20 years +um let me skip this and now we want to + + align:start position:0% +um let me skip this and now we want to + + + align:start position:0% +um let me skip this and now we want to +do in the last 10 minutes of of of this + + align:start position:0% +do in the last 10 minutes of of of this + + + align:start position:0% +do in the last 10 minutes of of of this +I want to + + align:start position:0% +I want to + + + align:start position:0% +I want to +actually use one of the key tools that + + align:start position:0% +actually use one of the key tools that + + + align:start position:0% +actually use one of the key tools that +you learn in real estate economics to + + align:start position:0% +you learn in real estate economics to + + + align:start position:0% +you learn in real estate economics to +understand how all of these translates + + align:start position:0% +understand how all of these translates + + + align:start position:0% +understand how all of these translates +into real estate markets and real estate + + align:start position:0% +into real estate markets and real estate + + + align:start position:0% +into real estate markets and real estate +uh building and asset values um there is + + align:start position:0% +uh building and asset values um there is + + + align:start position:0% +uh building and asset values um there is +a lot of and the reason why this is + + align:start position:0% +a lot of and the reason why this is + + + align:start position:0% +a lot of and the reason why this is +important is that there is a lot of + + align:start position:0% +important is that there is a lot of + + + align:start position:0% +important is that there is a lot of +literature every year every month you + + align:start position:0% +literature every year every month you + + + align:start position:0% +literature every year every month you +get a new paper showing that there is + + align:start position:0% +get a new paper showing that there is + + + align:start position:0% +get a new paper showing that there is +this climate event or This Disaster that + + align:start position:0% +this climate event or This Disaster that + + + align:start position:0% +this climate event or This Disaster that +is linked to a drop in value and so + + align:start position:0% +is linked to a drop in value and so + + + align:start position:0% +is linked to a drop in value and so +forth so there is a lot of different + + align:start position:0% +forth so there is a lot of different + + + align:start position:0% +forth so there is a lot of different +scatter pieces out there and it will + + align:start position:0% +scatter pieces out there and it will + + + align:start position:0% +scatter pieces out there and it will +happen more and more over the years so + + align:start position:0% +happen more and more over the years so + + + align:start position:0% +happen more and more over the years so +when you graduate and when you need to + + align:start position:0% +when you graduate and when you need to + + + align:start position:0% +when you graduate and when you need to +incorporate those things there will be a + + align:start position:0% +incorporate those things there will be a + + + align:start position:0% +incorporate those things there will be a +tons of new papers and what we need to + + align:start position:0% +tons of new papers and what we need to + + + align:start position:0% +tons of new papers and what we need to +do here is to give you a good framework + + align:start position:0% +do here is to give you a good framework + + + align:start position:0% +do here is to give you a good framework +and a good way to understand how those + + align:start position:0% +and a good way to understand how those + + + align:start position:0% +and a good way to understand how those +translates ultimately into asset values + + align:start position:0% +translates ultimately into asset values + + + align:start position:0% +translates ultimately into asset values +and how those actually connect with each + + align:start position:0% +and how those actually connect with each + + + align:start position:0% +and how those actually connect with each +other and in a way that if you see that + + align:start position:0% +other and in a way that if you see that + + + align:start position:0% +other and in a way that if you see that +on the one side tenants are affected how + + align:start position:0% +on the one side tenants are affected how + + + align:start position:0% +on the one side tenants are affected how +you actually think from your developer + + align:start position:0% +you actually think from your developer + + + align:start position:0% +you actually think from your developer +chair about the consequences of of your + + align:start position:0% +chair about the consequences of of your + + + align:start position:0% +chair about the consequences of of your +decisions so one of the things that I + + align:start position:0% +decisions so one of the things that I + + + align:start position:0% +decisions so one of the things that I +want to do is get someone to help me + + align:start position:0% +want to do is get someone to help me + + + align:start position:0% +want to do is get someone to help me +understand the four quadrant model so + + align:start position:0% +understand the four quadrant model so + + + align:start position:0% +understand the four quadrant model so +who can tell me what it is and who can + + align:start position:0% +who can tell me what it is and who can + + + align:start position:0% +who can tell me what it is and who can +tell me who is in each of the spaces so + + align:start position:0% +tell me who is in each of the spaces so + + + align:start position:0% +tell me who is in each of the spaces so +who is in in this space you start here + + align:start position:0% +who is in in this space you start here + + + align:start position:0% +who is in in this space you start here +from the top right who is in this space + + align:start position:0% +from the top right who is in this space + + + align:start position:0% +from the top right who is in this space +who meets in this space the developer + + align:start position:0% +who meets in this space the developer + + + align:start position:0% +who meets in this space the developer +the construction company the tenants the + + align:start position:0% +the construction company the tenants the + + + align:start position:0% +the construction company the tenants the +banks landlords and tenants all right + + align:start position:0% +banks landlords and tenants all right + + + align:start position:0% +banks landlords and tenants all right +and how do they relate to each other + + align:start position:0% +and how do they relate to each other + + + align:start position:0% +and how do they relate to each other +Julio what are they doing here what is + + align:start position:0% +Julio what are they doing here what is + + + align:start position:0% +Julio what are they doing here what is +this curve telling me I see a stock I + + align:start position:0% +this curve telling me I see a stock I + + + align:start position:0% +this curve telling me I see a stock I +see rent who decides what that's a + + align:start position:0% +see rent who decides what that's a + + + align:start position:0% +see rent who decides what that's a +demand curve now have it's showing the + + align:start position:0% +demand curve now have it's showing the + + + align:start position:0% +demand curve now have it's showing the +but you also have + + align:start position:0% + + + + align:start position:0% + +supp so the supply the way that we + + align:start position:0% +supp so the supply the way that we + + + align:start position:0% +supp so the supply the way that we +usually start is that the supply is + + align:start position:0% +usually start is that the supply is + + + align:start position:0% +usually start is that the supply is +fixed right we don't move they building + + align:start position:0% +fixed right we don't move they building + + + align:start position:0% +fixed right we don't move they building +a stock from year to year it takes some + + align:start position:0% +a stock from year to year it takes some + + + align:start position:0% +a stock from year to year it takes some +time to build housing to build buildings + + align:start position:0% +time to build housing to build buildings + + + align:start position:0% +time to build housing to build buildings +so this s0 is a starting point and then + + align:start position:0% +so this s0 is a starting point and then + + + align:start position:0% +so this s0 is a starting point and then +given the the demand for a space of + + align:start position:0% +given the the demand for a space of + + + align:start position:0% +given the the demand for a space of +tenants this is the amount of rent that + + align:start position:0% +tenants this is the amount of rent that + + + align:start position:0% +tenants this is the amount of rent that +they will + + align:start position:0% +they will + + + align:start position:0% +they will +pay if the if the if the tenants want + + align:start position:0% +pay if the if the if the tenants want + + + align:start position:0% +pay if the if the if the tenants want +more space then this this line will go + + align:start position:0% +more space then this this line will go + + + align:start position:0% +more space then this this line will go +to the right if the tenants will go less + + align:start position:0% +to the right if the tenants will go less + + + align:start position:0% +to the right if the tenants will go less +will need less space this tenant this + + align:start position:0% +will need less space this tenant this + + + align:start position:0% +will need less space this tenant this +Curve will move inwards so if you think + + align:start position:0% +Curve will move inwards so if you think + + + align:start position:0% +Curve will move inwards so if you think +about now this working from home and so + + align:start position:0% +about now this working from home and so + + + align:start position:0% +about now this working from home and so +forth these tenants will actually demand + + align:start position:0% +forth these tenants will actually demand + + + align:start position:0% +forth these tenants will actually demand +less space so this Curve will go inward + + align:start position:0% +less space so this Curve will go inward + + + align:start position:0% +less space so this Curve will go inward +so forever for whatever the amount of + + align:start position:0% +so forever for whatever the amount of + + + align:start position:0% +so forever for whatever the amount of +buildings are in a city like New York I + + align:start position:0% +buildings are in a city like New York I + + + align:start position:0% +buildings are in a city like New York I +will need less space that I used to be + + align:start position:0% +will need less space that I used to be + + + align:start position:0% +will need less space that I used to be +okay so now we have a supplying meeting + + align:start position:0% +okay so now we have a supplying meeting + + + align:start position:0% +okay so now we have a supplying meeting +the tenants what about the asset + + align:start position:0% +the tenants what about the asset + + + align:start position:0% +the tenants what about the asset +Market what who meets there it's uh + + align:start position:0% +Market what who meets there it's uh + + + align:start position:0% +Market what who meets there it's uh +buyers and sellers so given that level + + align:start position:0% +buyers and sellers so given that level + + + align:start position:0% +buyers and sellers so given that level +we just established you then determ what + + align:start position:0% +we just established you then determ what + + + align:start position:0% +we just established you then determ what +the market prices for transactions so if + + align:start position:0% +the market prices for transactions so if + + + align:start position:0% +the market prices for transactions so if +you're like you said if your rent + + align:start position:0% +you're like you said if your rent + + + align:start position:0% +you're like you said if your rent +increases the price increases but if + + align:start position:0% +increases the price increases but if + + + align:start position:0% +increases the price increases but if +it's decreasing the price will decrease + + align:start position:0% +it's decreasing the price will decrease + + + align:start position:0% +it's decreasing the price will decrease +fewer transactions and how do we think + + align:start position:0% +fewer transactions and how do we think + + + align:start position:0% +fewer transactions and how do we think +about movements in these curve what + + align:start position:0% +about movements in these curve what + + + align:start position:0% +about movements in these curve what +makes that + + align:start position:0% +makes that + + + align:start position:0% +makes that +move here movees that curve stronger + + align:start position:0% +move here movees that curve stronger + + + align:start position:0% +move here movees that curve stronger +stronger fundamentals in the market so + + align:start position:0% +stronger fundamentals in the market so + + + align:start position:0% +stronger fundamentals in the market so +higher rents me higher value or lower + + align:start position:0% +higher rents me higher value or lower + + + align:start position:0% +higher rents me higher value or lower +rent be lower value yeah but that will + + align:start position:0% +rent be lower value yeah but that will + + + align:start position:0% +rent be lower value yeah but that will +be movements along the curve right so if + + align:start position:0% +be movements along the curve right so if + + + align:start position:0% +be movements along the curve right so if +this rent will be here then that price + + align:start position:0% +this rent will be here then that price + + + align:start position:0% +this rent will be here then that price +will be there but how should we think + + align:start position:0% +will be there but how should we think + + + align:start position:0% +will be there but how should we think +about movements in this curve What would + + align:start position:0% +about movements in this curve What would + + + align:start position:0% +about movements in this curve What would +make that for a given rent the price + + align:start position:0% +make that for a given rent the price + + + align:start position:0% +make that for a given rent the price +will be higher or for a given rent the + + align:start position:0% +will be higher or for a given rent the + + + align:start position:0% +will be higher or for a given rent the +price will be lower changes in Cates + + align:start position:0% +price will be lower changes in Cates + + + align:start position:0% +price will be lower changes in Cates +okay and what generates changes in C + + align:start position:0% +okay and what generates changes in C + + + align:start position:0% +okay and what generates changes in C +Rate underly + + align:start position:0% +Rate underly + + + align:start position:0% +Rate underly +Financial systems + + align:start position:0% +Financial systems + + + align:start position:0% +Financial systems +economics interest rates okay so and + + align:start position:0% +economics interest rates okay so and + + + align:start position:0% +economics interest rates okay so and +what about asset a + + align:start position:0% +what about asset a + + + align:start position:0% +what about asset a +specific uh + + align:start position:0% +specific uh + + + align:start position:0% +specific uh +perception risk what happens if the risk + + align:start position:0% +perception risk what happens if the risk + + + align:start position:0% +perception risk what happens if the risk +of an asset is + + align:start position:0% +of an asset is + + + align:start position:0% +of an asset is +higher or perceive as higher rate would + + align:start position:0% +higher or perceive as higher rate would + + + align:start position:0% +higher or perceive as higher rate would +increase and that means that the this + + align:start position:0% +increase and that means that the this + + + align:start position:0% +increase and that means that the this +guy will be here right because for a + + align:start position:0% +guy will be here right because for a + + + align:start position:0% +guy will be here right because for a +given rent the high the risk will be + + align:start position:0% +given rent the high the risk will be + + + align:start position:0% +given rent the high the risk will be +higher and therefore the more reluctant + + align:start position:0% +higher and therefore the more reluctant + + + align:start position:0% +higher and therefore the more reluctant +I will be to hold that asset because at + + align:start position:0% +I will be to hold that asset because at + + + align:start position:0% +I will be to hold that asset because at +the end of the day as a as an investor + + align:start position:0% +the end of the day as a as an investor + + + align:start position:0% +the end of the day as a as an investor +what I care about is not how beautiful + + align:start position:0% +what I care about is not how beautiful + + + align:start position:0% +what I care about is not how beautiful +is the building or anything like that + + align:start position:0% +is the building or anything like that + + + align:start position:0% +is the building or anything like that +what I care is about my chances to get + + align:start position:0% +what I care is about my chances to get + + + align:start position:0% +what I care is about my chances to get +to retrieve back cash flows so as those + + align:start position:0% +to retrieve back cash flows so as those + + + align:start position:0% +to retrieve back cash flows so as those +cash flows are getting riskier then my + + align:start position:0% +cash flows are getting riskier then my + + + align:start position:0% +cash flows are getting riskier then my +willingness to pay for that asset is + + align:start position:0% +willingness to pay for that asset is + + + align:start position:0% +willingness to pay for that asset is +going to be lower because you know it + + align:start position:0% +going to be lower because you know it + + + align:start position:0% +going to be lower because you know it +might be that the tenants go away if you + + align:start position:0% +might be that the tenants go away if you + + + align:start position:0% +might be that the tenants go away if you +think about holding the same asset + + align:start position:0% +think about holding the same asset + + + align:start position:0% +think about holding the same asset +before and after covid or before and + + align:start position:0% +before and after covid or before and + + + align:start position:0% +before and after covid or before and +after the war work from home uh changes + + align:start position:0% +after the war work from home uh changes + + + align:start position:0% +after the war work from home uh changes +in New York it is probably the same + + align:start position:0% +in New York it is probably the same + + + align:start position:0% +in New York it is probably the same +Leist structure and so for in a lot of + + align:start position:0% +Leist structure and so for in a lot of + + + align:start position:0% +Leist structure and so for in a lot of +assets but now I'm way more worried that + + align:start position:0% +assets but now I'm way more worried that + + + align:start position:0% +assets but now I'm way more worried that +those tenants will leave and even though + + align:start position:0% +those tenants will leave and even though + + + align:start position:0% +those tenants will leave and even though +I'm buying the same set of contracts my + + align:start position:0% +I'm buying the same set of contracts my + + + align:start position:0% +I'm buying the same set of contracts my +expectation that those leases will stop + + align:start position:0% +expectation that those leases will stop + + + align:start position:0% +expectation that those leases will stop +is much higher so for whatever the + + align:start position:0% +is much higher so for whatever the + + + align:start position:0% +is much higher so for whatever the +rental value is as of now I'm going to + + align:start position:0% +rental value is as of now I'm going to + + + align:start position:0% +rental value is as of now I'm going to +pay much lower price because i'm way + + align:start position:0% +pay much lower price because i'm way + + + align:start position:0% +pay much lower price because i'm way +more + + align:start position:0% +more + + + align:start position:0% +more +worried okay who can help me with the + + align:start position:0% +worried okay who can help me with the + + + align:start position:0% +worried okay who can help me with the +top with the bottom + + align:start position:0% + + + + align:start position:0% + +bill as prices increase for + + align:start position:0% +bill as prices increase for + + + align:start position:0% +bill as prices increase for +assets developers resp build more MH + + align:start position:0% +assets developers resp build more MH + + + align:start position:0% +assets developers resp build more MH +okay and uh what about this why is not + + align:start position:0% +okay and uh what about this why is not + + + align:start position:0% +okay and uh what about this why is not +like the rest of the lines start + + align:start position:0% +like the rest of the lines start + + + align:start position:0% +like the rest of the lines start +here in the in the cross of the two axis + + align:start position:0% +here in the in the cross of the two axis + + + align:start position:0% +here in the in the cross of the two axis +why is that one started only here um I'm + + align:start position:0% +why is that one started only here um I'm + + + align:start position:0% +why is that one started only here um I'm +assuming because you already have a + + align:start position:0% +assuming because you already have a + + + align:start position:0% +assuming because you already have a +certain amount of MH you're not going to + + align:start position:0% +certain amount of MH you're not going to + + + align:start position:0% +certain amount of MH you're not going to +go to zero like you're going to always + + align:start position:0% +go to zero like you're going to always + + + align:start position:0% +go to zero like you're going to always +have some square footage some stock and + + align:start position:0% +have some square footage some stock and + + + align:start position:0% +have some square footage some stock and +that's why it doesn't start from + + align:start position:0% +that's why it doesn't start from + + + align:start position:0% +that's why it doesn't start from +zero any other + + align:start position:0% + + + + align:start position:0% + +thought make any money so certain price + + align:start position:0% +thought make any money so certain price + + + align:start position:0% +thought make any money so certain price +it started to make and that's where it + + align:start position:0% +it started to make and that's where it + + + align:start position:0% +it started to make and that's where it +yeah so you can think about this as the + + align:start position:0% +yeah so you can think about this as the + + + align:start position:0% +yeah so you can think about this as the +number of square feet that are built if + + align:start position:0% +number of square feet that are built if + + + align:start position:0% +number of square feet that are built if +you don't reach certain amount you will + + align:start position:0% +you don't reach certain amount you will + + + align:start position:0% +you don't reach certain amount you will +be at all you will not have make any + + align:start position:0% +be at all you will not have make any + + + align:start position:0% +be at all you will not have make any +sense of building a building at all uh + + align:start position:0% +sense of building a building at all uh + + + align:start position:0% +sense of building a building at all uh +what makes this curve + + align:start position:0% + + + + align:start position:0% + +move here we have like preferences of + + align:start position:0% +move here we have like preferences of + + + align:start position:0% +move here we have like preferences of +tenants here we have the cap rates and + + align:start position:0% +tenants here we have the cap rates and + + + align:start position:0% +tenants here we have the cap rates and +the assessment of risk of an asset what + + align:start position:0% +the assessment of risk of an asset what + + + align:start position:0% +the assessment of risk of an asset what +do we have + + align:start position:0% +do we have + + + align:start position:0% +do we have +here Julio construction prices and + + align:start position:0% +here Julio construction prices and + + + align:start position:0% +here Julio construction prices and +construction cost yeah yeah and + + align:start position:0% +construction cost yeah yeah and + + + align:start position:0% +construction cost yeah yeah and +something + + align:start position:0% +something + + + align:start position:0% +something +else it doesn't change a lot let's say + + align:start position:0% +else it doesn't change a lot let's say + + + align:start position:0% +else it doesn't change a lot let's say +permitting and yeah so those are costs + + align:start position:0% +permitting and yeah so those are costs + + + align:start position:0% +permitting and yeah so those are costs +of building that that asset uh material + + align:start position:0% +of building that that asset uh material + + + align:start position:0% +of building that that asset uh material +cost and other things so Carlos you were + + align:start position:0% +cost and other things so Carlos you were + + + align:start position:0% +cost and other things so Carlos you were +saying maybe we shouldn't let people + + align:start position:0% +saying maybe we shouldn't let people + + + align:start position:0% +saying maybe we shouldn't let people +live in areas that are going to be hit + + align:start position:0% +live in areas that are going to be hit + + + align:start position:0% +live in areas that are going to be hit +by certain disasters if we make those + + align:start position:0% +by certain disasters if we make those + + + align:start position:0% +by certain disasters if we make those +things more difficult if we make the + + align:start position:0% +things more difficult if we make the + + + align:start position:0% +things more difficult if we make the +requirements the resiliency uh + + align:start position:0% +requirements the resiliency uh + + + align:start position:0% +requirements the resiliency uh +requirements for assets to be higher it + + align:start position:0% +requirements for assets to be higher it + + + align:start position:0% +requirements for assets to be higher it +is great on the one on the hand that the + + align:start position:0% +is great on the one on the hand that the + + + align:start position:0% +is great on the one on the hand that the +the assets that are going to be built + + align:start position:0% +the assets that are going to be built + + + align:start position:0% +the assets that are going to be built +are going to be safer but on the other + + align:start position:0% +are going to be safer but on the other + + + align:start position:0% +are going to be safer but on the other +hand there will be some assets that will + + align:start position:0% +hand there will be some assets that will + + + align:start position:0% +hand there will be some assets that will +not be built because are the the cost of + + align:start position:0% +not be built because are the the cost of + + + align:start position:0% +not be built because are the the cost of +construction are going up so then you + + align:start position:0% +construction are going up so then you + + + align:start position:0% +construction are going up so then you +need prices to be high up higher up to + + align:start position:0% +need prices to be high up higher up to + + + align:start position:0% +need prices to be high up higher up to +make sure that you compensate for the + + align:start position:0% +make sure that you compensate for the + + + align:start position:0% +make sure that you compensate for the +increase requirements in in uh in + + align:start position:0% +increase requirements in in uh in + + + align:start position:0% +increase requirements in in uh in +building uh certain buildings uh and + + align:start position:0% +building uh certain buildings uh and + + + align:start position:0% +building uh certain buildings uh and +what about the last one this one relates + + align:start position:0% +what about the last one this one relates + + + align:start position:0% +what about the last one this one relates +the amount of buildings that are + + align:start position:0% +the amount of buildings that are + + + align:start position:0% +the amount of buildings that are +constructed with the amount of buildings + + align:start position:0% +constructed with the amount of buildings + + + align:start position:0% +constructed with the amount of buildings +that are EST stand in in the uh in the + + align:start position:0% +that are EST stand in in the uh in the + + + align:start position:0% +that are EST stand in in the uh in the +market and um in the market there's the + + align:start position:0% +market and um in the market there's the + + + align:start position:0% +market and um in the market there's the +existing assets and there's a + + align:start position:0% +existing assets and there's a + + + align:start position:0% +existing assets and there's a +depreciation of the existing stock and + + align:start position:0% +depreciation of the existing stock and + + + align:start position:0% +depreciation of the existing stock and +the new amount of construction that + + align:start position:0% +the new amount of construction that + + + align:start position:0% +the new amount of construction that +comes in from the third quadrant will + + align:start position:0% +comes in from the third quadrant will + + + align:start position:0% +comes in from the third quadrant will +increase that value but if construction + + align:start position:0% +increase that value but if construction + + + align:start position:0% +increase that value but if construction +slows down you already have the existing + + align:start position:0% +slows down you already have the existing + + + align:start position:0% +slows down you already have the existing +stock but that's decreasing at the + + align:start position:0% +stock but that's decreasing at the + + + align:start position:0% +stock but that's decreasing at the +appreciation + + align:start position:0% +appreciation + + + align:start position:0% +appreciation +rate so new stock feeds that higher and + + align:start position:0% +rate so new stock feeds that higher and + + + align:start position:0% +rate so new stock feeds that higher and +then a stall in construction means that + + align:start position:0% +then a stall in construction means that + + + align:start position:0% +then a stall in construction means that +the number comes down great what can + + align:start position:0% +the number comes down great what can + + + align:start position:0% +the number comes down great what can +move that curve the depreciation + + align:start position:0% + + + + align:start position:0% + +M yeah so if um if things like for + + align:start position:0% +M yeah so if um if things like for + + + align:start position:0% +M yeah so if um if things like for +example the amount of uh how harsh is + + align:start position:0% +example the amount of uh how harsh is + + + align:start position:0% +example the amount of uh how harsh is +the place in terms of the depreciation + + align:start position:0% +the place in terms of the depreciation + + + align:start position:0% +the place in terms of the depreciation +of that assets or maybe even when it + + align:start position:0% +of that assets or maybe even when it + + + align:start position:0% +of that assets or maybe even when it +comes to equipment the requirements for + + align:start position:0% +comes to equipment the requirements for + + + align:start position:0% +comes to equipment the requirements for +that equipment to be full power all the + + align:start position:0% +that equipment to be full power all the + + + align:start position:0% +that equipment to be full power all the +time in terms of temperature and so + + align:start position:0% +time in terms of temperature and so + + + align:start position:0% +time in terms of temperature and so +forth then the amount of depreciation + + align:start position:0% +forth then the amount of depreciation + + + align:start position:0% +forth then the amount of depreciation +will be higher but also if you have the + + align:start position:0% +will be higher but also if you have the + + + align:start position:0% +will be higher but also if you have the +risk of these assets to be banish every + + align:start position:0% +risk of these assets to be banish every + + + align:start position:0% +risk of these assets to be banish every +other decade then you also have somehow + + align:start position:0% +other decade then you also have somehow + + + align:start position:0% +other decade then you also have somehow +there a probability that whatever you're + + align:start position:0% +there a probability that whatever you're + + + align:start position:0% +there a probability that whatever you're +are building is going to be destroyed at + + align:start position:0% +are building is going to be destroyed at + + + align:start position:0% +are building is going to be destroyed at +some point and the stock is not going to + + align:start position:0% +some point and the stock is not going to + + + align:start position:0% +some point and the stock is not going to +translate one1 to uh to the construction + + align:start position:0% +translate one1 to uh to the construction + + + align:start position:0% +translate one1 to uh to the construction +okay so we are going to use those things + + align:start position:0% +okay so we are going to use those things + + + align:start position:0% +okay so we are going to use those things +and and the important thing is that + + align:start position:0% +and and the important thing is that + + + align:start position:0% +and and the important thing is that +everything is ultimately connected so if + + align:start position:0% +everything is ultimately connected so if + + + align:start position:0% +everything is ultimately connected so if +something is happening to to our tenants + + align:start position:0% +something is happening to to our tenants + + + align:start position:0% +something is happening to to our tenants +it's going to shift this curve and it's + + align:start position:0% +it's going to shift this curve and it's + + + align:start position:0% +it's going to shift this curve and it's +going to ultimately shift the prices of + + align:start position:0% +going to ultimately shift the prices of + + + align:start position:0% +going to ultimately shift the prices of +of uh of Assets in the market and it's + + align:start position:0% +of uh of Assets in the market and it's + + + align:start position:0% +of uh of Assets in the market and it's +going to shift the construction rate and + + align:start position:0% +going to shift the construction rate and + + + align:start position:0% +going to shift the construction rate and +it's going to shift ultimately the + + align:start position:0% +it's going to shift ultimately the + + + align:start position:0% +it's going to shift ultimately the +supply of assets in in the market so + + align:start position:0% +supply of assets in in the market so + + + align:start position:0% +supply of assets in in the market so +everything is connected so whenever we + + align:start position:0% +everything is connected so whenever we + + + align:start position:0% +everything is connected so whenever we +have a report wherever we have a study + + align:start position:0% +have a report wherever we have a study + + + align:start position:0% +have a report wherever we have a study +that will tell us that this quadrant is + + align:start position:0% +that will tell us that this quadrant is + + + align:start position:0% +that will tell us that this quadrant is +affected or that quadrant is affected + + align:start position:0% +affected or that quadrant is affected + + + align:start position:0% +affected or that quadrant is affected +ultimately the whole market and everyone + + align:start position:0% +ultimately the whole market and everyone + + + align:start position:0% +ultimately the whole market and everyone +in that market is affected and and the + + align:start position:0% +in that market is affected and and the + + + align:start position:0% +in that market is affected and and the +key is that if we don't have that view + + align:start position:0% +key is that if we don't have that view + + + align:start position:0% +key is that if we don't have that view +we will have a very myopic view of the + + align:start position:0% +we will have a very myopic view of the + + + align:start position:0% +we will have a very myopic view of the +of the whole climate change because we + + align:start position:0% +of the whole climate change because we + + + align:start position:0% +of the whole climate change because we +will only think about this partial view + + align:start position:0% +will only think about this partial view + + + align:start position:0% +will only think about this partial view +of okay yeah rains will change but yeah + + align:start position:0% +of okay yeah rains will change but yeah + + + align:start position:0% +of okay yeah rains will change but yeah +if rain changes then the investors will + + align:start position:0% +if rain changes then the investors will + + + align:start position:0% +if rain changes then the investors will +will act differently and then the + + align:start position:0% +will act differently and then the + + + align:start position:0% +will act differently and then the +contractor construction companies will + + align:start position:0% +contractor construction companies will + + + align:start position:0% +contractor construction companies will +act differently and ultimately the + + align:start position:0% +act differently and ultimately the + + + align:start position:0% +act differently and ultimately the +supply will be different so all of these + + align:start position:0% +supply will be different so all of these + + + align:start position:0% +supply will be different so all of these +long-term short-term effects is + + align:start position:0% +long-term short-term effects is + + + align:start position:0% +long-term short-term effects is +something that we have to be very + + align:start position:0% +something that we have to be very + + + align:start position:0% +something that we have to be very +present uh when we are analyzing the + + align:start position:0% +present uh when we are analyzing the + + + align:start position:0% +present uh when we are analyzing the +consequences of climate change in the + + align:start position:0% +consequences of climate change in the + + + align:start position:0% +consequences of climate change in the +real estate industry and that's where + + align:start position:0% +real estate industry and that's where + + + align:start position:0% +real estate industry and that's where +one of the the key values of knowing + + align:start position:0% +one of the the key values of knowing + + + align:start position:0% +one of the the key values of knowing +real estate economics when we are + + align:start position:0% +real estate economics when we are + + + align:start position:0% +real estate economics when we are +thinking about this and that's the value + + align:start position:0% +thinking about this and that's the value + + + align:start position:0% +thinking about this and that's the value +for those that are doing the mid program + + align:start position:0% +for those that are doing the mid program + + + align:start position:0% +for those that are doing the mid program +to come from that course all the way + + align:start position:0% +to come from that course all the way + + + align:start position:0% +to come from that course all the way +into here so if you think about the + + align:start position:0% +into here so if you think about the + + + align:start position:0% +into here so if you think about the +demand side Leah I just have a quick + + align:start position:0% +demand side Leah I just have a quick + + + align:start position:0% +demand side Leah I just have a quick +question sure + + align:start position:0% +question sure + + + align:start position:0% +question sure +this is for the Ral Market how does it + + align:start position:0% +this is for the Ral Market how does it + + + align:start position:0% +this is for the Ral Market how does it +work for own yeah so here we are + + align:start position:0% +work for own yeah so here we are + + + align:start position:0% +work for own yeah so here we are +thinking about uh commercial real estate + + align:start position:0% +thinking about uh commercial real estate + + + align:start position:0% +thinking about uh commercial real estate +properties in in uh this Center we have + + align:start position:0% +properties in in uh this Center we have + + + align:start position:0% +properties in in uh this Center we have +uh thanks to David gner that kind of + + align:start position:0% +uh thanks to David gner that kind of + + + align:start position:0% +uh thanks to David gner that kind of +brainwash us we think about commercial + + align:start position:0% +brainwash us we think about commercial + + + align:start position:0% +brainwash us we think about commercial +real estate as any income generating + + align:start position:0% +real estate as any income generating + + + align:start position:0% +real estate as any income generating +property so you can think also here as + + align:start position:0% +property so you can think also here as + + + align:start position:0% +property so you can think also here as +res as a multif family and kind of if + + align:start position:0% +res as a multif family and kind of if + + + align:start position:0% +res as a multif family and kind of if +you will rent a an apartment it will be + + align:start position:0% +you will rent a an apartment it will be + + + align:start position:0% +you will rent a an apartment it will be +part of this uh if you think about home + + align:start position:0% +part of this uh if you think about home + + + align:start position:0% +part of this uh if you think about home +ownership that will be basically you + + align:start position:0% +ownership that will be basically you + + + align:start position:0% +ownership that will be basically you +will not have this but you will have + + align:start position:0% +will not have this but you will have + + + align:start position:0% +will not have this but you will have +some sort of utility of living in that + + align:start position:0% +some sort of utility of living in that + + + align:start position:0% +some sort of utility of living in that +place so you will have a monetization in + + align:start position:0% +place so you will have a monetization in + + + align:start position:0% +place so you will have a monetization in +your head of what it is what it meant + + align:start position:0% +your head of what it is what it meant + + + align:start position:0% +your head of what it is what it meant +means for you to live in that place we + + align:start position:0% +means for you to live in that place we + + + align:start position:0% +means for you to live in that place we +will see some graph now also in in the + + align:start position:0% +will see some graph now also in in the + + + align:start position:0% +will see some graph now also in in the +uh from the empirical studies on how + + align:start position:0% +uh from the empirical studies on how + + + align:start position:0% +uh from the empirical studies on how +home owners and and home buyers are + + align:start position:0% +home owners and and home buyers are + + + align:start position:0% +home owners and and home buyers are +actually changing uh their willingness + + align:start position:0% +actually changing uh their willingness + + + align:start position:0% +actually changing uh their willingness +to pay to live in a certain place + + align:start position:0% +to pay to live in a certain place + + + align:start position:0% +to pay to live in a certain place +depending on the temperature of those + + align:start position:0% +depending on the temperature of those + + + align:start position:0% +depending on the temperature of those +places so there will be some that's how + + align:start position:0% +places so there will be some that's how + + + align:start position:0% +places so there will be some that's how +we use it in economics we will translate + + align:start position:0% +we use it in economics we will translate + + + align:start position:0% +we use it in economics we will translate +your happiness or utility to live in a + + align:start position:0% +your happiness or utility to live in a + + + align:start position:0% +your happiness or utility to live in a +place into willingness to pay or any + + align:start position:0% +place into willingness to pay or any + + + align:start position:0% +place into willingness to pay or any +kind of monetary value that will + + align:start position:0% +kind of monetary value that will + + + align:start position:0% +kind of monetary value that will +translate that into some sort of demand + + align:start position:0% +translate that into some sort of demand + + + align:start position:0% +translate that into some sort of demand +curve okay and then there will be some + + align:start position:0% +curve okay and then there will be some + + + align:start position:0% +curve okay and then there will be some +investors that it is on the one hand + + align:start position:0% +investors that it is on the one hand + + + align:start position:0% +investors that it is on the one hand +that Equity investor so someone that is + + align:start position:0% +that Equity investor so someone that is + + + align:start position:0% +that Equity investor so someone that is +buying or co- buying that property with + + align:start position:0% +buying or co- buying that property with + + + align:start position:0% +buying or co- buying that property with +you but it's also here that is someone + + align:start position:0% +you but it's also here that is someone + + + align:start position:0% +you but it's also here that is someone +important here that are the banks and + + align:start position:0% +important here that are the banks and + + + align:start position:0% +important here that are the banks and +the and the Deb providers so they are + + align:start position:0% +the and the Deb providers so they are + + + align:start position:0% +the and the Deb providers so they are +going to be here even if you're a + + align:start position:0% +going to be here even if you're a + + + align:start position:0% +going to be here even if you're a +homeowner and that will be applying a + + align:start position:0% +homeowner and that will be applying a + + + align:start position:0% +homeowner and that will be applying a +lot of the logic to to that for Quadrant + + align:start position:0% +lot of the logic to to that for Quadrant + + + align:start position:0% +lot of the logic to to that for Quadrant +model tooo + + align:start position:0% +model tooo + + + align:start position:0% +model tooo +okay um so what do we what can we expect + + align:start position:0% +okay um so what do we what can we expect + + + align:start position:0% +okay um so what do we what can we expect +in terms of climate change impacts on + + align:start position:0% +in terms of climate change impacts on + + + align:start position:0% +in terms of climate change impacts on +the space Market what do we think do we + + align:start position:0% +the space Market what do we think do we + + + align:start position:0% +the space Market what do we think do we +think that people are going to be more + + align:start position:0% +think that people are going to be more + + + align:start position:0% +think that people are going to be more +happy to live in places that are going + + align:start position:0% +happy to live in places that are going + + + align:start position:0% +happy to live in places that are going +to be at risk of wildfires so let's + + align:start position:0% +to be at risk of wildfires so let's + + + align:start position:0% +to be at risk of wildfires so let's +think about California or are we going + + align:start position:0% +think about California or are we going + + + align:start position:0% +think about California or are we going +to think that people are less happy to + + align:start position:0% +to think that people are less happy to + + + align:start position:0% +to think that people are less happy to +live there and how are we going to see + + align:start position:0% +live there and how are we going to see + + + align:start position:0% +live there and how are we going to see +that in the + + align:start position:0% +that in the + + + align:start position:0% +that in the +market um some + + align:start position:0% + + + + align:start position:0% + +yeah + + align:start position:0% + + + + align:start position:0% + +yeah yeah and that will have a direct + + align:start position:0% +yeah yeah and that will have a direct + + + align:start position:0% +yeah yeah and that will have a direct +impact on the rents But ultimately + + align:start position:0% +impact on the rents But ultimately + + + align:start position:0% +impact on the rents But ultimately +because the rents now are lower in that + + align:start position:0% +because the rents now are lower in that + + + align:start position:0% +because the rents now are lower in that +market prices and ultimately the + + align:start position:0% +market prices and ultimately the + + + align:start position:0% +market prices and ultimately the +construction activity so that's how that + + align:start position:0% +construction activity so that's how that + + + align:start position:0% +construction activity so that's how that +uh that shifts the whole whole idea so + + align:start position:0% +uh that shifts the whole whole idea so + + + align:start position:0% +uh that shifts the whole whole idea so +and that if we want to put it into what + + align:start position:0% +and that if we want to put it into what + + + align:start position:0% +and that if we want to put it into what +will determine that it will be the the + + align:start position:0% +will determine that it will be the the + + + align:start position:0% +will determine that it will be the the +attractiveness of that space so if you + + align:start position:0% +attractiveness of that space so if you + + + align:start position:0% +attractiveness of that space so if you +are exposed not only to to couple of + + align:start position:0% +are exposed not only to to couple of + + + align:start position:0% +are exposed not only to to couple of +days of heat waves a year but actually + + align:start position:0% +days of heat waves a year but actually + + + align:start position:0% +days of heat waves a year but actually +now it starts to be like two weeks three + + align:start position:0% +now it starts to be like two weeks three + + + align:start position:0% +now it starts to be like two weeks three +weeks a year of heat waves then as a + + align:start position:0% +weeks a year of heat waves then as a + + + align:start position:0% +weeks a year of heat waves then as a +resident of that place you're going to + + align:start position:0% +resident of that place you're going to + + + align:start position:0% +resident of that place you're going to +be uh less keen on living in that in + + align:start position:0% +be uh less keen on living in that in + + + align:start position:0% +be uh less keen on living in that in +that place yeah H that could also work + + align:start position:0% +that place yeah H that could also work + + + align:start position:0% +that place yeah H that could also work +the other way around right when you have + + align:start position:0% +the other way around right when you have + + + align:start position:0% +the other way around right when you have +people moving from one place to the + + align:start position:0% +people moving from one place to the + + + align:start position:0% +people moving from one place to the +other because climate change correct + + align:start position:0% +other because climate change correct + + + align:start position:0% +other because climate change correct +have effect correct here we are thinking + + align:start position:0% +have effect correct here we are thinking + + + align:start position:0% +have effect correct here we are thinking +about areas that are uh badly impacted + + align:start position:0% +about areas that are uh badly impacted + + + align:start position:0% +about areas that are uh badly impacted +by that so more heat + + align:start position:0% +by that so more heat + + + align:start position:0% +by that so more heat +waves cities like New York City like + + align:start position:0% +waves cities like New York City like + + + align:start position:0% +waves cities like New York City like +Boston that are experiencing more and + + align:start position:0% +Boston that are experiencing more and + + + align:start position:0% +Boston that are experiencing more and +more heat waves uh and so forth uh also + + align:start position:0% +more heat waves uh and so forth uh also + + + align:start position:0% +more heat waves uh and so forth uh also +impacts of occupants so these are for + + align:start position:0% +impacts of occupants so these are for + + + align:start position:0% +impacts of occupants so these are for +people that want to live there but + + align:start position:0% +people that want to live there but + + + align:start position:0% +people that want to live there but +companies that are renting a space to + + align:start position:0% +companies that are renting a space to + + + align:start position:0% +companies that are renting a space to +work there they will be worried about + + align:start position:0% +work there they will be worried about + + + align:start position:0% +work there they will be worried about +performance changes they will be worried + + align:start position:0% +performance changes they will be worried + + + align:start position:0% +performance changes they will be worried +about Behavior change of consumers so + + align:start position:0% +about Behavior change of consumers so + + + align:start position:0% +about Behavior change of consumers so +people are actually less likely to go to + + align:start position:0% +people are actually less likely to go to + + + align:start position:0% +people are actually less likely to go to +the shopping mall because it's in uh uh + + align:start position:0% +the shopping mall because it's in uh uh + + + align:start position:0% +the shopping mall because it's in uh uh +attactive for more severe storms for + + align:start position:0% +attactive for more severe storms for + + + align:start position:0% +attactive for more severe storms for +more heat waves and so so forth they are + + align:start position:0% +more heat waves and so so forth they are + + + align:start position:0% +more heat waves and so so forth they are +all going to beat lower in their leasing + + align:start position:0% +all going to beat lower in their leasing + + + align:start position:0% +all going to beat lower in their leasing +uh beats than they used to be and then + + align:start position:0% +uh beats than they used to be and then + + + align:start position:0% +uh beats than they used to be and then +also ultimately the impact of on on + + align:start position:0% +also ultimately the impact of on on + + + align:start position:0% +also ultimately the impact of on on +amenities and also the climate risk + + align:start position:0% +amenities and also the climate risk + + + align:start position:0% +amenities and also the climate risk +discloser uh this is what you see so + + align:start position:0% +discloser uh this is what you see so + + + align:start position:0% +discloser uh this is what you see so +here this is translated into this model + + align:start position:0% +here this is translated into this model + + + align:start position:0% +here this is translated into this model +of uh R robot model where you say well + + align:start position:0% +of uh R robot model where you say well + + + align:start position:0% +of uh R robot model where you say well +the amount of money that you're going to + + align:start position:0% +the amount of money that you're going to + + + align:start position:0% +the amount of money that you're going to +to pay for living a place of rent is + + align:start position:0% +to pay for living a place of rent is + + + align:start position:0% +to pay for living a place of rent is +going to be affected by the amount of + + align:start position:0% +going to be affected by the amount of + + + align:start position:0% +going to be affected by the amount of +money that you earn as a uh in the labor + + align:start position:0% +money that you earn as a uh in the labor + + + align:start position:0% +money that you earn as a uh in the labor +market and also your appreciation for + + align:start position:0% +market and also your appreciation for + + + align:start position:0% +market and also your appreciation for +that place so you can actually uh be + + align:start position:0% +that place so you can actually uh be + + + align:start position:0% +that place so you can actually uh be +willing to earn less if you are in a + + align:start position:0% +willing to earn less if you are in a + + + align:start position:0% +willing to earn less if you are in a +place that really gives you a lot of + + align:start position:0% +place that really gives you a lot of + + + align:start position:0% +place that really gives you a lot of +utility a lot of nice place so you know + + align:start position:0% +utility a lot of nice place so you know + + + align:start position:0% +utility a lot of nice place so you know +if you are living in a very uh bad place + + align:start position:0% +if you are living in a very uh bad place + + + align:start position:0% +if you are living in a very uh bad place +like think about a very bad with low + + align:start position:0% +like think about a very bad with low + + + align:start position:0% +like think about a very bad with low +amenities industrial area in the middle + + align:start position:0% +amenities industrial area in the middle + + + align:start position:0% +amenities industrial area in the middle +of nowhere they really need to pay you a + + align:start position:0% +of nowhere they really need to pay you a + + + align:start position:0% +of nowhere they really need to pay you a +lot to attract someone as talented as + + align:start position:0% +lot to attract someone as talented as + + + align:start position:0% +lot to attract someone as talented as +you guys to be on working there but if + + align:start position:0% +you guys to be on working there but if + + + align:start position:0% +you guys to be on working there but if +someone has a little bit lower payche + + align:start position:0% +someone has a little bit lower payche + + + align:start position:0% +someone has a little bit lower payche +but is in an area next to a nice Lake + + align:start position:0% +but is in an area next to a nice Lake + + + align:start position:0% +but is in an area next to a nice Lake +mountains whatever you are going to be + + align:start position:0% +mountains whatever you are going to be + + + align:start position:0% +mountains whatever you are going to be +less uh less greedy when it comes to + + align:start position:0% +less uh less greedy when it comes to + + + align:start position:0% +less uh less greedy when it comes to +negotiating those terms because you + + align:start position:0% +negotiating those terms because you + + + align:start position:0% +negotiating those terms because you +really want to live there or if you have + + align:start position:0% +really want to live there or if you have + + + align:start position:0% +really want to live there or if you have +the family next to you or whatever you + + align:start position:0% +the family next to you or whatever you + + + align:start position:0% +the family next to you or whatever you +want to gives you a quality of life so + + align:start position:0% +want to gives you a quality of life so + + + align:start position:0% +want to gives you a quality of life so +as the quality of life reduces the + + align:start position:0% +as the quality of life reduces the + + + align:start position:0% +as the quality of life reduces the +people will have the companies will have + + align:start position:0% +people will have the companies will have + + + align:start position:0% +people will have the companies will have +to pay you more or you have or the + + align:start position:0% +to pay you more or you have or the + + + align:start position:0% +to pay you more or you have or the +landlords will have to ask you less rent + + align:start position:0% +landlords will have to ask you less rent + + + align:start position:0% +landlords will have to ask you less rent +because you are less attractive to live + + align:start position:0% +because you are less attractive to live + + + align:start position:0% +because you are less attractive to live +in that area so as climate change is + + align:start position:0% +in that area so as climate change is + + + align:start position:0% +in that area so as climate change is +actually uh or temperature if for + + align:start position:0% +actually uh or temperature if for + + + align:start position:0% +actually uh or temperature if for +example temperature exposure will + + align:start position:0% +example temperature exposure will + + + align:start position:0% +example temperature exposure will +actually reduce that quality of life + + align:start position:0% +actually reduce that quality of life + + + align:start position:0% +actually reduce that quality of life +that will mean that either you are + + align:start position:0% +that will mean that either you are + + + align:start position:0% +that will mean that either you are +required to pay less to be in that place + + align:start position:0% +required to pay less to be in that place + + + align:start position:0% +required to pay less to be in that place +or the employers will have to pay you + + align:start position:0% +or the employers will have to pay you + + + align:start position:0% +or the employers will have to pay you +more but basically the rent the real + + align:start position:0% +more but basically the rent the real + + + align:start position:0% +more but basically the rent the real +rents will actually need to go down yeah + + align:start position:0% + + + + align:start position:0% + +sure people comp to + + align:start position:0% +sure people comp to + + + align:start position:0% +sure people comp to +Adreas construction yeah that is also + + align:start position:0% +Adreas construction yeah that is also + + + align:start position:0% +Adreas construction yeah that is also +something that will be there so that + + align:start position:0% +something that will be there so that + + + align:start position:0% +something that will be there so that +will be the other quadrant this is more + + align:start position:0% +will be the other quadrant this is more + + + align:start position:0% +will be the other quadrant this is more +for the uh for the demand the demand for + + align:start position:0% +for the uh for the demand the demand for + + + align:start position:0% +for the uh for the demand the demand for +a space so there is not the adaptation + + align:start position:0% +a space so there is not the adaptation + + + align:start position:0% +a space so there is not the adaptation +but it's more like kind of there is a + + align:start position:0% +but it's more like kind of there is a + + + align:start position:0% +but it's more like kind of there is a +set of buildings that are built for you + + align:start position:0% +set of buildings that are built for you + + + align:start position:0% +set of buildings that are built for you +and where do you choose to leave and how + + align:start position:0% +and where do you choose to leave and how + + + align:start position:0% +and where do you choose to leave and how +much are you choosing to pay for those + + align:start position:0% +much are you choosing to pay for those + + + align:start position:0% +much are you choosing to pay for those +buildings and then there will be the + + align:start position:0% +buildings and then there will be the + + + align:start position:0% +buildings and then there will be the +construction company that is trying to + + align:start position:0% +construction company that is trying to + + + align:start position:0% +construction company that is trying to +to match those preferences to the + + align:start position:0% +to match those preferences to the + + + align:start position:0% +to match those preferences to the +characteristics of those of those places + + align:start position:0% +characteristics of those of those places + + + align:start position:0% +characteristics of those of those places +and indeed if now you required to live + + align:start position:0% +and indeed if now you required to live + + + align:start position:0% +and indeed if now you required to live +in a place or to work in a place that + + align:start position:0% +in a place or to work in a place that + + + align:start position:0% +in a place or to work in a place that +are that are that needs an + + align:start position:0% +are that are that needs an + + + align:start position:0% +are that are that needs an +infrastructure upgrade because now you + + align:start position:0% +infrastructure upgrade because now you + + + align:start position:0% +infrastructure upgrade because now you +need to have a fancier easy unit you + + align:start position:0% +need to have a fancier easy unit you + + + align:start position:0% +need to have a fancier easy unit you +need to have a a a stronger seaw wall + + align:start position:0% +need to have a a a stronger seaw wall + + + align:start position:0% +need to have a a a stronger seaw wall +around the property then that will + + align:start position:0% +around the property then that will + + + align:start position:0% +around the property then that will +increase the construction cost and that + + align:start position:0% +increase the construction cost and that + + + align:start position:0% +increase the construction cost and that +will have H an ultimate effect on the + + align:start position:0% +will have H an ultimate effect on the + + + align:start position:0% +will have H an ultimate effect on the +supply and the cost and the and the + + align:start position:0% +supply and the cost and the and the + + + align:start position:0% +supply and the cost and the and the +price for those + + align:start position:0% +price for those + + + align:start position:0% +price for those +properties and this is what you see in + + align:start position:0% +properties and this is what you see in + + + align:start position:0% +properties and this is what you see in +the empirical data so you see that + + align:start position:0% +the empirical data so you see that + + + align:start position:0% +the empirical data so you see that +people actually this is the the amount + + align:start position:0% +people actually this is the the amount + + + align:start position:0% +people actually this is the the amount +of money that people are willing to pay + + align:start position:0% +of money that people are willing to pay + + + align:start position:0% +of money that people are willing to pay +per square feet and this is the winter + + align:start position:0% +per square feet and this is the winter + + + align:start position:0% +per square feet and this is the winter +temperature in fahrenheit so you see + + align:start position:0% +temperature in fahrenheit so you see + + + align:start position:0% +temperature in fahrenheit so you see +that people want to live in places + + align:start position:0% +that people want to live in places + + + align:start position:0% +that people want to live in places +that are + + align:start position:0% +that are + + + align:start position:0% +that are +um warmer in winter and also cooler in + + align:start position:0% +um warmer in winter and also cooler in + + + align:start position:0% +um warmer in winter and also cooler in +in summer for any any region in the in + + align:start position:0% +in summer for any any region in the in + + + align:start position:0% +in summer for any any region in the in +the United States and these are the + + align:start position:0% +the United States and these are the + + + align:start position:0% +the United States and these are the +effects of on behavior and so forth what + + align:start position:0% +effects of on behavior and so forth what + + + align:start position:0% +effects of on behavior and so forth what +about the asset + + align:start position:0% +about the asset + + + align:start position:0% +about the asset +Market what happens there what do we + + align:start position:0% +Market what happens there what do we + + + align:start position:0% +Market what happens there what do we +think about climate risk is there any + + align:start position:0% +think about climate risk is there any + + + align:start position:0% +think about climate risk is there any +impact of climate risk on the asset + + align:start position:0% +impact of climate risk on the asset + + + align:start position:0% +impact of climate risk on the asset +Market or + + align:start position:0% +Market or + + + align:start position:0% +Market or +no I keep pressing twice and then I keep + + align:start position:0% +no I keep pressing twice and then I keep + + + align:start position:0% +no I keep pressing twice and then I keep +giveing the answer but but what I like + + align:start position:0% +giveing the answer but but what I like + + + align:start position:0% +giveing the answer but but what I like +is the is the logic not so much + + align:start position:0% + + + + align:start position:0% + +ashleyk + + align:start position:0% + + + + align:start position:0% + +wild yes that is true that is not the + + align:start position:0% +wild yes that is true that is not the + + + align:start position:0% +wild yes that is true that is not the +space Market but is the asset the + + align:start position:0% +space Market but is the asset the + + + align:start position:0% +space Market but is the asset the +construction Market uh because that will + + align:start position:0% +construction Market uh because that will + + + align:start position:0% +construction Market uh because that will +ultimately impact the price of Timber + + align:start position:0% +ultimately impact the price of Timber + + + align:start position:0% +ultimately impact the price of Timber +and that will ultimately impact how much + + align:start position:0% +and that will ultimately impact how much + + + align:start position:0% +and that will ultimately impact how much +it cost to build a a building Andy + + align:start position:0% +it cost to build a a building Andy + + + align:start position:0% +it cost to build a a building Andy +before we were talking about shifts on + + align:start position:0% +before we were talking about shifts on + + + align:start position:0% +before we were talking about shifts on +the curve uh given a current rent level + + align:start position:0% +the curve uh given a current rent level + + + align:start position:0% +the curve uh given a current rent level +if there's perceived higher risk or + + align:start position:0% +if there's perceived higher risk or + + + align:start position:0% +if there's perceived higher risk or +future higher cost to maintaining the + + align:start position:0% +future higher cost to maintaining the + + + align:start position:0% +future higher cost to maintaining the +property yeah the curve's going to shift + + align:start position:0% +property yeah the curve's going to shift + + + align:start position:0% +property yeah the curve's going to shift +in so that at that current rent level + + align:start position:0% +in so that at that current rent level + + + align:start position:0% +in so that at that current rent level +there's a lower price Market can we + + align:start position:0% +there's a lower price Market can we + + + align:start position:0% +there's a lower price Market can we +think on a specific U event that will + + align:start position:0% +think on a specific U event that will + + + align:start position:0% +think on a specific U event that will +make that curve shift yeah or that will + + align:start position:0% +make that curve shift yeah or that will + + + align:start position:0% +make that curve shift yeah or that will +increase the perception of risk um + + align:start position:0% +increase the perception of risk um + + + align:start position:0% +increase the perception of risk um +insurance premiums double or triple in + + align:start position:0% +insurance premiums double or triple in + + + align:start position:0% +insurance premiums double or triple in +theur given Market your operating + + align:start position:0% +theur given Market your operating + + + align:start position:0% +theur given Market your operating +expenses are that much higher corre so + + align:start position:0% +expenses are that much higher corre so + + + align:start position:0% +expenses are that much higher corre so +you're going to pay a lower price to + + align:start position:0% +you're going to pay a lower price to + + + align:start position:0% +you're going to pay a lower price to +adjust for that at of cost correct + + align:start position:0% +adjust for that at of cost correct + + + align:start position:0% +adjust for that at of cost correct +correct so the rents will what you don't + + align:start position:0% +correct so the rents will what you don't + + + align:start position:0% +correct so the rents will what you don't +what you get is not actually the rents + + align:start position:0% +what you get is not actually the rents + + + align:start position:0% +what you get is not actually the rents +what you get is the ultimate profit of + + align:start position:0% +what you get is the ultimate profit of + + + align:start position:0% +what you get is the ultimate profit of +of holding that asset every year as a as + + align:start position:0% +of holding that asset every year as a as + + + align:start position:0% +of holding that asset every year as a as +a as an owner of that asset so that is + + align:start position:0% +a as an owner of that asset so that is + + + align:start position:0% +a as an owner of that asset so that is +one and there will be also so you have + + align:start position:0% +one and there will be also so you have + + + align:start position:0% +one and there will be also so you have +it here and also great aware greater + + align:start position:0% +it here and also great aware greater + + + align:start position:0% +it here and also great aware greater +awareness of investors that will + + align:start position:0% +awareness of investors that will + + + align:start position:0% +awareness of investors that will +actually adjust the the risk Kevin I + + align:start position:0% +actually adjust the the risk Kevin I + + + align:start position:0% +actually adjust the the risk Kevin I +I'll give you the floor in one minute um + + align:start position:0% +I'll give you the floor in one minute um + + + align:start position:0% +I'll give you the floor in one minute um +and these are there are things like the + + align:start position:0% +and these are there are things like the + + + align:start position:0% +and these are there are things like the +the TV SD the the task force for on + + align:start position:0% +the TV SD the the task force for on + + + align:start position:0% +the TV SD the the task force for on +climate related Financial disclosure + + align:start position:0% +climate related Financial disclosure + + + align:start position:0% +climate related Financial disclosure +where major Banks and investors are + + align:start position:0% +where major Banks and investors are + + + align:start position:0% +where major Banks and investors are +actually forcing uh companies to + + align:start position:0% +actually forcing uh companies to + + + align:start position:0% +actually forcing uh companies to +disclose the climate risk associated + + align:start position:0% +disclose the climate risk associated + + + align:start position:0% +disclose the climate risk associated +with their assets so they can actually + + align:start position:0% +with their assets so they can actually + + + align:start position:0% +with their assets so they can actually +price it in in their in their conditions + + align:start position:0% +price it in in their in their conditions + + + align:start position:0% +price it in in their in their conditions +and terms where they are giving depth to + + align:start position:0% +and terms where they are giving depth to + + + align:start position:0% +and terms where they are giving depth to +uh to building owners so all of this + + align:start position:0% +uh to building owners so all of this + + + align:start position:0% +uh to building owners so all of this +will make that for whatever rent tenants + + align:start position:0% +will make that for whatever rent tenants + + + align:start position:0% +will make that for whatever rent tenants +are willing to pay ultimately the price + + align:start position:0% +are willing to pay ultimately the price + + + align:start position:0% +are willing to pay ultimately the price +for those assets are going to be lower + + align:start position:0% +for those assets are going to be lower + + + align:start position:0% +for those assets are going to be lower +that is going to impact the construction + + align:start position:0% +that is going to impact the construction + + + align:start position:0% +that is going to impact the construction +too and it's going to impact the the + + align:start position:0% +too and it's going to impact the the + + + align:start position:0% +too and it's going to impact the the +long-term Supply in the market + + align:start position:0% + + + + align:start position:0% + +and I have it here and that is also + + align:start position:0% +and I have it here and that is also + + + align:start position:0% +and I have it here and that is also +something that if you see and I'll I'll + + align:start position:0% +something that if you see and I'll I'll + + + align:start position:0% +something that if you see and I'll I'll +discuss this next week in in more detail + + align:start position:0% +discuss this next week in in more detail + + + align:start position:0% +discuss this next week in in more detail +but what you see is that actually when + + align:start position:0% +but what you see is that actually when + + + align:start position:0% +but what you see is that actually when +you see the empirical data you see that + + align:start position:0% +you see the empirical data you see that + + + align:start position:0% +you see the empirical data you see that +a lot of the changes in property prices + + align:start position:0% +a lot of the changes in property prices + + + align:start position:0% +a lot of the changes in property prices +are not coming by changes in noi and + + align:start position:0% +are not coming by changes in noi and + + + align:start position:0% +are not coming by changes in noi and +rents but actually coming from increases + + align:start position:0% +rents but actually coming from increases + + + align:start position:0% +rents but actually coming from increases +in C rate is coming from the perception + + align:start position:0% +in C rate is coming from the perception + + + align:start position:0% +in C rate is coming from the perception +of risk of those properties so for any + + align:start position:0% +of risk of those properties so for any + + + align:start position:0% +of risk of those properties so for any +given rent uh that is out there actually + + align:start position:0% +given rent uh that is out there actually + + + align:start position:0% +given rent uh that is out there actually +now uh owners and investors are willing + + align:start position:0% +now uh owners and investors are willing + + + align:start position:0% +now uh owners and investors are willing +to pay less because because they have a + + align:start position:0% +to pay less because because they have a + + + align:start position:0% +to pay less because because they have a +higher perception of risk on those + + align:start position:0% +higher perception of risk on those + + + align:start position:0% +higher perception of risk on those +properties and it makes sense because + + align:start position:0% +properties and it makes sense because + + + align:start position:0% +properties and it makes sense because +those are the ones that have a long-term + + align:start position:0% +those are the ones that have a long-term + + + align:start position:0% +those are the ones that have a long-term +Horizon versus the ones that are making + + align:start position:0% +Horizon versus the ones that are making + + + align:start position:0% +Horizon versus the ones that are making +a leas for two three five years uh time + + align:start position:0% +a leas for two three five years uh time + + + align:start position:0% +a leas for two three five years uh time +and finally the just as a recap finally + + align:start position:0% +and finally the just as a recap finally + + + align:start position:0% +and finally the just as a recap finally +the the construction what you see is + + align:start position:0% +the the construction what you see is + + + align:start position:0% +the the construction what you see is +that as the cost of materials and the + + align:start position:0% +that as the cost of materials and the + + + align:start position:0% +that as the cost of materials and the +different requirements of companies to + + align:start position:0% +different requirements of companies to + + + align:start position:0% +different requirements of companies to +to uh to construct in certain places you + + align:start position:0% +to uh to construct in certain places you + + + align:start position:0% +to uh to construct in certain places you +see that the the amount of uh + + align:start position:0% +see that the the amount of uh + + + align:start position:0% +see that the the amount of uh +construction is going to go down the the + + align:start position:0% +construction is going to go down the the + + + align:start position:0% +construction is going to go down the the +the price is going to also reflect that + + align:start position:0% +the price is going to also reflect that + + + align:start position:0% +the price is going to also reflect that +and the RS are also going to reflect + + align:start position:0% +and the RS are also going to reflect + + + align:start position:0% +and the RS are also going to reflect +those and finally as the the likelihood + + align:start position:0% +those and finally as the the likelihood + + + align:start position:0% +those and finally as the the likelihood +of the stock to be destroyed increases + + align:start position:0% +of the stock to be destroyed increases + + + align:start position:0% +of the stock to be destroyed increases +then for whatever unit of uh whatever + + align:start position:0% +then for whatever unit of uh whatever + + + align:start position:0% +then for whatever unit of uh whatever +amount of construction is happening now + + align:start position:0% +amount of construction is happening now + + + align:start position:0% +amount of construction is happening now +it's going to survive less and that is + + align:start position:0% +it's going to survive less and that is + + + align:start position:0% +it's going to survive less and that is +going to decrease the supply and have + + align:start position:0% +going to decrease the supply and have + + + align:start position:0% +going to decrease the supply and have +all the bad consequences for rents and + + align:start position:0% +all the bad consequences for rents and + + + align:start position:0% +all the bad consequences for rents and +so forth and remember that at the same + + align:start position:0% +so forth and remember that at the same + + + align:start position:0% +so forth and remember that at the same +time that we have the climate crisis we + + align:start position:0% +time that we have the climate crisis we + + + align:start position:0% +time that we have the climate crisis we +have in a lot of places affordability + + align:start position:0% +have in a lot of places affordability + + + align:start position:0% +have in a lot of places affordability +crisis so we really don't want Supply to + + align:start position:0% +crisis so we really don't want Supply to + + + align:start position:0% +crisis so we really don't want Supply to +be even more constrained uh especially + + align:start position:0% +be even more constrained uh especially + + + align:start position:0% +be even more constrained uh especially +when it comes to the to the housing + + align:start position:0% +when it comes to the to the housing + + + align:start position:0% +when it comes to the to the housing +market market so all of these things is + + align:start position:0% +market market so all of these things is + + + align:start position:0% +market market so all of these things is +going to put a lot of stress into + + align:start position:0% +going to put a lot of stress into + + + align:start position:0% +going to put a lot of stress into +markets and it's going to make a lot of + + align:start position:0% +markets and it's going to make a lot of + + + align:start position:0% +markets and it's going to make a lot of +the lives of a lot of people even more + + align:start position:0% +the lives of a lot of people even more + + + align:start position:0% +the lives of a lot of people even more +miserable \ No newline at end of file diff --git a/RrZ8-1w7iok.txt b/RrZ8-1w7iok.txt new file mode 100644 index 0000000000000000000000000000000000000000..ad55ba026ff972561376164e625ec6fa057424b5 --- /dev/null +++ b/RrZ8-1w7iok.txt @@ -0,0 +1,232 @@ +Let's review what happens when the CPU accesses +a non-resident virtual page, i.e., a page + +with its resident bit set to 0. + +In the example shown here, the CPU is trying +to access virtual page 5. + +In this case, the MMU signals a page fault +exception, causing the CPU to suspend execution + +of the program and switch to the page fault +handler, which is code that deals with the + +page fault. + +The handler starts by either finding an unused +physical page or, if necessary, creating an + +unused page by selecting an in-use page and +making it available. + +In our example, the handler has chosen virtual +page 1 for reuse. + +If the selected page is dirty, i.e., its D +bit is 1 indicating that its contents have + +changed since being read from secondary storage, +write it back to secondary storage. + +Finally, mark the selected virtual page as +no longer resident. + +In the "after" figure, we see that the R bit +for virtual page 1 has been set to 0. + +Now physical page 4 is available for re-use. + +Are there any restrictions on which page we +can select? + +Obviously, we can't select the page that holds +the code for the page fault handler. + +Pages immune from selection are called "wired" +pages. + +And it would very inefficient to choose the +page that holds the code that made the initial + +memory access, since we expect to start executing +that code as soon as we finish handling the + +page fault. + +The optimal strategy would be to choose the +page whose next use will occur farthest in + +the future. + +But, of course, this involves knowledge of +future execution paths and so isn't a realizable + +strategy. + +Wikipedia provides a nice description of the +many strategies for choosing a replacement + +page, with their various tradeoffs between +ease of implementation and impact on the rate + +of page faults - +see the URL given at the bottom of the slide. + +The aging algorithm they describe is frequently +used since it offers near optimal performance + +at a moderate implementation cost. + +Next, the desired virtual page is read from +secondary storage into the selected physical + +page. + +In our example, virtual page 5 is now loaded +into physical page 4. + +Then the R bit and PPN fields in the page +table entry for virtual page 5 are updated + +to indicate that the contents of that virtual +page now reside in physical page 4. + +Finally the handler is finished and execution +of the original program is resumed, re-executing + +the instruction that caused the page fault. + +Since the page map has been updated, this +time the access succeeds and execution continues. + +To double-check our understanding of page +faults, let's run through an example. + +Here's the same setup as in our previous example, +but this time consider a store instruction + +that's making an access to virtual address +0x600, which is located on virtual page 6. + +Checking the page table entry for VPN 6, we +see that its R bit 0 indicating that it is + +NOT resident in main memory, which causes +a page fault exception. + +The page fault handler selects VPN 0xE for +replacement since we've been told in the setup + +that it's the least-recently-used page. + +The page table entry for VPN 0xE has D=1 so +the handler writes the contents of VPN 0xE, + +which is found in PPN 0x5, to secondary storage. + +Then it updates the page table to indicate +that VPN 0xE is no longer resident. + +Next, the contents of VPN 0x6 are read from +secondary storage into the now available PPN + +0x5. + +Now the handler updates the page table entry +for VPN 0x6 to indicate that it's resident + +in PPN 0x5. + +The page fault handler has completed its work, +so program execution resumes and the ST instruction + +is re-executed. + +This time the MMU is able to translate virtual +address 0x600 to physical address 0x500. + +And since the ST instruction modifies the +contents of VPN 0x6, its D bit is set to 1. + +Whew! + +We're done :) +We can think of the work of the MMU as being + +divided into two tasks, which as computer +scientists, we would think of as two procedures. + +In this formulation the information in the +page map is held in several arrays: the R + +array holds the resident bits, +the D array holds the dirty bits, the PPN + +array holds the physical page numbers, +and the DiskAdr array holds the location in + +secondary storage for each virtual page. + +The VtoP procedure is invoked on each memory +access to translate the virtual address into + +a physical address. + +If the requested virtual page is not resident, +the PageFault procedure is invoked to make + +the page resident. + +Once the requested page is resident, the VPN +is used as an index to lookup the corresponding + +PPN, which is then concatenated with the page +offset to form the physical address. + +The PageFault routine starts by selecting +a virtual page to be replaced, writing out + +its contents if it's dirty. + +The selected page is then marked as not resident. + +Finally the desired virtual page is read from +secondary storage and the page map information + +updated to reflect that it's now resident +in the newly filled physical page. + +We'll use hardware to implement the VtoP functionality +since it's needed for every memory access. + +The call to the PageFault procedure is accomplished +via a page fault exception, which directs + +the CPU to execute the appropriate handler +software that contains the PageFault procedure. + +This is a good strategy to pursue in all our +implementation choices: use hardware for the + +operations that need to be fast, but use exceptions +to handle the (hopefully infrequent) exceptional + +cases in software. + +Since the software is executed by the CPU, +which is itself a piece of hardware, what + +we're really doing is making the tradeoff +between using special-purpose hardware (e.g., + +the MMU) or using general-purpose hardware +(e.g., the CPU). + +In general, one should be skeptical of proposals +to use special-purpose hardware, reserving + +that choice for operations that truly are +commonplace and whose performance is critical + +to the overall performance of the system. \ No newline at end of file diff --git a/SP21-5q2uzw.txt b/SP21-5q2uzw.txt new file mode 100644 index 0000000000000000000000000000000000000000..08c1dd9448c0249500a22372e10dce7874734580 --- /dev/null +++ b/SP21-5q2uzw.txt @@ -0,0 +1,6699 @@ +align:start position:0% + +foreign + + align:start position:0% + + + + align:start position:0% + +so let's talk about processes and + + align:start position:0% +so let's talk about processes and + + + align:start position:0% +so let's talk about processes and +thermodynamics + + align:start position:0% + + + + align:start position:0% + +right so we talked about Thermo being + + align:start position:0% +right so we talked about Thermo being + + + align:start position:0% +right so we talked about Thermo being +this weird thing + + align:start position:0% + + + + align:start position:0% + +that can tell you about + + align:start position:0% +that can tell you about + + + align:start position:0% +that can tell you about +the starting state + + align:start position:0% + + + + align:start position:0% + +in the final state + + align:start position:0% + + + + align:start position:0% + +but + + align:start position:0% +but + + + align:start position:0% +but +doesn't really have a clue as to the + + align:start position:0% +doesn't really have a clue as to the + + + align:start position:0% +doesn't really have a clue as to the +process that takes you from one to the + + align:start position:0% +process that takes you from one to the + + + align:start position:0% +process that takes you from one to the +other + + align:start position:0% +other + + + align:start position:0% +other +that is Thermo + + align:start position:0% +that is Thermo + + + align:start position:0% +that is Thermo +doesn't describe + + align:start position:0% + + + + align:start position:0% + +real world processes + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +but that doesn't mean it's useless the + + align:start position:0% +but that doesn't mean it's useless the + + + align:start position:0% +but that doesn't mean it's useless the +concept of State functions + + align:start position:0% + + + + align:start position:0% + +which are history independent + + align:start position:0% + + + + align:start position:0% + +allows us to make predictions + + align:start position:0% + + + + align:start position:0% + +right so for example if someone told you + + align:start position:0% +right so for example if someone told you + + + align:start position:0% +right so for example if someone told you +the pressure temperature and volume of + + align:start position:0% +the pressure temperature and volume of + + + align:start position:0% +the pressure temperature and volume of +the system at the beginning + + align:start position:0% +the system at the beginning + + + align:start position:0% +the system at the beginning +and then totally do the pressure and + + align:start position:0% +and then totally do the pressure and + + + align:start position:0% +and then totally do the pressure and +temperature of the system at the end + + align:start position:0% +temperature of the system at the end + + + align:start position:0% +temperature of the system at the end +with that information you could + + align:start position:0% +with that information you could + + + align:start position:0% +with that information you could +calculate the volume without knowing + + align:start position:0% +calculate the volume without knowing + + + align:start position:0% +calculate the volume without knowing +the process that took it from A to B + + align:start position:0% + + + + align:start position:0% + +so that's useful + + align:start position:0% + + + + align:start position:0% + +so here's the property of State + + align:start position:0% +so here's the property of State + + + align:start position:0% +so here's the property of State +functions any process + + align:start position:0% + + + + align:start position:0% + +connecting + + align:start position:0% + + + + align:start position:0% + +A to B will give same results + + align:start position:0% +A to B will give same results + + + align:start position:0% +A to B will give same results +it's like + + align:start position:0% + + + + align:start position:0% + +for the final state + + align:start position:0% + + + + align:start position:0% + +is the final State variables + + align:start position:0% + + + + align:start position:0% + +because they are State variables + + align:start position:0% + + + + align:start position:0% + +so you want to calculate something + + align:start position:0% +so you want to calculate something + + + align:start position:0% +so you want to calculate something +you want to do the easiest calculation + + align:start position:0% +you want to do the easiest calculation + + + align:start position:0% +you want to do the easiest calculation +you can conceptualize + + align:start position:0% + + + + align:start position:0% + +the simplest process to calculate + + align:start position:0% + + + + align:start position:0% + +so in the same way that we choose a + + align:start position:0% +so in the same way that we choose a + + + align:start position:0% +so in the same way that we choose a +system + + align:start position:0% +system + + + align:start position:0% +system +components and its boundaries out of + + align:start position:0% +components and its boundaries out of + + + align:start position:0% +components and its boundaries out of +convenience + + align:start position:0% +convenience + + + align:start position:0% +convenience +depending on the problem we're trying to + + align:start position:0% +depending on the problem we're trying to + + + align:start position:0% +depending on the problem we're trying to +solve you + + align:start position:0% +solve you + + + align:start position:0% +solve you +calculate the simplest process + + align:start position:0% +calculate the simplest process + + + align:start position:0% +calculate the simplest process +to calculate out of convenience not + + align:start position:0% +to calculate out of convenience not + + + align:start position:0% +to calculate out of convenience not +necessarily the process that nature + + align:start position:0% +necessarily the process that nature + + + align:start position:0% +necessarily the process that nature +actually takes + + align:start position:0% + + + + align:start position:0% + +so the simplest process is to calculate + + align:start position:0% + + + + align:start position:0% + +are reversible + + align:start position:0% + + + + align:start position:0% + +so reversible process that's that's a + + align:start position:0% +so reversible process that's that's a + + + align:start position:0% +so reversible process that's that's a +New Concept + + align:start position:0% +New Concept + + + align:start position:0% +New Concept +That's A New Concept for us and it has a + + align:start position:0% +That's A New Concept for us and it has a + + + align:start position:0% +That's A New Concept for us and it has a +very deep and important thermodynamic + + align:start position:0% +very deep and important thermodynamic + + + align:start position:0% +very deep and important thermodynamic +meaning it means a process that does not + + align:start position:0% +meaning it means a process that does not + + + align:start position:0% +meaning it means a process that does not +change the entropy of the universe that + + align:start position:0% +change the entropy of the universe that + + + align:start position:0% +change the entropy of the universe that +is a system plus its surroundings + + align:start position:0% +is a system plus its surroundings + + + align:start position:0% +is a system plus its surroundings +and we'll see that in the next couple of + + align:start position:0% +and we'll see that in the next couple of + + + align:start position:0% +and we'll see that in the next couple of +lectures + + align:start position:0% +lectures + + + align:start position:0% +lectures +reversible processes have these + + align:start position:0% +reversible processes have these + + + align:start position:0% +reversible processes have these +properties + + align:start position:0% + + + + align:start position:0% + +the system plus surroundings + + align:start position:0% + + + + align:start position:0% + +are in equilibrium + + align:start position:0% + + + + align:start position:0% + +at all times + + align:start position:0% + + + + align:start position:0% + +that's an assumption + + align:start position:0% +that's an assumption + + + align:start position:0% +that's an assumption +all right this violates + + align:start position:0% + + + + align:start position:0% + +our day + + align:start position:0% +our day + + + align:start position:0% +our day +to day notion of an arrow of time + + align:start position:0% + + + + align:start position:0% + +it's really inconsistent with most of + + align:start position:0% +it's really inconsistent with most of + + + align:start position:0% +it's really inconsistent with most of +our experience + + align:start position:0% +our experience + + + align:start position:0% +our experience +right + + align:start position:0% + + + + align:start position:0% + +in practice + + align:start position:0% + + + + align:start position:0% + +in practice a reversible process would + + align:start position:0% +in practice a reversible process would + + + align:start position:0% +in practice a reversible process would +take forever + + align:start position:0% +take forever + + + align:start position:0% +take forever +so we're imagining a process which + + align:start position:0% +so we're imagining a process which + + + align:start position:0% +so we're imagining a process which +doesn't actually exist but it makes a + + align:start position:0% +doesn't actually exist but it makes a + + + align:start position:0% +doesn't actually exist but it makes a +calculation easier + + align:start position:0% +calculation easier + + + align:start position:0% +calculation easier +so in order for a process to be in + + align:start position:0% +so in order for a process to be in + + + align:start position:0% +so in order for a process to be in +equilibrium at all times it has to go + + align:start position:0% +equilibrium at all times it has to go + + + align:start position:0% +equilibrium at all times it has to go +arbitrarily slowly + + align:start position:0% + + + + align:start position:0% + +in order for a process to be able to go + + align:start position:0% +in order for a process to be able to go + + + align:start position:0% +in order for a process to be able to go +forwards or backwards we need to be able + + align:start position:0% +forwards or backwards we need to be able + + + align:start position:0% +forwards or backwards we need to be able +to play the movie + + align:start position:0% +to play the movie + + + align:start position:0% +to play the movie +forwards or backwards + + align:start position:0% +forwards or backwards + + + align:start position:0% +forwards or backwards +without being able to tell + + align:start position:0% +without being able to tell + + + align:start position:0% +without being able to tell +which one is forwards and which one is + + align:start position:0% +which one is forwards and which one is + + + align:start position:0% +which one is forwards and which one is +backwards that violates our day-to-day + + align:start position:0% +backwards that violates our day-to-day + + + align:start position:0% +backwards that violates our day-to-day +notion of the arrow of time + + align:start position:0% +notion of the arrow of time + + + align:start position:0% +notion of the arrow of time +and the requirement to go arbitrarily + + align:start position:0% +and the requirement to go arbitrarily + + + align:start position:0% +and the requirement to go arbitrarily +slowly means that in practice and a + + align:start position:0% +slowly means that in practice and a + + + align:start position:0% +slowly means that in practice and a +reversible process would take forever + + align:start position:0% +reversible process would take forever + + + align:start position:0% +reversible process would take forever +but it makes calculations really easy + + align:start position:0% + + + + align:start position:0% + +is that surprising to anybody + + align:start position:0% +is that surprising to anybody + + + align:start position:0% +is that surprising to anybody +or we're comfortable with the concept of + + align:start position:0% +or we're comfortable with the concept of + + + align:start position:0% +or we're comfortable with the concept of +a reversible process + + align:start position:0% +a reversible process + + + align:start position:0% +a reversible process +none of your day-to-day processes are + + align:start position:0% +none of your day-to-day processes are + + + align:start position:0% +none of your day-to-day processes are +reversible + + align:start position:0% + + + + align:start position:0% + +if you think you you think of one + + align:start position:0% +if you think you you think of one + + + align:start position:0% +if you think you you think of one +um let's toss it out and we can try to + + align:start position:0% +um let's toss it out and we can try to + + + align:start position:0% +um let's toss it out and we can try to +figure out why it's not those are kind + + align:start position:0% +figure out why it's not those are kind + + + align:start position:0% +figure out why it's not those are kind +of fun thought experiments + + align:start position:0% + + + + align:start position:0% + +okay let's describe processes + + align:start position:0% + + + + align:start position:0% + +in the last lecture we described systems + + align:start position:0% +in the last lecture we described systems + + + align:start position:0% +in the last lecture we described systems +now we're going to describe processes + + align:start position:0% +now we're going to describe processes + + + align:start position:0% +now we're going to describe processes +all right so things you can do to a + + align:start position:0% +all right so things you can do to a + + + align:start position:0% +all right so things you can do to a +system you can work on it + + align:start position:0% + + + + align:start position:0% + +foreign + + align:start position:0% +foreign + + + align:start position:0% +foreign +you can heat it + + align:start position:0% +you can heat it + + + align:start position:0% +you can heat it +or you could add + + align:start position:0% +or you could add + + + align:start position:0% +or you could add +or subtract + + align:start position:0% + + + + align:start position:0% + +stuff + + align:start position:0% + + + + align:start position:0% + +okay these are things you can do + + align:start position:0% +okay these are things you can do + + + align:start position:0% +okay these are things you can do +these are + + align:start position:0% +these are + + + align:start position:0% +these are +verbs in thermal + + align:start position:0% + + + + align:start position:0% + +all of these are verbs in thermal + + align:start position:0% +all of these are verbs in thermal + + + align:start position:0% +all of these are verbs in thermal +they're actions that you do on a system + + align:start position:0% +they're actions that you do on a system + + + align:start position:0% +they're actions that you do on a system +okay work what is work + + align:start position:0% +okay work what is work + + + align:start position:0% +okay work what is work +it's a mechanical way of exchanging + + align:start position:0% +it's a mechanical way of exchanging + + + align:start position:0% +it's a mechanical way of exchanging +energy + + align:start position:0% +energy + + + align:start position:0% +energy +mechanical + + align:start position:0% +mechanical + + + align:start position:0% +mechanical +Exchange + + align:start position:0% + + + + align:start position:0% + +of energy + + align:start position:0% + + + + align:start position:0% + +so we use w + + align:start position:0% +so we use w + + + align:start position:0% +so we use w +and what's that + + align:start position:0% +and what's that + + + align:start position:0% +and what's that +kilogram meters squared per second + + align:start position:0% +kilogram meters squared per second + + + align:start position:0% +kilogram meters squared per second +squared + + align:start position:0% +squared + + + align:start position:0% +squared +as the units of + + align:start position:0% +as the units of + + + align:start position:0% +as the units of +energy + + align:start position:0% +energy + + + align:start position:0% +energy +right just a little bit of dimensional + + align:start position:0% +right just a little bit of dimensional + + + align:start position:0% +right just a little bit of dimensional +analysis you guys flip separate that out + + align:start position:0% +analysis you guys flip separate that out + + + align:start position:0% +analysis you guys flip separate that out +it's kilogram meter per second squared + + align:start position:0% +it's kilogram meter per second squared + + + align:start position:0% +it's kilogram meter per second squared +per meter right + + align:start position:0% +per meter right + + + align:start position:0% +per meter right +equals fourths times distance + + align:start position:0% + + + + align:start position:0% + +right that's Force + + align:start position:0% +right that's Force + + + align:start position:0% +right that's Force +and that's distance that's fine + + align:start position:0% +and that's distance that's fine + + + align:start position:0% +and that's distance that's fine +um + + align:start position:0% +um + + + align:start position:0% +um +in thermo we we normally separate that + + align:start position:0% +in thermo we we normally separate that + + + align:start position:0% +in thermo we we normally separate that +out a little bit differently + + align:start position:0% +out a little bit differently + + + align:start position:0% +out a little bit differently +we grab kilogram + + align:start position:0% +we grab kilogram + + + align:start position:0% +we grab kilogram +per meter + + align:start position:0% +per meter + + + align:start position:0% +per meter +per second squared + + align:start position:0% + + + + align:start position:0% + +okay what do I need what do I need to + + align:start position:0% +okay what do I need what do I need to + + + align:start position:0% +okay what do I need what do I need to +multiply this by in order to get the + + align:start position:0% +multiply this by in order to get the + + + align:start position:0% +multiply this by in order to get the +same units + + align:start position:0% + + + + align:start position:0% + +what do I need + + align:start position:0% +what do I need + + + align:start position:0% +what do I need +volume meters volume + + align:start position:0% +volume meters volume + + + align:start position:0% +volume meters volume +yeah meters cubed + + align:start position:0% +yeah meters cubed + + + align:start position:0% +yeah meters cubed +so what's this this is a pressure + + align:start position:0% + + + + align:start position:0% + +times the volume + + align:start position:0% +times the volume + + + align:start position:0% +times the volume +so when you take intro mechanics let's + + align:start position:0% +so when you take intro mechanics let's + + + align:start position:0% +so when you take intro mechanics let's +say in a physics class you normally do + + align:start position:0% +say in a physics class you normally do + + + align:start position:0% +say in a physics class you normally do +force times distance work + + align:start position:0% +force times distance work + + + align:start position:0% +force times distance work +but when you take into a thermodynamics + + align:start position:0% +but when you take into a thermodynamics + + + align:start position:0% +but when you take into a thermodynamics +you normally do pressure volume work + + align:start position:0% +you normally do pressure volume work + + + align:start position:0% +you normally do pressure volume work +of course the units work out the same + + align:start position:0% +of course the units work out the same + + + align:start position:0% +of course the units work out the same +but this is p pdv work we call it okay + + align:start position:0% +but this is p pdv work we call it okay + + + align:start position:0% +but this is p pdv work we call it okay +let's work + + align:start position:0% +let's work + + + align:start position:0% +let's work +what about heat + + align:start position:0% +what about heat + + + align:start position:0% +what about heat +today all right well he is kind of + + align:start position:0% +today all right well he is kind of + + + align:start position:0% +today all right well he is kind of +difficult to ex to Define actually + + align:start position:0% + + + + align:start position:0% + +he is a process + + align:start position:0% + + + + align:start position:0% + +that exchanges energy + + align:start position:0% + + + + align:start position:0% + +without + + align:start position:0% + + + + align:start position:0% + +mechanical + + align:start position:0% + + + + align:start position:0% + +work + + align:start position:0% + + + + align:start position:0% + +or mass Exchange + + align:start position:0% + + + + align:start position:0% + +so heat is defined by what it's not + + align:start position:0% +so heat is defined by what it's not + + + align:start position:0% +so heat is defined by what it's not +it's kind of a weird thing + + align:start position:0% + + + + align:start position:0% + +and for heat we're going to use Q yes I + + align:start position:0% +and for heat we're going to use Q yes I + + + align:start position:0% +and for heat we're going to use Q yes I +work as W heat is Q they both have units + + align:start position:0% +work as W heat is Q they both have units + + + align:start position:0% +work as W heat is Q they both have units +of energy joules + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +all right so we have described State + + align:start position:0% +all right so we have described State + + + align:start position:0% +all right so we have described State +variables which are history independent + + align:start position:0% +variables which are history independent + + + align:start position:0% +variables which are history independent +but we also have process variables + + align:start position:0% + + + + align:start position:0% + +that are + + align:start position:0% +that are + + + align:start position:0% +that are +process dependent + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so infinitesimal increments + + align:start position:0% +so infinitesimal increments + + + align:start position:0% +so infinitesimal increments +infinitesimal + + align:start position:0% + + + + align:start position:0% + +of process variables + + align:start position:0% + + + + align:start position:0% + +are denoted + + align:start position:0% + + + + align:start position:0% + +as + + align:start position:0% +as + + + align:start position:0% +as +I'm going to put this in in quotes + + align:start position:0% +I'm going to put this in in quotes + + + align:start position:0% +I'm going to put this in in quotes +inexact differentials + + align:start position:0% + + + + align:start position:0% + +that is DQ + + align:start position:0% +that is DQ + + + align:start position:0% +that is DQ +D work + + align:start position:0% + + + + align:start position:0% + +using + + align:start position:0% +using + + + align:start position:0% +using +D not + + align:start position:0% +D not + + + align:start position:0% +D not +d + + align:start position:0% + + + + align:start position:0% + +this is annoying don't blame don't shoot + + align:start position:0% +this is annoying don't blame don't shoot + + + align:start position:0% +this is annoying don't blame don't shoot +the messenger this is one really key + + align:start position:0% +the messenger this is one really key + + + align:start position:0% +the messenger this is one really key +area where Thermo deviates from + + align:start position:0% +area where Thermo deviates from + + + align:start position:0% +area where Thermo deviates from +multivariable calculus + + align:start position:0% +multivariable calculus + + + align:start position:0% +multivariable calculus +so um try not to get confused because it + + align:start position:0% +so um try not to get confused because it + + + align:start position:0% +so um try not to get confused because it +is confusing + + align:start position:0% + + + + align:start position:0% + +there's a mini lecture I recorded it's + + align:start position:0% +there's a mini lecture I recorded it's + + + align:start position:0% +there's a mini lecture I recorded it's +up on the website called the 3DS of + + align:start position:0% +up on the website called the 3DS of + + + align:start position:0% +up on the website called the 3DS of +thermodynamics because it gets kind of + + align:start position:0% +thermodynamics because it gets kind of + + + align:start position:0% +thermodynamics because it gets kind of +harried we use a lot of Deeds + + align:start position:0% +harried we use a lot of Deeds + + + align:start position:0% +harried we use a lot of Deeds +to denote differences so hopefully + + align:start position:0% +to denote differences so hopefully + + + align:start position:0% +to denote differences so hopefully +that's useful at some point if not now + + align:start position:0% +that's useful at some point if not now + + + align:start position:0% +that's useful at some point if not now +then maybe in a week or two in the quest + + align:start position:0% +then maybe in a week or two in the quest + + + align:start position:0% +then maybe in a week or two in the quest +okay + + align:start position:0% +okay + + + align:start position:0% +okay +in thermodynamics this Greek d + + align:start position:0% +in thermodynamics this Greek d + + + align:start position:0% +in thermodynamics this Greek d +means + + align:start position:0% + + + + align:start position:0% + +path dependent + + align:start position:0% + + + + align:start position:0% + +that's what it means + + align:start position:0% + + + + align:start position:0% + +so what is a process variable if you + + align:start position:0% +so what is a process variable if you + + + align:start position:0% +so what is a process variable if you +have a state a + + align:start position:0% +have a state a + + + align:start position:0% +have a state a +State B + + align:start position:0% +State B + + + align:start position:0% +State B +a process variable + + align:start position:0% +a process variable + + + align:start position:0% +a process variable +is a variable which depends on the + + align:start position:0% +is a variable which depends on the + + + align:start position:0% +is a variable which depends on the +process it takes to get from A to B + + align:start position:0% + + + + align:start position:0% + +right + + align:start position:0% +right + + + align:start position:0% +right +so you might have path one + + align:start position:0% + + + + align:start position:0% + +with work one and heat one + + align:start position:0% +with work one and heat one + + + align:start position:0% +with work one and heat one +and path two + + align:start position:0% + + + + align:start position:0% + +with work to + + align:start position:0% +with work to + + + align:start position:0% +with work to +and heat too and those are different + + align:start position:0% +and heat too and those are different + + + align:start position:0% +and heat too and those are different +because they're not State variables + + align:start position:0% +because they're not State variables + + + align:start position:0% +because they're not State variables +they're process variables + + align:start position:0% + + + + align:start position:0% + +if we were on campus you know the the + + align:start position:0% +if we were on campus you know the the + + + align:start position:0% +if we were on campus you know the the +nice analogy to use is the amount of + + align:start position:0% +nice analogy to use is the amount of + + + align:start position:0% +nice analogy to use is the amount of +work you need to get from the second + + align:start position:0% +work you need to get from the second + + + align:start position:0% +work you need to get from the second +floor of building one to the fifth floor + + align:start position:0% +floor of building one to the fifth floor + + + align:start position:0% +floor of building one to the fifth floor +of building 32. or just pick a pair like + + align:start position:0% +of building 32. or just pick a pair like + + + align:start position:0% +of building 32. or just pick a pair like +that + + align:start position:0% +that + + + align:start position:0% +that +um there's Myriad ways of connecting + + align:start position:0% +um there's Myriad ways of connecting + + + align:start position:0% +um there's Myriad ways of connecting +those here because campus is connected + + align:start position:0% +those here because campus is connected + + + align:start position:0% +those here because campus is connected +you can go upstairs and downstairs you + + align:start position:0% +you can go upstairs and downstairs you + + + align:start position:0% +you can go upstairs and downstairs you +can take elevators you could you could + + align:start position:0% +can take elevators you could you could + + + align:start position:0% +can take elevators you could you could +get between those two points um in a + + align:start position:0% +get between those two points um in a + + + align:start position:0% +get between those two points um in a +very large number of different + + align:start position:0% +very large number of different + + + align:start position:0% +very large number of different +combinations + + align:start position:0% +combinations + + + align:start position:0% +combinations +and the amount of mechanical work you + + align:start position:0% +and the amount of mechanical work you + + + align:start position:0% +and the amount of mechanical work you +need to do + + align:start position:0% +need to do + + + align:start position:0% +need to do +will vary with combination + + align:start position:0% +will vary with combination + + + align:start position:0% +will vary with combination +but the change in your gravitational + + align:start position:0% +but the change in your gravitational + + + align:start position:0% +but the change in your gravitational +potential energy + + align:start position:0% +potential energy + + + align:start position:0% +potential energy +between the starting and final Point + + align:start position:0% +between the starting and final Point + + + align:start position:0% +between the starting and final Point +that's a fixed change + + align:start position:0% +that's a fixed change + + + align:start position:0% +that's a fixed change +that's an example of uh process + + align:start position:0% +that's an example of uh process + + + align:start position:0% +that's an example of uh process +variables versus State variables + + align:start position:0% +variables versus State variables + + + align:start position:0% +variables versus State variables +but we're not on campus it's so sad + + align:start position:0% +but we're not on campus it's so sad + + + align:start position:0% +but we're not on campus it's so sad +you're just going to have to imagine all + + align:start position:0% +you're just going to have to imagine all + + + align:start position:0% +you're just going to have to imagine all +the work you'd have to do to get from + + align:start position:0% +the work you'd have to do to get from + + + align:start position:0% +the work you'd have to do to get from +building one to building 32. + + align:start position:0% +building one to building 32. + + + align:start position:0% +building one to building 32. +okay so this is infinitesimal increments + + align:start position:0% +okay so this is infinitesimal increments + + + align:start position:0% +okay so this is infinitesimal increments +and process variables + + align:start position:0% +and process variables + + + align:start position:0% +and process variables +infinitesimal + + align:start position:0% + + + + align:start position:0% + +I think I need new markers + + align:start position:0% +I think I need new markers + + + align:start position:0% +I think I need new markers +and state variables + + align:start position:0% + + + + align:start position:0% + +are denoted + + align:start position:0% + + + + align:start position:0% + +as exact differentials + + align:start position:0% + + + + align:start position:0% + +so for example d t + + align:start position:0% +so for example d t + + + align:start position:0% +so for example d t +d p + + align:start position:0% +d p + + + align:start position:0% +d p +d v + + align:start position:0% +d v + + + align:start position:0% +d v +and so on + + align:start position:0% +and so on + + + align:start position:0% +and so on +right using + + align:start position:0% + + + + align:start position:0% + +irregular lowercase D agent + + align:start position:0% + + + + align:start position:0% + +a total differential in calculus okay + + align:start position:0% + + + + align:start position:0% + +so all I can do is tell you that + + align:start position:0% +so all I can do is tell you that + + + align:start position:0% +so all I can do is tell you that +um understanding that will can only come + + align:start position:0% +um understanding that will can only come + + + align:start position:0% +um understanding that will can only come +through practice + + align:start position:0% +through practice + + + align:start position:0% +through practice +but towards the beginning of the class + + align:start position:0% +but towards the beginning of the class + + + align:start position:0% +but towards the beginning of the class +so all I can do is tell you I think I'm + + align:start position:0% +so all I can do is tell you I think I'm + + + align:start position:0% +so all I can do is tell you I think I'm +going to try to switch to purple so + + align:start position:0% +going to try to switch to purple so + + + align:start position:0% +going to try to switch to purple so +things show up a little better + + align:start position:0% +things show up a little better + + + align:start position:0% +things show up a little better +all right so let's talk about how we + + align:start position:0% +all right so let's talk about how we + + + align:start position:0% +all right so let's talk about how we +classify processes + + align:start position:0% + + + + align:start position:0% + +all right so an isothermal process + + align:start position:0% + + + + align:start position:0% + +is a process at fixed temperature + + align:start position:0% + + + + align:start position:0% + +what about an adiabatic process anybody + + align:start position:0% +what about an adiabatic process anybody + + + align:start position:0% +what about an adiabatic process anybody +know + + align:start position:0% + + + + align:start position:0% + +it's not very fast + + align:start position:0% + + + + align:start position:0% + +I had a couple things which are + + align:start position:0% +I had a couple things which are + + + align:start position:0% +I had a couple things which are +equivalent actually somebody said very + + align:start position:0% +equivalent actually somebody said very + + + align:start position:0% +equivalent actually somebody said very +fast + + align:start position:0% +fast + + + align:start position:0% +fast +somebody else said no heat flow across + + align:start position:0% +somebody else said no heat flow across + + + align:start position:0% +somebody else said no heat flow across +the boundary + + align:start position:0% +the boundary + + + align:start position:0% +the boundary +so the strict definition is no heating + + align:start position:0% +so the strict definition is no heating + + + align:start position:0% +so the strict definition is no heating +across the boundary + + align:start position:0% + + + + align:start position:0% + +okay in reality heat will always flow + + align:start position:0% +okay in reality heat will always flow + + + align:start position:0% +okay in reality heat will always flow +from a hot object to a cold object + + align:start position:0% +from a hot object to a cold object + + + align:start position:0% +from a hot object to a cold object +but if you've insulated your system + + align:start position:0% +but if you've insulated your system + + + align:start position:0% +but if you've insulated your system +whether it's your house + + align:start position:0% +whether it's your house + + + align:start position:0% +whether it's your house +um + + align:start position:0% +um + + + align:start position:0% +um +or a beaker + + align:start position:0% +or a beaker + + + align:start position:0% +or a beaker +in the lab + + align:start position:0% +in the lab + + + align:start position:0% +in the lab +then that slow that heat flow could be + + align:start position:0% +then that slow that heat flow could be + + + align:start position:0% +then that slow that heat flow could be +slowed down + + align:start position:0% +slowed down + + + align:start position:0% +slowed down +so one way of approximating an + + align:start position:0% +so one way of approximating an + + + align:start position:0% +so one way of approximating an +adiabiotic process is to run it quickly + + align:start position:0% +adiabiotic process is to run it quickly + + + align:start position:0% +adiabiotic process is to run it quickly +if you run a process very quickly + + align:start position:0% +if you run a process very quickly + + + align:start position:0% +if you run a process very quickly +the entire process can run before an + + align:start position:0% +the entire process can run before an + + + align:start position:0% +the entire process can run before an +appreciable amount of heat flows across + + align:start position:0% +appreciable amount of heat flows across + + + align:start position:0% +appreciable amount of heat flows across +the boundary + + align:start position:0% +the boundary + + + align:start position:0% +the boundary +so so that's why a fast process can be + + align:start position:0% +so so that's why a fast process can be + + + align:start position:0% +so so that's why a fast process can be +equivalent so I like both of those + + align:start position:0% +equivalent so I like both of those + + + align:start position:0% +equivalent so I like both of those +answers + + align:start position:0% +answers + + + align:start position:0% +answers +all right isobaric + + align:start position:0% + + + + align:start position:0% + +isobaric process is at fixed p + + align:start position:0% + + + + align:start position:0% + +and um isocoric + + align:start position:0% +and um isocoric + + + align:start position:0% +and um isocoric +we don't use as much + + align:start position:0% +we don't use as much + + + align:start position:0% +we don't use as much +is fixed B + + align:start position:0% + + + + align:start position:0% + +and we'll see that means that there can + + align:start position:0% +and we'll see that means that there can + + + align:start position:0% +and we'll see that means that there can +be no work done on the system if the + + align:start position:0% +be no work done on the system if the + + + align:start position:0% +be no work done on the system if the +volume is fixed + + align:start position:0% +volume is fixed + + + align:start position:0% +volume is fixed +all right and then there is + + align:start position:0% +all right and then there is + + + align:start position:0% +all right and then there is +classifying + + align:start position:0% +classifying + + + align:start position:0% +classifying +boundaries + + align:start position:0% + + + + align:start position:0% + +we've seen this a little bit so far + + align:start position:0% +we've seen this a little bit so far + + + align:start position:0% +we've seen this a little bit so far +but + + align:start position:0% +but + + + align:start position:0% +but +as a practical matter + + align:start position:0% +as a practical matter + + + align:start position:0% +as a practical matter +the way that we set up processes are by + + align:start position:0% +the way that we set up processes are by + + + align:start position:0% +the way that we set up processes are by +defining boundaries + + align:start position:0% +defining boundaries + + + align:start position:0% +defining boundaries +so for example an insulating boundary + + align:start position:0% + + + + align:start position:0% + +a no or a say slow heat flow + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +diathermal + + align:start position:0% + + + + align:start position:0% + +he + + align:start position:0% +he + + + align:start position:0% +he +but + + align:start position:0% +but + + + align:start position:0% +but +no Mass transfer + + align:start position:0% + + + + align:start position:0% + +open or closed + + align:start position:0% + + + + align:start position:0% + +is Mass + + align:start position:0% + + + + align:start position:0% + +transfer allowed + + align:start position:0% + + + + align:start position:0% + +or disallowed + + align:start position:0% + + + + align:start position:0% + +and rigid + + align:start position:0% +and rigid + + + align:start position:0% +and rigid +foreign + + align:start position:0% + + + + align:start position:0% + +okay so when we run processes we can + + align:start position:0% +okay so when we run processes we can + + + align:start position:0% +okay so when we run processes we can +somewhat determine what kind of process + + align:start position:0% +somewhat determine what kind of process + + + align:start position:0% +somewhat determine what kind of process +we're going to run by setting up the + + align:start position:0% +we're going to run by setting up the + + + align:start position:0% +we're going to run by setting up the +boundary conditions + + align:start position:0% +boundary conditions + + + align:start position:0% +boundary conditions +and this is a practical thing this is a + + align:start position:0% +and this is a practical thing this is a + + + align:start position:0% +and this is a practical thing this is a +practical matter and all of us who run + + align:start position:0% +practical matter and all of us who run + + + align:start position:0% +practical matter and all of us who run +Labs + + align:start position:0% +Labs + + + align:start position:0% +Labs +um we do this every day in various ways + + align:start position:0% + + + + align:start position:0% + +all right so classifying processes + + align:start position:0% +all right so classifying processes + + + align:start position:0% +all right so classifying processes +classifying boundaries and so forth okay + + align:start position:0% +classifying boundaries and so forth okay + + + align:start position:0% +classifying boundaries and so forth okay +let's talk about other things associated + + align:start position:0% +let's talk about other things associated + + + align:start position:0% +let's talk about other things associated +with processes what about heat capacity + + align:start position:0% +with processes what about heat capacity + + + align:start position:0% +with processes what about heat capacity +most folks have encountered heat + + align:start position:0% +most folks have encountered heat + + + align:start position:0% +most folks have encountered heat +capacity before heat capacity we're + + align:start position:0% +capacity before heat capacity we're + + + align:start position:0% +capacity before heat capacity we're +going to use C + + align:start position:0% +going to use C + + + align:start position:0% +going to use C +and it is + + align:start position:0% +and it is + + + align:start position:0% +and it is +the + + align:start position:0% +the + + + align:start position:0% +the +change in + + align:start position:0% +change in + + + align:start position:0% +change in +heat an incremental amount of heat + + align:start position:0% +heat an incremental amount of heat + + + align:start position:0% +heat an incremental amount of heat +for an incremental change of temperature + + align:start position:0% +for an incremental change of temperature + + + align:start position:0% +for an incremental change of temperature +heat increments + + align:start position:0% + + + + align:start position:0% + +temp increment + + align:start position:0% + + + + align:start position:0% + +thank you + + align:start position:0% +thank you + + + align:start position:0% +thank you +okay + + align:start position:0% +okay + + + align:start position:0% +okay +is heat capacity a state variable or a + + align:start position:0% +is heat capacity a state variable or a + + + align:start position:0% +is heat capacity a state variable or a +process variable + + align:start position:0% +process variable + + + align:start position:0% +process variable +process + + align:start position:0% +process + + + align:start position:0% +process +the process is right why is it a process + + align:start position:0% +the process is right why is it a process + + + align:start position:0% +the process is right why is it a process +variable + + align:start position:0% +variable + + + align:start position:0% +variable +um because the first like the DQ is path + + align:start position:0% +um because the first like the DQ is path + + + align:start position:0% +um because the first like the DQ is path +dependent yeah exactly it's a process + + align:start position:0% +dependent yeah exactly it's a process + + + align:start position:0% +dependent yeah exactly it's a process +variable because it depends on a process + + align:start position:0% +variable because it depends on a process + + + align:start position:0% +variable because it depends on a process +variable + + align:start position:0% +variable + + + align:start position:0% +variable +one corollary of the postula that there + + align:start position:0% +one corollary of the postula that there + + + align:start position:0% +one corollary of the postula that there +exist State functions is that state + + align:start position:0% +exist State functions is that state + + + align:start position:0% +exist State functions is that state +functions can only depend on other state + + align:start position:0% +functions can only depend on other state + + + align:start position:0% +functions can only depend on other state +functions + + align:start position:0% +functions + + + align:start position:0% +functions +so if something depends on a process + + align:start position:0% +so if something depends on a process + + + align:start position:0% +so if something depends on a process +variable it itself is a process variable + + align:start position:0% +variable it itself is a process variable + + + align:start position:0% +variable it itself is a process variable +right + + align:start position:0% +right + + + align:start position:0% +right +C is path dependent + + align:start position:0% + + + + align:start position:0% + +DQ + + align:start position:0% + + + + align:start position:0% + +is a process + + align:start position:0% + + + + align:start position:0% + +variable + + align:start position:0% +variable + + + align:start position:0% +variable +so + + align:start position:0% + + + + align:start position:0% + +it's useful + + align:start position:0% +it's useful + + + align:start position:0% +it's useful +to Define + + align:start position:0% + + + + align:start position:0% + +common processes + + align:start position:0% + + + + align:start position:0% + +I should say Define four common + + align:start position:0% +I should say Define four common + + + align:start position:0% +I should say Define four common +processes and the ones that we encounter + + align:start position:0% +processes and the ones that we encounter + + + align:start position:0% +processes and the ones that we encounter +in this class are CV + + align:start position:0% +in this class are CV + + + align:start position:0% +in this class are CV +equals DQ + + align:start position:0% +equals DQ + + + align:start position:0% +equals DQ +DT + + align:start position:0% +DT + + + align:start position:0% +DT +at fixed volume + + align:start position:0% + + + + align:start position:0% + +and CP + + align:start position:0% +and CP + + + align:start position:0% +and CP +which is d q + + align:start position:0% +which is d q + + + align:start position:0% +which is d q +d t + + align:start position:0% +d t + + + align:start position:0% +d t +at fixed pressure + + align:start position:0% + + + + align:start position:0% + +and the reason these are what you + + align:start position:0% +and the reason these are what you + + + align:start position:0% +and the reason these are what you +encounter is because these are the most + + align:start position:0% +encounter is because these are the most + + + align:start position:0% +encounter is because these are the most +useful + + align:start position:0% +useful + + + align:start position:0% +useful +you could how do you keep a system with + + align:start position:0% +you could how do you keep a system with + + + align:start position:0% +you could how do you keep a system with +fixed pressure let's say you want to + + align:start position:0% +fixed pressure let's say you want to + + + align:start position:0% +fixed pressure let's say you want to +keep a system at atmospheric pressure + + align:start position:0% +keep a system at atmospheric pressure + + + align:start position:0% +keep a system at atmospheric pressure +what's the easiest way to do that + + align:start position:0% + + + + align:start position:0% + +use like a piston + + align:start position:0% +use like a piston + + + align:start position:0% +use like a piston +that's actually I would think the + + align:start position:0% +that's actually I would think the + + + align:start position:0% +that's actually I would think the +opposite it expose it to the atmosphere + + align:start position:0% +opposite it expose it to the atmosphere + + + align:start position:0% +opposite it expose it to the atmosphere +remove the piston + + align:start position:0% +remove the piston + + + align:start position:0% +remove the piston +because if a system is exposed to the + + align:start position:0% +because if a system is exposed to the + + + align:start position:0% +because if a system is exposed to the +atmosphere + + align:start position:0% +atmosphere + + + align:start position:0% +atmosphere +it can exchange volume with the + + align:start position:0% +it can exchange volume with the + + + align:start position:0% +it can exchange volume with the +atmosphere you can get bigger or get + + align:start position:0% +atmosphere you can get bigger or get + + + align:start position:0% +atmosphere you can get bigger or get +smaller if it's higher pressure in + + align:start position:0% +smaller if it's higher pressure in + + + align:start position:0% +smaller if it's higher pressure in +atmosphere it'll push against the + + align:start position:0% +atmosphere it'll push against the + + + align:start position:0% +atmosphere it'll push against the +atmosphere and return back to + + align:start position:0% +atmosphere and return back to + + + align:start position:0% +atmosphere and return back to +atmospheric pressure if it's at lower + + align:start position:0% +atmospheric pressure if it's at lower + + + align:start position:0% +atmospheric pressure if it's at lower +pressure it will get compressed by the + + align:start position:0% +pressure it will get compressed by the + + + align:start position:0% +pressure it will get compressed by the +atmosphere and return back atmospheric + + align:start position:0% +atmosphere and return back atmospheric + + + align:start position:0% +atmosphere and return back atmospheric +pressure so the existence of a free + + align:start position:0% +pressure so the existence of a free + + + align:start position:0% +pressure so the existence of a free +surface regulates the pressure + + align:start position:0% +surface regulates the pressure + + + align:start position:0% +surface regulates the pressure +constant volume that would be a case + + align:start position:0% +constant volume that would be a case + + + align:start position:0% +constant volume that would be a case +like a piston where you have a something + + align:start position:0% +like a piston where you have a something + + + align:start position:0% +like a piston where you have a something +rigid a really rigid container you can + + align:start position:0% +rigid a really rigid container you can + + + align:start position:0% +rigid a really rigid container you can +fix the volume and then run the process + + align:start position:0% +fix the volume and then run the process + + + align:start position:0% +fix the volume and then run the process +you know the volume is not going to + + align:start position:0% +you know the volume is not going to + + + align:start position:0% +you know the volume is not going to +change + + align:start position:0% + + + + align:start position:0% + +which one of these is bigger + + align:start position:0% +which one of these is bigger + + + align:start position:0% +which one of these is bigger +that requires a little more thought + + align:start position:0% +that requires a little more thought + + + align:start position:0% +that requires a little more thought +we're going to increase the energy of + + align:start position:0% +we're going to increase the energy of + + + align:start position:0% +we're going to increase the energy of +the system by heating it + + align:start position:0% + + + + align:start position:0% + +all right we're going to increase the + + align:start position:0% +all right we're going to increase the + + + align:start position:0% +all right we're going to increase the +energy by heating it + + align:start position:0% + + + + align:start position:0% + +for a given increase in temperature + + align:start position:0% +for a given increase in temperature + + + align:start position:0% +for a given increase in temperature +right do I need to heat it more for + + align:start position:0% +right do I need to heat it more for + + + align:start position:0% +right do I need to heat it more for +fixed volume or fixed depression + + align:start position:0% +fixed volume or fixed depression + + + align:start position:0% +fixed volume or fixed depression +we haven't really gotten there yet but + + align:start position:0% +we haven't really gotten there yet but + + + align:start position:0% +we haven't really gotten there yet but +I'm wondering if somebody wants to + + align:start position:0% +I'm wondering if somebody wants to + + + align:start position:0% +I'm wondering if somebody wants to +Venture a guess with an explanation + + align:start position:0% + + + + align:start position:0% + +uh maybe fixed pressure + + align:start position:0% +uh maybe fixed pressure + + + align:start position:0% +uh maybe fixed pressure +expression how do you figure uh I mean I + + align:start position:0% +expression how do you figure uh I mean I + + + align:start position:0% +expression how do you figure uh I mean I +think like if the system is like half + + align:start position:0% +think like if the system is like half + + + align:start position:0% +think like if the system is like half +fixed volume it would wouldn't be able + + align:start position:0% +fixed volume it would wouldn't be able + + + align:start position:0% +fixed volume it would wouldn't be able +to use the heat as well + + align:start position:0% +to use the heat as well + + + align:start position:0% +to use the heat as well +but to fix pressure that can expand + + align:start position:0% +but to fix pressure that can expand + + + align:start position:0% +but to fix pressure that can expand +yeah so so your reasoning is right but + + align:start position:0% +yeah so so your reasoning is right but + + + align:start position:0% +yeah so so your reasoning is right but +your answer is wrong so I'm glad the + + align:start position:0% +your answer is wrong so I'm glad the + + + align:start position:0% +your answer is wrong so I'm glad the +reason there is when when you have a + + align:start position:0% +reason there is when when you have a + + + align:start position:0% +reason there is when when you have a +system that's a fixed volume it can't do + + align:start position:0% +system that's a fixed volume it can't do + + + align:start position:0% +system that's a fixed volume it can't do +any work on the surroundings right it's + + align:start position:0% +any work on the surroundings right it's + + + align:start position:0% +any work on the surroundings right it's +hemmed in + + align:start position:0% +hemmed in + + + align:start position:0% +hemmed in +so all the thermal energy you put in + + align:start position:0% +so all the thermal energy you put in + + + align:start position:0% +so all the thermal energy you put in +will go into a change in the internal + + align:start position:0% +will go into a change in the internal + + + align:start position:0% +will go into a change in the internal +energy of the system increase in + + align:start position:0% +energy of the system increase in + + + align:start position:0% +energy of the system increase in +temperature + + align:start position:0% +temperature + + + align:start position:0% +temperature +whereas if you have a system that's + + align:start position:0% +whereas if you have a system that's + + + align:start position:0% +whereas if you have a system that's +fixed pressure + + align:start position:0% +fixed pressure + + + align:start position:0% +fixed pressure +it can do work it can expand against its + + align:start position:0% +it can do work it can expand against its + + + align:start position:0% +it can do work it can expand against its +surroundings + + align:start position:0% +surroundings + + + align:start position:0% +surroundings +so as you pour energy in in the form of + + align:start position:0% +so as you pour energy in in the form of + + + align:start position:0% +so as you pour energy in in the form of +heat + + align:start position:0% +heat + + + align:start position:0% +heat +it can lose energy in the form of doing + + align:start position:0% +it can lose energy in the form of doing + + + align:start position:0% +it can lose energy in the form of doing +work + + align:start position:0% +work + + + align:start position:0% +work +so it's like filling up a leaky Cup + + align:start position:0% +so it's like filling up a leaky Cup + + + align:start position:0% +so it's like filling up a leaky Cup +right you have to pour more water in + + align:start position:0% +right you have to pour more water in + + + align:start position:0% +right you have to pour more water in +because there's stuff leaking out the + + align:start position:0% +because there's stuff leaking out the + + + align:start position:0% +because there's stuff leaking out the +bottom of the cup in this case the stuff + + align:start position:0% +bottom of the cup in this case the stuff + + + align:start position:0% +bottom of the cup in this case the stuff +leaking out is energy in the form of + + align:start position:0% +leaking out is energy in the form of + + + align:start position:0% +leaking out is energy in the form of +work on the surroundings + + align:start position:0% +work on the surroundings + + + align:start position:0% +work on the surroundings +so CV is is is smaller CP is larger but + + align:start position:0% +so CV is is is smaller CP is larger but + + + align:start position:0% +so CV is is is smaller CP is larger but +you're you're thinking about work was + + align:start position:0% +you're you're thinking about work was + + + align:start position:0% +you're you're thinking about work was +correct okay + + align:start position:0% + + + + align:start position:0% + +all right C + + align:start position:0% +all right C + + + align:start position:0% +all right C +is an empirical + + align:start position:0% + + + + align:start position:0% + +observable + + align:start position:0% + + + + align:start position:0% + +recorded in databases + + align:start position:0% + + + + align:start position:0% + +that's really important maybe you know + + align:start position:0% +that's really important maybe you know + + + align:start position:0% +that's really important maybe you know +that maybe you don't but the heat + + align:start position:0% +that maybe you don't but the heat + + + align:start position:0% +that maybe you don't but the heat +capacity of a system + + align:start position:0% +capacity of a system + + + align:start position:0% +capacity of a system +um tells you so much about that system + + align:start position:0% +um tells you so much about that system + + + align:start position:0% +um tells you so much about that system +but most of those things you can't + + align:start position:0% +but most of those things you can't + + + align:start position:0% +but most of those things you can't +calculate from first principles + + align:start position:0% +calculate from first principles + + + align:start position:0% +calculate from first principles +we need to be measured and then reported + + align:start position:0% +we need to be measured and then reported + + + align:start position:0% +we need to be measured and then reported +so for example + + align:start position:0% +so for example + + + align:start position:0% +so for example +what has larger + + align:start position:0% + + + + align:start position:0% + +right here's some okay here's + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +okay entry level what has a bigger heat + + align:start position:0% +okay entry level what has a bigger heat + + + align:start position:0% +okay entry level what has a bigger heat +capacity a big pot of water or a small + + align:start position:0% +capacity a big pot of water or a small + + + align:start position:0% +capacity a big pot of water or a small +pot of water + + align:start position:0% + + + + align:start position:0% + +you have the same + + align:start position:0% +you have the same + + + align:start position:0% +you have the same +well yeah it depends Your Capacity could + + align:start position:0% +well yeah it depends Your Capacity could + + + align:start position:0% +well yeah it depends Your Capacity could +be extensive or intensive + + align:start position:0% +be extensive or intensive + + + align:start position:0% +be extensive or intensive +right so I think I I know what you're + + align:start position:0% +right so I think I I know what you're + + + align:start position:0% +right so I think I I know what you're +saying water is water but when we want + + align:start position:0% +saying water is water but when we want + + + align:start position:0% +saying water is water but when we want +to regulate the temperature of something + + align:start position:0% +to regulate the temperature of something + + + align:start position:0% +to regulate the temperature of something +we want to prevent a temperature change + + align:start position:0% +we want to prevent a temperature change + + + align:start position:0% +we want to prevent a temperature change +it helps to have a large heat capacity + + align:start position:0% +it helps to have a large heat capacity + + + align:start position:0% +it helps to have a large heat capacity +object nearby + + align:start position:0% + + + + align:start position:0% + +a large thermal Reservoir + + align:start position:0% +a large thermal Reservoir + + + align:start position:0% +a large thermal Reservoir +that's one reasons why the temperatures + + align:start position:0% +that's one reasons why the temperatures + + + align:start position:0% +that's one reasons why the temperatures +are more moderate on the coasts of + + align:start position:0% +are more moderate on the coasts of + + + align:start position:0% +are more moderate on the coasts of +continents than Inland right our + + align:start position:0% +continents than Inland right our + + + align:start position:0% +continents than Inland right our +temperature in Boston doesn't swing + + align:start position:0% +temperature in Boston doesn't swing + + + align:start position:0% +temperature in Boston doesn't swing +nearly as much as it does in Iowa + + align:start position:0% +nearly as much as it does in Iowa + + + align:start position:0% +nearly as much as it does in Iowa +um you could say the same about any + + align:start position:0% +um you could say the same about any + + + align:start position:0% +um you could say the same about any +Inland versus Coastal Community in the + + align:start position:0% +Inland versus Coastal Community in the + + + align:start position:0% +Inland versus Coastal Community in the +world and the reason is that the oceans + + align:start position:0% +world and the reason is that the oceans + + + align:start position:0% +world and the reason is that the oceans +are a big thermal Reservoir they have a + + align:start position:0% +are a big thermal Reservoir they have a + + + align:start position:0% +are a big thermal Reservoir they have a +larger heat capacity than the Great + + align:start position:0% +larger heat capacity than the Great + + + align:start position:0% +larger heat capacity than the Great +Lakes do + + align:start position:0% +Lakes do + + + align:start position:0% +Lakes do +so our temperature swings are less okay + + align:start position:0% +so our temperature swings are less okay + + + align:start position:0% +so our temperature swings are less okay +what about bread + + align:start position:0% +what about bread + + + align:start position:0% +what about bread +or cheese + + align:start position:0% + + + + align:start position:0% + +same same quantity now same mess bread + + align:start position:0% +same same quantity now same mess bread + + + align:start position:0% +same same quantity now same mess bread +or cheese + + align:start position:0% + + + + align:start position:0% + +bread + + align:start position:0% +bread + + + align:start position:0% +bread +cheese I think it's cheese when you eat + + align:start position:0% +cheese I think it's cheese when you eat + + + align:start position:0% +cheese I think it's cheese when you eat +pizza the bread's not the one that burns + + align:start position:0% +pizza the bread's not the one that burns + + + align:start position:0% +pizza the bread's not the one that burns +the top of your mouth it's the cheese it + + align:start position:0% +the top of your mouth it's the cheese it + + + align:start position:0% +the top of your mouth it's the cheese it +has a larger heat capacity + + align:start position:0% +has a larger heat capacity + + + align:start position:0% +has a larger heat capacity +cheese has a large degree capacity it + + align:start position:0% +cheese has a large degree capacity it + + + align:start position:0% +cheese has a large degree capacity it +has to do with of course the chemistry + + align:start position:0% +has to do with of course the chemistry + + + align:start position:0% +has to do with of course the chemistry +big pot of water has a larger heat + + align:start position:0% +big pot of water has a larger heat + + + align:start position:0% +big pot of water has a larger heat +capacity what about aluminum foil or a + + align:start position:0% +capacity what about aluminum foil or a + + + align:start position:0% +capacity what about aluminum foil or a +potato + + align:start position:0% + + + + align:start position:0% + +all right sorry isn't + + align:start position:0% +all right sorry isn't + + + align:start position:0% +all right sorry isn't +isn't a larger heat capacity and ability + + align:start position:0% +isn't a larger heat capacity and ability + + + align:start position:0% +isn't a larger heat capacity and ability +to absorb more thermal energy without + + align:start position:0% +to absorb more thermal energy without + + + align:start position:0% +to absorb more thermal energy without +changing temperature though yes exactly + + align:start position:0% +changing temperature though yes exactly + + + align:start position:0% +changing temperature though yes exactly +so + + align:start position:0% +so + + + align:start position:0% +so +so isn't the isn't the cheese like + + align:start position:0% +so isn't the isn't the cheese like + + + align:start position:0% +so isn't the isn't the cheese like +changing more in temperature than the + + align:start position:0% +changing more in temperature than the + + + align:start position:0% +changing more in temperature than the +bread no what it means is that you have + + align:start position:0% +bread no what it means is that you have + + + align:start position:0% +bread no what it means is that you have +to put in more energy from your mouth to + + align:start position:0% +to put in more energy from your mouth to + + + align:start position:0% +to put in more energy from your mouth to +cool down the cheese than you do to cool + + align:start position:0% +cool down the cheese than you do to cool + + + align:start position:0% +cool down the cheese than you do to cool +down the bread + + align:start position:0% +down the bread + + + align:start position:0% +down the bread +so here's another example which should + + align:start position:0% +so here's another example which should + + + align:start position:0% +so here's another example which should +help aluminum foil versus potato you + + align:start position:0% +help aluminum foil versus potato you + + + align:start position:0% +help aluminum foil versus potato you +bake a potato that's wrapped in foil + + align:start position:0% + + + + align:start position:0% + +potato + + align:start position:0% +potato + + + align:start position:0% +potato +you take it out of the oven + + align:start position:0% + + + + align:start position:0% + +someone said potato the answer is going + + align:start position:0% +someone said potato the answer is going + + + align:start position:0% +someone said potato the answer is going +to be the foil when you take something + + align:start position:0% +to be the foil when you take something + + + align:start position:0% +to be the foil when you take something +out of the oven it's wrapped in foil you + + align:start position:0% +out of the oven it's wrapped in foil you + + + align:start position:0% +out of the oven it's wrapped in foil you +can often open the foil even if the oven + + align:start position:0% +can often open the foil even if the oven + + + align:start position:0% +can often open the foil even if the oven +was at 400 degrees you can you can open + + align:start position:0% +was at 400 degrees you can you can open + + + align:start position:0% +was at 400 degrees you can you can open +the foil without burning your fingers + + align:start position:0% +the foil without burning your fingers + + + align:start position:0% +the foil without burning your fingers +you have to avoid the steam right but + + align:start position:0% +you have to avoid the steam right but + + + align:start position:0% +you have to avoid the steam right but +you could you could grab that foil and + + align:start position:0% +you could you could grab that foil and + + + align:start position:0% +you could you could grab that foil and +very quickly bring that foil down to + + align:start position:0% +very quickly bring that foil down to + + + align:start position:0% +very quickly bring that foil down to +room temperature + + align:start position:0% +room temperature + + + align:start position:0% +room temperature +without burning your fingers + + align:start position:0% +without burning your fingers + + + align:start position:0% +without burning your fingers +but if you grab the potato you're gonna + + align:start position:0% +but if you grab the potato you're gonna + + + align:start position:0% +but if you grab the potato you're gonna +burn your hands because it takes more + + align:start position:0% +burn your hands because it takes more + + + align:start position:0% +burn your hands because it takes more +energy out of you in this case to cool + + align:start position:0% +energy out of you in this case to cool + + + align:start position:0% +energy out of you in this case to cool +the potato than it does to cool the soil + + align:start position:0% +the potato than it does to cool the soil + + + align:start position:0% +the potato than it does to cool the soil +doesn't that mean the potato is actually + + align:start position:0% +doesn't that mean the potato is actually + + + align:start position:0% +doesn't that mean the potato is actually +the one with high seeds + + align:start position:0% +the one with high seeds + + + align:start position:0% +the one with high seeds +uh larger c yeah sorry sorry yeah + + align:start position:0% +uh larger c yeah sorry sorry yeah + + + align:start position:0% +uh larger c yeah sorry sorry yeah +everything I said but reverse right + + align:start position:0% +everything I said but reverse right + + + align:start position:0% +everything I said but reverse right +exactly it's easier to bring down + + align:start position:0% +exactly it's easier to bring down + + + align:start position:0% +exactly it's easier to bring down +all right and this is lots of examples + + align:start position:0% +all right and this is lots of examples + + + align:start position:0% +all right and this is lots of examples +here that are every day right why + + align:start position:0% +here that are every day right why + + + align:start position:0% +here that are every day right why +certain surfaces outside feel colder or + + align:start position:0% +certain surfaces outside feel colder or + + + align:start position:0% +certain surfaces outside feel colder or +hotter than other surfaces on a very + + align:start position:0% +hotter than other surfaces on a very + + + align:start position:0% +hotter than other surfaces on a very +cold or a very hot day lots of examples + + align:start position:0% +cold or a very hot day lots of examples + + + align:start position:0% +cold or a very hot day lots of examples +like this okay + + align:start position:0% +like this okay + + + align:start position:0% +like this okay +so um so uh uh + + align:start position:0% +so um so uh uh + + + align:start position:0% +so um so uh uh +what do I mean to say here um + + align:start position:0% + + + + align:start position:0% + +C can be calculated + + align:start position:0% + + + + align:start position:0% + +for simple + + align:start position:0% +for simple + + + align:start position:0% +for simple +we call toy problems + + align:start position:0% + + + + align:start position:0% + +but in most cases + + align:start position:0% + + + + align:start position:0% + +especially cases that we rely on as + + align:start position:0% +especially cases that we rely on as + + + align:start position:0% +especially cases that we rely on as +engineers + + align:start position:0% +engineers + + + align:start position:0% +engineers +um + + align:start position:0% +um + + + align:start position:0% +um +measurements are necessary + + align:start position:0% + + + + align:start position:0% + +and I actually did record some numbers + + align:start position:0% +and I actually did record some numbers + + + align:start position:0% +and I actually did record some numbers +here so heat capacity in joules per gram + + align:start position:0% +here so heat capacity in joules per gram + + + align:start position:0% +here so heat capacity in joules per gram +Kelvin + + align:start position:0% +Kelvin + + + align:start position:0% +Kelvin +let's say water + + align:start position:0% +let's say water + + + align:start position:0% +let's say water +has a large heat capacity + + align:start position:0% +has a large heat capacity + + + align:start position:0% +has a large heat capacity +has to do with all of the vibrational + + align:start position:0% +has to do with all of the vibrational + + + align:start position:0% +has to do with all of the vibrational +degrees of freedom and water + + align:start position:0% +degrees of freedom and water + + + align:start position:0% +degrees of freedom and water +aluminum is very small 0.897 + + align:start position:0% +aluminum is very small 0.897 + + + align:start position:0% +aluminum is very small 0.897 +so this right here is why you can touch + + align:start position:0% +so this right here is why you can touch + + + align:start position:0% +so this right here is why you can touch +the aluminum foil but you have to avoid + + align:start position:0% +the aluminum foil but you have to avoid + + + align:start position:0% +the aluminum foil but you have to avoid +getting a steam burn + + align:start position:0% +getting a steam burn + + + align:start position:0% +getting a steam burn +right when you open up the food you've + + align:start position:0% +right when you open up the food you've + + + align:start position:0% +right when you open up the food you've +you've packed and foil potatoes actually + + align:start position:0% +you've packed and foil potatoes actually + + + align:start position:0% +you've packed and foil potatoes actually +uh + + align:start position:0% +uh + + + align:start position:0% +uh +large it's close to water + + align:start position:0% +large it's close to water + + + align:start position:0% +large it's close to water +because anything that's food related + + align:start position:0% +because anything that's food related + + + align:start position:0% +because anything that's food related +basically is set by the water content + + align:start position:0% +basically is set by the water content + + + align:start position:0% +basically is set by the water content +all right cheese + + align:start position:0% +all right cheese + + + align:start position:0% +all right cheese +has a lower water content than potato I + + align:start position:0% +has a lower water content than potato I + + + align:start position:0% +has a lower water content than potato I +grabbed the number 3.15 if you are a + + align:start position:0% +grabbed the number 3.15 if you are a + + + align:start position:0% +grabbed the number 3.15 if you are a +Gourmet Chef you have a table of heat + + align:start position:0% +Gourmet Chef you have a table of heat + + + align:start position:0% +Gourmet Chef you have a table of heat +capacities of things like cheese + + align:start position:0% +capacities of things like cheese + + + align:start position:0% +capacities of things like cheese +and um and uh and and 2.15 is just one + + align:start position:0% +and um and uh and and 2.15 is just one + + + align:start position:0% +and um and uh and and 2.15 is just one +number right I mean that's I don't know + + align:start position:0% +number right I mean that's I don't know + + + align:start position:0% +number right I mean that's I don't know +Cheddars but anyway + + align:start position:0% +Cheddars but anyway + + + align:start position:0% +Cheddars but anyway +um + + align:start position:0% +um + + + align:start position:0% +um +so let's move on + + align:start position:0% +so let's move on + + + align:start position:0% +so let's move on +let's move on + + align:start position:0% + + + + align:start position:0% + +so let's talk about something really + + align:start position:0% +so let's talk about something really + + + align:start position:0% +so let's talk about something really +important + + align:start position:0% +important + + + align:start position:0% +important +the first law of thermodynamics + + align:start position:0% + + + + align:start position:0% + +okay so here's the first law of thumb + + align:start position:0% +okay so here's the first law of thumb + + + align:start position:0% +okay so here's the first law of thumb +Dynamics + + align:start position:0% + + + + align:start position:0% + +as + + align:start position:0% +as + + + align:start position:0% +as +you sometimes encounter it in a physics + + align:start position:0% +you sometimes encounter it in a physics + + + align:start position:0% +you sometimes encounter it in a physics +class + + align:start position:0% + + + + align:start position:0% + +and I'm here to tell you this is totally + + align:start position:0% +and I'm here to tell you this is totally + + + align:start position:0% +and I'm here to tell you this is totally +useless + + align:start position:0% +useless + + + align:start position:0% +useless +because if this is all it were + + align:start position:0% +because if this is all it were + + + align:start position:0% +because if this is all it were +who cares I mean it's interesting right + + align:start position:0% +who cares I mean it's interesting right + + + align:start position:0% +who cares I mean it's interesting right +but you can't use that + + align:start position:0% + + + + align:start position:0% + +and that's not how we arrived at it + + align:start position:0% +and that's not how we arrived at it + + + align:start position:0% +and that's not how we arrived at it +intellectually it's sort of + + align:start position:0% +intellectually it's sort of + + + align:start position:0% +intellectually it's sort of +intellectually + + align:start position:0% +intellectually + + + align:start position:0% +intellectually +um being dishonest + + align:start position:0% +um being dishonest + + + align:start position:0% +um being dishonest +because this is very non-obvious right + + align:start position:0% +because this is very non-obvious right + + + align:start position:0% +because this is very non-obvious right +it's very non-obvious and rather hard to + + align:start position:0% +it's very non-obvious and rather hard to + + + align:start position:0% +it's very non-obvious and rather hard to +prove also + + align:start position:0% +prove also + + + align:start position:0% +prove also +how is this useful + + align:start position:0% + + + + align:start position:0% + +the answer + + align:start position:0% +the answer + + + align:start position:0% +the answer +is because it applies locally + + align:start position:0% +is because it applies locally + + + align:start position:0% +is because it applies locally +and this is where the real intellectual + + align:start position:0% +and this is where the real intellectual + + + align:start position:0% +and this is where the real intellectual +thread comes from + + align:start position:0% + + + + align:start position:0% + +so we talk about the energy + + align:start position:0% + + + + align:start position:0% + +of a system + + align:start position:0% + + + + align:start position:0% + +plus the surroundings + + align:start position:0% + + + + align:start position:0% + +system plus surroundings + + align:start position:0% +system plus surroundings + + + align:start position:0% +system plus surroundings +you could call universe + + align:start position:0% + + + + align:start position:0% + +it's kind of highfalutin language + + align:start position:0% +it's kind of highfalutin language + + + align:start position:0% +it's kind of highfalutin language +sometimes I'll flip and I'll say + + align:start position:0% +sometimes I'll flip and I'll say + + + align:start position:0% +sometimes I'll flip and I'll say +universe but I don't mean to systems for + + align:start position:0% +universe but I don't mean to systems for + + + align:start position:0% +universe but I don't mean to systems for +surroundings energy this isn't for + + align:start position:0% +surroundings energy this isn't for + + + align:start position:0% +surroundings energy this isn't for +surroundings is constant + + align:start position:0% + + + + align:start position:0% + +but here's where it gets useful + + align:start position:0% +but here's where it gets useful + + + align:start position:0% +but here's where it gets useful +we use + + align:start position:0% +we use + + + align:start position:0% +we use +the boundary + + align:start position:0% + + + + align:start position:0% + +for bookkeeping + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% +and + + + align:start position:0% +and +like it or not a lot of thermo is + + align:start position:0% +like it or not a lot of thermo is + + + align:start position:0% +like it or not a lot of thermo is +bookkeeping + + align:start position:0% + + + + align:start position:0% + +right so we have a system + + align:start position:0% +right so we have a system + + + align:start position:0% +right so we have a system +we have a boundary + + align:start position:0% + + + + align:start position:0% + +and we have + + align:start position:0% +and we have + + + align:start position:0% +and we have +flows of energy + + align:start position:0% +flows of energy + + + align:start position:0% +flows of energy +and we can keep track of them and we can + + align:start position:0% +and we can keep track of them and we can + + + align:start position:0% +and we can keep track of them and we can +keep track of the forms that energy can + + align:start position:0% +keep track of the forms that energy can + + + align:start position:0% +keep track of the forms that energy can +flow so there are three ways that energy + + align:start position:0% +flow so there are three ways that energy + + + align:start position:0% +flow so there are three ways that energy +can flow between a system and the + + align:start position:0% +can flow between a system and the + + + align:start position:0% +can flow between a system and the +surroundings in 3020 + + align:start position:0% +surroundings in 3020 + + + align:start position:0% +surroundings in 3020 +we've encountered two of them so far uh + + align:start position:0% +we've encountered two of them so far uh + + + align:start position:0% +we've encountered two of them so far uh +about 20 minutes ago if somebody want to + + align:start position:0% +about 20 minutes ago if somebody want to + + + align:start position:0% +about 20 minutes ago if somebody want to +tell me what the three of them are all + + align:start position:0% +tell me what the three of them are all + + + align:start position:0% +tell me what the three of them are all +three + + align:start position:0% + + + + align:start position:0% + +action radiation and conduction + + align:start position:0% +action radiation and conduction + + + align:start position:0% +action radiation and conduction +nope sorry + + align:start position:0% +nope sorry + + + align:start position:0% +nope sorry +so those are those are forms of heat + + align:start position:0% +so those are those are forms of heat + + + align:start position:0% +so those are those are forms of heat +transfer + + align:start position:0% +transfer + + + align:start position:0% +transfer +but um + + align:start position:0% +but um + + + align:start position:0% +but um +we are not going to talk about fluid + + align:start position:0% +we are not going to talk about fluid + + + align:start position:0% +we are not going to talk about fluid +dynamics or uh or radiative processes in + + align:start position:0% +dynamics or uh or radiative processes in + + + align:start position:0% +dynamics or uh or radiative processes in +any detail in o2o so what you said was + + align:start position:0% +any detail in o2o so what you said was + + + align:start position:0% +any detail in o2o so what you said was +scientifically true it's it's not + + align:start position:0% +scientifically true it's it's not + + + align:start position:0% +scientifically true it's it's not +specifically what the three forms are in + + align:start position:0% +specifically what the three forms are in + + + align:start position:0% +specifically what the three forms are in +O2L we've talked about two of them so + + align:start position:0% +O2L we've talked about two of them so + + + align:start position:0% +O2L we've talked about two of them so +far + + align:start position:0% +far + + + align:start position:0% +far +um one is heat which is everything you + + align:start position:0% +um one is heat which is everything you + + + align:start position:0% +um one is heat which is everything you +just described + + align:start position:0% +just described + + + align:start position:0% +just described +what's another way energy can flow + + align:start position:0% + + + + align:start position:0% + +work work okay cool he he works + + align:start position:0% +work work okay cool he he works + + + align:start position:0% +work work okay cool he he works +mechanical work and there's a third way + + align:start position:0% +mechanical work and there's a third way + + + align:start position:0% +mechanical work and there's a third way +that energy can can flow that we haven't + + align:start position:0% +that energy can can flow that we haven't + + + align:start position:0% +that energy can can flow that we haven't +introduced it yet would anyone like to + + align:start position:0% +introduced it yet would anyone like to + + + align:start position:0% +introduced it yet would anyone like to +venture our guests Mass transfer Mass + + align:start position:0% +venture our guests Mass transfer Mass + + + align:start position:0% +venture our guests Mass transfer Mass +transfer right matter has energy and so + + align:start position:0% +transfer right matter has energy and so + + + align:start position:0% +transfer right matter has energy and so +you can exchange matter + + align:start position:0% +you can exchange matter + + + align:start position:0% +you can exchange matter +and transfer energy that way so this is + + align:start position:0% +and transfer energy that way so this is + + + align:start position:0% +and transfer energy that way so this is +the bookkeeping that we're going to do + + align:start position:0% +the bookkeeping that we're going to do + + + align:start position:0% +the bookkeeping that we're going to do +in this class so this gets me to + + align:start position:0% +in this class so this gets me to + + + align:start position:0% +in this class so this gets me to +first law bookkeeper + + align:start position:0% + + + + align:start position:0% + +I wish I had a week to teach the fluid + + align:start position:0% +I wish I had a week to teach the fluid + + + align:start position:0% +I wish I had a week to teach the fluid +dynamics and talk about + + align:start position:0% +dynamics and talk about + + + align:start position:0% +dynamics and talk about +convection and then talk about heat + + align:start position:0% +convection and then talk about heat + + + align:start position:0% +convection and then talk about heat +transfer talk about conduction and do + + align:start position:0% +transfer talk about conduction and do + + + align:start position:0% +transfer talk about conduction and do +radiative but um it goes well beyond + + align:start position:0% +radiative but um it goes well beyond + + + align:start position:0% +radiative but um it goes well beyond +this class + + align:start position:0% +this class + + + align:start position:0% +this class +you'll learn about those things in other + + align:start position:0% +you'll learn about those things in other + + + align:start position:0% +you'll learn about those things in other +classes or come to office hours we can + + align:start position:0% +classes or come to office hours we can + + + align:start position:0% +classes or come to office hours we can +talk about heat transfer first law + + align:start position:0% +talk about heat transfer first law + + + align:start position:0% +talk about heat transfer first law +bookkeeping okay this is where we + + align:start position:0% +bookkeeping okay this is where we + + + align:start position:0% +bookkeeping okay this is where we +hopefully + + align:start position:0% +hopefully + + + align:start position:0% +hopefully +resolve some ambiguity about o2o via V + + align:start position:0% +resolve some ambiguity about o2o via V + + + align:start position:0% +resolve some ambiguity about o2o via V +other classes you've taken so types of + + align:start position:0% +other classes you've taken so types of + + + align:start position:0% +other classes you've taken so types of +energy + + align:start position:0% +energy + + + align:start position:0% +energy +include kinetic + + align:start position:0% + + + + align:start position:0% + +potential + + align:start position:0% + + + + align:start position:0% + +and internal + + align:start position:0% + + + + align:start position:0% + +which we use U + + align:start position:0% +which we use U + + + align:start position:0% +which we use U +so kinetic energy depends on how fast + + align:start position:0% +so kinetic energy depends on how fast + + + align:start position:0% +so kinetic energy depends on how fast +a system is moving right you know that + + align:start position:0% +a system is moving right you know that + + + align:start position:0% +a system is moving right you know that +so if your system is a baseball + + align:start position:0% +so if your system is a baseball + + + align:start position:0% +so if your system is a baseball +kinetic energy is how fast it's moving + + align:start position:0% +kinetic energy is how fast it's moving + + + align:start position:0% +kinetic energy is how fast it's moving +potential energy + + align:start position:0% + + + + align:start position:0% + +depends on where a system is + + align:start position:0% +depends on where a system is + + + align:start position:0% +depends on where a system is +in some reference frame so again if your + + align:start position:0% +in some reference frame so again if your + + + align:start position:0% +in some reference frame so again if your +system is a baseball the potential + + align:start position:0% +system is a baseball the potential + + + align:start position:0% +system is a baseball the potential +energy depends on where it is relative + + align:start position:0% +energy depends on where it is relative + + + align:start position:0% +energy depends on where it is relative +to the center of mass of the Earth + + align:start position:0% + + + + align:start position:0% + +internal energy is everything else + + align:start position:0% +internal energy is everything else + + + align:start position:0% +internal energy is everything else +all of the energy which is independent + + align:start position:0% +all of the energy which is independent + + + align:start position:0% +all of the energy which is independent +of the velocity of the system and + + align:start position:0% +of the velocity of the system and + + + align:start position:0% +of the velocity of the system and +independent of the location of the + + align:start position:0% +independent of the location of the + + + align:start position:0% +independent of the location of the +system so again if your system is the + + align:start position:0% +system so again if your system is the + + + align:start position:0% +system so again if your system is the +baseball the internal energy is all the + + align:start position:0% +baseball the internal energy is all the + + + align:start position:0% +baseball the internal energy is all the +molecular bonds that make up the + + align:start position:0% +molecular bonds that make up the + + + align:start position:0% +molecular bonds that make up the +baseball + + align:start position:0% + + + + align:start position:0% + +plus The Binding energy of the electrons + + align:start position:0% +plus The Binding energy of the electrons + + + align:start position:0% +plus The Binding energy of the electrons +to the nuclei okay so this is the one + + align:start position:0% +to the nuclei okay so this is the one + + + align:start position:0% +to the nuclei okay so this is the one +that we use in thermal + + align:start position:0% +that we use in thermal + + + align:start position:0% +that we use in thermal +this is the last time we'll talk about + + align:start position:0% +this is the last time we'll talk about + + + align:start position:0% +this is the last time we'll talk about +kinetic energy and the last time we'll + + align:start position:0% +kinetic energy and the last time we'll + + + align:start position:0% +kinetic energy and the last time we'll +talk about potential energy we might get + + align:start position:0% +talk about potential energy we might get + + + align:start position:0% +talk about potential energy we might get +to like 20 minutes of electrochemistry + + align:start position:0% +to like 20 minutes of electrochemistry + + + align:start position:0% +to like 20 minutes of electrochemistry +later in the term and then potential + + align:start position:0% +later in the term and then potential + + + align:start position:0% +later in the term and then potential +might sneak back in but basically this + + align:start position:0% +might sneak back in but basically this + + + align:start position:0% +might sneak back in but basically this +is where we are for + + align:start position:0% + + + + align:start position:0% + +3020 okay what about processes + + align:start position:0% +3020 okay what about processes + + + align:start position:0% +3020 okay what about processes +please + + align:start position:0% + + + + align:start position:0% + +processes that exchange energy so this + + align:start position:0% +processes that exchange energy so this + + + align:start position:0% +processes that exchange energy so this +week we just answer there's Heating + + align:start position:0% + + + + align:start position:0% + +there's work + + align:start position:0% + + + + align:start position:0% + +and there's Mass transfer + + align:start position:0% + + + + align:start position:0% + +okay so this is some first lot + + align:start position:0% +okay so this is some first lot + + + align:start position:0% +okay so this is some first lot +bookkeeping I hope this helps a little + + align:start position:0% +bookkeeping I hope this helps a little + + + align:start position:0% +bookkeeping I hope this helps a little +bit + + align:start position:0% +bit + + + align:start position:0% +bit +um + + align:start position:0% +um + + + align:start position:0% +um +as we try to recall what what counts and + + align:start position:0% +as we try to recall what what counts and + + + align:start position:0% +as we try to recall what what counts and +what doesn't an equilibrium Therma + + align:start position:0% + + + + align:start position:0% + +all right so so um + + align:start position:0% +all right so so um + + + align:start position:0% +all right so so um +we can do this mathematically + + align:start position:0% +we can do this mathematically + + + align:start position:0% +we can do this mathematically +energy is a state function but it's + + align:start position:0% +energy is a state function but it's + + + align:start position:0% +energy is a state function but it's +changed by processes + + align:start position:0% +changed by processes + + + align:start position:0% +changed by processes +so d u + + align:start position:0% +so d u + + + align:start position:0% +so d u +equals + + align:start position:0% + + + + align:start position:0% + +change in heat energy + + align:start position:0% + + + + align:start position:0% + +plus change and mechanical work + + align:start position:0% + + + + align:start position:0% + +plus something new + + align:start position:0% + + + + align:start position:0% + +a term which accounts for a change in + + align:start position:0% +a term which accounts for a change in + + + align:start position:0% +a term which accounts for a change in +mass + + align:start position:0% +mass + + + align:start position:0% +mass +thank you + + align:start position:0% +thank you + + + align:start position:0% +thank you +so d q equals heat + + align:start position:0% +so d q equals heat + + + align:start position:0% +so d q equals heat +applied + + align:start position:0% + + + + align:start position:0% + +to + + align:start position:0% +to + + + align:start position:0% +to +the system is a sign convention here + + align:start position:0% +the system is a sign convention here + + + align:start position:0% +the system is a sign convention here +we're going to follow the sign + + align:start position:0% +we're going to follow the sign + + + align:start position:0% +we're going to follow the sign +convention in the dahas textbook + + align:start position:0% + + + + align:start position:0% + +so if you're heating a system + + align:start position:0% +so if you're heating a system + + + align:start position:0% +so if you're heating a system +let's say that's the endothermic + + align:start position:0% +let's say that's the endothermic + + + align:start position:0% +let's say that's the endothermic +reaction the instant cold pack then DQ + + align:start position:0% +reaction the instant cold pack then DQ + + + align:start position:0% +reaction the instant cold pack then DQ +is positive right + + align:start position:0% +is positive right + + + align:start position:0% +is positive right +d w is work + + align:start position:0% + + + + align:start position:0% + +performed + + align:start position:0% + + + + align:start position:0% + +on + + align:start position:0% +on + + + align:start position:0% +on +the system + + align:start position:0% + + + + align:start position:0% + +so there's a consistent convention there + + align:start position:0% +so there's a consistent convention there + + + align:start position:0% +so there's a consistent convention there +these have the same sign + + align:start position:0% +these have the same sign + + + align:start position:0% +these have the same sign +right positive DQ increases the energy + + align:start position:0% +right positive DQ increases the energy + + + align:start position:0% +right positive DQ increases the energy +of the system positive DW increases the + + align:start position:0% +of the system positive DW increases the + + + align:start position:0% +of the system positive DW increases the +energy of the system + + align:start position:0% + + + + align:start position:0% + +so for example + + align:start position:0% + + + + align:start position:0% + +for mechanical work that we encounter in + + align:start position:0% +for mechanical work that we encounter in + + + align:start position:0% +for mechanical work that we encounter in +this class + + align:start position:0% +this class + + + align:start position:0% +this class +ew equals p + + align:start position:0% +ew equals p + + + align:start position:0% +ew equals p +DV + + align:start position:0% +DV + + + align:start position:0% +DV +and here I'll ask is it positive or + + align:start position:0% +and here I'll ask is it positive or + + + align:start position:0% +and here I'll ask is it positive or +minus + + align:start position:0% + + + + align:start position:0% + +which one is it + + align:start position:0% + + + + align:start position:0% + +this is the pressure this is the change + + align:start position:0% +this is the pressure this is the change + + + align:start position:0% +this is the pressure this is the change +in volume of a system + + align:start position:0% + + + + align:start position:0% + +so a positive pdv means the system is + + align:start position:0% +so a positive pdv means the system is + + + align:start position:0% +so a positive pdv means the system is +doing work on the surroundings it's + + align:start position:0% +doing work on the surroundings it's + + + align:start position:0% +doing work on the surroundings it's +expanding against the surroundings + + align:start position:0% +expanding against the surroundings + + + align:start position:0% +expanding against the surroundings +so what should be the sign here to stick + + align:start position:0% +so what should be the sign here to stick + + + align:start position:0% +so what should be the sign here to stick +with our new convention + + align:start position:0% +with our new convention + + + align:start position:0% +with our new convention +negative negative right it's negative + + align:start position:0% +negative negative right it's negative + + + align:start position:0% +negative negative right it's negative +because the system is losing energy + + align:start position:0% +because the system is losing energy + + + align:start position:0% +because the system is losing energy +as it expands right negative so it + + align:start position:0% +as it expands right negative so it + + + align:start position:0% +as it expands right negative so it +equals minus p + + align:start position:0% +equals minus p + + + align:start position:0% +equals minus p +DV + + align:start position:0% + + + + align:start position:0% + +a little mathematical note here this is + + align:start position:0% +a little mathematical note here this is + + + align:start position:0% +a little mathematical note here this is +a process + + align:start position:0% +a process + + + align:start position:0% +a process +variable + + align:start position:0% +variable + + + align:start position:0% +variable +right + + align:start position:0% +right + + + align:start position:0% +right +this is a state + + align:start position:0% +this is a state + + + align:start position:0% +this is a state +variable + + align:start position:0% + + + + align:start position:0% + +this is not an equation of State this is + + align:start position:0% +this is not an equation of State this is + + + align:start position:0% +this is not an equation of State this is +a differential form of an equation of + + align:start position:0% +a differential form of an equation of + + + align:start position:0% +a differential form of an equation of +state so it's not the same thing + + align:start position:0% +state so it's not the same thing + + + align:start position:0% +state so it's not the same thing +but it has this funny uh + + align:start position:0% +but it has this funny uh + + + align:start position:0% +but it has this funny uh +property that you have on the one hand + + align:start position:0% +property that you have on the one hand + + + align:start position:0% +property that you have on the one hand +process variable on the other hand of + + align:start position:0% +process variable on the other hand of + + + align:start position:0% +process variable on the other hand of +State variable this could be considered + + align:start position:0% + + + + align:start position:0% + +an integration constant + + align:start position:0% + + + + align:start position:0% + +if you don't care about that comment + + align:start position:0% +if you don't care about that comment + + + align:start position:0% +if you don't care about that comment +ignore that comment we don't really talk + + align:start position:0% +ignore that comment we don't really talk + + + align:start position:0% +ignore that comment we don't really talk +about integration constants in this + + align:start position:0% +about integration constants in this + + + align:start position:0% +about integration constants in this +class we don't have time but they are + + align:start position:0% +class we don't have time but they are + + + align:start position:0% +class we don't have time but they are +kind of hidden there in the structure of + + align:start position:0% +kind of hidden there in the structure of + + + align:start position:0% +kind of hidden there in the structure of +Therma + + align:start position:0% +Therma + + + align:start position:0% +Therma +all right so DQ DW + + align:start position:0% +all right so DQ DW + + + align:start position:0% +all right so DQ DW +and + + align:start position:0% + + + + align:start position:0% + +mu i d n i + + align:start position:0% +mu i d n i + + + align:start position:0% +mu i d n i +equals the energy + + align:start position:0% + + + + align:start position:0% + +of + + align:start position:0% +of + + + align:start position:0% +of +change + + align:start position:0% +change + + + align:start position:0% +change +D and I + + align:start position:0% +D and I + + + align:start position:0% +D and I +of moles + + align:start position:0% +of moles + + + align:start position:0% +of moles +of component I + + align:start position:0% + + + + align:start position:0% + +where I has to run over all the + + align:start position:0% +where I has to run over all the + + + align:start position:0% +where I has to run over all the +different components of the system so n + + align:start position:0% +different components of the system so n + + + align:start position:0% +different components of the system so n +of I equals number moles + + align:start position:0% + + + + align:start position:0% + +of component I + + align:start position:0% + + + + align:start position:0% + +and mu of I is defined as + + align:start position:0% +and mu of I is defined as + + + align:start position:0% +and mu of I is defined as +partial U + + align:start position:0% +partial U + + + align:start position:0% +partial U +partial n of I + + align:start position:0% +partial n of I + + + align:start position:0% +partial n of I +for fixed and we'll get to this entropy + + align:start position:0% +for fixed and we'll get to this entropy + + + align:start position:0% +for fixed and we'll get to this entropy +volume + + align:start position:0% +volume + + + align:start position:0% +volume +and moles of J not equal to I + + align:start position:0% + + + + align:start position:0% + +I is a component label + + align:start position:0% + + + + align:start position:0% + +and this whole thing is called the + + align:start position:0% +and this whole thing is called the + + + align:start position:0% +and this whole thing is called the +chemical potential + + align:start position:0% + + + + align:start position:0% + +which is a really Central concept for + + align:start position:0% +which is a really Central concept for + + + align:start position:0% +which is a really Central concept for +Material Science and chemical + + align:start position:0% +Material Science and chemical + + + align:start position:0% +Material Science and chemical +engineering + + align:start position:0% +engineering + + + align:start position:0% +engineering +so we will go spending + + align:start position:0% +so we will go spending + + + align:start position:0% +so we will go spending +an entire term on the chemical potential + + align:start position:0% +an entire term on the chemical potential + + + align:start position:0% +an entire term on the chemical potential +okay that's where I wanted to get to + + align:start position:0% +okay that's where I wanted to get to + + + align:start position:0% +okay that's where I wanted to get to +today \ No newline at end of file diff --git a/T2n6fVybLcU.txt b/T2n6fVybLcU.txt new file mode 100644 index 0000000000000000000000000000000000000000..201ab6b58928ebc3858b9aa9599c8d2226cda3bc --- /dev/null +++ b/T2n6fVybLcU.txt @@ -0,0 +1,9667 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT OpenCourseWare continue to + + align:start position:0% +will help MIT OpenCourseWare continue to + + + align:start position:0% +will help MIT OpenCourseWare continue to +offer high quality educational resources + + align:start position:0% +offer high quality educational resources + + + align:start position:0% +offer high quality educational resources +for free + + align:start position:0% +for free + + + align:start position:0% +for free +to make a donation or to view additional + + align:start position:0% +to make a donation or to view additional + + + align:start position:0% +to make a donation or to view additional +materials from hundreds of MIT courses + + align:start position:0% +materials from hundreds of MIT courses + + + align:start position:0% +materials from hundreds of MIT courses +visit MIT opencourseware at ocw.mit.edu + + align:start position:0% + + + + align:start position:0% + +okay so welcome back everybody we'll + + align:start position:0% +okay so welcome back everybody we'll + + + align:start position:0% +okay so welcome back everybody we'll +come back to a o3 today we are going to + + align:start position:0% +come back to a o3 today we are going to + + + align:start position:0% +come back to a o3 today we are going to +continue a discussion of the harmonic + + align:start position:0% +continue a discussion of the harmonic + + + align:start position:0% +continue a discussion of the harmonic +oscillators and also we will add 10 p.m. + + align:start position:0% +oscillators and also we will add 10 p.m. + + + align:start position:0% +oscillators and also we will add 10 p.m. +force into the game and see what will + + align:start position:0% +force into the game and see what will + + + align:start position:0% +force into the game and see what will +happen okay so this essentially what we + + align:start position:0% +happen okay so this essentially what we + + + align:start position:0% +happen okay so this essentially what we +have learned that time from this slide + + align:start position:0% +have learned that time from this slide + + + align:start position:0% +have learned that time from this slide +we have analyzed the physics of a + + align:start position:0% +we have analyzed the physics of a + + + align:start position:0% +we have analyzed the physics of a +harmonic oscillator so which we actually + + align:start position:0% +harmonic oscillator so which we actually + + + align:start position:0% +harmonic oscillator so which we actually +demonstrated last time and you can see + + align:start position:0% +demonstrated last time and you can see + + + align:start position:0% +demonstrated last time and you can see +the device still there and Hookes law + + align:start position:0% +the device still there and Hookes law + + + align:start position:0% +the device still there and Hookes law +actually Hookes law is actually far more + + align:start position:0% +actually Hookes law is actually far more + + + align:start position:0% +actually Hookes law is actually far more +general than what we saw before it works + + align:start position:0% +general than what we saw before it works + + + align:start position:0% +general than what we saw before it works +for all small oscillations run about a + + align:start position:0% +for all small oscillations run about a + + + align:start position:0% +for all small oscillations run about a +point of equilibrium position okay and + + align:start position:0% +point of equilibrium position okay and + + + align:start position:0% +point of equilibrium position okay and +that is it can be demonstrated by + + align:start position:0% +that is it can be demonstrated by + + + align:start position:0% +that is it can be demonstrated by +multiple different kind of physical + + align:start position:0% +multiple different kind of physical + + + align:start position:0% +multiple different kind of physical +systems for example here I have a mass + + align:start position:0% +systems for example here I have a mass + + + align:start position:0% +systems for example here I have a mass +which essentially can only move along + + align:start position:0% +which essentially can only move along + + + align:start position:0% +which essentially can only move along +this track here and if I put these maths + + align:start position:0% +this track here and if I put these maths + + + align:start position:0% +this track here and if I put these maths +set free and this thing is actually + + align:start position:0% +set free and this thing is actually + + + align:start position:0% +set free and this thing is actually +exercising harmonic oscillation okay we + + align:start position:0% +exercising harmonic oscillation okay we + + + align:start position:0% +exercising harmonic oscillation okay we +can do this with large amplitude with + + align:start position:0% +can do this with large amplitude with + + + align:start position:0% +can do this with large amplitude with +and also to it with small amplitude and + + align:start position:0% +and also to it with small amplitude and + + + align:start position:0% +and also to it with small amplitude and +you see that hi pretty it works + + align:start position:0% +you see that hi pretty it works + + + align:start position:0% +you see that hi pretty it works +Hookes law actually works and it + + align:start position:0% +Hookes law actually works and it + + + align:start position:0% +Hookes law actually works and it +predicts exactly the same motion as what + + align:start position:0% +predicts exactly the same motion as what + + + align:start position:0% +predicts exactly the same motion as what +you see on the slide okay and we also + + align:start position:0% +you see on the slide okay and we also + + + align:start position:0% +you see on the slide okay and we also +have a little bit more complicated + + align:start position:0% +have a little bit more complicated + + + align:start position:0% +have a little bit more complicated +system for example this is as your some + + align:start position:0% +system for example this is as your some + + + align:start position:0% +system for example this is as your some +kind of rod and you can actually fixed + + align:start position:0% +kind of rod and you can actually fixed + + + align:start position:0% +kind of rod and you can actually fixed +one point and make it oscillate and we + + align:start position:0% +one point and make it oscillate and we + + + align:start position:0% +one point and make it oscillate and we +see that ha he also does some kind of + + align:start position:0% +see that ha he also does some kind of + + + align:start position:0% +see that ha he also does some kind of +harmonic oscillation but now what is + + align:start position:0% +harmonic oscillation but now what is + + + align:start position:0% +harmonic oscillation but now what is +actually that oscillating is the + + align:start position:0% +actually that oscillating is the + + + align:start position:0% +actually that oscillating is the +amplitude the amplitude is actually the + + align:start position:0% +amplitude the amplitude is actually the + + + align:start position:0% +amplitude the amplitude is actually the +angle with respect to the to a downward + + align:start position:0% +angle with respect to the to a downward + + + align:start position:0% +angle with respect to the to a downward +direction and finally this is actually + + align:start position:0% +direction and finally this is actually + + + align:start position:0% +direction and finally this is actually +up the Lebert + + align:start position:0% +up the Lebert + + + align:start position:0% +up the Lebert +conversion of this spring-mass system + + align:start position:0% +conversion of this spring-mass system + + + align:start position:0% +conversion of this spring-mass system +which will be analyzing data yo your + + align:start position:0% +which will be analyzing data yo your + + + align:start position:0% +which will be analyzing data yo your +pset and you see that huh + + align:start position:0% +pset and you see that huh + + + align:start position:0% +pset and you see that huh +you actually also they up and down + + align:start position:0% +you actually also they up and down + + + align:start position:0% +you actually also they up and down +harmonically so that's all very nice and + + align:start position:0% +harmonically so that's all very nice and + + + align:start position:0% +harmonically so that's all very nice and +we also have learned one thing which is + + align:start position:0% +we also have learned one thing which is + + + align:start position:0% +we also have learned one thing which is +very very interesting is that complete a + + align:start position:0% +very very interesting is that complete a + + + align:start position:0% +very very interesting is that complete a +complex exponential is actually a pretty + + align:start position:0% +complex exponential is actually a pretty + + + align:start position:0% +complex exponential is actually a pretty +beautiful way to present the solution + + align:start position:0% +beautiful way to present the solution + + + align:start position:0% +beautiful way to present the solution +and you se it works also in describing + + align:start position:0% +and you se it works also in describing + + + align:start position:0% +and you se it works also in describing +the temped oscillators and we will we + + align:start position:0% +the temped oscillators and we will we + + + align:start position:0% +the temped oscillators and we will we +will see how it works in the lecture + + align:start position:0% +will see how it works in the lecture + + + align:start position:0% +will see how it works in the lecture +today I'd receive several questions + + align:start position:0% +today I'd receive several questions + + + align:start position:0% +today I'd receive several questions +during my office hour and and through + + align:start position:0% +during my office hour and and through + + + align:start position:0% +during my office hour and and through +email or Piazza there were some + + align:start position:0% +email or Piazza there were some + + + align:start position:0% +email or Piazza there were some +confusions about doing a Taylor + + align:start position:0% +confusions about doing a Taylor + + + align:start position:0% +confusions about doing a Taylor +expansion okay so in in the lecture last + + align:start position:0% +expansion okay so in in the lecture last + + + align:start position:0% +expansion okay so in in the lecture last +time the equilibrium position is at X + + align:start position:0% +time the equilibrium position is at X + + + align:start position:0% +time the equilibrium position is at X +equal to zero therefore I do Taylor + + align:start position:0% +equal to zero therefore I do Taylor + + + align:start position:0% +equal to zero therefore I do Taylor +expansion around 0 okay but in this case + + align:start position:0% +expansion around 0 okay but in this case + + + align:start position:0% +expansion around 0 okay but in this case +if the equilibrium position or the + + align:start position:0% +if the equilibrium position or the + + + align:start position:0% +if the equilibrium position or the +minimum of the potential is at X equal + + align:start position:0% +minimum of the potential is at X equal + + + align:start position:0% +minimum of the potential is at X equal +to L then what you need to do is to do a + + align:start position:0% +to L then what you need to do is to do a + + + align:start position:0% +to L then what you need to do is to do a +Taylor expansion around X equal to L + + align:start position:0% +Taylor expansion around X equal to L + + + align:start position:0% +Taylor expansion around X equal to L +okay just to make that really really + + align:start position:0% +okay just to make that really really + + + align:start position:0% +okay just to make that really really +clear + + align:start position:0% +clear + + + align:start position:0% +clear +okay okay I hope that will help you with + + align:start position:0% +okay okay I hope that will help you with + + + align:start position:0% +okay okay I hope that will help you with +the pset question okay so that's get + + align:start position:0% +the pset question okay so that's get + + + align:start position:0% +the pset question okay so that's get +started immediately so let's continue + + align:start position:0% +started immediately so let's continue + + + align:start position:0% +started immediately so let's continue +the discussion of the equation of motion + + align:start position:0% +the discussion of the equation of motion + + + align:start position:0% +the discussion of the equation of motion +we arrived last time so we have n X + + align:start position:0% +we arrived last time so we have n X + + + align:start position:0% +we arrived last time so we have n X +double dot and this is equal to minus K + + align:start position:0% +double dot and this is equal to minus K + + + align:start position:0% +double dot and this is equal to minus K +X okay that's this issue the formula + + align:start position:0% +X okay that's this issue the formula + + + align:start position:0% +X okay that's this issue the formula +from last time and we can actually + + align:start position:0% +from last time and we can actually + + + align:start position:0% +from last time and we can actually +calculate the kinetic energy + + align:start position:0% + + + + align:start position:0% + +of this spring-mass system and basically + + align:start position:0% +of this spring-mass system and basically + + + align:start position:0% +of this spring-mass system and basically +we will arrive this is going to be equal + + align:start position:0% +we will arrive this is going to be equal + + + align:start position:0% +we will arrive this is going to be equal +to 1 1 / 2 and times X dot square okay + + align:start position:0% +to 1 1 / 2 and times X dot square okay + + + align:start position:0% +to 1 1 / 2 and times X dot square okay +and we can also calculate the potential + + align:start position:0% +and we can also calculate the potential + + + align:start position:0% +and we can also calculate the potential +energy of with the of the spring + + align:start position:0% +energy of with the of the spring + + + align:start position:0% +energy of with the of the spring +potential energy and that is equal to + + align:start position:0% +potential energy and that is equal to + + + align:start position:0% +potential energy and that is equal to +1/2 K x squared we also know what would + + align:start position:0% +1/2 K x squared we also know what would + + + align:start position:0% +1/2 K x squared we also know what would +be the total energy the total energy + + align:start position:0% +be the total energy the total energy + + + align:start position:0% +be the total energy the total energy +will be a sum of the kinetic energy and + + align:start position:0% +will be a sum of the kinetic energy and + + + align:start position:0% +will be a sum of the kinetic energy and +the potential basically you get this + + align:start position:0% +the potential basically you get this + + + align:start position:0% +the potential basically you get this +formula one half and X dot squared plus + + align:start position:0% +formula one half and X dot squared plus + + + align:start position:0% +formula one half and X dot squared plus +one-half KX squared for last time we + + align:start position:0% +one-half KX squared for last time we + + + align:start position:0% +one-half KX squared for last time we +have solved this equation of motion + + align:start position:0% +have solved this equation of motion + + + align:start position:0% +have solved this equation of motion +right so that the solution we got is X + + align:start position:0% +right so that the solution we got is X + + + align:start position:0% +right so that the solution we got is X +equal to a cosine Omega 0 T plus Phi + + align:start position:0% +equal to a cosine Omega 0 T plus Phi + + + align:start position:0% +equal to a cosine Omega 0 T plus Phi +while Omega zero is equal to square root + + align:start position:0% +while Omega zero is equal to square root + + + align:start position:0% +while Omega zero is equal to square root +of K over m therefore we can actually + + align:start position:0% +of K over m therefore we can actually + + + align:start position:0% +of K over m therefore we can actually +calculate what would be the total energy + + align:start position:0% +calculate what would be the total energy + + + align:start position:0% +calculate what would be the total energy +as a function of time right so if we + + align:start position:0% +as a function of time right so if we + + + align:start position:0% +as a function of time right so if we +calculate that you'll get e will be + + align:start position:0% +calculate that you'll get e will be + + + align:start position:0% +calculate that you'll get e will be +equal to n over 2 n is square Omega 0 + + align:start position:0% +equal to n over 2 n is square Omega 0 + + + align:start position:0% +equal to n over 2 n is square Omega 0 +square sine squared Omega 0 T plus Phi + + align:start position:0% +square sine squared Omega 0 T plus Phi + + + align:start position:0% +square sine squared Omega 0 T plus Phi +so this is actually the first time ok + + align:start position:0% +so this is actually the first time ok + + + align:start position:0% +so this is actually the first time ok +here plus 1 over 2k a squared cosine + + align:start position:0% +here plus 1 over 2k a squared cosine + + + align:start position:0% +here plus 1 over 2k a squared cosine +squared Omega 0 T plus Phi ok + + align:start position:0% +squared Omega 0 T plus Phi ok + + + align:start position:0% +squared Omega 0 T plus Phi ok +and we also know that this this turn + + align:start position:0% +and we also know that this this turn + + + align:start position:0% +and we also know that this this turn +this issue a coefficient here is just + + align:start position:0% +this issue a coefficient here is just + + + align:start position:0% +this issue a coefficient here is just +ka square right because Omega zero is + + align:start position:0% +ka square right because Omega zero is + + + align:start position:0% +ka square right because Omega zero is +actually equal to square root of K over + + align:start position:0% +actually equal to square root of K over + + + align:start position:0% +actually equal to square root of K over +m and if you replace this Omega 0 square + + align:start position:0% +m and if you replace this Omega 0 square + + + align:start position:0% +m and if you replace this Omega 0 square +by by ko and then you actually arrive K + + align:start position:0% +by by ko and then you actually arrive K + + + align:start position:0% +by by ko and then you actually arrive K +a square okay so that is actually very + + align:start position:0% +a square okay so that is actually very + + + align:start position:0% +a square okay so that is actually very +good so that means I can simplify the + + align:start position:0% +good so that means I can simplify the + + + align:start position:0% +good so that means I can simplify the +total energy and what we are going to + + align:start position:0% +total energy and what we are going to + + + align:start position:0% +total energy and what we are going to +get is 1 over 2 ka square I can take + + align:start position:0% +get is 1 over 2 ka square I can take + + + align:start position:0% +get is 1 over 2 ka square I can take +this factor out and that will give me + + align:start position:0% +this factor out and that will give me + + + align:start position:0% +this factor out and that will give me +inside this bracket I will get sine + + align:start position:0% +inside this bracket I will get sine + + + align:start position:0% +inside this bracket I will get sine +square Omega 0 T plus Phi plus cosine + + align:start position:0% +square Omega 0 T plus Phi plus cosine + + + align:start position:0% +square Omega 0 T plus Phi plus cosine +square Omega 0 T plus Phi and this is + + align:start position:0% +square Omega 0 T plus Phi and this is + + + align:start position:0% +square Omega 0 T plus Phi and this is +actually equal to 1 right just a + + align:start position:0% +actually equal to 1 right just a + + + align:start position:0% +actually equal to 1 right just a +reminder sine squared theta plus cosine + + align:start position:0% +reminder sine squared theta plus cosine + + + align:start position:0% +reminder sine squared theta plus cosine +square theta is always equal to 1 so + + align:start position:0% +square theta is always equal to 1 so + + + align:start position:0% +square theta is always equal to 1 so +that give me this result this is a 1 + + align:start position:0% +that give me this result this is a 1 + + + align:start position:0% +that give me this result this is a 1 +over 2k + + align:start position:0% +over 2k + + + align:start position:0% +over 2k +a square ok so that is actually the + + align:start position:0% +a square ok so that is actually the + + + align:start position:0% +a square ok so that is actually the +result what does that mean that means if + + align:start position:0% +result what does that mean that means if + + + align:start position:0% +result what does that mean that means if +I actually put this mass harder okay so + + align:start position:0% +I actually put this mass harder okay so + + + align:start position:0% +I actually put this mass harder okay so +that the initial de has larger amplitude + + align:start position:0% +that the initial de has larger amplitude + + + align:start position:0% +that the initial de has larger amplitude +then the total energy is actually + + align:start position:0% +then the total energy is actually + + + align:start position:0% +then the total energy is actually +proportional to amplitude squared okay + + align:start position:0% +proportional to amplitude squared okay + + + align:start position:0% +proportional to amplitude squared okay +so I am storing more and more energy if + + align:start position:0% +so I am storing more and more energy if + + + align:start position:0% +so I am storing more and more energy if +I increase the temperature increase the + + align:start position:0% +I increase the temperature increase the + + + align:start position:0% +I increase the temperature increase the +amplitude even more than I'm storing the + + align:start position:0% +amplitude even more than I'm storing the + + + align:start position:0% +amplitude even more than I'm storing the +energy in this system and it's + + align:start position:0% +energy in this system and it's + + + align:start position:0% +energy in this system and it's +proportional to a square and also if the + + align:start position:0% +proportional to a square and also if the + + + align:start position:0% +proportional to a square and also if the +spring constant is larger the same + + align:start position:0% +spring constant is larger the same + + + align:start position:0% +spring constant is larger the same +amplitude will give you more energy so + + align:start position:0% +amplitude will give you more energy so + + + align:start position:0% +amplitude will give you more energy so +that means you can store more energy if + + align:start position:0% +that means you can store more energy if + + + align:start position:0% +that means you can store more energy if +you have larger spring constant okay the + + align:start position:0% +you have larger spring constant okay the + + + align:start position:0% +you have larger spring constant okay the +most surprising thing is that actually + + align:start position:0% +most surprising thing is that actually + + + align:start position:0% +most surprising thing is that actually +this is actually a constant right what + + align:start position:0% +this is actually a constant right what + + + align:start position:0% +this is actually a constant right what +does that mean the total energy is + + align:start position:0% +does that mean the total energy is + + + align:start position:0% +does that mean the total energy is +actually not varying as a function of + + align:start position:0% +actually not varying as a function of + + + align:start position:0% +actually not varying as a function of +time you see so total energy is + + align:start position:0% +time you see so total energy is + + + align:start position:0% +time you see so total energy is +conserved + + align:start position:0% +conserved + + + align:start position:0% +conserved +okay so you can see from this slide the + + align:start position:0% +okay so you can see from this slide the + + + align:start position:0% +okay so you can see from this slide the +total energy is actually shown as the + + align:start position:0% +total energy is actually shown as the + + + align:start position:0% +total energy is actually shown as the +sum which is the green curve and the + + align:start position:0% +sum which is the green curve and the + + + align:start position:0% +sum which is the green curve and the +kinetic energy and potential energy are + + align:start position:0% +kinetic energy and potential energy are + + + align:start position:0% +kinetic energy and potential energy are +shown as red and blue curves you can see + + align:start position:0% +shown as red and blue curves you can see + + + align:start position:0% +shown as red and blue curves you can see +that they are energy the total energy is + + align:start position:0% +that they are energy the total energy is + + + align:start position:0% +that they are energy the total energy is +actually constant but this system is + + align:start position:0% +actually constant but this system is + + + align:start position:0% +actually constant but this system is +very diamonique oh you see so the energy + + align:start position:0% +very diamonique oh you see so the energy + + + align:start position:0% +very diamonique oh you see so the energy +is actually going back and forth between + + align:start position:0% +is actually going back and forth between + + + align:start position:0% +is actually going back and forth between +the spring and a mass okay in the form + + align:start position:0% +the spring and a mass okay in the form + + + align:start position:0% +the spring and a mass okay in the form +of kinetic energy and in the form of + + align:start position:0% +of kinetic energy and in the form of + + + align:start position:0% +of kinetic energy and in the form of +potential energy but they are doing this + + align:start position:0% +potential energy but they are doing this + + + align:start position:0% +potential energy but they are doing this +so well such that the sum is actually a + + align:start position:0% +so well such that the sum is actually a + + + align:start position:0% +so well such that the sum is actually a +constant so energy is conserved okay so + + align:start position:0% +constant so energy is conserved okay so + + + align:start position:0% +constant so energy is conserved okay so +that is actually pretty beautiful and + + align:start position:0% +that is actually pretty beautiful and + + + align:start position:0% +that is actually pretty beautiful and +and can be described by very well about + + align:start position:0% +and can be described by very well about + + + align:start position:0% +and can be described by very well about +this mathematics any questions from here + + align:start position:0% + + + + align:start position:0% + +okay so I would like to say simple + + align:start position:0% +okay so I would like to say simple + + + align:start position:0% +okay so I would like to say simple +harmonic motion actually what you are + + align:start position:0% +harmonic motion actually what you are + + + align:start position:0% +harmonic motion actually what you are +going to get is the energy is as you can + + align:start position:0% +going to get is the energy is as you can + + + align:start position:0% +going to get is the energy is as you can +serve and independent that time and + + align:start position:0% +serve and independent that time and + + + align:start position:0% +serve and independent that time and +later you will see an example with + + align:start position:0% +later you will see an example with + + + align:start position:0% +later you will see an example with +stamping and you will see that energy + + align:start position:0% +stamping and you will see that energy + + + align:start position:0% +stamping and you will see that energy +conservation is no longer the case + + align:start position:0% +conservation is no longer the case + + + align:start position:0% +conservation is no longer the case +okay so that's immediately jump to + + align:start position:0% +okay so that's immediately jump to + + + align:start position:0% +okay so that's immediately jump to +another example which is a should be + + align:start position:0% +another example which is a should be + + + align:start position:0% +another example which is a should be +involving simple harmonic motion so + + align:start position:0% +involving simple harmonic motion so + + + align:start position:0% +involving simple harmonic motion so +let's take this rod and a nail system as + + align:start position:0% +let's take this rod and a nail system as + + + align:start position:0% +let's take this rod and a nail system as +an example if I actually slightly move + + align:start position:0% +an example if I actually slightly move + + + align:start position:0% +an example if I actually slightly move +this rod and then I release that then it + + align:start position:0% +this rod and then I release that then it + + + align:start position:0% +this rod and then I release that then it +was actually us see a simple harmonic + + align:start position:0% +was actually us see a simple harmonic + + + align:start position:0% +was actually us see a simple harmonic +motion okay also consistent so that's + + align:start position:0% +motion okay also consistent so that's + + + align:start position:0% +motion okay also consistent so that's +actually do the calculation as another + + align:start position:0% +actually do the calculation as another + + + align:start position:0% +actually do the calculation as another +example so this is actually my system I + + align:start position:0% +example so this is actually my system I + + + align:start position:0% +example so this is actually my system I +have this rod okay now I assume that + + align:start position:0% +have this rod okay now I assume that + + + align:start position:0% +have this rod okay now I assume that +that the mass is uniformly distributed + + align:start position:0% +that the mass is uniformly distributed + + + align:start position:0% +that the mass is uniformly distributed +and this rod and the snail down the war + + align:start position:0% +and this rod and the snail down the war + + + align:start position:0% +and this rod and the snail down the war +okay and the length of this rod is that + + align:start position:0% +okay and the length of this rod is that + + + align:start position:0% +okay and the length of this rod is that +you the L so that means the center of + + align:start position:0% +you the L so that means the center of + + + align:start position:0% +you the L so that means the center of +mass is actually at L over 2 with + + align:start position:0% +mass is actually at L over 2 with + + + align:start position:0% +mass is actually at L over 2 with +respect to the nail okay + + align:start position:0% +respect to the nail okay + + + align:start position:0% +respect to the nail okay +and also this whole system is set up and + + align:start position:0% +and also this whole system is set up and + + + align:start position:0% +and also this whole system is set up and +on earth right therefore there will be + + align:start position:0% +on earth right therefore there will be + + + align:start position:0% +on earth right therefore there will be +gravitational force pointing downward + + align:start position:0% +gravitational force pointing downward + + + align:start position:0% +gravitational force pointing downward +okay so that means you have rotational + + align:start position:0% +okay so that means you have rotational + + + align:start position:0% +okay so that means you have rotational +force FG pointing downward okay so this + + align:start position:0% +force FG pointing downward okay so this + + + align:start position:0% +force FG pointing downward okay so this +is actually the system which I would + + align:start position:0% +is actually the system which I would + + + align:start position:0% +is actually the system which I would +like to understand and that just a + + align:start position:0% +like to understand and that just a + + + align:start position:0% +like to understand and that just a +reminder what that we're going to do + + align:start position:0% +reminder what that we're going to do + + + align:start position:0% +reminder what that we're going to do +afterwards in order to turn the whole + + align:start position:0% +afterwards in order to turn the whole + + + align:start position:0% +afterwards in order to turn the whole +system into a language we will now + + align:start position:0% +system into a language we will now + + + align:start position:0% +system into a language we will now +describe the nature what is going to why + + align:start position:0% +describe the nature what is going to why + + + align:start position:0% +describe the nature what is going to why +we're going to do anybody we are going + + align:start position:0% +we're going to do anybody we are going + + + align:start position:0% +we're going to do anybody we are going +to define the coordinate system right so + + align:start position:0% +to define the coordinate system right so + + + align:start position:0% +to define the coordinate system right so +that I can translate everything into + + align:start position:0% +that I can translate everything into + + + align:start position:0% +that I can translate everything into +mathematics right so that's actually + + align:start position:0% +mathematics right so that's actually + + + align:start position:0% +mathematics right so that's actually +what we are always doing and you will + + align:start position:0% +what we are always doing and you will + + + align:start position:0% +what we are always doing and you will +see that we are always doing this in + + align:start position:0% +see that we are always doing this in + + + align:start position:0% +see that we are always doing this in +this class okay so how what is actually + + align:start position:0% +this class okay so how what is actually + + + align:start position:0% +this class okay so how what is actually +the coordinate system which I would like + + align:start position:0% +the coordinate system which I would like + + + align:start position:0% +the coordinate system which I would like +to use since this system is going to be + + align:start position:0% +to use since this system is going to be + + + align:start position:0% +to use since this system is going to be +rotating back and forth okay therefore I + + align:start position:0% +rotating back and forth okay therefore I + + + align:start position:0% +rotating back and forth okay therefore I +would like to define theta to be the + + align:start position:0% +would like to define theta to be the + + + align:start position:0% +would like to define theta to be the +angle with respect to axis which is + + align:start position:0% +angle with respect to axis which is + + + align:start position:0% +angle with respect to axis which is +actually pointing downward okay so the + + align:start position:0% +actually pointing downward okay so the + + + align:start position:0% +actually pointing downward okay so the +origin of this coordinate system is + + align:start position:0% +origin of this coordinate system is + + + align:start position:0% +origin of this coordinate system is +theta equal to zero this means that I'm + + align:start position:0% +theta equal to zero this means that I'm + + + align:start position:0% +theta equal to zero this means that I'm +pointing that okay that's rad is a ship + + align:start position:0% +pointing that okay that's rad is a ship + + + align:start position:0% +pointing that okay that's rad is a ship +pointing tango okay and also I need to + + align:start position:0% +pointing tango okay and also I need to + + + align:start position:0% +pointing tango okay and also I need to +define what is actually the positive + + align:start position:0% +define what is actually the positive + + + align:start position:0% +define what is actually the positive +what is actually the positive value of + + align:start position:0% +what is actually the positive value of + + + align:start position:0% +what is actually the positive value of +the theta right + + align:start position:0% +the theta right + + + align:start position:0% +the theta right +so I define anti-clockwise direction + + align:start position:0% +so I define anti-clockwise direction + + + align:start position:0% +so I define anti-clockwise direction +to be positive okay so it is actually + + align:start position:0% +to be positive okay so it is actually + + + align:start position:0% +to be positive okay so it is actually +important to say to h we first defined + + align:start position:0% +important to say to h we first defined + + + align:start position:0% +important to say to h we first defined +that then actually then actually to + + align:start position:0% +that then actually then actually to + + + align:start position:0% +that then actually then actually to +translate everything into mathematics + + align:start position:0% +translate everything into mathematics + + + align:start position:0% +translate everything into mathematics +okay so the initial condition is the + + align:start position:0% +okay so the initial condition is the + + + align:start position:0% +okay so the initial condition is the +following so I actually move this thing + + align:start position:0% +following so I actually move this thing + + + align:start position:0% +following so I actually move this thing +rotate this inside D then I actually + + align:start position:0% +rotate this inside D then I actually + + + align:start position:0% +rotate this inside D then I actually +reduce that really carefully without + + align:start position:0% +reduce that really carefully without + + + align:start position:0% +reduce that really carefully without +introducing any initial velocity okay + + align:start position:0% +introducing any initial velocity okay + + + align:start position:0% +introducing any initial velocity okay +therefore I have two initial conditions + + align:start position:0% + + + + align:start position:0% + +okay at T equal to zero there are two + + align:start position:0% +okay at T equal to zero there are two + + + align:start position:0% +okay at T equal to zero there are two +initial conditions + + align:start position:0% +initial conditions + + + align:start position:0% +initial conditions +the first one is theta equal to theta 0 + + align:start position:0% +the first one is theta equal to theta 0 + + + align:start position:0% +the first one is theta equal to theta 0 +this equal to theta initial the second + + align:start position:0% +this equal to theta initial the second + + + align:start position:0% +this equal to theta initial the second +condition is the same as what we have + + align:start position:0% +condition is the same as what we have + + + align:start position:0% +condition is the same as what we have +been doing last time the initial + + align:start position:0% +been doing last time the initial + + + align:start position:0% +been doing last time the initial +velocity or angular velocity is actually + + align:start position:0% +velocity or angular velocity is actually + + + align:start position:0% +velocity or angular velocity is actually +equal to 0 so that gives you theta dot + + align:start position:0% +equal to 0 so that gives you theta dot + + + align:start position:0% +equal to 0 so that gives you theta dot +equal to 0 okay now we have actually + + align:start position:0% +equal to 0 okay now we have actually + + + align:start position:0% +equal to 0 okay now we have actually +define the coordinate system then now we + + align:start position:0% +define the coordinate system then now we + + + align:start position:0% +define the coordinate system then now we +can issue the draw a force diagram right + + align:start position:0% +can issue the draw a force diagram right + + + align:start position:0% +can issue the draw a force diagram right +so that we can actually use the null our + + align:start position:0% +so that we can actually use the null our + + + align:start position:0% +so that we can actually use the null our +knowledge about the physics and to + + align:start position:0% +knowledge about the physics and to + + + align:start position:0% +knowledge about the physics and to +obtain the equation of motion right so + + align:start position:0% +obtain the equation of motion right so + + + align:start position:0% +obtain the equation of motion right so +now the force diagram looks like this so + + align:start position:0% +now the force diagram looks like this so + + + align:start position:0% +now the force diagram looks like this so +this is actually the center of mass of + + align:start position:0% +this is actually the center of mass of + + + align:start position:0% +this is actually the center of mass of +this rod and you have a force pointing + + align:start position:0% +this rod and you have a force pointing + + + align:start position:0% +this rod and you have a force pointing +downward which is due to the + + align:start position:0% +downward which is due to the + + + align:start position:0% +downward which is due to the +gravitational force FG is equal to mg + + align:start position:0% +gravitational force FG is equal to mg + + + align:start position:0% +gravitational force FG is equal to mg +okay is pointing downward okay the + + align:start position:0% +okay is pointing downward okay the + + + align:start position:0% +okay is pointing downward okay the +magnitude is actually equal to mg and + + align:start position:0% + + + + align:start position:0% + +and also we know the R vector this + + align:start position:0% +and also we know the R vector this + + + align:start position:0% +and also we know the R vector this +vector have a length of L over 2 + + align:start position:0% +vector have a length of L over 2 + + + align:start position:0% +vector have a length of L over 2 +pointing from the center of mass of this + + align:start position:0% +pointing from the center of mass of this + + + align:start position:0% +pointing from the center of mass of this +rod to the tuna net okay and also we + + align:start position:0% +rod to the tuna net okay and also we + + + align:start position:0% +rod to the tuna net okay and also we +know the angle between this vector + + align:start position:0% +know the angle between this vector + + + align:start position:0% +know the angle between this vector +pointing from the center of mass to the + + align:start position:0% +pointing from the center of mass to the + + + align:start position:0% +pointing from the center of mass to the +nail and the vertical direction which we + + align:start position:0% +nail and the vertical direction which we + + + align:start position:0% +nail and the vertical direction which we +have already defined which is actually + + align:start position:0% +have already defined which is actually + + + align:start position:0% +have already defined which is actually +called Sita therefore now we can + + align:start position:0% +called Sita therefore now we can + + + align:start position:0% +called Sita therefore now we can +actually calculate wobbler the torque + + align:start position:0% +actually calculate wobbler the torque + + + align:start position:0% +actually calculate wobbler the torque +tau will be equal to this R vector plus + + align:start position:0% +tau will be equal to this R vector plus + + + align:start position:0% +tau will be equal to this R vector plus +the force the total force acting on the + + align:start position:0% +the force the total force acting on the + + + align:start position:0% +the force the total force acting on the +the center of mass in this case is just + + align:start position:0% +the center of mass in this case is just + + + align:start position:0% +the center of mass in this case is just +F G okay so now we can actually write + + align:start position:0% +F G okay so now we can actually write + + + align:start position:0% +F G okay so now we can actually write +this explicitly since the whole system + + align:start position:0% +this explicitly since the whole system + + + align:start position:0% +this explicitly since the whole system +is actually rotating on a single plane + + align:start position:0% +is actually rotating on a single plane + + + align:start position:0% +is actually rotating on a single plane +right so there's only one plan this rod + + align:start position:0% +right so there's only one plan this rod + + + align:start position:0% +right so there's only one plan this rod +is sitting up and it's actually going + + align:start position:0% +is sitting up and it's actually going + + + align:start position:0% +is sitting up and it's actually going +back and forth only on this prep okay + + align:start position:0% +back and forth only on this prep okay + + + align:start position:0% +back and forth only on this prep okay +therefore actually I can drop all the + + align:start position:0% +therefore actually I can drop all the + + + align:start position:0% +therefore actually I can drop all the +arrows and write it down the magnitude + + align:start position:0% +arrows and write it down the magnitude + + + align:start position:0% +arrows and write it down the magnitude +of the Tau directly and this will be + + align:start position:0% +of the Tau directly and this will be + + + align:start position:0% +of the Tau directly and this will be +equal to minus and G L over 2 sine theta + + align:start position:0% + + + + align:start position:0% + +okay any questions so far + + align:start position:0% + + + + align:start position:0% + +okay so now we have the talk and the + + align:start position:0% +okay so now we have the talk and the + + + align:start position:0% +okay so now we have the talk and the +weekend you make use the rotational + + align:start position:0% +weekend you make use the rotational + + + align:start position:0% +weekend you make use the rotational +version of Newton's law to obtain the + + align:start position:0% +version of Newton's law to obtain the + + + align:start position:0% +version of Newton's law to obtain the +equation of motion right so that should + + align:start position:0% +equation of motion right so that should + + + align:start position:0% +equation of motion right so that should +be pretty straightforward tau will be + + align:start position:0% +be pretty straightforward tau will be + + + align:start position:0% +be pretty straightforward tau will be +equal to I which is smooth the moment of + + align:start position:0% +equal to I which is smooth the moment of + + + align:start position:0% +equal to I which is smooth the moment of +inertia of the system and times alpha + + align:start position:0% +inertia of the system and times alpha + + + align:start position:0% +inertia of the system and times alpha +okay and there's just for your + + align:start position:0% +okay and there's just for your + + + align:start position:0% +okay and there's just for your +information I already calculated the AI + + align:start position:0% +information I already calculated the AI + + + align:start position:0% +information I already calculated the AI +for you I is equal to 1/3 and l squared + + align:start position:0% +for you I is equal to 1/3 and l squared + + + align:start position:0% +for you I is equal to 1/3 and l squared +okay so you can actually go back home + + align:start position:0% +okay so you can actually go back home + + + align:start position:0% +okay so you can actually go back home +and that actually to a check to see if I + + align:start position:0% +and that actually to a check to see if I + + + align:start position:0% +and that actually to a check to see if I +entered in the tools and if you trust me + + align:start position:0% +entered in the tools and if you trust me + + + align:start position:0% +entered in the tools and if you trust me +and that's and the answer which is + + align:start position:0% +and that's and the answer which is + + + align:start position:0% +and that's and the answer which is +actually 1 over 3 and L square if the + + align:start position:0% +actually 1 over 3 and L square if the + + + align:start position:0% +actually 1 over 3 and L square if the +mass is uniformly distributed on this + + align:start position:0% +mass is uniformly distributed on this + + + align:start position:0% +mass is uniformly distributed on this +rod okay so that will give me minus n 2 + + align:start position:0% +rod okay so that will give me minus n 2 + + + align:start position:0% +rod okay so that will give me minus n 2 +L divided by 2 sine theta ok so that is + + align:start position:0% +L divided by 2 sine theta ok so that is + + + align:start position:0% +L divided by 2 sine theta ok so that is +actually coming from from this side okay + + align:start position:0% +actually coming from from this side okay + + + align:start position:0% +actually coming from from this side okay +so now I can actually simplify this + + align:start position:0% +so now I can actually simplify this + + + align:start position:0% +so now I can actually simplify this +expression I can now practice the I + + align:start position:0% +expression I can now practice the I + + + align:start position:0% +expression I can now practice the I +value into this equation and I will get + + align:start position:0% + + + + align:start position:0% + +1 over 3 and L square theta double dot P + + align:start position:0% +1 over 3 and L square theta double dot P + + + align:start position:0% +1 over 3 and L square theta double dot P +which is actually alpha okay I now + + align:start position:0% +which is actually alpha okay I now + + + align:start position:0% +which is actually alpha okay I now +dreaded as a seat at about dot and that + + align:start position:0% +dreaded as a seat at about dot and that + + + align:start position:0% +dreaded as a seat at about dot and that +will be equal to minus and G L over 2 + + align:start position:0% +will be equal to minus and G L over 2 + + + align:start position:0% +will be equal to minus and G L over 2 +sine theta okay I can move all the + + align:start position:0% +sine theta okay I can move all the + + + align:start position:0% +sine theta okay I can move all the +constant to the right hand side + + align:start position:0% +constant to the right hand side + + + align:start position:0% +constant to the right hand side +therefore I get theta double dot T this + + align:start position:0% +therefore I get theta double dot T this + + + align:start position:0% +therefore I get theta double dot T this +is equal to minus and gee L okay + + align:start position:0% +is equal to minus and gee L okay + + + align:start position:0% +is equal to minus and gee L okay +actually I can - you already simplify + + align:start position:0% +actually I can - you already simplify + + + align:start position:0% +actually I can - you already simplify +this right + + align:start position:0% +this right + + + align:start position:0% +this right +this says you cancel and why one of the + + align:start position:0% +this says you cancel and why one of the + + + align:start position:0% +this says you cancel and why one of the +L as you can so so therefore I get - 3G + + align:start position:0% +L as you can so so therefore I get - 3G + + + align:start position:0% +L as you can so so therefore I get - 3G +over 2 sine theta ok as judo we actually + + align:start position:0% +over 2 sine theta ok as judo we actually + + + align:start position:0% +over 2 sine theta ok as judo we actually +define a Omega to repress this kind of + + align:start position:0% +define a Omega to repress this kind of + + + align:start position:0% +define a Omega to repress this kind of +this constant to make our life easier + + align:start position:0% +this constant to make our life easier + + + align:start position:0% +this constant to make our life easier +so I can now define Omega 0 equal to + + align:start position:0% +so I can now define Omega 0 equal to + + + align:start position:0% +so I can now define Omega 0 equal to +square root of 3G over 2l okay and that + + align:start position:0% +square root of 3G over 2l okay and that + + + align:start position:0% +square root of 3G over 2l okay and that +will give you CPAP double dot e equal to + + align:start position:0% +will give you CPAP double dot e equal to + + + align:start position:0% +will give you CPAP double dot e equal to +minus Omega 0 square sine theta any + + align:start position:0% +minus Omega 0 square sine theta any + + + align:start position:0% +minus Omega 0 square sine theta any +questions so far a lot of calculation + + align:start position:0% +questions so far a lot of calculation + + + align:start position:0% +questions so far a lot of calculation +but I should be all pretty + + align:start position:0% +but I should be all pretty + + + align:start position:0% +but I should be all pretty +straightforward and HD we are done no we + + align:start position:0% +straightforward and HD we are done no we + + + align:start position:0% +straightforward and HD we are done no we +are done because we have the equation of + + align:start position:0% +are done because we have the equation of + + + align:start position:0% +are done because we have the equation of +motion and the rest of the job is to + + align:start position:0% +motion and the rest of the job is to + + + align:start position:0% +motion and the rest of the job is to +just solve it so this is actually now + + align:start position:0% +just solve it so this is actually now + + + align:start position:0% +just solve it so this is actually now +the the problem of the maths Department + + align:start position:0% +the the problem of the maths Department + + + align:start position:0% +the the problem of the maths Department +so can anybody as you tell me the + + align:start position:0% +so can anybody as you tell me the + + + align:start position:0% +so can anybody as you tell me the +solution of the seat of t anybody so + + align:start position:0% +solution of the seat of t anybody so + + + align:start position:0% +solution of the seat of t anybody so +that now we are facing a very difficult + + align:start position:0% +that now we are facing a very difficult + + + align:start position:0% +that now we are facing a very difficult +situation we don't know how to solve + + align:start position:0% +situation we don't know how to solve + + + align:start position:0% +situation we don't know how to solve +this equation in front of you I I don't + + align:start position:0% +this equation in front of you I I don't + + + align:start position:0% +this equation in front of you I I don't +know okay of course you can easily solve + + align:start position:0% +know okay of course you can easily solve + + + align:start position:0% +know okay of course you can easily solve +it with a computer ok or you want to go + + align:start position:0% +it with a computer ok or you want to go + + + align:start position:0% +it with a computer ok or you want to go +fancy solve it with your cellphone + + align:start position:0% +fancy solve it with your cellphone + + + align:start position:0% +fancy solve it with your cellphone +if we turn X Pro but it's not very nice + + align:start position:0% +if we turn X Pro but it's not very nice + + + align:start position:0% +if we turn X Pro but it's not very nice +to do this in front of you yeah we don't + + align:start position:0% +to do this in front of you yeah we don't + + + align:start position:0% +to do this in front of you yeah we don't +learn too much ok so what are we going + + align:start position:0% +learn too much ok so what are we going + + + align:start position:0% +learn too much ok so what are we going +to do so what we can do is actually to + + align:start position:0% +to do so what we can do is actually to + + + align:start position:0% +to do so what we can do is actually to +consider a special case + + align:start position:0% +consider a special case + + + align:start position:0% +consider a special case +so we know that this equation of motion + + align:start position:0% +so we know that this equation of motion + + + align:start position:0% +so we know that this equation of motion +is exact okay so if you solve it it + + align:start position:0% +is exact okay so if you solve it it + + + align:start position:0% +is exact okay so if you solve it it +would describe the motion of this this + + align:start position:0% +would describe the motion of this this + + + align:start position:0% +would describe the motion of this this +rod the motion of this the same even + + align:start position:0% +rod the motion of this the same even + + + align:start position:0% +rod the motion of this the same even +with slash angle it works okay and now + + align:start position:0% +with slash angle it works okay and now + + + align:start position:0% +with slash angle it works okay and now +in order to actually to show you the + + align:start position:0% +in order to actually to show you the + + + align:start position:0% +in order to actually to show you the +mass if in the class therefore actually + + align:start position:0% +mass if in the class therefore actually + + + align:start position:0% +mass if in the class therefore actually +I were to a small approximation so I + + align:start position:0% +I were to a small approximation so I + + + align:start position:0% +I were to a small approximation so I +should I would only work on the case + + align:start position:0% +should I would only work on the case + + + align:start position:0% +should I would only work on the case +that when the amplitude is very small + + align:start position:0% +that when the amplitude is very small + + + align:start position:0% +that when the amplitude is very small +and see what is going to happen so now + + align:start position:0% +and see what is going to happen so now + + + align:start position:0% +and see what is going to happen so now +I'm considered in a special case up to + + align:start position:0% +I'm considered in a special case up to + + + align:start position:0% +I'm considered in a special case up to +now everything is exact and now I'm now + + align:start position:0% +now everything is exact and now I'm now + + + align:start position:0% +now everything is exact and now I'm now +going to a special case see top T goes + + align:start position:0% +going to a special case see top T goes + + + align:start position:0% +going to a special case see top T goes +to 0 okay then we can actually get this + + align:start position:0% +to 0 okay then we can actually get this + + + align:start position:0% +to 0 okay then we can actually get this +sine theta P is roughly C Turkey okay + + align:start position:0% +sine theta P is roughly C Turkey okay + + + align:start position:0% +sine theta P is roughly C Turkey okay +based on the Tyler expansion you can + + align:start position:0% +based on the Tyler expansion you can + + + align:start position:0% +based on the Tyler expansion you can +actually verify this okay so in this + + align:start position:0% +actually verify this okay so in this + + + align:start position:0% +actually verify this okay so in this +case if we take Sita equal to one degree + + align:start position:0% +case if we take Sita equal to one degree + + + align:start position:0% +case if we take Sita equal to one degree +okay then the ratio of the sine theta + + align:start position:0% +okay then the ratio of the sine theta + + + align:start position:0% +okay then the ratio of the sine theta +and the Sita is actually equal to 99.99% + + align:start position:0% +and the Sita is actually equal to 99.99% + + + align:start position:0% +and the Sita is actually equal to 99.99% +which is very good if I take it as like + + align:start position:0% +which is very good if I take it as like + + + align:start position:0% +which is very good if I take it as like +five percent then I get ninety nine so + + align:start position:0% +five percent then I get ninety nine so + + + align:start position:0% +five percent then I get ninety nine so +at five degree okay and this issue in + + align:start position:0% +at five degree okay and this issue in + + + align:start position:0% +at five degree okay and this issue in +nineteen ninety nine percent even a tank + + align:start position:0% +nineteen ninety nine percent even a tank + + + align:start position:0% +nineteen ninety nine percent even a tank +degree okay it says should be 99.5 + + align:start position:0% +degree okay it says should be 99.5 + + + align:start position:0% +degree okay it says should be 99.5 +percent that shows you that science it + + align:start position:0% +percent that shows you that science it + + + align:start position:0% +percent that shows you that science it +has so close to Sita okay we are pretty + + align:start position:0% +has so close to Sita okay we are pretty + + + align:start position:0% +has so close to Sita okay we are pretty +safe because the difference is smaller + + align:start position:0% +safe because the difference is smaller + + + align:start position:0% +safe because the difference is smaller +than one percent okay so that's really + + align:start position:0% +than one percent okay so that's really + + + align:start position:0% +than one percent okay so that's really +nice after this approximation okay I get + + align:start position:0% +nice after this approximation okay I get + + + align:start position:0% +nice after this approximation okay I get +my final equation of motion Sita double + + align:start position:0% +my final equation of motion Sita double + + + align:start position:0% +my final equation of motion Sita double +dot T equal to minus Omega 0 square + + align:start position:0% +dot T equal to minus Omega 0 square + + + align:start position:0% +dot T equal to minus Omega 0 square +Sita just a reminder Omega zero is equal + + align:start position:0% +Sita just a reminder Omega zero is equal + + + align:start position:0% +Sita just a reminder Omega zero is equal +to square root of 3G over 2l okay we + + align:start position:0% +to square root of 3G over 2l okay we + + + align:start position:0% +to square root of 3G over 2l okay we +have solved this equation last time last + + align:start position:0% +have solved this equation last time last + + + align:start position:0% +have solved this equation last time last +lecture right it's exactly the same + + align:start position:0% +lecture right it's exactly the same + + + align:start position:0% +lecture right it's exactly the same +okay happen to be exactly the same + + align:start position:0% +okay happen to be exactly the same + + + align:start position:0% +okay happen to be exactly the same +therefore I know the solution will be + + align:start position:0% +therefore I know the solution will be + + + align:start position:0% +therefore I know the solution will be +Sita with T equal to a cosine Omega 0 T + + align:start position:0% +Sita with T equal to a cosine Omega 0 T + + + align:start position:0% +Sita with T equal to a cosine Omega 0 T +transfer from the initial conditions + + align:start position:0% +transfer from the initial conditions + + + align:start position:0% +transfer from the initial conditions +which I have one and the two okay I'm + + align:start position:0% +which I have one and the two okay I'm + + + align:start position:0% +which I have one and the two okay I'm +not going to go over this calculation + + align:start position:0% +not going to go over this calculation + + + align:start position:0% +not going to go over this calculation +again but again we can actually plug in + + align:start position:0% +again but again we can actually plug in + + + align:start position:0% +again but again we can actually plug in +1 and 2 to solve the unknown a and Phi + + align:start position:0% +1 and 2 to solve the unknown a and Phi + + + align:start position:0% +1 and 2 to solve the unknown a and Phi +if you do this exercise you will + + align:start position:0% +if you do this exercise you will + + + align:start position:0% +if you do this exercise you will +conclude that a is equal to theta + + align:start position:0% +conclude that a is equal to theta + + + align:start position:0% +conclude that a is equal to theta +initial and Phi is equal to zero okay so + + align:start position:0% +initial and Phi is equal to zero okay so + + + align:start position:0% +initial and Phi is equal to zero okay so +what the solution will be seated with T + + align:start position:0% +what the solution will be seated with T + + + align:start position:0% +what the solution will be seated with T +equal to a ok so n is now replaced by + + align:start position:0% +equal to a ok so n is now replaced by + + + align:start position:0% +equal to a ok so n is now replaced by +theta initial cosine Omega 0 you can see + + align:start position:0% +theta initial cosine Omega 0 you can see + + + align:start position:0% +theta initial cosine Omega 0 you can see +that this actually works for this system + + align:start position:0% +that this actually works for this system + + + align:start position:0% +that this actually works for this system +simple harmonic oscillation actually + + align:start position:0% +simple harmonic oscillation actually + + + align:start position:0% +simple harmonic oscillation actually +described this the motion of this system + + align:start position:0% +described this the motion of this system + + + align:start position:0% +described this the motion of this system +as a function of time you can also see a + + align:start position:0% +as a function of time you can also see a + + + align:start position:0% +as a function of time you can also see a +few more example showing here to obtain + + align:start position:0% +few more example showing here to obtain + + + align:start position:0% +few more example showing here to obtain +you are going to actually work on in + + align:start position:0% +you are going to actually work on in + + + align:start position:0% +you are going to actually work on in +your pset and also another one involving + + align:start position:0% +your pset and also another one involving + + + align:start position:0% +your pset and also another one involving +circuit if you have a capacitor and you + + align:start position:0% +circuit if you have a capacitor and you + + + align:start position:0% +circuit if you have a capacitor and you +have a daughter actually the the current + + align:start position:0% +have a daughter actually the the current + + + align:start position:0% +have a daughter actually the the current +the size of the current is also doing a + + align:start position:0% +the size of the current is also doing a + + + align:start position:0% +the size of the current is also doing a +simple harmonic motion okay and as we + + align:start position:0% +simple harmonic motion okay and as we + + + align:start position:0% +simple harmonic motion okay and as we +actually discussed before the energy is + + align:start position:0% +actually discussed before the energy is + + + align:start position:0% +actually discussed before the energy is +always conserved + + align:start position:0% +always conserved + + + align:start position:0% +always conserved +and it's actually stored in different + + align:start position:0% +and it's actually stored in different + + + align:start position:0% +and it's actually stored in different +components of the systems okay so we + + align:start position:0% +components of the systems okay so we + + + align:start position:0% +components of the systems okay so we +have done this what is actually new + + align:start position:0% +have done this what is actually new + + + align:start position:0% +have done this what is actually new +today what we are going to do today is + + align:start position:0% +today what we are going to do today is + + + align:start position:0% +today what we are going to do today is +that's actually observe this phenomena + + align:start position:0% +that's actually observe this phenomena + + + align:start position:0% +that's actually observe this phenomena +here so this thing is actually going to + + align:start position:0% +here so this thing is actually going to + + + align:start position:0% +here so this thing is actually going to +go back and forth but it's actually not + + align:start position:0% +go back and forth but it's actually not + + + align:start position:0% +go back and forth but it's actually not +going to do that forever right + + align:start position:0% +going to do that forever right + + + align:start position:0% +going to do that forever right +something is happening which I should + + align:start position:0% +something is happening which I should + + + align:start position:0% +something is happening which I should +slow the motion damn I can also you make + + align:start position:0% +slow the motion damn I can also you make + + + align:start position:0% +slow the motion damn I can also you make +use of this system okay I start from + + align:start position:0% +use of this system okay I start from + + + align:start position:0% +use of this system okay I start from +from here and I not worried that this + + align:start position:0% +from here and I not worried that this + + + align:start position:0% +from here and I not worried that this +issue goes out of the of this track + + align:start position:0% +issue goes out of the of this track + + + align:start position:0% +issue goes out of the of this track +because I know for sure you will stop + + align:start position:0% +because I know for sure you will stop + + + align:start position:0% +because I know for sure you will stop +there why because the initial amplitude + + align:start position:0% +there why because the initial amplitude + + + align:start position:0% +there why because the initial amplitude +okay it's not going to okay so the mp2 + + align:start position:0% +okay it's not going to okay so the mp2 + + + align:start position:0% +okay it's not going to okay so the mp2 +is not going to be larger than the + + align:start position:0% +is not going to be larger than the + + + align:start position:0% +is not going to be larger than the +initial amplitude right so I'm now + + align:start position:0% +initial amplitude right so I'm now + + + align:start position:0% +initial amplitude right so I'm now +worried at all okay but you can see that + + align:start position:0% +worried at all okay but you can see that + + + align:start position:0% +worried at all okay but you can see that +the amplitude is changing as a function + + align:start position:0% +the amplitude is changing as a function + + + align:start position:0% +the amplitude is changing as a function +of time apparently something is missing + + align:start position:0% +of time apparently something is missing + + + align:start position:0% +of time apparently something is missing +and that is actually a drag force work + + align:start position:0% +and that is actually a drag force work + + + align:start position:0% +and that is actually a drag force work +or friction which is actually not + + align:start position:0% +or friction which is actually not + + + align:start position:0% +or friction which is actually not +including in included in our calculation + + align:start position:0% +including in included in our calculation + + + align:start position:0% +including in included in our calculation +so that actually try to make the + + align:start position:0% +so that actually try to make the + + + align:start position:0% +so that actually try to make the +calculation more realistic and see what + + align:start position:0% +calculation more realistic and see what + + + align:start position:0% +calculation more realistic and see what +is going to happen so now I will + + align:start position:0% +is going to happen so now I will + + + align:start position:0% +is going to happen so now I will +introduce a drag force okay which I + + align:start position:0% +introduce a drag force okay which I + + + align:start position:0% +introduce a drag force okay which I +should introduce a torque tau drag T + + align:start position:0% +should introduce a torque tau drag T + + + align:start position:0% +should introduce a torque tau drag T +which is equal to minus P P is a some + + align:start position:0% +which is equal to minus P P is a some + + + align:start position:0% +which is equal to minus P P is a some +kind of constant which is given to you + + align:start position:0% +kind of constant which is given to you + + + align:start position:0% +kind of constant which is given to you +Seeta thought he which is actually + + align:start position:0% +Seeta thought he which is actually + + + align:start position:0% +Seeta thought he which is actually +proportional to the angular velocity of + + align:start position:0% +proportional to the angular velocity of + + + align:start position:0% +proportional to the angular velocity of +that rod okay and also of course I keep + + align:start position:0% +that rod okay and also of course I keep + + + align:start position:0% +that rod okay and also of course I keep +the original approximation the CETA is + + align:start position:0% +the original approximation the CETA is + + + align:start position:0% +the original approximation the CETA is +very small such that I don't have to + + align:start position:0% +very small such that I don't have to + + + align:start position:0% +very small such that I don't have to +tell with the integration of science + + align:start position:0% +tell with the integration of science + + + align:start position:0% +tell with the integration of science +system okay so being this out about + + align:start position:0% +system okay so being this out about + + + align:start position:0% +system okay so being this out about +dot equal to minus Omega 0 square sine + + align:start position:0% +dot equal to minus Omega 0 square sine + + + align:start position:0% +dot equal to minus Omega 0 square sine +theta this complicated function okay you + + align:start position:0% +theta this complicated function okay you + + + align:start position:0% +theta this complicated function okay you +may ask why do I actually introduce a + + align:start position:0% +may ask why do I actually introduce a + + + align:start position:0% +may ask why do I actually introduce a +drag force proportional to the velocity + + align:start position:0% +drag force proportional to the velocity + + + align:start position:0% +drag force proportional to the velocity +okay and why do we put a minus sign + + align:start position:0% +okay and why do we put a minus sign + + + align:start position:0% +okay and why do we put a minus sign +there okay that is essentially because + + align:start position:0% +there okay that is essentially because + + + align:start position:0% +there okay that is essentially because +if you have a minus sign okay that means + + align:start position:0% +if you have a minus sign okay that means + + + align:start position:0% +if you have a minus sign okay that means +when this mass or that rod is actually + + align:start position:0% +when this mass or that rod is actually + + + align:start position:0% +when this mass or that rod is actually +for example it's actually going downward + + align:start position:0% +for example it's actually going downward + + + align:start position:0% +for example it's actually going downward +then the track force is really tracking + + align:start position:0% +then the track force is really tracking + + + align:start position:0% +then the track force is really tracking +it because it's actually in the opposite + + align:start position:0% +it because it's actually in the opposite + + + align:start position:0% +it because it's actually in the opposite +direction of the velocity of the mass or + + align:start position:0% +direction of the velocity of the mass or + + + align:start position:0% +direction of the velocity of the mass or +the angular velocity of the rod okay so + + align:start position:0% +the angular velocity of the rod okay so + + + align:start position:0% +the angular velocity of the rod okay so +I need a minus sign there okay otherwise + + align:start position:0% +I need a minus sign there okay otherwise + + + align:start position:0% +I need a minus sign there okay otherwise +sign it's not a track force anymore it's + + align:start position:0% +sign it's not a track force anymore it's + + + align:start position:0% +sign it's not a track force anymore it's +actually accelerating the whole thing + + align:start position:0% +actually accelerating the whole thing + + + align:start position:0% +actually accelerating the whole thing +okay + + align:start position:0% +okay + + + align:start position:0% +okay +secondly why is that why do I choose + + align:start position:0% +secondly why is that why do I choose + + + align:start position:0% +secondly why is that why do I choose +that to be proportional to sit a dot + + align:start position:0% +that to be proportional to sit a dot + + + align:start position:0% +that to be proportional to sit a dot +over velocity okay + + align:start position:0% +over velocity okay + + + align:start position:0% +over velocity okay +there's really no much deeper reason I + + align:start position:0% +there's really no much deeper reason I + + + align:start position:0% +there's really no much deeper reason I +choose this form because I can actually + + align:start position:0% +choose this form because I can actually + + + align:start position:0% +choose this form because I can actually +solve it in front of you + + align:start position:0% +solve it in front of you + + + align:start position:0% +solve it in front of you +okay the reality is actually between + + align:start position:0% +okay the reality is actually between + + + align:start position:0% +okay the reality is actually between +proportional to theta dot and theta dot + + align:start position:0% +proportional to theta dot and theta dot + + + align:start position:0% +proportional to theta dot and theta dot +square for example okay + + align:start position:0% +square for example okay + + + align:start position:0% +square for example okay +this is your model which I introduce + + align:start position:0% +this is your model which I introduce + + + align:start position:0% +this is your model which I introduce +here which I can actually solve it in + + align:start position:0% +here which I can actually solve it in + + + align:start position:0% +here which I can actually solve it in +front of you okay on the other hand you + + align:start position:0% +front of you okay on the other hand you + + + align:start position:0% +front of you okay on the other hand you +will see that it's actually not bad at + + align:start position:0% +will see that it's actually not bad at + + + align:start position:0% +will see that it's actually not bad at +all okay it actually works and the + + align:start position:0% +all okay it actually works and the + + + align:start position:0% +all okay it actually works and the +describe the system which we actually + + align:start position:0% +describe the system which we actually + + + align:start position:0% +describe the system which we actually +work perform the demo here okay and once + + align:start position:0% +work perform the demo here okay and once + + + align:start position:0% +work perform the demo here okay and once +we have introduced this okay the + + align:start position:0% +we have introduced this okay the + + + align:start position:0% +we have introduced this okay the +equation of motion will be modified okay + + align:start position:0% +equation of motion will be modified okay + + + align:start position:0% +equation of motion will be modified okay +so that's come back to the equation of + + align:start position:0% +so that's come back to the equation of + + + align:start position:0% +so that's come back to the equation of +motion so you have theta double dot he + + align:start position:0% +motion so you have theta double dot he + + + align:start position:0% +motion so you have theta double dot he +originally will be equal to tau Toto P + + align:start position:0% +originally will be equal to tau Toto P + + + align:start position:0% +originally will be equal to tau Toto P +/ I okay and now this will become tau t + + align:start position:0% +/ I okay and now this will become tau t + + + align:start position:0% +/ I okay and now this will become tau t +plus tau drag T / app there's additional + + align:start position:0% +plus tau drag T / app there's additional + + + align:start position:0% +plus tau drag T / app there's additional +time here okay if I simplify this whole + + align:start position:0% +time here okay if I simplify this whole + + + align:start position:0% +time here okay if I simplify this whole +equation then I get minus mg L / - okay + + align:start position:0% +equation then I get minus mg L / - okay + + + align:start position:0% +equation then I get minus mg L / - okay +signs theta and this is actually roughly + + align:start position:0% +signs theta and this is actually roughly + + + align:start position:0% +signs theta and this is actually roughly +Sita okay - P Sita dot divided by + + align:start position:0% +Sita okay - P Sita dot divided by + + + align:start position:0% +Sita okay - P Sita dot divided by +one-third of M L square okay so you can + + align:start position:0% +one-third of M L square okay so you can + + + align:start position:0% +one-third of M L square okay so you can +see that I still make this approximation + + align:start position:0% +see that I still make this approximation + + + align:start position:0% +see that I still make this approximation +sine theta roughly equal to Sita okay + + align:start position:0% +sine theta roughly equal to Sita okay + + + align:start position:0% +sine theta roughly equal to Sita okay +then I can actually write this equation + + align:start position:0% +then I can actually write this equation + + + align:start position:0% +then I can actually write this equation +in a small angle case okay I get minus + + align:start position:0% +in a small angle case okay I get minus + + + align:start position:0% +in a small angle case okay I get minus +3G over 2l Sita + + align:start position:0% +3G over 2l Sita + + + align:start position:0% +3G over 2l Sita +t minus 3b over and L square theta dot + + align:start position:0% + + + + align:start position:0% + +okay and now I as usual I define Omega 0 + + align:start position:0% +okay and now I as usual I define Omega 0 + + + align:start position:0% +okay and now I as usual I define Omega 0 +square equal to 3G over 2l and I can + + align:start position:0% +square equal to 3G over 2l and I can + + + align:start position:0% +square equal to 3G over 2l and I can +also define gamma is equal to CP / ml + + align:start position:0% +also define gamma is equal to CP / ml + + + align:start position:0% +also define gamma is equal to CP / ml +squared okay just to make my life easier + + align:start position:0% +squared okay just to make my life easier + + + align:start position:0% +squared okay just to make my life easier +right + + align:start position:0% +right + + + align:start position:0% +right +finally we will arrive this expression + + align:start position:0% +finally we will arrive this expression + + + align:start position:0% +finally we will arrive this expression +sheet a double dot plus gamma theta dot + + align:start position:0% +sheet a double dot plus gamma theta dot + + + align:start position:0% +sheet a double dot plus gamma theta dot +plus Omega 0 square theta and that is + + align:start position:0% +plus Omega 0 square theta and that is + + + align:start position:0% +plus Omega 0 square theta and that is +equal to 2 + + align:start position:0% + + + + align:start position:0% + +so what you can see from here is that we + + align:start position:0% +so what you can see from here is that we + + + align:start position:0% +so what you can see from here is that we +have actually arrived and derive the + + align:start position:0% +have actually arrived and derive the + + + align:start position:0% +have actually arrived and derive the +equation of motion + + align:start position:0% +equation of motion + + + align:start position:0% +equation of motion +okay we have described that this + + align:start position:0% +okay we have described that this + + + align:start position:0% +okay we have described that this +equation of motion and what is really + + align:start position:0% +equation of motion and what is really + + + align:start position:0% +equation of motion and what is really +the rest part of the world is actually + + align:start position:0% +the rest part of the world is actually + + + align:start position:0% +the rest part of the world is actually +ready to solve this equation of motion + + align:start position:0% +ready to solve this equation of motion + + + align:start position:0% +ready to solve this equation of motion +and you don't really have to solve it + + align:start position:0% +and you don't really have to solve it + + + align:start position:0% +and you don't really have to solve it +because you already get the result from + + align:start position:0% +because you already get the result from + + + align:start position:0% +because you already get the result from +1803 HD you will remember and we are + + align:start position:0% +1803 HD you will remember and we are + + + align:start position:0% +1803 HD you will remember and we are +going to discuss the result but before + + align:start position:0% +going to discuss the result but before + + + align:start position:0% +going to discuss the result but before +that before I really try to solve this + + align:start position:0% +that before I really try to solve this + + + align:start position:0% +that before I really try to solve this +equation I would like to take a vote + + align:start position:0% + + + + align:start position:0% + +okay so here I have two different two + + align:start position:0% +okay so here I have two different two + + + align:start position:0% +okay so here I have two different two +system okay they have equal amount of + + align:start position:0% +system okay they have equal amount of + + + align:start position:0% +system okay they have equal amount of +mass okay they are attached to a spring + + align:start position:0% +mass okay they are attached to a spring + + + align:start position:0% +mass okay they are attached to a spring +okay if you do the same equation motion + + align:start position:0% +okay if you do the same equation motion + + + align:start position:0% +okay if you do the same equation motion +simulation you will actually get exactly + + align:start position:0% +simulation you will actually get exactly + + + align:start position:0% +simulation you will actually get exactly +the same solution so it exactly the same + + align:start position:0% +the same solution so it exactly the same + + + align:start position:0% +the same solution so it exactly the same +equation of motion in in that form + + align:start position:0% +equation of motion in in that form + + + align:start position:0% +equation of motion in in that form +format okay so the form of the equation + + align:start position:0% +format okay so the form of the equation + + + align:start position:0% +format okay so the form of the equation +of motion will be the same between this + + align:start position:0% +of motion will be the same between this + + + align:start position:0% +of motion will be the same between this +system and that system okay I would like + + align:start position:0% +system and that system okay I would like + + + align:start position:0% +system and that system okay I would like +to ask you a question about the + + align:start position:0% +to ask you a question about the + + + align:start position:0% +to ask you a question about the +oscillation frequency so you can see + + align:start position:0% +oscillation frequency so you can see + + + align:start position:0% +oscillation frequency so you can see +that one one of them is as you have a + + align:start position:0% +that one one of them is as you have a + + + align:start position:0% +that one one of them is as you have a +mass like a point-like particle and the + + align:start position:0% +mass like a point-like particle and the + + + align:start position:0% +mass like a point-like particle and the +other one where the ahead okay what is + + align:start position:0% +other one where the ahead okay what is + + + align:start position:0% +other one where the ahead okay what is +going to happen is that this Mexican hat + + align:start position:0% +going to happen is that this Mexican hat + + + align:start position:0% +going to happen is that this Mexican hat +is going to be trying to push the air + + align:start position:0% +is going to be trying to push the air + + + align:start position:0% +is going to be trying to push the air +away right then you may sing okay this + + align:start position:0% +away right then you may sing okay this + + + align:start position:0% +away right then you may sing okay this +Mexican stream is not really very + + align:start position:0% +Mexican stream is not really very + + + align:start position:0% +Mexican stream is not really very +important therefore the oscillation + + align:start position:0% +important therefore the oscillation + + + align:start position:0% +important therefore the oscillation +frequency may be the same right how many + + align:start position:0% +frequency may be the same right how many + + + align:start position:0% +frequency may be the same right how many +of you think the oscillation frequency + + align:start position:0% +of you think the oscillation frequency + + + align:start position:0% +of you think the oscillation frequency +if I actually try to protect this two + + align:start position:0% +if I actually try to protect this two + + + align:start position:0% +if I actually try to protect this two +system will be the same help raise your + + align:start position:0% +system will be the same help raise your + + + align:start position:0% +system will be the same help raise your +hand one two three four five + + align:start position:0% + + + + align:start position:0% + +okay you have 11 so the Omega the + + align:start position:0% +okay you have 11 so the Omega the + + + align:start position:0% +okay you have 11 so the Omega the +predate Omega will be equal to Omega how + + align:start position:0% +predate Omega will be equal to Omega how + + + align:start position:0% +predate Omega will be equal to Omega how +many of you were seeing that okay + + align:start position:0% +many of you were seeing that okay + + + align:start position:0% +many of you were seeing that okay +because of this hat okay + + align:start position:0% +because of this hat okay + + + align:start position:0% +because of this hat okay +this is pushing this air away you know + + align:start position:0% +this is pushing this air away you know + + + align:start position:0% +this is pushing this air away you know +it's a lot of work to be done and + + align:start position:0% +it's a lot of work to be done and + + + align:start position:0% +it's a lot of work to be done and +therefore this is going to slow down the + + align:start position:0% +therefore this is going to slow down the + + + align:start position:0% +therefore this is going to slow down the +oscillation how many of you think that + + align:start position:0% +oscillation how many of you think that + + + align:start position:0% +oscillation how many of you think that +is going to happen one two three okay + + align:start position:0% +is going to happen one two three okay + + + align:start position:0% +is going to happen one two three okay +seventeen okay it may it may happen to + + align:start position:0% +seventeen okay it may it may happen to + + + align:start position:0% +seventeen okay it may it may happen to +you that you think this idea of know + + align:start position:0% +you that you think this idea of know + + + align:start position:0% +you that you think this idea of know +where Dena Headlee is really fashionable + + align:start position:0% +where Dena Headlee is really fashionable + + + align:start position:0% +where Dena Headlee is really fashionable +know therefore it got really exciting + + align:start position:0% +know therefore it got really exciting + + + align:start position:0% +know therefore it got really exciting +and also the faster cannot happen how + + align:start position:0% +and also the faster cannot happen how + + + align:start position:0% +and also the faster cannot happen how +many of you as you think that is going + + align:start position:0% +many of you as you think that is going + + + align:start position:0% +many of you as you think that is going +to happen okay one do you think so too + + align:start position:0% +to happen okay one do you think so too + + + align:start position:0% +to happen okay one do you think so too +very good we have to what what do you + + align:start position:0% +very good we have to what what do you + + + align:start position:0% +very good we have to what what do you +think what are the rest + + align:start position:0% +think what are the rest + + + align:start position:0% +think what are the rest +the only 30 of you as you think that is + + align:start position:0% +the only 30 of you as you think that is + + + align:start position:0% +the only 30 of you as you think that is +going to happen okay all the rest think + + align:start position:0% +going to happen okay all the rest think + + + align:start position:0% +going to happen okay all the rest think +all the rest of the class think that + + align:start position:0% +all the rest of the class think that + + + align:start position:0% +all the rest of the class think that +this is going to to disappear to the + + align:start position:0% +this is going to to disappear to the + + + align:start position:0% +this is going to to disappear to the +moon okay so that is as real opinion and + + align:start position:0% +moon okay so that is as real opinion and + + + align:start position:0% +moon okay so that is as real opinion and +we have completed the poll and what we + + align:start position:0% +we have completed the poll and what we + + + align:start position:0% +we have completed the poll and what we +are we are going to do is that we are + + align:start position:0% +are we are going to do is that we are + + + align:start position:0% +are we are going to do is that we are +going to solve this system and see what + + align:start position:0% +going to solve this system and see what + + + align:start position:0% +going to solve this system and see what +is going to happen and we will do the + + align:start position:0% +is going to happen and we will do the + + + align:start position:0% +is going to happen and we will do the +experiment in front of you okay all + + align:start position:0% +experiment in front of you okay all + + + align:start position:0% +experiment in front of you okay all +right so that's very nice so now we have + + align:start position:0% +right so that's very nice so now we have + + + align:start position:0% +right so that's very nice so now we have +this equation of motion and now I will + + align:start position:0% +this equation of motion and now I will + + + align:start position:0% +this equation of motion and now I will +pretend that I'm from the math + + align:start position:0% +pretend that I'm from the math + + + align:start position:0% +pretend that I'm from the math +department for a bit and help you guide + + align:start position:0% +department for a bit and help you guide + + + align:start position:0% +department for a bit and help you guide +you through the solution + + align:start position:0% +you through the solution + + + align:start position:0% +you through the solution +so now I can use this trick okay the + + align:start position:0% +so now I can use this trick okay the + + + align:start position:0% +so now I can use this trick okay the +CETA I can actually say Sita is actually + + align:start position:0% +CETA I can actually say Sita is actually + + + align:start position:0% +CETA I can actually say Sita is actually +the real part of the Z is a complex + + align:start position:0% +the real part of the Z is a complex + + + align:start position:0% +the real part of the Z is a complex +function and as we learned before the T + + align:start position:0% +function and as we learned before the T + + + align:start position:0% +function and as we learned before the T +and I assume that to be exponential I + + align:start position:0% +and I assume that to be exponential I + + + align:start position:0% +and I assume that to be exponential I +alpha so alpha is actually some kind of + + align:start position:0% +alpha so alpha is actually some kind of + + + align:start position:0% +alpha so alpha is actually some kind of +constant which we I I don't really know + + align:start position:0% +constant which we I I don't really know + + + align:start position:0% +constant which we I I don't really know +what is the constant yet okay now I can + + align:start position:0% +what is the constant yet okay now I can + + + align:start position:0% +what is the constant yet okay now I can +now actually write the equation of + + align:start position:0% +now actually write the equation of + + + align:start position:0% +now actually write the equation of +motion okay in the form of Z then + + align:start position:0% +motion okay in the form of Z then + + + align:start position:0% +motion okay in the form of Z then +basically what I get is Z double dot T + + align:start position:0% +basically what I get is Z double dot T + + + align:start position:0% +basically what I get is Z double dot T +plus gamma the dot T plus Omega 0 square + + align:start position:0% +plus gamma the dot T plus Omega 0 square + + + align:start position:0% +plus gamma the dot T plus Omega 0 square +the e of T and this is equal to 0 okay + + align:start position:0% +the e of T and this is equal to 0 okay + + + align:start position:0% +the e of T and this is equal to 0 okay +so remember explanation function cannot + + align:start position:0% +so remember explanation function cannot + + + align:start position:0% +so remember explanation function cannot +be killed by differentiation right + + align:start position:0% +be killed by differentiation right + + + align:start position:0% +be killed by differentiation right +therefore it's really convenient you can + + align:start position:0% +therefore it's really convenient you can + + + align:start position:0% +therefore it's really convenient you can +see from here now I can plug in this + + align:start position:0% +see from here now I can plug in this + + + align:start position:0% +see from here now I can plug in this +expression which I did some guests and + + align:start position:0% +expression which I did some guests and + + + align:start position:0% +expression which I did some guests and +two to this equation of motion then what + + align:start position:0% +two to this equation of motion then what + + + align:start position:0% +two to this equation of motion then what +I am going to get this minus alpha + + align:start position:0% +I am going to get this minus alpha + + + align:start position:0% +I am going to get this minus alpha +square okay because I you take I offer I + + align:start position:0% +square okay because I you take I offer I + + + align:start position:0% +square okay because I you take I offer I +have out of this exponential function + + align:start position:0% +have out of this exponential function + + + align:start position:0% +have out of this exponential function +right because you do to double + + align:start position:0% +right because you do to double + + + align:start position:0% +right because you do to double +differentiation okay so you get minus + + align:start position:0% +differentiation okay so you get minus + + + align:start position:0% +differentiation okay so you get minus +alpha square plus I gamma alpha right + + align:start position:0% +alpha square plus I gamma alpha right + + + align:start position:0% +alpha square plus I gamma alpha right +because this is only differentiate at + + align:start position:0% +because this is only differentiate at + + + align:start position:0% +because this is only differentiate at +one time plus Omega 0 Square and that is + + align:start position:0% +one time plus Omega 0 Square and that is + + + align:start position:0% +one time plus Omega 0 Square and that is +actually all those things as you is + + align:start position:0% +actually all those things as you is + + + align:start position:0% +actually all those things as you is +multiplying this exponential function + + align:start position:0% +multiplying this exponential function + + + align:start position:0% +multiplying this exponential function +exponential I have ax equal to zero okay + + align:start position:0% +exponential I have ax equal to zero okay + + + align:start position:0% +exponential I have ax equal to zero okay +so we will write this expression that is + + align:start position:0% +so we will write this expression that is + + + align:start position:0% +so we will write this expression that is +very nice and we also know that this + + align:start position:0% +very nice and we also know that this + + + align:start position:0% +very nice and we also know that this +expression is going to be bad it all the + + align:start position:0% +expression is going to be bad it all the + + + align:start position:0% +expression is going to be bad it all the +time no matter what + + align:start position:0% +time no matter what + + + align:start position:0% +time no matter what +what T you put in it should be bad right + + align:start position:0% +what T you put in it should be bad right + + + align:start position:0% +what T you put in it should be bad right +because this is the equation of motion + + align:start position:0% +because this is the equation of motion + + + align:start position:0% +because this is the equation of motion +and + + align:start position:0% +and + + + align:start position:0% +and +that we hope that this solution will + + align:start position:0% +that we hope that this solution will + + + align:start position:0% +that we hope that this solution will +survive this test right okay + + align:start position:0% +survive this test right okay + + + align:start position:0% +survive this test right okay +so I can easily conclude that this one + + align:start position:0% +so I can easily conclude that this one + + + align:start position:0% +so I can easily conclude that this one +is actually not equal to zero okay it + + align:start position:0% +is actually not equal to zero okay it + + + align:start position:0% +is actually not equal to zero okay it +can be some value nonzero so what is + + align:start position:0% +can be some value nonzero so what is + + + align:start position:0% +can be some value nonzero so what is +actually equal to zero this first term + + align:start position:0% +actually equal to zero this first term + + + align:start position:0% +actually equal to zero this first term +is actually equal to zero okay therefore + + align:start position:0% +is actually equal to zero okay therefore + + + align:start position:0% +is actually equal to zero okay therefore +I can now solve this equation minus + + align:start position:0% +I can now solve this equation minus + + + align:start position:0% +I can now solve this equation minus +alpha squared plus I gamma alpha plus + + align:start position:0% +alpha squared plus I gamma alpha plus + + + align:start position:0% +alpha squared plus I gamma alpha plus +Omega 0 square equal to zero I can solve + + align:start position:0% +Omega 0 square equal to zero I can solve + + + align:start position:0% +Omega 0 square equal to zero I can solve +it ok if I do that then I will get alpha + + align:start position:0% +it ok if I do that then I will get alpha + + + align:start position:0% +it ok if I do that then I will get alpha +is equal to I gamma plus minus square + + align:start position:0% +is equal to I gamma plus minus square + + + align:start position:0% +is equal to I gamma plus minus square +root of 4 Omega 0 square minus gamma + + align:start position:0% +root of 4 Omega 0 square minus gamma + + + align:start position:0% +root of 4 Omega 0 square minus gamma +square divided by 2 this is actually a + + align:start position:0% +square divided by 2 this is actually a + + + align:start position:0% +square divided by 2 this is actually a +second-order polynomial and you can + + align:start position:0% +second-order polynomial and you can + + + align:start position:0% +second-order polynomial and you can +actually add that this issue equal to 0 + + align:start position:0% +actually add that this issue equal to 0 + + + align:start position:0% +actually add that this issue equal to 0 +therefore you can actually solve in Z + + align:start position:0% +therefore you can actually solve in Z + + + align:start position:0% +therefore you can actually solve in Z +and this is actually the solution and I + + align:start position:0% +and this is actually the solution and I + + + align:start position:0% +and this is actually the solution and I +can write it down you know slightly + + align:start position:0% +can write it down you know slightly + + + align:start position:0% +can write it down you know slightly +different form I gamma over 2 plus minus + + align:start position:0% +different form I gamma over 2 plus minus + + + align:start position:0% +different form I gamma over 2 plus minus +square root of Omega 0 square minus + + align:start position:0% +square root of Omega 0 square minus + + + align:start position:0% +square root of Omega 0 square minus +gamma square over 4 okay + + align:start position:0% +gamma square over 4 okay + + + align:start position:0% +gamma square over 4 okay +any questions so far and not going too + + align:start position:0% +any questions so far and not going too + + + align:start position:0% +any questions so far and not going too +fast no everything so ok ok + + align:start position:0% + + + + align:start position:0% + +so you can see that half is equal to + + align:start position:0% +so you can see that half is equal to + + + align:start position:0% +so you can see that half is equal to +this expression and I would like to + + align:start position:0% +this expression and I would like to + + + align:start position:0% +this expression and I would like to +consider a situation where Omega zero is + + align:start position:0% +consider a situation where Omega zero is + + + align:start position:0% +consider a situation where Omega zero is +much much larger than gamma okay + + align:start position:0% +much much larger than gamma okay + + + align:start position:0% +much much larger than gamma okay +that means just a reminder of what is + + align:start position:0% +that means just a reminder of what is + + + align:start position:0% +that means just a reminder of what is +gamma okay + + align:start position:0% +gamma okay + + + align:start position:0% +gamma okay +maybe you got already a bit confused + + align:start position:0% +maybe you got already a bit confused + + + align:start position:0% +maybe you got already a bit confused +what is gamma gamma is related to the + + align:start position:0% +what is gamma gamma is related to the + + + align:start position:0% +what is gamma gamma is related to the +strength of the drag force right it's + + align:start position:0% +strength of the drag force right it's + + + align:start position:0% +strength of the drag force right it's +actually three P over N squared okay P + + align:start position:0% +actually three P over N squared okay P + + + align:start position:0% +actually three P over N squared okay P +is actually giving you the portion okay + + align:start position:0% +is actually giving you the portion okay + + + align:start position:0% +is actually giving you the portion okay +it's actually determining the size of + + align:start position:0% +it's actually determining the size of + + + align:start position:0% +it's actually determining the size of +the drag force okay so I would like to + + align:start position:0% +the drag force okay so I would like to + + + align:start position:0% +the drag force okay so I would like to +consider a situation the first situation + + align:start position:0% +consider a situation the first situation + + + align:start position:0% +consider a situation the first situation +is if Omega 0 square is larger than + + align:start position:0% +is if Omega 0 square is larger than + + + align:start position:0% +is if Omega 0 square is larger than +gamma square over 4 okay so it not limit + + align:start position:0% +gamma square over 4 okay so it not limit + + + align:start position:0% +gamma square over 4 okay so it not limit +it so in that case the drag force okay + + align:start position:0% +it so in that case the drag force okay + + + align:start position:0% +it so in that case the drag force okay +it is small okay it's not huge okay + + align:start position:0% +it is small okay it's not huge okay + + + align:start position:0% +it is small okay it's not huge okay +small okay if that is the case this is + + align:start position:0% +small okay if that is the case this is + + + align:start position:0% +small okay if that is the case this is +actually real right because Omega 0 + + align:start position:0% +actually real right because Omega 0 + + + align:start position:0% +actually real right because Omega 0 +square is larger than gamma square over + + align:start position:0% +square is larger than gamma square over + + + align:start position:0% +square is larger than gamma square over +4 therefore this is real okay so now I + + align:start position:0% +4 therefore this is real okay so now I + + + align:start position:0% +4 therefore this is real okay so now I +can actually define Omega square define + + align:start position:0% +can actually define Omega square define + + + align:start position:0% +can actually define Omega square define +that as Omega 0 square minus gamma + + align:start position:0% +that as Omega 0 square minus gamma + + + align:start position:0% +that as Omega 0 square minus gamma +square over 4 ok and this will become + + align:start position:0% +square over 4 ok and this will become + + + align:start position:0% +square over 4 ok and this will become +and this will become hi gamma over 2 + + align:start position:0% +and this will become hi gamma over 2 + + + align:start position:0% +and this will become hi gamma over 2 +plus minus Omega okay so that means I + + align:start position:0% +plus minus Omega okay so that means I + + + align:start position:0% +plus minus Omega okay so that means I +will have two solutions coming from this + + align:start position:0% +will have two solutions coming from this + + + align:start position:0% +will have two solutions coming from this +exercise the pass of T is equal to + + align:start position:0% +exercise the pass of T is equal to + + + align:start position:0% +exercise the pass of T is equal to +exponential minus gamma over 2 T + + align:start position:0% +exponential minus gamma over 2 T + + + align:start position:0% +exponential minus gamma over 2 T +exponential + + align:start position:0% +exponential + + + align:start position:0% +exponential +I Omega okay and the - the second + + align:start position:0% +I Omega okay and the - the second + + + align:start position:0% +I Omega okay and the - the second +solution okay if I take one of the plus + + align:start position:0% +solution okay if I take one of the plus + + + align:start position:0% +solution okay if I take one of the plus +sign that was a minus sign solution then + + align:start position:0% +sign that was a minus sign solution then + + + align:start position:0% +sign that was a minus sign solution then +the second solution will be explanation + + align:start position:0% +the second solution will be explanation + + + align:start position:0% +the second solution will be explanation +minus I gamma over 2t explanation - hi + + align:start position:0% +minus I gamma over 2t explanation - hi + + + align:start position:0% +minus I gamma over 2t explanation - hi +oh my gosh okay any questions so far + + align:start position:0% + + + + align:start position:0% + +okay so we would like to go back to Sita + + align:start position:0% +okay so we would like to go back to Sita + + + align:start position:0% +okay so we would like to go back to Sita +right so so what would be the Sita so + + align:start position:0% +right so so what would be the Sita so + + + align:start position:0% +right so so what would be the Sita so +that means I will have a theta 1 of T + + align:start position:0% +that means I will have a theta 1 of T + + + align:start position:0% +that means I will have a theta 1 of T +which is actually taking the real part + + align:start position:0% +which is actually taking the real part + + + align:start position:0% +which is actually taking the real part +so I see the price maybe okay + + align:start position:0% +so I see the price maybe okay + + + align:start position:0% +so I see the price maybe okay +taking the real part of the Z press and + + align:start position:0% +taking the real part of the Z press and + + + align:start position:0% +taking the real part of the Z press and +now we'll give you exponential minus + + align:start position:0% +now we'll give you exponential minus + + + align:start position:0% +now we'll give you exponential minus +gamma over 2t cosine Omega okay I'm just + + align:start position:0% +gamma over 2t cosine Omega okay I'm just + + + align:start position:0% +gamma over 2t cosine Omega okay I'm just +plugging in the solution to this + + align:start position:0% +plugging in the solution to this + + + align:start position:0% +plugging in the solution to this +equation okay theta minus T will be + + align:start position:0% +equation okay theta minus T will be + + + align:start position:0% +equation okay theta minus T will be +equal to exponential and come over to T + + align:start position:0% +equal to exponential and come over to T + + + align:start position:0% +equal to exponential and come over to T +sine Omega T okay finally the full + + align:start position:0% +sine Omega T okay finally the full + + + align:start position:0% +sine Omega T okay finally the full +solution of theta of T will be a linear + + align:start position:0% +solution of theta of T will be a linear + + + align:start position:0% +solution of theta of T will be a linear +combination of this two solution right + + align:start position:0% +combination of this two solution right + + + align:start position:0% +combination of this two solution right +therefore you will get set of t equal to + + align:start position:0% +therefore you will get set of t equal to + + + align:start position:0% +therefore you will get set of t equal to +exponential minus gamma over 2t a is + + align:start position:0% +exponential minus gamma over 2t a is + + + align:start position:0% +exponential minus gamma over 2t a is +some kind of constant times cosine Omega + + align:start position:0% +some kind of constant times cosine Omega + + + align:start position:0% +some kind of constant times cosine Omega +T plus P sine Omega T okay + + align:start position:0% +T plus P sine Omega T okay + + + align:start position:0% +T plus P sine Omega T okay +and of course from the last time as you + + align:start position:0% +and of course from the last time as you + + + align:start position:0% +and of course from the last time as you +we know that this can also be written as + + align:start position:0% +we know that this can also be written as + + + align:start position:0% +we know that this can also be written as +a cosine Omega T plus five + + align:start position:0% +a cosine Omega T plus five + + + align:start position:0% +a cosine Omega T plus five +okay any questions so far + + align:start position:0% + + + + align:start position:0% + +okay very good so we have actually + + align:start position:0% +okay very good so we have actually + + + align:start position:0% +okay very good so we have actually +already solved this equation and of + + align:start position:0% +already solved this equation and of + + + align:start position:0% +already solved this equation and of +course we can actually practice a back + + align:start position:0% +course we can actually practice a back + + + align:start position:0% +course we can actually practice a back +into this equation of motion and you + + align:start position:0% +into this equation of motion and you + + + align:start position:0% +into this equation of motion and you +will see that it really works and I'm + + align:start position:0% +will see that it really works and I'm + + + align:start position:0% +will see that it really works and I'm +not going to do that now but you can + + align:start position:0% +not going to do that now but you can + + + align:start position:0% +not going to do that now but you can +easily go back home and check and you + + align:start position:0% +easily go back home and check and you + + + align:start position:0% +easily go back home and check and you +will be deep me it works and also at the + + align:start position:0% +will be deep me it works and also at the + + + align:start position:0% +will be deep me it works and also at the +same time you got to undetermined + + align:start position:0% +same time you got to undetermined + + + align:start position:0% +same time you got to undetermined +constants since this is a second order + + align:start position:0% +constants since this is a second order + + + align:start position:0% +constants since this is a second order +differential equation therefore ha this + + align:start position:0% +differential equation therefore ha this + + + align:start position:0% +differential equation therefore ha this +thing as you works have two arbitrary + + align:start position:0% +thing as you works have two arbitrary + + + align:start position:0% +thing as you works have two arbitrary +constant therefore that is actually one + + align:start position:0% +constant therefore that is actually one + + + align:start position:0% +constant therefore that is actually one +and the only one solution in a universe + + align:start position:0% +and the only one solution in a universe + + + align:start position:0% +and the only one solution in a universe +which satisfy the equation of motion or + + align:start position:0% +which satisfy the equation of motion or + + + align:start position:0% +which satisfy the equation of motion or +to satisfy that equation equation + + align:start position:0% +to satisfy that equation equation + + + align:start position:0% +to satisfy that equation equation +differential equation okay so this thing + + align:start position:0% +differential equation okay so this thing + + + align:start position:0% +differential equation okay so this thing +actually have dramatical consequence the + + align:start position:0% +actually have dramatical consequence the + + + align:start position:0% +actually have dramatical consequence the +first thing which we learn is that as a + + align:start position:0% +first thing which we learn is that as a + + + align:start position:0% +first thing which we learn is that as a +function of time what is going to happen + + align:start position:0% +function of time what is going to happen + + + align:start position:0% +function of time what is going to happen +okay + + align:start position:0% +okay + + + align:start position:0% +okay +the amplitude is now becoming + + align:start position:0% +the amplitude is now becoming + + + align:start position:0% +the amplitude is now becoming +exponential minus gamma over 2t times a + + align:start position:0% +exponential minus gamma over 2t times a + + + align:start position:0% +exponential minus gamma over 2t times a +this is actually the amplitude the + + align:start position:0% +this is actually the amplitude the + + + align:start position:0% +this is actually the amplitude the +amplitude is decreasing exponentially so + + align:start position:0% +amplitude is decreasing exponentially so + + + align:start position:0% +amplitude is decreasing exponentially so +that is actually the first partition + + align:start position:0% +that is actually the first partition + + + align:start position:0% +that is actually the first partition +coming from this exercise okay the + + align:start position:0% +coming from this exercise okay the + + + align:start position:0% +coming from this exercise okay the +second prediction is that this C is + + align:start position:0% +second prediction is that this C is + + + align:start position:0% +second prediction is that this C is +still oscillating because we've got the + + align:start position:0% +still oscillating because we've got the + + + align:start position:0% +still oscillating because we've got the +cosine Omega T plus Phi there you see so + + align:start position:0% +cosine Omega T plus Phi there you see so + + + align:start position:0% +cosine Omega T plus Phi there you see so +the resulting motion is going to be like + + align:start position:0% +the resulting motion is going to be like + + + align:start position:0% +the resulting motion is going to be like +going up and down I'll be done and got + + align:start position:0% +going up and down I'll be done and got + + + align:start position:0% +going up and down I'll be done and got +tired + + align:start position:0% +tired + + + align:start position:0% +tired +therefore the amplitude because small + + align:start position:0% +therefore the amplitude because small + + + align:start position:0% +therefore the amplitude because small +Ernst + + align:start position:0% +Ernst + + + align:start position:0% +Ernst +and modern but it's never zero right + + align:start position:0% +and modern but it's never zero right + + + align:start position:0% +and modern but it's never zero right +it's never a zero okay it's actually + + align:start position:0% +it's never a zero okay it's actually + + + align:start position:0% +it's never a zero okay it's actually +going to be a living down so small I + + align:start position:0% +going to be a living down so small I + + + align:start position:0% +going to be a living down so small I +couldn't see it but it's still + + align:start position:0% +couldn't see it but it's still + + + align:start position:0% +couldn't see it but it's still +oscillating okay + + align:start position:0% + + + + align:start position:0% + +finally we actually have also the answer + + align:start position:0% +finally we actually have also the answer + + + align:start position:0% +finally we actually have also the answer +to the original question we post okay so + + align:start position:0% +to the original question we post okay so + + + align:start position:0% +to the original question we post okay so +now you can see that the oscillation + + align:start position:0% +now you can see that the oscillation + + + align:start position:0% +now you can see that the oscillation +frequency is omega okay originally + + align:start position:0% +frequency is omega okay originally + + + align:start position:0% +frequency is omega okay originally +before we introduced the drag force + + align:start position:0% +before we introduced the drag force + + + align:start position:0% +before we introduced the drag force +Omega 0 which is the oscillation + + align:start position:0% +Omega 0 which is the oscillation + + + align:start position:0% +Omega 0 which is the oscillation +frequency it should be like your + + align:start position:0% +frequency it should be like your + + + align:start position:0% +frequency it should be like your +frequency is a square root of 3G over 2l + + align:start position:0% +frequency is a square root of 3G over 2l + + + align:start position:0% +frequency is a square root of 3G over 2l +and you can see that the Omega okay that + + align:start position:0% +and you can see that the Omega okay that + + + align:start position:0% +and you can see that the Omega okay that +the new Omega the oscillation frequency + + align:start position:0% +the new Omega the oscillation frequency + + + align:start position:0% +the new Omega the oscillation frequency +with drag force essentially Omega 0 + + align:start position:0% +with drag force essentially Omega 0 + + + align:start position:0% +with drag force essentially Omega 0 +square square root of this Omega 0 + + align:start position:0% +square square root of this Omega 0 + + + align:start position:0% +square square root of this Omega 0 +square minus gamma squared over 4 so + + align:start position:0% +square minus gamma squared over 4 so + + + align:start position:0% +square minus gamma squared over 4 so +that what this tells she tells us is + + align:start position:0% +that what this tells she tells us is + + + align:start position:0% +that what this tells she tells us is +that this is going to be smaller right + + align:start position:0% +that this is going to be smaller right + + + align:start position:0% +that this is going to be smaller right +because of the drag force okay so that's + + align:start position:0% +because of the drag force okay so that's + + + align:start position:0% +because of the drag force okay so that's +the prediction ok let's do the + + align:start position:0% +the prediction ok let's do the + + + align:start position:0% +the prediction ok let's do the +experiment and see what is going to + + align:start position:0% +experiment and see what is going to + + + align:start position:0% +experiment and see what is going to +happen so let's take a look at this two + + align:start position:0% +happen so let's take a look at this two + + + align:start position:0% +happen so let's take a look at this two +system they have the identical mass + + align:start position:0% +system they have the identical mass + + + align:start position:0% +system they have the identical mass +which our instructor taking her + + align:start position:0% +which our instructor taking her + + + align:start position:0% +which our instructor taking her +instructor H we kept for the prepare + + align:start position:0% +instructor H we kept for the prepare + + + align:start position:0% +instructor H we kept for the prepare +okay they have the same mass even though + + align:start position:0% +okay they have the same mass even though + + + align:start position:0% +okay they have the same mass even though +one is actually do go Tiffany the other + + align:start position:0% +one is actually do go Tiffany the other + + + align:start position:0% +one is actually do go Tiffany the other +one looks normal okay now what I'm going + + align:start position:0% +one looks normal okay now what I'm going + + + align:start position:0% +one looks normal okay now what I'm going +to do is to really try and and see which + + align:start position:0% +to do is to really try and and see which + + + align:start position:0% +to do is to really try and and see which +one is actually isolating faster okay so + + align:start position:0% +one is actually isolating faster okay so + + + align:start position:0% +one is actually isolating faster okay so +let's see I drew this then at the same + + align:start position:0% +let's see I drew this then at the same + + + align:start position:0% +let's see I drew this then at the same +time and you can see that originally + + align:start position:0% +time and you can see that originally + + + align:start position:0% +time and you can see that originally +they seem to be oscillating at the same + + align:start position:0% +they seem to be oscillating at the same + + + align:start position:0% +they seem to be oscillating at the same +frequency but you can see very clearly + + align:start position:0% +frequency but you can see very clearly + + + align:start position:0% +frequency but you can see very clearly +that the one with the head is actually + + align:start position:0% +that the one with the head is actually + + + align:start position:0% +that the one with the head is actually +oscillating slower okay so you can see + + align:start position:0% +oscillating slower okay so you can see + + + align:start position:0% +oscillating slower okay so you can see +that okay seventeen of you actually have + + align:start position:0% +that okay seventeen of you actually have + + + align:start position:0% +that okay seventeen of you actually have +the correct answer gather courage and + + align:start position:0% +the correct answer gather courage and + + + align:start position:0% +the correct answer gather courage and +and the most important thing is that you + + align:start position:0% +and the most important thing is that you + + + align:start position:0% +and the most important thing is that you +can see that this simple mask actually + + align:start position:0% +can see that this simple mask actually + + + align:start position:0% +can see that this simple mask actually +describe and predict what is going to + + align:start position:0% +describe and predict what is going to + + + align:start position:0% +describe and predict what is going to +happen in my little experiment so that + + align:start position:0% +happen in my little experiment so that + + + align:start position:0% +happen in my little experiment so that +is actually really cool and I think it's + + align:start position:0% +is actually really cool and I think it's + + + align:start position:0% +is actually really cool and I think it's +time to take a little break and they + + align:start position:0% +time to take a little break and they + + + align:start position:0% +time to take a little break and they +will come come back and and look at + + align:start position:0% +will come come back and and look at + + + align:start position:0% +will come come back and and look at +other solutions and of course you are + + align:start position:0% +other solutions and of course you are + + + align:start position:0% +other solutions and of course you are +welcome to come to the front to pray + + align:start position:0% +welcome to come to the front to pray + + + align:start position:0% +welcome to come to the front to pray +with those demonstrations + + align:start position:0% + + + + align:start position:0% + +so there are two small issues which were + + align:start position:0% +so there are two small issues which were + + + align:start position:0% +so there are two small issues which were +raised by during the break so the first + + align:start position:0% +raised by during the break so the first + + + align:start position:0% +raised by during the break so the first +one is that if you actually calculate + + align:start position:0% +one is that if you actually calculate + + + align:start position:0% +one is that if you actually calculate +the torque okay + + align:start position:0% +the torque okay + + + align:start position:0% +the torque okay +from this fund this equation so I made a + + align:start position:0% +from this fund this equation so I made a + + + align:start position:0% +from this fund this equation so I made a +mistake + + align:start position:0% +mistake + + + align:start position:0% +mistake +the R vector should be actually pointing + + align:start position:0% +the R vector should be actually pointing + + + align:start position:0% +the R vector should be actually pointing +from the nail to the center of mass okay + + align:start position:0% +from the nail to the center of mass okay + + + align:start position:0% +from the nail to the center of mass okay +so I think that's a trivial a mistake so + + align:start position:0% +so I think that's a trivial a mistake so + + + align:start position:0% +so I think that's a trivial a mistake so +if you do this okay + + align:start position:0% +if you do this okay + + + align:start position:0% +if you do this okay +then you can get you a care today the + + align:start position:0% +then you can get you a care today the + + + align:start position:0% +then you can get you a care today the +tau equal to R cross F then you actually + + align:start position:0% +tau equal to R cross F then you actually + + + align:start position:0% +tau equal to R cross F then you actually +get this minus sign okay so so if I if I + + align:start position:0% +get this minus sign okay so so if I if I + + + align:start position:0% +get this minus sign okay so so if I if I +make a mistake and pointing toward the + + align:start position:0% +make a mistake and pointing toward the + + + align:start position:0% +make a mistake and pointing toward the +nail okay then you will get no minus + + align:start position:0% +nail okay then you will get no minus + + + align:start position:0% +nail okay then you will get no minus +sign okay they're not really work okay + + align:start position:0% +sign okay they're not really work okay + + + align:start position:0% +sign okay they're not really work okay +so so very good I'm very happy that you + + align:start position:0% +so so very good I'm very happy that you + + + align:start position:0% +so so very good I'm very happy that you +are actually paying very much attention + + align:start position:0% +are actually paying very much attention + + + align:start position:0% +are actually paying very much attention +to capture those the the second issue is + + align:start position:0% +to capture those the the second issue is + + + align:start position:0% +to capture those the the second issue is +that okay so now I'm saying that okay + + align:start position:0% +that okay so now I'm saying that okay + + + align:start position:0% +that okay so now I'm saying that okay +now I have the solution in the complex + + align:start position:0% +now I have the solution in the complex + + + align:start position:0% +now I have the solution in the complex +form format so I can have a G+ and I + + align:start position:0% +form format so I can have a G+ and I + + + align:start position:0% +form format so I can have a G+ and I +have the Z - okay + + align:start position:0% +have the Z - okay + + + align:start position:0% +have the Z - okay +and then I would like to go to the real + + align:start position:0% +and then I would like to go to the real + + + align:start position:0% +and then I would like to go to the real +world + + align:start position:0% +world + + + align:start position:0% +world +right because imaginary thing is + + align:start position:0% +right because imaginary thing is + + + align:start position:0% +right because imaginary thing is +actually hidden in some kind of you know + + align:start position:0% +actually hidden in some kind of you know + + + align:start position:0% +actually hidden in some kind of you know +motion in the actual dimension and etc I + + align:start position:0% +motion in the actual dimension and etc I + + + align:start position:0% +motion in the actual dimension and etc I +would like to go back to reality okay + + align:start position:0% +would like to go back to reality okay + + + align:start position:0% +would like to go back to reality okay +and and what I said in the class is that + + align:start position:0% +and and what I said in the class is that + + + align:start position:0% +and and what I said in the class is that +I take a real part of one of the + + align:start position:0% +I take a real part of one of the + + + align:start position:0% +I take a real part of one of the +solution and I can also take the real + + align:start position:0% +solution and I can also take the real + + + align:start position:0% +solution and I can also take the real +part of I times one of the solution but + + align:start position:0% +part of I times one of the solution but + + + align:start position:0% +part of I times one of the solution but +of course you can also do this by doing + + align:start position:0% +of course you can also do this by doing + + + align:start position:0% +of course you can also do this by doing +a linear combination of the solution + + align:start position:0% +a linear combination of the solution + + + align:start position:0% +a linear combination of the solution +right as we actually discussed last time + + align:start position:0% +right as we actually discussed last time + + + align:start position:0% +right as we actually discussed last time +linear combination of the solutions is + + align:start position:0% +linear combination of the solutions is + + + align:start position:0% +linear combination of the solutions is +also a solution to this the same + + align:start position:0% +also a solution to this the same + + + align:start position:0% +also a solution to this the same +equation of motion right since this one + + align:start position:0% +equation of motion right since this one + + + align:start position:0% +equation of motion right since this one +is a linear therefore what I actually do + + align:start position:0% +is a linear therefore what I actually do + + + align:start position:0% +is a linear therefore what I actually do +is actually to to sum the two solution + + align:start position:0% +is actually to to sum the two solution + + + align:start position:0% +is actually to to sum the two solution +the press and D - and / - or actually I + + align:start position:0% +the press and D - and / - or actually I + + + align:start position:0% +the press and D - and / - or actually I +attended to the two minus I over 2 times + + align:start position:0% +attended to the two minus I over 2 times + + + align:start position:0% +attended to the two minus I over 2 times +the price - the the - okay then I can + + align:start position:0% +the price - the the - okay then I can + + + align:start position:0% +the price - the the - okay then I can +also extract this sign + + align:start position:0% +also extract this sign + + + align:start position:0% +also extract this sign +here okay so that is that should be the + + align:start position:0% +here okay so that is that should be the + + + align:start position:0% +here okay so that is that should be the +correct explanation of the two solution + + align:start position:0% +correct explanation of the two solution + + + align:start position:0% +correct explanation of the two solution +in real axis okay any questions so far + + align:start position:0% +in real axis okay any questions so far + + + align:start position:0% +in real axis okay any questions so far +thank you very much for protection + + align:start position:0% +thank you very much for protection + + + align:start position:0% +thank you very much for protection +during those okay so now you can see + + align:start position:0% +during those okay so now you can see + + + align:start position:0% +during those okay so now you can see +that we have been discussing the + + align:start position:0% +that we have been discussing the + + + align:start position:0% +that we have been discussing the +equation of motion of this functional + + align:start position:0% +equation of motion of this functional + + + align:start position:0% +equation of motion of this functional +form and the one thing which is really + + align:start position:0% +form and the one thing which is really + + + align:start position:0% +form and the one thing which is really +interesting is that the solution when we + + align:start position:0% +interesting is that the solution when we + + + align:start position:0% +interesting is that the solution when we +take small track force limit actually we + + align:start position:0% +take small track force limit actually we + + + align:start position:0% +take small track force limit actually we +arrive a beautiful solution looks like + + align:start position:0% +arrive a beautiful solution looks like + + + align:start position:0% +arrive a beautiful solution looks like +this a exponential minus gamma over 2t + + align:start position:0% +this a exponential minus gamma over 2t + + + align:start position:0% +this a exponential minus gamma over 2t +cosine Omega T plus Phi + + align:start position:0% +cosine Omega T plus Phi + + + align:start position:0% +cosine Omega T plus Phi +that I should predict the oscillation + + align:start position:0% +that I should predict the oscillation + + + align:start position:0% +that I should predict the oscillation +okay at the same time he also says that + + align:start position:0% +okay at the same time he also says that + + + align:start position:0% +okay at the same time he also says that +the amplitude is actually going to drop + + align:start position:0% +the amplitude is actually going to drop + + + align:start position:0% +the amplitude is actually going to drop +exponentially but never zero okay + + align:start position:0% +exponentially but never zero okay + + + align:start position:0% +exponentially but never zero okay +finally we also know that this solution + + align:start position:0% +finally we also know that this solution + + + align:start position:0% +finally we also know that this solution +actually tells us that if we have a + + align:start position:0% +actually tells us that if we have a + + + align:start position:0% +actually tells us that if we have a +spring mass system oscillating up and + + align:start position:0% +spring mass system oscillating up and + + + align:start position:0% +spring mass system oscillating up and +down if we have a rod like what we + + align:start position:0% +down if we have a rod like what we + + + align:start position:0% +down if we have a rod like what we +actually solving in in a class this + + align:start position:0% +actually solving in in a class this + + + align:start position:0% +actually solving in in a class this +object is going to pass through zero the + + align:start position:0% +object is going to pass through zero the + + + align:start position:0% +object is going to pass through zero the +equilibrium position infinite number of + + align:start position:0% +equilibrium position infinite number of + + + align:start position:0% +equilibrium position infinite number of +times right because the the cosine is + + align:start position:0% +times right because the the cosine is + + + align:start position:0% +times right because the the cosine is +always there therefore although the mp2 + + align:start position:0% +always there therefore although the mp2 + + + align:start position:0% +always there therefore although the mp2 +become very small they still oscillating + + align:start position:0% +become very small they still oscillating + + + align:start position:0% +become very small they still oscillating +forever until the end of the universe + + align:start position:0% +forever until the end of the universe + + + align:start position:0% +forever until the end of the universe +okay all right so that's actually what + + align:start position:0% +okay all right so that's actually what + + + align:start position:0% +okay all right so that's actually what +we have learned and also one thing which + + align:start position:0% +we have learned and also one thing which + + + align:start position:0% +we have learned and also one thing which +we learned that time is that simple + + align:start position:0% +we learned that time is that simple + + + align:start position:0% +we learned that time is that simple +harmonic motion okay like this one which + + align:start position:0% +harmonic motion okay like this one which + + + align:start position:0% +harmonic motion okay like this one which +was shown here or this one which is a + + align:start position:0% +was shown here or this one which is a + + + align:start position:0% +was shown here or this one which is a +mass oscillating back and forth on the + + align:start position:0% +mass oscillating back and forth on the + + + align:start position:0% +mass oscillating back and forth on the +track essentially just a projection of a + + align:start position:0% +track essentially just a projection of a + + + align:start position:0% +track essentially just a projection of a +circular motion right in the complex + + align:start position:0% +circular motion right in the complex + + + align:start position:0% +circular motion right in the complex +plane okay and what we are really seeing + + align:start position:0% +plane okay and what we are really seeing + + + align:start position:0% +plane okay and what we are really seeing +here in front of in front of you is + + align:start position:0% +here in front of in front of you is + + + align:start position:0% +here in front of in front of you is +actually a projection to the real axis + + align:start position:0% +actually a projection to the real axis + + + align:start position:0% +actually a projection to the real axis +okay so that's actually really + + align:start position:0% +okay so that's actually really + + + align:start position:0% +okay so that's actually really +remarkable + + align:start position:0% +remarkable + + + align:start position:0% +remarkable +result and the beautiful picture and of + + align:start position:0% +result and the beautiful picture and of + + + align:start position:0% +result and the beautiful picture and of +course we can actually also practice the + + align:start position:0% +course we can actually also practice the + + + align:start position:0% +course we can actually also practice the +solution with Tempe so what is actually + + align:start position:0% +solution with Tempe so what is actually + + + align:start position:0% +solution with Tempe so what is actually +the picture in this language in in this + + align:start position:0% +the picture in this language in in this + + + align:start position:0% +the picture in this language in in this +exactly the same language if we actually + + align:start position:0% +exactly the same language if we actually + + + align:start position:0% +exactly the same language if we actually +follow the locus and basically what you + + align:start position:0% +follow the locus and basically what you + + + align:start position:0% +follow the locus and basically what you +are going to see is that this thing as + + align:start position:0% +are going to see is that this thing as + + + align:start position:0% +are going to see is that this thing as +you spiral okay and the amplitude is + + align:start position:0% +you spiral okay and the amplitude is + + + align:start position:0% +you spiral okay and the amplitude is +actually getting smaller and smaller and + + align:start position:0% +actually getting smaller and smaller and + + + align:start position:0% +actually getting smaller and smaller and +they sucked into this black hole in the + + align:start position:0% +they sucked into this black hole in the + + + align:start position:0% +they sucked into this black hole in the +zero zero okay so you can see that now + + align:start position:0% +zero zero okay so you can see that now + + + align:start position:0% +zero zero okay so you can see that now +the the the picture looks as if there is + + align:start position:0% +the the the picture looks as if there is + + + align:start position:0% +the the the picture looks as if there is +something really rotating in the complex + + align:start position:0% +something really rotating in the complex + + + align:start position:0% +something really rotating in the complex +plane and they essentially approaching + + align:start position:0% +plane and they essentially approaching + + + align:start position:0% +plane and they essentially approaching +zero because the amplitude is casually + + align:start position:0% +zero because the amplitude is casually + + + align:start position:0% +zero because the amplitude is casually +getting smaller and smaller but this + + align:start position:0% +getting smaller and smaller but this + + + align:start position:0% +getting smaller and smaller but this +whole thing is still rotating okay okay + + align:start position:0% +whole thing is still rotating okay okay + + + align:start position:0% +whole thing is still rotating okay okay +that's pretty nice + + align:start position:0% +that's pretty nice + + + align:start position:0% +that's pretty nice +alright so now this is actually a + + align:start position:0% +alright so now this is actually a + + + align:start position:0% +alright so now this is actually a +special case when we actually assume + + align:start position:0% +special case when we actually assume + + + align:start position:0% +special case when we actually assume +that gamma is actually pretty small so + + align:start position:0% +that gamma is actually pretty small so + + + align:start position:0% +that gamma is actually pretty small so +you have very small tract force okay so + + align:start position:0% +you have very small tract force okay so + + + align:start position:0% +you have very small tract force okay so +that's actually check what will happen + + align:start position:0% +that's actually check what will happen + + + align:start position:0% +that's actually check what will happen +if I now start to increase the drag + + align:start position:0% +if I now start to increase the drag + + + align:start position:0% +if I now start to increase the drag +force make this hat larger larger and + + align:start position:0% +force make this hat larger larger and + + + align:start position:0% +force make this hat larger larger and +larger okay introducing more and more + + align:start position:0% +larger okay introducing more and more + + + align:start position:0% +larger okay introducing more and more +track okay what is going to happen okay + + align:start position:0% +track okay what is going to happen okay + + + align:start position:0% +track okay what is going to happen okay +so now I consider the situation the + + align:start position:0% +so now I consider the situation the + + + align:start position:0% +so now I consider the situation the +second situation Omega 0 square equal to + + align:start position:0% +second situation Omega 0 square equal to + + + align:start position:0% +second situation Omega 0 square equal to +gamma square over 4 okay okay so when + + align:start position:0% +gamma square over 4 okay okay so when + + + align:start position:0% +gamma square over 4 okay okay so when +when the gamma is very small what we see + + align:start position:0% +when the gamma is very small what we see + + + align:start position:0% +when the gamma is very small what we see +is that this is actually under damped + + align:start position:0% +is that this is actually under damped + + + align:start position:0% +is that this is actually under damped +right so so the damping is really small + + align:start position:0% +right so so the damping is really small + + + align:start position:0% +right so so the damping is really small +but if I increase the gamma to a + + align:start position:0% +but if I increase the gamma to a + + + align:start position:0% +but if I increase the gamma to a +critical value now Omega 0 square happen + + align:start position:0% +critical value now Omega 0 square happen + + + align:start position:0% +critical value now Omega 0 square happen +to be equal to gamma square over 4 okay + + align:start position:0% +to be equal to gamma square over 4 okay + + + align:start position:0% +to be equal to gamma square over 4 okay +I call this critically + + align:start position:0% +I call this critically + + + align:start position:0% +I call this critically +damn oscillate + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so what does that mean that means Omega + + align:start position:0% +so what does that mean that means Omega + + + align:start position:0% +so what does that mean that means Omega +is equal to zero + + align:start position:0% +is equal to zero + + + align:start position:0% +is equal to zero +you see this is our definition of Omega + + align:start position:0% +you see this is our definition of Omega + + + align:start position:0% +you see this is our definition of Omega +right if Omega zero equal square equal + + align:start position:0% +right if Omega zero equal square equal + + + align:start position:0% +right if Omega zero equal square equal +to gamma square over 4 then Omega is + + align:start position:0% +to gamma square over 4 then Omega is + + + align:start position:0% +to gamma square over 4 then Omega is +equal to zero + + align:start position:0% +equal to zero + + + align:start position:0% +equal to zero +the artisans with the critical moment + + align:start position:0% +the artisans with the critical moment + + + align:start position:0% +the artisans with the critical moment +the cistern stop oscillating okay so it + + align:start position:0% +the cistern stop oscillating okay so it + + + align:start position:0% +the cistern stop oscillating okay so it +is not absolutely any more okay so now I + + align:start position:0% +is not absolutely any more okay so now I + + + align:start position:0% +is not absolutely any more okay so now I +can actually start from from the + + align:start position:0% +can actually start from from the + + + align:start position:0% +can actually start from from the +solution where I obtained from one one + + align:start position:0% +solution where I obtained from one one + + + align:start position:0% +solution where I obtained from one one +okay and I can actually how you make + + align:start position:0% +okay and I can actually how you make + + + align:start position:0% +okay and I can actually how you make +make use of this this two solution + + align:start position:0% +make use of this this two solution + + + align:start position:0% +make use of this this two solution +cheetara's in the city minus theta plus + + align:start position:0% +cheetara's in the city minus theta plus + + + align:start position:0% +cheetara's in the city minus theta plus +P will be equal to exponential minus + + align:start position:0% +P will be equal to exponential minus + + + align:start position:0% +P will be equal to exponential minus +gamma over 2t cosine Omega T when Omega + + align:start position:0% +gamma over 2t cosine Omega T when Omega + + + align:start position:0% +gamma over 2t cosine Omega T when Omega +goes to 0 okay what is going to happen + + align:start position:0% +goes to 0 okay what is going to happen + + + align:start position:0% +goes to 0 okay what is going to happen +is that this is actually becoming which + + align:start position:0% +is that this is actually becoming which + + + align:start position:0% +is that this is actually becoming which +value anybody know if Omega C 0 what is + + align:start position:0% +value anybody know if Omega C 0 what is + + + align:start position:0% +value anybody know if Omega C 0 what is +going to happen one yeah okay one right + + align:start position:0% +going to happen one yeah okay one right + + + align:start position:0% +going to happen one yeah okay one right +so that will give me exponential minus + + align:start position:0% +so that will give me exponential minus + + + align:start position:0% +so that will give me exponential minus +gamma over 2t see top minus T okay I can + + align:start position:0% +gamma over 2t see top minus T okay I can + + + align:start position:0% +gamma over 2t see top minus T okay I can +do the same trick and see what will + + align:start position:0% +do the same trick and see what will + + + align:start position:0% +do the same trick and see what will +happen so I take sin theta minus T okay + + align:start position:0% +happen so I take sin theta minus T okay + + + align:start position:0% +happen so I take sin theta minus T okay +which is as you obtained it from the + + align:start position:0% +which is as you obtained it from the + + + align:start position:0% +which is as you obtained it from the +exercise number one when we discuss on + + align:start position:0% +exercise number one when we discuss on + + + align:start position:0% +exercise number one when we discuss on +the template system then you in case you + + align:start position:0% +the template system then you in case you + + + align:start position:0% +the template system then you in case you +get exponential minus gamma over 2t sine + + align:start position:0% +get exponential minus gamma over 2t sine + + + align:start position:0% +get exponential minus gamma over 2t sine +Omega T Omega goes to 0 I should I get 0 + + align:start position:0% +Omega T Omega goes to 0 I should I get 0 + + + align:start position:0% +Omega T Omega goes to 0 I should I get 0 +it's time okay so that don't really + + align:start position:0% +it's time okay so that don't really + + + align:start position:0% +it's time okay so that don't really +right because if I have a solution which + + align:start position:0% +right because if I have a solution which + + + align:start position:0% +right because if I have a solution which +is zero then it's not describing + + align:start position:0% +is zero then it's not describing + + + align:start position:0% +is zero then it's not describing +anything right I can always add zero to + + align:start position:0% +anything right I can always add zero to + + + align:start position:0% +anything right I can always add zero to +to the solution but that help you okay + + align:start position:0% +to the solution but that help you okay + + + align:start position:0% +to the solution but that help you okay +so instead of taking the limit of this + + align:start position:0% +so instead of taking the limit of this + + + align:start position:0% +so instead of taking the limit of this +this function actually we choose to + + align:start position:0% +this function actually we choose to + + + align:start position:0% +this function actually we choose to +actually to Sita minus T divided by + + align:start position:0% +actually to Sita minus T divided by + + + align:start position:0% +actually to Sita minus T divided by +Omega and that we actually make this + + align:start position:0% +Omega and that we actually make this + + + align:start position:0% +Omega and that we actually make this +approaching Omega approaching zero then + + align:start position:0% +approaching Omega approaching zero then + + + align:start position:0% +approaching Omega approaching zero then +basically I get exponential minus gamma + + align:start position:0% +basically I get exponential minus gamma + + + align:start position:0% +basically I get exponential minus gamma +over 2t sine Omega T divided by Omega + + align:start position:0% +over 2t sine Omega T divided by Omega + + + align:start position:0% +over 2t sine Omega T divided by Omega +okay if I have this approaching Omega + + align:start position:0% +okay if I have this approaching Omega + + + align:start position:0% +okay if I have this approaching Omega +approaching to 0 and this is HD roughly + + align:start position:0% +approaching to 0 and this is HD roughly + + + align:start position:0% +approaching to 0 and this is HD roughly +just explanation of minus gamma over 2t + + align:start position:0% +just explanation of minus gamma over 2t + + + align:start position:0% +just explanation of minus gamma over 2t +Omega T Omega and this is actually + + align:start position:0% +Omega T Omega and this is actually + + + align:start position:0% +Omega T Omega and this is actually +keeping you ki times exponential minus + + align:start position:0% +keeping you ki times exponential minus + + + align:start position:0% +keeping you ki times exponential minus +gamma over 2t any questions so far + + align:start position:0% + + + + align:start position:0% + +at this one yeah so it should be okay + + align:start position:0% +at this one yeah so it should be okay + + + align:start position:0% +at this one yeah so it should be okay +yeah yes this is a negative sign + + align:start position:0% +yeah yes this is a negative sign + + + align:start position:0% +yeah yes this is a negative sign +yes okay any other questions okay so you + + align:start position:0% +yes okay any other questions okay so you + + + align:start position:0% +yes okay any other questions okay so you +can see that now I arrived to solution + + align:start position:0% +can see that now I arrived to solution + + + align:start position:0% +can see that now I arrived to solution +one is actually proportional to + + align:start position:0% +one is actually proportional to + + + align:start position:0% +one is actually proportional to +exponential minus gamma over 2t the + + align:start position:0% +exponential minus gamma over 2t the + + + align:start position:0% +exponential minus gamma over 2t the +other one is actually proportional to T + + align:start position:0% +other one is actually proportional to T + + + align:start position:0% +other one is actually proportional to T +times exponential minus gamma over 2t + + align:start position:0% +times exponential minus gamma over 2t + + + align:start position:0% +times exponential minus gamma over 2t +okay so you can see that the cosine or + + align:start position:0% +okay so you can see that the cosine or + + + align:start position:0% +okay so you can see that the cosine or +sine turn disappeared right so that + + align:start position:0% +sine turn disappeared right so that + + + align:start position:0% +sine turn disappeared right so that +means you were never oscillating okay so + + align:start position:0% +means you were never oscillating okay so + + + align:start position:0% +means you were never oscillating okay so +this is actually what we see in this + + align:start position:0% +this is actually what we see in this + + + align:start position:0% +this is actually what we see in this +slide this so-called critically damped + + align:start position:0% +slide this so-called critically damped + + + align:start position:0% +slide this so-called critically damped +okay when actually Omega zero squared is + + align:start position:0% +okay when actually Omega zero squared is + + + align:start position:0% +okay when actually Omega zero squared is +equal to gamma square over 4 and you can + + align:start position:0% +equal to gamma square over 4 and you can + + + align:start position:0% +equal to gamma square over 4 and you can +see that what is going to happen is that + + align:start position:0% +see that what is going to happen is that + + + align:start position:0% +see that what is going to happen is that +this mass okay or this rod is going to + + align:start position:0% +this mass okay or this rod is going to + + + align:start position:0% +this mass okay or this rod is going to +pass 0 only one time at most okay and it + + align:start position:0% +pass 0 only one time at most okay and it + + + align:start position:0% +pass 0 only one time at most okay and it +could actually never pass 0 if you + + align:start position:0% +could actually never pass 0 if you + + + align:start position:0% +could actually never pass 0 if you +actually set up the initial condition + + align:start position:0% +actually set up the initial condition + + + align:start position:0% +actually set up the initial condition +correcting okay so so one thing which I + + align:start position:0% +correcting okay so so one thing which I + + + align:start position:0% +correcting okay so so one thing which I +can do is I shoot this mass really + + align:start position:0% +can do is I shoot this mass really + + + align:start position:0% +can do is I shoot this mass really +really very forcefully so that I have a + + align:start position:0% +really very forcefully so that I have a + + + align:start position:0% +really very forcefully so that I have a +very large initial velocity and what it + + align:start position:0% +very large initial velocity and what it + + + align:start position:0% +very large initial velocity and what it +really is going to do like the + + align:start position:0% +really is going to do like the + + + align:start position:0% +really is going to do like the +right-hand side diagram + + align:start position:0% +right-hand side diagram + + + align:start position:0% +right-hand side diagram +oh you will overshoot the row a bit then + + align:start position:0% +oh you will overshoot the row a bit then + + + align:start position:0% +oh you will overshoot the row a bit then +close back it almost like exponentially + + align:start position:0% +close back it almost like exponentially + + + align:start position:0% +close back it almost like exponentially +okay so at most you can only pass to + + align:start position:0% +okay so at most you can only pass to + + + align:start position:0% +okay so at most you can only pass to +zero one time if you do this kind of + + align:start position:0% +zero one time if you do this kind of + + + align:start position:0% +zero one time if you do this kind of +initial condition okay so that is + + align:start position:0% +initial condition okay so that is + + + align:start position:0% +initial condition okay so that is +actually pretty interesting and there + + align:start position:0% +actually pretty interesting and there + + + align:start position:0% +actually pretty interesting and there +are practical application of this poncho + + align:start position:0% +are practical application of this poncho + + + align:start position:0% +are practical application of this poncho +it is a solution actually so for example + + align:start position:0% +it is a solution actually so for example + + + align:start position:0% +it is a solution actually so for example +we have the door closed + + align:start position:0% +we have the door closed + + + align:start position:0% +we have the door closed +so it's also here right the toad clothes + + align:start position:0% +so it's also here right the toad clothes + + + align:start position:0% +so it's also here right the toad clothes +you would like to have the tour go back + + align:start position:0% +you would like to have the tour go back + + + align:start position:0% +you would like to have the tour go back +to the original clothes the mode the + + align:start position:0% +to the original clothes the mode the + + + align:start position:0% +to the original clothes the mode the +position of equilibrium position is + + align:start position:0% +position of equilibrium position is + + + align:start position:0% +position of equilibrium position is +really fast ok so what you can do is + + align:start position:0% +really fast ok so what you can do is + + + align:start position:0% +really fast ok so what you can do is +really design this toad course so that + + align:start position:0% +really design this toad course so that + + + align:start position:0% +really design this toad course so that +issue is actually match with critical + + align:start position:0% +issue is actually match with critical + + + align:start position:0% +issue is actually match with critical +tempter situation ok a good condition so + + align:start position:0% +tempter situation ok a good condition so + + + align:start position:0% +tempter situation ok a good condition so +that actually you go back to zero really + + align:start position:0% +that actually you go back to zero really + + + align:start position:0% +that actually you go back to zero really +quick ok any questions ok so now what we + + align:start position:0% +quick ok any questions ok so now what we + + + align:start position:0% +quick ok any questions ok so now what we +could do is that instead of having a + + align:start position:0% +could do is that instead of having a + + + align:start position:0% +could do is that instead of having a +very small drag force were worse a + + align:start position:0% +very small drag force were worse a + + + align:start position:0% +very small drag force were worse a +slightly larger track for so that + + align:start position:0% +slightly larger track for so that + + + align:start position:0% +slightly larger track for so that +actually reach critical tempt situation + + align:start position:0% +actually reach critical tempt situation + + + align:start position:0% +actually reach critical tempt situation +what we could do is that we put the + + align:start position:0% +what we could do is that we put the + + + align:start position:0% +what we could do is that we put the +whole system into water right the end of + + align:start position:0% +whole system into water right the end of + + + align:start position:0% +whole system into water right the end of +track force will be very big okay and we + + align:start position:0% +track force will be very big okay and we + + + align:start position:0% +track force will be very big okay and we +would like to see what is going to + + align:start position:0% +would like to see what is going to + + + align:start position:0% +would like to see what is going to +happen ok so in this case is the third + + align:start position:0% +happen ok so in this case is the third + + + align:start position:0% +happen ok so in this case is the third +situation ok the third situation is that + + align:start position:0% +situation ok the third situation is that + + + align:start position:0% +situation ok the third situation is that +Omega 0 square is actually smoother than + + align:start position:0% +Omega 0 square is actually smoother than + + + align:start position:0% +Omega 0 square is actually smoother than +gamma square over 4 so you have huge + + align:start position:0% +gamma square over 4 so you have huge + + + align:start position:0% +gamma square over 4 so you have huge +drag force okay so that will give you a + + align:start position:0% +drag force okay so that will give you a + + + align:start position:0% +drag force okay so that will give you a +situation which is called over damped + + align:start position:0% + + + + align:start position:0% + +oscillator + + align:start position:0% + + + + align:start position:0% + +now I have again alpha is equal to I + + align:start position:0% +now I have again alpha is equal to I + + + align:start position:0% +now I have again alpha is equal to I +gamma over 2 + + align:start position:0% +gamma over 2 + + + align:start position:0% +gamma over 2 +okay price minus square root of Omega 0 + + align:start position:0% +okay price minus square root of Omega 0 + + + align:start position:0% +okay price minus square root of Omega 0 +square minus gamma square over 4 right + + align:start position:0% +square minus gamma square over 4 right + + + align:start position:0% +square minus gamma square over 4 right +I'm just copying from here okay and that + + align:start position:0% +I'm just copying from here okay and that + + + align:start position:0% +I'm just copying from here okay and that +will be equal to I I can take out the I + + align:start position:0% +will be equal to I I can take out the I + + + align:start position:0% +will be equal to I I can take out the I +ok gamma over 2 plus minus square root + + align:start position:0% +ok gamma over 2 plus minus square root + + + align:start position:0% +ok gamma over 2 plus minus square root +of gamma squared over 4 minus Omega 0 + + align:start position:0% +of gamma squared over 4 minus Omega 0 + + + align:start position:0% +of gamma squared over 4 minus Omega 0 +square now I can easily define gamma + + align:start position:0% +square now I can easily define gamma + + + align:start position:0% +square now I can easily define gamma +plus minus equal to gamma over 2 plus + + align:start position:0% +plus minus equal to gamma over 2 plus + + + align:start position:0% +plus minus equal to gamma over 2 plus +minus square root of gamma square over 4 + + align:start position:0% +minus square root of gamma square over 4 + + + align:start position:0% +minus square root of gamma square over 4 +minus Omega 0 square ok then basically + + align:start position:0% +minus Omega 0 square ok then basically + + + align:start position:0% +minus Omega 0 square ok then basically +the solution okay I this is actually now + + align:start position:0% +the solution okay I this is actually now + + + align:start position:0% +the solution okay I this is actually now +I already have the solution so basically + + align:start position:0% +I already have the solution so basically + + + align:start position:0% +I already have the solution so basically +the two solution will be looking like + + align:start position:0% +the two solution will be looking like + + + align:start position:0% +the two solution will be looking like +this Sita of T will be equal to a plus + + align:start position:0% +this Sita of T will be equal to a plus + + + align:start position:0% +this Sita of T will be equal to a plus +some kind of constant exponential minus + + align:start position:0% +some kind of constant exponential minus + + + align:start position:0% +some kind of constant exponential minus +gamma plus T plus a minus exponential + + align:start position:0% +gamma plus T plus a minus exponential + + + align:start position:0% +gamma plus T plus a minus exponential +minus gamma minus T ok because this is + + align:start position:0% +minus gamma minus T ok because this is + + + align:start position:0% +minus gamma minus T ok because this is +actually becoming already ok + + align:start position:0% +actually becoming already ok + + + align:start position:0% +actually becoming already ok +so alpha is actually I times gamma plus + + align:start position:0% +so alpha is actually I times gamma plus + + + align:start position:0% +so alpha is actually I times gamma plus +minus right there for you if you put the + + align:start position:0% +minus right there for you if you put the + + + align:start position:0% +minus right there for you if you put the +back into this then basically what you + + align:start position:0% +back into this then basically what you + + + align:start position:0% +back into this then basically what you +are getting is explanation plus gamma + + align:start position:0% +are getting is explanation plus gamma + + + align:start position:0% +are getting is explanation plus gamma +exponential minus gamma plus T or + + align:start position:0% +exponential minus gamma plus T or + + + align:start position:0% +exponential minus gamma plus T or +explanation of minus gamma minus T ok so + + align:start position:0% +explanation of minus gamma minus T ok so + + + align:start position:0% +explanation of minus gamma minus T ok so +that's already a real function and + + align:start position:0% +that's already a real function and + + + align:start position:0% +that's already a real function and +linear combination of these two solution + + align:start position:0% +linear combination of these two solution + + + align:start position:0% +linear combination of these two solution +is our final four solution to the + + align:start position:0% +is our final four solution to the + + + align:start position:0% +is our final four solution to the +equation of motion + + align:start position:0% +equation of motion + + + align:start position:0% +equation of motion +okay again what we are going to see is + + align:start position:0% +okay again what we are going to see is + + + align:start position:0% +okay again what we are going to see is +that this is actually the drag force is + + align:start position:0% +that this is actually the drag force is + + + align:start position:0% +that this is actually the drag force is +huge I just throw the whole system into + + align:start position:0% +huge I just throw the whole system into + + + align:start position:0% +huge I just throw the whole system into +water and the water is really stopped + + align:start position:0% +water and the water is really stopped + + + align:start position:0% +water and the water is really stopped +trying to stop the oscillation really + + align:start position:0% +trying to stop the oscillation really + + + align:start position:0% +trying to stop the oscillation really +very much therefore you can see that huh + + align:start position:0% +very much therefore you can see that huh + + + align:start position:0% +very much therefore you can see that huh +again I don't have any oscillation okay + + align:start position:0% +again I don't have any oscillation okay + + + align:start position:0% +again I don't have any oscillation okay +if I am very very strong start this + + align:start position:0% +if I am very very strong start this + + + align:start position:0% +if I am very very strong start this +thing 3d 3d start the initial velocity + + align:start position:0% +thing 3d 3d start the initial velocity + + + align:start position:0% +thing 3d 3d start the initial velocity +or initial angular velocity really high + + align:start position:0% +or initial angular velocity really high + + + align:start position:0% +or initial angular velocity really high +you have I have actually give a huge + + align:start position:0% +you have I have actually give a huge + + + align:start position:0% +you have I have actually give a huge +amount of energy into this system then + + align:start position:0% +amount of energy into this system then + + + align:start position:0% +amount of energy into this system then +at most again I can actually have that + + align:start position:0% +at most again I can actually have that + + + align:start position:0% +at most again I can actually have that +system to pass through the equilibrium + + align:start position:0% +system to pass through the equilibrium + + + align:start position:0% +system to pass through the equilibrium +position only one time then this whole + + align:start position:0% +position only one time then this whole + + + align:start position:0% +position only one time then this whole +this system will slow the grid paper + + align:start position:0% +this system will slow the grid paper + + + align:start position:0% +this system will slow the grid paper +okay because the gamma because of the + + align:start position:0% +okay because the gamma because of the + + + align:start position:0% +okay because the gamma because of the +exponential function we see here the + + align:start position:0% +exponential function we see here the + + + align:start position:0% +exponential function we see here the +amplitude is going to be decaying + + align:start position:0% +amplitude is going to be decaying + + + align:start position:0% +amplitude is going to be decaying +exponentially okay any questions so + + align:start position:0% +exponentially okay any questions so + + + align:start position:0% +exponentially okay any questions so +that's actually do a quick demonstration + + align:start position:0% +that's actually do a quick demonstration + + + align:start position:0% +that's actually do a quick demonstration +here okay so here this is actually the + + align:start position:0% +here okay so here this is actually the + + + align:start position:0% +here okay so here this is actually the +original bit little pore here metal one + + align:start position:0% +original bit little pore here metal one + + + align:start position:0% +original bit little pore here metal one +which is actually you can see that this + + align:start position:0% +which is actually you can see that this + + + align:start position:0% +which is actually you can see that this +is going to go back and forth really + + align:start position:0% +is going to go back and forth really + + + align:start position:0% +is going to go back and forth really +nicely and you can see that because of + + align:start position:0% +nicely and you can see that because of + + + align:start position:0% +nicely and you can see that because of +the friction okay actually the amplitude + + align:start position:0% +the friction okay actually the amplitude + + + align:start position:0% +the friction okay actually the amplitude +is becoming smaller and smaller okay so + + align:start position:0% +is becoming smaller and smaller okay so + + + align:start position:0% +is becoming smaller and smaller okay so +that actually match with this situation + + align:start position:0% +that actually match with this situation + + + align:start position:0% +that actually match with this situation +right so it's actually under damped the + + align:start position:0% +right so it's actually under damped the + + + align:start position:0% +right so it's actually under damped the +situation this ball is going to if in + + align:start position:0% +situation this ball is going to if in + + + align:start position:0% +situation this ball is going to if in +idealized situation it's going to go + + align:start position:0% +idealized situation it's going to go + + + align:start position:0% +idealized situation it's going to go +through zero infinite number of times + + align:start position:0% +through zero infinite number of times + + + align:start position:0% +through zero infinite number of times +okay so now what I'm going to do is how + + align:start position:0% +okay so now what I'm going to do is how + + + align:start position:0% +okay so now what I'm going to do is how +I change this ball to something which is + + align:start position:0% +I change this ball to something which is + + + align:start position:0% +I change this ball to something which is +different okay this is actually made of + + align:start position:0% +different okay this is actually made of + + + align:start position:0% +different okay this is actually made of +Mac Magna knee okay and let's see what + + align:start position:0% +Mac Magna knee okay and let's see what + + + align:start position:0% +Mac Magna knee okay and let's see what +is going to happen + + align:start position:0% +is going to happen + + + align:start position:0% +is going to happen +so now you can see that because this is + + align:start position:0% +so now you can see that because this is + + + align:start position:0% +so now you can see that because this is +actually made of magnet + + align:start position:0% +actually made of magnet + + + align:start position:0% +actually made of magnet +therefore the drag force will be kolosso + + align:start position:0% +therefore the drag force will be kolosso + + + align:start position:0% +therefore the drag force will be kolosso +will be very very big and let's see what + + align:start position:0% +will be very very big and let's see what + + + align:start position:0% +will be very very big and let's see what +happen you see that that the track force + + align:start position:0% +happen you see that that the track force + + + align:start position:0% +happen you see that that the track force +is huge + + align:start position:0% +is huge + + + align:start position:0% +is huge +therefore you see I put it here so that + + align:start position:0% +therefore you see I put it here so that + + + align:start position:0% +therefore you see I put it here so that +ie has big initial velocity the only + + align:start position:0% +ie has big initial velocity the only + + + align:start position:0% +ie has big initial velocity the only +path to zero once right + + align:start position:0% +path to zero once right + + + align:start position:0% +path to zero once right +of course it now is actually approaching + + align:start position:0% +of course it now is actually approaching + + + align:start position:0% +of course it now is actually approaching +the zero already really slowly + + align:start position:0% +the zero already really slowly + + + align:start position:0% +the zero already really slowly +exponentially but it's not zero okay so + + align:start position:0% +exponentially but it's not zero okay so + + + align:start position:0% +exponentially but it's not zero okay so +you know the pass through the zero you + + align:start position:0% +you know the pass through the zero you + + + align:start position:0% +you know the pass through the zero you +feel free diplomats only once + + align:start position:0% +feel free diplomats only once + + + align:start position:0% +feel free diplomats only once +okay just to show that this is a real + + align:start position:0% +okay just to show that this is a real + + + align:start position:0% +okay just to show that this is a real +deal okay right oh I'm not trying to + + align:start position:0% +deal okay right oh I'm not trying to + + + align:start position:0% +deal okay right oh I'm not trying to +destroy the whole cause ruin okay okay + + align:start position:0% +destroy the whole cause ruin okay okay + + + align:start position:0% +destroy the whole cause ruin okay okay +so you can actually pray with this + + align:start position:0% +so you can actually pray with this + + + align:start position:0% +so you can actually pray with this +after we initial lecture okay I would + + align:start position:0% +after we initial lecture okay I would + + + align:start position:0% +after we initial lecture okay I would +like to ask you a question after we + + align:start position:0% +like to ask you a question after we + + + align:start position:0% +like to ask you a question after we +learn this front is a lecture okay there + + align:start position:0% +learn this front is a lecture okay there + + + align:start position:0% +learn this front is a lecture okay there +are three situation under damped + + align:start position:0% +are three situation under damped + + + align:start position:0% +are three situation under damped +critically damped and the over damped + + align:start position:0% +critically damped and the over damped + + + align:start position:0% +critically damped and the over damped +okay I would like to ask you two + + align:start position:0% +okay I would like to ask you two + + + align:start position:0% +okay I would like to ask you two +questions the first one is through this + + align:start position:0% +questions the first one is through this + + + align:start position:0% +questions the first one is through this +demonstration okay so now I have a + + align:start position:0% +demonstration okay so now I have a + + + align:start position:0% +demonstration okay so now I have a +system which is nicely constructed I + + align:start position:0% +system which is nicely constructed I + + + align:start position:0% +system which is nicely constructed I +hope you can see it okay that's it and + + align:start position:0% +hope you can see it okay that's it and + + + align:start position:0% +hope you can see it okay that's it and +this system is made of a torsional + + align:start position:0% +this system is made of a torsional + + + align:start position:0% +this system is made of a torsional +spring and also there's a pad here which + + align:start position:0% +spring and also there's a pad here which + + + align:start position:0% +spring and also there's a pad here which +is connected to a spring okay if I + + align:start position:0% +is connected to a spring okay if I + + + align:start position:0% +is connected to a spring okay if I +actually perturb this thing it's going + + align:start position:0% +actually perturb this thing it's going + + + align:start position:0% +actually perturb this thing it's going +to be oscillating back and forth before + + align:start position:0% +to be oscillating back and forth before + + + align:start position:0% +to be oscillating back and forth before +I turn on the power so that you know the + + align:start position:0% +I turn on the power so that you know the + + + align:start position:0% +I turn on the power so that you know the +lower part is actually you have magnet + + align:start position:0% +lower part is actually you have magnet + + + align:start position:0% +lower part is actually you have magnet +okay + + align:start position:0% +okay + + + align:start position:0% +okay +is not turned on yet okay and this + + align:start position:0% +is not turned on yet okay and this + + + align:start position:0% +is not turned on yet okay and this +magnet is going to provide a drag force + + align:start position:0% +magnet is going to provide a drag force + + + align:start position:0% +magnet is going to provide a drag force +to actually change the behavior of this + + align:start position:0% +to actually change the behavior of this + + + align:start position:0% +to actually change the behavior of this +system okay so you can see that before I + + align:start position:0% +system okay so you can see that before I + + + align:start position:0% +system okay so you can see that before I +turn on the magnetic field the whole + + align:start position:0% +turn on the magnetic field the whole + + + align:start position:0% +turn on the magnetic field the whole +system is actually oscillating back and + + align:start position:0% +system is actually oscillating back and + + + align:start position:0% +system is actually oscillating back and +forth really nicely as we predict smoke + + align:start position:0% +forth really nicely as we predict smoke + + + align:start position:0% +forth really nicely as we predict smoke +amplitude vibration is harmonic + + align:start position:0% +amplitude vibration is harmonic + + + align:start position:0% +amplitude vibration is harmonic +oscillation okay so that's very nice so + + align:start position:0% +oscillation okay so that's very nice so + + + align:start position:0% +oscillation okay so that's very nice so +now what I'm going to do is to turn on + + align:start position:0% +now what I'm going to do is to turn on + + + align:start position:0% +now what I'm going to do is to turn on +the power and see what is going to + + align:start position:0% +the power and see what is going to + + + align:start position:0% +the power and see what is going to +happen after I turn on the power there's + + align:start position:0% +happen after I turn on the power there's + + + align:start position:0% +happen after I turn on the power there's +a there's a electric field okay and and + + align:start position:0% +a there's a electric field okay and and + + + align:start position:0% +a there's a electric field okay and and +this is you're going to be okay so the + + align:start position:0% +this is you're going to be okay so the + + + align:start position:0% +this is you're going to be okay so the +magnet when the magnetic field is I + + align:start position:0% +magnet when the magnetic field is I + + + align:start position:0% +magnet when the magnetic field is I +should turn down therefore this is + + align:start position:0% +should turn down therefore this is + + + align:start position:0% +should turn down therefore this is +actually acting like a drag force a + + align:start position:0% +actually acting like a drag force a + + + align:start position:0% +actually acting like a drag force a +tooth to this system okay so that's + + align:start position:0% +tooth to this system okay so that's + + + align:start position:0% +tooth to this system okay so that's +actually see what is going to happen now + + align:start position:0% +actually see what is going to happen now + + + align:start position:0% +actually see what is going to happen now +I drew this this makes this the behavior + + align:start position:0% +I drew this this makes this the behavior + + + align:start position:0% +I drew this this makes this the behavior +of the system looks like this you first + + align:start position:0% +of the system looks like this you first + + + align:start position:0% +of the system looks like this you first +oscillate and then it stops so the + + align:start position:0% +oscillate and then it stops so the + + + align:start position:0% +oscillate and then it stops so the +question is is this critical tent under + + align:start position:0% +question is is this critical tent under + + + align:start position:0% +question is is this critical tent under +damped over over damped system anybody + + align:start position:0% +damped over over damped system anybody + + + align:start position:0% +damped over over damped system anybody +knows yeah yes this is under damped how + + align:start position:0% +knows yeah yes this is under damped how + + + align:start position:0% +knows yeah yes this is under damped how +do I see that that is because when I do + + align:start position:0% +do I see that that is because when I do + + + align:start position:0% +do I see that that is because when I do +this experiment you will pass through + + align:start position:0% +this experiment you will pass through + + + align:start position:0% +this experiment you will pass through +zeros multiple times + + align:start position:0% +zeros multiple times + + + align:start position:0% +zeros multiple times +therefore there are oscillations trying + + align:start position:0% +therefore there are oscillations trying + + + align:start position:0% +therefore there are oscillations trying +into prey + + align:start position:0% +into prey + + + align:start position:0% +into prey +therefore I can conclude that the drag + + align:start position:0% +therefore I can conclude that the drag + + + align:start position:0% +therefore I can conclude that the drag +force is not large enough so that is + + align:start position:0% +force is not large enough so that is + + + align:start position:0% +force is not large enough so that is +actually a ton on the template situation + + align:start position:0% +actually a ton on the template situation + + + align:start position:0% +actually a ton on the template situation +okay and the next time we are going to + + align:start position:0% +okay and the next time we are going to + + + align:start position:0% +okay and the next time we are going to +drive this system I have a second + + align:start position:0% +drive this system I have a second + + + align:start position:0% +drive this system I have a second +question for you so now your friends + + align:start position:0% +question for you so now your friends + + + align:start position:0% +question for you so now your friends +know that you take took arrow 3 + + align:start position:0% +know that you take took arrow 3 + + + align:start position:0% +know that you take took arrow 3 +therefore they were wondering if you can + + align:start position:0% +therefore they were wondering if you can + + + align:start position:0% +therefore they were wondering if you can +actually design a car suspension system + + align:start position:0% +actually design a car suspension system + + + align:start position:0% +actually design a car suspension system +okay to see if you can actually make the + + align:start position:0% +okay to see if you can actually make the + + + align:start position:0% +okay to see if you can actually make the +design for them when you design this car + + align:start position:0% +design for them when you design this car + + + align:start position:0% +design for them when you design this car +which + + align:start position:0% +which + + + align:start position:0% +which +condition will you consider to set up + + align:start position:0% +condition will you consider to set up + + + align:start position:0% +condition will you consider to set up +the car where you set it up as a under + + align:start position:0% +the car where you set it up as a under + + + align:start position:0% +the car where you set it up as a under +damped critically damped or over damped + + align:start position:0% +damped critically damped or over damped + + + align:start position:0% +damped critically damped or over damped +how many of you actually think you + + align:start position:0% +how many of you actually think you + + + align:start position:0% +how many of you actually think you +should be under damped no nobody + + align:start position:0% +should be under damped no nobody + + + align:start position:0% +should be under damped no nobody +how many of you as you think it should + + align:start position:0% +how many of you as you think it should + + + align:start position:0% +how many of you as you think it should +be over damped one two three four okay + + align:start position:0% +be over damped one two three four okay + + + align:start position:0% +be over damped one two three four okay +how many of you as you think you should + + align:start position:0% +how many of you as you think you should + + + align:start position:0% +how many of you as you think you should +be critically damped okay but jority of + + align:start position:0% +be critically damped okay but jority of + + + align:start position:0% +be critically damped okay but jority of +you think that should be the correct + + align:start position:0% +you think that should be the correct + + + align:start position:0% +you think that should be the correct +design so if you have the car design as + + align:start position:0% +design so if you have the car design as + + + align:start position:0% +design so if you have the car design as +an under damped situation then when you + + align:start position:0% +an under damped situation then when you + + + align:start position:0% +an under damped situation then when you +drive the car you are going to have very + + align:start position:0% +drive the car you are going to have very + + + align:start position:0% +drive the car you are going to have very +funny style you're going to have this + + align:start position:0% +funny style you're going to have this + + + align:start position:0% +funny style you're going to have this +now this is the style so that your car + + align:start position:0% +now this is the style so that your car + + + align:start position:0% +now this is the style so that your car +is going to be oscillating all the time + + align:start position:0% +is going to be oscillating all the time + + + align:start position:0% +is going to be oscillating all the time +okay because it's going to be there and + + align:start position:0% +okay because it's going to be there and + + + align:start position:0% +okay because it's going to be there and +it's really tempting really slowly okay + + align:start position:0% +it's really tempting really slowly okay + + + align:start position:0% +it's really tempting really slowly okay +if you design that to be over damped it + + align:start position:0% +if you design that to be over damped it + + + align:start position:0% +if you design that to be over damped it +would be become very bumpy right so so + + align:start position:0% +would be become very bumpy right so so + + + align:start position:0% +would be become very bumpy right so so +let's take a limit of infinitely large + + align:start position:0% +let's take a limit of infinitely large + + + align:start position:0% +let's take a limit of infinitely large +drug force constant okay then it's like + + align:start position:0% +drug force constant okay then it's like + + + align:start position:0% +drug force constant okay then it's like +when you heat some boundary oh it + + align:start position:0% +when you heat some boundary oh it + + + align:start position:0% +when you heat some boundary oh it +doesn't really help you to reduce the + + align:start position:0% +doesn't really help you to reduce the + + + align:start position:0% +doesn't really help you to reduce the +amplitude okay so the correct answer is + + align:start position:0% +amplitude okay so the correct answer is + + + align:start position:0% +amplitude okay so the correct answer is +you would choose your give the device + + align:start position:0% +you would choose your give the device + + + align:start position:0% +you would choose your give the device +that you will do it critically damped + + align:start position:0% +that you will do it critically damped + + + align:start position:0% +that you will do it critically damped +okay so before we end the section today + + align:start position:0% +okay so before we end the section today + + + align:start position:0% +okay so before we end the section today +I would like to post a question to you + + align:start position:0% +I would like to post a question to you + + + align:start position:0% +I would like to post a question to you +the first the thing with which we have + + align:start position:0% +the first the thing with which we have + + + align:start position:0% +the first the thing with which we have +learned from simple harmonic motion is + + align:start position:0% +learned from simple harmonic motion is + + + align:start position:0% +learned from simple harmonic motion is +that the energy is conserved in the + + align:start position:0% +that the energy is conserved in the + + + align:start position:0% +that the energy is conserved in the +simple harmonic motion okay I have the + + align:start position:0% +simple harmonic motion okay I have the + + + align:start position:0% +simple harmonic motion okay I have the +FS the spring force proportional to + + align:start position:0% +FS the spring force proportional to + + + align:start position:0% +FS the spring force proportional to +minus K times X and that energy is + + align:start position:0% +minus K times X and that energy is + + + align:start position:0% +minus K times X and that energy is +conserved okay but if I add a drag force + + align:start position:0% +conserved okay but if I add a drag force + + + align:start position:0% +conserved okay but if I add a drag force +in the form of minus P times V energy is + + align:start position:0% +in the form of minus P times V energy is + + + align:start position:0% +in the form of minus P times V energy is +not conserved right okay + + align:start position:0% +not conserved right okay + + + align:start position:0% +not conserved right okay +see that he was to issue a sedating now + + align:start position:0% +see that he was to issue a sedating now + + + align:start position:0% +see that he was to issue a sedating now +it's now oscillating right this scene is + + align:start position:0% +it's now oscillating right this scene is + + + align:start position:0% +it's now oscillating right this scene is +stop absolutely okay why you start the + + align:start position:0% +stop absolutely okay why you start the + + + align:start position:0% +stop absolutely okay why you start the +case mathematically okay we know what is + + align:start position:0% +case mathematically okay we know what is + + + align:start position:0% +case mathematically okay we know what is +happening physically because in this + + align:start position:0% +happening physically because in this + + + align:start position:0% +happening physically because in this +physical system because okay this a + + align:start position:0% +physical system because okay this a + + + align:start position:0% +physical system because okay this a +Mexican Hat is trying to push the air + + align:start position:0% +Mexican Hat is trying to push the air + + + align:start position:0% +Mexican Hat is trying to push the air +away so what is going to happen is that + + align:start position:0% +away so what is going to happen is that + + + align:start position:0% +away so what is going to happen is that +it's transferring the energy from the + + align:start position:0% +it's transferring the energy from the + + + align:start position:0% +it's transferring the energy from the +system to the to alemannic use of air + + align:start position:0% +system to the to alemannic use of air + + + align:start position:0% +system to the to alemannic use of air +okay so it's a separating the air so the + + align:start position:0% +okay so it's a separating the air so the + + + align:start position:0% +okay so it's a separating the air so the +energy goes away but why the + + align:start position:0% +energy goes away but why the + + + align:start position:0% +energy goes away but why the +mathematical form looks so similar and + + align:start position:0% +mathematical form looks so similar and + + + align:start position:0% +mathematical form looks so similar and +it does different thing and think about + + align:start position:0% +it does different thing and think about + + + align:start position:0% +it does different thing and think about +it and I'm not going to talk talk about + + align:start position:0% +it and I'm not going to talk talk about + + + align:start position:0% +it and I'm not going to talk talk about +the answer today and thank you Matt + + align:start position:0% +the answer today and thank you Matt + + + align:start position:0% +the answer today and thank you Matt +thank you very much and we will continue + + align:start position:0% +thank you very much and we will continue + + + align:start position:0% +thank you very much and we will continue +next time to see what we can learn if I + + align:start position:0% +next time to see what we can learn if I + + + align:start position:0% +next time to see what we can learn if I +start to type the oscillation back \ No newline at end of file diff --git a/TgPcNnUrE24.txt b/TgPcNnUrE24.txt new file mode 100644 index 0000000000000000000000000000000000000000..6a281edf84adee147a93eec86dcff6668b13248f --- /dev/null +++ b/TgPcNnUrE24.txt @@ -0,0 +1,9307 @@ +align:start position:0% + +so we spend the last few lectures + + align:start position:0% +so we spend the last few lectures + + + align:start position:0% +so we spend the last few lectures +discussing similarities regularity lemma + + align:start position:0% +discussing similarities regularity lemma + + + align:start position:0% +discussing similarities regularity lemma +so we saw that this is an important tool + + align:start position:0% +so we saw that this is an important tool + + + align:start position:0% +so we saw that this is an important tool +with important applications allowing you + + align:start position:0% +with important applications allowing you + + + align:start position:0% +with important applications allowing you +to do things like a proof of roster via + + align:start position:0% +to do things like a proof of roster via + + + align:start position:0% +to do things like a proof of roster via +graph theory one of the concepts that + + align:start position:0% +graph theory one of the concepts that + + + align:start position:0% +graph theory one of the concepts that +came up when we were discussing this + + align:start position:0% +came up when we were discussing this + + + align:start position:0% +came up when we were discussing this +statement of summary destroy clarity + + align:start position:0% +statement of summary destroy clarity + + + align:start position:0% +statement of summary destroy clarity +lemma it's that of pseudo randomness so + + align:start position:0% +lemma it's that of pseudo randomness so + + + align:start position:0% +lemma it's that of pseudo randomness so +the statement of some Redis graph + + align:start position:0% +the statement of some Redis graph + + + align:start position:0% +the statement of some Redis graph +regularity lemma is that you can + + align:start position:0% +regularity lemma is that you can + + + align:start position:0% +regularity lemma is that you can +partition an arbitrary graph into a + + align:start position:0% +partition an arbitrary graph into a + + + align:start position:0% +partition an arbitrary graph into a +bounded number of pieces so that the + + align:start position:0% +bounded number of pieces so that the + + + align:start position:0% +bounded number of pieces so that the +graph looks random like as we call it + + align:start position:0% +graph looks random like as we call it + + + align:start position:0% +graph looks random like as we call it +between most pairs of parts okay so what + + align:start position:0% +between most pairs of parts okay so what + + + align:start position:0% +between most pairs of parts okay so what +does random like me so that's something + + align:start position:0% +does random like me so that's something + + + align:start position:0% +does random like me so that's something +that I want to discuss the next couple + + align:start position:0% +that I want to discuss the next couple + + + align:start position:0% +that I want to discuss the next couple +of lectures and this is the idea of + + align:start position:0% +of lectures and this is the idea of + + + align:start position:0% +of lectures and this is the idea of +pseudo randomness which is a it's a + + align:start position:0% +pseudo randomness which is a it's a + + + align:start position:0% +pseudo randomness which is a it's a +concept that it's really prevalent in + + align:start position:0% +concept that it's really prevalent in + + + align:start position:0% +concept that it's really prevalent in +combinatorics in the radical computer + + align:start position:0% +combinatorics in the radical computer + + + align:start position:0% +combinatorics in the radical computer +science and in many different areas and + + align:start position:0% +science and in many different areas and + + + align:start position:0% +science and in many different areas and +what pseudo randomness tries to capture + + align:start position:0% +what pseudo randomness tries to capture + + + align:start position:0% +what pseudo randomness tries to capture +is in what ways can a non random object + + align:start position:0% +is in what ways can a non random object + + + align:start position:0% +is in what ways can a non random object +look random + + align:start position:0% +look random + + + align:start position:0% +look random +alright so before diving into some + + align:start position:0% +alright so before diving into some + + + align:start position:0% +alright so before diving into some +specific mathematics I want to offer + + align:start position:0% +specific mathematics I want to offer + + + align:start position:0% +specific mathematics I want to offer +some philosophical remarks and so you + + align:start position:0% +some philosophical remarks and so you + + + align:start position:0% +some philosophical remarks and so you +might know that you know income on a + + align:start position:0% +might know that you know income on a + + + align:start position:0% +might know that you know income on a +computer you want to generate a random + + align:start position:0% +computer you want to generate a random + + + align:start position:0% +computer you want to generate a random +number while you type in a Rand and it + + align:start position:0% +number while you type in a Rand and it + + + align:start position:0% +number while you type in a Rand and it +gives you a random number but of course + + align:start position:0% +gives you a random number but of course + + + align:start position:0% +gives you a random number but of course +you know that it's not necessarily true + + align:start position:0% +you know that it's not necessarily true + + + align:start position:0% +you know that it's not necessarily true +randomness it came from some + + align:start position:0% +randomness it came from some + + + align:start position:0% +randomness it came from some +pseudo-random generator + + align:start position:0% +pseudo-random generator + + + align:start position:0% +pseudo-random generator +probably there's some seed and some + + align:start position:0% +probably there's some seed and some + + + align:start position:0% +probably there's some seed and some +complex looking function and output + + align:start position:0% +complex looking function and output + + + align:start position:0% +complex looking function and output +something that you couldn't distinguish + + align:start position:0% +something that you couldn't distinguish + + + align:start position:0% +something that you couldn't distinguish +from random but it might not actually be + + align:start position:0% +from random but it might not actually be + + + align:start position:0% +from random but it might not actually be +random it's just something that looks in + + align:start position:0% +random it's just something that looks in + + + align:start position:0% +random it's just something that looks in +many different ways like random so there + + align:start position:0% +many different ways like random so there + + + align:start position:0% +many different ways like random so there +is this concept of randomness you can + + align:start position:0% +is this concept of randomness you can + + + align:start position:0% +is this concept of randomness you can +think about a random graph right + + align:start position:0% +think about a random graph right + + + align:start position:0% +think about a random graph right +generate this address writing a random + + align:start position:0% +generate this address writing a random + + + align:start position:0% +generate this address writing a random +graph every edge occurs independently + + align:start position:0% +graph every edge occurs independently + + + align:start position:0% +graph every edge occurs independently +with some probability but I can also + + align:start position:0% +with some probability but I can also + + + align:start position:0% +with some probability but I can also +show you some graph some specific graph + + align:start position:0% +show you some graph some specific graph + + + align:start position:0% +show you some graph some specific graph +which I say well it's + + align:start position:0% +which I say well it's + + + align:start position:0% +which I say well it's +just for all intents and purposes just + + align:start position:0% +just for all intents and purposes just + + + align:start position:0% +just for all intents and purposes just +as good as a random graph so in what + + align:start position:0% +as good as a random graph so in what + + + align:start position:0% +as good as a random graph so in what +ways can we capture that concept so + + align:start position:0% +ways can we capture that concept so + + + align:start position:0% +ways can we capture that concept so +that's what I want to discuss and that's + + align:start position:0% +that's what I want to discuss and that's + + + align:start position:0% +that's what I want to discuss and that's +the topic of pseudo randomness and of + + align:start position:0% +the topic of pseudo randomness and of + + + align:start position:0% +the topic of pseudo randomness and of +course well you know this idea extends + + align:start position:0% +course well you know this idea extends + + + align:start position:0% +course well you know this idea extends +to in the many areas number theory and + + align:start position:0% +to in the many areas number theory and + + + align:start position:0% +to in the many areas number theory and +whatnot but we'll stick with graph + + align:start position:0% +whatnot but we'll stick with graph + + + align:start position:0% +whatnot but we'll stick with graph +theory in particular I want to explore + + align:start position:0% +theory in particular I want to explore + + + align:start position:0% +theory in particular I want to explore +today just one specific notion of pseudo + + align:start position:0% +today just one specific notion of pseudo + + + align:start position:0% +today just one specific notion of pseudo +randomness and this is comes from an + + align:start position:0% +randomness and this is comes from an + + + align:start position:0% +randomness and this is comes from an +important paper called quasi random + + align:start position:0% +important paper called quasi random + + + align:start position:0% +important paper called quasi random +graphs and this concept is due to Chung + + align:start position:0% +graphs and this concept is due to Chung + + + align:start position:0% +graphs and this concept is due to Chung +Graham and Wilson back in the late 80s + + align:start position:0% + + + + align:start position:0% + +so they defined various notions of + + align:start position:0% +so they defined various notions of + + + align:start position:0% +so they defined various notions of +pseudo randomness and I want to state + + align:start position:0% +pseudo randomness and I want to state + + + align:start position:0% +pseudo randomness and I want to state +them and what it turns out and the + + align:start position:0% +them and what it turns out and the + + + align:start position:0% +them and what it turns out and the +surprising part is that these notions + + align:start position:0% +surprising part is that these notions + + + align:start position:0% +surprising part is that these notions +these definitions although they look + + align:start position:0% +these definitions although they look + + + align:start position:0% +these definitions although they look +superficially different they're actually + + align:start position:0% +superficially different they're actually + + + align:start position:0% +superficially different they're actually +only equivalent to each other so let's + + align:start position:0% +only equivalent to each other so let's + + + align:start position:0% +only equivalent to each other so let's +see what the theorem says so the set up + + align:start position:0% +see what the theorem says so the set up + + + align:start position:0% +see what the theorem says so the set up +of this theorem is that you have some + + align:start position:0% +of this theorem is that you have some + + + align:start position:0% +of this theorem is that you have some +fixed real P between 0 & 1 + + align:start position:0% +fixed real P between 0 & 1 + + + align:start position:0% +fixed real P between 0 & 1 +and this is going to be your graph edge + + align:start position:0% +and this is going to be your graph edge + + + align:start position:0% +and this is going to be your graph edge +density so for any sequence of graphs GN + + align:start position:0% +density so for any sequence of graphs GN + + + align:start position:0% +density so for any sequence of graphs GN +so with so from now I'm going to drop + + align:start position:0% +so with so from now I'm going to drop + + + align:start position:0% +so with so from now I'm going to drop +the subscript G so subscript n so G will + + align:start position:0% +the subscript G so subscript n so G will + + + align:start position:0% +the subscript G so subscript n so G will +just be G n such that the number of + + align:start position:0% +just be G n such that the number of + + + align:start position:0% +just be G n such that the number of +vertices so to genius and vertex with + + align:start position:0% +vertices so to genius and vertex with + + + align:start position:0% +vertices so to genius and vertex with +extensity basically peep okay so this is + + align:start position:0% +extensity basically peep okay so this is + + + align:start position:0% +extensity basically peep okay so this is +your sequence of graphs and the claim is + + align:start position:0% +your sequence of graphs and the claim is + + + align:start position:0% +your sequence of graphs and the claim is +that we're going to state some set of + + align:start position:0% +that we're going to state some set of + + + align:start position:0% +that we're going to state some set of +properties and these properties are all + + align:start position:0% +properties and these properties are all + + + align:start position:0% +properties and these properties are all +going to be equivalent to each other + + align:start position:0% +going to be equivalent to each other + + + align:start position:0% +going to be equivalent to each other +[Applause] + + align:start position:0% + + + + align:start position:0% + +okay so all of these properties capture + + align:start position:0% +okay so all of these properties capture + + + align:start position:0% +okay so all of these properties capture +some notion of pseudo randomness in what + + align:start position:0% +some notion of pseudo randomness in what + + + align:start position:0% +some notion of pseudo randomness in what +ways does this graph G or really a + + align:start position:0% +ways does this graph G or really a + + + align:start position:0% +ways does this graph G or really a +sequence of graphs or you can talk about + + align:start position:0% +sequence of graphs or you can talk about + + + align:start position:0% +sequence of graphs or you can talk about +a specific graph and have some error + + align:start position:0% +a specific graph and have some error + + + align:start position:0% +a specific graph and have some error +parameters and error balance they're all + + align:start position:0% +parameters and error balance they're all + + + align:start position:0% +parameters and error balance they're all +roughly the same ideas so in what ways + + align:start position:0% +roughly the same ideas so in what ways + + + align:start position:0% +roughly the same ideas so in what ways +can we talk about this graph G being + + align:start position:0% +can we talk about this graph G being + + + align:start position:0% +can we talk about this graph G being +random like well we already saw one + + align:start position:0% +random like well we already saw one + + + align:start position:0% +random like well we already saw one +notion when we discussed similarities + + align:start position:0% +notion when we discussed similarities + + + align:start position:0% +notion when we discussed similarities +regularity lemma and let's see that here + + align:start position:0% +regularity lemma and let's see that here + + + align:start position:0% +regularity lemma and let's see that here +so this notion is known as discrepancy + + align:start position:0% +so this notion is known as discrepancy + + + align:start position:0% +so this notion is known as discrepancy +and it says that if I restrict my graph + + align:start position:0% +and it says that if I restrict my graph + + + align:start position:0% +and it says that if I restrict my graph +to looking only at edges between some + + align:start position:0% +to looking only at edges between some + + + align:start position:0% +to looking only at edges between some +pair of vertex sets then the number of + + align:start position:0% +pair of vertex sets then the number of + + + align:start position:0% +pair of vertex sets then the number of +edges should be roughly what you expect + + align:start position:0% +edges should be roughly what you expect + + + align:start position:0% +edges should be roughly what you expect +based on density along so this is + + align:start position:0% +based on density along so this is + + + align:start position:0% +based on density along so this is +basically the notion that came up in + + align:start position:0% +basically the notion that came up in + + + align:start position:0% +basically the notion that came up in +epsilon regularity this is essentially + + align:start position:0% +epsilon regularity this is essentially + + + align:start position:0% +epsilon regularity this is essentially +the same as saying that G is epsilon + + align:start position:0% +the same as saying that G is epsilon + + + align:start position:0% +the same as saying that G is epsilon +regular with itself for this epsilon now + + align:start position:0% +regular with itself for this epsilon now + + + align:start position:0% +regular with itself for this epsilon now +hidden in this little old parameter so + + align:start position:0% +hidden in this little old parameter so + + + align:start position:0% +hidden in this little old parameter so +that's one notion of pseudo randomness + + align:start position:0% +that's one notion of pseudo randomness + + + align:start position:0% +that's one notion of pseudo randomness +okay so here's another notion which is + + align:start position:0% +okay so here's another notion which is + + + align:start position:0% +okay so here's another notion which is +very similar so it's almost just a + + align:start position:0% +very similar so it's almost just a + + + align:start position:0% +very similar so it's almost just a +semantic difference okay so I have to do + + align:start position:0% +semantic difference okay so I have to do + + + align:start position:0% +semantic difference okay so I have to do +a little bit of work so let me call this + + align:start position:0% +a little bit of work so let me call this + + + align:start position:0% +a little bit of work so let me call this +this prime so it says that if you look + + align:start position:0% +this prime so it says that if you look + + + align:start position:0% +this prime so it says that if you look +at only edges within a set so instead of + + align:start position:0% +at only edges within a set so instead of + + + align:start position:0% +at only edges within a set so instead of +taking two sets I only look at one set + + align:start position:0% +taking two sets I only look at one set + + + align:start position:0% +taking two sets I only look at one set +and then look at how many edges are in + + align:start position:0% +and then look at how many edges are in + + + align:start position:0% +and then look at how many edges are in +there versus how many you should expect + + align:start position:0% +there versus how many you should expect + + + align:start position:0% +there versus how many you should expect +based on density alone + + align:start position:0% +based on density alone + + + align:start position:0% +based on density alone +these two numbers are also very similar + + align:start position:0% +these two numbers are also very similar + + + align:start position:0% +these two numbers are also very similar +to each other so let's get to something + + align:start position:0% +to each other so let's get to something + + + align:start position:0% +to each other so let's get to something +that looks dramatically different the + + align:start position:0% +that looks dramatically different the + + + align:start position:0% +that looks dramatically different the +next one I'm going to call count so + + align:start position:0% +next one I'm going to call count so + + + align:start position:0% +next one I'm going to call count so +count says that for every graph H the + + align:start position:0% +count says that for every graph H the + + + align:start position:0% +count says that for every graph H the +number of labeled copies of H in G okay + + align:start position:0% +number of labeled copies of H in G okay + + + align:start position:0% +number of labeled copies of H in G okay +so labeled copies I mean that the + + align:start position:0% +so labeled copies I mean that the + + + align:start position:0% +so labeled copies I mean that the +vertices of H are labeled so for every + + align:start position:0% +vertices of H are labeled so for every + + + align:start position:0% +vertices of H are labeled so for every +triangle there are six labeled triangles + + align:start position:0% +triangle there are six labeled triangles + + + align:start position:0% +triangle there are six labeled triangles +that correspond to that triangle in the + + align:start position:0% +that correspond to that triangle in the + + + align:start position:0% +that correspond to that triangle in the +graph the number of labeled copies of H + + align:start position:0% +graph the number of labeled copies of H + + + align:start position:0% +graph the number of labeled copies of H +is okay so what should you expect if + + align:start position:0% +is okay so what should you expect if + + + align:start position:0% +is okay so what should you expect if +this graph will truly random you expect + + align:start position:0% +this graph will truly random you expect + + + align:start position:0% +this graph will truly random you expect +P raised to the number of edges of h + + align:start position:0% +P raised to the number of edges of h + + + align:start position:0% +P raised to the number of edges of h +plus small error times n number raised + + align:start position:0% +plus small error times n number raised + + + align:start position:0% +plus small error times n number raised +to the number of vertices of H and just + + align:start position:0% +to the number of vertices of H and just + + + align:start position:0% +to the number of vertices of H and just +as a remark this little old term one + + align:start position:0% +as a remark this little old term one + + + align:start position:0% +as a remark this little old term one +term may depend on H so this condition + + align:start position:0% +term may depend on H so this condition + + + align:start position:0% +term may depend on H so this condition +count says for every graph H this is + + align:start position:0% +count says for every graph H this is + + + align:start position:0% +count says for every graph H this is +true and by that I mean for every H + + align:start position:0% +true and by that I mean for every H + + + align:start position:0% +true and by that I mean for every H +there's some sequence of decaying errors + + align:start position:0% +there's some sequence of decaying errors + + + align:start position:0% +there's some sequence of decaying errors +but that sequence of the K nares may + + align:start position:0% +but that sequence of the K nares may + + + align:start position:0% +but that sequence of the K nares may +depend on your graph H + + align:start position:0% + + + + align:start position:0% + +the next one is almost a special case of + + align:start position:0% +the next one is almost a special case of + + + align:start position:0% +the next one is almost a special case of +count + + align:start position:0% +count + + + align:start position:0% +count +it's called c4 and it says that the + + align:start position:0% +it's called c4 and it says that the + + + align:start position:0% +it's called c4 and it says that the +number of labelled copies of c-4 to the + + align:start position:0% +number of labelled copies of c-4 to the + + + align:start position:0% +number of labelled copies of c-4 to the +four cycle yes at most P raised to power + + align:start position:0% +four cycle yes at most P raised to power + + + align:start position:0% +four cycle yes at most P raised to power +4 ok so again what you should expect in + + align:start position:0% +4 ok so again what you should expect in + + + align:start position:0% +4 ok so again what you should expect in +a random setting just for cycle count + + align:start position:0% +a random setting just for cycle count + + + align:start position:0% +a random setting just for cycle count +alone I see already some of you are + + align:start position:0% +alone I see already some of you are + + + align:start position:0% +alone I see already some of you are +surprised and we'll discuss that you + + align:start position:0% +surprised and we'll discuss that you + + + align:start position:0% +surprised and we'll discuss that you +know this is an important constraint it + + align:start position:0% +know this is an important constraint it + + + align:start position:0% +know this is an important constraint it +turns out that alone implies everything + + align:start position:0% +turns out that alone implies everything + + + align:start position:0% +turns out that alone implies everything +just having the correct c4 count the + + align:start position:0% +just having the correct c4 count the + + + align:start position:0% +just having the correct c4 count the +next one we'll call Co degree and the co + + align:start position:0% +next one we'll call Co degree and the co + + + align:start position:0% +next one we'll call Co degree and the co +degree condition says that if you look + + align:start position:0% +degree condition says that if you look + + + align:start position:0% +degree condition says that if you look +at a pair of vertices and look at their + + align:start position:0% +at a pair of vertices and look at their + + + align:start position:0% +at a pair of vertices and look at their +number of common neighbors in other + + align:start position:0% +number of common neighbors in other + + + align:start position:0% +number of common neighbors in other +words their Co degree then what should + + align:start position:0% +words their Co degree then what should + + + align:start position:0% +words their Co degree then what should +you expect this quantity to be and + + align:start position:0% +you expect this quantity to be and + + + align:start position:0% +you expect this quantity to be and +vertices that possibly could be common + + align:start position:0% +vertices that possibly could be common + + + align:start position:0% +vertices that possibly could be common +neighbors and each one of them if this + + align:start position:0% +neighbors and each one of them if this + + + align:start position:0% +neighbors and each one of them if this +were a random graph with edge + + align:start position:0% +were a random graph with edge + + + align:start position:0% +were a random graph with edge +probability P then you expect the number + + align:start position:0% +probability P then you expect the number + + + align:start position:0% +probability P then you expect the number +of common neighbors to be around pqube a + + align:start position:0% +of common neighbors to be around pqube a + + + align:start position:0% +of common neighbors to be around pqube a +p squared n so the co degree condition + + align:start position:0% +p squared n so the co degree condition + + + align:start position:0% +p squared n so the co degree condition +is that this sum is small so most pairs + + align:start position:0% +is that this sum is small so most pairs + + + align:start position:0% +is that this sum is small so most pairs +of vertices have roughly the correct + + align:start position:0% +of vertices have roughly the correct + + + align:start position:0% +of vertices have roughly the correct +number of common neighbors degree yes + + align:start position:0% +number of common neighbors degree yes + + + align:start position:0% +number of common neighbors degree yes +number of common neighbors + + align:start position:0% + + + + align:start position:0% + +next in the last one certainly not the + + align:start position:0% +next in the last one certainly not the + + + align:start position:0% +next in the last one certainly not the +least is I can value condition so here + + align:start position:0% +least is I can value condition so here + + + align:start position:0% +least is I can value condition so here +we are going to denote by lambda 1 + + align:start position:0% +we are going to denote by lambda 1 + + + align:start position:0% +we are going to denote by lambda 1 +through lambda G the eigenvalues of the + + align:start position:0% +through lambda G the eigenvalues of the + + + align:start position:0% +through lambda G the eigenvalues of the +adjacency matrix of G okay so we saw + + align:start position:0% +adjacency matrix of G okay so we saw + + + align:start position:0% +adjacency matrix of G okay so we saw +this object in the last lecture I + + align:start position:0% +this object in the last lecture I + + + align:start position:0% +this object in the last lecture I +include multiplicities if some + + align:start position:0% +include multiplicities if some + + + align:start position:0% +include multiplicities if some +eigenvalue occurs with multiple times + + align:start position:0% +eigenvalue occurs with multiple times + + + align:start position:0% +eigenvalue occurs with multiple times +that included multiple times so the + + align:start position:0% +that included multiple times so the + + + align:start position:0% +that included multiple times so the +eigenvalue condition says that the top + + align:start position:0% +eigenvalue condition says that the top + + + align:start position:0% +eigenvalue condition says that the top +eigenvalue is around pn and that more + + align:start position:0% +eigenvalue is around pn and that more + + + align:start position:0% +eigenvalue is around pn and that more +importantly the other eigenvalues are + + align:start position:0% +importantly the other eigenvalues are + + + align:start position:0% +importantly the other eigenvalues are +all quite small now for D regular graph + + align:start position:0% +all quite small now for D regular graph + + + align:start position:0% +all quite small now for D regular graph +the top I can value it's fine to think + + align:start position:0% +the top I can value it's fine to think + + + align:start position:0% +the top I can value it's fine to think +about D regular graphs you know if you + + align:start position:0% +about D regular graphs you know if you + + + align:start position:0% +about D regular graphs you know if you +want to get some intuition out of this + + align:start position:0% +want to get some intuition out of this + + + align:start position:0% +want to get some intuition out of this +term for D regular graph the top I can + + align:start position:0% +term for D regular graph the top I can + + + align:start position:0% +term for D regular graph the top I can +value is equal to D because the top + + align:start position:0% +value is equal to D because the top + + + align:start position:0% +value is equal to D because the top +eigenvector is there's the old one + + align:start position:0% +eigenvector is there's the old one + + + align:start position:0% +eigenvector is there's the old one +vector so top eigenvector is a one + + align:start position:0% +vector so top eigenvector is a one + + + align:start position:0% +vector so top eigenvector is a one +vector which has eigen value T and what + + align:start position:0% +vector which has eigen value T and what + + + align:start position:0% +vector which has eigen value T and what +I can value condition says is that all + + align:start position:0% +I can value condition says is that all + + + align:start position:0% +I can value condition says is that all +the other eigen values are + + align:start position:0% + + + + align:start position:0% + +much smaller right so here I'm thinking + + align:start position:0% +much smaller right so here I'm thinking + + + align:start position:0% +much smaller right so here I'm thinking +of des on the same order of SN okay so + + align:start position:0% +of des on the same order of SN okay so + + + align:start position:0% +of des on the same order of SN okay so +this is the theorem so that's what we'll + + align:start position:0% +this is the theorem so that's what we'll + + + align:start position:0% +this is the theorem so that's what we'll +do today well prove that all of these + + align:start position:0% +do today well prove that all of these + + + align:start position:0% +do today well prove that all of these +properties are equivalent to each other + + align:start position:0% +properties are equivalent to each other + + + align:start position:0% +properties are equivalent to each other +and all of these properties you should + + align:start position:0% +and all of these properties you should + + + align:start position:0% +and all of these properties you should +think of as characterizations of pseudo + + align:start position:0% +think of as characterizations of pseudo + + + align:start position:0% +think of as characterizations of pseudo +randomness and of course this theorem + + align:start position:0% +randomness and of course this theorem + + + align:start position:0% +randomness and of course this theorem +guarantees us that it doesn't matter + + align:start position:0% +guarantees us that it doesn't matter + + + align:start position:0% +guarantees us that it doesn't matter +which one you use their own equivalent + + align:start position:0% +which one you use their own equivalent + + + align:start position:0% +which one you use their own equivalent +to each other and you know our proofs + + align:start position:0% +to each other and you know our proofs + + + align:start position:0% +to each other and you know our proofs +are actually going to be I mean I'm + + align:start position:0% +are actually going to be I mean I'm + + + align:start position:0% +are actually going to be I mean I'm +going to try to do everything fairly + + align:start position:0% +going to try to do everything fairly + + + align:start position:0% +going to try to do everything fairly +slowly but none of these proofs are + + align:start position:0% +slowly but none of these proofs are + + + align:start position:0% +slowly but none of these proofs are +difficult we're not going to use any + + align:start position:0% +difficult we're not going to use any + + + align:start position:0% +difficult we're not going to use any +fancy tools like some radix regularity + + align:start position:0% +fancy tools like some radix regularity + + + align:start position:0% +fancy tools like some radix regularity +lemma and in particular all of these + + align:start position:0% +lemma and in particular all of these + + + align:start position:0% +lemma and in particular all of these +quantitative errors are reasonably + + align:start position:0% +quantitative errors are reasonably + + + align:start position:0% +quantitative errors are reasonably +dependent on each other so I've stated + + align:start position:0% +dependent on each other so I've stated + + + align:start position:0% +dependent on each other so I've stated +this theorem so far in this form where + + align:start position:0% +this theorem so far in this form where + + + align:start position:0% +this theorem so far in this form where +there's a little one error but + + align:start position:0% +there's a little one error but + + + align:start position:0% +there's a little one error but +equivalent ly so can equivalently state + + align:start position:0% +equivalent ly so can equivalently state + + + align:start position:0% +equivalent ly so can equivalently state +them State theorem for example disk with + + align:start position:0% +them State theorem for example disk with + + + align:start position:0% +them State theorem for example disk with +an epsilon error which is that some + + align:start position:0% +an epsilon error which is that some + + + align:start position:0% +an epsilon error which is that some +inequality is true with a most epsilon + + align:start position:0% +inequality is true with a most epsilon + + + align:start position:0% +inequality is true with a most epsilon +error instead of oh and you have a + + align:start position:0% +error instead of oh and you have a + + + align:start position:0% +error instead of oh and you have a +different epsilon for each one of them + + align:start position:0% +different epsilon for each one of them + + + align:start position:0% +different epsilon for each one of them +and the theorem turns out that okay so + + align:start position:0% +and the theorem turns out that okay so + + + align:start position:0% +and the theorem turns out that okay so +the proof of this theorem will be that + + align:start position:0% +the proof of this theorem will be that + + + align:start position:0% +the proof of this theorem will be that +these conditions are true so all + + align:start position:0% +these conditions are true so all + + + align:start position:0% +these conditions are true so all +equivalent up to at most a polynomial + + align:start position:0% +equivalent up to at most a polynomial + + + align:start position:0% +equivalent up to at most a polynomial +change in the epsilon in other words so + + align:start position:0% +change in the epsilon in other words so + + + align:start position:0% +change in the epsilon in other words so +property one is true for epsilon implies + + align:start position:0% +property one is true for epsilon implies + + + align:start position:0% +property one is true for epsilon implies +that property two is true for some + + align:start position:0% +that property two is true for some + + + align:start position:0% +that property two is true for some +epsilon raised to a constant so the + + align:start position:0% +epsilon raised to a constant so the + + + align:start position:0% +epsilon raised to a constant so the +changes in parameters are quite + + align:start position:0% +changes in parameters are quite + + + align:start position:0% +changes in parameters are quite +reasonable and we'll see this from the + + align:start position:0% +reasonable and we'll see this from the + + + align:start position:0% +reasonable and we'll see this from the +proof but I won't say it again + + align:start position:0% +proof but I won't say it again + + + align:start position:0% +proof but I won't say it again +explicitly any + + align:start position:0% +explicitly any + + + align:start position:0% +explicitly any +questions so far about the statement of + + align:start position:0% +questions so far about the statement of + + + align:start position:0% +questions so far about the statement of +this theorem so as I mentioned just now + + align:start position:0% +this theorem so as I mentioned just now + + + align:start position:0% +this theorem so as I mentioned just now +the most surprising part of this theorem + + align:start position:0% +the most surprising part of this theorem + + + align:start position:0% +the most surprising part of this theorem +and the one that I want you to pay the + + align:start position:0% +and the one that I want you to pay the + + + align:start position:0% +and the one that I want you to pay the +most attention to is the c4 condition + + align:start position:0% +most attention to is the c4 condition + + + align:start position:0% +most attention to is the c4 condition +this seems at least at face value the + + align:start position:0% +this seems at least at face value the + + + align:start position:0% +this seems at least at face value the +weakest condition among all of them it + + align:start position:0% +weakest condition among all of them it + + + align:start position:0% +weakest condition among all of them it +just says the correct c4 count but it + + align:start position:0% +just says the correct c4 count but it + + + align:start position:0% +just says the correct c4 count but it +turns out to be equivalent to everything + + align:start position:0% +turns out to be equivalent to everything + + + align:start position:0% +turns out to be equivalent to everything +else and there's something special about + + align:start position:0% +else and there's something special about + + + align:start position:0% +else and there's something special about +c-4 right if I replace c-4 by c3 by just + + align:start position:0% +c-4 right if I replace c-4 by c3 by just + + + align:start position:0% +c-4 right if I replace c-4 by c3 by just +triangles then that's not true so I want + + align:start position:0% +triangles then that's not true so I want + + + align:start position:0% +triangles then that's not true so I want +you to think about you know where the + + align:start position:0% +you to think about you know where the + + + align:start position:0% +you to think about you know where the +c-4 played this important role how does + + align:start position:0% +c-4 played this important role how does + + + align:start position:0% +c-4 played this important role how does +it play this important role okay so + + align:start position:0% +it play this important role okay so + + + align:start position:0% +it play this important role okay so +let's get started with the proof but + + align:start position:0% +let's get started with the proof but + + + align:start position:0% +let's get started with the proof but +before that let me so in this proof one + + align:start position:0% +before that let me so in this proof one + + + align:start position:0% +before that let me so in this proof one +recurring theme is that we're going to + + align:start position:0% +recurring theme is that we're going to + + + align:start position:0% +recurring theme is that we're going to +be using the Cauchy Schwarz inequality + + align:start position:0% +be using the Cauchy Schwarz inequality + + + align:start position:0% +be using the Cauchy Schwarz inequality +many times and I want to just begin with + + align:start position:0% +many times and I want to just begin with + + + align:start position:0% +many times and I want to just begin with +an exercise that gets you some + + align:start position:0% +an exercise that gets you some + + + align:start position:0% +an exercise that gets you some +familiarity with applying the Cauchy + + align:start position:0% +familiarity with applying the Cauchy + + + align:start position:0% +familiarity with applying the Cauchy +Schwarz inequality and this simple tool + + align:start position:0% +Schwarz inequality and this simple tool + + + align:start position:0% +Schwarz inequality and this simple tool +but it's extremely powerful and + + align:start position:0% +but it's extremely powerful and + + + align:start position:0% +but it's extremely powerful and +worthwhile to you know master how to use + + align:start position:0% +worthwhile to you know master how to use + + + align:start position:0% +worthwhile to you know master how to use +the Cauchy Schwarz inequality okay so + + align:start position:0% +the Cauchy Schwarz inequality okay so + + + align:start position:0% +the Cauchy Schwarz inequality okay so +let's let's get some practice let me + + align:start position:0% +let's let's get some practice let me + + + align:start position:0% +let's let's get some practice let me +prove a claim which is not directly + + align:start position:0% +prove a claim which is not directly + + + align:start position:0% +prove a claim which is not directly +related to the proof of the theorem but + + align:start position:0% +related to the proof of the theorem but + + + align:start position:0% +related to the proof of the theorem but +it's indirectly in that explains + + align:start position:0% +it's indirectly in that explains + + + align:start position:0% +it's indirectly in that explains +somewhat the c-4 condition why we have + + align:start position:0% +somewhat the c-4 condition why we have + + + align:start position:0% +somewhat the c-4 condition why we have +less than or equal to over there okay so + + align:start position:0% +less than or equal to over there okay so + + + align:start position:0% +less than or equal to over there okay so +the lemma is that if you have a graph on + + align:start position:0% +the lemma is that if you have a graph on + + + align:start position:0% +the lemma is that if you have a graph on +n vertices such that the number of edges + + align:start position:0% +n vertices such that the number of edges + + + align:start position:0% +n vertices such that the number of edges +is at least P and squared over 2 so edge + + align:start position:0% +is at least P and squared over 2 so edge + + + align:start position:0% +is at least P and squared over 2 so edge +density basically P then the number of + + align:start position:0% +density basically P then the number of + + + align:start position:0% +density basically P then the number of +labeled copies of c-4 is at least + + align:start position:0% + + + + align:start position:0% + +e to the 4 - little one and so if you + + align:start position:0% +e to the 4 - little one and so if you + + + align:start position:0% +e to the 4 - little one and so if you +have a graph with edge density P P is a + + align:start position:0% +have a graph with edge density P P is a + + + align:start position:0% +have a graph with edge density P P is a +constant then the number of C forces are + + align:start position:0% +constant then the number of C forces are + + + align:start position:0% +constant then the number of C forces are +at least roughly what you would expect + + align:start position:0% +at least roughly what you would expect + + + align:start position:0% +at least roughly what you would expect +in a random graph alright so let's see + + align:start position:0% +in a random graph alright so let's see + + + align:start position:0% +in a random graph alright so let's see +how to do this and I want to show this + + align:start position:0% +how to do this and I want to show this + + + align:start position:0% +how to do this and I want to show this +inequality as a me I'll show you how to + + align:start position:0% +inequality as a me I'll show you how to + + + align:start position:0% +inequality as a me I'll show you how to +prove this inequality but I also want to + + align:start position:0% +prove this inequality but I also want to + + + align:start position:0% +prove this inequality but I also want to +draw sequence of pictures that at least + + align:start position:0% +draw sequence of pictures that at least + + + align:start position:0% +draw sequence of pictures that at least +to explain how I think about + + align:start position:0% +to explain how I think about + + + align:start position:0% +to explain how I think about +applications of the Cauchy Schwarz + + align:start position:0% +applications of the Cauchy Schwarz + + + align:start position:0% +applications of the Cauchy Schwarz +inequality ok so the first thing is that + + align:start position:0% +inequality ok so the first thing is that + + + align:start position:0% +inequality ok so the first thing is that +we are counting labelled copies of c4 + + align:start position:0% +we are counting labelled copies of c4 + + + align:start position:0% +we are counting labelled copies of c4 +and this is basically but not exactly + + align:start position:0% +and this is basically but not exactly + + + align:start position:0% +and this is basically but not exactly +the same as number of homomorphic copies + + align:start position:0% +the same as number of homomorphic copies + + + align:start position:0% +the same as number of homomorphic copies +of c-4 in g so by this guy here i really + + align:start position:0% +of c-4 in g so by this guy here i really + + + align:start position:0% +of c-4 in g so by this guy here i really +just mean you are mapping vertices of + + align:start position:0% +just mean you are mapping vertices of + + + align:start position:0% +just mean you are mapping vertices of +c-4 to g so that the edges all map to + + align:start position:0% +c-4 to g so that the edges all map to + + + align:start position:0% +c-4 to g so that the edges all map to +edges but we are allowing not + + align:start position:0% +edges but we are allowing not + + + align:start position:0% +edges but we are allowing not +necessarily injective maps c4 to 2g but + + align:start position:0% +necessarily injective maps c4 to 2g but + + + align:start position:0% +necessarily injective maps c4 to 2g but +that's okay so the number of non + + align:start position:0% +that's okay so the number of non + + + align:start position:0% +that's okay so the number of non +injective maps yes most cubic so we're + + align:start position:0% +injective maps yes most cubic so we're + + + align:start position:0% +injective maps yes most cubic so we're +not really affecting our account so it's + + align:start position:0% +not really affecting our account so it's + + + align:start position:0% +not really affecting our account so it's +enough to think about homomorphic copies + + align:start position:0% + + + + align:start position:0% + +okay so what's going on here + + align:start position:0% +okay so what's going on here + + + align:start position:0% +okay so what's going on here +so let me draw a sequence of pictures + + align:start position:0% +so let me draw a sequence of pictures + + + align:start position:0% +so let me draw a sequence of pictures +illustrating this calculation so first + + align:start position:0% +illustrating this calculation so first + + + align:start position:0% +illustrating this calculation so first +we are thinking about counting c4 c4 I + + align:start position:0% + + + + align:start position:0% + +can rewrite the c-4 count as a sum over + + align:start position:0% +can rewrite the c-4 count as a sum over + + + align:start position:0% +can rewrite the c-4 count as a sum over +pairs of vertices of G as the squared Co + + align:start position:0% +pairs of vertices of G as the squared Co + + + align:start position:0% +pairs of vertices of G as the squared Co +degree and what happens here so this is + + align:start position:0% +degree and what happens here so this is + + + align:start position:0% +degree and what happens here so this is +true mean it's not hard to see why this + + align:start position:0% +true mean it's not hard to see why this + + + align:start position:0% +true mean it's not hard to see why this +is true but I want to draw this in + + align:start position:0% +is true but I want to draw this in + + + align:start position:0% +is true but I want to draw this in +pictures because you know we have larger + + align:start position:0% +pictures because you know we have larger + + + align:start position:0% +pictures because you know we have larger +and bigger graphs may be more difficult + + align:start position:0% +and bigger graphs may be more difficult + + + align:start position:0% +and bigger graphs may be more difficult +to think about the algebra unless you + + align:start position:0% +to think about the algebra unless you + + + align:start position:0% +to think about the algebra unless you +have some visualization so what happens + + align:start position:0% +have some visualization so what happens + + + align:start position:0% +have some visualization so what happens +here is that I noticed that this c4 has + + align:start position:0% +here is that I noticed that this c4 has + + + align:start position:0% +here is that I noticed that this c4 has +a certain reflection namely it has a + + align:start position:0% +a certain reflection namely it has a + + + align:start position:0% +a certain reflection namely it has a +reflection along this horizontal line + + align:start position:0% +reflection along this horizontal line + + + align:start position:0% +reflection along this horizontal line +and so if I put these two vertices as U + + align:start position:0% +and so if I put these two vertices as U + + + align:start position:0% +and so if I put these two vertices as U +and D then this reflection tells you + + align:start position:0% +and D then this reflection tells you + + + align:start position:0% +and D then this reflection tells you +that you can write this homomorphic + + align:start position:0% +that you can write this homomorphic + + + align:start position:0% +that you can write this homomorphic +number who more copies as the sum of + + align:start position:0% +number who more copies as the sum of + + + align:start position:0% +number who more copies as the sum of +squares but once you have this + + align:start position:0% +squares but once you have this + + + align:start position:0% +squares but once you have this +reflection and reflections are super + + align:start position:0% +reflection and reflections are super + + + align:start position:0% +reflection and reflections are super +useful because they allow us to get + + align:start position:0% +useful because they allow us to get + + + align:start position:0% +useful because they allow us to get +something into a square and then right + + align:start position:0% +something into a square and then right + + + align:start position:0% +something into a square and then right +after apply the Cauchy Schwarz + + align:start position:0% +after apply the Cauchy Schwarz + + + align:start position:0% +after apply the Cauchy Schwarz +inequality so we apply Cauchy Schwarz + + align:start position:0% +inequality so we apply Cauchy Schwarz + + + align:start position:0% +inequality so we apply Cauchy Schwarz +here and we obtain that this sum is at + + align:start position:0% +here and we obtain that this sum is at + + + align:start position:0% +here and we obtain that this sum is at +most where I can pull the square out and + + align:start position:0% +most where I can pull the square out and + + + align:start position:0% +most where I can pull the square out and +I need to think about what is the + + align:start position:0% +I need to think about what is the + + + align:start position:0% +I need to think about what is the +correct factor to put out here and that + + align:start position:0% +correct factor to put out here and that + + + align:start position:0% +correct factor to put out here and that +should be okay so what's the correct + + align:start position:0% +should be okay so what's the correct + + + align:start position:0% +should be okay so what's the correct +factor that I should put out there okay + + align:start position:0% +factor that I should put out there okay + + + align:start position:0% +factor that I should put out there okay +so 1 over N squared so I don't actually + + align:start position:0% +so 1 over N squared so I don't actually + + + align:start position:0% +so 1 over N squared so I don't actually +like doing this kind of calculations + + align:start position:0% +like doing this kind of calculations + + + align:start position:0% +like doing this kind of calculations +which sums because then you have to keep + + align:start position:0% +which sums because then you have to keep + + + align:start position:0% +which sums because then you have to keep +keep track of these normalizing factors + + align:start position:0% +keep track of these normalizing factors + + + align:start position:0% +keep track of these normalizing factors +one of the upcoming chapters when we + + align:start position:0% +one of the upcoming chapters when we + + + align:start position:0% +one of the upcoming chapters when we +discuss graph limits or in fact you can + + align:start position:0% +discuss graph limits or in fact you can + + + align:start position:0% +discuss graph limits or in fact you can +even do this instead of taking sums if + + align:start position:0% +even do this instead of taking sums if + + + align:start position:0% +even do this instead of taking sums if +you take an average if you take an + + align:start position:0% +you take an average if you take an + + + align:start position:0% +you take an average if you take an +expectation then it turns out you never + + align:start position:0% +expectation then it turns out you never + + + align:start position:0% +expectation then it turns out you never +have to worry about these normalizing + + align:start position:0% +have to worry about these normalizing + + + align:start position:0% +have to worry about these normalizing +factors and so on somehow normalizing + + align:start position:0% +factors and so on somehow normalizing + + + align:start position:0% +factors and so on somehow normalizing +factor should never bother you if you do + + align:start position:0% +factor should never bother you if you do + + + align:start position:0% +factor should never bother you if you do +it correctly but just to make sure + + align:start position:0% +it correctly but just to make sure + + + align:start position:0% +it correctly but just to make sure +things are correct + + align:start position:0% +things are correct + + + align:start position:0% +things are correct +this keep me in check all right so what + + align:start position:0% +this keep me in check all right so what + + + align:start position:0% +this keep me in check all right so what +happened in this step in this step we + + align:start position:0% +happened in this step in this step we + + + align:start position:0% +happened in this step in this step we +pulled out that square and pictorially + + align:start position:0% +pulled out that square and pictorially + + + align:start position:0% +pulled out that square and pictorially +what happens is that we got rid of half + + align:start position:0% +what happens is that we got rid of half + + + align:start position:0% +what happens is that we got rid of half +of this picture so we used + + align:start position:0% +of this picture so we used + + + align:start position:0% +of this picture so we used +cauchy-schwarz and we wiped out half of + + align:start position:0% +cauchy-schwarz and we wiped out half of + + + align:start position:0% +cauchy-schwarz and we wiped out half of +the picture and now what we can do is + + align:start position:0% +the picture and now what we can do is + + + align:start position:0% +the picture and now what we can do is +while we're counting these guys these + + align:start position:0% +while we're counting these guys these + + + align:start position:0% +while we're counting these guys these +paths of length two but I can + + align:start position:0% +paths of length two but I can + + + align:start position:0% +paths of length two but I can +reprioritize this picture so that it + + align:start position:0% +reprioritize this picture so that it + + + align:start position:0% +reprioritize this picture so that it +looks like that and now I notice that + + align:start position:0% +looks like that and now I notice that + + + align:start position:0% +looks like that and now I notice that +there is one more reflection all right + + align:start position:0% +there is one more reflection all right + + + align:start position:0% +there is one more reflection all right +so there's one more reflection and + + align:start position:0% +so there's one more reflection and + + + align:start position:0% +so there's one more reflection and +that's the reflection around the + + align:start position:0% +that's the reflection around the + + + align:start position:0% +that's the reflection around the +vertical axis so let me call this top + + align:start position:0% +vertical axis so let me call this top + + + align:start position:0% +vertical axis so let me call this top +vertex X and I can rewrite the sum okay + + align:start position:0% +vertex X and I can rewrite the sum okay + + + align:start position:0% +vertex X and I can rewrite the sum okay +so once more with your cauchy-schwarz + + align:start position:0% +so once more with your cauchy-schwarz + + + align:start position:0% +so once more with your cauchy-schwarz +which allows us to get rid of half of + + align:start position:0% +which allows us to get rid of half of + + + align:start position:0% +which allows us to get rid of half of +the picture and now I'm going to draw + + align:start position:0% +the picture and now I'm going to draw + + + align:start position:0% +the picture and now I'm going to draw +the picture first Stan you see that what + + align:start position:0% +the picture first Stan you see that what + + + align:start position:0% +the picture first Stan you see that what +we should be left with it's just a + + align:start position:0% +we should be left with it's just a + + + align:start position:0% +we should be left with it's just a +single edge and then you write down the + + align:start position:0% +single edge and then you write down the + + + align:start position:0% +single edge and then you write down the +correct sum making sure that all the + + align:start position:0% +correct sum making sure that all the + + + align:start position:0% +correct sum making sure that all the +parentheses and normalizations are + + align:start position:0% +parentheses and normalizations are + + + align:start position:0% +parentheses and normalizations are +correct but somehow that doesn't worry + + align:start position:0% +correct but somehow that doesn't worry + + + align:start position:0% +correct but somehow that doesn't worry +me so much because I know this what that + + align:start position:0% +me so much because I know this what that + + + align:start position:0% +me so much because I know this what that +means the + + align:start position:0% + + + + align:start position:0% + +but whatever it is were just summing the + + align:start position:0% +but whatever it is were just summing the + + + align:start position:0% +but whatever it is were just summing the +number of edges so that's just a number + + align:start position:0% +number of edges so that's just a number + + + align:start position:0% +number of edges so that's just a number +of edges and okay so we put everything + + align:start position:0% +of edges and okay so we put everything + + + align:start position:0% +of edges and okay so we put everything +in and we find that the final quantity + + align:start position:0% +in and we find that the final quantity + + + align:start position:0% +in and we find that the final quantity +is at least P raised to 4 and 2 4 ok so + + align:start position:0% +is at least P raised to 4 and 2 4 ok so + + + align:start position:0% +is at least P raised to 4 and 2 4 ok so +I did this quite slowly but and also + + align:start position:0% +I did this quite slowly but and also + + + align:start position:0% +I did this quite slowly but and also +emphasizing the sequence of pictures + + align:start position:0% +emphasizing the sequence of pictures + + + align:start position:0% +emphasizing the sequence of pictures +on and party to tell you like how I + + align:start position:0% +on and party to tell you like how I + + + align:start position:0% +on and party to tell you like how I +think about these inequalities because + + align:start position:0% +think about these inequalities because + + + align:start position:0% +think about these inequalities because +for other similar looking inequalities + + align:start position:0% +for other similar looking inequalities + + + align:start position:0% +for other similar looking inequalities +in fact there is something called + + align:start position:0% +in fact there is something called + + + align:start position:0% +in fact there is something called +sidorenko's conjecture which I may + + align:start position:0% +sidorenko's conjecture which I may + + + align:start position:0% +sidorenko's conjecture which I may +discuss more in a future lecture that + + align:start position:0% +discuss more in a future lecture that + + + align:start position:0% +discuss more in a future lecture that +says that this kind of inequality should + + align:start position:0% +says that this kind of inequality should + + + align:start position:0% +says that this kind of inequality should +be true whenever you replace c4 by any + + align:start position:0% +be true whenever you replace c4 by any + + + align:start position:0% +be true whenever you replace c4 by any +bipartite graph and that's a major open + + align:start position:0% +bipartite graph and that's a major open + + + align:start position:0% +bipartite graph and that's a major open +problem in combinatorics it's kind of + + align:start position:0% +problem in combinatorics it's kind of + + + align:start position:0% +problem in combinatorics it's kind of +hard to keep track of these calculations + + align:start position:0% +hard to keep track of these calculations + + + align:start position:0% +hard to keep track of these calculations +unless you have a visual anchor and this + + align:start position:0% +unless you have a visual anchor and this + + + align:start position:0% +unless you have a visual anchor and this +is my visual anchor which I'm trying to + + align:start position:0% +is my visual anchor which I'm trying to + + + align:start position:0% +is my visual anchor which I'm trying to +explain + + align:start position:0% +explain + + + align:start position:0% +explain +of course it's down-to-earth it's just + + align:start position:0% +of course it's down-to-earth it's just + + + align:start position:0% +of course it's down-to-earth it's just +the sequence of inequalities and this is + + align:start position:0% +the sequence of inequalities and this is + + + align:start position:0% +the sequence of inequalities and this is +also some practice with cauchy-schwarz + + align:start position:0% + + + + align:start position:0% + +alright any questions so but one thing + + align:start position:0% +alright any questions so but one thing + + + align:start position:0% +alright any questions so but one thing +in this calculation told us is that if + + align:start position:0% +in this calculation told us is that if + + + align:start position:0% +in this calculation told us is that if +you have edge density P then you + + align:start position:0% +you have edge density P then you + + + align:start position:0% +you have edge density P then you +necessarily have c4 density at least P + + align:start position:0% +necessarily have c4 density at least P + + + align:start position:0% +necessarily have c4 density at least P +to the fourth so that party explains why + + align:start position:0% +to the fourth so that party explains why + + + align:start position:0% +to the fourth so that party explains why +you have at most n here so you always + + align:start position:0% +you have at most n here so you always + + + align:start position:0% +you have at most n here so you always +know that it is at least this quantity + + align:start position:0% +know that it is at least this quantity + + + align:start position:0% +know that it is at least this quantity +so the c-4 quasi randomness condition + + align:start position:0% +so the c-4 quasi randomness condition + + + align:start position:0% +so the c-4 quasi randomness condition +it's really the equivalent to replacing + + align:start position:0% +it's really the equivalent to replacing + + + align:start position:0% +it's really the equivalent to replacing +this less than or equal to u by an equal + + align:start position:0% +this less than or equal to u by an equal + + + align:start position:0% +this less than or equal to u by an equal +sign ok so let's get started with + + align:start position:0% +sign ok so let's get started with + + + align:start position:0% +sign ok so let's get started with +proving the chunk um Wilson theorem so + + align:start position:0% +proving the chunk um Wilson theorem so + + + align:start position:0% +proving the chunk um Wilson theorem so +the first place that we'll look at is + + align:start position:0% +the first place that we'll look at is + + + align:start position:0% +the first place that we'll look at is +the two versions of disk disk stands for + + align:start position:0% +the two versions of disk disk stands for + + + align:start position:0% +the two versions of disk disk stands for +discrepancy okay so first fact that disk + + align:start position:0% +discrepancy okay so first fact that disk + + + align:start position:0% +discrepancy okay so first fact that disk +implies this prime I mean this is pretty + + align:start position:0% +implies this prime I mean this is pretty + + + align:start position:0% +implies this prime I mean this is pretty +easy you take Y 2 equal to X be slightly + + align:start position:0% +easy you take Y 2 equal to X be slightly + + + align:start position:0% +easy you take Y 2 equal to X be slightly +careful about the definitions but you're + + align:start position:0% +careful about the definitions but you're + + + align:start position:0% +careful about the definitions but you're +okay not much to do that + + align:start position:0% +okay not much to do that + + + align:start position:0% +okay not much to do that +the other direction + + align:start position:0% + + + + align:start position:0% + +where you only have discrepancies for + + align:start position:0% +where you only have discrepancies for + + + align:start position:0% +where you only have discrepancies for +single sets and you want to produce + + align:start position:0% +single sets and you want to produce + + + align:start position:0% +single sets and you want to produce +discrepancies four pairs of sets ok so + + align:start position:0% +discrepancies four pairs of sets ok so + + + align:start position:0% +discrepancies four pairs of sets ok so +this is actually a fairly common + + align:start position:0% +this is actually a fairly common + + + align:start position:0% +this is actually a fairly common +technique in algebra that allows you to + + align:start position:0% +technique in algebra that allows you to + + + align:start position:0% +technique in algebra that allows you to +go from bilinear forms to quadratic + + align:start position:0% +go from bilinear forms to quadratic + + + align:start position:0% +go from bilinear forms to quadratic +forms and vice versa it's that kind of + + align:start position:0% +forms and vice versa it's that kind of + + + align:start position:0% +forms and vice versa it's that kind of +calculation so let me do it here + + align:start position:0% +calculation so let me do it here + + + align:start position:0% +calculation so let me do it here +concretely in this setting so here what + + align:start position:0% +concretely in this setting so here what + + + align:start position:0% +concretely in this setting so here what +you should think of is that you have two + + align:start position:0% +you should think of is that you have two + + + align:start position:0% +you should think of is that you have two +sets x and y and they might overlap and + + align:start position:0% +sets x and y and they might overlap and + + + align:start position:0% +sets x and y and they might overlap and +what they correspond to in the and you + + align:start position:0% +what they correspond to in the and you + + + align:start position:0% +what they correspond to in the and you +think about the corresponding Venn + + align:start position:0% +think about the corresponding Venn + + + align:start position:0% +think about the corresponding Venn +diagram where I am looking at ways that + + align:start position:0% +diagram where I am looking at ways that + + + align:start position:0% +diagram where I am looking at ways that +a vertex and fall in pair of vertices + + align:start position:0% +a vertex and fall in pair of vertices + + + align:start position:0% +a vertex and fall in pair of vertices +can fall in X and/or Y so if you have x + + align:start position:0% +can fall in X and/or Y so if you have x + + + align:start position:0% +can fall in X and/or Y so if you have x +and y and so it's useful to keep track + + align:start position:0% +and y and so it's useful to keep track + + + align:start position:0% +and y and so it's useful to keep track +of which vertices are in which set but + + align:start position:0% +of which vertices are in which set but + + + align:start position:0% +of which vertices are in which set but +what the thing finally comes down to is + + align:start position:0% +what the thing finally comes down to is + + + align:start position:0% +what the thing finally comes down to is +that the number of edges with one vertex + + align:start position:0% +that the number of edges with one vertex + + + align:start position:0% +that the number of edges with one vertex +in X on one vertex in Y I can write this + + align:start position:0% +in X on one vertex in Y I can write this + + + align:start position:0% +in X on one vertex in Y I can write this +bilinear form type quantity as a course + + align:start position:0% +bilinear form type quantity as a course + + + align:start position:0% +bilinear form type quantity as a course +as an appropriate some just number of + + align:start position:0% +as an appropriate some just number of + + + align:start position:0% +as an appropriate some just number of +edges in single sets okay so there are + + align:start position:0% +edges in single sets okay so there are + + + align:start position:0% +edges in single sets okay so there are +several ways to check that this is true + + align:start position:0% +several ways to check that this is true + + + align:start position:0% +several ways to check that this is true +one way is to just tally and keep track + + align:start position:0% +one way is to just tally and keep track + + + align:start position:0% +one way is to just tally and keep track +of how many edges are you counting in + + align:start position:0% +of how many edges are you counting in + + + align:start position:0% +of how many edges are you counting in +each step so if you are trying to count + + align:start position:0% + + + + align:start position:0% + +the number of edges in yeah so let's say + + align:start position:0% +the number of edges in yeah so let's say + + + align:start position:0% +the number of edges in yeah so let's say +if you're trying to count the number of + + align:start position:0% +if you're trying to count the number of + + + align:start position:0% +if you're trying to count the number of +edges in with one vertex in x one vertex + + align:start position:0% +edges in with one vertex in x one vertex + + + align:start position:0% +edges in with one vertex in x one vertex +in Y then what this corresponds to is + + align:start position:0% +in Y then what this corresponds to is + + + align:start position:0% +in Y then what this corresponds to is +that count but let me do a reflection + + align:start position:0% + + + + align:start position:0% + +and then you see that you can write this + + align:start position:0% +and then you see that you can write this + + + align:start position:0% +and then you see that you can write this +some say alternating sum of principal + + align:start position:0% +some say alternating sum of principal + + + align:start position:0% +some say alternating sum of principal +squares so this one big square plus the + + align:start position:0% +squares so this one big square plus the + + + align:start position:0% +squares so this one big square plus the +middle square and minus the 2 side + + align:start position:0% +middle square and minus the 2 side + + + align:start position:0% +middle square and minus the 2 side +squares which is what that sum comes to + + align:start position:0% +squares which is what that sum comes to + + + align:start position:0% +squares which is what that sum comes to +alright so if we assume this prime then + + align:start position:0% +alright so if we assume this prime then + + + align:start position:0% +alright so if we assume this prime then +I know that all of these individual sets + + align:start position:0% +I know that all of these individual sets + + + align:start position:0% +I know that all of these individual sets +have roughly the correct number of edges + + align:start position:0% + + + + align:start position:0% + +up to a little o of n squared error and + + align:start position:0% +up to a little o of n squared error and + + + align:start position:0% +up to a little o of n squared error and +again like I don't have to do this + + align:start position:0% +again like I don't have to do this + + + align:start position:0% +again like I don't have to do this +calculation again because it's the same + + align:start position:0% +calculation again because it's the same + + + align:start position:0% +calculation again because it's the same +calculation so the final thing should be + + align:start position:0% +calculation so the final thing should be + + + align:start position:0% +calculation so the final thing should be +P times the sizes of x and y together + + align:start position:0% +P times the sizes of x and y together + + + align:start position:0% +P times the sizes of x and y together +Plus this same error ok so that shows + + align:start position:0% +Plus this same error ok so that shows + + + align:start position:0% +Plus this same error ok so that shows +you this prime implies disk so the self + + align:start position:0% +you this prime implies disk so the self + + + align:start position:0% +you this prime implies disk so the self +version of discrepancy implies the pair + + align:start position:0% +version of discrepancy implies the pair + + + align:start position:0% +version of discrepancy implies the pair +version and discrepancy so let's move on + + align:start position:0% +version and discrepancy so let's move on + + + align:start position:0% +version and discrepancy so let's move on +to count + + align:start position:0% + + + + align:start position:0% + +to show that disk implies count actually + + align:start position:0% +to show that disk implies count actually + + + align:start position:0% +to show that disk implies count actually +we already did this so this is the + + align:start position:0% +we already did this so this is the + + + align:start position:0% +we already did this so this is the +counting lemma so the counting lemma + + align:start position:0% +counting lemma so the counting lemma + + + align:start position:0% +counting lemma so the counting lemma +tells us how to count labelled copies if + + align:start position:0% +tells us how to count labelled copies if + + + align:start position:0% +tells us how to count labelled copies if +you have these epsilon regularity + + align:start position:0% +you have these epsilon regularity + + + align:start position:0% +you have these epsilon regularity +conditions which is exactly what this + + align:start position:0% +conditions which is exactly what this + + + align:start position:0% +conditions which is exactly what this +case so so count is good + + align:start position:0% +case so so count is good + + + align:start position:0% +case so so count is good +another easy implication + + align:start position:0% +another easy implication + + + align:start position:0% +another easy implication +yes can implies c4 or this is actually + + align:start position:0% +yes can implies c4 or this is actually + + + align:start position:0% +yes can implies c4 or this is actually +just tautological c4 condition is a + + align:start position:0% +just tautological c4 condition is a + + + align:start position:0% +just tautological c4 condition is a +special case of of the count hypothesis + + align:start position:0% + + + + align:start position:0% + +all right so let's move on to some + + align:start position:0% +all right so let's move on to some + + + align:start position:0% +all right so let's move on to some +additional implications that require a + + align:start position:0% +additional implications that require a + + + align:start position:0% +additional implications that require a +bit more work so what about c4 implies + + align:start position:0% +bit more work so what about c4 implies + + + align:start position:0% +bit more work so what about c4 implies +Co degree so this is where we need to do + + align:start position:0% +Co degree so this is where we need to do + + + align:start position:0% +Co degree so this is where we need to do +this kind of Cauchy Schwarz exercise so + + align:start position:0% +this kind of Cauchy Schwarz exercise so + + + align:start position:0% +this kind of Cauchy Schwarz exercise so +let's start with c4 so assume the c-4 + + align:start position:0% +let's start with c4 so assume the c-4 + + + align:start position:0% +let's start with c4 so assume the c-4 +condition and suppose you have this + + align:start position:0% + + + + align:start position:0% + +okay so let's so I want to deduce that + + align:start position:0% +okay so let's so I want to deduce that + + + align:start position:0% +okay so let's so I want to deduce that +the co degree condition is true but + + align:start position:0% +the co degree condition is true but + + + align:start position:0% +the co degree condition is true but +first let's think about just what is the + + align:start position:0% +first let's think about just what is the + + + align:start position:0% +first let's think about just what is the +sum of these Co degrees as I vary U and + + align:start position:0% +sum of these Co degrees as I vary U and + + + align:start position:0% +sum of these Co degrees as I vary U and +V over all pairs of vertices + + align:start position:0% + + + + align:start position:0% + +so this is the a picture so that is + + align:start position:0% +so this is the a picture so that is + + + align:start position:0% +so this is the a picture so that is +equal to the sums of degrees squared + + align:start position:0% +equal to the sums of degrees squared + + + align:start position:0% +equal to the sums of degrees squared +which now by cauchy-schwarz you can + + align:start position:0% +which now by cauchy-schwarz you can + + + align:start position:0% +which now by cauchy-schwarz you can +reduce to be at least n times 2 raised + + align:start position:0% +reduce to be at least n times 2 raised + + + align:start position:0% +reduce to be at least n times 2 raised +to the number of edges namely the sum of + + align:start position:0% +to the number of edges namely the sum of + + + align:start position:0% +to the number of edges namely the sum of +the degrees + + align:start position:0% +the degrees + + + align:start position:0% +the degrees +I think squared so now we assumed the + + align:start position:0% +I think squared so now we assumed the + + + align:start position:0% +I think squared so now we assumed the +c-4 condition actually we assume that G + + align:start position:0% +c-4 condition actually we assume that G + + + align:start position:0% +c-4 condition actually we assume that G +has the density yes written up there so + + align:start position:0% +has the density yes written up there so + + + align:start position:0% +has the density yes written up there so +this quantity is P squared plus Pluto 1 + + align:start position:0% +this quantity is P squared plus Pluto 1 + + + align:start position:0% +this quantity is P squared plus Pluto 1 +times n which is what you should expect + + align:start position:0% +times n which is what you should expect + + + align:start position:0% +times n which is what you should expect +in a random graph of GMP okay so that's + + align:start position:0% +in a random graph of GMP okay so that's + + + align:start position:0% +in a random graph of GMP okay so that's +but that's not quite what we're looking + + align:start position:0% +but that's not quite what we're looking + + + align:start position:0% +but that's not quite what we're looking +for okay so this is just the sum of the + + align:start position:0% +for okay so this is just the sum of the + + + align:start position:0% +for okay so this is just the sum of the +co degrees what we actually want is the + + align:start position:0% +co degrees what we actually want is the + + + align:start position:0% +co degrees what we actually want is the +deviation of co degrees from its + + align:start position:0% +deviation of co degrees from its + + + align:start position:0% +deviation of co degrees from its +expectation so to speak you know here's + + align:start position:0% +expectation so to speak you know here's + + + align:start position:0% +expectation so to speak you know here's +a important technique from probabilistic + + align:start position:0% +a important technique from probabilistic + + + align:start position:0% +a important technique from probabilistic +component works is that if you want to + + align:start position:0% +component works is that if you want to + + + align:start position:0% +component works is that if you want to +control the deviation of a random + + align:start position:0% +control the deviation of a random + + + align:start position:0% +control the deviation of a random +variable one thing should look at is the + + align:start position:0% +variable one thing should look at is the + + + align:start position:0% +variable one thing should look at is the +variance so if you can control the + + align:start position:0% +variance so if you can control the + + + align:start position:0% +variance so if you can control the +variance then you can control the + + align:start position:0% +variance then you can control the + + + align:start position:0% +variance then you can control the +deviation and this is a method known as + + align:start position:0% +deviation and this is a method known as + + + align:start position:0% +deviation and this is a method known as +the second moment method and that's what + + align:start position:0% +the second moment method and that's what + + + align:start position:0% +the second moment method and that's what +we're going to do here so what we'll try + + align:start position:0% +we're going to do here so what we'll try + + + align:start position:0% +we're going to do here so what we'll try +to show is that the second moment of + + align:start position:0% + + + + align:start position:0% + +this code agrees a meter + + align:start position:0% +this code agrees a meter + + + align:start position:0% +this code agrees a meter +sum of their squares it's also what you + + align:start position:0% +sum of their squares it's also what you + + + align:start position:0% +sum of their squares it's also what you +should expect as if the random setting + + align:start position:0% +should expect as if the random setting + + + align:start position:0% +should expect as if the random setting +and then you can put them together to + + align:start position:0% +and then you can put them together to + + + align:start position:0% +and then you can put them together to +show what you want so this quantity here + + align:start position:0% +show what you want so this quantity here + + + align:start position:0% +show what you want so this quantity here +well what is this we just saw see up + + align:start position:0% +well what is this we just saw see up + + + align:start position:0% +well what is this we just saw see up +there it's also called degree square + + align:start position:0% +there it's also called degree square + + + align:start position:0% +there it's also called degree square +squared so this quantity is also the + + align:start position:0% +squared so this quantity is also the + + + align:start position:0% +squared so this quantity is also the +number of labeled copies of c4 + + align:start position:0% + + + + align:start position:0% + +not quite because you might have two + + align:start position:0% +not quite because you might have two + + + align:start position:0% +not quite because you might have two +vertices and the amber at the same + + align:start position:0% +vertices and the amber at the same + + + align:start position:0% +vertices and the amber at the same +vertex so I incorporate a small error so + + align:start position:0% +vertex so I incorporate a small error so + + + align:start position:0% +vertex so I incorporate a small error so +it's really a sub it's a cubic error but + + align:start position:0% +it's really a sub it's a cubic error but + + + align:start position:0% +it's really a sub it's a cubic error but +certainly sub n to the fourth and we + + align:start position:0% +certainly sub n to the fourth and we + + + align:start position:0% +certainly sub n to the fourth and we +assume that the number of labeled copies + + align:start position:0% +assume that the number of labeled copies + + + align:start position:0% +assume that the number of labeled copies +of c-4 by the support condition is no + + align:start position:0% +of c-4 by the support condition is no + + + align:start position:0% +of c-4 by the support condition is no +more than basically P to the 4 times and + + align:start position:0% +more than basically P to the 4 times and + + + align:start position:0% +more than basically P to the 4 times and +raise to the power 4 okay so now you + + align:start position:0% +raise to the power 4 okay so now you + + + align:start position:0% +raise to the power 4 okay so now you +have a first moment for some average and + + align:start position:0% +have a first moment for some average and + + + align:start position:0% +have a first moment for some average and +you have some control in the second + + align:start position:0% +you have some control in the second + + + align:start position:0% +you have some control in the second +moment I can put them together to bound + + align:start position:0% +moment I can put them together to bound + + + align:start position:0% +moment I can put them together to bound +the deviation using this idea of + + align:start position:0% +the deviation using this idea of + + + align:start position:0% +the deviation using this idea of +controlling variance code degree + + align:start position:0% + + + + align:start position:0% + +deviation is upper bounded by okay so + + align:start position:0% +deviation is upper bounded by okay so + + + align:start position:0% +deviation is upper bounded by okay so +here using Cauchy Schwartz it's upper + + align:start position:0% +here using Cauchy Schwartz it's upper + + + align:start position:0% +here using Cauchy Schwartz it's upper +bounded by basically the same sum except + + align:start position:0% +bounded by basically the same sum except + + + align:start position:0% +bounded by basically the same sum except +I want to square the summoned this also + + align:start position:0% +I want to square the summoned this also + + + align:start position:0% +I want to square the summoned this also +gets rid of the pesky absolute value + + align:start position:0% +gets rid of the pesky absolute value + + + align:start position:0% +gets rid of the pesky absolute value +sign which is not nicely algebraically + + align:start position:0% +sign which is not nicely algebraically + + + align:start position:0% +sign which is not nicely algebraically +behaved now at the square and I can + + align:start position:0% +behaved now at the square and I can + + + align:start position:0% +behaved now at the square and I can +expand the square + + align:start position:0% + + + + align:start position:0% + +okay so I expand the square into these + + align:start position:0% +okay so I expand the square into these + + + align:start position:0% +okay so I expand the square into these +terms and the final term here it's P 2 4 + + align:start position:0% +terms and the final term here it's P 2 4 + + + align:start position:0% +terms and the final term here it's P 2 4 +& 6 all right but I have controlled + + align:start position:0% +& 6 all right but I have controlled + + + align:start position:0% +& 6 all right but I have controlled +individual terms from the calculations + + align:start position:0% +individual terms from the calculations + + + align:start position:0% +individual terms from the calculations +above so I can upper bound this + + align:start position:0% +above so I can upper bound this + + + align:start position:0% +above so I can upper bound this +expression by what I'm writing down now + + align:start position:0% + + + + align:start position:0% + +and basically you should expect that + + align:start position:0% +and basically you should expect that + + + align:start position:0% +and basically you should expect that +everything should cancel out because + + align:start position:0% +everything should cancel out because + + + align:start position:0% +everything should cancel out because +they do cancel all in a random case but + + align:start position:0% +they do cancel all in a random case but + + + align:start position:0% +they do cancel all in a random case but +of course it's a sin if you check it's + + align:start position:0% +of course it's a sin if you check it's + + + align:start position:0% +of course it's a sin if you check it's +it's important to write down this + + align:start position:0% +it's important to write down this + + + align:start position:0% +it's important to write down this +calculation so if everything works all + + align:start position:0% +calculation so if everything works all + + + align:start position:0% +calculation so if everything works all +right everything should cancel out and + + align:start position:0% +right everything should cancel out and + + + align:start position:0% +right everything should cancel out and +indeed it you cancel out and you get + + align:start position:0% + + + + align:start position:0% + +this so everything should cancel out and + + align:start position:0% +this so everything should cancel out and + + + align:start position:0% +this so everything should cancel out and +you get a little o of n cubed I have to + + align:start position:0% +you get a little o of n cubed I have to + + + align:start position:0% +you get a little o of n cubed I have to +summarize in this implication from c42 + + align:start position:0% +summarize in this implication from c42 + + + align:start position:0% +summarize in this implication from c42 +to Co degree what we're doing is were + + align:start position:0% +to Co degree what we're doing is were + + + align:start position:0% +to Co degree what we're doing is were +controlling the variance of Co degrees + + align:start position:0% +controlling the variance of Co degrees + + + align:start position:0% +controlling the variance of Co degrees +using the c4 condition and a second + + align:start position:0% +using the c4 condition and a second + + + align:start position:0% +using the c4 condition and a second +moment bound showing that the c-4 + + align:start position:0% +moment bound showing that the c-4 + + + align:start position:0% +moment bound showing that the c-4 +condition you know trumps over to a col + + align:start position:0% +condition you know trumps over to a col + + + align:start position:0% +condition you know trumps over to a col +degree condition + + align:start position:0% + + + + align:start position:0% + +any questions so far okay so I'll let + + align:start position:0% +any questions so far okay so I'll let + + + align:start position:0% +any questions so far okay so I'll let +you ponder in this calculation the next + + align:start position:0% +you ponder in this calculation the next + + + align:start position:0% +you ponder in this calculation the next +one that will do is Co degree implies + + align:start position:0% +one that will do is Co degree implies + + + align:start position:0% +one that will do is Co degree implies +disk okay and that will be a calculation + + align:start position:0% +disk okay and that will be a calculation + + + align:start position:0% +disk okay and that will be a calculation +in a very similar flavor but it will be + + align:start position:0% +in a very similar flavor but it will be + + + align:start position:0% +in a very similar flavor but it will be +a slightly longer by a similar flavor + + align:start position:0% +a slightly longer by a similar flavor + + + align:start position:0% +a slightly longer by a similar flavor +calculation so let me do that after the + + align:start position:0% +calculation so let me do that after the + + + align:start position:0% +calculation so let me do that after the +break alright so what we've done so far + + align:start position:0% +break alright so what we've done so far + + + align:start position:0% +break alright so what we've done so far +so let's summarize the chain of + + align:start position:0% +so let's summarize the chain of + + + align:start position:0% +so let's summarize the chain of +implications that we have already proved + + align:start position:0% +implications that we have already proved + + + align:start position:0% +implications that we have already proved +so first we started with showing that + + align:start position:0% +so first we started with showing that + + + align:start position:0% +so first we started with showing that +the two versions of disk are equivalent + + align:start position:0% + + + + align:start position:0% + +and then we also noticed that disk + + align:start position:0% +and then we also noticed that disk + + + align:start position:0% +and then we also noticed that disk +implies count through the counting lemma + + align:start position:0% +implies count through the counting lemma + + + align:start position:0% +implies count through the counting lemma +so we also observe that count implies c4 + + align:start position:0% +so we also observe that count implies c4 + + + align:start position:0% +so we also observe that count implies c4 +tautologically and c-4 implies code + + align:start position:0% +tautologically and c-4 implies code + + + align:start position:0% +tautologically and c-4 implies code +agree okay so the next natural thing to + + align:start position:0% +agree okay so the next natural thing to + + + align:start position:0% +agree okay so the next natural thing to +do is to complete this circuit and show + + align:start position:0% +do is to complete this circuit and show + + + align:start position:0% +do is to complete this circuit and show +that the code agree condition implies + + align:start position:0% +that the code agree condition implies + + + align:start position:0% +that the code agree condition implies +that the discrepancy condition so that's + + align:start position:0% +that the discrepancy condition so that's + + + align:start position:0% +that the discrepancy condition so that's +what we do next and in some sense you + + align:start position:0% +what we do next and in some sense you + + + align:start position:0% +what we do next and in some sense you +know these two steps you should think of + + align:start position:0% +know these two steps you should think of + + + align:start position:0% +know these two steps you should think of +them as going in this natural chain + + align:start position:0% +them as going in this natural chain + + + align:start position:0% +them as going in this natural chain +where C 4 so C 4 is 4 like this C 4 code + + align:start position:0% +where C 4 so C 4 is 4 like this C 4 code + + + align:start position:0% +where C 4 so C 4 is 4 like this C 4 code +agree condition is really about that and + + align:start position:0% +agree condition is really about that and + + + align:start position:0% +agree condition is really about that and +disk it's really about single edges as + + align:start position:0% +disk it's really about single edges as + + + align:start position:0% +disk it's really about single edges as +you can go from top if you you have you + + align:start position:0% +you can go from top if you you have you + + + align:start position:0% +you can go from top if you you have you +you get much more power so it's going in + + align:start position:0% +you get much more power so it's going in + + + align:start position:0% +you get much more power so it's going in +the right direction going downstream so + + align:start position:0% +the right direction going downstream so + + + align:start position:0% +the right direction going downstream so +to speak so that's what we're doing now + + align:start position:0% +to speak so that's what we're doing now + + + align:start position:0% +to speak so that's what we're doing now +going downstream and then you go + + align:start position:0% +going downstream and then you go + + + align:start position:0% +going downstream and then you go +upstream via the counting number all + + align:start position:0% +upstream via the counting number all + + + align:start position:0% +upstream via the counting number all +right + + align:start position:0% +right + + + align:start position:0% +right +let's do code degree implies disk so we + + align:start position:0% +let's do code degree implies disk so we + + + align:start position:0% +let's do code degree implies disk so we +want to show the discrepancy condition + + align:start position:0% +want to show the discrepancy condition + + + align:start position:0% +want to show the discrepancy condition +which is one written up there but before + + align:start position:0% +which is one written up there but before + + + align:start position:0% +which is one written up there but before +that let me first show you that the + + align:start position:0% +that let me first show you that the + + + align:start position:0% +that let me first show you that the +degrees do not vary too much so that the + + align:start position:0% +degrees do not vary too much so that the + + + align:start position:0% +degrees do not vary too much so that the +degrees are fairly well distributed + + align:start position:0% +degrees are fairly well distributed + + + align:start position:0% +degrees are fairly well distributed +which is what you should expect in a + + align:start position:0% +which is what you should expect in a + + + align:start position:0% +which is what you should expect in a +pseudo random graph right so you don't + + align:start position:0% +pseudo random graph right so you don't + + + align:start position:0% +pseudo random graph right so you don't +expect a half the vertices half into + + align:start position:0% +expect a half the vertices half into + + + align:start position:0% +expect a half the vertices half into +Greece twice the other half so that's + + align:start position:0% +Greece twice the other half so that's + + + align:start position:0% +Greece twice the other half so that's +the first thing I want to establish if + + align:start position:0% +the first thing I want to establish if + + + align:start position:0% +the first thing I want to establish if +you look at degrees this variant this + + align:start position:0% +you look at degrees this variant this + + + align:start position:0% +you look at degrees this variant this +this deviation is it's not too big okay + + align:start position:0% +this deviation is it's not too big okay + + + align:start position:0% +this deviation is it's not too big okay +so like before we've seen absolute value + + align:start position:0% +so like before we've seen absolute value + + + align:start position:0% +so like before we've seen absolute value +sign we see some so what do you coffee + + align:start position:0% +sign we see some so what do you coffee + + + align:start position:0% +sign we see some so what do you coffee +shorts coffee Schwartz allows us to + + align:start position:0% +shorts coffee Schwartz allows us to + + + align:start position:0% +shorts coffee Schwartz allows us to +bound this quantity replacing the + + align:start position:0% +bound this quantity replacing the + + + align:start position:0% +bound this quantity replacing the +summoned by a sum of squared + + align:start position:0% + + + + align:start position:0% + +a square so I can expand the square so + + align:start position:0% +a square so I can expand the square so + + + align:start position:0% +a square so I can expand the square so +let me expand the square I get that + + align:start position:0% +let me expand the square I get that + + + align:start position:0% +let me expand the square I get that +so just expanding this square inside and + + align:start position:0% +so just expanding this square inside and + + + align:start position:0% +so just expanding this square inside and +you see this degree squared is that + + align:start position:0% +you see this degree squared is that + + + align:start position:0% +you see this degree squared is that +picture so that's some of code degrees + + align:start position:0% + + + + align:start position:0% + +and some of the degrees is just a number + + align:start position:0% +and some of the degrees is just a number + + + align:start position:0% +and some of the degrees is just a number +of edges + + align:start position:0% + + + + align:start position:0% + +okay but we now assume the code agree + + align:start position:0% +okay but we now assume the code agree + + + align:start position:0% +okay but we now assume the code agree +condition which in particular implies + + align:start position:0% +condition which in particular implies + + + align:start position:0% +condition which in particular implies +that the sum the code agrees is roughly + + align:start position:0% +that the sum the code agrees is roughly + + + align:start position:0% +that the sum the code agrees is roughly +what you expect so the sum of the code + + align:start position:0% +what you expect so the sum of the code + + + align:start position:0% +what you expect so the sum of the code +agrees should be P Square and cubed plus + + align:start position:0% +agrees should be P Square and cubed plus + + + align:start position:0% +agrees should be P Square and cubed plus +a little ol and cube error at the end + + align:start position:0% +a little ol and cube error at the end + + + align:start position:0% +a little ol and cube error at the end +likewise the number of edges is by + + align:start position:0% +likewise the number of edges is by + + + align:start position:0% +likewise the number of edges is by +assumption what you would expect in a + + align:start position:0% +assumption what you would expect in a + + + align:start position:0% +assumption what you would expect in a +random graph and then a final term and + + align:start position:0% +random graph and then a final term and + + + align:start position:0% +random graph and then a final term and +like before of course it's good to do it + + align:start position:0% +like before of course it's good to do it + + + align:start position:0% +like before of course it's good to do it +since then if you check everything + + align:start position:0% +since then if you check everything + + + align:start position:0% +since then if you check everything +should cancel out so what you end up + + align:start position:0% +should cancel out so what you end up + + + align:start position:0% +should cancel out so what you end up +with is little o of N squared showing + + align:start position:0% +with is little o of N squared showing + + + align:start position:0% +with is little o of N squared showing +that the degrees do not vary too much + + align:start position:0% +that the degrees do not vary too much + + + align:start position:0% +that the degrees do not vary too much +and once you have that promise then we + + align:start position:0% +and once you have that promise then we + + + align:start position:0% +and once you have that promise then we +move on to the actual discrepancy + + align:start position:0% +move on to the actual discrepancy + + + align:start position:0% +move on to the actual discrepancy +condition so this discrepancy is can be + + align:start position:0% +condition so this discrepancy is can be + + + align:start position:0% +condition so this discrepancy is can be +rewritten as the sum over vertices + + align:start position:0% +rewritten as the sum over vertices + + + align:start position:0% +rewritten as the sum over vertices +little X in big x degree from little X + + align:start position:0% +little X in big x degree from little X + + + align:start position:0% +little X in big x degree from little X +to Y minus key times the size of y okay + + align:start position:0% +to Y minus key times the size of y okay + + + align:start position:0% +to Y minus key times the size of y okay +so rewriting this sum of course what + + align:start position:0% +so rewriting this sum of course what + + + align:start position:0% +so rewriting this sum of course what +should we do next + + align:start position:0% +should we do next + + + align:start position:0% +should we do next +Cosi sorts great so what do you call + + align:start position:0% +Cosi sorts great so what do you call + + + align:start position:0% +Cosi sorts great so what do you call +shorts okay so here's a here's a + + align:start position:0% +shorts okay so here's a here's a + + + align:start position:0% +shorts okay so here's a here's a +important step or a trick if you will so + + align:start position:0% +important step or a trick if you will so + + + align:start position:0% +important step or a trick if you will so +what do you coach is shorts and + + align:start position:0% +what do you coach is shorts and + + + align:start position:0% +what do you coach is shorts and +something very nice happens we need your + + align:start position:0% +something very nice happens we need your + + + align:start position:0% +something very nice happens we need your +coffee shorts here instead okay so you + + align:start position:0% +coffee shorts here instead okay so you + + + align:start position:0% +coffee shorts here instead okay so you +can write down the expression that you + + align:start position:0% +can write down the expression that you + + + align:start position:0% +can write down the expression that you +obtain when you do coffee shorts so we + + align:start position:0% +obtain when you do coffee shorts so we + + + align:start position:0% +obtain when you do coffee shorts so we +do that first + + align:start position:0% + + + + align:start position:0% + +okay so here's a step which is very easy + + align:start position:0% +okay so here's a step which is very easy + + + align:start position:0% +okay so here's a step which is very easy +to cross over but I want to pause and + + align:start position:0% +to cross over but I want to pause and + + + align:start position:0% +to cross over but I want to pause and +emphasize this step because this is + + align:start position:0% +emphasize this step because this is + + + align:start position:0% +emphasize this step because this is +actually really important what I'm going + + align:start position:0% +actually really important what I'm going + + + align:start position:0% +actually really important what I'm going +to do now is to observe that the summon + + align:start position:0% +to do now is to observe that the summon + + + align:start position:0% +to do now is to observe that the summon +is always non-negative therefore I can + + align:start position:0% +is always non-negative therefore I can + + + align:start position:0% +is always non-negative therefore I can +enlarge the sum from just little X in X + + align:start position:0% +enlarge the sum from just little X in X + + + align:start position:0% +enlarge the sum from just little X in X +to the entire vertex set and this is + + align:start position:0% +to the entire vertex set and this is + + + align:start position:0% +to the entire vertex set and this is +important right so this is important + + align:start position:0% +important right so this is important + + + align:start position:0% +important right so this is important +that we had to do coffee shorts first to + + align:start position:0% +that we had to do coffee shorts first to + + + align:start position:0% +that we had to do coffee shorts first to +get a non negative someone you couldn't + + align:start position:0% +get a non negative someone you couldn't + + + align:start position:0% +get a non negative someone you couldn't +do this in the beginning so you do that + + align:start position:0% +do this in the beginning so you do that + + + align:start position:0% +do this in the beginning so you do that +and okay so I have this sum of squares + + align:start position:0% +and okay so I have this sum of squares + + + align:start position:0% +and okay so I have this sum of squares +so I expand expand I write out all these + + align:start position:0% +so I expand expand I write out all these + + + align:start position:0% +so I expand expand I write out all these +expressions + + align:start position:0% + + + + align:start position:0% + +and now the little x-range over the + + align:start position:0% +and now the little x-range over the + + + align:start position:0% +and now the little x-range over the +entire vertex set all right so what was + + align:start position:0% +entire vertex set all right so what was + + + align:start position:0% +entire vertex set all right so what was +the point of all of that so you see this + + align:start position:0% +the point of all of that so you see this + + + align:start position:0% +the point of all of that so you see this +expression here the degree of from + + align:start position:0% +expression here the degree of from + + + align:start position:0% +expression here the degree of from +little X to big Y squared okay so what + + align:start position:0% +little X to big Y squared okay so what + + + align:start position:0% +little X to big Y squared okay so what +is that how can we rewrite this + + align:start position:0% +is that how can we rewrite this + + + align:start position:0% +is that how can we rewrite this +expression + + align:start position:0% + + + + align:start position:0% + +honey little X Y squared + + align:start position:0% + + + + align:start position:0% + +yeah so some of code degree of two + + align:start position:0% +yeah so some of code degree of two + + + align:start position:0% +yeah so some of code degree of two +vertices in Y so Y Y prime in Y code + + align:start position:0% +vertices in Y so Y Y prime in Y code + + + align:start position:0% +vertices in Y so Y Y prime in Y code +degree of little Y little Y Prime and + + align:start position:0% + + + + align:start position:0% + +likewise the next expression can be + + align:start position:0% +likewise the next expression can be + + + align:start position:0% +likewise the next expression can be +written as the sum of the degrees of + + align:start position:0% +written as the sum of the degrees of + + + align:start position:0% +written as the sum of the degrees of +vertices in Y and the third term I leave + + align:start position:0% +vertices in Y and the third term I leave + + + align:start position:0% +vertices in Y and the third term I leave +unchanged so now we've gotten rid of + + align:start position:0% +unchanged so now we've gotten rid of + + + align:start position:0% +unchanged so now we've gotten rid of +these funny expressions we're just + + align:start position:0% +these funny expressions we're just + + + align:start position:0% +these funny expressions we're just +degree from the vertex to a set and we + + align:start position:0% +degree from the vertex to a set and we + + + align:start position:0% +degree from the vertex to a set and we +could do this because of this relaxation + + align:start position:0% +could do this because of this relaxation + + + align:start position:0% +could do this because of this relaxation +up here so that was that was the point + + align:start position:0% +up here so that was that was the point + + + align:start position:0% +up here so that was that was the point +we had to use this relaxation so now we + + align:start position:0% +we had to use this relaxation so now we + + + align:start position:0% +we had to use this relaxation so now we +get these Co degree terms but now + + align:start position:0% +get these Co degree terms but now + + + align:start position:0% +get these Co degree terms but now +because you have the Co degree terms and + + align:start position:0% +because you have the Co degree terms and + + + align:start position:0% +because you have the Co degree terms and +we assume the Co degree hypothesis we + + align:start position:0% +we assume the Co degree hypothesis we + + + align:start position:0% +we assume the Co degree hypothesis we +obtained that the sum is roughly what + + align:start position:0% +obtained that the sum is roughly what + + + align:start position:0% +obtained that the sum is roughly what +you expect as a random case because all + + align:start position:0% +you expect as a random case because all + + + align:start position:0% +you expect as a random case because all +the individual deviations do not add up + + align:start position:0% +the individual deviations do not add up + + + align:start position:0% +the individual deviations do not add up +to more than little and cubed + + align:start position:0% + + + + align:start position:0% + +that could agree some so what you expect + + align:start position:0% +that could agree some so what you expect + + + align:start position:0% +that could agree some so what you expect +and the next term is some of the grease + + align:start position:0% +and the next term is some of the grease + + + align:start position:0% +and the next term is some of the grease +it's also by what we did up there what + + align:start position:0% +it's also by what we did up there what + + + align:start position:0% +it's also by what we did up there what +you expect and finally third term and as + + align:start position:0% +you expect and finally third term and as + + + align:start position:0% +you expect and finally third term and as +earlier if you did everything correctly + + align:start position:0% +earlier if you did everything correctly + + + align:start position:0% +earlier if you did everything correctly +everything should cancel and they do and + + align:start position:0% +everything should cancel and they do and + + + align:start position:0% +everything should cancel and they do and +so what you get at the end is total of n + + align:start position:0% +so what you get at the end is total of n + + + align:start position:0% +so what you get at the end is total of n +square + + align:start position:0% + + + + align:start position:0% + +okay this completes this 4-cycle any + + align:start position:0% +okay this completes this 4-cycle any + + + align:start position:0% +okay this completes this 4-cycle any +questions so far + + align:start position:0% + + + + align:start position:0% + +okay so we're missing one more condition + + align:start position:0% +okay so we're missing one more condition + + + align:start position:0% +okay so we're missing one more condition +and that's the eigenvalue condition so + + align:start position:0% +and that's the eigenvalue condition so + + + align:start position:0% +and that's the eigenvalue condition so +so far everything had to deal with + + align:start position:0% +so far everything had to deal with + + + align:start position:0% +so far everything had to deal with +counting various things all right so + + align:start position:0% +counting various things all right so + + + align:start position:0% +counting various things all right so +what does eigenvalue have to do with + + align:start position:0% +what does eigenvalue have to do with + + + align:start position:0% +what does eigenvalue have to do with +anything + + align:start position:0% + + + + align:start position:0% + +so the eigenvalue condition is actually + + align:start position:0% +so the eigenvalue condition is actually + + + align:start position:0% +so the eigenvalue condition is actually +a particularly important one and we'll + + align:start position:0% +a particularly important one and we'll + + + align:start position:0% +a particularly important one and we'll +see more of this in the next lecture but + + align:start position:0% +see more of this in the next lecture but + + + align:start position:0% +see more of this in the next lecture but +let me first show you the equivalent + + align:start position:0% +let me first show you the equivalent + + + align:start position:0% +let me first show you the equivalent +implications so what we'll show is that + + align:start position:0% +implications so what we'll show is that + + + align:start position:0% +implications so what we'll show is that +the eigen gallery condition is the + + align:start position:0% +the eigen gallery condition is the + + + align:start position:0% +the eigen gallery condition is the +equivalent to the c-4 condition so + + align:start position:0% +equivalent to the c-4 condition so + + + align:start position:0% +equivalent to the c-4 condition so +that's that's the goal I'll show you + + align:start position:0% +that's that's the goal I'll show you + + + align:start position:0% +that's that's the goal I'll show you +covalent between I and c4 + + align:start position:0% + + + + align:start position:0% + +so first implies the c-4 condition + + align:start position:0% +so first implies the c-4 condition + + + align:start position:0% +so first implies the c-4 condition +because up to so instead of counting + + align:start position:0% +because up to so instead of counting + + + align:start position:0% +because up to so instead of counting +cforce which is a little bit actually + + align:start position:0% +cforce which is a little bit actually + + + align:start position:0% +cforce which is a little bit actually +not it's been annoying to do actual + + align:start position:0% +not it's been annoying to do actual + + + align:start position:0% +not it's been annoying to do actual +cforce just like earlier we want to + + align:start position:0% +cforce just like earlier we want to + + + align:start position:0% +cforce just like earlier we want to +consider homomorphic copies which are + + align:start position:0% +consider homomorphic copies which are + + + align:start position:0% +consider homomorphic copies which are +also labeled walks so closed walks of + + align:start position:0% +also labeled walks so closed walks of + + + align:start position:0% +also labeled walks so closed walks of +length 4 so up to a cubic error the + + align:start position:0% +length 4 so up to a cubic error the + + + align:start position:0% +length 4 so up to a cubic error the +number of labeled C force is given by + + align:start position:0% +number of labeled C force is given by + + + align:start position:0% +number of labeled C force is given by +the number of closed walks of length 4 + + align:start position:0% + + + + align:start position:0% + +which is equal to the trace of the + + align:start position:0% +which is equal to the trace of the + + + align:start position:0% +which is equal to the trace of the +fourth power of the adjacency matrix of + + align:start position:0% +fourth power of the adjacency matrix of + + + align:start position:0% +fourth power of the adjacency matrix of +this graph + + align:start position:0% + + + + align:start position:0% + +okay and the next thing is super + + align:start position:0% +okay and the next thing is super + + + align:start position:0% +okay and the next thing is super +important so the next thing is this is + + align:start position:0% +important so the next thing is this is + + + align:start position:0% +important so the next thing is this is +sometimes called the trace method that + + align:start position:0% +sometimes called the trace method that + + + align:start position:0% +sometimes called the trace method that +one important way that the eigenvalues + + align:start position:0% +one important way that the eigenvalues + + + align:start position:0% +one important way that the eigenvalues +of the spectrum of a graph or matrix + + align:start position:0% +of the spectrum of a graph or matrix + + + align:start position:0% +of the spectrum of a graph or matrix +relates to other combinatorial + + align:start position:0% +relates to other combinatorial + + + align:start position:0% +relates to other combinatorial +quantities is via this trace so we know + + align:start position:0% +quantities is via this trace so we know + + + align:start position:0% +quantities is via this trace so we know +that the trace of the fourth power is + + align:start position:0% +that the trace of the fourth power is + + + align:start position:0% +that the trace of the fourth power is +equal to the fourth moment of the + + align:start position:0% +equal to the fourth moment of the + + + align:start position:0% +equal to the fourth moment of the +eigenvalues okay so if you haven't seen + + align:start position:0% +eigenvalues okay so if you haven't seen + + + align:start position:0% +eigenvalues okay so if you haven't seen +a proof of this before I encourage you + + align:start position:0% +a proof of this before I encourage you + + + align:start position:0% +a proof of this before I encourage you +to go home and think about it so this is + + align:start position:0% +to go home and think about it so this is + + + align:start position:0% +to go home and think about it so this is +this is an important identity of course + + align:start position:0% +this is an important identity of course + + + align:start position:0% +this is an important identity of course +4 can be replaced by any number up here + + align:start position:0% +4 can be replaced by any number up here + + + align:start position:0% +4 can be replaced by any number up here +and well now you have the eigenvalue + + align:start position:0% +and well now you have the eigenvalue + + + align:start position:0% +and well now you have the eigenvalue +condition so i can estimate this sum + + align:start position:0% +condition so i can estimate this sum + + + align:start position:0% +condition so i can estimate this sum +there's a principal term namely lambda 1 + + align:start position:0% +there's a principal term namely lambda 1 + + + align:start position:0% +there's a principal term namely lambda 1 +right so that's the big term everything + + align:start position:0% +right so that's the big term everything + + + align:start position:0% +right so that's the big term everything +else is small and the smallness is + + align:start position:0% +else is small and the smallness is + + + align:start position:0% +else is small and the smallness is +supposed to capture pseudo randomness + + align:start position:0% +supposed to capture pseudo randomness + + + align:start position:0% +supposed to capture pseudo randomness +but the big term you have to analyze + + align:start position:0% +but the big term you have to analyze + + + align:start position:0% +but the big term you have to analyze +separately so the big term okay so let + + align:start position:0% +separately so the big term okay so let + + + align:start position:0% +separately so the big term okay so let +me write it out so the big term you know + + align:start position:0% +me write it out so the big term you know + + + align:start position:0% +me write it out so the big term you know +that it is P to the 4n to the 4 plus + + align:start position:0% +that it is P to the 4n to the 4 plus + + + align:start position:0% +that it is P to the 4n to the 4 plus +total of 4 ok so the next thing is what + + align:start position:0% +total of 4 ok so the next thing is what + + + align:start position:0% +total of 4 ok so the next thing is what +to do with the middle terms so we want + + align:start position:0% +to do with the middle terms so we want + + + align:start position:0% +to do with the middle terms so we want +to show that the contribution in total + + align:start position:0% +to show that the contribution in total + + + align:start position:0% +to show that the contribution in total +is not too big so what can we do well so + + align:start position:0% +is not too big so what can we do well so + + + align:start position:0% +is not too big so what can we do well so +let me first try something + + align:start position:0% +let me first try something + + + align:start position:0% +let me first try something +so first well see that each one of these + + align:start position:0% +so first well see that each one of these + + + align:start position:0% +so first well see that each one of these +guys is not too big so maybe let's pound + + align:start position:0% +guys is not too big so maybe let's pound + + + align:start position:0% +guys is not too big so maybe let's pound +each one of them by go to all of em so + + align:start position:0% +each one of them by go to all of em so + + + align:start position:0% +each one of them by go to all of em so +raise to 4 but then there n of them so + + align:start position:0% +raise to 4 but then there n of them so + + + align:start position:0% +raise to 4 but then there n of them so +you have to multiply by an extra n and + + align:start position:0% +you have to multiply by an extra n and + + + align:start position:0% +you have to multiply by an extra n and +that's too much that's not good enough + + align:start position:0% +that's too much that's not good enough + + + align:start position:0% +that's too much that's not good enough +so we cannot individually pound each one + + align:start position:0% +so we cannot individually pound each one + + + align:start position:0% +so we cannot individually pound each one +of them and this is a this is a novice + + align:start position:0% +of them and this is a this is a novice + + + align:start position:0% +of them and this is a this is a novice +mistake so this is something that will + + align:start position:0% +mistake so this is something that will + + + align:start position:0% +mistake so this is something that will +actually we'll see this type of + + align:start position:0% +actually we'll see this type of + + + align:start position:0% +actually we'll see this type of +calculation later on in the term when we + + align:start position:0% +calculation later on in the term when we + + + align:start position:0% +calculation later on in the term when we +discussed Roth theorem but you're not + + align:start position:0% +discussed Roth theorem but you're not + + + align:start position:0% +discussed Roth theorem but you're not +supposed to bound these terms individual + + align:start position:0% +supposed to bound these terms individual + + + align:start position:0% +supposed to bound these terms individual +the better way to do this or the correct + + align:start position:0% +the better way to do this or the correct + + + align:start position:0% +the better way to do this or the correct +way to do this is to pull out just a + + align:start position:0% +way to do this is to pull out just a + + + align:start position:0% +way to do this is to pull out just a +couple you know some but not all of + + align:start position:0% +couple you know some but not all of + + + align:start position:0% +couple you know some but not all of +these factors so it is upper bounded by + + align:start position:0% +these factors so it is upper bounded by + + + align:start position:0% +these factors so it is upper bounded by +you take max off in this case you can + + align:start position:0% +you take max off in this case you can + + + align:start position:0% +you take max off in this case you can +take out with one or two but you take + + align:start position:0% +take out with one or two but you take + + + align:start position:0% +take out with one or two but you take +out let's say in two factors and then + + align:start position:0% +out let's say in two factors and then + + + align:start position:0% +out let's say in two factors and then +you leave the remaining sum intact in + + align:start position:0% +you leave the remaining sum intact in + + + align:start position:0% +you leave the remaining sum intact in +fact I can leave I can even put lambda + + align:start position:0% +fact I can leave I can even put lambda + + + align:start position:0% +fact I can leave I can even put lambda +one back into the remaining so so so + + align:start position:0% +one back into the remaining so so so + + + align:start position:0% +one back into the remaining so so so +that is true so what I've written down + + align:start position:0% +that is true so what I've written down + + + align:start position:0% +that is true so what I've written down +is just true as inequality and now I + + align:start position:0% +is just true as inequality and now I + + + align:start position:0% +is just true as inequality and now I +apply the hypothesis on the sizes of the + + align:start position:0% +apply the hypothesis on the sizes of the + + + align:start position:0% +apply the hypothesis on the sizes of the +other lambdas so one I pulled out is + + align:start position:0% +other lambdas so one I pulled out is + + + align:start position:0% +other lambdas so one I pulled out is +little Olaf N squared and now what's the + + align:start position:0% +little Olaf N squared and now what's the + + + align:start position:0% +little Olaf N squared and now what's the +second sum that sum is the trace of a + + align:start position:0% +second sum that sum is the trace of a + + + align:start position:0% +second sum that sum is the trace of a +squared which is just the twice the + + align:start position:0% +squared which is just the twice the + + + align:start position:0% +squared which is just the twice the +number of edges of the graph so that's + + align:start position:0% +number of edges of the graph so that's + + + align:start position:0% +number of edges of the graph so that's +also at most N squared so combining + + align:start position:0% +also at most N squared so combining + + + align:start position:0% +also at most N squared so combining +everything you have the desired bound on + + align:start position:0% +everything you have the desired bound on + + + align:start position:0% +everything you have the desired bound on +the C for count of course this gives you + + align:start position:0% +the C for count of course this gives you + + + align:start position:0% +the C for count of course this gives you +an upper bound but we also did a + + align:start position:0% +an upper bound but we also did a + + + align:start position:0% +an upper bound but we also did a +calculation before the break that shows + + align:start position:0% +calculation before the break that shows + + + align:start position:0% +calculation before the break that shows +you that the C for bound is a lower + + align:start position:0% +you that the C for bound is a lower + + + align:start position:0% +you that the C for bound is a lower +bound as well so really having the + + align:start position:0% +bound as well so really having the + + + align:start position:0% +bound as well so really having the +correct + + align:start position:0% +correct + + + align:start position:0% +correct +I can value this already already shows + + align:start position:0% +I can value this already already shows + + + align:start position:0% +I can value this already already shows +you that the C for bound is correct in + + align:start position:0% +you that the C for bound is correct in + + + align:start position:0% +you that the C for bound is correct in +both directions but because we this is + + align:start position:0% +both directions but because we this is + + + align:start position:0% +both directions but because we this is +the main term and then everything else + + align:start position:0% +the main term and then everything else + + + align:start position:0% +the main term and then everything else +is small okay the final implication is C + + align:start position:0% +is small okay the final implication is C + + + align:start position:0% +is small okay the final implication is C +for implies eigen value + + align:start position:0% + + + + align:start position:0% + +okay for this one I need to explore this + + align:start position:0% +okay for this one I need to explore this + + + align:start position:0% +okay for this one I need to explore this +following important property of the top + + align:start position:0% +following important property of the top + + + align:start position:0% +following important property of the top +eigenvalue so this is something that we + + align:start position:0% +eigenvalue so this is something that we + + + align:start position:0% +eigenvalue so this is something that we +also saw last time which is the + + align:start position:0% +also saw last time which is the + + + align:start position:0% +also saw last time which is the +interpretation of the top eigen value of + + align:start position:0% +interpretation of the top eigen value of + + + align:start position:0% +interpretation of the top eigen value of +a matrix interpreted as so this is + + align:start position:0% +a matrix interpreted as so this is + + + align:start position:0% +a matrix interpreted as so this is +sometimes called the Kuran Fisher + + align:start position:0% +sometimes called the Kuran Fisher + + + align:start position:0% +sometimes called the Kuran Fisher +criterion or there actually this is a + + align:start position:0% +criterion or there actually this is a + + + align:start position:0% +criterion or there actually this is a +special case of Kuran Fisher okay this + + align:start position:0% +special case of Kuran Fisher okay this + + + align:start position:0% +special case of Kuran Fisher okay this +is a basic linear algebra fact if you + + align:start position:0% +is a basic linear algebra fact if you + + + align:start position:0% +is a basic linear algebra fact if you +are not familiar with it I recommend + + align:start position:0% +are not familiar with it I recommend + + + align:start position:0% +are not familiar with it I recommend +looking it up that the top eigen value + + align:start position:0% +looking it up that the top eigen value + + + align:start position:0% +looking it up that the top eigen value +of a matrix of a real symmetric matrix + + align:start position:0% + + + + align:start position:0% + +is characterized by the maximum value of + + align:start position:0% +is characterized by the maximum value of + + + align:start position:0% +is characterized by the maximum value of +this quadratic form let's say if X is a + + align:start position:0% +this quadratic form let's say if X is a + + + align:start position:0% +this quadratic form let's say if X is a +non zero vector so in particular if I + + align:start position:0% +non zero vector so in particular if I + + + align:start position:0% +non zero vector so in particular if I +set X to be a specific vector I can + + align:start position:0% +set X to be a specific vector I can + + + align:start position:0% +set X to be a specific vector I can +lower bound lambda 1 so if we set this + + align:start position:0% +lower bound lambda 1 so if we set this + + + align:start position:0% +lower bound lambda 1 so if we set this +boldface one to be the oh one vector in + + align:start position:0% +boldface one to be the oh one vector in + + + align:start position:0% +boldface one to be the oh one vector in +R raised to the number of vertices of G + + align:start position:0% +R raised to the number of vertices of G + + + align:start position:0% +R raised to the number of vertices of G +then the lambda one of the graph is at + + align:start position:0% +then the lambda one of the graph is at + + + align:start position:0% +then the lambda one of the graph is at +least this quantity over here the + + align:start position:0% +least this quantity over here the + + + align:start position:0% +least this quantity over here the +numerator and denominators are all easy + + align:start position:0% +numerator and denominators are all easy + + + align:start position:0% +numerator and denominators are all easy +things to evaluate the numerator is just + + align:start position:0% +things to evaluate the numerator is just + + + align:start position:0% +things to evaluate the numerator is just +twice the number of edges because you + + align:start position:0% +twice the number of edges because you + + + align:start position:0% +twice the number of edges because you +are summing up all the entries of the + + align:start position:0% +are summing up all the entries of the + + + align:start position:0% +are summing up all the entries of the +matrix and the new denominator is just n + + align:start position:0% +matrix and the new denominator is just n + + + align:start position:0% +matrix and the new denominator is just n +so the top eigenvalue is at least + + align:start position:0% +so the top eigenvalue is at least + + + align:start position:0% +so the top eigenvalue is at least +roughly PM + + align:start position:0% + + + + align:start position:0% + +okay so what about the other eigenvalues + + align:start position:0% + + + + align:start position:0% + +or the other eigenvalues I can again + + align:start position:0% +or the other eigenvalues I can again + + + align:start position:0% +or the other eigenvalues I can again +refer back to this moment formula + + align:start position:0% +refer back to this moment formula + + + align:start position:0% +refer back to this moment formula +relating a trace and closed walks it is + + align:start position:0% +relating a trace and closed walks it is + + + align:start position:0% +relating a trace and closed walks it is +at most the trace of the fourth power + + align:start position:0% +at most the trace of the fourth power + + + align:start position:0% +at most the trace of the fourth power +minus the top eigenvalue raised to the + + align:start position:0% +minus the top eigenvalue raised to the + + + align:start position:0% +minus the top eigenvalue raised to the +fourth power some of the other + + align:start position:0% +fourth power some of the other + + + align:start position:0% +fourth power some of the other +eigenvalue raised to the fourth power + + align:start position:0% +eigenvalue raised to the fourth power + + + align:start position:0% +eigenvalue raised to the fourth power +and for here we're using the force an + + align:start position:0% +and for here we're using the force an + + + align:start position:0% +and for here we're using the force an +even number okay so you have this over + + align:start position:0% +even number okay so you have this over + + + align:start position:0% +even number okay so you have this over +here so having a c4 hypothesis and also + + align:start position:0% +here so having a c4 hypothesis and also + + + align:start position:0% +here so having a c4 hypothesis and also +knowing what lambda one is allows you to + + align:start position:0% +knowing what lambda one is allows you to + + + align:start position:0% +knowing what lambda one is allows you to +control the other lambdas + + align:start position:0% + + + + align:start position:0% + +she lambda one cannot be greater than + + align:start position:0% +she lambda one cannot be greater than + + + align:start position:0% +she lambda one cannot be greater than +much greater than PN also comes out at + + align:start position:0% +much greater than PN also comes out at + + + align:start position:0% +much greater than PN also comes out at +the same calculation yep thank you yeah + + align:start position:0% +the same calculation yep thank you yeah + + + align:start position:0% +the same calculation yep thank you yeah +so there's a correction so lambda one is + + align:start position:0% +so there's a correction so lambda one is + + + align:start position:0% +so there's a correction so lambda one is +so so in other words the little always + + align:start position:0% +so so in other words the little always + + + align:start position:0% +so so in other words the little always +always respect you the constant density + + align:start position:0% + + + + align:start position:0% + +okay yep okay so the question is in I + + align:start position:0% +okay yep okay so the question is in I + + + align:start position:0% +okay yep okay so the question is in I +can value implies C for said something + + align:start position:0% +can value implies C for said something + + + align:start position:0% +can value implies C for said something +about the lower bound so I'm not saying + + align:start position:0% +about the lower bound so I'm not saying + + + align:start position:0% +about the lower bound so I'm not saying +that so as written over here what this + + align:start position:0% +that so as written over here what this + + + align:start position:0% +that so as written over here what this +is what we have proved I saw him but + + align:start position:0% +is what we have proved I saw him but + + + align:start position:0% +is what we have proved I saw him but +when you think about the pseudo + + align:start position:0% +when you think about the pseudo + + + align:start position:0% +when you think about the pseudo +randomness condition for C for it + + align:start position:0% +randomness condition for C for it + + + align:start position:0% +randomness condition for C for it +shouldn't be just that the number C for + + align:start position:0% +shouldn't be just that the number C for + + + align:start position:0% +shouldn't be just that the number C for +count is and most something should be + + align:start position:0% +count is and most something should be + + + align:start position:0% +count is and most something should be +that in close to that which would be + + align:start position:0% +that in close to that which would be + + + align:start position:0% +that in close to that which would be +implied by the c4 condition itself + + align:start position:0% +implied by the c4 condition itself + + + align:start position:0% +implied by the c4 condition itself +because we know always it is the case + + align:start position:0% +because we know always it is the case + + + align:start position:0% +because we know always it is the case +that the c-4 count is at least compare + + align:start position:0% +that the c-4 count is at least compare + + + align:start position:0% +that the c-4 count is at least compare +what it is compared to the random case + + align:start position:0% + + + + align:start position:0% + +one more thing I said was that lambda + + align:start position:0% +one more thing I said was that lambda + + + align:start position:0% +one more thing I said was that lambda +one you also know that it is at most P + + align:start position:0% +one you also know that it is at most P + + + align:start position:0% +one you also know that it is at most P +and plus n right because + + align:start position:0% + + + + align:start position:0% + +so this finishes the proof of the Chong + + align:start position:0% +so this finishes the proof of the Chong + + + align:start position:0% +so this finishes the proof of the Chong +Graham Wilson theorem on quasi random + + align:start position:0% +Graham Wilson theorem on quasi random + + + align:start position:0% +Graham Wilson theorem on quasi random +graphs and we stated all of these + + align:start position:0% +graphs and we stated all of these + + + align:start position:0% +graphs and we stated all of these +hypotheses and they're all equivalent to + + align:start position:0% +hypotheses and they're all equivalent to + + + align:start position:0% +hypotheses and they're all equivalent to +each other and I want to emphasize again + + align:start position:0% +each other and I want to emphasize again + + + align:start position:0% +each other and I want to emphasize again +the most surprising one is that c4 + + align:start position:0% +the most surprising one is that c4 + + + align:start position:0% +the most surprising one is that c4 +implies everything else they're fairly + + align:start position:0% +implies everything else they're fairly + + + align:start position:0% +implies everything else they're fairly +weak seeming condition seemingly weak + + align:start position:0% +weak seeming condition seemingly weak + + + align:start position:0% +weak seeming condition seemingly weak +condition this just having the correct + + align:start position:0% +condition this just having the correct + + + align:start position:0% +condition this just having the correct +number of copies of labeled C force is + + align:start position:0% +number of copies of labeled C force is + + + align:start position:0% +number of copies of labeled C force is +enough to guarantee all of these other + + align:start position:0% +enough to guarantee all of these other + + + align:start position:0% +enough to guarantee all of these other +much more complicated looking conditions + + align:start position:0% +much more complicated looking conditions + + + align:start position:0% +much more complicated looking conditions +and in particular just having the C for + + align:start position:0% +and in particular just having the C for + + + align:start position:0% +and in particular just having the C for +count correct implies that the counts of + + align:start position:0% +count correct implies that the counts of + + + align:start position:0% +count correct implies that the counts of +every other graph H is correct now one + + align:start position:0% +every other graph H is correct now one + + + align:start position:0% +every other graph H is correct now one +thing I want to stress is that the Chun + + align:start position:0% +thing I want to stress is that the Chun + + + align:start position:0% +thing I want to stress is that the Chun +Graham Wilson theorem it's really about + + align:start position:0% +Graham Wilson theorem it's really about + + + align:start position:0% +Graham Wilson theorem it's really about +dense graphs and by dense here I mean P + + align:start position:0% +dense graphs and by dense here I mean P + + + align:start position:0% +dense graphs and by dense here I mean P +constant of course the theorem as stated + + align:start position:0% +constant of course the theorem as stated + + + align:start position:0% +constant of course the theorem as stated +is true if you let P equals to zero so + + align:start position:0% +is true if you let P equals to zero so + + + align:start position:0% +is true if you let P equals to zero so +there I said P strictly between 0 and 1 + + align:start position:0% +there I said P strictly between 0 and 1 + + + align:start position:0% +there I said P strictly between 0 and 1 +but it's also ok if you let P equal to 0 + + align:start position:0% + + + + align:start position:0% + +you don't get such interesting theorems + + align:start position:0% +you don't get such interesting theorems + + + align:start position:0% +you don't get such interesting theorems +but but it is still true but for sparse + + align:start position:0% +but but it is still true but for sparse + + + align:start position:0% +but but it is still true but for sparse +graphs what you really want to care + + align:start position:0% +graphs what you really want to care + + + align:start position:0% +graphs what you really want to care +about is approximations at the correct + + align:start position:0% +about is approximations at the correct + + + align:start position:0% +about is approximations at the correct +order of magnitude so what I mean is + + align:start position:0% +order of magnitude so what I mean is + + + align:start position:0% +order of magnitude so what I mean is +that you can write down some sparse + + align:start position:0% +that you can write down some sparse + + + align:start position:0% +that you can write down some sparse +analogues for P going to 0 so P as a + + align:start position:0% +analogues for P going to 0 so P as a + + + align:start position:0% +analogues for P going to 0 so P as a +function of n going to 0 as n goes to + + align:start position:0% +function of n going to 0 as n goes to + + + align:start position:0% +function of n going to 0 as n goes to +infinity ok so let me just write down a + + align:start position:0% +infinity ok so let me just write down a + + + align:start position:0% +infinity ok so let me just write down a +couple of examples but I won't do all of + + align:start position:0% +couple of examples but I won't do all of + + + align:start position:0% +couple of examples but I won't do all of +them and you can imagine what they + + align:start position:0% +them and you can imagine what they + + + align:start position:0% +them and you can imagine what they +should look like so disk should say this + + align:start position:0% +should look like so disk should say this + + + align:start position:0% +should look like so disk should say this +quantity over here the discrepancy + + align:start position:0% +quantity over here the discrepancy + + + align:start position:0% +quantity over here the discrepancy +condition is + + align:start position:0% + + + + align:start position:0% + +not all of P M squared because P N + + align:start position:0% +not all of P M squared because P N + + + align:start position:0% +not all of P M squared because P N +squared is the edge density overall so + + align:start position:0% +squared is the edge density overall so + + + align:start position:0% +squared is the edge density overall so +that's the quantity you should compare + + align:start position:0% +that's the quantity you should compare + + + align:start position:0% +that's the quantity you should compare +against and not N squared if you're + + align:start position:0% +against and not N squared if you're + + + align:start position:0% +against and not N squared if you're +compare N squared you know you're + + align:start position:0% +compare N squared you know you're + + + align:start position:0% +compare N squared you know you're +cheating because N squared is much + + align:start position:0% +cheating because N squared is much + + + align:start position:0% +cheating because N squared is much +bigger than the actual edge density + + align:start position:0% +bigger than the actual edge density + + + align:start position:0% +bigger than the actual edge density +likewise the number of labeled copies of + + align:start position:0% +likewise the number of labeled copies of + + + align:start position:0% +likewise the number of labeled copies of +age yes I want to put the little ol 1 + + align:start position:0% +age yes I want to put the little ol 1 + + + align:start position:0% +age yes I want to put the little ol 1 +plus little in front right so instead of + + align:start position:0% +plus little in front right so instead of + + + align:start position:0% +plus little in front right so instead of +plus little ol end to the H at the end + + align:start position:0% + + + + align:start position:0% + +as you understand the difference there + + align:start position:0% +as you understand the difference there + + + align:start position:0% +as you understand the difference there +so for sparse this is the correct + + align:start position:0% +so for sparse this is the correct + + + align:start position:0% +so for sparse this is the correct +normalization that you should have when + + align:start position:0% +normalization that you should have when + + + align:start position:0% +normalization that you should have when +P is allowed to go to 0 as a function of + + align:start position:0% +P is allowed to go to 0 as a function of + + + align:start position:0% +P is allowed to go to 0 as a function of +N and you can write down all of these + + align:start position:0% +N and you can write down all of these + + + align:start position:0% +N and you can write down all of these +conditions right I'm not saying there's + + align:start position:0% +conditions right I'm not saying there's + + + align:start position:0% +conditions right I'm not saying there's +a theorem you can write down all these + + align:start position:0% +a theorem you can write down all these + + + align:start position:0% +a theorem you can write down all these +conditions and you can ask is there also + + align:start position:0% +conditions and you can ask is there also + + + align:start position:0% +conditions and you can ask is there also +some notion of equivalence I'm sorry are + + align:start position:0% +some notion of equivalence I'm sorry are + + + align:start position:0% +some notion of equivalence I'm sorry are +these corresponding conditions also + + align:start position:0% +these corresponding conditions also + + + align:start position:0% +these corresponding conditions also +equivalent to each other and the answer + + align:start position:0% +equivalent to each other and the answer + + + align:start position:0% +equivalent to each other and the answer +is emphatically no absolutely not so all + + align:start position:0% +is emphatically no absolutely not so all + + + align:start position:0% +is emphatically no absolutely not so all +of these equivalent tests fail for + + align:start position:0% +of these equivalent tests fail for + + + align:start position:0% +of these equivalent tests fail for +sparse some of them are still true in + + align:start position:0% +sparse some of them are still true in + + + align:start position:0% +sparse some of them are still true in +some of the easier ones that we did for + + align:start position:0% +some of the easier ones that we did for + + + align:start position:0% +some of the easier ones that we did for +example the two versions of discs are + + align:start position:0% +example the two versions of discs are + + + align:start position:0% +example the two versions of discs are +equivalent that's the okay and some of + + align:start position:0% +equivalent that's the okay and some of + + + align:start position:0% +equivalent that's the okay and some of +these calculations involving + + align:start position:0% +these calculations involving + + + align:start position:0% +these calculations involving +cauchy-schwarz or you know mostly still + + align:start position:0% +cauchy-schwarz or you know mostly still + + + align:start position:0% +cauchy-schwarz or you know mostly still +ok but the one that really fails is the + + align:start position:0% +ok but the one that really fails is the + + + align:start position:0% +ok but the one that really fails is the +counting lemma + + align:start position:0% + + + + align:start position:0% + +and let me explain why with an example + + align:start position:0% +and let me explain why with an example + + + align:start position:0% +and let me explain why with an example +so I want to give you an example of a + + align:start position:0% +so I want to give you an example of a + + + align:start position:0% +so I want to give you an example of a +graph which looks pseudo random in the + + align:start position:0% +graph which looks pseudo random in the + + + align:start position:0% +graph which looks pseudo random in the +sense of disk but has no C for let's say + + align:start position:0% +sense of disk but has no C for let's say + + + align:start position:0% +sense of disk but has no C for let's say +C 3 count also has no C for Campbell + + align:start position:0% +C 3 count also has no C for Campbell + + + align:start position:0% +C 3 count also has no C for Campbell +just Xu has no triangle as the Keene + + align:start position:0% +just Xu has no triangle as the Keene + + + align:start position:0% +just Xu has no triangle as the Keene +correct number of triangles alright so + + align:start position:0% +correct number of triangles alright so + + + align:start position:0% +correct number of triangles alright so +what's this example so let P be some + + align:start position:0% +what's this example so let P be some + + + align:start position:0% +what's this example so let P be some +number which is no off 1 over root n so + + align:start position:0% +number which is no off 1 over root n so + + + align:start position:0% +number which is no off 1 over root n so +some decaying quantity with N and let's + + align:start position:0% +some decaying quantity with N and let's + + + align:start position:0% +some decaying quantity with N and let's +consider GMP well how many triangles do + + align:start position:0% +consider GMP well how many triangles do + + + align:start position:0% +consider GMP well how many triangles do +we expect in GMP so let's think of + + align:start position:0% +we expect in GMP so let's think of + + + align:start position:0% +we expect in GMP so let's think of +Pierre just slightly below 1 over root n + + align:start position:0% +Pierre just slightly below 1 over root n + + + align:start position:0% +Pierre just slightly below 1 over root n +so the number of triangles in GMP in + + align:start position:0% +so the number of triangles in GMP in + + + align:start position:0% +so the number of triangles in GMP in +expectation so that's that's the + + align:start position:0% +expectation so that's that's the + + + align:start position:0% +expectation so that's that's the +expected number and you should expect + + align:start position:0% +expected number and you should expect + + + align:start position:0% +expected number and you should expect +the actual number to be roughly around + + align:start position:0% +the actual number to be roughly around + + + align:start position:0% +the actual number to be roughly around +that but on the other hand the number of + + align:start position:0% +that but on the other hand the number of + + + align:start position:0% +that but on the other hand the number of +edges it's also expected to be okay so + + align:start position:0% +edges it's also expected to be okay so + + + align:start position:0% +edges it's also expected to be okay so +this quantity here and you expect that + + align:start position:0% +this quantity here and you expect that + + + align:start position:0% +this quantity here and you expect that +the actual number of edges to be very + + align:start position:0% +the actual number of edges to be very + + + align:start position:0% +the actual number of edges to be very +close to it but P is chosen so that the + + align:start position:0% +close to it but P is chosen so that the + + + align:start position:0% +close to it but P is chosen so that the +number of triangles is significantly + + align:start position:0% +number of triangles is significantly + + + align:start position:0% +number of triangles is significantly +smaller than the number of edges so + + align:start position:0% +smaller than the number of edges so + + + align:start position:0% +smaller than the number of edges so +asymptotically smaller fewer copies of + + align:start position:0% +asymptotically smaller fewer copies of + + + align:start position:0% +asymptotically smaller fewer copies of +triangles than edges so what we can do + + align:start position:0% +triangles than edges so what we can do + + + align:start position:0% +triangles than edges so what we can do +now is remove + + align:start position:0% +now is remove + + + align:start position:0% +now is remove +an edge from each copy of a triangle in + + align:start position:0% +an edge from each copy of a triangle in + + + align:start position:0% +an edge from each copy of a triangle in +this GNP we removed a tiny fraction of + + align:start position:0% +this GNP we removed a tiny fraction of + + + align:start position:0% +this GNP we removed a tiny fraction of +edges because the number of triangles is + + align:start position:0% +edges because the number of triangles is + + + align:start position:0% +edges because the number of triangles is +much less than number of edges we remove + + align:start position:0% +much less than number of edges we remove + + + align:start position:0% +much less than number of edges we remove +the tiny fraction of edges and as a + + align:start position:0% +the tiny fraction of edges and as a + + + align:start position:0% +the tiny fraction of edges and as a +result we do not change the discrepancy + + align:start position:0% +result we do not change the discrepancy + + + align:start position:0% +result we do not change the discrepancy +condition up to a small there error so + + align:start position:0% +condition up to a small there error so + + + align:start position:0% +condition up to a small there error so +the discrepancy condition still holds + + align:start position:0% + + + + align:start position:0% + +however the graph has normal triangles + + align:start position:0% + + + + align:start position:0% + +so you have this pseudo random graph in + + align:start position:0% +so you have this pseudo random graph in + + + align:start position:0% +so you have this pseudo random graph in +one sense namely of having discrepancy + + align:start position:0% +one sense namely of having discrepancy + + + align:start position:0% +one sense namely of having discrepancy +but fails to be pseudo random in a + + align:start position:0% +but fails to be pseudo random in a + + + align:start position:0% +but fails to be pseudo random in a +different sense namely has no triangles + + align:start position:0% +different sense namely has no triangles + + + align:start position:0% +different sense namely has no triangles +yep we're question to the condition c4 + + align:start position:0% +yep we're question to the condition c4 + + + align:start position:0% +yep we're question to the condition c4 +and coda we still hold here basically + + align:start position:0% +and coda we still hold here basically + + + align:start position:0% +and coda we still hold here basically +downstream is okay but upstream is not + + align:start position:0% +downstream is okay but upstream is not + + + align:start position:0% +downstream is okay but upstream is not +okay so you can go from Seaforth code + + align:start position:0% +okay so you can go from Seaforth code + + + align:start position:0% +okay so you can go from Seaforth code +agree to disk but you can't go upward + + align:start position:0% +agree to disk but you can't go upward + + + align:start position:0% +agree to disk but you can't go upward +and understanding how to rectify the + + align:start position:0% +and understanding how to rectify the + + + align:start position:0% +and understanding how to rectify the +situation may perhaps adding additional + + align:start position:0% +situation may perhaps adding additional + + + align:start position:0% +situation may perhaps adding additional +hypotheses to make this true so that you + + align:start position:0% +hypotheses to make this true so that you + + + align:start position:0% +hypotheses to make this true so that you +could have counting llamas for triangles + + align:start position:0% +could have counting llamas for triangles + + + align:start position:0% +could have counting llamas for triangles +and other graphs in sparser graphs + + align:start position:0% +and other graphs in sparser graphs + + + align:start position:0% +and other graphs in sparser graphs +that's an important topic and this is + + align:start position:0% +that's an important topic and this is + + + align:start position:0% +that's an important topic and this is +something that we'll discuss at greater + + align:start position:0% +something that we'll discuss at greater + + + align:start position:0% +something that we'll discuss at greater +length in non-black not next lecture but + + align:start position:0% +length in non-black not next lecture but + + + align:start position:0% +length in non-black not next lecture but +the one after that and this is in fact + + align:start position:0% +the one after that and this is in fact + + + align:start position:0% +the one after that and this is in fact +related to the green-tailed theorem + + align:start position:0% +related to the green-tailed theorem + + + align:start position:0% +related to the green-tailed theorem +which allows you to prove similarities + + align:start position:0% +which allows you to prove similarities + + + align:start position:0% +which allows you to prove similarities +term among the primes the primes contain + + align:start position:0% +term among the primes the primes contain + + + align:start position:0% +term among the primes the primes contain +arbitrarily long arithmetic progressions + + align:start position:0% +arbitrarily long arithmetic progressions + + + align:start position:0% +arbitrarily long arithmetic progressions +because the primes are also a sparse set + + align:start position:0% +because the primes are also a sparse set + + + align:start position:0% +because the primes are also a sparse set +so as density going to zero density that + + align:start position:0% +so as density going to zero density that + + + align:start position:0% +so as density going to zero density that +came like 1 over log and according to + + align:start position:0% +came like 1 over log and according to + + + align:start position:0% +came like 1 over log and according to +prime number theorem but you want to do + + align:start position:0% +prime number theorem but you want to do + + + align:start position:0% +prime number theorem but you want to do +regularity method so you have to face + + align:start position:0% +regularity method so you have to face + + + align:start position:0% +regularity method so you have to face +this kind of issues so just okay so + + align:start position:0% +this kind of issues so just okay so + + + align:start position:0% +this kind of issues so just okay so +we'll discuss that more length in a + + align:start position:0% +we'll discuss that more length in a + + + align:start position:0% +we'll discuss that more length in a +couple of lectures but for now just a + + align:start position:0% +couple of lectures but for now just a + + + align:start position:0% +couple of lectures but for now just a +warning that everything here it's really + + align:start position:0% +warning that everything here it's really + + + align:start position:0% +warning that everything here it's really +about dense graphs the next thing I want + + align:start position:0% +about dense graphs the next thing I want + + + align:start position:0% +about dense graphs the next thing I want +to discuss is an elaboration of what + + align:start position:0% +to discuss is an elaboration of what + + + align:start position:0% +to discuss is an elaboration of what +happens to these eigenvalue conditions + + align:start position:0% +happens to these eigenvalue conditions + + + align:start position:0% +happens to these eigenvalue conditions +[Applause] + + align:start position:0% + + + + align:start position:0% + +so for dense graphs in some sense + + align:start position:0% +so for dense graphs in some sense + + + align:start position:0% +so for dense graphs in some sense +everything is very clear from this + + align:start position:0% +everything is very clear from this + + + align:start position:0% +everything is very clear from this +theorem like once you have this theorem + + align:start position:0% +theorem like once you have this theorem + + + align:start position:0% +theorem like once you have this theorem +they're all equivalent you can go back + + align:start position:0% +they're all equivalent you can go back + + + align:start position:0% +they're all equivalent you can go back +and forth and you know you lose a little + + align:start position:0% +and forth and you know you lose a little + + + align:start position:0% +and forth and you know you lose a little +bit like epsilon here and there but + + align:start position:0% +bit like epsilon here and there but + + + align:start position:0% +bit like epsilon here and there but +everything is more or less the same but + + align:start position:0% +everything is more or less the same but + + + align:start position:0% +everything is more or less the same but +if you go to sparser world then you + + align:start position:0% +if you go to sparser world then you + + + align:start position:0% +if you go to sparser world then you +really need to be much more careful we + + align:start position:0% +really need to be much more careful we + + + align:start position:0% +really need to be much more careful we +need to think about other tools and so + + align:start position:0% +need to think about other tools and so + + + align:start position:0% +need to think about other tools and so +the remainder of today I want to just + + align:start position:0% +the remainder of today I want to just + + + align:start position:0% +the remainder of today I want to just +discuss one pretty simple but powerful + + align:start position:0% +discuss one pretty simple but powerful + + + align:start position:0% +discuss one pretty simple but powerful +tool relating I can values on one hand + + align:start position:0% +tool relating I can values on one hand + + + align:start position:0% +tool relating I can values on one hand +and a discrepancy condition on the other + + align:start position:0% +and a discrepancy condition on the other + + + align:start position:0% +and a discrepancy condition on the other +hand right so you can go from eigenvalue + + align:start position:0% +hand right so you can go from eigenvalue + + + align:start position:0% +hand right so you can go from eigenvalue +to discrepancy by going down this chain + + align:start position:0% +to discrepancy by going down this chain + + + align:start position:0% +to discrepancy by going down this chain +but it's actually there's a much quicker + + align:start position:0% +but it's actually there's a much quicker + + + align:start position:0% +but it's actually there's a much quicker +route and this is known as the expander + + align:start position:0% +route and this is known as the expander + + + align:start position:0% +route and this is known as the expander +mixing them for simplicity and really + + align:start position:0% +mixing them for simplicity and really + + + align:start position:0% +mixing them for simplicity and really +will make our life much simpler we're + + align:start position:0% +will make our life much simpler we're + + + align:start position:0% +will make our life much simpler we're +only going to consider T regular graphs + + align:start position:0% +only going to consider T regular graphs + + + align:start position:0% +only going to consider T regular graphs +here T regular means every vertex s + + align:start position:0% +here T regular means every vertex s + + + align:start position:0% +here T regular means every vertex s +degree T same word but different meaning + + align:start position:0% +degree T same word but different meaning + + + align:start position:0% +degree T same word but different meaning +from epsilon regular and unfortunately + + align:start position:0% +from epsilon regular and unfortunately + + + align:start position:0% +from epsilon regular and unfortunately +that's just the way this so T regular + + align:start position:0% +that's just the way this so T regular + + + align:start position:0% +that's just the way this so T regular +and we're going to have n vertices and + + align:start position:0% +and we're going to have n vertices and + + + align:start position:0% +and we're going to have n vertices and +the adjacency matrix has eigenvalues + + align:start position:0% +the adjacency matrix has eigenvalues + + + align:start position:0% +the adjacency matrix has eigenvalues +lambda 1 lambda 2 and so on arranged in + + align:start position:0% +lambda 1 lambda 2 and so on arranged in + + + align:start position:0% +lambda 1 lambda 2 and so on arranged in +decreasing order let me write lambda as + + align:start position:0% +decreasing order let me write lambda as + + + align:start position:0% +decreasing order let me write lambda as +the maximum in absolute value of the + + align:start position:0% +the maximum in absolute value of the + + + align:start position:0% +the maximum in absolute value of the +eigenvalues except for the top one in + + align:start position:0% +eigenvalues except for the top one in + + + align:start position:0% +eigenvalues except for the top one in +particular this is either the absolute + + align:start position:0% +particular this is either the absolute + + + align:start position:0% +particular this is either the absolute +value of the second one or the last one + + align:start position:0% +value of the second one or the last one + + + align:start position:0% +value of the second one or the last one +as I mentioned earlier at the top + + align:start position:0% +as I mentioned earlier at the top + + + align:start position:0% +as I mentioned earlier at the top +eigenvalue is necessarily deep because + + align:start position:0% +eigenvalue is necessarily deep because + + + align:start position:0% +eigenvalue is necessarily deep because +you have all ones vector as an + + align:start position:0% +you have all ones vector as an + + + align:start position:0% +you have all ones vector as an +eigenvector so the expander mixing lemma + + align:start position:0% +eigenvector so the expander mixing lemma + + + align:start position:0% +eigenvector so the expander mixing lemma +says that if I look at to vertex subsets + + align:start position:0% + + + + align:start position:0% + +the number of edges between them + + align:start position:0% +the number of edges between them + + + align:start position:0% +the number of edges between them +compared to what you would expect in a + + align:start position:0% +compared to what you would expect in a + + + align:start position:0% +compared to what you would expect in a +random case so just like in a disk + + align:start position:0% +random case so just like in a disk + + + align:start position:0% +random case so just like in a disk +setting but here the correct density I + + align:start position:0% +setting but here the correct density I + + + align:start position:0% +setting but here the correct density I +should put is d over N this quantity is + + align:start position:0% +should put is d over N this quantity is + + + align:start position:0% +should put is d over N this quantity is +upper bounded by lambda times the root + + align:start position:0% +upper bounded by lambda times the root + + + align:start position:0% +upper bounded by lambda times the root +of the product of x and y so in + + align:start position:0% +of the product of x and y so in + + + align:start position:0% +of the product of x and y so in +particular if this lambda so everything + + align:start position:0% +particular if this lambda so everything + + + align:start position:0% +particular if this lambda so everything +except the top eigenvalue is small then + + align:start position:0% +except the top eigenvalue is small then + + + align:start position:0% +except the top eigenvalue is small then +this discrepancy should be small and you + + align:start position:0% +this discrepancy should be small and you + + + align:start position:0% +this discrepancy should be small and you +can verify with what we did that it's + + align:start position:0% +can verify with what we did that it's + + + align:start position:0% +can verify with what we did that it's +consistent what we put what we just did + + align:start position:0% +consistent what we put what we just did + + + align:start position:0% +consistent what we put what we just did +all right + + align:start position:0% +all right + + + align:start position:0% +all right +so let's prove the expander mixing lemma + + align:start position:0% +so let's prove the expander mixing lemma + + + align:start position:0% +so let's prove the expander mixing lemma +which is pretty simple given what we've + + align:start position:0% +which is pretty simple given what we've + + + align:start position:0% +which is pretty simple given what we've +discussed so far + + align:start position:0% +discussed so far + + + align:start position:0% +discussed so far +relating so there was this spectral + + align:start position:0% +relating so there was this spectral + + + align:start position:0% +relating so there was this spectral +characterization up there of the top I + + align:start position:0% +characterization up there of the top I + + + align:start position:0% +characterization up there of the top I +can value so we can let J be B or once + + align:start position:0% +can value so we can let J be B or once + + + align:start position:0% +can value so we can let J be B or once +matrix let J be the old ones matrix and + + align:start position:0% +matrix let J be the old ones matrix and + + + align:start position:0% +matrix let J be the old ones matrix and +we know that the all one's vector is an + + align:start position:0% +we know that the all one's vector is an + + + align:start position:0% +we know that the all one's vector is an +eigenvector of the adjacency matrix of G + + align:start position:0% +eigenvector of the adjacency matrix of G + + + align:start position:0% +eigenvector of the adjacency matrix of G +with eigen value D so the eigen + + align:start position:0% +with eigen value D so the eigen + + + align:start position:0% +with eigen value D so the eigen +decomposition of J is also the ovince + + align:start position:0% +decomposition of J is also the ovince + + + align:start position:0% +decomposition of J is also the ovince +vector and it's complement so we now see + + align:start position:0% +vector and it's complement so we now see + + + align:start position:0% +vector and it's complement so we now see +that a sub G minus T over and J has the + + align:start position:0% +that a sub G minus T over and J has the + + + align:start position:0% +that a sub G minus T over and J has the +same + + align:start position:0% + + + + align:start position:0% + +I can vectors as AG so you can choose + + align:start position:0% +I can vectors as AG so you can choose + + + align:start position:0% +I can vectors as AG so you can choose +the eigenvectors for that it's the same + + align:start position:0% +the eigenvectors for that it's the same + + + align:start position:0% +the eigenvectors for that it's the same +set of eigenvectors of course we + + align:start position:0% +set of eigenvectors of course we + + + align:start position:0% +set of eigenvectors of course we +consider this quantity here because this + + align:start position:0% +consider this quantity here because this + + + align:start position:0% +consider this quantity here because this +is exactly the quality that comes up in + + align:start position:0% +is exactly the quality that comes up in + + + align:start position:0% +is exactly the quality that comes up in +this expression once we hit it by + + align:start position:0% +this expression once we hit it by + + + align:start position:0% +this expression once we hit it by +characteristic vectors of subsets from + + align:start position:0% +characteristic vectors of subsets from + + + align:start position:0% +characteristic vectors of subsets from +left and right okay so so what are the + + align:start position:0% +left and right okay so so what are the + + + align:start position:0% +left and right okay so so what are the +eigenvalues okay so the eigenvalues so a + + align:start position:0% +eigenvalues okay so the eigenvalues so a + + + align:start position:0% +eigenvalues okay so the eigenvalues so a +previously had eigenvalues blend the 1 + + align:start position:0% +previously had eigenvalues blend the 1 + + + align:start position:0% +previously had eigenvalues blend the 1 +through lambda and but now the top one + + align:start position:0% +through lambda and but now the top one + + + align:start position:0% +through lambda and but now the top one +gets chopped down to 0 so you can check + + align:start position:0% +gets chopped down to 0 so you can check + + + align:start position:0% +gets chopped down to 0 so you can check +this explicitly so you can check this + + align:start position:0% +this explicitly so you can check this + + + align:start position:0% +this explicitly so you can check this +explicitly by checking that if you take + + align:start position:0% +explicitly by checking that if you take + + + align:start position:0% +explicitly by checking that if you take +this matrix multiplied by the or ones + + align:start position:0% +this matrix multiplied by the or ones + + + align:start position:0% +this matrix multiplied by the or ones +vector you get 0 and if you have an + + align:start position:0% +vector you get 0 and if you have an + + + align:start position:0% +vector you get 0 and if you have an +eigenvector eigenvalue pair then hitting + + align:start position:0% +eigenvector eigenvalue pair then hitting + + + align:start position:0% +eigenvector eigenvalue pair then hitting +this by any of the other ones gets you + + align:start position:0% +this by any of the other ones gets you + + + align:start position:0% +this by any of the other ones gets you +the same as in a because now the + + align:start position:0% +the same as in a because now the + + + align:start position:0% +the same as in a because now the +condition or the other eigen vectors are + + align:start position:0% +condition or the other eigen vectors are + + + align:start position:0% +condition or the other eigen vectors are +orthogonal to the or once vector all + + align:start position:0% +orthogonal to the or once vector all + + + align:start position:0% +orthogonal to the or once vector all +right so now we apply the quran fisher + + align:start position:0% +right so now we apply the quran fisher + + + align:start position:0% +right so now we apply the quran fisher +criteria which tells us that the number + + align:start position:0% +criteria which tells us that the number + + + align:start position:0% +criteria which tells us that the number +in this discrepancy quantity + + align:start position:0% + + + + align:start position:0% + +which we can write in terms of this + + align:start position:0% +which we can write in terms of this + + + align:start position:0% +which we can write in terms of this +matrix it is upper bounded by the + + align:start position:0% +matrix it is upper bounded by the + + + align:start position:0% +matrix it is upper bounded by the +product of the lengths of these two + + align:start position:0% +product of the lengths of these two + + + align:start position:0% +product of the lengths of these two +vectors x and y multiplied by the + + align:start position:0% +vectors x and y multiplied by the + + + align:start position:0% +vectors x and y multiplied by the +spectral norm not quite using the + + align:start position:0% +spectral norm not quite using the + + + align:start position:0% +spectral norm not quite using the +version up there but I'm using the + + align:start position:0% +version up there but I'm using the + + + align:start position:0% +version up there but I'm using the +spectral norm version which we discussed + + align:start position:0% +spectral norm version which we discussed + + + align:start position:0% +spectral norm version which we discussed +last time it's essentially one up there + + align:start position:0% +last time it's essentially one up there + + + align:start position:0% +last time it's essentially one up there +but you allow not just single x / x and + + align:start position:0% +but you allow not just single x / x and + + + align:start position:0% +but you allow not just single x / x and +y and that corresponds to the largest + + align:start position:0% +y and that corresponds to the largest + + + align:start position:0% +y and that corresponds to the largest +eigen value in absolute value which we + + align:start position:0% +eigen value in absolute value which we + + + align:start position:0% +eigen value in absolute value which we +see that at most lambda so it's the most + + align:start position:0% +see that at most lambda so it's the most + + + align:start position:0% +see that at most lambda so it's the most +lambda times size of x size of y okay + + align:start position:0% +lambda times size of x size of y okay + + + align:start position:0% +lambda times size of x size of y okay +nothing is the proof of the expander + + align:start position:0% +nothing is the proof of the expander + + + align:start position:0% +nothing is the proof of the expander +mixing lemma so the moral here is that + + align:start position:0% +mixing lemma so the moral here is that + + + align:start position:0% +mixing lemma so the moral here is that +just like what we saw earlier when the + + align:start position:0% +just like what we saw earlier when the + + + align:start position:0% +just like what we saw earlier when the +in the tense cadiz but for any + + align:start position:0% +in the tense cadiz but for any + + + align:start position:0% +in the tense cadiz but for any +parameters so here there's no it's a + + align:start position:0% +parameters so here there's no it's a + + + align:start position:0% +parameters so here there's no it's a +very clean statement you can even have + + align:start position:0% +very clean statement you can even have + + + align:start position:0% +very clean statement you can even have +found the degree graphs he could be + + align:start position:0% +found the degree graphs he could be + + + align:start position:0% +found the degree graphs he could be +constant if lambda is small compared to + + align:start position:0% +constant if lambda is small compared to + + + align:start position:0% +constant if lambda is small compared to +D then you have this discrepancy + + align:start position:0% +D then you have this discrepancy + + + align:start position:0% +D then you have this discrepancy +condition and the reason why this is + + align:start position:0% +condition and the reason why this is + + + align:start position:0% +condition and the reason why this is +called an expander mixing lemma is that + + align:start position:0% +called an expander mixing lemma is that + + + align:start position:0% +called an expander mixing lemma is that +there's this notion of expanders which + + align:start position:0% +there's this notion of expanders which + + + align:start position:0% +there's this notion of expanders which +is not quite the same but very + + align:start position:0% +is not quite the same but very + + + align:start position:0% +is not quite the same but very +intimately related to pseudo-random + + align:start position:0% +intimately related to pseudo-random + + + align:start position:0% +intimately related to pseudo-random +grass so one property of pseudo-random + + align:start position:0% +grass so one property of pseudo-random + + + align:start position:0% +grass so one property of pseudo-random +graphs that is quite useful in + + align:start position:0% +graphs that is quite useful in + + + align:start position:0% +graphs that is quite useful in +particular in computer science is that + + align:start position:0% +particular in computer science is that + + + align:start position:0% +particular in computer science is that +if you take a small subset of vertices + + align:start position:0% +if you take a small subset of vertices + + + align:start position:0% +if you take a small subset of vertices +it has lots of neighbors so the graph is + + align:start position:0% +it has lots of neighbors so the graph is + + + align:start position:0% +it has lots of neighbors so the graph is +now somehow in a cluster into a few + + align:start position:0% +now somehow in a cluster into a few + + + align:start position:0% +now somehow in a cluster into a few +local pieces so there's lots of + + align:start position:0% +local pieces so there's lots of + + + align:start position:0% +local pieces so there's lots of +expansion + + align:start position:0% +expansion + + + align:start position:0% +expansion +and and and that's something that you + + align:start position:0% +and and and that's something that you + + + align:start position:0% +and and and that's something that you +can guarantee using in the expand your + + align:start position:0% +can guarantee using in the expand your + + + align:start position:0% +can guarantee using in the expand your +mixing lemma that you have lots of you + + align:start position:0% +mixing lemma that you have lots of you + + + align:start position:0% +mixing lemma that you have lots of you +take a small set of vertices you can + + align:start position:0% +take a small set of vertices you can + + + align:start position:0% +take a small set of vertices you can +expand outward so graphs with that + + align:start position:0% +expand outward so graphs with that + + + align:start position:0% +expand outward so graphs with that +specific property taking small subset of + + align:start position:0% +specific property taking small subset of + + + align:start position:0% +specific property taking small subset of +vertices always gets you loss of + + align:start position:0% +vertices always gets you loss of + + + align:start position:0% +vertices always gets you loss of +neighbors are called expand their graphs + + align:start position:0% +neighbors are called expand their graphs + + + align:start position:0% +neighbors are called expand their graphs +and these graphs play important role in + + align:start position:0% +and these graphs play important role in + + + align:start position:0% +and these graphs play important role in +in particular in computer science in + + align:start position:0% +in particular in computer science in + + + align:start position:0% +in particular in computer science in +designing algorithms improving + + align:start position:0% +designing algorithms improving + + + align:start position:0% +designing algorithms improving +complexity results and so on but also + + align:start position:0% +complexity results and so on but also + + + align:start position:0% +complexity results and so on but also +play important roles in graph theory and + + align:start position:0% +play important roles in graph theory and + + + align:start position:0% +play important roles in graph theory and +combinatorics well next time we'll + + align:start position:0% +combinatorics well next time we'll + + + align:start position:0% +combinatorics well next time we'll +address a few questions which are along + + align:start position:0% +address a few questions which are along + + + align:start position:0% +address a few questions which are along +the lines of one how small can lambda B + + align:start position:0% +the lines of one how small can lambda B + + + align:start position:0% +the lines of one how small can lambda B +as a function of T right so here it's as + + align:start position:0% +as a function of T right so here it's as + + + align:start position:0% +as a function of T right so here it's as +if lambda is small compared to D then + + align:start position:0% +if lambda is small compared to D then + + + align:start position:0% +if lambda is small compared to D then +you have this discrepancy but can it be + + align:start position:0% +you have this discrepancy but can it be + + + align:start position:0% +you have this discrepancy but can it be +you know if D is let's say am Union how + + align:start position:0% +you know if D is let's say am Union how + + + align:start position:0% +you know if D is let's say am Union how +small can lambda be that's one question + + align:start position:0% +small can lambda be that's one question + + + align:start position:0% +small can lambda be that's one question +another question is is considering you + + align:start position:0% +another question is is considering you + + + align:start position:0% +another question is is considering you +know everything that we've said so far + + align:start position:0% +know everything that we've said so far + + + align:start position:0% +know everything that we've said so far +what can we say about let's say that the + + align:start position:0% +what can we say about let's say that the + + + align:start position:0% +what can we say about let's say that the +relationship between some of these + + align:start position:0% +relationship between some of these + + + align:start position:0% +relationship between some of these +conditions for sparse graphs but that + + align:start position:0% +conditions for sparse graphs but that + + + align:start position:0% +conditions for sparse graphs but that +are somewhat special for example KD + + align:start position:0% +are somewhat special for example KD + + + align:start position:0% +are somewhat special for example KD +graphs or vertex-transitive graphs and + + align:start position:0% +graphs or vertex-transitive graphs and + + + align:start position:0% +graphs or vertex-transitive graphs and +turns out some of these relations are + + align:start position:0% +turns out some of these relations are + + + align:start position:0% +turns out some of these relations are +also equivalent to each other \ No newline at end of file diff --git a/UesUBkX9HIQ.txt b/UesUBkX9HIQ.txt new file mode 100644 index 0000000000000000000000000000000000000000..3854cb524397322e9b0d10260e0a185d984e6cf6 --- /dev/null +++ b/UesUBkX9HIQ.txt @@ -0,0 +1,1979 @@ +The following content is +provided by MIT OpenCourseWare + +under a Creative Commons +license. + +Additional information about +our license and MIT + +OpenCourseWare in general is +available at ocw.mit.edu. + +At the end of last hour, +we had just gotten to the point + +of having developed the +molecular orbital energy level + +diagram for the BH three +molecule, this trigonal planar + +entity. +And I had not had time last + +hour to show you what these +molecular orbitals look like in + +their calculated form. +And so, I am going to start off + +today by doing that, +and then will proceed to answer + +a quadrangle of questions that +we can attack regarding diatomic + +molecules using molecular +orbital theory. + +Remember that the BH three +MO problem is a seven + +orbital problem. +And so, we will go through and + +just look at these seven +molecular orbitals in ascending + +energy from the lowest energy on +up. + +This one is the lowest energy +molecular orbital for BH three + +as calculated using a +modern quantum chemical package. + +And what you can see is that +since we are indicating the + +phase of the wave function by +color, there is only one phase + +to be seen. +This, of course, + +is a characteristic property of +an s orbital. + +Remember that? +And what we have here, + +at the center of the molecule, +is the 2s orbital on boron. + +And in this molecular orbital +theory, effectively what is + +happening is that 2s orbital on +boron is reaching out and + +simultaneously overlapping with +the three 1s orbitals on each of + +the hydrogens. +And the way that we have + +orthogonalized it and normalized +it amounts to a single molecular + +orbital that can, +if you will, + +house a pair of electrons in +this orbital that is + +simultaneously bonding between +boron and the three hydrogens. + +You have one electron pair in +here. + +Two of the six electrons in the +valance shell of this molecule + +are in this lowest lying, +most tightly held, + +most electronegative molecular +orbital. + +Let's look now at the next one. + +You should be thinking in your +mind just what was the next + +highest lying orbital that we +had, and you will realize that + +this is an orbital formed from +one of the boron p orbitals and + +a linear combination of two of +the hydrogen wave functions. + +And let's see if you can +recognize it based on what we + +did last time. +Maybe I can reorient it to help + +in that regard. +Here is a molecular orbital + +that can house a pair of +electrons, one spin-up and one + +spin-down, and that is +simultaneously bonding from that + +boron to this hydrogen, +up here. + +And then there is a nodal +surface, here, + +that is coincident with the +nodal surfaces of the boron 2px + +orbital, using the same +coordinate system that we were + +using last time. +And so, the wave function + +changes sign as you pass through +the boron. + +And then the opposite phase +lobe of the boron 2px orbital is + +able to overlap with these two +hydrogens, here. + +If you will remember, +when I wrote down the + +normalization constants for this +molecular orbital, + +we had double the coefficient +on the hydrogen up here as + +compared with the two hydrogens +down here. + +And they were opposite in sign. +And that leads to a really nice + +overlap, as you can see here. +This is BH bonding here, + +and BH bonding, +down here. + +And it involves that boron 2px +orbital. + +One way you can think about +this molecular orbital theory is + +that this 2px orbital on the +central atom is reaching out + +with its intrinsic plus-minus +phase combination that is + +intrinsic to a 2px orbital +simultaneously reaching out and + +bonding with all three hydrogens +in the only way that it can, + +being a 2px orbital. +And so, we created that linear + +combination with that idea in +mind. + +And then, if we go up one more +in energy, strike that. + +Not one up more in energy, +but to the other orbital in the + +molecule that is at the same +energy. + +What we will find is that we +are involving, + +now, the 2py orbital. +And it will reach out and + +interact with hydrogens in the +only way it can, + +given its intrinsic nodal +properties as a 2py orbital. + +Remember that a 2py orbital has +the x,z-plane as a nodal + +surface. +And there is a hydrogen up here + +on that x,z-plane, +namely the one that lies on the + +plus x-axis. +And because it lies on the + +intrinsic nodal surface of this +2py orbital, it can contribute + +nothing to this molecular +orbital. + +All we are seeing up here at +the top is an arbitrarily sized + +sphere, just to show the +location of that nucleus, + +the hydrogen nucleus that is on +the plus x-axis. + +And then here, +what you see is the 2py orbital + +oriented along y and overlapping +simultaneously with a plus 1s + +wave function here and minus 1s +wave function here so that you + +see a beautiful bonding +molecular orbital that is at the + +same energy at the one we just +looked at. + +And so, as you step up in +energy, looking at the energy + +level diagram for BH three +from last time, + +that is what you see. +We have now six electrons in + +the molecule, +two in this orbital and two + +each in the two orbitals we just +looked at that provide the three + +BH bonds that we represent in +the valance bond theory as + +electron pair bonds. +But this is a totally different + +way of looking at the electronic +structure that is very appearing + +because it just takes advantage +of the atomic orbital properties + +that you would calculate for +your central atom. + +Now, let's go up one more. +The very next one, + +I will skip showing to you for +purposes of saving time, + +here, but you know that the +next orbital up is simply the + +2pz orbital on the boron, +which is our lowest unoccupied + +molecular orbital, +as well as being an atomic + +orbital in this system and +responsible for the Lewis acid + +characteristics of this species. +And one up above that, + +one higher in energy than the +LUMO is the orbital that I did + +show you last time, +the out-of-phase combination of + +the boron 2s with the three +hydrogens all with the same + +sign. +It is sort of a round nodal + +surface intersection each of the +BH bonds. + +And then, finally, +orbitals number six and seven + +are the antibonding counterparts +to the ones that I just showed + +you involving boron's 2px and +2py wave functions. + +Here is what these look like. +And this one, + +you will see, +involves the 2px orbital. + +Here is our x-axis pointing up. +And the blue lobe of 2px, + +the positive lobe here, +as you can see, + +is squished out and down. +These pictures can be a little + +bit more complicated than what +we are used to looking at from + +just sketching it out on the +board or the qualitative + +pictures that you sometimes see +in your textbook. + +But what we do find here that +is the important feature is that + +as we go from the 1s +contribution on this hydrogen + +over here to the positive lobe +of 2px we are going through a + +nodal surface. +And that is antibonding in + +character. +And you can see that this + +deformation of this lobe of the +p orbital, of course, + +looks like a high energy type +of phenomena. + +And indeed it is. +This is one of the two highest + +energy orbitals in the energy +level diagram for the BH three + +molecule. +And then, similarly, + +here is the other lobe of the +2px orbital, the minus lobe. + +And, as you try to go from it +to the adjacent hydrogens, + +remember, in the bonding one we +were allowing this to overlap + +with the same sign on the +hydrogens. + +Now we have the opposite sign +on the hydrogens, + +so that we have a beautiful +antibonding node indicated here + +and here between the minus phase +lobe of 2px and the adjacent + +hydrogens. +So, this antibonding orbital + +has lots of internuclear nodes, +nodes that appear between + +nuclei and indicate that we are +not getting overlapped and + +bonding, but rather we are +getting a high frequency orbital + +that is likewise high in energy. +Finally, I will show you the + +counterpart to this one, +that involves 2py. + +It is a little easier to +understand from inspecting it. + +And it also evinces the +internuclear nodes that you + +would expect for an antibonding +molecular orbital. + +And I am orienting it so that +you will be able to understand + +it with reference to our +coordinate system as introduced + +last time. +And so, you have the boron and + +the hydrogen along x, +up here. + +Here is our 2py. +It is sort of bending away from + +these two hydrogens whose wave +functions have opposite sign to + +the lobes that are directed into +their vicinity. + +You can see that we have here a +nodal surface between boron and + +this hydrogen wherein the +bonding counterpart that we + +looked at had the same sign and +a nice bond. + +And then over here, +once again, the mirror image. + +So, this is one of our final +orbitals in looking at the BH + +three energy level +diagram. + +It is the case that if you +start to put electrons into + +antibonding orbitals, +they will cancel the bonding + +properties of the bonding +counterparts. + +And we will explore that in +quite a bit more detail here + +shortly. +Let me leave that up there for + +now and tell you what quadrangle +of problems it is that I hope to + +answer for you today using more +MO theory ideas. + +First of these will be why He +two is so stable? + +And so, today's lecture is +predominantly devoted to + +diatomic molecules. +And He two will be the + +first of these. +Let's make this unstable. + +Let's do stable here in just a +moment, but first let's say, + +next, why does O two +have unpaired electrons? + +Certainly, if we draw the +valance bond picture for O two, + +like that, +it does not give us any + +indication that this diatomic +molecule would have unpaired + +electrons. +And so, we are going to see how + +MO theory can shed some light on +this issue. + +And then, the final two +questions that I will fold into + +one line here given the way I am +using up space on this board is, + +why is N two so stable +-- + +-- and CO poison? + +MO theory can shed very clear +light on all of these questions. + +And so, that is what we will +work on for the rest of the + +hour. +In MO theory, + +there are a couple things you +should keep in mind when trying + +to grasp all the subtleties of a +given energy level diagram with + +which you may be confronted in +your textbook or on an exam or + +just through reading papers in +the Journal of the American + +Chemical Society, +wherever you may find these. + +You should keep in mind that, +number one, interaction is + +strong. +That is, when atomic orbitals + +interact to form molecular +orbitals, the AO interaction is + +strong -- + +-- when there is good spatial +overlap. + +Overlap is a central concept in +molecular orbital theory. + +The idea is that if you have +atoms that are far apart from + +each other in space, +then their wave functions have + +dropped off exponentially and +are not interacting much and + +there is not good overlap. +But when orbitals are close in + +space and if their orbitals are +directed in space toward one + +another, then there may be +overlap that leads to good + +bonding. +And also I can echo this first + +part, AO interaction is strong +when, and say two, + +AOs are close in energy. +The interacting orbitals are + +close in energy. + +When I talk about where atomic +orbitals are in energy, + +I am going to really want you +to think about your periodic + +table and the properties that +appear with periodicity and are + +organized and collated in the +periodic table. + +We are going to be talking +about properties like + +electronegativity as it relates +to the energy. + +And I will get to that a little +bit on the next board, + +but let's first make a small MO +diagram here. + +And this will be a diagram that +we may use both for H two + +or He two. +This is the simplest of all MO + +diagrams and one with which you +should be quite familiar. + +We have a bonding molecular +orbital at low-end energy. + +And notice that if this is a 1s +orbital over here and this is a + +1s orbital over here for H two +or He two + +systems, then when these come +together and bond, + +here are your two nuclei, +-- + +-- and here is a probability +density isosurface that I am + +drawing around that shows +in-phase combination of those + +two 1s orbitals merging with +each other, giving good overlap, + +and the interacting AOs being +of the same energy. + +Because the H two and He +two molecules have such + +symmetry we have a good bonding +orbital. + +And then, up here, +we must find there to be an + +internuclear node in that +corresponding antibonding + +orbital. +And so, it will look something + +like this. +And, therefore, + +I am going to associate with +this high-lying orbital an + +asterisk to indicate the +antibonding character, + +the presence of this +internuclear node, + +the change of sign as we go +from one nucleus to the other, + +the absence of bonding +character. + +Here we have the buildup of +electron density in the + +internuclear region, +electrons being stabilized by + +being held simultaneously by +more than one nucleus that is + +positively charged. +And here, the exact inverse of + +that, constructive interference +and destructive interference in + +the H two or He two +systems. + +And then we can ask, +how many electrons do we have + +to put into the diagram? +If it is the H two case, + +then, to figure out the bond +order, -- + +-- what we do is populate the +diagram according to the same + +kind of Aufbau principle that +you would for generating the + +energy level diagram for an +atom, and taking into account + +things like Hund's rule. +If it is H two, + +we have two electrons that we +can put in, which in here with + +opposing spin, +like that. + +That is our bonding molecular +orbital. + +We have two bonding electrons. +Zero antibonding electrons + +divided by two equals a bond +order of one. + +We have an H-H single bond in +the case of the H two + +molecule. +But if we have He two, + +then in the He two system, +we have two more electrons, + +and the only place they can go +is up here in the antibonding + +molecular orbital. +We have two bonding minus two + +antibonding over two is equal to +zero for a bond order of zero. + +And so, the idea is that if two +He atoms collide with each + +other, when they do so, +their orbitals may overlap and + +give rise to bonding. +But, simultaneously, + +you get antibonding. +And the net bond order is zero, + +and so He two is not +bound, but these atoms just + +bounce off each other. +There is no stabilization. + +And you can certainly +understand that if we were in + +the middle somewhere, +as we would be if we had He two + +plus, +missing one electron up here, + +then our bond order would be +one-half. + +It is going to get a lot more +complicated than this, + +but this you have to know +because this is a really nice + +starting point for thinking +about bonding in all kinds of + +scenarios where you may need to +consider it. + +And so, let's look at some +periodic properties. + +This will be with reference, +again, to energy. + +And I am interested in how some +of the properties of the atoms + +vary as we go across the +periodic table, + +lithium to beryllium to boron +to carbon to nitrogen to oxygen + +and over to fluorine. +And I will stop there. + +We won't worry about any more +of the noble gases today. + +As we go from left to right, +one of the things that you know + +from your study of the periodic +table is that electronegativity + +increases. + +This increases from left to +right across the Periodic Table + +in concert with increasing Z. + +That is, the increasing atomic +number. + +That is, the increasing number +of positively charged protons in + +our nucleus, as we go across. +Each time we are adding more + +protons to that nucleus. +The nucleus is becoming more + +and more positively charged as +we go across. + +And an important consequence of +that has to do with the fact + +that s orbitals don't have a +node at the nucleus. + +Whereas, p orbitals do. +Since these elements are in the + +so-called p block of our +periodic table, + +well, lithium in the s block, +but we will consider the + +properties all the way across. +And the energy issue up here + +that I am going to be concerned +with is the energy of the atomic + +2s versus 2p orbitals as we go +from left to right across the + +periodic table, +systematically adding to the + +number of protons in our nucleus +in a way that does not affect 2s + +orbitals the same way that it +affects 2p orbitals. + +It turns out that by the time +we get over to fluorine, + +where we have essentially our +most electronegative element, + +the 2s orbital has sunk to a +very low energy. + +And the 2p orbital has gone +down in energy as well, + +but just not by nearly as much. +And so, it is nearly an + +isotonic function as we go +across. + +2p is decreasing in energy in +response to this increased Z, + +but not as much as 2s is +decreasing in energy, + +having to do with the fact that +2s electrons see much more of + +the nucleus than 2p electrons do +because 2s electrons don't have + +a node there. +They spend a lot more time in + +close to the nucleus than do +your 2p electrons. + +This has a really important +influence on that set of + +diatomic molecule MO theory +problems, eight orbital + +problems, that we call homo or +heteronuclear diatomic molecules + +of these elements. +And that has to do with the + +fact that in between nitrogen +and oxygen, a fundamental change + +takes place in the energy level +diagram. + +And that change, +that results from the atomic + +structure of the elements, +ends up with the result that + +the MO diagram is much easier to +draw for oxygen, + +O two, +and fluorine, + +F two, +than it is for the earlier + +ones. +And it is much easier to + +understand for O two and +F two than it is for N + +two, C two, B two, +Be two, Li two. + +So, let's just see what that +means. + +First of all, +when we are going to draw an + +energy level diagram for a +diatomic molecule, + +if it is a homonuclear diatomic +molecule, meaning the two atoms + +that are going to be bonded +together are the same, + +that means that the atomic +orbitals for the contributing + +atoms are the same. +Here, on the left, + +what I am drawing is, +let's say, an F or an O atom. + +We have the 2s and the 2p, +x-y-z. + +That is four of the eight +orbitals in our problem. + +And then, over here, +we have the other identical F + +or O atom, with its 2p x-y-z and +2s orbitals at exactly the same + +energy as for the counterpart, +over here. + +So, this is another F or O +atom. + +And then we are going to ask, +how can these atomic orbitals + +combine to give molecular +orbitals in these diatomic + +molecules? +This is unlike the BH three + +problem because there is +no atom at the center of gravity + +of our system, +but the ideas are the same. + +And the ideas are very much the +same as what we have here for H + +two, where also we could +make molecular orbitals despite + +the fact that there was no atom +at the center of our system. + +We can pretend that there is, +and we can use that pretend + +atom to identify what linear +combinations we should make. + +A simpler way to do it, +at this point, + +would be to say that our +molecule has the two nuclei + +oriented along the z-axis. +And then you have x and y + +perpendicular to z. +And so, if we take this choice + +of coordinate system that the +molecule is oriented along z, + +the two nuclei lie one on plus +z, one on minus z. + +Then we can immediately +classify our atomic orbitals as + +being either sigma or pi with +respect to the z-axis. + +I will say AO is sigma or pi +with respect to z, + +which is the molecular axis. +And remember what that means in + +terms of the nodal properties. +If something is sigma with + +respect to z, +that means if you view it down + +z it will look like a cylinder. +It will look like a sphere, + +actually. +It will be cylindrically + +symmetric about the z-axis. +If it is sigma then, + +if you are viewing down z, +you see that. + +That could be either an s +orbital or it could be a pz + +orbital. +They would look the same if you + +were viewing right down z. +And then pi, + +viewing down z, +would look like this. + +And that would be a px or a py +orbital perpendicular to the + +z-axis. +And this would be an s orbital + +or a pz orbital. +What I can say right away is + +that we can separate out the +molecular orbitals that we are + +going to form from these atomic +orbitals into their sigma or pi + +characteristics relative to the +z-axis. + +And because we are in the O or +F atom case, very far on the + +right-hand side the periodic +table, we have a large gap. + +This gap is large. + +We can make the approximation +that this 2s orbital here, + +which could in principle form a +sigma bond with this 2pz orbital + +over here, that would be an +interaction looking like that, + +-- +-- that that does not occur. + +Because remember here I said +you get strong interaction when + +the interacting AOs are close in +energy. + +When you are talking about +these very electronegative + +elements, the s manifold of +orbitals is very well separated + +in energy from the p manifold. +That leads to simplicity in the + +case of the diagram that we are +about to draw. + +Because we say that this +interacts with this in a sigma + +fashion, giving rise to bonding +and antibonding interactions + +that look exactly like what we +have drawn over there. + +I will draw the bonding orbital +here. + +Actually, the antibonding +orbital here and the bonding + +orbital here. +And I will show the parentage + +of this molecular orbitals in +this way. + +And you will recognize that +this is our in-phase combination + +and this is our out-of-phase +combination, analogous to the H + +two problem. +This is like the H two + +problem built into the F two +or the O two + +problem. +And next what we find is that + +we can also make a sigma bond by +interaction of pz with pz. + +This is going to be a nice +strong directed bonding + +interaction that will look like +this. + +You see we have overlap here in +the center, a nice strong + +bonding interaction in the +center with 2pz orbitals that + +are directed at each other. +And this is a sigma bond + +because you view that down z, +it is going to look like a + +round thing. +You are not going to see any + +nodal surfaces. +And then it has up here a + +corresponding antibonding +orbital right there. + +So far I have -- + +-- two pair-wise combinations +that give us two sigma bonding + +orbitals and two sigma star +antibonding orbitals. + +So, that is pretty +straightforward. + +And, once again, +I can say that we have the H + +two problem built into +this energy level diagram twice, + +with the s interactions, +with the pz interactions. + +The only thing I have left is +to do my px and py interactions. + +And we can make a pair of pi +bonds and a pair of pi + +anti-bonds that corresponds to +those pi bonds. + +This one is pi. +This one is pi star. + +And what do they look like? +Well, they look like + +side-to-side bonds between pairs +of p orbitals. + +This is just like what I showed +you for the ethylene molecule. + +The pi bond, +in fact, has this nice overlap + +on one side and up here on the +other. + +There is your pi bond. +And you have one of those that + +lie in the x,z-plane and one of +those that lie in the y,z-plane. + +You have two of them, +and they are at equal energy + +here. +And then up here, + +what does the pi star look +like? + +Well, the same, +except we turn around one of + +the p orbitals, +introducing a nodal surface, + +like that. +And we have two of those. + +And here is our nodal surface. +Now it is an internuclear + +between the nuclei nodal +surface, indicating antibonding + +character there. +That is the easy case because s + +and p are very well separated. +What you can see, + +though, is that type of +interaction of a 2s on our left + +atom with a pz on the right +atom, that might start to become + +important as you are over here +in this part of the diagram, + +where s and p are pretty close +together in energy. + +And that is what happens, +in fact. + +And that is what happens as +soon as you go to the left of + +oxygen and to nitrogen or +anything lighter than nitrogen. + +Suddenly, you cannot ignore +interactions of s on one side + +with p on the other. + +And so, I am going to draw here +the diagram that you would use, + +say, for N two. +And, for simplicity, + +I am just going to draw the +middle part. + +This part here in the middle is +that which corresponds to the + +molecule. +This one is what you would use + +for O two or F two. + +And let's just go ahead and +draw that diagram for the + +molecule. +This one would be this set of + +energy levels corresponding to, +for example, N two. + +And we have increasing energy + +on the vertical axis. +We are going to find that + +again, we have a sigma and a +sigma star. + +And then, the difference comes +right here where we find that as + +we go up in energy we next get +to our pi bonds. + +And then, the next sigma +orbital is slightly higher in + +energy than the pi system rather +than slightly lower in energy. + +And then we will encounter up +here our pi star. + +And then, finally, +that highest in energy, + +sigma star. +This switch, + +this sigma going up relative to +that pi is really a consequence + +of all of the sigma orbitals +being responsive to the value of + +the electronegativity of the 2s +orbital of the atom. + +You can really almost consider +the pi system independent from + +the sigma. +These four sigma orbitals, + +sigma, sigma star, +sigma, sigma star, + +I can call them one sigma, +two, three, four, + +just to show you that we have, +in ascending order, + +four orbitals of sigma +symmetry. + +That whole manifold, +when you can start mixing a + +little bit of very low energy s +into it, sinks down relative to + +pi. +In the case over here, + +we are basically pulling down +the four sigma orbitals relative + +to pi. +And here, because our s + +orbitals are higher in energy +relative to our p orbitals, + +they go up a little bit and +bumps three sigma up over pi. + +And what it means is that these +orbitals are not so simple + +anymore. +Any one of them is a linear + +combination of four atomic +orbitals. + +This orbital here, +one sigma, will not look like + +it looks in the H two +problem, anymore. + +This one sigma will have some p +mixed into it. + +And so, one way we can +represent that through a simple + +drawing is like this. + +You see the difference between +that sigma bonding orbital and + +the one up there? +We have some extra little nodes + +in here that are an inherent +characteristic of the + +contribution of 2pz orbitals +into this. + +This is a linear combination of +the 2s and the 2pz orbitals on + +the two atoms we have. +There are four atomic orbitals + +that go in with different +coefficients to these different + +parts of the sigma manifold. +And then up here, + +the other bonding orbital, +we can draw it this way. + +And this molecular orbital, +this one here, + +three sigma, +has diminished bonding + +character between the two nuclei +and enhanced character on the + +outside, the part of the p +orbital that is contributing to + +it that points away from the +other atom. + +And so, while this has bonding +character, it also has what we + +might think of as lone pair +characteristics. + +In MO theory, +some orbitals are not that + +simple. +They might be at the same time + +a little bit bonding and a +little bit lone pair in + +character. +Let's look at a couple of + +orbitals like that, +briefly. + +And here I have done this for +the C two molecule. + +I have done the calculation for +C two, + +so now we are over here on the +left-hand side of that dividing + +line where s and p are a big +closer together. + +And I am opening up this +orbital, this one down here. + +It is a little more complicated +than the way I drew it on the + +board, but what you should be +able to see is -- + +Think back, now, +to the first orbital I showed + +you today, which was the lowest +lying orbital in the BH three + +molecule. +You remember, + +no matter which way we turned +it, we only saw blue, + +which was the positive wave +function. + +It looked like an s orbital, +everywhere. + +It had the same sign +everywhere, and you could not + +see any nodal properties. +Well, that would be true also + +for this one down here in the +case of O two or F two + +because it is not mixing +in p character. + +Because the atomic s and p +orbitals are so far away in + +energy. +But now, when they are closer + +in energy, this orbital down +here, the s over here sees the p + +over here and they mix in, +and vice versa. + +And, if I turn this around, +what you are going to see are + +these little negative lobes here +that I am indicating that are + +mixing in. +But this is hugely bonding + +orbital, still, +because look at how much of the + +orbital is centered in the +region between the nuclei. + +This is a very strongly bonding +orbital in this system. + +Let's now visualize the three +sigma, the third sigma symmetry + +orbital, as we ascend in energy. +And it will look hopefully + +something like what I drew here. +There it is. + +You see this is a sigma +orbital, because as we look down + +the z-axis, it looks just round. +But it certainly has a lot of p + +orbital character because as we +go from outside the molecule + +through the nucleus, +we get a change in sign. + +And then there is overlap in +here, but the amount of the + +overlap in here is small +compared to the amount of this + +lobe out here that is just +nonbonding in character because + +it is pointing out into space. +It is like a lone pair of + +electrons at the same time as it +is a bonding orbital. + +If this molecule actually had +enough electrons to fill up + +through three sigma and no +higher, than you would recognize + +that this orbital that we are +looking at would be the highest + +occupied molecular orbital. +And it would be responsible for + +the basicity and the +nucleophilicity of the molecule + +-- +-- because any Lewis acid that + +came in would want to come in on +the z-axis to interact with this + +lone pair electron density out +there. + +So, that is how our three sigma +orbital now looks when we are on + +the left side of that red dotted +line to the lighter elements. + +I will leave that up there for +a moment while we consider a + +couple of interesting points. +One of the things that you will + +often be asked to do is to write +down the configuration. + +And I want to finish these two +questions here of O two, + +why does it have unpaired +electrons? + +In the case of O two, +we are over on this diagram, + +we have 12 valance electrons. +We can go two, + +four, six, eight, +ten, and then 11 and 12, + +two electrons up here in the pi +star manifold. + +We are completely filled up +through pi. + +And then, we have a half-filled +pi star with 12 electrons + +populating the O two diagram. + +Let's represent that this way. +We have our one sigma with two + +electrons in. +We have our second sigma, + +which is antibonding with two +electrons. + +Then we have our third sigma +with two electrons. + +And then, as we go up in +energy, the next is our first pi + +orbital bonding. +That accommodates four + +electrons. +And then we have next our + +second pi type orbital. +It is antibonding and has two + +electrons in it. +And then all the other orbitals + +are empty, so I won't indicate +them. + +This is the configuration for +the O two molecule. + +That means, we come back over +here, by Hund's rule of maximum + +multiplicity, +we have two spin-up electrons + +in the O two molecule +with all these other orbitals + +down here being filled. +That configuration that I wrote + +down for the O two molecule over +there is a very shorthand way of + +representing the MO energy level +diagram -- + +-- because I started here at +the lowest energy, + +and I went up in energy like +this. + +And what you can see is sigma +star cancels sigma, + +so no bonding there. +We have here three electron + +pairs in bonding orbitals, +sigma and 2pi, + +but we have two electrons that +are unpaired electrons, + +responsible for the +paramagnetism of the O two + +molecule, +that cancel some of the bonding + +down here. +When we want to write that down + +in terms of our bond order +convention, we have six bonding + +electrons minus two antibonding +electrons over two, + +which is going to be equal to a +bond order of two. + +That is our bond order for O +two. + +While the bond order is what we +expect to find based on that + +valance bond representation of O +two up there, + +what we find out is that the +representation of O two up there + +in the valance bond terminology +would not tell us that the + +molecule should actually have +two electrons that are not + +paired in the molecule, +-- + +-- that it should have +paramagnetism due to the lack of + +pairing up of all the electrons, +spin pairing in the molecule. + +And it has to do with this high +symmetry of the O two molecule. + +And it cannot distort from high + +symmetry because it has just two +atoms. + +It has very few degrees of +freedom. + +It cannot bend or something to +get those electrons to pair up, + +and so they are unpaired. +And that is why dioxegen has + +unpaired electrons. +And then, if we go to nitrogen, + +the order that we write these +things down in is a little + +different because the energy +level diagram is different + +because now s and p are closer +together. + +And what we have is one sigma +with two electrons, + +or two sigma star with two +electrons. + +And then, next, +we have our one pi with its + +four electrons. +And then next, + +we have our three sigma with +its two electrons. + +And that is it. +We have two less electrons in + +the system than we do in +O two. + +That is N two. +And our bond order now is + +three. +That is in accord with our + +Lewis structure of N two, +but it is a triple bond. + +And it is a triple bond in a +molecule that is completely + +non-polar. +And it is one of the strongest + +chemical bonds known. +That triple bond is worth about + +226 kilocalories per mole. +And it makes N two a + +very fascinating molecule. +And, of course, + +it is the major constituent of +our atmosphere. + +And it is very inert, +due to the stability associated + +with having this diagram +populated up all through the + +bonding orbitals, +and then no more antibonding + +electrons present in the system. +So, that is pretty interesting. + +And given the time, +I think I will leave you after + +the following. +I just want to show you one + +more picture as a prelude to +where I will start next time. + +And that has to do with what +happens when the two atoms that + +are bonding are different. +Let's look at the three sigma + +orbital for the carbon monoxide +molecule. + +It would look like it does for +N two. + +It is the same number of +electrons. + +But look here. +It is very asymmetric. + +And that has to do with the +fact that carbon and oxygen have + +very different +electronegativity. + +And so, this highest occupied +molecular orbital for carbon + +monoxide, again, +an eight orbital problem, + +and again, a ten electron +system, is one where we have a + +larger coefficient on the lone +pair piece that is on the carbon + +atom of the molecule. +And I will start off with this + +next time, but that is one of +two reasons why CO is a poison. + +Have a nice weekend. \ No newline at end of file diff --git a/UiZlaJX3IRk.txt b/UiZlaJX3IRk.txt new file mode 100644 index 0000000000000000000000000000000000000000..8bdf1816bd7c34afb4965274909c5a5568597a89 --- /dev/null +++ b/UiZlaJX3IRk.txt @@ -0,0 +1,2031 @@ +The following content is +provided under a Creative + +Commons license. + +Your support will help MIT +OpenCourseWare continue to + +offer high quality educational +resources for free. + +To make a donation or view +additional materials from + +hundreds of MIT courses, visit +MIT OpenCourseWare at + +ocw.mit.edu + +PROFESSOR: Good morning. + +Oh, it's so nice to +get a response. + +Thank you. + +I appreciate it. + +i have a confession to make. + +I stopped at my usual candy +store this morning and they + +didn't have any. + +So I am bereft of anything +other than crummy little + +Tootsie Rolls for today. + +But I promise I'll have a +new supply by Thursday. + +We ended up the last lecture +looking at pseudocode for + +k-means clustering and talking +a little bit about the whole + +idea and what it's doing. + +So I want to start today by +moving from the pseudocode to + +some real code. + +This was on a previous +handout but it's + +also on today's handout. + +So let's look at it. + +Not so surprisingly I've chosen +to call it k-means. + +And you'll notice that it's +got some arguments. + +The point to be clustered, +k, and that's + +an interesting question. + +Unlike hierarchical clustering, +where we could run + +it and get what's called a +dendrogram and stop at any + +level and see what we liked, +k-means involves knowing in + +the very beginning how many +clusters we want. + +We'll talk a little bit about +how we could choose k. + +A cutoff. + +What the cutoff is doing, you +may recall that in the + +pseudocode k-means was +iterative and we keep + +re-clustering until the change +is small enough that we feel + +it's stable. + +That is to say, the new clusters +are not that much + +different from the +old clusters. + +The cutoff is the definition +of what we + +mean by small enough. + +We'll see how that gets used. + +The type of point +to be clustered. + +The maximum number +of iterations. + +There's no guarantee that +things will converge. + +As we'll see, they usually +converge very quickly in a + +small number of iterations. + +But it's prudent to have +something like this just in + +case things go awry. + +And to print. + +Just my usual trick of being +able to print some debugging + +information if I need it, but +not getting buried in output + +if I don't. + +All right. + +Let's look at the code. + +And it very much follows the +outline of the pseudocode we + +started with last time. + +We're going to start by +choosing k initial + +centroids at random. + +So I'm just going to go and take +all the points I have. + +And I'm assuming, by the way, +I should have written this + +down probably, that I have +at least k points. + +Otherwise it doesn't +make much sense. + +If you have 10 points, +you're not + +going to find 100 clusters. + +So I'll take k random centroids, +and those will be + +my initial centroids. + +There are more sophisticated +ways of choosing centroids, as + +discussed in the problem set, +but most of the time people + +just choose them at random, +because at least if you do it + +repetitively it guarantees +against some sort of + +systematic error. + +Whoa. + +What happened? + +I see. + +Come back. + +Thank you. + +All right. + +Then I'm going to say that +the clusters I have + +initially are empty. + +And then I'm going to create a +bunch of singleton clusters, + +one for each centroid. + +So all of this is just +the initialization, + +getting things going. + +I haven't had any +iterations yet. + +And the biggest change so far +I'm just setting arbitrarily + +to the cutoff. + +All right. + +And now I'm going to iterate +until the change is smaller + +than the cutoff while biggest +change is at least the cutoff. + +And just in case numIters is +less than the maximum, I'm + +going to create a list +containing k empty list. + +So these are the new clusters. + +And then I'm going to go through +for i in range k. + +I'm going to append +the empty cluster. + +These are going to +be the new ones. + +And then for p and all the +points I'm going to find the + +centroid in the existing +clustering + +that's closest to p. + +That's what's going on here. + +Once I've found that, I'm going +to add p to the correct + +cluster, go and do it +for the next point. + +Then when I'm done, I'm going to +compare the new clustering + +to the old clustering and +get the biggest change. + +And then go back and +do it again. + +All right? + +People, understand that basic +structure and even some of the + +details of the code. + +It's not very complicated. + +But if you haven't seen +it before, it can be + +a little bit tricky. + +When I'm done I'm going to just +get some statistics here + +about the clusters, going to +keep track of the number of + +iterations and the maximum +diameter of a cluster, so the + +cluster in which things are +least tightly grouped. + +And this will give me an +indication of how good a + +clustering I have. + +OK? + +Does that make sense +to everybody? + +Any questions about +the k-means code? + +Well, before we use it, let's +look at how we use it. + +I've written this function +testOne that uses it. + +Some arbitrary values +for k in the cutoff. + +Number of trials is kind +of boring here. + +I've only said one is the +default and I've set print + +steps to false. + +The thing I want you to notice +here, because I'm choosing the + +initial clustering at random, +I can get different results + +each time I run this. + +Because of that, I might want +to run it many times and + +choose the quote, "best +clustering." What metric am I + +using for best clustering? + +It's a minmax metric. + +I'm choosing the minimum of +the maximum diameters. + +So I'm finding the worst cluster +and trying to make + +that as good as I can make it. + +You could look at the +average cluster. + +This is like the linkage +distances we + +talked about before. + +That's the normal +kind of thing. + +It's like when we did Monte +Carlo simulations or random + +walks, flipping coins. + +You do a lot of trials and then +you can either average + +over the trials, which wouldn't +make sense for the + +clustering, or select the +trial that has some + +property you like. + +This is the way people +usually use k-means. + +Typically they may do 100 trials +and choose the best, + +the one that gives them +the best clustering. + +Let's look at this, and let's +try it for a couple of + +examples here. + +Let's start it up. + +And we'll just run test one on +our old mammal teeth database. + +We get some clustering. + +Now we'll run it again. + +We get a clustering. + +I don't know, is it the +same clustering? + +Kind of looks like it is. + +No reason to suspect +it would be. + +We run it again. + +Well you know, this is +very unfortunate. + +It's supposed to give different +answers here because + +it often does. + +I think they're the same +answers, though. + +Aren't they? + +Yes? + +Anyone see a difference? + +No, they're the same. + +How unlucky can you be? + +Every time I ran it at my desk +it came up the first two times + +with different things. + +But take my word for it, and +we'll see that with other + +examples, it could come out +with different answers. + +Let's try it with some +printing on. + +We get some things here. + +Let's try it. + +What have we got out +of this one? + +All right. + +Oh, well. + +Sometimes you get lucky and +sometimes you get unlucky with + +randomness. + +All right. + +So, why did we start +with k-means? + +Not because we needed it +for the mammals' teeth. + +The hierarchical worked fine, +but because it was too slow + +when we tried to look +at something + +big like the counties. + +So now let's move on and talk +about clustering the counties. + +We'll use exactly the +k-means code. + +It's one of the reasons we're +allowed to pass in the point + +type as an argument. + +But the interesting thing will +be what we do for the counties + +themselves. + +This gets a little +complicated. + +In particular, what I've added +to the counties is this notion + +of a filter. + +The reason I've done this is, +as we've seen before, the + +choice of features can make +a big difference in what + +clustering you get. + +I didn't want to do a lot of +typing as we do in these + +examples, so what I did is I +created a bunch of filters. + +For example, no wealth, which +says, all right, we're not + +going to look at home value. + +We're giving that +a weight of 0. + +We're giving income a weight +of 0, we're giving poverty + +level a rate of 0. + +But we're giving the +population a + +weight of 1, et cetera. + +OK. + +What we see here is each filter +supplies the weight, in + +this case either 0 or +1, to a feature. + +This will allow me as we +go forward to run some + +experiments with different +features. + +All features, everything +has a weight of 1. + +I made a mistake though. + +That should have been a 1. + +Then I have filter names, which +are just a dictionary. + +And that'll make it easy for +me to run various kinds of + +tests with different filters. + +Then I've got init, which takes +as its arguments the + +things you would expect, +plus the filter name. + +So it takes the original +attributes, the normalized + +attributes. + +And you will recall that, why +do we need to normalize + +attributes? + +If we don't, we have something +like population, which could + +number in the millions, and +we're comparing it to percent + +female, which we know cannot +be more than a 100. + +So the small values become +totally dominated by the big + +absolute values and when we run +any clustering it ends up + +only looking at population or +number of farm acres, or + +something that's big. + +Has a big dynamic range. + +Manhattan has no farm acres. + +Some county in Iowa has a lot. + +Maybe they're identical in +every other respect. + +Unlikely, but who knows? + +Except I guess there's no +baseball teams in Iowa. + +But at any rate, we always scale +or we try and normalize + +so that we don't get +fooled by that. + +Then I go through and, if I +haven't already, this is a + +class variable attribute +filter, which is + +initially set to none. + +Not an instance variable, +but a class variable. + +And what we see here is, if that +class variable is still + +none, this will mean it's the +first time we've generated a + +point of type county, then what +we're going to do is set + +up the filter to only look at +the attributes we care about. + +So only the attributes which +have a value of 1. + +And then I'm going to override +distance from class point to + +look at the features +we care about. + +OK. + +Does this basic structure and +idea make sense to people? + +It should. + +I hope it does, because the +current problem set requires + +you to understand it in which +you all will be doing some + +experiments. + +So now I want to do some +experiments with it. + +I'm not going to spend too +much time, even though it + +would be fun, because I don't +want to deprive you of the fun + +of doing your problem sets. + +So let's look at an example. + +I've got test, which is pretty +much like testOne. + +Runs k-means number of times +and chooses the best. + +And we can start. + +Well, let's start by running +some examples ourselves. + +So I'm going to start +by clustering on + +education level only. + +I'm going to get 20 clusters, 20 +chosen just so it wouldn't + +take too long to run, and we'll +filter on education. + +And we'll see what we get. + +Well, I should have probably +done more than one cluster + +just to make it work. + +But we've got it and just for +fun I'm keeping track of what + +cluster Middlesex County, the +county in which MIT shows up. + +So we can see that +it's similar to a + +bunch of other counties. + +And it happens to have an +average income of $28,665, or + +at least it did then. + +And if we look, we +should also see-- + +no, let me go back. + +I foolishly didn't uncomment +pyLab.show. + +So we better go back +and do that. + +Well, we're just going to nuke +it and run it again because + +it's easy and I wanted +to run it with a + +couple of trials anyway. + +So, we'll first do +the clustering. + +We get cluster 0. + +Now we're getting +a second one. + +It's going to choose whichever +was the tightest. + +And we'll see that that's +what it looks like. + +So we've now clustered the +counties based on education + +level, no other features. + +And we see that it's got some +interesting properties. + +There is a small number of +counties, clusters, out here + +near the right side +with high income. + +And, in fact, we'll see +that we are fortunate + +to be in that cluster. + +One of the clusters that +contains wealthy counties. + +And you could look at it and see +whether you recognize any + +of the other counties that +hang out with Middlesex. + +Things like Marin County, +San Francisco County. + +Not surprisingly. + +Remember, we're clustering by +education and these might be + +counties where you would expect +the level of education + +to be comparable to the level +of education in Middlesex. + +All right. + +Let me get rid of +that for now. + +Sure. + +I ran it. + +I didn't want you to have to sit +through it, but I ran it + +on a much bigger sample size. + +So here's what I got +when I ran it + +asking for 100 clusters. + +And I think it was 5 trials. + +And you'll notice that this +case, actually, we have a much + +smaller cluster containing +Middlesex. + +Not surprising, because I've +done 100 rather than 20. + +And it should be pretty tight +since I chose the best-- + +you can see we have a +distribution here. + +Now, remember that the name of +the game here is we're trying + +to see whether we can infer +something interesting by + +clustering. + +Unsupervised learning. + +So one of the questions we +should ask is, how different + +is what we're getting here +from if we chose + +something at random? + +Now, remember we did +not cluster on + +things based on income. + +I happened to plot income here +just because I was curious as + +to how this clustering +related to income. + +Suppose we had just chosen at +random and split the counties + +at random into 100 different +clusters, What would you have + +expected this kind of +graph to look like? + +Do we have something that +is different, obviously + +different, from what we might +have gotten if we'd just done + +a random division into 100 +different clusters? + +Think about it. + +What would you get? + +AUDIENCE: A bell curve? + +PROFESSOR: Pardon? + +AUDIENCE: We'd get +a bell curve. + +PROFESSOR: Well, a bell curve +is a good guess because bell + +curves occur a lot in nature. + +And as I said, I apologize for +the rather miserable quality + +of the rewards. + +It's a good guess but I think +it's the wrong guess. + +What would you expect? + +Would you expect the different +clusters-- + +yeah, go ahead. + +AUDIENCE: You probably might +expect them all to average at + +a certain point for a very +sharp bell curve? + +PROFESSOR: A very sharp bell +curve was one comment. + +Well, someone else +want to try it? + +That's kind of close. + +I thought you were on the right +track in the beginning. + +Well, take a different +example. + +Let's take students. + +If I were to select a 100 MIT +students at random and compute + +their GPA, would you it to be +radically different from the + +GPA of all of MIT? + +The average GPA of +all MIT students? + +Probably not, right? + +So if I take 100 counties and +put them into a cluster, the + +average income of that cluster +is probably pretty close to + +the average income +in the country. + +So you'd actually expect it +to be kind of flat, right? + +That each of the randomly chosen +clusters would have the + +same income, more or less. + +Well, that's clearly not +what we have here. + +So we can clearly infer from the +fact that this is not flat + +that there is some interesting +correlation between level of + +income and education. + +And for those of us who earn our +living in education, we're + +glad to see it's positive, +actually. + +Not negative. + +As another experiment, +just for fun, I + +clustered by gender only. + +So this looked only +at the female/male + +ratio in the counties. + +And here you'll see Middlesex +is with-- + +remember we had about 3,000 +counties to start with. + +So the fact that there were +so few in the cluster on + +education was interesting, +right? + +Here we have more. + +And we get a very +different-looking picture. + +Which says, perhaps, that the +female/male ratio is not + +unrelated to income, but it's +a rather different relation + +than we get from education. + +This is what would be called +a bi-modal distribution. + +A lot here and a lot here and +not much in the middle. + +But again the dynamic range +is much smaller. + +But we do have some +counties where the + +income is pretty miserable. + +All right. + +We could play a lot more with +this but I'm not going to. + +I do want to, before we leave +it, because we're about to + +leave machine learning, +reiterate a few of the major + +points that I wanted +to make sure were + +the take home messages. + +So, we talked about supervised +learning much less than we + +talked about unsupervised. + +Interestingly, because +unsupervised learning is + +probably used more often in the +sciences than supervised. + +And when we did supervised +learning, we started with a + +training set that had labels. + +Each point had a label. + +And then we tried to infer the +relationships between the + +features of the points and +the associated labels. + +Between the features +and the labels. + +We then looked at unsupervised +learning. + +The issue here was, our +training set was + +all unlabeled data. + +And what we try and infer is +relationships among points. + +So, rather than trying to +understand how the features + +relate to the labels, we're just +trying to understand how + +the points, or actually, the +features related to the + +points, relate to one another. + +Both of these, as I said +earlier, are similar to what + +we saw when we did regression +where we tried to + +fit curves to data. + +You need to be careful and wary +of over-fitting just as + +you did with regression. + +In particular, if the training +data is small, a small set of + +training data, you may learn +things that are true of the + +training data that are not true +of the data on which you + +will subsequently run the +algorithm to test it. + +So you need to be +wary of that. + +Another important lesson is +that features matter. + +Which features matter? + +It matters whether they're +normalized. + +And in some cases you can even +weight them if you want to + +make some features more +important than the others. + +Features need to be relevant to +the kind of knowledge that + +you hope to acquire. + +For example, when I was trying +to look at the eating habits + +of mammals, I chose features +based upon teeth, not features + +based upon how much hair they +had or their color of the + +lengths of the tails. + +I chose something that I had +domain knowledge which would + +suggest that it was probably +relevant to + +the problem at hand. + +Question at hand. + +And then we discovered it was. + +Just as here, I said, well, +maybe education has something + +to do with income. + +We ran it and we discovered, +thank goodness, that it does. + +OK. + +So I probably told you ten times +that features matter. + +If not, I should have +because they do. + +And it's probably the most +important thing to get right + +in doing machine learning. + +Now, our foray into machine +learning is part of a much + +larger unit. + +In fact, the largest unit of +the course really, is about + +how to use computation to make +sense of the kind of + +information one encounters +in the world. + +A big part of this is finding +useful ways to abstract from + +the situation you're initially +confronted with to create a + +model about which +one can reason. + +We saw that when we +did curve fitting. + +We would abstract from +the points to a + +curve to get a model. + +And we see that with machine +learning, that we abstract + +from every detail about a county +to say, the education + +level, to give us a model +of the counties + +that might be useful. + +I now want to talk about another +kind of way to build + +models that's as popular +a way as there is. + +Probably the most common +kinds of models. + +Those models are graph +theoretic. + +There's a whole rich theory +about graphs and graph theory + +that are used to understand +these models. + +Suppose, for example, you had +a list of all the airline + +flights between every city in +the United States and what + +each flight cost. + +Suppose also, counterfactual +supposition, that for all + +cities A, B and C, the cost of +flying from A to C by way of B + +was the cost of A to B and the +cost from B to C. We happen to + +know that's not true, but +we can pretend it is. + +So what are some of the +questions you might ask if I + +gave you all that data? + +And in fact, there's a company +called ITA Software in + +Cambridge, recently acquired by +Google for, I think, $700 + +million, that is built upon +answering these kinds of + +questions about these +kinds of graphs. + +So you could ask, for example, +what's the shortest number of + +hops between two cities? + +If I want to fly from here to +Juneau, Alaska, what's the + +fewest number of stops? + +I could ask, what's the +least expensive-- + +different question-- flight +from here to Juneau. + +I could ask what's the least +expensive way involving no + +more than two stops, just in +case I don't want to stop too + +many places. + +I could say I have ten cities. + +What's the least expensive +way to visit each + +of them on my vacation? + +All of these problems are nicely +formalized as graphs. + +A graph is a set of nodes. + +Think of those as objects. + +Nodes are also often called +vertices or a + +vertex for one of them. + +Those nodes are connected +by a set of edges, + +often called arcs. + +If the edges are +uni-directional, the + +equivalent of a one-way street, +it's called a digraph, + +or directed graph. + +Graphs are typically used in +situations in which there are + +interesting relationships +among the parts. + +The first documented use of this +kind of a graph was in + +1735 when the Swiss +mathematician Leonard Euler + +used what we now call graph +theory to formulate and solve + +the Konigberg's Bridges +problem. + +So this is a map of Konigsberg, +which was then the + +capital of East Prussia, a part +of what's today Germany. + +And it was built at the +intersection of two rivers and + +contained a lot of islands. + +The islands were connected to +each other and to the mainland + +by seven bridges. + +For some bizarre reason which +history does not record and I + +cannot even imagine, the +residents of this city were + +obsessed with the question of +whether it was possible to + +take a walk through the city +that involved crossing each + +bridge exactly once. + +Could you somehow take a walk +and go over each bridge + +exactly once? + +I don't know why they cared. + +They seemed to care. + +They debated it, they walked +around, they did things. + +It probably would be unfair for +me to ask you to look at + +this map and answer +the question. + +But it's kind of complicated. + +Euler's great insight was that +you didn't have to actually + +look at the level of detail +represented by this map to + +answer the question. + +You could vastly simplify it. + +And what he said is, well, let's +represent each land mass + +by a point, and each +bridge as a line. + +So, in fact, his map of +Konigsberg looked like that. + +Considerably simpler. + +This is a graph. + +We have some vertices +and some edges. + +He said, well, we can just look +at this problem and now + +ask the question. + +Once he reformulated the problem +this way it became a + +lot simpler to think about and +he reasoned as follows. + +If a walk were to traverse each +bridge exactly once, it + +must be the case that each node, +except for the first and + +the last, in the walk must have +an even number of edges. + +So if you were to go to an +island and leave the island + +and traverse each bridge to the +island unless there were + +an even number, you +couldn't traverse + +each one exactly once. + +If there were only one bridge, +once you got to the island you + +were stuck. + +If there were two bridges you +could get there and leave. + +But if there were three bridges +you could get there, + +leave, get there and +you're stuck again. + +He then looked at it and said, +well, none of these nodes have + +an even number of edges. + +Therefore you can't do it. + +End of story. + +Stop arguing. + +Kind of a nice piece of logic. + +And then Euler later went on to +generalize this theorem to + +cover a lot of other +situations. + +But what was important was not +the fact that he solved this + +problem but that he thought +about the notion of taking a + +map and formulating +it as a graph. + +This was the first example of +that and since then everything + +has worked that way. + +So if you take this kind of idea +and now you extend it to + +digraphs, you can deal +with one-way + +bridges or one-way streets. + +Or suppose you want to look at +our airline problem, you can + +extend it to include weights. + +For example, the number of miles +between two cities or + +the amount of toll you'd have +to pay on some road. + +So, for example, once you've +done this you can easily + +represent the entire US highway +system or any roadmap + +by a weighted directed graph. + +Or, used more often, probably, +the World Wide Web is today + +typically modeled as a directed +graph where there's + +an edge from page A to page B, +if there's a link on page A to + +page B. + +And then maybe if you want to +care, ask the question how + +often do people go from A to B, +a very important question, + +say, to somebody like Google, +who wants to know how often + +people click on a link to get +to another place so they can + +charge for those clicks, you +use a weighted graph, which + +says how often does someone +go from here to there. + +And so a company like Google +maintains a model of what + +happens and uses a weighted, +directed graph to essentially + +represent the Web, the clicks +and everything else, and can + +do all sorts of analysis +on traffic patterns + +and things like that. + +There are also many less +obvious uses of graphs. + +Biologists use graphs to measure +things ranging from + +the way proteins interact with +each other to, more obviously, + +gene expression networks +are clearly graphs. + +Physicists use graphs to model +phase transitions with + +typically the weight of the edge +representing the amount + +of energy needed to go from +one phase to another. + +Those are again weighted +directed graphs. + +The direction is, can you get +from this phase to that phase? + +And the weight is how much +energy does it require? + +Epidemiologists use graphs to +model diseases, et cetera. + +We'll see an example +of that in a bit. + +All right. + +Let's look at some code now +to implement graphs. + +This is also in your handout and +I'm going to comment this + +out just so we don't +run it by accident. + +As you might expect, I'm +going to use classes + +to implement graphs. + +I start with a class node +which is at this + +point pretty simple. + +It's just got a name. + +Now, you might say, well, why +did I even bother introducing + +a class here? + +Why don't I just use strings? + +Well, because I was kind of +wary that sometime later I + +might want to associate more +properties with nodes. + +So you could imagine if I'm +using a graph to model the + +World Wide Web, I don't want +more than the URL for a page. + +I might want to have all the +words on the page, or who + +knows what else about it. + +So I just said, for safety, +let's start with a simple + +class, but let's make it a class +so that any code I write + +can be reused if at some later +date I decide nodes are going + +to be more complicated +than just strings. + +Good programming practice. + +An edge is only a little +bit more complicated. + +It's got a source, a +destination, and a weight. + +So you can see that I'm using +the most general form of an + +edge so that I will be able use +edges not only for graphs + +and digraphs, but also weighted +directed graphs by + +having all the potential +properties I might need and + +then some simple things +to fetch things. + +The next cluster in the +hierarchy is a digraph. + +So it's got an init, of course, +I can add nodes to it. + +I'm not going to allow myself +to add the same + +node more than once. + +I can add edges. + +And I'm going to check to make +sure that I'm only connecting + +nodes that are in the graph. + +Then I've got children of, +which gives me all the + +descendants of a node, and +has node in string. + +And then interestingly enough, +maybe surprising to some of + +you, I've made graph a +sub-class of digraph. + +Maybe that seems a little odd. + +After all, when I started +I started + +talking about digraphs. + +About graphs, and then said, and +we can add this feature. + +But now I'm going the +other way around. + +Why is that? + +Why do you think that's +the right way + +to structure a hierarchy? + +What's the relation of +graphs to digraphs? + +Digraphs are more general +than graphs. + +A graph is a specialization +of a digraph. + +Just like a county is a +specialization of a point. + +So, typically as you design +these class hierarchies, the + +more specialized something is, +the further it has to be down. + +More like a subclass. + +Does that make sense? + +I can't really turn +this on its head. + +I can specialize a digraph +to get a graph. + +I can't specialize a graph +to get a digraph. + +And that's why this hierarchy +is organized the way it is. + +What else is there are +interesting to say about this? + +A key question, probably the +most important question in + +designing and implementation +of graphs, is the choice of + +data structures to represent +the digraph in this case. + +There are two possibilities +that people typically use. + +They can use an adjacency +matrix. + +So if you have N nodes, you have +an N by N matrix where + +each entry gives, in the case +of a digraph, a weighted + +digraph, the weight-connecting +nodes on that edge. + +Or in the case of a graph it +can be just true or false. + +So this is, can I +get from A to B? + +Is that going to +be sufficient? + +Suppose you have a graph +that looks like this. + +And we'll call that Boston +and this New York. + +And I want to model the roads. + +Well, I might have a road that +looks like this and a road + +that looks like this from +Boston to New York. + +As in, I might have more +than one road. + +So I have to be careful when +I use an adjacency matrix + +representation, to realize +that each element of the + +matrix could itself be somewhat +more complicated in + +the case that there +are multiple edges + +connecting two nodes. + +And in fact, in many graphs we +will see there are multiple + +edges connecting the +same two nodes. + +It would be surprising +if there weren't. + +All right. + +Now, the other common +representation is + +an adjacency list. + +In an adjacency list, for every +node I list all of the + +edges emanating from +that node. + +Which of these is better? + +Well, neither. + +It depends upon your +application. + +An adjacency matrix is often +the best choice when the + +connections are dense. + +Everything is connected +to everything else. + +But is very wasteful if the +connections are sparse. + +If there are no roads connecting +most of your cities + +or no airplane flights +connecting most of your + +cities, then you don't want to +have a matrix where most of + +the entries are empty. + +Just to make sure that people +follow the difference, which + +am I using in my implementation +here? + +Am I using an adjacency matrix +or an adjacency list? + +I heard somebody say an +adjacency list and because my + +candy supply is so meager they +didn't even bother raising in + +their hand so I know +who said it. + +But yes, it is an +adjacency list. + +And we can see that by +looking what happens + +when we add an edge. + +I'm associating it with +the source node. + +So from each node, and we can +see that when we look at the + +children of-- + +here, I just return the +edges of that node. + +And that's the list of all +the places you can get + +to from that node. + +So it's very simple, but +it's very useful. + +Next lecture we'll look-- + +Yeah? + +Thank you. + +Question. + +I love questions. + +AUDIENCE: Going back to the +digraph, what makes the graph + +more specialized? + +PROFESSOR: What makes-- + +AUDIENCE: The graph +more specialized? + +PROFESSOR: Good question. + +The question is, what makes the +graph more specialized? + +What we'll see here when we look +at graph, it's not a very + +efficient implementation, but +every time you add an edge, I + +add an edge in the reverse +direction. + +Because if you can get from node +A to node B you can get + +from node B to node A. So I've +removed the possibility that + +you have, say, one-way +streets in the graph. + +And therefore it's +a specialization. + +There are things I can not do +with graphs that I can do with + +digraphs, but anything I can do +with a graph I can do with + +the digraph. + +It's more general. + +That make sense? + +That's a great question and +I'm glad you asked it. + +All right. + +Thursday we're going to look at +a bunch of classic problems + +that can be solved using graphs, +and I think that + +should be fun. \ No newline at end of file diff --git a/Usm7cWtAbRY.txt b/Usm7cWtAbRY.txt new file mode 100644 index 0000000000000000000000000000000000000000..e6a5ddec2e65edbe0540a06aeac234cd303248fe --- /dev/null +++ b/Usm7cWtAbRY.txt @@ -0,0 +1,2108 @@ +The following +content is provided + +under a Creative +Commons license. + +Your support will help MIT +OpenCourseWare continue + +to offer high-quality +educational resources for free. + +To make a donation or +view additional materials + +from hundreds of MIT courses, +visit MIT OpenCourseWare + +at ocw.mit.edu. + +PROFESSOR: Welcome back. + +Today, we will do two problems +involving many oscillators, + +or at least several oscillators, +coupled to each other. + +Now, you will not be surprised, +from past experience, + +that in the situation +with several oscillators, + +we are going to end up with +many equations and a lot + +of grindy, tough +solving of equations. + +Already, with a single +harmonic oscillator, + +for example, with +damping, the equations + +have been pretty horrendous. + +Now, we considered a +couple of oscillators + +with all the details, with +damping, driven, et cetera, + +and it really +becomes complicated. + +Now, what we are +trying to do by doing + +problems is to get a feel, +an understanding what goes on + +in a given situation, so one +wants to focus on new features + +and try to simplify +the mathematics as + +much as possible. + +And so in the problems +are we doing now, + +I am intentionally making them +even more ideal than before. + +Consider the first problem. + +Here is a highly +idealized system + +which has 3 degrees of freedom. + +What we have is we have a single +mass, 2m, two identical springs + +attached to two +masses, each of mass m. + +This is completely idealized. + +We are assuming +there's no friction, + +that these springs +are ideal springs. + +In other words, +they're massless, + +obey Hooke's laws +with constant k. + +We are assuming the +system is constrained, + +so it can only move +in one direction, + +it can't move up and down +or in or out from the board. + +So as I say, it's an +idealized situation. + +And the question we want to +answer is, for such a system, + +what are the normal +mode frequencies? + +And you know from lectures +given by Professor Walter Lewin + +that when you have coupled +oscillators, in this case, 3, + +all right, one finds that there +are very special oscillations, + +which we call normal mode +oscillations, in which + +every part of the +system is oscillating + +with the same +frequency and phase. + +So first, we want to find +out for this system, what + +are those three normal +mode frequencies? + +And secondly, suppose +I take this system, + +place these masses at some +arbitrary positions, some + +maybe even moving, and +let go, how would I + +predict where each mass +would be at some later time? + +So those are the +two questions I want + +to answer today +for this problem. + +Now, in general, coupled +oscillator problems + +are quite difficult. + +But there are +situations in which + +one can use logic +alone, well, logic + +and our understanding +of coupled oscillators, + +to do most of the +solution by hand-waving + +and not do any calculations. + +In this first example I'm +doing in this problem, + +since the system has +a lot of symmetry, + +I know from experience +that under those conditions + +it might be possible to solve +this, as I say, by logic alone + +and our understanding +of coupled oscillators. + +So the issue is, +can I guess what + +will be the motion +in the normal modes? + +And the answer is, actually, +if you stop and think + +for a second, at +least the first two + +modes you can figure +out rather easily. + +So here I'm showing +you schematically + +what would be one of the +modes of oscillation, + +one of the normal modes. + +Imagine that I first +hold this mass fixed + +and I displace these +symmetrically, one + +to the right, one to +the left, and I let go. + +What you will find +is, by symmetry, + +this spring will always be +stretched by the same amount + +as this is compressed, and +so the force on this mass + +will be 0. + +This spring will be pushing this +mass exactly by the same amount + +as this one will be +pulling it and vice versa. + +So there will never be any +net force on this mass, + +and so they'll stay put. + +And these two will now behave +as a simple harmonic oscillator + +consisting of a spring attached +to a fixed wall and the mass m. + +So that's what this +one will be doing, + +and that's what +this will be doing. + +It will be out of +phase by 180 degrees. + +Or what one normally +says, it'll be in phase + +but the amplitude will +be minus the other one. + +This, by now, you've +had enough experience + +and I've done it here +before, I can just + +write what will be that +frequency of oscillation + +here, as we've seen many times. + +And, by the way, throughout +my solving the problems here, + +I do not differentiate frequency +and angular frequency, that you + +can see which I'm talking about +is whether I'm using omega + +or F. Omega is the +angular frequency, + +and there's just a fact +of 2 pi between the two. + +But I'll use, interchangeably, +I'll call this frequency. + +So this frequency of one of +the normal modes is just k/m. + +So we found one +normal mode frequency. + +Let's look for another one. + +We stare at this and we see, +sure, there is another one. + +Another one is where I take, +simply, these two masses + +and simultaneously pull +them out, in this mass, + +away and let go. + +Effectively, these two +will look like that. + +It's as if I had a mass of +2m attached to a mass of 2m + +by two springs, each +of spring constant k. + +And as I pull this back, this +will oscillate like this. + +Everything, both this +mass and this mass, + +will be oscillating with the +same frequency, same phase, + +although there's +this minus sign. + +I can always replace the +180-degree phase shift + +by saying the +amplitude is minus. + +So those are +identical statements. + +So you have these two masses +oscillating like that. + +OK? + +By the way, I've said +that in the normal mode + +I want everything to move +with the same frequency. + +Some of you may argue, hold on. + +Did I cheat on you? + +Here, this mass is +not oscillating. + +So am I contradicting myself? + +And the answer is no. + +It's a diabolical answer. + +But I'll say, no, +this is oscillating + +with this frequency, +but with 0 amplitude. + +And you can't tell +me that I'm wrong. + +It's not moving because +the amplitude is 0, + +but it is oscillating +with the same frequency. + +So now, what is the frequency +of this oscillation? + +Again, I can do it in my head. + +I can imagine that the middle +of this spring is not moving. + +And so this mass is a half +a length of the spring + +and a mass 2 attached +to it oscillating, + +and I can calculate +the frequency + +of oscillation of that. + +Or if you prefer, I +can do the following. + +I can move this mass out a +distance dx and this one dx + +to the other side +and calculate what + +will be the restoring force. + +Well, now each one has +a spring constant k. + +There is two of +them, so that's 2k. + +Although this mass has been +moved by dx, this by dx, + +the springs have been extended +by twice dx, so it's 2 dx. + +So that's the total +restoring force + +by Hooke's law, which +is equal minus 4k dx. + +All right? + +And so this will behave +like a single mass, + +like this system, a single +mass with a single spring + +where the spring has +a spring constant 4k. + +The mass is 2m. + +And so the angular frequency, or +frequency of this mode is 2k/m. + +So we've found two of them. + +Now, we know from our studies +of coupled oscillators + +that for a system of +3 degrees of freedom, + +so it would be three masses, +there are three normal modes. + +What is the third normal mode? + +And I intentionally +did not write it + +down here because I wanted +you for a second to think. + +Well, how else can +this system move such + +that every mass is moving in +phase with the same frequency? + +All right? + +And I tell you, +when I first saw it, + +it took me a long +time to figure out, + +and most people don't find it. + +And yet the answer +is extremely simple. + +This answer is there is +one more normal mode. + +It is one of almost infinite +amplitude, but 0 frequency. + +Just the opposite to here, +where this was 0 amplitude, OK, + +and the angular frequency +doesn't even matter. + +Here it has very large +amplitude, infinite in fact, + +but 0 frequency. + +What does such motion look +like at any instant of time? + +It's moving with +the same velocity. + +So if I take and if I +consider the motion where + +each one of these is moving +uniformly to the right + +with a constant +velocity, that is + +a normal mode with 0 frequency. + +So the last one is +omega C is equal to 0. + +OK? + +So we have now found +the three normal modes. + +OK. + +All right. + +Now that I've got a piece +of chalk, let's continue. + +So we've answered the first +part of the question, what + +are the normal mode +frequencies of the system? + +And I found you those +three normal modes. + +Now, the next question +we want to answer + +is, if, at any given +instant of time, + +I know the positions and the +velocities of the three masses, + +can I predict what +will happen at the end? + +That's equivalent +of saying, can I + +write equations for the +positions of the masses + +as a function of time? + +For that I need to define for +myself a coordinate system. + +So I'll say those are +those three masses. + +All the motion is +along the x direction, + +so there's just one variable, +one variable for each mass, x. + +So the position +of the first mass + +I'll call x1, position +of the second mass x2, + +and of the third is x3. + +And the origin of +coordinates I will + +take to be through the +center of each mass + +at a time when these +are in equilibrium. + +In other words, the spring +is unstretched, et cetera. + +OK. + +So I can now, using the +information we've obtained, + +write down the description +of each mass in each mode. + +So in mode A, I know that +the x1 is 0 all the time. + +It's not moving, OK? + +Now, in a normal mode, that's +what we mean by a normal mode, + +each mass is moving +with the same frequency + +and the same phase, +and it's oscillating. + +So there will be some sinusoidal +function of the mode frequency + +t plus this phase times +some arbitrary amplitude. + +The other one, the +last one, will also + +be oscillating in +the normal mode, + +so everything will be the same. + +It will be cosine of +omega A t plus phi + +A with some other amplitude. + +But from our analysis +here, we know + +that these two are +not both arbitrary. + +Because we said that +in the normal mode, + +it was the case where the +2m mass was stationary, + +but these were going like this. + +That was the first mode. + +So whenever this one was going +to the right a distance A, + +this one was going to +the left a distance A. + +So the overall +normalization is arbitrary. + +It can be anything. + +But these are not +independent of the other, + +because we discovered +that in that mode, + +this was the frequency, +and the amplitudes were + +opposite to each other. + +So this describes the +situation for this system + +if it's oscillating in +the first normal mode. + +It's the most general +description of that. + +Next, I will +describe what it will + +do in the second normal mode. + +And now I can go much quicker. + +This time, it'll have +the second normal mode + +frequency, different phase. + +But these have to be the same +because all of these masses + +are moving in the same normal +mode, same normal frequency. + +These amplitudes, +overall, it's arbitrary. + +I can make it anything. + +It'll satisfy the equations. + +But I know that in the +second normal mode, + +this one is moving in that +direction and those two + +in the opposite direction +with the same magnitude. + +So these two have to have +the same size and magnitude, + +but this has to be opposite. + +So this describes the +motion in the second mode. + +And finally, in the +third normal mode, + +we said that it was 0 frequency. + +All right? + +And all that was +happening, the three masses + +were moving with +uniform velocity. + +So the positions +will be some constant + +plus the velocity +of that system. + +So this describes the +system in the third mode, + +and these are the other two. + +Now, I know that, in general, +each one of these masses + +can move in a superposition +of the normal modes. + +So the most general +expression for x1 of t + +has to be of the form which is +the sum of its possible motion + +in each of the modes. + +So x1, so this is +the mass 2m, will + +have possible motion in +the first mode, which is 0. + +All right? + +So I'll write 0 plus B times +cosine omega B t plus phi + +B, all right, plus +C plus v. So that + +will be the most general +description of the motion + +of the big mass, the 2m one. + +The B is arbitrary, +this phase is arbitrary, + +this is arbitrary, and +v. Those quantities + +will be determined by +the initial conditions. + +Well, how about x2? + +Well, I know that if x1 is +0, x2 is A cosine omega A t + +plus phi A. When the x1 is this, +then x2 is minus B cosine omega + +B t plus phi B, OK, +and plus C plus v. OK? + +And finally, x3 of t, +again now just following + +the same pattern, this is +minus A cosine omega A t + +plus phi A. This one is +minus B cosine omega B + +t plus phi B plus C plus v. + +And I'm almost home. + +I have described the +motion of each one. + +For each particle, +it is oscillating + +in a superposition +of its normal modes. + +And the amplitudes are +arbitrary within the constraint + +that the ratios between +them is determined + +by the constraints +of the system. + +So now the question is, +can I predict the future? + +Well, in order to +predict the future, + +say, where will +particle 3 be at time t? + +I need to know the value of +these arbitrary constants. + +Omega is not an +arbitrary constant. + +We found it. + +Omega A is here. + +OK? + +This is arbitrary, this is +arbitrary, this, and that. + +So there are six +arbitrary constants. + +How do I find them? + +They are determined by +the initial conditions. + +And you know, +fortunately, or else it + +would mean we've made a mistake, +we have three conditions. + +At the beginning, +someone has to tell me + +where each mass was, the +location, and with what + +velocity is it +moving at that time. + +So I can write these +three equations at, say, + +with t equals 0, at t +equals 0, and equate this + +to the position of x1 of t +equals 0, wherever it is. + +When the t is 0, I make it +equal to the position of x2 at t + +equals 0. + +When t is 0, this tells me has +to be equal to where x3 is. + +That's three equations. + +I can differentiate +each with respect + +to time to get the +velocities, and likewise, + +get three more equations. + +So I'm going to end up with +six algebraic equations. + +And you, as well as +I, know that if we + +have six algebraic equations, +I can solve for six unknowns. + +And that will give me +those six unknowns. + +So once I've used the +initial conditions, + +I can then find these +arbitrary constants. + +They're no longer arbitrary +for a specific situation. + +And I can predict the future, +what will happen in this case. + +OK? + +So that's the way one +would solve a problem when + +you are lucky +enough that there is + +sufficient symmetry in +the original situation + +so you can guess +the normal modes. + +The next problem I'll do, I will +do one where you cannot guess + +the normal modes. + +What do you do under +those circumstances? + +And you won't be +surprised that it's + +going to be mathematically much, +much harder, but conceptually + +no harder. + +So now we'll move +to the next problem. + +Here it is. + +But in order to be able +to do this problem, + +I need more board space. + +So we're going to erase the +boards and continue from there. + +OK. + +So now let's go and +do the second problem. + +And it's going to be a +problem with no symmetry, + +so we can't guess the +answer like we did before. + +And I'll tell you +what I decided to do. + +You remember +Professor Walter Lewin + +in his lectures discussed +a double pendulum. + +In other words, +a situation where + +you had a string, a mass, +another string, and mass. + +He gave you the answer, +but he didn't prove it. + +He said it's hard and +lengthy, et cetera. + +And I thought that would +be a perfect example + +to do here from +first principles. + +So let me just +describe in detail + +the problem we're +trying to solve. + +What we have is, again, +an idealized situation. + +We have a simple pendulum +with a string of length L, + +attached to it a mass m. + +Attached to this mass at one +end is another string of length + +L to another mass m. + +We'll again idealize +the situation. + +So the assumptions +we are making, + +that this string and this string +is massless, which, by the way, + +is equivalent to saying that +it's taut and straight all + +the time. + +You can think about +that for yourself. + +Next, these masses +are point masses. + +And we're assuming no friction. + +Furthermore, as we've +done in the past, + +we'll assume that +all displacements + +when this is oscillating, at all +times the angle that the string + +makes with the vertical is +always such that we can ignore + +the difference between +a sine theta, theta, + +or [INAUDIBLE] can make the +assumption that cosine theta is + +0. + +By the way, the fact that +we'll make this assumption + +is equivalent to +saying that we'll + +ignore vertical motion +of these masses. + +The motion is sufficiently +small that vertically the masses + +are not moving. + +We can assume the acceleration +vertically is 0, et cetera. + +OK? + +This is in the vertical plane. + +Gravity is down. + +OK? + +And what we are trying +to derive for this, + +predict what are the normal +mode frequencies of this. + +And once we do +that, of course, we + +can use the same kind of +technique as we did before. + +Once we've managed to +find the normal modes + +and the frequencies, +we can always + +write the most +general expression. + +And then using the boundary +conditions, initial conditions, + +predict what this will +do as a function of time. + +OK, so let's get going. + +OK. + +Now, we are not guessing. + +We are not using logic. + +We are following the +kind of prescription + +I've told you in the past. + +This is our description +of the situation. + +And all the new words +and ordinary language, we + +must now translate +it into mathematics. + +We've got to +describe this problem + +in terms of +mathematical equations. + +So step one is we +redraw this and define + +some coordinate system. + +So we will say that the +angle this first string makes + +with respect to the +vertical is theta 1. + +This angle the second +string makes with respect + +to the vertical is theta 2. + +We will take the vertical +through this pivot + +here as our origin +of coordinate x. + +x equals 0 here, +is defined here. + +From the point of your +motion of the masses, + +it's a one-dimensional problem. + +The masses only move +along the x-axis. + +So we'll define +this distance as x1, + +and we'll define +this distance as x2. + +Now we have to use the laws of +physics, Newtonian mechanics, + +to derive the equations of +motion for the two masses. + +So I draw a force diagram +separately for the two masses. + +So the mass is there, what +forces act on that mass? + +Well, I have to look at the mass +and see what's attached to it. + +There is a string +here attached to it. + +It's taut, so there +will be a tension in it. + +So along this string, +there will be tension T1, + +which will exert a force +T1 along this string. + +This string is +attached to that mass. + +It has a tension, so it's +pulling on this mass. + +That tension I call +T2, so there will + +be a force along +that direction T2. + +This sits in a +gravitational field. + +Gravity acts on this mass. + +There is a force downwards +due to gravity, Fg. + +The sum of these forces, +by Newton's laws, + +must equal to the mass +times the acceleration. + +That acceleration, in this +approximation that is not + +moving up, is +horizontally, and it's + +the second derivative of x1. + +Similarly, for the second mass, +again, I'll go now faster. + +There is this mass +m, and this tension + +exerts a force here of T2 +and the gravity on it Fg. + +The only subtlety +is, why did I say + +this force is equal +to that force? + +Think about it for a second. + +Why should the two +forces be equal? + +Why is the tension at both +ends of the string equal? + +And the answer is, +actually, a subtle one. + +It's equal because we made the +assumption that the string has + +no mass, and there can be no net +force on an object of 0 mass. + +Because if there was, that +object would disappear, + +would have an +infinite acceleration. + +So if you treat the +string as a mass, + +there cannot be net force on it. + +And so the force of +each of these masses + +must be pulling on this string +with exactly the same force + +equal and opposite. + +OK? + +And we're using the third +law to equate those forces. + +So the net result is this +T2 is the same as that, + +but in opposite direction, +and this is the mass of that. + +OK. + +So these are the force diagrams. + +Using now Newton's +laws of motion, + +I can translate this +into equations of motion. + +So let me consider +the horizontal motion + +of each mass separately. + +First this mass, and so +its mass times acceleration + +is equal to the +horizontal force of T2. + +And remember that this +angle here is theta 2. + +And we see that the +force due to T2, + +and there's a T2 sine theta 2. + +And the force due to T1 +is minus T1 sine theta 1 + +because it's in the +opposite direction. + +For this, the only +horizontal component + +is the force horizontal +component of T2. + +And x2 double dot is equal +to minus T2 sine theta 2. + +OK, that's horizontal motion. + +Applying Newton's laws of +motion to the vertical motion, + +we said that, because cosine +theta is 0 or approximately 0, + +the masses are not +moving up and down. + +There's no acceleration +of the masses. + +So the vertical acceleration +of the first mass + +is 0 must be equal to the +vertical component of T1, which + +is T1 cosine theta 1, minus +the vertical component of this, + +which is minus T2 +cosine theta 2 minus mg. + +All right. + +Similarly for the second +mass, it's 0 is equal to this. + +0 must equal to the +vertical component + +of T1 minus the +vertical component of T2 + +minus the force of gravity down. + +And similarly for +the second mass, + +we know that vertically +the acceleration is 0. + +That must be equal to the +vertical component of T2 + +minus the gravitational +force pulling down. + +Now I can make use of what we +made the assumption-- oops, + +I see there is an error. + +If you were in this +room, I'm sure you + +would have corrected me. + +For very small angles, +the sine of an angle + +is approximately +equal to the angle. + +But for small angles, +the cosine is 1. + +This is an error, and +I apologize for that. + +But that's the +approximation we are making. + +And it is this +approximation which + +is equivalent to saying that we +can ignore the vertical motion. + +All right. + +So with the assumption +that the cosines are all 1, + +I can, from these two +equations, I clearly + +derive that T2 must equal to +mg, and T1 equals twice mg. + +Actually, it makes sense. + +Imagine this is hanging +completely vertically. + +Obviously, this string, the +upper part of the string, + +is supporting not only +this mass but also that. + +It's supporting 2m masses, +while this string is only + +supporting 1. + +So that's consistent +with what we see, + +that the top string has twice +the tension and the lower + +one half the tension. + +Having determined T1 +and T2, we can now + +go back into our equation, +replace the T1 and T2. + +We also can replace-- +we know what + +sine theta 1 and +sine theta 2 are. + +We can replace those. + +And we end up-- +the two equations + +of motions are written here. + +All right? + +So here is the equation +of motion for x1. + +And the second one, the +equation for motion of x2, + +is written here. + +OK? + +So these are the +equations of motion, + +all right, which +we have to solve. + +Now, to simplify the algebra, +let me define the quantity g/l + +by omega squared over 2. + +And you'll recognize this. + +This is not [INAUDIBLE]. + +I'm using that terminology. + +This is the frequency +of oscillation + +of a mass on a +string of length l. + +All right? + +So here are our two differential +equations, the two equations + +of motion, one for +x1 and one for x2. + +When we had one mass, +one harmonic oscillator, + +we had a single second-order +differential equation. + +We now have two +masses, so we have + +two second-order +differential equations. + +These are it. + +They are coupled +differential equations. + +You see, the derivatives of x1 +is related both to x1 and x2. + +The second derivative of x2 is +related both to x1 and to x2. + +So these are two coupled +differential equations. + +OK? + +This is the end of step 1. + +What we succeeded +in, we've translated + +the physical situation +into mathematics. + +These two second-order +differential equations + +describe exactly that +idealized situation we had. + +So if I now want to +answer the question, what + +will be the motion +of those masses, + +I have to go into the +world of mathematics. + +I have to solve these equations. + +And life is not +as easy as it was + +for a single second-order +differential equation. + +It's more complicated. + +But here I will use +my general knowledge + +of what happens when you +have coupled oscillators. + +I know that the general +solution of coupled oscillations + +is a superposition +of normal modes. + +Here I have 2 +degrees of freedom, + +two second-order +differential equations. + +There will be two normal modes. + +If I succeed in +finding them, I will + +have found the most general +solution to this problem, + +because it will be the sum +of the two normal modes. + +So I will now do it by trial. + +In a normal mode, +we know that x1 + +will be oscillating +with a single frequency + +omega, some phase phi, +some amplitude A1. + +This will be a solution +to these equations. + +If this is a solution +to those equations, + +the other mass must +also be oscillating + +in the same normal mode, +meaning with the same frequency + +and same phase. + +It'll have some +arbitrary amplitude. + +So I don't know what A1 is, +and I don't know what omega is. + +I don't know what phi is. + +But I know that the +solutions to these equations + +must be of this form. + +OK? + +So let me now try to find +these various constants. + +Well, if this and that +satisfies these equations-- + +and it has to because +that's what it's saying, + +these are the solutions +of those equations-- + +then I can take these, x1 and +x2, plug it into this equation. + +In other words, calculate +the second derivative + +of x1, et cetera, +calculate second, + +and I'll end up +with two equations. + +OK? + +So I won't bother to go +in great detail here. + +But just to start off +with, x1 double dot, + +I have to differentiate +A1 cosine omega t twice. + +So I get minus omega squared A1 +times cosine omega t plus phi. + +If I take the next term, I get +this, and the third term that. + +And in each case, if +you notice, since it'll + +be multiplied by the +same cosine function, + +I've just canceled in my head +the cosine function there. + +All right? + +Just saving time. + +Similarly, next equation, +I end up with this. + +So if my guessed functions, +and I'm returning to this, + +if these two satisfy +those equations, + +then here these algebraic +equations must be satisfied. + +But you'll notice +something interesting. + +If I take the first +of these equations, + +it boils down to A1 times +this quantity plus A2 + +to [? then ?] this +quantity equal to 0. + +And the second equation +boils down to this. + +If this is true, then +this must be true. + +It's A1 divided by A2 +has to be equal to that. + +If this is true, +then A1 divided by A2 + +has got to be equal to this. + +That means that this +has to be equal to that, + +or else I have an inconsistency. + +So what I have found is +that, in general, my guess + +is not a good one. + +In general, these +equations would not + +satisfy my second-order +differential equations. + +There is only under very +special circumstances + +that they do +satisfy it, and that + +is if this is equal to that. + +In general, they +will not be equal. + +So under what conditions +will these be equal? + +Well, let me force them. + +Let me say this is +equal to that and see + +what it means for omega. + +I originally took omega +to be an unknown quantity. + +What I am now seeing, +that those functions + +would work only for +specific values of omega. + +So I'm going to solve +this equation for omega + +and see for what values of omega +do I get a consistent solution. + +And this is a hard +grind, unfortunately. + +If I take this, +multiply it out, I + +get a quadratic equation +in omega squared. + +If this quadratic +equation is satisfied, + +then all these are +self-consistent. + +All right? + +You know how to solve +a quadratic equation, + +and this is a quadratic +equation in omega squared. + +Omega square will have +to be equal to minus + +this plus or minus the +square root of this, + +4 times this times that, +divided by 2a, right? + +This is the standard +formula for the solution + +of a quadratic equation. + +And there's a plus or minus. + +If I calculate this out, +I get that omega squared + +has to be equal +to 2 plus or minus + +the square root of 2 +times omega 0 squared. + +All right? + +Now, omega 0 squared, earlier +on, I defined to be g/l. + +So omega squared has to be this. + +So let's stop for +a second and think + +and review what we've done. + +We found that our +physical situation + +can be described by these two +coupled differential equations. + +We looked for solutions, which +are normal modes where both x1 + +and x2 is oscillating with +same frequency and phase. + +And we found that it was +possible to find solution + +of this form to these equations +if and only if omega squared + +has one of two possible values. + +I've rewritten them here. + +One is 2 plus root 2 +times g/l, and the other's + +2 minus root 2 g/l. + +With these values, these two +equations satisfies that. + +So what we found is +the two normal modes. + +Since this system consists +of the coupled oscillators, + +in other words, two oscillators +coupled with each other, + +we know there are +two normal modes. + +So these are the normal mode +frequencies in this situation. + +And by the way, I'm +delighted to see + +that, if you remember Professor +Walter Lewin's lectures, + +he actually quoted +these numbers. + +So he was right. + +He did not make a mistake, +as we've just seen. + +OK? + +These are the two +normal mode frequencies. + +Now, how about if +we want to predict + +everything, the +amplitude, et cetera? + +We've got to be careful here +with the logic we've applied. + +For any one of these normal +frequencies, say this one, + +earlier on we found that A1 to +A2 is given by this equation + +or by this equation. + +But for the given +values of omega, + +we found these are +now equivalent. + +And so if you know what +omega is, say omega A, + +one of the normal +modes, this we know. + +It's g/l. + +And this is known. + +So A1/A2, once we fix +omega A, is fixed. + +So these are not two +independent amplitudes. + +So if I go back to here when +we said let's guess a solution, + +and this was an arbitrary +number and this was an arbitrary + +number, now we see +that in a normal mode + +the ratio between them is fixed. + +It depends on the +normal mode frequency. + +But the [? overall ?] +normalization + +is still arbitrary. + +I could make this 10 times +this and 10 times that. + +[? It would still ?] work. + +So back to here, we found one of +the normal mode's frequencies. + +Using the equation +above, it determines + +the value of A1 to A2. + +Taking the other +normal mode frequency + +determines the +ratio of those two + +but not the overall amplitude. + +Not to confuse the two, I +will call this B1 and B2. + +This is the amplitude +of the first mass, + +and this is of the other one. + +The ratio is fixed, determined +by the value of omega B. + +But the overall +amplitude is not. + +So now we have ended up +in the same situation + +we were in our three masses, +where, if you remember, + +I started by guessing +the normal modes + +and guessing the +relative amplitudes. + +And with that information alone +and the initial conditions, + +I could predict +what will happen. + +I could now repeat that here. + +But to save time, I think +you can do that for yourself. + +For each, you can write +now a single equation + +saying what a given mass will do +as the sum of two normal modes, + +where you know the frequency +of them and the amplitudes. + +And you have to remember +that for the two masses, + +the ratio of the amplitudes +in each normal mode + +have to be fixed given +by what we've done here. + +And therefore, you can +get the single equation + +for each mass, one for one +mass, one for the other. + +Which will tell you what +they will do in the future + +if you know what they're +doing initially, for example, + +the initial conditions, +that you can solve + +to get the final predicted +position of each mass. + +So that's as much +as I was hoping + +to do today on +coupled oscillators. + +And we'll continue +next time on situations + +with many, many more +degrees of freedom. + +Thank you. \ No newline at end of file diff --git a/XTUe-VMvRis.txt b/XTUe-VMvRis.txt new file mode 100644 index 0000000000000000000000000000000000000000..3a3b4591274d57a9d410efc2ce7fcae5e7dc1384 --- /dev/null +++ b/XTUe-VMvRis.txt @@ -0,0 +1,587 @@ +align:start position:0% + +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +hi dude what are you up to I'm picking a + + align:start position:0% +hi dude what are you up to I'm picking a + + + align:start position:0% +hi dude what are you up to I'm picking a +promoter to use in buddy I need a + + align:start position:0% +promoter to use in buddy I need a + + + align:start position:0% +promoter to use in buddy I need a +promoter that is always on that will + + align:start position:0% +promoter that is always on that will + + + align:start position:0% +promoter that is always on that will +make buddy be red so why are you poking + + align:start position:0% +make buddy be red so why are you poking + + + align:start position:0% +make buddy be red so why are you poking +at the computer screen well how else do + + align:start position:0% +at the computer screen well how else do + + + align:start position:0% +at the computer screen well how else do +I pick one I don't know which one to use + + align:start position:0% +I pick one I don't know which one to use + + + align:start position:0% +I pick one I don't know which one to use +so I figured I'd leave it to chance to + + align:start position:0% +so I figured I'd leave it to chance to + + + align:start position:0% +so I figured I'd leave it to chance to +decide well why don't you use some of + + align:start position:0% +decide well why don't you use some of + + + align:start position:0% +decide well why don't you use some of +the promoter characterization data + + align:start position:0% +the promoter characterization data + + + align:start position:0% +the promoter characterization data +available on the registry of standard + + align:start position:0% +available on the registry of standard + + + align:start position:0% +available on the registry of standard +biological parts to the side what is + + align:start position:0% +biological parts to the side what is + + + align:start position:0% +biological parts to the side what is +promoter measurement data hi dude hi + + align:start position:0% +promoter measurement data hi dude hi + + + align:start position:0% +promoter measurement data hi dude hi +Izzy sounds like you two are having an + + align:start position:0% +Izzy sounds like you two are having an + + + align:start position:0% +Izzy sounds like you two are having an +interesting conversation yeah I was just + + align:start position:0% +interesting conversation yeah I was just + + + align:start position:0% +interesting conversation yeah I was just +about to tell Dude how to use the + + align:start position:0% +about to tell Dude how to use the + + + align:start position:0% +about to tell Dude how to use the +promoter measurement data to pick the + + align:start position:0% +promoter measurement data to pick the + + + align:start position:0% +promoter measurement data to pick the +right promoter for body well before you + + align:start position:0% +right promoter for body well before you + + + align:start position:0% +right promoter for body well before you +get into those details it might be worth + + align:start position:0% +get into those details it might be worth + + + align:start position:0% +get into those details it might be worth +chatting a bit about measurement in + + align:start position:0% +chatting a bit about measurement in + + + align:start position:0% +chatting a bit about measurement in +general why synthetic biologists measure + + align:start position:0% +general why synthetic biologists measure + + + align:start position:0% +general why synthetic biologists measure +part function what measurements they + + align:start position:0% +part function what measurements they + + + align:start position:0% +part function what measurements they +make and how they do the measurements + + align:start position:0% +make and how they do the measurements + + + align:start position:0% +make and how they do the measurements +before getting into the details of the + + align:start position:0% +before getting into the details of the + + + align:start position:0% +before getting into the details of the +data itself that's true why don't we + + align:start position:0% +data itself that's true why don't we + + + align:start position:0% +data itself that's true why don't we +take a walk + + align:start position:0% +take a walk + + + align:start position:0% +take a walk +get some fresh air while we talk + + align:start position:0% +get some fresh air while we talk + + + align:start position:0% +get some fresh air while we talk +measurement is a key aspect of Science + + align:start position:0% +measurement is a key aspect of Science + + + align:start position:0% +measurement is a key aspect of Science +and Engineering it lets you quantify the + + align:start position:0% +and Engineering it lets you quantify the + + + align:start position:0% +and Engineering it lets you quantify the +function of a part or component and + + align:start position:0% +function of a part or component and + + + align:start position:0% +function of a part or component and +compare its function to that of others + + align:start position:0% +compare its function to that of others + + + align:start position:0% +compare its function to that of others +unfortunately in synthetic biology we're + + align:start position:0% +unfortunately in synthetic biology we're + + + align:start position:0% +unfortunately in synthetic biology we're +still figuring out what are the most + + align:start position:0% +still figuring out what are the most + + + align:start position:0% +still figuring out what are the most +useful measurements to make for genetic + + align:start position:0% +useful measurements to make for genetic + + + align:start position:0% +useful measurements to make for genetic +parts and devices what do you mean why + + align:start position:0% +parts and devices what do you mean why + + + align:start position:0% +parts and devices what do you mean why +don't we just measure everything for + + align:start position:0% +don't we just measure everything for + + + align:start position:0% +don't we just measure everything for +every part well that can pretty quickly + + align:start position:0% +every part well that can pretty quickly + + + align:start position:0% +every part well that can pretty quickly +lead both to a lot of waste of time in + + align:start position:0% +lead both to a lot of waste of time in + + + align:start position:0% +lead both to a lot of waste of time in +making measurements that don't matter as + + align:start position:0% +making measurements that don't matter as + + + align:start position:0% +making measurements that don't matter as +well as an overwhelming in amount of + + align:start position:0% +well as an overwhelming in amount of + + + align:start position:0% +well as an overwhelming in amount of +information ideally we'd like to be able + + align:start position:0% +information ideally we'd like to be able + + + align:start position:0% +information ideally we'd like to be able +to only measure those characteristics of + + align:start position:0% +to only measure those characteristics of + + + align:start position:0% +to only measure those characteristics of +a part that you need to know in order to + + align:start position:0% +a part that you need to know in order to + + + align:start position:0% +a part that you need to know in order to +decide whether the part will work in + + align:start position:0% +decide whether the part will work in + + + align:start position:0% +decide whether the part will work in +your system of interest for example when + + align:start position:0% +your system of interest for example when + + + align:start position:0% +your system of interest for example when +I bought a computer recently I care + + align:start position:0% +I bought a computer recently I care + + + align:start position:0% +I bought a computer recently I care +about how big the hard drive was and how + + align:start position:0% +about how big the hard drive was and how + + + align:start position:0% +about how big the hard drive was and how +much memory it had because those were + + align:start position:0% +much memory it had because those were + + + align:start position:0% +much memory it had because those were +two performance metrics that I could use + + align:start position:0% +two performance metrics that I could use + + + align:start position:0% +two performance metrics that I could use +to figure out whether the computer would + + align:start position:0% +to figure out whether the computer would + + + align:start position:0% +to figure out whether the computer would +be sufficient for my needs well in the + + align:start position:0% +be sufficient for my needs well in the + + + align:start position:0% +be sufficient for my needs well in the +case of buddy I just need to know which + + align:start position:0% +case of buddy I just need to know which + + + align:start position:0% +case of buddy I just need to know which +promoter to use that will make him red + + align:start position:0% +promoter to use that will make him red + + + align:start position:0% +promoter to use that will make him red +but how red do you want buddy to be + + align:start position:0% +but how red do you want buddy to be + + + align:start position:0% +but how red do you want buddy to be +should body be pink red or dark red to + + align:start position:0% +should body be pink red or dark red to + + + align:start position:0% +should body be pink red or dark red to +make decisions like that you might need + + align:start position:0% +make decisions like that you might need + + + align:start position:0% +make decisions like that you might need +to know a bit more about how strong the + + align:start position:0% +to know a bit more about how strong the + + + align:start position:0% +to know a bit more about how strong the +promoter is exactly another measurement + + align:start position:0% +promoter is exactly another measurement + + + align:start position:0% +promoter is exactly another measurement +you might care about is how long the + + align:start position:0% +you might care about is how long the + + + align:start position:0% +you might care about is how long the +part Works before it breaks genetic + + align:start position:0% +part Works before it breaks genetic + + + align:start position:0% +part Works before it breaks genetic +Parts can break as buddy grows and + + align:start position:0% +Parts can break as buddy grows and + + + align:start position:0% +Parts can break as buddy grows and +divides for example mutations or + + align:start position:0% +divides for example mutations or + + + align:start position:0% +divides for example mutations or +deletions can happen that interfere with + + align:start position:0% +deletions can happen that interfere with + + + align:start position:0% +deletions can happen that interfere with +part function so depending on how long + + align:start position:0% +part function so depending on how long + + + align:start position:0% +part function so depending on how long +you expect buddy to stick around you + + align:start position:0% +you expect buddy to stick around you + + + align:start position:0% +you expect buddy to stick around you +might choose promoters that are more or + + align:start position:0% +might choose promoters that are more or + + + align:start position:0% +might choose promoters that are more or +less genetically stable wao I had no + + align:start position:0% +less genetically stable wao I had no + + + align:start position:0% +less genetically stable wao I had no +idea measuring part function could be so + + align:start position:0% +idea measuring part function could be so + + + align:start position:0% +idea measuring part function could be so +complicated well I think I am going to + + align:start position:0% +complicated well I think I am going to + + + align:start position:0% +complicated well I think I am going to +find myself a strong promoter from the + + align:start position:0% +find myself a strong promoter from the + + + align:start position:0% +find myself a strong promoter from the +registry I've decided that I want buddy + + align:start position:0% +registry I've decided that I want buddy + + + align:start position:0% +registry I've decided that I want buddy +to be very dark red have + + align:start position:0% +to be very dark red have + + + align:start position:0% +to be very dark red have +fun Jin \ No newline at end of file diff --git a/XxvD0Yh9qCM.txt b/XxvD0Yh9qCM.txt new file mode 100644 index 0000000000000000000000000000000000000000..ab9b1b3fc3d3ed81f6d09c370a3a8f9c2e62a455 --- /dev/null +++ b/XxvD0Yh9qCM.txt @@ -0,0 +1,2125 @@ +The following content is +provided under a Creative + +Commons license. + +Your support will help MIT +OpenCourseWare continue to + +offer high quality educational +resources for free. + +To make a donation or view +additional materials from + +hundreds of MIT courses, visit +MIT OpenCourseWare at + +ocw.mit.edu. + +PROFESSOR: OK, so we're going +to leave off where we were + +last time talking +about buffers. + +And I'm a big fan of buffers, +actually, and buffers are + +extremely useful in my research +because they keep the + +p h of things constant. + +So if you're going to do any +kind of biology research or + +biochemistry research, you need +to know about buffers. + +And as I'll mentioned later, +also your body needs to be + +buffered appropriately, you +don't want a large changes in + +p h in your body or things +won't function properly. + +So buffering is very +important. + +So let's go over buffers. + +So if we talk about an acid +buffer, that's something + +that's buffering on the acidic +side of the p h range. + +And in that, you want to have +play on both sides. + +So if you have a strong acid, it +can be neutralized, the p h + +stays the same. + +If you had a strong base, that +would be neutralized so the p + +h stays the same. + +So what happens, you have to +have an acid and its conjugate + +base in the mixture to +have a good buffer. + +So what the weak acid is going +to do is it will transfer + +protons or hydrogen ions to +hydroxide ions that are + +supplied by the strong base to +neutralize that strong base + +that was added. + +So you need to have an acid in +there that's capable of giving + +up a proton to neutralize the +hydroxide ion that was added. + +You also need to have +a conjugate base. + +The conjugate base is going to +accept protons if an acid is + +added, thereby neutralizing the +effect of that added acid. + +So again, you need a weak acid +and its conjugate base, you + +need both to have +a good buffer. + +So I've been talking about weak +acids and weak conjugate + +bases, so why would a strong +acid and the salt of its + +conjugate base not make +a good buffer? + +What do strong acids do? + +They dissociate almost +completely, and that's not + +going to do you any good. + +You want to be able to shift +that equation both directions. + +So a strong acid goes to +completion is going to drive + +it to the right, and for a good +buffer you want to be + +able to switch things around +that if you add a strong acid, + +then you neutralize that, you +add a strong base, you + +neutralize it. + +So you need the conjugate to be +effective as a base, and a + +strong acid has an ineffective +conjugate base. + +It's not good as a base at +all, so that won't work. + +So buffers are made up of weak +acids and their conjugate + +bases, or weak bases and +their conjugate acids. + +They need to be in the +weak range or there's + +no buffering capacity. + +So let's look at a base +buffer example. + +The only difference here is that +a basic buffer is going + +to buffer on the basic +end of the p h range. + +So here's an equation. + +We have a base in water forming +a conjugate of that + +weak base and hydroxide ions. + +So let's think about +what happens if a + +strong acid is added. + +Well if a strong acid is added, +then this base, n h 3, + +can accept protons from the +incoming acid and make more n + +h 4 plus, thereby removing the +strong acid from the solution + +and neutralizing the p h. + +If on the other hand a strong +base is added, n h 4 plus or + +ammonium ions can donate the +proton forming its conjugate + +base in water, and again, the +p h remains about the same. + +So the base and its conjugate +acid can both react, + +neutralizing the p h. + +So in the base buffer acid, a +weak base, b, will accept + +protons supplied by the strong +acid, removing a strong acid + +from the solution. + +The conjugate acid of that weak +base, which again, would + +be a weak acid, can transfer +protons to the hydroxide ions + +added by the strong +base, again, + +neutralizing the effect there. + +So a buffer is a mixture of a +weak acid base conjugate pair + +that will stabilize the p h +serving as a source or a sink + +for the added protons. + +So that's how a buffer works. + +So, I mentioned buffering +is very important. + +It's very important +in your blood. + +Your blood is buffered in +the range of p h 7 . + +35 to 7 . + +45, and you have a buffering +pair and a conjugate acid base + +pair that's in your blood +that does to work. + +So nature has its own buffering +system design to + +keep the p h of your +blood constant. + +Well what happens if the p +h of your blood changes? + +So let me just tell you about +one disease that can change + +the p h of your blood. + +This is from a vitamin B12 +dependent enzyme called + +methylmalonic coa mutase, and +this enzyme is your friend. + +I think that most of you are +excited about the idea of + +having all your fat go to +energy, so you should be all + +fan of this enzyme. + +So it breaks down from fatty +acids -- you get methylmalonyl + +coa, which is converted to +succinyl coa and goes into the + +citric acid cycle. + +But if this step is blocked, +if there's some kind of + +genetic disease associated with +that particular enzyme, + +you get a condition called +methylmalonic aciduria. + +So this is excreted in the body, +it can't be converted to + +the succinyl coa, so it has to +be excreted from the body, and + +it has an acidic p h. + +And so when it's excreted, it +will actually, there's a large + +amount of it, and it can change +the p h of blood. + +So even though you have this +buffering system, it can + +overwhelm the buffering system +and cause a change in the p h, + +which can lead to neurological +disorders and sometimes death. + +So they can look for this in +newborns, they can do a test, + +and I was -- one of the tests is +-- it's not in every state, + +but it is in Massachusetts, so +my daughter, Samantha, had + +this test. But they can simply +look at the urine of a newborn + +and look at the p h +and whether any of + +this is being excreted. + +And some infants that have this +condition can excrete + +like a gram of this +acid a day. + +So it's really large quantities +of acid that are + +excreted and it goes beyond +the buffering capacity. + +So, I'm going to tell you a +little story and it sort of + +emphasizes some of the + +importance of genetic research. + +So before the human genome +project, scientists were + +trying to find the gene to +figure out what was wrong with + +these patients that had +this condition. + +And here are all +the amino acids + +translated from the gene. + +This is not a small protein, +that's a lot of amino acids. + +And they found that the problem +was right here, or one + +of the main problems +is right here. + +There's a glycine residue, which +glycine is the smallest + +amino acid and that had been +changed to something else and + +that led to the disease. + +Now I want you to imagine if +you were parents of a small + +child and you found out your +child had this condition and + +then you had heard that there +were advances, they now know + +what caused it, and so, they +went to the doctor and the + +doctor said, yes, your child, +the DNA is wrong, and so let's + +substitute a different amino +acid for glycine here. + +OK. + +What does that do for you? + +Like why is that a problem? + +Well, they didn't know why it +was a problem, they just knew + +that it had the wrong +amino acid in there. + +And so, the next step was to +try to understand what was + +actually going on. + +So what happened in this case +was that the vitamin B12 + +cofactor had changed its +conformation when it bound to + +the protein. + +And instead of having this sort +of loop structure here, + +it had more of a tail. + +So this base here had moved +down, and so there was a + +different shape to the vitamin +than had been expected. + +So when the first structure +was solved of one of these + +enzymes, it found that here's +kind of what the vitamin B12 + +looked like, it had this +extended region which no one + +was expecting, and so that had +to fit into the protein. + +So this is the domain of the +protein that binds the + +vitamin, and it had a large +hole, and you put these + +together and that's +great, it fits and + +you have happy enzyme. + +Well, how do you create a hole +-- nature supposedly abhors a + +vacuum, so how do you +have this hole? + +Well, what nature did was it put +the smallest amino acids + +there are, glycines, right along +here to make room for + +this to fit together. + +So, what was happening in this +genetic case is that the + +switch of a glycine to an +argenine did this to the hole. + +So, what people were trying to +do is treat these patients + +with extra B12, you give them +injections of it, you have a + +lot more B12, and you want to +the B12 to bind and get the + +activity back going again. + +But really, no matter how much +vitamin B12 you added to it, + +it wasn't really going to do +much good, it just wasn't + +going to fit. + +So instead, there was a +suggestion that instead of + +giving the whole vitamin, +perhaps you could just give a + +truncated version of the +vitamin, which was + +commercially available, and +that that might bind and + +restore activity +of the protein. + +So this is what was suggested +once you knew what the problem + +actually was. + +So this is just an example of +a genetic disease, and it's + +not that common, but as I said, +it is tested for here in + +Massachusetts. + +And how knowing something about +what the problem is can + +lead to a potential solution. + +But for most of you, your blood +is doing just fine, you + +don't have a genetic condition +which is pumping too much acid + +into your bloodstream, so that +nature's buffering capacity is + +working quite well. + +So buffers are important. + +It's great to have my +important statements + +emphasized up there. + +We've been rehearsing at home. + +OK. + +So let's do a sample +buffer problem. + +All right, suppose we have an +acid, 0.1 moles of an acid, + +and 0.5 moles of its conjugate +base added in + +the form of a salt. + +And so they're put into water +and diluted to 1.0 liter. + +And you're given information +about the k a of the acid, 1 . + +77 times 10 to the minus +4, and you're asked to + +calculate the p h. + +So what do you do? + +All right, first, it's always +good to write the equation + +that you're talking about. + +And so you have acid in water +forming hydronium ions and the + +conjugate base. + +So here, the acid is giving up a +proton to the water, forming + +h 3 o plus and it's +conjugate base. + +Now we want to think about what +happens at equilibrium. + +So we know how many moles we +have and we know what the + +total volume is. + +And in this table we should be +using molarity, but the math + +here is pretty easy because we +have 1 mole and 1 liter or 1, + +and 0.5 moles in 1 liter +or 0.5 for molarity. + +And now at equilibrium what's +going to happen, well, when + +this equilibrates some of this +will go away and more of these + +are going to be formed. + +So we have minus x over here, +plus x and plus x over there, + +and we add it all together +you get 1 minus x plus x + +and 0.5 plus x. + +So the important thing to +remember is in buffering + +problems, you have the acid +and the conjugate. + +So we're used to seeing these +tables where we only have + +something over here and it's +all zero on the other side. + +But in a buffering problem, you +have things on both sides + +from the very beginning. + +And that's a really important +point, and that alone, if you + +can remember that, will +get you a long way + +through this unit. + +So you remember that in a buffer +you got to have both an + +acid in its conjugate base or a +base in its conjugate acid. + +So here we're talking about an +acid in water, it's an acidic + +buffer, and so we can use our +k a value -- we want to know + +what the concentrations +are at equilibrium to + +calculate our p h. + +So we can use our k a and we can +set it up, so we have on + +the top products over reactants, +and we we're not + +including water in this +because it's dilute in + +solution and so it's not +changing very much. + +And now we can plug in our +values, so we have 0.5 plus x, + +x over 1 minus x. + +All right, now this is just +written again from the last + +slide, we can try an +approximation, which is it + +that x is small compared to +1 molar or 0.5 molar. + +And so we can get rid of the +plus x and the minus x down + +here and just have one x term, +which makes it simpler to + +solve, but we'll have to +go back and check that + +approximation in +a few minutes. + +So making that approximation, +we can calculate x as 3 . + +54 times 10 to the minus 4 +molar, and now we need to + +check that assumption. + +Well, you can probably guess +it's going to be OK, because + +something times 10 to the minus +4 compared to 0.5 and 1, + +that's probably going to +be OK that it's small. + +But our assumption here is that +it needs to be less than + +5%, and here it's 0.1%. + +So you could just take this +value of x, divide it by the + +smaller of the two, 0.5 , times +100, and calculate the + +percent ionization. + +If it's less than 5% you're OK, +if it's more you need to + +use the quadratic equation +to solve the problem. + +So x here is our concentration +of hydronium ion, which is + +great, because then we can +easily calculate the p h. + +So p h again is minus log +of the hydronium ion + +concentration, and so +the p h here is 3 . + +45. + +And again, significant figures, +we'll be talking + +about this as we go through. + +The volume had two, it was 1 . + +0 liters, and so we're going +to have two significant + +figures after the decimal point, +because the volume was + +limiting insignificant +figures. + +All right, now let's consider +what happens if some strong + +acid had been added +in the solution. + +So the volume is still going +to be 1 liter, because the + +acid was added in before we went +up to the 1 liter mark. + +So strong acids, they +go to completion. + +So, if we added 0.1 moles of +that strong acid, it will + +react with equal number of moles +of the conjugate base to + +form the conjugate acid. + +So we can just do subtractions +here. + +We don't have to worry about +setting up any kind of + +equilibrium, we assume +it goes completely. + +So for the conjugate base we had +0.5 moles before, and it's + +going to be reacting then with a +strong acid, so 0.1 of those + +will react, leaving us with 0.4 +moles of the conjugate, + +and that's in 1 liter. + +So now we have 0.4 molar. + +For the acid, we had 1 mole to +begin with, but now we formed + +more as they reaction +has taken place, and + +so we have 0.1 more. + +Now we have 1 . + +1 moles again in 1 liter. + +So now we can do the +same thing again. + +So after this has happened, +after we have added the strong + +acid, then a new equilibrium +is going to be reached. + +And so we can plug in +this table as well. + +So we have 1 . + +1 now over here, and 0.4 +on the other side. + +As equilibrium is approached, +you lose some of the acid as + +it reacts with water and ionizes +and you form more of + +the h 3 o plus and more +of the conjugate. + +So we have 1 . + +1 minus x, x, and 0.4 plus x. + +So again, the trick here is just +to remember that there is + +a reaction with a strong acid +that has been added, and you + +need to figure out the new +molarities, and then go back + +to your equilibrium table with +those new molarities. + +So here we can set up with a +k a again, and do the same + +problem that we did before. + +And so, we can make the +assumption again that x is + +small, try it out and +see if it works. + +X turns out to be 4 . + +87 times 10 to the minus 4 +molars -- so again, it's a + +small number. + +And so, it turns out to be 1 +. -- less than 1% of 0.4 . + +If it's less than 5% of the +smaller number, you don't have + +to worry about the bigger +number, and so your assumption + +is OK, you don't need to use +the quadratic equation. + +And so, then we can calculate +at the end that the + +p h is now 3 . + +31, again, two significant +figures after the decimal + +place because of the volume. + +So addition of 0.1 moles of +a strong acid changed + +our p h from 3 . + +45 to 3 . + +31. + +So we buffered pretty well. + +There was a change in p h, we +added acid and the p h did go + +down, but not by an +enormous amount. + +And so, that's because this +turned out to be a pretty + +decent buffer here, +so we didn't have + +a really huge effect. + +So, those are -- that's an +example of a buffer problem. + +So, let's think for a minute +about designing a buffer. + +Suppose you wanted to create a +buffer at a particular p h, + +what do you need +to think about? + +Well, you need to think about +the ratio of your acid to the + +conjugate, and you need to think +about the p k a of the + +acid, and the p h +that's desired. + +So here is a generic equation +for an acid in water, so we + +have our acid, h a, in water +forming hydronium ions and our + +conjugate base. + +And now we're going to do a +little derivation to come up + +with an equation that would be +useful to you in thinking + +about buffers and designing +buffers. + +So, we can write a generic +term for k a. + +K a equals products over +reactants, and so we have our + +hydronium ions are conjugate +base over our acid. + +And now we can take this +term and rearrange it. + +So we can pull a hydronium ion + +concentration over to one side. + +And now we're going to take the +logs of both sides, so we + +get the log of hydronium ion +concentration, the log of k a, + +and the log of h a concentration +over a minus + +concentration, and now we're +going to multiply everything + +by negative sign, so we have +minus logs of things. + +And I'm just going to move this +now up to the top of the + +screen, and we have +this equation. + +So what is minus log of +hydronium ion concentration? + +P h. + +What's minus log of k a? + +P k a. + +So, we have p h equals p +k a minus the log of a + +concentration of your acid over +the concentration of your + +conjugate base. + +And these are equilibrium +concentrations for that, + +because remember, we derived +it from our equilibrium + +expression for k a. + +But a lot of times when you're +working buffer problems, you + +know the concentrations that you +added of these things, not + +necessarily the concentrations +of equilibrium. + +And if we rewrite this +expression in terms of the + +initial concentrations or +original or o concentrations, + +then we have p h is +approximately equal to p k a + +minus log of the initial +concentrations of your acid + +over your conjugate base. + +And this is known as a + +Henderson Hasselbalch equation. + +And people love the Henderson +Hasselbalch equation, and it + +can be incredibly useful to you +in solving these problems. + +But I'm going to emphasize when +it's OK to use it and + +when it's not OK to use it, +because people try to apply it + +to everything, and it's for +buffer problems, and people + +apply it to all sorts of things +that are not buffer + +problems. So I want to make sure +that it's clear when you + +can use it and when +you can't use it. + +And it's fine to use it and you +should use it when it's + +acceptable, but not +at other times. + +It's one of the few equations +in acid base, so people get + +very excited by it. + +All right, so remember that it's +really equal when they're + +at equilibrium concentrations, +and this is just an + +approximation that we're saying +that those are initial + +concentrations. + +So when is it OK to say well, +the equilibrium concentration + +is more or less the same as +the initial concentration. + +And that's true when x, which is +in this particular example + +your hydronium ion +concentration, is small + +compared to your initial +concentration of the acid and + +the conjugate base that you +added to the buffer. + +So, and when x is small, then +pretty much, the equilibrium + +concentration equals the +initial concentration. + +So there's not really very much +change if x is a really + +small number. + +So, a lot of the time +this is true. + +Remember, we're making buffers +from weak acids and weak + +conjugate bases, and the +definition of a weak acid is + +that it only loses a tiny +fraction of its protons. + +It only ionizes slightly +in water. + +And a weak base typically only +accepts a fraction of the + +protons it can accept. + +It's a weak base, so it's +not doing a whole lot + +of chemistry there. + +So this approximation is +good a lot of the time. + +So just you know when you can +and can not use it, we're + +going to give a rule and say +it's the same rule as before. + +When we say when x is small +or your hydronium ion + +concentration is small compared +to the acid or the + +conjugate base, when it's less +than 5%, that's what we're + +going to call small, so +the same rule we've + +been using all along. + +When x is small, this +approximation + +works pretty well. + +And you can plug in your +concentrations right there -- + +your initial concentrations +not your equilibrium + +concentrations. + +All right, so let's use +Henderson Hasselbalch and + +design a buffer system if +we want a p h of 4 . + +6. + +And a good rule to remember is +that a buffering solution is + +most effective when it's +plus or minus 1 away + +from the p k a. + +So that's a good thing +too I keep in mind + +for research as well. + +If you're really far away from +the p k a, it's not going to + +be a good buffering system, +and this is a mistake the + +people make in the lab +sometimes, so you may run into + +that in some of your +laboratory courses. + +So we want a buffer +about p h 4 . + +6. + +So we can look at our ionization +constants of acid, + +and of course, we're always +doing everything at room + +temperature in this unit, and so +we can look at what p k a's + +are of some weak acids, and +acetate, acetate is an easy + +buffer to get your hands on, +acetate is quite available, + +and it has a good p k a 4 . + +75. + +So that's great, we can use that +in designing our buffer. + +So, acetic acid has the right +p k a, and we're all set, we + +can prepare a buffer. + +But we'll need to add the acid +and the conjugate, and we need + +to know how much acid and how +much of the conjugate to add. + +So we can use Henderson +Hasselbalch equation for this. + +We're creating a buffer, and so +this is an equation we can + +use for buffers. + +We know what p h we want, we +know the p k a of the thing + +we're going to use, and we want +to figure out how much of + +the acid to use and how much +of the conjugate to use. + +We need to know the ratio of one +to the other to set up our + +buffer ideally. + +So we can plug our numbers +in and calculate that. + +So, we can rearrange this if you +want so that the unknown + +is on one side and we have +to p k a and the p h + +on the other side. + +And so, we have here our p k a +minus our p h and we get 0 . + +15. + +Now we need to inverse log and +come up with the ratio, and + +the ratio that we want is 1 . + +4. + +So we want to have a ratio +from our acid to the + +conjugate of 1 . + +4. + +Well how much exactly are we +going to add them, we know the + +ratio now, how much are +we going to add? + +Well, you could use 1 . + +4 molar and 1 molar, for +example, that would have the + +correct ratio. + +But how do you know if that's +going to be good? + +Well, the ratio is more +important than the exact + +amounts, however, the amounts +get to this issue of sort of + +the capacity of the buffer -- +how resistant it is to changes + +in the p h. + +So if you use too low +concentrations of both, it + +won't be all that resistant. + +So if you need to have a better +buffering capacity, the + +higher concentrations +that you should use. + +And you can use Henderson +Hasselbalch then to calculate + +what sort of the minimum amount +you use, the minimum + +amount to have that +5% rule work. + +So in the example I told you +about this condition, the + +buffer in the blood was pretty +good, but the acid with so + +much that it overwhelmed +buffering capacity. + +So if there had been larger +concentrations of the buffer, + +that would have certainly +helped in that case. + +So the higher the concentrations +you use, the + +more resistant to change. + +And that's the idea of +buffering capacity. + +So, and if you use too low +concentrations, then your + +Henderson Hasselbalch equation +won't even be valid. + +So we can go back and calculate +what is sort of the + +minimum concentrations we need +to use for Henderson + +Hasselbalch to be valid +to meet that 5% rule. + +So for a p h of 4 . + +6, a hydronium ion concentration +is a 2 . + +5 times 10 to the minus 5. + +And so then if we work our +equation backwards, we want to + +be less than 5%, so we have this +over the concentration of + +either one of those times +100% gives you 5%. + +So the concentrations need to be +greater than 5 times 10 to + +the minus 4 moles or you won't +meet this 5% rule. + +So at least to be greater than +that and they need to be in + +the right ratio. + +Other than that you're somewhat +free to decide what + +you're going to do with that, +and there may be other + +considerations involved if +you're working with a certain + +concentration of protein, you +might not want your buffer + +concentration to be too high, +it might start interfering + +with enzyme assay, +for example. + +And often buffers are +somewhere around 100 + +millimolar, that's +a pretty common + +concentration for buffers. + +All right, so this slide we're +doing really well. + +So we talked about weak acids in +water, weak bases in water, + +and I'm trying to convince you +that these are the same as the + +salt and water problems. So +we're going to talk much more + +about salt and water +in a few minutes. + +And I told you about buffers, +so we only have 2 + +more things to go. + +We need to talk about strong +acids in water, and strong + +bases in water, and then you'll +have all of the 5 types + +of problems to do +the problem-set. + +And as I mentioned last time, +it looks deceivingly short, + +the number of questions on +them, but the titration + +problems are long. + +So don't leave those to the last +minute or there will not + +be a whole lot of +sleep involved. + +So just a word of warning from +the past. Everyone looks and + +go, "Oh, this is an easy +problem-set, there aren't many + +problems." So, titration +problems do + +take a lot of time. + +So let's talk about titration, +so that as soon as class is + +over today, you can go work +on those questions on the + +problem-set. + +All right. + +So acid base titrations. + +How many of you in high school +titrated an acid with a base? + +Large fraction of you, OK. + +So usually what titration +problems are meant to do, that + +you have something known about +an acid or a base, base say of + +known concentration, and and +acid of unknown concentration + +or maybe unknown molecular +weight, and you're titrating + +them out, titrating them +together to find missing + +information. + +So you can determine +concentration, sometimes you + +can determine a molecular +weight. + +All right, so here's what a plot +looks like and some of + +the key terms involved in +acid base titrations. + +So you have a p h on one side, +and then volume of either base + +or acid added on +the other side. + +So p h versus a volume. + +And the actual experiment here, +you have a base that + +you're dripping, one drip at +a time supposedly into your + +strong acid. + +And then you're looking to +figure out when you're going + +to reach the either equivalence +point or the end + +point, these are basically the +same terms. It's also called + +the stoichiometric point, and +often equivalence point is + +used as a more theoretical +amount of volume is added, + +where as end point is the +experimentally measured. + +So we're going to be talking a +lot about equivalence points, + +because we have no lab +associated with this course, + +so everything will be +theorectical in terms of + +these, but they should +be the same. + +So, many times you will measure +p h with the p h meter + +-- this just shows +a p h meter. + +And for those of you who have +done these experiments, this + +should look familiar. + +And for those of you who +haven't, often what you're + +doing when you're dripping +something in, you're waiting + +for an indicator dye to change +color as an indication that + +you have reached the end +point, and often you're + +adding, and it's clear, clear, +clear for what seems to be + +forever, and just as you get +incredibly impatient, you + +start adding it faster and +you go all the way + +to this dark color. + +And what you want is this very, +very, very light changed + +color that indicates +the end point. + +So you usually go too slow and +then go too fast and then have + +to do the experiment +over again. + +Those of you who know how to +calculate theoretical values + +could sit down and do a +calculation first and then go + +really fast right until you get +around this point and add + +it really slowly, and be +done with lab sooner. + +So, we'll talk about how you +do the theoretical value, + +which could save you a lot of +time if you ever run across + +these labs in any +future class. + +So, here are the two curves that +you would see for either + +a strong acid with a strong +base, or strong base with a + +strong acid. + +So if you're titrating a strong +acid with a strong + +base, you're going to start +down being very acidic, + +because all you have is +your strong acid. + +And then as you add in base, +the p h will go up. + +You'll reach this point -- s +is for the stoichiometric + +point, we also call this, again, +the equivalence point, + +and then it'll continue to go up +and then start to level off + +a bit more up here. + +If you're going the other +direction, you're starting + +with strong base, your p h is +going to be high, and the p h + +will decrease as you +add the acid. + +And then you get to the +stoichiometric or equivalence + +point in the middle of +this curve here. + +And then as you go down farther, +more acidic, it + +starts to level off. + +So those are what the titration +curves look like. + +So let's do an example. + +We're going to have a strong +base being titrated with a + +strong acid first. And our +strong base is n a o h, and + +our strong acid is h c l. + +So let's calculate the p h +at the equivalence point. + +Well, let's just calculate +the p h at 5 mils -- + +I don't know whether it's +equivalence point, actually. + +5 mils of this have been added +to the amount of base. + +So we have 25 mils of our strong +base at 0.15 molar + +concentration, and we're adding +5 mils of our 0.34 + +molar acid. + +So what we want to do is figure +out how many moles of + +base we had to start with. + +So how many moles of o h minus +-- again, n a o h is a strong + +base, so however much n a o h +you add, is the amount of o h + +minus you get, and so we just +put in the number of liters + +times the concentration +to get moles. + +We don't need any equilibrium +table here. + +So then we want to figure out +the amount of acid added when + +you're adding 5 mils of it. + +So again, h c l is a strong +acid, so the amount of h c l + +added equals the amount of h 3 o +plus, that's formed, goes to + +completion, and so we added 5 +mils, the concentration was + +0.34 molar, so we have 1 . + +7 times 10 to the +minus 3 moles. + +So now, the strong acid is going +to react with the strong + +base, and we want to figure out +how much of the base is + +left, how much hydroxide ion is +left after it reacts with + +the hydronium ions. + +So it'll react 1:1, +so we had 6 . + +25 times 10 to the minus 3 +moles, and we added 1 . + +7 times 10 to the minus 3 moles +of the acid, so we're + +going to have 4 . + +55 times 10 the minus +3 moles left. + +And now we can calculate the +molarity here, so we have the + +number of moles and the new +volume, so we had 25 mils to + +the base to begin with. + +We've added 5 mils to the acid, +so our new volume is 30, + +and so we have our new +concentration. + +And now we can calculate p h. + +First we'll calculate p o h, and +then use 14 minus to get + +the new p h. + +So if you were making your own +little titration curve, we + +could have volume of acid on one +side and p h on the other + +side, and you have +a point of 13 . + +18. + +That's how much we have after +you have 5 mils added. + +So we didn't, in this curve, we +have not measured the zero + +point, but we know what one +point after 5 mils of the acid + +has been added. + +So now let's go right to the +equivalence point -- so the + +way I draw it should indicate +that was not + +an equivalence point. + +So we want to figure out how +much we need to add of the + +acid to reach the equivalence +point. + +So the equivalence point or the +stoichiometric point means + +that you add the same amount +of moles of your titrate as + +you had, and so they're going +to be equal to each other. + +So if you're adding acid to a +strong base, you've added + +enough acid that you now have +equal number of moles to the + +number of moles of base that +you had to begin with. + +So we know we have 6 . + +25 times 10 to the +minus 3 moles of + +the base were present. + +So at the equivalence point, +you need to have that exact + +same number of moles of acid. + +So we know the concentration +of the acid we have and the + +number of moles we need, and +so we can calculate the + +volume, which is 18 . + +4 millimeters, or +0.0184 liters. + +So what would the p h then be +of the equivalence point? + +We're titrating a strong acid +with a strong base, what + +should the p h be? + +The p h should be 7. + +So somewhere around here we're +going to be at 18, so you can + +just try to draw a curve, and +here we have a p h of 7 when + +we've gone to about 18 . + +4 milliliters added. + +So when you titrate a strong +acid with a strong base, you + +form a salt that's neutral. + +Because the conjugates of a +strong acid and a strong base + +are not basic or acidic. + +They're ineffective as acids or +bases, so you're going to + +get a neutral salt. + +So if you're doing a problem +with a strong acid and strong + +base, it's not a lot of +calculations that need to be + +done at this point, you just +need to recognize that your + +salt should be neutral. + +So now, we can talk about what +happens if you add an extra + +milliliter of your acid, after +you've reached that + +equivalence point, which is +something that people probably + +have done in doing these +titrations not meaning to, + +gone well beyond the +equivalence point. + +So first we can find out the +number of moles of the strong + +acid that we've added extra, +so we added one mil of the + +strong acid, and so again, +it goes to completion. + +The concentration, the acid, is +0.34 molar times our 1 mil, + +so we've added 3 . + +4 times 10 to the minus 4 extra +moles of our acid, and + +so let's calculate then what the +molarity is that we have + +added that was extra. + +And even if you don't +have a calculator, + +we've helped you out. + +Let's just take 10 +more seconds. + +I think this is a +first, isn't it? + +Did I mention it's a +good idea to start + +the problem-set early. + +So the trick here was +about the volume. + +So we had 25 mils to begin +with, then we added 18 . + +4 to get to the equivalence +point, and then we're 1 mil + +beyond the equivalence point. + +And the tricks to these parts +of the problems are to + +remember all the things +that have been added + +to get to the volume. + +So the problem itself is not +very tricky of having just an + +acid in water, but the one trick +is in calculating the + +molarity, remembering all of the +things that were added to + +get to this point. + +And so by the end of the +problem-set this should be + +pretty familiar to you, but it's +also something that you + +want to make sure that you check +on an exam that you're + +not making any volume +mistakes. + +So again, here are the things +that you want to remember to + +add in in calculating this. + +And then, if you calculate +the p h of that, you + +get a p h of 2 . + +1106, so that's down +somewhere in here. + +We've added 1 more mill, and +we're at a p h of 2 . + +1106, and this can be +a check as well. + +If you forgot to add some of +your volume, you might get a p + +h that doesn't make +a lot of sense. + +So that can be a double check. + +Always ask yourself when you +have a strong base and you're + +adding acid, before you've +added very much, your p h + +should be basic. + +At the equivalence point of +a strong acid, strong base + +titration, it'll be 7. + +And if you continue to add acid, +then you should have a + +pretty low p h, you'll notice +the curve drops off pretty + +fast. So it should be a dramatic +change in p h by + +adding extra of your acid. + +So always check your work. + +OK, so let's stop there, and +we're going to weak acid, weak + +base titrations next time. \ No newline at end of file diff --git a/aiSpEUZzP0A.txt b/aiSpEUZzP0A.txt new file mode 100644 index 0000000000000000000000000000000000000000..169ef454de72fe7b59ad0dd52358e41100cc2e2a --- /dev/null +++ b/aiSpEUZzP0A.txt @@ -0,0 +1,699 @@ +align:start position:0% + +many of you have heard of mukes uh + + align:start position:0% +many of you have heard of mukes uh + + + align:start position:0% +many of you have heard of mukes uh +they're very famous massively open + + align:start position:0% +they're very famous massively open + + + align:start position:0% +they're very famous massively open +online courses muks are very uh open and + + align:start position:0% +online courses muks are very uh open and + + + align:start position:0% +online courses muks are very uh open and +large classes often with thousands or + + align:start position:0% +large classes often with thousands or + + + align:start position:0% +large classes often with thousands or +tens of thousands of + + align:start position:0% +tens of thousands of + + + align:start position:0% +tens of thousands of +participants and muks are essentially um + + align:start position:0% +participants and muks are essentially um + + + align:start position:0% +participants and muks are essentially um +a big movement to really Dem democratize + + align:start position:0% +a big movement to really Dem democratize + + + align:start position:0% +a big movement to really Dem democratize +education Sparks a little different so + + align:start position:0% +education Sparks a little different so + + + align:start position:0% +education Sparks a little different so +1684 842 was run as a Spock which stands + + align:start position:0% +1684 842 was run as a Spock which stands + + + align:start position:0% +1684 842 was run as a Spock which stands +for small private online course so like + + align:start position:0% +for small private online course so like + + + align:start position:0% +for small private online course so like +a moo a Spock is also offered online you + + align:start position:0% +a moo a Spock is also offered online you + + + align:start position:0% +a moo a Spock is also offered online you +can take it in person in a classroom at + + align:start position:0% +can take it in person in a classroom at + + + align:start position:0% +can take it in person in a classroom at +one of the hosting + + align:start position:0% +one of the hosting + + + align:start position:0% +one of the hosting +universities uh or you can take it + + align:start position:0% +universities uh or you can take it + + + align:start position:0% +universities uh or you can take it +entirely online it's it's really up to + + align:start position:0% +entirely online it's it's really up to + + + align:start position:0% +entirely online it's it's really up to +you it's small because we have a few + + align:start position:0% +you it's small because we have a few + + + align:start position:0% +you it's small because we have a few +dozen students instead of thousands and + + align:start position:0% +dozen students instead of thousands and + + + align:start position:0% +dozen students instead of thousands and +um it's private because in order to take + + align:start position:0% +um it's private because in order to take + + + align:start position:0% +um it's private because in order to take +the class it's by invitation + + align:start position:0% +the class it's by invitation + + + align:start position:0% +the class it's by invitation +in this particular instance we had two + + align:start position:0% +in this particular instance we had two + + + align:start position:0% +in this particular instance we had two +universities that co-sponsored this + + align:start position:0% +universities that co-sponsored this + + + align:start position:0% +universities that co-sponsored this +class one is MIT and the other one is + + align:start position:0% +class one is MIT and the other one is + + + align:start position:0% +class one is MIT and the other one is +called epfl E po technique Federal de + + align:start position:0% +called epfl E po technique Federal de + + + align:start position:0% +called epfl E po technique Federal de +Loan in Switzerland which is also quite + + align:start position:0% +Loan in Switzerland which is also quite + + + align:start position:0% +Loan in Switzerland which is also quite +active in the in the world of online + + align:start position:0% +active in the in the world of online + + + align:start position:0% +active in the in the world of online +education the way fundamentally that a + + align:start position:0% +education the way fundamentally that a + + + align:start position:0% +education the way fundamentally that a +Spock works is that you have the course + + align:start position:0% +Spock works is that you have the course + + + align:start position:0% +Spock works is that you have the course +management system at each of the hosting + + align:start position:0% +management system at each of the hosting + + + align:start position:0% +management system at each of the hosting +universities and institutions and you + + align:start position:0% +universities and institutions and you + + + align:start position:0% +universities and institutions and you +essentially post the same materials the + + align:start position:0% +essentially post the same materials the + + + align:start position:0% +essentially post the same materials the +lectures the readings the exercise is + + align:start position:0% +lectures the readings the exercise is + + + align:start position:0% +lectures the readings the exercise is +you post them in parallel at each of the + + align:start position:0% +you post them in parallel at each of the + + + align:start position:0% +you post them in parallel at each of the +hosting universities the lectures + + align:start position:0% +hosting universities the lectures + + + align:start position:0% +hosting universities the lectures +themselves however are Run online using + + align:start position:0% +themselves however are Run online using + + + align:start position:0% +themselves however are Run online using +you know an open collaboration platform + + align:start position:0% +you know an open collaboration platform + + + align:start position:0% +you know an open collaboration platform +like WebEx for example you can do it + + align:start position:0% +like WebEx for example you can do it + + + align:start position:0% +like WebEx for example you can do it +with Google Hangouts there's a lot of + + align:start position:0% +with Google Hangouts there's a lot of + + + align:start position:0% +with Google Hangouts there's a lot of +different platforms and this is + + align:start position:0% +different platforms and this is + + + align:start position:0% +different platforms and this is +important because um it is important to + + align:start position:0% +important because um it is important to + + + align:start position:0% +important because um it is important to +have live connections between the + + align:start position:0% +have live connections between the + + + align:start position:0% +have live connections between the +faculty and the students but also the + + align:start position:0% +faculty and the students but also the + + + align:start position:0% +faculty and the students but also the +students amongst themselves can discuss + + align:start position:0% +students amongst themselves can discuss + + + align:start position:0% +students amongst themselves can discuss +the trickiest part of running a Spock of + + align:start position:0% +the trickiest part of running a Spock of + + + align:start position:0% +the trickiest part of running a Spock of +course is the time zones and the time + + align:start position:0% +course is the time zones and the time + + + align:start position:0% +course is the time zones and the time +differences in this case uh the two + + align:start position:0% +differences in this case uh the two + + + align:start position:0% +differences in this case uh the two +universities were six time zones apart + + align:start position:0% +universities were six time zones apart + + + align:start position:0% +universities were six time zones apart +and so it was offered in the morning + + align:start position:0% +and so it was offered in the morning + + + align:start position:0% +and so it was offered in the morning +here at MIT and in the afternoon in + + align:start position:0% +here at MIT and in the afternoon in + + + align:start position:0% +here at MIT and in the afternoon in +Europe if you're running this as a + + align:start position:0% +Europe if you're running this as a + + + align:start position:0% +Europe if you're running this as a +global class it will be more challenging + + align:start position:0% +global class it will be more challenging + + + align:start position:0% +global class it will be more challenging +to find a time slot that works for + + align:start position:0% +to find a time slot that works for + + + align:start position:0% +to find a time slot that works for +everybody the feedback from the students + + align:start position:0% +everybody the feedback from the students + + + align:start position:0% +everybody the feedback from the students +uh has been very positive because you + + align:start position:0% +uh has been very positive because you + + + align:start position:0% +uh has been very positive because you +can think of a Spock in this particular + + align:start position:0% +can think of a Spock in this particular + + + align:start position:0% +can think of a Spock in this particular +class as a blended form of Education + + align:start position:0% +class as a blended form of Education + + + align:start position:0% +class as a blended form of Education +part of the class is live the lectures + + align:start position:0% +part of the class is live the lectures + + + align:start position:0% +part of the class is live the lectures +are given live and every lecture is + + align:start position:0% +are given live and every lecture is + + + align:start position:0% +are given live and every lecture is +recorded so even if you miss a lecture + + align:start position:0% +recorded so even if you miss a lecture + + + align:start position:0% +recorded so even if you miss a lecture +as a student you can watch it later and + + align:start position:0% +as a student you can watch it later and + + + align:start position:0% +as a student you can watch it later and +so there's a record of it uh the + + align:start position:0% +so there's a record of it uh the + + + align:start position:0% +so there's a record of it uh the +assignments are asynchronous and there + + align:start position:0% +assignments are asynchronous and there + + + align:start position:0% +assignments are asynchronous and there +are some assignments that are individual + + align:start position:0% +are some assignments that are individual + + + align:start position:0% +are some assignments that are individual +and there are team assignments as well + + align:start position:0% +and there are team assignments as well + + + align:start position:0% +and there are team assignments as well +and so it's a blended form of Education + + align:start position:0% +and so it's a blended form of Education + + + align:start position:0% +and so it's a blended form of Education +which is an important Trend in education + + align:start position:0% +which is an important Trend in education + + + align:start position:0% +which is an important Trend in education +where we take the best of the online + + align:start position:0% +where we take the best of the online + + + align:start position:0% +where we take the best of the online +experience and we try to combine it with + + align:start position:0% +experience and we try to combine it with + + + align:start position:0% +experience and we try to combine it with +best the best of the in-person + + align:start position:0% +best the best of the in-person + + + align:start position:0% +best the best of the in-person +experience teaching a Spock is uh fun + + align:start position:0% +experience teaching a Spock is uh fun + + + align:start position:0% +experience teaching a Spock is uh fun +and challenging at the same time it's + + align:start position:0% +and challenging at the same time it's + + + align:start position:0% +and challenging at the same time it's +fun because you get to converse and um + + align:start position:0% +fun because you get to converse and um + + + align:start position:0% +fun because you get to converse and um +interact with students not just in a + + align:start position:0% +interact with students not just in a + + + align:start position:0% +interact with students not just in a +physical classroom at one University but + + align:start position:0% +physical classroom at one University but + + + align:start position:0% +physical classroom at one University but +across multiple + + align:start position:0% +across multiple + + + align:start position:0% +across multiple +institutions and um and and that + + align:start position:0% +institutions and um and and that + + + align:start position:0% +institutions and um and and that +enhances the class because students will + + align:start position:0% +enhances the class because students will + + + align:start position:0% +enhances the class because students will +speak up with experiences from different + + align:start position:0% +speak up with experiences from different + + + align:start position:0% +speak up with experiences from different +cultural backgrounds uh but it's also + + align:start position:0% +cultural backgrounds uh but it's also + + + align:start position:0% +cultural backgrounds uh but it's also +challenging because you have to keep + + align:start position:0% +challenging because you have to keep + + + align:start position:0% +challenging because you have to keep +track of what's happening at uh at + + align:start position:0% +track of what's happening at uh at + + + align:start position:0% +track of what's happening at uh at +multiple places and you have a mix of + + align:start position:0% +multiple places and you have a mix of + + + align:start position:0% +multiple places and you have a mix of +students from from from different + + align:start position:0% +students from from from different + + + align:start position:0% +students from from from different +backgrounds and uh different you know + + align:start position:0% +backgrounds and uh different you know + + + align:start position:0% +backgrounds and uh different you know +institutional uh constraints as well and + + align:start position:0% +institutional uh constraints as well and + + + align:start position:0% +institutional uh constraints as well and +so it's both challenging and fun but + + align:start position:0% +so it's both challenging and fun but + + + align:start position:0% +so it's both challenging and fun but +it's a very focused experience and the + + align:start position:0% +it's a very focused experience and the + + + align:start position:0% +it's a very focused experience and the +the feedback from the students has been + + align:start position:0% +the feedback from the students has been + + + align:start position:0% +the feedback from the students has been +great \ No newline at end of file diff --git a/auK3PSZoidc.txt b/auK3PSZoidc.txt new file mode 100644 index 0000000000000000000000000000000000000000..7504fb3eba469ce9ab42d4cada1e81d4532098fe --- /dev/null +++ b/auK3PSZoidc.txt @@ -0,0 +1,9723 @@ +align:start position:0% + +welcome back hope you had a good long + + align:start position:0% +welcome back hope you had a good long + + + align:start position:0% +welcome back hope you had a good long +weekend + + align:start position:0% +weekend + + + align:start position:0% +weekend +so today's puzzle is I guess a classic + + align:start position:0% +so today's puzzle is I guess a classic + + + align:start position:0% +so today's puzzle is I guess a classic +puzzle it's it's Sudoku I've never + + align:start position:0% +puzzle it's it's Sudoku I've never + + + align:start position:0% +puzzle it's it's Sudoku I've never +actually successfully managed to + + align:start position:0% +actually successfully managed to + + + align:start position:0% +actually successfully managed to +complete a pseudo Koopas all by myself + + align:start position:0% +complete a pseudo Koopas all by myself + + + align:start position:0% +complete a pseudo Koopas all by myself +because I've they fall into two + + align:start position:0% +because I've they fall into two + + + align:start position:0% +because I've they fall into two +categories for me either it's easy + + align:start position:0% +categories for me either it's easy + + + align:start position:0% +categories for me either it's easy +they're easy and and I get bored and I + + align:start position:0% +they're easy and and I get bored and I + + + align:start position:0% +they're easy and and I get bored and I +stop or they're too hard and I get lazy + + align:start position:0% +stop or they're too hard and I get lazy + + + align:start position:0% +stop or they're too hard and I get lazy +and I stop but what I have done is write + + align:start position:0% +and I stop but what I have done is write + + + align:start position:0% +and I stop but what I have done is write +a computer program that essentially + + align:start position:0% +a computer program that essentially + + + align:start position:0% +a computer program that essentially +solves any pseudocode puzzle that is put + + align:start position:0% +solves any pseudocode puzzle that is put + + + align:start position:0% +solves any pseudocode puzzle that is put +in front of it in in seconds maybe if + + align:start position:0% +in front of it in in seconds maybe if + + + align:start position:0% +in front of it in in seconds maybe if +there exists puzzles for which it would + + align:start position:0% +there exists puzzles for which it would + + + align:start position:0% +there exists puzzles for which it would +take minutes but I haven't discovered + + align:start position:0% +take minutes but I haven't discovered + + + align:start position:0% +take minutes but I haven't discovered +such puzzles and what we're going to do + + align:start position:0% +such puzzles and what we're going to do + + + align:start position:0% +such puzzles and what we're going to do +today is talk about Sudoku compare and + + align:start position:0% +today is talk about Sudoku compare and + + + align:start position:0% +today is talk about Sudoku compare and +contrast the human way of solving Sudoku + + align:start position:0% +contrast the human way of solving Sudoku + + + align:start position:0% +contrast the human way of solving Sudoku +puzzles against brute force way and then + + align:start position:0% +puzzles against brute force way and then + + + align:start position:0% +puzzles against brute force way and then +try and integrate the two together you + + align:start position:0% +try and integrate the two together you + + + align:start position:0% +try and integrate the two together you +know perhaps this is the closest we're + + align:start position:0% +know perhaps this is the closest we're + + + align:start position:0% +know perhaps this is the closest we're +going to get to AI in this class where + + align:start position:0% +going to get to AI in this class where + + + align:start position:0% +going to get to AI in this class where +we're going to try and marry an + + align:start position:0% +we're going to try and marry an + + + align:start position:0% +we're going to try and marry an +exhaustive search method with some + + align:start position:0% +exhaustive search method with some + + + align:start position:0% +exhaustive search method with some +smarts and back I think when we were + + align:start position:0% +smarts and back I think when we were + + + align:start position:0% +smarts and back I think when we were +doing the N Queens puzzle one of you + + align:start position:0% +doing the N Queens puzzle one of you + + + align:start position:0% +doing the N Queens puzzle one of you +asked a question about what the number + + align:start position:0% +asked a question about what the number + + + align:start position:0% +asked a question about what the number +of possibilities were you know for an + + align:start position:0% +of possibilities were you know for an + + + align:start position:0% +of possibilities were you know for an +eight Queens puzzle was at a trace to + + align:start position:0% +eight Queens puzzle was at a trace to + + + align:start position:0% +eight Queens puzzle was at a trace to +eight and I said well no you can prune + + align:start position:0% +eight and I said well no you can prune + + + align:start position:0% +eight and I said well no you can prune +the search by figuring out that + + align:start position:0% +the search by figuring out that + + + align:start position:0% +the search by figuring out that +particular partial configurations that + + align:start position:0% +particular partial configurations that + + + align:start position:0% +particular partial configurations that +correspond to perhaps two queens being + + align:start position:0% +correspond to perhaps two queens being + + + align:start position:0% +correspond to perhaps two queens being +placed on the 8x8 board already + + align:start position:0% +placed on the 8x8 board already + + + align:start position:0% +placed on the 8x8 board already +I does not correspond to a solution + + align:start position:0% +I does not correspond to a solution + + + align:start position:0% +I does not correspond to a solution +because the two queens conflict with + + align:start position:0% +because the two queens conflict with + + + align:start position:0% +because the two queens conflict with +each other and you can then shrink this + + align:start position:0% +each other and you can then shrink this + + + align:start position:0% +each other and you can then shrink this +eight raise to 8 substantially so that's + + align:start position:0% +eight raise to 8 substantially so that's + + + align:start position:0% +eight raise to 8 substantially so that's +exactly the methodology that we're going + + align:start position:0% +exactly the methodology that we're going + + + align:start position:0% +exactly the methodology that we're going +to follow here in trying to take our + + align:start position:0% +to follow here in trying to take our + + + align:start position:0% +to follow here in trying to take our +brute force solver which will work and + + align:start position:0% +brute force solver which will work and + + + align:start position:0% +brute force solver which will work and +you know given enough time on arbitrary + + align:start position:0% +you know given enough time on arbitrary + + + align:start position:0% +you know given enough time on arbitrary +Sudoku puzzles but + + align:start position:0% +Sudoku puzzles but + + + align:start position:0% +Sudoku puzzles but +may not want to wait that long and we're + + align:start position:0% +may not want to wait that long and we're + + + align:start position:0% +may not want to wait that long and we're +gonna take this strategy of pruning the + + align:start position:0% +gonna take this strategy of pruning the + + + align:start position:0% +gonna take this strategy of pruning the +search to try and improve the solve + + align:start position:0% +search to try and improve the solve + + + align:start position:0% +search to try and improve the solve +world and one last thing before I get + + align:start position:0% +world and one last thing before I get + + + align:start position:0% +world and one last thing before I get +started on the rules of Sudoku I'm we're + + align:start position:0% +started on the rules of Sudoku I'm we're + + + align:start position:0% +started on the rules of Sudoku I'm we're +going to have to have a way of measuring + + align:start position:0% +going to have to have a way of measuring + + + align:start position:0% +going to have to have a way of measuring +performance just like we can measure a + + align:start position:0% +performance just like we can measure a + + + align:start position:0% +performance just like we can measure a +trace to 8 or 4 raise to 4 or what have + + align:start position:0% +trace to 8 or 4 raise to 4 or what have + + + align:start position:0% +trace to 8 or 4 raise to 4 or what have +you we want to have a way of measuring + + align:start position:0% +you we want to have a way of measuring + + + align:start position:0% +you we want to have a way of measuring +outside of the particular machine that's + + align:start position:0% +outside of the particular machine that's + + + align:start position:0% +outside of the particular machine that's +being used we could obviously measure + + align:start position:0% +being used we could obviously measure + + + align:start position:0% +being used we could obviously measure +real time in terms of seconds but that's + + align:start position:0% +real time in terms of seconds but that's + + + align:start position:0% +real time in terms of seconds but that's +not as precise I you want to measure + + align:start position:0% +not as precise I you want to measure + + + align:start position:0% +not as precise I you want to measure +more precisely what the number of + + align:start position:0% +more precisely what the number of + + + align:start position:0% +more precisely what the number of +combinations are and so we could + + align:start position:0% +combinations are and so we could + + + align:start position:0% +combinations are and so we could +certainly instrument our code with + + align:start position:0% +certainly instrument our code with + + + align:start position:0% +certainly instrument our code with +appropriate counters that will allow us + + align:start position:0% +appropriate counters that will allow us + + + align:start position:0% +appropriate counters that will allow us +to measure this performance and so then + + align:start position:0% +to measure this performance and so then + + + align:start position:0% +to measure this performance and so then +it won't matter if our code runs on a + + align:start position:0% +it won't matter if our code runs on a + + + align:start position:0% +it won't matter if our code runs on a +fast machine or a slow machine if we can + + align:start position:0% +fast machine or a slow machine if we can + + + align:start position:0% +fast machine or a slow machine if we can +compare it with another piece of code or + + align:start position:0% +compare it with another piece of code or + + + align:start position:0% +compare it with another piece of code or +another variant of the code and say oh + + align:start position:0% +another variant of the code and say oh + + + align:start position:0% +another variant of the code and say oh +this new variant is slower or the new + + align:start position:0% +this new variant is slower or the new + + + align:start position:0% +this new variant is slower or the new +variant is faster according to this + + align:start position:0% +variant is faster according to this + + + align:start position:0% +variant is faster according to this +metric all right so without further ado + + align:start position:0% +metric all right so without further ado + + + align:start position:0% +metric all right so without further ado +let's dive into Sudoku how many of you + + align:start position:0% +let's dive into Sudoku how many of you + + + align:start position:0% +let's dive into Sudoku how many of you +have never seen Sudoku never played + + align:start position:0% +have never seen Sudoku never played + + + align:start position:0% +have never seen Sudoku never played +Sudoku all right so that's fine it's + + align:start position:0% +Sudoku all right so that's fine it's + + + align:start position:0% +Sudoku all right so that's fine it's +only going to take me about 30 seconds + + align:start position:0% +only going to take me about 30 seconds + + + align:start position:0% +only going to take me about 30 seconds +to explain what the rules of Sudoku are + + align:start position:0% +to explain what the rules of Sudoku are + + + align:start position:0% +to explain what the rules of Sudoku are +and then we can dive into trying to at + + align:start position:0% +and then we can dive into trying to at + + + align:start position:0% +and then we can dive into trying to at +least partially solve this puzzle + + align:start position:0% +least partially solve this puzzle + + + align:start position:0% +least partially solve this puzzle +III do not want to completely solve the + + align:start position:0% +III do not want to completely solve the + + + align:start position:0% +III do not want to completely solve the +puzzle because as I said you know I'm + + align:start position:0% +puzzle because as I said you know I'm + + + align:start position:0% +puzzle because as I said you know I'm +it's either too simple or it's too hard + + align:start position:0% +it's either too simple or it's too hard + + + align:start position:0% +it's either too simple or it's too hard +and I'd rather write computer programs + + align:start position:0% +and I'd rather write computer programs + + + align:start position:0% +and I'd rather write computer programs +and so so the rules of Sudoku are simple + + align:start position:0% +and so so the rules of Sudoku are simple + + + align:start position:0% +and so so the rules of Sudoku are simple +um so this is that classic Sudoku and + + align:start position:0% +um so this is that classic Sudoku and + + + align:start position:0% +um so this is that classic Sudoku and +it's 9 by 9 + + align:start position:0% +it's 9 by 9 + + + align:start position:0% +it's 9 by 9 +there's many variants of Sudoku in fact + + align:start position:0% +there's many variants of Sudoku in fact + + + align:start position:0% +there's many variants of Sudoku in fact +a couple of the exercises talk about two + + align:start position:0% +a couple of the exercises talk about two + + + align:start position:0% +a couple of the exercises talk about two +variants diagonal Sudoku and odd-even + + align:start position:0% +variants diagonal Sudoku and odd-even + + + align:start position:0% +variants diagonal Sudoku and odd-even +Sudoku I think there's probably odd + + align:start position:0% +Sudoku I think there's probably odd + + + align:start position:0% +Sudoku I think there's probably odd +Sudokus as well that add even more + + align:start position:0% +Sudokus as well that add even more + + + align:start position:0% +Sudokus as well that add even more +constraints to the basic constraints of + + align:start position:0% +constraints to the basic constraints of + + + align:start position:0% +constraints to the basic constraints of +Sudoku that I'm going to write up here + + align:start position:0% +Sudoku that I'm going to write up here + + + align:start position:0% +Sudoku that I'm going to write up here +and this is 9 by 9 Sudoku and the + + align:start position:0% +and this is 9 by 9 Sudoku and the + + + align:start position:0% +and this is 9 by 9 Sudoku and the +numbers are 1 through 9 + + align:start position:0% + + + + align:start position:0% + +and the rules are simple each row has + + align:start position:0% +and the rules are simple each row has + + + align:start position:0% +and the rules are simple each row has +all the numbers which means that no + + align:start position:0% +all the numbers which means that no + + + align:start position:0% +all the numbers which means that no +numbers could be repeated because this + + align:start position:0% +numbers could be repeated because this + + + align:start position:0% +numbers could be repeated because this +there's nine columns and nine rows so + + align:start position:0% +there's nine columns and nine rows so + + + align:start position:0% +there's nine columns and nine rows so +there's nine numbers on each row each + + align:start position:0% +there's nine numbers on each row each + + + align:start position:0% +there's nine numbers on each row each +column has all the numbers same thing so + + align:start position:0% +column has all the numbers same thing so + + + align:start position:0% +column has all the numbers same thing so +there's nine rows and nine columns and + + align:start position:0% +there's nine rows and nine columns and + + + align:start position:0% +there's nine rows and nine columns and +then each sector which is at three by + + align:start position:0% +then each sector which is at three by + + + align:start position:0% +then each sector which is at three by +three grid and so that's why I have + + align:start position:0% +three grid and so that's why I have + + + align:start position:0% +three grid and so that's why I have +these overhangs here corresponding to + + align:start position:0% +these overhangs here corresponding to + + + align:start position:0% +these overhangs here corresponding to +pointing out what the nine sectors are + + align:start position:0% +pointing out what the nine sectors are + + + align:start position:0% +pointing out what the nine sectors are +in Sudoku so this is a sector that's a + + align:start position:0% +in Sudoku so this is a sector that's a + + + align:start position:0% +in Sudoku so this is a sector that's a +sector this middle one which is + + align:start position:0% +sector this middle one which is + + + align:start position:0% +sector this middle one which is +completely blank right now is a sector + + align:start position:0% +completely blank right now is a sector + + + align:start position:0% +completely blank right now is a sector +etc so each sector has all the numbers + + align:start position:0% + + + + align:start position:0% + +you can grow the size of the puzzle it + + align:start position:0% +you can grow the size of the puzzle it + + + align:start position:0% +you can grow the size of the puzzle it +gets more difficult you could add more + + align:start position:0% +gets more difficult you could add more + + + align:start position:0% +gets more difficult you could add more +constraints as I mentioned diagonal + + align:start position:0% +constraints as I mentioned diagonal + + + align:start position:0% +constraints as I mentioned diagonal +Sudoku might say something like both of + + align:start position:0% +Sudoku might say something like both of + + + align:start position:0% +Sudoku might say something like both of +the diagonals the large diagonals the + + align:start position:0% +the diagonals the large diagonals the + + + align:start position:0% +the diagonals the large diagonals the +full-sized diagonals I have all nine + + align:start position:0% +full-sized diagonals I have all nine + + + align:start position:0% +full-sized diagonals I have all nine +numbers on them etc so that makes the + + align:start position:0% +numbers on them etc so that makes the + + + align:start position:0% +numbers on them etc so that makes the +puzzle different you may have a solution + + align:start position:0% +puzzle different you may have a solution + + + align:start position:0% +puzzle different you may have a solution +to the nine by nine original Sudoku + + align:start position:0% +to the nine by nine original Sudoku + + + align:start position:0% +to the nine by nine original Sudoku +puzzle but it may not be a solution to + + align:start position:0% +puzzle but it may not be a solution to + + + align:start position:0% +puzzle but it may not be a solution to +the diagonal a puzzle obviously the + + align:start position:0% +the diagonal a puzzle obviously the + + + align:start position:0% +the diagonal a puzzle obviously the +other way round works because the raggle + + align:start position:0% +other way round works because the raggle + + + align:start position:0% +other way round works because the raggle +puzzle only has more constraints and so + + align:start position:0% +puzzle only has more constraints and so + + + align:start position:0% +puzzle only has more constraints and so +what we do here is try and use + + align:start position:0% +what we do here is try and use + + + align:start position:0% +what we do here is try and use +implications right so we have these + + align:start position:0% +implications right so we have these + + + align:start position:0% +implications right so we have these +rules and that will first forget about + + align:start position:0% +rules and that will first forget about + + + align:start position:0% +rules and that will first forget about +computer programs and try and solve this + + align:start position:0% +computer programs and try and solve this + + + align:start position:0% +computer programs and try and solve this +by the way people do then they just have + + align:start position:0% +by the way people do then they just have + + + align:start position:0% +by the way people do then they just have +the paper and pencil and and they have a + + align:start position:0% +the paper and pencil and and they have a + + + align:start position:0% +the paper and pencil and and they have a +puzzle in front of them and they try and + + align:start position:0% +puzzle in front of them and they try and + + + align:start position:0% +puzzle in front of them and they try and +use these rules to discover empty + + align:start position:0% +use these rules to discover empty + + + align:start position:0% +use these rules to discover empty +positions and + + align:start position:0% +positions and + + + align:start position:0% +positions and +it's kind of hard to do anything with + + align:start position:0% +it's kind of hard to do anything with + + + align:start position:0% +it's kind of hard to do anything with +this sector here I'm you could use the + + align:start position:0% +this sector here I'm you could use the + + + align:start position:0% +this sector here I'm you could use the +row and column constraints obviously + + align:start position:0% +row and column constraints obviously + + + align:start position:0% +row and column constraints obviously +even for this sector because you have + + align:start position:0% +even for this sector because you have + + + align:start position:0% +even for this sector because you have +makan strains on these three based on + + align:start position:0% +makan strains on these three based on + + + align:start position:0% +makan strains on these three based on +the fact that you have nine and seven + + align:start position:0% +the fact that you have nine and seven + + + align:start position:0% +the fact that you have nine and seven +and one and six on this row etc but + + align:start position:0% +and one and six on this row etc but + + + align:start position:0% +and one and six on this row etc but +usually you go with sectors that have a + + align:start position:0% +usually you go with sectors that have a + + + align:start position:0% +usually you go with sectors that have a +few numbers in them you go with rows + + align:start position:0% +few numbers in them you go with rows + + + align:start position:0% +few numbers in them you go with rows +that have a few numbers in them and you + + align:start position:0% +that have a few numbers in them and you + + + align:start position:0% +that have a few numbers in them and you +go with columns that have a few numbers + + align:start position:0% +go with columns that have a few numbers + + + align:start position:0% +go with columns that have a few numbers +in them and then you can try and shrink + + align:start position:0% +in them and then you can try and shrink + + + align:start position:0% +in them and then you can try and shrink +the possibilities right so I just + + align:start position:0% +the possibilities right so I just + + + align:start position:0% +the possibilities right so I just +because I don't want to go overboard + + align:start position:0% +because I don't want to go overboard + + + align:start position:0% +because I don't want to go overboard +with respect to looking all over the + + align:start position:0% +with respect to looking all over the + + + align:start position:0% +with respect to looking all over the +puzzle let's focus in on on eight the + + align:start position:0% +puzzle let's focus in on on eight the + + + align:start position:0% +puzzle let's focus in on on eight the +number eight and one of you tell me if I + + align:start position:0% +number eight and one of you tell me if I + + + align:start position:0% +number eight and one of you tell me if I +can imply something based on the + + align:start position:0% +can imply something based on the + + + align:start position:0% +can imply something based on the +locations of eight on the top third of + + align:start position:0% +locations of eight on the top third of + + + align:start position:0% +locations of eight on the top third of +this puzzle right yeah go ahead top + + align:start position:0% +this puzzle right yeah go ahead top + + + align:start position:0% +this puzzle right yeah go ahead top +middle square what's your name + + align:start position:0% +middle square what's your name + + + align:start position:0% +middle square what's your name +kai so Kai says top middle square should + + align:start position:0% +kai so Kai says top middle square should + + + align:start position:0% +kai so Kai says top middle square should +be an eight right here right at the top + + align:start position:0% +be an eight right here right at the top + + + align:start position:0% +be an eight right here right at the top +okay yeah that clearly can be an eight + + align:start position:0% +okay yeah that clearly can be an eight + + + align:start position:0% +okay yeah that clearly can be an eight +because this is an eight here but good + + align:start position:0% +because this is an eight here but good + + + align:start position:0% +because this is an eight here but good +so so this this the claim as this is an + + align:start position:0% +so so this this the claim as this is an + + + align:start position:0% +so so this this the claim as this is an +eight and kai how did you figure that + + align:start position:0% +eight and kai how did you figure that + + + align:start position:0% +eight and kai how did you figure that +out it can't be here because of this + + align:start position:0% +out it can't be here because of this + + + align:start position:0% +out it can't be here because of this +eight it can be here because of this + + align:start position:0% +eight it can be here because of this + + + align:start position:0% +eight it can be here because of this +eight and you need to have an eight in + + align:start position:0% +eight and you need to have an eight in + + + align:start position:0% +eight and you need to have an eight in +here somewhere + + align:start position:0% +here somewhere + + + align:start position:0% +here somewhere +because it doesn't exist in this sector + + align:start position:0% +because it doesn't exist in this sector + + + align:start position:0% +because it doesn't exist in this sector +so that would imply that I need to put + + align:start position:0% +so that would imply that I need to put + + + align:start position:0% +so that would imply that I need to put +an eight up here okay so this is what's + + align:start position:0% +an eight up here okay so this is what's + + + align:start position:0% +an eight up here okay so this is what's +called a horizontal scan right the only + + align:start position:0% +called a horizontal scan right the only + + + align:start position:0% +called a horizontal scan right the only +thing that Qaeda here was scanned + + align:start position:0% +thing that Qaeda here was scanned + + + align:start position:0% +thing that Qaeda here was scanned +horizontally and you can imagine that so + + align:start position:0% +horizontally and you can imagine that so + + + align:start position:0% +horizontally and you can imagine that so +you do not a chi did not use in order to + + align:start position:0% +you do not a chi did not use in order to + + + align:start position:0% +you do not a chi did not use in order to +imply the eight and so this word + + align:start position:0% +imply the eight and so this word + + + align:start position:0% +imply the eight and so this word +implication imply is something that + + align:start position:0% +implication imply is something that + + + align:start position:0% +implication imply is something that +we're going to use in a more technical + + align:start position:0% +we're going to use in a more technical + + + align:start position:0% +we're going to use in a more technical +sense but as well when we write our code + + align:start position:0% +sense but as well when we write our code + + + align:start position:0% +sense but as well when we write our code +but an implication essentially says + + align:start position:0% +but an implication essentially says + + + align:start position:0% +but an implication essentially says +these rules imply the location of the + + align:start position:0% +these rules imply the location of the + + + align:start position:0% +these rules imply the location of the +eight right and a we didn't do a + + align:start position:0% +eight right and a we didn't do a + + + align:start position:0% +eight right and a we didn't do a +vertical scan we did not use the fact + + align:start position:0% +vertical scan we did not use the fact + + + align:start position:0% +vertical scan we did not use the fact +that in + + align:start position:0% +that in + + + align:start position:0% +that in +particular implication we did not use + + align:start position:0% +particular implication we did not use + + + align:start position:0% +particular implication we did not use +the fact that a column that needs to + + align:start position:0% +the fact that a column that needs to + + + align:start position:0% +the fact that a column that needs to +have all numbers on it and therefore all + + align:start position:0% +have all numbers on it and therefore all + + + align:start position:0% +have all numbers on it and therefore all +of the numbers on a column have to be + + align:start position:0% +of the numbers on a column have to be + + + align:start position:0% +of the numbers on a column have to be +unique all right take a look at take a + + align:start position:0% +unique all right take a look at take a + + + align:start position:0% +unique all right take a look at take a +look at this part here and let's look at + + align:start position:0% +look at this part here and let's look at + + + align:start position:0% +look at this part here and let's look at +let's look at one and try and use a more + + align:start position:0% +let's look at one and try and use a more + + + align:start position:0% +let's look at one and try and use a more +sophisticated form of implication + + align:start position:0% +sophisticated form of implication + + + align:start position:0% +sophisticated form of implication +corresponding to both horizontal and + + align:start position:0% +corresponding to both horizontal and + + + align:start position:0% +corresponding to both horizontal and +vertical scans to to imply the position + + align:start position:0% +vertical scans to to imply the position + + + align:start position:0% +vertical scans to to imply the position +of a one somewhere on the puzzle right + + align:start position:0% +of a one somewhere on the puzzle right + + + align:start position:0% +of a one somewhere on the puzzle right +can someone do that yeah back there okay + + align:start position:0% +can someone do that yeah back there okay + + + align:start position:0% +can someone do that yeah back there okay +so the one can't be here the one can't + + align:start position:0% +so the one can't be here the one can't + + + align:start position:0% +so the one can't be here the one can't +be here right and the one can't be here + + align:start position:0% +be here right and the one can't be here + + + align:start position:0% +be here right and the one can't be here +so it has to be over here right what's + + align:start position:0% +so it has to be over here right what's + + + align:start position:0% +so it has to be over here right what's +in it George + + align:start position:0% +in it George + + + align:start position:0% +in it George +so George says the one has to be here + + align:start position:0% +so George says the one has to be here + + + align:start position:0% +so George says the one has to be here +and he used both vertical scanning as + + align:start position:0% +and he used both vertical scanning as + + + align:start position:0% +and he used both vertical scanning as +well as horizontal scanning in order to + + align:start position:0% +well as horizontal scanning in order to + + + align:start position:0% +well as horizontal scanning in order to +imply the one so it's a little more + + align:start position:0% +imply the one so it's a little more + + + align:start position:0% +imply the one so it's a little more +sophisticated okay + + align:start position:0% +sophisticated okay + + + align:start position:0% +sophisticated okay +on top of that obviously sectors are + + align:start position:0% +on top of that obviously sectors are + + + align:start position:0% +on top of that obviously sectors are +going to give you some implications as + + align:start position:0% +going to give you some implications as + + + align:start position:0% +going to give you some implications as +well right and there's no end to this + + align:start position:0% +well right and there's no end to this + + + align:start position:0% +well right and there's no end to this +honestly there's combinations there's + + align:start position:0% +honestly there's combinations there's + + + align:start position:0% +honestly there's combinations there's +also a little bit of look ahead where + + align:start position:0% +also a little bit of look ahead where + + + align:start position:0% +also a little bit of look ahead where +the hardest puzzles are the ones where + + align:start position:0% +the hardest puzzles are the ones where + + + align:start position:0% +the hardest puzzles are the ones where +you run out of the eights and the ones + + align:start position:0% +you run out of the eights and the ones + + + align:start position:0% +you run out of the eights and the ones +in terms of the examples that we have + + align:start position:0% +in terms of the examples that we have + + + align:start position:0% +in terms of the examples that we have +here where we've just sort of implied + + align:start position:0% +here where we've just sort of implied + + + align:start position:0% +here where we've just sort of implied +without guessing + + align:start position:0% +without guessing + + + align:start position:0% +without guessing +we've implied the location of a number + + align:start position:0% +we've implied the location of a number + + + align:start position:0% +we've implied the location of a number +and then because of that our puzzle got + + align:start position:0% +and then because of that our puzzle got + + + align:start position:0% +and then because of that our puzzle got +smaller in the sense that there's fewer + + align:start position:0% +smaller in the sense that there's fewer + + + align:start position:0% +smaller in the sense that there's fewer +blank locations blank squares and then + + align:start position:0% +blank locations blank squares and then + + + align:start position:0% +blank locations blank squares and then +that helps us move forward right so the + + align:start position:0% +that helps us move forward right so the + + + align:start position:0% +that helps us move forward right so the +easy puzzles are the ones where fairly + + align:start position:0% +easy puzzles are the ones where fairly + + + align:start position:0% +easy puzzles are the ones where fairly +straightforward implications like the + + align:start position:0% +straightforward implications like the + + + align:start position:0% +straightforward implications like the +ones we did here always exist are easy + + align:start position:0% +ones we did here always exist are easy + + + align:start position:0% +ones we did here always exist are easy +to find you sometimes you have to search + + align:start position:0% +to find you sometimes you have to search + + + align:start position:0% +to find you sometimes you have to search +a little bit look at the top look at the + + align:start position:0% +a little bit look at the top look at the + + + align:start position:0% +a little bit look at the top look at the +power bottom look at the middle and and + + align:start position:0% +power bottom look at the middle and and + + + align:start position:0% +power bottom look at the middle and and +then you fill things in and because you + + align:start position:0% +then you fill things in and because you + + + align:start position:0% +then you fill things in and because you +filled things in something else now is + + align:start position:0% +filled things in something else now is + + + align:start position:0% +filled things in something else now is +in play right it becomes viable in terms + + align:start position:0% +in play right it becomes viable in terms + + + align:start position:0% +in play right it becomes viable in terms +of implication the fact that I put an + + align:start position:0% +of implication the fact that I put an + + + align:start position:0% +of implication the fact that I put an +aid in + + align:start position:0% +aid in + + + align:start position:0% +aid in +there I imply that the aid is now taken + + align:start position:0% +there I imply that the aid is now taken + + + align:start position:0% +there I imply that the aid is now taken +you know its location and so now + + align:start position:0% +you know its location and so now + + + align:start position:0% +you know its location and so now +obviously there's only four left here + + align:start position:0% +obviously there's only four left here + + + align:start position:0% +obviously there's only four left here +and the fact that it's an eight here + + align:start position:0% +and the fact that it's an eight here + + + align:start position:0% +and the fact that it's an eight here +implies that all of these can't have an + + align:start position:0% +implies that all of these can't have an + + + align:start position:0% +implies that all of these can't have an +eight in the these seven locations + + align:start position:0% +eight in the these seven locations + + + align:start position:0% +eight in the these seven locations +underneath can't have an eight in in + + align:start position:0% +underneath can't have an eight in in + + + align:start position:0% +underneath can't have an eight in in +them right because of their constraints + + align:start position:0% +them right because of their constraints + + + align:start position:0% +them right because of their constraints +so I'm this shrinking of possibilities + + align:start position:0% +so I'm this shrinking of possibilities + + + align:start position:0% +so I'm this shrinking of possibilities +it's something that a human does and you + + align:start position:0% +it's something that a human does and you + + + align:start position:0% +it's something that a human does and you +can kind of go through this process it's + + align:start position:0% +can kind of go through this process it's + + + align:start position:0% +can kind of go through this process it's +an iterative iterative process that you + + align:start position:0% +an iterative iterative process that you + + + align:start position:0% +an iterative iterative process that you +that you go through and you get stuck + + align:start position:0% +that you go through and you get stuck + + + align:start position:0% +that you go through and you get stuck +then you can't do an implication that + + align:start position:0% +then you can't do an implication that + + + align:start position:0% +then you can't do an implication that +gives you a number and some of the + + align:start position:0% +gives you a number and some of the + + + align:start position:0% +gives you a number and some of the +harder puzzles you have to you have a + + align:start position:0% +harder puzzles you have to you have a + + + align:start position:0% +harder puzzles you have to you have a +couple of choices and only one of them + + align:start position:0% +couple of choices and only one of them + + + align:start position:0% +couple of choices and only one of them +is going to be a correct one going + + align:start position:0% +is going to be a correct one going + + + align:start position:0% +is going to be a correct one going +forward but you don't know that at the + + align:start position:0% +forward but you don't know that at the + + + align:start position:0% +forward but you don't know that at the +moment at that moment so you don't have + + align:start position:0% +moment at that moment so you don't have + + + align:start position:0% +moment at that moment so you don't have +to can't guess and perhaps you put in an + + align:start position:0% +to can't guess and perhaps you put in an + + + align:start position:0% +to can't guess and perhaps you put in an +eight over here or Nate over there and + + align:start position:0% +eight over here or Nate over there and + + + align:start position:0% +eight over here or Nate over there and +then you say I'm gonna go with an eight + + align:start position:0% +then you say I'm gonna go with an eight + + + align:start position:0% +then you say I'm gonna go with an eight +over here and then you go a little bit + + align:start position:0% +over here and then you go a little bit + + + align:start position:0% +over here and then you go a little bit +further and then you realize wait a + + align:start position:0% +further and then you realize wait a + + + align:start position:0% +further and then you realize wait a +minute you know there's no way I can + + align:start position:0% +minute you know there's no way I can + + + align:start position:0% +minute you know there's no way I can +solve this puzzle because I need to put + + align:start position:0% +solve this puzzle because I need to put + + + align:start position:0% +solve this puzzle because I need to put +two sevens into the sector and then you + + align:start position:0% +two sevens into the sector and then you + + + align:start position:0% +two sevens into the sector and then you +go back and there's actually a bit of + + align:start position:0% +go back and there's actually a bit of + + + align:start position:0% +go back and there's actually a bit of +backtracking that happens at the wrong + + align:start position:0% +backtracking that happens at the wrong + + + align:start position:0% +backtracking that happens at the wrong +guess and you need to go backwards and + + align:start position:0% +guess and you need to go backwards and + + + align:start position:0% +guess and you need to go backwards and +it's very hard to do for us it's very + + align:start position:0% +it's very hard to do for us it's very + + + align:start position:0% +it's very hard to do for us it's very +hard to do for us with pencil and paper + + align:start position:0% +hard to do for us with pencil and paper + + + align:start position:0% +hard to do for us with pencil and paper +keeping things in our head or you know + + align:start position:0% +keeping things in our head or you know + + + align:start position:0% +keeping things in our head or you know +writing down notes on the side of the + + align:start position:0% +writing down notes on the side of the + + + align:start position:0% +writing down notes on the side of the +paper whereas it's very easy to do that + + align:start position:0% +paper whereas it's very easy to do that + + + align:start position:0% +paper whereas it's very easy to do that +for a computer program right and we kind + + align:start position:0% +for a computer program right and we kind + + + align:start position:0% +for a computer program right and we kind +of did that already in the in the eight + + align:start position:0% +of did that already in the in the eight + + + align:start position:0% +of did that already in the in the eight +Queens but we're gonna do that in a much + + align:start position:0% +Queens but we're gonna do that in a much + + + align:start position:0% +Queens but we're gonna do that in a much +more systematic way over here right so + + align:start position:0% +more systematic way over here right so + + + align:start position:0% +more systematic way over here right so +you kind of way these two ways of + + align:start position:0% +you kind of way these two ways of + + + align:start position:0% +you kind of way these two ways of +approaching this problem one of which is + + align:start position:0% +approaching this problem one of which is + + + align:start position:0% +approaching this problem one of which is +I'm just going to blast through the + + align:start position:0% +I'm just going to blast through the + + + align:start position:0% +I'm just going to blast through the +different combinations having a giant + + align:start position:0% +different combinations having a giant + + + align:start position:0% +different combinations having a giant +tree structure in my head where you know + + align:start position:0% +tree structure in my head where you know + + + align:start position:0% +tree structure in my head where you know +this this might imply that particular + + align:start position:0% +this this might imply that particular + + + align:start position:0% +this this might imply that particular +grid location a grid IJ equals 8 + + align:start position:0% +grid location a grid IJ equals 8 + + + align:start position:0% +grid location a grid IJ equals 8 +this might imply that grid IJ equals 7 + + align:start position:0% +this might imply that grid IJ equals 7 + + + align:start position:0% +this might imply that grid IJ equals 7 +and you know there's obviously a huge + + align:start position:0% +and you know there's obviously a huge + + + align:start position:0% +and you know there's obviously a huge +number of combinations corresponding to + + align:start position:0% +number of combinations corresponding to + + + align:start position:0% +number of combinations corresponding to +which of these squares that I pick and + + align:start position:0% +which of these squares that I pick and + + + align:start position:0% +which of these squares that I pick and +what value I assign to those squares and + + align:start position:0% +what value I assign to those squares and + + + align:start position:0% +what value I assign to those squares and +then once I do that there's another set + + align:start position:0% +then once I do that there's another set + + + align:start position:0% +then once I do that there's another set +and this + + align:start position:0% +and this + + + align:start position:0% +and this +clothes on you very quickly and so if + + align:start position:0% +clothes on you very quickly and so if + + + align:start position:0% +clothes on you very quickly and so if +you just did this in a completely + + align:start position:0% +you just did this in a completely + + + align:start position:0% +you just did this in a completely +brutish way there's no way your program + + align:start position:0% +brutish way there's no way your program + + + align:start position:0% +brutish way there's no way your program +would ever end even on a simple puzzle + + align:start position:0% +would ever end even on a simple puzzle + + + align:start position:0% +would ever end even on a simple puzzle +but thanks to these rules it turns out a + + align:start position:0% +but thanks to these rules it turns out a + + + align:start position:0% +but thanks to these rules it turns out a +fairly straightforward program that's 20 + + align:start position:0% +fairly straightforward program that's 20 + + + align:start position:0% +fairly straightforward program that's 20 +lines of code is going to solve most + + align:start position:0% +lines of code is going to solve most + + + align:start position:0% +lines of code is going to solve most +problems at least the ones that I've + + align:start position:0% +problems at least the ones that I've + + + align:start position:0% +problems at least the ones that I've +looked at in in a reasonable amount of + + align:start position:0% +looked at in in a reasonable amount of + + + align:start position:0% +looked at in in a reasonable amount of +time and and then you know it's just + + align:start position:0% +time and and then you know it's just + + + align:start position:0% +time and and then you know it's just +interesting from an algorithmic + + align:start position:0% +interesting from an algorithmic + + + align:start position:0% +interesting from an algorithmic +standpoint and a and an efficiency + + align:start position:0% +standpoint and a and an efficiency + + + align:start position:0% +standpoint and a and an efficiency +standpoint to look and see how we can + + align:start position:0% +standpoint to look and see how we can + + + align:start position:0% +standpoint to look and see how we can +take that fairly naive approach which + + align:start position:0% +take that fairly naive approach which + + + align:start position:0% +take that fairly naive approach which +does have some pruning but it's it's + + align:start position:0% +does have some pruning but it's it's + + + align:start position:0% +does have some pruning but it's it's +exhaustive and improve that all right so + + align:start position:0% +exhaustive and improve that all right so + + + align:start position:0% +exhaustive and improve that all right so +that's kind of where we're headed make + + align:start position:0% +that's kind of where we're headed make + + + align:start position:0% +that's kind of where we're headed make +sense + + align:start position:0% +sense + + + align:start position:0% +sense +any any questions about what we have so + + align:start position:0% +any any questions about what we have so + + + align:start position:0% +any any questions about what we have so +far all right so what we're going to do + + align:start position:0% +far all right so what we're going to do + + + align:start position:0% +far all right so what we're going to do +is go ahead and and and look at at code + + align:start position:0% +is go ahead and and and look at at code + + + align:start position:0% +is go ahead and and and look at at code +for Sudoku that it's of all you need to + + align:start position:0% +for Sudoku that it's of all you need to + + + align:start position:0% +for Sudoku that it's of all you need to +think about now for the next few minutes + + align:start position:0% +think about now for the next few minutes + + + align:start position:0% +think about now for the next few minutes +because we're going to move into + + align:start position:0% +because we're going to move into + + + align:start position:0% +because we're going to move into +exhaustive search mode and code things + + align:start position:0% +exhaustive search mode and code things + + + align:start position:0% +exhaustive search mode and code things +up in a computer is just those rules so + + align:start position:0% +up in a computer is just those rules so + + + align:start position:0% +up in a computer is just those rules so +you don't have to really think about + + align:start position:0% +you don't have to really think about + + + align:start position:0% +you don't have to really think about +horizontal scans and implications or + + align:start position:0% +horizontal scans and implications or + + + align:start position:0% +horizontal scans and implications or +vertical scans you know that's going to + + align:start position:0% +vertical scans you know that's going to + + + align:start position:0% +vertical scans you know that's going to +come a little bit later and we're going + + align:start position:0% +come a little bit later and we're going + + + align:start position:0% +come a little bit later and we're going +to bury that up as well but we're going + + align:start position:0% +to bury that up as well but we're going + + + align:start position:0% +to bury that up as well but we're going +to do kind of what we did for the + + align:start position:0% +to do kind of what we did for the + + + align:start position:0% +to do kind of what we did for the +n-queens problem which is set up + + align:start position:0% +n-queens problem which is set up + + + align:start position:0% +n-queens problem which is set up +recursive search that is going to + + align:start position:0% +recursive search that is going to + + + align:start position:0% +recursive search that is going to +explore all of these different + + align:start position:0% +explore all of these different + + + align:start position:0% +explore all of these different +possibilities and the equivalent of no + + align:start position:0% +possibilities and the equivalent of no + + + align:start position:0% +possibilities and the equivalent of no +conflicts for for the a queen so the N + + align:start position:0% +conflicts for for the a queen so the N + + + align:start position:0% +conflicts for for the a queen so the N +Queens problem which said there's no + + align:start position:0% +Queens problem which said there's no + + + align:start position:0% +Queens problem which said there's no +conflicts here I because none of the + + align:start position:0% +conflicts here I because none of the + + + align:start position:0% +conflicts here I because none of the +Queen's attack each other we're going to + + align:start position:0% +Queen's attack each other we're going to + + + align:start position:0% +Queen's attack each other we're going to +have something that essentially says + + align:start position:0% +have something that essentially says + + + align:start position:0% +have something that essentially says +this is valid so far none of the rules + + align:start position:0% +this is valid so far none of the rules + + + align:start position:0% +this is valid so far none of the rules +of Sudoku corresponding to these three + + align:start position:0% +of Sudoku corresponding to these three + + + align:start position:0% +of Sudoku corresponding to these three +rules that I have up on the board are + + align:start position:0% +rules that I have up on the board are + + + align:start position:0% +rules that I have up on the board are +going to be violated all right so let's + + align:start position:0% +going to be violated all right so let's + + + align:start position:0% +going to be violated all right so let's +take a look and so this structure + + align:start position:0% +take a look and so this structure + + + align:start position:0% +take a look and so this structure +hopefully given that we've done a n + + align:start position:0% +hopefully given that we've done a n + + + align:start position:0% +hopefully given that we've done a n +Queens I should be a little bit easier + + align:start position:0% +Queens I should be a little bit easier + + + align:start position:0% +Queens I should be a little bit easier +to understand so um + + align:start position:0% +to understand so um + + + align:start position:0% +to understand so um +when we did eight Queens or in Queens we + + align:start position:0% +when we did eight Queens or in Queens we + + + align:start position:0% +when we did eight Queens or in Queens we +decided to start column by column and we + + align:start position:0% +decided to start column by column and we + + + align:start position:0% +decided to start column by column and we +could have done row by row but we + + align:start position:0% +could have done row by row but we + + + align:start position:0% +could have done row by row but we +decided to start column by column and it + + align:start position:0% +decided to start column by column and it + + + align:start position:0% +decided to start column by column and it +was a fairly straightforward puzzle + + align:start position:0% +was a fairly straightforward puzzle + + + align:start position:0% +was a fairly straightforward puzzle +there's obviously no real change in an + + align:start position:0% +there's obviously no real change in an + + + align:start position:0% +there's obviously no real change in an +eight Queens puzzle I mean you're + + align:start position:0% +eight Queens puzzle I mean you're + + + align:start position:0% +eight Queens puzzle I mean you're +solving the same puzzle as I am but if I + + align:start position:0% +solving the same puzzle as I am but if I + + + align:start position:0% +solving the same puzzle as I am but if I +give you a pseudo puzzle there's more + + align:start position:0% +give you a pseudo puzzle there's more + + + align:start position:0% +give you a pseudo puzzle there's more +variety to it in the sense that + + align:start position:0% +variety to it in the sense that + + + align:start position:0% +variety to it in the sense that +depending on what I fill up the hard + + align:start position:0% +depending on what I fill up the hard + + + align:start position:0% +depending on what I fill up the hard +puzzles are the ones that are kind of + + align:start position:0% +puzzles are the ones that are kind of + + + align:start position:0% +puzzles are the ones that are kind of +intermediate in the sense of they're not + + align:start position:0% +intermediate in the sense of they're not + + + align:start position:0% +intermediate in the sense of they're not +obviously fully filled and they're not + + align:start position:0% +obviously fully filled and they're not + + + align:start position:0% +obviously fully filled and they're not +empty right if it's completely empty + + align:start position:0% +empty right if it's completely empty + + + align:start position:0% +empty right if it's completely empty +then it's it's trivial to solve a Sudoku + + align:start position:0% +then it's it's trivial to solve a Sudoku + + + align:start position:0% +then it's it's trivial to solve a Sudoku +puzzle you can take any solution to a + + align:start position:0% +puzzle you can take any solution to a + + + align:start position:0% +puzzle you can take any solution to a +Sudoku puzzle and present it as a + + align:start position:0% +Sudoku puzzle and present it as a + + + align:start position:0% +Sudoku puzzle and present it as a +solution to the empty puzzle and then if + + align:start position:0% +solution to the empty puzzle and then if + + + align:start position:0% +solution to the empty puzzle and then if +it's if it's everything is is full + + align:start position:0% +it's if it's everything is is full + + + align:start position:0% +it's if it's everything is is full +except for two things I mean it's kind + + align:start position:0% +except for two things I mean it's kind + + + align:start position:0% +except for two things I mean it's kind +of obvious what those two things are + + align:start position:0% +of obvious what those two things are + + + align:start position:0% +of obvious what those two things are +assuming that the puzzle had a valid + + align:start position:0% +assuming that the puzzle had a valid + + + align:start position:0% +assuming that the puzzle had a valid +solution + + align:start position:0% +solution + + + align:start position:0% +solution +so really it's it's puzzles like this + + align:start position:0% +so really it's it's puzzles like this + + + align:start position:0% +so really it's it's puzzles like this +where maybe a third are full that that + + align:start position:0% +where maybe a third are full that that + + + align:start position:0% +where maybe a third are full that that +that are more difficult right and it's + + align:start position:0% +that are more difficult right and it's + + + align:start position:0% +that are more difficult right and it's +kind of a separate school a little + + align:start position:0% +kind of a separate school a little + + + align:start position:0% +kind of a separate school a little +community that designs puzzles and tries + + align:start position:0% +community that designs puzzles and tries + + + align:start position:0% +community that designs puzzles and tries +to create hard puzzles and they try and + + align:start position:0% +to create hard puzzles and they try and + + + align:start position:0% +to create hard puzzles and they try and +make the humans hard + + align:start position:0% +make the humans hard + + + align:start position:0% +make the humans hard +I'm sorry humans problem harder by + + align:start position:0% +I'm sorry humans problem harder by + + + align:start position:0% +I'm sorry humans problem harder by +making this requirement of look-ahead + + align:start position:0% +making this requirement of look-ahead + + + align:start position:0% +making this requirement of look-ahead +like I mentioned right so good so let's + + align:start position:0% +like I mentioned right so good so let's + + + align:start position:0% +like I mentioned right so good so let's +take a look at the code here um so what + + align:start position:0% +take a look at the code here um so what + + + align:start position:0% +take a look at the code here um so what +I want to do here and the first part + + align:start position:0% +I want to do here and the first part + + + align:start position:0% +I want to do here and the first part +here is it is said that as I said we + + align:start position:0% +here is it is said that as I said we + + + align:start position:0% +here is it is said that as I said we +went column by column in the case of n + + align:start position:0% +went column by column in the case of n + + + align:start position:0% +went column by column in the case of n +queens and the question is where do I + + align:start position:0% +queens and the question is where do I + + + align:start position:0% +queens and the question is where do I +start I want to do something in a fairly + + align:start position:0% +start I want to do something in a fairly + + + align:start position:0% +start I want to do something in a fairly +naive way and what I'm going to do is + + align:start position:0% +naive way and what I'm going to do is + + + align:start position:0% +naive way and what I'm going to do is +I'm going to do some sort of scan you + + align:start position:0% +I'm going to do some sort of scan you + + + align:start position:0% +I'm going to do some sort of scan you +know I'm gonna scan like that and I'm + + align:start position:0% +know I'm gonna scan like that and I'm + + + align:start position:0% +know I'm gonna scan like that and I'm +going to find as I do the scan I'm going + + align:start position:0% +going to find as I do the scan I'm going + + + align:start position:0% +going to find as I do the scan I'm going +to find the the next empty grid location + + align:start position:0% +to find the the next empty grid location + + + align:start position:0% +to find the the next empty grid location +and I'm gonna say that is going to be + + align:start position:0% +and I'm gonna say that is going to be + + + align:start position:0% +and I'm gonna say that is going to be +something that I'm going to try and fill + + align:start position:0% +something that I'm going to try and fill + + + align:start position:0% +something that I'm going to try and fill +in okay so it's not going to be I + + align:start position:0% +in okay so it's not going to be I + + + align:start position:0% +in okay so it's not going to be I +discovered this H in the in the it was + + align:start position:0% +discovered this H in the in the it was + + + align:start position:0% +discovered this H in the in the it was +if you count in terms of the empty + + align:start position:0% +if you count in terms of the empty + + + align:start position:0% +if you count in terms of the empty +locations if I went this way it was the + + align:start position:0% +locations if I went this way it was the + + + align:start position:0% +locations if I went this way it was the +fourth empty location and decided to + + align:start position:0% +fourth empty location and decided to + + + align:start position:0% +fourth empty location and decided to +fill that up but here I'm just in this + + align:start position:0% +fill that up but here I'm just in this + + + align:start position:0% +fill that up but here I'm just in this +code I'm gonna try one two three four + + align:start position:0% +code I'm gonna try one two three four + + + align:start position:0% +code I'm gonna try one two three four +five six seven eight nine here and the + + align:start position:0% +five six seven eight nine here and the + + + align:start position:0% +five six seven eight nine here and the +first + + align:start position:0% +first + + + align:start position:0% +first +a part of the code here that says what + + align:start position:0% +a part of the code here that says what + + + align:start position:0% +a part of the code here that says what +is the name of this procedure it says + + align:start position:0% +is the name of this procedure it says + + + align:start position:0% +is the name of this procedure it says +fine next cell to fill you know but it + + align:start position:0% +fine next cell to fill you know but it + + + align:start position:0% +fine next cell to fill you know but it +means what it's name is find the next + + align:start position:0% +means what it's name is find the next + + + align:start position:0% +means what it's name is find the next +cell find the next weird location to + + align:start position:0% +cell find the next weird location to + + + align:start position:0% +cell find the next weird location to +fill and it simply goes for X and range + + align:start position:0% +fill and it simply goes for X and range + + + align:start position:0% +fill and it simply goes for X and range +0 through 9 for Y and range 0 through 9 + + align:start position:0% +0 through 9 for Y and range 0 through 9 + + + align:start position:0% +0 through 9 for Y and range 0 through 9 +I'm assuming that since 0 is not a valid + + align:start position:0% +I'm assuming that since 0 is not a valid + + + align:start position:0% +I'm assuming that since 0 is not a valid +entry here I could use 0 to signify + + align:start position:0% +entry here I could use 0 to signify + + + align:start position:0% +entry here I could use 0 to signify +empty ok it's only 1 through 9 so 0 can + + align:start position:0% +empty ok it's only 1 through 9 so 0 can + + + align:start position:0% +empty ok it's only 1 through 9 so 0 can +signify empty and this just returns x + + align:start position:0% +signify empty and this just returns x + + + align:start position:0% +signify empty and this just returns x +and y corresponding to the the first + + align:start position:0% +and y corresponding to the the first + + + align:start position:0% +and y corresponding to the the first +empty location so in this case it would + + align:start position:0% +empty location so in this case it would + + + align:start position:0% +empty location so in this case it would +just return 0 0 ok and then if this were + + align:start position:0% +just return 0 0 ok and then if this were + + + align:start position:0% +just return 0 0 ok and then if this were +full then it would go obviously it + + align:start position:0% +full then it would go obviously it + + + align:start position:0% +full then it would go obviously it +exchanges and when exchanges you're + + align:start position:0% +exchanges and when exchanges you're + + + align:start position:0% +exchanges and when exchanges you're +going over to the to the right and so + + align:start position:0% +going over to the to the right and so + + + align:start position:0% +going over to the to the right and so +you would get a 1 1 0 back if this were + + align:start position:0% +you would get a 1 1 0 back if this were + + + align:start position:0% +you would get a 1 1 0 back if this were +filled the next time around I'd get this + + align:start position:0% +filled the next time around I'd get this + + + align:start position:0% +filled the next time around I'd get this +grid location etc right it doesn't + + align:start position:0% +grid location etc right it doesn't + + + align:start position:0% +grid location etc right it doesn't +matter just like I could go column by + + align:start position:0% +matter just like I could go column by + + + align:start position:0% +matter just like I could go column by +column by row by row as long as I have a + + align:start position:0% +column by row by row as long as I have a + + + align:start position:0% +column by row by row as long as I have a +deterministic way of discovering the the + + align:start position:0% +deterministic way of discovering the the + + + align:start position:0% +deterministic way of discovering the the +empty location and usually you want to + + align:start position:0% +empty location and usually you want to + + + align:start position:0% +empty location and usually you want to +have it the same way of discovering the + + align:start position:0% +have it the same way of discovering the + + + align:start position:0% +have it the same way of discovering the +empty location but even that is not a + + align:start position:0% +empty location but even that is not a + + + align:start position:0% +empty location but even that is not a +requirement as long as there's an empty + + align:start position:0% +requirement as long as there's an empty + + + align:start position:0% +requirement as long as there's an empty +location and you're fine next cell to + + align:start position:0% +location and you're fine next cell to + + + align:start position:0% +location and you're fine next cell to +fill finds that empty location and + + align:start position:0% +fill finds that empty location and + + + align:start position:0% +fill finds that empty location and +returns it to you you're good and this + + align:start position:0% +returns it to you you're good and this + + + align:start position:0% +returns it to you you're good and this +the rest of our code is going to work + + align:start position:0% +the rest of our code is going to work + + + align:start position:0% +the rest of our code is going to work +right but no reason to get more + + align:start position:0% +right but no reason to get more + + + align:start position:0% +right but no reason to get more +complicated than what I have up there + + align:start position:0% +complicated than what I have up there + + + align:start position:0% +complicated than what I have up there +all right so fine next cell to fill make + + align:start position:0% +all right so fine next cell to fill make + + + align:start position:0% +all right so fine next cell to fill make +sense right good with that all right + + align:start position:0% +sense right good with that all right + + + align:start position:0% +sense right good with that all right +and the generally with exhaustive search + + align:start position:0% +and the generally with exhaustive search + + + align:start position:0% +and the generally with exhaustive search +I think the key procedure is always I do + + align:start position:0% +I think the key procedure is always I do + + + align:start position:0% +I think the key procedure is always I do +you have a valid solution or not and you + + align:start position:0% +you have a valid solution or not and you + + + align:start position:0% +you have a valid solution or not and you +may not have a complete solution think + + align:start position:0% +may not have a complete solution think + + + align:start position:0% +may not have a complete solution think +of it as a partial configuration right + + align:start position:0% +of it as a partial configuration right + + + align:start position:0% +of it as a partial configuration right +so this is a partial configuration and + + align:start position:0% +so this is a partial configuration and + + + align:start position:0% +so this is a partial configuration and +that is valid it's not a complete + + align:start position:0% +that is valid it's not a complete + + + align:start position:0% +that is valid it's not a complete +solution to the Sudoku puzzle it's a + + align:start position:0% +solution to the Sudoku puzzle it's a + + + align:start position:0% +solution to the Sudoku puzzle it's a +partial configuration that's valid in + + align:start position:0% +partial configuration that's valid in + + + align:start position:0% +partial configuration that's valid in +the sense that it satisfies all of the + + align:start position:0% +the sense that it satisfies all of the + + + align:start position:0% +the sense that it satisfies all of the +constraints you know if I put another + + align:start position:0% +constraints you know if I put another + + + align:start position:0% +constraints you know if I put another +aid in here it would not be a valid + + align:start position:0% +aid in here it would not be a valid + + + align:start position:0% +aid in here it would not be a valid +partial configuration it would be + + align:start position:0% +partial configuration it would be + + + align:start position:0% +partial configuration it would be +partial but not bad + + align:start position:0% +partial but not bad + + + align:start position:0% +partial but not bad +right and I need to grow this I need to + + align:start position:0% +right and I need to grow this I need to + + + align:start position:0% +right and I need to grow this I need to +grow this into a solution and when I say + + align:start position:0% +grow this into a solution and when I say + + + align:start position:0% +grow this into a solution and when I say +solution I mean all the constraints have + + align:start position:0% +solution I mean all the constraints have + + + align:start position:0% +solution I mean all the constraints have +to be satisfied right a configuration + + align:start position:0% +to be satisfied right a configuration + + + align:start position:0% +to be satisfied right a configuration +could be invalid or valid a solution is + + align:start position:0% +could be invalid or valid a solution is + + + align:start position:0% +could be invalid or valid a solution is +always valid all right that's just + + align:start position:0% +always valid all right that's just + + + align:start position:0% +always valid all right that's just +terminology and so I want to be able to + + align:start position:0% +terminology and so I want to be able to + + + align:start position:0% +terminology and so I want to be able to +to look high up and be able to truncate + + align:start position:0% +to look high up and be able to truncate + + + align:start position:0% +to look high up and be able to truncate +the search and say you know what grid IJ + + align:start position:0% +the search and say you know what grid IJ + + + align:start position:0% +the search and say you know what grid IJ +equaling eight because I put an 8 in + + align:start position:0% +equaling eight because I put an 8 in + + + align:start position:0% +equaling eight because I put an 8 in +that sector which already had an 8 in it + + align:start position:0% +that sector which already had an 8 in it + + + align:start position:0% +that sector which already had an 8 in it +is is something that should not be + + align:start position:0% +is is something that should not be + + + align:start position:0% +is is something that should not be +explored and I don't have to worry about + + align:start position:0% +explored and I don't have to worry about + + + align:start position:0% +explored and I don't have to worry about +any of the branches that come here + + align:start position:0% +any of the branches that come here + + + align:start position:0% +any of the branches that come here +because immediately I've violated the + + align:start position:0% +because immediately I've violated the + + + align:start position:0% +because immediately I've violated the +constraint right so in general I can + + align:start position:0% +constraint right so in general I can + + + align:start position:0% +constraint right so in general I can +always check where their partial + + align:start position:0% +always check where their partial + + + align:start position:0% +always check where their partial +configurations violate the three + + align:start position:0% +configurations violate the three + + + align:start position:0% +configurations violate the three +constraints I have or not right and that + + align:start position:0% +constraints I have or not right and that + + + align:start position:0% +constraints I have or not right and that +is what this piece of code does and it's + + align:start position:0% +is what this piece of code does and it's + + + align:start position:0% +is what this piece of code does and it's +also straightforward it perhaps even + + align:start position:0% +also straightforward it perhaps even + + + align:start position:0% +also straightforward it perhaps even +even more straightforward than diagonal + + align:start position:0% +even more straightforward than diagonal + + + align:start position:0% +even more straightforward than diagonal +checking in the case of eight Queens but + + align:start position:0% +checking in the case of eight Queens but + + + align:start position:0% +checking in the case of eight Queens but +all this does is use the construct that + + align:start position:0% +all this does is use the construct that + + + align:start position:0% +all this does is use the construct that +says I'm going to look at essentially + + align:start position:0% +says I'm going to look at essentially + + + align:start position:0% +says I'm going to look at essentially +this is something that is list + + align:start position:0% +this is something that is list + + + align:start position:0% +this is something that is list +comprehensions in in Python the four + + align:start position:0% +comprehensions in in Python the four + + + align:start position:0% +comprehensions in in Python the four +comes after this predicate here but + + align:start position:0% +comes after this predicate here but + + + align:start position:0% +comes after this predicate here but +effectively what you're saying is for X + + align:start position:0% +effectively what you're saying is for X + + + align:start position:0% +effectively what you're saying is for X +and range nine check that grid IX is not + + align:start position:0% +and range nine check that grid IX is not + + + align:start position:0% +and range nine check that grid IX is not +equal to e okay and you're just looking + + align:start position:0% +equal to e okay and you're just looking + + + align:start position:0% +equal to e okay and you're just looking +at e so it's valid grid IJ e takes the + + align:start position:0% +at e so it's valid grid IJ e takes the + + + align:start position:0% +at e so it's valid grid IJ e takes the +grid which looks like this one let's say + + align:start position:0% +grid which looks like this one let's say + + + align:start position:0% +grid which looks like this one let's say +and so it's got zeros in all of the + + align:start position:0% +and so it's got zeros in all of the + + + align:start position:0% +and so it's got zeros in all of the +empty places and it's got a bunch of + + align:start position:0% +empty places and it's got a bunch of + + + align:start position:0% +empty places and it's got a bunch of +nonzero entries in all of the places + + align:start position:0% +nonzero entries in all of the places + + + align:start position:0% +nonzero entries in all of the places +that you see here and in addition you + + align:start position:0% +that you see here and in addition you + + + align:start position:0% +that you see here and in addition you +have perhaps zero zero and let's call it + + align:start position:0% +have perhaps zero zero and let's call it + + + align:start position:0% +have perhaps zero zero and let's call it +one right and so so this is I and this + + align:start position:0% +one right and so so this is I and this + + + align:start position:0% +one right and so so this is I and this +is J and that is e okay + + align:start position:0% +is J and that is e okay + + + align:start position:0% +is J and that is e okay +and so let me write that out here I J + + align:start position:0% +and so let me write that out here I J + + + align:start position:0% +and so let me write that out here I J +and E where I is one zero I'm sorry I is + + align:start position:0% +and E where I is one zero I'm sorry I is + + + align:start position:0% +and E where I is one zero I'm sorry I is +zero + + align:start position:0% +zero + + + align:start position:0% +zero +J is 0 and E is 1 so that would mean + + align:start position:0% +J is 0 and E is 1 so that would mean + + + align:start position:0% +J is 0 and E is 1 so that would mean +putting a putting a 1 up here and that + + align:start position:0% +putting a putting a 1 up here and that + + + align:start position:0% +putting a putting a 1 up here and that +obviously is going to violate one of our + + align:start position:0% +obviously is going to violate one of our + + + align:start position:0% +obviously is going to violate one of our +constraints but that's fine we gonna + + align:start position:0% +constraints but that's fine we gonna + + + align:start position:0% +constraints but that's fine we gonna +check that and it's essentially doing + + align:start position:0% +check that and it's essentially doing + + + align:start position:0% +check that and it's essentially doing +incremental checking just like we did so + + align:start position:0% +incremental checking just like we did so + + + align:start position:0% +incremental checking just like we did so +it's not checking to see that that all + + align:start position:0% +it's not checking to see that that all + + + align:start position:0% +it's not checking to see that that all +of the existing grid IJ values are + + align:start position:0% +of the existing grid IJ values are + + + align:start position:0% +of the existing grid IJ values are +conflicting or not it's just saying I'm + + align:start position:0% +conflicting or not it's just saying I'm + + + align:start position:0% +conflicting or not it's just saying I'm +having I'm gonna be writing something + + align:start position:0% +having I'm gonna be writing something + + + align:start position:0% +having I'm gonna be writing something +into this grid into an empty location it + + align:start position:0% +into this grid into an empty location it + + + align:start position:0% +into this grid into an empty location it +happens to be 0 0 having the value 1 and + + align:start position:0% +happens to be 0 0 having the value 1 and + + + align:start position:0% +happens to be 0 0 having the value 1 and +I'm going to check whether the + + align:start position:0% +I'm going to check whether the + + + align:start position:0% +I'm going to check whether the +introduction of a 1 into this square is + + align:start position:0% +introduction of a 1 into this square is + + + align:start position:0% +introduction of a 1 into this square is +going to cause problems or not right + + align:start position:0% +going to cause problems or not right + + + align:start position:0% +going to cause problems or not right +that's all it's that is doing right + + align:start position:0% +that's all it's that is doing right + + + align:start position:0% +that's all it's that is doing right +incremental just like we had with with 8 + + align:start position:0% +incremental just like we had with with 8 + + + align:start position:0% +incremental just like we had with with 8 +Queens and that check is relatively easy + + align:start position:0% +Queens and that check is relatively easy + + + align:start position:0% +Queens and that check is relatively easy +to do because I just need to go and I + + align:start position:0% +to do because I just need to go and I + + + align:start position:0% +to do because I just need to go and I +look at the row corresponding to 2 I win + + align:start position:0% +look at the row corresponding to 2 I win + + + align:start position:0% +look at the row corresponding to 2 I win +this case is the top row I look at the + + align:start position:0% +this case is the top row I look at the + + + align:start position:0% +this case is the top row I look at the +column corresponding to J which is the + + align:start position:0% +column corresponding to J which is the + + + align:start position:0% +column corresponding to J which is the +leftmost column and then I look at the + + align:start position:0% +leftmost column and then I look at the + + + align:start position:0% +leftmost column and then I look at the +sector corresponding to 0 0 which is + + align:start position:0% +sector corresponding to 0 0 which is + + + align:start position:0% +sector corresponding to 0 0 which is +this top left sector and I check to see + + align:start position:0% +this top left sector and I check to see + + + align:start position:0% +this top left sector and I check to see +for each of those three things whether + + align:start position:0% +for each of those three things whether + + + align:start position:0% +for each of those three things whether +there's a problem or not and the first + + align:start position:0% +there's a problem or not and the first + + + align:start position:0% +there's a problem or not and the first +two well actually I have a problem with + + align:start position:0% +two well actually I have a problem with + + + align:start position:0% +two well actually I have a problem with +the with the row and I would also have a + + align:start position:0% +the with the row and I would also have a + + + align:start position:0% +the with the row and I would also have a +problem with the with the sector I + + align:start position:0% +problem with the with the sector I + + + align:start position:0% +problem with the with the sector I +wouldn't have a problem with the with + + align:start position:0% +wouldn't have a problem with the with + + + align:start position:0% +wouldn't have a problem with the with +the column but in one of them is bad + + align:start position:0% +the column but in one of them is bad + + + align:start position:0% +the column but in one of them is bad +enough and so I'm gonna get a false back + + align:start position:0% +enough and so I'm gonna get a false back + + + align:start position:0% +enough and so I'm gonna get a false back +so row ok is going to be false and so I + + align:start position:0% +so row ok is going to be false and so I + + + align:start position:0% +so row ok is going to be false and so I +am going to return false out here + + align:start position:0% +am going to return false out here + + + align:start position:0% +am going to return false out here +alright that makes sense so those are + + align:start position:0% +alright that makes sense so those are + + + align:start position:0% +alright that makes sense so those are +the three things and this there's really + + align:start position:0% +the three things and this there's really + + + align:start position:0% +the three things and this there's really +not that much here beyond taking those + + align:start position:0% +not that much here beyond taking those + + + align:start position:0% +not that much here beyond taking those +constraints and and codifying them right + + align:start position:0% +constraints and and codifying them right + + + align:start position:0% +constraints and and codifying them right +any questions yeah Fadi + + align:start position:0% + + + + align:start position:0% + +all is essentially a Python built-in + + align:start position:0% +all is essentially a Python built-in + + + align:start position:0% +all is essentially a Python built-in +function that is going to essentially + + align:start position:0% +function that is going to essentially + + + align:start position:0% +function that is going to essentially +say that it's going to its it's a + + align:start position:0% +say that it's going to its it's a + + + align:start position:0% +say that it's going to its it's a +conjunction that says I'm getting a + + align:start position:0% +conjunction that says I'm getting a + + + align:start position:0% +conjunction that says I'm getting a +bunch of boolean s-- that correspond to + + align:start position:0% +bunch of boolean s-- that correspond to + + + align:start position:0% +bunch of boolean s-- that correspond to +the generation of this list + + align:start position:0% +the generation of this list + + + align:start position:0% +the generation of this list +comprehension where'd he not equal to + + align:start position:0% +comprehension where'd he not equal to + + + align:start position:0% +comprehension where'd he not equal to +grid IX is it's going to give me true or + + align:start position:0% +grid IX is it's going to give me true or + + + align:start position:0% +grid IX is it's going to give me true or +false and I need all of those things to + + align:start position:0% +false and I need all of those things to + + + align:start position:0% +false and I need all of those things to +be true all right yeah even if one of + + align:start position:0% +be true all right yeah even if one of + + + align:start position:0% +be true all right yeah even if one of +them is false the end is false in order + + align:start position:0% +them is false the end is false in order + + + align:start position:0% +them is false the end is false in order +for the end to be true then all of them + + align:start position:0% +for the end to be true then all of them + + + align:start position:0% +for the end to be true then all of them +need to be true all right so it's it's + + align:start position:0% +need to be true all right so it's it's + + + align:start position:0% +need to be true all right so it's it's +just a convenient construct which is + + align:start position:0% +just a convenient construct which is + + + align:start position:0% +just a convenient construct which is +applicable in a in in sort of a perfect + + align:start position:0% +applicable in a in in sort of a perfect + + + align:start position:0% +applicable in a in in sort of a perfect +the perfect application is what you see + + align:start position:0% +the perfect application is what you see + + + align:start position:0% +the perfect application is what you see +here it's not the most sophisticated of + + align:start position:0% +here it's not the most sophisticated of + + + align:start position:0% +here it's not the most sophisticated of +applications but it works very well in + + align:start position:0% +applications but it works very well in + + + align:start position:0% +applications but it works very well in +this case now for the sector I can't + + align:start position:0% +this case now for the sector I can't + + + align:start position:0% +this case now for the sector I can't +actually do that and so it is a little + + align:start position:0% +actually do that and so it is a little + + + align:start position:0% +actually do that and so it is a little +bit more work because I kind at this + + align:start position:0% +bit more work because I kind at this + + + align:start position:0% +bit more work because I kind at this +this only works when I could put a list + + align:start position:0% +this only works when I could put a list + + + align:start position:0% +this only works when I could put a list +comprehension in here like this and + + align:start position:0% +comprehension in here like this and + + + align:start position:0% +comprehension in here like this and +generate all the boolean x' for the + + align:start position:0% +generate all the boolean x' for the + + + align:start position:0% +generate all the boolean x' for the +sector I end up having to do something a + + align:start position:0% +sector I end up having to do something a + + + align:start position:0% +sector I end up having to do something a +little bit different I mean you could do + + align:start position:0% +little bit different I mean you could do + + + align:start position:0% +little bit different I mean you could do +things more convoluted than and use all + + align:start position:0% +things more convoluted than and use all + + + align:start position:0% +things more convoluted than and use all +in here as well but it's not worth it + + align:start position:0% +in here as well but it's not worth it + + + align:start position:0% +in here as well but it's not worth it +all right okay that makes sense good so + + align:start position:0% +all right okay that makes sense good so + + + align:start position:0% +all right okay that makes sense good so +here's the the core routine that + + align:start position:0% +here's the the core routine that + + + align:start position:0% +here's the the core routine that +corresponds to the search and ignored + + align:start position:0% +corresponds to the search and ignored + + + align:start position:0% +corresponds to the search and ignored +this global variable here I'll explain + + align:start position:0% +this global variable here I'll explain + + + align:start position:0% +this global variable here I'll explain +that in a minute + + align:start position:0% +that in a minute + + + align:start position:0% +that in a minute +it's that's going to be our metric our + + align:start position:0% +it's that's going to be our metric our + + + align:start position:0% +it's that's going to be our metric our +backtracks is going to be our metric for + + align:start position:0% +backtracks is going to be our metric for + + + align:start position:0% +backtracks is going to be our metric for +computing performance and it's going to + + align:start position:0% +computing performance and it's going to + + + align:start position:0% +computing performance and it's going to +be quite interesting it's going to + + align:start position:0% +be quite interesting it's going to + + + align:start position:0% +be quite interesting it's going to +produce some interesting results for us + + align:start position:0% +produce some interesting results for us + + + align:start position:0% +produce some interesting results for us +okay and then we run this on various + + align:start position:0% +okay and then we run this on various + + + align:start position:0% +okay and then we run this on various +different examples and but but this this + + align:start position:0% +different examples and but but this this + + + align:start position:0% +different examples and but but this this +core a procedure looks a lot like the + + align:start position:0% +core a procedure looks a lot like the + + + align:start position:0% +core a procedure looks a lot like the +n-queens search in the sense that you + + align:start position:0% +n-queens search in the sense that you + + + align:start position:0% +n-queens search in the sense that you +have a for loop and a recursive call + + align:start position:0% +have a for loop and a recursive call + + + align:start position:0% +have a for loop and a recursive call +okay and in this case you + + align:start position:0% +okay and in this case you + + + align:start position:0% +okay and in this case you +the the the for loop is going to be + + align:start position:0% +the the the for loop is going to be + + + align:start position:0% +the the the for loop is going to be +something that ranges through the + + align:start position:0% +something that ranges through the + + + align:start position:0% +something that ranges through the +different values that you find the + + align:start position:0% +different values that you find the + + + align:start position:0% +different values that you find the +location that you want to to put + + align:start position:0% +location that you want to to put + + + align:start position:0% +location that you want to to put +something into which is the the next + + align:start position:0% +something into which is the the next + + + align:start position:0% +something into which is the the next +empty location in your current + + align:start position:0% +empty location in your current + + + align:start position:0% +empty location in your current +configuration and then you need to go + + align:start position:0% +configuration and then you need to go + + + align:start position:0% +configuration and then you need to go +put in one through nine in there and + + align:start position:0% +put in one through nine in there and + + + align:start position:0% +put in one through nine in there and +it's is brutish you're going to put in + + align:start position:0% +it's is brutish you're going to put in + + + align:start position:0% +it's is brutish you're going to put in +one and you're gonna check conflicts and + + align:start position:0% +one and you're gonna check conflicts and + + + align:start position:0% +one and you're gonna check conflicts and +and then you'll put in two and you're + + align:start position:0% +and then you'll put in two and you're + + + align:start position:0% +and then you'll put in two and you're +gonna check conflicts if you put in a + + align:start position:0% +gonna check conflicts if you put in a + + + align:start position:0% +gonna check conflicts if you put in a +one and you don't get a conflict then + + align:start position:0% +one and you don't get a conflict then + + + align:start position:0% +one and you don't get a conflict then +you get to recur and you now move into + + align:start position:0% +you get to recur and you now move into + + + align:start position:0% +you get to recur and you now move into +something that is a another partial + + align:start position:0% +something that is a another partial + + + align:start position:0% +something that is a another partial +configuration potentially but but but + + align:start position:0% +configuration potentially but but but + + + align:start position:0% +configuration potentially but but but +obviously has one location filled from + + align:start position:0% +obviously has one location filled from + + + align:start position:0% +obviously has one location filled from +the from the caller configuration and + + align:start position:0% +the from the caller configuration and + + + align:start position:0% +the from the caller configuration and +then you go look for the next cell so + + align:start position:0% +then you go look for the next cell so + + + align:start position:0% +then you go look for the next cell so +it's certainly possible that I'd go if + + align:start position:0% +it's certainly possible that I'd go if + + + align:start position:0% +it's certainly possible that I'd go if +when I put in a 1 here that fails but if + + align:start position:0% +when I put in a 1 here that fails but if + + + align:start position:0% +when I put in a 1 here that fails but if +I put in a 2 here I it's not gonna fail + + align:start position:0% +I put in a 2 here I it's not gonna fail + + + align:start position:0% +I put in a 2 here I it's not gonna fail +2 is not gonna fail here because if I + + align:start position:0% +2 is not gonna fail here because if I + + + align:start position:0% +2 is not gonna fail here because if I +just look at those constraints at 2 is + + align:start position:0% +just look at those constraints at 2 is + + + align:start position:0% +just look at those constraints at 2 is +okay alright so I'm gonna put in a 2 + + align:start position:0% +okay alright so I'm gonna put in a 2 + + + align:start position:0% +okay alright so I'm gonna put in a 2 +here and then I'm going to recur and I'm + + align:start position:0% +here and then I'm going to recur and I'm + + + align:start position:0% +here and then I'm going to recur and I'm +gonna go out here and I'll try and put + + align:start position:0% +gonna go out here and I'll try and put + + + align:start position:0% +gonna go out here and I'll try and put +in a 1 here and a 1 is gonna fail + + align:start position:0% +in a 1 here and a 1 is gonna fail + + + align:start position:0% +in a 1 here and a 1 is gonna fail +because of this and that a 2 is gonna + + align:start position:0% +because of this and that a 2 is gonna + + + align:start position:0% +because of this and that a 2 is gonna +fail because of that I'm at 3 is a 3 + + align:start position:0% +fail because of that I'm at 3 is a 3 + + + align:start position:0% +fail because of that I'm at 3 is a 3 +gonna fail no not immediately so I could + + align:start position:0% +gonna fail no not immediately so I could + + + align:start position:0% +gonna fail no not immediately so I could +put in a 3 here and then I recurred and + + align:start position:0% +put in a 3 here and then I recurred and + + + align:start position:0% +put in a 3 here and then I recurred and +go to the next one and so on and so + + align:start position:0% +go to the next one and so on and so + + + align:start position:0% +go to the next one and so on and so +forth right and for at each of these + + align:start position:0% +forth right and for at each of these + + + align:start position:0% +forth right and for at each of these +things obviously I have to do a bunch of + + align:start position:0% +things obviously I have to do a bunch of + + + align:start position:0% +things obviously I have to do a bunch of +search underneath and that you know + + align:start position:0% +search underneath and that you know + + + align:start position:0% +search underneath and that you know +thank goodness for fast computers right + + align:start position:0% +thank goodness for fast computers right + + + align:start position:0% +thank goodness for fast computers right +because that's why some in God I mean + + align:start position:0% +because that's why some in God I mean + + + align:start position:0% +because that's why some in God I mean +can you imagine the amount of paper we + + align:start position:0% +can you imagine the amount of paper we + + + align:start position:0% +can you imagine the amount of paper we +generate if you were doing this and + + align:start position:0% +generate if you were doing this and + + + align:start position:0% +generate if you were doing this and +putting two and three and I want a new + + align:start position:0% +putting two and three and I want a new + + + align:start position:0% +putting two and three and I want a new +sheet of paper for the four etc etc I + + align:start position:0% +sheet of paper for the four etc etc I + + + align:start position:0% +sheet of paper for the four etc etc I +mean we can count the number of back + + align:start position:0% +mean we can count the number of back + + + align:start position:0% +mean we can count the number of back +tracks that's how many sheets of paper + + align:start position:0% +tracks that's how many sheets of paper + + + align:start position:0% +tracks that's how many sheets of paper +you'll need okay so so what you see here + + align:start position:0% +you'll need okay so so what you see here + + + align:start position:0% +you'll need okay so so what you see here +I again ignore the back tracks I'll get + + align:start position:0% +I again ignore the back tracks I'll get + + + align:start position:0% +I again ignore the back tracks I'll get +to that in just a second it's just a way + + align:start position:0% +to that in just a second it's just a way + + + align:start position:0% +to that in just a second it's just a way +of counting the number of calls and this + + align:start position:0% +of counting the number of calls and this + + + align:start position:0% +of counting the number of calls and this +thing here essentially says you know if + + align:start position:0% +thing here essentially says you know if + + + align:start position:0% +thing here essentially says you know if +I'm going to be + + align:start position:0% +I'm going to be + + + align:start position:0% +I'm going to be +turning I'm gonna if as long as I get + + align:start position:0% +turning I'm gonna if as long as I get + + + align:start position:0% +turning I'm gonna if as long as I get +through and find a solution I want to + + align:start position:0% +through and find a solution I want to + + + align:start position:0% +through and find a solution I want to +return true right so if solve Sudoku + + align:start position:0% +return true right so if solve Sudoku + + + align:start position:0% +return true right so if solve Sudoku +grid IJ is true then I'm going to return + + align:start position:0% +grid IJ is true then I'm going to return + + + align:start position:0% +grid IJ is true then I'm going to return +true and then I'm going to pop up all + + align:start position:0% +true and then I'm going to pop up all + + + align:start position:0% +true and then I'm going to pop up all +the way into the top assuming I got I go + + align:start position:0% +the way into the top assuming I got I go + + + align:start position:0% +the way into the top assuming I got I go +all the way down to the bottom and I get + + align:start position:0% +all the way down to the bottom and I get + + + align:start position:0% +all the way down to the bottom and I get +to the point where I have a solution + + align:start position:0% +to the point where I have a solution + + + align:start position:0% +to the point where I have a solution +that returns true which is a completely + + align:start position:0% +that returns true which is a completely + + + align:start position:0% +that returns true which is a completely +full configuration that returns true + + align:start position:0% +full configuration that returns true + + + align:start position:0% +full configuration that returns true +right but if not then I need to go a try + + align:start position:0% +right but if not then I need to go a try + + + align:start position:0% +right but if not then I need to go a try +the other combinations and I'm only + + align:start position:0% +the other combinations and I'm only + + + align:start position:0% +the other combinations and I'm only +going to Bob I'm only going to make that + + align:start position:0% +going to Bob I'm only going to make that + + + align:start position:0% +going to Bob I'm only going to make that +recursive call if the if obviously IJ e + + align:start position:0% +recursive call if the if obviously IJ e + + + align:start position:0% +recursive call if the if obviously IJ e +corresponding to this is is valid and + + align:start position:0% +corresponding to this is is valid and + + + align:start position:0% +corresponding to this is is valid and +that checks the constraints and the only + + align:start position:0% +that checks the constraints and the only + + + align:start position:0% +that checks the constraints and the only +other thing I have to worry about is it + + align:start position:0% +other thing I have to worry about is it + + + align:start position:0% +other thing I have to worry about is it +is is essentially something that says + + align:start position:0% +is is essentially something that says + + + align:start position:0% +is is essentially something that says +you know reset your grid location and + + align:start position:0% +you know reset your grid location and + + + align:start position:0% +you know reset your grid location and +make sure that that you're that you're + + align:start position:0% +make sure that that you're that you're + + + align:start position:0% +make sure that that you're that you're +setting it back to zero + + align:start position:0% +setting it back to zero + + + align:start position:0% +setting it back to zero +after after you're done right and so + + align:start position:0% +after after you're done right and so + + + align:start position:0% +after after you're done right and so +I've just made a choice here grid IJ + + align:start position:0% +I've just made a choice here grid IJ + + + align:start position:0% +I've just made a choice here grid IJ +equals Z if I look at this line of code + + align:start position:0% +equals Z if I look at this line of code + + + align:start position:0% +equals Z if I look at this line of code +here this is resetting the grid IJ + + align:start position:0% +here this is resetting the grid IJ + + + align:start position:0% +here this is resetting the grid IJ +equals Z and saying it's empty because + + align:start position:0% +equals Z and saying it's empty because + + + align:start position:0% +equals Z and saying it's empty because +if I've failed in all of these and I + + align:start position:0% +if I've failed in all of these and I + + + align:start position:0% +if I've failed in all of these and I +haven't returned true in all of these + + align:start position:0% +haven't returned true in all of these + + + align:start position:0% +haven't returned true in all of these +then obviously I want to change this and + + align:start position:0% +then obviously I want to change this and + + + align:start position:0% +then obviously I want to change this and +you could argue that the next time + + align:start position:0% +you could argue that the next time + + + align:start position:0% +you could argue that the next time +around if I and J are exactly the same + + align:start position:0% +around if I and J are exactly the same + + + align:start position:0% +around if I and J are exactly the same +because I and J are set up here then I'm + + align:start position:0% +because I and J are set up here then I'm + + + align:start position:0% +because I and J are set up here then I'm +going to override the e from a 1 to a 2 + + align:start position:0% +going to override the e from a 1 to a 2 + + + align:start position:0% +going to override the e from a 1 to a 2 +etc etc and so that is in fact correct + + align:start position:0% +etc etc and so that is in fact correct + + + align:start position:0% +etc etc and so that is in fact correct +but I do need I I do need to reset this + + align:start position:0% +but I do need I I do need to reset this + + + align:start position:0% +but I do need I I do need to reset this +outside of the loop if not inside of the + + align:start position:0% +outside of the loop if not inside of the + + + align:start position:0% +outside of the loop if not inside of the +loop so it's not like I can get away + + align:start position:0% +loop so it's not like I can get away + + + align:start position:0% +loop so it's not like I can get away +with this line of code I'm in general if + + align:start position:0% +with this line of code I'm in general if + + + align:start position:0% +with this line of code I'm in general if +you ever backtrack you have to go back + + align:start position:0% +you ever backtrack you have to go back + + + align:start position:0% +you ever backtrack you have to go back +and undo your decision and you have to + + align:start position:0% +and undo your decision and you have to + + + align:start position:0% +and undo your decision and you have to +erase the 3 and that's essentially what + + align:start position:0% +erase the 3 and that's essentially what + + + align:start position:0% +erase the 3 and that's essentially what +that grid IJ equaling 0 is doing right + + align:start position:0% +that grid IJ equaling 0 is doing right + + + align:start position:0% +that grid IJ equaling 0 is doing right +you just need to undo that decision and + + align:start position:0% +you just need to undo that decision and + + + align:start position:0% +you just need to undo that decision and +you can you can do this a few different + + align:start position:0% +you can you can do this a few different + + + align:start position:0% +you can you can do this a few different +ways but the biggest thing to remember + + align:start position:0% +ways but the biggest thing to remember + + + align:start position:0% +ways but the biggest thing to remember +when you do recursive search is to get + + align:start position:0% +when you do recursive search is to get + + + align:start position:0% +when you do recursive search is to get +your your the undoing if your decision + + align:start position:0% +your your the undoing if your decision + + + align:start position:0% +your your the undoing if your decision +which is what we call back + + align:start position:0% +which is what we call back + + + align:start position:0% +which is what we call back +to be correct and if you ever leave a + + align:start position:0% +to be correct and if you ever leave a + + + align:start position:0% +to be correct and if you ever leave a +mess then you'd have a problem that was + + align:start position:0% +mess then you'd have a problem that was + + + align:start position:0% +mess then you'd have a problem that was +that's also true in the case of the N + + align:start position:0% +that's also true in the case of the N + + + align:start position:0% +that's also true in the case of the N +Queens problem so I'm gonna go ahead and + + align:start position:0% +Queens problem so I'm gonna go ahead and + + + align:start position:0% +Queens problem so I'm gonna go ahead and +and this is just a print routine so this + + align:start position:0% +and this is just a print routine so this + + + align:start position:0% +and this is just a print routine so this +is not exactly the Sudoku that I have up + + align:start position:0% +is not exactly the Sudoku that I have up + + + align:start position:0% +is not exactly the Sudoku that I have up +up there the Sudoku puzzle that I have + + align:start position:0% +up there the Sudoku puzzle that I have + + + align:start position:0% +up there the Sudoku puzzle that I have +up there but it's kind of roughly + + align:start position:0% +up there but it's kind of roughly + + + align:start position:0% +up there but it's kind of roughly +similar in complexity and I can go ahead + + align:start position:0% +similar in complexity and I can go ahead + + + align:start position:0% +similar in complexity and I can go ahead +and run the pseudocode program and for + + align:start position:0% +and run the pseudocode program and for + + + align:start position:0% +and run the pseudocode program and for +each of those different Sudoku problems + + align:start position:0% +each of those different Sudoku problems + + + align:start position:0% +each of those different Sudoku problems +it's it's producing solve puzzles so + + align:start position:0% +it's it's producing solve puzzles so + + + align:start position:0% +it's it's producing solve puzzles so +this is a solved puzzle you can check + + align:start position:0% +this is a solved puzzle you can check + + + align:start position:0% +this is a solved puzzle you can check +this puzzle just real quick and you'll + + align:start position:0% +this puzzle just real quick and you'll + + + align:start position:0% +this puzzle just real quick and you'll +find that that all of the constraints + + align:start position:0% +find that that all of the constraints + + + align:start position:0% +find that that all of the constraints +are satisfied and then and I'm going to + + align:start position:0% +are satisfied and then and I'm going to + + + align:start position:0% +are satisfied and then and I'm going to +explain backtracks in a second so true + + align:start position:0% +explain backtracks in a second so true + + + align:start position:0% +explain backtracks in a second so true +says that there's a solution the number + + align:start position:0% +says that there's a solution the number + + + align:start position:0% +says that there's a solution the number +of backtracks was 579 for the second + + align:start position:0% +of backtracks was 579 for the second + + + align:start position:0% +of backtracks was 579 for the second +puzzle which was a little bit harder the + + align:start position:0% +puzzle which was a little bit harder the + + + align:start position:0% +puzzle which was a little bit harder the +number of backtracks was six three six + + align:start position:0% +number of backtracks was six three six + + + align:start position:0% +number of backtracks was six three six +three I'm sorry this is just scrolling + + align:start position:0% +three I'm sorry this is just scrolling + + + align:start position:0% +three I'm sorry this is just scrolling +and for the fourth one it was 335 + + align:start position:0% +and for the fourth one it was 335 + + + align:start position:0% +and for the fourth one it was 335 +thousand and I'm sorry for the third one + + align:start position:0% +thousand and I'm sorry for the third one + + + align:start position:0% +thousand and I'm sorry for the third one +and for the fourth one was 99 49 okay + + align:start position:0% +and for the fourth one was 99 49 okay + + + align:start position:0% +and for the fourth one was 99 49 okay +these last two puzzles hard and if there + + align:start position:0% +these last two puzzles hard and if there + + + align:start position:0% +these last two puzzles hard and if there +was a finished guy called or there is a + + align:start position:0% +was a finished guy called or there is a + + + align:start position:0% +was a finished guy called or there is a +finish guy called our toe in kala who + + align:start position:0% +finish guy called our toe in kala who + + + align:start position:0% +finish guy called our toe in kala who +designs puzzles and he claimed that this + + align:start position:0% +designs puzzles and he claimed that this + + + align:start position:0% +designs puzzles and he claimed that this +hard puzzle in 2006 was the hardest + + align:start position:0% +hard puzzle in 2006 was the hardest + + + align:start position:0% +hard puzzle in 2006 was the hardest +puzzle ever design in Sudoku and then in + + align:start position:0% +puzzle ever design in Sudoku and then in + + + align:start position:0% +puzzle ever design in Sudoku and then in +2010 he came up with this more difficult + + align:start position:0% +2010 he came up with this more difficult + + + align:start position:0% +2010 he came up with this more difficult +puzzle according to him that required a + + align:start position:0% +puzzle according to him that required a + + + align:start position:0% +puzzle according to him that required a +lot of look ahead from a standpoint of + + align:start position:0% +lot of look ahead from a standpoint of + + + align:start position:0% +lot of look ahead from a standpoint of +the human being like you know we went + + align:start position:0% +the human being like you know we went + + + align:start position:0% +the human being like you know we went +back to what I said you-you-you can't + + align:start position:0% +back to what I said you-you-you can't + + + align:start position:0% +back to what I said you-you-you can't +quite do this implication you have to + + align:start position:0% +quite do this implication you have to + + + align:start position:0% +quite do this implication you have to +kind of make a guess and then you have + + align:start position:0% +kind of make a guess and then you have + + + align:start position:0% +kind of make a guess and then you have +to go further and further down and that + + align:start position:0% +to go further and further down and that + + + align:start position:0% +to go further and further down and that +I think the claim was that the hard + + align:start position:0% +I think the claim was that the hard + + + align:start position:0% +I think the claim was that the hard +puzzle required like five levels of look + + align:start position:0% +puzzle required like five levels of look + + + align:start position:0% +puzzle required like five levels of look +ahead and then the difficult puzzle + + align:start position:0% +ahead and then the difficult puzzle + + + align:start position:0% +ahead and then the difficult puzzle +required six levels of look ahead and + + align:start position:0% +required six levels of look ahead and + + + align:start position:0% +required six levels of look ahead and +obviously I given that look ahead this + + align:start position:0% +obviously I given that look ahead this + + + align:start position:0% +obviously I given that look ahead this +puzzle has to have an initial + + align:start position:0% +puzzle has to have an initial + + + align:start position:0% +puzzle has to have an initial +configuration that solvable so it's not + + align:start position:0% +configuration that solvable so it's not + + + align:start position:0% +configuration that solvable so it's not +a trivial thing to create puzzles but + + align:start position:0% +a trivial thing to create puzzles but + + + align:start position:0% +a trivial thing to create puzzles but +now people are using computer programs + + align:start position:0% +now people are using computer programs + + + align:start position:0% +now people are using computer programs +and doing things like we are doing here + + align:start position:0% +and doing things like we are doing here + + + align:start position:0% +and doing things like we are doing here +too + + align:start position:0% +too + + + align:start position:0% +too +to find difficult puzzles and + + align:start position:0% +to find difficult puzzles and + + + align:start position:0% +to find difficult puzzles and +interestingly enough the 2006 puzzle at + + align:start position:0% +interestingly enough the 2006 puzzle at + + + align:start position:0% +interestingly enough the 2006 puzzle at +least for this naive computer program it + + align:start position:0% +least for this naive computer program it + + + align:start position:0% +least for this naive computer program it +takes three hundred and thirty-five + + align:start position:0% +takes three hundred and thirty-five + + + align:start position:0% +takes three hundred and thirty-five +thousand backtracks the one that that + + align:start position:0% +thousand backtracks the one that that + + + align:start position:0% +thousand backtracks the one that that +was supposedly made more difficult into + + align:start position:0% +was supposedly made more difficult into + + + align:start position:0% +was supposedly made more difficult into +2010 which which not only takes you know + + align:start position:0% +2010 which which not only takes you know + + + align:start position:0% +2010 which which not only takes you know +about ten thousand backtracks right so + + align:start position:0% +about ten thousand backtracks right so + + + align:start position:0% +about ten thousand backtracks right so +obviously there's a difference between + + align:start position:0% +obviously there's a difference between + + + align:start position:0% +obviously there's a difference between +the way this this program behaves and + + align:start position:0% +the way this this program behaves and + + + align:start position:0% +the way this this program behaves and +how you or I would behave or that you + + align:start position:0% +how you or I would behave or that you + + + align:start position:0% +how you or I would behave or that you +would behave if you try to solve this + + align:start position:0% +would behave if you try to solve this + + + align:start position:0% +would behave if you try to solve this +puzzle okay so let me just explain + + align:start position:0% +puzzle okay so let me just explain + + + align:start position:0% +puzzle okay so let me just explain +backtracks and I'll stop to see if + + align:start position:0% +backtracks and I'll stop to see if + + + align:start position:0% +backtracks and I'll stop to see if +there's any questions about the code so + + align:start position:0% +there's any questions about the code so + + + align:start position:0% +there's any questions about the code so +when you make recursive calls and you + + align:start position:0% +when you make recursive calls and you + + + align:start position:0% +when you make recursive calls and you +want to count the number of recursive + + align:start position:0% +want to count the number of recursive + + + align:start position:0% +want to count the number of recursive +procedure calls you want to do something + + align:start position:0% +procedure calls you want to do something + + + align:start position:0% +procedure calls you want to do something +inside each of the recursive procedures + + align:start position:0% +inside each of the recursive procedures + + + align:start position:0% +inside each of the recursive procedures +and you want to sort of cumulatively or + + align:start position:0% +and you want to sort of cumulatively or + + + align:start position:0% +and you want to sort of cumulatively or +collectively keep some information one + + align:start position:0% +collectively keep some information one + + + align:start position:0% +collectively keep some information one +way of certainly doing it is to pass + + align:start position:0% +way of certainly doing it is to pass + + + align:start position:0% +way of certainly doing it is to pass +arguments and then you have to return + + align:start position:0% +arguments and then you have to return + + + align:start position:0% +arguments and then you have to return +the argument because when you pass an + + align:start position:0% +the argument because when you pass an + + + align:start position:0% +the argument because when you pass an +argument and you you you modify it it's + + align:start position:0% +argument and you you you modify it it's + + + align:start position:0% +argument and you you you modify it it's +it's not like that is going to be that + + align:start position:0% +it's not like that is going to be that + + + align:start position:0% +it's not like that is going to be that +modification if it's not if it's just an + + align:start position:0% +modification if it's not if it's just an + + + align:start position:0% +modification if it's not if it's just an +integer if it's not a mutable if it's + + align:start position:0% +integer if it's not a mutable if it's + + + align:start position:0% +integer if it's not a mutable if it's +not a mutable variable it's not going to + + align:start position:0% +not a mutable variable it's not going to + + + align:start position:0% +not a mutable variable it's not going to +be seen by the caller procedure and so + + align:start position:0% +be seen by the caller procedure and so + + + align:start position:0% +be seen by the caller procedure and so +when you do recursion and you want to do + + align:start position:0% +when you do recursion and you want to do + + + align:start position:0% +when you do recursion and you want to do +some counting the notion of global + + align:start position:0% +some counting the notion of global + + + align:start position:0% +some counting the notion of global +variables is a convenient construct to + + align:start position:0% +variables is a convenient construct to + + + align:start position:0% +variables is a convenient construct to +have okay and global variables + + align:start position:0% +have okay and global variables + + + align:start position:0% +have okay and global variables +essentially say that there's exactly one + + align:start position:0% +essentially say that there's exactly one + + + align:start position:0% +essentially say that there's exactly one +memory location associated with this + + align:start position:0% +memory location associated with this + + + align:start position:0% +memory location associated with this +variable and we're going to go ahead and + + align:start position:0% +variable and we're going to go ahead and + + + align:start position:0% +variable and we're going to go ahead and +anytime we are mutating this variable + + align:start position:0% +anytime we are mutating this variable + + + align:start position:0% +anytime we are mutating this variable +and you're modifying it you're going to + + align:start position:0% +and you're modifying it you're going to + + + align:start position:0% +and you're modifying it you're going to +see the effect of that in that memory + + align:start position:0% +see the effect of that in that memory + + + align:start position:0% +see the effect of that in that memory +location okay so so what you have here + + align:start position:0% +location okay so so what you have here + + + align:start position:0% +location okay so so what you have here +up here is I set back crack's to be zero + + align:start position:0% +up here is I set back crack's to be zero + + + align:start position:0% +up here is I set back crack's to be zero +okay and that's my global variable the + + align:start position:0% +okay and that's my global variable the + + + align:start position:0% +okay and that's my global variable the +fact that I put back crack's equals zero + + align:start position:0% +fact that I put back crack's equals zero + + + align:start position:0% +fact that I put back crack's equals zero +here doesn't make this a global variable + + align:start position:0% +here doesn't make this a global variable + + + align:start position:0% +here doesn't make this a global variable +just yet um the fact that I have global + + align:start position:0% +just yet um the fact that I have global + + + align:start position:0% +just yet um the fact that I have global +backtracks inside of solve Sudoku now + + align:start position:0% +backtracks inside of solve Sudoku now + + + align:start position:0% +backtracks inside of solve Sudoku now +says that there's a single copy of + + align:start position:0% +says that there's a single copy of + + + align:start position:0% +says that there's a single copy of +backtracks and it doesn't matter whether + + align:start position:0% +backtracks and it doesn't matter whether + + + align:start position:0% +backtracks and it doesn't matter whether +I'm you know at the top level of + + align:start position:0% +I'm you know at the top level of + + + align:start position:0% +I'm you know at the top level of +recursion or the bottom level of + + align:start position:0% +recursion or the bottom level of + + + align:start position:0% +recursion or the bottom level of +recursion + + align:start position:0% +recursion + + + align:start position:0% +recursion +it's just that memory location + + align:start position:0% +it's just that memory location + + + align:start position:0% +it's just that memory location +corresponding to the backtracks the name + + align:start position:0% +corresponding to the backtracks the name + + + align:start position:0% +corresponding to the backtracks the name +backtracks that is getting incremented + + align:start position:0% +backtracks that is getting incremented + + + align:start position:0% +backtracks that is getting incremented +and this could be you know + + align:start position:0% +and this could be you know + + + align:start position:0% +and this could be you know +ten levels deep it could be 40 levels + + align:start position:0% +ten levels deep it could be 40 levels + + + align:start position:0% +ten levels deep it could be 40 levels +deep given that I've called things you + + align:start position:0% +deep given that I've called things you + + + align:start position:0% +deep given that I've called things you +know 40 levels in but it's just the one + + align:start position:0% +know 40 levels in but it's just the one + + + align:start position:0% +know 40 levels in but it's just the one +backtracks okay so as you can see what + + align:start position:0% +backtracks okay so as you can see what + + + align:start position:0% +backtracks okay so as you can see what +backtracks does is anytime you have a + + align:start position:0% +backtracks does is anytime you have a + + + align:start position:0% +backtracks does is anytime you have a +valid location and you've gone ahead and + + align:start position:0% +valid location and you've gone ahead and + + + align:start position:0% +valid location and you've gone ahead and +and essentially you don't you failed the + + align:start position:0% +and essentially you don't you failed the + + + align:start position:0% +and essentially you don't you failed the +reason it's out here is salsa Doku did + + align:start position:0% +reason it's out here is salsa Doku did + + + align:start position:0% +reason it's out here is salsa Doku did +not return true when salsa Roku actually + + align:start position:0% +not return true when salsa Roku actually + + + align:start position:0% +not return true when salsa Roku actually +returns false is that's when you you you + + align:start position:0% +returns false is that's when you you you + + + align:start position:0% +returns false is that's when you you you +you come out and you increment + + align:start position:0% +you come out and you increment + + + align:start position:0% +you come out and you increment +backtracks okay so so it meant that you + + align:start position:0% +backtracks okay so so it meant that you + + + align:start position:0% +backtracks okay so so it meant that you +you had to do some undoing you know when + + align:start position:0% +you had to do some undoing you know when + + + align:start position:0% +you had to do some undoing you know when +you set grid IJ to be 0 that's when + + align:start position:0% +you set grid IJ to be 0 that's when + + + align:start position:0% +you set grid IJ to be 0 that's when +you're undoing your your guess right so + + align:start position:0% +you're undoing your your guess right so + + + align:start position:0% +you're undoing your your guess right so +back tracks you know makes sense from a + + align:start position:0% +back tracks you know makes sense from a + + + align:start position:0% +back tracks you know makes sense from a +standpoint of I need to backtrack and go + + align:start position:0% +standpoint of I need to backtrack and go + + + align:start position:0% +standpoint of I need to backtrack and go +in a different fork in the road okay and + + align:start position:0% +in a different fork in the road okay and + + + align:start position:0% +in a different fork in the road okay and +so that's why I have back tracks plus + + align:start position:0% +so that's why I have back tracks plus + + + align:start position:0% +so that's why I have back tracks plus +equals one right when I'm undoing you + + align:start position:0% +equals one right when I'm undoing you + + + align:start position:0% +equals one right when I'm undoing you +know my decision that I made right so + + align:start position:0% +know my decision that I made right so + + + align:start position:0% +know my decision that I made right so +this kind of gives you a sense for how + + align:start position:0% +this kind of gives you a sense for how + + + align:start position:0% +this kind of gives you a sense for how +many wrong guesses that this program did + + align:start position:0% +many wrong guesses that this program did + + + align:start position:0% +many wrong guesses that this program did +and as you can imagine then more the + + align:start position:0% +and as you can imagine then more the + + + align:start position:0% +and as you can imagine then more the +number of wrong guesses the more the + + align:start position:0% +number of wrong guesses the more the + + + align:start position:0% +number of wrong guesses the more the +computation and the longer it takes so + + align:start position:0% +computation and the longer it takes so + + + align:start position:0% +computation and the longer it takes so +it is definitely a proxy for performance + + align:start position:0% +it is definitely a proxy for performance + + + align:start position:0% +it is definitely a proxy for performance +but it's a it's a platform independent + + align:start position:0% +but it's a it's a platform independent + + + align:start position:0% +but it's a it's a platform independent +proxy that's more algorithm related as + + align:start position:0% +proxy that's more algorithm related as + + + align:start position:0% +proxy that's more algorithm related as +opposed to the speed of the computer + + align:start position:0% +opposed to the speed of the computer + + + align:start position:0% +opposed to the speed of the computer +because if this computer were twice as + + align:start position:0% +because if this computer were twice as + + + align:start position:0% +because if this computer were twice as +fast I mean I just see things running + + align:start position:0% +fast I mean I just see things running + + + align:start position:0% +fast I mean I just see things running +faster even though the algorithm isn't + + align:start position:0% +faster even though the algorithm isn't + + + align:start position:0% +faster even though the algorithm isn't +any better right that makes sense right + + align:start position:0% +any better right that makes sense right + + + align:start position:0% +any better right that makes sense right +so it's a very simple use of global but + + align:start position:0% +so it's a very simple use of global but + + + align:start position:0% +so it's a very simple use of global but +you don't want to use global variables + + align:start position:0% +you don't want to use global variables + + + align:start position:0% +you don't want to use global variables +except in certain constraint settings + + align:start position:0% +except in certain constraint settings + + + align:start position:0% +except in certain constraint settings +this is a fine use of global variables + + align:start position:0% +this is a fine use of global variables + + + align:start position:0% +this is a fine use of global variables +right cool good so any questions about + + align:start position:0% +right cool good so any questions about + + + align:start position:0% +right cool good so any questions about +this code so what I've done here is I + + align:start position:0% +this code so what I've done here is I + + + align:start position:0% +this code so what I've done here is I +just have the naive code and I happen to + + align:start position:0% +just have the naive code and I happen to + + + align:start position:0% +just have the naive code and I happen to +have different numbers of backtracks + + align:start position:0% +have different numbers of backtracks + + + align:start position:0% +have different numbers of backtracks +because I have different inputs unlike + + align:start position:0% +because I have different inputs unlike + + + align:start position:0% +because I have different inputs unlike +the n-queens problem which is kind of + + align:start position:0% +the n-queens problem which is kind of + + + align:start position:0% +the n-queens problem which is kind of +boring in some sense because once you've + + align:start position:0% +boring in some sense because once you've + + + align:start position:0% +boring in some sense because once you've +solved it there's nothing left in the + + align:start position:0% +solved it there's nothing left in the + + + align:start position:0% +solved it there's nothing left in the +case of Sudoku I could change my input + + align:start position:0% +case of Sudoku I could change my input + + + align:start position:0% +case of Sudoku I could change my input +my starting point and give you a + + align:start position:0% +my starting point and give you a + + + align:start position:0% +my starting point and give you a +different different problems right and + + align:start position:0% +different different problems right and + + + align:start position:0% +different different problems right and +so so the reason we had many different + + align:start position:0% +so so the reason we had many different + + + align:start position:0% +so so the reason we had many different +kinds of backtracks + + align:start position:0% +kinds of backtracks + + + align:start position:0% +kinds of backtracks +was was simply because numbers of + + align:start position:0% +was was simply because numbers of + + + align:start position:0% +was was simply because numbers of +backtracks was because we had four + + align:start position:0% +backtracks was because we had four + + + align:start position:0% +backtracks was because we had four +different inputs to the Sudoku puzzle + + align:start position:0% +different inputs to the Sudoku puzzle + + + align:start position:0% +different inputs to the Sudoku puzzle +all right + + align:start position:0% +all right + + + align:start position:0% +all right +so are we good here people understand + + align:start position:0% +so are we good here people understand + + + align:start position:0% +so are we good here people understand +this code you're gonna have to modify it + + align:start position:0% +this code you're gonna have to modify it + + + align:start position:0% +this code you're gonna have to modify it +right now not necessarily this code + + align:start position:0% +right now not necessarily this code + + + align:start position:0% +right now not necessarily this code +depending on the exercise you do but + + align:start position:0% +depending on the exercise you do but + + + align:start position:0% +depending on the exercise you do but +this is certainly something that + + align:start position:0% +this is certainly something that + + + align:start position:0% +this is certainly something that +hopefully you feel comfortable with + + align:start position:0% +hopefully you feel comfortable with + + + align:start position:0% +hopefully you feel comfortable with +potentially modifying all right so what + + align:start position:0% +potentially modifying all right so what + + + align:start position:0% +potentially modifying all right so what +I'm going to do now is at first I'm + + align:start position:0% +I'm going to do now is at first I'm + + + align:start position:0% +I'm going to do now is at first I'm +going to go ahead and show you some code + + align:start position:0% +going to go ahead and show you some code + + + align:start position:0% +going to go ahead and show you some code +that corresponds to something that I is + + align:start position:0% +that corresponds to something that I is + + + align:start position:0% +that corresponds to something that I is +the original code except that I'm gonna + + align:start position:0% +the original code except that I'm gonna + + + align:start position:0% +the original code except that I'm gonna +add some smarts to it all right what I'm + + align:start position:0% +add some smarts to it all right what I'm + + + align:start position:0% +add some smarts to it all right what I'm +going to do is at any given point of + + align:start position:0% +going to do is at any given point of + + + align:start position:0% +going to do is at any given point of +time I'm gonna try to do some + + align:start position:0% +time I'm gonna try to do some + + + align:start position:0% +time I'm gonna try to do some +implications without actually doing any + + align:start position:0% +implications without actually doing any + + + align:start position:0% +implications without actually doing any +guessing right so the way I'm going to + + align:start position:0% +guessing right so the way I'm going to + + + align:start position:0% +guessing right so the way I'm going to +integrate the human approach into this + + align:start position:0% +integrate the human approach into this + + + align:start position:0% +integrate the human approach into this +exhaustive search approach a top level + + align:start position:0% +exhaustive search approach a top level + + + align:start position:0% +exhaustive search approach a top level +is I'm gonna take my configuration and + + align:start position:0% +is I'm gonna take my configuration and + + + align:start position:0% +is I'm gonna take my configuration and +before I do an arbitrary guess before I + + align:start position:0% +before I do an arbitrary guess before I + + + align:start position:0% +before I do an arbitrary guess before I +call find next cell or maybe I have a + + align:start position:0% +call find next cell or maybe I have a + + + align:start position:0% +call find next cell or maybe I have a +particular location here that I'm + + align:start position:0% +particular location here that I'm + + + align:start position:0% +particular location here that I'm +eventually going to guess so I do know + + align:start position:0% +eventually going to guess so I do know + + + align:start position:0% +eventually going to guess so I do know +that but before that I'm going to try + + align:start position:0% +that but before that I'm going to try + + + align:start position:0% +that but before that I'm going to try +and see whether the current grid values + + align:start position:0% +and see whether the current grid values + + + align:start position:0% +and see whether the current grid values +imply anything or not by using the rules + + align:start position:0% +imply anything or not by using the rules + + + align:start position:0% +imply anything or not by using the rules +in exactly the same way or roughly I + + align:start position:0% +in exactly the same way or roughly I + + + align:start position:0% +in exactly the same way or roughly I +should say the same way that we did + + align:start position:0% +should say the same way that we did + + + align:start position:0% +should say the same way that we did +right when we began the lecture all + + align:start position:0% +right when we began the lecture all + + + align:start position:0% +right when we began the lecture all +right so if we're going to try and use + + align:start position:0% +right so if we're going to try and use + + + align:start position:0% +right so if we're going to try and use +some implications and maybe imply the + + align:start position:0% +some implications and maybe imply the + + + align:start position:0% +some implications and maybe imply the +eight or imply something different + + align:start position:0% +eight or imply something different + + + align:start position:0% +eight or imply something different +associated with some other location + + align:start position:0% +associated with some other location + + + align:start position:0% +associated with some other location +right so this is not a backtrack right + + align:start position:0% +right so this is not a backtrack right + + + align:start position:0% +right so this is not a backtrack right +in the sense that this is going to be I + + align:start position:0% +in the sense that this is going to be I + + + align:start position:0% +in the sense that this is going to be I +can take this to the bank assuming I + + align:start position:0% +can take this to the bank assuming I + + + align:start position:0% +can take this to the bank assuming I +haven't done any guessing up until this + + align:start position:0% +haven't done any guessing up until this + + + align:start position:0% +haven't done any guessing up until this +point and assuming that the initial + + align:start position:0% +point and assuming that the initial + + + align:start position:0% +point and assuming that the initial +configuration that was given to me + + align:start position:0% +configuration that was given to me + + + align:start position:0% +configuration that was given to me +corresponds to a valid solution right + + align:start position:0% +corresponds to a valid solution right + + + align:start position:0% +corresponds to a valid solution right +but I'm actually going to do this at + + align:start position:0% +but I'm actually going to do this at + + + align:start position:0% +but I'm actually going to do this at +different points in the search so it + + align:start position:0% +different points in the search so it + + + align:start position:0% +different points in the search so it +might be that I'm just gonna arbitrarily + + align:start position:0% +might be that I'm just gonna arbitrarily + + + align:start position:0% +might be that I'm just gonna arbitrarily +choose a two here okay and and so I go + + align:start position:0% +choose a two here okay and and so I go + + + align:start position:0% +choose a two here okay and and so I go +through and I and and and I'm gonna uh + + align:start position:0% +through and I and and and I'm gonna uh + + + align:start position:0% +through and I and and and I'm gonna uh +take this in for argument's sake and I'm + + align:start position:0% +take this in for argument's sake and I'm + + + align:start position:0% +take this in for argument's sake and I'm +gonna put up two down and then I have + + align:start position:0% +gonna put up two down and then I have + + + align:start position:0% +gonna put up two down and then I have +not the initial puzzle that was given to + + align:start position:0% +not the initial puzzle that was given to + + + align:start position:0% +not the initial puzzle that was given to +me but something that I've kind of + + align:start position:0% +me but something that I've kind of + + + align:start position:0% +me but something that I've kind of +hacked in the center of stuck a two in + + align:start position:0% +hacked in the center of stuck a two in + + + align:start position:0% +hacked in the center of stuck a two in +there and that may not correspond to the + + align:start position:0% +there and that may not correspond to the + + + align:start position:0% +there and that may not correspond to the +solution because I just sort of put the + + align:start position:0% +solution because I just sort of put the + + + align:start position:0% +solution because I just sort of put the +two down there but now given the two I'm + + align:start position:0% +two down there but now given the two I'm + + + align:start position:0% +two down there but now given the two I'm +try and do some implications okay and + + align:start position:0% +try and do some implications okay and + + + align:start position:0% +try and do some implications okay and +I'm gonna try and see whether there + + align:start position:0% +I'm gonna try and see whether there + + + align:start position:0% +I'm gonna try and see whether there +there's things that are valid or not the + + align:start position:0% +there's things that are valid or not the + + + align:start position:0% +there's things that are valid or not the +important thing is that because I put a + + align:start position:0% +important thing is that because I put a + + + align:start position:0% +important thing is that because I put a +two down in an arbitrary way without + + align:start position:0% +two down in an arbitrary way without + + + align:start position:0% +two down in an arbitrary way without +using implications the two could have + + align:start position:0% +using implications the two could have + + + align:start position:0% +using implications the two could have +been incorrect I mean that's exactly why + + align:start position:0% +been incorrect I mean that's exactly why + + + align:start position:0% +been incorrect I mean that's exactly why +we have all of these back tracks correct + + align:start position:0% +we have all of these back tracks correct + + + align:start position:0% +we have all of these back tracks correct +because I've put down incorrect guesses + + align:start position:0% +because I've put down incorrect guesses + + + align:start position:0% +because I've put down incorrect guesses +and then I've had to backtrack so once I + + align:start position:0% +and then I've had to backtrack so once I + + + align:start position:0% +and then I've had to backtrack so once I +put a two down and then I fill in a + + align:start position:0% +put a two down and then I fill in a + + + align:start position:0% +put a two down and then I fill in a +bunch of things with implications you + + align:start position:0% +bunch of things with implications you + + + align:start position:0% +bunch of things with implications you +know I may even put an ad up there I may + + align:start position:0% +know I may even put an ad up there I may + + + align:start position:0% +know I may even put an ad up there I may +put a six out here etc etc and I go deep + + align:start position:0% +put a six out here etc etc and I go deep + + + align:start position:0% +put a six out here etc etc and I go deep +in and then I realized oh you know that + + align:start position:0% +in and then I realized oh you know that + + + align:start position:0% +in and then I realized oh you know that +too was a mistake okay the two should + + align:start position:0% +too was a mistake okay the two should + + + align:start position:0% +too was a mistake okay the two should +really should have been in there okay + + align:start position:0% +really should have been in there okay + + + align:start position:0% +really should have been in there okay +now I have to clean up everything I have + + align:start position:0% +now I have to clean up everything I have + + + align:start position:0% +now I have to clean up everything I have +to clean up all of the guesses that came + + align:start position:0% +to clean up all of the guesses that came + + + align:start position:0% +to clean up all of the guesses that came +after - and all of the implications that + + align:start position:0% +after - and all of the implications that + + + align:start position:0% +after - and all of the implications that +came after - all right that's the + + align:start position:0% +came after - all right that's the + + + align:start position:0% +came after - all right that's the +biggest thing that I wanted you to take + + align:start position:0% +biggest thing that I wanted you to take + + + align:start position:0% +biggest thing that I wanted you to take +away from this integration of + + align:start position:0% +away from this integration of + + + align:start position:0% +away from this integration of +implications with the exhaustive search + + align:start position:0% +implications with the exhaustive search + + + align:start position:0% +implications with the exhaustive search +it's clean up your mess clean up your + + align:start position:0% +it's clean up your mess clean up your + + + align:start position:0% +it's clean up your mess clean up your +bad guesses your the fact that you say + + align:start position:0% +bad guesses your the fact that you say + + + align:start position:0% +bad guesses your the fact that you say +oh but the implication was was something + + align:start position:0% +oh but the implication was was something + + + align:start position:0% +oh but the implication was was something +that was deterministic it was exactly + + align:start position:0% +that was deterministic it was exactly + + + align:start position:0% +that was deterministic it was exactly +following these rules + + align:start position:0% +following these rules + + + align:start position:0% +following these rules +nananana yeah it was deterministic all + + align:start position:0% +nananana yeah it was deterministic all + + + align:start position:0% +nananana yeah it was deterministic all +of that is true but you made a wrong + + align:start position:0% +of that is true but you made a wrong + + + align:start position:0% +of that is true but you made a wrong +guess and therefore everything that you + + align:start position:0% +guess and therefore everything that you + + + align:start position:0% +guess and therefore everything that you +did from then on out is is in question + + align:start position:0% +did from then on out is is in question + + + align:start position:0% +did from then on out is is in question +and if you in fact find a contradiction + + align:start position:0% +and if you in fact find a contradiction + + + align:start position:0% +and if you in fact find a contradiction +you got to go all the way back and clean + + align:start position:0% +you got to go all the way back and clean + + + align:start position:0% +you got to go all the way back and clean +up everything and then go back and erase + + align:start position:0% +up everything and then go back and erase + + + align:start position:0% +up everything and then go back and erase +everything that you had and then go take + + align:start position:0% +everything that you had and then go take + + + align:start position:0% +everything that you had and then go take +this too and maybe turn it into a three + + align:start position:0% +this too and maybe turn it into a three + + + align:start position:0% +this too and maybe turn it into a three +or what have you + + align:start position:0% +or what have you + + + align:start position:0% +or what have you +all right so um before I show you the + + align:start position:0% +all right so um before I show you the + + + align:start position:0% +all right so um before I show you the +code that does the implications and you + + align:start position:0% +code that does the implications and you + + + align:start position:0% +code that does the implications and you +can kind of imagine that there's many + + align:start position:0% +can kind of imagine that there's many + + + align:start position:0% +can kind of imagine that there's many +ways of you could do implications we did + + align:start position:0% +ways of you could do implications we did + + + align:start position:0% +ways of you could do implications we did +that manually I want to show you this + + align:start position:0% +that manually I want to show you this + + + align:start position:0% +that manually I want to show you this +part looks exactly the same as before + + align:start position:0% +part looks exactly the same as before + + + align:start position:0% +part looks exactly the same as before +no change fine next cell - grid is + + align:start position:0% +no change fine next cell - grid is + + + align:start position:0% +no change fine next cell - grid is +exactly the same it's valid is exactly + + align:start position:0% +exactly the same it's valid is exactly + + + align:start position:0% +exactly the same it's valid is exactly +the same right um there's a large make + + align:start position:0% +the same right um there's a large make + + + align:start position:0% +the same right um there's a large make +implications procedure and an undo + + align:start position:0% +implications procedure and an undo + + + align:start position:0% +implications procedure and an undo +implications that I'll get to in a + + align:start position:0% +implications that I'll get to in a + + + align:start position:0% +implications that I'll get to in a +second but this part here looks almost + + align:start position:0% +second but this part here looks almost + + + align:start position:0% +second but this part here looks almost +exactly the same except that I've + + align:start position:0% +exactly the same except that I've + + + align:start position:0% +exactly the same except that I've +replaced grid I J equals E with make + + align:start position:0% +replaced grid I J equals E with make + + + align:start position:0% +replaced grid I J equals E with make +implications okay + + align:start position:0% +implications okay + + + align:start position:0% +implications okay +and this is something that not only is + + align:start position:0% +and this is something that not only is + + + align:start position:0% +and this is something that not only is +what is what make implications is going + + align:start position:0% +what is what make implications is going + + + align:start position:0% +what is what make implications is going +to do is it's going to set whatever I + + align:start position:0% +to do is it's going to set whatever I + + + align:start position:0% +to do is it's going to set whatever I +had up here it's going to set to up here + + align:start position:0% +had up here it's going to set to up here + + + align:start position:0% +had up here it's going to set to up here +and on top of that it's going to go use + + align:start position:0% +and on top of that it's going to go use + + + align:start position:0% +and on top of that it's going to go use +these things to go fill in a bunch of + + align:start position:0% +these things to go fill in a bunch of + + + align:start position:0% +these things to go fill in a bunch of +different values in here right so it's + + align:start position:0% +different values in here right so it's + + + align:start position:0% +different values in here right so it's +one extra step this is the integration + + align:start position:0% +one extra step this is the integration + + + align:start position:0% +one extra step this is the integration +that I talked about so the idea is that + + align:start position:0% +that I talked about so the idea is that + + + align:start position:0% +that I talked about so the idea is that +now you could do this for the original + + align:start position:0% +now you could do this for the original + + + align:start position:0% +now you could do this for the original +the original as well but the point is + + align:start position:0% +the original as well but the point is + + + align:start position:0% +the original as well but the point is +once you've made a guess you always want + + align:start position:0% +once you've made a guess you always want + + + align:start position:0% +once you've made a guess you always want +to check to see whether that guess does + + align:start position:0% +to check to see whether that guess does + + + align:start position:0% +to check to see whether that guess does +certain implications or not right I mean + + align:start position:0% +certain implications or not right I mean + + + align:start position:0% +certain implications or not right I mean +that's the whole purpose of this + + align:start position:0% +that's the whole purpose of this + + + align:start position:0% +that's the whole purpose of this +exercise even humans do this in the very + + align:start position:0% +exercise even humans do this in the very + + + align:start position:0% +exercise even humans do this in the very +difficult puzzles they make a guess and + + align:start position:0% +difficult puzzles they make a guess and + + + align:start position:0% +difficult puzzles they make a guess and +then they see whether there's some + + align:start position:0% +then they see whether there's some + + + align:start position:0% +then they see whether there's some +implication or not and and maybe there's + + align:start position:0% +implication or not and and maybe there's + + + align:start position:0% +implication or not and and maybe there's +a contradiction and they have to go back + + align:start position:0% +a contradiction and they have to go back + + + align:start position:0% +a contradiction and they have to go back +and and undo all of that damage they + + align:start position:0% +and and undo all of that damage they + + + align:start position:0% +and and undo all of that damage they +caused and change the guess okay but in + + align:start position:0% +caused and change the guess okay but in + + + align:start position:0% +caused and change the guess okay but in +general when you have a configuration + + align:start position:0% +general when you have a configuration + + + align:start position:0% +general when you have a configuration +and you add to it it's possible + + align:start position:0% +and you add to it it's possible + + + align:start position:0% +and you add to it it's possible +certainly that there will be other + + align:start position:0% +certainly that there will be other + + + align:start position:0% +certainly that there will be other +things that are employed by the the one + + align:start position:0% +things that are employed by the the one + + + align:start position:0% +things that are employed by the the one +change that you made to it all right so + + align:start position:0% +change that you made to it all right so + + + align:start position:0% +change that you made to it all right so +grid IJ equals E in the original code + + align:start position:0% +grid IJ equals E in the original code + + + align:start position:0% +grid IJ equals E in the original code +got replaced with this procedure that + + align:start position:0% +got replaced with this procedure that + + + align:start position:0% +got replaced with this procedure that +we'll talk about which I don't want to + + align:start position:0% +we'll talk about which I don't want to + + + align:start position:0% +we'll talk about which I don't want to +spend a whole lot of time on but it's + + align:start position:0% +spend a whole lot of time on but it's + + + align:start position:0% +spend a whole lot of time on but it's +it's essentially something in terms of + + align:start position:0% +it's essentially something in terms of + + + align:start position:0% +it's essentially something in terms of +details but it's essentially something + + align:start position:0% +details but it's essentially something + + + align:start position:0% +details but it's essentially something +that puts in different values in the + + align:start position:0% +that puts in different values in the + + + align:start position:0% +that puts in different values in the +different locations and grid IJ equals + + align:start position:0% +different locations and grid IJ equals + + + align:start position:0% +different locations and grid IJ equals +zero is replaced by undoing plication + + align:start position:0% +zero is replaced by undoing plication + + + align:start position:0% +zero is replaced by undoing plication +which is cleaning up all of the + + align:start position:0% +which is cleaning up all of the + + + align:start position:0% +which is cleaning up all of the +incorrect guesses and incorrect + + align:start position:0% +incorrect guesses and incorrect + + + align:start position:0% +incorrect guesses and incorrect +implications and the reason the + + align:start position:0% +implications and the reason the + + + align:start position:0% +implications and the reason the +implications are incorrect because it + + align:start position:0% +implications are incorrect because it + + + align:start position:0% +implications are incorrect because it +came from an incorrect guess okay and so + + align:start position:0% +came from an incorrect guess okay and so + + + align:start position:0% +came from an incorrect guess okay and so +so that's it undue implications is + + align:start position:0% +so that's it undue implications is + + + align:start position:0% +so that's it undue implications is +trivial it just sets all of the + + align:start position:0% +trivial it just sets all of the + + + align:start position:0% +trivial it just sets all of the +implications and I'll tell you what the + + align:start position:0% +implications and I'll tell you what the + + + align:start position:0% +implications and I'll tell you what the +data structure is in a second but think + + align:start position:0% +data structure is in a second but think + + + align:start position:0% +data structure is in a second but think +of it as as making everything zero going + + align:start position:0% +of it as as making everything zero going + + + align:start position:0% +of it as as making everything zero going +back to a clean slate right I mean clean + + align:start position:0% +back to a clean slate right I mean clean + + + align:start position:0% +back to a clean slate right I mean clean +slate in the sense that Minette + + align:start position:0% +slate in the sense that Minette + + + align:start position:0% +slate in the sense that Minette +implications and guesses are cleaned up + + align:start position:0% +implications and guesses are cleaned up + + + align:start position:0% +implications and guesses are cleaned up +all right so that's all there is over + + align:start position:0% +all right so that's all there is over + + + align:start position:0% +all right so that's all there is over +here make implications is you can do + + align:start position:0% +here make implications is you can do + + + align:start position:0% +here make implications is you can do +anything you want you can do you know + + align:start position:0% +anything you want you can do you know + + + align:start position:0% +anything you want you can do you know +vertical scans you can do horizontal + + align:start position:0% +vertical scans you can do horizontal + + + align:start position:0% +vertical scans you can do horizontal +scans you can there's if you go look at + + align:start position:0% +scans you can there's if you go look at + + + align:start position:0% +scans you can there's if you go look at +the pseudocode literature and you look + + align:start position:0% +the pseudocode literature and you look + + + align:start position:0% +the pseudocode literature and you look +in ways of playing Sudoku this books + + align:start position:0% +in ways of playing Sudoku this books + + + align:start position:0% +in ways of playing Sudoku this books +written on how you can become a better + + align:start position:0% +written on how you can become a better + + + align:start position:0% +written on how you can become a better +pseudo ku puzzle solver and there's it + + align:start position:0% +pseudo ku puzzle solver and there's it + + + align:start position:0% +pseudo ku puzzle solver and there's it +you could take that and you could code + + align:start position:0% +you could take that and you could code + + + align:start position:0% +you could take that and you could code +that in and you could replace make + + align:start position:0% +that in and you could replace make + + + align:start position:0% +that in and you could replace make +implications with those fancy techniques + + align:start position:0% +implications with those fancy techniques + + + align:start position:0% +implications with those fancy techniques +that are up there right but we've + + align:start position:0% +that are up there right but we've + + + align:start position:0% +that are up there right but we've +established I'm lazy and so I only write + + align:start position:0% +established I'm lazy and so I only write + + + align:start position:0% +established I'm lazy and so I only write +I only write a certain amount of code + + align:start position:0% +I only write a certain amount of code + + + align:start position:0% +I only write a certain amount of code +and then I get tired and so I wrote + + align:start position:0% +and then I get tired and so I wrote + + + align:start position:0% +and then I get tired and so I wrote +about 20 lines of code corresponding to + + align:start position:0% +about 20 lines of code corresponding to + + + align:start position:0% +about 20 lines of code corresponding to +a fairly straightforward implication + + align:start position:0% +a fairly straightforward implication + + + align:start position:0% +a fairly straightforward implication +just to give you a sense of of how this + + align:start position:0% +just to give you a sense of of how this + + + align:start position:0% +just to give you a sense of of how this +would work but the most important thing + + align:start position:0% +would work but the most important thing + + + align:start position:0% +would work but the most important thing +in here is not the details of making + + align:start position:0% +in here is not the details of making + + + align:start position:0% +in here is not the details of making +plication and I'll give you some sense + + align:start position:0% +plication and I'll give you some sense + + + align:start position:0% +plication and I'll give you some sense +of that before we're done but it's + + align:start position:0% +of that before we're done but it's + + + align:start position:0% +of that before we're done but it's +really this structure that is that that + + align:start position:0% +really this structure that is that that + + + align:start position:0% +really this structure that is that that +is the most important the fact that I've + + align:start position:0% +is the most important the fact that I've + + + align:start position:0% +is the most important the fact that I've +done make lubrications here and undo + + align:start position:0% +done make lubrications here and undo + + + align:start position:0% +done make lubrications here and undo +implications here it's the correctness a + + align:start position:0% +implications here it's the correctness a + + + align:start position:0% +implications here it's the correctness a +requirement that is important to + + align:start position:0% +requirement that is important to + + + align:start position:0% +requirement that is important to +exhaustive search okay so if I do this + + align:start position:0% +exhaustive search okay so if I do this + + + align:start position:0% +exhaustive search okay so if I do this +and and I do kind of the implications + + align:start position:0% +and and I do kind of the implications + + + align:start position:0% +and and I do kind of the implications +that we had right at the beginning of + + align:start position:0% +that we had right at the beginning of + + + align:start position:0% +that we had right at the beginning of +lecture and I go ahead and run it just + + align:start position:0% +lecture and I go ahead and run it just + + + align:start position:0% +lecture and I go ahead and run it just +take a look I won't write this out but + + align:start position:0% +take a look I won't write this out but + + + align:start position:0% +take a look I won't write this out but +remember what the back tracks are for + + align:start position:0% +remember what the back tracks are for + + + align:start position:0% +remember what the back tracks are for +these things roughly speaking for the + + align:start position:0% +these things roughly speaking for the + + + align:start position:0% +these things roughly speaking for the +original Sudoku I'm sorry + + align:start position:0% +original Sudoku I'm sorry + + + align:start position:0% +original Sudoku I'm sorry +I need to go to the shell and it was it + + align:start position:0% +I need to go to the shell and it was it + + + align:start position:0% +I need to go to the shell and it was it +was 335 what is it the 579 6-3 6-3 + + align:start position:0% +was 335 what is it the 579 6-3 6-3 + + + align:start position:0% +was 335 what is it the 579 6-3 6-3 +335 thousand and nine 949 okay so if I + + align:start position:0% +335 thousand and nine 949 okay so if I + + + align:start position:0% +335 thousand and nine 949 okay so if I +go off and I I run Sudoku optimized + + align:start position:0% +go off and I I run Sudoku optimized + + + align:start position:0% +go off and I I run Sudoku optimized +which is doing these implications like I + + align:start position:0% +which is doing these implications like I + + + align:start position:0% +which is doing these implications like I +described and and I go ahead and run + + align:start position:0% +described and and I go ahead and run + + + align:start position:0% +described and and I go ahead and run +that the first one goes from 579 233 + + align:start position:0% +that the first one goes from 579 233 + + + align:start position:0% +that the first one goes from 579 233 +backtracks okay so so that's pretty good + + align:start position:0% +backtracks okay so so that's pretty good + + + align:start position:0% +backtracks okay so so that's pretty good +it because it's done a bunch of + + align:start position:0% +it because it's done a bunch of + + + align:start position:0% +it because it's done a bunch of +implications it's still it's it's not + + align:start position:0% +implications it's still it's it's not + + + align:start position:0% +implications it's still it's it's not +super smart I mean that is a simple + + align:start position:0% +super smart I mean that is a simple + + + align:start position:0% +super smart I mean that is a simple +enough puzzle that a human being would + + align:start position:0% +enough puzzle that a human being would + + + align:start position:0% +enough puzzle that a human being would +not backtrack I mean a human being would + + align:start position:0% +not backtrack I mean a human being would + + + align:start position:0% +not backtrack I mean a human being would +not backtrack in that first puzzle right + + align:start position:0% +not backtrack in that first puzzle right + + + align:start position:0% +not backtrack in that first puzzle right +and you should you should check check + + align:start position:0% +and you should you should check check + + + align:start position:0% +and you should you should check check +that and oh this thing finished in the + + align:start position:0% +that and oh this thing finished in the + + + align:start position:0% +that and oh this thing finished in the +middle so it went to 33 only had three + + align:start position:0% +middle so it went to 33 only had three + + + align:start position:0% +middle so it went to 33 only had three +of them what do I have here instead I'll + + align:start position:0% +of them what do I have here instead I'll + + + align:start position:0% +of them what do I have here instead I'll +go opt + + align:start position:0% + + + + align:start position:0% + +oh I see I only ran oh wow + + align:start position:0% +oh I see I only ran oh wow + + + align:start position:0% +oh I see I only ran oh wow +okay so I ran into hard and difficult so + + align:start position:0% +okay so I ran into hard and difficult so + + + align:start position:0% +okay so I ran into hard and difficult so +it really went from 6-3 6-3 to 33 it + + align:start position:0% +it really went from 6-3 6-3 to 33 it + + + align:start position:0% +it really went from 6-3 6-3 to 33 it +went from 335 thousand to 24,000 and + + align:start position:0% +went from 335 thousand to 24,000 and + + + align:start position:0% +went from 335 thousand to 24,000 and +then it went to 720 from 1949 to 726 I + + align:start position:0% +then it went to 720 from 1949 to 726 I + + + align:start position:0% +then it went to 720 from 1949 to 726 I +mean the details aren't the numbers + + align:start position:0% +mean the details aren't the numbers + + + align:start position:0% +mean the details aren't the numbers +aren't super important don't hang your + + align:start position:0% +aren't super important don't hang your + + + align:start position:0% +aren't super important don't hang your +hat on them obviously if I change the + + align:start position:0% +hat on them obviously if I change the + + + align:start position:0% +hat on them obviously if I change the +code those numbers change but you can + + align:start position:0% +code those numbers change but you can + + + align:start position:0% +code those numbers change but you can +see that there's substantial gains to be + + align:start position:0% +see that there's substantial gains to be + + + align:start position:0% +see that there's substantial gains to be +had + + align:start position:0% +had + + + align:start position:0% +had +in terms of implications not making + + align:start position:0% +in terms of implications not making + + + align:start position:0% +in terms of implications not making +these dumb guesses that clearly are + + align:start position:0% +these dumb guesses that clearly are + + + align:start position:0% +these dumb guesses that clearly are +incorrect and that you you can fill in + + align:start position:0% +incorrect and that you you can fill in + + + align:start position:0% +incorrect and that you you can fill in +if you take away some of these empty + + align:start position:0% +if you take away some of these empty + + + align:start position:0% +if you take away some of these empty +squares then the depth of the recursion + + align:start position:0% +squares then the depth of the recursion + + + align:start position:0% +squares then the depth of the recursion +that you have to go through become + + align:start position:0% +that you have to go through become + + + align:start position:0% +that you have to go through become +substantially smaller and that's why + + align:start position:0% +substantially smaller and that's why + + + align:start position:0% +substantially smaller and that's why +your your backtracking is is simpler so + + align:start position:0% +your your backtracking is is simpler so + + + align:start position:0% +your your backtracking is is simpler so +I want to leave you with a couple of + + align:start position:0% +I want to leave you with a couple of + + + align:start position:0% +I want to leave you with a couple of +things I want to give you some sense for + + align:start position:0% +things I want to give you some sense for + + + align:start position:0% +things I want to give you some sense for +what particular implication that a + + align:start position:0% +what particular implication that a + + + align:start position:0% +what particular implication that a +strategy that we used and so I'll just + + align:start position:0% +strategy that we used and so I'll just + + + align:start position:0% +strategy that we used and so I'll just +put up make implications and give you + + align:start position:0% +put up make implications and give you + + + align:start position:0% +put up make implications and give you +some sense for how this works so the + + align:start position:0% +some sense for how this works so the + + + align:start position:0% +some sense for how this works so the +basic idea is that what I'm doing here + + align:start position:0% +basic idea is that what I'm doing here + + + align:start position:0% +basic idea is that what I'm doing here +is I'm looking at a particular sector + + align:start position:0% +is I'm looking at a particular sector + + + align:start position:0% +is I'm looking at a particular sector +and and I've created a data structure + + align:start position:0% +and and I've created a data structure + + + align:start position:0% +and and I've created a data structure +that says the missing elements here if I + + align:start position:0% +that says the missing elements here if I + + + align:start position:0% +that says the missing elements here if I +put a two in here let's just say I go + + align:start position:0% +put a two in here let's just say I go + + + align:start position:0% +put a two in here let's just say I go +ahead and put a two in here the missing + + align:start position:0% +ahead and put a two in here the missing + + + align:start position:0% +ahead and put a two in here the missing +elements here are our the set is three + + align:start position:0% +elements here are our the set is three + + + align:start position:0% +elements here are our the set is three +four five six seven and nine all right + + align:start position:0% +four five six seven and nine all right + + + align:start position:0% +four five six seven and nine all right +so this could be three four five six + + align:start position:0% +so this could be three four five six + + + align:start position:0% +so this could be three four five six +seven eight nine this could be three + + align:start position:0% +seven eight nine this could be three + + + align:start position:0% +seven eight nine this could be three +four five six seven eight nine and this + + align:start position:0% +four five six seven eight nine and this + + + align:start position:0% +four five six seven eight nine and this +is quite dumb right now but each of + + align:start position:0% +is quite dumb right now but each of + + + align:start position:0% +is quite dumb right now but each of +these different squares could be three + + align:start position:0% +these different squares could be three + + + align:start position:0% +these different squares could be three +four five six seven eight nine okay + + align:start position:0% +four five six seven eight nine okay + + + align:start position:0% +four five six seven eight nine okay +possibly all right and then I say so + + align:start position:0% +possibly all right and then I say so + + + align:start position:0% +possibly all right and then I say so +that's the first part of the code and + + align:start position:0% +that's the first part of the code and + + + align:start position:0% +that's the first part of the code and +then I say I'm gonna attach essentially + + align:start position:0% +then I say I'm gonna attach essentially + + + align:start position:0% +then I say I'm gonna attach essentially +a copy of this set to each of the + + align:start position:0% +a copy of this set to each of the + + + align:start position:0% +a copy of this set to each of the +missing squares and then I'm going to go + + align:start position:0% +missing squares and then I'm going to go + + + align:start position:0% +missing squares and then I'm going to go +through and find the missing elements so + + align:start position:0% +through and find the missing elements so + + + align:start position:0% +through and find the missing elements so +so this thing here can be a nine because + + align:start position:0% +so this thing here can be a nine because + + + align:start position:0% +so this thing here can be a nine because +I see a nine here it can be a three + + align:start position:0% +I see a nine here it can be a three + + + align:start position:0% +I see a nine here it can be a three +right + + align:start position:0% +right + + + align:start position:0% +right +so I can take this thing here and I'd + + align:start position:0% +so I can take this thing here and I'd + + + align:start position:0% +so I can take this thing here and I'd +take away that at the nine and then take + + align:start position:0% +take away that at the nine and then take + + + align:start position:0% +take away that at the nine and then take +away the three and and I can do the same + + align:start position:0% +away the three and and I can do the same + + + align:start position:0% +away the three and and I can do the same +thing with that obviously I can also + + align:start position:0% +thing with that obviously I can also + + + align:start position:0% +thing with that obviously I can also +take away the the eight isn't there but + + align:start position:0% +take away the the eight isn't there but + + + align:start position:0% +take away the the eight isn't there but +I could take away the seven and I could + + align:start position:0% +I could take away the seven and I could + + + align:start position:0% +I could take away the seven and I could +take away the three the six and the one + + align:start position:0% +take away the three the six and the one + + + align:start position:0% +take away the three the six and the one +so I go ahead and I take away the six + + align:start position:0% +so I go ahead and I take away the six + + + align:start position:0% +so I go ahead and I take away the six +and the three was already take taken out + + align:start position:0% +and the three was already take taken out + + + align:start position:0% +and the three was already take taken out +and I keep doing this and I try and + + align:start position:0% +and I keep doing this and I try and + + + align:start position:0% +and I keep doing this and I try and +shrink the possibilities corresponding + + align:start position:0% +shrink the possibilities corresponding + + + align:start position:0% +shrink the possibilities corresponding +to this particular square the curtain + + align:start position:0% +to this particular square the curtain + + + align:start position:0% +to this particular square the curtain +that has the set of different + + align:start position:0% +that has the set of different + + + align:start position:0% +that has the set of different +possibilities and if I ever so when can + + align:start position:0% +possibilities and if I ever so when can + + + align:start position:0% +possibilities and if I ever so when can +I make an implication what is the + + align:start position:0% +I make an implication what is the + + + align:start position:0% +I make an implication what is the +condition that is going to let me make + + align:start position:0% +condition that is going to let me make + + + align:start position:0% +condition that is going to let me make +an implication when I take this set of + + align:start position:0% +an implication when I take this set of + + + align:start position:0% +an implication when I take this set of +numbers and I start shrinking them down + + align:start position:0% +numbers and I start shrinking them down + + + align:start position:0% +numbers and I start shrinking them down +using these rules that I have over on + + align:start position:0% +using these rules that I have over on + + + align:start position:0% +using these rules that I have over on +the the right hand side there what what + + align:start position:0% +the the right hand side there what what + + + align:start position:0% +the the right hand side there what what +is an implication what does that + + align:start position:0% +is an implication what does that + + + align:start position:0% +is an implication what does that +correspond to in relation to the size in + + align:start position:0% +correspond to in relation to the size in + + + align:start position:0% +correspond to in relation to the size in +relation to the set right yeah behind + + align:start position:0% +relation to the set right yeah behind + + + align:start position:0% +relation to the set right yeah behind +you right that's exactly right + + align:start position:0% +you right that's exactly right + + + align:start position:0% +you right that's exactly right +if you have one element in this set then + + align:start position:0% +if you have one element in this set then + + + align:start position:0% +if you have one element in this set then +that's an implication if I have two + + align:start position:0% +that's an implication if I have two + + + align:start position:0% +that's an implication if I have two +elements in the set it's not implication + + align:start position:0% +elements in the set it's not implication + + + align:start position:0% +elements in the set it's not implication +because I don't quite know what you do + + align:start position:0% +because I don't quite know what you do + + + align:start position:0% +because I don't quite know what you do +there but if I had one element in the + + align:start position:0% +there but if I had one element in the + + + align:start position:0% +there but if I had one element in the +set that's an implication and that's it + + align:start position:0% +set that's an implication and that's it + + + align:start position:0% +set that's an implication and that's it +that said you know this code is not + + align:start position:0% +that said you know this code is not + + + align:start position:0% +that said you know this code is not +complicated check if the V set is a + + align:start position:0% +complicated check if the V set is a + + + align:start position:0% +complicated check if the V set is a +single turn which is a single element + + align:start position:0% +single turn which is a single element + + + align:start position:0% +single turn which is a single element +and I'm going to go ahead and append to + + align:start position:0% +and I'm going to go ahead and append to + + + align:start position:0% +and I'm going to go ahead and append to +this implication which is a very + + align:start position:0% +this implication which is a very + + + align:start position:0% +this implication which is a very +straightforward data structure that says + + align:start position:0% +straightforward data structure that says + + + align:start position:0% +straightforward data structure that says +this is the grid location I grid + + align:start position:0% +this is the grid location I grid + + + align:start position:0% +this is the grid location I grid +location J and this is the value that + + align:start position:0% +location J and this is the value that + + + align:start position:0% +location J and this is the value that +was implied by that all right so not + + align:start position:0% +was implied by that all right so not + + + align:start position:0% +was implied by that all right so not +only do I have I J E which is the which + + align:start position:0% +only do I have I J E which is the which + + + align:start position:0% +only do I have I J E which is the which +is the original guess that I have I also + + align:start position:0% +is the original guess that I have I also + + + align:start position:0% +is the original guess that I have I also +have you know kind of a bunch of other + + align:start position:0% +have you know kind of a bunch of other + + + align:start position:0% +have you know kind of a bunch of other +tuples corresponding to different + + align:start position:0% +tuples corresponding to different + + + align:start position:0% +tuples corresponding to different +coordinates + + align:start position:0% +coordinates + + + align:start position:0% +coordinates +you know k ik l coordinates and the + + align:start position:0% +you know k ik l coordinates and the + + + align:start position:0% +you know k ik l coordinates and the +value call it V associated with that and + + align:start position:0% +value call it V associated with that and + + + align:start position:0% +value call it V associated with that and +these are all the different implications + + align:start position:0% +these are all the different implications + + + align:start position:0% +these are all the different implications +that I can collect together in this list + + align:start position:0% +that I can collect together in this list + + + align:start position:0% +that I can collect together in this list +and I can just add those things in to + + align:start position:0% +and I can just add those things in to + + + align:start position:0% +and I can just add those things in to +make implications and then I keep going + + align:start position:0% +make implications and then I keep going + + + align:start position:0% +make implications and then I keep going +and then if I ever realize I've made a + + align:start position:0% +and then if I ever realize I've made a + + + align:start position:0% +and then if I ever realize I've made a +bad guess I have to undo everything by + + align:start position:0% +bad guess I have to undo everything by + + + align:start position:0% +bad guess I have to undo everything by +zeroing them all out which is making + + align:start position:0% +zeroing them all out which is making + + + align:start position:0% +zeroing them all out which is making +them all empty all right so one thing + + align:start position:0% +them all empty all right so one thing + + + align:start position:0% +them all empty all right so one thing +that this code does and you can you can + + align:start position:0% +that this code does and you can you can + + + align:start position:0% +that this code does and you can you can +take a look at it and I would encourage + + align:start position:0% +take a look at it and I would encourage + + + align:start position:0% +take a look at it and I would encourage +you to do the first exercise which is + + align:start position:0% +you to do the first exercise which is + + + align:start position:0% +you to do the first exercise which is +taking these implications and making + + align:start position:0% +taking these implications and making + + + align:start position:0% +taking these implications and making +them a little more powerful by adding + + align:start position:0% +them a little more powerful by adding + + + align:start position:0% +them a little more powerful by adding +like three or four lines occurred to + + align:start position:0% +like three or four lines occurred to + + + align:start position:0% +like three or four lines occurred to +this + + align:start position:0% +this + + + align:start position:0% +this +this code and exactly what you have to + + align:start position:0% +this code and exactly what you have to + + + align:start position:0% +this code and exactly what you have to +do in this exercise and I'll show you + + align:start position:0% +do in this exercise and I'll show you + + + align:start position:0% +do in this exercise and I'll show you +what the results should be in in just a + + align:start position:0% +what the results should be in in just a + + + align:start position:0% +what the results should be in in just a +minute but let me just spend 30 seconds + + align:start position:0% +minute but let me just spend 30 seconds + + + align:start position:0% +minute but let me just spend 30 seconds +explaining to you how you could do a + + align:start position:0% +explaining to you how you could do a + + + align:start position:0% +explaining to you how you could do a +little bit better than what this code + + align:start position:0% +little bit better than what this code + + + align:start position:0% +little bit better than what this code +does so what I've described to you + + align:start position:0% +does so what I've described to you + + + align:start position:0% +does so what I've described to you +really is this get this set you know + + align:start position:0% +really is this get this set you know + + + align:start position:0% +really is this get this set you know +imply get a single term etc and then you + + align:start position:0% +imply get a single term etc and then you + + + align:start position:0% +imply get a single term etc and then you +can do this obviously for each of these + + align:start position:0% +can do this obviously for each of these + + + align:start position:0% +can do this obviously for each of these +sectors and that's what this does you + + align:start position:0% +sectors and that's what this does you + + + align:start position:0% +sectors and that's what this does you +had a for loop up there that does it for + + align:start position:0% +had a for loop up there that does it for + + + align:start position:0% +had a for loop up there that does it for +each of the sectors right grab a sector + + align:start position:0% +each of the sectors right grab a sector + + + align:start position:0% +each of the sectors right grab a sector +and go ahead and do an implication for + + align:start position:0% +and go ahead and do an implication for + + + align:start position:0% +and go ahead and do an implication for +that sector now this code just runs + + align:start position:0% +that sector now this code just runs + + + align:start position:0% +that sector now this code just runs +through the sectors you know 1 2 3 4 5 6 + + align:start position:0% +through the sectors you know 1 2 3 4 5 6 + + + align:start position:0% +through the sectors you know 1 2 3 4 5 6 +7 8 9 and then discovers the + + align:start position:0% +7 8 9 and then discovers the + + + align:start position:0% +7 8 9 and then discovers the +implications if they exist adds them to + + align:start position:0% +implications if they exist adds them to + + + align:start position:0% +implications if they exist adds them to +the apply list and then throws up his + + align:start position:0% +the apply list and then throws up his + + + align:start position:0% +the apply list and then throws up his +hands and says I'm tired I'm done I + + align:start position:0% +hands and says I'm tired I'm done I + + + align:start position:0% +hands and says I'm tired I'm done I +don't want to do any more ok what could + + align:start position:0% +don't want to do any more ok what could + + + align:start position:0% +don't want to do any more ok what could +you do that's an improvement + + align:start position:0% +you do that's an improvement + + + align:start position:0% +you do that's an improvement +given what we have described and what + + align:start position:0% +given what we have described and what + + + align:start position:0% +given what we have described and what +I've told you so far what is an + + align:start position:0% +I've told you so far what is an + + + align:start position:0% +I've told you so far what is an +incremental improvement over going over + + align:start position:0% +incremental improvement over going over + + + align:start position:0% +incremental improvement over going over +these sectors once and doing these + + align:start position:0% +these sectors once and doing these + + + align:start position:0% +these sectors once and doing these +implications and storing them and moving + + align:start position:0% +implications and storing them and moving + + + align:start position:0% +implications and storing them and moving +on what was an incremental improvement + + align:start position:0% + + + + align:start position:0% + +exactly you don't have to stop right + + align:start position:0% +exactly you don't have to stop right + + + align:start position:0% +exactly you don't have to stop right +there's no reason to stop if you're + + align:start position:0% +there's no reason to stop if you're + + + align:start position:0% +there's no reason to stop if you're +implying right once you put something in + + align:start position:0% +implying right once you put something in + + + align:start position:0% +implying right once you put something in +here and you've gone through 1 2 3 4 5 6 + + align:start position:0% +here and you've gone through 1 2 3 4 5 6 + + + align:start position:0% +here and you've gone through 1 2 3 4 5 6 +7 8 9 got the implications you can put + + align:start position:0% +7 8 9 got the implications you can put + + + align:start position:0% +7 8 9 got the implications you can put +them into the grid and then start over + + align:start position:0% +them into the grid and then start over + + + align:start position:0% +them into the grid and then start over +again 1 2 3 4 that's what humans do + + align:start position:0% +again 1 2 3 4 that's what humans do + + + align:start position:0% +again 1 2 3 4 that's what humans do +right when humans put something in and + + align:start position:0% +right when humans put something in and + + + align:start position:0% +right when humans put something in and +they don't stop they just keep going + + align:start position:0% +they don't stop they just keep going + + + align:start position:0% +they don't stop they just keep going +until they get to the end right now + + align:start position:0% +until they get to the end right now + + + align:start position:0% +until they get to the end right now +first all of these implications are + + align:start position:0% +first all of these implications are + + + align:start position:0% +first all of these implications are +could be incorrect if that first guess + + align:start position:0% +could be incorrect if that first guess + + + align:start position:0% +could be incorrect if that first guess +was incorrect there's no there's no + + align:start position:0% +was incorrect there's no there's no + + + align:start position:0% +was incorrect there's no there's no +change there but there's nothing that's + + align:start position:0% +change there but there's nothing that's + + + align:start position:0% +change there but there's nothing that's +stopping you from from turning this this + + align:start position:0% +stopping you from from turning this this + + + align:start position:0% +stopping you from from turning this this +little thing there's a loop here that + + align:start position:0% +little thing there's a loop here that + + + align:start position:0% +little thing there's a loop here that +simply corresponds to making a pass over + + align:start position:0% +simply corresponds to making a pass over + + + align:start position:0% +simply corresponds to making a pass over +the sector's but you can put this whole + + align:start position:0% +the sector's but you can put this whole + + + align:start position:0% +the sector's but you can put this whole +thing into a loop and and you keep going + + align:start position:0% +thing into a loop and and you keep going + + + align:start position:0% +thing into a loop and and you keep going +through the loop until you've you + + align:start position:0% +through the loop until you've you + + + align:start position:0% +through the loop until you've you +basically have no change that happens in + + align:start position:0% +basically have no change that happens in + + + align:start position:0% +basically have no change that happens in +your in your grid ok so that's four + + align:start position:0% +your in your grid ok so that's four + + + align:start position:0% +your in your grid ok so that's four +lines of code and I'm not going to show + + align:start position:0% +lines of code and I'm not going to show + + + align:start position:0% +lines of code and I'm not going to show +you what those four lines of code look + + align:start position:0% +you what those four lines of code look + + + align:start position:0% +you what those four lines of code look +like so close your eyes in case it's a + + align:start position:0% + + + + align:start position:0% + +and this is the solution to that code + + align:start position:0% +and this is the solution to that code + + + align:start position:0% +and this is the solution to that code +and I'm going to go ahead and run it and + + align:start position:0% +and I'm going to go ahead and run it and + + + align:start position:0% +and I'm going to go ahead and run it and +you saw what those numbers where with + + align:start position:0% +you saw what those numbers where with + + + align:start position:0% +you saw what those numbers where with +with respect to do the back tracks but + + align:start position:0% +with respect to do the back tracks but + + + align:start position:0% +with respect to do the back tracks but +if you do this extra implications the 33 + + align:start position:0% +if you do this extra implications the 33 + + + align:start position:0% +if you do this extra implications the 33 +went down to two okay for that example + + align:start position:0% +went down to two okay for that example + + + align:start position:0% +went down to two okay for that example +so this is not optimal because I wanted + + align:start position:0% +so this is not optimal because I wanted + + + align:start position:0% +so this is not optimal because I wanted +one right so if I wanted to be a human + + align:start position:0% +one right so if I wanted to be a human + + + align:start position:0% +one right so if I wanted to be a human +being that took this easy puzzle and + + align:start position:0% +being that took this easy puzzle and + + + align:start position:0% +being that took this easy puzzle and +just sort of went all the way without + + align:start position:0% +just sort of went all the way without + + + align:start position:0% +just sort of went all the way without +making any incorrect guesses I would be + + align:start position:0% +making any incorrect guesses I would be + + + align:start position:0% +making any incorrect guesses I would be +doing implications and that would go all + + align:start position:0% +doing implications and that would go all + + + align:start position:0% +doing implications and that would go all +the way and I got close with with two + + align:start position:0% +the way and I got close with with two + + + align:start position:0% +the way and I got close with with two +and I didn't print out the intermediate + + align:start position:0% +and I didn't print out the intermediate + + + align:start position:0% +and I didn't print out the intermediate +ones but the 24,000 went down to 11,000 + + align:start position:0% +ones but the 24,000 went down to 11,000 + + + align:start position:0% +ones but the 24,000 went down to 11,000 +and I forget what the last one was it + + align:start position:0% +and I forget what the last one was it + + + align:start position:0% +and I forget what the last one was it +went down right so with four lines of + + align:start position:0% +went down right so with four lines of + + + align:start position:0% +went down right so with four lines of +code and with the optimized code that + + align:start position:0% +code and with the optimized code that + + + align:start position:0% +code and with the optimized code that +I'll put up you should be able to get + + align:start position:0% +I'll put up you should be able to get + + + align:start position:0% +I'll put up you should be able to get +those numbers in your in your first + + align:start position:0% +those numbers in your in your first + + + align:start position:0% +those numbers in your in your first +exercise or you could solve diagonal + + align:start position:0% +exercise or you could solve diagonal + + + align:start position:0% +exercise or you could solve diagonal +Sudoku or even Sudoku or you could spend + + align:start position:0% +Sudoku or even Sudoku or you could spend + + + align:start position:0% +Sudoku or even Sudoku or you could spend +the rest of the day coding whatever you + + align:start position:0% +the rest of the day coding whatever you + + + align:start position:0% +the rest of the day coding whatever you +want whatever all right see you next + + align:start position:0% +want whatever all right see you next + + + align:start position:0% +want whatever all right see you next +time + + align:start position:0% + + + + align:start position:0% + +you \ No newline at end of file diff --git a/bTyxpoi2dmM.txt b/bTyxpoi2dmM.txt new file mode 100644 index 0000000000000000000000000000000000000000..049669cd5ad429b51231f46ed3b937fc94196c01 --- /dev/null +++ b/bTyxpoi2dmM.txt @@ -0,0 +1,12181 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer high quality educational + + align:start position:0% +to offer high quality educational + + + align:start position:0% +to offer high quality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +view additional materials from hundreds + + align:start position:0% +view additional materials from hundreds + + + align:start position:0% +view additional materials from hundreds +of MIT courses visit MIT open courseware + + align:start position:0% +of MIT courses visit MIT open courseware + + + align:start position:0% +of MIT courses visit MIT open courseware +at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu So today we're going to talk + + align:start position:0% +ocw.mit.edu So today we're going to talk + + + align:start position:0% +ocw.mit.edu So today we're going to talk +about uh communication + + align:start position:0% +about uh communication + + + align:start position:0% +about uh communication +networks communication networks is a + + align:start position:0% +networks communication networks is a + + + align:start position:0% +networks communication networks is a +great application of graph Theory so + + align:start position:0% +great application of graph Theory so + + + align:start position:0% +great application of graph Theory so +what we're going to study is uh how do + + align:start position:0% +what we're going to study is uh how do + + + align:start position:0% +what we're going to study is uh how do +you route packets through networks so + + align:start position:0% +you route packets through networks so + + + align:start position:0% +you route packets through networks so +you have the internet which is a geotic + + align:start position:0% +you have the internet which is a geotic + + + align:start position:0% +you have the internet which is a geotic +network it's not organized we are + + align:start position:0% +network it's not organized we are + + + align:start position:0% +network it's not organized we are +interested in highly structured networks + + align:start position:0% +interested in highly structured networks + + + align:start position:0% +interested in highly structured networks +and you can find them for example in + + align:start position:0% +and you can find them for example in + + + align:start position:0% +and you can find them for example in +parallel computers where you want to + + align:start position:0% +parallel computers where you want to + + + align:start position:0% +parallel computers where you want to +Route um uh the data flow you can find + + align:start position:0% +Route um uh the data flow you can find + + + align:start position:0% +Route um uh the data flow you can find +them in uh certain telephone switch uh + + align:start position:0% +them in uh certain telephone switch uh + + + align:start position:0% +them in uh certain telephone switch uh +um um uh networks and so on so we're + + align:start position:0% +um um uh networks and so on so we're + + + align:start position:0% +um um uh networks and so on so we're +going to talk about few a few very + + align:start position:0% +going to talk about few a few very + + + align:start position:0% +going to talk about few a few very +special ones binary trees and then + + align:start position:0% +special ones binary trees and then + + + align:start position:0% +special ones binary trees and then +slowly we will figure out what all these + + align:start position:0% +slowly we will figure out what all these + + + align:start position:0% +slowly we will figure out what all these +performance measures really mean this + + align:start position:0% +performance measures really mean this + + + align:start position:0% +performance measures really mean this +one has to do with latency we have + + align:start position:0% +one has to do with latency we have + + + align:start position:0% +one has to do with latency we have +switches their size the number of them + + align:start position:0% +switches their size the number of them + + + align:start position:0% +switches their size the number of them +congestion and then we will slowly get + + align:start position:0% +congestion and then we will slowly get + + + align:start position:0% +congestion and then we will slowly get +down to Ben's Network which is a really + + align:start position:0% +down to Ben's Network which is a really + + + align:start position:0% +down to Ben's Network which is a really +beautiful network with beautiful uh + + align:start position:0% +beautiful network with beautiful uh + + + align:start position:0% +beautiful network with beautiful uh +parameters and we're going to prove + + align:start position:0% +parameters and we're going to prove + + + align:start position:0% +parameters and we're going to prove +those so + + align:start position:0% +those so + + + align:start position:0% +those so +um let's start off with uh the first one + + align:start position:0% +um let's start off with uh the first one + + + align:start position:0% +um let's start off with uh the first one +the complete binary tree and let me draw + + align:start position:0% +the complete binary tree and let me draw + + + align:start position:0% +the complete binary tree and let me draw +it for + + align:start position:0% + + + + align:start position:0% + +you in this uh Network we will have um + + align:start position:0% +you in this uh Network we will have um + + + align:start position:0% +you in this uh Network we will have um +uh a root and let me just draw it first + + align:start position:0% +uh a root and let me just draw it first + + + align:start position:0% +uh a root and let me just draw it first +we have uh fases that uh represent here + + align:start position:0% +we have uh fases that uh represent here + + + align:start position:0% +we have uh fases that uh represent here +the switches so these C CES let me + + align:start position:0% +the switches so these C CES let me + + + align:start position:0% +the switches so these C CES let me +explain it over + + align:start position:0% +explain it over + + + align:start position:0% +explain it over +here actually represent a switch and the + + align:start position:0% +here actually represent a switch and the + + + align:start position:0% +here actually represent a switch and the +idea is that these actually + + align:start position:0% +idea is that these actually + + + align:start position:0% +idea is that these actually +direct um uh + + align:start position:0% +direct um uh + + + align:start position:0% +direct um uh +packets through the + + align:start position:0% + + + + align:start position:0% + +network and these packets are fixed + + align:start position:0% +network and these packets are fixed + + + align:start position:0% +network and these packets are fixed +sized uh packets of data so like I don't + + align:start position:0% +sized uh packets of data so like I don't + + + align:start position:0% +sized uh packets of data so like I don't +know say 4,000 uh bytes or or or bits or + + align:start position:0% +know say 4,000 uh bytes or or or bits or + + + align:start position:0% +know say 4,000 uh bytes or or or bits or +whatever the network wants you to comply + + align:start position:0% +whatever the network wants you to comply + + + align:start position:0% +whatever the network wants you to comply +to so these are fixed sites pieces of + + align:start position:0% +to so these are fixed sites pieces of + + + align:start position:0% +to so these are fixed sites pieces of +data so what we want is we want to uh be + + align:start position:0% +data so what we want is we want to uh be + + + align:start position:0% +data so what we want is we want to uh be +able from every terminal and a terminal + + align:start position:0% +able from every terminal and a terminal + + + align:start position:0% +able from every terminal and a terminal +I will denote by a square from every + + align:start position:0% +I will denote by a square from every + + + align:start position:0% +I will denote by a square from every +terminal I want to be able to uh reach + + align:start position:0% +terminal I want to be able to uh reach + + + align:start position:0% +terminal I want to be able to uh reach +any other terminal so what is a terminal + + align:start position:0% +any other terminal so what is a terminal + + + align:start position:0% +any other terminal so what is a terminal +terminal is like a computer or something + + align:start position:0% +terminal is like a computer or something + + + align:start position:0% +terminal is like a computer or something +like that it's uh it's it's actually the + + align:start position:0% +like that it's uh it's it's actually the + + + align:start position:0% +like that it's uh it's it's actually the +source and the + + align:start position:0% + + + + align:start position:0% + +destination of + + align:start position:0% + + + + align:start position:0% + +data so what we're looking for is how + + align:start position:0% +data so what we're looking for is how + + + align:start position:0% +data so what we're looking for is how +can we route how we can find a network + + align:start position:0% +can we route how we can find a network + + + align:start position:0% +can we route how we can find a network +of switches that are connected through + + align:start position:0% +of switches that are connected through + + + align:start position:0% +of switches that are connected through +wires fibers or yeah it's the + + align:start position:0% +wires fibers or yeah it's the + + + align:start position:0% +wires fibers or yeah it's the +question top of theut + + align:start position:0% +question top of theut + + + align:start position:0% +question top of theut +off one oh sorry okay thank you um so + + align:start position:0% +off one oh sorry okay thank you um so + + + align:start position:0% +off one oh sorry okay thank you um so +what we want is we want to uh route uh + + align:start position:0% +what we want is we want to uh route uh + + + align:start position:0% +what we want is we want to uh route uh +packets that come from any terminal to + + align:start position:0% +packets that come from any terminal to + + + align:start position:0% +packets that come from any terminal to +any other terminal that is what our goal + + align:start position:0% +any other terminal that is what our goal + + + align:start position:0% +any other terminal that is what our goal +is and we want to uh make sure that that + + align:start position:0% +is and we want to uh make sure that that + + + align:start position:0% +is and we want to uh make sure that that +is efficient so the first one is this + + align:start position:0% +is efficient so the first one is this + + + align:start position:0% +is efficient so the first one is this +binary tree and let's uh + + align:start position:0% +binary tree and let's uh + + + align:start position:0% +binary tree and let's uh +um see how this may work we may have + + align:start position:0% +um see how this may work we may have + + + align:start position:0% +um see how this may work we may have +switches that actually + + align:start position:0% + + + + align:start position:0% + +um that actually have uh inputs coming + + align:start position:0% +um that actually have uh inputs coming + + + align:start position:0% +um that actually have uh inputs coming +from a + + align:start position:0% + + + + align:start position:0% + +Terminals and the switches may also + + align:start position:0% +Terminals and the switches may also + + + align:start position:0% +Terminals and the switches may also +output to terminals these are here at + + align:start position:0% +output to terminals these are here at + + + align:start position:0% +output to terminals these are here at +the bottom at this side we have a + + align:start position:0% +the bottom at this side we have a + + + align:start position:0% +the bottom at this side we have a +similar uh structure this is the root of + + align:start position:0% +similar uh structure this is the root of + + + align:start position:0% +similar uh structure this is the root of +the tree we have another switch over + + align:start position:0% +the tree we have another switch over + + + align:start position:0% +the tree we have another switch over +here we call go down we go up here and + + align:start position:0% +here we call go down we go up here and + + + align:start position:0% +here we call go down we go up here and +once more like this and again we have + + align:start position:0% +once more like this and again we have + + + align:start position:0% +once more like this and again we have +oops we have input coming in or an + + align:start position:0% +oops we have input coming in or an + + + align:start position:0% +oops we have input coming in or an +output coming + + align:start position:0% +output coming + + + align:start position:0% +output coming +out to their respective + + align:start position:0% + + + + align:start position:0% + +terminals so what is happening here is + + align:start position:0% +terminals so what is happening here is + + + align:start position:0% +terminals so what is happening here is +that uh I would like to have an + + align:start position:0% +that uh I would like to have an + + + align:start position:0% +that uh I would like to have an +input say input zero wants to travel all + + align:start position:0% +input say input zero wants to travel all + + + align:start position:0% +input say input zero wants to travel all +the way over to say the output that is + + align:start position:0% +the way over to say the output that is + + + align:start position:0% +the way over to say the output that is +present over here so let me label these + + align:start position:0% +present over here so let me label these + + + align:start position:0% +present over here so let me label these +so we have the output zero input + + align:start position:0% +so we have the output zero input + + + align:start position:0% +so we have the output zero input +one output + + align:start position:0% +one output + + + align:start position:0% +one output +one input two and output + + align:start position:0% +one input two and output + + + align:start position:0% +one input two and output +two input uh three and output + + align:start position:0% +two input uh three and output + + + align:start position:0% +two input uh three and output +four + + align:start position:0% +four + + + align:start position:0% +four +so uh well I can definitely reach every + + align:start position:0% +so uh well I can definitely reach every + + + align:start position:0% +so uh well I can definitely reach every +single output from any in put so that's + + align:start position:0% +single output from any in put so that's + + + align:start position:0% +single output from any in put so that's +great so this looks like uh something + + align:start position:0% +great so this looks like uh something + + + align:start position:0% +great so this looks like uh something +that you are familiar with right it's + + align:start position:0% +that you are familiar with right it's + + + align:start position:0% +that you are familiar with right it's +like just a tree we have essentially + + align:start position:0% +like just a tree we have essentially + + + align:start position:0% +like just a tree we have essentially +it's a directed tree but but I mean it's + + align:start position:0% +it's a directed tree but but I mean it's + + + align:start position:0% +it's a directed tree but but I mean it's +a directed graph but these edges go in + + align:start position:0% +a directed graph but these edges go in + + + align:start position:0% +a directed graph but these edges go in +both directions right so I have an edge + + align:start position:0% +both directions right so I have an edge + + + align:start position:0% +both directions right so I have an edge +that goes from here to here and back + + align:start position:0% +that goes from here to here and back + + + align:start position:0% +that goes from here to here and back +from here to here so this is the kind of + + align:start position:0% +from here to here so this is the kind of + + + align:start position:0% +from here to here so this is the kind of +layout that you could try out first to + + align:start position:0% +layout that you could try out first to + + + align:start position:0% +layout that you could try out first to +see whether this type of network would + + align:start position:0% +see whether this type of network would + + + align:start position:0% +see whether this type of network would +lead to good + + align:start position:0% +lead to good + + + align:start position:0% +lead to good +performance so let's uh have a look at + + align:start position:0% +performance so let's uh have a look at + + + align:start position:0% +performance so let's uh have a look at +the different parameters and see uh how + + align:start position:0% +the different parameters and see uh how + + + align:start position:0% +the different parameters and see uh how +well this behaves so here we have a few + + align:start position:0% +well this behaves so here we have a few + + + align:start position:0% +well this behaves so here we have a few +parameters that we build that we will be + + align:start position:0% +parameters that we build that we will be + + + align:start position:0% +parameters that we build that we will be +talking + + align:start position:0% +talking + + + align:start position:0% +talking +about um so first of all let's talk + + align:start position:0% +about um so first of all let's talk + + + align:start position:0% +about um so first of all let's talk +about uh the + + align:start position:0% +about uh the + + + align:start position:0% +about uh the +latency in this particular Network so + + align:start position:0% +latency in this particular Network so + + + align:start position:0% +latency in this particular Network so +how are we going to measure + + align:start position:0% +how are we going to measure + + + align:start position:0% +how are we going to measure +this well we're going to look at this + + align:start position:0% +this well we're going to look at this + + + align:start position:0% +this well we're going to look at this +graph and we're going to measure it by + + align:start position:0% +graph and we're going to measure it by + + + align:start position:0% +graph and we're going to measure it by +the number of wires that you need to go + + align:start position:0% +the number of wires that you need to go + + + align:start position:0% +the number of wires that you need to go +through from an input to an output + + align:start position:0% +through from an input to an output + + + align:start position:0% +through from an input to an output +so let me write this + + align:start position:0% + + + + align:start position:0% + +down so the + + align:start position:0% +down so the + + + align:start position:0% +down so the +latency is the time that is + + align:start position:0% + + + + align:start position:0% + +required uh for a packet to + + align:start position:0% + + + + align:start position:0% + +travel um to + + align:start position:0% +travel um to + + + align:start position:0% +travel um to +travel from an input to an output + + align:start position:0% + + + + align:start position:0% + +and how are we going to measure this + + align:start position:0% +and how are we going to measure this + + + align:start position:0% +and how are we going to measure this +well we're just going to measure this by + + align:start position:0% +well we're just going to measure this by + + + align:start position:0% +well we're just going to measure this by +the number of wires that we need to go + + align:start position:0% +the number of wires that we need to go + + + align:start position:0% +the number of wires that we need to go +through so this you have seen before we + + align:start position:0% +through so this you have seen before we + + + align:start position:0% +through so this you have seen before we +can measure this by the diameter of that + + align:start position:0% +can measure this by the diameter of that + + + align:start position:0% +can measure this by the diameter of that +particular graph so here we will Define + + align:start position:0% +particular graph so here we will Define + + + align:start position:0% +particular graph so here we will Define +it for a network so the diameter of a + + align:start position:0% + + + + align:start position:0% + +network is going to be the length + + align:start position:0% + + + + align:start position:0% + +of the shortest + + align:start position:0% + + + + align:start position:0% + +path + + align:start position:0% + + + + align:start position:0% + +between between the input and + + align:start position:0% + + + + align:start position:0% + +output that are furthest + + align:start position:0% +output that are furthest + + + align:start position:0% +output that are furthest +apart so let's have a look at the uh + + align:start position:0% +apart so let's have a look at the uh + + + align:start position:0% +apart so let's have a look at the uh +graph of + + align:start position:0% +graph of + + + align:start position:0% +graph of +above um so for + + align:start position:0% +above um so for + + + align:start position:0% +above um so for +example uh we can clearly see that for + + align:start position:0% +example uh we can clearly see that for + + + align:start position:0% +example uh we can clearly see that for +example input and output so say input + + align:start position:0% +example input and output so say input + + + align:start position:0% +example input and output so say input +zero and output one are connected by + + align:start position:0% +zero and output one are connected by + + + align:start position:0% +zero and output one are connected by +just going up uh one step over + + align:start position:0% + + + + align:start position:0% + +here but just going up from here to here + + align:start position:0% +here but just going up from here to here + + + align:start position:0% +here but just going up from here to here +then this switch forwards the packet to + + align:start position:0% +then this switch forwards the packet to + + + align:start position:0% +then this switch forwards the packet to +this switch this switch reroutes it + + align:start position:0% +this switch this switch reroutes it + + + align:start position:0% +this switch this switch reroutes it +forwards it over here and then it goes + + align:start position:0% +forwards it over here and then it goes + + + align:start position:0% +forwards it over here and then it goes +back to the output output one so for + + align:start position:0% +back to the output output one so for + + + align:start position:0% +back to the output output one so for +example this particular path only has + + align:start position:0% +example this particular path only has + + + align:start position:0% +example this particular path only has +one two three four uh edges and what + + align:start position:0% +one two three four uh edges and what + + + align:start position:0% +one two three four uh edges and what +we're interested in is uh sort of the + + align:start position:0% +we're interested in is uh sort of the + + + align:start position:0% +we're interested in is uh sort of the +worst case uh time that it requires to + + align:start position:0% +worst case uh time that it requires to + + + align:start position:0% +worst case uh time that it requires to +go from an input to an output so that + + align:start position:0% +go from an input to an output so that + + + align:start position:0% +go from an input to an output so that +means that we are interested in a + + align:start position:0% +means that we are interested in a + + + align:start position:0% +means that we are interested in a +diameter and a diameter is in this case + + align:start position:0% +diameter and a diameter is in this case + + + align:start position:0% +diameter and a diameter is in this case +well the shortest path that you can find + + align:start position:0% +well the shortest path that you can find + + + align:start position:0% +well the shortest path that you can find +from an input to uh to an outputs that + + align:start position:0% +from an input to uh to an outputs that + + + align:start position:0% +from an input to uh to an outputs that +are furthest apart so what are those who + + align:start position:0% +are furthest apart so what are those who + + + align:start position:0% +are furthest apart so what are those who +are furthest apart well of course you + + align:start position:0% +are furthest apart well of course you + + + align:start position:0% +are furthest apart well of course you +would like to go through here right so + + align:start position:0% +would like to go through here right so + + + align:start position:0% +would like to go through here right so +if I connect the input zero to say + + align:start position:0% +if I connect the input zero to say + + + align:start position:0% +if I connect the input zero to say +output four I will need go I will need + + align:start position:0% +output four I will need go I will need + + + align:start position:0% +output four I will need go I will need +to go all the way up through the root + + align:start position:0% +to go all the way up through the root + + + align:start position:0% +to go all the way up through the root +down to the output and how many edges do + + align:start position:0% +down to the output and how many edges do + + + align:start position:0% +down to the output and how many edges do +we see here one two three four five six + + align:start position:0% +we see here one two three four five six + + + align:start position:0% +we see here one two three four five six +so in this example we have a + + align:start position:0% +so in this example we have a + + + align:start position:0% +so in this example we have a +diameter that is equal to six and in + + align:start position:0% +diameter that is equal to six and in + + + align:start position:0% +diameter that is equal to six and in +General if you are looking at uh at u n + + align:start position:0% +General if you are looking at uh at u n + + + align:start position:0% +General if you are looking at uh at u n +* n network so what does that mean n is + + align:start position:0% +* n network so what does that mean n is + + + align:start position:0% +* n network so what does that mean n is +the number of inputs and N is also the + + align:start position:0% +the number of inputs and N is also the + + + align:start position:0% +the number of inputs and N is also the +number of outputs so in this case we + + align:start position:0% +number of outputs so in this case we + + + align:start position:0% +number of outputs so in this case we +have a four times this is actually three + + align:start position:0% +have a four times this is actually three + + + align:start position:0% +have a four times this is actually three +over + + align:start position:0% +over + + + align:start position:0% +over +here we have a four we have four inputs + + align:start position:0% +here we have a four we have four inputs + + + align:start position:0% +here we have a four we have four inputs +and four outputs so this particular + + align:start position:0% +and four outputs so this particular + + + align:start position:0% +and four outputs so this particular +example depicted on the board is a four + + align:start position:0% +example depicted on the board is a four + + + align:start position:0% +example depicted on the board is a four +* 4 Network so if you generalize this + + align:start position:0% +* 4 Network so if you generalize this + + + align:start position:0% +* 4 Network so if you generalize this +for any size binary tree um uh say in n + + align:start position:0% +for any size binary tree um uh say in n + + + align:start position:0% +for any size binary tree um uh say in n +* n network then how many uh yeah what's + + align:start position:0% +* n network then how many uh yeah what's + + + align:start position:0% +* n network then how many uh yeah what's +the diameter of this of of of such a + + align:start position:0% +the diameter of this of of of such a + + + align:start position:0% +the diameter of this of of of such a +general Network well if we have n inputs + + align:start position:0% +general Network well if we have n inputs + + + align:start position:0% +general Network well if we have n inputs +and N outputs well we have to go all the + + align:start position:0% +and N outputs well we have to go all the + + + align:start position:0% +and N outputs well we have to go all the +way up through towards the root and all + + align:start position:0% +way up through towards the root and all + + + align:start position:0% +way up through towards the root and all +the way down so we actually count the + + align:start position:0% +the way down so we actually count the + + + align:start position:0% +the way down so we actually count the +length of a leaf to the root here twice + + align:start position:0% +length of a leaf to the root here twice + + + align:start position:0% +length of a leaf to the root here twice +so in General we have a diameter that + + align:start position:0% +so in General we have a diameter that + + + align:start position:0% +so in General we have a diameter that +looks like + + align:start position:0% +looks like + + + align:start position:0% +looks like +this it's uh 2 + + align:start position:0% +this it's uh 2 + + + align:start position:0% +this it's uh 2 +* uh 1 plus the logarithm of n so in + + align:start position:0% +* uh 1 plus the logarithm of n so in + + + align:start position:0% +* uh 1 plus the logarithm of n so in +this uh lecture we will have + + align:start position:0% +this uh lecture we will have + + + align:start position:0% +this uh lecture we will have +n is going to be a power of + + align:start position:0% +n is going to be a power of + + + align:start position:0% +n is going to be a power of +two just to make calculations simple and + + align:start position:0% +two just to make calculations simple and + + + align:start position:0% +two just to make calculations simple and +uh the logarithm is always to the base + + align:start position:0% +uh the logarithm is always to the base + + + align:start position:0% +uh the logarithm is always to the base +two so this is the diameter of a general + + align:start position:0% +two so this is the diameter of a general + + + align:start position:0% +two so this is the diameter of a general +uh binary + + align:start position:0% +uh binary + + + align:start position:0% +uh binary +tree and uh well what are the other + + align:start position:0% +tree and uh well what are the other + + + align:start position:0% +tree and uh well what are the other +parameters so that does not look too bad + + align:start position:0% +parameters so that does not look too bad + + + align:start position:0% +parameters so that does not look too bad +I mean it's logarithmic in N so that + + align:start position:0% +I mean it's logarithmic in N so that + + + align:start position:0% +I mean it's logarithmic in N so that +sounds pretty good what about the switch + + align:start position:0% +sounds pretty good what about the switch + + + align:start position:0% +sounds pretty good what about the switch +sizes well how do I measure those it's + + align:start position:0% +sizes well how do I measure those it's + + + align:start position:0% +sizes well how do I measure those it's +like the number of inputs that get into + + align:start position:0% +like the number of inputs that get into + + + align:start position:0% +like the number of inputs that get into +it and the number of outputs that get + + align:start position:0% +it and the number of outputs that get + + + align:start position:0% +it and the number of outputs that get +out so in this case I will have one two + + align:start position:0% +out so in this case I will have one two + + + align:start position:0% +out so in this case I will have one two +inputs that go into this switch and + + align:start position:0% +inputs that go into this switch and + + + align:start position:0% +inputs that go into this switch and +there are two outputs coming out so this + + align:start position:0% +there are two outputs coming out so this + + + align:start position:0% +there are two outputs coming out so this +is what we call a 2 * 2 switch so this + + align:start position:0% +is what we call a 2 * 2 switch so this + + + align:start position:0% +is what we call a 2 * 2 switch so this +would be a 2 * 2 switch but if you look + + align:start position:0% +would be a 2 * 2 switch but if you look + + + align:start position:0% +would be a 2 * 2 switch but if you look +at this one for example we see one two + + align:start position:0% +at this one for example we see one two + + + align:start position:0% +at this one for example we see one two +three outgoing edges and one and and + + align:start position:0% +three outgoing edges and one and and + + + align:start position:0% +three outgoing edges and one and and +three ingoing edges so this is actually + + align:start position:0% +three ingoing edges so this is actually + + + align:start position:0% +three ingoing edges so this is actually +a three * three + + align:start position:0% +a three * three + + + align:start position:0% +a three * three +switch and uh in a general binary tree + + align:start position:0% +switch and uh in a general binary tree + + + align:start position:0% +switch and uh in a general binary tree +we will see that uh all these + + align:start position:0% +we will see that uh all these + + + align:start position:0% +we will see that uh all these +intermediate nodes over here they are + + align:start position:0% +intermediate nodes over here they are + + + align:start position:0% +intermediate nodes over here they are +all three times three switches so the + + align:start position:0% +all three times three switches so the + + + align:start position:0% +all three times three switches so the +the most the the approximately half of + + align:start position:0% +the most the the approximately half of + + + align:start position:0% +the most the the approximately half of +the the switches are actually three * + + align:start position:0% +the the switches are actually three * + + + align:start position:0% +the the switches are actually three * +three + + align:start position:0% +three + + + align:start position:0% +three +switches so that's a switch + + align:start position:0% + + + + align:start position:0% + +size um now you may say well uh why + + align:start position:0% +size um now you may say well uh why + + + align:start position:0% +size um now you may say well uh why +don't I use like a larger size switch + + align:start position:0% +don't I use like a larger size switch + + + align:start position:0% +don't I use like a larger size switch +that would help me a lot right if I + + align:start position:0% +that would help me a lot right if I + + + align:start position:0% +that would help me a lot right if I +could uh uh use say a four time 4 + + align:start position:0% +could uh uh use say a four time 4 + + + align:start position:0% +could uh uh use say a four time 4 +switch then I would be able to have more + + align:start position:0% +switch then I would be able to have more + + + align:start position:0% +switch then I would be able to have more +inputs coming in more outputs coming out + + align:start position:0% +inputs coming in more outputs coming out + + + align:start position:0% +inputs coming in more outputs coming out +and I can actually uh maybe use a tary + + align:start position:0% +and I can actually uh maybe use a tary + + + align:start position:0% +and I can actually uh maybe use a tary +tree rather than a binary tree in a + + align:start position:0% +tree rather than a binary tree in a + + + align:start position:0% +tree rather than a binary tree in a +binary tree every every node at the + + align:start position:0% +binary tree every every node at the + + + align:start position:0% +binary tree every every node at the +level has like two children right but we + + align:start position:0% +level has like two children right but we + + + align:start position:0% +level has like two children right but we +could design a tree that has at every + + align:start position:0% +could design a tree that has at every + + + align:start position:0% +could design a tree that has at every +level three children so then we can use + + align:start position:0% +level three children so then we can use + + + align:start position:0% +level three children so then we can use +four times four switches if you do that + + align:start position:0% +four times four switches if you do that + + + align:start position:0% +four times four switches if you do that +then the path from the LEF up to the + + align:start position:0% +then the path from the LEF up to the + + + align:start position:0% +then the path from the LEF up to the +root is getting shorter and the diameter + + align:start position:0% +root is getting shorter and the diameter + + + align:start position:0% +root is getting shorter and the diameter +gets smaller so if I increase sort of + + align:start position:0% +gets smaller so if I increase sort of + + + align:start position:0% +gets smaller so if I increase sort of +the switch size so rather than 3 * 3 we + + align:start position:0% +the switch size so rather than 3 * 3 we + + + align:start position:0% +the switch size so rather than 3 * 3 we +look at 4 * 4 or 5 * 5 6 * 6 and so on + + align:start position:0% +look at 4 * 4 or 5 * 5 6 * 6 and so on + + + align:start position:0% +look at 4 * 4 or 5 * 5 6 * 6 and so on +then the diameter will actually uh + + align:start position:0% +then the diameter will actually uh + + + align:start position:0% +then the diameter will actually uh +reduce so what about having a monster + + align:start position:0% +reduce so what about having a monster + + + align:start position:0% +reduce so what about having a monster +switch uh like I have just one switch + + align:start position:0% +switch uh like I have just one switch + + + align:start position:0% +switch uh like I have just one switch +and I have my input zero all the way up + + align:start position:0% +and I have my input zero all the way up + + + align:start position:0% +and I have my input zero all the way up +to input um n minus one and then I have + + align:start position:0% +to input um n minus one and then I have + + + align:start position:0% +to input um n minus one and then I have +my outputs on the other + + align:start position:0% + + + + align:start position:0% + +side well + + align:start position:0% +side well + + + align:start position:0% +side well +of course the switch size is n * n but + + align:start position:0% +of course the switch size is n * n but + + + align:start position:0% +of course the switch size is n * n but +the diameter is is is nothing right + + align:start position:0% +the diameter is is is nothing right + + + align:start position:0% +the diameter is is is nothing right +there's uh that you can immediately go + + align:start position:0% +there's uh that you can immediately go + + + align:start position:0% +there's uh that you can immediately go +from the diameter is reduced to one you + + align:start position:0% +from the diameter is reduced to one you + + + align:start position:0% +from the diameter is reduced to one you +can immediately go from an input to an + + align:start position:0% +can immediately go from an input to an + + + align:start position:0% +can immediately go from an input to an +output through the switch but this of + + align:start position:0% +output through the switch but this of + + + align:start position:0% +output through the switch but this of +course conceals the problem so what + + align:start position:0% +course conceals the problem so what + + + align:start position:0% +course conceals the problem so what +we're interested in is well we're + + align:start position:0% +we're interested in is well we're + + + align:start position:0% +we're interested in is well we're +actually really interested in in in in + + align:start position:0% +actually really interested in in in in + + + align:start position:0% +actually really interested in in in in +in in how to solve the problem of + + align:start position:0% +in in how to solve the problem of + + + align:start position:0% +in in how to solve the problem of +routing all these inputs to these + + align:start position:0% +routing all these inputs to these + + + align:start position:0% +routing all these inputs to these +outputs using uh smaller basic smaller + + align:start position:0% +outputs using uh smaller basic smaller + + + align:start position:0% +outputs using uh smaller basic smaller +switches of of size three times three or + + align:start position:0% +switches of of size three times three or + + + align:start position:0% +switches of of size three times three or +two time two what we really interested + + align:start position:0% +two time two what we really interested + + + align:start position:0% +two time two what we really interested +in is what is the internal structure in + + align:start position:0% +in is what is the internal structure in + + + align:start position:0% +in is what is the internal structure in +this monster switch I sort of have con + + align:start position:0% +this monster switch I sort of have con + + + align:start position:0% +this monster switch I sort of have con +concealed the problem by just saying oh + + align:start position:0% +concealed the problem by just saying oh + + + align:start position:0% +concealed the problem by just saying oh +I got a big switch but you know uh what + + align:start position:0% +I got a big switch but you know uh what + + + align:start position:0% +I got a big switch but you know uh what +we want to solve today is how do we do + + align:start position:0% +we want to solve today is how do we do + + + align:start position:0% +we want to solve today is how do we do +the routing uh in in this case within + + align:start position:0% +the routing uh in in this case within + + + align:start position:0% +the routing uh in in this case within +the monster switch so we want to use + + align:start position:0% +the monster switch so we want to use + + + align:start position:0% +the monster switch so we want to use +just small + + align:start position:0% +just small + + + align:start position:0% +just small +switch sizes and build up a network + + align:start position:0% +switch sizes and build up a network + + + align:start position:0% +switch sizes and build up a network +using these smaller ones like 3 * three + + align:start position:0% +using these smaller ones like 3 * three + + + align:start position:0% +using these smaller ones like 3 * three +switches or 2 * two + + align:start position:0% +switches or 2 * two + + + align:start position:0% +switches or 2 * two +switches um now + + align:start position:0% + + + + align:start position:0% + +um so um that brings us to yet another + + align:start position:0% +um so um that brings us to yet another + + + align:start position:0% +um so um that brings us to yet another +parameter because he would like to count + + align:start position:0% +parameter because he would like to count + + + align:start position:0% +parameter because he would like to count +the number of smaller switches that we + + align:start position:0% +the number of smaller switches that we + + + align:start position:0% +the number of smaller switches that we +use and that relates to the cost of the + + align:start position:0% +use and that relates to the cost of the + + + align:start position:0% +use and that relates to the cost of the +network uh the amount of Hardware that + + align:start position:0% +network uh the amount of Hardware that + + + align:start position:0% +network uh the amount of Hardware that +you need to put into it so in this + + align:start position:0% +you need to put into it so in this + + + align:start position:0% +you need to put into it so in this +example we have uh the switch + + align:start position:0% +example we have uh the switch + + + align:start position:0% +example we have uh the switch +um uh + + align:start position:0% + + + + align:start position:0% + +account well it's pretty simple right + + align:start position:0% +account well it's pretty simple right + + + align:start position:0% +account well it's pretty simple right +it's uh 1 2 3 4 five six seven we have + + align:start position:0% +it's uh 1 2 3 4 five six seven we have + + + align:start position:0% +it's uh 1 2 3 4 five six seven we have +seven + + align:start position:0% +seven + + + align:start position:0% +seven +switches and in general um yeah if we + + align:start position:0% +switches and in general um yeah if we + + + align:start position:0% +switches and in general um yeah if we +have uh n + + align:start position:0% +have uh n + + + align:start position:0% +have uh n +inputs so one two three four inputs then + + align:start position:0% +inputs so one two three four inputs then + + + align:start position:0% +inputs so one two three four inputs then +the number of switches that we use in + + align:start position:0% +the number of switches that we use in + + + align:start position:0% +the number of switches that we use in +the binary tree is 2 * the number of + + align:start position:0% +the binary tree is 2 * the number of + + + align:start position:0% +the binary tree is 2 * the number of +inputs minus one um so let's write that + + align:start position:0% +inputs minus one um so let's write that + + + align:start position:0% +inputs minus one um so let's write that +down so over here we would have 2 * n + + align:start position:0% +down so over here we would have 2 * n + + + align:start position:0% +down so over here we would have 2 * n +minus one which is the number of + + align:start position:0% +minus one which is the number of + + + align:start position:0% +minus one which is the number of +switches that you actually + + align:start position:0% +switches that you actually + + + align:start position:0% +switches that you actually +use um so how can you see that actually + + align:start position:0% +use um so how can you see that actually + + + align:start position:0% +use um so how can you see that actually +uh so in general we have uh 1 + 2 + 4 + + + align:start position:0% +uh so in general we have uh 1 + 2 + 4 + + + + align:start position:0% +uh so in general we have uh 1 + 2 + 4 + +8 and so on + + align:start position:0% +8 and so on + + + align:start position:0% +8 and so on +plus n n is a power of two according to + + align:start position:0% +plus n n is a power of two according to + + + align:start position:0% +plus n n is a power of two according to +our assumptions and if you add them all + + align:start position:0% +our assumptions and if you add them all + + + align:start position:0% +our assumptions and if you add them all +up uh I think you'll well you can check + + align:start position:0% +up uh I think you'll well you can check + + + align:start position:0% +up uh I think you'll well you can check +for yourself that this is actually equal + + align:start position:0% +for yourself that this is actually equal + + + align:start position:0% +for yourself that this is actually equal +to 2 * n minus + + align:start position:0% +to 2 * n minus + + + align:start position:0% +to 2 * n minus +one okay so now we have uh the switch + + align:start position:0% +one okay so now we have uh the switch + + + align:start position:0% +one okay so now we have uh the switch +here so so far this looks pretty good + + align:start position:0% +here so so far this looks pretty good + + + align:start position:0% +here so so far this looks pretty good +actually we use small switch sizes the + + align:start position:0% +actually we use small switch sizes the + + + align:start position:0% +actually we use small switch sizes the +number of switches is linear in N + + align:start position:0% +number of switches is linear in N + + + align:start position:0% +number of switches is linear in N +diameter is logarithmic in N so that + + align:start position:0% +diameter is logarithmic in N so that + + + align:start position:0% +diameter is logarithmic in N so that +sounds good so what about congestion do + + align:start position:0% +sounds good so what about congestion do + + + align:start position:0% +sounds good so what about congestion do +you have any idea what what's what's the + + align:start position:0% +you have any idea what what's what's the + + + align:start position:0% +you have any idea what what's what's the +problem with this graph what is the big + + align:start position:0% +problem with this graph what is the big + + + align:start position:0% +problem with this graph what is the big +big problem + + align:start position:0% +big problem + + + align:start position:0% +big problem +here what can happen in a very uh yeah + + align:start position:0% +here what can happen in a very uh yeah + + + align:start position:0% +here what can happen in a very uh yeah +sort of a worst case scenario where the + + align:start position:0% +sort of a worst case scenario where the + + + align:start position:0% +sort of a worst case scenario where the +packets get routed from the inputs to + + align:start position:0% +packets get routed from the inputs to + + + align:start position:0% +packets get routed from the inputs to +the outputs if they if they need to go + + align:start position:0% +the outputs if they if they need to go + + + align:start position:0% +the outputs if they if they need to go +to certain locations then then they may + + align:start position:0% +to certain locations then then they may + + + align:start position:0% +to certain locations then then they may +all may have to travel through the rout + + align:start position:0% +all may have to travel through the rout + + + align:start position:0% +all may have to travel through the rout +so you get congestion over here we don't + + align:start position:0% +so you get congestion over here we don't + + + align:start position:0% +so you get congestion over here we don't +like that so this rout is actually then + + align:start position:0% +like that so this rout is actually then + + + align:start position:0% +like that so this rout is actually then +overloaded actually you can already see + + align:start position:0% +overloaded actually you can already see + + + align:start position:0% +overloaded actually you can already see +that if say this + + align:start position:0% +that if say this + + + align:start position:0% +that if say this +this particular switch if this switch uh + + align:start position:0% +this particular switch if this switch uh + + + align:start position:0% +this particular switch if this switch uh +fails then actually we will have two + + align:start position:0% +fails then actually we will have two + + + align:start position:0% +fails then actually we will have two +disjoint trees that cannot even + + align:start position:0% +disjoint trees that cannot even + + + align:start position:0% +disjoint trees that cannot even +communicate to one another so uh this + + align:start position:0% +communicate to one another so uh this + + + align:start position:0% +communicate to one another so uh this +brings us to uh to to the idea of + + align:start position:0% +brings us to uh to to the idea of + + + align:start position:0% +brings us to uh to to the idea of +congestion + + align:start position:0% +congestion + + + align:start position:0% +congestion +and in order to Define it better you + + align:start position:0% +and in order to Define it better you + + + align:start position:0% +and in order to Define it better you +will need a few + + align:start position:0% + + + + align:start position:0% + +definitions + + align:start position:0% +definitions + + + align:start position:0% +definitions +so uh to start we will Define a + + align:start position:0% +so uh to start we will Define a + + + align:start position:0% +so uh to start we will Define a +permutation and we will use this + + align:start position:0% +permutation and we will use this + + + align:start position:0% +permutation and we will use this +to + + align:start position:0% +to + + + align:start position:0% +to +uh uh stipulate the requirement that we + + align:start position:0% +uh uh stipulate the requirement that we + + + align:start position:0% +uh uh stipulate the requirement that we +want on how inputs and outputs are + + align:start position:0% +want on how inputs and outputs are + + + align:start position:0% +want on how inputs and outputs are +related to one another which input needs + + align:start position:0% +related to one another which input needs + + + align:start position:0% +related to one another which input needs +to communicate to which output so + + align:start position:0% +to communicate to which output so + + + align:start position:0% +to communicate to which output so +permutation is a + + align:start position:0% + + + + align:start position:0% + +function function + + align:start position:0% +function function + + + align:start position:0% +function function +PI from the set 0 to n minus one one to + + align:start position:0% +PI from the set 0 to n minus one one to + + + align:start position:0% +PI from the set 0 to n minus one one to +the same + + align:start position:0% +the same + + + align:start position:0% +the same +set and + + align:start position:0% +set and + + + align:start position:0% +set and +um it is such + + align:start position:0% +um it is such + + + align:start position:0% +um it is such +that no two + + align:start position:0% +that no two + + + align:start position:0% +that no two +numbers um no no two numbers are mapped + + align:start position:0% +numbers um no no two numbers are mapped + + + align:start position:0% +numbers um no no two numbers are mapped +to more than + + align:start position:0% +to more than + + + align:start position:0% +to more than +ones so no two numbers are mapped + + align:start position:0% +ones so no two numbers are mapped + + + align:start position:0% +ones so no two numbers are mapped +to uh the same value + + align:start position:0% + + + + align:start position:0% + +so what we really want in to put it in + + align:start position:0% +so what we really want in to put it in + + + align:start position:0% +so what we really want in to put it in +mathematics right we want that Pi of I + + align:start position:0% +mathematics right we want that Pi of I + + + align:start position:0% +mathematics right we want that Pi of I +is only equal to Pi of J well if and + + align:start position:0% +is only equal to Pi of J well if and + + + align:start position:0% +is only equal to Pi of J well if and +only if uh I is equal to + + align:start position:0% +only if uh I is equal to + + + align:start position:0% +only if uh I is equal to +J so let's have uh an example uh to plug + + align:start position:0% +J so let's have uh an example uh to plug + + + align:start position:0% +J so let's have uh an example uh to plug +into that picture over there so a first + + align:start position:0% +into that picture over there so a first + + + align:start position:0% +into that picture over there so a first +example could be um + + align:start position:0% + + + + align:start position:0% + +Pi of I equals say n minus one minus I + + align:start position:0% +Pi of I equals say n minus one minus I + + + align:start position:0% +Pi of I equals say n minus one minus I +this is a proper + + align:start position:0% +this is a proper + + + align:start position:0% +this is a proper +permutation no two numbers m to the same + + align:start position:0% +permutation no two numbers m to the same + + + align:start position:0% +permutation no two numbers m to the same +value another one could be the identity + + align:start position:0% +value another one could be the identity + + + align:start position:0% +value another one could be the identity +permutation like you map I to the same I + + align:start position:0% +permutation like you map I to the same I + + + align:start position:0% +permutation like you map I to the same I +so that's another example now how do we + + align:start position:0% +so that's another example now how do we + + + align:start position:0% +so that's another example now how do we +use permutations to go towards the idea + + align:start position:0% +use permutations to go towards the idea + + + align:start position:0% +use permutations to go towards the idea +of congestion so permutation can be used + + align:start position:0% +of congestion so permutation can be used + + + align:start position:0% +of congestion so permutation can be used +to formulate the permutation routing + + align:start position:0% +to formulate the permutation routing + + + align:start position:0% +to formulate the permutation routing +problem + + align:start position:0% +problem + + + align:start position:0% +problem +and the permutation routing + + align:start position:0% +and the permutation routing + + + align:start position:0% +and the permutation routing +problem um is defined like + + align:start position:0% +problem um is defined like + + + align:start position:0% +problem um is defined like +this + + align:start position:0% + + + + align:start position:0% + +um it's defined as follows but we want + + align:start position:0% +um it's defined as follows but we want + + + align:start position:0% +um it's defined as follows but we want +is that for + + align:start position:0% +is that for + + + align:start position:0% +is that for +each I we want to + + align:start position:0% + + + + align:start position:0% + +direct the + + align:start position:0% + + + + align:start position:0% + +packet at input + + align:start position:0% +packet at input + + + align:start position:0% +packet at input +I to + + align:start position:0% +I to + + + align:start position:0% +I to +Output Pi of I so you want to do that + + align:start position:0% +Output Pi of I so you want to do that + + + align:start position:0% +Output Pi of I so you want to do that +for all I so let's have a look at uh at + + align:start position:0% +for all I so let's have a look at uh at + + + align:start position:0% +for all I so let's have a look at uh at +at this particular example where we look + + align:start position:0% +at this particular example where we look + + + align:start position:0% +at this particular example where we look +at identity + + align:start position:0% +at identity + + + align:start position:0% +at identity +permutation so if you do that we can + + align:start position:0% +permutation so if you do that we can + + + align:start position:0% +permutation so if you do that we can +easily route this right so I want to + + align:start position:0% +easily route this right so I want to + + + align:start position:0% +easily route this right so I want to +send a packet from input zero to Output + + align:start position:0% +send a packet from input zero to Output + + + align:start position:0% +send a packet from input zero to Output +zero so I can + + align:start position:0% +zero so I can + + + align:start position:0% +zero so I can +simply go into this direction I just go + + align:start position:0% +simply go into this direction I just go + + + align:start position:0% +simply go into this direction I just go +towards this switch and gets routed back + + align:start position:0% +towards this switch and gets routed back + + + align:start position:0% +towards this switch and gets routed back +to this one I + + align:start position:0% +to this one I + + + align:start position:0% +to this one I +can go like this and this one can go + + align:start position:0% +can go like this and this one can go + + + align:start position:0% +can go like this and this one can go +like this and this one goes like that + + align:start position:0% +like this and this one goes like that + + + align:start position:0% +like this and this one goes like that +now if you look at the other permutation + + align:start position:0% +now if you look at the other permutation + + + align:start position:0% +now if you look at the other permutation +the picture looks very + + align:start position:0% +the picture looks very + + + align:start position:0% +the picture looks very +different now we want to Route input + + align:start position:0% +different now we want to Route input + + + align:start position:0% +different now we want to Route input +zero to uh output three in order to do + + align:start position:0% +zero to uh output three in order to do + + + align:start position:0% +zero to uh output three in order to do +this I will actually need to go all the + + align:start position:0% +this I will actually need to go all the + + + align:start position:0% +this I will actually need to go all the +way through here + + align:start position:0% +way through here + + + align:start position:0% +way through here +and then all the way + + align:start position:0% + + + + align:start position:0% + +down to this particular + + align:start position:0% +down to this particular + + + align:start position:0% +down to this particular +output and now the picture gets into a + + align:start position:0% +output and now the picture gets into a + + + align:start position:0% +output and now the picture gets into a +big mess because uh for input one we + + align:start position:0% +big mess because uh for input one we + + + align:start position:0% +big mess because uh for input one we +have to go to Output uh three uh output + + align:start position:0% +have to go to Output uh three uh output + + + align:start position:0% +have to go to Output uh three uh output +two so for input one well we go all the + + align:start position:0% +two so for input one well we go all the + + + align:start position:0% +two so for input one well we go all the +way like this we again go through the + + align:start position:0% +way like this we again go through the + + + align:start position:0% +way like this we again go through the +root and then we go + + align:start position:0% +root and then we go + + + align:start position:0% +root and then we go +down uh to this particular output + + align:start position:0% +down uh to this particular output + + + align:start position:0% +down uh to this particular output +and as you can see for for for input two + + align:start position:0% +and as you can see for for for input two + + + align:start position:0% +and as you can see for for for input two +if well we need to connect to Output one + + align:start position:0% +if well we need to connect to Output one + + + align:start position:0% +if well we need to connect to Output one +so again we go all the way up and we go + + align:start position:0% +so again we go all the way up and we go + + + align:start position:0% +so again we go all the way up and we go +all the way down and for this one we + + align:start position:0% +all the way down and for this one we + + + align:start position:0% +all the way down and for this one we +will again go all the way up and all the + + align:start position:0% +will again go all the way up and all the + + + align:start position:0% +will again go all the way up and all the +way down to input zero so now you can + + align:start position:0% +way down to input zero so now you can + + + align:start position:0% +way down to input zero so now you can +see that this particular switch over + + align:start position:0% +see that this particular switch over + + + align:start position:0% +see that this particular switch over +here has to serve packets from all uh + + align:start position:0% +here has to serve packets from all uh + + + align:start position:0% +here has to serve packets from all uh +the inputs all the four packets have to + + align:start position:0% +the inputs all the four packets have to + + + align:start position:0% +the inputs all the four packets have to +travel through this particular note here + + align:start position:0% +travel through this particular note here + + + align:start position:0% +travel through this particular note here +so this leads us to uh the following + + align:start position:0% +so this leads us to uh the following + + + align:start position:0% +so this leads us to uh the following +definition of + + align:start position:0% +definition of + + + align:start position:0% +definition of +congestion so the + + align:start position:0% +congestion so the + + + align:start position:0% +congestion so the +congestion + + align:start position:0% + + + + align:start position:0% + +uh uh so oh before we continue let me + + align:start position:0% +uh uh so oh before we continue let me + + + align:start position:0% +uh uh so oh before we continue let me +first Define a path so for each I we + + align:start position:0% +first Define a path so for each I we + + + align:start position:0% +first Define a path so for each I we +direct a packet at input I to Output Pi + + align:start position:0% +direct a packet at input I to Output Pi + + + align:start position:0% +direct a packet at input I to Output Pi +of ey and the path that corresponds to + + align:start position:0% +of ey and the path that corresponds to + + + align:start position:0% +of ey and the path that corresponds to +this route is actually denoted by + + align:start position:0% +this route is actually denoted by + + + align:start position:0% +this route is actually denoted by +as as followed so the path + + align:start position:0% +as as followed so the path + + + align:start position:0% +as as followed so the path +uh + + align:start position:0% +uh + + + align:start position:0% +uh +taken is + + align:start position:0% + + + + align:start position:0% + +denoted by + + align:start position:0% +denoted by + + + align:start position:0% +denoted by +p i Pi + + align:start position:0% +p i Pi + + + align:start position:0% +p i Pi +I so now we can Define the congestion of + + align:start position:0% +I so now we can Define the congestion of + + + align:start position:0% +I so now we can Define the congestion of +a set of such paths so the con the + + align:start position:0% +a set of such paths so the con the + + + align:start position:0% +a set of such paths so the con the +congestion of the + + align:start position:0% +congestion of the + + + align:start position:0% +congestion of the +path corresponding to + + align:start position:0% +path corresponding to + + + align:start position:0% +path corresponding to +uh P0 to p pi0 and so on and we go all + + align:start position:0% +uh P0 to p pi0 and so on and we go all + + + align:start position:0% +uh P0 to p pi0 and so on and we go all +the way up to the N minus one input that + + align:start position:0% +the way up to the N minus one input that + + + align:start position:0% +the way up to the N minus one input that +needs to be mapped to Pi of n minus one + + align:start position:0% +needs to be mapped to Pi of n minus one + + + align:start position:0% +needs to be mapped to Pi of n minus one +so the congestion is now + + align:start position:0% +so the congestion is now + + + align:start position:0% +so the congestion is now +defined as the + + align:start position:0% + + + + align:start position:0% + +number to the largest + + align:start position:0% + + + + align:start position:0% + +number of paths + + align:start position:0% + + + + align:start position:0% + +that pass + + align:start position:0% + + + + align:start position:0% + +through a single + + align:start position:0% +through a single + + + align:start position:0% +through a single +switch so in our example + + align:start position:0% +switch so in our example + + + align:start position:0% +switch so in our example +we saw that in the case of the blue + + align:start position:0% +we saw that in the case of the blue + + + align:start position:0% +we saw that in the case of the blue +arrows here which for the identity + + align:start position:0% +arrows here which for the identity + + + align:start position:0% +arrows here which for the identity +permutation well uh this switch only + + align:start position:0% +permutation well uh this switch only + + + align:start position:0% +permutation well uh this switch only +needs to transmit one packet and and all + + align:start position:0% +needs to transmit one packet and and all + + + align:start position:0% +needs to transmit one packet and and all +those actually zero packets so actually + + align:start position:0% +those actually zero packets so actually + + + align:start position:0% +those actually zero packets so actually +the congestion here is + + align:start position:0% + + + + align:start position:0% + +equal to one and for this particular + + align:start position:0% +equal to one and for this particular + + + align:start position:0% +equal to one and for this particular +permutation well we had to direct all + + align:start position:0% +permutation well we had to direct all + + + align:start position:0% +permutation well we had to direct all +the packets through the root and it's + + align:start position:0% +the packets through the root and it's + + + align:start position:0% +the packets through the root and it's +the worst the most accessed switch and + + align:start position:0% +the worst the most accessed switch and + + + align:start position:0% +the worst the most accessed switch and +that switch has congestion four right + + align:start position:0% +that switch has congestion four right + + + align:start position:0% +that switch has congestion four right +so the congestion of over + + align:start position:0% +so the congestion of over + + + align:start position:0% +so the congestion of over +here is equal to + + align:start position:0% +here is equal to + + + align:start position:0% +here is equal to +four now this does not look so good + + align:start position:0% +four now this does not look so good + + + align:start position:0% +four now this does not look so good +because uh for a binary tree we always + + align:start position:0% +because uh for a binary tree we always + + + align:start position:0% +because uh for a binary tree we always +have this vulnerable root that is right + + align:start position:0% +have this vulnerable root that is right + + + align:start position:0% +have this vulnerable root that is right +here in the center + + align:start position:0% +here in the center + + + align:start position:0% +here in the center +connecting the left side to the right + + align:start position:0% +connecting the left side to the right + + + align:start position:0% +connecting the left side to the right +side so I can always find a permutation + + align:start position:0% +side so I can always find a permutation + + + align:start position:0% +side so I can always find a permutation +actually this permutation over here that + + align:start position:0% +actually this permutation over here that + + + align:start position:0% +actually this permutation over here that +leads to this worst case + + align:start position:0% +leads to this worst case + + + align:start position:0% +leads to this worst case +congestion so what we're interested in + + align:start position:0% +congestion so what we're interested in + + + align:start position:0% +congestion so what we're interested in +is the maximum congestion which is sort + + align:start position:0% +is the maximum congestion which is sort + + + align:start position:0% +is the maximum congestion which is sort +of the worst case + + align:start position:0% +of the worst case + + + align:start position:0% +of the worst case +scenario and you'll Define + + align:start position:0% + + + + align:start position:0% + +it as + + align:start position:0% +it as + + + align:start position:0% +it as +follows the maximum congestion is + + align:start position:0% +follows the maximum congestion is + + + align:start position:0% +follows the maximum congestion is +actually equal to the + + align:start position:0% +actually equal to the + + + align:start position:0% +actually equal to the +maximum over all permutations Pi so this + + align:start position:0% +maximum over all permutations Pi so this + + + align:start position:0% +maximum over all permutations Pi so this +is kind of the worst case routing + + align:start position:0% +is kind of the worst case routing + + + align:start position:0% +is kind of the worst case routing +problem that I can imagine and that may + + align:start position:0% +problem that I can imagine and that may + + + align:start position:0% +problem that I can imagine and that may +occur in practice so in the worst + + align:start position:0% +occur in practice so in the worst + + + align:start position:0% +occur in practice so in the worst +case how can I solve it the best test so + + align:start position:0% +case how can I solve it the best test so + + + align:start position:0% +case how can I solve it the best test so +I want to find the + + align:start position:0% +I want to find the + + + align:start position:0% +I want to find the +minimum uh of the + + align:start position:0% +minimum uh of the + + + align:start position:0% +minimum uh of the +congestion I want to find the minimum + + align:start position:0% +congestion I want to find the minimum + + + align:start position:0% +congestion I want to find the minimum +congestion of a + + align:start position:0% + + + + align:start position:0% + +pass over + + align:start position:0% +pass over + + + align:start position:0% +pass over +here and uh the minimum is over these + + align:start position:0% +here and uh the minimum is over these + + + align:start position:0% +here and uh the minimum is over these +types of paths so actually this is uh + + align:start position:0% +types of paths so actually this is uh + + + align:start position:0% +types of paths so actually this is uh +our solution to this routing problem we + + align:start position:0% +our solution to this routing problem we + + + align:start position:0% +our solution to this routing problem we +want to find the best kind of solution + + align:start position:0% +want to find the best kind of solution + + + align:start position:0% +want to find the best kind of solution +for this worst case + + align:start position:0% +for this worst case + + + align:start position:0% +for this worst case +scenario + + align:start position:0% +scenario + + + align:start position:0% +scenario +so + + align:start position:0% +so + + + align:start position:0% +so +uh the minimum over all solutions for + + align:start position:0% +uh the minimum over all solutions for + + + align:start position:0% +uh the minimum over all solutions for +these + + align:start position:0% + + + + align:start position:0% + +paths so uh + + align:start position:0% +paths so uh + + + align:start position:0% +paths so uh +well for for this particular tree + + align:start position:0% +well for for this particular tree + + + align:start position:0% +well for for this particular tree +structure this permutation is really the + + align:start position:0% +structure this permutation is really the + + + align:start position:0% +structure this permutation is really the +worst case scenario that you can have + + align:start position:0% +worst case scenario that you can have + + + align:start position:0% +worst case scenario that you can have +because every packet needs to be routed + + align:start position:0% +because every packet needs to be routed + + + align:start position:0% +because every packet needs to be routed +through the center over here and it + + align:start position:0% +through the center over here and it + + + align:start position:0% +through the center over here and it +means that our maximum congestion for an + + align:start position:0% +means that our maximum congestion for an + + + align:start position:0% +means that our maximum congestion for an +arbitrary tree is actually equal to + + align:start position:0% + + + + align:start position:0% + +n + + align:start position:0% +n + + + align:start position:0% +n +so now that that that looks really bad + + align:start position:0% +so now that that that looks really bad + + + align:start position:0% +so now that that that looks really bad +actually so we don't like this uh uh at + + align:start position:0% +actually so we don't like this uh uh at + + + align:start position:0% +actually so we don't like this uh uh at +all so let's find out whether we can do + + align:start position:0% +all so let's find out whether we can do + + + align:start position:0% +all so let's find out whether we can do +a little bit better and uh we're going + + align:start position:0% +a little bit better and uh we're going + + + align:start position:0% +a little bit better and uh we're going +to to look at the two-dimensional array + + align:start position:0% +to to look at the two-dimensional array + + + align:start position:0% +to to look at the two-dimensional array +and see uh what that would lead up + + align:start position:0% +and see uh what that would lead up + + + align:start position:0% +and see uh what that would lead up +to + + align:start position:0% +to + + + align:start position:0% +to +and its structure is as + + align:start position:0% + + + + align:start position:0% + +follows um we essentially have inputs on + + align:start position:0% +follows um we essentially have inputs on + + + align:start position:0% +follows um we essentially have inputs on +uh the left and uh the outputs are on + + align:start position:0% +uh the left and uh the outputs are on + + + align:start position:0% +uh the left and uh the outputs are on +the bottom and they are in a grid + + align:start position:0% +the bottom and they are in a grid + + + align:start position:0% +the bottom and they are in a grid +structure so we have input zero input + + align:start position:0% +structure so we have input zero input + + + align:start position:0% +structure so we have input zero input +one input two + + align:start position:0% +one input two + + + align:start position:0% +one input two +input three they all connect to their + + align:start position:0% + + + + align:start position:0% + +terminals we have + + align:start position:0% + + + + align:start position:0% + +switches um four of those and they are + + align:start position:0% +switches um four of those and they are + + + align:start position:0% +switches um four of those and they are +all connected in this + + align:start position:0% + + + + align:start position:0% + +grid and at the very bottom we will have + + align:start position:0% +grid and at the very bottom we will have + + + align:start position:0% +grid and at the very bottom we will have +the + + align:start position:0% +the + + + align:start position:0% +the +outputs the output terminals + + align:start position:0% + + + + align:start position:0% + +so this is output uh uh zero and here we + + align:start position:0% +so this is output uh uh zero and here we + + + align:start position:0% +so this is output uh uh zero and here we +will have output one output two and + + align:start position:0% +will have output one output two and + + + align:start position:0% +will have output one output two and +output + + align:start position:0% + + + + align:start position:0% + +three so I notice that my circles start + + align:start position:0% +three so I notice that my circles start + + + align:start position:0% +three so I notice that my circles start +to resemble my squares + + align:start position:0% +to resemble my squares + + + align:start position:0% +to resemble my squares +but these are all the switches right + + align:start position:0% +but these are all the switches right + + + align:start position:0% +but these are all the switches right +here in the center so how does this work + + align:start position:0% +here in the center so how does this work + + + align:start position:0% +here in the center so how does this work +well + + align:start position:0% +well + + + align:start position:0% +well +um well do we have a better better + + align:start position:0% +um well do we have a better better + + + align:start position:0% +um well do we have a better better +parameter so let's look at it together + + align:start position:0% +parameter so let's look at it together + + + align:start position:0% +parameter so let's look at it together +so we need to first of all figure out + + align:start position:0% +so we need to first of all figure out + + + align:start position:0% +so we need to first of all figure out +what the diameter is so what's the + + align:start position:0% +what the diameter is so what's the + + + align:start position:0% +what the diameter is so what's the +diameter of this particular uh + + align:start position:0% +diameter of this particular uh + + + align:start position:0% +diameter of this particular uh +Network so what's the F what's the + + align:start position:0% +Network so what's the F what's the + + + align:start position:0% +Network so what's the F what's the +shortest path between the furthest uh + + align:start position:0% +shortest path between the furthest uh + + + align:start position:0% +shortest path between the furthest uh +input and + + align:start position:0% +input and + + + align:start position:0% +input and +output so well if you look at that we + + align:start position:0% +output so well if you look at that we + + + align:start position:0% +output so well if you look at that we +can see that if I go from all the way + + align:start position:0% +can see that if I go from all the way + + + align:start position:0% +can see that if I go from all the way +from here and I go all the way down to + + align:start position:0% +from here and I go all the way down to + + + align:start position:0% +from here and I go all the way down to +this corner that looks like the largest + + align:start position:0% +this corner that looks like the largest + + + align:start position:0% +this corner that looks like the largest +uh path and I need to cross all these uh + + align:start position:0% +uh path and I need to cross all these uh + + + align:start position:0% +uh path and I need to cross all these uh +wires and in general for any + + align:start position:0% +wires and in general for any + + + align:start position:0% +wires and in general for any +n we will have that the diameter is 2 * + + align:start position:0% +n we will have that the diameter is 2 * + + + align:start position:0% +n we will have that the diameter is 2 * +n now what about the switch + + align:start position:0% +n now what about the switch + + + align:start position:0% +n now what about the switch +size it looks a little bit smaller right + + align:start position:0% +size it looks a little bit smaller right + + + align:start position:0% +size it looks a little bit smaller right +because over here we had three inputs + + align:start position:0% +because over here we had three inputs + + + align:start position:0% +because over here we had three inputs +coming in and three outputs coming out + + align:start position:0% +coming in and three outputs coming out + + + align:start position:0% +coming in and three outputs coming out +but over here we see that every single + + align:start position:0% +but over here we see that every single + + + align:start position:0% +but over here we see that every single +switch has only two inputs and two + + align:start position:0% +switch has only two inputs and two + + + align:start position:0% +switch has only two inputs and two +outputs so that makes the size uh 2 * + + align:start position:0% +outputs so that makes the size uh 2 * + + + align:start position:0% +outputs so that makes the size uh 2 * +two uh now the number of switches is + + align:start position:0% +two uh now the number of switches is + + + align:start position:0% +two uh now the number of switches is +pretty bad right because we have n + + align:start position:0% +pretty bad right because we have n + + + align:start position:0% +pretty bad right because we have n +Square switches so that's that's really + + align:start position:0% +Square switches so that's that's really + + + align:start position:0% +Square switches so that's that's really +horrible that's that that's a lot we + + align:start position:0% +horrible that's that that's a lot we + + + align:start position:0% +horrible that's that that's a lot we +would like to do much better and what + + align:start position:0% +would like to do much better and what + + + align:start position:0% +would like to do much better and what +about the congestion do you have any + + align:start position:0% +about the congestion do you have any + + + align:start position:0% +about the congestion do you have any +idea what what the congestion could be + + align:start position:0% +idea what what the congestion could be + + + align:start position:0% +idea what what the congestion could be +in this particular case we will prove a + + align:start position:0% +in this particular case we will prove a + + + align:start position:0% +in this particular case we will prove a +theorem on + + align:start position:0% +theorem on + + + align:start position:0% +theorem on +that so is there a way to uh map for any + + align:start position:0% +that so is there a way to uh map for any + + + align:start position:0% +that so is there a way to uh map for any +permutation is there a way to map uh the + + align:start position:0% +permutation is there a way to map uh the + + + align:start position:0% +permutation is there a way to map uh the +inputs to Route the inputs to the + + align:start position:0% +inputs to Route the inputs to the + + + align:start position:0% +inputs to Route the inputs to the +outputs in such a way that the switches + + align:start position:0% +outputs in such a way that the switches + + + align:start position:0% +outputs in such a way that the switches +get almost not congested so in the + + align:start position:0% +get almost not congested so in the + + + align:start position:0% +get almost not congested so in the +binary tree we had a congestion of of of + + align:start position:0% +binary tree we had a congestion of of of + + + align:start position:0% +binary tree we had a congestion of of of +of n which is linear in the + + align:start position:0% +of n which is linear in the + + + align:start position:0% +of n which is linear in the +switches but uh over here we can do much + + align:start position:0% +switches but uh over here we can do much + + + align:start position:0% +switches but uh over here we can do much +better we will show + + align:start position:0% + + + + align:start position:0% + +that uh the + + align:start position:0% + + + + align:start position:0% + +congestion uh of + + align:start position:0% +congestion uh of + + + align:start position:0% +congestion uh of +an N + + align:start position:0% +an N + + + align:start position:0% +an N +input + + align:start position:0% +input + + + align:start position:0% +input +array is actually equal to + + align:start position:0% +array is actually equal to + + + align:start position:0% +array is actually equal to +two so that's great so so I I'll prove + + align:start position:0% +two so that's great so so I I'll prove + + + align:start position:0% +two so that's great so so I I'll prove +it in a moment but uh that looks really + + align:start position:0% +it in a moment but uh that looks really + + + align:start position:0% +it in a moment but uh that looks really +fantastic and uh so it's way better than + + align:start position:0% +fantastic and uh so it's way better than + + + align:start position:0% +fantastic and uh so it's way better than +the binary Tre now this is really not so + + align:start position:0% +the binary Tre now this is really not so + + + align:start position:0% +the binary Tre now this is really not so +good and this is also much larger but + + align:start position:0% +good and this is also much larger but + + + align:start position:0% +good and this is also much larger but +but still + + align:start position:0% +but still + + + align:start position:0% +but still +um we will start to think next after we + + align:start position:0% +um we will start to think next after we + + + align:start position:0% +um we will start to think next after we +show this particular property uh how to + + align:start position:0% +show this particular property uh how to + + + align:start position:0% +show this particular property uh how to +combine these two and see how we can + + align:start position:0% +combine these two and see how we can + + + align:start position:0% +combine these two and see how we can +come up with another Network that maybe + + align:start position:0% +come up with another Network that maybe + + + align:start position:0% +come up with another Network that maybe +combine that that's able to combine in + + align:start position:0% +combine that that's able to combine in + + + align:start position:0% +combine that that's able to combine in +some ways these two properties and maybe + + align:start position:0% +some ways these two properties and maybe + + + align:start position:0% +some ways these two properties and maybe +we can find a good solution that way + + align:start position:0% +we can find a good solution that way + + + align:start position:0% +we can find a good solution that way +turns out we will not immediately be + + align:start position:0% +turns out we will not immediately be + + + align:start position:0% +turns out we will not immediately be +able to do that and we will need to make + + align:start position:0% +able to do that and we will need to make + + + align:start position:0% +able to do that and we will need to make +another step and come to the last uh + + align:start position:0% +another step and come to the last uh + + + align:start position:0% +another step and come to the last uh +Network that really has good parameters + + align:start position:0% +Network that really has good parameters + + + align:start position:0% +Network that really has good parameters +so what about the + + align:start position:0% +so what about the + + + align:start position:0% +so what about the +theorem so if we prove + + align:start position:0% +theorem so if we prove + + + align:start position:0% +theorem so if we prove +this well how do we start you just start + + align:start position:0% +this well how do we start you just start + + + align:start position:0% +this well how do we start you just start +with any permutation if I want to prove + + align:start position:0% +with any permutation if I want to prove + + + align:start position:0% +with any permutation if I want to prove +something about the congestion it's + + align:start position:0% +something about the congestion it's + + + align:start position:0% +something about the congestion it's +defined as the maximum over all + + align:start position:0% +defined as the maximum over all + + + align:start position:0% +defined as the maximum over all +permutations well let's let's take one + + align:start position:0% +permutations well let's let's take one + + + align:start position:0% +permutations well let's let's take one +of them and see what we can prove + + align:start position:0% + + + + align:start position:0% + +so let's + + align:start position:0% +so let's + + + align:start position:0% +so let's +um + + align:start position:0% + + + + align:start position:0% + +uh so let's us Define uh the path for + + align:start position:0% +uh so let's us Define uh the path for + + + align:start position:0% +uh so let's us Define uh the path for +this permutation follow so what we + + align:start position:0% +this permutation follow so what we + + + align:start position:0% +this permutation follow so what we +really want to do is we take any + + align:start position:0% +really want to do is we take any + + + align:start position:0% +really want to do is we take any +permutation and we want to find a really + + align:start position:0% +permutation and we want to find a really + + + align:start position:0% +permutation and we want to find a really +good solution for the routing if that if + + align:start position:0% +good solution for the routing if that if + + + align:start position:0% +good solution for the routing if that if +that gives us a very low congestion + + align:start position:0% +that gives us a very low congestion + + + align:start position:0% +that gives us a very low congestion +we're very + + align:start position:0% +we're very + + + align:start position:0% +we're very +happy so the way to do this is well + + align:start position:0% +happy so the way to do this is well + + + align:start position:0% +happy so the way to do this is well +maybe you have an idea already um so how + + align:start position:0% +maybe you have an idea already um so how + + + align:start position:0% +maybe you have an idea already um so how +would I route this so I want to connect + + align:start position:0% +would I route this so I want to connect + + + align:start position:0% +would I route this so I want to connect +an input uh I say one to Output two for + + align:start position:0% +an input uh I say one to Output two for + + + align:start position:0% +an input uh I say one to Output two for +example um how can I do this any + + align:start position:0% +example um how can I do this any + + + align:start position:0% +example um how can I do this any +suggestions so of course I could go any + + align:start position:0% +suggestions so of course I could go any + + + align:start position:0% +suggestions so of course I could go any +path but somehow I want to have some + + align:start position:0% +path but somehow I want to have some + + + align:start position:0% +path but somehow I want to have some +uniform structure that hopefully helps + + align:start position:0% +uniform structure that hopefully helps + + + align:start position:0% +uniform structure that hopefully helps +me to prove that the congestion in every + + align:start position:0% +me to prove that the congestion in every + + + align:start position:0% +me to prove that the congestion in every +switch is very small so how could I + + align:start position:0% +switch is very small so how could I + + + align:start position:0% +switch is very small so how could I +think about it + + align:start position:0% +think about it + + + align:start position:0% +think about it +um well um + + align:start position:0% +um well um + + + align:start position:0% +um well um +if I make sure that uh say a packet that + + align:start position:0% +if I make sure that uh say a packet that + + + align:start position:0% +if I make sure that uh say a packet that +goes from one to Output two is only + + align:start position:0% +goes from one to Output two is only + + + align:start position:0% +goes from one to Output two is only +going to be participating in the wires + + align:start position:0% +going to be participating in the wires + + + align:start position:0% +going to be participating in the wires +of the uh + + align:start position:0% +of the uh + + + align:start position:0% +of the uh +iow and the pi column then I know that + + align:start position:0% +iow and the pi column then I know that + + + align:start position:0% +iow and the pi column then I know that +uh every wire will only get uh traveled + + align:start position:0% +uh every wire will only get uh traveled + + + align:start position:0% +uh every wire will only get uh traveled +over twice it it could by by a packet it + + align:start position:0% +over twice it it could by by a packet it + + + align:start position:0% +over twice it it could by by a packet it +could either be a packet that goes into + + align:start position:0% +could either be a packet that goes into + + + align:start position:0% +could either be a packet that goes into +this direction or so so a switch will be + + align:start position:0% +this direction or so so a switch will be + + + align:start position:0% +this direction or so so a switch will be +accessed at most twice a switch can + + align:start position:0% +accessed at most twice a switch can + + + align:start position:0% +accessed at most twice a switch can +either receive a packet from this + + align:start position:0% +either receive a packet from this + + + align:start position:0% +either receive a packet from this +direction or receive a packet from uh + + align:start position:0% +direction or receive a packet from uh + + + align:start position:0% +direction or receive a packet from uh +from from the um from the upper + + align:start position:0% +from from the um from the upper + + + align:start position:0% +from from the um from the upper +part so that would be a really good idea + + align:start position:0% +part so that would be a really good idea + + + align:start position:0% +part so that would be a really good idea +so let's uh Define that + + align:start position:0% +so let's uh Define that + + + align:start position:0% +so let's uh Define that +so we say that in our solution we will + + align:start position:0% +so we say that in our solution we will + + + align:start position:0% +so we say that in our solution we will +Design such that the path from input I + + align:start position:0% +Design such that the path from input I + + + align:start position:0% +Design such that the path from input I +is actually going to be right + + align:start position:0% + + + + align:start position:0% + +word uh two + + align:start position:0% + + + + align:start position:0% + +column Pi I and then downward to the + + align:start position:0% +column Pi I and then downward to the + + + align:start position:0% +column Pi I and then downward to the +output so + + align:start position:0% +output so + + + align:start position:0% +output so +downward + + align:start position:0% +downward + + + align:start position:0% +downward +to + + align:start position:0% +to + + + align:start position:0% +to +um output by I so this + + align:start position:0% +um output by I so this + + + align:start position:0% +um output by I so this +is a really uh good solution to the + + align:start position:0% +is a really uh good solution to the + + + align:start position:0% +is a really uh good solution to the +router problem because now we can uh + + align:start position:0% +router problem because now we can uh + + + align:start position:0% +router problem because now we can uh +continue our proof as follows we just + + align:start position:0% +continue our proof as follows we just + + + align:start position:0% +continue our proof as follows we just +say + + align:start position:0% +say + + + align:start position:0% +say +well um if you look at the + + align:start position:0% +well um if you look at the + + + align:start position:0% +well um if you look at the +switch in row I and a column Pi + + align:start position:0% + + + + align:start position:0% + +I well this one actually transmits at + + align:start position:0% +I well this one actually transmits at + + + align:start position:0% +I well this one actually transmits at +most two packets + + align:start position:0% + + + + align:start position:0% + +because a packet can only come from um + + align:start position:0% +because a packet can only come from um + + + align:start position:0% +because a packet can only come from um +uh from the um left or it can go from + + align:start position:0% +uh from the um left or it can go from + + + align:start position:0% +uh from the um left or it can go from +the top so either one of the two uh at + + align:start position:0% +the top so either one of the two uh at + + + align:start position:0% +the top so either one of the two uh at +most those two packets will go through + + align:start position:0% +most those two packets will go through + + + align:start position:0% +most those two packets will go through +the switch so this shows that we have uh + + align:start position:0% +the switch so this shows that we have uh + + + align:start position:0% +the switch so this shows that we have uh +a congestion of at most two for any + + align:start position:0% +a congestion of at most two for any + + + align:start position:0% +a congestion of at most two for any +permutation and in order to prove + + align:start position:0% +permutation and in order to prove + + + align:start position:0% +permutation and in order to prove +equality because that's really what the + + align:start position:0% +equality because that's really what the + + + align:start position:0% +equality because that's really what the +theorem says we also have to show that + + align:start position:0% +theorem says we also have to show that + + + align:start position:0% +theorem says we also have to show that +there exists a permutation that achieves + + align:start position:0% +there exists a permutation that achieves + + + align:start position:0% +there exists a permutation that achieves +uh a congestion of two and that is + + align:start position:0% +uh a congestion of two and that is + + + align:start position:0% +uh a congestion of two and that is +pretty straightforward we can for + + align:start position:0% +pretty straightforward we can for + + + align:start position:0% +pretty straightforward we can for +example use a specific uh permutation + + align:start position:0% +example use a specific uh permutation + + + align:start position:0% +example use a specific uh permutation +that Maps 0 to zero and Maps n minus1 to + + align:start position:0% +that Maps 0 to zero and Maps n minus1 to + + + align:start position:0% +that Maps 0 to zero and Maps n minus1 to +n minus one well for this particular + + align:start position:0% +n minus one well for this particular + + + align:start position:0% +n minus one well for this particular +permutation when we look at uh the + + align:start position:0% +permutation when we look at uh the + + + align:start position:0% +permutation when we look at uh the +picture over here we say said that we + + align:start position:0% +picture over here we say said that we + + + align:start position:0% +picture over here we say said that we +see that input zero needs to go to + + align:start position:0% +see that input zero needs to go to + + + align:start position:0% +see that input zero needs to go to +Output zero um we also see that this uh + + align:start position:0% +Output zero um we also see that this uh + + + align:start position:0% +Output zero um we also see that this uh +lowest um input input three needs to + + align:start position:0% +lowest um input input three needs to + + + align:start position:0% +lowest um input input three needs to +travel all the way up to here but it's + + align:start position:0% +travel all the way up to here but it's + + + align:start position:0% +travel all the way up to here but it's +clear that the packet that needs to go + + align:start position:0% +clear that the packet that needs to go + + + align:start position:0% +clear that the packet that needs to go +over here needs to travel through that + + align:start position:0% +over here needs to travel through that + + + align:start position:0% +over here needs to travel through that +switch in the lower um um left bottom + + align:start position:0% +switch in the lower um um left bottom + + + align:start position:0% +switch in the lower um um left bottom +corner and uh the input three also needs + + align:start position:0% +corner and uh the input three also needs + + + align:start position:0% +corner and uh the input three also needs +to travel through that so here we + + align:start position:0% +to travel through that so here we + + + align:start position:0% +to travel through that so here we +clearly see that we have a congestion of + + align:start position:0% +clearly see that we have a congestion of + + + align:start position:0% +clearly see that we have a congestion of +two so now the proof is complete because + + align:start position:0% +two so now the proof is complete because + + + align:start position:0% +two so now the proof is complete because +we have shown uh this upper bound so for + + align:start position:0% +we have shown uh this upper bound so for + + + align:start position:0% +we have shown uh this upper bound so for +any permutation the congestion is at + + align:start position:0% +any permutation the congestion is at + + + align:start position:0% +any permutation the congestion is at +most two and we uh see that um this + + align:start position:0% +most two and we uh see that um this + + + align:start position:0% +most two and we uh see that um this +specific permutation achieves uh this + + align:start position:0% +specific permutation achieves uh this + + + align:start position:0% +specific permutation achieves uh this +congestion so this is the end of this + + align:start position:0% +congestion so this is the end of this + + + align:start position:0% +congestion so this is the end of this +proof okay so that's great so now what + + align:start position:0% +proof okay so that's great so now what + + + align:start position:0% +proof okay so that's great so now what +we like to do is we like to combine + + align:start position:0% +we like to do is we like to combine + + + align:start position:0% +we like to do is we like to combine +these two uh networks and see what we + + align:start position:0% +these two uh networks and see what we + + + align:start position:0% +these two uh networks and see what we +can learn from both so now we'll be + + align:start position:0% +can learn from both so now we'll be + + + align:start position:0% +can learn from both so now we'll be +taking out a lot of uh chalk over + + align:start position:0% +taking out a lot of uh chalk over + + + align:start position:0% +taking out a lot of uh chalk over +here so the idea is to construct a + + align:start position:0% +here so the idea is to construct a + + + align:start position:0% +here so the idea is to construct a +butterfly + + align:start position:0% +butterfly + + + align:start position:0% +butterfly +Network and uh I will draw it in such a + + align:start position:0% +Network and uh I will draw it in such a + + + align:start position:0% +Network and uh I will draw it in such a +way that you can see the recursive + + align:start position:0% + + + + align:start position:0% + +structure the idea is to um + + align:start position:0% +structure the idea is to um + + + align:start position:0% +structure the idea is to um +to + + align:start position:0% + + + + align:start position:0% + +uh to do the following thing so let me + + align:start position:0% +uh to do the following thing so let me + + + align:start position:0% +uh to do the following thing so let me +see how I can do this the best um so I + + align:start position:0% +see how I can do this the best um so I + + + align:start position:0% +see how I can do this the best um so I +just do the the the Top Line first and I + + align:start position:0% +just do the the the Top Line first and I + + + align:start position:0% +just do the the the Top Line first and I +have the spacing so we have input zero a + + align:start position:0% +have the spacing so we have input zero a + + + align:start position:0% +have the spacing so we have input zero a +terminal we have a switch we have a + + align:start position:0% +terminal we have a switch we have a + + + align:start position:0% +terminal we have a switch we have a +switch we have a switch and another one + + align:start position:0% +switch we have a switch and another one + + + align:start position:0% +switch we have a switch and another one +and here we have the + + align:start position:0% +and here we have the + + + align:start position:0% +and here we have the +output zero so the whole idea + + align:start position:0% +output zero so the whole idea + + + align:start position:0% +output zero so the whole idea +is that I'm going to combine every two + + align:start position:0% +is that I'm going to combine every two + + + align:start position:0% +is that I'm going to combine every two +outputs uh by using a small butterfly + + align:start position:0% +outputs uh by using a small butterfly + + + align:start position:0% +outputs uh by using a small butterfly +structure so we have + + align:start position:0% +structure so we have + + + align:start position:0% +structure so we have +two output + + align:start position:0% + + + + align:start position:0% + +three output + + align:start position:0% + + + + align:start position:0% + +four actually I need a look a little bit + + align:start position:0% +four actually I need a look a little bit + + + align:start position:0% +four actually I need a look a little bit +more + + align:start position:0% + + + + align:start position:0% + +space do it once + + align:start position:0% + + + + align:start position:0% + +more I put + + align:start position:0% +more I put + + + align:start position:0% +more I put +one + + align:start position:0% +one + + + align:start position:0% +one +two + + align:start position:0% +two + + + align:start position:0% +two + + align:start position:0% + + + align:start position:0% +four five six and the last one seven + + align:start position:0% +four five six and the last one seven + + + align:start position:0% +four five six and the last one seven +okay this is going to be pretty tight on + + align:start position:0% +okay this is going to be pretty tight on + + + align:start position:0% +okay this is going to be pretty tight on +the board so what's happening is this so + + align:start position:0% +the board so what's happening is this so + + + align:start position:0% +the board so what's happening is this so +these are all connected of course to + + align:start position:0% +these are all connected of course to + + + align:start position:0% +these are all connected of course to +switches the switches output + + align:start position:0% + + + + align:start position:0% + +those and uh the idea is that we create + + align:start position:0% +those and uh the idea is that we create + + + align:start position:0% +those and uh the idea is that we create +the following structure this switch can + + align:start position:0% +the following structure this switch can + + + align:start position:0% +the following structure this switch can +either forward it over here or can cross + + align:start position:0% +either forward it over here or can cross + + + align:start position:0% +either forward it over here or can cross +it over to this particular line and this + + align:start position:0% +it over to this particular line and this + + + align:start position:0% +it over to this particular line and this +switch can either forward it or cross it + + align:start position:0% +switch can either forward it or cross it + + + align:start position:0% +switch can either forward it or cross it +over to this line so this is a very + + align:start position:0% +over to this line so this is a very + + + align:start position:0% +over to this line so this is a very +small butterfly structure where we have + + align:start position:0% +small butterfly structure where we have + + + align:start position:0% +small butterfly structure where we have +two inputs and two outputs + + align:start position:0% +two inputs and two outputs + + + align:start position:0% +two inputs and two outputs +and we will repeat this process and + + align:start position:0% +and we will repeat this process and + + + align:start position:0% +and we will repeat this process and +we'll do the same on each of these other + + align:start position:0% +we'll do the same on each of these other + + + align:start position:0% +we'll do the same on each of these other +levels so we forward those or we cross + + align:start position:0% + + + + align:start position:0% + +them like + + align:start position:0% + + + + align:start position:0% + +this and now that we have constructed + + align:start position:0% +this and now that we have constructed + + + align:start position:0% +this and now that we have constructed +all these smaller butterfly structures + + align:start position:0% +all these smaller butterfly structures + + + align:start position:0% +all these smaller butterfly structures +we can start to combine two butterfly + + align:start position:0% +we can start to combine two butterfly + + + align:start position:0% +we can start to combine two butterfly +structures together in the bigger one so + + align:start position:0% +structures together in the bigger one so + + + align:start position:0% +structures together in the bigger one so +here we had two outputs that we combined + + align:start position:0% +here we had two outputs that we combined + + + align:start position:0% +here we had two outputs that we combined +in a butterfly structure and now we use + + align:start position:0% +in a butterfly structure and now we use + + + align:start position:0% +in a butterfly structure and now we use +two butterfly structures that we can + + align:start position:0% +two butterfly structures that we can + + + align:start position:0% +two butterfly structures that we can +that we uh that we uh put into a bigger + + align:start position:0% +that we uh that we uh put into a bigger + + + align:start position:0% +that we uh that we uh put into a bigger +version so how do we do this well we + + align:start position:0% +version so how do we do this well we + + + align:start position:0% +version so how do we do this well we +have that the upper half over here can + + align:start position:0% +have that the upper half over here can + + + align:start position:0% +have that the upper half over here can +either forward + + align:start position:0% +either forward + + + align:start position:0% +either forward +those packets or cross them over to the + + align:start position:0% +those packets or cross them over to the + + + align:start position:0% +those packets or cross them over to the +bottom part butterfly + + align:start position:0% +bottom part butterfly + + + align:start position:0% +bottom part butterfly +structure so for these we can either + + align:start position:0% +structure so for these we can either + + + align:start position:0% +structure so for these we can either +forward them straight + + align:start position:0% +forward them straight + + + align:start position:0% +forward them straight +on or we can go to the + + align:start position:0% +on or we can go to the + + + align:start position:0% +on or we can go to the +top + + align:start position:0% +top + + + align:start position:0% +top +butterfly so you see that these two + + align:start position:0% +butterfly so you see that these two + + + align:start position:0% +butterfly so you see that these two +inputs these two switches either can + + align:start position:0% +inputs these two switches either can + + + align:start position:0% +inputs these two switches either can +forward packets to this sub butterfly + + align:start position:0% +forward packets to this sub butterfly + + + align:start position:0% +forward packets to this sub butterfly +Network or to the top butterfly Network + + align:start position:0% +Network or to the top butterfly Network + + + align:start position:0% +Network or to the top butterfly Network +now we'll continue this + + align:start position:0% +now we'll continue this + + + align:start position:0% +now we'll continue this +process and for this we'll do the same + + align:start position:0% +process and for this we'll do the same + + + align:start position:0% +process and for this we'll do the same +so we can either go straight or we go + + align:start position:0% +so we can either go straight or we go + + + align:start position:0% +so we can either go straight or we go +down and over here we can go straight or + + align:start position:0% +down and over here we can go straight or + + + align:start position:0% +down and over here we can go straight or +we can go to the top butterfly + + align:start position:0% +we can go to the top butterfly + + + align:start position:0% +we can go to the top butterfly +Network well now we uh have the + + align:start position:0% +Network well now we uh have the + + + align:start position:0% +Network well now we uh have the +final part where we combine essentially + + align:start position:0% +final part where we combine essentially + + + align:start position:0% +final part where we combine essentially +these two butterfly + + align:start position:0% +these two butterfly + + + align:start position:0% +these two butterfly +networks we have two butterfly networks + + align:start position:0% +networks we have two butterfly networks + + + align:start position:0% +networks we have two butterfly networks +created here now composed again of + + align:start position:0% +created here now composed again of + + + align:start position:0% +created here now composed again of +smaller ones now these two are being + + align:start position:0% +smaller ones now these two are being + + + align:start position:0% +smaller ones now these two are being +composed to this bigger butterfly + + align:start position:0% +composed to this bigger butterfly + + + align:start position:0% +composed to this bigger butterfly +Network again we take these four uh + + align:start position:0% +Network again we take these four uh + + + align:start position:0% +Network again we take these four uh +switches they can route their packets + + align:start position:0% +switches they can route their packets + + + align:start position:0% +switches they can route their packets +forward to the top butterfly sub Network + + align:start position:0% +forward to the top butterfly sub Network + + + align:start position:0% +forward to the top butterfly sub Network +or to the bottom one so they can either + + align:start position:0% +or to the bottom one so they can either + + + align:start position:0% +or to the bottom one so they can either +go straight ahead or this one can + + align:start position:0% +go straight ahead or this one can + + + align:start position:0% +go straight ahead or this one can +connect to the first over here this one + + align:start position:0% +connect to the first over here this one + + + align:start position:0% +connect to the first over here this one +to the second to the third and this to + + align:start position:0% +to the second to the third and this to + + + align:start position:0% +to the second to the third and this to +the fourth and in the same style these + + align:start position:0% +the fourth and in the same style these + + + align:start position:0% +the fourth and in the same style these +can forward them straight + + align:start position:0% +can forward them straight + + + align:start position:0% +can forward them straight +like this and then go + + align:start position:0% + + + + align:start position:0% + +up like + + align:start position:0% +up like + + + align:start position:0% +up like +this and these are all connected because + + align:start position:0% +this and these are all connected because + + + align:start position:0% +this and these are all connected because +in this example we'll just have an 8 by8 + + align:start position:0% +in this example we'll just have an 8 by8 + + + align:start position:0% +in this example we'll just have an 8 by8 +uh network but the fly Network we have + + align:start position:0% +uh network but the fly Network we have + + + align:start position:0% +uh network but the fly Network we have +inputs uh 0 to 7 + + align:start position:0% + + + + align:start position:0% + +okay so this is the butterfly Network in + + align:start position:0% +okay so this is the butterfly Network in + + + align:start position:0% +okay so this is the butterfly Network in +a way what you can see here you can see + + align:start position:0% +a way what you can see here you can see + + + align:start position:0% +a way what you can see here you can see +sort of the sort of the two-dimensional + + align:start position:0% +sort of the sort of the two-dimensional + + + align:start position:0% +sort of the sort of the two-dimensional +structure like we have rows and columns + + align:start position:0% +structure like we have rows and columns + + + align:start position:0% +structure like we have rows and columns +at the same time we can also see this + + align:start position:0% +at the same time we can also see this + + + align:start position:0% +at the same time we can also see this +binary sort of tree uh feeling we get + + align:start position:0% +binary sort of tree uh feeling we get + + + align:start position:0% +binary sort of tree uh feeling we get +from it which is that a switch can + + align:start position:0% +from it which is that a switch can + + + align:start position:0% +from it which is that a switch can +forward uh sort of uh its packets to + + align:start position:0% +forward uh sort of uh its packets to + + + align:start position:0% +forward uh sort of uh its packets to +either say the top uh butterfly or the + + align:start position:0% +either say the top uh butterfly or the + + + align:start position:0% +either say the top uh butterfly or the +bottom butterfly so there's a split in + + align:start position:0% +bottom butterfly so there's a split in + + + align:start position:0% +bottom butterfly so there's a split in +two H the same for this one right this + + align:start position:0% +two H the same for this one right this + + + align:start position:0% +two H the same for this one right this +one goes either to this butterfly + + align:start position:0% +one goes either to this butterfly + + + align:start position:0% +one goes either to this butterfly +Network or it goes to this butterfly + + align:start position:0% +Network or it goes to this butterfly + + + align:start position:0% +Network or it goes to this butterfly +Network so you have this three structure + + align:start position:0% +Network so you have this three structure + + + align:start position:0% +Network so you have this three structure +sort of embedded in this two-dimensional + + align:start position:0% +sort of embedded in this two-dimensional + + + align:start position:0% +sort of embedded in this two-dimensional +structure so what are the properties of + + align:start position:0% +structure so what are the properties of + + + align:start position:0% +structure so what are the properties of +this one so let me first Define um the + + align:start position:0% +this one so let me first Define um the + + + align:start position:0% +this one so let me first Define um the +um the uh like like in more form formal + + align:start position:0% +um the uh like like in more form formal + + + align:start position:0% +um the uh like like in more form formal +mathematics + + align:start position:0% +mathematics + + + align:start position:0% +mathematics +uh how the switches uh router packets so + + align:start position:0% +uh how the switches uh router packets so + + + align:start position:0% +uh how the switches uh router packets so +how their connections + + align:start position:0% +how their connections + + + align:start position:0% +how their connections +are um so in order to do that we're + + align:start position:0% +are um so in order to do that we're + + + align:start position:0% +are um so in order to do that we're +going to uh label each uh + + align:start position:0% + + + + align:start position:0% + +switch and the IDE is that we're going + + align:start position:0% +switch and the IDE is that we're going + + + align:start position:0% +switch and the IDE is that we're going +to label it by its row and by its column + + align:start position:0% +to label it by its row and by its column + + + align:start position:0% +to label it by its row and by its column +so we will have + + align:start position:0% +so we will have + + + align:start position:0% +so we will have +um uh The Columns are numbered by level + + align:start position:0% +um uh The Columns are numbered by level + + + align:start position:0% +um uh The Columns are numbered by level +zero level one + + align:start position:0% +zero level one + + + align:start position:0% +zero level one +level two level + + align:start position:0% +level two level + + + align:start position:0% +level two level +three um yes and uh the rows are these + + align:start position:0% +three um yes and uh the rows are these + + + align:start position:0% +three um yes and uh the rows are these +integers but we're going to represent + + align:start position:0% +integers but we're going to represent + + + align:start position:0% +integers but we're going to represent +them by binary numbers so zero would be + + align:start position:0% +them by binary numbers so zero would be + + + align:start position:0% +them by binary numbers so zero would be +0 0 0 0 0 1 0 1 0o 0 one 1 uh oops one0 + + align:start position:0% +0 0 0 0 0 1 0 1 0o 0 one 1 uh oops one0 + + + align:start position:0% +0 0 0 0 0 1 0 1 0o 0 one 1 uh oops one0 +0 one0 1 and then we got + + align:start position:0% +0 one0 1 and then we got + + + align:start position:0% +0 one0 1 and then we got +uh 1 1 Z and 1 11 + + align:start position:0% +uh 1 1 Z and 1 11 + + + align:start position:0% +uh 1 1 Z and 1 11 +one so for example this particular + + align:start position:0% +one so for example this particular + + + align:start position:0% +one so for example this particular +switch would be labeled by these three + + align:start position:0% +switch would be labeled by these three + + + align:start position:0% +switch would be labeled by these three +bits 0 01 and the integer number one + + align:start position:0% +bits 0 01 and the integer number one + + + align:start position:0% +bits 0 01 and the integer number one +this one would be + + align:start position:0% +this one would be + + + align:start position:0% +this one would be +011 and its column is uh indexed by + + align:start position:0% +011 and its column is uh indexed by + + + align:start position:0% +011 and its column is uh indexed by +integer + + align:start position:0% +integer + + + align:start position:0% +integer +two okay so a + + align:start position:0% + + + + align:start position:0% + +switch is uh + + align:start position:0% +switch is uh + + + align:start position:0% +switch is uh +uniquely um ident + + align:start position:0% + + + + align:start position:0% + +identified by its uh + + align:start position:0% +identified by its uh + + + align:start position:0% +identified by its uh +row and + + align:start position:0% + + + + align:start position:0% + +column uh we will have a + + align:start position:0% +column uh we will have a + + + align:start position:0% +column uh we will have a +B1 up to B logarithm of n which are the + + align:start position:0% +B1 up to B logarithm of n which are the + + + align:start position:0% +B1 up to B logarithm of n which are the +number of bits to represent the row + + align:start position:0% +number of bits to represent the row + + + align:start position:0% +number of bits to represent the row +indices and we finally have an integer L + + align:start position:0% +indices and we finally have an integer L + + + align:start position:0% +indices and we finally have an integer L +and this we will call the + + align:start position:0% +and this we will call the + + + align:start position:0% +and this we will call the +level + + align:start position:0% +level + + + align:start position:0% +level +so this particular switch either directs + + align:start position:0% +so this particular switch either directs + + + align:start position:0% +so this particular switch either directs +or or routes a packet to the switch that + + align:start position:0% +or or routes a packet to the switch that + + + align:start position:0% +or or routes a packet to the switch that +is indexed + + align:start position:0% +is indexed + + + align:start position:0% +is indexed +by um B1 up to and then we get b l + one + + align:start position:0% +by um B1 up to and then we get b l + one + + + align:start position:0% +by um B1 up to and then we get b l + one +and we take its complement so instead of + + align:start position:0% +and we take its complement so instead of + + + align:start position:0% +and we take its complement so instead of +if B+ one would be one we would have a + + align:start position:0% +if B+ one would be one we would have a + + + align:start position:0% +if B+ one would be one we would have a +zero here if it would be a zero we will + + align:start position:0% +zero here if it would be a zero we will + + + align:start position:0% +zero here if it would be a zero we will +have a one over here and + + align:start position:0% +have a one over here and + + + align:start position:0% +have a one over here and +but we repeat all the other bits and we + + align:start position:0% +but we repeat all the other bits and we + + + align:start position:0% +but we repeat all the other bits and we +get B log + + align:start position:0% +get B log + + + align:start position:0% +get B log +n and uh it routes its back to the next + + align:start position:0% +n and uh it routes its back to the next + + + align:start position:0% +n and uh it routes its back to the next +level so we will have l+ + + align:start position:0% +level so we will have l+ + + + align:start position:0% +level so we will have l+ +one another possibility is because there + + align:start position:0% +one another possibility is because there + + + align:start position:0% +one another possibility is because there +two outgoing + + align:start position:0% +two outgoing + + + align:start position:0% +two outgoing +edges is if we have just + + align:start position:0% +edges is if we have just + + + align:start position:0% +edges is if we have just +B1 and we just copy BL + one essentially + + align:start position:0% +B1 and we just copy BL + one essentially + + + align:start position:0% +B1 and we just copy BL + one essentially +we route the packet straight forward we + + align:start position:0% +we route the packet straight forward we + + + align:start position:0% +we route the packet straight forward we +don't don't do anything + + align:start position:0% +don't don't do anything + + + align:start position:0% +don't don't do anything +special we get B log n over here and + + align:start position:0% +special we get B log n over here and + + + align:start position:0% +special we get B log n over here and +then to the next level so for + + align:start position:0% +then to the next level so for + + + align:start position:0% +then to the next level so for +example let's see where we can see how + + align:start position:0% +example let's see where we can see how + + + align:start position:0% +example let's see where we can see how +this works so for example take um this + + align:start position:0% +this works so for example take um this + + + align:start position:0% +this works so for example take um this +particular switch we have uh 0 one 0 so + + align:start position:0% +particular switch we have uh 0 one 0 so + + + align:start position:0% +particular switch we have uh 0 one 0 so +it can either go straight on to the next + + align:start position:0% +it can either go straight on to the next + + + align:start position:0% +it can either go straight on to the next +level it would go to 0 one 0 but then + + align:start position:0% +level it would go to 0 one 0 but then + + + align:start position:0% +level it would go to 0 one 0 but then +instead of level one we have level two + + align:start position:0% +instead of level one we have level two + + + align:start position:0% +instead of level one we have level two +which is the right Edge over there + + align:start position:0% +which is the right Edge over there + + + align:start position:0% +which is the right Edge over there +um the other one is if this one goes up + + align:start position:0% +um the other one is if this one goes up + + + align:start position:0% +um the other one is if this one goes up +well uh we will need to uh switch the + + align:start position:0% +well uh we will need to uh switch the + + + align:start position:0% +well uh we will need to uh switch the +first um the first um uh uh bit over + + align:start position:0% +first um the first um uh uh bit over + + + align:start position:0% +first um the first um uh uh bit over +here uh one we swap it into zero and + + align:start position:0% +here uh one we swap it into zero and + + + align:start position:0% +here uh one we swap it into zero and +then we go to the three zeros over here + + align:start position:0% +then we go to the three zeros over here + + + align:start position:0% +then we go to the three zeros over here +and we go to the next level and that + + align:start position:0% +and we go to the next level and that + + + align:start position:0% +and we go to the next level and that +would be this particular + + align:start position:0% +would be this particular + + + align:start position:0% +would be this particular +rule so what we can do here is to so so + + align:start position:0% +rule so what we can do here is to so so + + + align:start position:0% +rule so what we can do here is to so so +with when we see this we can start to uh + + align:start position:0% +with when we see this we can start to uh + + + align:start position:0% +with when we see this we can start to uh +figure out how we can direct inputs to + + align:start position:0% +figure out how we can direct inputs to + + + align:start position:0% +figure out how we can direct inputs to +outputs okay so let's uh do + + align:start position:0% +outputs okay so let's uh do + + + align:start position:0% +outputs okay so let's uh do +this + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% + + + + align:start position:0% + +so suppose I want to uh uh route a + + align:start position:0% +so suppose I want to uh uh route a + + + align:start position:0% +so suppose I want to uh uh route a +packet from a certain input one of the + + align:start position:0% +packet from a certain input one of the + + + align:start position:0% +packet from a certain input one of the +one of these all the way to one of the + + align:start position:0% +one of these all the way to one of the + + + align:start position:0% +one of these all the way to one of the +outputs uh over here + + align:start position:0% +outputs uh over here + + + align:start position:0% +outputs uh over here +so the way to do this is as follows we + + align:start position:0% +so the way to do this is as follows we + + + align:start position:0% +so the way to do this is as follows we +can just start for example I want to go + + align:start position:0% +can just start for example I want to go + + + align:start position:0% +can just start for example I want to go +from switch X1 up to X log + + align:start position:0% +from switch X1 up to X log + + + align:start position:0% +from switch X1 up to X log +n comma comma zero so I start + + align:start position:0% +n comma comma zero so I start + + + align:start position:0% +n comma comma zero so I start +completely at the left over here and I + + align:start position:0% +completely at the left over here and I + + + align:start position:0% +completely at the left over here and I +want to go somewhere of my choice to the + + align:start position:0% +want to go somewhere of my choice to the + + + align:start position:0% +want to go somewhere of my choice to the +right so I want to somehow + + align:start position:0% +right so I want to somehow + + + align:start position:0% +right so I want to somehow +move all the way to some other row + + align:start position:0% +move all the way to some other row + + + align:start position:0% +move all the way to some other row +y1 index by y by the bit pattern y1 up + + align:start position:0% +y1 index by y by the bit pattern y1 up + + + align:start position:0% +y1 index by y by the bit pattern y1 up +to Y log n but now at the very last + + align:start position:0% +to Y log n but now at the very last + + + align:start position:0% +to Y log n but now at the very last +level um which is log n well how do I do + + align:start position:0% +level um which is log n well how do I do + + + align:start position:0% +level um which is log n well how do I do +it well this switch I can use that rule + + align:start position:0% +it well this switch I can use that rule + + + align:start position:0% +it well this switch I can use that rule +up there and simply change X1 to y1 I + + align:start position:0% +up there and simply change X1 to y1 I + + + align:start position:0% +up there and simply change X1 to y1 I +can either leave X1 as it is if it's the + + align:start position:0% +can either leave X1 as it is if it's the + + + align:start position:0% +can either leave X1 as it is if it's the +same as y1 or I can swap it to its + + align:start position:0% +same as y1 or I can swap it to its + + + align:start position:0% +same as y1 or I can swap it to its +complement if that's the value of y1 so + + align:start position:0% +complement if that's the value of y1 so + + + align:start position:0% +complement if that's the value of y1 so +what I can do is I can just simply route + + align:start position:0% +what I can do is I can just simply route + + + align:start position:0% +what I can do is I can just simply route +it to uh y1 and then I leave all the + + align:start position:0% +it to uh y1 and then I leave all the + + + align:start position:0% +it to uh y1 and then I leave all the +other bits the same which are X2 X3 all + + align:start position:0% +other bits the same which are X2 X3 all + + + align:start position:0% +other bits the same which are X2 X3 all +the way up to X log + + align:start position:0% +the way up to X log + + + align:start position:0% +the way up to X log +n and uh we will have um reached the + + align:start position:0% +n and uh we will have um reached the + + + align:start position:0% +n and uh we will have um reached the +first level + + align:start position:0% +first level + + + align:start position:0% +first level +now this one can go to well now I'm + + align:start position:0% +now this one can go to well now I'm + + + align:start position:0% +now this one can go to well now I'm +going to swap the second bit into the + + align:start position:0% +going to swap the second bit into the + + + align:start position:0% +going to swap the second bit into the +bit of my choice so I leave all the + + align:start position:0% +bit of my choice so I leave all the + + + align:start position:0% +bit of my choice so I leave all the +other bits the same y1 the same X3 all + + align:start position:0% +other bits the same y1 the same X3 all + + + align:start position:0% +other bits the same y1 the same X3 all +the others the same I just swap X2 into + + align:start position:0% +the others the same I just swap X2 into + + + align:start position:0% +the others the same I just swap X2 into +Y2 so we leave all those to + + align:start position:0% +Y2 so we leave all those to + + + align:start position:0% +Y2 so we leave all those to +equal and we go to the second level and + + align:start position:0% +equal and we go to the second level and + + + align:start position:0% +equal and we go to the second level and +then we go all the + + align:start position:0% +then we go all the + + + align:start position:0% +then we go all the +way to the final level and we one by one + + align:start position:0% +way to the final level and we one by one + + + align:start position:0% +way to the final level and we one by one +Swap all these bits so let's have an + + align:start position:0% +Swap all these bits so let's have an + + + align:start position:0% +Swap all these bits so let's have an +example um suppose I want to connect uh + + align:start position:0% +example um suppose I want to connect uh + + + align:start position:0% +example um suppose I want to connect uh +say uh this + + align:start position:0% +say uh this + + + align:start position:0% +say uh this +one to uh um for example well let's say + + align:start position:0% +one to uh um for example well let's say + + + align:start position:0% +one to uh um for example well let's say +this particular output + + align:start position:0% +this particular output + + + align:start position:0% +this particular output +so uh what's + + align:start position:0% +so uh what's + + + align:start position:0% +so uh what's +the what's the binary for this one this + + align:start position:0% +the what's the binary for this one this + + + align:start position:0% +the what's the binary for this one this +is actually 1 Z + + align:start position:0% +is actually 1 Z + + + align:start position:0% +is actually 1 Z + + align:start position:0% + + + align:start position:0% +so um if the first bit is different + + align:start position:0% +so um if the first bit is different + + + align:start position:0% +so um if the first bit is different +I need to cross and otherwise I need to + + align:start position:0% +I need to cross and otherwise I need to + + + align:start position:0% +I need to cross and otherwise I need to +pass straight on so let's do + + align:start position:0% +pass straight on so let's do + + + align:start position:0% +pass straight on so let's do +this so over here I'm in 0 one 1 I need + + align:start position:0% +this so over here I'm in 0 one 1 I need + + + align:start position:0% +this so over here I'm in 0 one 1 I need +to go to one Z one so I need to change + + align:start position:0% +to go to one Z one so I need to change + + + align:start position:0% +to go to one Z one so I need to change +the zero into a one so I need to go + + align:start position:0% +the zero into a one so I need to go + + + align:start position:0% +the zero into a one so I need to go +down I need to + + align:start position:0% + + + + align:start position:0% + +cross now uh if I look at the second bit + + align:start position:0% +cross now uh if I look at the second bit + + + align:start position:0% +cross now uh if I look at the second bit +um I also need to + + align:start position:0% +um I also need to + + + align:start position:0% +um I also need to +to change it into a zero so again I need + + align:start position:0% +to change it into a zero so again I need + + + align:start position:0% +to change it into a zero so again I need +to + + align:start position:0% +to + + + align:start position:0% +to +cross which is over + + align:start position:0% +cross which is over + + + align:start position:0% +cross which is over +here now the third bit is equal to + + align:start position:0% +here now the third bit is equal to + + + align:start position:0% +here now the third bit is equal to +one and it's the same so now I can go + + align:start position:0% +one and it's the same so now I can go + + + align:start position:0% +one and it's the same so now I can go +straight ahead I do not + + align:start position:0% +straight ahead I do not + + + align:start position:0% +straight ahead I do not +cross and I end up at this output so + + align:start position:0% +cross and I end up at this output so + + + align:start position:0% +cross and I end up at this output so +what do so what did I do for every bit + + align:start position:0% +what do so what did I do for every bit + + + align:start position:0% +what do so what did I do for every bit +that is different I cross and for the + + align:start position:0% +that is different I cross and for the + + + align:start position:0% +that is different I cross and for the +bits that are the same I go straight + + align:start position:0% +bits that are the same I go straight + + + align:start position:0% +bits that are the same I go straight +ahead so this is how I can route + + align:start position:0% +ahead so this is how I can route + + + align:start position:0% +ahead so this is how I can route +packets from one input to another + + align:start position:0% + + + + align:start position:0% + +output okay so let's uh look at the + + align:start position:0% +output okay so let's uh look at the + + + align:start position:0% +output okay so let's uh look at the +parameters um first of all if we look at + + align:start position:0% +parameters um first of all if we look at + + + align:start position:0% +parameters um first of all if we look at +the uh uh at the at the + + align:start position:0% +the uh uh at the at the + + + align:start position:0% +the uh uh at the at the +diameter well it turns out that that's + + align:start position:0% +diameter well it turns out that that's + + + align:start position:0% +diameter well it turns out that that's +equal approximately equal to the to the + + align:start position:0% +equal approximately equal to the to the + + + align:start position:0% +equal approximately equal to the to the +number of levels which is the logarithm + + align:start position:0% +number of levels which is the logarithm + + + align:start position:0% +number of levels which is the logarithm +of N and to be precise it's actually + + align:start position:0% +of N and to be precise it's actually + + + align:start position:0% +of N and to be precise it's actually +equal to 2 plus the logarithm of n so + + align:start position:0% +equal to 2 plus the logarithm of n so + + + align:start position:0% +equal to 2 plus the logarithm of n so +that's great that's a good uh that's a + + align:start position:0% +that's great that's a good uh that's a + + + align:start position:0% +that's great that's a good uh that's a +good scaling again it's back to the + + align:start position:0% +good scaling again it's back to the + + + align:start position:0% +good scaling again it's back to the +logarithm of n so we have the best of + + align:start position:0% +logarithm of n so we have the best of + + + align:start position:0% +logarithm of n so we have the best of +these two + + align:start position:0% +these two + + + align:start position:0% +these two +parameters the switches that we see have + + align:start position:0% +parameters the switches that we see have + + + align:start position:0% +parameters the switches that we see have +two inputs and two outputs so we again + + align:start position:0% +two inputs and two outputs so we again + + + align:start position:0% +two inputs and two outputs so we again +have a two * two + + align:start position:0% +have a two * two + + + align:start position:0% +have a two * two +switch um the number of switches is the + + align:start position:0% +switch um the number of switches is the + + + align:start position:0% +switch um the number of switches is the +number of rows times the number of + + align:start position:0% +number of rows times the number of + + + align:start position:0% +number of rows times the number of +columns the number of columns is the + + align:start position:0% +columns the number of columns is the + + + align:start position:0% +columns the number of columns is the +logarithm of N and number of rows is uh + + align:start position:0% +logarithm of N and number of rows is uh + + + align:start position:0% +logarithm of N and number of rows is uh +is equal to n and to make it a little + + align:start position:0% +is equal to n and to make it a little + + + align:start position:0% +is equal to n and to make it a little +bit precise it's 1 plus the logarithm of + + align:start position:0% +bit precise it's 1 plus the logarithm of + + + align:start position:0% +bit precise it's 1 plus the logarithm of +n so that's somewhere in between those + + align:start position:0% +n so that's somewhere in between those + + + align:start position:0% +n so that's somewhere in between those +two but if you're thinking about it it's + + align:start position:0% +two but if you're thinking about it it's + + + align:start position:0% +two but if you're thinking about it it's +much better than n Square it's almost + + align:start position:0% +much better than n Square it's almost + + + align:start position:0% +much better than n Square it's almost +linear except for a logarithmic + + align:start position:0% +linear except for a logarithmic + + + align:start position:0% +linear except for a logarithmic +factor for the congestion and we're not + + align:start position:0% +factor for the congestion and we're not + + + align:start position:0% +factor for the congestion and we're not +going to talk about it here but you have + + align:start position:0% +going to talk about it here but you have + + + align:start position:0% +going to talk about it here but you have +a problem set assignment that uh will + + align:start position:0% +a problem set assignment that uh will + + + align:start position:0% +a problem set assignment that uh will +ask you to solve this is that actually + + align:start position:0% +ask you to solve this is that actually + + + align:start position:0% +ask you to solve this is that actually +the congestion is a square root of n uh + + align:start position:0% +the congestion is a square root of n uh + + + align:start position:0% +the congestion is a square root of n uh +or + + align:start position:0% +or + + + align:start position:0% +or +is equal to the square root of n / 2 + + align:start position:0% +is equal to the square root of n / 2 + + + align:start position:0% +is equal to the square root of n / 2 +depending on whether n is an even power + + align:start position:0% +depending on whether n is an even power + + + align:start position:0% +depending on whether n is an even power +or n is an odd power now we're not going + + align:start position:0% +or n is an odd power now we're not going + + + align:start position:0% +or n is an odd power now we're not going +to prove that here because we want to + + align:start position:0% +to prove that here because we want to + + + align:start position:0% +to prove that here because we want to +step forward to this particular Network + + align:start position:0% +step forward to this particular Network + + + align:start position:0% +step forward to this particular Network +that's very + + align:start position:0% +that's very + + + align:start position:0% +that's very +exciting and uh you will prove this in + + align:start position:0% +exciting and uh you will prove this in + + + align:start position:0% +exciting and uh you will prove this in +your problem set so this one is + + align:start position:0% +your problem set so this one is + + + align:start position:0% +your problem set so this one is +somewhere in between somewhere in + + align:start position:0% +somewhere in between somewhere in + + + align:start position:0% +somewhere in between somewhere in +between these two extremes now it would + + align:start position:0% +between these two extremes now it would + + + align:start position:0% +between these two extremes now it would +be really fantastic if we can somehow + + align:start position:0% +be really fantastic if we can somehow + + + align:start position:0% +be really fantastic if we can somehow +transform this network with the trick to + + align:start position:0% +transform this network with the trick to + + + align:start position:0% +transform this network with the trick to +again have a really great congestion of + + align:start position:0% +again have a really great congestion of + + + align:start position:0% +again have a really great congestion of +just a constant like like like like two + + align:start position:0% +just a constant like like like like two + + + align:start position:0% +just a constant like like like like two +or or three or whatever or maybe even + + align:start position:0% +or or three or whatever or maybe even + + + align:start position:0% +or or three or whatever or maybe even +one so for this particular network uh in + + align:start position:0% +one so for this particular network uh in + + + align:start position:0% +one so for this particular network uh in +the 1960s Ben Babs researcher had the + + align:start position:0% +the 1960s Ben Babs researcher had the + + + align:start position:0% +the 1960s Ben Babs researcher had the +great idea to use a butterfly Network + + align:start position:0% +great idea to use a butterfly Network + + + align:start position:0% +great idea to use a butterfly Network +and attach to it again a butterfly + + align:start position:0% +and attach to it again a butterfly + + + align:start position:0% +and attach to it again a butterfly +Network backto back sort of so what was + + align:start position:0% +Network backto back sort of so what was + + + align:start position:0% +Network backto back sort of so what was +his ID his idea was to uh to do the + + align:start position:0% +his ID his idea was to uh to do the + + + align:start position:0% +his ID his idea was to uh to do the +following + + align:start position:0% +following + + + align:start position:0% +following +so the butterfly + + align:start position:0% +so the butterfly + + + align:start position:0% +so the butterfly +Network as we have it right now is this + + align:start position:0% +Network as we have it right now is this + + + align:start position:0% +Network as we have it right now is this +particular part over + + align:start position:0% +particular part over + + + align:start position:0% +particular part over +here and the idea is is to uh now to + + align:start position:0% +here and the idea is is to uh now to + + + align:start position:0% +here and the idea is is to uh now to +start up mixing all those outputs that + + align:start position:0% +start up mixing all those outputs that + + + align:start position:0% +start up mixing all those outputs that +we got here together again using a + + align:start position:0% +we got here together again using a + + + align:start position:0% +we got here together again using a +similar rule so what do we do we are + + align:start position:0% +similar rule so what do we do we are + + + align:start position:0% +similar rule so what do we do we are +going going to um to essentially + + align:start position:0% +going going to um to essentially + + + align:start position:0% +going going to um to essentially +um + + align:start position:0% + + + + align:start position:0% + +um uh repeat this particular structure + + align:start position:0% +um uh repeat this particular structure + + + align:start position:0% +um uh repeat this particular structure +on this + + align:start position:0% +on this + + + align:start position:0% +on this +side okay so how do we do it uh well we + + align:start position:0% +side okay so how do we do it uh well we + + + align:start position:0% +side okay so how do we do it uh well we +go either straight + + align:start position:0% + + + + align:start position:0% + +forward or we start to mix them again so + + align:start position:0% +forward or we start to mix them again so + + + align:start position:0% +forward or we start to mix them again so +it's like this output this particular + + align:start position:0% +it's like this output this particular + + + align:start position:0% +it's like this output this particular +switch can either go straight the head + + align:start position:0% +switch can either go straight the head + + + align:start position:0% +switch can either go straight the head +or can cross to the lower um part over + + align:start position:0% +or can cross to the lower um part over + + + align:start position:0% +or can cross to the lower um part over +here it goes over here and this one goes + + align:start position:0% +here it goes over here and this one goes + + + align:start position:0% +here it goes over here and this one goes +over here so as you can see we have + + align:start position:0% +over here so as you can see we have + + + align:start position:0% +over here so as you can see we have +repeated this + + align:start position:0% +repeated this + + + align:start position:0% +repeated this +part is exactly the same as this + + align:start position:0% +part is exactly the same as this + + + align:start position:0% +part is exactly the same as this +structure over here and we'll we'll do + + align:start position:0% +structure over here and we'll we'll do + + + align:start position:0% +structure over here and we'll we'll do +the + + align:start position:0% + + + + align:start position:0% + +same for the this + + align:start position:0% +same for the this + + + align:start position:0% +same for the this +part so we can either + + align:start position:0% +part so we can either + + + align:start position:0% +part so we can either +Cross or we can go straight ahead oh uh + + align:start position:0% +Cross or we can go straight ahead oh uh + + + align:start position:0% +Cross or we can go straight ahead oh uh +we also have of course that these + + align:start position:0% +we also have of course that these + + + align:start position:0% +we also have of course that these +switches can go straight ahead or can + + align:start position:0% +switches can go straight ahead or can + + + align:start position:0% +switches can go straight ahead or can +cross to the top I forgot about that so + + align:start position:0% +cross to the top I forgot about that so + + + align:start position:0% +cross to the top I forgot about that so +we have this oops as well so as you can + + align:start position:0% +we have this oops as well so as you can + + + align:start position:0% +we have this oops as well so as you can +see this particular structure repeats + + align:start position:0% +see this particular structure repeats + + + align:start position:0% +see this particular structure repeats +itself again and we slowly start to + + align:start position:0% +itself again and we slowly start to + + + align:start position:0% +itself again and we slowly start to +build up and mixing all the uh outputs + + align:start position:0% +build up and mixing all the uh outputs + + + align:start position:0% +build up and mixing all the uh outputs +again or the possibility at least to + + align:start position:0% +again or the possibility at least to + + + align:start position:0% +again or the possibility at least to +Route them to any other uh to any other + + align:start position:0% +Route them to any other uh to any other + + + align:start position:0% +Route them to any other uh to any other +U um row so how do we do this well we + + align:start position:0% +U um row so how do we do this well we + + + align:start position:0% +U um row so how do we do this well we +Contin this particular structure now + + align:start position:0% +Contin this particular structure now + + + align:start position:0% +Contin this particular structure now +over here so all these can either go + + align:start position:0% +over here so all these can either go + + + align:start position:0% +over here so all these can either go +straight + + align:start position:0% + + + + align:start position:0% + +ahead that's a + + align:start position:0% + + + + align:start position:0% + +possibility or they can go + + align:start position:0% +possibility or they can go + + + align:start position:0% +possibility or they can go +all + + align:start position:0% + + + + align:start position:0% + +down so this switch can either go + + align:start position:0% +down so this switch can either go + + + align:start position:0% +down so this switch can either go +straight ahead or can go to the lower + + align:start position:0% +straight ahead or can go to the lower + + + align:start position:0% +straight ahead or can go to the lower +half and for this we have a similar Circ + + align:start position:0% +half and for this we have a similar Circ + + + align:start position:0% +half and for this we have a similar Circ +so we can either go straight + + align:start position:0% + + + + align:start position:0% + +ahead or such a switch can cross over to + + align:start position:0% +ahead or such a switch can cross over to + + + align:start position:0% +ahead or such a switch can cross over to +the + + align:start position:0% +the + + + align:start position:0% +the +top over + + align:start position:0% +top over + + + align:start position:0% +top over +here + + align:start position:0% + + + + align:start position:0% + +okay so that's this so this is bayis + + align:start position:0% +okay so that's this so this is bayis + + + align:start position:0% +okay so that's this so this is bayis +network and then over here of course we + + align:start position:0% +network and then over here of course we + + + align:start position:0% +network and then over here of course we +have uh the outputs + + align:start position:0% +have uh the outputs + + + align:start position:0% +have uh the outputs +[Music] + + align:start position:0% + + + + align:start position:0% + +zero one and all the way down + + align:start position:0% + + + + align:start position:0% + +to + + align:start position:0% + + + + align:start position:0% + +seven + + align:start position:0% +seven + + + align:start position:0% +seven +okay so as you can see over here this + + align:start position:0% +okay so as you can see over here this + + + align:start position:0% +okay so as you can see over here this +structure again has a recursive nature + + align:start position:0% +structure again has a recursive nature + + + align:start position:0% +structure again has a recursive nature +to it um you can see that uh this big + + align:start position:0% +to it um you can see that uh this big + + + align:start position:0% +to it um you can see that uh this big +benis network over here consists of two + + align:start position:0% +benis network over here consists of two + + + align:start position:0% +benis network over here consists of two +smaller ones that are right here in the + + align:start position:0% +smaller ones that are right here in the + + + align:start position:0% +smaller ones that are right here in the +middle this one that goes all the way up + + align:start position:0% +middle this one that goes all the way up + + + align:start position:0% +middle this one that goes all the way up +to here so maybe I should put uh a color + + align:start position:0% +to here so maybe I should put uh a color + + + align:start position:0% +to here so maybe I should put uh a color +boundary around it let me + + align:start position:0% +boundary around it let me + + + align:start position:0% +boundary around it let me +check I want to do + + align:start position:0% + + + + align:start position:0% + +this right so this particular + + align:start position:0% + + + + align:start position:0% + +part is again a bis Network and um the + + align:start position:0% +part is again a bis Network and um the + + + align:start position:0% +part is again a bis Network and um the +top part in the same picture the top sub + + align:start position:0% +top part in the same picture the top sub + + + align:start position:0% +top part in the same picture the top sub +network is also a bis Network this + + align:start position:0% + + + + align:start position:0% + +part and if you look within those we + + align:start position:0% +part and if you look within those we + + + align:start position:0% +part and if you look within those we +again see a top + + align:start position:0% +again see a top + + + align:start position:0% +again see a top +part and a bottom part and over here we + + align:start position:0% +part and a bottom part and over here we + + + align:start position:0% +part and a bottom part and over here we +see a top part and also a bottom part so + + align:start position:0% +see a top part and also a bottom part so + + + align:start position:0% +see a top part and also a bottom part so +so um you see this uh recursive nature + + align:start position:0% +so um you see this uh recursive nature + + + align:start position:0% +so um you see this uh recursive nature +again reappearing it turns out that with + + align:start position:0% +again reappearing it turns out that with + + + align:start position:0% +again reappearing it turns out that with +this trick we can completely eliminate + + align:start position:0% +this trick we can completely eliminate + + + align:start position:0% +this trick we can completely eliminate +congestion and we can get it to only one + + align:start position:0% +congestion and we can get it to only one + + + align:start position:0% +congestion and we can get it to only one +which is really surprising and that's + + align:start position:0% +which is really surprising and that's + + + align:start position:0% +which is really surprising and that's +what we're going to prove here so this + + align:start position:0% +what we're going to prove here so this + + + align:start position:0% +what we're going to prove here so this +is a great uh invention at the time it's + + align:start position:0% +is a great uh invention at the time it's + + + align:start position:0% +is a great uh invention at the time it's +really really + + align:start position:0% +really really + + + align:start position:0% +really really +beautiful um so let me put in the other + + align:start position:0% +beautiful um so let me put in the other + + + align:start position:0% +beautiful um so let me put in the other +parameters um so they stay approximately + + align:start position:0% +parameters um so they stay approximately + + + align:start position:0% +parameters um so they stay approximately +the same up to that diameter is about + + align:start position:0% +the same up to that diameter is about + + + align:start position:0% +the same up to that diameter is about +twice as large because we added another + + align:start position:0% +twice as large because we added another + + + align:start position:0% +twice as large because we added another +sort of whole butterfly structure to it + + align:start position:0% +sort of whole butterfly structure to it + + + align:start position:0% +sort of whole butterfly structure to it +the switches size and stay the same we + + align:start position:0% +the switches size and stay the same we + + + align:start position:0% +the switches size and stay the same we +again have about two times more + + align:start position:0% + + + + align:start position:0% + +switches so they sort of stay about the + + align:start position:0% +switches so they sort of stay about the + + + align:start position:0% +switches so they sort of stay about the +same up to a linear uh Factor like a + + align:start position:0% +same up to a linear uh Factor like a + + + align:start position:0% +same up to a linear uh Factor like a +constant factor and uh the congestion + + align:start position:0% +constant factor and uh the congestion + + + align:start position:0% +constant factor and uh the congestion +however completely dropped down to one + + align:start position:0% +however completely dropped down to one + + + align:start position:0% +however completely dropped down to one +so that's what we're going to prove now + + align:start position:0% +so that's what we're going to prove now + + + align:start position:0% +so that's what we're going to prove now +and in order to get some + + align:start position:0% +and in order to get some + + + align:start position:0% +and in order to get some +intuition well let me first write down + + align:start position:0% +intuition well let me first write down + + + align:start position:0% +intuition well let me first write down +the + + align:start position:0% +the + + + align:start position:0% +the +theorem + + align:start position:0% +theorem + + + align:start position:0% +theorem +um actually let me put + + align:start position:0% +um actually let me put + + + align:start position:0% +um actually let me put +this uh over + + align:start position:0% + + + + align:start position:0% + +here so in order to get some insight + + align:start position:0% +here so in order to get some insight + + + align:start position:0% +here so in order to get some insight +into this uh we are going to + + align:start position:0% +into this uh we are going to + + + align:start position:0% +into this uh we are going to +um well + + align:start position:0% +um well + + + align:start position:0% +um well +we we are going to use this recursive + + align:start position:0% +we we are going to use this recursive + + + align:start position:0% +we we are going to use this recursive +name nature so we're going to use + + align:start position:0% +name nature so we're going to use + + + align:start position:0% +name nature so we're going to use +induction and we're going to say + + align:start position:0% +induction and we're going to say + + + align:start position:0% +induction and we're going to say +oh I'm I can really for any permutation + + align:start position:0% +oh I'm I can really for any permutation + + + align:start position:0% +oh I'm I can really for any permutation +I can find a really good routing for say + + align:start position:0% +I can find a really good routing for say + + + align:start position:0% +I can find a really good routing for say +this red sub Network and for this blue + + align:start position:0% +this red sub Network and for this blue + + + align:start position:0% +this red sub Network and for this blue +sub Network so I know that so what I + + align:start position:0% +sub Network so I know that so what I + + + align:start position:0% +sub Network so I know that so what I +need to do is to to to if if if I have + + align:start position:0% +need to do is to to to if if if I have + + + align:start position:0% +need to do is to to to if if if I have +my bigger Banis Network like this one I + + align:start position:0% +my bigger Banis Network like this one I + + + align:start position:0% +my bigger Banis Network like this one I +would need to somehow map these + + align:start position:0% +would need to somehow map these + + + align:start position:0% +would need to somehow map these +inputs uh I need to Route them to either + + align:start position:0% +inputs uh I need to Route them to either + + + align:start position:0% +inputs uh I need to Route them to either +the top and the bottom sub Network one + + align:start position:0% +the top and the bottom sub Network one + + + align:start position:0% +the top and the bottom sub Network one +of the two in such a way that there will + + align:start position:0% +of the two in such a way that there will + + + align:start position:0% +of the two in such a way that there will +be absolutely no congestion because we + + align:start position:0% +be absolutely no congestion because we + + + align:start position:0% +be absolutely no congestion because we +want to keep this one so a switch should + + align:start position:0% +want to keep this one so a switch should + + + align:start position:0% +want to keep this one so a switch should +only see one packet coming in so that + + align:start position:0% +only see one packet coming in so that + + + align:start position:0% +only see one packet coming in so that +means for example and we'll come back to + + align:start position:0% +means for example and we'll come back to + + + align:start position:0% +means for example and we'll come back to +that that for example for this switch it + + align:start position:0% +that that for example for this switch it + + + align:start position:0% +that that for example for this switch it +should not receive a packet from both + + align:start position:0% +should not receive a packet from both + + + align:start position:0% +should not receive a packet from both +this input and from this input so the + + align:start position:0% +this input and from this input so the + + + align:start position:0% +this input and from this input so the +intuition that we are going to create is + + align:start position:0% +intuition that we are going to create is + + + align:start position:0% +intuition that we are going to create is +we're going to uh create like we we we + + align:start position:0% +we're going to uh create like we we we + + + align:start position:0% +we're going to uh create like we we we +we we going to list our constraints the + + align:start position:0% +we we going to list our constraints the + + + align:start position:0% +we we going to list our constraints the +constraints that we need to satisfy like + + align:start position:0% +constraints that we need to satisfy like + + + align:start position:0% +constraints that we need to satisfy like +the zero and the fourth input should not + + align:start position:0% +the zero and the fourth input should not + + + align:start position:0% +the zero and the fourth input should not +both be mapped to this top sub Network + + align:start position:0% +both be mapped to this top sub Network + + + align:start position:0% +both be mapped to this top sub Network +and so on so we will get into that and + + align:start position:0% +and so on so we will get into that and + + + align:start position:0% +and so on so we will get into that and +then we will uh gain a lot of intuition + + align:start position:0% +then we will uh gain a lot of intuition + + + align:start position:0% +then we will uh gain a lot of intuition +on how to solve this okay so what's the + + align:start position:0% +on how to solve this okay so what's the + + + align:start position:0% +on how to solve this okay so what's the +theorem so the theorem is that the uh + + align:start position:0% + + + + align:start position:0% + +congestion uh of uh uh the N + + align:start position:0% +congestion uh of uh uh the N + + + align:start position:0% +congestion uh of uh uh the N +input uh + + align:start position:0% +input uh + + + align:start position:0% +input uh +Bish + + align:start position:0% + + + + align:start position:0% + +network uh is actually equal to + + align:start position:0% +network uh is actually equal to + + + align:start position:0% +network uh is actually equal to +one uh and we will prove this for uh n + + align:start position:0% +one uh and we will prove this for uh n + + + align:start position:0% +one uh and we will prove this for uh n +equal to a power of two we have assumed + + align:start position:0% +equal to a power of two we have assumed + + + align:start position:0% +equal to a power of two we have assumed +that at the start of of of of with all + + align:start position:0% +that at the start of of of of with all + + + align:start position:0% +that at the start of of of of with all +the other networks as well and and in + + align:start position:0% +the other networks as well and and in + + + align:start position:0% +the other networks as well and and in +this case + + align:start position:0% +this case + + + align:start position:0% +this case +we will use induction on a so that's + + align:start position:0% +we will use induction on a so that's + + + align:start position:0% +we will use induction on a so that's +uh the method that we will do because + + align:start position:0% +uh the method that we will do because + + + align:start position:0% +uh the method that we will do because +that's also the recursive structure of + + align:start position:0% +that's also the recursive structure of + + + align:start position:0% +that's also the recursive structure of +the bis Network itself so we will use + + align:start position:0% + + + + align:start position:0% + +induction on a + + align:start position:0% +induction on a + + + align:start position:0% +induction on a +and uh we're going to define the + + align:start position:0% +and uh we're going to define the + + + align:start position:0% +and uh we're going to define the +induction hypothesis simply as the + + align:start position:0% +induction hypothesis simply as the + + + align:start position:0% +induction hypothesis simply as the +theorem is true for a + + align:start position:0% + + + + align:start position:0% + +okay now let us do the base case we + + align:start position:0% +okay now let us do the base case we + + + align:start position:0% +okay now let us do the base case we +always start with the base case and that + + align:start position:0% +always start with the base case and that + + + align:start position:0% +always start with the base case and that +should be pretty easy because this is + + align:start position:0% +should be pretty easy because this is + + + align:start position:0% +should be pretty easy because this is +the most basic uh Bish Network so n + + align:start position:0% +the most basic uh Bish Network so n + + + align:start position:0% +the most basic uh Bish Network so n +equal 2 the^ + + align:start position:0% +equal 2 the^ + + + align:start position:0% +equal 2 the^ +1 um we essentially have uh two inputs + + align:start position:0% +1 um we essentially have uh two inputs + + + align:start position:0% +1 um we essentially have uh two inputs +an input + + align:start position:0% +an input + + + align:start position:0% +an input +zero and an input one + + align:start position:0% +zero and an input one + + + align:start position:0% +zero and an input one +uh they are connected to these switches + + align:start position:0% +uh they are connected to these switches + + + align:start position:0% +uh they are connected to these switches +over here that can either forward + + align:start position:0% +over here that can either forward + + + align:start position:0% +over here that can either forward +them or can cross them over and then + + align:start position:0% +them or can cross them over and then + + + align:start position:0% +them or can cross them over and then +they go directly to the output uh notice + + align:start position:0% +they go directly to the output uh notice + + + align:start position:0% +they go directly to the output uh notice +that in this case you just have the most + + align:start position:0% +that in this case you just have the most + + + align:start position:0% +that in this case you just have the most +Elementary butterfly network is the + + align:start position:0% +Elementary butterfly network is the + + + align:start position:0% +Elementary butterfly network is the +same so we have output zero and output + + align:start position:0% +same so we have output zero and output + + + align:start position:0% +same so we have output zero and output +one so this corresponds in this picture + + align:start position:0% +one so this corresponds in this picture + + + align:start position:0% +one so this corresponds in this picture +to these little small things over here + + align:start position:0% +to these little small things over here + + + align:start position:0% +to these little small things over here +this one and this one and this one over + + align:start position:0% +this one and this one and this one over + + + align:start position:0% +this one and this one and this one over +here and the fourth one over here um so + + align:start position:0% +here and the fourth one over here um so + + + align:start position:0% +here and the fourth one over here um so +now let's take any permutation we want + + align:start position:0% +now let's take any permutation we want + + + align:start position:0% +now let's take any permutation we want +to show that we can route it in such a + + align:start position:0% +to show that we can route it in such a + + + align:start position:0% +to show that we can route it in such a +way that there's only a congestion of + + align:start position:0% +way that there's only a congestion of + + + align:start position:0% +way that there's only a congestion of +one so let's do this + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% + + + + align:start position:0% + +so so there are essentially only two + + align:start position:0% +so so there are essentially only two + + + align:start position:0% +so so there are essentially only two +permutations either zero is mapped to + + align:start position:0% +permutations either zero is mapped to + + + align:start position:0% +permutations either zero is mapped to +zero and one is mapped to one or zero is + + align:start position:0% +zero and one is mapped to one or zero is + + + align:start position:0% +zero and one is mapped to one or zero is +mapped to one and one is mapped to + + align:start position:0% +mapped to one and one is mapped to + + + align:start position:0% +mapped to one and one is mapped to +zero + + align:start position:0% +zero + + + align:start position:0% +zero +um so in both cases we can just route + + align:start position:0% +um so in both cases we can just route + + + align:start position:0% +um so in both cases we can just route +them uh through their own + + align:start position:0% +them uh through their own + + + align:start position:0% +them uh through their own +switches so we have that either Pi of 0 + + align:start position:0% +switches so we have that either Pi of 0 + + + align:start position:0% +switches so we have that either Pi of 0 +equals 0 and Pi of 1 equals 1 in which + + align:start position:0% +equals 0 and Pi of 1 equals 1 in which + + + align:start position:0% +equals 0 and Pi of 1 equals 1 in which +case we just direct them straight + + align:start position:0% +case we just direct them straight + + + align:start position:0% +case we just direct them straight +through and we go straight through and + + align:start position:0% +through and we go straight through and + + + align:start position:0% +through and we go straight through and +every switch which only sees a packet + + align:start position:0% +every switch which only sees a packet + + + align:start position:0% +every switch which only sees a packet +once so for this particular permutation + + align:start position:0% +once so for this particular permutation + + + align:start position:0% +once so for this particular permutation +we have a congestion of one now the + + align:start position:0% +we have a congestion of one now the + + + align:start position:0% +we have a congestion of one now the +other permutation that we can have is if + + align:start position:0% +other permutation that we can have is if + + + align:start position:0% +other permutation that we can have is if +zero is mapped to one and if one is + + align:start position:0% +zero is mapped to one and if one is + + + align:start position:0% +zero is mapped to one and if one is +mapped to zero well in that + + align:start position:0% +mapped to zero well in that + + + align:start position:0% +mapped to zero well in that +case we just route this cross over to + + align:start position:0% +case we just route this cross over to + + + align:start position:0% +case we just route this cross over to +the bottom row and here we go from this + + align:start position:0% +the bottom row and here we go from this + + + align:start position:0% +the bottom row and here we go from this +switch to the to the top row again every + + align:start position:0% +switch to the to the top row again every + + + align:start position:0% +switch to the to the top row again every +switch only sees a packet once so in + + align:start position:0% +switch only sees a packet once so in + + + align:start position:0% +switch only sees a packet once so in +this case in the base case we are done + + align:start position:0% +this case in the base case we are done + + + align:start position:0% +this case in the base case we are done +we are happy we have shown that the + + align:start position:0% +we are happy we have shown that the + + + align:start position:0% +we are happy we have shown that the +congestion is equal to one so now we get + + align:start position:0% +congestion is equal to one so now we get + + + align:start position:0% +congestion is equal to one so now we get +to uh the harder part because for the + + align:start position:0% +to uh the harder part because for the + + + align:start position:0% +to uh the harder part because for the +inductive + + align:start position:0% +inductive + + + align:start position:0% +inductive +step we are going to assume of + + align:start position:0% +step we are going to assume of + + + align:start position:0% +step we are going to assume of +course uh that it holds true for a + + align:start position:0% +course uh that it holds true for a + + + align:start position:0% +course uh that it holds true for a +smaller uh bis Network so we + + align:start position:0% +smaller uh bis Network so we + + + align:start position:0% +smaller uh bis Network so we +assume that uh p a is true + + align:start position:0% +assume that uh p a is true + + + align:start position:0% +assume that uh p a is true +and uh well let's try to gain some + + align:start position:0% +and uh well let's try to gain some + + + align:start position:0% +and uh well let's try to gain some +inside + + align:start position:0% +inside + + + align:start position:0% +inside +here so we know that within each from + + align:start position:0% +here so we know that within each from + + + align:start position:0% +here so we know that within each from +our induction hypothesis within each + + align:start position:0% +our induction hypothesis within each + + + align:start position:0% +our induction hypothesis within each +subn Network we can achieve a we can + + align:start position:0% +subn Network we can achieve a we can + + + align:start position:0% +subn Network we can achieve a we can +solve any routing problem with + + align:start position:0% +solve any routing problem with + + + align:start position:0% +solve any routing problem with +congestion one and for this sub Network + + align:start position:0% +congestion one and for this sub Network + + + align:start position:0% +congestion one and for this sub Network +the same that's our induction + + align:start position:0% +the same that's our induction + + + align:start position:0% +the same that's our induction +hypothesis so how do we go ahead we need + + align:start position:0% +hypothesis so how do we go ahead we need + + + align:start position:0% +hypothesis so how do we go ahead we need +to uh somehow map these inputs according + + align:start position:0% +to uh somehow map these inputs according + + + align:start position:0% +to uh somehow map these inputs according +to the permutation of our choice so that + + align:start position:0% +to the permutation of our choice so that + + + align:start position:0% +to the permutation of our choice so that +could be for example input zero goes to + + align:start position:0% +could be for example input zero goes to + + + align:start position:0% +could be for example input zero goes to +Output five or input one goes to Output + + align:start position:0% +Output five or input one goes to Output + + + align:start position:0% +Output five or input one goes to Output +two Etc so somehow we need to choose + + align:start position:0% +two Etc so somehow we need to choose + + + align:start position:0% +two Etc so somehow we need to choose +where we are going to map this + + align:start position:0% +where we are going to map this + + + align:start position:0% +where we are going to map this +particular input too so the packet that + + align:start position:0% +particular input too so the packet that + + + align:start position:0% +particular input too so the packet that +goes packet zero that comes from this + + align:start position:0% +goes packet zero that comes from this + + + align:start position:0% +goes packet zero that comes from this +input should either go to the red + + align:start position:0% +input should either go to the red + + + align:start position:0% +input should either go to the red +Network or it should go to the blue + + align:start position:0% +Network or it should go to the blue + + + align:start position:0% +Network or it should go to the blue +Network and for each of these inputs we + + align:start position:0% +Network and for each of these inputs we + + + align:start position:0% +Network and for each of these inputs we +can make such a choice but we have to be + + align:start position:0% +can make such a choice but we have to be + + + align:start position:0% +can make such a choice but we have to be +very smart about it because we need to + + align:start position:0% +very smart about it because we need to + + + align:start position:0% +very smart about it because we need to +avoid any + + align:start position:0% +avoid any + + + align:start position:0% +avoid any +congestion so the intuition is is that + + align:start position:0% +congestion so the intuition is is that + + + align:start position:0% +congestion so the intuition is is that +we're going to uh set up a constrained + + align:start position:0% +we're going to uh set up a constrained + + + align:start position:0% +we're going to uh set up a constrained +uh gra uh uh graph a graph that that + + align:start position:0% +uh gra uh uh graph a graph that that + + + align:start position:0% +uh gra uh uh graph a graph that that +that uh represents all the constraints + + align:start position:0% +that uh represents all the constraints + + + align:start position:0% +that uh represents all the constraints +that we need to satisfy in order to + + align:start position:0% +that we need to satisfy in order to + + + align:start position:0% +that we need to satisfy in order to +achieve congestion of + + align:start position:0% +achieve congestion of + + + align:start position:0% +achieve congestion of +one so let's do an example so that we + + align:start position:0% +one so let's do an example so that we + + + align:start position:0% +one so let's do an example so that we +can figure out what's going on actually + + align:start position:0% +can figure out what's going on actually + + + align:start position:0% +can figure out what's going on actually +let me put that over + + align:start position:0% +let me put that over + + + align:start position:0% +let me put that over +here so the so just take an example + + align:start position:0% +here so the so just take an example + + + align:start position:0% +here so the so just take an example +permutation and we'll go through this + + align:start position:0% +permutation and we'll go through this + + + align:start position:0% +permutation and we'll go through this +example and then see how uh the proof + + align:start position:0% + + + + align:start position:0% + +works so let's as an example have Pi of + + align:start position:0% +works so let's as an example have Pi of + + + align:start position:0% +works so let's as an example have Pi of +zero maps to + + align:start position:0% +zero maps to + + + align:start position:0% +zero maps to +one Pi of 1 maps to + + align:start position:0% +one Pi of 1 maps to + + + align:start position:0% +one Pi of 1 maps to +five Pi of two goes to + + align:start position:0% +five Pi of two goes to + + + align:start position:0% +five Pi of two goes to +four input three goes to seven um + + align:start position:0% +four input three goes to seven um + + + align:start position:0% +four input three goes to seven um +four maps to + + align:start position:0% +four maps to + + + align:start position:0% +four maps to +three 5 to + + align:start position:0% +three 5 to + + + align:start position:0% +three 5 to +six 6 + + align:start position:0% +six 6 + + + align:start position:0% +six 6 +to0 and 7 to2 so it's just an arbitrary + + align:start position:0% +to0 and 7 to2 so it's just an arbitrary + + + align:start position:0% +to0 and 7 to2 so it's just an arbitrary +permutation and + + align:start position:0% +permutation and + + + align:start position:0% +permutation and +um okay so what do we see we want to + + align:start position:0% +um okay so what do we see we want to + + + align:start position:0% +um okay so what do we see we want to +make sure that for example this switch + + align:start position:0% +make sure that for example this switch + + + align:start position:0% +make sure that for example this switch +is only seeing one packet so it cannot + + align:start position:0% +is only seeing one packet so it cannot + + + align:start position:0% +is only seeing one packet so it cannot +see a + + align:start position:0% +see a + + + align:start position:0% +see a +packet both coming from input zero as + + align:start position:0% +packet both coming from input zero as + + + align:start position:0% +packet both coming from input zero as +well as from input four I cannot see + + align:start position:0% +well as from input four I cannot see + + + align:start position:0% +well as from input four I cannot see +that I do not want that to happen + + align:start position:0% +that I do not want that to happen + + + align:start position:0% +that I do not want that to happen +similarly for this one I do not want to + + align:start position:0% +similarly for this one I do not want to + + + align:start position:0% +similarly for this one I do not want to +see a packet coming from one or one from + + align:start position:0% +see a packet coming from one or one from + + + align:start position:0% +see a packet coming from one or one from +five so let me Define a constrainted + + align:start position:0% +five so let me Define a constrainted + + + align:start position:0% +five so let me Define a constrainted +graph that sort of represents + + align:start position:0% +graph that sort of represents + + + align:start position:0% +graph that sort of represents +this + + align:start position:0% +this + + + align:start position:0% +this +so the constraint graph that we are + + align:start position:0% +so the constraint graph that we are + + + align:start position:0% +so the constraint graph that we are +interested + + align:start position:0% +interested + + + align:start position:0% +interested +in is defined as + + align:start position:0% +in is defined as + + + align:start position:0% +in is defined as +follows uh + + align:start position:0% +follows uh + + + align:start position:0% +follows uh +um if two + + align:start position:0% + + + + align:start position:0% + +packets + + align:start position:0% +packets + + + align:start position:0% +packets +uh if two packets must + + align:start position:0% + + + + align:start position:0% + +pass through different + + align:start position:0% +pass through different + + + align:start position:0% +pass through different +networks uh sub + + align:start position:0% + + + + align:start position:0% + +networks so in our case the red in the + + align:start position:0% +networks so in our case the red in the + + + align:start position:0% +networks so in our case the red in the +blue sub Network + + align:start position:0% + + + + align:start position:0% + +then we'll actually um have an edge + + align:start position:0% +then we'll actually um have an edge + + + align:start position:0% +then we'll actually um have an edge +between those two + + align:start position:0% +between those two + + + align:start position:0% +between those two +so + + align:start position:0% +so + + + align:start position:0% +so +then there is an + + align:start position:0% +then there is an + + + align:start position:0% +then there is an +edge uh between them so for this example + + align:start position:0% +edge uh between them so for this example + + + align:start position:0% +edge uh between them so for this example +we're going to set up this constraint + + align:start position:0% +we're going to set up this constraint + + + align:start position:0% +we're going to set up this constraint +graph + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% + + + + align:start position:0% + +um so I was just talking about this + + align:start position:0% +um so I was just talking about this + + + align:start position:0% +um so I was just talking about this +particular switch it cannot see one + + align:start position:0% +particular switch it cannot see one + + + align:start position:0% +particular switch it cannot see one +coming from four and a packet from zero + + align:start position:0% +coming from four and a packet from zero + + + align:start position:0% +coming from four and a packet from zero +so what we do what we have we have an + + align:start position:0% +so what we do what we have we have an + + + align:start position:0% +so what we do what we have we have an +edge between zero and four in the same + + align:start position:0% +edge between zero and four in the same + + + align:start position:0% +edge between zero and four in the same +way we have an edge from uh one to five + + align:start position:0% +way we have an edge from uh one to five + + + align:start position:0% +way we have an edge from uh one to five +why because a packet that that comes + + align:start position:0% +why because a packet that that comes + + + align:start position:0% +why because a packet that that comes +from input one and a packet that comes + + align:start position:0% +from input one and a packet that comes + + + align:start position:0% +from input one and a packet that comes +from from output F from input five + + align:start position:0% +from from output F from input five + + + align:start position:0% +from from output F from input five +cannot both be routed through this + + align:start position:0% +cannot both be routed through this + + + align:start position:0% +cannot both be routed through this +switch because then the switch would see + + align:start position:0% +switch because then the switch would see + + + align:start position:0% +switch because then the switch would see +two packets and then the congestion + + align:start position:0% +two packets and then the congestion + + + align:start position:0% +two packets and then the congestion +would not be one but two right so one + + align:start position:0% +would not be one but two right so one + + + align:start position:0% +would not be one but two right so one +and five also have an edge in + + align:start position:0% + + + + align:start position:0% + +between and in the same way we have two + + align:start position:0% +between and in the same way we have two + + + align:start position:0% +between and in the same way we have two +and six and seven and three so two and + + align:start position:0% +and six and seven and three so two and + + + align:start position:0% +and six and seven and three so two and +six + + align:start position:0% +six + + + align:start position:0% +six +are these is this this constraint like + + align:start position:0% +are these is this this constraint like + + + align:start position:0% +are these is this this constraint like +two and six over here and three and + + align:start position:0% +two and six over here and three and + + + align:start position:0% +two and six over here and three and +seven is the other constraint so if I + + align:start position:0% +seven is the other constraint so if I + + + align:start position:0% +seven is the other constraint so if I +have those constraints in + + align:start position:0% +have those constraints in + + + align:start position:0% +have those constraints in +place well then I know that um the + + align:start position:0% +place well then I know that um the + + + align:start position:0% +place well then I know that um the +routing that goes from Level zero to + + align:start position:0% +routing that goes from Level zero to + + + align:start position:0% +routing that goes from Level zero to +level one will not violate my congestion + + align:start position:0% +level one will not violate my congestion + + + align:start position:0% +level one will not violate my congestion +of one so that's great then I hope to be + + align:start position:0% +of one so that's great then I hope to be + + + align:start position:0% +of one so that's great then I hope to be +able to use the induction hypothesis and + + align:start position:0% +able to use the induction hypothesis and + + + align:start position:0% +able to use the induction hypothesis and +I get a proper routing within the red + + align:start position:0% +I get a proper routing within the red + + + align:start position:0% +I get a proper routing within the red +sub Network and one within the blue + + align:start position:0% +sub Network and one within the blue + + + align:start position:0% +sub Network and one within the blue +Network and then I need to map all these + + align:start position:0% +Network and then I need to map all these + + + align:start position:0% +Network and then I need to map all these +to these outputs so I also have + + align:start position:0% +to these outputs so I also have + + + align:start position:0% +to these outputs so I also have +constraints on these outputs because uh + + align:start position:0% +constraints on these outputs because uh + + + align:start position:0% +constraints on these outputs because uh +well for example take this particular + + align:start position:0% +well for example take this particular + + + align:start position:0% +well for example take this particular +switch it should not see a packet coming + + align:start position:0% +switch it should not see a packet coming + + + align:start position:0% +switch it should not see a packet coming +from this particular one and one from + + align:start position:0% +from this particular one and one from + + + align:start position:0% +from this particular one and one from +this one so how do I code that + + align:start position:0% +this one so how do I code that + + + align:start position:0% +this one so how do I code that +up + + align:start position:0% +up + + + align:start position:0% +up +so + + align:start position:0% +so + + + align:start position:0% +so +um okay so let me first write out what + + align:start position:0% +um okay so let me first write out what + + + align:start position:0% +um okay so let me first write out what +we did here and then we'll do the same + + align:start position:0% +we did here and then we'll do the same + + + align:start position:0% +we did here and then we'll do the same +for the last level over there + + align:start position:0% +for the last level over there + + + align:start position:0% +for the last level over there +so um oh no that's not really + + align:start position:0% +so um oh no that's not really + + + align:start position:0% +so um oh no that's not really +necessary + + align:start position:0% + + + + align:start position:0% + +um okay yeah so so at the output side + + align:start position:0% +um okay yeah so so at the output side + + + align:start position:0% +um okay yeah so so at the output side +over here we have similar constraints as + + align:start position:0% +over here we have similar constraints as + + + align:start position:0% +over here we have similar constraints as +we did over here and in this particular + + align:start position:0% +we did over here and in this particular + + + align:start position:0% +we did over here and in this particular +example just as an + + align:start position:0% +example just as an + + + align:start position:0% +example just as an +example um suppose we look at the packet + + align:start position:0% +example um suppose we look at the packet + + + align:start position:0% +example um suppose we look at the packet +that is uh + + align:start position:0% + + + + align:start position:0% + +destined for output + + align:start position:0% +destined for output + + + align:start position:0% +destined for output +zero well what is this packet well I + + align:start position:0% +zero well what is this packet well I + + + align:start position:0% +zero well what is this packet well I +know that Pi of 6 is equal to zero + + align:start position:0% +know that Pi of 6 is equal to zero + + + align:start position:0% +know that Pi of 6 is equal to zero +according to my example so packet six is + + align:start position:0% +according to my example so packet six is + + + align:start position:0% +according to my example so packet six is +destined for this particular output zero + + align:start position:0% +destined for this particular output zero + + + align:start position:0% +destined for this particular output zero +over here and comes goes through this + + align:start position:0% +over here and comes goes through this + + + align:start position:0% +over here and comes goes through this +particular + + align:start position:0% +particular + + + align:start position:0% +particular +switch so this packet + + align:start position:0% + + + + align:start position:0% + +um and + + align:start position:0% +um and + + + align:start position:0% +um and +also + + align:start position:0% + + + + align:start position:0% + +uh the + + align:start position:0% + + + + align:start position:0% + +packet for output + + align:start position:0% +packet for output + + + align:start position:0% +packet for output +four which is if you look at the mapping + + align:start position:0% +four which is if you look at the mapping + + + align:start position:0% +four which is if you look at the mapping +Pi of two is equal to four so that's + + align:start position:0% +Pi of two is equal to four so that's + + + align:start position:0% +Pi of two is equal to four so that's +packet number + + align:start position:0% +packet number + + + align:start position:0% +packet number +two well both of these packets cannot + + align:start position:0% +two well both of these packets cannot + + + align:start position:0% +two well both of these packets cannot +pass through the same sub + + align:start position:0% +pass through the same sub + + + align:start position:0% +pass through the same sub +Network cannot pass + + align:start position:0% + + + + align:start position:0% + +through the + + align:start position:0% +through the + + + align:start position:0% +through the +same sub Network so why is this so let's + + align:start position:0% +same sub Network so why is this so let's + + + align:start position:0% +same sub Network so why is this so let's +look at this particular example so + + align:start position:0% +look at this particular example so + + + align:start position:0% +look at this particular example so +output zero um well comes from uh packet + + align:start position:0% +output zero um well comes from uh packet + + + align:start position:0% +output zero um well comes from uh packet +six somewhere over there now suppose + + align:start position:0% +six somewhere over there now suppose + + + align:start position:0% +six somewhere over there now suppose +packet six was routed through the red + + align:start position:0% +packet six was routed through the red + + + align:start position:0% +packet six was routed through the red +Network + + align:start position:0% +Network + + + align:start position:0% +Network +and at the same moment also output four + + align:start position:0% +and at the same moment also output four + + + align:start position:0% +and at the same moment also output four +the packet that is destined for output + + align:start position:0% +the packet that is destined for output + + + align:start position:0% +the packet that is destined for output +four which is Packet number two suppose + + align:start position:0% +four which is Packet number two suppose + + + align:start position:0% +four which is Packet number two suppose +packet two was also going through the + + align:start position:0% +packet two was also going through the + + + align:start position:0% +packet two was also going through the +red + + align:start position:0% +red + + + align:start position:0% +red +Network + + align:start position:0% +Network + + + align:start position:0% +Network +well then I notice that both of these + + align:start position:0% +well then I notice that both of these + + + align:start position:0% +well then I notice that both of these +packets must arrive at this particular + + align:start position:0% +packets must arrive at this particular + + + align:start position:0% +packets must arrive at this particular +switch in order for one to be routed to + + align:start position:0% +switch in order for one to be routed to + + + align:start position:0% +switch in order for one to be routed to +Output zero and the other one to be + + align:start position:0% +Output zero and the other one to be + + + align:start position:0% +Output zero and the other one to be +routed to Output + + align:start position:0% +routed to Output + + + align:start position:0% +routed to Output +four so in order to avoid congestion in + + align:start position:0% +four so in order to avoid congestion in + + + align:start position:0% +four so in order to avoid congestion in +this particular switch over here we need + + align:start position:0% +this particular switch over here we need + + + align:start position:0% +this particular switch over here we need +to have a constraint the constraint says + + align:start position:0% +to have a constraint the constraint says + + + align:start position:0% +to have a constraint the constraint says +that the packet for two uh for packets + + align:start position:0% +that the packet for two uh for packets + + + align:start position:0% +that the packet for two uh for packets +two and six uh that those two cannot go + + align:start position:0% +two and six uh that those two cannot go + + + align:start position:0% +two and six uh that those two cannot go +through the same sub Network so we + + align:start position:0% +through the same sub Network so we + + + align:start position:0% +through the same sub Network so we +essentially have another Edge over here + + align:start position:0% +essentially have another Edge over here + + + align:start position:0% +essentially have another Edge over here +we already had the constr but uh but + + align:start position:0% +we already had the constr but uh but + + + align:start position:0% +we already had the constr but uh but +it's it's it's just the same Edge so + + align:start position:0% +it's it's it's just the same Edge so + + + align:start position:0% +it's it's it's just the same Edge so +let's look at the other + + align:start position:0% +let's look at the other + + + align:start position:0% +let's look at the other +um constraints that we have well for + + align:start position:0% +um constraints that we have well for + + + align:start position:0% +um constraints that we have well for +example + + align:start position:0% +example + + + align:start position:0% +example +um uh well let's uh look at a different + + align:start position:0% +um uh well let's uh look at a different + + + align:start position:0% +um uh well let's uh look at a different +example so for example um if I look at + + align:start position:0% +example so for example um if I look at + + + align:start position:0% +example so for example um if I look at +uh this switch well it can if if if if a + + align:start position:0% +uh this switch well it can if if if if a + + + align:start position:0% +uh this switch well it can if if if if a +packet goes through here that needs to + + align:start position:0% +packet goes through here that needs to + + + align:start position:0% +packet goes through here that needs to +end up at one and a packet that goes to + + align:start position:0% +end up at one and a packet that goes to + + + align:start position:0% +end up at one and a packet that goes to +five if those two packets are routed + + align:start position:0% +five if those two packets are routed + + + align:start position:0% +five if those two packets are routed +through the same red sub Network they + + align:start position:0% +through the same red sub Network they + + + align:start position:0% +through the same red sub Network they +have to end up here in order to go to + + align:start position:0% +have to end up here in order to go to + + + align:start position:0% +have to end up here in order to go to +both here and to there so have + + align:start position:0% +both here and to there so have + + + align:start position:0% +both here and to there so have +congestion of two so what are those + + align:start position:0% +congestion of two so what are those + + + align:start position:0% +congestion of two so what are those +packets well what does Pi map to two one + + align:start position:0% +packets well what does Pi map to two one + + + align:start position:0% +packets well what does Pi map to two one +and five let's so let's look over here + + align:start position:0% +and five let's so let's look over here + + + align:start position:0% +and five let's so let's look over here +we see that Pi uh uh zero is equal to 1 + + align:start position:0% +we see that Pi uh uh zero is equal to 1 + + + align:start position:0% +we see that Pi uh uh zero is equal to 1 +and Pi uh 1 is equal to 5 so packet zero + + align:start position:0% +and Pi uh 1 is equal to 5 so packet zero + + + align:start position:0% +and Pi uh 1 is equal to 5 so packet zero +and one are actually mapped to Output uh + + align:start position:0% +and one are actually mapped to Output uh + + + align:start position:0% +and one are actually mapped to Output uh +one and five and they should not go both + + align:start position:0% +one and five and they should not go both + + + align:start position:0% +one and five and they should not go both +through the same sub + + align:start position:0% +through the same sub + + + align:start position:0% +through the same sub +Network okay so we have another Edge + + align:start position:0% +Network okay so we have another Edge + + + align:start position:0% +Network okay so we have another Edge +over here and now we can continue this + + align:start position:0% +over here and now we can continue this + + + align:start position:0% +over here and now we can continue this +and we have five and seven so just have + + align:start position:0% +and we have five and seven so just have + + + align:start position:0% +and we have five and seven so just have +a look over there say five and seven + + align:start position:0% +a look over there say five and seven + + + align:start position:0% +a look over there say five and seven +they map to the outputs two and six + + align:start position:0% +they map to the outputs two and six + + + align:start position:0% +they map to the outputs two and six +again we have two and six if they are + + align:start position:0% +again we have two and six if they are + + + align:start position:0% +again we have two and six if they are +both mapped to the same network this one + + align:start position:0% +both mapped to the same network this one + + + align:start position:0% +both mapped to the same network this one +for + + align:start position:0% +for + + + align:start position:0% +for +example uh then I will have a + + align:start position:0% +example uh then I will have a + + + align:start position:0% +example uh then I will have a +problem um Okay so + + align:start position:0% +problem um Okay so + + + align:start position:0% +problem um Okay so +the other Edge is over + + align:start position:0% +the other Edge is over + + + align:start position:0% +the other Edge is over +here okay so what did we do here we + + align:start position:0% +here okay so what did we do here we + + + align:start position:0% +here okay so what did we do here we +started to write out the constraints on + + align:start position:0% +started to write out the constraints on + + + align:start position:0% +started to write out the constraints on +this side and we wrote out the + + align:start position:0% +this side and we wrote out the + + + align:start position:0% +this side and we wrote out the +constraints on this side um uh so I only + + align:start position:0% +constraints on this side um uh so I only + + + align:start position:0% +constraints on this side um uh so I only +looked at the red sub Network that's + + align:start position:0% +looked at the red sub Network that's + + + align:start position:0% +looked at the red sub Network that's +what I realized now I could also have + + align:start position:0% +what I realized now I could also have + + + align:start position:0% +what I realized now I could also have +looked at the blue Network so let's do + + align:start position:0% +looked at the blue Network so let's do + + + align:start position:0% +looked at the blue Network so let's do +that also just to make the picture + + align:start position:0% +that also just to make the picture + + + align:start position:0% +that also just to make the picture +complete so for example let's look at uh + + align:start position:0% +complete so for example let's look at uh + + + align:start position:0% +complete so for example let's look at uh +this particular example the packet six + + align:start position:0% +this particular example the packet six + + + align:start position:0% +this particular example the packet six +and two should not both be routed + + align:start position:0% +and two should not both be routed + + + align:start position:0% +and two should not both be routed +through the blue Network because then + + align:start position:0% +through the blue Network because then + + + align:start position:0% +through the blue Network because then +they would both have to go through this + + align:start position:0% +they would both have to go through this + + + align:start position:0% +they would both have to go through this +switch one going up to Output zero and + + align:start position:0% +switch one going up to Output zero and + + + align:start position:0% +switch one going up to Output zero and +one going to the left to the right to + + align:start position:0% +one going to the left to the right to + + + align:start position:0% +one going to the left to the right to +Output + + align:start position:0% +Output + + + align:start position:0% +Output +four so to in order to avoid congestion + + align:start position:0% +four so to in order to avoid congestion + + + align:start position:0% +four so to in order to avoid congestion +at all at all costs we have this + + align:start position:0% +at all at all costs we have this + + + align:start position:0% +at all at all costs we have this +constraint graph so now we come to the + + align:start position:0% +constraint graph so now we come to the + + + align:start position:0% +constraint graph so now we come to the +key inside and the key inside is to use + + align:start position:0% +key inside and the key inside is to use + + + align:start position:0% +key inside and the key inside is to use +a two coloring of this of this graph + + align:start position:0% + + + + align:start position:0% + +so the key + + align:start position:0% +so the key + + + align:start position:0% +so the key +inside is a two + + align:start position:0% + + + + align:start position:0% + +coloring of the constrainted + + align:start position:0% + + + + align:start position:0% + +graph which will lead to a uh best + + align:start position:0% +graph which will lead to a uh best + + + align:start position:0% +graph which will lead to a uh best +solution for the routing + + align:start position:0% +solution for the routing + + + align:start position:0% +solution for the routing +problem okay so let's uh do this so we + + align:start position:0% +problem okay so let's uh do this so we + + + align:start position:0% +problem okay so let's uh do this so we +will color this one blue as you can see + + align:start position:0% +will color this one blue as you can see + + + align:start position:0% +will color this one blue as you can see +this is an even + + align:start position:0% +this is an even + + + align:start position:0% +this is an even +cycle uh blue + + align:start position:0% +cycle uh blue + + + align:start position:0% +cycle uh blue +red blue + + align:start position:0% +red blue + + + align:start position:0% +red blue +red um blue and red we'll make this one + + align:start position:0% +red um blue and red we'll make this one + + + align:start position:0% +red um blue and red we'll make this one +blue and this one + + align:start position:0% +blue and this one + + + align:start position:0% +blue and this one +red well it turns out that we can now + + align:start position:0% +red well it turns out that we can now + + + align:start position:0% +red well it turns out that we can now +start our routing process um so for + + align:start position:0% +start our routing process um so for + + + align:start position:0% +start our routing process um so for +example um actually I will draw a new + + align:start position:0% +example um actually I will draw a new + + + align:start position:0% +example um actually I will draw a new +graph to make that really clear + + align:start position:0% + + + + align:start position:0% + +um so I have my blue and my red chalk + + align:start position:0% +um so I have my blue and my red chalk + + + align:start position:0% +um so I have my blue and my red chalk +over here to demonstrate what I mean + + align:start position:0% +over here to demonstrate what I mean + + + align:start position:0% +over here to demonstrate what I mean +um so what I do I do I have zero 1 2 3 4 + + align:start position:0% +um so what I do I do I have zero 1 2 3 4 + + + align:start position:0% +um so what I do I do I have zero 1 2 3 4 +five six and + + align:start position:0% +five six and + + + align:start position:0% +five six and +seven I have the switches that + + align:start position:0% +seven I have the switches that + + + align:start position:0% +seven I have the switches that +correspond to those + + align:start position:0% + + + + align:start position:0% + +um well if it's colored uh uh red uh so + + align:start position:0% +um well if it's colored uh uh red uh so + + + align:start position:0% +um well if it's colored uh uh red uh so +zero over here is colored red I will + + align:start position:0% +zero over here is colored red I will + + + align:start position:0% +zero over here is colored red I will +direct it to the red sub Network so + + align:start position:0% +direct it to the red sub Network so + + + align:start position:0% +direct it to the red sub Network so +where is this red sub + + align:start position:0% +where is this red sub + + + align:start position:0% +where is this red sub +Network it's really + + align:start position:0% +Network it's really + + + align:start position:0% +Network it's really +contained over + + align:start position:0% + + + + align:start position:0% + +here and the blue + + align:start position:0% +here and the blue + + + align:start position:0% +here and the blue +one so this is the red + + align:start position:0% +one so this is the red + + + align:start position:0% +one so this is the red +one and the blue one is right here + + align:start position:0% + + + + align:start position:0% + +and over here we have the + + align:start position:0% + + + + align:start position:0% + +outputs ranging from 0 one two all the + + align:start position:0% +outputs ranging from 0 one two all the + + + align:start position:0% +outputs ranging from 0 one two all the +way + + align:start position:0% +way + + + align:start position:0% +way +27 okay so input zero is colored red we + + align:start position:0% +27 okay so input zero is colored red we + + + align:start position:0% +27 okay so input zero is colored red we +go straight ahead we want to go to the + + align:start position:0% +go straight ahead we want to go to the + + + align:start position:0% +go straight ahead we want to go to the +red Network input one is colored blue it + + align:start position:0% +red Network input one is colored blue it + + + align:start position:0% +red Network input one is colored blue it +goes therefore + + align:start position:0% +goes therefore + + + align:start position:0% +goes therefore +to the blue Network so this is the only + + align:start position:0% +to the blue Network so this is the only + + + align:start position:0% +to the blue Network so this is the only +way how to do it input two is calleded + + align:start position:0% +way how to do it input two is calleded + + + align:start position:0% +way how to do it input two is calleded +red go straight ahead input three is + + align:start position:0% +red go straight ahead input three is + + + align:start position:0% +red go straight ahead input three is +also colored red go straight ahead input + + align:start position:0% +also colored red go straight ahead input + + + align:start position:0% +also colored red go straight ahead input +five oh input + + align:start position:0% +five oh input + + + align:start position:0% +five oh input +four is color blue goes to the blue + + align:start position:0% +four is color blue goes to the blue + + + align:start position:0% +four is color blue goes to the blue +Network input five goes up to the red + + align:start position:0% +Network input five goes up to the red + + + align:start position:0% +Network input five goes up to the red +Network and input six goes straight + + align:start position:0% +Network and input six goes straight + + + align:start position:0% +Network and input six goes straight +ahead to the blue network is called it + + align:start position:0% +ahead to the blue network is called it + + + align:start position:0% +ahead to the blue network is called it +blue input seven is also color + + align:start position:0% +blue input seven is also color + + + align:start position:0% +blue input seven is also color +blue okay let's look at the outputs so + + align:start position:0% +blue okay let's look at the outputs so + + + align:start position:0% +blue okay let's look at the outputs so +for example um well let's have a look at + + align:start position:0% +for example um well let's have a look at + + + align:start position:0% +for example um well let's have a look at +uh output + + align:start position:0% +uh output + + + align:start position:0% +uh output +zero + + align:start position:0% +zero + + + align:start position:0% +zero +um so output + + align:start position:0% +um so output + + + align:start position:0% +um so output +zero um which packet is mapped to Output + + align:start position:0% +zero um which packet is mapped to Output + + + align:start position:0% +zero um which packet is mapped to Output +zero it's a packet number uh + + align:start position:0% +zero it's a packet number uh + + + align:start position:0% +zero it's a packet number uh +six so six was mapped Into the Blue + + align:start position:0% +six so six was mapped Into the Blue + + + align:start position:0% +six so six was mapped Into the Blue +Network and then it needs to be mapped + + align:start position:0% +Network and then it needs to be mapped + + + align:start position:0% +Network and then it needs to be mapped +to uh output zero so it's only one Edge + + align:start position:0% +to uh output zero so it's only one Edge + + + align:start position:0% +to uh output zero so it's only one Edge +that goes from the blue Network to + + align:start position:0% +that goes from the blue Network to + + + align:start position:0% +that goes from the blue Network to +Output zero which is uh this particular + + align:start position:0% +Output zero which is uh this particular + + + align:start position:0% +Output zero which is uh this particular +one and then somehow this one needs to + + align:start position:0% +one and then somehow this one needs to + + + align:start position:0% +one and then somehow this one needs to +be mapped to this one over here now we + + align:start position:0% +be mapped to this one over here now we + + + align:start position:0% +be mapped to this one over here now we +can continue like this um output one + + align:start position:0% +can continue like this um output one + + + align:start position:0% +can continue like this um output one +should receive a packet from let's look + + align:start position:0% +should receive a packet from let's look + + + align:start position:0% +should receive a packet from let's look +at the permutation from five so uh no + + align:start position:0% +at the permutation from five so uh no + + + align:start position:0% +at the permutation from five so uh no +sorry output one uh Pi of0 is equal to + + align:start position:0% +sorry output one uh Pi of0 is equal to + + + align:start position:0% +sorry output one uh Pi of0 is equal to +one one so packet zero needs to go to + + align:start position:0% +one one so packet zero needs to go to + + + align:start position:0% +one one so packet zero needs to go to +this particular output now P packet zero + + align:start position:0% +this particular output now P packet zero + + + align:start position:0% +this particular output now P packet zero +is in the red Network so it's only one + + align:start position:0% +is in the red Network so it's only one + + + align:start position:0% +is in the red Network so it's only one +Edge that goes from the red Network to + + align:start position:0% +Edge that goes from the red Network to + + + align:start position:0% +Edge that goes from the red Network to +this output so we need to have + + align:start position:0% +this output so we need to have + + + align:start position:0% +this output so we need to have +connection over here now we can continue + + align:start position:0% +connection over here now we can continue + + + align:start position:0% +connection over here now we can continue +this and Note and and demonstrate and + + align:start position:0% +this and Note and and demonstrate and + + + align:start position:0% +this and Note and and demonstrate and +you can test it for yourself too that + + align:start position:0% +you can test it for yourself too that + + + align:start position:0% +you can test it for yourself too that +output four needs to receive a packet + + align:start position:0% +output four needs to receive a packet + + + align:start position:0% +output four needs to receive a packet +from the red Network actually it should + + align:start position:0% +from the red Network actually it should + + + align:start position:0% +from the red Network actually it should +be this particular one which happens to + + align:start position:0% +be this particular one which happens to + + + align:start position:0% +be this particular one which happens to +be packet number + + align:start position:0% +be packet number + + + align:start position:0% +be packet number +two and then we have this one uh + + align:start position:0% +two and then we have this one uh + + + align:start position:0% +two and then we have this one uh +right so let me just finish it we have + + align:start position:0% +right so let me just finish it we have + + + align:start position:0% +right so let me just finish it we have +this and we have uh these + + align:start position:0% +this and we have uh these + + + align:start position:0% +this and we have uh these +two and we + + align:start position:0% +two and we + + + align:start position:0% +two and we +have this + + align:start position:0% +have this + + + align:start position:0% +have this +one we have this one and we have this + + align:start position:0% +one we have this one and we have this + + + align:start position:0% +one we have this one and we have this +one this one goes Straight + + align:start position:0% +one this one goes Straight + + + align:start position:0% +one this one goes Straight +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +Ahead uh this one goes all the way up + + align:start position:0% +Ahead uh this one goes all the way up + + + align:start position:0% +Ahead uh this one goes all the way up +and this one goes all the way up so what + + align:start position:0% +and this one goes all the way up so what + + + align:start position:0% +and this one goes all the way up so what +do we see we see that packets over + + align:start position:0% +do we see we see that packets over + + + align:start position:0% +do we see we see that packets over +here that these switch switches only see + + align:start position:0% +here that these switch switches only see + + + align:start position:0% +here that these switch switches only see +a packet once and these ones as well + + align:start position:0% +a packet once and these ones as well + + + align:start position:0% +a packet once and these ones as well +this one also and these ones also + + align:start position:0% +this one also and these ones also + + + align:start position:0% +this one also and these ones also +so um we have directed the packets + + align:start position:0% +so um we have directed the packets + + + align:start position:0% +so um we have directed the packets +routed the packets to the red and the + + align:start position:0% +routed the packets to the red and the + + + align:start position:0% +routed the packets to the red and the +blue sub networks in such a way that the + + align:start position:0% +blue sub networks in such a way that the + + + align:start position:0% +blue sub networks in such a way that the +congestion at the uh at at the last + + align:start position:0% +congestion at the uh at at the last + + + align:start position:0% +congestion at the uh at at the last +level and at the first level is still + + align:start position:0% +level and at the first level is still + + + align:start position:0% +level and at the first level is still +equal to one now we use our induction + + align:start position:0% +equal to one now we use our induction + + + align:start position:0% +equal to one now we use our induction +hypothesis and we conclude that we can + + align:start position:0% +hypothesis and we conclude that we can + + + align:start position:0% +hypothesis and we conclude that we can +map uh the route that we can have a + + align:start position:0% +map uh the route that we can have a + + + align:start position:0% +map uh the route that we can have a +routing from packets from here to here + + align:start position:0% +routing from packets from here to here + + + align:start position:0% +routing from packets from here to here +such that the congestion within the sub + + align:start position:0% +such that the congestion within the sub + + + align:start position:0% +such that the congestion within the sub +networks is only one so within the blue + + align:start position:0% +networks is only one so within the blue + + + align:start position:0% +networks is only one so within the blue +as well as in the + + align:start position:0% +as well as in the + + + align:start position:0% +as well as in the +red so this is the insight into how this + + align:start position:0% +red so this is the insight into how this + + + align:start position:0% +red so this is the insight into how this +works and and I notice I'm running out + + align:start position:0% +works and and I notice I'm running out + + + align:start position:0% +works and and I notice I'm running out +of time so the formal proof we will have + + align:start position:0% +of time so the formal proof we will have + + + align:start position:0% +of time so the formal proof we will have +to postpone till + + align:start position:0% +to postpone till + + + align:start position:0% +to postpone till +recitation but uh that's actually really + + align:start position:0% +recitation but uh that's actually really + + + align:start position:0% +recitation but uh that's actually really +a very simple thing to do that right now + + align:start position:0% +a very simple thing to do that right now + + + align:start position:0% +a very simple thing to do that right now +to just keep this key inside and then uh + + align:start position:0% +to just keep this key inside and then uh + + + align:start position:0% +to just keep this key inside and then uh +you can easily uh prove the + + align:start position:0% +you can easily uh prove the + + + align:start position:0% +you can easily uh prove the +theorem so but this is the real the real + + align:start position:0% +theorem so but this is the real the real + + + align:start position:0% +theorem so but this is the real the real +insight thank you \ No newline at end of file diff --git a/blBcCjIY7Sg.txt b/blBcCjIY7Sg.txt new file mode 100644 index 0000000000000000000000000000000000000000..9921eccadb69e3e97d988d54c73272f9d0f9bc5a --- /dev/null +++ b/blBcCjIY7Sg.txt @@ -0,0 +1,487 @@ +Good morning. Good morning. Today I'm going to talk about, + +this is lecture 14, and I'm going to talk about protein localization. + +Now, some of you may remember that earlier in the semester I was + +walking around with this sling. And so to help me from writing on + +the board, even though it is this arm, I have made a PowerPoint + +presentation of most of the things that I would have written + +on the board. And for your ease and comfort, + +this PowerPoint presentation will be posted online so you won't have to + +write down everything in my slides. So just sort of sit back. And I + +will write a few things on the board, so you can write those down. + +OK. So now you guys have heard about central dogma from Professor + +Eric Lander and you've heard about gene regulation last Friday. + +Here is something that you're familiar with, + +this image here depicting central dogma. + +DNA replicates to DNA. This is replication. Replication. + +DNA is translated, excuse me, transcribed to RNA. + +Transcription. And RNA is translated to protein. + +Central dogma. Where does this occur? Where does replication + +occur in a cell? Nucleus. Good. + +Where does transcription occur in a cell? Nucleus. + +I heard nucleus. That is correct. And where does + +translation occur? Cytoplasm. Ah, and yet we know + +that these processes require proteins to do them. + +OK. You've just described where these processes occur in a + +eukaryotic cell. Let's say you're a bacterium. + +In bacteria, where does replication, transcription and translation occur? + +Where? Cytoplasm. OK. So now we've made bacteria look very + +simple. But they're not that simple. And so let's take a look here. + +Here's a bacterial cell. I've drawn what could be E. + +coli. I has an outer membrane, an inner membrane, and the space in + +between is the perisplasm. Now, here is its circular + +chromosome. I've transcribed some gene to an RNA and a ribosomal pop + +on and make a protein which his in the cytoplasm. + +Yet some proteins are localized to the inner membrane, + +others are localized to the periplasm, and some are localized to + +the outer membrane, and others are actually exported + +completely outside the cell. Even more complicated is a + +eukaryotic protein, because not only does it have a + +plasma membrane where proteins are localized. It has a bunch + +of organelles. There's the nucleus and there's + +mitochondria and there's endoplasmic reticulum and Golgi apparatus. + +And it, too, translates RNA by ribosomes in the cytoplasm. + +So how do these proteins get back to the nucleus or go into the + +mitochondria or get into the organelles? So what we're going to + +do in the next few slides is we're going to follow the process, + +because they're so similar in bacteria and eukaryotic cells, + +of how proteins get to the membrane and how they get outside the cell. + +And then I'll go back and talk about how proteins get into some of the + +organelles. So let me show you what some of the proteins are. + +So an example of a cytoplasmic protein in bacteria is beta + +galactosidase. You've heard about it. + +It breaks down lactose. It's in the cytoplasm. And example + +of a membrane protein is a lactose receptor. + +The lacY permease that's on the surface of the cell brings lactose + +in. An example of a fully secreted protein is a toxin. + +For instance, bacillus anthracis makes anthrax toxin. + +It's completely exported from the cell. In a eukaryotic cell there's + +a bunch of cytoplasmic proteins. There are all of the glycolytic + +enzymes. And, for instance, biosynthetic amino + +acid enzymes like histidine synthesis enzymes, those + +are cytoplasmic. For a membrane protein there are + +receptors, like the receptor for insulin, a hormone, + +a peptide hormone, or growth factor receptors, every receptor that's + +membrane-bound. And a fully secreted protein. + +Some cells like pancreatic cells secrete insulin. + +Some cells like some of your immune cells secrete antibodies. + +OK. So it was not clear how these cytoplasmically made proteins, + +proteins that were made in the cytoplasm got to this location. + +And the person who worked on this was George Palade. + +And this was in the fifties. And he studied pancreatic cells + +because they're master secretors. And he was able to perfect his + +microscopic technique. And you can see here this is a + +pancreatic cell. This is endoplasmic reticulum + +studded with ribosomes. These are mitochondria. + +This is the nucleus. Here is another picture that he took. + +And here is the rough endoplasmic reticulum studded with ribosomes. + +Here's Golgi apparatus. And then there are like little vesicles. + +So he did this experiment where he decided he would pulse label + +proteins as they were being synthesized in a pancreas, + +directly in a pancreas. So what he did was he injected + +radioactive amino acids directly into the pancreas of hamsters. + + I guess I could draw a little + +hamster here. And he directly injected radioactive isotopes. + +And what he's doing is these radioactive amino acids will be + +incorporated into proteins as they're being translated, + +and he can follow the population of freshly translated proteins through + +the cell. So he injects hamsters with the radioactive amino acids. + +And then at various time points he adds, he also injects glutaraldehyde. + +So first the label, then glutaraldehyde. And what this + +does is it fixes the cells in its tracks. Whatever the cell is doing + +it just stops. And he removes the pancreas and he + +looks at the cells. This is fixes the cells. + +So, Tom, I don't know what's going on here. Can we not use this, + +Tom? All right. It's just doing it on its own. It has some time thing? + +Oh. All right. So what he found was at the early time points, + +now, what I did, I did this, OK? He didn't see yellow. What I did + +was I added yellow to his original slide to show you at the earliest + +time point he found the label associated with the endoplasmic + +reticulum. At the next time point he found the + +label associated with the Golgi apparatus. And then at even later + +time points he found the label in secretory vesicles. + +So this is my representation of what he found. + +So here's a cell, nucleus, mitochondria. + +The early time points the label was in the ER followed by the Golgi. + +I didn't do that. Yeah, take it out. + +Followed by vesicles. It's not working. OK. + +Sorry for that. I'm sorry. So he won a Nobel Prize for this + +work because it is the pathway that still holds true today. + +Now, he won the Nobel Prize in '74. And at about that time, maybe '71, + +another scientist names Cesar Milstein was working on immunology. + +And what he did was he fused a cancer cell with a cell that + +constantly secreted antibodies, so he ended up having an + +immortalized antibody producing cell. And he was doing some research and + +he did in vitro analysis. And he found that antibodies that + +were produced in vitro were longer than the ones that were actually + +coming out of the cell. So he proposed that there was an + +N-terminal end. He looked and saw that the + +N-terminus was different, and he proposed that it would + +possibly be cleaved upon export. OK? And so this is, he won a Nobel + +Prize, not for this work but for his work in immunology. + +And this was also correct. And so this is from his lecture, + +Nobel lecture. It says in vitro synthesis of immunoglobulin light + +chains, that's what he was doing, to our delight we ran into the + +unexpected observation of the existence of a biosynthetic + +precursor of light chain. Further experiments led us to + +propose the extra N-terminal sequence was a signal for vectorial + +transport across the membrane during protein synthesis. + +This was the first evidence that indicated the signal for secretion + +was an N-terminal segment rapidly cleaved upon protein synthesis. + +OK. So now there was a student of Palade. He was a post-doctoral + +student. His name was Guther Blobel. + +And he saw this experiment in 1971. And he thought how do we know it's + +not an artifact of in vitro science? Well, how do you know that the + +ribosomes are not just hoping on earlier in the message? + +Maybe that's why it's a longer protein. And he didn't buy it. + +So he wanted to further pursue this. And he did it in the + +Palade manner. So what he did was he took a test + +tube and he added message for exported protein, + +ribosomes and charged tRNAs. And when I say charged tRNAs I mean + +tRNAs that have amino acids attached to them. And so if you add those + +three things to a test tube you find a protein is made. So then + +he added microsomes. What are microsomes? + +OK. We're going to pause this. + +Now, I told you what Palade found out. He found out that proteins + +were first seen in the rough ER in the lumen. This is the lumen right + +here. This is where he first observed radioactivity. + +Now, if you take endoplasmic reticulum and you share it, + +it forms little tiny vesicles, little vesicles with ribosomes on + +the outside. And they're called microsomes for + +small things. Microsomes. And they're essentially little + +rough endoplasmic reticulum vesicles. So when Blobel added to the same + +test tube that had the RNA, the ribosomes, the tRNA. + +When he added microsomes he found that the protein was still in the + +supernatant. There was no protein found in the lumen of the microsomes. + +So he figured, OK, it needs something. + +Let me go extract something from the cytoplasm. + +And he extracted lots of fractions. And he added these cytoplasmic + +fractions. And he found that one faction actually was able to cause + +the peptide to enter the microsome. And if he added this fraction late + +in the reaction, the protein would never get into the + +lumen of the microsome. But if he added the fraction late, + +I mean, excuse me, early, if he added the faction early they would + +get in. So let me just summarize. So message ribosomes, tRNA, you + +find protein in the supernatant. Message ribosomes, tRNAs, plus + +microsomes, protein in the supernatant, not in the microsomes. + +You add a fraction that works sometimes, but if it's added late + +the protein is in the supernatant. But if you add that fraction early + +the protein is in the lumen of the microsomes. So he interpreted this + +result as that there was an amino acid sequence at the beginning of an + +exported protein. And that's recognized by a complex + +that was in the fraction. This complex is required to get the + +protein to the lumen of the ER. And to get to the lumen of the ER + +the protein has to be just beginning to be translated. + +Now, since not all proteins have the same N-terminus, + +Blobel predicated, like Milstein, whatever the sequence was it would + +later be cleaved. And he won a Nobel Prize for this + +in 1999. And it wasn't just for this, because he went on and he + +actually figured out the entire pathway. + +In the next few slides I'm going to show you what he discerned. + +One thing I want to just point out, though, the experiment he did was + +heterologous. So the extract came from wheat germ, + +the microsomes came from dog, and yet it still worked. And it was + +right because this pathway is universal. And let me show you how + +universal. It's used in bacteria and it's used in eukaryotic cells. + +So here's a bacterium, it's translating a message. + +Here's the signal starting to be translated, it's an exported protein. + +The same thing, in the cytoplasm a signal sequence + +is being newly made. And here's a close look of the + +signal sequence. It's about 20 amino acids long. + +It has a couple of positive charges at its extreme N-terminus. + +In the middle there's about seven to twelve hydrophobic amino acids + +variable. And this called a signal sequence. OK, + +so let's take a look at what happens. OK. Now we're in the cytoplasm of + +a eukaryotic cell. Here is a signal sequence emerging + +from a ribosome here. What recognizes it is SRP. + +That's what he named his complex for signal recognition particle. + +So SRP binds to the signal sequence. And, if you recall, it takes it to + +the ER to be translated. Here's a picture of the ER. + +And there's a docking protein or SRP receptor. So the SRP binds to + +the docking protein, it brings with it the signal + +sequence which is attached to the ribosome, which is attached to the + +message. Adjacent to the docking protein is a translocon which is a + +channel composed of proteins. The ribosome pops onto the + +translocon. The SRP floats away. And notice that the signal sequence + +is in the membrane, excuse me, starts to enter through + +the membrane and translation resumes. + +The signal sequence is cleaved by a signal peptidase within the ER, + +it cleaves off the signal and translation continues. + +And if it's a fully secreted protein it's fully internalized + +within the lumen of the ER and the ribosome pops up. + +If it's a membrane protein the signal is cleaved again, + +translation resumes, and then it gets imbedded in the membrane. + +And so I'm going to shut this off, otherwise it's going to keep going + +on its own here. So if it's a membrane protein what + +does it have? It has a transmembrane stretch. + +You've seen this maybe before in problem sets. So it's a + +transmembrane stretch. + +Or transmembrane domain. It's about 20, 22 amino acids long. + +It can be 30 maybe. So we'll say 20 to 25 amino acids of + +hydrophobic residues. + +It is a stop transfer sequence. Stop transfer for going across an + +ER membrane. It anchors it in the membrane. + + It forms alpha helix. + + If this part is the lumen of the ER + +right in here then this is the cytoplasm. + + OK. So that's how membranes and + +proteins look of this kind. Now, as you can see here, + +it's in the membrane. It's imbedded in the membrane. + +And I've drawn a different membrane protein over here because this + +protein is going to work its way to the far side of the endoplasmic + +reticulum. OK? As the fully secreted protein will + +also work its way. In the endoplasmic reticulum sugars + +get put on these proteins. So when they get to the far side + +they bleb off into little transport vesicles. + +OK? So here's the cytoplasmic protein completely within the lumen + +of the vesicle. Here's the membrane protein + +imbedded in the membrane of the vesicle. And if you remember Palade + +sequence, the next stop is the Golgi. So the head over to the Golgi, + +they bind, they fuse, and what was imbedded in the membrane is still + +imbedded in the membrane. And the fully secreted protein is + +within the lumen of the Golgi. Here the sugars are modified. I + +put little bows on them. And they work there way over to the + +far side of the Golgi where they bleb off again into + +secretory vesicles. \ No newline at end of file diff --git a/cEoteBfcBE0.txt b/cEoteBfcBE0.txt new file mode 100644 index 0000000000000000000000000000000000000000..ed62eefd4a617640ba9e2cdcaea63ae550a3a179 --- /dev/null +++ b/cEoteBfcBE0.txt @@ -0,0 +1,3763 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT OpenCourseWare continue to + + align:start position:0% +will help MIT OpenCourseWare continue to + + + align:start position:0% +will help MIT OpenCourseWare continue to +offer high quality educational resources + + align:start position:0% +offer high quality educational resources + + + align:start position:0% +offer high quality educational resources +for free + + align:start position:0% +for free + + + align:start position:0% +for free +to make a donation or view additional + + align:start position:0% +to make a donation or view additional + + + align:start position:0% +to make a donation or view additional +materials from hundreds of MIT courses + + align:start position:0% +materials from hundreds of MIT courses + + + align:start position:0% +materials from hundreds of MIT courses +visit MIT opencourseware at ocw.mit.edu + + align:start position:0% +visit MIT opencourseware at ocw.mit.edu + + + align:start position:0% +visit MIT opencourseware at ocw.mit.edu +we're now on story board 12 session 13 + + align:start position:0% +we're now on story board 12 session 13 + + + align:start position:0% +we're now on story board 12 session 13 +let's take a look first at panel a I + + align:start position:0% +let's take a look first at panel a I + + + align:start position:0% +let's take a look first at panel a I +mentioned earlier that respiration is + + align:start position:0% +mentioned earlier that respiration is + + + align:start position:0% +mentioned earlier that respiration is +the oxidative metabolism of all + + align:start position:0% +the oxidative metabolism of all + + + align:start position:0% +the oxidative metabolism of all +metabolic fuels carbohydrates as well as + + align:start position:0% +metabolic fuels carbohydrates as well as + + + align:start position:0% +metabolic fuels carbohydrates as well as +lipids if we were starting with a + + align:start position:0% +lipids if we were starting with a + + + align:start position:0% +lipids if we were starting with a +carbohydrate than respiration starts + + align:start position:0% +carbohydrate than respiration starts + + + align:start position:0% +carbohydrate than respiration starts +with the pyruvate dehydrogenase reaction + + align:start position:0% +with the pyruvate dehydrogenase reaction + + + align:start position:0% +with the pyruvate dehydrogenase reaction +and then proceeds into the TCA cycle and + + align:start position:0% +and then proceeds into the TCA cycle and + + + align:start position:0% +and then proceeds into the TCA cycle and +then into electron transport and + + align:start position:0% +then into electron transport and + + + align:start position:0% +then into electron transport and +oxidative phosphorylation + + align:start position:0% +oxidative phosphorylation + + + align:start position:0% +oxidative phosphorylation +if the acetyl co a comes from fatty acid + + align:start position:0% +if the acetyl co a comes from fatty acid + + + align:start position:0% +if the acetyl co a comes from fatty acid +oxidation which we'll cover later that + + align:start position:0% +oxidation which we'll cover later that + + + align:start position:0% +oxidation which we'll cover later that +we do not have to do the pyruvate + + align:start position:0% +we do not have to do the pyruvate + + + align:start position:0% +we do not have to do the pyruvate +dehydrogenase step three molecules of + + align:start position:0% +dehydrogenase step three molecules of + + + align:start position:0% +dehydrogenase step three molecules of +NADH and one molecule of fadh2 are + + align:start position:0% +NADH and one molecule of fadh2 are + + + align:start position:0% +NADH and one molecule of fadh2 are +produced as the carriers of electrons + + align:start position:0% +produced as the carriers of electrons + + + align:start position:0% +produced as the carriers of electrons +from the intermediates in the TCA cycle + + align:start position:0% +from the intermediates in the TCA cycle + + + align:start position:0% +from the intermediates in the TCA cycle +from each input molecule of acetyl + + align:start position:0% +from each input molecule of acetyl + + + align:start position:0% +from each input molecule of acetyl +coenzyme a as I mentioned a number of + + align:start position:0% +coenzyme a as I mentioned a number of + + + align:start position:0% +coenzyme a as I mentioned a number of +times we look at nadh and fadh2 is + + align:start position:0% +times we look at nadh and fadh2 is + + + align:start position:0% +times we look at nadh and fadh2 is +relatively mobile electron carriers + + align:start position:0% +relatively mobile electron carriers + + + align:start position:0% +relatively mobile electron carriers +they're going to be picking up electrons + + align:start position:0% +they're going to be picking up electrons + + + align:start position:0% +they're going to be picking up electrons +from intermediates and biochemical + + align:start position:0% +from intermediates and biochemical + + + align:start position:0% +from intermediates and biochemical +pathways and then they bring those + + align:start position:0% +pathways and then they bring those + + + align:start position:0% +pathways and then they bring those +electrons into the mitochondrial inner + + align:start position:0% +electrons into the mitochondrial inner + + + align:start position:0% +electrons into the mitochondrial inner +membrane where the reducing equivalents + + align:start position:0% +membrane where the reducing equivalents + + + align:start position:0% +membrane where the reducing equivalents +are passed along to the electron + + align:start position:0% +are passed along to the electron + + + align:start position:0% +are passed along to the electron +transport chain ultimately the electrons + + align:start position:0% +transport chain ultimately the electrons + + + align:start position:0% +transport chain ultimately the electrons +will end up being deposited into oxygen + + align:start position:0% +will end up being deposited into oxygen + + + align:start position:0% +will end up being deposited into oxygen +to make water let's turn to panel B + + align:start position:0% +to make water let's turn to panel B + + + align:start position:0% +to make water let's turn to panel B +where I'm going to start laying out the + + align:start position:0% +where I'm going to start laying out the + + + align:start position:0% +where I'm going to start laying out the +big picture in this small cartoon we see + + align:start position:0% +big picture in this small cartoon we see + + + align:start position:0% +big picture in this small cartoon we see +fuel being oxidized to carbon dioxide + + align:start position:0% +fuel being oxidized to carbon dioxide + + + align:start position:0% +fuel being oxidized to carbon dioxide +the electrons are passed to either nad + + align:start position:0% +the electrons are passed to either nad + + + align:start position:0% +the electrons are passed to either nad +plus or fa d to form the reduced + + align:start position:0% +plus or fa d to form the reduced + + + align:start position:0% +plus or fa d to form the reduced +cofactor the reduced cofactors find + + align:start position:0% +cofactor the reduced cofactors find + + + align:start position:0% +cofactor the reduced cofactors find +their way to the mitochondrial inner + + align:start position:0% +their way to the mitochondrial inner + + + align:start position:0% +their way to the mitochondrial inner +membrane and the electrons are reducing + + align:start position:0% +membrane and the electrons are reducing + + + align:start position:0% +membrane and the electrons are reducing +equivalents are passed to oxygen to make + + align:start position:0% +equivalents are passed to oxygen to make + + + align:start position:0% +equivalents are passed to oxygen to make +water this process is highly exergonic + + align:start position:0% +water this process is highly exergonic + + + align:start position:0% +water this process is highly exergonic +and we'll do a model calculation in a + + align:start position:0% +and we'll do a model calculation in a + + + align:start position:0% +and we'll do a model calculation in a +minute to show just how energy-yielding + + align:start position:0% +minute to show just how energy-yielding + + + align:start position:0% +minute to show just how energy-yielding +it is resulting in the liberation of a + + align:start position:0% +it is resulting in the liberation of a + + + align:start position:0% +it is resulting in the liberation of a +lot of free energy that energy is + + align:start position:0% +lot of free energy that energy is + + + align:start position:0% +lot of free energy that energy is +captured by the movement of protons + + align:start position:0% +captured by the movement of protons + + + align:start position:0% +captured by the movement of protons +from one side of the mitochondrial inner + + align:start position:0% +from one side of the mitochondrial inner + + + align:start position:0% +from one side of the mitochondrial inner +membrane to the other side of the + + align:start position:0% +membrane to the other side of the + + + align:start position:0% +membrane to the other side of the +membrane in this process you're taking a + + align:start position:0% +membrane in this process you're taking a + + + align:start position:0% +membrane in this process you're taking a +low concentration of protons and + + align:start position:0% +low concentration of protons and + + + align:start position:0% +low concentration of protons and +creating a relatively high concentration + + align:start position:0% +creating a relatively high concentration + + + align:start position:0% +creating a relatively high concentration +of protons that's an uphill process + + align:start position:0% +of protons that's an uphill process + + + align:start position:0% +of protons that's an uphill process +that's going to require an energy input + + align:start position:0% +that's going to require an energy input + + + align:start position:0% +that's going to require an energy input +and the energy from nutrient oxidation + + align:start position:0% +and the energy from nutrient oxidation + + + align:start position:0% +and the energy from nutrient oxidation +is what powers this generation of an ion + + align:start position:0% +is what powers this generation of an ion + + + align:start position:0% +is what powers this generation of an ion +gradient concentrating the protons in a + + align:start position:0% +gradient concentrating the protons in a + + + align:start position:0% +gradient concentrating the protons in a +small defined space is kind of like + + align:start position:0% +small defined space is kind of like + + + align:start position:0% +small defined space is kind of like +charging a battery it took energy to + + align:start position:0% +charging a battery it took energy to + + + align:start position:0% +charging a battery it took energy to +create that high concentration of + + align:start position:0% +create that high concentration of + + + align:start position:0% +create that high concentration of +protons we'll see that nature invented a + + align:start position:0% +protons we'll see that nature invented a + + + align:start position:0% +protons we'll see that nature invented a +way to channel the protons back through + + align:start position:0% +way to channel the protons back through + + + align:start position:0% +way to channel the protons back through +a device and a way to capture the energy + + align:start position:0% +a device and a way to capture the energy + + + align:start position:0% +a device and a way to capture the energy +released when the gradient is dissipated + + align:start position:0% +released when the gradient is dissipated + + + align:start position:0% +released when the gradient is dissipated +that energy can be captured in various + + align:start position:0% +that energy can be captured in various + + + align:start position:0% +that energy can be captured in various +ways enabling us to be able to do useful + + align:start position:0% +ways enabling us to be able to do useful + + + align:start position:0% +ways enabling us to be able to do useful +things with it for example the energy + + align:start position:0% +things with it for example the energy + + + align:start position:0% +things with it for example the energy +could be used to accomplish the + + align:start position:0% +could be used to accomplish the + + + align:start position:0% +could be used to accomplish the +otherwise energy requiring process of + + align:start position:0% +otherwise energy requiring process of + + + align:start position:0% +otherwise energy requiring process of +putting a phosphate onto ADP to make ATP + + align:start position:0% +putting a phosphate onto ADP to make ATP + + + align:start position:0% +putting a phosphate onto ADP to make ATP +and that way the energy is captured in a + + align:start position:0% +and that way the energy is captured in a + + + align:start position:0% +and that way the energy is captured in a +chemical bond alternatively let's think + + align:start position:0% +chemical bond alternatively let's think + + + align:start position:0% +chemical bond alternatively let's think +of a situation in which you may need to + + align:start position:0% +of a situation in which you may need to + + + align:start position:0% +of a situation in which you may need to +generate heat you could allow the proton + + align:start position:0% +generate heat you could allow the proton + + + align:start position:0% +generate heat you could allow the proton +simply to flow back across the membrane + + align:start position:0% +simply to flow back across the membrane + + + align:start position:0% +simply to flow back across the membrane +through a channel the energy of the + + align:start position:0% +through a channel the energy of the + + + align:start position:0% +through a channel the energy of the +proton gradient would then be released + + align:start position:0% +proton gradient would then be released + + + align:start position:0% +proton gradient would then be released +as heat thirdly we can perhaps allow the + + align:start position:0% +as heat thirdly we can perhaps allow the + + + align:start position:0% +as heat thirdly we can perhaps allow the +protons to flow back through a device + + align:start position:0% +protons to flow back through a device + + + align:start position:0% +protons to flow back through a device +that creates rotary movement and that's + + align:start position:0% +that creates rotary movement and that's + + + align:start position:0% +that creates rotary movement and that's +how for example a flagellar motor can + + align:start position:0% +how for example a flagellar motor can + + + align:start position:0% +how for example a flagellar motor can +spin to move a bacterium from one place + + align:start position:0% +spin to move a bacterium from one place + + + align:start position:0% +spin to move a bacterium from one place +to another let's now turn to panel C + + align:start position:0% +to another let's now turn to panel C + + + align:start position:0% +to another let's now turn to panel C +we've seen earlier that oxidation can + + align:start position:0% +we've seen earlier that oxidation can + + + align:start position:0% +we've seen earlier that oxidation can +result in the production of nadh or + + align:start position:0% +result in the production of nadh or + + + align:start position:0% +result in the production of nadh or +fadh2 to begin let's consider NADH in + + align:start position:0% +fadh2 to begin let's consider NADH in + + + align:start position:0% +fadh2 to begin let's consider NADH in +this panel you can see the NADH oxidized + + align:start position:0% +this panel you can see the NADH oxidized + + + align:start position:0% +this panel you can see the NADH oxidized +where the electrons flow and it doesn't + + align:start position:0% +where the electrons flow and it doesn't + + + align:start position:0% +where the electrons flow and it doesn't +matter what the path of the flow is all + + align:start position:0% +matter what the path of the flow is all + + + align:start position:0% +matter what the path of the flow is all +the way to oxygen thermodynamics gives + + align:start position:0% +the way to oxygen thermodynamics gives + + + align:start position:0% +the way to oxygen thermodynamics gives +us the tools to calculate how much + + align:start position:0% +us the tools to calculate how much + + + align:start position:0% +us the tools to calculate how much +energy you would get in this process + + align:start position:0% +energy you would get in this process + + + align:start position:0% +energy you would get in this process +Joanne taught you a lot about + + align:start position:0% +Joanne taught you a lot about + + + align:start position:0% +Joanne taught you a lot about +thermodynamics and biological systems + + align:start position:0% +thermodynamics and biological systems + + + align:start position:0% +thermodynamics and biological systems +and this is just a repeat of what she + + align:start position:0% +and this is just a repeat of what she + + + align:start position:0% +and this is just a repeat of what she +said but what I'm going to do is put + + align:start position:0% +said but what I'm going to do is put + + + align:start position:0% +said but what I'm going to do is put +what she said into a concrete practical + + align:start position:0% +what she said into a concrete practical + + + align:start position:0% +what she said into a concrete practical +example I've drawn out at the bottom of + + align:start position:0% +example I've drawn out at the bottom of + + + align:start position:0% +example I've drawn out at the bottom of +panels see the overall reaction showing + + align:start position:0% +panels see the overall reaction showing + + + align:start position:0% +panels see the overall reaction showing +electrons going from NADH to oxygen in + + align:start position:0% +electrons going from NADH to oxygen in + + + align:start position:0% +electrons going from NADH to oxygen in +the four + + align:start position:0% +the four + + + align:start position:0% +the four +word direction now of course we could + + align:start position:0% +word direction now of course we could + + + align:start position:0% +word direction now of course we could +also think about the back reaction where + + align:start position:0% +also think about the back reaction where + + + align:start position:0% +also think about the back reaction where +electrons would flow from water in to + + align:start position:0% +electrons would flow from water in to + + + align:start position:0% +electrons would flow from water in to +NAD+ to form NADH at this point this is + + align:start position:0% +NAD+ to form NADH at this point this is + + + align:start position:0% +NAD+ to form NADH at this point this is +just an equation on a piece of paper and + + align:start position:0% +just an equation on a piece of paper and + + + align:start position:0% +just an equation on a piece of paper and +we don't know in which direction the + + align:start position:0% +we don't know in which direction the + + + align:start position:0% +we don't know in which direction the +reaction is overall favorable that is is + + align:start position:0% +reaction is overall favorable that is is + + + align:start position:0% +reaction is overall favorable that is is +it favorable in the forward direction as + + align:start position:0% +it favorable in the forward direction as + + + align:start position:0% +it favorable in the forward direction as +drawn left to right or in the reverse + + align:start position:0% +drawn left to right or in the reverse + + + align:start position:0% +drawn left to right or in the reverse +direction right to left the reaction + + align:start position:0% +direction right to left the reaction + + + align:start position:0% +direction right to left the reaction +from left to right is the direction we + + align:start position:0% +from left to right is the direction we + + + align:start position:0% +from left to right is the direction we +usually think about in the context of + + align:start position:0% +usually think about in the context of + + + align:start position:0% +usually think about in the context of +nutrient oxidation interestingly the + + align:start position:0% +nutrient oxidation interestingly the + + + align:start position:0% +nutrient oxidation interestingly the +reaction from right to left is + + align:start position:0% +reaction from right to left is + + + align:start position:0% +reaction from right to left is +photosynthesis so both directions are + + align:start position:0% +photosynthesis so both directions are + + + align:start position:0% +photosynthesis so both directions are +biologically used but we'll see that one + + align:start position:0% +biologically used but we'll see that one + + + align:start position:0% +biologically used but we'll see that one +of the directions will require + + align:start position:0% +of the directions will require + + + align:start position:0% +of the directions will require +substantial energy input in order to + + align:start position:0% +substantial energy input in order to + + + align:start position:0% +substantial energy input in order to +make it biologically useful probably you + + align:start position:0% +make it biologically useful probably you + + + align:start position:0% +make it biologically useful probably you +can appreciate that photosynthesis is + + align:start position:0% +can appreciate that photosynthesis is + + + align:start position:0% +can appreciate that photosynthesis is +the energy requiring process because we + + align:start position:0% +the energy requiring process because we + + + align:start position:0% +the energy requiring process because we +all know that sunlight is needed to make + + align:start position:0% +all know that sunlight is needed to make + + + align:start position:0% +all know that sunlight is needed to make +the process thermodynamically and + + align:start position:0% +the process thermodynamically and + + + align:start position:0% +the process thermodynamically and +kinetically favorable we don't cover + + align:start position:0% +kinetically favorable we don't cover + + + align:start position:0% +kinetically favorable we don't cover +photosynthesis in 507 so let me say a + + align:start position:0% +photosynthesis in 507 so let me say a + + + align:start position:0% +photosynthesis in 507 so let me say a +few words about it in photosynthesis + + align:start position:0% +few words about it in photosynthesis + + + align:start position:0% +few words about it in photosynthesis +nature takes electrons from water and + + align:start position:0% +nature takes electrons from water and + + + align:start position:0% +nature takes electrons from water and +uses them to reduce nadp+ to nadph note + + align:start position:0% +uses them to reduce nadp+ to nadph note + + + align:start position:0% +uses them to reduce nadp+ to nadph note +that I said in adp plus and not any d + + align:start position:0% +that I said in adp plus and not any d + + + align:start position:0% +that I said in adp plus and not any d +plus but for the purposes here they are + + align:start position:0% +plus but for the purposes here they are + + + align:start position:0% +plus but for the purposes here they are +equivalent in the case of photosynthesis + + align:start position:0% +equivalent in the case of photosynthesis + + + align:start position:0% +equivalent in the case of photosynthesis +we know intuitively that the overall + + align:start position:0% +we know intuitively that the overall + + + align:start position:0% +we know intuitively that the overall +process is power bud light so in going + + align:start position:0% +process is power bud light so in going + + + align:start position:0% +process is power bud light so in going +from right to left the process + + align:start position:0% +from right to left the process + + + align:start position:0% +from right to left the process +intuitively once again should require + + align:start position:0% +intuitively once again should require + + + align:start position:0% +intuitively once again should require +energy + + align:start position:0% +energy + + + align:start position:0% +energy +by contrast nutrient oxidation where we + + align:start position:0% +by contrast nutrient oxidation where we + + + align:start position:0% +by contrast nutrient oxidation where we +go from left to right in this equation + + align:start position:0% +go from left to right in this equation + + + align:start position:0% +go from left to right in this equation +should be a process that generates + + align:start position:0% +should be a process that generates + + + align:start position:0% +should be a process that generates +energy but intuition aside let's do the + + align:start position:0% +energy but intuition aside let's do the + + + align:start position:0% +energy but intuition aside let's do the +calculation so the question is in which + + align:start position:0% +calculation so the question is in which + + + align:start position:0% +calculation so the question is in which +direction is the equation at the bottom + + align:start position:0% +direction is the equation at the bottom + + + align:start position:0% +direction is the equation at the bottom +of paneled seat thermodynamically + + align:start position:0% +of paneled seat thermodynamically + + + align:start position:0% +of paneled seat thermodynamically +favorable left to right or right to left + + align:start position:0% +favorable left to right or right to left + + + align:start position:0% +favorable left to right or right to left +let's take a look now at panel D you'll + + align:start position:0% +let's take a look now at panel D you'll + + + align:start position:0% +let's take a look now at panel D you'll +see here that I have split the master + + align:start position:0% +see here that I have split the master + + + align:start position:0% +see here that I have split the master +equation into two half reactions + + align:start position:0% +equation into two half reactions + + + align:start position:0% +equation into two half reactions +I always write out the half reaction in + + align:start position:0% +I always write out the half reaction in + + + align:start position:0% +I always write out the half reaction in +the direction of reduction for example + + align:start position:0% +the direction of reduction for example + + + align:start position:0% +the direction of reduction for example +look at the second half reaction it + + align:start position:0% +look at the second half reaction it + + + align:start position:0% +look at the second half reaction it +shows that half a mole of oxygen plus + + align:start position:0% +shows that half a mole of oxygen plus + + + align:start position:0% +shows that half a mole of oxygen plus +two protons plus two electrons go to + + align:start position:0% +two protons plus two electrons go to + + + align:start position:0% +two protons plus two electrons go to +water again I've written out these + + align:start position:0% +water again I've written out these + + + align:start position:0% +water again I've written out these +reactions in the direction of reduction + + align:start position:0% +reactions in the direction of reduction + + + align:start position:0% +reactions in the direction of reduction +it's just the way I do it + + align:start position:0% +it's just the way I do it + + + align:start position:0% +it's just the way I do it +next I go to the redox chart that is a + + align:start position:0% +next I go to the redox chart that is a + + + align:start position:0% +next I go to the redox chart that is a +table of redox potentials of + + align:start position:0% +table of redox potentials of + + + align:start position:0% +table of redox potentials of +electrochemical reactions and I figure + + align:start position:0% +electrochemical reactions and I figure + + + align:start position:0% +electrochemical reactions and I figure +out what the standard energies are for + + align:start position:0% +out what the standard energies are for + + + align:start position:0% +out what the standard energies are for +each of these half reactions as you can + + align:start position:0% +each of these half reactions as you can + + + align:start position:0% +each of these half reactions as you can +see it's 0.32 volts and plus point eight + + align:start position:0% +see it's 0.32 volts and plus point eight + + + align:start position:0% +see it's 0.32 volts and plus point eight +two volts respectively for the two half + + align:start position:0% +two volts respectively for the two half + + + align:start position:0% +two volts respectively for the two half +reactions next I use variant of the + + align:start position:0% +reactions next I use variant of the + + + align:start position:0% +reactions next I use variant of the +Nernst equation to calculate the free + + align:start position:0% +Nernst equation to calculate the free + + + align:start position:0% +Nernst equation to calculate the free +energy and ultimately the directionality + + align:start position:0% +energy and ultimately the directionality + + + align:start position:0% +energy and ultimately the directionality +of the reaction the equation I use is + + align:start position:0% +of the reaction the equation I use is + + + align:start position:0% +of the reaction the equation I use is +Delta G naught prime equals n times + + align:start position:0% +Delta G naught prime equals n times + + + align:start position:0% +Delta G naught prime equals n times +Faraday's constant times the difference + + align:start position:0% +Faraday's constant times the difference + + + align:start position:0% +Faraday's constant times the difference +in the reduction potentials of the two + + align:start position:0% +in the reduction potentials of the two + + + align:start position:0% +in the reduction potentials of the two +half-reactions + + align:start position:0% +half-reactions + + + align:start position:0% +half-reactions +to find Delta e naught Prime we look at + + align:start position:0% +to find Delta e naught Prime we look at + + + align:start position:0% +to find Delta e naught Prime we look at +the reaction that I've written out the + + align:start position:0% +the reaction that I've written out the + + + align:start position:0% +the reaction that I've written out the +overall reaction and we look to see + + align:start position:0% +overall reaction and we look to see + + + align:start position:0% +overall reaction and we look to see +which is the electron acceptor and which + + align:start position:0% +which is the electron acceptor and which + + + align:start position:0% +which is the electron acceptor and which +is the electron donor the way the + + align:start position:0% +is the electron donor the way the + + + align:start position:0% +is the electron donor the way the +reaction was written then we subtract + + align:start position:0% +reaction was written then we subtract + + + align:start position:0% +reaction was written then we subtract +the reduction potential of the electron + + align:start position:0% +the reduction potential of the electron + + + align:start position:0% +the reduction potential of the electron +receptor from that of the electron donor + + align:start position:0% +receptor from that of the electron donor + + + align:start position:0% +receptor from that of the electron donor +the way the equation is written left to + + align:start position:0% +the way the equation is written left to + + + align:start position:0% +the way the equation is written left to +right oxygen is the electron acceptor + + align:start position:0% +right oxygen is the electron acceptor + + + align:start position:0% +right oxygen is the electron acceptor +its reduction potential is plus 0.8 2 + + align:start position:0% +its reduction potential is plus 0.8 2 + + + align:start position:0% +its reduction potential is plus 0.8 2 +volts so Delta e naught prime is plus + + align:start position:0% +volts so Delta e naught prime is plus + + + align:start position:0% +volts so Delta e naught prime is plus +0.8 to minus a minus 0.32 or a total of + + align:start position:0% +0.8 to minus a minus 0.32 or a total of + + + align:start position:0% +0.8 to minus a minus 0.32 or a total of +plus 1 point 1 4 volts in the Nernst + + align:start position:0% +plus 1 point 1 4 volts in the Nernst + + + align:start position:0% +plus 1 point 1 4 volts in the Nernst +equation the number of electron + + align:start position:0% +equation the number of electron + + + align:start position:0% +equation the number of electron +transferred in this case is 2 in + + align:start position:0% +transferred in this case is 2 in + + + align:start position:0% +transferred in this case is 2 in +Faraday's constant is 96.4 kilojoules + + align:start position:0% +Faraday's constant is 96.4 kilojoules + + + align:start position:0% +Faraday's constant is 96.4 kilojoules +per mole times volts if you do the math + + align:start position:0% +per mole times volts if you do the math + + + align:start position:0% +per mole times volts if you do the math +or as we say at MIT plug and chug what + + align:start position:0% +or as we say at MIT plug and chug what + + + align:start position:0% +or as we say at MIT plug and chug what +you find out is that the free energy + + align:start position:0% +you find out is that the free energy + + + align:start position:0% +you find out is that the free energy +change of the reaction that's written + + align:start position:0% +change of the reaction that's written + + + align:start position:0% +change of the reaction that's written +the NADH oxidation reaction is minus 220 + + align:start position:0% +the NADH oxidation reaction is minus 220 + + + align:start position:0% +the NADH oxidation reaction is minus 220 +kilojoules per mole this number is + + align:start position:0% +kilojoules per mole this number is + + + align:start position:0% +kilojoules per mole this number is +negative and that means the reaction is + + align:start position:0% +negative and that means the reaction is + + + align:start position:0% +negative and that means the reaction is +favorable as drawn that is the reaction + + align:start position:0% +favorable as drawn that is the reaction + + + align:start position:0% +favorable as drawn that is the reaction +goes from left to right the 220 + + align:start position:0% +goes from left to right the 220 + + + align:start position:0% +goes from left to right the 220 +kilojoules is the amount of energy + + align:start position:0% +kilojoules is the amount of energy + + + align:start position:0% +kilojoules is the amount of energy +that's available for the three purposes + + align:start position:0% +that's available for the three purposes + + + align:start position:0% +that's available for the three purposes +of the pathway that is ATP synthesis + + align:start position:0% +of the pathway that is ATP synthesis + + + align:start position:0% +of the pathway that is ATP synthesis +heat generation or movement if we were + + align:start position:0% +heat generation or movement if we were + + + align:start position:0% +heat generation or movement if we were +going to make ATP we would divide 220 by + + align:start position:0% +going to make ATP we would divide 220 by + + + align:start position:0% +going to make ATP we would divide 220 by +32 because we get about 30 + + align:start position:0% +32 because we get about 30 + + + align:start position:0% +32 because we get about 30 +kilojoules of energy by hydrolysis of + + align:start position:0% +kilojoules of energy by hydrolysis of + + + align:start position:0% +kilojoules of energy by hydrolysis of +ATP and we can calculate that we're + + align:start position:0% +ATP and we can calculate that we're + + + align:start position:0% +ATP and we can calculate that we're +going to get something in the order of + + align:start position:0% +going to get something in the order of + + + align:start position:0% +going to get something in the order of +about three atps for every NADH that + + align:start position:0% +about three atps for every NADH that + + + align:start position:0% +about three atps for every NADH that +gives up two electrons to the electron + + align:start position:0% +gives up two electrons to the electron + + + align:start position:0% +gives up two electrons to the electron +transport chain we could easily do the + + align:start position:0% +transport chain we could easily do the + + + align:start position:0% +transport chain we could easily do the +same oxidation reaction and study fadh2 + + align:start position:0% +same oxidation reaction and study fadh2 + + + align:start position:0% +same oxidation reaction and study fadh2 +but in this case we would calculate that + + align:start position:0% +but in this case we would calculate that + + + align:start position:0% +but in this case we would calculate that +we would get actually less energy + + align:start position:0% +we would get actually less energy + + + align:start position:0% +we would get actually less energy +because the oxidation potential of + + align:start position:0% +because the oxidation potential of + + + align:start position:0% +because the oxidation potential of +Flavin's as compared to nad is different + + align:start position:0% +Flavin's as compared to nad is different + + + align:start position:0% +Flavin's as compared to nad is different +in that case that is fadh2 oxidation + + align:start position:0% +in that case that is fadh2 oxidation + + + align:start position:0% +in that case that is fadh2 oxidation +will get only about two atps per fadh2 + + align:start position:0% +will get only about two atps per fadh2 + + + align:start position:0% +will get only about two atps per fadh2 +oxidize so the fadh2 produced in the + + align:start position:0% +oxidize so the fadh2 produced in the + + + align:start position:0% +oxidize so the fadh2 produced in the +succinate dehydrogenase step of the TCA + + align:start position:0% +succinate dehydrogenase step of the TCA + + + align:start position:0% +succinate dehydrogenase step of the TCA +cycle is less energy yielding man + + align:start position:0% +cycle is less energy yielding man + + + align:start position:0% +cycle is less energy yielding man +for example the oxidation of malate to + + align:start position:0% +for example the oxidation of malate to + + + align:start position:0% +for example the oxidation of malate to +oxaloacetate that occurs later in the + + align:start position:0% +oxaloacetate that occurs later in the + + + align:start position:0% +oxaloacetate that occurs later in the +pathway let's turn now to storyboard + + align:start position:0% +pathway let's turn now to storyboard + + + align:start position:0% +pathway let's turn now to storyboard +thirteen we now have an idea of the + + align:start position:0% +thirteen we now have an idea of the + + + align:start position:0% +thirteen we now have an idea of the +rough amount of energy that's going to + + align:start position:0% +rough amount of energy that's going to + + + align:start position:0% +rough amount of energy that's going to +be generated by nutrient oxidation next + + align:start position:0% +be generated by nutrient oxidation next + + + align:start position:0% +be generated by nutrient oxidation next +we're going to look a little bit more in + + align:start position:0% +we're going to look a little bit more in + + + align:start position:0% +we're going to look a little bit more in +detail at the mechanism by which the + + align:start position:0% +detail at the mechanism by which the + + + align:start position:0% +detail at the mechanism by which the +electrons are transported from the + + align:start position:0% +electrons are transported from the + + + align:start position:0% +electrons are transported from the +reduced substances that constitute our + + align:start position:0% +reduced substances that constitute our + + + align:start position:0% +reduced substances that constitute our +electron donors nadh and fadh2 to + + align:start position:0% +electron donors nadh and fadh2 to + + + align:start position:0% +electron donors nadh and fadh2 to +molecular oxygen or whatever the + + align:start position:0% +molecular oxygen or whatever the + + + align:start position:0% +molecular oxygen or whatever the +terminal electron acceptor is in the + + align:start position:0% +terminal electron acceptor is in the + + + align:start position:0% +terminal electron acceptor is in the +biological system under study as we've + + align:start position:0% +biological system under study as we've + + + align:start position:0% +biological system under study as we've +seen the electron transfer process that + + align:start position:0% +seen the electron transfer process that + + + align:start position:0% +seen the electron transfer process that +we've been studying liberate energy and + + align:start position:0% +we've been studying liberate energy and + + + align:start position:0% +we've been studying liberate energy and +that energy is going to be used to power + + align:start position:0% +that energy is going to be used to power + + + align:start position:0% +that energy is going to be used to power +pumps that will transport protons from + + align:start position:0% +pumps that will transport protons from + + + align:start position:0% +pumps that will transport protons from +the matrix of the mitochondrion out into + + align:start position:0% +the matrix of the mitochondrion out into + + + align:start position:0% +the matrix of the mitochondrion out into +the intermembrane space between the + + align:start position:0% +the intermembrane space between the + + + align:start position:0% +the intermembrane space between the +mitochondrial inner and outer membranes + + align:start position:0% +mitochondrial inner and outer membranes + + + align:start position:0% +mitochondrial inner and outer membranes +in the case of electron transport with + + align:start position:0% +in the case of electron transport with + + + align:start position:0% +in the case of electron transport with +the goal of ATP synthesis the protons + + align:start position:0% +the goal of ATP synthesis the protons + + + align:start position:0% +the goal of ATP synthesis the protons +that are generated in the intermembrane + + align:start position:0% +that are generated in the intermembrane + + + align:start position:0% +that are generated in the intermembrane +space will be allowed to flow back + + align:start position:0% +space will be allowed to flow back + + + align:start position:0% +space will be allowed to flow back +through a device that mechanically + + align:start position:0% +through a device that mechanically + + + align:start position:0% +through a device that mechanically +couples motion that is the spinning of a + + align:start position:0% +couples motion that is the spinning of a + + + align:start position:0% +couples motion that is the spinning of a +shaft to drive conformational changes in + + align:start position:0% +shaft to drive conformational changes in + + + align:start position:0% +shaft to drive conformational changes in +enzymes that will allow the otherwise + + align:start position:0% +enzymes that will allow the otherwise + + + align:start position:0% +enzymes that will allow the otherwise +endergonic synthesis of ATP from ADP and + + align:start position:0% +endergonic synthesis of ATP from ADP and + + + align:start position:0% +endergonic synthesis of ATP from ADP and +inorganic phosphate that machine is + + align:start position:0% +inorganic phosphate that machine is + + + align:start position:0% +inorganic phosphate that machine is +called the ATP synthase let's look at + + align:start position:0% +called the ATP synthase let's look at + + + align:start position:0% +called the ATP synthase let's look at +panel a this panel shows the details of + + align:start position:0% +panel a this panel shows the details of + + + align:start position:0% +panel a this panel shows the details of +the electron transport system it looks a + + align:start position:0% +the electron transport system it looks a + + + align:start position:0% +the electron transport system it looks a +little bit complicated but let's not + + align:start position:0% +little bit complicated but let's not + + + align:start position:0% +little bit complicated but let's not +lose sight of the fact + + align:start position:0% +lose sight of the fact + + + align:start position:0% +lose sight of the fact +what it's all about is powering pumps + + align:start position:0% +what it's all about is powering pumps + + + align:start position:0% +what it's all about is powering pumps +pumps that pump protons in the lower + + align:start position:0% +pumps that pump protons in the lower + + + align:start position:0% +pumps that pump protons in the lower +left of the panel we see the TCA cycle + + align:start position:0% +left of the panel we see the TCA cycle + + + align:start position:0% +left of the panel we see the TCA cycle +generating nadh and fadh2 the nadh + + align:start position:0% +generating nadh and fadh2 the nadh + + + align:start position:0% +generating nadh and fadh2 the nadh +approaches complex one of the + + align:start position:0% +approaches complex one of the + + + align:start position:0% +approaches complex one of the +mitochondrial inner membrane complex one + + align:start position:0% +mitochondrial inner membrane complex one + + + align:start position:0% +mitochondrial inner membrane complex one +is an NADH dehydrogenase enzyme the + + align:start position:0% +is an NADH dehydrogenase enzyme the + + + align:start position:0% +is an NADH dehydrogenase enzyme the +enzyme has a flavin that accepts the + + align:start position:0% +enzyme has a flavin that accepts the + + + align:start position:0% +enzyme has a flavin that accepts the +electrons from NADH passes them along to + + align:start position:0% +electrons from NADH passes them along to + + + align:start position:0% +electrons from NADH passes them along to +iron sulfur centers and then to a + + align:start position:0% +iron sulfur centers and then to a + + + align:start position:0% +iron sulfur centers and then to a +variety of cytochromes and moves the + + align:start position:0% +variety of cytochromes and moves the + + + align:start position:0% +variety of cytochromes and moves the +electrons up to the point where they're + + align:start position:0% +electrons up to the point where they're + + + align:start position:0% +electrons up to the point where they're +going to be transferred to coenzyme q in + + align:start position:0% +going to be transferred to coenzyme q in + + + align:start position:0% +going to be transferred to coenzyme q in +its oxidized form coenzyme q binds to + + align:start position:0% +its oxidized form coenzyme q binds to + + + align:start position:0% +its oxidized form coenzyme q binds to +complex one the oxidized form of + + align:start position:0% +complex one the oxidized form of + + + align:start position:0% +complex one the oxidized form of +coenzyme q will be reduced first to a + + align:start position:0% +coenzyme q will be reduced first to a + + + align:start position:0% +coenzyme q will be reduced first to a +semi CRO known and then to a + + align:start position:0% +semi CRO known and then to a + + + align:start position:0% +semi CRO known and then to a +hydroquinone which are located as shown + + align:start position:0% +hydroquinone which are located as shown + + + align:start position:0% +hydroquinone which are located as shown +inside the mitochondrial inner membrane + + align:start position:0% +inside the mitochondrial inner membrane + + + align:start position:0% +inside the mitochondrial inner membrane +we usually draw them as being + + align:start position:0% +we usually draw them as being + + + align:start position:0% +we usually draw them as being +free-floating within the membrane but + + align:start position:0% +free-floating within the membrane but + + + align:start position:0% +free-floating within the membrane but +that's probably inaccurate these + + align:start position:0% +that's probably inaccurate these + + + align:start position:0% +that's probably inaccurate these +cofactors are probably bound to physical + + align:start position:0% +cofactors are probably bound to physical + + + align:start position:0% +cofactors are probably bound to physical +entities inside the mitochondrial inner + + align:start position:0% +entities inside the mitochondrial inner + + + align:start position:0% +entities inside the mitochondrial inner +membrane the picture also shows fadh2 + + align:start position:0% +membrane the picture also shows fadh2 + + + align:start position:0% +membrane the picture also shows fadh2 +from the TCA cycle interacting with + + align:start position:0% +from the TCA cycle interacting with + + + align:start position:0% +from the TCA cycle interacting with +complex 2 which is a flavin containing + + align:start position:0% +complex 2 which is a flavin containing + + + align:start position:0% +complex 2 which is a flavin containing +enzyme and it will also transfer its + + align:start position:0% +enzyme and it will also transfer its + + + align:start position:0% +enzyme and it will also transfer its +electrons to the oxidized form of + + align:start position:0% +electrons to the oxidized form of + + + align:start position:0% +electrons to the oxidized form of +coenzyme q ultimately to create the + + align:start position:0% +coenzyme q ultimately to create the + + + align:start position:0% +coenzyme q ultimately to create the +reduced coenzyme q h 2 which is the + + align:start position:0% +reduced coenzyme q h 2 which is the + + + align:start position:0% +reduced coenzyme q h 2 which is the +hydroquinone just as a point of + + align:start position:0% +hydroquinone just as a point of + + + align:start position:0% +hydroquinone just as a point of +reference to the TCA cycle complex 2 is + + align:start position:0% +reference to the TCA cycle complex 2 is + + + align:start position:0% +reference to the TCA cycle complex 2 is +also known as succinate dehydrogenase we + + align:start position:0% +also known as succinate dehydrogenase we + + + align:start position:0% +also known as succinate dehydrogenase we +haven't done fatty acid oxidation yet + + align:start position:0% +haven't done fatty acid oxidation yet + + + align:start position:0% +haven't done fatty acid oxidation yet +but there's a step in fatty acid + + align:start position:0% +but there's a step in fatty acid + + + align:start position:0% +but there's a step in fatty acid +oxidation in which an alkane is + + align:start position:0% +oxidation in which an alkane is + + + align:start position:0% +oxidation in which an alkane is +converted to an alkene the electrons + + align:start position:0% +converted to an alkene the electrons + + + align:start position:0% +converted to an alkene the electrons +from that oxidation reaction go through + + align:start position:0% +from that oxidation reaction go through + + + align:start position:0% +from that oxidation reaction go through +a flavin protein called ETF pre for + + align:start position:0% +a flavin protein called ETF pre for + + + align:start position:0% +a flavin protein called ETF pre for +electron transferring flavor protein and + + align:start position:0% +electron transferring flavor protein and + + + align:start position:0% +electron transferring flavor protein and +once again those electrons flow into + + align:start position:0% +once again those electrons flow into + + + align:start position:0% +once again those electrons flow into +coenzyme q to form the reduced form of + + align:start position:0% +coenzyme q to form the reduced form of + + + align:start position:0% +coenzyme q to form the reduced form of +coenzyme q remember when we talked about + + align:start position:0% +coenzyme q remember when we talked about + + + align:start position:0% +coenzyme q remember when we talked about +the glycerol 3-phosphate shuttle i + + align:start position:0% +the glycerol 3-phosphate shuttle i + + + align:start position:0% +the glycerol 3-phosphate shuttle i +mentioned that there's a mitochondrial + + align:start position:0% +mentioned that there's a mitochondrial + + + align:start position:0% +mentioned that there's a mitochondrial +membrane associated glycerol 3-phosphate + + align:start position:0% +membrane associated glycerol 3-phosphate + + + align:start position:0% +membrane associated glycerol 3-phosphate +dehydrogenase you can see that enzyme at + + align:start position:0% +dehydrogenase you can see that enzyme at + + + align:start position:0% +dehydrogenase you can see that enzyme at +the top part of the inner membrane as + + align:start position:0% +the top part of the inner membrane as + + + align:start position:0% +the top part of the inner membrane as +i've drawn it and once again flavin in + + align:start position:0% +i've drawn it and once again flavin in + + + align:start position:0% +i've drawn it and once again flavin in +that enzyme will carry the electrons + + align:start position:0% +that enzyme will carry the electrons + + + align:start position:0% +that enzyme will carry the electrons +into coenzyme q generating + + align:start position:0% +into coenzyme q generating + + + align:start position:0% +into coenzyme q generating +reduced form of the cofactor qh2 the + + align:start position:0% +reduced form of the cofactor qh2 the + + + align:start position:0% +reduced form of the cofactor qh2 the +left part of this picture pretty neatly + + align:start position:0% +left part of this picture pretty neatly + + + align:start position:0% +left part of this picture pretty neatly +shows how nutrient oxidation can channel + + align:start position:0% +shows how nutrient oxidation can channel + + + align:start position:0% +shows how nutrient oxidation can channel +the electrons into a common mobile + + align:start position:0% +the electrons into a common mobile + + + align:start position:0% +the electrons into a common mobile +electron carrier coenzyme q lots of + + align:start position:0% +electron carrier coenzyme q lots of + + + align:start position:0% +electron carrier coenzyme q lots of +different fuels give up their electrons + + align:start position:0% +different fuels give up their electrons + + + align:start position:0% +different fuels give up their electrons +to a common electron carrier the + + align:start position:0% +to a common electron carrier the + + + align:start position:0% +to a common electron carrier the +hydroquinone q h2 will then go and + + align:start position:0% +hydroquinone q h2 will then go and + + + align:start position:0% +hydroquinone q h2 will then go and +interact with complex three of the + + align:start position:0% +interact with complex three of the + + + align:start position:0% +interact with complex three of the +electron transport chain in complex + + align:start position:0% +electron transport chain in complex + + + align:start position:0% +electron transport chain in complex +three electrons will be transported + + align:start position:0% +three electrons will be transported + + + align:start position:0% +three electrons will be transported +through a number of different electron + + align:start position:0% +through a number of different electron + + + align:start position:0% +through a number of different electron +relay stations and ultimately be picked + + align:start position:0% +relay stations and ultimately be picked + + + align:start position:0% +relay stations and ultimately be picked +up by cytochrome c which is in initially + + align:start position:0% +up by cytochrome c which is in initially + + + align:start position:0% +up by cytochrome c which is in initially +in its +3 oxidation state cytochrome c + + align:start position:0% +in its +3 oxidation state cytochrome c + + + align:start position:0% +in its +3 oxidation state cytochrome c +is reduced by the single electron coming + + align:start position:0% +is reduced by the single electron coming + + + align:start position:0% +is reduced by the single electron coming +through complex 3 in this process its + + align:start position:0% +through complex 3 in this process its + + + align:start position:0% +through complex 3 in this process its +iron is reduced to its +2 state this + + align:start position:0% +iron is reduced to its +2 state this + + + align:start position:0% +iron is reduced to its +2 state this +electron on cytochrome c then migrates + + align:start position:0% +electron on cytochrome c then migrates + + + align:start position:0% +electron on cytochrome c then migrates +across the outer surface of the inner + + align:start position:0% +across the outer surface of the inner + + + align:start position:0% +across the outer surface of the inner +membrane of the mitochondrion to + + align:start position:0% +membrane of the mitochondrion to + + + align:start position:0% +membrane of the mitochondrion to +interact with complex 4 when it + + align:start position:0% +interact with complex 4 when it + + + align:start position:0% +interact with complex 4 when it +interacts with complex for the reduced + + align:start position:0% +interacts with complex for the reduced + + + align:start position:0% +interacts with complex for the reduced +form of cytochrome c gives up its + + align:start position:0% +form of cytochrome c gives up its + + + align:start position:0% +form of cytochrome c gives up its +electron to a copper residue on the + + align:start position:0% +electron to a copper residue on the + + + align:start position:0% +electron to a copper residue on the +copper a subunit of complex 4 in the + + align:start position:0% +copper a subunit of complex 4 in the + + + align:start position:0% +copper a subunit of complex 4 in the +figure this complex is called Cu a the + + align:start position:0% +figure this complex is called Cu a the + + + align:start position:0% +figure this complex is called Cu a the +more common name for a complex four is + + align:start position:0% +more common name for a complex four is + + + align:start position:0% +more common name for a complex four is +cytochrome C oxidase so cytochrome C + + align:start position:0% +cytochrome C oxidase so cytochrome C + + + align:start position:0% +cytochrome C oxidase so cytochrome C +oxidase oxidizes the iron back to its + + align:start position:0% +oxidase oxidizes the iron back to its + + + align:start position:0% +oxidase oxidizes the iron back to its +iron 3 oxidation state then cytochrome C + + align:start position:0% +iron 3 oxidation state then cytochrome C + + + align:start position:0% +iron 3 oxidation state then cytochrome C +migrates back to complex 3 where it's + + align:start position:0% +migrates back to complex 3 where it's + + + align:start position:0% +migrates back to complex 3 where it's +able to pick up another electron we can + + align:start position:0% +able to pick up another electron we can + + + align:start position:0% +able to pick up another electron we can +think of cytochrome C as a mobile + + align:start position:0% +think of cytochrome C as a mobile + + + align:start position:0% +think of cytochrome C as a mobile +electron carrier that shuttles an + + align:start position:0% +electron carrier that shuttles an + + + align:start position:0% +electron carrier that shuttles an +electron along the inner surface of the + + align:start position:0% +electron along the inner surface of the + + + align:start position:0% +electron along the inner surface of the +mitochondrial inner membrane looking + + align:start position:0% +mitochondrial inner membrane looking + + + align:start position:0% +mitochondrial inner membrane looking +back at complex 4 or cytochrome C + + align:start position:0% +back at complex 4 or cytochrome C + + + align:start position:0% +back at complex 4 or cytochrome C +oxidase the electrons are passed from + + align:start position:0% +oxidase the electrons are passed from + + + align:start position:0% +oxidase the electrons are passed from +cytochrome a to a series of other + + align:start position:0% +cytochrome a to a series of other + + + align:start position:0% +cytochrome a to a series of other +electron carriers and ultimately they + + align:start position:0% +electron carriers and ultimately they + + + align:start position:0% +electron carriers and ultimately they +flow into molecular oxygen molecular + + align:start position:0% +flow into molecular oxygen molecular + + + align:start position:0% +flow into molecular oxygen molecular +oxygen is anchored on one side to heme + + align:start position:0% +oxygen is anchored on one side to heme + + + align:start position:0% +oxygen is anchored on one side to heme +a3 and on the other side to copper B + + align:start position:0% +a3 and on the other side to copper B + + + align:start position:0% +a3 and on the other side to copper B +oxygen undergoes a 4 electron reduction + + align:start position:0% +oxygen undergoes a 4 electron reduction + + + align:start position:0% +oxygen undergoes a 4 electron reduction +and picks up 4 protons along the way to + + align:start position:0% +and picks up 4 protons along the way to + + + align:start position:0% +and picks up 4 protons along the way to +form 2 molecules of water if the + + align:start position:0% +form 2 molecules of water if the + + + align:start position:0% +form 2 molecules of water if the +electron started with NADH and ends up + + align:start position:0% +electron started with NADH and ends up + + + align:start position:0% +electron started with NADH and ends up +in oxygen to form water + + align:start position:0% +in oxygen to form water + + + align:start position:0% +in oxygen to form water +you get 220 kilojoules of energy and as + + align:start position:0% +you get 220 kilojoules of energy and as + + + align:start position:0% +you get 220 kilojoules of energy and as +I said you get somewhat less if your + + align:start position:0% +I said you get somewhat less if your + + + align:start position:0% +I said you get somewhat less if your +electron started out as a reduced flavin + + align:start position:0% +electron started out as a reduced flavin + + + align:start position:0% +electron started out as a reduced flavin +now let's look at panel B I want to say + + align:start position:0% +now let's look at panel B I want to say + + + align:start position:0% +now let's look at panel B I want to say +a few words at the outset about proton + + align:start position:0% +a few words at the outset about proton + + + align:start position:0% +a few words at the outset about proton +pumps keeping in mind that the reason + + align:start position:0% +pumps keeping in mind that the reason + + + align:start position:0% +pumps keeping in mind that the reason +electrons were moved through the + + align:start position:0% +electrons were moved through the + + + align:start position:0% +electrons were moved through the +electron transport chain was to power + + align:start position:0% +electron transport chain was to power + + + align:start position:0% +electron transport chain was to power +these pumps in the lower-left part of + + align:start position:0% +these pumps in the lower-left part of + + + align:start position:0% +these pumps in the lower-left part of +the figure we can see complex one the + + align:start position:0% +the figure we can see complex one the + + + align:start position:0% +the figure we can see complex one the +transit of electrons through complex one + + align:start position:0% +transit of electrons through complex one + + + align:start position:0% +transit of electrons through complex one +from nadh results in the transport of + + align:start position:0% +from nadh results in the transport of + + + align:start position:0% +from nadh results in the transport of +four protons from the mitochondrial + + align:start position:0% +four protons from the mitochondrial + + + align:start position:0% +four protons from the mitochondrial +matrix into the intermembrane space that + + align:start position:0% +matrix into the intermembrane space that + + + align:start position:0% +matrix into the intermembrane space that +is two electrons from NADH are + + align:start position:0% +is two electrons from NADH are + + + align:start position:0% +is two electrons from NADH are +transported and coincident with that + + align:start position:0% +transported and coincident with that + + + align:start position:0% +transported and coincident with that +four protons are pumped into the + + align:start position:0% +four protons are pumped into the + + + align:start position:0% +four protons are pumped into the +intermembrane space later we'll see that + + align:start position:0% +intermembrane space later we'll see that + + + align:start position:0% +intermembrane space later we'll see that +complex 3 is location of something + + align:start position:0% +complex 3 is location of something + + + align:start position:0% +complex 3 is location of something +called the Q cycle I'm going to cover + + align:start position:0% +called the Q cycle I'm going to cover + + + align:start position:0% +called the Q cycle I'm going to cover +the proton pumping properties of the q + + align:start position:0% +the proton pumping properties of the q + + + align:start position:0% +the proton pumping properties of the q +sy q cycle in some detail in the next + + align:start position:0% +sy q cycle in some detail in the next + + + align:start position:0% +sy q cycle in some detail in the next +storyboard the passage of those two + + align:start position:0% +storyboard the passage of those two + + + align:start position:0% +storyboard the passage of those two +electrons through complex three results + + align:start position:0% +electrons through complex three results + + + align:start position:0% +electrons through complex three results +in the transport of an additional four + + align:start position:0% +in the transport of an additional four + + + align:start position:0% +in the transport of an additional four +protons into the intermembrane space + + align:start position:0% +protons into the intermembrane space + + + align:start position:0% +protons into the intermembrane space +lastly the transit of electrons through + + align:start position:0% +lastly the transit of electrons through + + + align:start position:0% +lastly the transit of electrons through +complex for the cytochrome C oxidase + + align:start position:0% +complex for the cytochrome C oxidase + + + align:start position:0% +complex for the cytochrome C oxidase +results in the transport of another two + + align:start position:0% +results in the transport of another two + + + align:start position:0% +results in the transport of another two +protons into the intermembrane space now + + align:start position:0% +protons into the intermembrane space now + + + align:start position:0% +protons into the intermembrane space now +let's look at panel C adding things up + + align:start position:0% +let's look at panel C adding things up + + + align:start position:0% +let's look at panel C adding things up +if we start with two electrons coming + + align:start position:0% +if we start with two electrons coming + + + align:start position:0% +if we start with two electrons coming +from NADH we transport about 10 protons + + align:start position:0% +from NADH we transport about 10 protons + + + align:start position:0% +from NADH we transport about 10 protons +into the intermembrane space that's + + align:start position:0% +into the intermembrane space that's + + + align:start position:0% +into the intermembrane space that's +enough to make about three molecules of + + align:start position:0% +enough to make about three molecules of + + + align:start position:0% +enough to make about three molecules of +ATP if our electrons start with fadh2 + + align:start position:0% +ATP if our electrons start with fadh2 + + + align:start position:0% +ATP if our electrons start with fadh2 +reduced flavin we only transport about + + align:start position:0% +reduced flavin we only transport about + + + align:start position:0% +reduced flavin we only transport about +six protons that's enough to make two + + align:start position:0% +six protons that's enough to make two + + + align:start position:0% +six protons that's enough to make two +ATP's if you remember making ATP is only + + align:start position:0% +ATP's if you remember making ATP is only + + + align:start position:0% +ATP's if you remember making ATP is only +one of the things that we can do with + + align:start position:0% +one of the things that we can do with + + + align:start position:0% +one of the things that we can do with +the power of the proton gradient I + + align:start position:0% +the power of the proton gradient I + + + align:start position:0% +the power of the proton gradient I +mentioned earlier that we can also use + + align:start position:0% +mentioned earlier that we can also use + + + align:start position:0% +mentioned earlier that we can also use +it to generate heat and motion let me + + align:start position:0% +it to generate heat and motion let me + + + align:start position:0% +it to generate heat and motion let me +talk for a minute about why one would + + align:start position:0% +talk for a minute about why one would + + + align:start position:0% +talk for a minute about why one would +want to generate heat newborn babies are + + align:start position:0% +want to generate heat newborn babies are + + + align:start position:0% +want to generate heat newborn babies are +like small balls they have a high + + align:start position:0% +like small balls they have a high + + + align:start position:0% +like small balls they have a high +surface to volume ratio their high + + align:start position:0% +surface to volume ratio their high + + + align:start position:0% +surface to volume ratio their high +surface to volume ratio makes heat loss + + align:start position:0% +surface to volume ratio makes heat loss + + + align:start position:0% +surface to volume ratio makes heat loss +a very significant reality and in fact a + + align:start position:0% +a very significant reality and in fact a + + + align:start position:0% +a very significant reality and in fact a +problem for the newborn they have + + align:start position:0% +problem for the newborn they have + + + align:start position:0% +problem for the newborn they have +therefore specialised mitochondria in + + align:start position:0% +therefore specialised mitochondria in + + + align:start position:0% +therefore specialised mitochondria in +their neck in an area called brown fat + + align:start position:0% +their neck in an area called brown fat + + + align:start position:0% +their neck in an area called brown fat +the fat is brown because + + align:start position:0% +the fat is brown because + + + align:start position:0% +the fat is brown because +loaded with highly colored mitochondria + + align:start position:0% +loaded with highly colored mitochondria + + + align:start position:0% +loaded with highly colored mitochondria +these mitochondria have a protein that + + align:start position:0% +these mitochondria have a protein that + + + align:start position:0% +these mitochondria have a protein that +enables the protons pumped into the + + align:start position:0% +enables the protons pumped into the + + + align:start position:0% +enables the protons pumped into the +intermembrane space to flow back freely + + align:start position:0% +intermembrane space to flow back freely + + + align:start position:0% +intermembrane space to flow back freely +into the mitochondrial matrix with the + + align:start position:0% +into the mitochondrial matrix with the + + + align:start position:0% +into the mitochondrial matrix with the +generation of heat that is they don't + + align:start position:0% +generation of heat that is they don't + + + align:start position:0% +generation of heat that is they don't +make ATP in the brown fat they make heat + + align:start position:0% +make ATP in the brown fat they make heat + + + align:start position:0% +make ATP in the brown fat they make heat +this helps promote thermal regulation in + + align:start position:0% +this helps promote thermal regulation in + + + align:start position:0% +this helps promote thermal regulation in +the baby this is also the mechanism by + + align:start position:0% +the baby this is also the mechanism by + + + align:start position:0% +the baby this is also the mechanism by +which hibernating animals such as a bear + + align:start position:0% +which hibernating animals such as a bear + + + align:start position:0% +which hibernating animals such as a bear +can maintain body temperature during the + + align:start position:0% +can maintain body temperature during the + + + align:start position:0% +can maintain body temperature during the +winter when the bear is hibernating this + + align:start position:0% +winter when the bear is hibernating this + + + align:start position:0% +winter when the bear is hibernating this +process overall is called uncoupling of + + align:start position:0% +process overall is called uncoupling of + + + align:start position:0% +process overall is called uncoupling of +electron transport from the process that + + align:start position:0% +electron transport from the process that + + + align:start position:0% +electron transport from the process that +we're going to be looking at next + + align:start position:0% +we're going to be looking at next + + + align:start position:0% +we're going to be looking at next +oxidative phosphorylation oxidative + + align:start position:0% +oxidative phosphorylation oxidative + + + align:start position:0% +oxidative phosphorylation oxidative +phosphorylation is the process by which + + align:start position:0% +phosphorylation is the process by which + + + align:start position:0% +phosphorylation is the process by which +we're going to be making ATP uncoupling + + align:start position:0% +we're going to be making ATP uncoupling + + + align:start position:0% +we're going to be making ATP uncoupling +is also a process used by some flowers + + align:start position:0% +is also a process used by some flowers + + + align:start position:0% +is also a process used by some flowers +that have to come up through frozen + + align:start position:0% +that have to come up through frozen + + + align:start position:0% +that have to come up through frozen +ground in the springtime for example the + + align:start position:0% +ground in the springtime for example the + + + align:start position:0% +ground in the springtime for example the +skunk cabbage and the crocus are very + + align:start position:0% +skunk cabbage and the crocus are very + + + align:start position:0% +skunk cabbage and the crocus are very +good at uncoupling electron transport + + align:start position:0% +good at uncoupling electron transport + + + align:start position:0% +good at uncoupling electron transport +from oxidative phosphorylation + + align:start position:0% +from oxidative phosphorylation + + + align:start position:0% +from oxidative phosphorylation +they let the protons in the proton + + align:start position:0% +they let the protons in the proton + + + align:start position:0% +they let the protons in the proton +gradient flow back across the + + align:start position:0% +gradient flow back across the + + + align:start position:0% +gradient flow back across the +mitochondrial inner membrane and by + + align:start position:0% +mitochondrial inner membrane and by + + + align:start position:0% +mitochondrial inner membrane and by +doing so these plants are able to + + align:start position:0% +doing so these plants are able to + + + align:start position:0% +doing so these plants are able to +generate heat that will allow them to + + align:start position:0% +generate heat that will allow them to + + + align:start position:0% +generate heat that will allow them to +grow at sub-freezing temperatures in + + align:start position:0% +grow at sub-freezing temperatures in + + + align:start position:0% +grow at sub-freezing temperatures in +other words the plant itself becomes a + + align:start position:0% +other words the plant itself becomes a + + + align:start position:0% +other words the plant itself becomes a +little heater at this point let me give + + align:start position:0% +little heater at this point let me give + + + align:start position:0% +little heater at this point let me give +you a little bit of a preview of how we + + align:start position:0% +you a little bit of a preview of how we + + + align:start position:0% +you a little bit of a preview of how we +use this proton gradient in order to + + align:start position:0% +use this proton gradient in order to + + + align:start position:0% +use this proton gradient in order to +synthesize ATP as we've seen it took + + align:start position:0% +synthesize ATP as we've seen it took + + + align:start position:0% +synthesize ATP as we've seen it took +energy in order to create a gradient in + + align:start position:0% +energy in order to create a gradient in + + + align:start position:0% +energy in order to create a gradient in +which there are protons in the + + align:start position:0% +which there are protons in the + + + align:start position:0% +which there are protons in the +intermembrane space and protons are + + align:start position:0% +intermembrane space and protons are + + + align:start position:0% +intermembrane space and protons are +chemical entities so we've created a + + align:start position:0% +chemical entities so we've created a + + + align:start position:0% +chemical entities so we've created a +chemical gradient but also we're putting + + align:start position:0% +chemical gradient but also we're putting + + + align:start position:0% +chemical gradient but also we're putting +a very high positive charge density in + + align:start position:0% +a very high positive charge density in + + + align:start position:0% +a very high positive charge density in +the small enclosed inter membrane space + + align:start position:0% +the small enclosed inter membrane space + + + align:start position:0% +the small enclosed inter membrane space +so we've also created an electrochemical + + align:start position:0% +so we've also created an electrochemical + + + align:start position:0% +so we've also created an electrochemical +gradient it is the release of those + + align:start position:0% +gradient it is the release of those + + + align:start position:0% +gradient it is the release of those +gradients that empowers many of our + + align:start position:0% +gradients that empowers many of our + + + align:start position:0% +gradients that empowers many of our +vital processes for a final comment + + align:start position:0% +vital processes for a final comment + + + align:start position:0% +vital processes for a final comment +please see panel D Peter Mitchell + + align:start position:0% +please see panel D Peter Mitchell + + + align:start position:0% +please see panel D Peter Mitchell +figured out how the energy in that + + align:start position:0% +figured out how the energy in that + + + align:start position:0% +figured out how the energy in that +electrochemical gradient could be + + align:start position:0% +electrochemical gradient could be + + + align:start position:0% +electrochemical gradient could be +released and converted into the energy + + align:start position:0% +released and converted into the energy + + + align:start position:0% +released and converted into the energy +it takes to make chemical bonds + + align:start position:0% +it takes to make chemical bonds + + + align:start position:0% +it takes to make chemical bonds +Mitchell's conclusions serve as the + + align:start position:0% +Mitchell's conclusions serve as the + + + align:start position:0% +Mitchell's conclusions serve as the +basis of what is called the chemiosmotic + + align:start position:0% +basis of what is called the chemiosmotic + + + align:start position:0% +basis of what is called the chemiosmotic +coupling hypothesis and we'd be looking + + align:start position:0% +coupling hypothesis and we'd be looking + + + align:start position:0% +coupling hypothesis and we'd be looking +at that in some detail later \ No newline at end of file diff --git a/e3Bsb1mELcc.txt b/e3Bsb1mELcc.txt new file mode 100644 index 0000000000000000000000000000000000000000..a30953fd3f0516f14fcbabab429a11c671984272 --- /dev/null +++ b/e3Bsb1mELcc.txt @@ -0,0 +1,2761 @@ +The following content is +provided under a Creative + +Commons license. + +Your support will help MIT +OpenCourseWare continue to + +offer high-quality educational +resources for free. + +To make a donation or view +additional materials from + +hundreds of MIT courses, visit +mitopencourseware@ocw.mit.edu. + +PROFESSOR: Economics-- + +oligopoly. + +Which is basically trying +to move towards the most + +realistic modeling of +markets that we can. + +We've talked about two extreme +versions of modeling markets. + +One is perfect competition, +which is the extreme case of + +perfect entry and exit. + +Free entry and exit. + +Perfect consumer information. + +An idealized market. + +We know that doesn't really +exist in practice anywhere. + +The second extreme was monopoly, +which we do see in + +practice in some places. + +In particular, when there's +natural monopolies. + +We do see that. + +But that's still doesn't +describe most markets. + +Most markets are better +described as oligopolies. + +These are markets where there's +more than one market + +player, yet where each firm is +large enough to actually + +affect the price. + +So an oligopoly market is where +there'll be a small + +number of firms in the market +with substantial barriers to + +entry from additional firms. +An oligopoly market where + +there's a small number of firms +with enough barriers to + +entry that additional +firms don't enter. + +So the classic example +of an oligopoly + +industry is the auto industry. + +Here's a market with a small +number of dominant players. + +There's been some entry and exit +over time, obviously, but + +it moves pretty slowly. + +By and large it's a market +where there's + +very limited entry. + +And the question is, how do +firms behave in this market? + +Obviously it's not like perfect +competition where they + +can lazily take a price out of +the market and just produce + +based on that price. + +But it's also not the same as +monopoly where they can just + +get to set the price and +not worry about what + +other people do. + +They're in this in-between +situation where they have + +price setting power. + +They have some market power but +in a context where they + +have to worry about +competitors. + +And so in this context there are +two different ways firms + +can behave. It's important +to lay out to start. + +There's two different ways for +firms to behave. They can + +behave cooperatively or +non-cooperatively. + +If they behave cooperatively +we say + +that they form a cartel. + +So our cartel is what happens +when oligopolistic firms, when + +firms in an oligopolistic market +behave cooperatively to + +determine the outcome. + +We call that a cartel. + +The classic example, of course, +here being OPEC. + +The Organization of Petroleum +Exporting Countries, which is + +a cartel that drives +the price of oil. + +Those countries cooperate in how +much oil they produce to + +move the price up or +down according to + +what the group desires. + +And what cartels do is +essentially turn oligopolies + +into monopolies. + +So what cartelization does, what +a cooperative equilibrium + +does is essentially say, let's +all get together and behave as + +if we're one big monopoly +by cooperating. + +And therefore, if you cooperate +you can get all the + +wonderful things monopolies get: +huge market power, huge + +markets et cetera. + +But as we'll talk about next +time, it turns out to be + +pretty hard to get a cooperative +oligopoly. + +There's lots of reasons why +it might fall apart. + +And that's why in most +oligopolistic markets firms + +behave non cooperatively. + +In most oligopolistic markets +firms are behaving + +non-cooperatively. + +They're competing with each +other, not cooperating. + +And that's what we're going to +spend today analyzing is the + +case of non-cooperative +oligopolies. + +Yeah? + +AUDIENCE: [INAUDIBLE]? + +PROFESSOR: Depends +on the context. + +In the US, and I'll talk about +this, in the US there's + +anti-trust legislation which +can make it illegal in many + +contexts to cooperate. + +Obviously OPEC is not subject +to some world legislation. + +But even in the US there can be +implicit cartelization and + +implicit cooperation, and +we'll talk about that. + +It's a good question. + +So technically you're right. + +Technically it is illegal in +the US in most contexts to + +form a cooperative, +to form a cartel. + +Whether in practice those laws +can be enforced is an + +interesting, legitimate +question. + +So today we want to focus on +the case of non-cooperative + +oligopolies. + +And to do so we're going +to turn to a new tool. + +And one of the fundamental tools +of economics in the last + +30 years which is game theory. + +So today we're going to talk +about game theory. + +Game theory is a tool of +economics that was not really + +used early in economics but +has come to dominate + +theoretical economics over +the past 30 or 40 years. + +And basically the way that game +theory works is to think, + +literally, of oligopolistic +firms as engaging in a game. + +So when you play, don't want to +say play Monopoly, that's + +confusing terms. When +you play Sorry! + +or whatever with someone, or +play some online game with + +someone, you're competing +to win. + +You're behaving +non-cooperatively. + +You're competing to win. + +So basically what the insights +of game theory are that all + +the tools we used strategically +to make + +decisions in playing games can +actually be used in modeling + +how firms compete +non-cooperatively in + +oligopolistic market. + +The key insight is that each +firm will develop a strategy. + +Just as when you're playing +chess you have some strategy + +going in, firms develop +a strategy. + +And that based on that strategy +they will determine + +their behavior. + +And what is going to determine +that behavior is going to be + +how firms' strategies combine to +determine a market outcome. + +When firms come in with +different strategies, or when + +a bunch of firms with strategies +come in to compete + +with each other, what determines +the market outcome. + +And what that's going to depend +on is something we call + +an equilibrium concept. + +Which is how do we measure-- + +essentially the equilibrium +concept is in game theory + +terms, think about how +do we determine + +when the game's over? + +How do we determine when +we've decided on the + +outcome of the market. + +What's the equilibrium +concept? + +So when you're reading the rules +of a new game the first + +thing you look for is how +do you decide who wins. + +That's kind of like what the +equilibrium concept is. + +It's what determines whether +the game has ended. + +What determines whether you've +reached equilibrium. + +Where you've reached a point +where the market is stable and + +therefore the game has ended. + +Not ended in the sense the firm +shut down, but ended in + +the sense that you know what +everybody's doing. + +So it's not quite like +winning or losing. + +It's more just like what +determines when you're at the + +point where that market +is at equilibrium. + +Now the most famous concept is +due to John Nash, who many of + +you heard of from the movie and +book A Beautiful Mind, and + +that's called the Nash +Equilibrium. + +A Nash equilibrium is the point +at which no firm wants + +to change its strategy +given what the + +other firms are doing. + +I'm going to say that again. + +A Nash equilibrium is the point +where no firm wants to + +change its strategy given what +the other firms are doing. + +It's a little bit bizarre, +but we'll work it out. + +In other words, more formally, +the idea is that holding + +constant, given the strategies +all your competitors use + +there's nothing that I can do +to raise my profits further. + +Given the strategies all my +competitors are playing, + +there's no strategy I can choose +that will make me more + +profitable than the +one I'm choosing. + +And likewise for every player +in the market that will turn + +out to be true. + +So have players sitting +around a game board, + +going around the circle. + +Each player says, given what I +know each of the rest you are + +doing, I'm doing the +best thing I can. + +And they go around the circle +and everybody says, OK, I'm at + +that point. + +You've reached a stable +Nash equilibrium. + +This was named, of course, +for John Nash. + +You all know the story +of John Nash. + +He was a famous, actually +mathematician. + +We use his tools in economics, +but he was a mathematician. + +Developed these incredible +theories, and then developed + +schizophrenia, went crazy. + +But not before he developed +some of the most important + +concepts in both mathematics +and economics. + +The most important is the +Nash equilibrium. + +Now the best illustration we use +of the Nash equilibrium is + +an example that we refer to +as the prisoner's dilemma. + +And many of you will be familiar +with this from more + +popular reading you've +done in economics. + +But let me just go through it +because it's important to + +understand it. + +The prisoner's dilemma. + +The prisoner's dilemma the title +comes from the old way + +they used to make +police movies. + +Where the idea is you catch +two guys at a crime. + +You can't put them away unless +one of them fesses up. + +So what you do is you put them +each a separate room. + +And you say to the one, +your buddy's cracked. + +He's going to he's going to +sell you down the river. + +You better, I'm using all my +'50s analogies, he's going to + +put you away for good. + +But if you admit that he's +guilty and he did the crime, + +we'll let you off with +a light sentence. + +Then they go to the other room +and say the same thing to the + +other guy hoping they'll both +rat on each other and they'll + +both get a sentence. + +So basically the idea is, let's +say that you walk into + +each room and you say to each +person, look, we have enough + +evidence right here, and you +show them, to send you each to + +prison for a year. + +We would have enough evidence +to send you each to + +prison for a year. + +But we aren't sure about +this other thing. + +If you'll admit that your friend +did this other thing, + +then he'll go for five years +and you'll go free. + +And then we go to the friend +and say the same thing. + +If you'll admit that your friend +did the other thing + +he'll go five years and +you'll go free. + +But if they both admit then they +both go for two years. + +So if they both admit, they +both go for two years. + +Now the way to write this +down, what we do here to + +explain this, is we write down +what we call a payoff matrix. + +So write down a payoff matrix. + +So the idea is we have +prisoner A here + +and prisoner B here. + +And they each have an option. + +They could remain silent +or they can talk. + +Silent or talk. + +Now if they both remain silent, +if they both say I + +would never rat out my friend, +I'm happy to go to jail for a + +year rather than rat out my +friend, then they each get one + +year in jail. + +a equals 1, b equals 1. + +However if prisoner A rats out +his buddy and prisoner B + +chooses not to rat out his +buddy, then A gets-- + +so I'm sorry, if prisoner +A talks and + +prisoner B remains silent. + +Prisoner A talks, prisoner B +remains silent, then A gets + +zero but B get five +years in prison. + +On the other hand, if prisoner +B rats out his friend, but a + +prisoner A is true and doesn't +say anything, then prisoner A + +is going to get stuck with five +years and prisoner B is + +going to get nothing. + +And if they both rat each +other out then they + +both get two years. + +So people understand +the payoff. + +Are there questions about +the set-up here? + +This is complicated so +got to make sure you + +understand the set-up. + +Now, could someone tell me, if +A and B could truthfully + +cooperate, what would be the +optimal cooperative strategy? + +Yeah. + +AUDIENCE: You both +go for a year. + +PROFESSOR: Right, you'd +both be silent. + +So the optimal cooperative +strategy is clear, which is to + +both be silent. + +So if the cop said, you know +what, we'll let you guys get + +together and discuss what +you want to do first-- + +which the cops would never be +stupid enough to do-- but if + +they did and the guys can trust +each other, then that's + +the optimal cooperative +strategy. + +What we call optimal in the +language of game theory, we + +call that the dominant +strategy. + +A dominant strategy is the best +thing to do no matter + +what the other guy does is +the dominant strategy. + +So the dominant cooperative +equilibrium strategy is to + +both stay quiet. + +But what's the dominant, +non-cooperative strategy? + +What is the dominant +non-cooperative strategy? + +So the ways with dominant +strategy, we run through. + +Take prisoner A, ask +the following. + +The dominant strategy is, is +there a strategy that makes + +him better off regardless +of what B does. + +Is there a strategy that makes +A better off regardless of + +what B does. + +Let's go through. + +If A remains silent, if B +remains silent he gets a year. + +If B talks he gets five years. + +Now compare that to prisoner +A strategy of talking. + +Well if he talks he's better off +than if he doesn't talk, + +if B's remaining silent. + +If he talks he's better +off than if he + +doesn't talk if B talks. + +That is regardless of what B +does, he's better off talking. + +Regardless of what B chooses to +do, his dominant strategy + +is to talk. + +Because if B is silent, he's +better off if he talks. + +If B talks he's better +off if he talks. + +So matter what B chooses to do, +A is better off talking. + +What about B? + +Well B, by the same logic, +is always better + +off talking as well. + +No matter what A chooses +to do, B is + +better off if he talks. + +So where do we end up? + +What ends up as the +Nash equilibrium? + +The Nash equilibrium is that +both prisoners talk. + +The dominant strategy for both +prisoners is to talk. + +And they both end up worse off +than they could have if they + +could have cooperated. + +So the dominant non-cooperative +strategy is to + +both talk, even though if they +could get together they'd be + +better both not talking. + +And this is basically how +game theory works. + +Game theory math gets +incredibly hard. + +And if you're interested, +14.12 is one of our most + +popular undergraduate courses, +game theory. + +It's a great course where you +take this and go run with it + +for a whole semester. + +It gets very complicated +mathematically. + +But the basic idea in game +theory is pretty + +straightforward, which is just +ask, are there dominant + +strategies that can be played +by each player. + +If each player has a dominant +strategy and those dominant + +strategies lead to a Nash +equilibrium then you're done. + +Here we're in a Nash +equilibrium. + +Why are we in a Nash +Equilibrium? + +Because given that A has talked, +B's strategy, which is + +talking is the optimal +thing to do. + +Given that B has talked, A's +strategy which is talking is + +the optimal thing to do. + +So given what the other person's +doing, each person is + +doing the right thing. + +So you're in Nash equilibrium. + +Given that B has chosen +to talk, A is talking. + +That's the profit maximizing +thing to do. + +Given that A is talking, +B is talking. + +That's the profit maximizing +thing to do. + +So given the strategy the other +player's chosen that's + +an equilibrium. + +Yeah. + +AUDIENCE: If they both talk and +got 10 years would that be + +the Nash equilibrium. + +PROFESSOR: No if they both +talk, the 10 years only + +happens if one talks and +the other one doesn't. + +AUDIENCE: No, I mean +like, [INAUDIBLE]. + +PROFESSOR: Oh, if they +both got 10 years? + +So let's ask that. + +Let's change this. + +Now let's just rework it. + +So now what's A's choice? + +Well A if he talks +and B's silent, + +then he's better talking. + +But if he talks and B talks, +he's worse talking. + +So then what he does depends +on what B does. + +What B does is going to +depend on what A does. + +And we can't obviously see the +Nash equilibrium here. + +Because there's no dominant +strategy. + +What you do depends on what +the other person does. + +So there's no dominant +strategy. + +Dominant strategies only occur +if there's something that you + +should do no matter what +the other person does. + +So in this case were these are +both 2, there is a dominant + +strategy, It's to talk. + +If those are both 10 there's no +longer a dominant strategy + +so we can't quickly get +the Nash equilibrium. + +It's a good question. + +Now this is not just a cute +example that you can use for + +prisoners, but actually +explains firm + +behavior in many contexts. + +So the best example I like to +think of of this is to think + +about advertising. + +So imagine if Coke and Pepsi, +and imagine a world where + +Pepsi was as popular as Coke. + +That should never happen. + +Coke's way better. + +But imagine that +was that world. + +So imagine a world where if +there's no advertising then + +basically Pepsi and Coke would +split the market 50-50. + +Imagine that set up. + +So if Pepsi and Coke could agree +not to advertise they'd + +split the market 50-50. + +However, it's going to turn out +that while that may be the + +dominant cooperative outcome, +that's not the dominant + +non-cooperative outcome because +each firm is better + +off advertising if the other +one doesn't, or regardless. + +So for example, imagine the +following payoffs matrix. + +I'm just making this up. + +But here you have Pepsi and +here you have Coke. + +And imagine the payoff matrix. + +And the payoff matrix is if they +don't advertise, so Pepsi + +can choose not to advertise, +or it can advertise. + +So if they both don't advertise +Pepsi gets 8 and + +Coke gets 8. + +I don't know what 8 is. + +8 is billion dollars. + +I'm just making up numbers +here, doesn't matter. + +So $8 billion each. + +If they both do advertise then +they still end up splitting + +the market. + +Because basically they're just +as good as each other. + +So they both spend all the money +advertising and just + +back up where they would have +started, except they've wasted + +all this money in advertising. + +So if they both advertise they +each earn $3 billion instead + +of $8 billion. + +That is, they each +split the market. + +They end up back where they +would have started but they + +pissed away a bunch of money +advertising along the way. + +However if Coke advertised +and Pepsi doesn't. + +Then almost everybody sees Coke, +Coke, Coke everywhere + +and is like, Pepsi? + +Never heard of that. + +Coke makes $13 billion and +Pepsi loses $2 billion. + +And likewise if Coke doesn't +advertise but Pepsi does, + +people are like, I've +never heard of Coke. + +I'm going to drink Pepsi. + +So Pepsi makes $13 billion and +Coke makes minus $2 billion. + +Once again I just made numbers +here so it would work, but + +these aren't real +world examples. + +So once again we can see there +is a dominant cooperative + +strategy, which is +they both should + +agree let's not advertise. + +But if they can cooperate, then +in fact what's the Nash + +equilibrium? + +Let's work it through. + +And there's no shortcuts here. + +You've just got to work +this through. + +Let's look for Pepsi. + +Well Pepsi says if Coke doesn't +advertise I'm better + +off advertising. + +If Coke does advertise, I'm +better off advertising. + +So my dominant strategy +is to advertise. + +Coke says, well gee, if Pepsi +doesn't advertise I'm better + +off advertising. + +I make $13 billion instead +of $8 billion. + +If Pepsi does advertise I make +$3 billion instead of negative + +$2 billion. + +So I'm better off +advertising too. + +So my dominant strategy +is to advertise. + +So for both firms the dominant +non-cooperative + +strategy is to advertise. + +So they both advertise and you +end up in this equilibrium. + +It's an example of how a +non-cooperative equilibrium + +can lead to what we call +a race to the bottom. + +You can think of it as +a race to the bottom. + +In other words, if they could +cooperate they could just be + +better off. + +But because they can't trust the +other, there's this race + +to the bottom where they +both end up worse off. + +This is pretty striking. + +I thought they brought this out +well in A Beautiful Mind, + +both the movie and the book, +which is that all we've + +learned about economics +so far is that + +competition is good, right? + +Competition is beneficial. + +Well here's a case, where in +fact, at least in the firm's + +perspective, competition +is bad. + +If they could just get together +and cooperate they + +could make more money. + +Now, in fact, this example +is not so far-fetched. + +I don't know when it +started but it + +was during your lifetimes. + +When you were young, hard +liquors, scotch, bourbon, + +whisky, et cetera, did not +advertise on television. + +You never saw a Johnny Walker +ad or anything on television + +until, I don't know when +it changed maybe five + +or six years ago. + +Maybe 10 years ago, +I don't know. + +But certainly in +your lifetimes. + +That was not by government +regulation. + +Many people thought there +was a government + +regulation, they couldn't. + +That was not. + +That was a cooperative +equilibrium where the makers + +of hard liquors got together and +agreed not to advertise on + +TV. And they said it was in +the "public interest" yada + +yada yada, but that wasn't. + +It was just they recognized the +benefits of cooperating + +and not wasting money +advertising on TV and + +competing with each other. + +Well that broke down some +number of years ago. + +And now you see whiskey ads +and scotch ads and other + +things on television. + +And they've moved to this +non-cooperative equilibrium + +where they're all losing money +by having this advertising. + +So that's in advertising. + +For me, once again, this is a +hard thing, what intuition + +works for you. + +For me the intuition works best +maybe from my scars from + +my dating life is thinking +about personal decisions. + +So imagine that there's some +girl named Allison. + +And Allison has a potential +problem with her boyfriend. + +They've had a fight and now +she's deciding whether or not + +to make up or break up. + +Now we can think of this just +like Coke and Pepsi. + +Allison is going to be thinking, +well gee, if he + +wants to make up with me and I +want to make up with him then + +we're both better off. + +But if I want to make up with +him and he doesn't want to + +make up with me, that makes me +look like a total idiot. + +Whereas if I break up with him +preemptively, yes it would be + +sad if he wanted to stay with +me, but at least if he wanted + +to break up with me +I look better. + +So she preemptively breaks +up with him. + +John, her boyfriend, thinking +the same thing, behaves in + +exactly the same way. + +So it could be that even though +they both would be + +better off if they just said, +look the honest truth is, + +we're both wrong, let's make +up and we'll both be happy. + +Because they're so afraid of +being the one being dumped, + +they end up breaking up. + +Now we all know of examples +like this from life, where + +people stupidly if they could +have just cooperated had a + +better outcome because they're +so afraid of being left with + +the short end of the stick, +because they don't cooperate + +you end up with the worst +outcome for both. + +That's an example of +a non-cooperative + +equilibrium in real life. + +Now in real life there is one +aspect of oligopolistic + +non-cooperative equilibria +that allow them to be + +enforced, however. + +That allow you to overcome +the prisoner's dilemma. + +There's one thing that allows +you to overcome the prisoner's + +dilemma and that's +repeated games. + +Repeated games can +help you overcome + +the prisoner's dilemma. + +Now let's take the Coke and +Pepsi example and let's + +imagine that they're making +the advertising + +decision every period. + +Every period they +have to make an + +independent advertising decision. + +They can advertise or not +advertise every period. + +And imagine Coke says to Pepsi, +I've got the following + +deal for you. + +I commit to not advertise as +long as you don't, but the + +minute you advertise I'm going +to advertise forever. + +So as long as you don't +advertise I won't. + +But if you ever run an ad, the +bet's off and I'm never going + +to cooperate with you. + +I'm going to advertise +forever. + +Let's think about Pepsi's choice +in period one if Coke + +presents them with this deal. + +Let's think about Pepsi's choice +if Coke presents them + +with this deal. + +Well one thing is they could +say, ha ha, great Coke, good + +job trusting me. + +I'm going to screw you in +advertising period one. + +So Pepsi could say, great, +Coke's laid down arms in + +period one. + +I'm going to go and advertise. + +I'll make $13 billion in period +one because Coke's + +wimped out. + +And then I'll make $3 billion +forever after, because forever + +after we're both going +to advertise. + +But at least I' beat them +up that first period. + +However, if Pepsi says, wait +a second, if Coke's really + +right, honest, then I can get +an equilibrium where we make + +$8 billion forever. + +And certainly $8 billion forever +a better deal than $13 + +billion one year and +$3 billion forever. + +So in fact if Coke's willing +to live up to that promise + +then that is a good deal. + +And actually we can turn this +non-cooperative equilibrium + +into a cooperative equilibrium +through the enforcement of a + +repeated game. + +Through the fact that this game +gets played over and over + +and over again you can enforce +a cooperative equilibrium. + +We can come back to +relationships again. + +If you're in a committed +relationship and you know that + +if I say it's your fault over +and over again, eventually + +person's going to leave. Then +people say gee, I'm willing to + +take some of the blame and not +always say it's your fault and + +we have a fight. + +Because I know that if I always +say it's your fault + +ultimately that will break the +relationship up and that makes + +me worse off then admitting it +was my fault some of the time. + +It's the same logic. + +Yeah. + +AUDIENCE: Is the point of the +game to make more than the + +other guy or to make as +much as possible? + +PROFESSOR: Make as +much as possible. + +That's a good point. + +I presume that the point is to +make as much as possible. + +I'm ruling out cut off your +nose to spite your face + +equilibria. + +So in other words, I'm assuming +the goals is to + +maximize profits not relevant +mark position. + +That's a good point. + +I should have made that +assumption clear. + +It's the assumption we're always +making whatever we + +confirm behavior is assuming +it's profit maximization. + +So repeated games can enforce +a cooperative equilibria, + +essentially. + +Even in a non-cooperative +set up. + +But it turns out this +only works if the + +game goes on forever. + +This only works if the game +is going to go on forever. + +So, for example, imagine that +Pepsi knows that in 10 years + +the US government is going to +ban the advertisement of + +sugared sodas. + +The US government is going to +finally say, look, people are + +too obese, no more advertising +sugary sodas. + +Pepsi knows this. + +In 10 years that's +going to happen. + +Well Pepsi's thinking, +gee, that means in + +year 10 I should advertise. + +In that last year I should +advertise because Coke can't + +punish me the next year because +no one can advertise + +the next year. + +So I know starting after 10 +years we're both in this + +equilibrium because +the government's + +going to enforce it. + +So in ninth year, right +beforehand, right before that + +government ban I should +advertise and Coke can't get + +me the next period because +they don't have the + +tool to punish me. + +Well Coke, of course, +knows Pepsi is going + +to behave that way. + +So Coke says, wait a second, +if Pepsi's going to behave + +that way then I better advertise +in the ninth period + +too or I'm going to get hit +with a minus $2 billion. + +So I'm going to advertise +in the ninth period too. + +Well Pepsi says, look, if Coke's +going to advertise in + +the ninth period for sure, I may +as well advertise in the + +eight period because Coke's +going to advertise in the + +ninth period for sure. + +And by the same logic you can +work it back that they'll both + +advertise right away and +you'll end up with a + +non-cooperative equilibrium. + +That is a repeated game that +does not enforce the + +cooperative equilibrium. + +Because by working that logic +backwards if it ends in some + +realistic time frame, then you +better off just breaking it + +now rather waiting for +that period where + +you're the one who loses. + +Yeah. + +AUDIENCE: [INAUDIBLE] + +what if Pepsi [INAUDIBLE]? + +PROFESSOR: Exactly. + +If they don't then you could +imagine that if Pepsi knows + +this and Coke doesn't, then +Pepsi's optimal strategy will + +be to cooperate to the next to +last period then go ahead and + +screw Coke and then +Coke will lose. + +But presuming symmetric +information, repeated games + +cannot enforce these equilibria +if they end. + +So this is just an incredibly +quick introduction to the fun + +that is game theory. + +We're going to go on now and do +more rigorous versions of + +these models. + +But this is just to get you +excited about the tools you + +can do with game theory +with fun examples. + +Game theory is about taking +these fun examples and + +thinking a lot harder +about a lot. + +What if there's asymmetric +information? + +What if the game ends long +enough in the future that + +you're willing to be patient? + +How far off in the future does +the game have to end to still + +enforce the cooperate +equilibrium? + +What if there are +three players? + +What if players move in +different orders? + +What if one player goes first, +the second player responds to + +that, is it different than if +they go simultaneously? + +These are all really interesting +issues that are + +very relevant to the real world +firm behavior that you + +learn about game theory. + +So this is just to whet your +appetite for that. + +Having done that we're going to +now turn, leave aside these + +more interesting dynamic issues +and focus on a specific + +example of a non-cooperative +oligopoly. + +Because, once again, this is +all fun intuitively, but we + +want you to be able to work +through a problem. + +And the way to work that through +is we're going to have + +to move to a specific, +simplified example. + +And the example we're +going to focus on is + +called the Cournot model. + +The Cournot model of +non-cooperative oligopoly. + +The way we're going to do this +here, is we're going to return + +to the example we had with +the prisoner's dilemma. + +But instead of just facing two +choices, talk or not talk, + +we're going to talk about firms +facing a whole continuum + +of choices. + +Firms choosing how much they +produce in a non-cooperative + +equilibria situation. + +So, for example, let's +take the example + +they use in the book. + +Let's imagine there's two +airlines that fly between New + +York and Chicago, American +and United. + +And let's imagine for simplicity +those are the only + +two airlines. + +Because of the hub and spoke +system we talked about last + +time, let's say all the gates in +Chicago that are available + +to come from New York are +taken by two airlines-- + +United and American. + +Those are your only two options + +flying New York to Chicago. + +And the question we want to ask +is, get in that world, how + +do United and American decide +how many flights to run and + +what price to charge? + +If they're monopolies +we'd know. + +If it was a perfect competition +we'd know, but how + +do they decide this +all oligopolistic. + +The way we figure this out is +by looking for the Nash + +equilibrium in this case, which +we also call Cournot + +equilibrium. + +Which is basically the quantity +is chosen by each + +firm such that holding +all other + +firms' quantities constant. + +So each firm chooses quantity +such that holding all other + +firm's quantities constant they +are maximizing profits. + +So I choose a quantity such +that holding all the other + +firm's quantities constant +I'm choosing a + +profit-maximizing quantity. + +And if each firm can choose a +quantity that makes the market + +function where this is met, +then you're in Cournot + +equilibrium. + +You're in Cournot equilibrium +when each firm has + +decided, I'm happy. + +It's the same as the +Nash concept. + +I'm happy with what I'm +producing given what everybody + +else is producing. + +If everybody feels that way +then you're in a Nash + +equilibrium or a Cournot +equilibrium. + +So to see this, this is not +immediately intuitive. + +Let me just talk you through +the steps of how + +you'd solve for this. + +How do you actually solve for +a Cournot equilibrium? + +So basically what are the +steps to solving? + +Step one for solving a Cournot +equilibrium is to create each + +firm's residual demand. + +So compute residual demand. + +We talked about residual +demand curves earlier. + +Which is, that's the demand for +my firm given the quantity + +absorbed by other firms +in the market. + +In this case it's quantities +absorbed by the one other firm + +in the market, but in +general you do this + +with multiple players. + +So first you calculate +residual demand. + +Then having computed your +residual demand you develop a + +marginal revenue function. + +You calculate your marginal +revenue which will be a + +function of other firm's +quantities. + +So your residual demand will +lead you to calculate a + +marginal revenue function. + +It's a function of other +firms' quantities. + +You then do the same, do one and +two for all firms. So for + +each firm you end up with a +marginal revenue function and + +a function of all the +firm's quantities. + +Step four is you have +n equations and n + +unknowns and you solve. + +So you develop a series of +equation where each firm's + +marginal revenue function is a +function of each other firms + +quantities. + +You get one equation like +that for each firm. + +That leaves you n equations +and n unknowns you solve. + +If you can solve it then +you reach equilibrium. + +If you don't have a solution +then there is no stable Nash + +equilibrium. + +But if you can solve that there +is a Cournot equilibrium + +and you solve for it. + +So what we're going to do here +is I'm going to illustrate + +this to you graphically today +and we'll work through some + +more of the math of +it next time. + +So we'll start by doing +this graphically. + +So let's start by considering +the case of American Airlines. + +Let's start with figure 16-1. + +Start by considering the case +of American Airlines. + +And let's say that the demand +curve in this market in our + +example we're going to do, +let's say that the demand + +curve is of the form p +equals 339 minus q. + +So there's 339,000 flights that +are demanded each month. + +Each month there are 339,000 +flights demanded + +in the whole market. + +So 339,000 people want to +go from New York to + +Chicago every month. + +And let's also assume the +marginal cost is $147. + +I don't know where Perloff came +up with these numbers, + +but let's just go with them. + +The specific numbers +don't matter. + +Now what would American Airlines +do if it was a + +monopolist? + +If American Airlines was a +monopolist, it would set + +marginal revenues which are 339 +minus 2q by the same math + +we did before. + +You just multiply it through +by q and then differentiate + +and you get 339 minus 2q +equal to the marginal + +cost which is 147. + +So if it was a monopolist it +would choose a quantity of 96 + +and it would choose +a price of $243. + +A prices of $243 which +we would just get + +out the demand curve. + +If the quantity is 96, +the price is $243. + +And that's what we see here. + +The marginal revenue curve +intersects the marginal cost + +curve at a quantity of 96,000. + +You then go up to the demand +curve to read off the price. + +Remember for a monopolist you've +got to still respect + +the demand curve. + +You get the demand curve +to read off the + +price, that's $243. + +That's what American would do if +they were monopolist. So if + +they were the only folks flying +New York to Chicago, + +they fly 96,000 people a month +at a price of $243,000. + +However, now let's say American +recognizes that + +United is in the market. + +And let's say American +recognizes that United is + +going to deliver some amount +of flights q sub u. + +They know American is going +to do some amount of + +flights q sub u. + +They don't quite know yet what +it is, but they know there's + +going to be some amount +of flights q sub u. + +So the residual demand for +American is q sub a equals + +total demand minus q sub u. + +That's their residual demand. + +So, for example, let's say that +American just guesses + +that United will fly +64,000 passengers. + +Let's say Americans says, look, +I just know, I've got + +some corporate spy who's told me +that United will fly 64,000 + +passengers. + +So what you want to do is then +you just re-solve the problem + +but using residual demand. + +So then you say, well if United +is going to fly 64,000 + +passengers then my residual +demand is that price equals + +339 minus the quantity I sell, +q sub a, minus q sub u, which + +I think is 64,000, +which is 64. + +So my new residual demand is +p equals 275 minus q sub a. + +That's my new residual demand. + +Because I thought United is +going to sell 64,000. + +So instead of my demand +being 339 minus q, now + +275 minus q sub a. + +That's what's left. + +So if I use this as my new +demand function and re-solve, + +if this is my demand function, +my marginal revenues are then + +275 minus 2 qa. + +My marginal cost is the +same which is 147. + +So instead of my equation being +339 minus 2q equals 147. + +Now it's 275 minus +2qa equals 147. + +If I do that I'm going to get +a qa star of 64,000 flights. + +I'm going to say, well look, if +I was a monopolist I would + +have deliver 96,000 flights. + +But given that United is +delivering 64,000, that's it's + +going to be optimal for me +to also deliver 64,000. + +At 64,000 flights what's +my price going to be? + +Well my price is 275 minus qa. + +So my price is going +be to be $211. + +If I think United is delivering +64,000 flights then + +I'm going to deliver 64,000 +flights at a price of $211. + +So that's basically how American +would function. + +Now what's strange about this +is American doesn't know how + +many flights United is +going to deliver. + +There isn't such a thing. + +In fact, it's not like there's +not some rule which says we're + +going to go 64,000. + +United is trying to figure +this out too. + +So, in fact, simultaneously to +American making this decision, + +United is making the +same decision. + +And they're going through +the exact same math. + +They're saying, well gee, given +how much American flies, + +how much should we fly? + +They're going through +the same math. + +And in fact if we assume that +both firms have to face the + +same marginal cost and the same +demand curve, then in + +fact they're solving a +symmetric problem. + +They are also creating a +residual demand function, but + +instead of being qa equals d +minus qu, now United is making + +qu equals d minus qa. + +They're making a parallel +residual demand function and + +they are solving as well. + +And both firms, therefore, are +ending up with choices of + +quantities that depend on the +other firm's quantity. + +And in particular what they're +developing is what we call a + +best response curve. + +So figure 16-2, I skipped +over figure 16-2. + +This just illustrates what +happens when American thinks + +United is committing 64,000. + +Let's go through that +in one second. + +Get through it mathematically. + +This is an example where +American knows United is doing + +64,000 flights. + +So they say, well look, my +residual demand is essentially + +this new line d super r. + +And that's what I choose +on that new line. + +So that creates a new marginal +revenue curve, mr super r. + +That new marginal revenue curve +intersects marginal cost + +at 64,000 and that's why I +fly only 64,000 flights + +at a price of $211. + +So you see here is one example +of how given an amount United + +is flying, how American chooses +how much to fly. + +Questions about that graphic +that ties the math I did here? + +What figure 16-3 does is say, +look, we can actually do this + +for a whole host of possible +production levels + +by the other firm. + +And we can develop what we call +best response curves. + +Best response curves are, given +what the other firm + +does, what should I do. + +So, for example, American's best +response curve is given + +that-- so on the x-axis we have +how many thousands of + +flights American's passengers +are flying per quarter. + +On the y-axis how many thousands +of flights United + +passengers are flying +per quarter. + +So, for example, if American +decides to fly zero flights + +then United should fly +96 flights, right? + +Then United is a monopolist. +So that's the point on the + +y-axis, to 96,0 point +on the curve. + +With a 0 on the x-axis, +96 on the y-axis. + +If American decides to fly 0. + +United should fly 96. + +That's the monopoly case +we just solved. + +If American decides to fly +64, United should fly 64. + +That's the case we just +solved as well. + +Likewise, American's best +response curve is + +this steeper line. + +But it's the same thing. + +If United flies 0, American +should fly 96 then at 0 on the + +y-axis, 96 on the x-axis. + +So if United flies 0 American +should fly 96. + +If United flies 64, American +should fly 64. + +So you can actually, literally +trace out these curves asking + +at every single point, given +what the other guy's doing, + +what should I do. + +So we solved for two points +on this curve. + +We solved for the other guy +producing zero point, which is + +you produce 96. + +We solved for the other guy +producing 64 point which is + +you produce 64. + +That same math can be used +to solve for every + +point on this curve. + +Yeah? + +AUDIENCE: [INAUDIBLE] + +192 point. + +PROFESSOR: The 192 +point is it's the + +question is the following. + +At what point would American +produce zero. + +How much when United have to +produce for American to + +produce zero. + +Well they'd only produce +zero if United + +was producing 192,000. + +Only at that point would they +actually say, forget it, we're + +just going to produce zero. + +That's what the 192 +point means. + +Only if they knew United was +producing all that much would + +they just drop out +of the market. + +So that's the 192 +intersection. + +A backwards way to +read the curves. + +But the bottom line, is +essentially we can write these + +best response curves. + +They're basically the quantity +I'm going to produce given the + +quantity the other +firm produces. + +And the key thing is +that these are + +symmetric in this example. + +Since the costs are the same +and they both face the same + +market demand then these +curves are symmetric. + +What that means is that these +curves are having figured out + +one you can automatically +draw the other. + +A trick for solving these +problems is that if you have a + +symmetric Cournot equilibrium +you don't need to calculate + +the math to find each firm's +best response curve. + +Once you calculate one you know +the other firm's just a + +complement of it. + +So having calculated American's +best response curve + +we could have automatically +drawn the United best response + +curve as a complement of that. + +The other key point is by +drawing this diagram we can + +see the Cournot equilibrium. + +Remember Cournot equilibrium. + +Cournot equilibrium is where +I'm happy with my quantity + +given what the other +firm's doing. + +Given what the other firm's +doing I can't + +make any more money. + +Once again, I don't care about +market share, I just care + +about money. + +So given what the other +firm's doing I can't + +make any more money. + +Well that happens +at 64,000 each. + +Because when American is +producing 64,000, United is + +happy to produce 64,000. + +That's their profit +maximizing choice. + +If United is producing +64,000 American's + +happy to produce 64,000. + +That's their profit +maximizing choice. + +So that point of each producing +64,000 we are in a + +Nash or Cournot equilibrium. + +Both firms are happy given what +the other firm is doing. + +Both firms are profit maximizing +given what the + +other firm is doing. + +Now basically, for example, +another way to look at this is + +that you're only in equilibrium +if you're on both + +firms' reaction curves. + +So, for example, American +might say, look the + +equilibrium I like is +where I do 96,000 + +flights and you none. + +So the equilibrium I like is on +the x-axis the point 96, 0, + +where I do 96,000 flights +and you United do none. + +United says, however, no that's +not optimal for me. + +Because if you're doing +that, then you're + +charging a price of $243. + +So there's money to +be made for me. + +I can come in and start stealing +some of your flights. + +So that's not an equilibrium +from my perspective. + +Might be an equilibrium +from your perspective. + +You're delighted you're a +monopolist. But not from my + +perspective. + +At that price I'll +come in and start + +stealing some your business. + +And I'm going to start stealing + +some of your business. + +As I steal your business you are +going to have to move up + +your best response curve because +your residual demand + +is shrinking. + +And you'll only reach +equilibrium when you're both + +happy with the outcome. + +If only one firm is happy with +the outcome the other firm can + +always change its behavior, +raise its price up or down or + +its quantity up or down to +change the market share and + +change the outcome. + +So equilibrium will only be when +you're at both firms best + +response curves. + +You'll only be at both firm's +best response curves where + +they intersect. + +Let's stop there I'm going +to come back next time. + +Jessica we should have the +same handout next time. + +Let's make sure this figure +is in the handout + +next time as well. + +And we'll come back and talk +about this last figure and + +we'll do the math behind +it as well. \ No newline at end of file diff --git a/eGSXsaJ-BlY.txt b/eGSXsaJ-BlY.txt new file mode 100644 index 0000000000000000000000000000000000000000..a6ac49c1ab583c715a670a5ebadc531ebd14e770 --- /dev/null +++ b/eGSXsaJ-BlY.txt @@ -0,0 +1,2949 @@ +The following +content is provided + +under a Creative +Commons license. + +Your support will help MIT +OpenCourseWare continue + +to offer high quality +educational resources for free. + +To make a donation or +view additional materials + +from hundreds of MIT courses, +visit MIT OpenCourseWare + +at ocw.mit.edu. + +PROFESSOR: We're going to +cover hashing next time. + +Now we're Going to +focus on pset three + +because I heard +pset three is hard + +so we're going to look at the +code and try to understand it. + +AUDIENCE: This course is hard. + +PROFESSOR: I've tried +to make it easy. + +I really tried. + +How many people +recognize the code? + +Does this look familiar? + +One, two, three. + +Everyone else got +stuck on question one? + +I'm not going to give you +the answers to the psets. + +We are going to-- + +AUDIENCE: [LAUGHING] + +PROFESSOR: Sorry. + +We're going to look at +the code and understand + +what it does because once +you understand what it does + +you can understand +how to modify it. + +All right, before I do +that, any questions? + +And I might not answer +them right away, + +but I will keep them in mind +while I go through the code. + +Are there any +specific pin-points. + +AUDIENCE: The types. + +PROFESSOR: Yep. + +Covered in five minutes. + +Oh well. + +The first thing that +I want to talk about + +is sweep line algorithms. + +We're asking you to implement +the sweep line algorithm + +and we're giving you one +that is horribly inefficient. + +Suppose you have some line +segments that look like this. + +Sorry, drawing isn't. + +They look like this. + +And suppose you want to find +the intersections between them. + +Now let's figure out +what the algorithm + +that we gave you does. + +Did people look at +the trace for that? + +Not the good trace, the trace +that's output by the algorithm + +that we gave you. + +Does anyone understand +what that does. + +AUDIENCE: I kind of get it. + +PROFESSOR: OK. + +AUDIENCE: I think what it does +is it just hits through all + +the horizontal lines and it goes +through all the vertical ones. + +First it goes through +all the horizontal lines + +and what does it do with them? + +AUDIENCE: [INAUDIBLE]. + +PROFESSOR: They get bolded +in the visualizer which + +means they're added +to the range index. + +So one, add all the +horizontal lines. + +And two-- oh you said it goes +through all the vertical lines + +after that. + +Any idea what it does? + +AUDIENCE: It looks +for intersections. + +PROFESSOR: When he looks +at a vertical line segment + +you'll see some blue +square and you'll + +see some segments +that are green. + +This is a query +to the range index + +and the green segments +are the answers + +and the blue square is +the range that's queried. + +First add all the segments +to the range index + +and then do a query. + +In principle sweep +line algorithms + +have some geometric inputs. + +For example, a bunch of lines. + +And conceptually they +have this vertical line + +that they sweep across the plane +all the way from minus infinity + +to plus infinity. + +Now if you try to sweep +a line continuously + +from minus infinity to +plus infinity in code + +it might take forever. + +We don't really do it that way. + +The way we do it +in code is you know + +when something interesting +is going to happen + +and you only simulate what +happens to the sweep line + +at that point. + +In this case the sweep line +starts at minus infinity + +and then all the +horizontal segments + +are added to our range index. + +And then as the sweep line +goes across the plane, when + +it hits a vertical +segment a query happens. + +The only times when +the sweep line stops + +is first, at the beginning to +add all the horizontal line + +segments, and then every time +it hits a vertical line segment. + +We know this ahead +of time so we can + +compute a list of +all these coordinates + +of interesting things. + +And then we can sort them +and then go through them + +and simulate the behavior +of the sweep line that way. + +If you look at the code +listing at events from there, + +this is the gist of it. + +This is what it does. + +It compiles a list of events. + +The first key in each +event is the x, is that x? + +Yeah. x like this, y like this. + +The first case, the +x-coordinate of an event + +and by sorting +that list of events + +it will then process +them in order. + +Events from there is responsible +for looking at all the wires + +and compiling events. + +How does an event for a +horizontal layer look like? + +Can anyone tell me? + +Sorry, for a horizontal wire. + +AUDIENCE: It will run +across [INAUDIBLE]. + +PROFESSOR: First off it +looks like a list, right? + +It's a regular python list. + +And I will try to call it vector +so that we don't confuse it + +with a big list +of all the events. + +You said the first thing +is the leftmost point. + +Right? + +If this segment, for +example, starts at minus 100, + +this one starts at minus 95, +this one starts at minus 90, + +and this one starts at minus +50, by the way not to scale, + +then the leftmost +point is minus 100. + +Right? + +This is the first +element in the vector. + +And that's computed +on line four where + +it goes through +all the segments, + +looks at all the X-coordinates +and chooses the minimum. + +What's the next +thing in the vector? + +We don't have to understand why. + +We'll go through why in a bit. + +I'm just interested in what? + +AUDIENCE: Zero. + +PROFESSOR: Zero. + +Excellent. + +PROFESSOR: After that +there is a wire ID. + +Each wire gets a unique ID, +that's a number between zero + +and the number of wires. + +Say this is one, two, three. + +This is going to be one. + +And then I have the string add. + +And then I have the +actual wire object. + +What does the vector look +like for a query event? + +Sorry, what does it look +like for a vertical wire? + +I'm giving away +some of the answer. + +Bad, bad, bad. + +All right, vertical wire, +look at the code and. + +AUDIENCE: It keeps +the left [INAUDIBLE]. + +PROFESSOR: Of the wire. + +OK. + +And? + +AUDIENCE: It keeps the +x-coordinate [INAUDIBLE]. + +PROFESSOR: A vertical wire will +have the same X-coordinates + +for all the points +on the wire, right? + +I don't really worry about +which coordinate it is. + +This wire is at minus 50. + +The first element here +is going to be minus 50. + +What's next? + +AUDIENCE: A 1. + +PROFESSOR: A 1. + +OK. + +And suppose this is wire ID 4. + +I'm going to have 4. + +AUDIENCE: Query. + +PROFESSOR: Query. + +AUDIENCE: And the wire. + +PROFESSOR: And the wire. + +All right, what happens with +these in the init method, which + +is not shown in +the code listing, + +is after the list is put +together sort is called on it. + +These are all compared +and then reordered + +to be sorted according to +some ordering relationship. + +Does anyone know what +the ordering relationship + +is for Python lists? + +Yeah. + +AUDIENCE: It starts from +the first, from zero, + +and the next it goes to +sort the same with as X 1. + +PROFESSOR: OK. + +Say if I have 1, +2, 3 and 1, 3, 2. + +Sorry, and 2, 1, 2. + +He's going to look +at the first element + +and if they are different +than the one with the smaller + +element is smaller. + +1, 2, 3 as a vector, +sorry, as a list, + +is smaller than +2, 1, 2 as a list. + +If this guy becomes +one then they're equal. + +Then it has to go +to the next element, + +compare them and see if +they're different we have + +an answer, if not +we have to keep + +going all the way until +the end of the list. + +This is called +lexicographic comparison + +and this is the same ordering +that you have for the words + +in a dictionary. + +Right, if you think +of each letter + +as an element in a list +and the word is the list + +then this is how you look +up words in a dictionary. + +The reason events +look like this is + +so that sort would output +them in the right order + +for the next state. + +So, yes. + +AUDIENCE: Does that mean +all the horizontal wires, + +does that mean that they start +at same place even though that + +they don't? + +PROFESSOR: Yup. + +all the horizontal +wires will be sorted. + +All these add events will be +sorted before the query events. + +Yup, very good observation. + +This is what I'm +trying to achieve. + +That's why I have this +special value here. + +I go through some extra +effort to compute it. + +I had to write an +extra line of code + +so this is the +motivation for it. + +The first key in the +vector is the X element + +on the sweep line. + +I could've also had the +very large negative value + +that something that would +behave like minus infinity here + +and that would +work just as well. + +By computing the left edge I +don't have to deal with that. + +I don't have to worry of +whether my negative infinity is + +small enough, because if +it's not I will fail the test + +and that's bad. + +This is the x-coordinate at +which the sweep line stops + +and something happens. + +So if all the events are +different the x-coordinates + +then I have my +ordering, I'm done. + +Now what if I have two +events at the same time? + +For example, what if I +have two vertical wires? + +The x-coordinates are +going to be the same + +so I need to use something +else to break the ties, right? + +The first thing that I +use to break the ties + +is all add events +have a zero here + +and all the query +events have a one. + +And the point of +that is if I have + +two events at the +same x-coordinate, + +if I have a query +and an add, I want + +the add to happen +before the query. + +If this is the +same this is going + +to be different for +ad versus query. + +Does that make sense? + +This is how we order +events relatively + +to each other on the same line. + +Now suppose I have +these two wires, + +they're both vertical so they're +both going to be queries. + +They're both at the same index. + +I need something else, and +that other thing that I have + +is the wire ID which is +guaranteed to be unique. + +I know for sure the +comparison will stop here. + +And the comparison +had better stop here + +because if the comparison +gets all the way to here, + +wires aren't comparable so +the code is going to crash. + +It stops here because the IDs +are unique, everyone is happy. + +All right, do the events +make more sense now? + +To complete the +picture if you look + +at compute crossings, +lines nine and ten. + +Line nine goes through +the vector-- sorry, + +goes through the list of +events that have been sorted + +and processes them +in order so sort + +had better do the right job. + +And then it extracts the +x-coordinate, that's here, + +it extracts the event +type, that's here, + +and then it extracts +the wire from here. + +These guys really are just +there to help with the sorting, + +they're never read afterwards. + +AUDIENCE: Where are the +events actually sort? + +I thought they just +put into order. + +PROFESSOR: The events are +sorted in an init method that's + +not here. + +It's in the piece of +code but it's not here. + +And that may be a hint that +you don't want to change it. + +As in you don't need to. + +All right, events +look like this. + +Any questions about events? + +Everything make sense? + +Presumably when you write +your own sweep line algorithm + +you're going to come up +with your own events which + +are going to be different. + +You're going to change +these methods to add + +your own events to the list. + +And then it's going +to be sorted for you + +and then you're going to change +compute crossings to process + +your events in the way that +they should be processed. + +Let's look at the range index. + +What do we store +in a range index? + +AUDIENCE: The horizontal wires. + +PROFESSOR: Horizontal wires. + +Very good. + +What's the point of storing +horizontal wires in an index? + +AUDIENCE: That's when +you want to query, + +the area has a line through it. + +PROFESSOR: For the +algorithm that we gave you + +how does a query look like? + +Suppose I have this wire here +and I'm doing a query for it. + +AUDIENCE: Just ask to +list horizontal wires that + +are between that Y. + +PROFESSOR: Between this guy's +top and this guy's bottom. + +Right? + +AUDIENCE: Yeah. + +PROFESSOR: A query +would look like this. + +Basically all the +horizontal wires + +that have their y-coordinates +between this guy and this guy. + +Now if I have a wire that's +way up here or way down here + +I know for sure that it's not +going to intersect this wire. + +Right? + +I don't care about it. + +The range index helps +me eliminate some wires. + +Now, will the range index +eliminate all the wires + +that don't intersect +with this wire? + +No, OK. + +Why not? + +AUDIENCE: Well in +this code it doesn't. + +PROFESSOR: OK, in +this code it doesn't. + +We're only talking +about this code, + +I'm not talking about +the solution code + +that you guys have to implement. + +AUDIENCE: It doesn't +because it never + +removes the horizontal wires. + +PROFESSOR: OK. + +What's an example of a +query that would give me + +some wires that don't +intersect my wire? + +AUDIENCE: Like if they're +in between the y-axis, + +they're, yeah but +they're not actually. + +PROFESSOR: OK. + +So you mean. + +AUDIENCE: Yeah. + +AUDIENCE: Negative infinity +and infinity on the x-axis + +would give you a bunch of +wires and not many of them + +will intersect with +the vertical wires. + +AUDIENCE: If the end were a +vertical wire, [INAUDIBLE]. + +PROFESSOR: OK. + +I understood this because +it matches what I drew. + +I didn't understand the +minus infinity plus infinity. + +AUDIENCE: Well if you think +about the x-axis on the bottom, + +if you go from all the way +on the left to all the way + +on the right you're going to get +a whole bunch of wires that are + +short that-- + +PROFESSOR: Are you +talking about one wire + +that's like that, or many? + +AUDIENCE: If you're grabbing +from your range index. + +PROFESSOR: The range index +has horizontal wires in it. + +AUDIENCE: Right. + +AUDIENCE: Are you assuming +that they're all short? + +AUDIENCE: Yes. + +But it's not necessarily true. + +Some of them will be short. + +PROFESSOR: You're saying a lot +of short horizontal lines-- + +you mean like this, right? + +AUDIENCE: Yeah. + +PROFESSOR: OK. + +That's what you mean. + +AUDIENCE: You have +one intersection and-- + +PROFESSOR: A ton of +non-intersections. + +AUDIENCE: Exactly. + +PROFESSOR: OK, cool. + +Thank you. + +Doing a range query +on this can give me + +a lot of false positives. + +That's why after +I get them I have + +to make sure that +they intersect and I + +can't just blindly output them. + +These are bad false positives, +these are bad false positive. + +Now let's look at how +the range index works. + +Can anyone remind me of +what the range index does? + +It's a data structure, right? + +And it has some operations. + +What are the operations for it? + +AUDIENCE: It returns +everything between two values. + +PROFESSOR: You have a list +operation where you give it + +two values and it will return +everything inside the index, + +in the interval between +those two values. + +What else can I do? + +AUDIENCE: It can also +tell you how many. + +It returns those keys +and how many there are. + +PROFESSOR: I have +the count and you + +said that I have some +things in the index. + +Right? + +How do I get them in there? + +These are queries, +I need updates. + +AUDIENCE: Add and remove. + +PROFESSOR: For the code +that they gave you, + +what is the running time for +each of these operations? + +AUDIENCE: It would be +constant had to be removed. + +PROFESSOR: OK. + +Add calls the pend. + +Right? + +So that is constant. + +I will agree there. + +AUDIENCE: To remove it you +had to shift everything. + +PROFESSOR: Yep. + +Let's start with an example. + +Say I have these keys +in my range index. + +5, 8, 11, 13. + +Suppose they're magically +inserted in this order. + +If I want to remove two, +since this is an array + +I have to shift +everything to the left. + +AUDIENCE: Yes. + +PROFESSOR: So that's. + +AUDIENCE: Order and time. + +PROFESSOR: OK. + +How about list and counts? + +What's the running +time for counts? + +How does count work? + +AUDIENCE: It's not just +through all of the keys. + +PROFESSOR: Count goes +through everything and-- + +AUDIENCE: It has to +be order [INAUDIBLE]. + +PROFESSOR: Cool. + +Count goes through all +the keys, evaluates + +the predicate that checks +whether they're in the range + +and then it adds up one to +the sum for the right place. + +How about list? + +AUDIENCE: Also [INAUDIBLE]. + +PROFESSOR: OK, that's +a list comprehension. + +The code is a bit tricky, +but it pretty much + +does the same thing. + +It goes through the list +and it puts all the keys + +that are in the +interval in the list. + +Now let's look at +another version + +on the next page of our range +index that is slightly better. + +What's the rapid +variance for this? + +How is it different +from the first one? + +AUDIENCE: Sorted already. + +PROFESSOR: Sorted already. + +Very good. + +The keys look exactly like this. + +Right? + +What is the running time for-- +let's start with add or remove, + +what's the running time +for add and remove? + +AUDIENCE: N, order of N. + +PROFESSOR: Why is it order of N? + +AUDIENCE: No, oder log N. + +PROFESSOR: Why is +it order log N. + +AUDIENCE: Because if it's sorted +you can look in the middle + +and do a binary search. + +PROFESSOR: I can do a +binary search in order + +to find out where +I insert something. + +Right? + +But what if I want to +insert zero in this? + +AUDIENCE: Is it +log N plus order N? + +Does that make sense? + +Because you have to shift +all of the [INAUDIBLE]. + +PROFESSOR: Yeah. + +So worst case if I have +to insert zero here, + +I have to shift everything to +the right to make room for it. + +Right? + +So your first instinct was good. + +Order N. And questions? + +No more? + +Cool. + +How about remove? + +AUDIENCE: Order N. + +PROFESSOR: Order N. +Why is it order N? + +AUDIENCE: You have to shift +left everything to the right. + +PROFESSOR: Is this what +you were going to say too? + +Same reason as before, +if I want to remove 2 + +I still have to move +everything to the left. + +I can find the key that I +want to remove very fast + +but then shifting +things is still + +order N. OK how about count? + +How does count work? + +AUDIENCE: It's the +same thing, isn't it? + +AUDIENCE: Binary +search so it's log n. + +PROFESSOR: Binary +search, so it's log n. + +If I look at the +count there it's-- + +AUDIENCE: It's +not though, that's + +telling you how +many keys between. + +AUDIENCE: So it's a +simple subtraction + +to find the number +of keys between. + +PROFESSOR: Count calls +binary search twice + +and then it does a +arithmetic operation, yes. + +AUDIENCE: It would be log n +because with the count where + +the range is that's log n +because you have to actually + +sift through it, but +binary search you have two + +other operations and then +you just do a surprise. + +PROFESSOR: Yep, thank you. + +Very good. + +This is log n because of +good old binary search. + +How about lists? + +I think you were +thinking ahead of lists. + +How about lists? + +AUDIENCE: You have to list every +single thing that you read. + +AUDIENCE: You've got the +values you might potentially + +have to [INAUDIBLE]. + +AUDIENCE: Is it log n plus +the length of the list. + +PROFESSOR: Yeah. + +I was going to do a +nice long analysis + +and there's the answer. + +Log n plus, suppose you return +i values from the list, i. + +Why does this matter? + +If I have a range query from +minus infinity to plus infinity + +I have to create a new +list, copy all these keys in + +and return them. + +That's order n. + +I can't just say it's log n. + +On the other hand, if the +answers to my list queries + +are small, if +they're one element, + +then it's going to take log +n time to do a binary search + +and then order one to +produce the list if I + +have a constant size list. + +If I just say order n +I'm selling myself short. + +It's a lot better if I +want to have short queries. + +What would be the best possible +running time for lists? + +If I had a magic algorithm that +works as fast as possible would + +I be able to run +in order one time? + +AUDIENCE: No. + +PROFESSOR: Super fast +magic algorithm order one. + +No, why not? + +AUDIENCE: Because you still have +to find l and h in your array. + +PROFESSOR: Suppose I +have some other data + +structure, a super +magical data structure. + +AUDIENCE: You can do +searches in order one time, + +is what you're saying. + +AUDIENCE: You still have +to have the contents of it + +for what you're listing. + +It would have to be order i. + +PROFESSOR: Even if I +have a super magical data + +structure where I can do +everything that I want inside + +in order one time then +when I produce the output + +I still have to +write the output. + +This thing is +going to be omega i + +and I can't possibly do +any better than that. + +No matter what +running time you have + +for list it has +to include this i. + +Unless you're running time +is order i, in which case + +i is smaller or equal to n. + +Does this look right to you? + +There is a small +bug in this code. + +What if I do count of 4, 11. + +Binary search returns, +if there's a key + +there it will give me +the position of that key. + +And if there's no +key it will tell me + +where I should insert the +key if the key doesn't + +exist in theory. + +So if this is my array then the +positions are 0, 1, 2, 3, 4, 5. + +Count of 4, 11 would do a +binary search of 11 and see 4 + +and then it will do a binary +search for 4 and return 2. + +Right? + +Because if I want +to insert 4 I would + +have to put it here and then +shift everything to the right. + +And 4 minus 2 is 2 +therefore it's broken. + +AUDIENCE: Off by one block. + +PROFESSOR: Off by +one block, right? + +Well the interesting thing about +it is that I had this code, + +we actually shipped this +code between Saturday morning + +and Sunday evening and +it passed all the tests. + +As we go to the next +section keep in mind + +that this is broken +but it would still + +pass the test for our problem +and we'll see why in a bit. + +AUDIENCE: [INAUDIBLE]. + +PROFESSOR: Count of 4, 11. + +AUDIENCE: So +confined to them then + +it says that when +you're down 5, right? + +Four. + +PROFESSOR: Four. + +Binary search, if +it finds the key + +it returns the +position of they key. + +AUDIENCE: [INAUDIBLE] +4 divided by x, and 4, + +4 would it have had two? + +PROFESSOR: Yeah, because it +tells me where to insert it. + +AUDIENCE: OK, then it is. + +[INAUDIBLE] + +PROFESSOR: Well it +says 4 minus 2, right? + +The last line is high +index minus low index? + +AUDIENCE: Oh, well that's +wrong. [INAUDIBLE]. + +AUDIENCE: So are you saying that +it tells you where to insert it + +instead of actually +inserting it. + +PROFESSOR: Yeah. + +Binary search doesn't +insert the element. + +It just tells me this +is where you put it. + +And then if you look at add, +add inserts it right there. + +That's why binary +search is done that way + +so that that would work. + +AUDIENCE: Can I ask +a style question? + +PROFESSOR: Sure. + +AUDIENCE: The underscore +before binary search, + +is that like saying private? + +PROFESSOR: Yep. + +AUDIENCE: OK. + +AUDIENCE: Wait, what +does private mean? + +PROFESSOR: Private +means that it's not + +part of the public +interface of the class. + +If we're in a team and +we're working on something, + +if I mark a method as private +that means if you use my class, + +you're not supposed to call +it because I might change + +it's name, I might +delete it completely, + +I can do anything I want to it. + +But if the method is public, so +add, remove, list, and count, + +those are the API or the +public interface of the class. + +I guarantee that as long as the +blit range index class exists + +it's going to have an +add to remove a list + +and the conduct will behave +in exactly in that way. + +Once you have a class +with public methods + +you're not supposed +to change them + +because other people +might depend on them + +and that would make +other people unhappy. + +We said that this range +index holds wires. + +Right? + +So if you have these wires here +they're not really numbers. + +I know how to compare +numbers, I don't + +know how to compare wires. + +That's not something that's +readily comparable, right? + +We have to bridge the gap +between numbers or things + +that are comparable and wires. + +The way we do that is +the key wire pair class. + +If you look at key +wire pair class + +it has-- I will +write it as KWP here. + +So it has a key and the wire. + +Right? + +That's why it's a key wire pair. + +And if you look at the +comparison methods, + +lines 11 through 26, +but if you look at 11 + +through 13 pretty much +everything else is the same. + +Then comparisons are +done in a certain way. + +So the first +criterion is the key. + +If you have two key wire pairs +that have different keys, + +then the one with +the bigger key wins. + +Now if they have +the same key then + +this field called wire +IDs is used to break ties. + +So first key and then wire ID. + +What's the wire ID set to? + +And where? + +Where would you set a +field in a nice class? + +AUDIENCE: The constructor. + +PROFESSOR: In the +constructor, very good. + +Where is it set? + +Line number? + +AUDIENCE: 10. + +PROFESSOR: Line 10. + +So the wire ID uses the same +object IDs that we had earlier. + +So each wire has a unique +ID that's between zero + +and the number of wires. + +This works when I insert +my wires into the index. + +What's the key for +wires, by the way? + +Where are wires inserted into +the index in the algorithm + +that we have and what's the key? + +The algorithm that we gave you. + +Yes. + +AUDIENCE: The y-coordinates. + +PROFESSOR: The? + +Which one, I couldn't hear you. + +AUDIENCE: The y-coordinate. + +PROFESSOR: The y-coordinate. + +Can you tell me which line? + +The intuition is very good. + +You want the wires to be +keyed by the y-coordinate + +so that when you a range query +between this guy and this guy + +you get these wires. + +That's the intuition. + +Now what's the code? + +AUDIENCE: Line 13. + +PROFESSOR: Line? + +I didn't hear you well. + +Line? + +AUDIENCE: 13. + +PROFESSOR: 13. + +Wires are added to the +index when an event of type + +add is processed. + +Right? + +Line 12 says if +event type is add + +so that's probably what we want. + +And line 13 adds it to the index +and builds the key wire repair + +with the key, the +y-coordinate of the wire. + +Now let's look back +at the keys and see + +that we have two special +key wire repair classes. + +Key wire pair l and +key wire pair h. + +These don't want the wire. + +Why would I make a wire key +pair that doesn't want the wire? + +Why is that useful? + +AUDIENCE: You have the minimum +and maximum wire at ease. + +PROFESSOR: Very +good observation. + +The wire ID for the +low key pair looks + +like minus infinity and the +one for the high key pair + +look like plus +infinity as long as I + +don't have more than +a billion wires. + +What do these things not have? + +They don't have a wire. + +So if you look at key +wire pair l and h, + +if you look at the initializers +on lines two and eight, + +they only take a key +they don't take a wire. + +This is useful in +which situation? + +Where do I want to create +an index key that's + +not associated +with the real wire? + +AUDIENCE: When you want +to make the list when + +you want to do a query. + +PROFESSOR: When I do a query. + +Very good. + +If I'm querying, if I have +this vertical wire, which + +starts from minus +80 to plus 80 then I + +would like to make a low key +that corresponds to minus 80 + +and a high key that +corresponds to plus 80, + +but I don't have any wire with +a horizontal coordinate of 80. + +Right? + +A hackish solution +would be to make + +fake wires with +those coordinates + +but if I make fake wires God +knows where my system is going + +to break elsewhere. + +Instead the clean solution is +to have these key wire pairs + +so that when I insert +wires I have a wire + +and when I don't the +wire is set to none. + +And the wire IDs are +these special values, + +minus infinity +and plus infinity. + +What's cool about setting the +wire IDs to minus infinity + +and plus infinity? + +AUDIENCE: It's so that +if you have a y of 80 + +this y is at negative +infinity so it's + +going to take that y also +because its y value is + +[INAUDIBLE]. + +PROFESSOR: All right. + +Cool. + +If I have a real +key wire pair and it + +has a wire whose +coordinate is 80 + +this is going to be bigger +than a key wire pair + +l with coordinate +80 and it's going + +to be smaller than a key wire +pair h with coordinate 80. + +If you do a query +using this and this + +it's going to grab all the +wires with coordinate 80. + +Does this makes sense? + +So what's cool about +this in terms of coding? + +Do I have equal keys +in my range index? + +Do I have to handle +multiple equal keys? + +AUDIENCE: No because, +actually in this case yes. + +PROFESSOR: Do I? + +AUDIENCE: Because if you +have all the horizontal wires + +then it's possible +that you have two + +horizontal wires at the same-- + +PROFESSOR: If I have +two horizontal wires, + +say this guy here +and this other guy + +here, this guy here, what's +the key value pair for it? + +Key wire pair? + +Let's say the coordinate is +minus 95 and the wire ID is 2. + +The key wire pair is +they key is minus 95 + +and the wire ID is 2, right? + +AUDIENCE: Yeah. + +PROFESSOR: And then +for this other wire, + +suppose the wire ID is +10, the coordinate is + +going to be minus 95 then the +wire ID is going to be 10. + +So how are they +going to compare? + +AUDIENCE: Then that one +is less than that one. + +PROFESSOR: Yup. + +So even though I have two wires +with the same y-coordinates + +of the key as far as the +algorithm is concerned + +is the same, in +the implementation + +the keys are artificially +different because I introduce + +an artificial ordering on +the wires using that wire ID. + +In Which case would I have the +same key inserted in my index + +twice? + +Yes? + +AUDIENCE: [INAUDIBLE]. + +PROFESSOR: OK. + +If these two wires overlap, +say this guy ends here + +and this guy ends here, and if +I put their keys into the index + +they're still different. + +AUDIENCE: Only if they're +the same wire ID would + +they have the same-- + +PROFESSOR: OK, and when do two +wires have the same wire ID? + +AUDIENCE: If one of them +was negative infinity. + +PROFESSOR: Let's assume +that the infinities + +were in the right way. + +Yes? + +No? + +Wire IDs are unique. + +Every wire has it's own wire ID. + +Wires will never have +the same wire ID. + +So the only case +in which you have + +two equal keys in the index +is if you insert the same wire + +twice. + +Would you ever want to do that? + +Probably not. + +You're going to the same wire +twice from the range query + +and that's not useful. + +When implementing a data +structure for the range index + +we don't have to +deal with equal keys + +and that is nice because +that's less thinking. + +Now when we do a query, +will the keys in the query + +be in the range index? + +AUDIENCE: Not necessarily. + +PROFESSOR: How +would I do a query + +if I want to do a query +from minus 80 to plus 80? + +AUDIENCE: You grab all +the horizontal wires whose + +y-coordinates are-- + +PROFESSOR: You're thinking +in the range index. + +I'm thinking as the +client of the range index. + +So you have this +range index class, + +how would you issue a +query to the range index? + +AUDIENCE: The list on this page. + +PROFESSOR: OK. + +I would call the list method. + +And-- oh crap, I +thought I was going + +to avoid doing that today. + +l and h are keys, right? + +How do I construct my keys? + +AUDIENCE: Use key wire pair. + +PROFESSOR: Key wire +pair left of 80-- + +sorry low, and key +wire pair high of 80. + +So then I'm going +to get to these-- + +I don't have wires for +this 80 coordinate. + +Sorry, minus 80 to +80 because that's + +what the query looks like. + +I don't have wires +for these coordinates + +so I'm going to use +these special values + +and this one is smaller than +all the wires with coordinate + +minus 80 and this one +is bigger than all + +the wires with coordinate 80. + +Will these keys ever +be in the index? + +Nope, we're only using +them for updates. + +If you put this in +the index then when + +you're getting it back and you +try to get the wire associated + +with it you're +going to get none, + +your code is going to crash. + +If I have a query will +the keys in the query ever + +being the index? + +AUDIENCE: No. + +PROFESSOR: No. + +That means fewer border +cases to consider + +when implementing query. + +All the keys in the +range index are different + +and they keys in the query will +never be in the range index. + +AUDIENCE: When +you do the count l + +and h aren't in your range +index you have to count that. + +PROFESSOR: Yeah. + +In this case that's why the +code didn't fail any test. + +Because I'm not using numbers +I'm actually using this. + +So for the number +analogy this is + +equivalent to when I'm +doing a count of 4,11 that + +would get rewritten as count of +3, 99 and 11.01 and this works. + +This is what these +two values are doing. + +Except if you try +to do 0.99 and 0.01 + +that's brittle because you +might actually have those keys. + +All right, does this make sense? + +Any questions on this part? + +Nope? + +Yes? + +Yes. + +AUDIENCE: Is this thing +in a count off situation + +where you have a +gap in the wires + +but you still have a +[INAUDIBLE] associated with it + +as it's going through it. + +PROFESSOR: Sorry, +say that again. + +AUDIENCE: So with that +example right there. + +PROFESSOR: Yeah. + +PROFESSOR: Are you +worried about the fact + +that I'll have two equal keys or +are you worried about the fact + +that these wires are crossing? + +AUDIENCE: No that +they're not overlapping. + +You have a wire and you +have a wire coming down + +and you have another wire. + +PROFESSOR: OK. + +This is not going +to account for that. + +You have to write the +better sweep line algorithm. + +AUDIENCE: OK. + +PROFESSOR: What +I'm talking about + +now will make your +range index faster. + +Or it makes your range +index simpler to implement. + +AUDIENCE: OK. + +PROFESSOR: This is magic +behind the scenes that + +makes your code smaller. + +You still have to implement +the sweep line algorithm that + +makes sure that when +you a range query + +it will either return less false +positives or ideally no false + +positives. + +And then the code +will be faster. + +But then when you +do that, you'll + +see that it's still slow +because the range index + +that we have here isn't optimal. + +Why isn't the range index +here optimal, by the way? + +What can I improve about it? + +AUDIENCE: Add and remove. + +PROFESSOR: Add and remove. + +OK. + +We're using the comparison +model because it's + +convenient to use +the comparison model. + +You have complex objects to +implement those six methods + +that you see in key +wire pair and bam. + +You can do comparisons, you +can use any data structure + +or algorithm that assume +a comparison model. + +What's the penalty of +the comparison model? + +What's the problem with it? + +Yes. + +AUDIENCE: It will be +slower, or it will never + +be faster than the [INAUDIBLE]. + +PROFESSOR: Yup. + +If I want to do a +sort that is n log n. + +And if I want to do a +search that is theta what? + +AUDIENCE: [INAUDIBLE]. + +PROFESSOR: Now what are the best +bounds that they have for these + +if we can go outside +the comparison model? + +Just to see if you guys are +paying attention in lecture. + +So best running +time for sort if we + +don't have to use +the comparison model. + +AUDIENCE: n. + +PROFESSOR: n. + +OK. + +Best running time +for search if we + +don't to use the +comparison model. + +AUDIENCE: It's order +one with [INAUDIBLE]. + +PROFESSOR: Order +one, with hashing. + +Can you do any better than that? + +AUDIENCE: You can +code it as zero. + +[LAUGHING] + +PROFESSOR: Sort has +to output an array + +of elements so it can +be faster than order n. + +Search has to output yes +or no so it has to output + +something so it has +to be order one. + +So this is as fast +as it gets, we're + +definitely not going +to go faster than that. + +We have this extra +log n factor that we + +pay if we use the comparison +model if we don't collect + +more information about our keys. + +But in return we +have the convenience + +that all we have +to do is establish + +an ordering relationship. + +Does it make sense? + +Cool. + +Let's try to talk about +the list pseudocode, which + +you might have seen +on the pset before. + +And that's on the +last page here. + +I can't give you a +proof of why it works, + +but we can work together +to figure out how it works + +and get an intuitive +understanding. + +Let's get the keys +here and let's + +assume we're using a regular BSD +for implementing a range index. + +I'm going to put +my keys in a BSD. + +8, 3, 2, 5. + +OK. + +List those two things. + +LCA and no list. + +Right. + +What's LCA? + +Suppose I want to list all +the keys between one and six. + +First I'm going to call +LCA and get some answer + +and then I'm going +to call node list. + +What's the answer for LCA? + +OK. + +AUDIENCE: Node at three. + +Key value three. + +PROFESSOR: What is this? + +What's LCA? + +It's OK to give out an answer +to a dumb question on the pset. + +So LCA is lowest +common ancestor. + +Very good. + +It's the lowest common +ancestor of what? + +AUDIENCE: Subtree of values that +should be returned nodeless. + +PROFESSOR: So usually you +have two nodes in a tree + +and you want to return the LCA. + +If I want to find out the +LCA of 2 and 5, that is 3. + +If I want to find out the +LCA of 2 and 13, that's 8. + +Now if the keys are not in the +tree what does the LCA give me? + +AUDIENCE: It's +where they would be. + +PROFESSOR: It's where they +would be if they were inserted. + +Right. + +So 1 would be inserted here +and 6 would be inserted here. + +And then their LCA is indeed 3. + +What does that tell me? + +Why is that useful? + +AUDIENCE: You can cut off a +bunch of the rest of the tree + +so you don't have +to look at that. + +PROFESSOR: A bunch of, +or the rest of the tree? + +AUDIENCE: The rest of the tree. + +PROFESSOR: The rest of the tree. + +So if 1 is here and +6 is here, then I + +know that all the keys-- +sorry, so 3 is to the left of 8 + +so all the keys +to the right of 8 + +are going to be bigger +than 6, for example. + +Right. + +Because 6 is here +and it's under 8. + +I can throw this away. + +Now if this would be to +the left of something else, + +because 1 is here I +know that all the keys + +to the left side of that +thing would be smaller than 1. + +This subtree has to have all +the keys between 1 and 6. + +Yes. + +AUDIENCE: You don't +have to move 8, right? + +Where would you move 8? + +PROFESSOR: Yup. + +So we only look at the +subtree rooted at LCA. + +LCA is passed as an +argument to node list, + +and node list seems to +do sort of an-- this + +is a pre-ordered traversal. + +You look at the key, you +look at the left node, + +at the left subtree, you +look at the right subtree. + +Except there is some magic +there and in some cases + +it doesn't go and look. + +Let's see what would a good case +where it doesn't go and look + +like. + +Let's get the same tree. + +Suppose I want to do a +list between 4 and 11-- + +sorry between 4 and 10. + +We'll the LCA of 4 and 10? + +AUDIENCE: Eight. + +PROFESSOR: OK, so node list +would have to start here. + +Suppose I'm here and I go to 3. + +I know 3 is smaller than 4. + +Do I want to go left? + +Everything to the left +of 3 is smaller than 4. + +This entire subtree +can be pruned. + +Now suppose I'm on the right +side and I'm at the 11. + +11 is bigger than 10, +do I want to go right? + +So if 11 is bigger +than 10 I never + +want to go right +because everything + +to the right of that is bigger. + +OK so this is how pruning works. + +Now if I'm at 3, can I stop? + +I can't stop and exit completely +because on the right side of 3 + +I might have keys that +are bigger than three + +and that are in my interval. + +And in this example that +seems to be the case. + +Let's look very quickly +at the intuitive way + +of analyzing the +running time for this. + +Suppose I have my LCA +up here and suppose + +I go on a path from LCA +to L and then-- let's + +not worry about the right, +about h. h is somewhere here, + +the case is going +to be symmetric. + +When I go down the path, after I +go here would I ever want to go + +left? + +If this node is before +a right turn then + +I know that l is going to +be bigger than that node. + +Right? + +So I'm never going +to take a left turn. + +This subtree be pruned, +this subtree will be pruned, + +this subtree will be pruned. + +Now if I go right +here, what happens? + +AUDIENCE: It's node-- + +PROFESSOR: All +the nodes here are + +going to be between l and LCA. + +LCA is smaller or equal to +h so all these nodes here + +are guaranteed to be nodes +that come out in my list. + +All right, why am I doing this? + +I was saying before +that I absolutely + +have to have an +order i because I + +have to produce the output list. + +If we look at the +lines three and four, + +line four outputs a key right? + +Line four is definitely +order i and line three + +is an if condition +so we know for sure + +that line four is +only going to execute + +four keys that are +between l and h. + +This algorithm is going to +visit some nodes in the tree. + +For example, if I have a list of +4 and 10 it's going to visit 8, + +it's going to +visit 3, 5, and 11. + +And for some of the +nodes that are visited + +it's going to output them. + +Right this guy gets output +and this guy gets output. + +The nodes that are +outputs are order i. + +Those are already +covered in the i term. + +And in order to get the running +time what I need to know + +is, how many nodes do +I visit that are not + +part of the output. + +Because if I end up visiting +the entire tree then + +that's order n plus i. + +So order n. + +But if I only end up visiting a +few nodes outside of the output + +then that might be a lot better. + +And here I'm trying to +argue that I will only + +visit a few notes +the outside the path. + +In fact, for every +node I'm going + +to visit at most of the node +and the node at its left. + +And then everything to the right +of the path is between l and h, + +so everything to the right +is going to be output. + +Everything here is in +order i and everything here + +is visited in that output. + +And potentially everything +on the path as well. + +So what's the height of a +path in a binary search tree? + +Regular binary search tree? + +OK, and worst case. + +So worst case the +height is order n. + +But we usually call it height +because on average, at least, + +it's log n. + +It's somewhere +between n and log n. + +What is the running time for +lists in a binary search tree? + +If you buy this argument here. + +What is the running time? + +AUDIENCE: [INAUDIBLE]. + +PROFESSOR: You could say n plus +i and you're perfectly correct. + +But we can make it a bit better. + +What's the height of this path? + +AUDIENCE: h. + +PROFESSOR: H. What's +the running time? + +AUDIENCE: h plus i. + +PROFESSOR: OK. + +Cool. + +Does this make sense at all? + +Is this too complicated? + +AUDIENCE: That's the +running time for what? + +PROFESSOR: This is the +running time for lists. + +All right so, questions? + +Is this too far out? + +Did I lose you guys completely? + +Makes perfect sense. + +I like that. + +AUDIENCE: It's oder +n plus i because it + +could have up to any +nodes on it, right? + +PROFESSOR: Yup. + +AUDIENCE: And then it's +order i because you + +have to add that +[INAUDIBLE] of nodes anyway. + +It's order h. + +PROFESSOR: I'm saying that it's +a binary search tree of height + +h and if h is better +than n then I'm + +going to do much better +than n and that's + +why I'm putting that h there. + +AUDIENCE: OK, that makes sense. + +I think it's just a ltitle +confusing at that part, + +but the [INAUDIBLE] makes +sense because of course + +that's a smaller +node you're not going + +to look at the +left portion you're + +going to look at the +right because it's bigger + +than your smaller +[INAUDIBLE], right? + +So if you go to the +right, that means that-- + +PROFESSOR: Here I know that +l is on the left, right? + +So l is smaller than this key. + +Everything to the right of +this key is between l and LCA. + +LCA is smaller or equal to h. + +Everything here is +between l and h, + +so all the nodes here +are going to be output. + +All the nodes here count as i. + +AUDIENCE: OK. + +PROFESSOR: Now when I turn left +here, this is smaller than l. + +This is smaller than l +because l is on the right. + +This thing is +going to be pruned. + +So I will visit the parent, +this node, and that's it. + +I'm not going to look down. + +And this is how the +nodes look like. + +Everything that's to +the left of the path + +is not visited, everything +that's to the right it open. + +Any more questions? + +I hope you get it +right on pset then. + +Thanks guys. \ No newline at end of file diff --git a/f866lUTRXE4.txt b/f866lUTRXE4.txt new file mode 100644 index 0000000000000000000000000000000000000000..05a769a5ac45a8b20a56f3c6f8199bdb0d92a730 --- /dev/null +++ b/f866lUTRXE4.txt @@ -0,0 +1,427 @@ +align:start position:0% + +given a set of symbols and their + + align:start position:0% +given a set of symbols and their + + + align:start position:0% +given a set of symbols and their +probabilities Huffman's algorithm tells + + align:start position:0% +probabilities Huffman's algorithm tells + + + align:start position:0% +probabilities Huffman's algorithm tells +us how to construct an optimal variable + + align:start position:0% +us how to construct an optimal variable + + + align:start position:0% +us how to construct an optimal variable +length encoding by optimal we mean that + + align:start position:0% +length encoding by optimal we mean that + + + align:start position:0% +length encoding by optimal we mean that +assuming we're encoding each symbol one + + align:start position:0% +assuming we're encoding each symbol one + + + align:start position:0% +assuming we're encoding each symbol one +at a time no other variable length code + + align:start position:0% +at a time no other variable length code + + + align:start position:0% +at a time no other variable length code +will have a shorter expected length the + + align:start position:0% +will have a shorter expected length the + + + align:start position:0% +will have a shorter expected length the +algorithm builds the binary tree for the + + align:start position:0% +algorithm builds the binary tree for the + + + align:start position:0% +algorithm builds the binary tree for the +encoding from the bottom up start by + + align:start position:0% +encoding from the bottom up start by + + + align:start position:0% +encoding from the bottom up start by +choosing the two symbols with the + + align:start position:0% +choosing the two symbols with the + + + align:start position:0% +choosing the two symbols with the +smallest probability which means they + + align:start position:0% +smallest probability which means they + + + align:start position:0% +smallest probability which means they +have the highest information content and + + align:start position:0% +have the highest information content and + + + align:start position:0% +have the highest information content and +should have the longest encoding if + + align:start position:0% +should have the longest encoding if + + + align:start position:0% +should have the longest encoding if +anywhere along the way two symbols have + + align:start position:0% +anywhere along the way two symbols have + + + align:start position:0% +anywhere along the way two symbols have +the same probability simply choose one + + align:start position:0% +the same probability simply choose one + + + align:start position:0% +the same probability simply choose one +arbitrarily in our running example the + + align:start position:0% +arbitrarily in our running example the + + + align:start position:0% +arbitrarily in our running example the +two symbols with the lowest probability + + align:start position:0% +two symbols with the lowest probability + + + align:start position:0% +two symbols with the lowest probability +are C and D combine the symbols as a + + align:start position:0% +are C and D combine the symbols as a + + + align:start position:0% +are C and D combine the symbols as a +binary sub tree with one branch labeled + + align:start position:0% +binary sub tree with one branch labeled + + + align:start position:0% +binary sub tree with one branch labeled +zero and the other one it doesn't matter + + align:start position:0% +zero and the other one it doesn't matter + + + align:start position:0% +zero and the other one it doesn't matter +which labels go with which branch remove + + align:start position:0% +which labels go with which branch remove + + + align:start position:0% +which labels go with which branch remove +C and D from our list of symbols and + + align:start position:0% +C and D from our list of symbols and + + + align:start position:0% +C and D from our list of symbols and +replace them with a newly constructed + + align:start position:0% +replace them with a newly constructed + + + align:start position:0% +replace them with a newly constructed +sub tree whose root has the Associated + + align:start position:0% +sub tree whose root has the Associated + + + align:start position:0% +sub tree whose root has the Associated +probability 1/6 the sum of the + + align:start position:0% +probability 1/6 the sum of the + + + align:start position:0% +probability 1/6 the sum of the +probability of its two branches now + + align:start position:0% +probability of its two branches now + + + align:start position:0% +probability of its two branches now +continue at each step choosing the two + + align:start position:0% +continue at each step choosing the two + + + align:start position:0% +continue at each step choosing the two +symbols and/or sub trees with the lowest + + align:start position:0% +symbols and/or sub trees with the lowest + + + align:start position:0% +symbols and/or sub trees with the lowest +probabilities combining the choices into + + align:start position:0% +probabilities combining the choices into + + + align:start position:0% +probabilities combining the choices into +a new sub tree at this point in our + + align:start position:0% +a new sub tree at this point in our + + + align:start position:0% +a new sub tree at this point in our +example the symbol a has the probability + + align:start position:0% +example the symbol a has the probability + + + align:start position:0% +example the symbol a has the probability +1/3 the symbol B the probability 1/2 and + + align:start position:0% +1/3 the symbol B the probability 1/2 and + + + align:start position:0% +1/3 the symbol B the probability 1/2 and +the CD sub tree probability 1/6 so we'll + + align:start position:0% +the CD sub tree probability 1/6 so we'll + + + align:start position:0% +the CD sub tree probability 1/6 so we'll +combine a with the CD sub tree on the + + align:start position:0% +combine a with the CD sub tree on the + + + align:start position:0% +combine a with the CD sub tree on the +final step we only have two choices left + + align:start position:0% +final step we only have two choices left + + + align:start position:0% +final step we only have two choices left +B and the ACD subtree which we combine + + align:start position:0% +B and the ACD subtree which we combine + + + align:start position:0% +B and the ACD subtree which we combine +in a new sub tree whose root then + + align:start position:0% +in a new sub tree whose root then + + + align:start position:0% +in a new sub tree whose root then +becomes the root of the tree + + align:start position:0% +becomes the root of the tree + + + align:start position:0% +becomes the root of the tree +representing the optimal variable length + + align:start position:0% +representing the optimal variable length + + + align:start position:0% +representing the optimal variable length +code happily this is the code we've been + + align:start position:0% +code happily this is the code we've been + + + align:start position:0% +code happily this is the code we've been +using all along as mentioned above we + + align:start position:0% +using all along as mentioned above we + + + align:start position:0% +using all along as mentioned above we +can produce a number of different + + align:start position:0% +can produce a number of different + + + align:start position:0% +can produce a number of different +variable length codes by swapping the 0 + + align:start position:0% +variable length codes by swapping the 0 + + + align:start position:0% +variable length codes by swapping the 0 +and 1 labels on any of the sub tree + + align:start position:0% +and 1 labels on any of the sub tree + + + align:start position:0% +and 1 labels on any of the sub tree +branches but all those encoding x' would + + align:start position:0% +branches but all those encoding x' would + + + align:start position:0% +branches but all those encoding x' would +have the same expected length which is + + align:start position:0% +have the same expected length which is + + + align:start position:0% +have the same expected length which is +determined by the distance of each + + align:start position:0% +determined by the distance of each + + + align:start position:0% +determined by the distance of each +symbol from the root of the tree not the + + align:start position:0% +symbol from the root of the tree not the + + + align:start position:0% +symbol from the root of the tree not the +labels along the path from root to leaf + + align:start position:0% +labels along the path from root to leaf + + + align:start position:0% +labels along the path from root to leaf +so all these different encodings are + + align:start position:0% +so all these different encodings are + + + align:start position:0% +so all these different encodings are +equivalent in terms of their efficiency + + align:start position:0% +equivalent in terms of their efficiency + + + align:start position:0% +equivalent in terms of their efficiency +now try your hand at Huffman's algorithm + + align:start position:0% +now try your hand at Huffman's algorithm + + + align:start position:0% +now try your hand at Huffman's algorithm +to construct optimal variable length + + align:start position:0% +to construct optimal variable length + + + align:start position:0% +to construct optimal variable length +encoding x' \ No newline at end of file diff --git a/fAeShezAGLE.txt b/fAeShezAGLE.txt new file mode 100644 index 0000000000000000000000000000000000000000..2329418976e42ade44725cabd99b6f91bfcf6690 --- /dev/null +++ b/fAeShezAGLE.txt @@ -0,0 +1,11767 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer high quality educational + + align:start position:0% +to offer high quality educational + + + align:start position:0% +to offer high quality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +view additional materials from hundreds + + align:start position:0% +view additional materials from hundreds + + + align:start position:0% +view additional materials from hundreds +of MIT courses visit MIT open courseware + + align:start position:0% +of MIT courses visit MIT open courseware + + + align:start position:0% +of MIT courses visit MIT open courseware +at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu today we're going to start + + align:start position:0% +ocw.mit.edu today we're going to start + + + align:start position:0% +ocw.mit.edu today we're going to start +with a simple problem that many of you + + align:start position:0% +with a simple problem that many of you + + + align:start position:0% +with a simple problem that many of you +may have already encountered for example + + align:start position:0% +may have already encountered for example + + + align:start position:0% +may have already encountered for example +when you got a student loan or or if + + align:start position:0% +when you got a student loan or or if + + + align:start position:0% +when you got a student loan or or if +your family took a loan out on your + + align:start position:0% +your family took a loan out on your + + + align:start position:0% +your family took a loan out on your +house you know a home mortgage loan and + + align:start position:0% +house you know a home mortgage loan and + + + align:start position:0% +house you know a home mortgage loan and +it's the problem of pricing an annuity + + align:start position:0% +it's the problem of pricing an annuity + + + align:start position:0% +it's the problem of pricing an annuity +an annuity is a financial instrument + + align:start position:0% +an annuity is a financial instrument + + + align:start position:0% +an annuity is a financial instrument +that pays a fixed amount of money every + + align:start position:0% +that pays a fixed amount of money every + + + align:start position:0% +that pays a fixed amount of money every +year for some number of years and it has + + align:start position:0% +year for some number of years and it has + + + align:start position:0% +year for some number of years and it has +a value associated with it for example + + align:start position:0% +a value associated with it for example + + + align:start position:0% +a value associated with it for example +with the student loan the value is the + + align:start position:0% +with the student loan the value is the + + + align:start position:0% +with the student loan the value is the +amount of money they gave you to pay MIT + + align:start position:0% +amount of money they gave you to pay MIT + + + align:start position:0% +amount of money they gave you to pay MIT +then later in life every year or every + + align:start position:0% +then later in life every year or every + + + align:start position:0% +then later in life every year or every +month you're going to send them a check + + align:start position:0% +month you're going to send them a check + + + align:start position:0% +month you're going to send them a check +all right and you want to sort of equate + + align:start position:0% +all right and you want to sort of equate + + + align:start position:0% +all right and you want to sort of equate +those two things to find out you know + + align:start position:0% +those two things to find out you know + + + align:start position:0% +those two things to find out you know +are you getting enough money for the + + align:start position:0% +are you getting enough money for the + + + align:start position:0% +are you getting enough money for the +money you're going to pay back monthly + + align:start position:0% +money you're going to pay back monthly + + + align:start position:0% +money you're going to pay back monthly +sometime in the future so let's define + + align:start position:0% +sometime in the future so let's define + + + align:start position:0% +sometime in the future so let's define +this and there's a lot of variations on + + align:start position:0% +this and there's a lot of variations on + + + align:start position:0% +this and there's a lot of variations on +annuities but we'll start with one + + align:start position:0% +annuities but we'll start with one + + + align:start position:0% +annuities but we'll start with one +that's called an + + align:start position:0% + + + + align:start position:0% + +Nye + + align:start position:0% +Nye + + + align:start position:0% +Nye +M + + align:start position:0% +M + + + align:start position:0% +M +payment annuity + + align:start position:0% + + + + align:start position:0% + +and it works by + + align:start position:0% +and it works by + + + align:start position:0% +and it works by +paying + + align:start position:0% +paying + + + align:start position:0% +paying +M at the start of each + + align:start position:0% + + + + align:start position:0% + +year and it lasts for n + + align:start position:0% + + + + align:start position:0% + +years now usually n is finite but not + + align:start position:0% +years now usually n is finite but not + + + align:start position:0% +years now usually n is finite but not +always and in a few minutes we'll talk + + align:start position:0% +always and in a few minutes we'll talk + + + align:start position:0% +always and in a few minutes we'll talk +about the case when it's + + align:start position:0% +about the case when it's + + + align:start position:0% +about the case when it's +infinite uh but this includes you know + + align:start position:0% +infinite uh but this includes you know + + + align:start position:0% +infinite uh but this includes you know +home mortgages where you pay every month + + align:start position:0% +home mortgages where you pay every month + + + align:start position:0% +home mortgages where you pay every month +for 30 years meab bucks the lottery they + + align:start position:0% +for 30 years meab bucks the lottery they + + + align:start position:0% +for 30 years meab bucks the lottery they +don't actually give you the million + + align:start position:0% +don't actually give you the million + + + align:start position:0% +don't actually give you the million +dollars they give you $50,000 per year + + align:start position:0% +dollars they give you $50,000 per year + + + align:start position:0% +dollars they give you $50,000 per year +for 20 years and call it a million bucks + + align:start position:0% +for 20 years and call it a million bucks + + + align:start position:0% +for 20 years and call it a million bucks +retirement plans you know you pay in + + align:start position:0% +retirement plans you know you pay in + + + align:start position:0% +retirement plans you know you pay in +every year and then you get some big + + align:start position:0% +every year and then you get some big + + + align:start position:0% +every year and then you get some big +lump suum later life insurance benefits + + align:start position:0% +lump suum later life insurance benefits + + + align:start position:0% +lump suum later life insurance benefits +you know and so forth now if you go to + + align:start position:0% +you know and so forth now if you go to + + + align:start position:0% +you know and so forth now if you go to +Wall Street this is a big deal a lot of + + align:start position:0% +Wall Street this is a big deal a lot of + + + align:start position:0% +Wall Street this is a big deal a lot of +the stuff that happens on Wall Street + + align:start position:0% +the stuff that happens on Wall Street + + + align:start position:0% +the stuff that happens on Wall Street +involves annuities in one form or + + align:start position:0% +involves annuities in one form or + + + align:start position:0% +involves annuities in one form or +another packaging them all up uh and in + + align:start position:0% +another packaging them all up uh and in + + + align:start position:0% +another packaging them all up uh and in +fact we we'll look at later when we do + + align:start position:0% +fact we we'll look at later when we do + + + align:start position:0% +fact we we'll look at later when we do +probability it was how these things were + + align:start position:0% +probability it was how these things were + + + align:start position:0% +probability it was how these things were +packaged and sold that led to the S + + align:start position:0% +packaged and sold that led to the S + + + align:start position:0% +packaged and sold that led to the S +subprime mortgage disaster and we'll see + + align:start position:0% +subprime mortgage disaster and we'll see + + + align:start position:0% +subprime mortgage disaster and we'll see +how some confusion over Independence + + align:start position:0% +how some confusion over Independence + + + align:start position:0% +how some confusion over Independence +when you look at random variables led to + + align:start position:0% +when you look at random variables led to + + + align:start position:0% +when you look at random variables led to +the global recession a real disaster of + + align:start position:0% +the global recession a real disaster of + + + align:start position:0% +the global recession a real disaster of +course some people who understood how + + align:start position:0% +course some people who understood how + + + align:start position:0% +course some people who understood how +all that worked made hundreds of + + align:start position:0% +all that worked made hundreds of + + + align:start position:0% +all that worked made hundreds of +billions of dollars at the same time so + + align:start position:0% +billions of dollars at the same time so + + + align:start position:0% +billions of dollars at the same time so +it was sort of a money went from one + + align:start position:0% +it was sort of a money went from one + + + align:start position:0% +it was sort of a money went from one +place to another so it's pretty + + align:start position:0% +place to another so it's pretty + + + align:start position:0% +place to another so it's pretty +important to understand how much this is + + align:start position:0% +important to understand how much this is + + + align:start position:0% +important to understand how much this is +worth what is this instrument a piece of + + align:start position:0% +worth what is this instrument a piece of + + + align:start position:0% +worth what is this instrument a piece of +paper that says it'll pay you MLL at the + + align:start position:0% +paper that says it'll pay you MLL at the + + + align:start position:0% +paper that says it'll pay you MLL at the +beginning of each year for n years what + + align:start position:0% +beginning of each year for n years what + + + align:start position:0% +beginning of each year for n years what +is that worth today for example say I + + align:start position:0% +is that worth today for example say I + + + align:start position:0% +is that worth today for example say I +gave you a choice the mega buuck Choice + + align:start position:0% +gave you a choice the mega buuck Choice + + + align:start position:0% +gave you a choice the mega buuck Choice +50,000 a year for 20 years or a million + + align:start position:0% +50,000 a year for 20 years or a million + + + align:start position:0% +50,000 a year for 20 years or a million +dollars today how many people would + + align:start position:0% +dollars today how many people would + + + align:start position:0% +dollars today how many people would +prefer the 50,000 a year for 20 + + align:start position:0% +prefer the 50,000 a year for 20 + + + align:start position:0% +prefer the 50,000 a year for 20 +years few of you how many would prefer + + align:start position:0% +years few of you how many would prefer + + + align:start position:0% +years few of you how many would prefer +the million bucks right up front + + align:start position:0% +the million bucks right up front + + + align:start position:0% +the million bucks right up front +ah yeah much better okay always better + + align:start position:0% +ah yeah much better okay always better + + + align:start position:0% +ah yeah much better okay always better +to have the cash in hand because there's + + align:start position:0% +to have the cash in hand because there's + + + align:start position:0% +to have the cash in hand because there's +things like inflation pretty low now um + + align:start position:0% +things like inflation pretty low now um + + + align:start position:0% +things like inflation pretty low now um +interest you know you can put the money + + align:start position:0% +interest you know you can put the money + + + align:start position:0% +interest you know you can put the money +in the bank or invest it and make some + + align:start position:0% +in the bank or invest it and make some + + + align:start position:0% +in the bank or invest it and make some +money + + align:start position:0% +money + + + align:start position:0% +money +hopefully um so the million dollars + + align:start position:0% +hopefully um so the million dollars + + + align:start position:0% +hopefully um so the million dollars +today is a lot better which is why the + + align:start position:0% +today is a lot better which is why the + + + align:start position:0% +today is a lot better which is why the +state pays you 20 50 Grand a year for 20 + + align:start position:0% +state pays you 20 50 Grand a year for 20 + + + align:start position:0% +state pays you 20 50 Grand a year for 20 +years it's better for them and they call + + align:start position:0% +years it's better for them and they call + + + align:start position:0% +years it's better for them and they call +it a million bucks so that was pretty + + align:start position:0% +it a million bucks so that was pretty + + + align:start position:0% +it a million bucks so that was pretty +clear but what if I gave you this + + align:start position:0% +clear but what if I gave you this + + + align:start position:0% +clear but what if I gave you this +option 700 Grand today + + align:start position:0% +option 700 Grand today + + + align:start position:0% +option 700 Grand today +or 50 Grand a year for 20 years how many + + align:start position:0% +or 50 Grand a year for 20 years how many + + + align:start position:0% +or 50 Grand a year for 20 years how many +people want the cash up front 700 Grand + + align:start position:0% +people want the cash up front 700 Grand + + + align:start position:0% +people want the cash up front 700 Grand +only a few how many people want 20 grand + + align:start position:0% +only a few how many people want 20 grand + + + align:start position:0% +only a few how many people want 20 grand +50 Grand a year for 20 + + align:start position:0% +50 Grand a year for 20 + + + align:start position:0% +50 Grand a year for 20 +years all right we're almost that's + + align:start position:0% +years all right we're almost that's + + + align:start position:0% +years all right we're almost that's +pretty close to halfway how about 500 + + align:start position:0% +pretty close to halfway how about 500 + + + align:start position:0% +pretty close to halfway how about 500 +Grand today versus 50 Grand a year for + + align:start position:0% +Grand today versus 50 Grand a year for + + + align:start position:0% +Grand today versus 50 Grand a year for +20 years how many want five half a + + align:start position:0% +20 years how many want five half a + + + align:start position:0% +20 years how many want five half a +million + + align:start position:0% +million + + + align:start position:0% +million +today a lot of people like the cash you + + align:start position:0% +today a lot of people like the cash you + + + align:start position:0% +today a lot of people like the cash you +know it's this kind of a time you have + + align:start position:0% +know it's this kind of a time you have + + + align:start position:0% +know it's this kind of a time you have +the recession it's a disaster on Wall + + align:start position:0% +the recession it's a disaster on Wall + + + align:start position:0% +the recession it's a disaster on Wall +Street you know on Wall Street they like + + align:start position:0% +Street you know on Wall Street they like + + + align:start position:0% +Street you know on Wall Street they like +the cash how many want instead of a half + + align:start position:0% +the cash how many want instead of a half + + + align:start position:0% +the cash how many want instead of a half +a million upfront 50 Grand a year for 20 + + align:start position:0% +a million upfront 50 Grand a year for 20 + + + align:start position:0% +a million upfront 50 Grand a year for 20 +years right now we're about halfway all + + align:start position:0% +years right now we're about halfway all + + + align:start position:0% +years right now we're about halfway all +right well that's that's pretty good so + + align:start position:0% +right well that's that's pretty good so + + + align:start position:0% +right well that's that's pretty good so +we're going to find out what you should + + align:start position:0% +we're going to find out what you should + + + align:start position:0% +we're going to find out what you should +pay or at least one way of of estimating + + align:start position:0% +pay or at least one way of of estimating + + + align:start position:0% +pay or at least one way of of estimating +that now to do that we got to figure out + + align:start position:0% +that now to do that we got to figure out + + + align:start position:0% +that now to do that we got to figure out +what $1 today is worth in a + + align:start position:0% +what $1 today is worth in a + + + align:start position:0% +what $1 today is worth in a +year okay and to do that we make an + + align:start position:0% +year okay and to do that we make an + + + align:start position:0% +year okay and to do that we make an +assumption + + align:start position:0% + + + + align:start position:0% + +and the assumption is that there's a + + align:start position:0% +and the assumption is that there's a + + + align:start position:0% +and the assumption is that there's a +fixed we'll call it an interest + + align:start position:0% +fixed we'll call it an interest + + + align:start position:0% +fixed we'll call it an interest +rate it's sort of the the devaluation of + + align:start position:0% +rate it's sort of the the devaluation of + + + align:start position:0% +rate it's sort of the the devaluation of +the money per + + align:start position:0% + + + + align:start position:0% + +year we're going to call it P later + + align:start position:0% +year we're going to call it P later + + + align:start position:0% +year we're going to call it P later +we'll plug in values for p but you could + + align:start position:0% +we'll plug in values for p but you could + + + align:start position:0% +we'll plug in values for p but you could +think of it is like 6% 1% you know it's + + align:start position:0% +think of it is like 6% 1% you know it's + + + align:start position:0% +think of it is like 6% 1% you know it's +the money if you put money in a bank + + align:start position:0% +the money if you put money in a bank + + + align:start position:0% +the money if you put money in a bank +they'll give you some percent back every + + align:start position:0% +they'll give you some percent back every + + + align:start position:0% +they'll give you some percent back every +year and of course the fact that + + align:start position:0% +year and of course the fact that + + + align:start position:0% +year and of course the fact that +different people have different ideas of + + align:start position:0% +different people have different ideas of + + + align:start position:0% +different people have different ideas of +what this would be allows people to make + + align:start position:0% +what this would be allows people to make + + + align:start position:0% +what this would be allows people to make +money on Wall Street as we'll see a + + align:start position:0% +money on Wall Street as we'll see a + + + align:start position:0% +money on Wall Street as we'll see a +slight difference in in P can make big + + align:start position:0% +slight difference in in P can make big + + + align:start position:0% +slight difference in in P can make big +differences in what the annuity is worth + + align:start position:0% +differences in what the annuity is worth + + + align:start position:0% +differences in what the annuity is worth +so for + + align:start position:0% +so for + + + align:start position:0% +so for +example $1 + + align:start position:0% + + + + align:start position:0% + +today is going to equal 1 plus + + align:start position:0% +today is going to equal 1 plus + + + align:start position:0% +today is going to equal 1 plus +p in one + + align:start position:0% + + + + align:start position:0% + +year similarly $1 today how much is that + + align:start position:0% +year similarly $1 today how much is that + + + align:start position:0% +year similarly $1 today how much is that +going to be worth in two years + + align:start position:0% + + + + align:start position:0% + +say that P stays fixed the same over all + + align:start position:0% + + + + align:start position:0% + +time 1+ p^ + + align:start position:0% +time 1+ p^ + + + align:start position:0% +time 1+ p^ +s because every year you multiply what + + align:start position:0% +s because every year you multiply what + + + align:start position:0% +s because every year you multiply what +you got by one plus P because that's the + + align:start position:0% +you got by one plus P because that's the + + + align:start position:0% +you got by one plus P because that's the +interest you're getting right we'll + + align:start position:0% +interest you're getting right we'll + + + align:start position:0% +interest you're getting right we'll +think of it in terms of interest in + + align:start position:0% +think of it in terms of interest in + + + align:start position:0% +think of it in terms of interest in +three years $1 today is worth 1+ P + + align:start position:0% +three years $1 today is worth 1+ P + + + align:start position:0% +three years $1 today is worth 1+ P +cubed in 3 years and so + + align:start position:0% +cubed in 3 years and so + + + align:start position:0% +cubed in 3 years and so +forth all right now what we really care + + align:start position:0% +forth all right now what we really care + + + align:start position:0% +forth all right now what we really care +about is what's a dollar or M dollar + + align:start position:0% +about is what's a dollar or M dollar + + + align:start position:0% +about is what's a dollar or M dollar +worth today if you're getting it next + + align:start position:0% +worth today if you're getting it next + + + align:start position:0% +worth today if you're getting it next +year so we need to sort of flip this and + + align:start position:0% +year so we need to sort of flip this and + + + align:start position:0% +year so we need to sort of flip this and +back the other + + align:start position:0% + + + + align:start position:0% + +way so what is + + align:start position:0% +way so what is + + + align:start position:0% +way so what is +$1 in a year worth + + align:start position:0% + + + + align:start position:0% + +today in terms of + + align:start position:0% +today in terms of + + + align:start position:0% +today in terms of +P so if I'm be paid a dollar in a year + + align:start position:0% +P so if I'm be paid a dollar in a year + + + align:start position:0% +P so if I'm be paid a dollar in a year +what would be the equivalent amount to + + align:start position:0% +what would be the equivalent amount to + + + align:start position:0% +what would be the equivalent amount to +be paid + + align:start position:0% + + + + align:start position:0% + +today one over 1 plus + + align:start position:0% +today one over 1 plus + + + align:start position:0% +today one over 1 plus +P because What's Happening Here is as + + align:start position:0% +P because What's Happening Here is as + + + align:start position:0% +P because What's Happening Here is as +you go forward in a year you just + + align:start position:0% +you go forward in a year you just + + + align:start position:0% +you go forward in a year you just +multiply by 1 plus P so one over 1 plus + + align:start position:0% +multiply by 1 plus P so one over 1 plus + + + align:start position:0% +multiply by 1 plus P so one over 1 plus +P turns into + + align:start position:0% +P turns into + + + align:start position:0% +P turns into +$1 in a year being paid in a + + align:start position:0% +$1 in a year being paid in a + + + align:start position:0% +$1 in a year being paid in a +year all right what is one in a year in + + align:start position:0% +year all right what is one in a year in + + + align:start position:0% +year all right what is one in a year in +two + + align:start position:0% +two + + + align:start position:0% +two +years worth + + align:start position:0% + + + + align:start position:0% + +today 1 over 1 + P + + align:start position:0% +today 1 over 1 + P + + + align:start position:0% +today 1 over 1 + P +Squared all right so a dollar in two + + align:start position:0% +Squared all right so a dollar in two + + + align:start position:0% +Squared all right so a dollar in two +years is worth this much + + align:start position:0% +years is worth this much + + + align:start position:0% +years is worth this much +today all right well now we can use this + + align:start position:0% +today all right well now we can use this + + + align:start position:0% +today all right well now we can use this +to go figure out the current value of + + align:start position:0% +to go figure out the current value of + + + align:start position:0% +to go figure out the current value of +that + + align:start position:0% +that + + + align:start position:0% +that +annuity we just figure out what every + + align:start position:0% +annuity we just figure out what every + + + align:start position:0% +annuity we just figure out what every +payment is worth today and then add it + + align:start position:0% +payment is worth today and then add it + + + align:start position:0% +payment is worth today and then add it +up + + align:start position:0% +up + + + align:start position:0% +up +so we'll put the payments over here and + + align:start position:0% +so we'll put the payments over here and + + + align:start position:0% +so we'll put the payments over here and +we'll compute the current value of every + + align:start position:0% +we'll compute the current value of every + + + align:start position:0% +we'll compute the current value of every +payment on this + + align:start position:0% + + + + align:start position:0% + +side so with the annuity the way we've + + align:start position:0% +side so with the annuity the way we've + + + align:start position:0% +side so with the annuity the way we've +set it up is it pays MLL at the start of + + align:start position:0% +set it up is it pays MLL at the start of + + + align:start position:0% +set it up is it pays MLL at the start of +every year so the first payment is + + align:start position:0% +every year so the first payment is + + + align:start position:0% +every year so the first payment is +now so the first of the end payments is + + align:start position:0% +now so the first of the end payments is + + + align:start position:0% +now so the first of the end payments is +now and since it's being paid now that's + + align:start position:0% +now and since it's being paid now that's + + + align:start position:0% +now and since it's being paid now that's +worth M there's no uh devaluation + + align:start position:0% +worth M there's no uh devaluation + + + align:start position:0% +worth M there's no uh devaluation +the next payment is + + align:start position:0% +the next payment is + + + align:start position:0% +the next payment is +m in one + + align:start position:0% +m in one + + + align:start position:0% +m in one +year and so that's going to be + + align:start position:0% +year and so that's going to be + + + align:start position:0% +year and so that's going to be +worth M over 1 plus P + + align:start position:0% +worth M over 1 plus P + + + align:start position:0% +worth M over 1 plus P +today and the next payment is m in 2 + + align:start position:0% +today and the next payment is m in 2 + + + align:start position:0% +today and the next payment is m in 2 +years that's worth M over 1+ + + align:start position:0% +years that's worth M over 1+ + + + align:start position:0% +years that's worth M over 1+ +p^2 and we keep on going until the last + + align:start position:0% +p^2 and we keep on going until the last + + + align:start position:0% +p^2 and we keep on going until the last +payment it's the nth payment so it's MLL + + align:start position:0% +payment it's the nth payment so it's MLL + + + align:start position:0% +payment it's the nth payment so it's MLL +in N minus one + + align:start position:0% + + + + align:start position:0% + +years and so that's going to be worth + + align:start position:0% +years and so that's going to be worth + + + align:start position:0% +years and so that's going to be worth +M over 1 + P to the N minus + + align:start position:0% + + + + align:start position:0% + +one all right so we can compute the + + align:start position:0% +one all right so we can compute the + + + align:start position:0% +one all right so we can compute the +current value of all those payments then + + align:start position:0% +current value of all those payments then + + + align:start position:0% +current value of all those payments then +the + + align:start position:0% +the + + + align:start position:0% +the +annuity is computed the value is + + align:start position:0% +annuity is computed the value is + + + align:start position:0% +annuity is computed the value is +computed just by adding these up of all + + align:start position:0% +computed just by adding these up of all + + + align:start position:0% +computed just by adding these up of all +the current values so the total current + + align:start position:0% + + + + align:start position:0% + +value is the + + align:start position:0% +value is the + + + align:start position:0% +value is the +sum i = 0 to + + align:start position:0% +sum i = 0 to + + + align:start position:0% +sum i = 0 to +n-1 of M over 1 + P to the + + align:start position:0% +n-1 of M over 1 + P to the + + + align:start position:0% +n-1 of M over 1 + P to the +I and that is the total current + + align:start position:0% + + + + align:start position:0% + +value that's what you should pay + + align:start position:0% + + + + align:start position:0% + +today for the + + align:start position:0% +today for the + + + align:start position:0% +today for the +annuity any questions + + align:start position:0% +annuity any questions + + + align:start position:0% +annuity any questions +what we did + + align:start position:0% +what we did + + + align:start position:0% +what we did +here all + + align:start position:0% +here all + + + align:start position:0% +here all +right well of course what we'd like is a + + align:start position:0% +right well of course what we'd like is a + + + align:start position:0% +right well of course what we'd like is a +closed form expression here something + + align:start position:0% +closed form expression here something + + + align:start position:0% +closed form expression here something +that's simple so we could actually get a + + align:start position:0% +that's simple so we could actually get a + + + align:start position:0% +that's simple so we could actually get a +feel without having to add up all those + + align:start position:0% +feel without having to add up all those + + + align:start position:0% +feel without having to add up all those +terms uh and that's not hard to get in + + align:start position:0% +terms uh and that's not hard to get in + + + align:start position:0% +terms uh and that's not hard to get in +fact let's put this sum in a form that + + align:start position:0% +fact let's put this sum in a form that + + + align:start position:0% +fact let's put this sum in a form that +might be more + + align:start position:0% +might be more + + + align:start position:0% +might be more +familiar this equals we'll pull the M + + align:start position:0% +familiar this equals we'll pull the M + + + align:start position:0% +familiar this equals we'll pull the M +out in front and let's use x to be one + + align:start position:0% +out in front and let's use x to be one + + + align:start position:0% +out in front and let's use x to be one +over 1 plus P to the + + align:start position:0% + + + + align:start position:0% + +I and so + + align:start position:0% +I and so + + + align:start position:0% +I and so +x equal 1 over 1+ + + align:start position:0% + + + + align:start position:0% + +P all right and I wrote it this way + + align:start position:0% +P all right and I wrote it this way + + + align:start position:0% +P all right and I wrote it this way +because this might be familiar so + + align:start position:0% +because this might be familiar so + + + align:start position:0% +because this might be familiar so +everybody remember that from I think it + + align:start position:0% +everybody remember that from I think it + + + align:start position:0% +everybody remember that from I think it +was the second + + align:start position:0% + + + + align:start position:0% + +recitation anybody remember the formula + + align:start position:0% +recitation anybody remember the formula + + + align:start position:0% +recitation anybody remember the formula +what this evaluates + + align:start position:0% +what this evaluates + + + align:start position:0% +what this evaluates +to the sum of x to the I where I goes + + align:start position:0% +to the sum of x to the I where I goes + + + align:start position:0% +to the sum of x to the I where I goes +from 0 to n + + align:start position:0% +from 0 to n + + + align:start position:0% +from 0 to n +minus1 remember that we 1 - x to the + + align:start position:0% + + + + align:start position:0% + +n 1 - x all right in the second + + align:start position:0% +n 1 - x all right in the second + + + align:start position:0% +n 1 - x all right in the second +recitation I think we proved that this + + align:start position:0% +recitation I think we proved that this + + + align:start position:0% +recitation I think we proved that this +equals that what was the proof Technique + + align:start position:0% +equals that what was the proof Technique + + + align:start position:0% +equals that what was the proof Technique +we + + align:start position:0% +we + + + align:start position:0% +we +used induction okay all right + + align:start position:0% +used induction okay all right + + + align:start position:0% +used induction okay all right +so + + align:start position:0% +so + + + align:start position:0% +so +um all right so in + + align:start position:0% +um all right so in + + + align:start position:0% +um all right so in +fact there's a theorem + + align:start position:0% + + + + align:start position:0% + +here for all n bigger than equal to one + + align:start position:0% +here for all n bigger than equal to one + + + align:start position:0% +here for all n bigger than equal to one +and X not equal to + + align:start position:0% +and X not equal to + + + align:start position:0% +and X not equal to +one we proved I the sum IAL 0 to n + + align:start position:0% +one we proved I the sum IAL 0 to n + + + align:start position:0% +one we proved I the sum IAL 0 to n +minus1 x to the I = 1 - x the N over 1 - + + align:start position:0% +minus1 x to the I = 1 - x the N over 1 - + + + align:start position:0% +minus1 x to the I = 1 - x the N over 1 - +x okay and so this is a nice closed form + + align:start position:0% +x okay and so this is a nice closed form + + + align:start position:0% +x okay and so this is a nice closed form +no SU anymore just just that which is + + align:start position:0% +no SU anymore just just that which is + + + align:start position:0% +no SU anymore just just that which is +nice now induction proved it was the + + align:start position:0% +nice now induction proved it was the + + + align:start position:0% +nice now induction proved it was the +right + + align:start position:0% +right + + + align:start position:0% +right +answer once you once you knew knew it + + align:start position:0% +answer once you once you knew knew it + + + align:start position:0% +answer once you once you knew knew it +you know we gave it to you using + + align:start position:0% +you know we gave it to you using + + + align:start position:0% +you know we gave it to you using +induction to prove that theorem wasn't + + align:start position:0% +induction to prove that theorem wasn't + + + align:start position:0% +induction to prove that theorem wasn't +hard what we're going to look at doing + + align:start position:0% +hard what we're going to look at doing + + + align:start position:0% +hard what we're going to look at doing +this week and next week is figuring out + + align:start position:0% +this week and next week is figuring out + + + align:start position:0% +this week and next week is figuring out +how to figure out this was the answer in + + align:start position:0% +how to figure out this was the answer in + + + align:start position:0% +how to figure out this was the answer in +the first place methods for doing that + + align:start position:0% +the first place methods for doing that + + + align:start position:0% +the first place methods for doing that +to evaluate the + + align:start position:0% +to evaluate the + + + align:start position:0% +to evaluate the +sum and there's a lot of ways that you + + align:start position:0% +sum and there's a lot of ways that you + + + align:start position:0% +sum and there's a lot of ways that you +can do uh that particular sum probably + + align:start position:0% +can do uh that particular sum probably + + + align:start position:0% +can do uh that particular sum probably +the + + align:start position:0% +the + + + align:start position:0% +the +easiest is known as the perturbation + + align:start position:0% + + + + align:start position:0% + +method and this sometimes works with + + align:start position:0% +method and this sometimes works with + + + align:start position:0% +method and this sometimes works with +certainly with sums like that it often + + align:start position:0% +certainly with sums like that it often + + + align:start position:0% +certainly with sums like that it often +works the idea is as follows we're + + align:start position:0% +works the idea is as follows we're + + + align:start position:0% +works the idea is as follows we're +trying to compute the sum s which is 1 + + + align:start position:0% +trying to compute the sum s which is 1 + + + + align:start position:0% +trying to compute the sum s which is 1 + +x + + + align:start position:0% +x + + + + align:start position:0% +x + +x^2 plus X the n + + align:start position:0% +x^2 plus X the n + + + align:start position:0% +x^2 plus X the n +minus1 and what we're going to do is + + align:start position:0% +minus1 and what we're going to do is + + + align:start position:0% +minus1 and what we're going to do is +perturb it a little + + align:start position:0% +perturb it a little + + + align:start position:0% +perturb it a little +bit and then subtract to get big + + align:start position:0% +bit and then subtract to get big + + + align:start position:0% +bit and then subtract to get big +cancellation in this case it's pretty + + align:start position:0% +cancellation in this case it's pretty + + + align:start position:0% +cancellation in this case it's pretty +simple we multiply the sum by X to get x + + align:start position:0% +simple we multiply the sum by X to get x + + + align:start position:0% +simple we multiply the sum by X to get x ++ x^2 + + align:start position:0% + + + + align:start position:0% + ++ all right I've defined s to be that x + + align:start position:0% ++ all right I've defined s to be that x + + + align:start position:0% ++ all right I've defined s to be that x +x s well I get X Plus X2 and so forth up + + align:start position:0% +x s well I get X Plus X2 and so forth up + + + align:start position:0% +x s well I get X Plus X2 and so forth up +to x to the + + align:start position:0% +to x to the + + + align:start position:0% +to x to the +n and now I can subtract one from the + + align:start position:0% +n and now I can subtract one from the + + + align:start position:0% +n and now I can subtract one from the +other and almost everything + + align:start position:0% + + + + align:start position:0% + +cancels so I get one - x * s + + align:start position:0% +cancels so I get one - x * s + + + align:start position:0% +cancels so I get one - x * s +equals 1 these cancel cancel + + align:start position:0% +equals 1 these cancel cancel + + + align:start position:0% +equals 1 these cancel cancel +cancel - x + + align:start position:0% +cancel - x + + + align:start position:0% +cancel - x +n and + + align:start position:0% +n and + + + align:start position:0% +n and +therefore s = 1 - x n over 1 - + + align:start position:0% +therefore s = 1 - x n over 1 - + + + align:start position:0% +therefore s = 1 - x n over 1 - +x all right so that's sort of a + + align:start position:0% +x all right so that's sort of a + + + align:start position:0% +x all right so that's sort of a +a vague method um this gets used all the + + align:start position:0% +a vague method um this gets used all the + + + align:start position:0% +a vague method um this gets used all the +time in Applied Mathematics and they + + align:start position:0% +time in Applied Mathematics and they + + + align:start position:0% +time in Applied Mathematics and they +call it the perturbation method take + + align:start position:0% +call it the perturbation method take + + + align:start position:0% +call it the perturbation method take +your sum you know wiggle it around a + + align:start position:0% +your sum you know wiggle it around a + + + align:start position:0% +your sum you know wiggle it around a +little bit get something that looks + + align:start position:0% +little bit get something that looks + + + align:start position:0% +little bit get something that looks +close subtract it everything cancels + + align:start position:0% +close subtract it everything cancels + + + align:start position:0% +close subtract it everything cancels +life is nice and all of a sudden you + + align:start position:0% +life is nice and all of a sudden you + + + align:start position:0% +life is nice and all of a sudden you +figured out the + + align:start position:0% + + + + align:start position:0% + +answer okay so getting back to our + + align:start position:0% +answer okay so getting back to our + + + align:start position:0% +answer okay so getting back to our +annuity + + align:start position:0% +annuity + + + align:start position:0% +annuity +problem we can plug that formula + + align:start position:0% +problem we can plug that formula + + + align:start position:0% +problem we can plug that formula +back in here so the value of the + + align:start position:0% +back in here so the value of the + + + align:start position:0% +back in here so the value of the +annuity is M times 1 - x n over 1 - x + + align:start position:0% +annuity is M times 1 - x n over 1 - x + + + align:start position:0% +annuity is M times 1 - x n over 1 - x +we'll plug in x + + align:start position:0% +we'll plug in x + + + align:start position:0% +we'll plug in x += 1 over 1 + + + align:start position:0% += 1 over 1 + + + + align:start position:0% += 1 over 1 + +p and we get m 1 - 1 over 1 + + + align:start position:0% +p and we get m 1 - 1 over 1 + + + + align:start position:0% +p and we get m 1 - 1 over 1 + +P to the N over 1 - 1 over 1 + p + + align:start position:0% +P to the N over 1 - 1 over 1 + p + + + align:start position:0% +P to the N over 1 - 1 over 1 + p +just plugging in and now to simplify + + align:start position:0% +just plugging in and now to simplify + + + align:start position:0% +just plugging in and now to simplify +this I'll multiply the top and bottom by + + align:start position:0% +this I'll multiply the top and bottom by + + + align:start position:0% +this I'll multiply the top and bottom by +1 plus + + align:start position:0% + + + + align:start position:0% + +p and I'll get 1 plus P minus one on the + + align:start position:0% +p and I'll get 1 plus P minus one on the + + + align:start position:0% +p and I'll get 1 plus P minus one on the +bottom just gives me a p on the bottom + + align:start position:0% +bottom just gives me a p on the bottom + + + align:start position:0% +bottom just gives me a p on the bottom +have a 1 plus p on the top + + align:start position:0% +have a 1 plus p on the top + + + align:start position:0% +have a 1 plus p on the top +minus 1 over 1 + + + align:start position:0% +minus 1 over 1 + + + + align:start position:0% +minus 1 over 1 + +P to the N minus one all over + + align:start position:0% + + + + align:start position:0% + +P all right so now we have a formula + + align:start position:0% +P all right so now we have a formula + + + align:start position:0% +P all right so now we have a formula +closed form expression formula for the + + align:start position:0% +closed form expression formula for the + + + align:start position:0% +closed form expression formula for the +value of the annuity all you got to plug + + align:start position:0% +value of the annuity all you got to plug + + + align:start position:0% +value of the annuity all you got to plug +in is M the payment every year and the + + align:start position:0% +in is M the payment every year and the + + + align:start position:0% +in is M the payment every year and the +number of years and then P the interest + + align:start position:0% +number of years and then P the interest + + + align:start position:0% +number of years and then P the interest +rate and so for + + align:start position:0% + + + + align:start position:0% + +example if we made M be + + align:start position:0% + + + + align:start position:0% + +$50,000 as in the lottery we made n be + + align:start position:0% +$50,000 as in the lottery we made n be + + + align:start position:0% +$50,000 as in the lottery we made n be + + align:start position:0% + + + align:start position:0% +years and say we took 6% interest which + + align:start position:0% +years and say we took 6% interest which + + + align:start position:0% +years and say we took 6% interest which +is actually very good these + + align:start position:0% +is actually very good these + + + align:start position:0% +is actually very good these +days and I plug those in here the value + + align:start position:0% +days and I plug those in here the value + + + align:start position:0% +days and I plug those in here the value +is going to be + + align:start position:0% +is going to be + + + align:start position:0% +is going to be +$67,900 + + align:start position:0% + + + + align:start position:0% + +all right so those of you that preferred + + align:start position:0% +all right so those of you that preferred + + + align:start position:0% +all right so those of you that preferred +700 Grand if you assume 6% interest + + align:start position:0% +700 Grand if you assume 6% interest + + + align:start position:0% +700 Grand if you assume 6% interest +you're right those of you preferred 500 + + align:start position:0% +you're right those of you preferred 500 + + + align:start position:0% +you're right those of you preferred 500 +Grand no you're better off waiting and + + align:start position:0% +Grand no you're better off waiting and + + + align:start position:0% +Grand no you're better off waiting and +getting your 50 Grand a year now of + + align:start position:0% +getting your 50 Grand a year now of + + + align:start position:0% +getting your 50 Grand a year now of +course if the interest rate is lower + + align:start position:0% +course if the interest rate is lower + + + align:start position:0% +course if the interest rate is lower +well that changes things all right that + + align:start position:0% +well that changes things all right that + + + align:start position:0% +well that changes things all right that +shifts it even more the annuity is worth + + align:start position:0% +shifts it even more the annuity is worth + + + align:start position:0% +shifts it even more the annuity is worth +even more if the interest rate is lower + + align:start position:0% +even more if the interest rate is lower + + + align:start position:0% +even more if the interest rate is lower +right if p is + + align:start position:0% +right if p is + + + align:start position:0% +right if p is +smaller in fact say p was + + align:start position:0% +smaller in fact say p was + + + align:start position:0% +smaller in fact say p was +zero say the interest rate is zero so a + + align:start position:0% +zero say the interest rate is zero so a + + + align:start position:0% +zero say the interest rate is zero so a +dollar today equals a dollar tomorrow + + align:start position:0% +dollar today equals a dollar tomorrow + + + align:start position:0% +dollar today equals a dollar tomorrow +then what is the lottery + + align:start position:0% +then what is the lottery + + + align:start position:0% +then what is the lottery +worth a million dollars all right and + + align:start position:0% +worth a million dollars all right and + + + align:start position:0% +worth a million dollars all right and +the bigger P gets the less your payment + + align:start position:0% +the bigger P gets the less your payment + + + align:start position:0% +the bigger P gets the less your payment +is + + align:start position:0% + + + + align:start position:0% + +worth all right any questions about that + + align:start position:0% + + + + align:start position:0% + +okay what if you were paid + + align:start position:0% +okay what if you were paid + + + align:start position:0% +okay what if you were paid +$50,000 a year + + align:start position:0% +$50,000 a year + + + align:start position:0% +$50,000 a year +forever you live forever or it goes to + + align:start position:0% +forever you live forever or it goes to + + + align:start position:0% +forever you live forever or it goes to +your estate and your airs $50,000 a year + + align:start position:0% +your estate and your airs $50,000 a year + + + align:start position:0% +your estate and your airs $50,000 a year +forever or a million dollars + + align:start position:0% + + + + align:start position:0% + +today how many people want the millionar + + align:start position:0% +today how many people want the millionar + + + align:start position:0% +today how many people want the millionar +today how many want 50 Grand a year + + align:start position:0% +today how many want 50 Grand a year + + + align:start position:0% +today how many want 50 Grand a year +forever + + align:start position:0% +forever + + + align:start position:0% +forever +sounds good you know 50 that's an + + align:start position:0% +sounds good you know 50 that's an + + + align:start position:0% +sounds good you know 50 that's an +infinite amount of money sort + + align:start position:0% +infinite amount of money sort + + + align:start position:0% +infinite amount of money sort +of it's not as good as it sounds let's + + align:start position:0% +of it's not as good as it sounds let's + + + align:start position:0% +of it's not as good as it sounds let's +let's see why uh so this is a case where + + align:start position:0% +let's see why uh so this is a case where + + + align:start position:0% +let's see why uh so this is a case where +n equals + + align:start position:0% + + + + align:start position:0% + +infinity and so I'll claim that if n + + align:start position:0% +infinity and so I'll claim that if n + + + align:start position:0% +infinity and so I'll claim that if n +equals + + align:start position:0% +equals + + + align:start position:0% +equals +infinity then the value of this + + align:start position:0% +infinity then the value of this + + + align:start position:0% +infinity then the value of this +annuity is just m * 1 + p over p + + align:start position:0% + + + + align:start position:0% + +let's see why that's the + + align:start position:0% +let's see why that's the + + + align:start position:0% +let's see why that's the +case you know it sounds hard to evaluate + + align:start position:0% +case you know it sounds hard to evaluate + + + align:start position:0% +case you know it sounds hard to evaluate +because it's an infinite number of + + align:start position:0% +because it's an infinite number of + + + align:start position:0% +because it's an infinite number of +payments but what happens here when n + + align:start position:0% +payments but what happens here when n + + + align:start position:0% +payments but what happens here when n +goes to + + align:start position:0% +goes to + + + align:start position:0% +goes to +Infinity what happens to this + + align:start position:0% +Infinity what happens to this + + + align:start position:0% +Infinity what happens to this +thing that goes to zero as n goes to + + align:start position:0% +thing that goes to zero as n goes to + + + align:start position:0% +thing that goes to zero as n goes to +Infinity as long as p is bigger than + + align:start position:0% +Infinity as long as p is bigger than + + + align:start position:0% +Infinity as long as p is bigger than +zero so we're going to assume 6% + + align:start position:0% +zero so we're going to assume 6% + + + align:start position:0% +zero so we're going to assume 6% +interest so that goes away so the + + align:start position:0% +interest so that goes away so the + + + align:start position:0% +interest so that goes away so the +annuity is worth just that M * 1 plus p + + align:start position:0% +annuity is worth just that M * 1 plus p + + + align:start position:0% +annuity is worth just that M * 1 plus p +over p + + align:start position:0% +over p + + + align:start position:0% +over p +because the LI the limit as n goes to + + align:start position:0% +because the LI the limit as n goes to + + + align:start position:0% +because the LI the limit as n goes to +Infinity of 1 over 1 + P to the N minus + + align:start position:0% +Infinity of 1 over 1 + P to the N minus + + + align:start position:0% +Infinity of 1 over 1 + P to the N minus +one that's going to + + align:start position:0% +one that's going to + + + align:start position:0% +one that's going to +zero so the + + align:start position:0% +zero so the + + + align:start position:0% +zero so the +value for m is + + align:start position:0% + + + + align:start position:0% + +$50,000 and at + + align:start position:0% + + + + align:start position:0% + +6% V is only $883,000 + + align:start position:0% + + + + align:start position:0% + +all right so you're better off taking a + + align:start position:0% +all right so you're better off taking a + + + align:start position:0% +all right so you're better off taking a +million dollars today than $50,000 a + + align:start position:0% +million dollars today than $50,000 a + + + align:start position:0% +million dollars today than $50,000 a +year + + align:start position:0% +year + + + align:start position:0% +year +forever now if you think about it you + + align:start position:0% +forever now if you think about it you + + + align:start position:0% +forever now if you think about it you +think about it as an interest rate why + + align:start position:0% +think about it as an interest rate why + + + align:start position:0% +think about it as an interest rate why +should it be obvious that you're better + + align:start position:0% +should it be obvious that you're better + + + align:start position:0% +should it be obvious that you're better +off with a million dollars today than 50 + + align:start position:0% +off with a million dollars today than 50 + + + align:start position:0% +off with a million dollars today than 50 +Grand a year + + align:start position:0% +Grand a year + + + align:start position:0% +Grand a year +forever think about what you could do + + align:start position:0% +forever think about what you could do + + + align:start position:0% +forever think about what you could do +with that million dollars if you had it + + align:start position:0% +with that million dollars if you had it + + + align:start position:0% +with that million dollars if you had it +today at 6% + + align:start position:0% +today at 6% + + + align:start position:0% +today at 6% +interest what would you do with it to to + + align:start position:0% +interest what would you do with it to to + + + align:start position:0% +interest what would you do with it to to +make more money than 50 Grand a year + + align:start position:0% +make more money than 50 Grand a year + + + align:start position:0% +make more money than 50 Grand a year +forever + + align:start position:0% + + + + align:start position:0% + +yeah yeah in this model if the interest + + align:start position:0% +yeah yeah in this model if the interest + + + align:start position:0% +yeah yeah in this model if the interest +rate is 6% you can put in the bank make + + align:start position:0% +rate is 6% you can put in the bank make + + + align:start position:0% +rate is 6% you can put in the bank make +6% every year that's 60 Grand a year + + align:start position:0% +6% every year that's 60 Grand a year + + + align:start position:0% +6% every year that's 60 Grand a year +forever better than 50 Grand a year + + align:start position:0% +forever better than 50 Grand a year + + + align:start position:0% +forever better than 50 Grand a year +forever all right so maybe it's you know + + align:start position:0% +forever all right so maybe it's you know + + + align:start position:0% +forever all right so maybe it's you know +even without doing the math you can tell + + align:start position:0% +even without doing the math you can tell + + + align:start position:0% +even without doing the math you can tell +which way it's going to go but this + + align:start position:0% +which way it's going to go but this + + + align:start position:0% +which way it's going to go but this +tells you exactly what it's + + align:start position:0% +tells you exactly what it's + + + align:start position:0% +tells you exactly what it's +worth all right any + + align:start position:0% + + + + align:start position:0% + +questions + + align:start position:0% +questions + + + align:start position:0% +questions +okay + + align:start position:0% +okay + + + align:start position:0% +okay +yeah how much worth to you right now + + align:start position:0% +yeah how much worth to you right now + + + align:start position:0% +yeah how much worth to you right now +yeah so um it might be like if you have + + align:start position:0% +yeah so um it might be like if you have + + + align:start position:0% +yeah so um it might be like if you have +$1 in the future + + align:start position:0% +$1 in the future + + + align:start position:0% +$1 in the future +yeah + + align:start position:0% + + + + align:start position:0% + +right lat + + align:start position:0% +right lat + + + align:start position:0% +right lat +it's ah so if you move yourself forward + + align:start position:0% +it's ah so if you move yourself forward + + + align:start position:0% +it's ah so if you move yourself forward +in time $1 in a year in a year will be + + align:start position:0% +in time $1 in a year in a year will be + + + align:start position:0% +in time $1 in a year in a year will be +worth $1 to you + + align:start position:0% +worth $1 to you + + + align:start position:0% +worth $1 to you +but today it's worth less than a dollar + + align:start position:0% +but today it's worth less than a dollar + + + align:start position:0% +but today it's worth less than a dollar +to you because you could take the dollar + + align:start position:0% +to you because you could take the dollar + + + align:start position:0% +to you because you could take the dollar +today and invest it in the bank and it's + + align:start position:0% +today and invest it in the bank and it's + + + align:start position:0% +today and invest it in the bank and it's +worth more in a year because the money + + align:start position:0% +worth more in a year because the money + + + align:start position:0% +worth more in a year because the money +grows in value is a way to think of it + + align:start position:0% +grows in value is a way to think of it + + + align:start position:0% +grows in value is a way to think of it +because you can earn interest on it + + align:start position:0% +because you can earn interest on it + + + align:start position:0% +because you can earn interest on it +what's + + align:start position:0% +what's + + + align:start position:0% +what's +that yeah if depend yeah if you just + + align:start position:0% +that yeah if depend yeah if you just + + + align:start position:0% +that yeah if depend yeah if you just +spend it well then you at least you had + + align:start position:0% +spend it well then you at least you had + + + align:start position:0% +spend it well then you at least you had +the use of what you spend it on for the + + align:start position:0% +the use of what you spend it on for the + + + align:start position:0% +the use of what you spend it on for the +year so there's some other kind of value + + align:start position:0% +year so there's some other kind of value + + + align:start position:0% +year so there's some other kind of value +right maybe you bought a house or you + + align:start position:0% +right maybe you bought a house or you + + + align:start position:0% +right maybe you bought a house or you +know something that maybe something that + + align:start position:0% +know something that maybe something that + + + align:start position:0% +know something that maybe something that +even appreciated in value + + align:start position:0% +even appreciated in value + + + align:start position:0% +even appreciated in value +okay but yeah these things get get you + + align:start position:0% +okay but yeah these things get get you + + + align:start position:0% +okay but yeah these things get get you +know sort of squishy and that is where a + + align:start position:0% +know sort of squishy and that is where a + + + align:start position:0% +know sort of squishy and that is where a +lot of people make make money on Wall + + align:start position:0% +lot of people make make money on Wall + + + align:start position:0% +lot of people make make money on Wall +Street is because different companies + + align:start position:0% +Street is because different companies + + + align:start position:0% +Street is because different companies +have different needs for money they have + + align:start position:0% +have different needs for money they have + + + align:start position:0% +have different needs for money they have +different views of what the interest + + align:start position:0% +different views of what the interest + + + align:start position:0% +different views of what the interest +rates are going to be and you can play + + align:start position:0% +rates are going to be and you can play + + + align:start position:0% +rates are going to be and you can play +in the middle all right make make a lot + + align:start position:0% +in the middle all right make make a lot + + + align:start position:0% +in the middle all right make make a lot +of money that + + align:start position:0% +of money that + + + align:start position:0% +of money that +way okay + + align:start position:0% + + + + align:start position:0% + +all right so more generally there's a + + align:start position:0% +all right so more generally there's a + + + align:start position:0% +all right so more generally there's a +corollary to the + + align:start position:0% +corollary to the + + + align:start position:0% +corollary to the +theorem and that is that if the absolute + + align:start position:0% +theorem and that is that if the absolute + + + align:start position:0% +theorem and that is that if the absolute +value of x is less than one then the + + align:start position:0% +value of x is less than one then the + + + align:start position:0% +value of x is less than one then the +sum IAL 0 To infinity x to the I is just + + align:start position:0% +sum IAL 0 To infinity x to the I is just + + + align:start position:0% +sum IAL 0 To infinity x to the I is just +1 over 1 - + + align:start position:0% +1 over 1 - + + + align:start position:0% +1 over 1 - +x all right and we didn't prove this + + align:start position:0% +x all right and we didn't prove this + + + align:start position:0% +x all right and we didn't prove this +back in the second recitation because + + align:start position:0% +back in the second recitation because + + + align:start position:0% +back in the second recitation because +there's no n to induct on here but the + + align:start position:0% +there's no n to induct on here but the + + + align:start position:0% +there's no n to induct on here but the +proof is simple from the + + align:start position:0% +proof is simple from the + + + align:start position:0% +proof is simple from the +theorem and it's simply because if x is + + align:start position:0% +theorem and it's simply because if x is + + + align:start position:0% +theorem and it's simply because if x is +less than one an absolute value as n + + align:start position:0% +less than one an absolute value as n + + + align:start position:0% +less than one an absolute value as n +goes to Infinity that goes to zero and + + align:start position:0% +goes to Infinity that goes to zero and + + + align:start position:0% +goes to Infinity that goes to zero and +so you're just left with one over one - + + align:start position:0% + + + + align:start position:0% + +x okay so for example + + align:start position:0% +x okay so for example + + + align:start position:0% +x okay so for example +uh what's this sum this one you all know + + align:start position:0% +uh what's this sum this one you all know + + + align:start position:0% +uh what's this sum this one you all know +I'm + + align:start position:0% + + + + align:start position:0% + +sure out to Infinity what's that sum + + align:start position:0% +sure out to Infinity what's that sum + + + align:start position:0% +sure out to Infinity what's that sum +to to two yeah it's 1 over 1 minus a + + align:start position:0% +to to two yeah it's 1 over 1 minus a + + + align:start position:0% +to to two yeah it's 1 over 1 minus a +half which is + + align:start position:0% +half which is + + + align:start position:0% +half which is +two what about this + + align:start position:0% + + + + align:start position:0% + +sum out to Infinity what does that sum + + align:start position:0% +sum out to Infinity what does that sum + + + align:start position:0% +sum out to Infinity what does that sum +to + + align:start position:0% + + + + align:start position:0% + +yeah three Hales 1 over 1 - A3 is + + align:start position:0% +yeah three Hales 1 over 1 - A3 is + + + align:start position:0% +yeah three Hales 1 over 1 - A3 is +three all right so easy + + align:start position:0% +three all right so easy + + + align:start position:0% +three all right so easy +cories uh these are all examples of + + align:start position:0% +cories uh these are all examples of + + + align:start position:0% +cories uh these are all examples of +geometric series that's what a + + align:start position:0% +geometric series that's what a + + + align:start position:0% +geometric series that's what a +definition of a geometric series is + + align:start position:0% +definition of a geometric series is + + + align:start position:0% +definition of a geometric series is +something is going down by a fixed each + + align:start position:0% +something is going down by a fixed each + + + align:start position:0% +something is going down by a fixed each +term goes down by the same fixed amount + + align:start position:0% +term goes down by the same fixed amount + + + align:start position:0% +term goes down by the same fixed amount +every time and geometric series + + align:start position:0% +every time and geometric series + + + align:start position:0% +every time and geometric series +generally sum to something that is very + + align:start position:0% +generally sum to something that is very + + + align:start position:0% +generally sum to something that is very +close to the largest term in this case + + align:start position:0% +close to the largest term in this case + + + align:start position:0% +close to the largest term in this case +it's one + + align:start position:0% +it's one + + + align:start position:0% +it's one +very common because of that formula it's + + align:start position:0% +very common because of that formula it's + + + align:start position:0% +very common because of that formula it's +one over one minus + + align:start position:0% + + + + align:start position:0% + +X any questions about this or geometric + + align:start position:0% + + + + align:start position:0% + +series all + + align:start position:0% +series all + + + align:start position:0% +series all +right well those are straight geometric + + align:start position:0% +right well those are straight geometric + + + align:start position:0% +right well those are straight geometric +sums sometimes you run into things that + + align:start position:0% +sums sometimes you run into things that + + + align:start position:0% +sums sometimes you run into things that +are a little bit more complicated for + + align:start position:0% +are a little bit more complicated for + + + align:start position:0% +are a little bit more complicated for +example say I have this kind of a sum I + + align:start position:0% +example say I have this kind of a sum I + + + align:start position:0% +example say I have this kind of a sum I += 1 to + + align:start position:0% += 1 to + + + align:start position:0% += 1 to +n i * x to the + + align:start position:0% +n i * x to the + + + align:start position:0% +n i * x to the +I other are adding up x + + + align:start position:0% +I other are adding up x + + + + align:start position:0% +I other are adding up x + +2x^2 + 3x + + align:start position:0% +2x^2 + 3x + + + align:start position:0% +2x^2 + 3x +cubed and so forth up to n x to the + + align:start position:0% +cubed and so forth up to n x to the + + + align:start position:0% +cubed and so forth up to n x to the +N you know that's a little more + + align:start position:0% +N you know that's a little more + + + align:start position:0% +N you know that's a little more +complicated the terms are + + align:start position:0% +complicated the terms are + + + align:start position:0% +complicated the terms are +getting you know decreasing by a factor + + align:start position:0% +getting you know decreasing by a factor + + + align:start position:0% +getting you know decreasing by a factor +of X increasing by one in terms of the + + align:start position:0% +of X increasing by one in terms of the + + + align:start position:0% +of X increasing by one in terms of the +coefficient every time little trickier + + align:start position:0% +coefficient every time little trickier + + + align:start position:0% +coefficient every time little trickier +so say we wanted to get a closed form + + align:start position:0% +so say we wanted to get a closed form + + + align:start position:0% +so say we wanted to get a closed form +expression for that there's several ways + + align:start position:0% +expression for that there's several ways + + + align:start position:0% +expression for that there's several ways +we can do it the first would be to try + + align:start position:0% +we can do it the first would be to try + + + align:start position:0% +we can do it the first would be to try +to use perturbation the perturbation + + align:start position:0% +to use perturbation the perturbation + + + align:start position:0% +to use perturbation the perturbation +method so let's try + + align:start position:0% +method so let's try + + + align:start position:0% +method so let's try +that so we write s = x + 2x^2 + 3x + + align:start position:0% +that so we write s = x + 2x^2 + 3x + + + align:start position:0% +that so we write s = x + 2x^2 + 3x +cubed plus n x the + + align:start position:0% +cubed plus n x the + + + align:start position:0% +cubed plus n x the +n and let's try the same perturbation + + align:start position:0% +n and let's try the same perturbation + + + align:start position:0% +n and let's try the same perturbation +multiply by + + align:start position:0% +multiply by + + + align:start position:0% +multiply by +X I get x2 + 2 x + + align:start position:0% +X I get x2 + 2 x + + + align:start position:0% +X I get x2 + 2 x +cubed + n -1 x n + n x the n + + + align:start position:0% +cubed + n -1 x n + n x the n + + + + align:start position:0% +cubed + n -1 x n + n x the n + +one and then I subtract to try to get + + align:start position:0% +one and then I subtract to try to get + + + align:start position:0% +one and then I subtract to try to get +all the + + align:start position:0% + + + + align:start position:0% + +cancellation so and I do that I get 1 - + + align:start position:0% +cancellation so and I do that I get 1 - + + + align:start position:0% +cancellation so and I do that I get 1 - +x * + + align:start position:0% +x * + + + align:start position:0% +x * +S I didn't quite cancel + + align:start position:0% +S I didn't quite cancel + + + align:start position:0% +S I didn't quite cancel +everything x + + + align:start position:0% +everything x + + + + align:start position:0% +everything x + +X2 + x + + align:start position:0% +X2 + x + + + align:start position:0% +X2 + x +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +cubed plus x to the N plus n or minus n + + align:start position:0% +cubed plus x to the N plus n or minus n + + + align:start position:0% +cubed plus x to the N plus n or minus n +x to the n + one ah it didn't quite + + align:start position:0% +x to the n + one ah it didn't quite + + + align:start position:0% +x to the n + one ah it didn't quite +work anybody see a way though I can fix + + align:start position:0% +work anybody see a way though I can fix + + + align:start position:0% +work anybody see a way though I can fix +this + + align:start position:0% + + + + align:start position:0% + +up what about this piece that's still a + + align:start position:0% +up what about this piece that's still a + + + align:start position:0% +up what about this piece that's still a +mess here can I simplify + + align:start position:0% +mess here can I simplify + + + align:start position:0% +mess here can I simplify +that yeah + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% +um + + + align:start position:0% +um +yeah there's a simpler way yeah that's a + + align:start position:0% +yeah there's a simpler way yeah that's a + + + align:start position:0% +yeah there's a simpler way yeah that's a +geometric series that's a geometric + + align:start position:0% +geometric series that's a geometric + + + align:start position:0% +geometric series that's a geometric +series we just got the formula for it so + + align:start position:0% +series we just got the formula for it so + + + align:start position:0% +series we just got the formula for it so +that's easy this + + align:start position:0% +that's easy this + + + align:start position:0% +that's easy this +equals 1 - x the N over 1 - x minus the + + align:start position:0% +equals 1 - x the N over 1 - x minus the + + + align:start position:0% +equals 1 - x the N over 1 - x minus the +one because I'm missing the one here so + + align:start position:0% +one because I'm missing the one here so + + + align:start position:0% +one because I'm missing the one here so +we can rewrite this whole thing over + + align:start position:0% + + + + align:start position:0% + +here oops yikes got + + align:start position:0% + + + + align:start position:0% + +attacked what's + + align:start position:0% + + + + align:start position:0% + +that + + align:start position:0% +that + + + align:start position:0% +that +yes it would that's right I got to add + + align:start position:0% +yes it would that's right I got to add + + + align:start position:0% +yes it would that's right I got to add +one to there + + align:start position:0% +one to there + + + align:start position:0% +one to there +there okay so that's good so that says + + align:start position:0% +there okay so that's good so that says + + + align:start position:0% +there okay so that's good so that says +that 1 - x * s = 1 - x n + 1 over 1 - x + + align:start position:0% +that 1 - x * s = 1 - x n + 1 over 1 - x + + + align:start position:0% +that 1 - x * s = 1 - x n + 1 over 1 - x +-1 and then I got to remember to + + align:start position:0% +-1 and then I got to remember to + + + align:start position:0% +-1 and then I got to remember to +subtract that term too minus n actually + + align:start position:0% +subtract that term too minus n actually + + + align:start position:0% +subtract that term too minus n actually +n + + + align:start position:0% +n + + + + align:start position:0% +n + +one that means now I just divide through + + align:start position:0% +one that means now I just divide through + + + align:start position:0% +one that means now I just divide through +and I simplify divide through by 1 - x + + align:start position:0% +and I simplify divide through by 1 - x + + + align:start position:0% +and I simplify divide through by 1 - x +and simplify and I get the following + + align:start position:0% +and simplify and I get the following + + + align:start position:0% +and simplify and I get the following +formula I won't go through all the + + align:start position:0% +formula I won't go through all the + + + align:start position:0% +formula I won't go through all the +details but it's not + + align:start position:0% + + + + align:start position:0% + +hard let's see if I got that right yeah + + align:start position:0% +hard let's see if I got that right yeah + + + align:start position:0% +hard let's see if I got that right yeah +that looks right okay so that is the + + align:start position:0% +that looks right okay so that is the + + + align:start position:0% +that looks right okay so that is the +closed form expression for that sum + + align:start position:0% +closed form expression for that sum + + + align:start position:0% +closed form expression for that sum +which we can get from the perturbation + + align:start position:0% +which we can get from the perturbation + + + align:start position:0% +which we can get from the perturbation +method and the fact that we'd already + + align:start position:0% +method and the fact that we'd already + + + align:start position:0% +method and the fact that we'd already +done the geometric + + align:start position:0% +done the geometric + + + align:start position:0% +done the geometric +series all right there's another way to + + align:start position:0% +series all right there's another way to + + + align:start position:0% +series all right there's another way to +compute these kinds of + + align:start position:0% +compute these kinds of + + + align:start position:0% +compute these kinds of +sums which I want to show you because + + align:start position:0% +sums which I want to show you because + + + align:start position:0% +sums which I want to show you because +can be + + align:start position:0% + + + + align:start position:0% + +useful so we're going to do the same sum + + align:start position:0% +useful so we're going to do the same sum + + + align:start position:0% +useful so we're going to do the same sum +and and derive the formula a different + + align:start position:0% +and and derive the formula a different + + + align:start position:0% +and and derive the formula a different +way this method is called the derivative + + align:start position:0% +way this method is called the derivative + + + align:start position:0% +way this method is called the derivative +method + + align:start position:0% + + + + align:start position:0% + +and the idea is to start with the + + align:start position:0% +and the idea is to start with the + + + align:start position:0% +and the idea is to start with the +geometric series which it's close to and + + align:start position:0% +geometric series which it's close to and + + + align:start position:0% +geometric series which it's close to and +then take a + + align:start position:0% +then take a + + + align:start position:0% +then take a +derivative so for X not equal to one we + + align:start position:0% +derivative so for X not equal to one we + + + align:start position:0% +derivative so for X not equal to one we +already know from the theorem that I = 0 + + align:start position:0% +already know from the theorem that I = 0 + + + align:start position:0% +already know from the theorem that I = 0 +to n x the I = 1 - x n + 1 over 1 - x + + align:start position:0% +to n x the I = 1 - x n + 1 over 1 - x + + + align:start position:0% +to n x the I = 1 - x n + 1 over 1 - x +that was the theorem we already know + + align:start position:0% +that was the theorem we already know + + + align:start position:0% +that was the theorem we already know +that now I can take the d derivative of + + align:start position:0% +that now I can take the d derivative of + + + align:start position:0% +that now I can take the d derivative of +both sides and let's see what we get by + + align:start position:0% +both sides and let's see what we get by + + + align:start position:0% +both sides and let's see what we get by +taking the + + align:start position:0% +taking the + + + align:start position:0% +taking the +derivative well + + align:start position:0% +derivative well + + + align:start position:0% +derivative well +here I get the sum the derivative of x + + align:start position:0% +here I get the sum the derivative of x + + + align:start position:0% +here I get the sum the derivative of x +to the I is just I * X the + + align:start position:0% +to the I is just I * X the + + + align:start position:0% +to the I is just I * X the +ius1 the derivative over here is a + + align:start position:0% +ius1 the derivative over here is a + + + align:start position:0% +ius1 the derivative over here is a +little + + align:start position:0% +little + + + align:start position:0% +little +Messier I got to have I take 1 - x times + + align:start position:0% +Messier I got to have I take 1 - x times + + + align:start position:0% +Messier I got to have I take 1 - x times +the derivative of + + align:start position:0% + + + + align:start position:0% + +that derivative of this is now minus n + + align:start position:0% +that derivative of this is now minus n + + + align:start position:0% +that derivative of this is now minus n +Plus + + align:start position:0% +Plus + + + align:start position:0% +Plus +1 x to the + + align:start position:0% +1 x to the + + + align:start position:0% +1 x to the +N then I take this times the derivative + + align:start position:0% +N then I take this times the derivative + + + align:start position:0% +N then I take this times the derivative +of + + align:start position:0% +of + + + align:start position:0% +of +that is now Min - + + align:start position:0% +that is now Min - + + + align:start position:0% +that is now Min - +-1 1 - x n + + + align:start position:0% +-1 1 - x n + + + + align:start position:0% +-1 1 - x n + +1 and then I divide + + align:start position:0% +1 and then I divide + + + align:start position:0% +1 and then I divide +by that + + align:start position:0% + + + + align:start position:0% + +squared now when we compute all that out + + align:start position:0% +squared now when we compute all that out + + + align:start position:0% +squared now when we compute all that out +we get + + align:start position:0% +we get + + + align:start position:0% +we get +this 1 minus n + 1 x the + + align:start position:0% +this 1 minus n + 1 x the + + + align:start position:0% +this 1 minus n + 1 x the +n + n x n + + + align:start position:0% +n + n x n + + + + align:start position:0% +n + n x n + +1 over 1 - + + align:start position:0% +1 over 1 - + + + align:start position:0% +1 over 1 - +x^2 right I won't drag you through the + + align:start position:0% +x^2 right I won't drag you through the + + + align:start position:0% +x^2 right I won't drag you through the +algebra but it's not hard to go from + + align:start position:0% +algebra but it's not hard to go from + + + align:start position:0% +algebra but it's not hard to go from +there to there this is pretty close to + + align:start position:0% +there to there this is pretty close to + + + align:start position:0% +there to there this is pretty close to +what we + + align:start position:0% +what we + + + align:start position:0% +what we +wanted we're trying to figure + + align:start position:0% +wanted we're trying to figure + + + align:start position:0% +wanted we're trying to figure +out + + align:start position:0% +out + + + align:start position:0% +out +this and we almost got + + align:start position:0% +this and we almost got + + + align:start position:0% +this and we almost got +there what do I do to finish it up + + align:start position:0% +there what do I do to finish it up + + + align:start position:0% +there what do I do to finish it up +multiply by X good so if I take this and + + align:start position:0% +multiply by X good so if I take this and + + + align:start position:0% +multiply by X good so if I take this and +multiply by + + align:start position:0% + + + + align:start position:0% + +x i = 0 to n IX to the I + + align:start position:0% +x i = 0 to n IX to the I + + + align:start position:0% +x i = 0 to n IX to the I +equals x - n + 1 x n + 1 + n x n + 2 all + + align:start position:0% +equals x - n + 1 x n + 1 + n x n + 2 all + + + align:start position:0% +equals x - n + 1 x n + 1 + n x n + 2 all +over 1 - + + align:start position:0% + + + + align:start position:0% + +x^2 okay we which should be the same + + align:start position:0% +x^2 okay we which should be the same + + + align:start position:0% +x^2 okay we which should be the same +yeah the same form that we had up there + + align:start position:0% +yeah the same form that we had up there + + + align:start position:0% +yeah the same form that we had up there +all right so that's called the + + align:start position:0% +all right so that's called the + + + align:start position:0% +all right so that's called the +derivative method you can start + + align:start position:0% +derivative method you can start + + + align:start position:0% +derivative method you can start +manipulating you treat these things as + + align:start position:0% +manipulating you treat these things as + + + align:start position:0% +manipulating you treat these things as +polinomial these sums and you start + + align:start position:0% +polinomial these sums and you start + + + align:start position:0% +polinomial these sums and you start +manipulating manipulating them like you + + align:start position:0% +manipulating manipulating them like you + + + align:start position:0% +manipulating manipulating them like you +would polinomial in fact there's a whole + + align:start position:0% +would polinomial in fact there's a whole + + + align:start position:0% +would polinomial in fact there's a whole +branch of mathematics called generating + + align:start position:0% +branch of mathematics called generating + + + align:start position:0% +branch of mathematics called generating +functions that we won't have time to do + + align:start position:0% +functions that we won't have time to do + + + align:start position:0% +functions that we won't have time to do +in this class uh that's in chapter 12 of + + align:start position:0% +in this class uh that's in chapter 12 of + + + align:start position:0% +in this class uh that's in chapter 12 of +the text but you do things like that to + + align:start position:0% +the text but you do things like that to + + + align:start position:0% +the text but you do things like that to +get sums + + align:start position:0% + + + + align:start position:0% + +any questions about what we did there + + align:start position:0% +any questions about what we did there + + + align:start position:0% +any questions about what we did there +you can also do a version where you take + + align:start position:0% +you can also do a version where you take + + + align:start position:0% +you can also do a version where you take +integrals of this if you want and then + + align:start position:0% +integrals of this if you want and then + + + align:start position:0% +integrals of this if you want and then +you get the eyes in the denominator + + align:start position:0% +you get the eyes in the denominator + + + align:start position:0% +you get the eyes in the denominator +instead of as + + align:start position:0% + + + + align:start position:0% + +coefficients for homework I think we've + + align:start position:0% +coefficients for homework I think we've + + + align:start position:0% +coefficients for homework I think we've +given + + align:start position:0% +given + + + align:start position:0% +given +you the sum of I 2 x to the + + align:start position:0% +you the sum of I 2 x to the + + + align:start position:0% +you the sum of I 2 x to the +I how do you think you're going to do + + align:start position:0% +I how do you think you're going to do + + + align:start position:0% +I how do you think you're going to do +that any thoughts about how you're going + + align:start position:0% +that any thoughts about how you're going + + + align:start position:0% +that any thoughts about how you're going +to solve that + + align:start position:0% +to solve that + + + align:start position:0% +to solve that +get the sum closed form for the sum of + + align:start position:0% +get the sum closed form for the sum of + + + align:start position:0% +get the sum closed form for the sum of +i^2 x + + align:start position:0% + + + + align:start position:0% + +i yeah do it twice take this which now + + align:start position:0% +i yeah do it twice take this which now + + + align:start position:0% +i yeah do it twice take this which now +you know take the derivative + + align:start position:0% +you know take the derivative + + + align:start position:0% +you know take the derivative +again right won't be too too + + align:start position:0% +again right won't be too too + + + align:start position:0% +again right won't be too too +hard all right + + align:start position:0% +hard all right + + + align:start position:0% +hard all right +um You can also take the version of this + + align:start position:0% +um You can also take the version of this + + + align:start position:0% +um You can also take the version of this +where n goes to + + align:start position:0% +where n goes to + + + align:start position:0% +where n goes to +Infinity let's do that + + align:start position:0% + + + + align:start position:0% + +if the absolute value of x is less than + + align:start position:0% +if the absolute value of x is less than + + + align:start position:0% +if the absolute value of x is less than +one the sum I equals one to + + align:start position:0% +one the sum I equals one to + + + align:start position:0% +one the sum I equals one to +Infinity of IX to the i what does that + + align:start position:0% +Infinity of IX to the i what does that + + + align:start position:0% +Infinity of IX to the i what does that +equal this one you can see it easier up + + align:start position:0% + + + + align:start position:0% + +here what happens when n goes to + + align:start position:0% +here what happens when n goes to + + + align:start position:0% +here what happens when n goes to +Infinity what does this + + align:start position:0% +Infinity what does this + + + align:start position:0% +Infinity what does this +do X is less than one in absolute value + + align:start position:0% +do X is less than one in absolute value + + + align:start position:0% +do X is less than one in absolute value +what happens to this as n goes to + + align:start position:0% +what happens to this as n goes to + + + align:start position:0% +what happens to this as n goes to +Infinity this + + align:start position:0% +Infinity this + + + align:start position:0% +Infinity this +term what goes to + + align:start position:0% +term what goes to + + + align:start position:0% +term what goes to +zero right this gets big but this gets + + align:start position:0% +zero right this gets big but this gets + + + align:start position:0% +zero right this gets big but this gets +smaller faster what happens to this term + + align:start position:0% +smaller faster what happens to this term + + + align:start position:0% +smaller faster what happens to this term +as n goes to + + align:start position:0% +as n goes to + + + align:start position:0% +as n goes to +Infinity same thing zero alls I'm left + + align:start position:0% +Infinity same thing zero alls I'm left + + + align:start position:0% +Infinity same thing zero alls I'm left +with is X over 1 - x^2 + + align:start position:0% + + + + align:start position:0% + +all right now this formula is useful if + + align:start position:0% +all right now this formula is useful if + + + align:start position:0% +all right now this formula is useful if +you're trying to say a value get the + + align:start position:0% +you're trying to say a value get the + + + align:start position:0% +you're trying to say a value get the +value of a company and the company is + + align:start position:0% +value of a company and the company is + + + align:start position:0% +value of a company and the company is +growing every year the company grows its + + align:start position:0% +growing every year the company grows its + + + align:start position:0% +growing every year the company grows its +bottom line by m dollars so the first + + align:start position:0% +bottom line by m dollars so the first + + + align:start position:0% +bottom line by m dollars so the first +year the company generates MLL the next + + align:start position:0% +year the company generates MLL the next + + + align:start position:0% +year the company generates MLL the next +year it generates two2 MLL in profit the + + align:start position:0% +year it generates two2 MLL in profit the + + + align:start position:0% +year it generates two2 MLL in profit the +next year is three MLL so you got an + + align:start position:0% +next year is three MLL so you got an + + + align:start position:0% +next year is three MLL so you got an +entity that every year is growing by a + + align:start position:0% +entity that every year is growing by a + + + align:start position:0% +entity that every year is growing by a +fixed amount it's not doubling every + + align:start position:0% +fixed amount it's not doubling every + + + align:start position:0% +fixed amount it's not doubling every +year but every year adds in MLL more of + + align:start position:0% +year but every year adds in MLL more of + + + align:start position:0% +year but every year adds in MLL more of +profit what would you pay to buy that + + align:start position:0% +profit what would you pay to buy that + + + align:start position:0% +profit what would you pay to buy that +company what is that worth all right so + + align:start position:0% +company what is that worth all right so + + + align:start position:0% +company what is that worth all right so +you can think of s as again an + + align:start position:0% + + + + align:start position:0% + +annuity here the + + align:start position:0% + + + + align:start position:0% + +annuity + + align:start position:0% + + + + align:start position:0% + +pays I + + align:start position:0% +pays I + + + align:start position:0% +pays I +am in this case at the + + align:start position:0% +am in this case at the + + + align:start position:0% +am in this case at the +end not the beginning say of year + + align:start position:0% +end not the beginning say of year + + + align:start position:0% +end not the beginning say of year +I + + align:start position:0% + + + + align:start position:0% + +forever this company is or this annuity + + align:start position:0% +forever this company is or this annuity + + + align:start position:0% +forever this company is or this annuity +is + + align:start position:0% +is + + + align:start position:0% +is +worth well we just plug into the + + align:start position:0% +worth well we just plug into the + + + align:start position:0% +worth well we just plug into the +formula instead of $1 each year it's m + + align:start position:0% +formula instead of $1 each year it's m + + + align:start position:0% +formula instead of $1 each year it's m +so there's an M out front X is 1 over 1 + + align:start position:0% +so there's an M out front X is 1 over 1 + + + align:start position:0% +so there's an M out front X is 1 over 1 +plus + + align:start position:0% + + + + align:start position:0% + +p and then we have oneus 1 over 1 + p^ + + align:start position:0% + + + + align:start position:0% + +2 and if we multiply the top and bottom + + align:start position:0% +2 and if we multiply the top and bottom + + + align:start position:0% +2 and if we multiply the top and bottom +by 1 + p^ + + align:start position:0% +by 1 + p^ + + + align:start position:0% +by 1 + p^ +2 we + + align:start position:0% +2 we + + + align:start position:0% +2 we +get m 1 + p over + + align:start position:0% + + + + align:start position:0% + +p^2 all right so it's possible a very + + align:start position:0% +p^2 all right so it's possible a very + + + align:start position:0% +p^2 all right so it's possible a very +simple formula to figure out how much + + align:start position:0% +simple formula to figure out how much + + + align:start position:0% +simple formula to figure out how much +you should spend to buy this company + + align:start position:0% +you should spend to buy this company + + + align:start position:0% +you should spend to buy this company +what its value is today so for example + + align:start position:0% +what its value is today so for example + + + align:start position:0% +what its value is today so for example +say the company was adding $50,000 a + + align:start position:0% +say the company was adding $50,000 a + + + align:start position:0% +say the company was adding $50,000 a +year + + align:start position:0% +year + + + align:start position:0% +year +in + + align:start position:0% +in + + + align:start position:0% +in +profit the interest rate was + + align:start position:0% +profit the interest rate was + + + align:start position:0% +profit the interest rate was +6% the value of this company is $14 + + align:start position:0% +6% the value of this company is $14 + + + align:start position:0% +6% the value of this company is $14 +million $ 14.7 + + align:start position:0% + + + + align:start position:0% + +million just plugging into that + + align:start position:0% +million just plugging into that + + + align:start position:0% +million just plugging into that +formula all right so people that do that + + align:start position:0% +formula all right so people that do that + + + align:start position:0% +formula all right so people that do that +buy companies and stuff they use + + align:start position:0% +buy companies and stuff they use + + + align:start position:0% +buy companies and stuff they use +formulas like this to figure out what + + align:start position:0% +formulas like this to figure out what + + + align:start position:0% +formulas like this to figure out what +it's worth of course you got to make + + align:start position:0% +it's worth of course you got to make + + + align:start position:0% +it's worth of course you got to make +sure it's really going to keep paying + + align:start position:0% +sure it's really going to keep paying + + + align:start position:0% +sure it's really going to keep paying +you know the $50,000 more every year and + + align:start position:0% +you know the $50,000 more every year and + + + align:start position:0% +you know the $50,000 more every year and +that this is the right interest rate to + + align:start position:0% +that this is the right interest rate to + + + align:start position:0% +that this is the right interest rate to +be thinking + + align:start position:0% +be thinking + + + align:start position:0% +be thinking +about you know and the guys on Wall + + align:start position:0% +about you know and the guys on Wall + + + align:start position:0% +about you know and the guys on Wall +Street the bankers on Wall Street + + align:start position:0% +Street the bankers on Wall Street + + + align:start position:0% +Street the bankers on Wall Street +they'll have their estimations for what + + align:start position:0% +they'll have their estimations for what + + + align:start position:0% +they'll have their estimations for what +these things you know are the value of P + + align:start position:0% +these things you know are the value of P + + + align:start position:0% +these things you know are the value of P +they would put into these + + align:start position:0% +they would put into these + + + align:start position:0% +they would put into these +formulas any questions about + + align:start position:0% +formulas any questions about + + + align:start position:0% +formulas any questions about +that + + align:start position:0% + + + + align:start position:0% + +yeah okay good all right so this one is + + align:start position:0% +yeah okay good all right so this one is + + + align:start position:0% +yeah okay good all right so this one is +okay okay I plugged x = 1 1 + P like we + + align:start position:0% +okay okay I plugged x = 1 1 + P like we + + + align:start position:0% +okay okay I plugged x = 1 1 + P like we +did before remember for the annuity + + align:start position:0% +did before remember for the annuity + + + align:start position:0% +did before remember for the annuity +because every year you're degrading it + + align:start position:0% +because every year you're degrading it + + + align:start position:0% +because every year you're degrading it +devaluing it by one over 1 plus P so + + align:start position:0% +devaluing it by one over 1 plus P so + + + align:start position:0% +devaluing it by one over 1 plus P so +that's the X + + align:start position:0% +that's the X + + + align:start position:0% +that's the X +term and it's paying uh in the E year it + + align:start position:0% +term and it's paying uh in the E year it + + + align:start position:0% +term and it's paying uh in the E year it +it's paying IM + + align:start position:0% +it's paying IM + + + align:start position:0% +it's paying IM +doll all right so the first year it pays + + align:start position:0% +doll all right so the first year it pays + + + align:start position:0% +doll all right so the first year it pays +M the next year 2m the next year 3M + + align:start position:0% +M the next year 2m the next year 3M + + + align:start position:0% +M the next year 2m the next year 3M +the next year + + align:start position:0% +the next year + + + align:start position:0% +the next year +4M but every year you're knocking it + + align:start position:0% +4M but every year you're knocking it + + + align:start position:0% +4M but every year you're knocking it +down by 1 plus 1 over P to the number of + + align:start position:0% +down by 1 plus 1 over P to the number of + + + align:start position:0% +down by 1 plus 1 over P to the number of +years so what you what you get the sum + + align:start position:0% +years so what you what you get the sum + + + align:start position:0% +years so what you what you get the sum +you've really got + + align:start position:0% + + + + align:start position:0% + +here is I equal 1 to Infinity I am + + align:start position:0% +here is I equal 1 to Infinity I am + + + align:start position:0% +here is I equal 1 to Infinity I am +dollars are paid but those dollars are + + align:start position:0% +dollars are paid but those dollars are + + + align:start position:0% +dollars are paid but those dollars are +worth one over 1 plus P to the I today + + align:start position:0% +worth one over 1 plus P to the I today + + + align:start position:0% +worth one over 1 plus P to the I today +the current value that's a good question + + align:start position:0% +the current value that's a good question + + + align:start position:0% +the current value that's a good question +I should have should have said that + + align:start position:0% +I should have should have said that + + + align:start position:0% +I should have should have said that +that's a great question all right so + + align:start position:0% +that's a great question all right so + + + align:start position:0% +that's a great question all right so +that's how we connect this up because + + align:start position:0% +that's how we connect this up because + + + align:start position:0% +that's how we connect this up because +you're getting paid this much in I years + + align:start position:0% +you're getting paid this much in I years + + + align:start position:0% +you're getting paid this much in I years +and that's worth that much degradation + + align:start position:0% +and that's worth that much degradation + + + align:start position:0% +and that's worth that much degradation +or that much devaluation today and now + + align:start position:0% +or that much devaluation today and now + + + align:start position:0% +or that much devaluation today and now +we add up the total current + + align:start position:0% +we add up the total current + + + align:start position:0% +we add up the total current +value all right so even a company that + + align:start position:0% +value all right so even a company that + + + align:start position:0% +value all right so even a company that +is paying you more and more every year + + align:start position:0% +is paying you more and more every year + + + align:start position:0% +is paying you more and more every year +still has a finite + + align:start position:0% +still has a finite + + + align:start position:0% +still has a finite +value because the extra you know the + + align:start position:0% +value because the extra you know the + + + align:start position:0% +value because the extra you know the +payments are increasing but only + + align:start position:0% +payments are increasing but only + + + align:start position:0% +payments are increasing but only +linearly the value today is decreasing + + align:start position:0% +linearly the value today is decreasing + + + align:start position:0% +linearly the value today is decreasing +geometrically and the geometric decrease + + align:start position:0% +geometrically and the geometric decrease + + + align:start position:0% +geometrically and the geometric decrease +wipes out the value of the company in + + align:start position:0% +wipes out the value of the company in + + + align:start position:0% +wipes out the value of the company in +the future yeah + + align:start position:0% + + + + align:start position:0% + +which where should I uh what did I do oh + + align:start position:0% +which where should I uh what did I do oh + + + align:start position:0% +which where should I uh what did I do oh +wait wait wait I screwed up here + + align:start position:0% +wait wait wait I screwed up here + + + align:start position:0% +wait wait wait I screwed up here +too is that what you're asking + + align:start position:0% +too is that what you're asking + + + align:start position:0% +too is that what you're asking +about yeah that's what I should have + + align:start position:0% +about yeah that's what I should have + + + align:start position:0% +about yeah that's what I should have +done right because I got 1 - x is 1 - 1 + + align:start position:0% +done right because I got 1 - x is 1 - 1 + + + align:start position:0% +done right because I got 1 - x is 1 - 1 +over 1+ P that gets squared and now when + + align:start position:0% +over 1+ P that gets squared and now when + + + align:start position:0% +over 1+ P that gets squared and now when +I multiply 1 + p^ 2 it's multiplying + + align:start position:0% +I multiply 1 + p^ 2 it's multiplying + + + align:start position:0% +I multiply 1 + p^ 2 it's multiplying +this by 1 plus p P it's 1 + P minus 1 is + + align:start position:0% +this by 1 plus p P it's 1 + P minus 1 is + + + align:start position:0% +this by 1 plus p P it's 1 + P minus 1 is +p so I have p^2 all right so this part's + + align:start position:0% +p so I have p^2 all right so this part's + + + align:start position:0% +p so I have p^2 all right so this part's +okay that part I wrote wrong that's good + + align:start position:0% +okay that part I wrote wrong that's good + + + align:start position:0% +okay that part I wrote wrong that's good +any other + + align:start position:0% + + + + align:start position:0% + +questions all + + align:start position:0% +questions all + + + align:start position:0% +questions all +right uh + + align:start position:0% + + + + align:start position:0% + +okay so let's do a simple example + + align:start position:0% + + + + align:start position:0% + +what is this + + align:start position:0% + + + + align:start position:0% + +sum a half plus 24s + 38 + + + align:start position:0% +sum a half plus 24s + 38 + + + + align:start position:0% +sum a half plus 24s + 38 + +416 forever what's that sum equal + + align:start position:0% + + + + align:start position:0% + +plug that in the + + align:start position:0% + + + + align:start position:0% + +formula uh + + align:start position:0% +formula uh + + + align:start position:0% +formula uh +y that's right + + align:start position:0% +y that's right + + + align:start position:0% +y that's right +good these + + align:start position:0% +good these + + + align:start position:0% +good these +details yeah otherwise that sum would be + + align:start position:0% +details yeah otherwise that sum would be + + + align:start position:0% +details yeah otherwise that sum would be +what if I didn't put the negative here + + align:start position:0% +what if I didn't put the negative here + + + align:start position:0% +what if I didn't put the negative here +it would be Infinity that's not so + + align:start position:0% +it would be Infinity that's not so + + + align:start position:0% +it would be Infinity that's not so +interesting the negative makes it more + + align:start position:0% +interesting the negative makes it more + + + align:start position:0% +interesting the negative makes it more +interesting so I got one over two to the + + align:start position:0% +interesting so I got one over two to the + + + align:start position:0% +interesting so I got one over two to the +ion there what's it worth + + align:start position:0% + + + + align:start position:0% + +then I can plug it in the formula what's + + align:start position:0% +then I can plug it in the formula what's + + + align:start position:0% +then I can plug it in the formula what's +x 12 so I get 12 over 1 - 12 + + align:start position:0% +x 12 so I get 12 over 1 - 12 + + + align:start position:0% +x 12 so I get 12 over 1 - 12 +squared is 12 over a quarter and that's + + align:start position:0% +squared is 12 over a quarter and that's + + + align:start position:0% +squared is 12 over a quarter and that's +two + + align:start position:0% +two + + + align:start position:0% +two +okay all + + align:start position:0% +okay all + + + align:start position:0% +okay all +right any questions on that formula + + align:start position:0% +right any questions on that formula + + + align:start position:0% +right any questions on that formula +okay it's amazing how useful these + + align:start position:0% +okay it's amazing how useful these + + + align:start position:0% +okay it's amazing how useful these +things get to be later + + align:start position:0% +things get to be later + + + align:start position:0% +things get to be later +um all right so that's sort of the + + align:start position:0% +um all right so that's sort of the + + + align:start position:0% +um all right so that's sort of the +geometric kinds of + + align:start position:0% +geometric kinds of + + + align:start position:0% +geometric kinds of +things next I want to talk about more + + align:start position:0% +things next I want to talk about more + + + align:start position:0% +things next I want to talk about more +the arithmetic kinds of sums and what + + align:start position:0% +the arithmetic kinds of sums and what + + + align:start position:0% +the arithmetic kinds of sums and what +you do + + align:start position:0% +you do + + + align:start position:0% +you do +there in fact we've already seen one + + align:start position:0% +there in fact we've already seen one + + + align:start position:0% +there in fact we've already seen one +that we've + + align:start position:0% +that we've + + + align:start position:0% +that we've +done if I sum I equals 1 to n of I I + + align:start position:0% +done if I sum I equals 1 to n of I I + + + align:start position:0% +done if I sum I equals 1 to n of I I +think we've already done this one that's + + align:start position:0% +think we've already done this one that's + + + align:start position:0% +think we've already done this one that's +just n * n + 1 / 2 probably most of you + + align:start position:0% +just n * n + 1 / 2 probably most of you + + + align:start position:0% +just n * n + 1 / 2 probably most of you +even learned that formula back in middle + + align:start position:0% +even learned that formula back in middle + + + align:start position:0% +even learned that formula back in middle +school I'm guessing maybe + + align:start position:0% +school I'm guessing maybe + + + align:start position:0% +school I'm guessing maybe +before how many people know the answer + + align:start position:0% +before how many people know the answer + + + align:start position:0% +before how many people know the answer +for this + + align:start position:0% + + + + align:start position:0% + +sum the sum of the squares the first n + + align:start position:0% +sum the sum of the squares the first n + + + align:start position:0% +sum the sum of the squares the first n +squares all right somebody knows what's + + align:start position:0% +squares all right somebody knows what's + + + align:start position:0% +squares all right somebody knows what's +what is it n * n + + + align:start position:0% +what is it n * n + + + + align:start position:0% +what is it n * n + +1 * 2 n + 1 all over 6 all right very + + align:start position:0% +1 * 2 n + 1 all over 6 all right very + + + align:start position:0% +1 * 2 n + 1 all over 6 all right very +good good that is correct all right most + + align:start position:0% +good good that is correct all right most + + + align:start position:0% +good good that is correct all right most +people don't remember that one it's a + + align:start position:0% +people don't remember that one it's a + + + align:start position:0% +people don't remember that one it's a +little harder to + + align:start position:0% +little harder to + + + align:start position:0% +little harder to +derive um how would you prove + + align:start position:0% +derive um how would you prove + + + align:start position:0% +derive um how would you prove +this by induction unfortunately + + align:start position:0% +this by induction unfortunately + + + align:start position:0% +this by induction unfortunately +induction doesn't tell you how to + + align:start position:0% +induction doesn't tell you how to + + + align:start position:0% +induction doesn't tell you how to +remember what the formula was and + + align:start position:0% +remember what the formula was and + + + align:start position:0% +remember what the formula was and +there's a couple of ways you can go + + align:start position:0% +there's a couple of ways you can go + + + align:start position:0% +there's a couple of ways you can go +about that one is you could remember or + + align:start position:0% +about that one is you could remember or + + + align:start position:0% +about that one is you could remember or +guess that the answer is a polinomial in + + align:start position:0% +guess that the answer is a polinomial in + + + align:start position:0% +guess that the answer is a polinomial in +n in fact because you're summing squares + + align:start position:0% +n in fact because you're summing squares + + + align:start position:0% +n in fact because you're summing squares +you might guess that it's a cubic + + align:start position:0% +you might guess that it's a cubic + + + align:start position:0% +you might guess that it's a cubic +polinomial inet and if you remember just + + align:start position:0% +polinomial inet and if you remember just + + + align:start position:0% +polinomial inet and if you remember just +that or guess just that then you could + + align:start position:0% +that or guess just that then you could + + + align:start position:0% +that or guess just that then you could +actually plug in values and get the + + align:start position:0% +actually plug in values and get the + + + align:start position:0% +actually plug in values and get the +answer and this is you know a common + + align:start position:0% +answer and this is you know a common + + + align:start position:0% +answer and this is you know a common +method of solving these sums is you sort + + align:start position:0% +method of solving these sums is you sort + + + align:start position:0% +method of solving these sums is you sort +of guess the form of the solution in + + align:start position:0% +of guess the form of the solution in + + + align:start position:0% +of guess the form of the solution in +this + + align:start position:0% +this + + + align:start position:0% +this +case you might + + align:start position:0% + + + + align:start position:0% + +guess that for all n the sum I = 1 to n + + align:start position:0% +guess that for all n the sum I = 1 to n + + + align:start position:0% +guess that for all n the sum I = 1 to n +of i^2 + + align:start position:0% +of i^2 + + + align:start position:0% +of i^2 +equals a + + align:start position:0% + + + + align:start position:0% + +cubic and then what you would do is plug + + align:start position:0% +cubic and then what you would do is plug + + + align:start position:0% +cubic and then what you would do is plug +in the value + + align:start position:0% +in the value + + + align:start position:0% +in the value +Nal 1 Nal 2 maybe even we'll make it n + + align:start position:0% +Nal 1 Nal 2 maybe even we'll make it n + + + align:start position:0% +Nal 1 Nal 2 maybe even we'll make it n +equals Zer make it simple and start + + align:start position:0% +equals Zer make it simple and start + + + align:start position:0% +equals Zer make it simple and start +getting some constraints on the + + align:start position:0% +getting some constraints on the + + + align:start position:0% +getting some constraints on the +coefficients so you would plug + + align:start position:0% + + + + align:start position:0% + +in N equal 0 + + align:start position:0% +in N equal 0 + + + align:start position:0% +in N equal 0 +the sum is + + align:start position:0% + + + + align:start position:0% + +zero the polinomial evaluates to + + align:start position:0% +zero the polinomial evaluates to + + + align:start position:0% +zero the polinomial evaluates to +D that tells you what D's got to be + + align:start position:0% +D that tells you what D's got to be + + + align:start position:0% +D that tells you what D's got to be +right away n equals 1 the sum is one and + + align:start position:0% +right away n equals 1 the sum is one and + + + align:start position:0% +right away n equals 1 the sum is one and +when you plug into the polinomial you + + align:start position:0% +when you plug into the polinomial you + + + align:start position:0% +when you plug into the polinomial you +get a plus b plus C plus + + align:start position:0% +get a plus b plus C plus + + + align:start position:0% +get a plus b plus C plus +d n equal + + align:start position:0% +d n equal + + + align:start position:0% +d n equal +2 well that's 1 + 4 is + + align:start position:0% +2 well that's 1 + 4 is + + + align:start position:0% +2 well that's 1 + 4 is +5 2 cubed is 8 so you have8 8 a + 4 b + + + align:start position:0% +5 2 cubed is 8 so you have8 8 a + 4 b + + + + align:start position:0% +5 2 cubed is 8 so you have8 8 a + 4 b + +2 C + D and you'll need one more since + + align:start position:0% +2 C + D and you'll need one more since + + + align:start position:0% +2 C + D and you'll need one more since +you got four + + align:start position:0% +you got four + + + align:start position:0% +you got four +variables let's see 1 + 4 + 9 is + + align:start position:0% +variables let's see 1 + 4 + 9 is + + + align:start position:0% +variables let's see 1 + 4 + 9 is +14 uh I've now got 3 cubed is 27 a plus + + align:start position:0% +14 uh I've now got 3 cubed is 27 a plus + + + align:start position:0% +14 uh I've now got 3 cubed is 27 a plus +uh 9 b + 3 C + + + align:start position:0% +uh 9 b + 3 C + + + + align:start position:0% +uh 9 b + 3 C + +D so now I got four equations and four + + align:start position:0% +D so now I got four equations and four + + + align:start position:0% +D so now I got four equations and four +variables and with any luck I can solve + + align:start position:0% +variables and with any luck I can solve + + + align:start position:0% +variables and with any luck I can solve +that system of equations and get the + + align:start position:0% +that system of equations and get the + + + align:start position:0% +that system of equations and get the +answer and in fact you can when you + + align:start position:0% +answer and in fact you can when you + + + align:start position:0% +answer and in fact you can when you +solve this system you get AAL + + align:start position:0% +solve this system you get AAL + + + align:start position:0% +solve this system you get AAL +1/3 B = 12 c = 1 16 and D equal 0 and + + align:start position:0% +1/3 B = 12 c = 1 16 and D equal 0 and + + + align:start position:0% +1/3 B = 12 c = 1 16 and D equal 0 and +that's exactly what you get in that + + align:start position:0% +that's exactly what you get in that + + + align:start position:0% +that's exactly what you get in that +formula so that's a way to reproduce the + + align:start position:0% +formula so that's a way to reproduce the + + + align:start position:0% +formula so that's a way to reproduce the +formula if you forgot + + align:start position:0% +formula if you forgot + + + align:start position:0% +formula if you forgot +it uh now this method really to be sure + + align:start position:0% +it uh now this method really to be sure + + + align:start position:0% +it uh now this method really to be sure +you got the right answer you got to go + + align:start position:0% +you got the right answer you got to go + + + align:start position:0% +you got the right answer you got to go +prove it by induction because I didn't D + + align:start position:0% +prove it by induction because I didn't D + + + align:start position:0% +prove it by induction because I didn't D +I didn't I derived the answer if it was + + align:start position:0% +I didn't I derived the answer if it was + + + align:start position:0% +I didn't I derived the answer if it was +a polinomial I would have gotten it + + align:start position:0% +a polinomial I would have gotten it + + + align:start position:0% +a polinomial I would have gotten it +right but I might be wrong in my guess + + align:start position:0% +right but I might be wrong in my guess + + + align:start position:0% +right but I might be wrong in my guess +and to make sure your guess is right you + + align:start position:0% +and to make sure your guess is right you + + + align:start position:0% +and to make sure your guess is right you +got to go back and use induction to + + align:start position:0% +got to go back and use induction to + + + align:start position:0% +got to go back and use induction to +prove it for this approach + + align:start position:0% + + + + align:start position:0% + +yeah well it turns out that anytime + + align:start position:0% +yeah well it turns out that anytime + + + align:start position:0% +yeah well it turns out that anytime +you're summing Powers the answer is a + + align:start position:0% +you're summing Powers the answer is a + + + align:start position:0% +you're summing Powers the answer is a +polinomial to one higher + + align:start position:0% +polinomial to one higher + + + align:start position:0% +polinomial to one higher +degree so if you just remembered that + + align:start position:0% +degree so if you just remembered that + + + align:start position:0% +degree so if you just remembered that +fact or you guessed that fact another + + align:start position:0% +fact or you guessed that fact another + + + align:start position:0% +fact or you guessed that fact another +way to sort of Imagine That might be + + align:start position:0% +way to sort of Imagine That might be + + + align:start position:0% +way to sort of Imagine That might be +true + + align:start position:0% +true + + + align:start position:0% +true +is that you know I'm getting n of them + + align:start position:0% +is that you know I'm getting n of them + + + align:start position:0% +is that you know I'm getting n of them +so I might be multiplying and the top + + align:start position:0% +so I might be multiplying and the top + + + align:start position:0% +so I might be multiplying and the top +one is n^ s so I'm going to have n of + + align:start position:0% +one is n^ s so I'm going to have n of + + + align:start position:0% +one is n^ s so I'm going to have n of +them about n s may be something like n + + align:start position:0% +them about n s may be something like n + + + align:start position:0% +them about n s may be something like n +cubed um that's another way you know you + + align:start position:0% +cubed um that's another way you know you + + + align:start position:0% +cubed um that's another way you know you +could think of it to Guess + + align:start position:0% +could think of it to Guess + + + align:start position:0% +could think of it to Guess +that any other + + align:start position:0% +that any other + + + align:start position:0% +that any other +questions on + + align:start position:0% +questions on + + + align:start position:0% +questions on +this + + align:start position:0% +this + + + align:start position:0% +this +okay all right so far all these sums had + + align:start position:0% +okay all right so far all these sums had + + + align:start position:0% +okay all right so far all these sums had +nice Clos forms and a lot of them do + + align:start position:0% +nice Clos forms and a lot of them do + + + align:start position:0% +nice Clos forms and a lot of them do +that you'll encounter later on but not + + align:start position:0% +that you'll encounter later on but not + + + align:start position:0% +that you'll encounter later on but not +all and sometimes you get sums that + + align:start position:0% +all and sometimes you get sums that + + + align:start position:0% +all and sometimes you get sums that +don't have a nice closed form at least + + align:start position:0% +don't have a nice closed form at least + + + align:start position:0% +don't have a nice closed form at least +nobody's ever figured out one and + + align:start position:0% +nobody's ever figured out one and + + + align:start position:0% +nobody's ever figured out one and +probably doesn't always exist for + + align:start position:0% +probably doesn't always exist for + + + align:start position:0% +probably doesn't always exist for +example what if I want to sum the first + + align:start position:0% +example what if I want to sum the first + + + align:start position:0% +example what if I want to sum the first +n square roots of + + align:start position:0% + + + + align:start position:0% + +integers let's write that down + + align:start position:0% + + + + align:start position:0% + +so say I want a closed form for this + + align:start position:0% + + + + align:start position:0% + +guy you know nobody knows an answer for + + align:start position:0% +guy you know nobody knows an answer for + + + align:start position:0% +guy you know nobody knows an answer for +that but there are ways of getting very + + align:start position:0% +that but there are ways of getting very + + + align:start position:0% +that but there are ways of getting very +good close bounds on it that are closed + + align:start position:0% +good close bounds on it that are closed + + + align:start position:0% +good close bounds on it that are closed +for and these are very important we're + + align:start position:0% +for and these are very important we're + + + align:start position:0% +for and these are very important we're +going to use this the rest of today and + + align:start position:0% +going to use this the rest of today and + + + align:start position:0% +going to use this the rest of today and +the rest of next time + + align:start position:0% +the rest of next time + + + align:start position:0% +the rest of next time +uh and they're based on replacing the + + align:start position:0% +uh and they're based on replacing the + + + align:start position:0% +uh and they're based on replacing the +sum with an integral and the integral is + + align:start position:0% +sum with an integral and the integral is + + + align:start position:0% +sum with an integral and the integral is +very close to the right answer and then + + align:start position:0% +very close to the right answer and then + + + align:start position:0% +very close to the right answer and then +we can see what the error terms are so + + align:start position:0% +we can see what the error terms are so + + + align:start position:0% +we can see what the error terms are so +let's first look at the case when we've + + align:start position:0% +let's first look at the case when we've + + + align:start position:0% +let's first look at the case when we've +got a sum where the terms are increasing + + align:start position:0% +got a sum where the terms are increasing + + + align:start position:0% +got a sum where the terms are increasing +as I + + align:start position:0% + + + + align:start position:0% + +grows all right and these we'll call + + align:start position:0% +grows all right and these we'll call + + + align:start position:0% +grows all right and these we'll call +these integration + + align:start position:0% + + + + align:start position:0% + +bounds and a general sum will look like + + align:start position:0% +bounds and a general sum will look like + + + align:start position:0% +bounds and a general sum will look like +this I 1 to n of f of + + align:start position:0% +this I 1 to n of f of + + + align:start position:0% +this I 1 to n of f of +I and the first case is when f is a + + align:start position:0% +I and the first case is when f is a + + + align:start position:0% +I and the first case is when f is a +positive increasing + + align:start position:0% + + + + align:start position:0% + +function increasing in + + align:start position:0% + + + + align:start position:0% + +I right ration bounds and so we're + + align:start position:0% +I right ration bounds and so we're + + + align:start position:0% +I right ration bounds and so we're +increasing function + + align:start position:0% + + + + align:start position:0% + +all right so let me draw a picture + + align:start position:0% +all right so let me draw a picture + + + align:start position:0% +all right so let me draw a picture +that'll + + align:start position:0% +that'll + + + align:start position:0% +that'll +hopefully make the bounds we're going to + + align:start position:0% +hopefully make the bounds we're going to + + + align:start position:0% +hopefully make the bounds we're going to +get pretty + + align:start position:0% + + + + align:start position:0% + +easy so let's + + align:start position:0% +easy so let's + + + align:start position:0% +easy so let's +draw the sum here as follows I got 0 1 2 + + align:start position:0% +draw the sum here as follows I got 0 1 2 + + + align:start position:0% +draw the sum here as follows I got 0 1 2 + + align:start position:0% + + + + align:start position:0% + +N - 2 N + + align:start position:0% +N - 2 N + + + align:start position:0% +N - 2 N +-1 + + align:start position:0% +-1 + + + align:start position:0% +-1 +n and draw the values of f here here's F + + align:start position:0% +n and draw the values of f here here's F + + + align:start position:0% +n and draw the values of f here here's F +of + + align:start position:0% +of + + + align:start position:0% +of +one F of two it's + + align:start position:0% +one F of two it's + + + align:start position:0% +one F of two it's +increasing F of + + align:start position:0% + + + + align:start position:0% + +three F of n minus one and F of + + align:start position:0% + + + + align:start position:0% + +n then I'll draw + + align:start position:0% +n then I'll draw + + + align:start position:0% +n then I'll draw +the rect angles + + align:start position:0% + + + + align:start position:0% + +here so this has + + align:start position:0% +here so this has + + + align:start position:0% +here so this has +area of f of one this has area F of two + + align:start position:0% +area of f of one this has area F of two + + + align:start position:0% +area of f of one this has area F of two +this has area F of + + align:start position:0% +this has area F of + + + align:start position:0% +this has area F of +three and we keep on + + align:start position:0% +three and we keep on + + + align:start position:0% +three and we keep on +going see this will be F of n minus two + + align:start position:0% +going see this will be F of n minus two + + + align:start position:0% +going see this will be F of n minus two +on this one I'll just do F of n minus + + align:start position:0% +on this one I'll just do F of n minus + + + align:start position:0% +on this one I'll just do F of n minus +one draw this guy + + align:start position:0% + + + + align:start position:0% + +here so it's unit width its height is f + + align:start position:0% +here so it's unit width its height is f + + + align:start position:0% +here so it's unit width its height is f +of n minus one so so it's area is f of n + + align:start position:0% +of n minus one so so it's area is f of n + + + align:start position:0% +of n minus one so so it's area is f of n +minus one and + + align:start position:0% +minus one and + + + align:start position:0% +minus one and +then F of + + align:start position:0% + + + + align:start position:0% + +n all right and let me also so the the + + align:start position:0% +n all right and let me also so the the + + + align:start position:0% +n all right and let me also so the the +sum of f ofi is the areas in the + + align:start position:0% +sum of f ofi is the areas in the + + + align:start position:0% +sum of f ofi is the areas in the +rectangles that's what the sum is and I + + align:start position:0% +rectangles that's what the sum is and I + + + align:start position:0% +rectangles that's what the sum is and I +want to get bounds on this sum using the + + align:start position:0% +want to get bounds on this sum using the + + + align:start position:0% +want to get bounds on this sum using the +integral because integrals are easier to + + align:start position:0% +integral because integrals are easier to + + + align:start position:0% +integral because integrals are easier to +compute so let's draw the + + align:start position:0% +compute so let's draw the + + + align:start position:0% +compute so let's draw the +function F ofx from 1 to + + align:start position:0% + + + + align:start position:0% + +n all right so this is f ofx as a + + align:start position:0% +n all right so this is f ofx as a + + + align:start position:0% +n all right so this is f ofx as a +function now I + + align:start position:0% +function now I + + + align:start position:0% +function now I +claim that the + + align:start position:0% +claim that the + + + align:start position:0% +claim that the +sum I = 1 to n of f of + + align:start position:0% +sum I = 1 to n of f of + + + align:start position:0% +sum I = 1 to n of f of +I is at least F of 1 plus the integral + + align:start position:0% +I is at least F of 1 plus the integral + + + align:start position:0% +I is at least F of 1 plus the integral +from 1 to n + + align:start position:0% +from 1 to n + + + align:start position:0% +from 1 to n +F ofx + + align:start position:0% + + + + align:start position:0% + +DX now the integral from 1 to n of f + + align:start position:0% +DX now the integral from 1 to n of f + + + align:start position:0% +DX now the integral from 1 to n of f +ofx is this stuff the stuff under the + + align:start position:0% +ofx is this stuff the stuff under the + + + align:start position:0% +ofx is this stuff the stuff under the +curve all right comes down here starts + + align:start position:0% +curve all right comes down here starts + + + align:start position:0% +curve all right comes down here starts +at one and it's a stuff under the + + align:start position:0% +at one and it's a stuff under the + + + align:start position:0% +at one and it's a stuff under the +curve and what I'm saying here is that + + align:start position:0% +curve and what I'm saying here is that + + + align:start position:0% +curve and what I'm saying here is that +if you take that stuff under the curve + + align:start position:0% +if you take that stuff under the curve + + + align:start position:0% +if you take that stuff under the curve +and add F of one which is this piece + + align:start position:0% +and add F of one which is this piece + + + align:start position:0% +and add F of one which is this piece +that's a lower bound on our sum the + + align:start position:0% +that's a lower bound on our sum the + + + align:start position:0% +that's a lower bound on our sum the +sum's bigger than + + align:start position:0% +sum's bigger than + + + align:start position:0% +sum's bigger than +that all right so what I'm saying is the + + align:start position:0% +that all right so what I'm saying is the + + + align:start position:0% +that all right so what I'm saying is the +area in the + + align:start position:0% +area in the + + + align:start position:0% +area in the +rectangles is at least as big as the + + align:start position:0% +rectangles is at least as big as the + + + align:start position:0% +rectangles is at least as big as the +area in the first rectangle plus the + + align:start position:0% +area in the first rectangle plus the + + + align:start position:0% +area in the first rectangle plus the +area under the + + align:start position:0% +area under the + + + align:start position:0% +area under the +curve does everybody see why that + + align:start position:0% +curve does everybody see why that + + + align:start position:0% +curve does everybody see why that +is all right I'm saying the sum is the + + align:start position:0% +is all right I'm saying the sum is the + + + align:start position:0% +is all right I'm saying the sum is the +area in the + + align:start position:0% +area in the + + + align:start position:0% +area in the +rectangles all right that's pretty clear + + align:start position:0% +rectangles all right that's pretty clear + + + align:start position:0% +rectangles all right that's pretty clear +and that is at least as big as the first + + align:start position:0% +and that is at least as big as the first + + + align:start position:0% +and that is at least as big as the first +rectangle F of one plus the stuff under + + align:start position:0% +rectangle F of one plus the stuff under + + + align:start position:0% +rectangle F of one plus the stuff under +the curve which is the integral and I've + + align:start position:0% +the curve which is the integral and I've + + + align:start position:0% +the curve which is the integral and I've +left I've chopped off these guys that's + + align:start position:0% +left I've chopped off these guys that's + + + align:start position:0% +left I've chopped off these guys that's +extra + + align:start position:0% +extra + + + align:start position:0% +extra +okay is that all right it's a lower + + align:start position:0% +okay is that all right it's a lower + + + align:start position:0% +okay is that all right it's a lower +bound any questions on the lower bound + + align:start position:0% +bound any questions on the lower bound + + + align:start position:0% +bound any questions on the lower bound +this is a picture proof right which we + + align:start position:0% +this is a picture proof right which we + + + align:start position:0% +this is a picture proof right which we +always tell you not to do but we're + + align:start position:0% +always tell you not to do but we're + + + align:start position:0% +always tell you not to do but we're +going to do one here + + align:start position:0% +going to do one here + + + align:start position:0% +going to do one here +uh and of course it totally hides what H + + align:start position:0% +uh and of course it totally hides what H + + + align:start position:0% +uh and of course it totally hides what H +you know why did I need f is increasing + + align:start position:0% +you know why did I need f is increasing + + + align:start position:0% +you know why did I need f is increasing +but we'll see that in a minute the proof + + align:start position:0% +but we'll see that in a minute the proof + + + align:start position:0% +but we'll see that in a minute the proof +would not work unless it is increasing + + align:start position:0% +would not work unless it is increasing + + + align:start position:0% +would not work unless it is increasing +here all + + align:start position:0% +here all + + + align:start position:0% +here all +right any questions because now I'm + + align:start position:0% +right any questions because now I'm + + + align:start position:0% +right any questions because now I'm +going to do the other bound the other + + align:start position:0% +going to do the other bound the other + + + align:start position:0% +going to do the other bound the other +side right I also claim this will be a + + align:start position:0% +side right I also claim this will be a + + + align:start position:0% +side right I also claim this will be a +little trickier to see that the + + align:start position:0% +little trickier to see that the + + + align:start position:0% +little trickier to see that the +sum is at most F of n plus the integral + + align:start position:0% +sum is at most F of n plus the integral + + + align:start position:0% +sum is at most F of n plus the integral +from 1 to + + align:start position:0% + + + + align:start position:0% + +n all right so this is the lower bound + + align:start position:0% +n all right so this is the lower bound + + + align:start position:0% +n all right so this is the lower bound +add in F of one the upper bound just add + + align:start position:0% +add in F of one the upper bound just add + + + align:start position:0% +add in F of one the upper bound just add +an F of n so let's see why that's + + align:start position:0% +an F of n so let's see why that's + + + align:start position:0% +an F of n so let's see why that's +true now to see that this is I'm not + + align:start position:0% +true now to see that this is I'm not + + + align:start position:0% +true now to see that this is I'm not +going to be able to draw + + align:start position:0% +going to be able to draw + + + align:start position:0% +going to be able to draw +it I want you to imagine taking this + + align:start position:0% +it I want you to imagine taking this + + + align:start position:0% +it I want you to imagine taking this +this curve and the area under it down to + + align:start position:0% +this curve and the area under it down to + + + align:start position:0% +this curve and the area under it down to +here and sliding it left one + + align:start position:0% +here and sliding it left one + + + align:start position:0% +here and sliding it left one +unit all right sliding it + + align:start position:0% +unit all right sliding it + + + align:start position:0% +unit all right sliding it +left to here sliding it left one unit + + align:start position:0% +left to here sliding it left one unit + + + align:start position:0% +left to here sliding it left one unit +over to here + + align:start position:0% + + + + align:start position:0% + +now when I slide it left one unit did + + align:start position:0% +now when I slide it left one unit did + + + align:start position:0% +now when I slide it left one unit did +the area under it + + align:start position:0% +the area under it + + + align:start position:0% +the area under it +change no it's the same area under it + + align:start position:0% +change no it's the same area under it + + + align:start position:0% +change no it's the same area under it +just where it sits on the picture is now + + align:start position:0% +just where it sits on the picture is now + + + align:start position:0% +just where it sits on the picture is now +out + + align:start position:0% + + + + align:start position:0% + +here all right it's this area under this + + align:start position:0% +here all right it's this area under this + + + align:start position:0% +here all right it's this area under this +guy but it's the same thing it's the + + align:start position:0% +guy but it's the same thing it's the + + + align:start position:0% +guy but it's the same thing it's the +same + + align:start position:0% +same + + + align:start position:0% +same +integral and you can see that it's more + + align:start position:0% +integral and you can see that it's more + + + align:start position:0% +integral and you can see that it's more +than what's in these rectangles because + + align:start position:0% +than what's in these rectangles because + + + align:start position:0% +than what's in these rectangles because +I got all this + + align:start position:0% +I got all this + + + align:start position:0% +I got all this +stuff and of course I didn't even + + align:start position:0% +stuff and of course I didn't even + + + align:start position:0% +stuff and of course I didn't even +include this so now I add the + + align:start position:0% + + + + align:start position:0% + +FN so if I take the area under the curve + + align:start position:0% +FN so if I take the area under the curve + + + align:start position:0% +FN so if I take the area under the curve +which is the integral shifted left one + + align:start position:0% +which is the integral shifted left one + + + align:start position:0% +which is the integral shifted left one +so it only goes up to here now and then + + align:start position:0% +so it only goes up to here now and then + + + align:start position:0% +so it only goes up to here now and then +add in this + + align:start position:0% +add in this + + + align:start position:0% +add in this +rectangle that dominates the area in the + + align:start position:0% +rectangle that dominates the area in the + + + align:start position:0% +rectangle that dominates the area in the +rectangles bigger + + align:start position:0% + + + + align:start position:0% + +than all right you you see + + align:start position:0% + + + + align:start position:0% + +that I could do a lot of equations on + + align:start position:0% +that I could do a lot of equations on + + + align:start position:0% +that I could do a lot of equations on +the board but for sure that would be + + align:start position:0% +the board but for sure that would be + + + align:start position:0% +the board but for sure that would be +hopeless to follow uh any questions + + align:start position:0% +hopeless to follow uh any questions + + + align:start position:0% +hopeless to follow uh any questions +about this + + align:start position:0% + + + + align:start position:0% + +yeah + + align:start position:0% + + + + align:start position:0% + +yeah is there is a lot of hand waving or + + align:start position:0% +yeah is there is a lot of hand waving or + + + align:start position:0% +yeah is there is a lot of hand waving or +am I just + + align:start position:0% + + + + align:start position:0% + +always yeah there's a little hand waving + + align:start position:0% +always yeah there's a little hand waving + + + align:start position:0% +always yeah there's a little hand waving +going on uh but I do believe it it's + + align:start position:0% +going on uh but I do believe it it's + + + align:start position:0% +going on uh but I do believe it it's +true we can with equations you can make + + align:start position:0% +true we can with equations you can make + + + align:start position:0% +true we can with equations you can make +it precise so let's look at it again do + + align:start position:0% +it precise so let's look at it again do + + + align:start position:0% +it precise so let's look at it again do +the this one more + + align:start position:0% +the this one more + + + align:start position:0% +the this one more +time yeah I'm waving hands a little bit + + align:start position:0% +time yeah I'm waving hands a little bit + + + align:start position:0% +time yeah I'm waving hands a little bit +but but it also hopefully the intuition + + align:start position:0% +but but it also hopefully the intuition + + + align:start position:0% +but but it also hopefully the intuition +comes across + + align:start position:0% +comes across + + + align:start position:0% +comes across +because when I shift left by one this + + align:start position:0% +because when I shift left by one this + + + align:start position:0% +because when I shift left by one this +point becomes this point that point + + align:start position:0% +point becomes this point that point + + + align:start position:0% +point becomes this point that point +becomes that point and I'm catching the + + align:start position:0% +becomes that point and I'm catching the + + + align:start position:0% +becomes that point and I'm catching the +sort of the cusp of these rectangles and + + align:start position:0% +sort of the cusp of these rectangles and + + + align:start position:0% +sort of the cusp of these rectangles and +now I take this curve + + align:start position:0% +now I take this curve + + + align:start position:0% +now I take this curve +here Shifting the whole curve left one + + align:start position:0% +here Shifting the whole curve left one + + + align:start position:0% +here Shifting the whole curve left one +unit + + align:start position:0% +unit + + + align:start position:0% +unit +and the area doesn't + + align:start position:0% +and the area doesn't + + + align:start position:0% +and the area doesn't +change it would be equivalent of taking + + align:start position:0% +change it would be equivalent of taking + + + align:start position:0% +change it would be equivalent of taking +the integral from 0 to n minus one you + + align:start position:0% +the integral from 0 to n minus one you + + + align:start position:0% +the integral from 0 to n minus one you +know is what I'm doing of f ofx + one + + align:start position:0% +know is what I'm doing of f ofx + one + + + align:start position:0% +know is what I'm doing of f ofx + one +right there another way to look at it + + align:start position:0% +right there another way to look at it + + + align:start position:0% +right there another way to look at it +mathematically maybe probably the formal + + align:start position:0% +mathematically maybe probably the formal + + + align:start position:0% +mathematically maybe probably the formal +way to do it but the idea is that this + + align:start position:0% +way to do it but the idea is that this + + + align:start position:0% +way to do it but the idea is that this +now contains all these first n minus one + + align:start position:0% +now contains all these first n minus one + + + align:start position:0% +now contains all these first n minus one +rectangles are contained underneath it + + align:start position:0% +rectangles are contained underneath it + + + align:start position:0% +rectangles are contained underneath it +and then I just add this + + align:start position:0% +and then I just add this + + + align:start position:0% +and then I just add this +in and I'm ready to I'm good to go I've + + align:start position:0% +in and I'm ready to I'm good to go I've + + + align:start position:0% +in and I'm ready to I'm good to go I've +contained all the rectangles now for the + + align:start position:0% +contained all the rectangles now for the + + + align:start position:0% +contained all the rectangles now for the +upper + + align:start position:0% +upper + + + align:start position:0% +upper +bound all right mathematically what this + + align:start position:0% +bound all right mathematically what this + + + align:start position:0% +bound all right mathematically what this +is this curve is 0 to n minus one FX + + + align:start position:0% +is this curve is 0 to n minus one FX + + + + align:start position:0% +is this curve is 0 to n minus one FX + +one which is the same thing as what that + + align:start position:0% +one which is the same thing as what that + + + align:start position:0% +one which is the same thing as what that +is okay any any + + align:start position:0% +is okay any any + + + align:start position:0% +is okay any any +questions for + + align:start position:0% +questions for + + + align:start position:0% +questions for +that all right but now I have good + + align:start position:0% +that all right but now I have good + + + align:start position:0% +that all right but now I have good +bounds on the + + align:start position:0% +bounds on the + + + align:start position:0% +bounds on the +sum right we know that the sum is at + + align:start position:0% +sum right we know that the sum is at + + + align:start position:0% +sum right we know that the sum is at +least this and at most + + align:start position:0% +least this and at most + + + align:start position:0% +least this and at most +that and those two bounds only differ by + + align:start position:0% +that and those two bounds only differ by + + + align:start position:0% +that and those two bounds only differ by +a single + + align:start position:0% +a single + + + align:start position:0% +a single +term in the sum so they're very close + + align:start position:0% +term in the sum so they're very close + + + align:start position:0% +term in the sum so they're very close +right and these actually are good + + align:start position:0% +right and these actually are good + + + align:start position:0% +right and these actually are good +formulas to write down for your crib + + align:start position:0% +formulas to write down for your crib + + + align:start position:0% +formulas to write down for your crib +sheet that is worth + + align:start position:0% +sheet that is worth + + + align:start position:0% +sheet that is worth +doing on the + + align:start position:0% +doing on the + + + align:start position:0% +doing on the +test and we'll use them more today and + + align:start position:0% +test and we'll use them more today and + + + align:start position:0% +test and we'll use them more today and +we'll also use them on Thursday + + align:start position:0% + + + + align:start position:0% + +okay so now we can actually get close + + align:start position:0% +okay so now we can actually get close + + + align:start position:0% +okay so now we can actually get close +bounds on the sum of the square + + align:start position:0% +bounds on the sum of the square + + + align:start position:0% +bounds on the sum of the square +roots all right so let's see how this + + align:start position:0% +roots all right so let's see how this + + + align:start position:0% +roots all right so let's see how this +works + + align:start position:0% +works + + + align:start position:0% +works +for f of I equal the root of I which is + + align:start position:0% +for f of I equal the root of I which is + + + align:start position:0% +for f of I equal the root of I which is +increasing so I compute the integral + + align:start position:0% +increasing so I compute the integral + + + align:start position:0% +increasing so I compute the integral +from one to n of square root of x + + align:start position:0% +from one to n of square root of x + + + align:start position:0% +from one to n of square root of x +DX and that's just X the 3es over three + + align:start position:0% +DX and that's just X the 3es over three + + + align:start position:0% +DX and that's just X the 3es over three +halves evaluated at n and + + align:start position:0% +halves evaluated at n and + + + align:start position:0% +halves evaluated at n and +one and that just equals 23 + + align:start position:0% +one and that just equals 23 + + + align:start position:0% +one and that just equals 23 +thir and the 3us + + align:start position:0% +thir and the 3us + + + align:start position:0% +thir and the 3us +one and now I can compute the bounds on + + align:start position:0% +one and now I can compute the bounds on + + + align:start position:0% +one and now I can compute the bounds on +the sum of the first n square + + align:start position:0% +the sum of the first n square + + + align:start position:0% +the sum of the first n square +roots all right so I know that square + + align:start position:0% +roots all right so I know that square + + + align:start position:0% +roots all right so I know that square +root I = 1 to + + align:start position:0% + + + + align:start position:0% + +n well the upper bound is + + align:start position:0% +n well the upper bound is + + + align:start position:0% +n well the upper bound is +FN plus the integral + + align:start position:0% + + + + align:start position:0% + +and the lower bound is f of + + align:start position:0% +and the lower bound is f of + + + align:start position:0% +and the lower bound is f of +one plus the + + align:start position:0% + + + + align:start position:0% + +integral what is f of + + align:start position:0% + + + + align:start position:0% + +n that's the square root of + + align:start position:0% +n that's the square root of + + + align:start position:0% +n that's the square root of +n what is f of + + align:start position:0% +n what is f of + + + align:start position:0% +n what is f of +one square root of one which is + + align:start position:0% +one square root of one which is + + + align:start position:0% +one square root of one which is +one all right so I'll plug that in here + + align:start position:0% +one all right so I'll plug that in here + + + align:start position:0% +one all right so I'll plug that in here +I get 2/3 + + align:start position:0% +I get 2/3 + + + align:start position:0% +I get 2/3 +and the + + align:start position:0% +and the + + + align:start position:0% +and the +3 + 1 - 2/3 is plus + + align:start position:0% + + + + align:start position:0% + +A3 and here I get + + align:start position:0% +A3 and here I get + + + align:start position:0% +A3 and here I get +2/3 n the + + align:start position:0% +2/3 n the + + + align:start position:0% +2/3 n the +3es plus the < TK of n minus + + align:start position:0% + + + + align:start position:0% + +2/3 all right so now I have pretty good + + align:start position:0% +2/3 all right so now I have pretty good + + + align:start position:0% +2/3 all right so now I have pretty good +bounds on the sum of the first n square + + align:start position:0% +bounds on the sum of the first n square + + + align:start position:0% +bounds on the sum of the first n square +roots using this + + align:start position:0% +roots using this + + + align:start position:0% +roots using this +method so for example take n equal + + align:start position:0% + + + + align:start position:0% + +100 this number evaluates to + + align:start position:0% +100 this number evaluates to + + + align:start position:0% +100 this number evaluates to +667 this number evaluates to + + align:start position:0% +667 this number evaluates to + + + align:start position:0% +667 this number evaluates to +676 and the difference is N9 which is + + align:start position:0% +676 and the difference is N9 which is + + + align:start position:0% +676 and the difference is N9 which is +the square root of 100 minus + + align:start position:0% +the square root of 100 minus + + + align:start position:0% +the square root of 100 minus +one this is square root of n this is one + + align:start position:0% +one this is square root of n this is one + + + align:start position:0% +one this is square root of n this is one +so the Gap here isun of n minus one and + + align:start position:0% +so the Gap here isun of n minus one and + + + align:start position:0% +so the Gap here isun of n minus one and +Nal 100 Ro of 100 - 1 is 9 so I + + align:start position:0% +Nal 100 Ro of 100 - 1 is 9 so I + + + align:start position:0% +Nal 100 Ro of 100 - 1 is 9 so I +shouldn't be surprised my Gap here is + + align:start position:0% +shouldn't be surprised my Gap here is + + + align:start position:0% +shouldn't be surprised my Gap here is +nine so I didn't get exactly the right + + align:start position:0% +nine so I didn't get exactly the right + + + align:start position:0% +nine so I didn't get exactly the right +answer but I'm pretty close + + align:start position:0% + + + + align:start position:0% + +here now as n + + align:start position:0% + + + + align:start position:0% + +grows what happens to the gap between + + align:start position:0% +grows what happens to the gap between + + + align:start position:0% +grows what happens to the gap between +the upper bound and the lower + + align:start position:0% +the upper bound and the lower + + + align:start position:0% +the upper bound and the lower +bound what does it do it gets bigger so + + align:start position:0% +bound what does it do it gets bigger so + + + align:start position:0% +bound what does it do it gets bigger so +my Gap gets bigger that's not so nice + + align:start position:0% +my Gap gets bigger that's not so nice + + + align:start position:0% +my Gap gets bigger that's not so nice +doesn't always stay nine forever + + align:start position:0% +doesn't always stay nine forever + + + align:start position:0% +doesn't always stay nine forever +but somehow though this is still pretty + + align:start position:0% +but somehow though this is still pretty + + + align:start position:0% +but somehow though this is still pretty +good + + align:start position:0% +good + + + align:start position:0% +good +because the Gap grows but the Gap only + + align:start position:0% +because the Gap grows but the Gap only + + + align:start position:0% +because the Gap grows but the Gap only +grows as square root of + + align:start position:0% +grows as square root of + + + align:start position:0% +grows as square root of +n where the answer the bounds are + + align:start position:0% +n where the answer the bounds are + + + align:start position:0% +n where the answer the bounds are +growing as end of the three + + align:start position:0% +growing as end of the three + + + align:start position:0% +growing as end of the three +halves in other words my + + align:start position:0% +halves in other words my + + + align:start position:0% +halves in other words my +error is somewhere around here and that + + align:start position:0% +error is somewhere around here and that + + + align:start position:0% +error is somewhere around here and that +gets smaller compared to my answer which + + align:start position:0% +gets smaller compared to my answer which + + + align:start position:0% +gets smaller compared to my answer which +is somewhere around + + align:start position:0% +is somewhere around + + + align:start position:0% +is somewhere around +there all right and 's a special + + align:start position:0% +there all right and 's a special + + + align:start position:0% +there all right and 's a special +notation that people + + align:start position:0% +notation that people + + + align:start position:0% +notation that people +use fact + + align:start position:0% +use fact + + + align:start position:0% +use fact +let's let's write that down and then do + + align:start position:0% +let's let's write that down and then do + + + align:start position:0% +let's let's write that down and then do +the + + align:start position:0% + + + + align:start position:0% + +notation another way of writing this is + + align:start position:0% +notation another way of writing this is + + + align:start position:0% +notation another way of writing this is +that + + align:start position:0% +that + + + align:start position:0% +that +the the + + align:start position:0% +the the + + + align:start position:0% +the the +sum I = 1 to n ofun of I + + align:start position:0% +sum I = 1 to n ofun of I + + + align:start position:0% +sum I = 1 to n ofun of I +the leading term here is 2/3 and the + + align:start position:0% +the leading term here is 2/3 and the + + + align:start position:0% +the leading term here is 2/3 and the +three + + align:start position:0% + + + + align:start position:0% + +Hales and then there's some error term + + align:start position:0% +Hales and then there's some error term + + + align:start position:0% +Hales and then there's some error term +Delta term here call that Delta + + align:start position:0% +Delta term here call that Delta + + + align:start position:0% +Delta term here call that Delta +n and we know + + align:start position:0% + + + + align:start position:0% + +that the error term is at least a + + align:start position:0% +that the error term is at least a + + + align:start position:0% +that the error term is at least a +third and at most Ro of n minus + + align:start position:0% +third and at most Ro of n minus + + + align:start position:0% +third and at most Ro of n minus +2/3 all + + align:start position:0% +2/3 all + + + align:start position:0% +2/3 all +right so this Delta term is bounded by + + align:start position:0% +right so this Delta term is bounded by + + + align:start position:0% +right so this Delta term is bounded by +square root of n that's getting bigger + + align:start position:0% +square root of n that's getting bigger + + + align:start position:0% +square root of n that's getting bigger +as n gets big but this value compared to + + align:start position:0% +as n gets big but this value compared to + + + align:start position:0% +as n gets big but this value compared to +your answer is getting + + align:start position:0% +your answer is getting + + + align:start position:0% +your answer is getting +small that's nice and so the way that + + align:start position:0% +small that's nice and so the way that + + + align:start position:0% +small that's nice and so the way that +gets + + align:start position:0% +gets + + + align:start position:0% +gets +represented is as follows we would say + + align:start position:0% +represented is as follows we would say + + + align:start position:0% +represented is as follows we would say +it's using the Tilda + + align:start position:0% +it's using the Tilda + + + align:start position:0% +it's using the Tilda +notation we write + + align:start position:0% +notation we write + + + align:start position:0% +notation we write +Tilda 2/3 time n the 3es and now we've + + align:start position:0% +Tilda 2/3 time n the 3es and now we've + + + align:start position:0% +Tilda 2/3 time n the 3es and now we've +gotten rid of the Delta because this + + align:start position:0% +gotten rid of the Delta because this + + + align:start position:0% +gotten rid of the Delta because this +Tilda is telling us that everything else + + align:start position:0% +Tilda is telling us that everything else + + + align:start position:0% +Tilda is telling us that everything else +out here gets small compared to this as + + align:start position:0% +out here gets small compared to this as + + + align:start position:0% +out here gets small compared to this as +n gets big and the formal definition let + + align:start position:0% +n gets big and the formal definition let + + + align:start position:0% +n gets big and the formal definition let +write out the formal definition for + + align:start position:0% + + + + align:start position:0% + +it now a lot of times you you'll see + + align:start position:0% +it now a lot of times you you'll see + + + align:start position:0% +it now a lot of times you you'll see +people use this symbol to mean about + + align:start position:0% +people use this symbol to mean about + + + align:start position:0% +people use this symbol to mean about +that's informal when I'm using it here + + align:start position:0% +that's informal when I'm using it here + + + align:start position:0% +that's informal when I'm using it here +it's a very formal meaning + + align:start position:0% + + + + align:start position:0% + +mathematically a function G ofx is till + + align:start position:0% +mathematically a function G ofx is till + + + align:start position:0% +mathematically a function G ofx is till +a function h + + align:start position:0% + + + + align:start position:0% + +ofx means that the + + align:start position:0% +ofx means that the + + + align:start position:0% +ofx means that the +limit as X goes to + + align:start position:0% +limit as X goes to + + + align:start position:0% +limit as X goes to +Infinity of + + align:start position:0% +Infinity of + + + align:start position:0% +Infinity of +G over + + align:start position:0% +G over + + + align:start position:0% +G over +H is one + + align:start position:0% +H is one + + + align:start position:0% +H is one +in other words that as X goes to + + align:start position:0% +in other words that as X goes to + + + align:start position:0% +in other words that as X goes to +Infinity as X gets big the ratio of + + align:start position:0% +Infinity as X gets big the ratio of + + + align:start position:0% +Infinity as X gets big the ratio of +these guys becomes + + align:start position:0% +these guys becomes + + + align:start position:0% +these guys becomes +one all right and let's see if that's + + align:start position:0% +one all right and let's see if that's + + + align:start position:0% +one all right and let's see if that's +true + + align:start position:0% +true + + + align:start position:0% +true +here all right + + align:start position:0% +here all right + + + align:start position:0% +here all right +well square root of I equals this so I + + align:start position:0% +well square root of I equals this so I + + + align:start position:0% +well square root of I equals this so I +need to show the limit of this over that + + align:start position:0% +need to show the limit of this over that + + + align:start position:0% +need to show the limit of this over that +is one so let's check + + align:start position:0% +is one so let's check + + + align:start position:0% +is one so let's check +that limit as n goes to + + align:start position:0% +that limit as n goes to + + + align:start position:0% +that limit as n goes to +Infinity of 2/3 n 3 + + align:start position:0% +Infinity of 2/3 n 3 + + + align:start position:0% +Infinity of 2/3 n 3 +plus that Delta term over 2/3 n the + + align:start position:0% +plus that Delta term over 2/3 n the + + + align:start position:0% +plus that Delta term over 2/3 n the +3es well that + + align:start position:0% +3es well that + + + align:start position:0% +3es well that +equals divide out by 2/3 and the three + + align:start position:0% +equals divide out by 2/3 and the three + + + align:start position:0% +equals divide out by 2/3 and the three +Hales I get a + + align:start position:0% + + + + align:start position:0% + +one uh did I should I have subtracted no + + align:start position:0% +one uh did I should I have subtracted no + + + align:start position:0% +one uh did I should I have subtracted no +that's + + align:start position:0% +that's + + + align:start position:0% +that's +okay + + align:start position:0% +okay + + + align:start position:0% +okay +1+ Delta n/ 2/3 n the 3 + + align:start position:0% +1+ Delta n/ 2/3 n the 3 + + + align:start position:0% +1+ Delta n/ 2/3 n the 3 +I can pull the one out front that's 1 + + align:start position:0% +I can pull the one out front that's 1 + + + align:start position:0% +I can pull the one out front that's 1 +plus the + + align:start position:0% +plus the + + + align:start position:0% +plus the +limit and this is now Delta n is at most + + align:start position:0% +limit and this is now Delta n is at most + + + align:start position:0% +limit and this is now Delta n is at most +sare root of n so I getun of n over 2/3 + + align:start position:0% +sare root of n so I getun of n over 2/3 + + + align:start position:0% +sare root of n so I getun of n over 2/3 +n + + align:start position:0% +n + + + align:start position:0% +n +3es square root of n Over N the 3 halves + + align:start position:0% +3es square root of n Over N the 3 halves + + + align:start position:0% +3es square root of n Over N the 3 halves +that goes to + + align:start position:0% +that goes to + + + align:start position:0% +that goes to +zero so this equals + + align:start position:0% + + + + align:start position:0% + +one all right so this limit is one and + + align:start position:0% +one all right so this limit is one and + + + align:start position:0% +one all right so this limit is one and +so therefore I can say that the sum of + + align:start position:0% +so therefore I can say that the sum of + + + align:start position:0% +so therefore I can say that the sum of +the first n square roots is till the 2/3 + + align:start position:0% +the first n square roots is till the 2/3 + + + align:start position:0% +the first n square roots is till the 2/3 +and the + + align:start position:0% +and the + + + align:start position:0% +and the +3es any + + align:start position:0% +3es any + + + align:start position:0% +3es any +questions about this we're going to do a + + align:start position:0% +questions about this we're going to do a + + + align:start position:0% +questions about this we're going to do a +lot of this kind of notation next time + + align:start position:0% +lot of this kind of notation next time + + + align:start position:0% +lot of this kind of notation next time +yeah and got 23 n^ 3 + + align:start position:0% +yeah and got 23 n^ 3 + + + align:start position:0% +yeah and got 23 n^ 3 +-1 why did the + + align:start position:0% +-1 why did the + + + align:start position:0% +-1 why did the +minus1 not become part of the actual + + align:start position:0% +minus1 not become part of the actual + + + align:start position:0% +minus1 not become part of the actual +solution become part of the + + align:start position:0% +solution become part of the + + + align:start position:0% +solution become part of the +Delta okay so you bought it up to here + + align:start position:0% +Delta okay so you bought it up to here + + + align:start position:0% +Delta okay so you bought it up to here +right okay so so then I plug that in to + + align:start position:0% +right okay so so then I plug that in to + + + align:start position:0% +right okay so so then I plug that in to +the integral it appears on both sides + + align:start position:0% +the integral it appears on both sides + + + align:start position:0% +the integral it appears on both sides +here and here I add the F1 here I add + + align:start position:0% +here and here I add the F1 here I add + + + align:start position:0% +here and here I add the F1 here I add +the + + align:start position:0% +the + + + align:start position:0% +the +FN and now I have the lower bound here + + align:start position:0% +FN and now I have the lower bound here + + + align:start position:0% +FN and now I have the lower bound here +and the upper bound here are you good + + align:start position:0% +and the upper bound here are you good + + + align:start position:0% +and the upper bound here are you good +with those all right now some judgment + + align:start position:0% +with those all right now some judgment + + + align:start position:0% +with those all right now some judgment +takes place and what I'm really trying + + align:start position:0% +takes place and what I'm really trying + + + align:start position:0% +takes place and what I'm really trying +to do here is figure out what are the + + align:start position:0% +to do here is figure out what are the + + + align:start position:0% +to do here is figure out what are the +important terms in these bounds as n + + align:start position:0% +important terms in these bounds as n + + + align:start position:0% +important terms in these bounds as n +gets big how big is this growing as n + + align:start position:0% +gets big how big is this growing as n + + + align:start position:0% +gets big how big is this growing as n +gets big well as n gets big the Third is + + align:start position:0% +gets big well as n gets big the Third is + + + align:start position:0% +gets big well as n gets big the Third is +not doing + + align:start position:0% +not doing + + + align:start position:0% +not doing +much as n gets big the square root of n + + align:start position:0% +much as n gets big the square root of n + + + align:start position:0% +much as n gets big the square root of n +grows but it's nothing like what's + + align:start position:0% +grows but it's nothing like what's + + + align:start position:0% +grows but it's nothing like what's +happening here if you had to describe to + + align:start position:0% +happening here if you had to describe to + + + align:start position:0% +happening here if you had to describe to +somebody what's going on in this bound + + align:start position:0% +somebody what's going on in this bound + + + align:start position:0% +somebody what's going on in this bound +would you start here or here no you'd + + align:start position:0% +would you start here or here no you'd + + + align:start position:0% +would you start here or here no you'd +start here this is the action and + + align:start position:0% +start here this is the action and + + + align:start position:0% +start here this is the action and +there's a little bit the rest is just in + + align:start position:0% +there's a little bit the rest is just in + + + align:start position:0% +there's a little bit the rest is just in +the slop in the air and so now I've used + + align:start position:0% +the slop in the air and so now I've used + + + align:start position:0% +the slop in the air and so now I've used +judgment to say the Delta is somewhere + + align:start position:0% +judgment to say the Delta is somewhere + + + align:start position:0% +judgment to say the Delta is somewhere +in this stuff here all right what's + + align:start position:0% +in this stuff here all right what's + + + align:start position:0% +in this stuff here all right what's +really happening the nice thing is they + + align:start position:0% +really happening the nice thing is they + + + align:start position:0% +really happening the nice thing is they +match the lower bound and the upper + + align:start position:0% +match the lower bound and the upper + + + align:start position:0% +match the lower bound and the upper +bound match on that term so what I do is + + align:start position:0% +bound match on that term so what I do is + + + align:start position:0% +bound match on that term so what I do is +I + + align:start position:0% +I + + + align:start position:0% +I +write it equals this term plus something + + align:start position:0% +write it equals this term plus something + + + align:start position:0% +write it equals this term plus something +that's + + align:start position:0% +that's + + + align:start position:0% +that's +smaller and in particular it's between a + + align:start position:0% +smaller and in particular it's between a + + + align:start position:0% +smaller and in particular it's between a +third and squ of n minus + + align:start position:0% +third and squ of n minus + + + align:start position:0% +third and squ of n minus +2/3 all right so what I'm trying to + + align:start position:0% +2/3 all right so what I'm trying to + + + align:start position:0% +2/3 all right so what I'm trying to +capture here is just the guts of what's + + align:start position:0% +capture here is just the guts of what's + + + align:start position:0% +capture here is just the guts of what's +happening to this function as as n grows + + align:start position:0% +happening to this function as as n grows + + + align:start position:0% +happening to this function as as n grows +and the guts of it is this it's not + + align:start position:0% +and the guts of it is this it's not + + + align:start position:0% +and the guts of it is this it's not +exactly equal 2/3 * n the three Hales + + align:start position:0% +exactly equal 2/3 * n the three Hales + + + align:start position:0% +exactly equal 2/3 * n the three Hales +but it's close and in fact if I take the + + align:start position:0% +but it's close and in fact if I take the + + + align:start position:0% +but it's close and in fact if I take the +limit of this over that that limit goes + + align:start position:0% +limit of this over that that limit goes + + + align:start position:0% +limit of this over that that limit goes +to one it's a way of saying they're + + align:start position:0% +to one it's a way of saying they're + + + align:start position:0% +to one it's a way of saying they're +approximately the same or that's called + + align:start position:0% +approximately the same or that's called + + + align:start position:0% +approximately the same or that's called +ASM totically the same and we'll talk a + + align:start position:0% +ASM totically the same and we'll talk a + + + align:start position:0% +ASM totically the same and we'll talk a +lot more about ASM totic notation next + + align:start position:0% +lot more about ASM totic notation next + + + align:start position:0% +lot more about ASM totic notation next +time we'll give you five more symbols + + align:start position:0% +time we'll give you five more symbols + + + align:start position:0% +time we'll give you five more symbols +besides Tilda uh that people + + align:start position:0% +besides Tilda uh that people + + + align:start position:0% +besides Tilda uh that people +use but all right any questions about + + align:start position:0% +use but all right any questions about + + + align:start position:0% +use but all right any questions about +maybe start with the bounds any question + + align:start position:0% +maybe start with the bounds any question + + + align:start position:0% +maybe start with the bounds any question +on the bounds that we got that's the + + align:start position:0% +on the bounds that we got that's the + + + align:start position:0% +on the bounds that we got that's the +integration method first getting the + + align:start position:0% +integration method first getting the + + + align:start position:0% +integration method first getting the +bounds you take the + + align:start position:0% +bounds you take the + + + align:start position:0% +bounds you take the +integral you add F of one for the lower + + align:start position:0% +integral you add F of one for the lower + + + align:start position:0% +integral you add F of one for the lower +bound you add F of n for the upper bound + + align:start position:0% +bound you add F of n for the upper bound + + + align:start position:0% +bound you add F of n for the upper bound +and it's in between somewhere in + + align:start position:0% + + + + align:start position:0% + +there questions + + align:start position:0% +there questions + + + align:start position:0% +there questions +there all right then we plugged it in + + align:start position:0% +there all right then we plugged it in + + + align:start position:0% +there all right then we plugged it in +and now we we look at this Tia notation + + align:start position:0% +and now we we look at this Tia notation + + + align:start position:0% +and now we we look at this Tia notation +that says well first we write it like + + align:start position:0% +that says well first we write it like + + + align:start position:0% +that says well first we write it like +this the sum is this Value Plus an error + + align:start position:0% +this the sum is this Value Plus an error + + + align:start position:0% +this the sum is this Value Plus an error +term and lo and behold that error term + + align:start position:0% +term and lo and behold that error term + + + align:start position:0% +term and lo and behold that error term +is small if I I can if I take the limit + + align:start position:0% +is small if I I can if I take the limit + + + align:start position:0% +is small if I I can if I take the limit +of the whole thing divided by the the + + align:start position:0% +of the whole thing divided by the the + + + align:start position:0% +of the whole thing divided by the the +big term I get one which means this + + align:start position:0% +big term I get one which means this + + + align:start position:0% +big term I get one which means this +thing is really not important so I write + + align:start position:0% + + + + align:start position:0% + +this questions on + + align:start position:0% +this questions on + + + align:start position:0% +this questions on +that all + + align:start position:0% +that all + + + align:start position:0% +that all +right all right there's one more case to + + align:start position:0% +right all right there's one more case to + + + align:start position:0% +right all right there's one more case to +consider and now we're going to go back + + align:start position:0% +consider and now we're going to go back + + + align:start position:0% +consider and now we're going to go back +to the integration bounds and that is + + align:start position:0% +to the integration bounds and that is + + + align:start position:0% +to the integration bounds and that is +when f is a a decreasing function and + + align:start position:0% +when f is a a decreasing function and + + + align:start position:0% +when f is a a decreasing function and +we're going to do the analysis for that + + align:start position:0% +we're going to do the analysis for that + + + align:start position:0% +we're going to do the analysis for that +and then we'll be all + + align:start position:0% + + + + align:start position:0% + +done so we're going to look at + + align:start position:0% +done so we're going to look at + + + align:start position:0% +done so we're going to look at +integration + + align:start position:0% + + + + align:start position:0% + +bounds when f is decreasing and positive + + align:start position:0% + + + + align:start position:0% + +still all right the example here might + + align:start position:0% +still all right the example here might + + + align:start position:0% +still all right the example here might +be for + + align:start position:0% + + + + align:start position:0% + +example uh the sum I = 1 to n 1 over the + + align:start position:0% +example uh the sum I = 1 to n 1 over the + + + align:start position:0% +example uh the sum I = 1 to n 1 over the +otk of + + align:start position:0% +otk of + + + align:start position:0% +otk of +I say you had to get some idea of how + + align:start position:0% +I say you had to get some idea of how + + + align:start position:0% +I say you had to get some idea of how +fast that function is growing as a + + align:start position:0% +fast that function is growing as a + + + align:start position:0% +fast that function is growing as a +function of n I'm summing the first + + align:start position:0% +function of n I'm summing the first + + + align:start position:0% +function of n I'm summing the first +n inverses of square + + align:start position:0% +n inverses of square + + + align:start position:0% +n inverses of square +roots what is what is that roughly going + + align:start position:0% +roots what is what is that roughly going + + + align:start position:0% +roots what is what is that roughly going +to be how fast does that grow as a + + align:start position:0% +to be how fast does that grow as a + + + align:start position:0% +to be how fast does that grow as a +function of + + align:start position:0% +function of + + + align:start position:0% +function of +n all right so let's do + + align:start position:0% + + + + align:start position:0% + +that and of course one/ square of I + + align:start position:0% +that and of course one/ square of I + + + align:start position:0% +that and of course one/ square of I +decreases as I gets + + align:start position:0% +decreases as I gets + + + align:start position:0% +decreases as I gets +bigger so let's do the general picture + + align:start position:0% + + + + align:start position:0% + +again see what happens so we have + + align:start position:0% +again see what happens so we have + + + align:start position:0% +again see what happens so we have +zero 1 2 + + align:start position:0% +zero 1 2 + + + align:start position:0% +zero 1 2 +3 nus 2 N minus one n + + align:start position:0% +3 nus 2 N minus one n + + + align:start position:0% +3 nus 2 N minus one n +and now F of n is the small + + align:start position:0% +and now F of n is the small + + + align:start position:0% +and now F of n is the small +term and F of n minus + + align:start position:0% +term and F of n minus + + + align:start position:0% +term and F of n minus +one F of three + + align:start position:0% + + + + align:start position:0% + +here F of + + align:start position:0% +here F of + + + align:start position:0% +here F of +one now I'm going to draw the rectangle + + align:start position:0% +one now I'm going to draw the rectangle + + + align:start position:0% +one now I'm going to draw the rectangle +this has area F of + + align:start position:0% +this has area F of + + + align:start position:0% +this has area F of +one this one has area F of + + align:start position:0% + + + + align:start position:0% + +two this one one has area F of + + align:start position:0% + + + + align:start position:0% + +three and then this one has area F of n + + align:start position:0% +three and then this one has area F of n + + + align:start position:0% +three and then this one has area F of n +minus one + + align:start position:0% + + + + align:start position:0% + +here and then lastly area F + + align:start position:0% + + + + align:start position:0% + +ofn so the sum is the area in the + + align:start position:0% +ofn so the sum is the area in the + + + align:start position:0% +ofn so the sum is the area in the +rectangles just like before except now + + align:start position:0% +rectangles just like before except now + + + align:start position:0% +rectangles just like before except now +the rectangles are getting + + align:start position:0% +the rectangles are getting + + + align:start position:0% +the rectangles are getting +smaller let's draw the + + align:start position:0% +smaller let's draw the + + + align:start position:0% +smaller let's draw the +integral like we did before + + align:start position:0% + + + + align:start position:0% + +the integral is the area under this + + align:start position:0% +the integral is the area under this + + + align:start position:0% +the integral is the area under this +curve F ofx here just like + + align:start position:0% +curve F ofx here just like + + + align:start position:0% +curve F ofx here just like +before so this is f + + align:start position:0% +before so this is f + + + align:start position:0% +before so this is f +ofx only it's + + align:start position:0% + + + + align:start position:0% + +decreasing now let's take the area under + + align:start position:0% +decreasing now let's take the area under + + + align:start position:0% +decreasing now let's take the area under +this + + align:start position:0% + + + + align:start position:0% + +curve and add F of one to + + align:start position:0% +curve and add F of one to + + + align:start position:0% +curve and add F of one to +it if I take the area under this curve + + align:start position:0% +it if I take the area under this curve + + + align:start position:0% +it if I take the area under this curve +all the way down to here + + align:start position:0% +all the way down to here + + + align:start position:0% +all the way down to here +here and then add F of one what do I + + align:start position:0% + + + + align:start position:0% + +get upper bound on my + + align:start position:0% +get upper bound on my + + + align:start position:0% +get upper bound on my +sum okay so the sum IAL 1 to n f of I is + + align:start position:0% +sum okay so the sum IAL 1 to n f of I is + + + align:start position:0% +sum okay so the sum IAL 1 to n f of I is +upper bounded + + align:start position:0% +upper bounded + + + align:start position:0% +upper bounded +by that guy which is f of + + align:start position:0% +by that guy which is f of + + + align:start position:0% +by that guy which is f of +one plus my + + align:start position:0% + + + + align:start position:0% + +integral which is the area under the + + align:start position:0% +integral which is the area under the + + + align:start position:0% +integral which is the area under the +curve the integral is the area under + + align:start position:0% +curve the integral is the area under + + + align:start position:0% +curve the integral is the area under +that curve starting here and that in + + align:start position:0% +that curve starting here and that in + + + align:start position:0% +that curve starting here and that in +contains all these + + align:start position:0% +contains all these + + + align:start position:0% +contains all these +rectangles and then I just add in F of + + align:start position:0% +rectangles and then I just add in F of + + + align:start position:0% +rectangles and then I just add in F of +one to get an upper + + align:start position:0% +one to get an upper + + + align:start position:0% +one to get an upper +bound all right now for the lower bound + + align:start position:0% +bound all right now for the lower bound + + + align:start position:0% +bound all right now for the lower bound +think about Shifting the whole curve + + align:start position:0% +think about Shifting the whole curve + + + align:start position:0% +think about Shifting the whole curve +left by one that goes to there this goes + + align:start position:0% +left by one that goes to there this goes + + + align:start position:0% +left by one that goes to there this goes +to here that goes to here that goes to + + align:start position:0% +to here that goes to here that goes to + + + align:start position:0% +to here that goes to here that goes to +there and that goes to there + + align:start position:0% +there and that goes to there + + + align:start position:0% +there and that goes to there +the area under the curve did not change + + align:start position:0% +the area under the curve did not change + + + align:start position:0% +the area under the curve did not change +when I shifted it left by + + align:start position:0% +when I shifted it left by + + + align:start position:0% +when I shifted it left by +one this is now my area under the + + align:start position:0% +one this is now my area under the + + + align:start position:0% +one this is now my area under the +curve stops + + align:start position:0% +curve stops + + + align:start position:0% +curve stops +here what do I get when I take that area + + align:start position:0% +here what do I get when I take that area + + + align:start position:0% +here what do I get when I take that area +and add in this last box F of + + align:start position:0% + + + + align:start position:0% + +n a lower bound right because it's + + align:start position:0% +n a lower bound right because it's + + + align:start position:0% +n a lower bound right because it's +contained in all the rectangles + + align:start position:0% + + + + align:start position:0% + +now what's really + + align:start position:0% +now what's really + + + align:start position:0% +now what's really +weird about these + + align:start position:0% +weird about these + + + align:start position:0% +weird about these +formulas do they look + + align:start position:0% + + + + align:start position:0% + +familiar yeah yeah I switched them yeah + + align:start position:0% +familiar yeah yeah I switched them yeah + + + align:start position:0% +familiar yeah yeah I switched them yeah +they're the same formulas we had over + + align:start position:0% +they're the same formulas we had over + + + align:start position:0% +they're the same formulas we had over +here except we switch the direction on + + align:start position:0% +here except we switch the direction on + + + align:start position:0% +here except we switch the direction on +the less than and greater than + + align:start position:0% +the less than and greater than + + + align:start position:0% +the less than and greater than +signs or I swapped F of one and F of n + + align:start position:0% +signs or I swapped F of one and F of n + + + align:start position:0% +signs or I swapped F of one and F of n +however you want to think about it the + + align:start position:0% +however you want to think about it the + + + align:start position:0% +however you want to think about it the +lower bound here in that case became the + + align:start position:0% +lower bound here in that case became the + + + align:start position:0% +lower bound here in that case became the +upper Bound in this + + align:start position:0% +upper Bound in this + + + align:start position:0% +upper Bound in this +case I mean is that possible that the + + align:start position:0% +case I mean is that possible that the + + + align:start position:0% +case I mean is that possible that the +lower bound became the upper + + align:start position:0% +lower bound became the upper + + + align:start position:0% +lower bound became the upper +bound yeah that's yeah because what + + align:start position:0% +bound yeah that's yeah because what + + + align:start position:0% +bound yeah that's yeah because what +really happened here which is the big + + align:start position:0% +really happened here which is the big + + + align:start position:0% +really happened here which is the big +term in this case FN or F1 F1 is the big + + align:start position:0% +term in this case FN or F1 F1 is the big + + + align:start position:0% +term in this case FN or F1 F1 is the big +term because it's decreasing so it's + + align:start position:0% +term because it's decreasing so it's + + + align:start position:0% +term because it's decreasing so it's +totally symmetric all right the proof + + align:start position:0% +totally symmetric all right the proof + + + align:start position:0% +totally symmetric all right the proof +was very similar so the nice thing is + + align:start position:0% +was very similar so the nice thing is + + + align:start position:0% +was very similar so the nice thing is +you only got to remember the bounds are + + align:start position:0% +you only got to remember the bounds are + + + align:start position:0% +you only got to remember the bounds are +now simple for any sum as long as + + align:start position:0% +now simple for any sum as long as + + + align:start position:0% +now simple for any sum as long as +increasing or decreasing it's the same + + align:start position:0% +increasing or decreasing it's the same + + + align:start position:0% +increasing or decreasing it's the same +as the integral the lower bound is the + + align:start position:0% +as the integral the lower bound is the + + + align:start position:0% +as the integral the lower bound is the +smaller of the first and last term and + + align:start position:0% +smaller of the first and last term and + + + align:start position:0% +smaller of the first and last term and +the upper bounds are larger of the first + + align:start position:0% +the upper bounds are larger of the first + + + align:start position:0% +the upper bounds are larger of the first +and last term very easy to remember + + align:start position:0% +and last term very easy to remember + + + align:start position:0% +and last term very easy to remember +probably don't even need the crib sheet + + align:start position:0% +probably don't even need the crib sheet + + + align:start position:0% +probably don't even need the crib sheet +for it although to be + + align:start position:0% +for it although to be + + + align:start position:0% +for it although to be +safe want to write that + + align:start position:0% + + + + align:start position:0% + +down so now it's easy to compute good + + align:start position:0% +down so now it's easy to compute good + + + align:start position:0% +down so now it's easy to compute good +bounds on the sum of the inverse square + + align:start position:0% +bounds on the sum of the inverse square + + + align:start position:0% +bounds on the sum of the inverse square +roots + + align:start position:0% + + + + align:start position:0% + +any questions there before I + + align:start position:0% +any questions there before I + + + align:start position:0% +any questions there before I +go do it okay so let's take the case + + align:start position:0% +go do it okay so let's take the case + + + align:start position:0% +go do it okay so let's take the case +where we're summing 1 over < TK + + align:start position:0% + + + + align:start position:0% + +I so we compute the + + align:start position:0% +I so we compute the + + + align:start position:0% +I so we compute the +integral of 1 overun of X + + align:start position:0% +integral of 1 overun of X + + + align:start position:0% +integral of 1 overun of X +DX that equals theun of X over a half + + align:start position:0% +DX that equals theun of X over a half + + + align:start position:0% +DX that equals theun of X over a half +evaluated at n and + + align:start position:0% +evaluated at n and + + + align:start position:0% +evaluated at n and +1 that equals 2 < TK + + align:start position:0% +1 that equals 2 < TK + + + align:start position:0% +1 that equals 2 < TK +nus1 or 2un of + + align:start position:0% +nus1 or 2un of + + + align:start position:0% +nus1 or 2un of +nus + + align:start position:0% +nus + + + align:start position:0% +nus +2 and now we can bound the + + align:start position:0% + + + + align:start position:0% + +sum the upper bound is f of one plus the + + align:start position:0% +sum the upper bound is f of one plus the + + + align:start position:0% +sum the upper bound is f of one plus the +integral the lower bound + + align:start position:0% +integral the lower bound + + + align:start position:0% +integral the lower bound +is f of n plus the + + align:start position:0% + + + + align:start position:0% + +integral what is f of + + align:start position:0% + + + + align:start position:0% + +one one one over theun of one is one + + align:start position:0% +one one one over theun of one is one + + + align:start position:0% +one one one over theun of one is one +what is f of + + align:start position:0% + + + + align:start position:0% + +n one over the root of n + + align:start position:0% +n one over the root of n + + + align:start position:0% +n one over the root of n +small all right so these bounds are + + align:start position:0% +small all right so these bounds are + + + align:start position:0% +small all right so these bounds are +pretty close here right in fact this + + align:start position:0% +pretty close here right in fact this + + + align:start position:0% +pretty close here right in fact this +gets really tiny as then gets big so I'm + + align:start position:0% +gets really tiny as then gets big so I'm + + + align:start position:0% +gets really tiny as then gets big so I'm +just going to replace this with 2un n 2 + + align:start position:0% +just going to replace this with 2un n 2 + + + align:start position:0% +just going to replace this with 2un n 2 +and make it a strict lower bound and + + align:start position:0% +and make it a strict lower bound and + + + align:start position:0% +and make it a strict lower bound and +this cancel there I get 2un nus + + align:start position:0% +this cancel there I get 2un nus + + + align:start position:0% +this cancel there I get 2un nus +1 wow these bounds are great they're + + align:start position:0% +1 wow these bounds are great they're + + + align:start position:0% +1 wow these bounds are great they're +within one for all + + align:start position:0% +within one for all + + + align:start position:0% +within one for all +in that's really + + align:start position:0% +in that's really + + + align:start position:0% +in that's really +good okay so we can rewrite this in + + align:start position:0% +good okay so we can rewrite this in + + + align:start position:0% +good okay so we can rewrite this in +terms of the what really matters what + + align:start position:0% +terms of the what really matters what + + + align:start position:0% +terms of the what really matters what +what really matters in these + + align:start position:0% +what really matters in these + + + align:start position:0% +what really matters in these +bounds what's the how fast is this + + align:start position:0% +bounds what's the how fast is this + + + align:start position:0% +bounds what's the how fast is this +function growing two 2un n that's what + + align:start position:0% +function growing two 2un n that's what + + + align:start position:0% +function growing two 2un n that's what +really matters so let's write that + + align:start position:0% + + + + align:start position:0% + +down all right so this says that the sum + + align:start position:0% +down all right so this says that the sum + + + align:start position:0% +down all right so this says that the sum +I = 1 to n of 1 over < TK + + align:start position:0% +I = 1 to n of 1 over < TK + + + align:start position:0% +I = 1 to n of 1 over < TK +I equals 2 < TK of n have a minus Delta + + align:start position:0% +I equals 2 < TK of n have a minus Delta + + + align:start position:0% +I equals 2 < TK of n have a minus Delta +n where Delta is + + align:start position:0% +n where Delta is + + + align:start position:0% +n where Delta is +between one and two + + align:start position:0% +between one and two + + + align:start position:0% +between one and two +and so if I use the Tia + + align:start position:0% + + + + align:start position:0% + +notation what would I write down here + + align:start position:0% +notation what would I write down here + + + align:start position:0% +notation what would I write down here +for the Tilda pass the + + align:start position:0% +for the Tilda pass the + + + align:start position:0% +for the Tilda pass the +Tilda I don't want to mess I don't want + + align:start position:0% +Tilda I don't want to mess I don't want + + + align:start position:0% +Tilda I don't want to mess I don't want +to keep all the Delta Stuff n gets big + + align:start position:0% +to keep all the Delta Stuff n gets big + + + align:start position:0% +to keep all the Delta Stuff n gets big +2ot n 2un + + align:start position:0% +2ot n 2un + + + align:start position:0% +2ot n 2un +n + + align:start position:0% +n + + + align:start position:0% +n +because this term over that goes to zero + + align:start position:0% +because this term over that goes to zero + + + align:start position:0% +because this term over that goes to zero +as then gets large so let's just check + + align:start position:0% +as then gets large so let's just check + + + align:start position:0% +as then gets large so let's just check +that + + align:start position:0% + + + + align:start position:0% + +so we take the limit as n goes to + + align:start position:0% +so we take the limit as n goes to + + + align:start position:0% +so we take the limit as n goes to +Infinity of 2un n minus Delta + + align:start position:0% +Infinity of 2un n minus Delta + + + align:start position:0% +Infinity of 2un n minus Delta +n Over 2un N just checking the + + align:start position:0% +n Over 2un N just checking the + + + align:start position:0% +n Over 2un N just checking the +definition now that's what the + + align:start position:0% +definition now that's what the + + + align:start position:0% +definition now that's what the +definition would + + align:start position:0% +definition would + + + align:start position:0% +definition would +be equals + + align:start position:0% +be equals + + + align:start position:0% +be equals +1 minus the + + align:start position:0% +1 minus the + + + align:start position:0% +1 minus the +limit as n goes to Infinity of 2 over + + align:start position:0% +limit as n goes to Infinity of 2 over + + + align:start position:0% +limit as n goes to Infinity of 2 over +2un n this is zero so it equals one + + align:start position:0% +2un n this is zero so it equals one + + + align:start position:0% +2un n this is zero so it equals one +and so now you know that the sum of the + + align:start position:0% +and so now you know that the sum of the + + + align:start position:0% +and so now you know that the sum of the +first n inverse square roots grows as + + align:start position:0% +first n inverse square roots grows as + + + align:start position:0% +first n inverse square roots grows as +2un n which is the integral yeah dropped + + align:start position:0% +2un n which is the integral yeah dropped + + + align:start position:0% +2un n which is the integral yeah dropped +off the lower bound that F of n was 1ot + + align:start position:0% +off the lower bound that F of n was 1ot + + + align:start position:0% +off the lower bound that F of n was 1ot +n yeah I dropped it off because it was + + align:start position:0% +n yeah I dropped it off because it was + + + align:start position:0% +n yeah I dropped it off because it was +so tiny and going to zero and just made + + align:start position:0% +so tiny and going to zero and just made + + + align:start position:0% +so tiny and going to zero and just made +a strict less than in fact yeah so I + + align:start position:0% +a strict less than in fact yeah so I + + + align:start position:0% +a strict less than in fact yeah so I +don't hurt myself by dropping it off in + + align:start position:0% +don't hurt myself by dropping it off in + + + align:start position:0% +don't hurt myself by dropping it off in +fact the lower bound was a little bit I + + align:start position:0% +fact the lower bound was a little bit I + + + align:start position:0% +fact the lower bound was a little bit I +made a little weaker lower bound so this + + align:start position:0% +made a little weaker lower bound so this + + + align:start position:0% +made a little weaker lower bound so this +is still true I just it wasn't as tight + + align:start position:0% +is still true I just it wasn't as tight + + + align:start position:0% +is still true I just it wasn't as tight +as it used to be so I could keep I could + + align:start position:0% +as it used to be so I could keep I could + + + align:start position:0% +as it used to be so I could keep I could +keep it + + align:start position:0% +keep it + + + align:start position:0% +keep it +around yeah it doesn't hurt to keep it + + align:start position:0% +around yeah it doesn't hurt to keep it + + + align:start position:0% +around yeah it doesn't hurt to keep it +around then it's a less than or equal + + align:start position:0% +around then it's a less than or equal + + + align:start position:0% +around then it's a less than or equal +there um and now this would + + align:start position:0% +there um and now this would + + + align:start position:0% +there um and now this would +be + + align:start position:0% + + + + align:start position:0% + +uh something like that so I could keep + + align:start position:0% +uh something like that so I could keep + + + align:start position:0% +uh something like that so I could keep +it around but I'm going to get rid of it + + align:start position:0% +it around but I'm going to get rid of it + + + align:start position:0% +it around but I'm going to get rid of it +anyway because I'm going to go to the + + align:start position:0% +anyway because I'm going to go to the + + + align:start position:0% +anyway because I'm going to go to the +Tilted + + align:start position:0% +Tilted + + + align:start position:0% +Tilted +notation and this as then gets big this + + align:start position:0% +notation and this as then gets big this + + + align:start position:0% +notation and this as then gets big this +is really tiny so in this case the + + align:start position:0% +is really tiny so in this case the + + + align:start position:0% +is really tiny so in this case the +bounds are great they're you can nail it + + align:start position:0% +bounds are great they're you can nail it + + + align:start position:0% +bounds are great they're you can nail it +pretty much right on + + align:start position:0% + + + + align:start position:0% + +yeah one there the number is bigger than + + align:start position:0% +yeah one there the number is bigger than + + + align:start position:0% +yeah one there the number is bigger than +would be so we need take it out it + + align:start position:0% +would be so we need take it out it + + + align:start position:0% +would be so we need take it out it +becomes smaller so how could you go + + align:start position:0% +becomes smaller so how could you go + + + align:start position:0% +becomes smaller so how could you go +to well you're saying you don't like the + + align:start position:0% +to well you're saying you don't like the + + + align:start position:0% +to well you're saying you don't like the +fact that dropped it here yes like when + + align:start position:0% +fact that dropped it here yes like when + + + align:start position:0% +fact that dropped it here yes like when +you drop it why do you go to instead of + + align:start position:0% +you drop it why do you go to instead of + + + align:start position:0% +you drop it why do you go to instead of +oh because I've got I've got a bigger + + align:start position:0% +oh because I've got I've got a bigger + + + align:start position:0% +oh because I've got I've got a bigger +bigger bound that I made less when I + + align:start position:0% +bigger bound that I made less when I + + + align:start position:0% +bigger bound that I made less when I +dropped it I took something away so I + + align:start position:0% +dropped it I took something away so I + + + align:start position:0% +dropped it I took something away so I +know I could never equal this because I + + align:start position:0% +know I could never equal this because I + + + align:start position:0% +know I could never equal this because I +know it's bigger than + + align:start position:0% +know it's bigger than + + + align:start position:0% +know it's bigger than +this I know that the real answer has to + + align:start position:0% +this I know that the real answer has to + + + align:start position:0% +this I know that the real answer has to +be at least this big and so it has to be + + align:start position:0% +be at least this big and so it has to be + + + align:start position:0% +be at least this big and so it has to be +bigger than something smaller that's why + + align:start position:0% +bigger than something smaller that's why + + + align:start position:0% +bigger than something smaller that's why +I did + + align:start position:0% + + + + align:start position:0% + +it okay any other + + align:start position:0% +it okay any other + + + align:start position:0% +it okay any other +questions all right we'll get more + + align:start position:0% +questions all right we'll get more + + + align:start position:0% +questions all right we'll get more +practice tomorrow and next time with + + align:start position:0% +practice tomorrow and next time with + + + align:start position:0% +practice tomorrow and next time with +this stuff \ No newline at end of file diff --git a/feEXMWBQGZk.txt b/feEXMWBQGZk.txt new file mode 100644 index 0000000000000000000000000000000000000000..7567dda5e0a78d2eafb4d75f368094df44a3762e --- /dev/null +++ b/feEXMWBQGZk.txt @@ -0,0 +1,1779 @@ +align:start position:0% + +in this video let us look at a basic yet + + align:start position:0% +in this video let us look at a basic yet + + + align:start position:0% +in this video let us look at a basic yet +important Concept in probability known + + align:start position:0% +important Concept in probability known + + + align:start position:0% +important Concept in probability known +as linearity of expectations and use it + + align:start position:0% +as linearity of expectations and use it + + + align:start position:0% +as linearity of expectations and use it +to deduce some interesting consequences + + align:start position:0% +to deduce some interesting consequences + + + align:start position:0% +to deduce some interesting consequences +in combinatorics via the probabilistic + + align:start position:0% +in combinatorics via the probabilistic + + + align:start position:0% +in combinatorics via the probabilistic +method linearity of expectations set + + align:start position:0% +method linearity of expectations set + + + align:start position:0% +method linearity of expectations set +that if you're given random variables X1 + + align:start position:0% +that if you're given random variables X1 + + + align:start position:0% +that if you're given random variables X1 +through XM and constants C1 through + + align:start position:0% +through XM and constants C1 through + + + align:start position:0% +through XM and constants C1 through +CM then when we took it when we take a + + align:start position:0% +CM then when we took it when we take a + + + align:start position:0% +CM then when we took it when we take a +linear combination of these random + + align:start position:0% +linear combination of these random + + + align:start position:0% +linear combination of these random +variables as such so C1 * X1 so imagine + + align:start position:0% +variables as such so C1 * X1 so imagine + + + align:start position:0% +variables as such so C1 * X1 so imagine +these are real valued random variables + + align:start position:0% +these are real valued random variables + + + align:start position:0% +these are real valued random variables +and these are real constants for + + align:start position:0% +and these are real constants for + + + align:start position:0% +and these are real constants for +instance then the sum of these uh C1 * + + align:start position:0% +instance then the sum of these uh C1 * + + + align:start position:0% +instance then the sum of these uh C1 * +X1 plus C2 * X2 and so on Plus CN * XM + + align:start position:0% +X1 plus C2 * X2 and so on Plus CN * XM + + + align:start position:0% +X1 plus C2 * X2 and so on Plus CN * XM +so this sum has + + align:start position:0% +so this sum has + + + align:start position:0% +so this sum has +expectation the following which can be + + align:start position:0% +expectation the following which can be + + + align:start position:0% +expectation the following which can be +computed by Distributing this + + align:start position:0% +computed by Distributing this + + + align:start position:0% +computed by Distributing this +expectation symbol across to the + + align:start position:0% +expectation symbol across to the + + + align:start position:0% +expectation symbol across to the +individual + + align:start position:0% +individual + + + align:start position:0% +individual +variables so this is a basic and + + align:start position:0% +variables so this is a basic and + + + align:start position:0% +variables so this is a basic and +important property and it's worth noting + + align:start position:0% +important property and it's worth noting + + + align:start position:0% +important property and it's worth noting +that a similar statement written for + + align:start position:0% +that a similar statement written for + + + align:start position:0% +that a similar statement written for +products is often not true so it is not + + align:start position:0% +products is often not true so it is not + + + align:start position:0% +products is often not true so it is not +usually the case that the expectation of + + align:start position:0% +usually the case that the expectation of + + + align:start position:0% +usually the case that the expectation of +a product of two random + + align:start position:0% +a product of two random + + + align:start position:0% +a product of two random +variables is the product of their + + align:start position:0% +variables is the product of their + + + align:start position:0% +variables is the product of their +expectations unless you're in some + + align:start position:0% +expectations unless you're in some + + + align:start position:0% +expectations unless you're in some +special circumstances such as when X and + + align:start position:0% +special circumstances such as when X and + + + align:start position:0% +special circumstances such as when X and +Y are independent or + + align:start position:0% +Y are independent or + + + align:start position:0% +Y are independent or +uncorrelated okay anyway let us focus on + + align:start position:0% +uncorrelated okay anyway let us focus on + + + align:start position:0% +uncorrelated okay anyway let us focus on +the linearity of expectations and see + + align:start position:0% +the linearity of expectations and see + + + align:start position:0% +the linearity of expectations and see +some ways to use this in combinatorial + + align:start position:0% +some ways to use this in combinatorial + + + align:start position:0% +some ways to use this in combinatorial +applications and the first example is + + align:start position:0% +applications and the first example is + + + align:start position:0% +applications and the first example is +the following question which will be + + align:start position:0% +the following question which will be + + + align:start position:0% +the following question which will be +able to give a very quick and clean + + align:start position:0% +able to give a very quick and clean + + + align:start position:0% +able to give a very quick and clean +answer the question is what is the + + align:start position:0% +answer the question is what is the + + + align:start position:0% +answer the question is what is the +average number of fixed points of a + + align:start position:0% +average number of fixed points of a + + + align:start position:0% +average number of fixed points of a +permutation of 1 through n + + align:start position:0% +permutation of 1 through n + + + align:start position:0% +permutation of 1 through n +chosen uniformly at random as a reminder + + align:start position:0% +chosen uniformly at random as a reminder + + + align:start position:0% +chosen uniformly at random as a reminder +if we + + align:start position:0% +if we + + + align:start position:0% +if we +have numbers 1 2 3 4 here n equals to 4 + + align:start position:0% +have numbers 1 2 3 4 here n equals to 4 + + + align:start position:0% +have numbers 1 2 3 4 here n equals to 4 +then a permutation can be thought as + + align:start position:0% +then a permutation can be thought as + + + align:start position:0% +then a permutation can be thought as +some way to map these numbers the sets + + align:start position:0% +some way to map these numbers the sets + + + align:start position:0% +some way to map these numbers the sets +back to themselves in one to one + + align:start position:0% +back to themselves in one to one + + + align:start position:0% +back to themselves in one to one +correspondence and a fixed + + align:start position:0% + + + + align:start position:0% + +point is some number + + align:start position:0% +point is some number + + + align:start position:0% +point is some number +that gets mapped back back to themselves + + align:start position:0% +that gets mapped back back to themselves + + + align:start position:0% +that gets mapped back back to themselves +so in this permutation there are exactly + + align:start position:0% +so in this permutation there are exactly + + + align:start position:0% +so in this permutation there are exactly +two fixed + + align:start position:0% +two fixed + + + align:start position:0% +two fixed +points okay + + align:start position:0% +points okay + + + align:start position:0% +points okay +great let's answer this question using + + align:start position:0% +great let's answer this question using + + + align:start position:0% +great let's answer this question using +linearity of + + align:start position:0% +linearity of + + + align:start position:0% +linearity of +expectations + + align:start position:0% +expectations + + + align:start position:0% +expectations +well one way to think about the problem + + align:start position:0% +well one way to think about the problem + + + align:start position:0% +well one way to think about the problem +is that well there are n factorial + + align:start position:0% +is that well there are n factorial + + + align:start position:0% +is that well there are n factorial +permutations and maybe we want to try to + + align:start position:0% +permutations and maybe we want to try to + + + align:start position:0% +permutations and maybe we want to try to +go about counting how many of them have + + align:start position:0% +go about counting how many of them have + + + align:start position:0% +go about counting how many of them have +zero fixed points how many of them have + + align:start position:0% +zero fixed points how many of them have + + + align:start position:0% +zero fixed points how many of them have +one fixed points how many have two fixed + + align:start position:0% +one fixed points how many have two fixed + + + align:start position:0% +one fixed points how many have two fixed +points but that method can get pretty + + align:start position:0% +points but that method can get pretty + + + align:start position:0% +points but that method can get pretty +cumbersome and pretty difficult quite + + align:start position:0% +cumbersome and pretty difficult quite + + + align:start position:0% +cumbersome and pretty difficult quite +quickly however if we look at this + + align:start position:0% +quickly however if we look at this + + + align:start position:0% +quickly however if we look at this +problem through the lens of linearity of + + align:start position:0% +problem through the lens of linearity of + + + align:start position:0% +problem through the lens of linearity of +expectations there turns out to be a + + align:start position:0% +expectations there turns out to be a + + + align:start position:0% +expectations there turns out to be a +very quick + + align:start position:0% +very quick + + + align:start position:0% +very quick +solution and the method is to let + + align:start position:0% +solution and the method is to let + + + align:start position:0% +solution and the method is to let +introduce some random variables let X I + + align:start position:0% +introduce some random variables let X I + + + align:start position:0% +introduce some random variables let X I +be a random variable that equals to one + + align:start position:0% +be a random variable that equals to one + + + align:start position:0% +be a random variable that equals to one +if I is a fixed + + align:start position:0% + + + + align:start position:0% + +Point meaning that in this permutation I + + align:start position:0% +Point meaning that in this permutation I + + + align:start position:0% +Point meaning that in this permutation I +gets mapped to itself and zero + + align:start position:0% + + + + align:start position:0% + +otherwise so X of I is the indicator + + align:start position:0% +otherwise so X of I is the indicator + + + align:start position:0% +otherwise so X of I is the indicator +random variable for the element I being + + align:start position:0% +random variable for the element I being + + + align:start position:0% +random variable for the element I being +a fixed point of this random + + align:start position:0% + + + + align:start position:0% + +permutation what's the expectation of XI + + align:start position:0% +permutation what's the expectation of XI + + + align:start position:0% +permutation what's the expectation of XI +well this is the + + align:start position:0% +well this is the + + + align:start position:0% +well this is the +probability that I is a fixed point + + align:start position:0% + + + + align:start position:0% + +well this being a uniform permutation + + align:start position:0% +well this being a uniform permutation + + + align:start position:0% +well this being a uniform permutation +chosen uniformly at random I is sent to + + align:start position:0% +chosen uniformly at random I is sent to + + + align:start position:0% +chosen uniformly at random I is sent to +each of the elements 1 through n with + + align:start position:0% +each of the elements 1 through n with + + + align:start position:0% +each of the elements 1 through n with +equal probabilities so in particular it + + align:start position:0% +equal probabilities so in particular it + + + align:start position:0% +equal probabilities so in particular it +is sent back to itself with probability + + align:start position:0% +is sent back to itself with probability + + + align:start position:0% +is sent back to itself with probability +1 / + + align:start position:0% +1 / + + + align:start position:0% +1 / +n and then the number of fixed + + align:start position:0% + + + + align:start position:0% + +points equals to the sum of the + + align:start position:0% + + + + align:start position:0% + +X XIs so X1 plus X2 so on to xn and now + + align:start position:0% +X XIs so X1 plus X2 so on to xn and now + + + align:start position:0% +X XIs so X1 plus X2 so on to xn and now +we can take expectation of both + + align:start position:0% + + + + align:start position:0% + +sides and apply linearity of + + align:start position:0% + + + + align:start position:0% + +expectations and see that while each + + align:start position:0% +expectations and see that while each + + + align:start position:0% +expectations and see that while each +individual term is 1 / + + align:start position:0% + + + + align:start position:0% + +n and there are n such terms so the + + align:start position:0% +n and there are n such terms so the + + + align:start position:0% +n and there are n such terms so the +answer is one and that is the answer to + + align:start position:0% +answer is one and that is the answer to + + + align:start position:0% +answer is one and that is the answer to +this question so the average number of + + align:start position:0% +this question so the average number of + + + align:start position:0% +this question so the average number of +fixed points of a permutation chosen + + align:start position:0% +fixed points of a permutation chosen + + + align:start position:0% +fixed points of a permutation chosen +uniformly at random is exactly one and + + align:start position:0% +uniformly at random is exactly one and + + + align:start position:0% +uniformly at random is exactly one and +you see that there's a very quick + + align:start position:0% +you see that there's a very quick + + + align:start position:0% +you see that there's a very quick +calculation once you get a hang of the + + align:start position:0% +calculation once you get a hang of the + + + align:start position:0% +calculation once you get a hang of the +idea of of linearity of + + align:start position:0% +idea of of linearity of + + + align:start position:0% +idea of of linearity of +expectations let us look at a slightly + + align:start position:0% +expectations let us look at a slightly + + + align:start position:0% +expectations let us look at a slightly +more interesting + + align:start position:0% +more interesting + + + align:start position:0% +more interesting +example and for this example we'll + + align:start position:0% +example and for this example we'll + + + align:start position:0% +example and for this example we'll +consider the concept of a tournament + + align:start position:0% + + + + align:start position:0% + +okay so a tournament is a concept in + + align:start position:0% +okay so a tournament is a concept in + + + align:start position:0% +okay so a tournament is a concept in +graph Theory referring + + align:start position:0% +graph Theory referring + + + align:start position:0% +graph Theory referring +to the + + align:start position:0% +to the + + + align:start position:0% +to the +following there are nend vertices think + + align:start position:0% +following there are nend vertices think + + + align:start position:0% +following there are nend vertices think +of nend players in some tournament and + + align:start position:0% +of nend players in some tournament and + + + align:start position:0% +of nend players in some tournament and +between every pair of vertices we have + + align:start position:0% +between every pair of vertices we have + + + align:start position:0% +between every pair of vertices we have +some directed Edge pointing in one of + + align:start position:0% +some directed Edge pointing in one of + + + align:start position:0% +some directed Edge pointing in one of +these two directions so every pair of + + align:start position:0% +these two directions so every pair of + + + align:start position:0% +these two directions so every pair of +vertices there's some Edge pointing to + + align:start position:0% +vertices there's some Edge pointing to + + + align:start position:0% +vertices there's some Edge pointing to +one of the two directions + + align:start position:0% + + + + align:start position:0% + +okay so that's an example of a + + align:start position:0% +okay so that's an example of a + + + align:start position:0% +okay so that's an example of a +tournament I'll need to introduce + + align:start position:0% +tournament I'll need to introduce + + + align:start position:0% +tournament I'll need to introduce +another concept which is that of a + + align:start position:0% +another concept which is that of a + + + align:start position:0% +another concept which is that of a +Hamilton + + align:start position:0% + + + + align:start position:0% + +path so a Hamilton path is a directed + + align:start position:0% +path so a Hamilton path is a directed + + + align:start position:0% +path so a Hamilton path is a directed +path meaning we travel along the + + align:start position:0% +path meaning we travel along the + + + align:start position:0% +path meaning we travel along the +directions of these ver these edges + + align:start position:0% +directions of these ver these edges + + + align:start position:0% +directions of these ver these edges +according to their directions so + + align:start position:0% +according to their directions so + + + align:start position:0% +according to their directions so +directed path that passes + + align:start position:0% + + + + align:start position:0% + +through each + + align:start position:0% +through each + + + align:start position:0% +through each +vertex so every vertex of the graph + + align:start position:0% +vertex so every vertex of the graph + + + align:start position:0% +vertex so every vertex of the graph +exactly once no more no + + align:start position:0% + + + + align:start position:0% + +less so let's see if we can find any + + align:start position:0% +less so let's see if we can find any + + + align:start position:0% +less so let's see if we can find any +hilon paths in + + align:start position:0% +hilon paths in + + + align:start position:0% +hilon paths in +this in this examp example well I see + + align:start position:0% +this in this examp example well I see + + + align:start position:0% +this in this examp example well I see +one so if we start with the middle + + align:start position:0% +one so if we start with the middle + + + align:start position:0% +one so if we start with the middle +vertex and go along this one this Edge + + align:start position:0% +vertex and go along this one this Edge + + + align:start position:0% +vertex and go along this one this Edge +then this Edge and then this Edge okay + + align:start position:0% +then this Edge and then this Edge okay + + + align:start position:0% +then this Edge and then this Edge okay +so that's a hemoton path that goes + + align:start position:0% +so that's a hemoton path that goes + + + align:start position:0% +so that's a hemoton path that goes +through all four + + align:start position:0% +through all four + + + align:start position:0% +through all four +vertices each vertex passing through it + + align:start position:0% +vertices each vertex passing through it + + + align:start position:0% +vertices each vertex passing through it +exactly once and it always traverses + + align:start position:0% +exactly once and it always traverses + + + align:start position:0% +exactly once and it always traverses +along the direction of the + + align:start position:0% + + + + align:start position:0% + +edges okay let us prove the following + + align:start position:0% + + + + align:start position:0% + +theorem for every n + + align:start position:0% + + + + align:start position:0% + +and there + + align:start position:0% + + + + align:start position:0% + +exists a + + align:start position:0% + + + + align:start position:0% + +tournament on N + + align:start position:0% + + + + align:start position:0% + +vertices + + align:start position:0% + + + + align:start position:0% + +with at least + + align:start position:0% + + + + align:start position:0% + +n factorial * 2 to the minus + + align:start position:0% +n factorial * 2 to the minus + + + align:start position:0% +n factorial * 2 to the minus +n + + + align:start position:0% +n + + + + align:start position:0% +n + +one hoton + + align:start position:0% + + + + align:start position:0% + +paths okay so in other words for every n + + align:start position:0% +paths okay so in other words for every n + + + align:start position:0% +paths okay so in other words for every n +there is some way to orient the edges of + + align:start position:0% +there is some way to orient the edges of + + + align:start position:0% +there is some way to orient the edges of +the complete graph on N vertices so that + + align:start position:0% +the complete graph on N vertices so that + + + align:start position:0% +the complete graph on N vertices so that +it has lots and lots of Hamilton paths + + align:start position:0% +it has lots and lots of Hamilton paths + + + align:start position:0% +it has lots and lots of Hamilton paths +specifically at least this many okay so + + align:start position:0% +specifically at least this many okay so + + + align:start position:0% +specifically at least this many okay so +that's a theorem that we're aiming to + + align:start position:0% + + + + align:start position:0% + +prove we will not prove this theorem by + + align:start position:0% +prove we will not prove this theorem by + + + align:start position:0% +prove we will not prove this theorem by +explicitly constructing such a + + align:start position:0% +explicitly constructing such a + + + align:start position:0% +explicitly constructing such a +tournament instead we'll invoke the + + align:start position:0% +tournament instead we'll invoke the + + + align:start position:0% +tournament instead we'll invoke the +probabilistic method and show that a + + align:start position:0% +probabilistic method and show that a + + + align:start position:0% +probabilistic method and show that a +random tournament has in expectation + + align:start position:0% +random tournament has in expectation + + + align:start position:0% +random tournament has in expectation +this + + align:start position:0% +this + + + align:start position:0% +this +property so here's the + + align:start position:0% +property so here's the + + + align:start position:0% +property so here's the +proof let's consider a random tournament + + align:start position:0% + + + + align:start position:0% + +on N + + align:start position:0% + + + + align:start position:0% + +vertices chosen uniformly at + + align:start position:0% + + + + align:start position:0% + +random one way to do this is to take a + + align:start position:0% +random one way to do this is to take a + + + align:start position:0% +random one way to do this is to take a +complete graph on n verticy and for + + align:start position:0% +complete graph on n verticy and for + + + align:start position:0% +complete graph on n verticy and for +every Edge flip a Fair coin and use that + + align:start position:0% +every Edge flip a Fair coin and use that + + + align:start position:0% +every Edge flip a Fair coin and use that +coin to decide which way the edge + + align:start position:0% +coin to decide which way the edge + + + align:start position:0% +coin to decide which way the edge +orients of the two different + + align:start position:0% + + + + align:start position:0% + +directions now let's think about the + + align:start position:0% +directions now let's think about the + + + align:start position:0% +directions now let's think about the +number of Hamilton paths right so + + align:start position:0% +number of Hamilton paths right so + + + align:start position:0% +number of Hamilton paths right so +each + + align:start position:0% +each + + + align:start position:0% +each +path of the so each um + + align:start position:0% + + + + align:start position:0% + +okay so each of + + align:start position:0% + + + + align:start position:0% + +the N factorial permutations of + + align:start position:0% + + + + align:start position:0% + +vertices + + align:start position:0% +vertices + + + align:start position:0% +vertices +forms a directed + + align:start position:0% + + + + align:start position:0% + +path okay so first consider a + + align:start position:0% +path okay so first consider a + + + align:start position:0% +path okay so first consider a +permutation of vertices so for example 2 + + align:start position:0% +permutation of vertices so for example 2 + + + align:start position:0% +permutation of vertices so for example 2 +1 3 3 4 and think about what is the + + align:start position:0% +1 3 3 4 and think about what is the + + + align:start position:0% +1 3 3 4 and think about what is the +probability that the edges that go in + + align:start position:0% +probability that the edges that go in + + + align:start position:0% +probability that the edges that go in +the direction of these uh of this + + align:start position:0% +the direction of these uh of this + + + align:start position:0% +the direction of these uh of this +permutation that the edges are all + + align:start position:0% +permutation that the edges are all + + + align:start position:0% +permutation that the edges are all +oriented according to the + + align:start position:0% +oriented according to the + + + align:start position:0% +oriented according to the +permutation well we have to Flip n minus + + align:start position:0% +permutation well we have to Flip n minus + + + align:start position:0% +permutation well we have to Flip n minus +one coins and all of them have to come + + align:start position:0% +one coins and all of them have to come + + + align:start position:0% +one coins and all of them have to come +up in such a way so that the edges are + + align:start position:0% +up in such a way so that the edges are + + + align:start position:0% +up in such a way so that the edges are +pointing in the direction of this + + align:start position:0% +pointing in the direction of this + + + align:start position:0% +pointing in the direction of this +permutation in order of this permutation + + align:start position:0% +permutation in order of this permutation + + + align:start position:0% +permutation in order of this permutation +so the probability + + align:start position:0% +so the probability + + + align:start position:0% +so the probability +that this is a directed path for a for + + align:start position:0% +that this is a directed path for a for + + + align:start position:0% +that this is a directed path for a for +each of these permutations is precisely + + align:start position:0% +each of these permutations is precisely + + + align:start position:0% +each of these permutations is precisely +2 to the + + align:start position:0% +2 to the + + + align:start position:0% +2 to the +minus parenthesis n minus + + align:start position:0% +minus parenthesis n minus + + + align:start position:0% +minus parenthesis n minus +one okay and now we invoke the linearity + + align:start position:0% +one okay and now we invoke the linearity + + + align:start position:0% +one okay and now we invoke the linearity +of + + align:start position:0% +of + + + align:start position:0% +of +expectations to claim that the expected + + align:start position:0% +expectations to claim that the expected + + + align:start position:0% +expectations to claim that the expected +number of Hamilton + + align:start position:0% + + + + align:start position:0% + +paths must then be well each of the N + + align:start position:0% +paths must then be well each of the N + + + align:start position:0% +paths must then be well each of the N +factorial permutations has probability + + align:start position:0% +factorial permutations has probability + + + align:start position:0% +factorial permutations has probability +of 2 + + align:start position:0% +of 2 + + + align:start position:0% +of 2 +Theus n minus one of + + align:start position:0% +Theus n minus one of + + + align:start position:0% +Theus n minus one of +being a directed path right so this is a + + align:start position:0% +being a directed path right so this is a + + + align:start position:0% +being a directed path right so this is a +calculation that is analogous to the + + align:start position:0% +calculation that is analogous to the + + + align:start position:0% +calculation that is analogous to the +calculation that we did in the earlier + + align:start position:0% +calculation that we did in the earlier + + + align:start position:0% +calculation that we did in the earlier +part of this + + align:start position:0% +part of this + + + align:start position:0% +part of this +video this is what happens in + + align:start position:0% +video this is what happens in + + + align:start position:0% +video this is what happens in +expectation on average and + + align:start position:0% +expectation on average and + + + align:start position:0% +expectation on average and +thus there must be some instance where + + align:start position:0% +thus there must be some instance where + + + align:start position:0% +thus there must be some instance where +we can beat this average or at least be + + align:start position:0% +we can beat this average or at least be + + + align:start position:0% +we can beat this average or at least be +at least as large as this average so + + align:start position:0% +at least as large as this average so + + + align:start position:0% +at least as large as this average so +thus + + align:start position:0% +thus + + + align:start position:0% +thus +there + + align:start position:0% +there + + + align:start position:0% +there +exists a + + align:start position:0% + + + + align:start position:0% + +tournament + + align:start position:0% +tournament + + + align:start position:0% +tournament +with at + + align:start position:0% + + + + align:start position:0% + +least this + + align:start position:0% +least this + + + align:start position:0% +least this +many Hamilton + + align:start position:0% + + + + align:start position:0% + +paths okay and that concludes the proof + + align:start position:0% +paths okay and that concludes the proof + + + align:start position:0% +paths okay and that concludes the proof +of this theorem that we laid out earlier + + align:start position:0% +of this theorem that we laid out earlier + + + align:start position:0% +of this theorem that we laid out earlier +so this is an example of applying + + align:start position:0% +so this is an example of applying + + + align:start position:0% +so this is an example of applying +linearity expectations as a step in the + + align:start position:0% +linearity expectations as a step in the + + + align:start position:0% +linearity expectations as a step in the +probabilistic method to prove this nice + + align:start position:0% +probabilistic method to prove this nice + + + align:start position:0% +probabilistic method to prove this nice +and simple result that there exist + + align:start position:0% +and simple result that there exist + + + align:start position:0% +and simple result that there exist +tournaments with lots of Hamilton paths \ No newline at end of file diff --git a/gEX7MjWwocE.txt b/gEX7MjWwocE.txt new file mode 100644 index 0000000000000000000000000000000000000000..eb42afe29281313818f19486505edb7559f0110f --- /dev/null +++ b/gEX7MjWwocE.txt @@ -0,0 +1,491 @@ +align:start position:0% + +the little princess asteroid b612 is + + align:start position:0% +the little princess asteroid b612 is + + + align:start position:0% +the little princess asteroid b612 is +being orbited by a small body it has a + + align:start position:0% +being orbited by a small body it has a + + + align:start position:0% +being orbited by a small body it has a +mass m and it goes around this asteroid + + align:start position:0% +mass m and it goes around this asteroid + + + align:start position:0% +mass m and it goes around this asteroid +b612 that has a mass M one you know we + + align:start position:0% +b612 that has a mass M one you know we + + + align:start position:0% +b612 that has a mass M one you know we +should add a coordinate system we always + + align:start position:0% +should add a coordinate system we always + + + align:start position:0% +should add a coordinate system we always +know that our head goes radially outward + + align:start position:0% +know that our head goes radially outward + + + align:start position:0% +know that our head goes radially outward +and we know from the universal law of + + align:start position:0% +and we know from the universal law of + + + align:start position:0% +and we know from the universal law of +gravitation that we have mutual + + align:start position:0% +gravitation that we have mutual + + + align:start position:0% +gravitation that we have mutual +attraction between these bodies and + + align:start position:0% +attraction between these bodies and + + + align:start position:0% +attraction between these bodies and +actually that's going to point inward + + align:start position:0% +actually that's going to point inward + + + align:start position:0% +actually that's going to point inward +and because we're having orbital motion + + align:start position:0% +and because we're having orbital motion + + + align:start position:0% +and because we're having orbital motion +here so circular motion the acceleration + + align:start position:0% +here so circular motion the acceleration + + + align:start position:0% +here so circular motion the acceleration +the radial component of the acceleration + + align:start position:0% +the radial component of the acceleration + + + align:start position:0% +the radial component of the acceleration +will also point inward we need to + + align:start position:0% +will also point inward we need to + + + align:start position:0% +will also point inward we need to +consider all of that for our F equals MA + + align:start position:0% +consider all of that for our F equals MA + + + align:start position:0% +consider all of that for our F equals MA +analysis that we are going to do now + + align:start position:0% +analysis that we are going to do now + + + align:start position:0% +analysis that we are going to do now +because the little prince' + + align:start position:0% +because the little prince' + + + align:start position:0% +because the little prince' +wants to know how far this little body + + align:start position:0% +wants to know how far this little body + + + align:start position:0% +wants to know how far this little body +is away from his asteroid okay so we + + align:start position:0% +is away from his asteroid okay so we + + + align:start position:0% +is away from his asteroid okay so we +have the gravitational universal law + + align:start position:0% +have the gravitational universal law + + + align:start position:0% +have the gravitational universal law +here minus G m1 over the distance + + align:start position:0% +here minus G m1 over the distance + + + align:start position:0% +here minus G m1 over the distance +squared so the distance here between the + + align:start position:0% +squared so the distance here between the + + + align:start position:0% +squared so the distance here between the +two planets R which is what we want to + + align:start position:0% +two planets R which is what we want to + + + align:start position:0% +two planets R which is what we want to +calculate and then we have over here for + + align:start position:0% +calculate and then we have over here for + + + align:start position:0% +calculate and then we have over here for +circular motion the description of M + + align:start position:0% +circular motion the description of M + + + align:start position:0% +circular motion the description of M +Omega squared now the little prince' + + align:start position:0% +Omega squared now the little prince' + + + align:start position:0% +Omega squared now the little prince' +can't measure omega but the little + + align:start position:0% +can't measure omega but the little + + + align:start position:0% +can't measure omega but the little +prince has a little time clock so what + + align:start position:0% +prince has a little time clock so what + + + align:start position:0% +prince has a little time clock so what +he can measure is the period from here + + align:start position:0% +he can measure is the period from here + + + align:start position:0% +he can measure is the period from here +until he sees the body again and that is + + align:start position:0% +until he sees the body again and that is + + + align:start position:0% +until he sees the body again and that is +2 PI over Omega so we can add that in + + align:start position:0% +2 PI over Omega so we can add that in + + + align:start position:0% +2 PI over Omega so we can add that in +here M R 4 PI squared over T squared and + + align:start position:0% +here M R 4 PI squared over T squared and + + + align:start position:0% +here M R 4 PI squared over T squared and +well there this M here will cancel out + + align:start position:0% +well there this M here will cancel out + + + align:start position:0% +well there this M here will cancel out +and now we have to solve this for R what + + align:start position:0% +and now we have to solve this for R what + + + align:start position:0% +and now we have to solve this for R what +we're going to see oh and of course we + + align:start position:0% +we're going to see oh and of course we + + + align:start position:0% +we're going to see oh and of course we +have a minus sign here because in + + align:start position:0% +have a minus sign here because in + + + align:start position:0% +have a minus sign here because in +life of the planer of the little prince + + align:start position:0% +life of the planer of the little prince + + + align:start position:0% +life of the planer of the little prince +of course gravitational obv the + + align:start position:0% +of course gravitational obv the + + + align:start position:0% +of course gravitational obv the +acceleration is not going outwards it's + + align:start position:0% +acceleration is not going outwards it's + + + align:start position:0% +acceleration is not going outwards it's +going inward so we better give this a - + + align:start position:0% +going inward so we better give this a - + + + align:start position:0% +going inward so we better give this a - +here and here as well and we will + + align:start position:0% +here and here as well and we will + + + align:start position:0% +here and here as well and we will +actually see that that then cancels out + + align:start position:0% +actually see that that then cancels out + + + align:start position:0% +actually see that that then cancels out +against this one and we're going to + + align:start position:0% +against this one and we're going to + + + align:start position:0% +against this one and we're going to +solve this for R so we get R cubed + + align:start position:0% +solve this for R so we get R cubed + + + align:start position:0% +solve this for R so we get R cubed +actually and then we have G 1 over 4 pi + + align:start position:0% +actually and then we have G 1 over 4 pi + + + align:start position:0% +actually and then we have G 1 over 4 pi +squared and here we have a t squared and + + align:start position:0% +squared and here we have a t squared and + + + align:start position:0% +squared and here we have a t squared and +you can also just write that as G 1 4 pi + + align:start position:0% +you can also just write that as G 1 4 pi + + + align:start position:0% +you can also just write that as G 1 4 pi +squared T squared and then we have third + + align:start position:0% +squared T squared and then we have third + + + align:start position:0% +squared T squared and then we have third +root so you might have seen this + + align:start position:0% +root so you might have seen this + + + align:start position:0% +root so you might have seen this +equation here this actually Kepler's law + + align:start position:0% +equation here this actually Kepler's law + + + align:start position:0% +equation here this actually Kepler's law +it describes the motion of the planets + + align:start position:0% +it describes the motion of the planets + + + align:start position:0% +it describes the motion of the planets +around the Sun well it really only does + + align:start position:0% +around the Sun well it really only does + + + align:start position:0% +around the Sun well it really only does +it if the motions are fairly circular + + align:start position:0% +it if the motions are fairly circular + + + align:start position:0% +it if the motions are fairly circular +for elliptical orbits it is not such a + + align:start position:0% +for elliptical orbits it is not such a + + + align:start position:0% +for elliptical orbits it is not such a +good approximation + + align:start position:0% +good approximation + + + align:start position:0% +good approximation +although kepler derived it like that + + align:start position:0% +although kepler derived it like that + + + align:start position:0% +although kepler derived it like that +quite quite a while ago and that was + + align:start position:0% +quite quite a while ago and that was + + + align:start position:0% +quite quite a while ago and that was +really an astonishing result so here we + + align:start position:0% +really an astonishing result so here we + + + align:start position:0% +really an astonishing result so here we +have this again that the cube of the + + align:start position:0% +have this again that the cube of the + + + align:start position:0% +have this again that the cube of the +distance between two objects is + + align:start position:0% +distance between two objects is + + + align:start position:0% +distance between two objects is +proportional to the square of the the + + align:start position:0% +proportional to the square of the the + + + align:start position:0% +proportional to the square of the the +period of the orbiting time \ No newline at end of file diff --git a/hL2GwqBRJJA.txt b/hL2GwqBRJJA.txt new file mode 100644 index 0000000000000000000000000000000000000000..48d82bfa8761a52db112b07670119131848510de --- /dev/null +++ b/hL2GwqBRJJA.txt @@ -0,0 +1,2755 @@ +align:start position:0% + +Before I um pass it over to our next + + align:start position:0% +Before I um pass it over to our next + + + align:start position:0% +Before I um pass it over to our next +moderator for the amazing panel on + + align:start position:0% +moderator for the amazing panel on + + + align:start position:0% +moderator for the amazing panel on +policy, I just want to do a a brief + + align:start position:0% +policy, I just want to do a a brief + + + align:start position:0% +policy, I just want to do a a brief +moment summarizing um our first two + + align:start position:0% +moment summarizing um our first two + + + align:start position:0% +moment summarizing um our first two +sessions. Um, and I know we started with + + align:start position:0% +sessions. Um, and I know we started with + + + align:start position:0% +sessions. Um, and I know we started with +the enormity of the global challenge in + + align:start position:0% +the enormity of the global challenge in + + + align:start position:0% +the enormity of the global challenge in +front of us at from multiple + + align:start position:0% +front of us at from multiple + + + align:start position:0% +front of us at from multiple +perspectives and I thought that was a + + align:start position:0% +perspectives and I thought that was a + + + align:start position:0% +perspectives and I thought that was a +fantastic conversation and then we turn + + align:start position:0% +fantastic conversation and then we turn + + + align:start position:0% +fantastic conversation and then we turn +to people and it's easy um to skip the + + align:start position:0% +to people and it's easy um to skip the + + + align:start position:0% +to people and it's easy um to skip the +people part and uh and to not have the + + align:start position:0% +people part and uh and to not have the + + + align:start position:0% +people part and uh and to not have the +harder conversations about all the + + align:start position:0% +harder conversations about all the + + + align:start position:0% +harder conversations about all the +different stakeholders and viewpoints + + align:start position:0% +different stakeholders and viewpoints + + + align:start position:0% +different stakeholders and viewpoints +and challenges. Um, so I'm I'm glad we + + align:start position:0% +and challenges. Um, so I'm I'm glad we + + + align:start position:0% +and challenges. Um, so I'm I'm glad we +did it. And I also um felt uh the + + align:start position:0% +did it. And I also um felt uh the + + + align:start position:0% +did it. And I also um felt uh the +um + + align:start position:0% +um + + + align:start position:0% +um +I don't know, I irony isn't quite the + + align:start position:0% +I don't know, I irony isn't quite the + + + align:start position:0% +I don't know, I irony isn't quite the +right word. I'm going to misuse it, but + + align:start position:0% +right word. I'm going to misuse it, but + + + align:start position:0% +right word. I'm going to misuse it, but +I felt the um the kind of human level of + + align:start position:0% +I felt the um the kind of human level of + + + align:start position:0% +I felt the um the kind of human level of +what it is to be in a conversation about + + align:start position:0% +what it is to be in a conversation about + + + align:start position:0% +what it is to be in a conversation about +people. Um our emotions and our beliefs. + + align:start position:0% +people. Um our emotions and our beliefs. + + + align:start position:0% +people. Um our emotions and our beliefs. +um aligning them to take action is + + align:start position:0% +um aligning them to take action is + + + align:start position:0% +um aligning them to take action is +probably the largest challenge larger + + align:start position:0% +probably the largest challenge larger + + + align:start position:0% +probably the largest challenge larger +than that first panel. + + align:start position:0% +than that first panel. + + + align:start position:0% +than that first panel. +Um and to do that requires a degree of + + align:start position:0% +Um and to do that requires a degree of + + + align:start position:0% +Um and to do that requires a degree of +vulnerability and human connection. I + + align:start position:0% +vulnerability and human connection. I + + + align:start position:0% +vulnerability and human connection. I +think it was mentioned by some of the + + align:start position:0% +think it was mentioned by some of the + + + align:start position:0% +think it was mentioned by some of the +speakers that um you know + + align:start position:0% +speakers that um you know + + + align:start position:0% +speakers that um you know +heat likes to say ch change happens at + + align:start position:0% +heat likes to say ch change happens at + + + align:start position:0% +heat likes to say ch change happens at +the speed of trust. Um it is + + align:start position:0% +the speed of trust. Um it is + + + align:start position:0% +the speed of trust. Um it is +relationshipbased. And so, um, during + + align:start position:0% +relationshipbased. And so, um, during + + + align:start position:0% +relationshipbased. And so, um, during +the lunch break, uh, after that + + align:start position:0% +the lunch break, uh, after that + + + align:start position:0% +the lunch break, uh, after that +conversation about, um, utilities and + + align:start position:0% +conversation about, um, utilities and + + + align:start position:0% +conversation about, um, utilities and +the question about trust, I was, um, + + align:start position:0% +the question about trust, I was, um, + + + align:start position:0% +the question about trust, I was, um, +chatting with, um, a leader in a gas + + align:start position:0% +chatting with, um, a leader in a gas + + + align:start position:0% +chatting with, um, a leader in a gas +utility. Um, and we ended up, and I'm + + align:start position:0% +utility. Um, and we ended up, and I'm + + + align:start position:0% +utility. Um, and we ended up, and I'm +going to totally make this incredibly + + align:start position:0% +going to totally make this incredibly + + + align:start position:0% +going to totally make this incredibly +uncomfortable and call her up. Come on, + + align:start position:0% +uncomfortable and call her up. Come on, + + + align:start position:0% +uncomfortable and call her up. Come on, +Nikki. + + align:start position:0% + + + + align:start position:0% + +>> So, here's what we were talking about. + + align:start position:0% +>> So, here's what we were talking about. + + + align:start position:0% +>> So, here's what we were talking about. +We're going to just demonstrate um a + + align:start position:0% +We're going to just demonstrate um a + + + align:start position:0% +We're going to just demonstrate um a +little bit of vulnerability and trust. + + align:start position:0% +little bit of vulnerability and trust. + + + align:start position:0% +little bit of vulnerability and trust. +We ended up in a very um personal + + align:start position:0% +We ended up in a very um personal + + + align:start position:0% +We ended up in a very um personal +conversation about how to deal with + + align:start position:0% +conversation about how to deal with + + + align:start position:0% +conversation about how to deal with +waking up in the middle of the night + + align:start position:0% +waking up in the middle of the night + + + align:start position:0% +waking up in the middle of the night +with work issues + + align:start position:0% +with work issues + + + align:start position:0% +with work issues +and challenges and and you know was was + + align:start position:0% +and challenges and and you know was was + + + align:start position:0% +and challenges and and you know was was +was diet, coffee, um uh acupuncture, um + + align:start position:0% +was diet, coffee, um uh acupuncture, um + + + align:start position:0% +was diet, coffee, um uh acupuncture, um +other methods the way to cope with the + + align:start position:0% +other methods the way to cope with the + + + align:start position:0% +other methods the way to cope with the +burden and the exhaustion of trying to + + align:start position:0% +burden and the exhaustion of trying to + + + align:start position:0% +burden and the exhaustion of trying to +lead in this space. + + align:start position:0% +lead in this space. + + + align:start position:0% +lead in this space. +>> I'm just going to hand you the mic. + + align:start position:0% +>> I'm just going to hand you the mic. + + + align:start position:0% +>> I'm just going to hand you the mic. +Well, I'm sure it's a foreign issue to + + align:start position:0% +Well, I'm sure it's a foreign issue to + + + align:start position:0% +Well, I'm sure it's a foreign issue to +everybody in the room. No one ever has + + align:start position:0% +everybody in the room. No one ever has + + + align:start position:0% +everybody in the room. No one ever has +woken up in the middle of the night. Um, + + align:start position:0% +woken up in the middle of the night. Um, + + + align:start position:0% +woken up in the middle of the night. Um, +but I think where we we came out is just + + align:start position:0% +but I think where we we came out is just + + + align:start position:0% +but I think where we we came out is just +uh the enormity of it all on your + + align:start position:0% +uh the enormity of it all on your + + + align:start position:0% +uh the enormity of it all on your +shoulders and kind of goes back to what + + align:start position:0% +shoulders and kind of goes back to what + + + align:start position:0% +shoulders and kind of goes back to what +some of the panels were saying about how + + align:start position:0% +some of the panels were saying about how + + + align:start position:0% +some of the panels were saying about how +do you break that down and helpffectuate + + align:start position:0% +do you break that down and helpffectuate + + + align:start position:0% +do you break that down and helpffectuate +change where you can. Um, and then kind + + align:start position:0% +change where you can. Um, and then kind + + + align:start position:0% +change where you can. Um, and then kind +of detach really because you know you if + + align:start position:0% +of detach really because you know you if + + + align:start position:0% +of detach really because you know you if +you're working on something that you + + align:start position:0% +you're working on something that you + + + align:start position:0% +you're working on something that you +love, even if you're exhausted, it feels + + align:start position:0% +love, even if you're exhausted, it feels + + + align:start position:0% +love, even if you're exhausted, it feels +a little less weighty than if you're + + align:start position:0% +a little less weighty than if you're + + + align:start position:0% +a little less weighty than if you're +just putting the paces in, but you know, + + align:start position:0% +just putting the paces in, but you know, + + + align:start position:0% +just putting the paces in, but you know, +you don't really care. Because I'm I get + + align:start position:0% +you don't really care. Because I'm I get + + + align:start position:0% +you don't really care. Because I'm I get +asked sometimes um sometimes by people I + + align:start position:0% +asked sometimes um sometimes by people I + + + align:start position:0% +asked sometimes um sometimes by people I +love, why do you care so much? It's just + + align:start position:0% +love, why do you care so much? It's just + + + align:start position:0% +love, why do you care so much? It's just +a job. Or and I said, well, geez, if I + + align:start position:0% +a job. Or and I said, well, geez, if I + + + align:start position:0% +a job. Or and I said, well, geez, if I +went to work and I treated it as just a + + align:start position:0% +went to work and I treated it as just a + + + align:start position:0% +went to work and I treated it as just a +job, I would be really bored. Probably + + align:start position:0% +job, I would be really bored. Probably + + + align:start position:0% +job, I would be really bored. Probably +wouldn't perform as well. And and I know + + align:start position:0% +wouldn't perform as well. And and I know + + + align:start position:0% +wouldn't perform as well. And and I know +I you know not everybody's wired that + + align:start position:0% +I you know not everybody's wired that + + + align:start position:0% +I you know not everybody's wired that +way, right? And then you think, do I + + align:start position:0% +way, right? And then you think, do I + + + align:start position:0% +way, right? And then you think, do I +have this all wrong? Because then you + + align:start position:0% +have this all wrong? Because then you + + + align:start position:0% +have this all wrong? Because then you +could detach a little easier. And so I + + align:start position:0% +could detach a little easier. And so I + + + align:start position:0% +could detach a little easier. And so I +know and it's not just me. I mean, I + + align:start position:0% +know and it's not just me. I mean, I + + + align:start position:0% +know and it's not just me. I mean, I +stand here on behalf of my team, but um + + align:start position:0% +stand here on behalf of my team, but um + + + align:start position:0% +stand here on behalf of my team, but um +a lot of us are dealing with that. And + + align:start position:0% +a lot of us are dealing with that. And + + + align:start position:0% +a lot of us are dealing with that. And +and I think it's just thinking about the + + align:start position:0% +and I think it's just thinking about the + + + align:start position:0% +and I think it's just thinking about the +global picture and the to use the word + + align:start position:0% +global picture and the to use the word + + + align:start position:0% +global picture and the to use the word +enormity of it all, but what locally can + + align:start position:0% +enormity of it all, but what locally can + + + align:start position:0% +enormity of it all, but what locally can +you control and what can you do and + + align:start position:0% +you control and what can you do and + + + align:start position:0% +you control and what can you do and +trying to do the now I sound like a + + align:start position:0% +trying to do the now I sound like a + + + align:start position:0% +trying to do the now I sound like a +Frozen movie, but the next right thing I + + align:start position:0% +Frozen movie, but the next right thing I + + + align:start position:0% +Frozen movie, but the next right thing I +think was the song. You can tell how old + + align:start position:0% +think was the song. You can tell how old + + + align:start position:0% +think was the song. You can tell how old +my kids are. Yeah, + + align:start position:0% +my kids are. Yeah, + + + align:start position:0% +my kids are. Yeah, +>> I was going to say that. + + align:start position:0% +>> I was going to say that. + + + align:start position:0% +>> I was going to say that. +>> Thank you so much, Nikki, for for + + align:start position:0% +>> Thank you so much, Nikki, for for + + + align:start position:0% +>> Thank you so much, Nikki, for for +volunteering to do that. Um, and I just + + align:start position:0% +volunteering to do that. Um, and I just + + + align:start position:0% +volunteering to do that. Um, and I just +I wanted to do that to bring like that + + align:start position:0% +I wanted to do that to bring like that + + + align:start position:0% +I wanted to do that to bring like that +level of the people conversation in in + + align:start position:0% +level of the people conversation in in + + + align:start position:0% +level of the people conversation in in +response to some of the conversation we + + align:start position:0% +response to some of the conversation we + + + align:start position:0% +response to some of the conversation we +had before is just it's actually just + + align:start position:0% +had before is just it's actually just + + + align:start position:0% +had before is just it's actually just +human. And as you get to know other + + align:start position:0% +human. And as you get to know other + + + align:start position:0% +human. And as you get to know other +humans, no matter where they are in the + + align:start position:0% +humans, no matter where they are in the + + + align:start position:0% +humans, no matter where they are in the +system, you will find over and over + + align:start position:0% +system, you will find over and over + + + align:start position:0% +system, you will find over and over +again that they are just humans and that + + align:start position:0% +again that they are just humans and that + + + align:start position:0% +again that they are just humans and that +it is the systems that we must evolve + + align:start position:0% +it is the systems that we must evolve + + + align:start position:0% +it is the systems that we must evolve +and change to meet the moment. So with + + align:start position:0% +and change to meet the moment. So with + + + align:start position:0% +and change to meet the moment. So with +that note, + + align:start position:0% +that note, + + + align:start position:0% +that note, +turning it over to Andrew Eiff who is + + align:start position:0% +turning it over to Andrew Eiff who is + + + align:start position:0% +turning it over to Andrew Eiff who is +going to be our next moderator. And I'm + + align:start position:0% +going to be our next moderator. And I'm + + + align:start position:0% +going to be our next moderator. And I'm +so excited for this panel. + + align:start position:0% +so excited for this panel. + + + align:start position:0% +so excited for this panel. +>> I'm excited too. I hope you all are too. + + align:start position:0% +>> I'm excited too. I hope you all are too. + + + align:start position:0% +>> I'm excited too. I hope you all are too. +I think that's a great segue. We spent + + align:start position:0% +I think that's a great segue. We spent + + + align:start position:0% +I think that's a great segue. We spent +the morning, excuse me, talking about + + align:start position:0% +the morning, excuse me, talking about + + + align:start position:0% +the morning, excuse me, talking about +the sort of high level and talking about + + align:start position:0% +the sort of high level and talking about + + + align:start position:0% +the sort of high level and talking about +people and I think policy can seem like + + align:start position:0% +people and I think policy can seem like + + + align:start position:0% +people and I think policy can seem like +a sort of depersonified kind of a thing. + + align:start position:0% +a sort of depersonified kind of a thing. + + + align:start position:0% +a sort of depersonified kind of a thing. +It's just out there in the system, in + + align:start position:0% +It's just out there in the system, in + + + align:start position:0% +It's just out there in the system, in +the atmosphere, in the water. But I + + align:start position:0% +the atmosphere, in the water. But I + + + align:start position:0% +the atmosphere, in the water. But I +think we're going to hear in this panel + + align:start position:0% +think we're going to hear in this panel + + + align:start position:0% +think we're going to hear in this panel +about people making that policy and what + + align:start position:0% +about people making that policy and what + + + align:start position:0% +about people making that policy and what +is driving them, what are the + + align:start position:0% +is driving them, what are the + + + align:start position:0% +is driving them, what are the +opportunities, what are the challenges + + align:start position:0% +opportunities, what are the challenges + + + align:start position:0% +opportunities, what are the challenges +that they see. Uh we're going to begin + + align:start position:0% +that they see. Uh we're going to begin + + + align:start position:0% +that they see. Uh we're going to begin +with a video from Laurig Shakudian. She + + align:start position:0% +with a video from Laurig Shakudian. She + + + align:start position:0% +with a video from Laurig Shakudian. She +represents district 20 in in the + + align:start position:0% +represents district 20 in in the + + + align:start position:0% +represents district 20 in in the +Maryland assembly and serves on the + + align:start position:0% +Maryland assembly and serves on the + + + align:start position:0% +Maryland assembly and serves on the +economic matters committee. As you will + + align:start position:0% +economic matters committee. As you will + + + align:start position:0% +economic matters committee. As you will +hear, Laurig is a passionate and + + align:start position:0% +hear, Laurig is a passionate and + + + align:start position:0% +hear, Laurig is a passionate and +thoughtful advocate and also runs + + align:start position:0% +thoughtful advocate and also runs + + + align:start position:0% +thoughtful advocate and also runs +ultramarathons, which may help explain + + align:start position:0% +ultramarathons, which may help explain + + + align:start position:0% +ultramarathons, which may help explain +her stamina in pushing for geothermal + + align:start position:0% +her stamina in pushing for geothermal + + + align:start position:0% +her stamina in pushing for geothermal +networks. + + align:start position:0% +networks. + + + align:start position:0% +networks. +>> Delegate Lauren Chudian uh in the + + align:start position:0% +>> Delegate Lauren Chudian uh in the + + + align:start position:0% +>> Delegate Lauren Chudian uh in the +Maryland General Assembly and I am + + align:start position:0% +Maryland General Assembly and I am + + + align:start position:0% +Maryland General Assembly and I am +sending my greetings and a little bit of + + align:start position:0% +sending my greetings and a little bit of + + + align:start position:0% +sending my greetings and a little bit of +jealousy because I wish I was there with + + align:start position:0% +jealousy because I wish I was there with + + + align:start position:0% +jealousy because I wish I was there with +you. + + align:start position:0% +you. + + + align:start position:0% +you. +>> Um but I'm here in the Maryland General + + align:start position:0% +>> Um but I'm here in the Maryland General + + + align:start position:0% +>> Um but I'm here in the Maryland General +Assembly. We are in full session and I + + align:start position:0% +Assembly. We are in full session and I + + + align:start position:0% +Assembly. We are in full session and I +have bill hearings at the time that you + + align:start position:0% +have bill hearings at the time that you + + + align:start position:0% +have bill hearings at the time that you +all are meeting. So, I know your + + align:start position:0% +all are meeting. So, I know your + + + align:start position:0% +all are meeting. So, I know your +meetings um and your conversations are + + align:start position:0% +meetings um and your conversations are + + + align:start position:0% +meetings um and your conversations are +probably amazing and I look forward to + + align:start position:0% +probably amazing and I look forward to + + + align:start position:0% +probably amazing and I look forward to +hearing about everything that you are + + align:start position:0% +hearing about everything that you are + + + align:start position:0% +hearing about everything that you are +learning from each other as I continue + + align:start position:0% +learning from each other as I continue + + + align:start position:0% +learning from each other as I continue +to be part of this amazing network of + + align:start position:0% +to be part of this amazing network of + + + align:start position:0% +to be part of this amazing network of +people across the country uh who are + + align:start position:0% +people across the country uh who are + + + align:start position:0% +people across the country uh who are +moving legislation and pilots and + + align:start position:0% +moving legislation and pilots and + + + align:start position:0% +moving legislation and pilots and +programs forward to increase um network + + align:start position:0% +programs forward to increase um network + + + align:start position:0% +programs forward to increase um network +geothermal systems across our + + align:start position:0% +geothermal systems across our + + + align:start position:0% +geothermal systems across our +communities. Um last year around this + + align:start position:0% +communities. Um last year around this + + + align:start position:0% +communities. Um last year around this +time I was working to pass the warmth + + align:start position:0% +time I was working to pass the warmth + + + align:start position:0% +time I was working to pass the warmth +act which is the um working for + + align:start position:0% +act which is the um working for + + + align:start position:0% +act which is the um working for +accessible renewable Maryland thermal + + align:start position:0% +accessible renewable Maryland thermal + + + align:start position:0% +accessible renewable Maryland thermal +heat. A bit of a mouthful but really a + + align:start position:0% +heat. A bit of a mouthful but really a + + + align:start position:0% +heat. A bit of a mouthful but really a +brilliant name. Wouldn't you agree? Um + + align:start position:0% +brilliant name. Wouldn't you agree? Um + + + align:start position:0% +brilliant name. Wouldn't you agree? Um +and warmth like who doesn't want to be + + align:start position:0% +and warmth like who doesn't want to be + + + align:start position:0% +and warmth like who doesn't want to be +warm? And so with that as our entry, we + + align:start position:0% +warm? And so with that as our entry, we + + + align:start position:0% +warm? And so with that as our entry, we +were able to educate my colleagues on um + + align:start position:0% +were able to educate my colleagues on um + + + align:start position:0% +were able to educate my colleagues on um +network geothermal systems uh in our + + align:start position:0% +network geothermal systems uh in our + + + align:start position:0% +network geothermal systems uh in our +case utility owned systems and we passed + + align:start position:0% +case utility owned systems and we passed + + + align:start position:0% +case utility owned systems and we passed +the bill in uh 2024. And so now we've + + align:start position:0% +the bill in uh 2024. And so now we've + + + align:start position:0% +the bill in uh 2024. And so now we've +reached a point where the utilities are + + align:start position:0% +reached a point where the utilities are + + + align:start position:0% +reached a point where the utilities are +each putting in um their filings with + + align:start position:0% +each putting in um their filings with + + + align:start position:0% +each putting in um their filings with +working with the community on developing + + align:start position:0% +working with the community on developing + + + align:start position:0% +working with the community on developing +pilot locations um and things are moving + + align:start position:0% +pilot locations um and things are moving + + + align:start position:0% +pilot locations um and things are moving +forward. So I'll back up a little bit + + align:start position:0% +forward. So I'll back up a little bit + + + align:start position:0% +forward. So I'll back up a little bit +and tell you about our process. I became + + align:start position:0% +and tell you about our process. I became + + + align:start position:0% +and tell you about our process. I became +um really interested in geothermal in + + align:start position:0% +um really interested in geothermal in + + + align:start position:0% +um really interested in geothermal in +general when I was working both on + + align:start position:0% +general when I was working both on + + + align:start position:0% +general when I was working both on +building electrification a number of + + align:start position:0% +building electrification a number of + + + align:start position:0% +building electrification a number of +years ago. Working on building + + align:start position:0% +years ago. Working on building + + + align:start position:0% +years ago. Working on building +electrification and also simultaneously + + align:start position:0% +electrification and also simultaneously + + + align:start position:0% +electrification and also simultaneously +on looking at grid issues and and um + + align:start position:0% +on looking at grid issues and and um + + + align:start position:0% +on looking at grid issues and and um +grid stability and the ability of the + + align:start position:0% +grid stability and the ability of the + + + align:start position:0% +grid stability and the ability of the +grid to handle building and and um + + align:start position:0% +grid to handle building and and um + + + align:start position:0% +grid to handle building and and um +transportation electrification. And that + + align:start position:0% +transportation electrification. And that + + + align:start position:0% +transportation electrification. And that +was even before we were looking at load + + align:start position:0% +was even before we were looking at load + + + align:start position:0% +was even before we were looking at load +growth from data centers and other + + align:start position:0% +growth from data centers and other + + + align:start position:0% +growth from data centers and other +manufacturing. Um and it was clear to me + + align:start position:0% +manufacturing. Um and it was clear to me + + + align:start position:0% +manufacturing. Um and it was clear to me +that geothermal had to be part of our uh + + align:start position:0% +that geothermal had to be part of our uh + + + align:start position:0% +that geothermal had to be part of our uh +transition because of the fact that it + + align:start position:0% +transition because of the fact that it + + + align:start position:0% +transition because of the fact that it +has the ability to um to do the + + align:start position:0% +has the ability to um to do the + + + align:start position:0% +has the ability to um to do the +electrification superefficiently um and + + align:start position:0% +electrification superefficiently um and + + + align:start position:0% +electrification superefficiently um and +in a way that really minimizes impact on + + align:start position:0% +in a way that really minimizes impact on + + + align:start position:0% +in a way that really minimizes impact on +the grid and long-term as we've seen + + align:start position:0% +the grid and long-term as we've seen + + + align:start position:0% +the grid and long-term as we've seen +from the DOE studies um really saves an + + align:start position:0% +from the DOE studies um really saves an + + + align:start position:0% +from the DOE studies um really saves an +extraordinary amount of money in terms + + align:start position:0% +extraordinary amount of money in terms + + + align:start position:0% +extraordinary amount of money in terms +of uh infrastructure um and generation. + + align:start position:0% +of uh infrastructure um and generation. + + + align:start position:0% +of uh infrastructure um and generation. +So I got excited about that. I had an + + align:start position:0% +So I got excited about that. I had an + + + align:start position:0% +So I got excited about that. I had an +initial bill um in 2021 uh to create + + align:start position:0% +initial bill um in 2021 uh to create + + + align:start position:0% +initial bill um in 2021 uh to create +geothermal wrecks in the state. But as I + + align:start position:0% +geothermal wrecks in the state. But as I + + + align:start position:0% +geothermal wrecks in the state. But as I +was doing that research, I ran across + + align:start position:0% +was doing that research, I ran across + + + align:start position:0% +was doing that research, I ran across +the work that heat was doing and I + + align:start position:0% +the work that heat was doing and I + + + align:start position:0% +the work that heat was doing and I +absolutely fell in love with the model + + align:start position:0% +absolutely fell in love with the model + + + align:start position:0% +absolutely fell in love with the model +because for a few reasons. Um, one + + align:start position:0% +because for a few reasons. Um, one + + + align:start position:0% +because for a few reasons. Um, one +reason is because um, as I work on + + align:start position:0% +reason is because um, as I work on + + + align:start position:0% +reason is because um, as I work on +energy transition, one of my top + + align:start position:0% +energy transition, one of my top + + + align:start position:0% +energy transition, one of my top +priorities is to make sure that the jobs + + align:start position:0% +priorities is to make sure that the jobs + + + align:start position:0% +priorities is to make sure that the jobs +that are being created in our new energy + + align:start position:0% +that are being created in our new energy + + + align:start position:0% +that are being created in our new energy +economy are good union jobs and are + + align:start position:0% +economy are good union jobs and are + + + align:start position:0% +economy are good union jobs and are +equivalent to the jobs uh, that are + + align:start position:0% +equivalent to the jobs uh, that are + + + align:start position:0% +equivalent to the jobs uh, that are +being lost as we transition away from + + align:start position:0% +being lost as we transition away from + + + align:start position:0% +being lost as we transition away from +fossil fuels. And so network geothermal + + align:start position:0% +fossil fuels. And so network geothermal + + + align:start position:0% +fossil fuels. And so network geothermal +of course is the most perfect of those + + align:start position:0% +of course is the most perfect of those + + + align:start position:0% +of course is the most perfect of those +transitions because um literally the + + align:start position:0% +transitions because um literally the + + + align:start position:0% +transitions because um literally the +very same work working on pipes in the + + align:start position:0% +very same work working on pipes in the + + + align:start position:0% +very same work working on pipes in the +ground that could be done with gas is + + align:start position:0% +ground that could be done with gas is + + + align:start position:0% +ground that could be done with gas is +the very same work working on pipes in + + align:start position:0% +the very same work working on pipes in + + + align:start position:0% +the very same work working on pipes in +the ground that is done with never + + align:start position:0% +the ground that is done with never + + + align:start position:0% +the ground that is done with never +geothermal. So that sort of checked one + + align:start position:0% +geothermal. So that sort of checked one + + + align:start position:0% +geothermal. So that sort of checked one +of my top priority boxes. And then the + + align:start position:0% +of my top priority boxes. And then the + + + align:start position:0% +of my top priority boxes. And then the +idea of, you know, I do spend a lot of + + align:start position:0% +idea of, you know, I do spend a lot of + + + align:start position:0% +idea of, you know, I do spend a lot of +time um with legislation that the + + align:start position:0% +time um with legislation that the + + + align:start position:0% +time um with legislation that the +utilities don't like. Um and it's nice + + align:start position:0% +utilities don't like. Um and it's nice + + + align:start position:0% +utilities don't like. Um and it's nice +to work with the gas utilities and say, + + align:start position:0% +to work with the gas utilities and say, + + + align:start position:0% +to work with the gas utilities and say, +"Look, you know, like if you want a + + align:start position:0% +"Look, you know, like if you want a + + + align:start position:0% +"Look, you know, like if you want a +future, I don't have a problem with your + + align:start position:0% +future, I don't have a problem with your + + + align:start position:0% +future, I don't have a problem with your +future. I just have a problem with your + + align:start position:0% +future. I just have a problem with your + + + align:start position:0% +future. I just have a problem with your +current business model and your past + + align:start position:0% +current business model and your past + + + align:start position:0% +current business model and your past +business model of fossil gas." And so if + + align:start position:0% +business model of fossil gas." And so if + + + align:start position:0% +business model of fossil gas." And so if +you want a future, like let me help you + + align:start position:0% +you want a future, like let me help you + + + align:start position:0% +you want a future, like let me help you +have another kind of a future. and um + + align:start position:0% +have another kind of a future. and um + + + align:start position:0% +have another kind of a future. and um +really an opportunity to take um to take + + align:start position:0% +really an opportunity to take um to take + + + align:start position:0% +really an opportunity to take um to take +what it is that utilities do have, which + + align:start position:0% +what it is that utilities do have, which + + + align:start position:0% +what it is that utilities do have, which +is an ability and expertise on massive + + align:start position:0% +is an ability and expertise on massive + + + align:start position:0% +is an ability and expertise on massive +infrastructure projects and access to + + align:start position:0% +infrastructure projects and access to + + + align:start position:0% +infrastructure projects and access to +capital to do that um and a system that + + align:start position:0% +capital to do that um and a system that + + + align:start position:0% +capital to do that um and a system that +lets us spread the costs and the + + align:start position:0% +lets us spread the costs and the + + + align:start position:0% +lets us spread the costs and the +benefits across all rateayers. And so + + align:start position:0% +benefits across all rateayers. And so + + + align:start position:0% +benefits across all rateayers. And so +all of those things uh made me really + + align:start position:0% +all of those things uh made me really + + + align:start position:0% +all of those things uh made me really +excited about network geothermal. Um so + + align:start position:0% +excited about network geothermal. Um so + + + align:start position:0% +excited about network geothermal. Um so +I went up first and u met with folks at + + align:start position:0% +I went up first and u met with folks at + + + align:start position:0% +I went up first and u met with folks at +HEAT myself. Um learned a bunch of stuff + + align:start position:0% +HEAT myself. Um learned a bunch of stuff + + + align:start position:0% +HEAT myself. Um learned a bunch of stuff +um with um we brought up I went up with + + align:start position:0% +um with um we brought up I went up with + + + align:start position:0% +um with um we brought up I went up with +uh initially sorry first I went up with + + align:start position:0% +uh initially sorry first I went up with + + + align:start position:0% +uh initially sorry first I went up with +uh Washington gas uh and we took a look + + align:start position:0% +uh Washington gas uh and we took a look + + + align:start position:0% +uh Washington gas uh and we took a look +at the systems and then as I got clearer + + align:start position:0% +at the systems and then as I got clearer + + + align:start position:0% +at the systems and then as I got clearer +about the bill that I was putting + + align:start position:0% +about the bill that I was putting + + + align:start position:0% +about the bill that I was putting +together I started a process that I do + + align:start position:0% +together I started a process that I do + + + align:start position:0% +together I started a process that I do +on most of my big energy bills which is + + align:start position:0% +on most of my big energy bills which is + + + align:start position:0% +on most of my big energy bills which is +really bringing together all of the + + align:start position:0% +really bringing together all of the + + + align:start position:0% +really bringing together all of the +potential stakeholders. So, I was + + align:start position:0% +potential stakeholders. So, I was + + + align:start position:0% +potential stakeholders. So, I was +working with um I was working with the + + align:start position:0% +working with um I was working with the + + + align:start position:0% +working with um I was working with the +gas utilities. I was working with the + + align:start position:0% +gas utilities. I was working with the + + + align:start position:0% +gas utilities. I was working with the +labor unions, both the labor unions who + + align:start position:0% +labor unions, both the labor unions who + + + align:start position:0% +labor unions, both the labor unions who +represent gas workers. So, the in-house + + align:start position:0% +represent gas workers. So, the in-house + + + align:start position:0% +represent gas workers. So, the in-house +labor unions uh for Washington gas and + + align:start position:0% +labor unions uh for Washington gas and + + + align:start position:0% +labor unions uh for Washington gas and +BG and then also the building trades. Uh + + align:start position:0% +BG and then also the building trades. Uh + + + align:start position:0% +BG and then also the building trades. Uh +so, work that doesn't get done um by the + + align:start position:0% +so, work that doesn't get done um by the + + + align:start position:0% +so, work that doesn't get done um by the +in-house unions, construction work that + + align:start position:0% +in-house unions, construction work that + + + align:start position:0% +in-house unions, construction work that +gets contracted out could be done um by + + align:start position:0% +gets contracted out could be done um by + + + align:start position:0% +gets contracted out could be done um by +building trades. I was working very + + align:start position:0% +building trades. I was working very + + + align:start position:0% +building trades. I was working very +closely with uh the grassroots groups uh + + align:start position:0% +closely with uh the grassroots groups uh + + + align:start position:0% +closely with uh the grassroots groups uh +the housing justice folks, the climate + + align:start position:0% +the housing justice folks, the climate + + + align:start position:0% +the housing justice folks, the climate +justice folks who are doing really + + align:start position:0% +justice folks who are doing really + + + align:start position:0% +justice folks who are doing really +interesting organizing in my community + + align:start position:0% +interesting organizing in my community + + + align:start position:0% +interesting organizing in my community +where they're going in and measuring NO2 + + align:start position:0% +where they're going in and measuring NO2 + + + align:start position:0% +where they're going in and measuring NO2 +levels associated with gas stoves and + + align:start position:0% +levels associated with gas stoves and + + + align:start position:0% +levels associated with gas stoves and +then they're organizing tenants who are + + align:start position:0% +then they're organizing tenants who are + + + align:start position:0% +then they're organizing tenants who are +then going to their landlords and asking + + align:start position:0% +then going to their landlords and asking + + + align:start position:0% +then going to their landlords and asking +for um asking for electrification um for + + align:start position:0% +for um asking for electrification um for + + + align:start position:0% +for um asking for electrification um for +as a health and safety issue. So working + + align:start position:0% +as a health and safety issue. So working + + + align:start position:0% +as a health and safety issue. So working +with Action in Montgomery, Interfaith + + align:start position:0% +with Action in Montgomery, Interfaith + + + align:start position:0% +with Action in Montgomery, Interfaith +Power and Light, those were some of the + + align:start position:0% +Power and Light, those were some of the + + + align:start position:0% +Power and Light, those were some of the +groups doing that. grassroots housing + + align:start position:0% +groups doing that. grassroots housing + + + align:start position:0% +groups doing that. grassroots housing +justice, climate justice work, and then + + align:start position:0% +justice, climate justice work, and then + + + align:start position:0% +justice, climate justice work, and then +um also bringing into the conversation + + align:start position:0% +um also bringing into the conversation + + + align:start position:0% +um also bringing into the conversation +groups like the Maryland Energy + + align:start position:0% +groups like the Maryland Energy + + + align:start position:0% +groups like the Maryland Energy +Administration, the Public Service + + align:start position:0% +Administration, the Public Service + + + align:start position:0% +Administration, the Public Service +Commission, the Office of People's + + align:start position:0% +Commission, the Office of People's + + + align:start position:0% +Commission, the Office of People's +Council, and then of course all the + + align:start position:0% +Council, and then of course all the + + + align:start position:0% +Council, and then of course all the +climate groups um that do really good + + align:start position:0% +climate groups um that do really good + + + align:start position:0% +climate groups um that do really good +work in the state, Chesby Climate Action + + align:start position:0% +work in the state, Chesby Climate Action + + + align:start position:0% +work in the state, Chesby Climate Action +Network, League of Conservation, Vot + + align:start position:0% +Network, League of Conservation, Vot + + + align:start position:0% +Network, League of Conservation, Vot +Sierra Club, and others. And so, um I + + align:start position:0% +Sierra Club, and others. And so, um I + + + align:start position:0% +Sierra Club, and others. And so, um I +started working with all of those + + align:start position:0% +started working with all of those + + + align:start position:0% +started working with all of those +groups. And um I I um + + align:start position:0% +groups. And um I I um + + + align:start position:0% +groups. And um I I um +brought uh a group of people up to + + align:start position:0% +brought uh a group of people up to + + + align:start position:0% +brought uh a group of people up to +Massachusetts and thanks again to heat + + align:start position:0% +Massachusetts and thanks again to heat + + + align:start position:0% +Massachusetts and thanks again to heat +for hosting us. Um we had a chance to + + align:start position:0% +for hosting us. Um we had a chance to + + + align:start position:0% +for hosting us. Um we had a chance to +see um some of the test board holes. we + + align:start position:0% +see um some of the test board holes. we + + + align:start position:0% +see um some of the test board holes. we +had a chance to sort of stand there and + + align:start position:0% +had a chance to sort of stand there and + + + align:start position:0% +had a chance to sort of stand there and +look at, you know, buildings really, + + align:start position:0% +look at, you know, buildings really, + + + align:start position:0% +look at, you know, buildings really, +right? because um as AB likes to say + + align:start position:0% +right? because um as AB likes to say + + + align:start position:0% +right? because um as AB likes to say +there's not a lot to see but um but to + + align:start position:0% +there's not a lot to see but um but to + + + align:start position:0% +there's not a lot to see but um but to +be able to picture I think for folks who + + align:start position:0% +be able to picture I think for folks who + + + align:start position:0% +be able to picture I think for folks who +were there to be able to you know learn + + align:start position:0% +were there to be able to you know learn + + + align:start position:0% +were there to be able to you know learn +about what's happening but also to + + align:start position:0% +about what's happening but also to + + + align:start position:0% +about what's happening but also to +picture what kind of neighborhoods um uh + + align:start position:0% +picture what kind of neighborhoods um uh + + + align:start position:0% +picture what kind of neighborhoods um uh +this could be really effective in and um + + align:start position:0% +this could be really effective in and um + + + align:start position:0% +this could be really effective in and um +and then we continued to work + + align:start position:0% +and then we continued to work + + + align:start position:0% +and then we continued to work +collaboratively and and it was exciting + + align:start position:0% +collaboratively and and it was exciting + + + align:start position:0% +collaboratively and and it was exciting +to bring folks together who often are + + align:start position:0% +to bring folks together who often are + + + align:start position:0% +to bring folks together who often are +not working um in the same direction on + + align:start position:0% +not working um in the same direction on + + + align:start position:0% +not working um in the same direction on +the same policies um working through + + align:start position:0% +the same policies um working through + + + align:start position:0% +the same policies um working through +building trust across those groups of + + align:start position:0% +building trust across those groups of + + + align:start position:0% +building trust across those groups of +people and making sure that everybody + + align:start position:0% +people and making sure that everybody + + + align:start position:0% +people and making sure that everybody +body felt like the bill that we finally + + align:start position:0% +body felt like the bill that we finally + + + align:start position:0% +body felt like the bill that we finally +produced really um met the needs of of + + align:start position:0% +produced really um met the needs of of + + + align:start position:0% +produced really um met the needs of of +the folks who were going to be required + + align:start position:0% +the folks who were going to be required + + + align:start position:0% +the folks who were going to be required +and and necessary for implementation. + + align:start position:0% +and and necessary for implementation. + + + align:start position:0% +and and necessary for implementation. +And so, uh we had the bill last year in + + align:start position:0% +And so, uh we had the bill last year in + + + align:start position:0% +And so, uh we had the bill last year in +the 2024 session. Um and I'm happy to + + align:start position:0% +the 2024 session. Um and I'm happy to + + + align:start position:0% +the 2024 session. Um and I'm happy to +say it passed in the in the first year + + align:start position:0% +say it passed in the in the first year + + + align:start position:0% +say it passed in the in the first year +we introduced it. Um and really a lot of + + align:start position:0% +we introduced it. Um and really a lot of + + + align:start position:0% +we introduced it. Um and really a lot of +that had to do with the fact that we + + align:start position:0% +that had to do with the fact that we + + + align:start position:0% +that had to do with the fact that we +essentially had no opposition because + + align:start position:0% +essentially had no opposition because + + + align:start position:0% +essentially had no opposition because +everybody was sitting at the table. And + + align:start position:0% +everybody was sitting at the table. And + + + align:start position:0% +everybody was sitting at the table. And +in fact, when we went for our hearing, + + align:start position:0% +in fact, when we went for our hearing, + + + align:start position:0% +in fact, when we went for our hearing, +you know, I had the the climate justice + + align:start position:0% +you know, I had the the climate justice + + + align:start position:0% +you know, I had the the climate justice +groups and the gas workers union and the + + align:start position:0% +groups and the gas workers union and the + + + align:start position:0% +groups and the gas workers union and the +utility and the office of people's + + align:start position:0% +utility and the office of people's + + + align:start position:0% +utility and the office of people's +council and like that's a set of folks + + align:start position:0% +council and like that's a set of folks + + + align:start position:0% +council and like that's a set of folks +that I don't know if they've ever been + + align:start position:0% +that I don't know if they've ever been + + + align:start position:0% +that I don't know if they've ever been +on the same panel before, but I was + + align:start position:0% +on the same panel before, but I was + + + align:start position:0% +on the same panel before, but I was +telling my colleagues, I was like, just + + align:start position:0% +telling my colleagues, I was like, just + + + align:start position:0% +telling my colleagues, I was like, just +go ahead and take a picture of this um + + align:start position:0% +go ahead and take a picture of this um + + + align:start position:0% +go ahead and take a picture of this um +and then move my bill favorable because + + align:start position:0% +and then move my bill favorable because + + + align:start position:0% +and then move my bill favorable because +um obviously there was still work to be + + align:start position:0% +um obviously there was still work to be + + + align:start position:0% +um obviously there was still work to be +done and education and and so on, but + + align:start position:0% +done and education and and so on, but + + + align:start position:0% +done and education and and so on, but +most of the work really was the year and + + align:start position:0% +most of the work really was the year and + + + align:start position:0% +most of the work really was the year and +a half of building coalitions and + + align:start position:0% +a half of building coalitions and + + + align:start position:0% +a half of building coalitions and +connecting people with each and making + + align:start position:0% +connecting people with each and making + + + align:start position:0% +connecting people with each and making +sure that the language really met the + + align:start position:0% +sure that the language really met the + + + align:start position:0% +sure that the language really met the +needs of everybody involved. So that + + align:start position:0% +needs of everybody involved. So that + + + align:start position:0% +needs of everybody involved. So that +bill passed and then soon after we + + align:start position:0% +bill passed and then soon after we + + + align:start position:0% +bill passed and then soon after we +started um you know working with the gas + + align:start position:0% +started um you know working with the gas + + + align:start position:0% +started um you know working with the gas +companies uh to to start to you know + + align:start position:0% +companies uh to to start to you know + + + align:start position:0% +companies uh to to start to you know +connect them to the grassroots groups + + align:start position:0% +connect them to the grassroots groups + + + align:start position:0% +connect them to the grassroots groups +and to start to organize and identify + + align:start position:0% +and to start to organize and identify + + + align:start position:0% +and to start to organize and identify +potential locations. Um and that's + + align:start position:0% +potential locations. Um and that's + + + align:start position:0% +potential locations. Um and that's +really where we are right now. Um we're + + align:start position:0% +really where we are right now. Um we're + + + align:start position:0% +really where we are right now. Um we're +going through that process with + + align:start position:0% +going through that process with + + + align:start position:0% +going through that process with +community groups and the the gas + + align:start position:0% +community groups and the the gas + + + align:start position:0% +community groups and the the gas +companies are working on um some + + align:start position:0% +companies are working on um some + + + align:start position:0% +companies are working on um some +engineering studies and we're excited to + + align:start position:0% +engineering studies and we're excited to + + + align:start position:0% +engineering studies and we're excited to +have um to have something here in the + + align:start position:0% +have um to have something here in the + + + align:start position:0% +have um to have something here in the +next few years. So um I'll stop there. + + align:start position:0% +next few years. So um I'll stop there. + + + align:start position:0% +next few years. So um I'll stop there. +I'm not I may or may not be able to be + + align:start position:0% +I'm not I may or may not be able to be + + + align:start position:0% +I'm not I may or may not be able to be +on there for questions. I'm not sure how + + align:start position:0% +on there for questions. I'm not sure how + + + align:start position:0% +on there for questions. I'm not sure how +that's going to work, but um if anyone's + + align:start position:0% +that's going to work, but um if anyone's + + + align:start position:0% +that's going to work, but um if anyone's +interested in getting in touch with me, + + align:start position:0% +interested in getting in touch with me, + + + align:start position:0% +interested in getting in touch with me, +we'll make sure that you all have my + + align:start position:0% +we'll make sure that you all have my + + + align:start position:0% +we'll make sure that you all have my +contact information. Um so I'm happy to + + align:start position:0% +contact information. Um so I'm happy to + + + align:start position:0% +contact information. Um so I'm happy to +follow up and be supportive um as I am + + align:start position:0% +follow up and be supportive um as I am + + + align:start position:0% +follow up and be supportive um as I am +able. And I do hope to to connect with + + align:start position:0% +able. And I do hope to to connect with + + + align:start position:0% +able. And I do hope to to connect with +folks and and hear more and learn more + + align:start position:0% +folks and and hear more and learn more + + + align:start position:0% +folks and and hear more and learn more +about what you all are doing all across + + align:start position:0% +about what you all are doing all across + + + align:start position:0% +about what you all are doing all across +this country. \ No newline at end of file diff --git a/hV5af_07ToE.txt b/hV5af_07ToE.txt new file mode 100644 index 0000000000000000000000000000000000000000..d59e8e076a12fb7fb4a3f59910f33d5b01cab5b4 --- /dev/null +++ b/hV5af_07ToE.txt @@ -0,0 +1,3043 @@ +align:start position:0% + +welcome back to recitation in this video + + align:start position:0% +welcome back to recitation in this video + + + align:start position:0% +welcome back to recitation in this video +I'd like us to to work on an example of + + align:start position:0% +I'd like us to to work on an example of + + + align:start position:0% +I'd like us to to work on an example of +something you actually saw in one of the + + align:start position:0% +something you actually saw in one of the + + + align:start position:0% +something you actually saw in one of the +lecture videos and that's about + + align:start position:0% +lecture videos and that's about + + + align:start position:0% +lecture videos and that's about +reduction formulas so what I'd like us + + align:start position:0% +reduction formulas so what I'd like us + + + align:start position:0% +reduction formulas so what I'd like us +to do is to find a reduction formula for + + align:start position:0% +to do is to find a reduction formula for + + + align:start position:0% +to do is to find a reduction formula for +the integral of sin to the NX DX which + + align:start position:0% +the integral of sin to the NX DX which + + + align:start position:0% +the integral of sin to the NX DX which +I'm denoting by f subn of x that's + + align:start position:0% +I'm denoting by f subn of x that's + + + align:start position:0% +I'm denoting by f subn of x that's +actually f subn of x is it's the + + align:start position:0% +actually f subn of x is it's the + + + align:start position:0% +actually f subn of x is it's the +integral of sinx raised to the N DX so + + align:start position:0% +integral of sinx raised to the N DX so + + + align:start position:0% +integral of sinx raised to the N DX so +the object here just to remind you of + + align:start position:0% +the object here just to remind you of + + + align:start position:0% +the object here just to remind you of +what we'd like to do is to be able to + + align:start position:0% +what we'd like to do is to be able to + + + align:start position:0% +what we'd like to do is to be able to +write f subn of x in a form where maybe + + align:start position:0% +write f subn of x in a form where maybe + + + align:start position:0% +write f subn of x in a form where maybe +it involves some functions but any + + align:start position:0% +it involves some functions but any + + + align:start position:0% +it involves some functions but any +integral that it involves is an integral + + align:start position:0% +integral that it involves is an integral + + + align:start position:0% +integral that it involves is an integral +of s to a lower power than n so an + + align:start position:0% +of s to a lower power than n so an + + + align:start position:0% +of s to a lower power than n so an +integral of sin x to a lower power than + + align:start position:0% +integral of sin x to a lower power than + + + align:start position:0% +integral of sin x to a lower power than +n so that's the object the object is to + + align:start position:0% +n so that's the object the object is to + + + align:start position:0% +n so that's the object the object is to +write this down in such a way that this + + align:start position:0% +write this down in such a way that this + + + align:start position:0% +write this down in such a way that this +integral is equal to some some functions + + align:start position:0% +integral is equal to some some functions + + + align:start position:0% +integral is equal to some some functions +maybe uh product of some functions added + + align:start position:0% +maybe uh product of some functions added + + + align:start position:0% +maybe uh product of some functions added +to uh another function that's like f but + + align:start position:0% +to uh another function that's like f but + + + align:start position:0% +to uh another function that's like f but +with a lower + + align:start position:0% +with a lower + + + align:start position:0% +with a lower +subscript so I'm going to give you a + + align:start position:0% +subscript so I'm going to give you a + + + align:start position:0% +subscript so I'm going to give you a +little time to work on it why don't you + + align:start position:0% +little time to work on it why don't you + + + align:start position:0% +little time to work on it why don't you +pause the video take some time to work + + align:start position:0% +pause the video take some time to work + + + align:start position:0% +pause the video take some time to work +on it and when I come back I'll show you + + align:start position:0% +on it and when I come back I'll show you + + + align:start position:0% +on it and when I come back I'll show you +how I do + + align:start position:0% + + + + align:start position:0% + +it okay welcome back well hopefully you + + align:start position:0% +it okay welcome back well hopefully you + + + align:start position:0% +it okay welcome back well hopefully you +were able to make some Headway on this + + align:start position:0% +were able to make some Headway on this + + + align:start position:0% +were able to make some Headway on this +problem so let's take a look again at + + align:start position:0% +problem so let's take a look again at + + + align:start position:0% +problem so let's take a look again at +what we want to do what the goal is and + + align:start position:0% +what we want to do what the goal is and + + + align:start position:0% +what we want to do what the goal is and +then we'll we'll figure out a good + + align:start position:0% +then we'll we'll figure out a good + + + align:start position:0% +then we'll we'll figure out a good +strategy to do that so the goal is to be + + align:start position:0% +strategy to do that so the goal is to be + + + align:start position:0% +strategy to do that so the goal is to be +able to write f subn of x as something + + align:start position:0% +able to write f subn of x as something + + + align:start position:0% +able to write f subn of x as something +that involves a lower a lower numbered + + align:start position:0% +that involves a lower a lower numbered + + + align:start position:0% +that involves a lower a lower numbered +subscript than n right so we'd like to + + align:start position:0% +subscript than n right so we'd like to + + + align:start position:0% +subscript than n right so we'd like to +be able to take this integral that's a + + align:start position:0% +be able to take this integral that's a + + + align:start position:0% +be able to take this integral that's a +power of sinx and reduce the number of + + align:start position:0% +power of sinx and reduce the number of + + + align:start position:0% +power of sinx and reduce the number of +powers you know it'd be great if we + + align:start position:0% +powers you know it'd be great if we + + + align:start position:0% +powers you know it'd be great if we +could just write down a final formula + + align:start position:0% +could just write down a final formula + + + align:start position:0% +could just write down a final formula +but if we're able to to reduce the power + + align:start position:0% +but if we're able to to reduce the power + + + align:start position:0% +but if we're able to to reduce the power +of sinx then we're able to head in a + + align:start position:0% +of sinx then we're able to head in a + + + align:start position:0% +of sinx then we're able to head in a +Direction Where We could start to write + + align:start position:0% +Direction Where We could start to write + + + align:start position:0% +Direction Where We could start to write +down + + align:start position:0% +down + + + align:start position:0% +down +um start to write down this down as as + + align:start position:0% +um start to write down this down as as + + + align:start position:0% +um start to write down this down as as +functions that don't involve integrals + + align:start position:0% +functions that don't involve integrals + + + align:start position:0% +functions that don't involve integrals +so the the first step in these kinds of + + align:start position:0% +so the the first step in these kinds of + + + align:start position:0% +so the the first step in these kinds of +things is finding a reduction formula so + + align:start position:0% +things is finding a reduction formula so + + + align:start position:0% +things is finding a reduction formula so +a couple things I want to remind us um + + align:start position:0% +a couple things I want to remind us um + + + align:start position:0% +a couple things I want to remind us um +we're going to make the common + + align:start position:0% +we're going to make the common + + + align:start position:0% +we're going to make the common +substitution that we that we make uh for + + align:start position:0% +substitution that we that we make uh for + + + align:start position:0% +substitution that we that we make uh for +for powers of sign or powers of cosine + + align:start position:0% +for powers of sign or powers of cosine + + + align:start position:0% +for powers of sign or powers of cosine +that we see a lot um well I guess + + align:start position:0% +that we see a lot um well I guess + + + align:start position:0% +that we see a lot um well I guess +actually there's two when you just see a + + align:start position:0% +actually there's two when you just see a + + + align:start position:0% +actually there's two when you just see a +sign squared sometimes you do this this + + align:start position:0% +sign squared sometimes you do this this + + + align:start position:0% +sign squared sometimes you do this this +half angle formula or double angle + + align:start position:0% +half angle formula or double angle + + + align:start position:0% +half angle formula or double angle +formula that that Joel has mentioned in + + align:start position:0% +formula that that Joel has mentioned in + + + align:start position:0% +formula that that Joel has mentioned in +some videos but in this one we're more + + align:start position:0% +some videos but in this one we're more + + + align:start position:0% +some videos but in this one we're more +interested in uh manipulating the + + align:start position:0% + + + + align:start position:0% + +identity sin^2 X plus cosine squ x equal + + align:start position:0% +identity sin^2 X plus cosine squ x equal + + + align:start position:0% +identity sin^2 X plus cosine squ x equal +1 in particular we're going to replace + + align:start position:0% +1 in particular we're going to replace + + + align:start position:0% +1 in particular we're going to replace +one of the sin squ X's or we're going to + + align:start position:0% +one of the sin squ X's or we're going to + + + align:start position:0% +one of the sin squ X's or we're going to +replace two of the signs by 1 - cosine 2 + + align:start position:0% +replace two of the signs by 1 - cosine 2 + + + align:start position:0% +replace two of the signs by 1 - cosine 2 +x so that'll be our first step so we're + + align:start position:0% +x so that'll be our first step so we're + + + align:start position:0% +x so that'll be our first step so we're +going to do that substitution we'll + + align:start position:0% +going to do that substitution we'll + + + align:start position:0% +going to do that substitution we'll +break it into some pieces we'll see + + align:start position:0% +break it into some pieces we'll see + + + align:start position:0% +break it into some pieces we'll see +where we get okay so let me come over + + align:start position:0% +where we get okay so let me come over + + + align:start position:0% +where we get okay so let me come over +over here and I will start the problem + + align:start position:0% +over here and I will start the problem + + + align:start position:0% +over here and I will start the problem +so I'm starting with f subn of x and I'm + + align:start position:0% +so I'm starting with f subn of x and I'm + + + align:start position:0% +so I'm starting with f subn of x and I'm +going to rewrite it as the integral of + + align:start position:0% +going to rewrite it as the integral of + + + align:start position:0% +going to rewrite it as the integral of +sin to the N - 2 + + align:start position:0% +sin to the N - 2 + + + align:start position:0% +sin to the N - 2 +xan 1 - cosine 2 + + align:start position:0% +xan 1 - cosine 2 + + + align:start position:0% +xan 1 - cosine 2 +x DX so let me take a step back so what + + align:start position:0% +x DX so let me take a step back so what + + + align:start position:0% +x DX so let me take a step back so what +did we do here we took two powers of + + align:start position:0% +did we do here we took two powers of + + + align:start position:0% +did we do here we took two powers of +sign and we replace them by what I said + + align:start position:0% +sign and we replace them by what I said + + + align:start position:0% +sign and we replace them by what I said +earlier we replace them by 1us cosine 2 + + align:start position:0% +earlier we replace them by 1us cosine 2 + + + align:start position:0% +earlier we replace them by 1us cosine 2 +x right so this is a sin^2 x here I have + + align:start position:0% +x right so this is a sin^2 x here I have + + + align:start position:0% +x right so this is a sin^2 x here I have +sin x to the N minus 2 when I multiply + + align:start position:0% +sin x to the N minus 2 when I multiply + + + align:start position:0% +sin x to the N minus 2 when I multiply +those together I get sin x the N so + + align:start position:0% +those together I get sin x the N so + + + align:start position:0% +those together I get sin x the N so +everything's still working out so far + + align:start position:0% +everything's still working out so far + + + align:start position:0% +everything's still working out so far +why is this good well notice the terms + + align:start position:0% +why is this good well notice the terms + + + align:start position:0% +why is this good well notice the terms +we have sign to the nus 2 x + + align:start position:0% +we have sign to the nus 2 x + + + align:start position:0% +we have sign to the nus 2 x +DX minus the + + align:start position:0% +DX minus the + + + align:start position:0% +DX minus the +integral of sin the nus + + align:start position:0% +integral of sin the nus + + + align:start position:0% +integral of sin the nus +2x cine 2 x DX + + align:start position:0% +2x cine 2 x DX + + + align:start position:0% +2x cine 2 x DX +okay this we like why do we like this + + align:start position:0% +okay this we like why do we like this + + + align:start position:0% +okay this we like why do we like this +because it's + + align:start position:0% +because it's + + + align:start position:0% +because it's +actually just like the f subn of x + + align:start position:0% +actually just like the f subn of x + + + align:start position:0% +actually just like the f subn of x +except it has a lower power so this + + align:start position:0% +except it has a lower power so this + + + align:start position:0% +except it has a lower power so this +piece is actually f subn + + align:start position:0% +piece is actually f subn + + + align:start position:0% +piece is actually f subn +min-2 of x so that's something we like + + align:start position:0% +min-2 of x so that's something we like + + + align:start position:0% +min-2 of x so that's something we like +because it's already reduced the power + + align:start position:0% +because it's already reduced the power + + + align:start position:0% +because it's already reduced the power +of sin x by two so that's good that's + + align:start position:0% +of sin x by two so that's good that's + + + align:start position:0% +of sin x by two so that's good that's +part of the reduction idea this one + + align:start position:0% +part of the reduction idea this one + + + align:start position:0% +part of the reduction idea this one +obviously we can't write it in terms of + + align:start position:0% +obviously we can't write it in terms of + + + align:start position:0% +obviously we can't write it in terms of +capital F with some + + align:start position:0% +capital F with some + + + align:start position:0% +capital F with some +subscript and it maybe it doesn't look + + align:start position:0% +subscript and it maybe it doesn't look + + + align:start position:0% +subscript and it maybe it doesn't look +so easy to to integrate right away but + + align:start position:0% +so easy to to integrate right away but + + + align:start position:0% +so easy to to integrate right away but +let's think about it for a second how we + + align:start position:0% +let's think about it for a second how we + + + align:start position:0% +let's think about it for a second how we +could split this thing up and the goal + + align:start position:0% +could split this thing up and the goal + + + align:start position:0% +could split this thing up and the goal +is to use an integration by parts so + + align:start position:0% +is to use an integration by parts so + + + align:start position:0% +is to use an integration by parts so +we're going to examine this integral in + + align:start position:0% +we're going to examine this integral in + + + align:start position:0% +we're going to examine this integral in +particular so let me just write that one + + align:start position:0% +particular so let me just write that one + + + align:start position:0% +particular so let me just write that one +down again here so we need to analyze + + align:start position:0% +down again here so we need to analyze + + + align:start position:0% +down again here so we need to analyze +I'm going to drop the minus sign for the + + align:start position:0% +I'm going to drop the minus sign for the + + + align:start position:0% +I'm going to drop the minus sign for the +moment andus 2 + + align:start position:0% + + + + align:start position:0% + +so our goal again is to try and write + + align:start position:0% +so our goal again is to try and write + + + align:start position:0% +so our goal again is to try and write +this somehow either manipulate it so it + + align:start position:0% +this somehow either manipulate it so it + + + align:start position:0% +this somehow either manipulate it so it +looks like an a capital f function or + + align:start position:0% +looks like an a capital f function or + + + align:start position:0% +looks like an a capital f function or +manipulate it so that the the integral + + align:start position:0% +manipulate it so that the the integral + + + align:start position:0% +manipulate it so that the the integral +sign is gone okay that's our main goal + + align:start position:0% +sign is gone okay that's our main goal + + + align:start position:0% +sign is gone okay that's our main goal +here so let's look at what what we can + + align:start position:0% +here so let's look at what what we can + + + align:start position:0% +here so let's look at what what we can +do with this well I can split this up + + align:start position:0% +do with this well I can split this up + + + align:start position:0% +do with this well I can split this up +what I'm going to do it's kind of tricky + + align:start position:0% +what I'm going to do it's kind of tricky + + + align:start position:0% +what I'm going to do it's kind of tricky +but what I'm going to do is I'm going to + + align:start position:0% +but what I'm going to do is I'm going to + + + align:start position:0% +but what I'm going to do is I'm going to +take all of the S x's and I'm going to + + align:start position:0% +take all of the S x's and I'm going to + + + align:start position:0% +take all of the S x's and I'm going to +take one of the cosine + + align:start position:0% +take one of the cosine + + + align:start position:0% +take one of the cosine +x's and I'm going to make that one thing + + align:start position:0% +x's and I'm going to make that one thing + + + align:start position:0% +x's and I'm going to make that one thing +and I'm going to make the other cosine X + + align:start position:0% +and I'm going to make the other cosine X + + + align:start position:0% +and I'm going to make the other cosine X +another thing and I'm going to write + + align:start position:0% +another thing and I'm going to write + + + align:start position:0% +another thing and I'm going to write +them down first and then we'll figure + + align:start position:0% +them down first and then we'll figure + + + align:start position:0% +them down first and then we'll figure +out which is a good U and which is a + + align:start position:0% +out which is a good U and which is a + + + align:start position:0% +out which is a good U and which is a +good V + + align:start position:0% + + + + align:start position:0% + +Prime so that's going to be one thing + + align:start position:0% +Prime so that's going to be one thing + + + align:start position:0% +Prime so that's going to be one thing +and then the other cosine + + align:start position:0% +and then the other cosine + + + align:start position:0% +and then the other cosine +X it's going to be oh does that look + + align:start position:0% +X it's going to be oh does that look + + + align:start position:0% +X it's going to be oh does that look +like an equal sign equals it's going to + + align:start position:0% +like an equal sign equals it's going to + + + align:start position:0% +like an equal sign equals it's going to +be the other thing so again sin the nus + + align:start position:0% +be the other thing so again sin the nus + + + align:start position:0% +be the other thing so again sin the nus +2x * cosine x * cosine X gives me what's + + align:start position:0% +2x * cosine x * cosine X gives me what's + + + align:start position:0% +2x * cosine x * cosine X gives me what's +up here inside the integral and now what + + align:start position:0% +up here inside the integral and now what + + + align:start position:0% +up here inside the integral and now what +I really want to see I'm going to use an + + align:start position:0% +I really want to see I'm going to use an + + + align:start position:0% +I really want to see I'm going to use an +integration by parts well this is easy + + align:start position:0% +integration by parts well this is easy + + + align:start position:0% +integration by parts well this is easy +to integrate or take a derivative of but + + align:start position:0% +to integrate or take a derivative of but + + + align:start position:0% +to integrate or take a derivative of but +the point is that now I can integrate + + align:start position:0% +the point is that now I can integrate + + + align:start position:0% +the point is that now I can integrate +this and why can I integrate this well I + + align:start position:0% +this and why can I integrate this well I + + + align:start position:0% +this and why can I integrate this well I +can do a substitution on this so this is + + align:start position:0% +can do a substitution on this so this is + + + align:start position:0% +can do a substitution on this so this is +kind of complicated because there's + + align:start position:0% +kind of complicated because there's + + + align:start position:0% +kind of complicated because there's +first you have to notice an integration + + align:start position:0% +first you have to notice an integration + + + align:start position:0% +first you have to notice an integration +by parts is a good way to go with this + + align:start position:0% +by parts is a good way to go with this + + + align:start position:0% +by parts is a good way to go with this +and then you have to see oh my goodness + + align:start position:0% +and then you have to see oh my goodness + + + align:start position:0% +and then you have to see oh my goodness +this one of the steps of integration by + + align:start position:0% +this one of the steps of integration by + + + align:start position:0% +this one of the steps of integration by +parts requires substitution so it's a + + align:start position:0% +parts requires substitution so it's a + + + align:start position:0% +parts requires substitution so it's a +little tricky but I'm going to make this + + align:start position:0% +little tricky but I'm going to make this + + + align:start position:0% +little tricky but I'm going to make this +then my V + + align:start position:0% +then my V + + + align:start position:0% +then my V +Prime and I'm going to make this my + + align:start position:0% +Prime and I'm going to make this my + + + align:start position:0% +Prime and I'm going to make this my +U now I'm going to come over to the + + align:start position:0% +U now I'm going to come over to the + + + align:start position:0% +U now I'm going to come over to the +other board to figure out just to make + + align:start position:0% +other board to figure out just to make + + + align:start position:0% +other board to figure out just to make +sure I do the V Prime right okay and + + align:start position:0% +sure I do the V Prime right okay and + + + align:start position:0% +sure I do the V Prime right okay and +then I'm going to finish off this + + align:start position:0% +then I'm going to finish off this + + + align:start position:0% +then I'm going to finish off this +problem so we'll come back here in a + + align:start position:0% +problem so we'll come back here in a + + + align:start position:0% +problem so we'll come back here in a +second so right now this is a question + + align:start position:0% +second so right now this is a question + + + align:start position:0% +second so right now this is a question +mark we're going to make sure we do the + + align:start position:0% +mark we're going to make sure we do the + + + align:start position:0% +mark we're going to make sure we do the +V Prime part right and then we're going + + align:start position:0% +V Prime part right and then we're going + + + align:start position:0% +V Prime part right and then we're going +to write down this should be UV minus + + align:start position:0% +to write down this should be UV minus + + + align:start position:0% +to write down this should be UV minus +the integral of VD okay so let me give + + align:start position:0% +the integral of VD okay so let me give + + + align:start position:0% +the integral of VD okay so let me give +myself some space so I'm trying to + + align:start position:0% +myself some space so I'm trying to + + + align:start position:0% +myself some space so I'm trying to +integrate + + align:start position:0% +integrate + + + align:start position:0% +integrate +now sign the N - + + align:start position:0% +now sign the N - + + + align:start position:0% +now sign the N - +2x cosine + + align:start position:0% +2x cosine + + + align:start position:0% +2x cosine +X DX all right that's my integral of V + + align:start position:0% +X DX all right that's my integral of V + + + align:start position:0% +X DX all right that's my integral of V +Prime + + align:start position:0% +Prime + + + align:start position:0% +Prime +DX okay so this will give me V so let's + + align:start position:0% +DX okay so this will give me V so let's + + + align:start position:0% +DX okay so this will give me V so let's +see what we do we're going to now make I + + align:start position:0% +see what we do we're going to now make I + + + align:start position:0% +see what we do we're going to now make I +don't want to use a u for my + + align:start position:0% +don't want to use a u for my + + + align:start position:0% +don't want to use a u for my +substitution because I already have in + + align:start position:0% +substitution because I already have in + + + align:start position:0% +substitution because I already have in +my mind a u so I'm going to let + + align:start position:0% +my mind a u so I'm going to let + + + align:start position:0% +my mind a u so I'm going to let +W wal + + align:start position:0% +W wal + + + align:start position:0% +W wal +sinx and then DW is equal to cosin X DX + + align:start position:0% +sinx and then DW is equal to cosin X DX + + + align:start position:0% +sinx and then DW is equal to cosin X DX +right what's the what's the point here + + align:start position:0% +right what's the what's the point here + + + align:start position:0% +right what's the what's the point here +why is this do we see this as easy to + + align:start position:0% +why is this do we see this as easy to + + + align:start position:0% +why is this do we see this as easy to +integrate because this is powers of sign + + align:start position:0% +integrate because this is powers of sign + + + align:start position:0% +integrate because this is powers of sign +and the derivative of sign is cosine so + + align:start position:0% +and the derivative of sign is cosine so + + + align:start position:0% +and the derivative of sign is cosine so +that's why This lends itself to a + + align:start position:0% +that's why This lends itself to a + + + align:start position:0% +that's why This lends itself to a +substitution so easily so that should be + + align:start position:0% +substitution so easily so that should be + + + align:start position:0% +substitution so easily so that should be +fairly familiar by now but just to make + + align:start position:0% +fairly familiar by now but just to make + + + align:start position:0% +fairly familiar by now but just to make +sure we're clear so then this is now the + + align:start position:0% +sure we're clear so then this is now the + + + align:start position:0% +sure we're clear so then this is now the +integral of w to the N minus 2 + + align:start position:0% +integral of w to the N minus 2 + + + align:start position:0% +integral of w to the N minus 2 +DW right I have sin x to the nus 2 so + + align:start position:0% +DW right I have sin x to the nus 2 so + + + align:start position:0% +DW right I have sin x to the nus 2 so +that's replaced by W to the N minus 2 + + align:start position:0% +that's replaced by W to the N minus 2 + + + align:start position:0% +that's replaced by W to the N minus 2 +and then DW replaces cosin X DX X and + + align:start position:0% +and then DW replaces cosin X DX X and + + + align:start position:0% +and then DW replaces cosin X DX X and +that is pretty easy to integrate I think + + align:start position:0% +that is pretty easy to integrate I think + + + align:start position:0% +that is pretty easy to integrate I think +that's W + + align:start position:0% +that's W + + + align:start position:0% +that's W +nus1 over nus1 I'm not going to worry + + align:start position:0% +nus1 over nus1 I'm not going to worry + + + align:start position:0% +nus1 over nus1 I'm not going to worry +about my C's right now that that'll come + + align:start position:0% +about my C's right now that that'll come + + + align:start position:0% +about my C's right now that that'll come +up right at the end we'll put in a plus + + align:start position:0% +up right at the end we'll put in a plus + + + align:start position:0% +up right at the end we'll put in a plus +c if we needed to + + align:start position:0% +c if we needed to + + + align:start position:0% +c if we needed to +um but so don't worry about your plus C + + align:start position:0% +um but so don't worry about your plus C + + + align:start position:0% +um but so don't worry about your plus C +I don't want to carry that around okay + + align:start position:0% +I don't want to carry that around okay + + + align:start position:0% +I don't want to carry that around okay +so then when I when I look at this what + + align:start position:0% +so then when I when I look at this what + + + align:start position:0% +so then when I when I look at this what +does this tell me this tells me that if + + align:start position:0% +does this tell me this tells me that if + + + align:start position:0% +does this tell me this tells me that if +this was the integral of V Prime this + + align:start position:0% +this was the integral of V Prime this + + + align:start position:0% +this was the integral of V Prime this +tells me that V is equal to sinx to the + + align:start position:0% +tells me that V is equal to sinx to the + + + align:start position:0% +tells me that V is equal to sinx to the +nus1 sin the n-1 X over + + align:start position:0% +nus1 sin the n-1 X over + + + align:start position:0% +nus1 sin the n-1 X over +nus1 okay this whole bit was to help us + + align:start position:0% +nus1 okay this whole bit was to help us + + + align:start position:0% +nus1 okay this whole bit was to help us +in the middle of the problem so this was + + align:start position:0% +in the middle of the problem so this was + + + align:start position:0% +in the middle of the problem so this was +the V we needed all right so let's come + + align:start position:0% +the V we needed all right so let's come + + + align:start position:0% +the V we needed all right so let's come +back fill in a little piece we needed a + + align:start position:0% +back fill in a little piece we needed a + + + align:start position:0% +back fill in a little piece we needed a +little Gap we had and then we'll finish + + align:start position:0% +little Gap we had and then we'll finish + + + align:start position:0% +little Gap we had and then we'll finish +the problem on the far right so let's + + align:start position:0% +the problem on the far right so let's + + + align:start position:0% +the problem on the far right so let's +come back where was I okay so I was + + align:start position:0% +come back where was I okay so I was + + + align:start position:0% +come back where was I okay so I was +integrating this quantity sin the nus 2x + + align:start position:0% +integrating this quantity sin the nus 2x + + + align:start position:0% +integrating this quantity sin the nus 2x +cosine 2 x DX and I was trying to use + + align:start position:0% +cosine 2 x DX and I was trying to use + + + align:start position:0% +cosine 2 x DX and I was trying to use +integration by parts so I had u and v + + align:start position:0% +integration by parts so I had u and v + + + align:start position:0% +integration by parts so I had u and v +Prime and I've now calculated V and I + + align:start position:0% +Prime and I've now calculated V and I + + + align:start position:0% +Prime and I've now calculated V and I +know what du is so I'm going to write + + align:start position:0% +know what du is so I'm going to write + + + align:start position:0% +know what du is so I'm going to write +down what this equals this is going to + + align:start position:0% +down what this equals this is going to + + + align:start position:0% +down what this equals this is going to +be U which is cosine X and I'll just + + align:start position:0% +be U which is cosine X and I'll just + + + align:start position:0% +be U which is cosine X and I'll just +write down V here so we'll see what it + + align:start position:0% +write down V here so we'll see what it + + + align:start position:0% +write down V here so we'll see what it +is again times sin to the + + align:start position:0% +is again times sin to the + + + align:start position:0% +is again times sin to the +nus1 uh X over + + align:start position:0% +nus1 uh X over + + + align:start position:0% +nus1 uh X over +nus1 and then I have to subtract VD so + + align:start position:0% +nus1 and then I have to subtract VD so + + + align:start position:0% +nus1 and then I have to subtract VD so +this is V and what's du du is or I + + align:start position:0% +this is V and what's du du is or I + + + align:start position:0% +this is V and what's du du is or I +should say U Prime is how you saw it in + + align:start position:0% +should say U Prime is how you saw it in + + + align:start position:0% +should say U Prime is how you saw it in +class U Prime is sinx so what am I going + + align:start position:0% +class U Prime is sinx so what am I going + + + align:start position:0% +class U Prime is sinx so what am I going +to get I'm going to get sinx times the V + + align:start position:0% +to get I'm going to get sinx times the V + + + align:start position:0% +to get I'm going to get sinx times the V +that I had so when I when I subtract I'm + + align:start position:0% +that I had so when I when I subtract I'm + + + align:start position:0% +that I had so when I when I subtract I'm +going to end up with a plus sign and I'm + + align:start position:0% +going to end up with a plus sign and I'm + + + align:start position:0% +going to end up with a plus sign and I'm +going to have plus I'm going to pull out + + align:start position:0% +going to have plus I'm going to pull out + + + align:start position:0% +going to have plus I'm going to pull out +the constant 1/ n minus one integral now + + align:start position:0% +the constant 1/ n minus one integral now + + + align:start position:0% +the constant 1/ n minus one integral now +let's look at the magic that happens + + align:start position:0% +let's look at the magic that happens + + + align:start position:0% +let's look at the magic that happens +here okay let's make sure you agree with + + align:start position:0% +here okay let's make sure you agree with + + + align:start position:0% +here okay let's make sure you agree with +this power it's the nth power of sinx so + + align:start position:0% +this power it's the nth power of sinx so + + + align:start position:0% +this power it's the nth power of sinx so +let's double check + + align:start position:0% +let's double check + + + align:start position:0% +let's double check +I said U was cosine X so U Prime is Nega + + align:start position:0% +I said U was cosine X so U Prime is Nega + + + align:start position:0% +I said U was cosine X so U Prime is Nega +sinx so I have to take U Prime v u Prime + + align:start position:0% +sinx so I have to take U Prime v u Prime + + + align:start position:0% +sinx so I have to take U Prime v u Prime +is negative + + align:start position:0% +is negative + + + align:start position:0% +is negative +sinx if we come over + + align:start position:0% +sinx if we come over + + + align:start position:0% +sinx if we come over +here we see V is sinx to the N minus one + + align:start position:0% +here we see V is sinx to the N minus one + + + align:start position:0% +here we see V is sinx to the N minus one +so U Prime V is + + align:start position:0% +so U Prime V is + + + align:start position:0% +so U Prime V is +indeed uh is indeed negative uh well I + + align:start position:0% +indeed uh is indeed negative uh well I + + + align:start position:0% +indeed uh is indeed negative uh well I +should say V is sinx to the nus1 Over N + + align:start position:0% +should say V is sinx to the nus1 Over N + + + align:start position:0% +should say V is sinx to the nus1 Over N +minus1 so U Prime V in fact has the + + align:start position:0% +minus1 so U Prime V in fact has the + + + align:start position:0% +minus1 so U Prime V in fact has the +power n on sign so that's maybe a little + + align:start position:0% +power n on sign so that's maybe a little + + + align:start position:0% +power n on sign so that's maybe a little +bit complicated in nerve-wracking but + + align:start position:0% +bit complicated in nerve-wracking but + + + align:start position:0% +bit complicated in nerve-wracking but +that's that's okay we're actually headed + + align:start position:0% +that's that's okay we're actually headed + + + align:start position:0% +that's that's okay we're actually headed +in the right direction so I'm going to + + align:start position:0% +in the right direction so I'm going to + + + align:start position:0% +in the right direction so I'm going to +rewrite the stuff we know and we'll see + + align:start position:0% +rewrite the stuff we know and we'll see + + + align:start position:0% +rewrite the stuff we know and we'll see +how we're headed in the right direction + + align:start position:0% +how we're headed in the right direction + + + align:start position:0% +how we're headed in the right direction +okay so again we were trying to find f + + align:start position:0% +okay so again we were trying to find f + + + align:start position:0% +okay so again we were trying to find f +subn of x and I'm going to write out the + + align:start position:0% +subn of x and I'm going to write out the + + + align:start position:0% +subn of x and I'm going to write out the +pieces we already knew so we had an F + + align:start position:0% +pieces we already knew so we had an F + + + align:start position:0% +pieces we already knew so we had an F +subn minus 2 of X that was that was the + + align:start position:0% +subn minus 2 of X that was that was the + + + align:start position:0% +subn minus 2 of X that was that was the +first term we had and then we analyzed + + align:start position:0% +first term we had and then we analyzed + + + align:start position:0% +first term we had and then we analyzed +this second piece and the second piece + + align:start position:0% +this second piece and the second piece + + + align:start position:0% +this second piece and the second piece +is the one that we just spent a little + + align:start position:0% +is the one that we just spent a little + + + align:start position:0% +is the one that we just spent a little +while on and that gave us a cosine + + align:start position:0% +while on and that gave us a cosine + + + align:start position:0% +while on and that gave us a cosine +x s to the nus one of + + align:start position:0% +x s to the nus one of + + + align:start position:0% +x s to the nus one of +X over n + + align:start position:0% +X over n + + + align:start position:0% +X over n +minus1 and then um + + align:start position:0% +minus1 and then um + + + align:start position:0% +minus1 and then um +plus 1 over n minus one and what was our + + align:start position:0% +plus 1 over n minus one and what was our + + + align:start position:0% +plus 1 over n minus one and what was our +thing here our thing here was f subn of + + align:start position:0% +thing here our thing here was f subn of + + + align:start position:0% +thing here our thing here was f subn of +x + + align:start position:0% +x + + + align:start position:0% +x +again okay so this might be a little + + align:start position:0% +again okay so this might be a little + + + align:start position:0% +again okay so this might be a little +complicated so I'm going to I'm going to + + align:start position:0% +complicated so I'm going to I'm going to + + + align:start position:0% +complicated so I'm going to I'm going to +show us where all the pieces come from + + align:start position:0% +show us where all the pieces come from + + + align:start position:0% +show us where all the pieces come from +just to remind us so we start with f + + align:start position:0% +just to remind us so we start with f + + + align:start position:0% +just to remind us so we start with f +subn of x and I'm claiming there are two + + align:start position:0% +subn of x and I'm claiming there are two + + + align:start position:0% +subn of x and I'm claiming there are two +pieces that are of Interest okay the + + align:start position:0% +pieces that are of Interest okay the + + + align:start position:0% +pieces that are of Interest okay the +first piece let's come back + + align:start position:0% +first piece let's come back + + + align:start position:0% +first piece let's come back +over the first piece this was our f subn + + align:start position:0% +over the first piece this was our f subn + + + align:start position:0% +over the first piece this was our f subn +of x we wrote it this way the first + + align:start position:0% +of x we wrote it this way the first + + + align:start position:0% +of x we wrote it this way the first +piece was the F subn minus 2 of X sign + + align:start position:0% +piece was the F subn minus 2 of X sign + + + align:start position:0% +piece was the F subn minus 2 of X sign +the N minus 2 of x no problem then we + + align:start position:0% +the N minus 2 of x no problem then we + + + align:start position:0% +the N minus 2 of x no problem then we +subtracted this integral and so I spent + + align:start position:0% +subtracted this integral and so I spent + + + align:start position:0% +subtracted this integral and so I spent +a little while trying to figure out how + + align:start position:0% +a little while trying to figure out how + + + align:start position:0% +a little while trying to figure out how +to write that integral and that integral + + align:start position:0% +to write that integral and that integral + + + align:start position:0% +to write that integral and that integral +was written right down here so I have to + + align:start position:0% +was written right down here so I have to + + + align:start position:0% +was written right down here so I have to +subtract off all of that that and the + + align:start position:0% +subtract off all of that that and the + + + align:start position:0% +subtract off all of that that and the +point is that this integral here + + align:start position:0% +point is that this integral here + + + align:start position:0% +point is that this integral here +integral of sin x to the N the quantity + + align:start position:0% +integral of sin x to the N the quantity + + + align:start position:0% +integral of sin x to the N the quantity +of sin x to the N is f subn of x again + + align:start position:0% +of sin x to the N is f subn of x again + + + align:start position:0% +of sin x to the N is f subn of x again +now you might be nervous because again + + align:start position:0% +now you might be nervous because again + + + align:start position:0% +now you might be nervous because again +we just said we see the same thing over + + align:start position:0% +we just said we see the same thing over + + + align:start position:0% +we just said we see the same thing over +we see what we want to reduce on the + + align:start position:0% +we see what we want to reduce on the + + + align:start position:0% +we see what we want to reduce on the +right hand side but now all we have to + + align:start position:0% +right hand side but now all we have to + + + align:start position:0% +right hand side but now all we have to +do as a little algebra so I'm going to + + align:start position:0% +do as a little algebra so I'm going to + + + align:start position:0% +do as a little algebra so I'm going to +come over and show you the magic of + + align:start position:0% +come over and show you the magic of + + + align:start position:0% +come over and show you the magic of +algebra okay let's uh let's to make this + + align:start position:0% +algebra okay let's uh let's to make this + + + align:start position:0% +algebra okay let's uh let's to make this +as easy as possible I'm going to erase + + align:start position:0% +as easy as possible I'm going to erase + + + align:start position:0% +as easy as possible I'm going to erase +the parentheses here and put that minus + + align:start position:0% +the parentheses here and put that minus + + + align:start position:0% +the parentheses here and put that minus +sign here so I don't have to rewrite the + + align:start position:0% +sign here so I don't have to rewrite the + + + align:start position:0% +sign here so I don't have to rewrite the +whole line okay so the parentheses are + + align:start position:0% +whole line okay so the parentheses are + + + align:start position:0% +whole line okay so the parentheses are +gone and I've I've distributed the + + align:start position:0% +gone and I've I've distributed the + + + align:start position:0% +gone and I've I've distributed the +negative one to both terms now notice I + + align:start position:0% +negative one to both terms now notice I + + + align:start position:0% +negative one to both terms now notice I +want to figure out what this + + align:start position:0% + + + + align:start position:0% + +is to figure out what that blue thing + + align:start position:0% +is to figure out what that blue thing + + + align:start position:0% +is to figure out what that blue thing +equals well we're back to sort of an + + align:start position:0% +equals well we're back to sort of an + + + align:start position:0% +equals well we're back to sort of an +algebra problem we can isolate the blue + + align:start position:0% +algebra problem we can isolate the blue + + + align:start position:0% +algebra problem we can isolate the blue +things and solve for what's in the blue + + align:start position:0% +things and solve for what's in the blue + + + align:start position:0% +things and solve for what's in the blue +box so that's what we're going to do so + + align:start position:0% +box so that's what we're going to do so + + + align:start position:0% +box so that's what we're going to do so +what do we have to do well we have to + + align:start position:0% +what do we have to do well we have to + + + align:start position:0% +what do we have to do well we have to +add this to the left hand side and what + + align:start position:0% +add this to the left hand side and what + + + align:start position:0% +add this to the left hand side and what +do we get let's see what we get we get 1 + + align:start position:0% +do we get let's see what we get we get 1 + + + align:start position:0% +do we get let's see what we get we get 1 ++ 1 / + + align:start position:0% + + + + align:start position:0% + +nus1 f subn of + + align:start position:0% +nus1 f subn of + + + align:start position:0% +nus1 f subn of +x is equal + + align:start position:0% +x is equal + + + align:start position:0% +x is equal +to F subn minus 2 of + + align:start position:0% +to F subn minus 2 of + + + align:start position:0% +to F subn minus 2 of +x + + align:start position:0% +x + + + align:start position:0% +x +minus cine + + align:start position:0% +minus cine + + + align:start position:0% +minus cine +X sin x to the nus1 over + + align:start position:0% +X sin x to the nus1 over + + + align:start position:0% +X sin x to the nus1 over +nus1 so all I did was I added 1 over n + + align:start position:0% +nus1 so all I did was I added 1 over n + + + align:start position:0% +nus1 so all I did was I added 1 over n +minus one time f subn of x to the left + + align:start position:0% +minus one time f subn of x to the left + + + align:start position:0% +minus one time f subn of x to the left +hand side well to both sides so it moved + + align:start position:0% +hand side well to both sides so it moved + + + align:start position:0% +hand side well to both sides so it moved +to the left hand side and there was one + + align:start position:0% +to the left hand side and there was one + + + align:start position:0% +to the left hand side and there was one +of them here and there's one over n + + align:start position:0% +of them here and there's one over n + + + align:start position:0% +of them here and there's one over n +minus one of them here and let's let's + + align:start position:0% +minus one of them here and let's let's + + + align:start position:0% +minus one of them here and let's let's +make sure we can simplify that let's see + + align:start position:0% +make sure we can simplify that let's see + + + align:start position:0% +make sure we can simplify that let's see +we get n minus1 over nus1 + 1 I think it + + align:start position:0% +we get n minus1 over nus1 + 1 I think it + + + align:start position:0% +we get n minus1 over nus1 + 1 I think it +gives me n Over N minus one so that + + align:start position:0% +gives me n Over N minus one so that + + + align:start position:0% +gives me n Over N minus one so that +gives me n Over N minus + + align:start position:0% +gives me n Over N minus + + + align:start position:0% +gives me n Over N minus +one um I guess I'll write it + + align:start position:0% +one um I guess I'll write it + + + align:start position:0% +one um I guess I'll write it +again we're really + + align:start position:0% + + + + align:start position:0% + +close and then this whole mess + + align:start position:0% + + + + align:start position:0% + +again and now we only have one more step + + align:start position:0% +again and now we only have one more step + + + align:start position:0% +again and now we only have one more step +to figure out what f subn of x is and + + align:start position:0% +to figure out what f subn of x is and + + + align:start position:0% +to figure out what f subn of x is and +that + + align:start position:0% +that + + + align:start position:0% +that +is to multiply both sides by n minus one + + align:start position:0% +is to multiply both sides by n minus one + + + align:start position:0% +is to multiply both sides by n minus one +/ n nus one over n multiplied here gives + + align:start position:0% +/ n nus one over n multiplied here gives + + + align:start position:0% +/ n nus one over n multiplied here gives +me one and so then I get nus1 / n and F + + align:start position:0% +me one and so then I get nus1 / n and F + + + align:start position:0% +me one and so then I get nus1 / n and F +of nus + + align:start position:0% +of nus + + + align:start position:0% +of nus +2 of + + align:start position:0% +2 of + + + align:start position:0% +2 of +x minus the N minus 1's kill off and I + + align:start position:0% +x minus the N minus 1's kill off and I + + + align:start position:0% +x minus the N minus 1's kill off and I +just get cine X + + align:start position:0% +just get cine X + + + align:start position:0% +just get cine X +sin to the N -1 x over + + align:start position:0% +sin to the N -1 x over + + + align:start position:0% +sin to the N -1 x over +n so this is our is our answer because + + align:start position:0% +n so this is our is our answer because + + + align:start position:0% +n so this is our is our answer because +what is the point why can I say well + + align:start position:0% +what is the point why can I say well + + + align:start position:0% +what is the point why can I say well +I've reduced it I've reduced it because + + align:start position:0% +I've reduced it I've reduced it because + + + align:start position:0% +I've reduced it I've reduced it because +I have the only integral I have is an + + align:start position:0% +I have the only integral I have is an + + + align:start position:0% +I have the only integral I have is an +integral that was a power of sinx X and + + align:start position:0% +integral that was a power of sinx X and + + + align:start position:0% +integral that was a power of sinx X and +that's the goal is that I have it in the + + align:start position:0% +that's the goal is that I have it in the + + + align:start position:0% +that's the goal is that I have it in the +form this is the power of s sin x to the + + align:start position:0% +form this is the power of s sin x to the + + + align:start position:0% +form this is the power of s sin x to the +N integrated this is sin x to the N + + align:start position:0% +N integrated this is sin x to the N + + + align:start position:0% +N integrated this is sin x to the N +minus 2 integrated and this is just a + + align:start position:0% +minus 2 integrated and this is just a + + + align:start position:0% +minus 2 integrated and this is just a +function okay and you know if we want to + + align:start position:0% +function okay and you know if we want to + + + align:start position:0% +function okay and you know if we want to +say what's the true anti-derivative we + + align:start position:0% +say what's the true anti-derivative we + + + align:start position:0% +say what's the true anti-derivative we +have to + + align:start position:0% +have to + + + align:start position:0% +have to +allow we have to allow for a plus c here + + align:start position:0% +allow we have to allow for a plus c here + + + align:start position:0% +allow we have to allow for a plus c here +for a true anti-derivative but uh but + + align:start position:0% +for a true anti-derivative but uh but + + + align:start position:0% +for a true anti-derivative but uh but +we're really interested + + align:start position:0% +we're really interested + + + align:start position:0% +we're really interested +in this part here okay because if we + + align:start position:0% +in this part here okay because if we + + + align:start position:0% +in this part here okay because if we +evaluate this at bounds that's going to + + align:start position:0% +evaluate this at bounds that's going to + + + align:start position:0% +evaluate this at bounds that's going to +go away but I want to just make sure we + + align:start position:0% +go away but I want to just make sure we + + + align:start position:0% +go away but I want to just make sure we +understand I think we understand the + + align:start position:0% +understand I think we understand the + + + align:start position:0% +understand I think we understand the +goal maybe the hardest part of this + + align:start position:0% +goal maybe the hardest part of this + + + align:start position:0% +goal maybe the hardest part of this +problem is once you come over + + align:start position:0% +problem is once you come over + + + align:start position:0% +problem is once you come over +here was once you have these two + + align:start position:0% +here was once you have these two + + + align:start position:0% +here was once you have these two +components so we did the substitution + + align:start position:0% +components so we did the substitution + + + align:start position:0% +components so we did the substitution +that seems natural you have these two + + align:start position:0% +that seems natural you have these two + + + align:start position:0% +that seems natural you have these two +components this one you should be able + + align:start position:0% +components this one you should be able + + + align:start position:0% +components this one you should be able +to recognizes in the form you want this + + align:start position:0% +to recognizes in the form you want this + + + align:start position:0% +to recognizes in the form you want this +one is the hard one to deal with but the + + align:start position:0% +one is the hard one to deal with but the + + + align:start position:0% +one is the hard one to deal with but the +trick is to see that under the right + + align:start position:0% +trick is to see that under the right + + + align:start position:0% +trick is to see that under the right +splitting up of these functions one of + + align:start position:0% +splitting up of these functions one of + + + align:start position:0% +splitting up of these functions one of +them is easy to integrate and one of + + align:start position:0% +them is easy to integrate and one of + + + align:start position:0% +them is easy to integrate and one of +them you know it's easy to integrate or + + align:start position:0% +them you know it's easy to integrate or + + + align:start position:0% +them you know it's easy to integrate or +take a derivative so I have a little bit + + align:start position:0% +take a derivative so I have a little bit + + + align:start position:0% +take a derivative so I have a little bit +of Freedom you don't want to substitute + + align:start position:0% +of Freedom you don't want to substitute + + + align:start position:0% +of Freedom you don't want to substitute +back in for cosine squared with one + + align:start position:0% +back in for cosine squared with one + + + align:start position:0% +back in for cosine squared with one +minus sin squar because it'll get you + + align:start position:0% +minus sin squar because it'll get you + + + align:start position:0% +minus sin squar because it'll get you +right back to where you started you + + align:start position:0% +right back to where you started you + + + align:start position:0% +right back to where you started you +would be like substituting one way and + + align:start position:0% +would be like substituting one way and + + + align:start position:0% +would be like substituting one way and +then substituting the other way so the + + align:start position:0% +then substituting the other way so the + + + align:start position:0% +then substituting the other way so the +goal at this point is to sort of the + + align:start position:0% +goal at this point is to sort of the + + + align:start position:0% +goal at this point is to sort of the +trick with this one I mean is this + + align:start position:0% +trick with this one I mean is this + + + align:start position:0% +trick with this one I mean is this +integration by parts which requires some + + align:start position:0% +integration by parts which requires some + + + align:start position:0% +integration by parts which requires some +substitution so hopefully this was a + + align:start position:0% +substitution so hopefully this was a + + + align:start position:0% +substitution so hopefully this was a +good exercise for you and um and you see + + align:start position:0% +good exercise for you and um and you see + + + align:start position:0% +good exercise for you and um and you see +some of the strategies that one needs to + + align:start position:0% +some of the strategies that one needs to + + + align:start position:0% +some of the strategies that one needs to +reduce the powers of of sinx you could + + align:start position:0% +reduce the powers of of sinx you could + + + align:start position:0% +reduce the powers of of sinx you could +do a very similar type of thing with + + align:start position:0% +do a very similar type of thing with + + + align:start position:0% +do a very similar type of thing with +cosine X to the end so if you felt like + + align:start position:0% +cosine X to the end so if you felt like + + + align:start position:0% +cosine X to the end so if you felt like +I'm not quite sure about this method you + + align:start position:0% +I'm not quite sure about this method you + + + align:start position:0% +I'm not quite sure about this method you +might want to try and do something + + align:start position:0% +might want to try and do something + + + align:start position:0% +might want to try and do something +similar with cosine X to the n as your + + align:start position:0% +similar with cosine X to the n as your + + + align:start position:0% +similar with cosine X to the n as your +as your uh function that you're + + align:start position:0% +as your uh function that you're + + + align:start position:0% +as your uh function that you're +integrating and see if you can reduce + + align:start position:0% +integrating and see if you can reduce + + + align:start position:0% +integrating and see if you can reduce +that and I guarantee you can find a + + align:start position:0% +that and I guarantee you can find a + + + align:start position:0% +that and I guarantee you can find a +formula for that uh in a book or online + + align:start position:0% +formula for that uh in a book or online + + + align:start position:0% +formula for that uh in a book or online +if you wanted to check that answer so I + + align:start position:0% +if you wanted to check that answer so I + + + align:start position:0% +if you wanted to check that answer so I +guess this is where I'll stop \ No newline at end of file diff --git a/imywn6EaJxg.txt b/imywn6EaJxg.txt new file mode 100644 index 0000000000000000000000000000000000000000..42ed848bad9deb229977e0ba3157ea447712aa98 --- /dev/null +++ b/imywn6EaJxg.txt @@ -0,0 +1,10969 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +to view additional materials from + + align:start position:0% +to view additional materials from + + + align:start position:0% +to view additional materials from +hundreds of MIT courses visit MIT + + align:start position:0% +hundreds of MIT courses visit MIT + + + align:start position:0% +hundreds of MIT courses visit MIT +opencourseware at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu yeah so you have Miss two + + align:start position:0% +ocw.mit.edu yeah so you have Miss two + + + align:start position:0% +ocw.mit.edu yeah so you have Miss two +semiconductors to start with uh one n + + align:start position:0% +semiconductors to start with uh one n + + + align:start position:0% +semiconductors to start with uh one n +and one one p typ and um P typ so for + + align:start position:0% +and one one p typ and um P typ so for + + + align:start position:0% +and one one p typ and um P typ so for +example you on the left hand side you + + align:start position:0% +example you on the left hand side you + + + align:start position:0% +example you on the left hand side you +have a p type the right hand side you + + align:start position:0% +have a p type the right hand side you + + + align:start position:0% +have a p type the right hand side you +have n type + + align:start position:0% +have n type + + + align:start position:0% +have n type +and there since you have a high + + align:start position:0% +and there since you have a high + + + align:start position:0% +and there since you have a high +concentration of electr on this side the + + align:start position:0% +concentration of electr on this side the + + + align:start position:0% +concentration of electr on this side the +electr jump to this side and you have a + + align:start position:0% +electr jump to this side and you have a + + + align:start position:0% +electr jump to this side and you have a +higher concentration of H the P type the + + align:start position:0% +higher concentration of H the P type the + + + align:start position:0% +higher concentration of H the P type the +P jump to the other side so you will end + + align:start position:0% +P jump to the other side so you will end + + + align:start position:0% +P jump to the other side so you will end +up with this space charge me that g + + align:start position:0% +up with this space charge me that g + + + align:start position:0% +up with this space charge me that g +talked about last + + align:start position:0% +talked about last + + + align:start position:0% +talked about last +week and um this is basically + + align:start position:0% +week and um this is basically + + + align:start position:0% +week and um this is basically +characteristic + + align:start position:0% + + + + align:start position:0% + +I just I just draw one layer + + align:start position:0% +I just I just draw one layer + + + align:start position:0% +I just I just draw one layer +see so um so B you + + align:start position:0% + + + + align:start position:0% + +have then you have + + align:start position:0% + + + + align:start position:0% + +cont impose the solar radiation + + align:start position:0% +cont impose the solar radiation + + + align:start position:0% +cont impose the solar radiation +something to + + align:start position:0% +something to + + + align:start position:0% +something to +this the volage + + align:start position:0% +this the volage + + + align:start position:0% +this the volage +you close the circuit you can generate B + + align:start position:0% +you close the circuit you can generate B + + + align:start position:0% +you close the circuit you can generate B +power for now I just talk about ciruit + + align:start position:0% +power for now I just talk about ciruit + + + align:start position:0% +power for now I just talk about ciruit +voltage so this is the first thing that + + align:start position:0% +voltage so this is the first thing that + + + align:start position:0% +voltage so this is the first thing that +happens space judge + + align:start position:0% + + + + align:start position:0% + +region and um this you basically also + + align:start position:0% +region and um this you basically also + + + align:start position:0% +region and um this you basically also +can + + align:start position:0% +can + + + align:start position:0% +can +generate vol + + align:start position:0% + + + + align:start position:0% + +so so you have the space Char right here + + align:start position:0% +so so you have the space Char right here + + + align:start position:0% +so so you have the space Char right here +and then draw for + + align:start position:0% +and then draw for + + + align:start position:0% +and then draw for +example the + + align:start position:0% + + + + align:start position:0% + +concentration and um so for the electron + + align:start position:0% +concentration and um so for the electron + + + align:start position:0% +concentration and um so for the electron +this is + + align:start position:0% + + + + align:start position:0% + +state so basic have + + align:start position:0% +state so basic have + + + align:start position:0% +state so basic have +here um you have + + align:start position:0% +here um you have + + + align:start position:0% +here um you have +ai generat + + align:start position:0% + + + + align:start position:0% + +here in case you have for example comes + + align:start position:0% +here in case you have for example comes + + + align:start position:0% +here in case you have for example comes +in talk + + align:start position:0% +in talk + + + align:start position:0% +in talk +when a comes it's ex so they still very + + align:start position:0% +when a comes it's ex so they still very + + + align:start position:0% +when a comes it's ex so they still very +close to each other these + + align:start position:0% + + + + align:start position:0% + +ex + + align:start position:0% +ex + + + align:start position:0% +ex +um they have + + align:start position:0% +um they have + + + align:start position:0% +um they have +to into this space but they + + align:start position:0% +to into this space but they + + + align:start position:0% +to into this space but they +basic um get separate so for this for + + align:start position:0% +basic um get separate so for this for + + + align:start position:0% +basic um get separate so for this for +this case for example we + + align:start position:0% + + + + align:start position:0% + +have coming um + + align:start position:0% +have coming um + + + align:start position:0% +have coming um +Direction so basically the electron will + + align:start position:0% +Direction so basically the electron will + + + align:start position:0% +Direction so basically the electron will +basically drag through this so the + + align:start position:0% +basically drag through this so the + + + align:start position:0% +basically drag through this so the +electron this direction so the + + align:start position:0% + + + + align:start position:0% + +El get separate from the hole and jumps + + align:start position:0% +El get separate from the hole and jumps + + + align:start position:0% +El get separate from the hole and jumps +on the other side and you you end up + + align:start position:0% +on the other side and you you end up + + + align:start position:0% +on the other side and you you end up +just positive charge here and um to the + + align:start position:0% +just positive charge here and um to the + + + align:start position:0% +just positive charge here and um to the +m region here have Fusion of + + align:start position:0% +m region here have Fusion of + + + align:start position:0% +m region here have Fusion of +your to the Conta here so um further so + + align:start position:0% +your to the Conta here so um further so + + + align:start position:0% +your to the Conta here so um further so +this is uh the car concentration and + + align:start position:0% +this is uh the car concentration and + + + align:start position:0% +this is uh the car concentration and +then you can also can can + + align:start position:0% + + + + align:start position:0% + +draw + + align:start position:0% + + + + align:start position:0% + +there so e is generated inside Space + + align:start position:0% +there so e is generated inside Space + + + align:start position:0% +there so e is generated inside Space +Char this + + align:start position:0% +Char this + + + align:start position:0% +Char this +[Music] + + align:start position:0% + + + + align:start position:0% + +and I think this was also when you + + align:start position:0% +and I think this was also when you + + + align:start position:0% +and I think this was also when you +talked about the + + align:start position:0% + + + + align:start position:0% + +last + + align:start position:0% +last + + + align:start position:0% +last +about just + + align:start position:0% +about just + + + align:start position:0% +about just +umal expansion + + align:start position:0% +umal expansion + + + align:start position:0% +umal expansion +um of + + align:start position:0% +um of + + + align:start position:0% +um of +this Bally say + + align:start position:0% +this Bally say + + + align:start position:0% +this Bally say +um + + align:start position:0% +um + + + align:start position:0% +um +this + + align:start position:0% + + + + align:start position:0% + +drop just say up to certain point drop + + align:start position:0% +drop just say up to certain point drop + + + align:start position:0% +drop just say up to certain point drop +down + + align:start position:0% + + + + align:start position:0% + +C up to this point exit when it comes it + + align:start position:0% +C up to this point exit when it comes it + + + align:start position:0% +C up to this point exit when it comes it +will start + + align:start position:0% +will start + + + align:start position:0% +will start +feeling space charge + + align:start position:0% + + + + align:start position:0% + +and then I wanted to talk about so in + + align:start position:0% +and then I wanted to talk about so in + + + align:start position:0% +and then I wanted to talk about so in +the real case we actually have + + align:start position:0% + + + + align:start position:0% + +pH the so when we join the when we join + + align:start position:0% +pH the so when we join the when we join + + + align:start position:0% +pH the so when we join the when we join +two the last Le + + align:start position:0% + + + + align:start position:0% + +we since the + + align:start position:0% +we since the + + + align:start position:0% +we since the +family + + align:start position:0% + + + + align:start position:0% + +same let see what happens is + + align:start position:0% + + + + align:start position:0% + +um it's basically + + align:start position:0% + + + + align:start position:0% + +exed at the same I mean gets SE first + + align:start position:0% +exed at the same I mean gets SE first + + + align:start position:0% +exed at the same I mean gets SE first +you have this this state EXC State and + + align:start position:0% +you have this this state EXC State and + + + align:start position:0% +you have this this state EXC State and +then when CL St + + align:start position:0% + + + + align:start position:0% + +SE um changes with Lev so what you end + + align:start position:0% +SE um changes with Lev so what you end + + + align:start position:0% +SE um changes with Lev so what you end +up + + align:start position:0% + + + + align:start position:0% + +ises and when you remove an El here you + + align:start position:0% +ises and when you remove an El here you + + + align:start position:0% +ises and when you remove an El here you +end up with ho here so you basically + + align:start position:0% +end up with ho here so you basically + + + align:start position:0% +end up with ho here so you basically +decreas so end up + + align:start position:0% +decreas so end up + + + align:start position:0% +decreas so end up +some Med is + + align:start position:0% + + + + align:start position:0% + +and this is basically the we see so the + + align:start position:0% +and this is basically the we see so the + + + align:start position:0% +and this is basically the we see so the +difference between these two due to + + align:start position:0% + + + + align:start position:0% + +thech the IDE obvious + + align:start position:0% +thech the IDE obvious + + + align:start position:0% +thech the IDE obvious +basically go all the way so maximum + + align:start position:0% +basically go all the way so maximum + + + align:start position:0% +basically go all the way so maximum +open get + + align:start position:0% + + + + align:start position:0% + +so the elction go conduction band is + + align:start position:0% + + + + align:start position:0% + +because what was the question uh so + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +yeah that's that's a good question I was + + align:start position:0% +yeah that's that's a good question I was + + + align:start position:0% +yeah that's that's a good question I was +thinking about that too whe it's + + align:start position:0% +thinking about that too whe it's + + + align:start position:0% +thinking about that too whe it's +actually a step like this and then go + + align:start position:0% +actually a step like this and then go + + + align:start position:0% +actually a step like this and then go +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +um very good question I think I can + + align:start position:0% + + + + align:start position:0% + +yeah well it's a it's a distributor so + + align:start position:0% +yeah well it's a it's a distributor so + + + align:start position:0% +yeah well it's a it's a distributor so +this one you should not look at the uh + + align:start position:0% +this one you should not look at the uh + + + align:start position:0% +this one you should not look at the uh +the spaceship so it's locally it could + + align:start position:0% +the spaceship so it's locally it could + + + align:start position:0% +the spaceship so it's locally it could +be anywhere around that + + align:start position:0% +be anywhere around that + + + align:start position:0% +be anywhere around that +curve + + align:start position:0% +curve + + + align:start position:0% +curve +the so uh I I think that's a good place + + align:start position:0% +the so uh I I think that's a good place + + + align:start position:0% +the so uh I I think that's a good place +I I think back same + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +so uh that's where we stopped uh the + + align:start position:0% +so uh that's where we stopped uh the + + + align:start position:0% +so uh that's where we stopped uh the +last + + align:start position:0% +last + + + align:start position:0% +last +lecture uh it's about the + + align:start position:0% +lecture uh it's about the + + + align:start position:0% +lecture uh it's about the +compar + + align:start position:0% +compar + + + align:start position:0% +compar +umj a diet + + align:start position:0% +umj a diet + + + align:start position:0% +umj a diet +there a sh barrier sh about on the left + + align:start position:0% +there a sh barrier sh about on the left + + + align:start position:0% +there a sh barrier sh about on the left +is a sh on the + + align:start position:0% +is a sh on the + + + align:start position:0% +is a sh on the +right and when you look at the current + + align:start position:0% +right and when you look at the current + + + align:start position:0% +right and when you look at the current +voltage characteristics looks very + + align:start position:0% +voltage characteristics looks very + + + align:start position:0% +voltage characteristics looks very +similar right except that the + + align:start position:0% +similar right except that the + + + align:start position:0% +similar right except that the +coefficient are different the saturation + + align:start position:0% +coefficient are different the saturation + + + align:start position:0% +coefficient are different the saturation +This Is Us saturation C and saturation + + align:start position:0% +This Is Us saturation C and saturation + + + align:start position:0% +This Is Us saturation C and saturation +for uh this is a metal semiconductor + + align:start position:0% +for uh this is a metal semiconductor + + + align:start position:0% +for uh this is a metal semiconductor +right uh + + align:start position:0% +right uh + + + align:start position:0% +right uh +Junction and in + + align:start position:0% + + + + align:start position:0% + +ofation uh and in the case + + align:start position:0% +ofation uh and in the case + + + align:start position:0% +ofation uh and in the case +of + + align:start position:0% +of + + + align:start position:0% +of +thejunction the card include the B Gap + + align:start position:0% +thejunction the card include the B Gap + + + align:start position:0% +thejunction the card include the B Gap +and include the effusivity of hole so on + + align:start position:0% +and include the effusivity of hole so on + + + align:start position:0% +and include the effusivity of hole so on +the P side is a really hole that PR the + + align:start position:0% +the P side is a really hole that PR the + + + align:start position:0% +the P side is a really hole that PR the +car on the inside is the electron so if + + align:start position:0% +car on the inside is the electron so if + + + align:start position:0% +car on the inside is the electron so if +you elect + + align:start position:0% + + + + align:start position:0% + +inside and then we have this one time + + align:start position:0% +inside and then we have this one time + + + align:start position:0% +inside and then we have this one time +the comination time uh this is a uh say + + align:start position:0% +the comination time uh this is a uh say + + + align:start position:0% +the comination time uh this is a uh say +when you create a + + align:start position:0% +when you create a + + + align:start position:0% +when you create a +electron you excite the + + align:start position:0% +electron you excite the + + + align:start position:0% +electron you excite the +electron from Val to conduction + + align:start position:0% +electron from Val to conduction + + + align:start position:0% +electron from Val to conduction +conduction but how long they can be kep + + align:start position:0% +conduction but how long they can be kep + + + align:start position:0% +conduction but how long they can be kep +separate and after amount of time they + + align:start position:0% +separate and after amount of time they + + + align:start position:0% +separate and after amount of time they +will Rec + + align:start position:0% +will Rec + + + align:start position:0% +will Rec +combine and give us the either for + + align:start position:0% +combine and give us the either for + + + align:start position:0% +combine and give us the either for +that's where laser + + align:start position:0% +that's where laser + + + align:start position:0% +that's where laser +or you want or uh give ke uh the general + + align:start position:0% +or you want or uh give ke uh the general + + + align:start position:0% +or you want or uh give ke uh the general +forms so uh this is the recombination + + align:start position:0% +forms so uh this is the recombination + + + align:start position:0% +forms so uh this is the recombination +time for and you can see that the + + align:start position:0% +time for and you can see that the + + + align:start position:0% +time for and you can see that the +difference really in this saturation + + align:start position:0% +difference really in this saturation + + + align:start position:0% +difference really in this saturation +that Cur and sometimes equal + + align:start position:0% +that Cur and sometimes equal + + + align:start position:0% +that Cur and sometimes equal +for matics + + align:start position:0% +for matics + + + align:start position:0% +for matics +but I want to emphasize another + + align:start position:0% +but I want to emphasize another + + + align:start position:0% +but I want to emphasize another +fundamental + + align:start position:0% +fundamental + + + align:start position:0% +fundamental +yes I would sort of intuitively that the + + align:start position:0% +yes I would sort of intuitively that the + + + align:start position:0% +yes I would sort of intuitively that the +longer the recombination time the more + + align:start position:0% +longer the recombination time the more + + + align:start position:0% +longer the recombination time the more +current we would have the longer the the + + align:start position:0% +current we would have the longer the the + + + align:start position:0% +current we would have the longer the the +longer the rec relation time yes let's + + align:start position:0% +longer the rec relation time yes let's + + + align:start position:0% +longer the rec relation time yes let's +see uh recombination is also related to + + align:start position:0% +see uh recombination is also related to + + + align:start position:0% +see uh recombination is also related to +um U + + align:start position:0% +um U + + + align:start position:0% +um U +uh longer Rec + + align:start position:0% +uh longer Rec + + + align:start position:0% +uh longer Rec +comilation uh + + align:start position:0% +comilation uh + + + align:start position:0% +comilation uh +well longer recombination uh uh + + align:start position:0% +well longer recombination uh uh + + + align:start position:0% +well longer recombination uh uh +smaller uh um uh not + + align:start position:0% +smaller uh um uh not + + + align:start position:0% +smaller uh um uh not +C but say I see your point uh where if + + align:start position:0% +C but say I see your point uh where if + + + align:start position:0% +C but say I see your point uh where if +the the + + align:start position:0% +the the + + + align:start position:0% +the the +longer uh is + + align:start position:0% + + + + align:start position:0% + +reculation reculation happens in this + + align:start position:0% +reculation reculation happens in this + + + align:start position:0% +reculation reculation happens in this +region okay so + + align:start position:0% +region okay so + + + align:start position:0% +region okay so +um uh I think in that case what happens + + align:start position:0% +um uh I think in that case what happens + + + align:start position:0% +um uh I think in that case what happens +is the diffusion Supply is also uh limit + + align:start position:0% +is the diffusion Supply is also uh limit + + + align:start position:0% +is the diffusion Supply is also uh limit +your your your uh current flow so this + + align:start position:0% +your your your uh current flow so this + + + align:start position:0% +your your your uh current flow so this +is where I want to emphasize the + + align:start position:0% +is where I want to emphasize the + + + align:start position:0% +is where I want to emphasize the +important difference between this two + + align:start position:0% +important difference between this two + + + align:start position:0% +important difference between this two +formula is a sh barrier when electron go + + align:start position:0% +formula is a sh barrier when electron go + + + align:start position:0% +formula is a sh barrier when electron go +from here to here right it's electron + + align:start position:0% +from here to here right it's electron + + + align:start position:0% +from here to here right it's electron +still + + align:start position:0% +still + + + align:start position:0% +still +elect the way I draw it here is the + + align:start position:0% +elect the way I draw it here is the + + + align:start position:0% +elect the way I draw it here is the +electron and the M side is electron no + + align:start position:0% +electron and the M side is electron no + + + align:start position:0% +electron and the M side is electron no +problem + + align:start position:0% +problem + + + align:start position:0% +problem +now if you look at the K + + align:start position:0% +now if you look at the K + + + align:start position:0% +now if you look at the K +Junction okay on the end Ty is + + align:start position:0% +Junction okay on the end Ty is + + + align:start position:0% +Junction okay on the end Ty is +electron and then T + + align:start position:0% +electron and then T + + + align:start position:0% +electron and then T +typ so if electron go I'm dra here + + align:start position:0% +typ so if electron go I'm dra here + + + align:start position:0% +typ so if electron go I'm dra here +electron go from here to here go through + + align:start position:0% +electron go from here to here go through + + + align:start position:0% +electron go from here to here go through +this space charge + + align:start position:0% +this space charge + + + align:start position:0% +this space charge +region there's no more + + align:start position:0% +region there's no more + + + align:start position:0% +region there's no more +electron right you have to + + align:start position:0% +electron right you have to + + + align:start position:0% +electron right you have to +P so what happens + + align:start position:0% +P so what happens + + + align:start position:0% +P so what happens +and you have to have current continuity + + align:start position:0% +and you have to have current continuity + + + align:start position:0% +and you have to have current continuity +the charge has to be supplied + + align:start position:0% +the charge has to be supplied + + + align:start position:0% +the charge has to be supplied +right so what happens is that the + + align:start position:0% +right so what happens is that the + + + align:start position:0% +right so what happens is that the +hole will Rec combine with this + + align:start position:0% +hole will Rec combine with this + + + align:start position:0% +hole will Rec combine with this +electron okay so the ho we combined with + + align:start position:0% +electron okay so the ho we combined with + + + align:start position:0% +electron okay so the ho we combined with +the electron that means you have to + + align:start position:0% +the electron that means you have to + + + align:start position:0% +the electron that means you have to +supply holes from this side so you draw + + align:start position:0% +supply holes from this side so you draw + + + align:start position:0% +supply holes from this side so you draw +hole from this side we combine with + + align:start position:0% +hole from this side we combine with + + + align:start position:0% +hole from this side we combine with +whatever electron come this side + + align:start position:0% +whatever electron come this side + + + align:start position:0% +whatever electron come this side +and this is the where the recompilation + + align:start position:0% +and this is the where the recompilation + + + align:start position:0% +and this is the where the recompilation +reg happen it's not in the space chart + + align:start position:0% +reg happen it's not in the space chart + + + align:start position:0% +reg happen it's not in the space chart +it's slightly just outside the space + + align:start position:0% +it's slightly just outside the space + + + align:start position:0% +it's slightly just outside the space +chart so it's minority carrier + + align:start position:0% +chart so it's minority carrier + + + align:start position:0% +chart so it's minority carrier +device that's really fundamental + + align:start position:0% +device that's really fundamental + + + align:start position:0% +device that's really fundamental +difference between majority carrier + + align:start position:0% +difference between majority carrier + + + align:start position:0% +difference between majority carrier +device minority device minority device + + align:start position:0% +device minority device minority device + + + align:start position:0% +device minority device minority device +this Rec comilation is crucial and later + + align:start position:0% +this Rec comilation is crucial and later + + + align:start position:0% +this Rec comilation is crucial and later +on we talk about solar cell that's all + + align:start position:0% +on we talk about solar cell that's all + + + align:start position:0% +on we talk about solar cell that's all +people trying to refine solar silicon is + + align:start position:0% +people trying to refine solar silicon is + + + align:start position:0% +people trying to refine solar silicon is +trying to increase + + align:start position:0% +trying to increase + + + align:start position:0% +trying to increase +this Rec + + align:start position:0% +this Rec + + + align:start position:0% +this Rec +combination okay so that's that's a so + + align:start position:0% +combination okay so that's that's a so + + + align:start position:0% +combination okay so that's that's a so +you brought this this is the point + + align:start position:0% +you brought this this is the point + + + align:start position:0% +you brought this this is the point +that's really important to uh to + + align:start position:0% +that's really important to uh to + + + align:start position:0% +that's really important to uh to +appreciate the + + align:start position:0% + + + + align:start position:0% + +minority okay and of course I mention so + + align:start position:0% +minority okay and of course I mention so + + + align:start position:0% +minority okay and of course I mention so +this is what I draw the C you can + + align:start position:0% + + + + align:start position:0% + +say + + align:start position:0% +say + + + align:start position:0% +say +diffusion is on this side so whole + + align:start position:0% +diffusion is on this side so whole + + + align:start position:0% +diffusion is on this side so whole +diffus one just this side there's no + + align:start position:0% +diffus one just this side there's no + + + align:start position:0% +diffus one just this side there's no +more electron right so electron will Rec + + align:start position:0% +more electron right so electron will Rec + + + align:start position:0% +more electron right so electron will Rec +combin with so there's next electron FL + + align:start position:0% +combin with so there's next electron FL + + + align:start position:0% +combin with so there's next electron FL +forward so there small so if I look at + + align:start position:0% +forward so there small so if I look at + + + align:start position:0% +forward so there small so if I look at +electron Cur it dease in this + + align:start position:0% + + + + align:start position:0% + +combination and then I look at the whole + + align:start position:0% +combination and then I look at the whole + + + align:start position:0% +combination and then I look at the whole +current right say on this side the whole + + align:start position:0% +current right say on this side the whole + + + align:start position:0% +current right say on this side the whole +difference in this that's where the + + align:start position:0% +difference in this that's where the + + + align:start position:0% +difference in this that's where the +supply we comb + + align:start position:0% +supply we comb + + + align:start position:0% +supply we comb +with so go through the space Char reg + + align:start position:0% +with so go through the space Char reg + + + align:start position:0% +with so go through the space Char reg +space Char + + align:start position:0% +space Char + + + align:start position:0% +space Char +comination so as approximation so it's a + + align:start position:0% +comination so as approximation so it's a + + + align:start position:0% +comination so as approximation so it's a +constant and then after space charge + + align:start position:0% +constant and then after space charge + + + align:start position:0% +constant and then after space charge +they Rec combine with the pole so + + align:start position:0% +they Rec combine with the pole so + + + align:start position:0% +they Rec combine with the pole so +electron diminish now and this side is + + align:start position:0% +electron diminish now and this side is + + + align:start position:0% +electron diminish now and this side is +just + + align:start position:0% +just + + + align:start position:0% +just +over right so that's how we go trans + + align:start position:0% +over right so that's how we go trans + + + align:start position:0% +over right so that's how we go trans +from a electron + + align:start position:0% +from a electron + + + align:start position:0% +from a electron +to so K Jun Theory shly uh uh say you + + align:start position:0% +to so K Jun Theory shly uh uh say you + + + align:start position:0% +to so K Jun Theory shly uh uh say you +know injunction was I think I say three + + align:start position:0% +know injunction was I think I say three + + + align:start position:0% +know injunction was I think I say three +people got Rob Price uh one is the sh + + align:start position:0% +people got Rob Price uh one is the sh + + + align:start position:0% +people got Rob Price uh one is the sh +and the other is bin and the third is + + align:start position:0% +and the other is bin and the third is + + + align:start position:0% +and the other is bin and the third is +BR and I think it was sh + + align:start position:0% +BR and I think it was sh + + + align:start position:0% +BR and I think it was sh +and uh shle and Britain did the invation + + align:start position:0% +and uh shle and Britain did the invation + + + align:start position:0% +and uh shle and Britain did the invation +and B was the manager at time + + align:start position:0% +and B was the manager at time + + + align:start position:0% +and B was the manager at time +of + + align:start position:0% +of + + + align:start position:0% +of +develop and if you look at the the + + align:start position:0% +develop and if you look at the the + + + align:start position:0% +develop and if you look at the the +history + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% + + + + align:start position:0% + +only + + align:start position:0% +only + + + align:start position:0% +only +superity so he was very + + align:start position:0% +superity so he was very + + + align:start position:0% +superity so he was very +history as manager this is so important + + align:start position:0% +history as manager this is so important + + + align:start position:0% +history as manager this is so important +has to do something if you Theory okay + + align:start position:0% +has to do something if you Theory okay + + + align:start position:0% +has to do something if you Theory okay +and but this is really a very ingenious + + align:start position:0% +and but this is really a very ingenious + + + align:start position:0% +and but this is really a very ingenious +Theory to think about how + + align:start position:0% +Theory to think about how + + + align:start position:0% +Theory to think about how +electron on this side know on other + + align:start position:0% +electron on this side know on other + + + align:start position:0% +electron on this side know on other +by the end your curent has to be + + align:start position:0% +by the end your curent has to be + + + align:start position:0% +by the end your curent has to be +continued the summation of electron Cur + + align:start position:0% +continued the summation of electron Cur + + + align:start position:0% +continued the summation of electron Cur +the whole current is Con + + align:start position:0% +the whole current is Con + + + align:start position:0% +the whole current is Con +right okay and uh in the last lecture I + + align:start position:0% +right okay and uh in the last lecture I + + + align:start position:0% +right okay and uh in the last lecture I +also said if you look at the energy + + align:start position:0% +also said if you look at the energy + + + align:start position:0% +also said if you look at the energy +flow and when electron right here yes I + + align:start position:0% +flow and when electron right here yes I + + + align:start position:0% +flow and when electron right here yes I +would like to know what happens the + + align:start position:0% +would like to know what happens the + + + align:start position:0% +would like to know what happens the +whole Curr in the contact because in the + + align:start position:0% +whole Curr in the contact because in the + + + align:start position:0% +whole Curr in the contact because in the +cbles we must have elect right of in the + + align:start position:0% +cbles we must have elect right of in the + + + align:start position:0% +cbles we must have elect right of in the +uh in the + + align:start position:0% +uh in the + + + align:start position:0% +uh in the +contact very so it's a it's a matter of + + align:start position:0% +contact very so it's a it's a matter of + + + align:start position:0% +contact very so it's a it's a matter of +there's no hole again there's no hole so + + align:start position:0% +there's no hole again there's no hole so + + + align:start position:0% +there's no hole again there's no hole so +if typically contact people want to make + + align:start position:0% +if typically contact people want to make + + + align:start position:0% +if typically contact people want to make +an army contact so what what H what + + align:start position:0% +an army contact so what what H what + + + align:start position:0% +an army contact so what what H what +happens is when uh uh uh so the whole + + align:start position:0% +happens is when uh uh uh so the whole + + + align:start position:0% +happens is when uh uh uh so the whole +motion is really majority of electron + + align:start position:0% +motion is really majority of electron + + + align:start position:0% +motion is really majority of electron +Motion in the t region so when po move + + align:start position:0% +Motion in the t region so when po move + + + align:start position:0% +Motion in the t region so when po move +this way go uh from Whole Mo from here + + align:start position:0% +this way go uh from Whole Mo from here + + + align:start position:0% +this way go uh from Whole Mo from here +to here that means this electron goes + + align:start position:0% +to here that means this electron goes + + + align:start position:0% +to here that means this electron goes +out to the + + align:start position:0% +out to the + + + align:start position:0% +out to the +metal so that's what + + align:start position:0% +metal so that's what + + + align:start position:0% +metal so that's what +happens okay and they have full chal + + align:start position:0% +happens okay and they have full chal + + + align:start position:0% +happens okay and they have full chal +potential electral potential that's what + + align:start position:0% +potential electral potential that's what + + + align:start position:0% +potential electral potential that's what +say Junction sort of like the CH bar but + + align:start position:0% +say Junction sort of like the CH bar but + + + align:start position:0% +say Junction sort of like the CH bar but +they want make Armic + + align:start position:0% +they want make Armic + + + align:start position:0% +they want make Armic +Junction those + + align:start position:0% +Junction those + + + align:start position:0% +Junction those +sides and if you think about the C + + align:start position:0% +sides and if you think about the C + + + align:start position:0% +sides and if you think about the C +effect right Pro he is the kinetic + + align:start position:0% +effect right Pro he is the kinetic + + + align:start position:0% +effect right Pro he is the kinetic +energy part which is 2 + + align:start position:0% +energy part which is 2 + + + align:start position:0% +energy part which is 2 +KT of the charge average + + align:start position:0% +KT of the charge average + + + align:start position:0% +KT of the charge average +speaking minus + + align:start position:0% + + + + align:start position:0% + +EA + + align:start position:0% +EA + + + align:start position:0% +EA +EA minus EF right the C + + align:start position:0% +EA minus EF right the C + + + align:start position:0% +EA minus EF right the C +energy and you look at this EC and EF is + + align:start position:0% +energy and you look at this EC and EF is + + + align:start position:0% +energy and you look at this EC and EF is +growing here on the inside e EF is here + + align:start position:0% +growing here on the inside e EF is here + + + align:start position:0% +growing here on the inside e EF is here +in this space charge reg is grow larger + + align:start position:0% +in this space charge reg is grow larger + + + align:start position:0% +in this space charge reg is grow larger +larger so electron is carrying more heat + + align:start position:0% +larger so electron is carrying more heat + + + align:start position:0% +larger so electron is carrying more heat +per charge is carrying more + + align:start position:0% +per charge is carrying more + + + align:start position:0% +per charge is carrying more +heat right it's carrying he out of the + + align:start position:0% +heat right it's carrying he out of the + + + align:start position:0% +heat right it's carrying he out of the +space charge + + align:start position:0% +space charge + + + align:start position:0% +space charge +region that's why space charge region is + + align:start position:0% +region that's why space charge region is + + + align:start position:0% +region that's why space charge region is +actually + + align:start position:0% +actually + + + align:start position:0% +actually +a okay and then in outside immediate + + align:start position:0% +a okay and then in outside immediate + + + align:start position:0% +a okay and then in outside immediate +outside space charge region + + align:start position:0% +outside space charge region + + + align:start position:0% +outside space charge region +recompilation happens right + + align:start position:0% +recompilation happens right + + + align:start position:0% +recompilation happens right +recombination dump the H just immediate + + align:start position:0% +recombination dump the H just immediate + + + align:start position:0% +recombination dump the H just immediate +outside space charger we flow back of + + align:start position:0% +outside space charger we flow back of + + + align:start position:0% +outside space charger we flow back of +course Junction heats up but physics is + + align:start position:0% +course Junction heats up but physics is + + + align:start position:0% +course Junction heats up but physics is +it's not the junction the space charge + + align:start position:0% +it's not the junction the space charge + + + align:start position:0% +it's not the junction the space charge +region that really heats up the heat is + + align:start position:0% +region that really heats up the heat is + + + align:start position:0% +region that really heats up the heat is +actually generated + + align:start position:0% +actually generated + + + align:start position:0% +actually generated +outside this space charge in this Rec + + align:start position:0% +outside this space charge in this Rec + + + align:start position:0% +outside this space charge in this Rec +comilation this is where heat + + align:start position:0% + + + + align:start position:0% + +is that's a fact that most people + + align:start position:0% +is that's a fact that most people + + + align:start position:0% +is that's a fact that most people +probably + + align:start position:0% + + + + align:start position:0% + +know + + align:start position:0% +know + + + align:start position:0% +know +okay so uh uh to finish what I was + + align:start position:0% +okay so uh uh to finish what I was + + + align:start position:0% +okay so uh uh to finish what I was +talking last lecture more research this + + align:start position:0% +talking last lecture more research this + + + align:start position:0% +talking last lecture more research this +is the basic physics + + align:start position:0% +is the basic physics + + + align:start position:0% +is the basic physics +and since we're talking about the re + + align:start position:0% +and since we're talking about the re + + + align:start position:0% +and since we're talking about the re +formula emission so uh there are people + + align:start position:0% +formula emission so uh there are people + + + align:start position:0% +formula emission so uh there are people +doing for example in the this is a + + align:start position:0% +doing for example in the this is a + + + align:start position:0% +doing for example in the this is a +conduction F if you don't have a fir + + align:start position:0% +conduction F if you don't have a fir + + + align:start position:0% +conduction F if you don't have a fir +number around this place the energy + + align:start position:0% +number around this place the energy + + + align:start position:0% +number around this place the energy +electron below the fir level is actually + + align:start position:0% +electron below the fir level is actually + + + align:start position:0% +electron below the fir level is actually +carry negative energy and the electron + + align:start position:0% +carry negative energy and the electron + + + align:start position:0% +carry negative energy and the electron +above carry positive energy + + align:start position:0% +above carry positive energy + + + align:start position:0% +above carry positive energy +so one idea is if I do a shock barrier + + align:start position:0% +so one idea is if I do a shock barrier + + + align:start position:0% +so one idea is if I do a shock barrier +or potential barrier right and I just + + align:start position:0% +or potential barrier right and I just + + + align:start position:0% +or potential barrier right and I just +scatter this part of the electron that's + + align:start position:0% +scatter this part of the electron that's + + + align:start position:0% +scatter this part of the electron that's +called Energy filter or depends on if + + align:start position:0% +called Energy filter or depends on if + + + align:start position:0% +called Energy filter or depends on if +you have interface you also call it + + align:start position:0% +you have interface you also call it + + + align:start position:0% +you have interface you also call it +emission so some people call the + + align:start position:0% +emission so some people call the + + + align:start position:0% +emission so some people call the +emission say + + align:start position:0% +emission say + + + align:start position:0% +emission say +thric effect the soal solidate teric but + + align:start position:0% +thric effect the soal solidate teric but + + + align:start position:0% +thric effect the soal solidate teric but +say uh essentially + + align:start position:0% +say uh essentially + + + align:start position:0% +say uh essentially +of the low energy electron or sometimes + + align:start position:0% +of the low energy electron or sometimes + + + align:start position:0% +of the low energy electron or sometimes +carry heat because the electron below + + align:start position:0% +carry heat because the electron below + + + align:start position:0% +carry heat because the electron below +the CH + + align:start position:0% +the CH + + + align:start position:0% +the CH +Po and if I draw the + + align:start position:0% +Po and if I draw the + + + align:start position:0% +Po and if I draw the +stat most I I mentioned before talk + + align:start position:0% +stat most I I mentioned before talk + + + align:start position:0% +stat most I I mentioned before talk +electric stat need a sharp feature the + + align:start position:0% +electric stat need a sharp feature the + + + align:start position:0% +electric stat need a sharp feature the +sharp feature help increases thric + + align:start position:0% +sharp feature help increases thric + + + align:start position:0% +sharp feature help increases thric +effect right so the way I view is okay + + align:start position:0% +effect right so the way I view is okay + + + align:start position:0% +effect right so the way I view is okay +in this I cut it off by transport I cut + + align:start position:0% +in this I cut it off by transport I cut + + + align:start position:0% +in this I cut it off by transport I cut +off transport electrons I still have the + + align:start position:0% +off transport electrons I still have the + + + align:start position:0% +off transport electrons I still have the +electron but they are scatter they don't + + align:start position:0% +electron but they are scatter they don't + + + align:start position:0% +electron but they are scatter they don't +move so then uh the real ones are here + + align:start position:0% +move so then uh the real ones are here + + + align:start position:0% +move so then uh the real ones are here +and I can think this sh so that's the + + align:start position:0% +and I can think this sh so that's the + + + align:start position:0% +and I can think this sh so that's the +way I say okay it's all really coming + + align:start position:0% +way I say okay it's all really coming + + + align:start position:0% +way I say okay it's all really coming +back to the idea if you can create a sh + + align:start position:0% +back to the idea if you can create a sh + + + align:start position:0% +back to the idea if you can create a sh +features in this sub States put a lot of + + align:start position:0% +features in this sub States put a lot of + + + align:start position:0% +features in this sub States put a lot of +electron there and you can potentially + + align:start position:0% +electron there and you can potentially + + + align:start position:0% +electron there and you can potentially +improve the electron um car Factor + + align:start position:0% +improve the electron um car Factor + + + align:start position:0% +improve the electron um car Factor +that's for signal but see the key is you + + align:start position:0% +that's for signal but see the key is you + + + align:start position:0% +that's for signal but see the key is you +don't want you only want to scare this + + align:start position:0% +don't want you only want to scare this + + + align:start position:0% +don't want you only want to scare this +part you don't want to this part do it + + align:start position:0% +part you don't want to this part do it + + + align:start position:0% +part you don't want to this part do it +that's a still a lot of TRS I think that + + align:start position:0% +that's a still a lot of TRS I think that + + + align:start position:0% +that's a still a lot of TRS I think that +this this idea here not fully convincing + + align:start position:0% +this this idea here not fully convincing + + + align:start position:0% +this this idea here not fully convincing +yet + + align:start position:0% +yet + + + align:start position:0% +yet +me and I made a few slides on this + + align:start position:0% +me and I made a few slides on this + + + align:start position:0% +me and I made a few slides on this +that's on my own uh sort of toy baby I I + + align:start position:0% +that's on my own uh sort of toy baby I I + + + align:start position:0% +that's on my own uh sort of toy baby I I +published a paper before uh um there's + + align:start position:0% +published a paper before uh um there's + + + align:start position:0% +published a paper before uh um there's +no experiment maybe some of you + + align:start position:0% +no experiment maybe some of you + + + align:start position:0% +no experiment maybe some of you +interested but this is the issue I what + + align:start position:0% +interested but this is the issue I what + + + align:start position:0% +interested but this is the issue I what +is the evaporation right I said that the + + align:start position:0% +is the evaporation right I said that the + + + align:start position:0% +is the evaporation right I said that the +uh electron no the modle coming out of + + align:start position:0% +uh electron no the modle coming out of + + + align:start position:0% +uh electron no the modle coming out of +the liquid surface that's like a + + align:start position:0% +the liquid surface that's like a + + + align:start position:0% +the liquid surface that's like a +evaporation uh that's equivalent to Ser + + align:start position:0% +evaporation uh that's equivalent to Ser + + + align:start position:0% +evaporation uh that's equivalent to Ser +emission let's say uh the how about I + + align:start position:0% +emission let's say uh the how about I + + + align:start position:0% +emission let's say uh the how about I +have a vacuum here right I got a liquid + + align:start position:0% +have a vacuum here right I got a liquid + + + align:start position:0% +have a vacuum here right I got a liquid +here and sudden a drop of liquid drop + + align:start position:0% +here and sudden a drop of liquid drop + + + align:start position:0% +here and sudden a drop of liquid drop +into the vacuum C every it suddenly + + align:start position:0% +into the vacuum C every it suddenly + + + align:start position:0% +into the vacuum C every it suddenly +expand is that a corresponding to + + align:start position:0% +expand is that a corresponding to + + + align:start position:0% +expand is that a corresponding to +evaporation and I have a s case where + + align:start position:0% +evaporation and I have a s case where + + + align:start position:0% +evaporation and I have a s case where +I'm comparing this two examples and this + + align:start position:0% +I'm comparing this two examples and this + + + align:start position:0% +I'm comparing this two examples and this +two example is one is a cionic barrier + + align:start position:0% +two example is one is a cionic barrier + + + align:start position:0% +two example is one is a cionic barrier +as everybody before when electron flow + + align:start position:0% +as everybody before when electron flow + + + align:start position:0% +as everybody before when electron flow +this way the low energ electron in this + + align:start position:0% +this way the low energ electron in this + + + align:start position:0% +this way the low energ electron in this +is + + align:start position:0% + + + + align:start position:0% + +SC the other case I consider this was + + align:start position:0% +SC the other case I consider this was + + + align:start position:0% +SC the other case I consider this was +actually Pap General Physics is what + + align:start position:0% +actually Pap General Physics is what + + + align:start position:0% +actually Pap General Physics is what +about I flow electron this way and + + align:start position:0% +about I flow electron this way and + + + align:start position:0% +about I flow electron this way and +suddenly drop a letter and that mean to + + align:start position:0% +suddenly drop a letter and that mean to + + + align:start position:0% +suddenly drop a letter and that mean to +me is more like I take a drop put the + + align:start position:0% +me is more like I take a drop put the + + + align:start position:0% +me is more like I take a drop put the +vacuum suddenly + + align:start position:0% +vacuum suddenly + + + align:start position:0% +vacuum suddenly +evaporate and this one is more like a + + align:start position:0% +evaporate and this one is more like a + + + align:start position:0% +evaporate and this one is more like a +water surface and the water Mo coming + + align:start position:0% +water surface and the water Mo coming + + + align:start position:0% +water surface and the water Mo coming +out of surface like cool water right so + + align:start position:0% +out of surface like cool water right so + + + align:start position:0% +out of surface like cool water right so +um uh that's a solid state analogy that + + align:start position:0% +um uh that's a solid state analogy that + + + align:start position:0% +um uh that's a solid state analogy that +we're trying to make so what I did is I + + align:start position:0% +we're trying to make so what I did is I + + + align:start position:0% +we're trying to make so what I did is I +did some energy balance analysis + + align:start position:0% +did some energy balance analysis + + + align:start position:0% +did some energy balance analysis +essentially a recharge and + + align:start position:0% +essentially a recharge and + + + align:start position:0% +essentially a recharge and +formula high and you can do you can + + align:start position:0% +formula high and you can do you can + + + align:start position:0% +formula high and you can do you can +assume the two sides has different + + align:start position:0% +assume the two sides has different + + + align:start position:0% +assume the two sides has different +temperature even on the both sides and + + align:start position:0% +temperature even on the both sides and + + + align:start position:0% +temperature even on the both sides and +different C + + align:start position:0% +different C + + + align:start position:0% +different C +potential the real way to do this Sol + + align:start position:0% +potential the real way to do this Sol + + + align:start position:0% +potential the real way to do this Sol +equation very complicated don't how to + + align:start position:0% +equation very complicated don't how to + + + align:start position:0% +equation very complicated don't how to +do it so this actually problem even when + + align:start position:0% +do it so this actually problem even when + + + align:start position:0% +do it so this actually problem even when +I tried to do it took a very very detail + + align:start position:0% +I tried to do it took a very very detail + + + align:start position:0% +I tried to do it took a very very detail +a very hard calulation + + align:start position:0% +a very hard calulation + + + align:start position:0% +a very hard calulation +but when I just do statistic you can do + + align:start position:0% +but when I just do statistic you can do + + + align:start position:0% +but when I just do statistic you can do +your deration no for statistics energy + + align:start position:0% +your deration no for statistics energy + + + align:start position:0% +your deration no for statistics energy +balance current balance at the interface + + align:start position:0% +balance current balance at the interface + + + align:start position:0% +balance current balance at the interface +and what I found is that this is the + + align:start position:0% +and what I found is that this is the + + + align:start position:0% +and what I found is that this is the +electron temp on this side electr one + + align:start position:0% +electron temp on this side electr one + + + align:start position:0% +electron temp on this side electr one +and two just right at the interface it + + align:start position:0% +and two just right at the interface it + + + align:start position:0% +and two just right at the interface it +turn out that when I go down a step + + align:start position:0% +turn out that when I go down a step + + + align:start position:0% +turn out that when I go down a step +there is a amplification Factor this is + + align:start position:0% +there is a amplification Factor this is + + + align:start position:0% +there is a amplification Factor this is +the potential High + + align:start position:0% +the potential High + + + align:start position:0% +the potential High +and this is mean free pass so normally + + align:start position:0% +and this is mean free pass so normally + + + align:start position:0% +and this is mean free pass so normally +this is very small because me + + align:start position:0% +this is very small because me + + + align:start position:0% +this is very small because me +pass just temp drop with one that's + + align:start position:0% +pass just temp drop with one that's + + + align:start position:0% +pass just temp drop with one that's +very but what I saw what I saw + + align:start position:0% +very but what I saw what I saw + + + align:start position:0% +very but what I saw what I saw +interesting is if I have this structure + + align:start position:0% +interesting is if I have this structure + + + align:start position:0% +interesting is if I have this structure +I suddenly like the electron expand + + align:start position:0% +I suddenly like the electron expand + + + align:start position:0% +I suddenly like the electron expand +actually raises temperature or create a + + align:start position:0% +actually raises temperature or create a + + + align:start position:0% +actually raises temperature or create a +large temperature there's an + + align:start position:0% +large temperature there's an + + + align:start position:0% +large temperature there's an +amplification factor I + + align:start position:0% +amplification factor I + + + align:start position:0% +amplification factor I +canfy how much electron temperature draw + + align:start position:0% +canfy how much electron temperature draw + + + align:start position:0% +canfy how much electron temperature draw +at the interface so that's what I call + + align:start position:0% +at the interface so that's what I call + + + align:start position:0% +at the interface so that's what I call +potential amplifi on the other hand of + + align:start position:0% +potential amplifi on the other hand of + + + align:start position:0% +potential amplifi on the other hand of +my thisas structure same analysis didn't + + align:start position:0% +my thisas structure same analysis didn't + + + align:start position:0% +my thisas structure same analysis didn't +have + + align:start position:0% +have + + + align:start position:0% +have +that so so I follow up I said this is + + align:start position:0% +that so so I follow up I said this is + + + align:start position:0% +that so so I follow up I said this is +the board my statistic I did fir + + align:start position:0% +the board my statistic I did fir + + + align:start position:0% +the board my statistic I did fir +statistics and solve some equations and + + align:start position:0% +statistics and solve some equations and + + + align:start position:0% +statistics and solve some equations and +this is the equation this is the + + align:start position:0% +this is the equation this is the + + + align:start position:0% +this is the equation this is the +temperature the interface and you can + + align:start position:0% +temperature the interface and you can + + + align:start position:0% +temperature the interface and you can +say you can actually drive therm just + + align:start position:0% +say you can actually drive therm just + + + align:start position:0% +say you can actually drive therm just +with a tempure G you can grab electron + + align:start position:0% +with a tempure G you can grab electron + + + align:start position:0% +with a tempure G you can grab electron +and phon out + + align:start position:0% +and phon out + + + align:start position:0% +and phon out +of and this is the electron temperature + + align:start position:0% +of and this is the electron temperature + + + align:start position:0% +of and this is the electron temperature +jump at the interface but if you do the + + align:start position:0% +jump at the interface but if you do the + + + align:start position:0% +jump at the interface but if you do the +reverse structure there's no + + align:start position:0% +reverse structure there's no + + + align:start position:0% +reverse structure there's no +discontinuity in the interface so this + + align:start position:0% +discontinuity in the interface so this + + + align:start position:0% +discontinuity in the interface so this +this way s can help the efficiency of + + align:start position:0% +this way s can help the efficiency of + + + align:start position:0% +this way s can help the efficiency of +cooling but uh so far I have not like I + + align:start position:0% +cooling but uh so far I have not like I + + + align:start position:0% +cooling but uh so far I have not like I +said this is just a theory no + + align:start position:0% +said this is just a theory no + + + align:start position:0% +said this is just a theory no +experiment + + align:start position:0% +experiment + + + align:start position:0% +experiment +okay now I want to move on that's just + + align:start position:0% +okay now I want to move on that's just + + + align:start position:0% +okay now I want to move on that's just +a example sometimes it's interesting to + + align:start position:0% +a example sometimes it's interesting to + + + align:start position:0% +a example sometimes it's interesting to +TST and think whether you can have new + + align:start position:0% +TST and think whether you can have new + + + align:start position:0% +TST and think whether you can have new +ideas in this + + align:start position:0% +ideas in this + + + align:start position:0% +ideas in this +F now coming back now we talk about the + + align:start position:0% +F now coming back now we talk about the + + + align:start position:0% +F now coming back now we talk about the +the really the fs and this is the the + + align:start position:0% +the really the fs and this is the the + + + align:start position:0% +the really the fs and this is the the +injunction I just show + + align:start position:0% +injunction I just show + + + align:start position:0% +injunction I just show +and the saturation current sometimes + + align:start position:0% +and the saturation current sometimes + + + align:start position:0% +and the saturation current sometimes +people + + align:start position:0% +people + + + align:start position:0% +people +call + + align:start position:0% +call + + + align:start position:0% +call +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +detector and uh now uh we have a photon + + align:start position:0% +detector and uh now uh we have a photon + + + align:start position:0% +detector and uh now uh we have a photon +comes in gener electron over here so if + + align:start position:0% +comes in gener electron over here so if + + + align:start position:0% +comes in gener electron over here so if +the photon energy is larger than the + + align:start position:0% +the photon energy is larger than the + + + align:start position:0% +the photon energy is larger than the +bank Gap the bank Gap is always the same + + align:start position:0% +bank Gap the bank Gap is always the same + + + align:start position:0% +bank Gap the bank Gap is always the same +everywhere Bank Gap is the same so if + + align:start position:0% +everywhere Bank Gap is the same so if + + + align:start position:0% +everywhere Bank Gap is the same so if +the F energy is larger than b you + + align:start position:0% +the F energy is larger than b you + + + align:start position:0% +the F energy is larger than b you +generate lift the one electron from the + + align:start position:0% +generate lift the one electron from the + + + align:start position:0% +generate lift the one electron from the +valance band to the conduction B right + + align:start position:0% +valance band to the conduction B right + + + align:start position:0% +valance band to the conduction B right +and this could happen anywhere in the + + align:start position:0% +and this could happen anywhere in the + + + align:start position:0% +and this could happen anywhere in the +device that depends on how where Fon is + + align:start position:0% +device that depends on how where Fon is + + + align:start position:0% +device that depends on how where Fon is +abor we'll talk about that later right + + align:start position:0% +abor we'll talk about that later right + + + align:start position:0% +abor we'll talk about that later right +so what I'm drawing just okay my Fon + + align:start position:0% +so what I'm drawing just okay my Fon + + + align:start position:0% +so what I'm drawing just okay my Fon +happen to be absorbed within the space + + align:start position:0% +happen to be absorbed within the space + + + align:start position:0% +happen to be absorbed within the space +charge region then the + + align:start position:0% +charge region then the + + + align:start position:0% +charge region then the +electron is generated within space + + align:start position:0% +electron is generated within space + + + align:start position:0% +electron is generated within space +charge don't + + align:start position:0% +charge don't + + + align:start position:0% +charge don't +for right now what happens after this + + align:start position:0% +for right now what happens after this + + + align:start position:0% +for right now what happens after this +generation of course they were they have + + align:start position:0% +generation of course they were they have + + + align:start position:0% +generation of course they were they have +tendency Rec + + align:start position:0% +tendency Rec + + + align:start position:0% +tendency Rec +combine right and if you did Rec combine + + align:start position:0% +combine right and if you did Rec combine + + + align:start position:0% +combine right and if you did Rec combine +your photo cell is affiliate you don't + + align:start position:0% +your photo cell is affiliate you don't + + + align:start position:0% +your photo cell is affiliate you don't +want them to rec combine you want to + + align:start position:0% +want them to rec combine you want to + + + align:start position:0% +want them to rec combine you want to +separate + + align:start position:0% +separate + + + align:start position:0% +separate +it and now if Junction if in the space + + align:start position:0% +it and now if Junction if in the space + + + align:start position:0% +it and now if Junction if in the space +charge there's + + align:start position:0% +charge there's + + + align:start position:0% +charge there's +one because electron now there's a + + align:start position:0% +one because electron now there's a + + + align:start position:0% +one because electron now there's a +electric field inside so electron wants + + align:start position:0% +electric field inside so electron wants + + + align:start position:0% +electric field inside so electron wants +to + + align:start position:0% +to + + + align:start position:0% +to +go lower energy this way whole is the + + align:start position:0% +go lower energy this way whole is the + + + align:start position:0% +go lower energy this way whole is the +higher energy is the whole positive is + + align:start position:0% +higher energy is the whole positive is + + + align:start position:0% +higher energy is the whole positive is +the higher energy electron low say + + align:start position:0% +the higher energy electron low say + + + align:start position:0% +the higher energy electron low say +higher energy so go this way + + align:start position:0% + + + + align:start position:0% + +posi okay just go down the potential + + align:start position:0% +posi okay just go down the potential + + + align:start position:0% +posi okay just go down the potential +H this is the potential H this is + + align:start position:0% +H this is the potential H this is + + + align:start position:0% +H this is the potential H this is +potential + + align:start position:0% + + + + align:start position:0% + +for + + align:start position:0% +for + + + align:start position:0% +for +that's and this Lal tenden so now you + + align:start position:0% +that's and this Lal tenden so now you + + + align:start position:0% +that's and this Lal tenden so now you +got more electron this side then I say + + align:start position:0% +got more electron this side then I say + + + align:start position:0% +got more electron this side then I say +uh uh uh in normally equ no voltage + + align:start position:0% +uh uh uh in normally equ no voltage + + + align:start position:0% +uh uh uh in normally equ no voltage +right now you accumulate more electron + + align:start position:0% +right now you accumulate more electron + + + align:start position:0% +right now you accumulate more electron +this side accumulate more hole so you + + align:start position:0% +this side accumulate more hole so you + + + align:start position:0% +this side accumulate more hole so you +generate + + align:start position:0% +generate + + + align:start position:0% +generate +volt + + align:start position:0% +volt + + + align:start position:0% +volt +okay and once you generate voltage this + + align:start position:0% +okay and once you generate voltage this + + + align:start position:0% +okay and once you generate voltage this +voltage will drive your + + align:start position:0% +voltage will drive your + + + align:start position:0% +voltage will drive your +di right just like on this side you have + + align:start position:0% +di right just like on this side you have + + + align:start position:0% +di right just like on this side you have +volage difference you'll have a + + align:start position:0% + + + + align:start position:0% + +d so now if I have light comes in this + + align:start position:0% +d so now if I have light comes in this + + + align:start position:0% +d so now if I have light comes in this +is the current the electron ho current + + align:start position:0% +is the current the electron ho current + + + align:start position:0% +is the current the electron ho current +do the absorption of full time and now + + align:start position:0% +do the absorption of full time and now + + + align:start position:0% +do the absorption of full time and now +once I bu the voltage this is the + + align:start position:0% +once I bu the voltage this is the + + + align:start position:0% +once I bu the voltage this is the +current the forward that balance + + align:start position:0% +current the forward that balance + + + align:start position:0% +current the forward that balance +it right this is this is now when I have + + align:start position:0% +it right this is this is now when I have + + + align:start position:0% +it right this is this is now when I have +voltage I drive the DI and this is where + + align:start position:0% +voltage I drive the DI and this is where + + + align:start position:0% +voltage I drive the DI and this is where +I have electron generation the counter + + align:start position:0% +I have electron generation the counter + + + align:start position:0% +I have electron generation the counter +going this way and of course in a solar + + align:start position:0% +going this way and of course in a solar + + + align:start position:0% +going this way and of course in a solar +Cale I want to go this way I don't want + + align:start position:0% +Cale I want to go this way I don't want + + + align:start position:0% +Cale I want to go this way I don't want +I I want right I want this less than + + align:start position:0% + + + + align:start position:0% + +this okay so that's if you understand + + align:start position:0% +this okay so that's if you understand + + + align:start position:0% +this okay so that's if you understand +the DI that's + + align:start position:0% + + + + align:start position:0% + +a okay + + align:start position:0% +a okay + + + align:start position:0% +a okay +and you can so this one if you I want + + align:start position:0% +and you can so this one if you I want + + + align:start position:0% +and you can so this one if you I want +call the short C short circuit current + + align:start position:0% +call the short C short circuit current + + + align:start position:0% +call the short C short circuit current +if the Short Circuit the voltage + + align:start position:0% +if the Short Circuit the voltage + + + align:start position:0% +if the Short Circuit the voltage +difference is zero right you + + align:start position:0% +difference is zero right you + + + align:start position:0% +difference is zero right you +surely this there's no no resistance + + align:start position:0% +surely this there's no no resistance + + + align:start position:0% +surely this there's no no resistance +then this has to equal this no voltage + + align:start position:0% +then this has to equal this no voltage + + + align:start position:0% +then this has to equal this no voltage +want that's + + align:start position:0% +want that's + + + align:start position:0% +want that's +short short Circle short Circle both for + + align:start position:0% +short short Circle short Circle both for + + + align:start position:0% +short short Circle short Circle both for +zero that's your JL is your short + + align:start position:0% +zero that's your JL is your short + + + align:start position:0% +zero that's your JL is your short +CC + + align:start position:0% + + + + align:start position:0% + +right okay now I'm going to with that + + align:start position:0% +right okay now I'm going to with that + + + align:start position:0% +right okay now I'm going to with that +starting from there the rest is simple + + align:start position:0% +starting from there the rest is simple + + + align:start position:0% +starting from there the rest is simple +just MTH I can see what's my open + + align:start position:0% +just MTH I can see what's my open + + + align:start position:0% +just MTH I can see what's my open +circular voltage and my open circular + + align:start position:0% +circular voltage and my open circular + + + align:start position:0% +circular voltage and my open circular +voltage is just to say there's zero + + align:start position:0% +voltage is just to say there's zero + + + align:start position:0% +voltage is just to say there's zero +current so if I set this side zero I + + align:start position:0% +current so if I set this side zero I + + + align:start position:0% +current so if I set this side zero I +find what's the open circle voltage + + align:start position:0% +find what's the open circle voltage + + + align:start position:0% +find what's the open circle voltage +the open circuit voltage and you can + + align:start position:0% +the open circuit voltage and you can + + + align:start position:0% +the open circuit voltage and you can +further simplify because we know GS to + + align:start position:0% +further simplify because we know GS to + + + align:start position:0% +further simplify because we know GS to +that c right look at this called do + + align:start position:0% +that c right look at this called do + + + align:start position:0% +that c right look at this called do +current or saturation + + align:start position:0% +current or saturation + + + align:start position:0% +current or saturation +current and I the high open circular + + align:start position:0% +current and I the high open circular + + + align:start position:0% +current and I the high open circular +voltage what do you do smaller is better + + align:start position:0% +voltage what do you do smaller is better + + + align:start position:0% +voltage what do you do smaller is better +right J smaller is better you look at it + + align:start position:0% +right J smaller is better you look at it + + + align:start position:0% +right J smaller is better you look at it +smaller j i open + + align:start position:0% +smaller j i open + + + align:start position:0% +smaller j i open +circle + + align:start position:0% +circle + + + align:start position:0% +circle +right so JS power + + align:start position:0% +right so JS power + + + align:start position:0% +right so JS power +reculation time is longer JS + + align:start position:0% +reculation time is longer JS + + + align:start position:0% +reculation time is longer JS +smaller right so I don't want the + + align:start position:0% +smaller right so I don't want the + + + align:start position:0% +smaller right so I don't want the +recombination I want the long lifetime + + align:start position:0% +recombination I want the long lifetime + + + align:start position:0% +recombination I want the long lifetime +for the electron basically I want long + + align:start position:0% +for the electron basically I want long + + + align:start position:0% +for the electron basically I want long +life so I can exract + + align:start position:0% +life so I can exract + + + align:start position:0% +life so I can exract +out okay and you put like in the JSA + + align:start position:0% +out okay and you put like in the JSA + + + align:start position:0% +out okay and you put like in the JSA +related to all + + align:start position:0% +related to all + + + align:start position:0% +related to all +diffusivity comilation time wri down out + + align:start position:0% +diffusivity comilation time wri down out + + + align:start position:0% +diffusivity comilation time wri down out +here basically + + align:start position:0% +here basically + + + align:start position:0% +here basically +to the end you approxim drop this one + + align:start position:0% +to the end you approxim drop this one + + + align:start position:0% +to the end you approxim drop this one +that's what you get that's just + + align:start position:0% +that's what you get that's just + + + align:start position:0% +that's what you get that's just +matics on + + align:start position:0% +matics on + + + align:start position:0% +matics on +this now of course open circuit is + + align:start position:0% +this now of course open circuit is + + + align:start position:0% +this now of course open circuit is +useless because there's no power output + + align:start position:0% +useless because there's no power output + + + align:start position:0% +useless because there's no power output +in real operation we always have a load + + align:start position:0% +in real operation we always have a load + + + align:start position:0% +in real operation we always have a load +we have car flowing so uh when we have a + + align:start position:0% +we have car flowing so uh when we have a + + + align:start position:0% +we have car flowing so uh when we have a +car + + align:start position:0% +car + + + align:start position:0% +car +flowing uh uh uh Power and so but before + + align:start position:0% +flowing uh uh uh Power and so but before + + + align:start position:0% +flowing uh uh uh Power and so but before +I do that I want to show you if you draw + + align:start position:0% +I do that I want to show you if you draw + + + align:start position:0% +I do that I want to show you if you draw +this C voltage so this is your short + + align:start position:0% +this C voltage so this is your short + + + align:start position:0% +this C voltage so this is your short +circuit voltage Z short Circ + + align:start position:0% + + + + align:start position:0% + +current right when current is zero open + + align:start position:0% +current right when current is zero open + + + align:start position:0% +current right when current is zero open +Circ okay so it's more like you shifting + + align:start position:0% +Circ okay so it's more like you shifting + + + align:start position:0% +Circ okay so it's more like you shifting +di parall down this if if you don't have + + align:start position:0% +di parall down this if if you don't have + + + align:start position:0% +di parall down this if if you don't have +if you don't have a light + + align:start position:0% +if you don't have a light + + + align:start position:0% +if you don't have a light +illumination it's a DI equation right + + align:start position:0% +illumination it's a DI equation right + + + align:start position:0% +illumination it's a DI equation right +that's a diation you don't have this + + align:start position:0% +that's a diation you don't have this + + + align:start position:0% +that's a diation you don't have this +part sh that cve cve to + + align:start position:0% + + + + align:start position:0% + +the + + align:start position:0% + + + + align:start position:0% + +for + + align:start position:0% +for + + + align:start position:0% +for +okay and uh of course you can you can + + align:start position:0% +okay and uh of course you can you can + + + align:start position:0% +okay and uh of course you can you can +look at this the power output is voltage + + align:start position:0% +look at this the power output is voltage + + + align:start position:0% +look at this the power output is voltage +times current so + + align:start position:0% +times current so + + + align:start position:0% +times current so +somewhere your voltage that's this squ + + align:start position:0% +somewhere your voltage that's this squ + + + align:start position:0% +somewhere your voltage that's this squ +depends on which point your op + + align:start position:0% +depends on which point your op + + + align:start position:0% +depends on which point your op +you have + + align:start position:0% +you have + + + align:start position:0% +you have +maim and that's how you optimize you you + + align:start position:0% +maim and that's how you optimize you you + + + align:start position:0% +maim and that's how you optimize you you +change your load + + align:start position:0% +change your load + + + align:start position:0% +change your load +resistance okay so that you can control + + align:start position:0% +resistance okay so that you can control + + + align:start position:0% +resistance okay so that you can control +the current and the voltage by changing + + align:start position:0% +the current and the voltage by changing + + + align:start position:0% +the current and the voltage by changing +external L resistance so that's a low me + + align:start position:0% +external L resistance so that's a low me + + + align:start position:0% +external L resistance so that's a low me +you do that for ther elrics you do that + + align:start position:0% +you do that for ther elrics you do that + + + align:start position:0% +you do that for ther elrics you do that +for Sol cells or so you need to optimize + + align:start position:0% +for Sol cells or so you need to optimize + + + align:start position:0% +for Sol cells or so you need to optimize +so some people just design their circuit + + align:start position:0% +so some people just design their circuit + + + align:start position:0% +so some people just design their circuit +to optimize + + align:start position:0% + + + + align:start position:0% + +and very of people don't dra this way + + align:start position:0% +and very of people don't dra this way + + + align:start position:0% +and very of people don't dra this way +just reverse it for convenience so that + + align:start position:0% +just reverse it for convenience so that + + + align:start position:0% +just reverse it for convenience so that +will be another way to draw but that's + + align:start position:0% +will be another way to draw but that's + + + align:start position:0% +will be another way to draw but that's +the real one is actually to be on the + + align:start position:0% +the real one is actually to be on the + + + align:start position:0% +the real one is actually to be on the +side + + align:start position:0% +side + + + align:start position:0% +side +okay now we can uh go to see maximum + + align:start position:0% +okay now we can uh go to see maximum + + + align:start position:0% +okay now we can uh go to see maximum +power when the power output is maximize + + align:start position:0% +power when the power output is maximize + + + align:start position:0% +power when the power output is maximize +is the current times voltage that's the + + align:start position:0% +is the current times voltage that's the + + + align:start position:0% +is the current times voltage that's the +power right so you just take a + + align:start position:0% +power right so you just take a + + + align:start position:0% +power right so you just take a +derivative of your voltage and say when + + align:start position:0% +derivative of your voltage and say when + + + align:start position:0% +derivative of your voltage and say when +it's maximiz when you take + + align:start position:0% +it's maximiz when you take + + + align:start position:0% +it's maximiz when you take +derivative physically what you do is I'm + + align:start position:0% +derivative physically what you do is I'm + + + align:start position:0% +derivative physically what you do is I'm +changing my external load to find out + + align:start position:0% +changing my external load to find out + + + align:start position:0% +changing my external load to find out +where is the optimal volage so that + + align:start position:0% +where is the optimal volage so that + + + align:start position:0% +where is the optimal volage so that +power is + + align:start position:0% +power is + + + align:start position:0% +power is +maximized so so that if you take this + + align:start position:0% +maximized so so that if you take this + + + align:start position:0% +maximized so so that if you take this +derivative you'll find out where is the + + align:start position:0% +derivative you'll find out where is the + + + align:start position:0% +derivative you'll find out where is the +optimum current where is the optimal + + align:start position:0% +optimum current where is the optimal + + + align:start position:0% +optimum current where is the optimal +voltage + + align:start position:0% +voltage + + + align:start position:0% +voltage +okay and + + align:start position:0% +okay and + + + align:start position:0% +okay and +uh again see this is just mathematic + + align:start position:0% +uh again see this is just mathematic + + + align:start position:0% +uh again see this is just mathematic +detail not important but very often in + + align:start position:0% +detail not important but very often in + + + align:start position:0% +detail not important but very often in +the terminology people say what's your + + align:start position:0% +the terminology people say what's your + + + align:start position:0% +the terminology people say what's your +fail + + align:start position:0% +fail + + + align:start position:0% +fail +Factor what is that so this is the + + align:start position:0% +Factor what is that so this is the + + + align:start position:0% +Factor what is that so this is the +rectangular this is where you optimize + + align:start position:0% +rectangular this is where you optimize + + + align:start position:0% +rectangular this is where you optimize +you run your uh Optimum current voltage + + align:start position:0% +you run your uh Optimum current voltage + + + align:start position:0% +you run your uh Optimum current voltage +point right so that's the actual maximum + + align:start position:0% +point right so that's the actual maximum + + + align:start position:0% +point right so that's the actual maximum +power you you have and if you look at if + + align:start position:0% +power you you have and if you look at if + + + align:start position:0% +power you you have and if you look at if +you draw another + + align:start position:0% +you draw another + + + align:start position:0% +you draw another +rectangle where you draw the this set up + + align:start position:0% +rectangle where you draw the this set up + + + align:start position:0% +rectangle where you draw the this set up +uh the the uh uh short circular current + + align:start position:0% +uh the the uh uh short circular current + + + align:start position:0% +uh the the uh uh short circular current +and open Circ voltage you to another + + align:start position:0% +and open Circ voltage you to another + + + align:start position:0% +and open Circ voltage you to another +rectangle right this ratio of this Acra + + align:start position:0% +rectangle right this ratio of this Acra + + + align:start position:0% +rectangle right this ratio of this Acra +power divided by the outer rectangle + + align:start position:0% +power divided by the outer rectangle + + + align:start position:0% +power divided by the outer rectangle +that's your fi factor and you want to + + align:start position:0% +that's your fi factor and you want to + + + align:start position:0% +that's your fi factor and you want to +feel as much as you can you can say to + + align:start position:0% +feel as much as you can you can say to + + + align:start position:0% +feel as much as you can you can say to +get the maximum + + align:start position:0% +get the maximum + + + align:start position:0% +get the maximum +power okay + + align:start position:0% + + + + align:start position:0% + +now let's go to Source term Source this + + align:start position:0% +now let's go to Source term Source this + + + align:start position:0% +now let's go to Source term Source this +is a electron ho generation right so I + + align:start position:0% +is a electron ho generation right so I + + + align:start position:0% +is a electron ho generation right so I +have the radiation coming in only + + align:start position:0% +have the radiation coming in only + + + align:start position:0% +have the radiation coming in only +electrons photons with energy larger + + align:start position:0% +electrons photons with energy larger + + + align:start position:0% +electrons photons with energy larger +than Bap can generate + + align:start position:0% +than Bap can generate + + + align:start position:0% +than Bap can generate +electon so uh and also this let's + + align:start position:0% +electon so uh and also this let's + + + align:start position:0% +electon so uh and also this let's +suppose this is body that's Tre the sign + + align:start position:0% +suppose this is body that's Tre the sign + + + align:start position:0% +suppose this is body that's Tre the sign +as a + + align:start position:0% +as a + + + align:start position:0% +as a +body okay so the solar radiation come + + align:start position:0% +body okay so the solar radiation come + + + align:start position:0% +body okay so the solar radiation come +from s and this is the fraction of solar + + align:start position:0% +from s and this is the fraction of solar + + + align:start position:0% +from s and this is the fraction of solar +radiation actually so you have to look + + align:start position:0% +radiation actually so you have to look + + + align:start position:0% +radiation actually so you have to look +at the distance the fraction of solar + + align:start position:0% +at the distance the fraction of solar + + + align:start position:0% +at the distance the fraction of solar +radiation black body of the sign + + align:start position:0% +radiation black body of the sign + + + align:start position:0% +radiation black body of the sign +58 kin you know it's not just a close + + align:start position:0% +58 kin you know it's not just a close + + + align:start position:0% +58 kin you know it's not just a close +object + + align:start position:0% +object + + + align:start position:0% +object +500 of C right it's verify diver diluted + + align:start position:0% +500 of C right it's verify diver diluted + + + align:start position:0% +500 of C right it's verify diver diluted +so that's this + + align:start position:0% +so that's this + + + align:start position:0% +so that's this +fraction + + align:start position:0% + + + + align:start position:0% + +radiation but it's not the radiation + + align:start position:0% +radiation but it's not the radiation + + + align:start position:0% +radiation but it's not the radiation +intensity right it's the number of + + align:start position:0% +intensity right it's the number of + + + align:start position:0% +intensity right it's the number of +photons because each + + align:start position:0% +photons because each + + + align:start position:0% +photons because each +Photon generate one pair of + + align:start position:0% +Photon generate one pair of + + + align:start position:0% +Photon generate one pair of +electron so I'm looking at the energy + + align:start position:0% +electron so I'm looking at the energy + + + align:start position:0% +electron so I'm looking at the energy +because this is the energy that's the + + align:start position:0% +because this is the energy that's the + + + align:start position:0% +because this is the energy that's the +energy of per phot so I divide that + + align:start position:0% +energy of per phot so I divide that + + + align:start position:0% +energy of per phot so I divide that +that's the of photons + + align:start position:0% +that's the of photons + + + align:start position:0% +that's the of photons +coming it's not the flux of energy flux + + align:start position:0% +coming it's not the flux of energy flux + + + align:start position:0% +coming it's not the flux of energy flux +of photon coming + + align:start position:0% +of photon coming + + + align:start position:0% +of photon coming +toward and this is reflectivity I assume + + align:start position:0% +toward and this is reflectivity I assume + + + align:start position:0% +toward and this is reflectivity I assume +that a getting in the cell is absorb the + + align:start position:0% +that a getting in the cell is absorb the + + + align:start position:0% +that a getting in the cell is absorb the +gener electr that's of course + + align:start position:0% +gener electr that's of course + + + align:start position:0% +gener electr that's of course +idealization you got different losses + + align:start position:0% +idealization you got different losses + + + align:start position:0% +idealization you got different losses +this is best case and of course the max + + align:start position:0% +this is best case and of course the max + + + align:start position:0% +this is best case and of course the max +best there no refle that's + + align:start position:0% +best there no refle that's + + + align:start position:0% +best there no refle that's +one okay so this is a source + + align:start position:0% +one okay so this is a source + + + align:start position:0% +one okay so this is a source +term and uh the good thing is the source + + align:start position:0% +term and uh the good thing is the source + + + align:start position:0% +term and uh the good thing is the source +term depends on only the temperature if + + align:start position:0% +term depends on only the temperature if + + + align:start position:0% +term depends on only the temperature if +you idealize depends only on the + + align:start position:0% +you idealize depends only on the + + + align:start position:0% +you idealize depends only on the +temperature + + align:start position:0% +temperature + + + align:start position:0% +temperature +of the source + + align:start position:0% +of the source + + + align:start position:0% +of the source +right and when I come the + + align:start position:0% +right and when I come the + + + align:start position:0% +right and when I come the +efficiency this is the energy of the + + align:start position:0% +efficiency this is the energy of the + + + align:start position:0% +efficiency this is the energy of the +photon coming towards + + align:start position:0% +photon coming towards + + + align:start position:0% +photon coming towards +C and this is the power so of course I + + align:start position:0% +C and this is the power so of course I + + + align:start position:0% +C and this is the power so of course I +want to + + align:start position:0% +want to + + + align:start position:0% +want to +maximize efficiency everybody wants to + + align:start position:0% +maximize efficiency everybody wants to + + + align:start position:0% +maximize efficiency everybody wants to +maximiz and then the question is what's + + align:start position:0% +maximiz and then the question is what's + + + align:start position:0% +maximiz and then the question is what's +the maximum what's what how much you can + + align:start position:0% +the maximum what's what how much you can + + + align:start position:0% +the maximum what's what how much you can +get + + align:start position:0% +get + + + align:start position:0% +get +right second L first the solar cell is + + align:start position:0% +right second L first the solar cell is + + + align:start position:0% +right second L first the solar cell is +limited by second low col you can always + + align:start position:0% +limited by second low col you can always + + + align:start position:0% +limited by second low col you can always +say very safe the maximum efficiency you + + align:start position:0% +say very safe the maximum efficiency you + + + align:start position:0% +say very safe the maximum efficiency you +can get is a heat engine between sand + + align:start position:0% +can get is a heat engine between sand + + + align:start position:0% +can get is a heat engine between sand +and Earth so TC is 300 K T is the + + align:start position:0% +and Earth so TC is 300 K T is the + + + align:start position:0% +and Earth so TC is 300 K T is the +58 so that's that's an + + align:start position:0% +58 so that's that's an + + + align:start position:0% +58 so that's that's an +upper upper can't + + align:start position:0% +upper upper can't + + + align:start position:0% +upper upper can't +get yes I'm just curious what the way + + align:start position:0% +get yes I'm just curious what the way + + + align:start position:0% +get yes I'm just curious what the way +the picture you have on that slide so + + align:start position:0% +the picture you have on that slide so + + + align:start position:0% +the picture you have on that slide so +so it's it's actually inst on the P type + + align:start position:0% +so it's it's actually inst on the P type + + + align:start position:0% +so it's it's actually inst on the P type +and then only want to hit the the space + + align:start position:0% +and then only want to hit the the space + + + align:start position:0% +and then only want to hit the the space +Char + + align:start position:0% +Char + + + align:start position:0% +Char +reg so okay so the the full could be + + align:start position:0% +reg so okay so the the full could be + + + align:start position:0% +reg so okay so the the full could be +absorbed along the UN absorb here so + + align:start position:0% +absorbed along the UN absorb here so + + + align:start position:0% +absorbed along the UN absorb here so +some of them penetrate right yeah + + align:start position:0% +some of them penetrate right yeah + + + align:start position:0% +some of them penetrate right yeah +okay + + align:start position:0% +okay + + + align:start position:0% +okay +Char they have less probability go to + + align:start position:0% +Char they have less probability go to + + + align:start position:0% +Char they have less probability go to +the other side electron they diffuse you + + align:start position:0% +the other side electron they diffuse you + + + align:start position:0% +the other side electron they diffuse you +still diffuse there + + align:start position:0% +still diffuse there + + + align:start position:0% +still diffuse there +Fusion just to take a more the chance of + + align:start position:0% +Fusion just to take a more the chance of + + + align:start position:0% +Fusion just to take a more the chance of +getting there is less so that's why you + + align:start position:0% +getting there is less so that's why you + + + align:start position:0% +getting there is less so that's why you +want it that way and not + + align:start position:0% +want it that way and not + + + align:start position:0% +want it that way and not +like like you see how that is + + align:start position:0% +like like you see how that is + + + align:start position:0% +like like you see how that is +the + + align:start position:0% +the + + + align:start position:0% +the +like uhhuh so so so so you want to have + + align:start position:0% +like uhhuh so so so so you want to have + + + align:start position:0% +like uhhuh so so so so you want to have +a + + align:start position:0% +a + + + align:start position:0% +a +longer potential field Drive the + + align:start position:0% +longer potential field Drive the + + + align:start position:0% +longer potential field Drive the +actually use the field right I'm there's + + align:start position:0% +actually use the field right I'm there's + + + align:start position:0% +actually use the field right I'm there's +a picture right there the being thin and + + align:start position:0% +a picture right there the being thin and + + + align:start position:0% +a picture right there the being thin and +flat + + align:start position:0% +flat + + + align:start position:0% +flat +uh really th PN of course the good thing + + align:start position:0% +uh really th PN of course the good thing + + + align:start position:0% +uh really th PN of course the good thing +is your electrod is very + + align:start position:0% +is your electrod is very + + + align:start position:0% +is your electrod is very +close you can get to the two elect but + + align:start position:0% +close you can get to the two elect but + + + align:start position:0% +close you can get to the two elect but +your full not get AB so this is another + + align:start position:0% +your full not get AB so this is another + + + align:start position:0% +your full not get AB so this is another +that we going to talk that's your your + + align:start position:0% +that we going to talk that's your your + + + align:start position:0% +that we going to talk that's your your +battle your + + align:start position:0% +battle your + + + align:start position:0% +battle your +s you want + + align:start position:0% +s you want + + + align:start position:0% +s you want +get two you want to get the charge to + + align:start position:0% +get two you want to get the charge to + + + align:start position:0% +get two you want to get the charge to +the electr before they Rec combine one + + align:start position:0% +the electr before they Rec combine one + + + align:start position:0% +the electr before they Rec combine one +want Center the other one + + align:start position:0% +want Center the other one + + + align:start position:0% +want Center the other one +Zer this is essentially the same people + + align:start position:0% +Zer this is essentially the same people + + + align:start position:0% +Zer this is essentially the same people +trying to + + align:start position:0% +trying to + + + align:start position:0% +trying to +SW + + align:start position:0% +SW + + + align:start position:0% +SW +okay but the question we want to ask is + + align:start position:0% +okay but the question we want to ask is + + + align:start position:0% +okay but the question we want to ask is +what's the maximum + + align:start position:0% + + + + align:start position:0% + +possible okay what's the maximum + + align:start position:0% +possible okay what's the maximum + + + align:start position:0% +possible okay what's the maximum +possible and this one anybody to solar + + align:start position:0% +possible and this one anybody to solar + + + align:start position:0% +possible and this one anybody to solar +cell the first paper you read you should + + align:start position:0% +cell the first paper you read you should + + + align:start position:0% +cell the first paper you read you should +read is this Pap like shop and + + align:start position:0% + + + + align:start position:0% + +Sh okay that's what + + align:start position:0% +Sh okay that's what + + + align:start position:0% +Sh okay that's what +Sher limit uh we discuss the + + align:start position:0% +Sher limit uh we discuss the + + + align:start position:0% +Sher limit uh we discuss the +next and uh of course the real di right + + align:start position:0% +next and uh of course the real di right + + + align:start position:0% +next and uh of course the real di right +the real di is hard to get what's + + align:start position:0% +the real di is hard to get what's + + + align:start position:0% +the real di is hard to get what's +maximum the saturation depends on the + + align:start position:0% +maximum the saturation depends on the + + + align:start position:0% +maximum the saturation depends on the +material recation time if you + + align:start position:0% +material recation time if you + + + align:start position:0% +material recation time if you +you it's hard to get + + align:start position:0% +you it's hard to get + + + align:start position:0% +you it's hard to get +the and gen of chocolate I read a few + + align:start position:0% +the and gen of chocolate I read a few + + + align:start position:0% +the and gen of chocolate I read a few +people very very + + align:start position:0% +people very very + + + align:start position:0% +people very very +my and + + align:start position:0% + + + + align:start position:0% + +uh uh + + align:start position:0% + + + + align:start position:0% + +so this is what what what + + align:start position:0% +so this is what what what + + + align:start position:0% +so this is what what what +sh so if you think + + align:start position:0% +sh so if you think + + + align:start position:0% +sh so if you think +about pin Junction put under side right + + align:start position:0% +about pin Junction put under side right + + + align:start position:0% +about pin Junction put under side right +open + + align:start position:0% +open + + + align:start position:0% +open +circuit of course the solar radiation + + align:start position:0% +circuit of course the solar radiation + + + align:start position:0% +circuit of course the solar radiation +will create the electron HS continuously + + align:start position:0% +will create the electron HS continuously + + + align:start position:0% +will create the electron HS continuously +every Photon will gener electron here if + + align:start position:0% +every Photon will gener electron here if + + + align:start position:0% +every Photon will gener electron here if +there's no rec comination now defects + + align:start position:0% +there's no rec comination now defects + + + align:start position:0% +there's no rec comination now defects +Rec combine what happen you got to have + + align:start position:0% +Rec combine what happen you got to have + + + align:start position:0% +Rec combine what happen you got to have +AAL recombination process + + align:start position:0% +AAL recombination process + + + align:start position:0% +AAL recombination process +right spontaneous recation give about + + align:start position:0% +right spontaneous recation give about + + + align:start position:0% +right spontaneous recation give about +full so that's your maximum limit now + + align:start position:0% +full so that's your maximum limit now + + + align:start position:0% +full so that's your maximum limit now +other + + align:start position:0% +other + + + align:start position:0% +other +recombination only spontaneous + + align:start position:0% +recombination only spontaneous + + + align:start position:0% +recombination only spontaneous +recombination but what's that theous + + align:start position:0% +recombination but what's that theous + + + align:start position:0% +recombination but what's that theous +recation that okay and I'm really + + align:start position:0% +recation that okay and I'm really + + + align:start position:0% +recation that okay and I'm really +impressed I read a few paper this is + + align:start position:0% +impressed I read a few paper this is + + + align:start position:0% +impressed I read a few paper this is +where every time I I do this I have a + + align:start position:0% +where every time I I do this I have a + + + align:start position:0% +where every time I I do this I have a +place where I don't feel comfortable to + + align:start position:0% +place where I don't feel comfortable to + + + align:start position:0% +place where I don't feel comfortable to +tell you and I want to tell you because + + align:start position:0% +tell you and I want to tell you because + + + align:start position:0% +tell you and I want to tell you because +I want go to find + + align:start position:0% +I want go to find + + + align:start position:0% +I want go to find +out and this is not just I read + + align:start position:0% +out and this is not just I read + + + align:start position:0% +out and this is not just I read +yesterday I for many years I tried to + + align:start position:0% +yesterday I for many years I tried to + + + align:start position:0% +yesterday I for many years I tried to +understand this I still fully + + align:start position:0% +understand this I still fully + + + align:start position:0% +understand this I still fully +appr feel fully + + align:start position:0% +appr feel fully + + + align:start position:0% +appr feel fully +compl this is this expression where they + + align:start position:0% +compl this is this expression where they + + + align:start position:0% +compl this is this expression where they +came up and this is actually not in + + align:start position:0% +came up and this is actually not in + + + align:start position:0% +came up and this is actually not in +shock paper this is check paper and had + + align:start position:0% +shock paper this is check paper and had + + + align:start position:0% +shock paper this is check paper and had +another refer another by Ross and they + + align:start position:0% +another refer another by Ross and they + + + align:start position:0% +another refer another by Ross and they +all discuss different three different + + align:start position:0% +all discuss different three different + + + align:start position:0% +all discuss different three different +cherer three different way to write this + + align:start position:0% + + + + align:start position:0% + +expression and uh so when the P Junction + + align:start position:0% +expression and uh so when the P Junction + + + align:start position:0% +expression and uh so when the P Junction +has a voltage + + align:start position:0% +has a voltage + + + align:start position:0% +has a voltage +here and what's the uh the so we see the + + align:start position:0% +here and what's the uh the so we see the + + + align:start position:0% +here and what's the uh the so we see the +quom state + + align:start position:0% +quom state + + + align:start position:0% +quom state +the statistics right but what say what + + align:start position:0% +the statistics right but what say what + + + align:start position:0% +the statistics right but what say what +they the phons which oby + + align:start position:0% +they the phons which oby + + + align:start position:0% +they the phons which oby +Einstein in the + + align:start position:0% +Einstein in the + + + align:start position:0% +Einstein in the +injunction everything looks like except + + align:start position:0% +injunction everything looks like except + + + align:start position:0% +injunction everything looks like except +that he add + + align:start position:0% +that he add + + + align:start position:0% +that he add +e okay e is the you look at e is really + + align:start position:0% +e okay e is the you look at e is really + + + align:start position:0% +e okay e is the you look at e is really +the peral over here in N Tye p in this + + align:start position:0% +the peral over here in N Tye p in this + + + align:start position:0% +the peral over here in N Tye p in this +region that's the + + align:start position:0% +region that's the + + + align:start position:0% +region that's the +voltage it's adding this term that I + + align:start position:0% +voltage it's adding this term that I + + + align:start position:0% +voltage it's adding this term that I +just feel + + align:start position:0% +just feel + + + align:start position:0% +just feel +I can't comfortably dve it you can go to + + align:start position:0% +I can't comfortably dve it you can go to + + + align:start position:0% +I can't comfortably dve it you can go to +expand so each paper you start from + + align:start position:0% +expand so each paper you start from + + + align:start position:0% +expand so each paper you start from +different place and and I will encourage + + align:start position:0% +different place and and I will encourage + + + align:start position:0% +different place and and I will encourage +you to read and again if you have any + + align:start position:0% +you to read and again if you have any + + + align:start position:0% +you to read and again if you have any +idea to make my S + + align:start position:0% + + + + align:start position:0% + +comfortable because I I I for many years + + align:start position:0% +comfortable because I I I for many years + + + align:start position:0% +comfortable because I I I for many years +we actually looking into this see how we + + align:start position:0% +we actually looking into this see how we + + + align:start position:0% +we actually looking into this see how we +can really make comfortable D some um + + align:start position:0% +can really make comfortable D some um + + + align:start position:0% +can really make comfortable D some um +nearfield under nearfield where + + align:start position:0% +nearfield under nearfield where + + + align:start position:0% +nearfield under nearfield where +let's see so I can only just say take + + align:start position:0% +let's see so I can only just say take + + + align:start position:0% +let's see so I can only just say take +from here + + align:start position:0% + + + + align:start position:0% + +iier and the + + align:start position:0% +iier and the + + + align:start position:0% +iier and the +reculation + + align:start position:0% +reculation + + + align:start position:0% +reculation +reculation P Junction and if you do + + align:start position:0% +reculation P Junction and if you do + + + align:start position:0% +reculation P Junction and if you do +lasers or let down this is very + + align:start position:0% +lasers or let down this is very + + + align:start position:0% +lasers or let down this is very +important this is very of people + + align:start position:0% +important this is very of people + + + align:start position:0% +important this is very of people +St okay but I Haven seen the one that + + align:start position:0% +St okay but I Haven seen the one that + + + align:start position:0% +St okay but I Haven seen the one that +really to thody + + align:start position:0% +really to thody + + + align:start position:0% +really to thody +very + + align:start position:0% +very + + + align:start position:0% +very +easy so that's promote how + + align:start position:0% +easy so that's promote how + + + align:start position:0% +easy so that's promote how +mechanically promote how many to you + + align:start position:0% +mechanically promote how many to you + + + align:start position:0% +mechanically promote how many to you +have + + align:start position:0% + + + + align:start position:0% + +and okay now starting from + + align:start position:0% +and okay now starting from + + + align:start position:0% +and okay now starting from +here you can deride what du this + + align:start position:0% +here you can deride what du this + + + align:start position:0% +here you can deride what du this +recombination now you have a voltage the + + align:start position:0% +recombination now you have a voltage the + + + align:start position:0% +recombination now you have a voltage the +arbitrary voltage what recombination + + align:start position:0% +arbitrary voltage what recombination + + + align:start position:0% +arbitrary voltage what recombination +part so you just integrate again uh from + + align:start position:0% +part so you just integrate again uh from + + + align:start position:0% +part so you just integrate again uh from +the band Gap to any energy and if you do + + align:start position:0% +the band Gap to any energy and if you do + + + align:start position:0% +the band Gap to any energy and if you do +static you just neglect one factor one + + align:start position:0% +static you just neglect one factor one + + + align:start position:0% +static you just neglect one factor one +and this is the uh L I didn't write the + + align:start position:0% +and this is the uh L I didn't write the + + + align:start position:0% +and this is the uh L I didn't write the +equation copy from paper and this is + + align:start position:0% +equation copy from paper and this is + + + align:start position:0% +equation copy from paper and this is +angular integration so that's + + align:start position:0% +angular integration so that's + + + align:start position:0% +angular integration so that's +essentially the full density of + + align:start position:0% +essentially the full density of + + + align:start position:0% +essentially the full density of +States inside + + align:start position:0% +States inside + + + align:start position:0% +States inside +the so + + align:start position:0% +the so + + + align:start position:0% +the so +it's statistics integrated + + align:start position:0% +it's statistics integrated + + + align:start position:0% +it's statistics integrated +kind so this is the spontaneous emission + + align:start position:0% +kind so this is the spontaneous emission + + + align:start position:0% +kind so this is the spontaneous emission +due to the current that can create + + align:start position:0% + + + + align:start position:0% + +at and is very similar to what we had + + align:start position:0% +at and is very similar to what we had + + + align:start position:0% +at and is very similar to what we had +before except a is longer that due to if + + align:start position:0% +before except a is longer that due to if + + + align:start position:0% +before except a is longer that due to if +you look at the DI a right this is the a + + align:start position:0% +you look at the DI a right this is the a + + + align:start position:0% +you look at the DI a right this is the a +for the + + align:start position:0% +for the + + + align:start position:0% +for the +DI that's determined by action mat + + align:start position:0% +DI that's determined by action mat + + + align:start position:0% +DI that's determined by action mat +recation and then here + + align:start position:0% +recation and then here + + + align:start position:0% +recation and then here +here theity is no this is really just DC + + align:start position:0% +here theity is no this is really just DC + + + align:start position:0% +here theity is no this is really just DC +constant refractive + + align:start position:0% +constant refractive + + + align:start position:0% +constant refractive +index B on material so this is the + + align:start position:0% +index B on material so this is the + + + align:start position:0% +index B on material so this is the +maximum you can have the best you can + + align:start position:0% +maximum you can have the best you can + + + align:start position:0% +maximum you can have the best you can +have as re recombination no no other + + align:start position:0% +have as re recombination no no other + + + align:start position:0% +have as re recombination no no other +defect so because of that it's free of + + align:start position:0% +defect so because of that it's free of + + + align:start position:0% +defect so because of that it's free of +any material so now you can derive + + align:start position:0% +any material so now you can derive + + + align:start position:0% +any material so now you can derive +the but in see of one material that's + + align:start position:0% +the but in see of one material that's + + + align:start position:0% +the but in see of one material that's +the EG right + + align:start position:0% +the EG right + + + align:start position:0% +the EG right +this is the only other material you have + + align:start position:0% +this is the only other material you have + + + align:start position:0% +this is the only other material you have +but while I talk you can also say ah how + + align:start position:0% +but while I talk you can also say ah how + + + align:start position:0% +but while I talk you can also say ah how +about the photonic crystal inside + + align:start position:0% +about the photonic crystal inside + + + align:start position:0% +about the photonic crystal inside +photonic Crystal this Factor we + + align:start position:0% +photonic Crystal this Factor we + + + align:start position:0% +photonic Crystal this Factor we +check + + align:start position:0% + + + + align:start position:0% + +spontaneous and maybe you got a + + align:start position:0% + + + + align:start position:0% + +different so now I have translated that + + align:start position:0% +different so now I have translated that + + + align:start position:0% +different so now I have translated that +if you look at the term this is the C + + align:start position:0% +if you look at the term this is the C + + + align:start position:0% +if you look at the term this is the C +ter the dial equation right one is the + + align:start position:0% +ter the dial equation right one is the + + + align:start position:0% +ter the dial equation right one is the +dial C the other is the full generator C + + align:start position:0% +dial C the other is the full generator C + + + align:start position:0% +dial C the other is the full generator C +this is the phon gener C in the best + + align:start position:0% +this is the phon gener C in the best + + + align:start position:0% +this is the phon gener C in the best +case this is one so I put in the best + + align:start position:0% +case this is one so I put in the best + + + align:start position:0% +case this is one so I put in the best +scenario and the AR is independent + + align:start position:0% +scenario and the AR is independent + + + align:start position:0% +scenario and the AR is independent +material except the b g only the B Gap + + align:start position:0% +material except the b g only the B Gap + + + align:start position:0% +material except the b g only the B Gap +so that's where shly to derive what's + + align:start position:0% +so that's where shly to derive what's + + + align:start position:0% +so that's where shly to derive what's +the + + align:start position:0% +the + + + align:start position:0% +the +m and this is the U the curve not cop + + align:start position:0% +m and this is the U the curve not cop + + + align:start position:0% +m and this is the U the curve not cop +from Chate + + align:start position:0% +from Chate + + + align:start position:0% +from Chate +paper and using this comination + + align:start position:0% +paper and using this comination + + + align:start position:0% +paper and using this comination +current + + align:start position:0% +current + + + align:start position:0% +current +generated this + + align:start position:0% +generated this + + + align:start position:0% +generated this +the + + align:start position:0% +the + + + align:start position:0% +the +the gener and the rest just we did + + align:start position:0% +the gener and the rest just we did + + + align:start position:0% +the gener and the rest just we did +before find out what's the maximum power + + align:start position:0% +before find out what's the maximum power + + + align:start position:0% +before find out what's the maximum power +and what's + + align:start position:0% +and what's + + + align:start position:0% +and what's +maximum and this is what uh uh + + align:start position:0% +maximum and this is what uh uh + + + align:start position:0% +maximum and this is what uh uh +calculated and here C is the + + align:start position:0% +calculated and here C is the + + + align:start position:0% +calculated and here C is the +concentration what concentration op + + align:start position:0% +concentration what concentration op + + + align:start position:0% +concentration what concentration op +concentration what what it does change + + align:start position:0% +concentration what what it does change + + + align:start position:0% +concentration what what it does change +JL right if you concentrate more you + + align:start position:0% +JL right if you concentrate more you + + + align:start position:0% +JL right if you concentrate more you +generate more un pair for un body so + + align:start position:0% +generate more un pair for un body so + + + align:start position:0% +generate more un pair for un body so +this is if you concentrate you get this + + align:start position:0% +this is if you concentrate you get this + + + align:start position:0% +this is if you concentrate you get this +larger you get a larger open circuit + + align:start position:0% +larger you get a larger open circuit + + + align:start position:0% +larger you get a larger open circuit +voltage so concentration actually can + + align:start position:0% +voltage so concentration actually can + + + align:start position:0% +voltage so concentration actually can +help you increase + + align:start position:0% +help you increase + + + align:start position:0% +help you increase +efficiency okay so uh not too much + + align:start position:0% +efficiency okay so uh not too much + + + align:start position:0% +efficiency okay so uh not too much +increase but + + align:start position:0% +increase but + + + align:start position:0% +increase but +and what's interesting you look at it + + align:start position:0% +and what's interesting you look at it + + + align:start position:0% +and what's interesting you look at it +under one + + align:start position:0% +under one + + + align:start position:0% +under one +condition right where is the op + + align:start position:0% +condition right where is the op + + + align:start position:0% +condition right where is the op +Bank + + align:start position:0% + + + + align:start position:0% + +1.5 look at Material where is about + + align:start position:0% +1.5 look at Material where is about + + + align:start position:0% +1.5 look at Material where is about +what's that + + align:start position:0% + + + + align:start position:0% + +material + + align:start position:0% +material + + + align:start position:0% +material +1.1 not too far from the out so this is + + align:start position:0% +1.1 not too far from the out so this is + + + align:start position:0% +1.1 not too far from the out so this is +about + + align:start position:0% + + + + align:start position:0% + +okay so that c you if you build the + + align:start position:0% +okay so that c you if you build the + + + align:start position:0% +okay so that c you if you build the +same this is about best you can + + align:start position:0% + + + + align:start position:0% + +do uh you mean the uh how many phon + + align:start position:0% + + + + align:start position:0% + +you + + align:start position:0% + + + + align:start position:0% + +have what happens for + + align:start position:0% +have what happens for + + + align:start position:0% +have what happens for +examp they + + align:start position:0% +examp they + + + align:start position:0% +examp they +absal energy + + align:start position:0% + + + + align:start position:0% + +as64 right exactly so so this is a this + + align:start position:0% +as64 right exactly so so this is a this + + + align:start position:0% +as64 right exactly so so this is a this +is black body C right this is your your + + align:start position:0% +is black body C right this is your your + + + align:start position:0% +is black body C right this is your your +B Gap somewhere here okay and uh really + + align:start position:0% +B Gap somewhere here okay and uh really + + + align:start position:0% +B Gap somewhere here okay and uh really +what's use for energy because this above + + align:start position:0% +what's use for energy because this above + + + align:start position:0% +what's use for energy because this above +the Gap energy is lost so if I look at + + align:start position:0% +the Gap energy is lost so if I look at + + + align:start position:0% +the Gap energy is lost so if I look at +this is the B structure if I haveon + + align:start position:0% +this is the B structure if I haveon + + + align:start position:0% +this is the B structure if I haveon +generate electron this way this energ + + align:start position:0% +generate electron this way this energ + + + align:start position:0% +generate electron this way this energ +electron relax bottom very fast okay + + align:start position:0% +electron relax bottom very fast okay + + + align:start position:0% +electron relax bottom very fast okay +whole relax to here very fast so this is + + align:start position:0% +whole relax to here very fast so this is + + + align:start position:0% +whole relax to here very fast so this is +a + + align:start position:0% +a + + + align:start position:0% +a +heat and in fact people have been + + align:start position:0% +heat and in fact people have been + + + align:start position:0% +heat and in fact people have been +seizing how the electron C if you can + + align:start position:0% +seizing how the electron C if you can + + + align:start position:0% +seizing how the electron C if you can +extract this electron out with this kind + + align:start position:0% +extract this electron out with this kind + + + align:start position:0% +extract this electron out with this kind +of energy that's how ELR question how + + align:start position:0% +of energy that's how ELR question how + + + align:start position:0% +of energy that's how ELR question how +you get it out before relax this is + + align:start position:0% +you get it out before relax this is + + + align:start position:0% +you get it out before relax this is +about P second so P second is very fast + + align:start position:0% +about P second so P second is very fast + + + align:start position:0% +about P second so P second is very fast +if you times 10 time diffusivity just + + align:start position:0% +if you times 10 time diffusivity just + + + align:start position:0% +if you times 10 time diffusivity just +travel n or n just have no way to + + align:start position:0% + + + + align:start position:0% + +get if you have good ideas that's + + align:start position:0% +get if you have good ideas that's + + + align:start position:0% +get if you have good ideas that's +something people thinking for + + align:start position:0% + + + + align:start position:0% + +okay so that's a simple Junction Maxim + + align:start position:0% +okay so that's a simple Junction Maxim + + + align:start position:0% +okay so that's a simple Junction Maxim +you can + + align:start position:0% +you can + + + align:start position:0% +you can +get and exactly on this + + align:start position:0% +get and exactly on this + + + align:start position:0% +get and exactly on this +issue right how about we do multi- + + align:start position:0% +issue right how about we do multi- + + + align:start position:0% +issue right how about we do multi- +Junction right one C so multi- Junction + + align:start position:0% +Junction right one C so multi- Junction + + + align:start position:0% +Junction right one C so multi- Junction +like show here the first one absorb blue + + align:start position:0% +like show here the first one absorb blue + + + align:start position:0% +like show here the first one absorb blue +so larger B Gap the top most layer + + align:start position:0% +so larger B Gap the top most layer + + + align:start position:0% +so larger B Gap the top most layer +and the lower longer we lower energy can + + align:start position:0% +and the lower longer we lower energy can + + + align:start position:0% +and the lower longer we lower energy can +transmit so get absorbed second and get + + align:start position:0% +transmit so get absorbed second and get + + + align:start position:0% +transmit so get absorbed second and get +also third that's the idea and of course + + align:start position:0% +also third that's the idea and of course + + + align:start position:0% +also third that's the idea and of course +you can see with this + + align:start position:0% +you can see with this + + + align:start position:0% +you can see with this +stacking each car each one generate a + + align:start position:0% +stacking each car each one generate a + + + align:start position:0% +stacking each car each one generate a +current + + align:start position:0% +current + + + align:start position:0% +current +right if you look at this the case your + + align:start position:0% +right if you look at this the case your + + + align:start position:0% +right if you look at this the case your +current has to be continuous because you + + align:start position:0% +current has to be continuous because you + + + align:start position:0% +current has to be continuous because you +put the on top on bottom so this C has + + align:start position:0% +put the on top on bottom so this C has + + + align:start position:0% +put the on top on bottom so this C has +to generate the same on the C that's a + + align:start position:0% +to generate the same on the C that's a + + + align:start position:0% +to generate the same on the C that's a +design right + + align:start position:0% +design right + + + align:start position:0% +design right +almost right and uh uh but people have + + align:start position:0% +almost right and uh uh but people have + + + align:start position:0% +almost right and uh uh but people have +done that it's a material liare and + + align:start position:0% +done that it's a material liare and + + + align:start position:0% +done that it's a material liare and +design + + align:start position:0% +design + + + align:start position:0% +design +liare and design in a sense you have to + + align:start position:0% +liare and design in a sense you have to + + + align:start position:0% +liare and design in a sense you have to +get a c match so the electron go come + + align:start position:0% +get a c match so the electron go come + + + align:start position:0% +get a c match so the electron go come +from the top layer has to go to the hole + + align:start position:0% +from the top layer has to go to the hole + + + align:start position:0% +from the top layer has to go to the hole +of the next layer or hole of the top + + align:start position:0% +of the next layer or hole of the top + + + align:start position:0% +of the next layer or hole of the top +layer has to merge with + + align:start position:0% +layer has to merge with + + + align:start position:0% +layer has to merge with +theayer right Cent is + + align:start position:0% +theayer right Cent is + + + align:start position:0% +theayer right Cent is +continuous and and uh you have to grou + + align:start position:0% +continuous and and uh you have to grou + + + align:start position:0% +continuous and and uh you have to grou +different materials because + + align:start position:0% +different materials because + + + align:start position:0% +different materials because +recompilation is a killer right so so + + align:start position:0% +recompilation is a killer right so so + + + align:start position:0% +recompilation is a killer right so so +that's why people do + + align:start position:0% +that's why people do + + + align:start position:0% +that's why people do +Mo match you generate defect you + + align:start position:0% +Mo match you generate defect you + + + align:start position:0% +Mo match you generate defect you +generate + + align:start position:0% +generate + + + align:start position:0% +generate +dislocations this were just centers for + + align:start position:0% +dislocations this were just centers for + + + align:start position:0% +dislocations this were just centers for +the + + align:start position:0% +the + + + align:start position:0% +the +recombination and then you kill that you + + align:start position:0% +recombination and then you kill that you + + + align:start position:0% +recombination and then you kill that you +kill the electrons before you take + + align:start position:0% +kill the electrons before you take + + + align:start position:0% +kill the electrons before you take +out so to gr this material people + + align:start position:0% +out so to gr this material people + + + align:start position:0% +out so to gr this material people +done like a spectral dial spectral of + + align:start position:0% +done like a spectral dial spectral of + + + align:start position:0% +done like a spectral dial spectral of +down lab they were doing laser before + + align:start position:0% +down lab they were doing laser before + + + align:start position:0% +down lab they were doing laser before +now they're doing probably 40 41% for + + align:start position:0% +now they're doing probably 40 41% for + + + align:start position:0% +now they're doing probably 40 41% for +sales people + + align:start position:0% +sales people + + + align:start position:0% +sales people +Junction Junctions that R + + align:start position:0% + + + + align:start position:0% + +that's and so this is I got one from + + align:start position:0% +that's and so this is I got one from + + + align:start position:0% +that's and so this is I got one from +internet I think give some IDE City real + + align:start position:0% +internet I think give some IDE City real + + + align:start position:0% +internet I think give some IDE City real +15% to + + align:start position:0% +15% to + + + align:start position:0% +15% to +18% our + + align:start position:0% +18% our + + + align:start position:0% +18% our +skill and then uh + + align:start position:0% + + + + align:start position:0% + +30% and now this is a + + align:start position:0% + + + + align:start position:0% + +junction4 or matal you have to look at + + align:start position:0% +junction4 or matal you have to look at + + + align:start position:0% +junction4 or matal you have to look at +matal C and you can grow so you have to + + align:start position:0% +matal C and you can grow so you have to + + + align:start position:0% +matal C and you can grow so you have to +look at both material and band Gap + + align:start position:0% + + + + align:start position:0% + +device + + align:start position:0% +device + + + align:start position:0% +device +and how + + align:start position:0% + + + + align:start position:0% + +so this is the paper it shows 72% if you + + align:start position:0% +so this is the paper it shows 72% if you + + + align:start position:0% +so this is the paper it shows 72% if you +got + + align:start position:0% +got + + + align:start position:0% +got +36 say m spectral each 36 stage okay and + + align:start position:0% +36 say m spectral each 36 stage okay and + + + align:start position:0% +36 say m spectral each 36 stage okay and +if you have a infinite stage the Ser is + + align:start position:0% +if you have a infinite stage the Ser is + + + align:start position:0% +if you have a infinite stage the Ser is +about + + align:start position:0% +about + + + align:start position:0% +about +86% that's the + + align:start position:0% +86% that's the + + + align:start position:0% +86% that's the +best around + + align:start position:0% + + + + align:start position:0% + +86% c lower than the col + + align:start position:0% +86% c lower than the col + + + align:start position:0% +86% c lower than the col + + align:start position:0% + + + align:start position:0% +30000 that's + + align:start position:0% +30000 that's + + + align:start position:0% +30000 that's +L + + align:start position:0% + + + + align:start position:0% + + + align:start position:0% + + + + align:start position:0% + +okay so that's + + align:start position:0% +okay so that's + + + align:start position:0% +okay so that's +the what people can do say Theory say + + align:start position:0% +the what people can do say Theory say + + + align:start position:0% +the what people can do say Theory say +now you look at practice in the lab this + + align:start position:0% +now you look at practice in the lab this + + + align:start position:0% +now you look at practice in the lab this +is the best in the lab it's not best + + align:start position:0% +is the best in the lab it's not best + + + align:start position:0% +is the best in the lab it's not best +deploy C where is the first time + + align:start position:0% +deploy C where is the first time + + + align:start position:0% +deploy C where is the first time +C uh + + align:start position:0% +C uh + + + align:start position:0% +C uh +silicon yeah here this + + align:start position:0% +silicon yeah here this + + + align:start position:0% +silicon yeah here this +isic function right best is about + + align:start position:0% +isic function right best is about + + + align:start position:0% +isic function right best is about +56% I remember I this + + align:start position:0% + + + + align:start position:0% + +is probably the biggest + + align:start position:0% + + + + align:start position:0% + +guy told me about + + align:start position:0% + + + + align:start position:0% + +27 that's remember shop reisor gives you + + align:start position:0% +27 that's remember shop reisor gives you + + + align:start position:0% +27 that's remember shop reisor gives you + + align:start position:0% + + + align:start position:0% +31% so do really + + align:start position:0% +31% so do really + + + align:start position:0% +31% so do really +well + + align:start position:0% +well + + + align:start position:0% +well +that + + align:start position:0% +that + + + align:start position:0% +that +amazing and uh uh also so that's why all + + align:start position:0% +amazing and uh uh also so that's why all + + + align:start position:0% +amazing and uh uh also so that's why all +your your potential is also Li that's + + align:start position:0% +your your potential is also Li that's + + + align:start position:0% +your your potential is also Li that's +the best you do right but in fact you + + align:start position:0% +the best you do right but in fact you + + + align:start position:0% +the best you do right but in fact you +you can really do that at low cost I + + align:start position:0% +you can really do that at low cost I + + + align:start position:0% +you can really do that at low cost I +think your problem + + align:start position:0% +think your problem + + + align:start position:0% +think your problem +solve you can always work in + + align:start position:0% + + + + align:start position:0% + +betterine is only + + align:start position:0% + + + + align:start position:0% + +of course + + align:start position:0% + + + + align:start position:0% + +power and so the best multi- + + align:start position:0% +power and so the best multi- + + + align:start position:0% +power and so the best multi- +Junction right + + align:start position:0% +Junction right + + + align:start position:0% +Junction right +spe uh here is less than but I think + + align:start position:0% +spe uh here is less than but I think + + + align:start position:0% +spe uh here is less than but I think +that now the best about + + align:start position:0% + + + + align:start position:0% + +41% + + align:start position:0% +41% + + + align:start position:0% +41% +okay and uh this is a + + align:start position:0% +okay and uh this is a + + + align:start position:0% +okay and uh this is a +multi this is a single multi + + align:start position:0% +multi this is a single multi + + + align:start position:0% +multi this is a single multi +and let's look at a + + align:start position:0% + + + + align:start position:0% + +mic okay it's well the real world is + + align:start position:0% +mic okay it's well the real world is + + + align:start position:0% +mic okay it's well the real world is +about 6 to 8% + + align:start position:0% +about 6 to 8% + + + align:start position:0% +about 6 to 8% +deploy in the lab about 12% that's + + align:start position:0% +deploy in the lab about 12% that's + + + align:start position:0% +deploy in the lab about 12% that's +a + + align:start position:0% + + + + align:start position:0% + +not and this is a uh say coer eum uh the + + align:start position:0% +not and this is a uh say coer eum uh the + + + align:start position:0% +not and this is a uh say coer eum uh the +six coer + + align:start position:0% + + + + align:start position:0% + +medum and so the best is about + + align:start position:0% + + + + align:start position:0% + +19% + + align:start position:0% + + + + align:start position:0% + +and and said is dark because most people + + align:start position:0% +and and said is dark because most people + + + align:start position:0% +and and said is dark because most people +talk about 6 before and now is probably + + align:start position:0% +talk about 6 before and now is probably + + + align:start position:0% +talk about 6 before and now is probably +best most profitable + + align:start position:0% +best most profitable + + + align:start position:0% +best most profitable +compy and near SE I think + + align:start position:0% +compy and near SE I think + + + align:start position:0% +compy and near SE I think +from Lab to real + + align:start position:0% + + + + align:start position:0% + +production and then uh uh this one is + + align:start position:0% +production and then uh uh this one is + + + align:start position:0% +production and then uh uh this one is +the I think + + align:start position:0% +the I think + + + align:start position:0% +the I think +organic and then there's a + + align:start position:0% + + + + align:start position:0% + +th + + align:start position:0% + + + + align:start position:0% + +that's so this will give to work not the + + align:start position:0% +that's so this will give to work not the + + + align:start position:0% +that's so this will give to work not the +most of years but pretty + + align:start position:0% +most of years but pretty + + + align:start position:0% +most of years but pretty +close what are the problems right + + align:start position:0% +close what are the problems right + + + align:start position:0% +close what are the problems right +mention one for solar cell the L one + + align:start position:0% +mention one for solar cell the L one + + + align:start position:0% +mention one for solar cell the L one +device + + align:start position:0% +device + + + align:start position:0% +device +that's myar device very sensitive to + + align:start position:0% +that's myar device very sensitive to + + + align:start position:0% +that's myar device very sensitive to +recombination so what are the creation + + align:start position:0% +recombination so what are the creation + + + align:start position:0% +recombination so what are the creation +what are this uh what are the reason for + + align:start position:0% + + + + align:start position:0% + +recombination impurities + + align:start position:0% + + + + align:start position:0% + +deep in the bank deep level those + + align:start position:0% +deep in the bank deep level those + + + align:start position:0% +deep in the bank deep level those +areation bombs attack + + align:start position:0% +areation bombs attack + + + align:start position:0% +areation bombs attack +sh + + align:start position:0% +sh + + + align:start position:0% +sh +right and uh bom where you got a lot + + align:start position:0% +right and uh bom where you got a lot + + + align:start position:0% +right and uh bom where you got a lot +of those regions where + + align:start position:0% + + + + align:start position:0% + +recation and that's why people purify + + align:start position:0% +recation and that's why people purify + + + align:start position:0% +recation and that's why people purify +cic CH cic example + + align:start position:0% +cic CH cic example + + + align:start position:0% +cic CH cic example +G is about $2 per per gr per kilogram + + align:start position:0% +G is about $2 per per gr per kilogram + + + align:start position:0% +G is about $2 per per gr per kilogram +C if you want to make a solar Cale you + + align:start position:0% +C if you want to make a solar Cale you + + + align:start position:0% +C if you want to make a solar Cale you +can you re crystalize purify and got to + + align:start position:0% +can you re crystalize purify and got to + + + align:start position:0% +can you re crystalize purify and got to +$40 and of course during process + + align:start position:0% +$40 and of course during process + + + align:start position:0% +$40 and of course during process +lot + + align:start position:0% +lot + + + align:start position:0% +lot +out and in fact that last year before + + align:start position:0% +out and in fact that last year before + + + align:start position:0% +out and in fact that last year before +the market crashed everybody was on 6 + + align:start position:0% +the market crashed everybody was on 6 + + + align:start position:0% +the market crashed everybody was on 6 +so the C of short and that's got + + align:start position:0% + + + + align:start position:0% + +$40 okay so that's a one that's say + + align:start position:0% +$40 okay so that's a one that's say + + + align:start position:0% +$40 okay so that's a one that's say +minity device is and in that sense + + align:start position:0% +minity device is and in that sense + + + align:start position:0% +minity device is and in that sense +IC good because it's majority character + + align:start position:0% +IC good because it's majority character + + + align:start position:0% +IC good because it's majority character +doesn't + + align:start position:0% + + + + align:start position:0% + +have and the other problem this is + + align:start position:0% +have and the other problem this is + + + align:start position:0% +have and the other problem this is +AB in fact this is to me I say okay full + + align:start position:0% +AB in fact this is to me I say okay full + + + align:start position:0% +AB in fact this is to me I say okay full +company First Step + + align:start position:0% +company First Step + + + align:start position:0% +company First Step +absorb second step is charge where it + + align:start position:0% +absorb second step is charge where it + + + align:start position:0% +absorb second step is charge where it +goes so this is really the first step + + align:start position:0% +goes so this is really the first step + + + align:start position:0% +goes so this is really the first step +and look at word goes right of course + + align:start position:0% +and look at word goes right of course + + + align:start position:0% +and look at word goes right of course +the interface reflection you don't want + + align:start position:0% +the interface reflection you don't want + + + align:start position:0% +the interface reflection you don't want +refle minimize that verse C Surface + + align:start position:0% +refle minimize that verse C Surface + + + align:start position:0% +refle minimize that verse C Surface +equipment and once you get a input + + align:start position:0% +equipment and once you get a input + + + align:start position:0% +equipment and once you get a input +material you don't have almost no other + + align:start position:0% +material you don't have almost no other + + + align:start position:0% +material you don't have almost no other +ways to control this profile it's + + align:start position:0% +ways to control this profile it's + + + align:start position:0% +ways to control this profile it's +material inite absorption so this is the + + align:start position:0% +material inite absorption so this is the + + + align:start position:0% +material inite absorption so this is the +absor + + align:start position:0% +absor + + + align:start position:0% +absor +coefficient and decas the intensity + + align:start position:0% +coefficient and decas the intensity + + + align:start position:0% +coefficient and decas the intensity +decase + + align:start position:0% +decase + + + align:start position:0% +decase +exponentially so now you think about + + align:start position:0% +exponentially so now you think about + + + align:start position:0% +exponentially so now you think about +your most generated electron let's say + + align:start position:0% +your most generated electron let's say + + + align:start position:0% +your most generated electron let's say +this + + align:start position:0% +this + + + align:start position:0% +this +region and you want your space charge in + + align:start position:0% +region and you want your space charge in + + + align:start position:0% +region and you want your space charge in +this reg to overlap it so that you can + + align:start position:0% +this reg to overlap it so that you can + + + align:start position:0% +this reg to overlap it so that you can +separate you can use your field to drive + + align:start position:0% +separate you can use your field to drive + + + align:start position:0% +separate you can use your field to drive +electron to one side hold to the other + + align:start position:0% +electron to one side hold to the other + + + align:start position:0% +electron to one side hold to the other +side right so the dep of this 1 R gives + + align:start position:0% +side right so the dep of this 1 R gives + + + align:start position:0% +side right so the dep of this 1 R gives +you oneus one so that's called + + align:start position:0% +you oneus one so that's called + + + align:start position:0% +you oneus one so that's called +cation so this is where you look at + + align:start position:0% +cation so this is where you look at + + + align:start position:0% +cation so this is where you look at +Material what I should + + align:start position:0% +Material what I should + + + align:start position:0% +Material what I should +choose absorption + + align:start position:0% +choose absorption + + + align:start position:0% +choose absorption +Coe absortion happens above the band Gap + + align:start position:0% +Coe absortion happens above the band Gap + + + align:start position:0% +Coe absortion happens above the band Gap +so band Gap is the first step and then + + align:start position:0% +so band Gap is the first step and then + + + align:start position:0% +so band Gap is the first step and then +you look at Material you say oh silicon + + align:start position:0% +you look at Material you say oh silicon + + + align:start position:0% +you look at Material you say oh silicon +we know so much that's the of cic why + + align:start position:0% +we know so much that's the of cic why + + + align:start position:0% +we know so much that's the of cic why +cicon is a problem because it's really + + align:start position:0% +cicon is a problem because it's really + + + align:start position:0% +cicon is a problem because it's really +just + + align:start position:0% +just + + + align:start position:0% +just +because this + + align:start position:0% +because this + + + align:start position:0% +because this +absortion you see here absorption this + + align:start position:0% +absortion you see here absorption this + + + align:start position:0% +absortion you see here absorption this +is the energy right back is about 1.1 + + align:start position:0% +is the energy right back is about 1.1 + + + align:start position:0% +is the energy right back is about 1.1 +electron + + align:start position:0% +electron + + + align:start position:0% +electron +Vol it's a very slow curve and it's one + + align:start position:0% +Vol it's a very slow curve and it's one + + + align:start position:0% +Vol it's a very slow curve and it's one +over R so this is CM so here is about 10 + + align:start position:0% +over R so this is CM so here is about 10 + + + align:start position:0% +over R so this is CM so here is about 10 +micr so if I use 10 micr so the energy + + align:start position:0% +micr so if I use 10 micr so the energy + + + align:start position:0% +micr so if I use 10 micr so the energy +below + + align:start position:0% +below + + + align:start position:0% +below +1.6 those part of the energy is AB very + + align:start position:0% +1.6 those part of the energy is AB very + + + align:start position:0% +1.6 those part of the energy is AB very +we go through this + + align:start position:0% +we go through this + + + align:start position:0% +we go through this +right it don't + + align:start position:0% +right it don't + + + align:start position:0% +right it don't +get so if it's to this go + + align:start position:0% +get so if it's to this go + + + align:start position:0% +get so if it's to this go +out so that's the the absortion and + + align:start position:0% +out so that's the the absortion and + + + align:start position:0% +out so that's the the absortion and +that's why some say + + align:start position:0% + + + + align:start position:0% + +like6 turn + + align:start position:0% +like6 turn + + + align:start position:0% +like6 turn +right right you have very SP F power so + + align:start position:0% +right right you have very SP F power so + + + align:start position:0% +right right you have very SP F power so +if you have one mic this is the inverse + + align:start position:0% +if you have one mic this is the inverse + + + align:start position:0% +if you have one mic this is the inverse +is One + + align:start position:0% +is One + + + align:start position:0% +is One +mic 10 the + + align:start position:0% +mic 10 the + + + align:start position:0% +mic 10 the +force you m + + align:start position:0% +force you m + + + align:start position:0% +force you m +c okay so with if you want use fil + + align:start position:0% + + + + align:start position:0% + +direct and that's why when people make a + + align:start position:0% +direct and that's why when people make a + + + align:start position:0% +direct and that's why when people make a +cic it's pretty good + + align:start position:0% +cic it's pretty good + + + align:start position:0% +cic it's pretty good +here this is usess + + align:start position:0% +here this is usess + + + align:start position:0% +here this is usess +here right you can generate but you + + align:start position:0% +here right you can generate but you + + + align:start position:0% +here right you can generate but you +don't have much so solar is always first + + align:start position:0% +don't have much so solar is always first + + + align:start position:0% +don't have much so solar is always first +you want to absorb it second you want to + + align:start position:0% +you want to absorb it second you want to + + + align:start position:0% +you want to absorb it second you want to +get the charge to the + + align:start position:0% + + + + align:start position:0% + +elect right so why so different from + + align:start position:0% + + + + align:start position:0% + +the + + align:start position:0% +the + + + align:start position:0% +the +directly right this is what I mentioned + + align:start position:0% +directly right this is what I mentioned + + + align:start position:0% +directly right this is what I mentioned +before whether it's a direct + + align:start position:0% +before whether it's a direct + + + align:start position:0% +before whether it's a direct +semiconductor + + align:start position:0% + + + + align:start position:0% + +Gap like all the others that have sh + + align:start position:0% +Gap like all the others that have sh + + + align:start position:0% +Gap like all the others that have sh +increase direct + + align:start position:0% +increase direct + + + align:start position:0% +increase direct +G so the + + align:start position:0% +G so the + + + align:start position:0% +G so the +full go from here to here leave the + + align:start position:0% +full go from here to here leave the + + + align:start position:0% +full go from here to here leave the +electron to from valus to conduction B + + align:start position:0% +electron to from valus to conduction B + + + align:start position:0% +electron to from valus to conduction B +you need to satisfy satisfy the energy + + align:start position:0% +you need to satisfy satisfy the energy + + + align:start position:0% +you need to satisfy satisfy the energy +conservation so the fullon energy give + + align:start position:0% +conservation so the fullon energy give + + + align:start position:0% +conservation so the fullon energy give +the difference of electron energy so + + align:start position:0% +the difference of electron energy so + + + align:start position:0% +the difference of electron energy so +that's + + align:start position:0% +that's + + + align:start position:0% +that's +energy and second is a + + align:start position:0% +energy and second is a + + + align:start position:0% +energy and second is a +momentum so you have to + + align:start position:0% +momentum so you have to + + + align:start position:0% +momentum so you have to +momentum is H over + + align:start position:0% +momentum is H over + + + align:start position:0% +momentum is H over +Lambda right Lambda of phon is + + align:start position:0% +Lambda right Lambda of phon is + + + align:start position:0% +Lambda right Lambda of phon is +M well Lambda of electron is that + + align:start position:0% +M well Lambda of electron is that + + + align:start position:0% +M well Lambda of electron is that +concept + + align:start position:0% +concept + + + align:start position:0% +concept +Armstrong so the is one over Armstrong + + align:start position:0% +Armstrong so the is one over Armstrong + + + align:start position:0% +Armstrong so the is one over Armstrong +but so one more Lambda is essentially + + align:start position:0% +but so one more Lambda is essentially + + + align:start position:0% +but so one more Lambda is essentially +vertical so the phot don't give you much + + align:start position:0% +vertical so the phot don't give you much + + + align:start position:0% +vertical so the phot don't give you much +momentum that's the problem in indirect + + align:start position:0% +momentum that's the problem in indirect + + + align:start position:0% +momentum that's the problem in indirect +semiconductor right the B Gap is here + + align:start position:0% +semiconductor right the B Gap is here + + + align:start position:0% +semiconductor right the B Gap is here +when you want those + + align:start position:0% +when you want those + + + align:start position:0% +when you want those +the the momentum doesn't match + + align:start position:0% +the the momentum doesn't match + + + align:start position:0% +the the momentum doesn't match +between so if you want to leave this + + align:start position:0% +between so if you want to leave this + + + align:start position:0% +between so if you want to leave this +electron here the photon don't have + + align:start position:0% +electron here the photon don't have + + + align:start position:0% +electron here the photon don't have +enough momentum it has energy doesn't + + align:start position:0% +enough momentum it has energy doesn't + + + align:start position:0% +enough momentum it has energy doesn't +have + + align:start position:0% +have + + + align:start position:0% +have +momentum it has to have like something + + align:start position:0% +momentum it has to have like something + + + align:start position:0% +momentum it has to have like something +else that's Fon can a f or absorb a f + + align:start position:0% +else that's Fon can a f or absorb a f + + + align:start position:0% +else that's Fon can a f or absorb a f +Fon doesn't have much energy but it has + + align:start position:0% +Fon doesn't have much energy but it has + + + align:start position:0% +Fon doesn't have much energy but it has +momentum so this is a why they say so + + align:start position:0% +momentum so this is a why they say so + + + align:start position:0% +momentum so this is a why they say so +you got to have either emission or + + align:start position:0% +you got to have either emission or + + + align:start position:0% +you got to have either emission or +absorption of colon so you have three + + align:start position:0% +absorption of colon so you have three + + + align:start position:0% +absorption of colon so you have three +people now like I said very hard to + + align:start position:0% +people now like I said very hard to + + + align:start position:0% +people now like I said very hard to +schedule three people + + align:start position:0% +schedule three people + + + align:start position:0% +schedule three people +together so the absortion is weaker + + align:start position:0% +together so the absortion is weaker + + + align:start position:0% +together so the absortion is weaker +because when the Fon wants to do it + + align:start position:0% +because when the Fon wants to do it + + + align:start position:0% +because when the Fon wants to do it +there's no + + align:start position:0% + + + + align:start position:0% + +full okay so that's the Dilemma why the + + align:start position:0% +full okay so that's the Dilemma why the + + + align:start position:0% +full okay so that's the Dilemma why the +don't have there and near the back Gap + + align:start position:0% +don't have there and near the back Gap + + + align:start position:0% +don't have there and near the back Gap +and of course once you move to this + + align:start position:0% +and of course once you move to this + + + align:start position:0% +and of course once you move to this +region go up + + align:start position:0% + + + + align:start position:0% + +go okay so that's what I say Soler sale + + align:start position:0% +go okay so that's what I say Soler sale + + + align:start position:0% +go okay so that's what I say Soler sale +essentially you solve one problem make + + align:start position:0% +essentially you solve one problem make + + + align:start position:0% +essentially you solve one problem make +the other problem see or how you can + + align:start position:0% +the other problem see or how you can + + + align:start position:0% +the other problem see or how you can +address those issues that they really + + align:start position:0% +address those issues that they really + + + align:start position:0% +address those issues that they really +electron thing is better you just take + + align:start position:0% +electron thing is better you just take + + + align:start position:0% +electron thing is better you just take +it out before they Rec combine you + + align:start position:0% +it out before they Rec combine you + + + align:start position:0% +it out before they Rec combine you +send four + + align:start position:0% +send four + + + align:start position:0% +send four +times get + + align:start position:0% + + + + align:start position:0% + +okay of course that's related to + + align:start position:0% +okay of course that's related to + + + align:start position:0% +okay of course that's related to +efficiency and the S directly to how + + align:start position:0% +efficiency and the S directly to how + + + align:start position:0% +efficiency and the S directly to how +much material you use that's a cost isue + + align:start position:0% +much material you use that's a cost isue + + + align:start position:0% +much material you use that's a cost isue +also right to have a low cost you need + + align:start position:0% +also right to have a low cost you need + + + align:start position:0% +also right to have a low cost you need +the CER less material always the + + align:start position:0% +the CER less material always the + + + align:start position:0% +the CER less material always the +material cost is + + align:start position:0% +material cost is + + + align:start position:0% +material cost is +better and look at the cost now the + + align:start position:0% +better and look at the cost now the + + + align:start position:0% +better and look at the cost now the +lowest solar cell is from First Solar + + align:start position:0% +lowest solar cell is from First Solar + + + align:start position:0% +lowest solar cell is from First Solar +Bic they have manufacturing cost is + + align:start position:0% +Bic they have manufacturing cost is + + + align:start position:0% +Bic they have manufacturing cost is +about $1 per one + + align:start position:0% + + + + align:start position:0% + +okay and this is where the the back + + align:start position:0% +okay and this is where the the back + + + align:start position:0% +okay and this is where the the back +three assuming certain amount of year + + align:start position:0% +three assuming certain amount of year + + + align:start position:0% +three assuming certain amount of year +you + + align:start position:0% +you + + + align:start position:0% +you +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +use you + + align:start position:0% + + + + align:start position:0% + +have1 it's good it's good good curve + + align:start position:0% +have1 it's good it's good good curve + + + align:start position:0% +have1 it's good it's good good curve +here in terms of the cost but see look + + align:start position:0% +here in terms of the cost but see look + + + align:start position:0% +here in terms of the cost but see look +at + + align:start position:0% + + + + align:start position:0% + +get takes a long time right right now + + align:start position:0% +get takes a long time right right now + + + align:start position:0% +get takes a long time right right now +they work expolation per year about 67 + + align:start position:0% +they work expolation per year about 67 + + + align:start position:0% +they work expolation per year about 67 +Gatt 67 G China put a 100 G Ste every + + align:start position:0% +Gatt 67 G China put a 100 G Ste every + + + align:start position:0% +Gatt 67 G China put a 100 G Ste every +year okay just a BL really just a + + align:start position:0% + + + + align:start position:0% + +BL a + + align:start position:0% + + + + align:start position:0% + +lot okay different type of Sol sales + + align:start position:0% +lot okay different type of Sol sales + + + align:start position:0% +lot okay different type of Sol sales +right + + align:start position:0% +right + + + align:start position:0% +right +and uh city + + align:start position:0% +and uh city + + + align:start position:0% +and uh city +con is the most + + align:start position:0% +con is the most + + + align:start position:0% +con is the most +predominant is cost right single Crystal + + align:start position:0% +predominant is cost right single Crystal + + + align:start position:0% +predominant is cost right single Crystal +mul crystal is + + align:start position:0% +mul crystal is + + + align:start position:0% +mul crystal is +considered GRE almost + + align:start position:0% +considered GRE almost + + + align:start position:0% +considered GRE almost +right and uh what's interesting is all + + align:start position:0% +right and uh what's interesting is all + + + align:start position:0% +right and uh what's interesting is all +the cryst surface has + + align:start position:0% +the cryst surface has + + + align:start position:0% +the cryst surface has +Tex and that's the the light so that + + align:start position:0% +Tex and that's the the light so that + + + align:start position:0% +Tex and that's the the light so that +reduce + + align:start position:0% +reduce + + + align:start position:0% +reduce +reflection reduce reflection not only + + align:start position:0% +reflection reduce reflection not only + + + align:start position:0% +reflection reduce reflection not only +refraction once it get in so the back + + align:start position:0% +refraction once it get in so the back + + + align:start position:0% +refraction once it get in so the back +side is a metal you back you don't want + + align:start position:0% +side is a metal you back you don't want + + + align:start position:0% +side is a metal you back you don't want +to go out some of the pH so the more + + align:start position:0% +to go out some of the pH so the more + + + align:start position:0% +to go out some of the pH so the more +light and the difference between single + + align:start position:0% +light and the difference between single + + + align:start position:0% +light and the difference between single +or mod is SLE you can get a regular + + align:start position:0% + + + + align:start position:0% + +texture manufactur + + align:start position:0% + + + + align:start position:0% + +process and then you got + + align:start position:0% +process and then you got + + + align:start position:0% +process and then you got +say and C here you can see this question + + align:start position:0% +say and C here you can see this question + + + align:start position:0% +say and C here you can see this question +here if you generate here here it has to + + align:start position:0% +here if you generate here here it has to + + + align:start position:0% +here if you generate here here it has to +diffuse you can go both ways right you + + align:start position:0% +diffuse you can go both ways right you + + + align:start position:0% +diffuse you can go both ways right you +don't have a field you have to design so + + align:start position:0% +don't have a field you have to design so + + + align:start position:0% +don't have a field you have to design so +that field can help you go One + + align:start position:0% +that field can help you go One + + + align:start position:0% +that field can help you go One +Direction Why P type is much secret than + + align:start position:0% +Direction Why P type is much secret than + + + align:start position:0% +Direction Why P type is much secret than +the F Tye I don't know it must be + + align:start position:0% +the F Tye I don't know it must be + + + align:start position:0% +the F Tye I don't know it must be +related to the mature par I would + + align:start position:0% +related to the mature par I would + + + align:start position:0% +related to the mature par I would +imagine probably P has combination + + align:start position:0% +imagine probably P has combination + + + align:start position:0% +imagine probably P has combination +together I didn't check + + align:start position:0% +together I didn't check + + + align:start position:0% +together I didn't check +most time people + + align:start position:0% + + + + align:start position:0% + +use + + align:start position:0% + + + + align:start position:0% + +huh I + + align:start position:0% + + + + align:start position:0% + +don't right and you can see here t plus + + align:start position:0% +don't right and you can see here t plus + + + align:start position:0% +don't right and you can see here t plus +trying to make a all + + align:start position:0% +trying to make a all + + + align:start position:0% +trying to make a all +contact right reduce that + + align:start position:0% + + + + align:start position:0% + +sh and uh you have top + + align:start position:0% +sh and uh you have top + + + align:start position:0% +sh and uh you have top +el another + + align:start position:0% +el another + + + align:start position:0% +el another +bre that's a Shel effect met bre they pH + + align:start position:0% +bre that's a Shel effect met bre they pH + + + align:start position:0% +bre that's a Shel effect met bre they pH +on get through that's not good so + + align:start position:0% +on get through that's not good so + + + align:start position:0% +on get through that's not good so +sometimes people even bury the GD down + + align:start position:0% +sometimes people even bury the GD down + + + align:start position:0% +sometimes people even bury the GD down +or make it on the back side through V so + + align:start position:0% +or make it on the back side through V so + + + align:start position:0% +or make it on the back side through V so +there are lot + + align:start position:0% +there are lot + + + align:start position:0% +there are lot +of improvement little bit Improvement + + align:start position:0% +of improvement little bit Improvement + + + align:start position:0% +of improvement little bit Improvement +down over the years + + align:start position:0% + + + + align:start position:0% + +uh and + + align:start position:0% +uh and + + + align:start position:0% +uh and +here say most Early One MA + + align:start position:0% +here say most Early One MA + + + align:start position:0% +here say most Early One MA +silicon MAA silicon we should before is + + align:start position:0% +silicon MAA silicon we should before is + + + align:start position:0% +silicon MAA silicon we should before is +pretty good so you can + + align:start position:0% +pretty good so you can + + + align:start position:0% +pretty good so you can +use but the electron mat electron very + + align:start position:0% +use but the electron mat electron very + + + align:start position:0% +use but the electron mat electron very +hard to move lot of dnic bond + + align:start position:0% +hard to move lot of dnic bond + + + align:start position:0% +hard to move lot of dnic bond +recombination so you got to use really + + align:start position:0% +recombination so you got to use really + + + align:start position:0% +recombination so you got to use really +thin silic about 200 NM + + align:start position:0% +thin silic about 200 NM + + + align:start position:0% +thin silic about 200 NM +and if you can reduce that the UN ther + + align:start position:0% +and if you can reduce that the UN ther + + + align:start position:0% +and if you can reduce that the UN ther +it's probably better two thing your + + align:start position:0% +it's probably better two thing your + + + align:start position:0% +it's probably better two thing your +manufacturing is a problem + + align:start position:0% +manufacturing is a problem + + + align:start position:0% +manufacturing is a problem +P + + align:start position:0% + + + + align:start position:0% + +always but this is actually showing you + + align:start position:0% +always but this is actually showing you + + + align:start position:0% +always but this is actually showing you +just Al Junction I say they if you look + + align:start position:0% +just Al Junction I say they if you look + + + align:start position:0% +just Al Junction I say they if you look +at it this is on steel and top is a + + align:start position:0% +at it this is on steel and top is a + + + align:start position:0% +at it this is on steel and top is a +transparent elect so unlike silicon + + align:start position:0% +transparent elect so unlike silicon + + + align:start position:0% +transparent elect so unlike silicon +silicon you look at the electrode on the + + align:start position:0% +silicon you look at the electrode on the + + + align:start position:0% +silicon you look at the electrode on the +top right it's space across so electron + + align:start position:0% +top right it's space across so electron + + + align:start position:0% +top right it's space across so electron +go here actually diffuse to the + + align:start position:0% +go here actually diffuse to the + + + align:start position:0% +go here actually diffuse to the +elect going to the elect right silicon + + align:start position:0% +elect going to the elect right silicon + + + align:start position:0% +elect going to the elect right silicon +is reason good + + align:start position:0% +is reason good + + + align:start position:0% +is reason good +teration silicon don't work so you got + + align:start position:0% +teration silicon don't work so you got + + + align:start position:0% +teration silicon don't work so you got +have the elect right on top of + + align:start position:0% +have the elect right on top of + + + align:start position:0% +have the elect right on top of +it right so it's transparent + + align:start position:0% + + + + align:start position:0% + +conduction and uh this is the + + align:start position:0% +conduction and uh this is the + + + align:start position:0% +conduction and uh this is the +right the active + + align:start position:0% +right the active + + + align:start position:0% +right the active +reg 6 + + align:start position:0% + + + + align:start position:0% + +mic and this is six + + align:start position:0% + + + + align:start position:0% + +SP it's a between reculation and + + align:start position:0% +SP it's a between reculation and + + + align:start position:0% +SP it's a between reculation and +absorption to increase absortion using S + + align:start position:0% +absorption to increase absortion using S + + + align:start position:0% +absorption to increase absortion using S +it's always better if you can the better + + align:start position:0% +it's always better if you can the better + + + align:start position:0% +it's always better if you can the better +if you can use the S the first step you + + align:start position:0% +if you can use the S the first step you + + + align:start position:0% +if you can use the S the first step you +can prop light we're doing some + + align:start position:0% +can prop light we're doing some + + + align:start position:0% +can prop light we're doing some +research capitalize + + align:start position:0% +research capitalize + + + align:start position:0% +research capitalize +those + + align:start position:0% + + + + align:start position:0% + +us + + align:start position:0% +us + + + align:start position:0% +us +what + + align:start position:0% +what + + + align:start position:0% +what +uh here is + + align:start position:0% +uh here is + + + align:start position:0% +uh here is +about I'm not sure whether that's + + align:start position:0% +about I'm not sure whether that's + + + align:start position:0% +about I'm not sure whether that's +best just just copy from find to + + align:start position:0% + + + + align:start position:0% + +show people are doing transparent + + align:start position:0% +show people are doing transparent + + + align:start position:0% +show people are doing transparent +conductor also trying to improve the + + align:start position:0% +conductor also trying to improve the + + + align:start position:0% +conductor also trying to improve the +conductivity basically you want a very + + align:start position:0% +conductivity basically you want a very + + + align:start position:0% +conductivity basically you want a very +highly conduct it so if you highly + + align:start position:0% +highly conduct it so if you highly + + + align:start position:0% +highly conduct it so if you highly +conducted the CER is better because the + + align:start position:0% +conducted the CER is better because the + + + align:start position:0% +conducted the CER is better because the +free electron in this material + + align:start position:0% +free electron in this material + + + align:start position:0% +free electron in this material +also which generally you don't want + + align:start position:0% + + + + align:start position:0% + +that right + + align:start position:0% +that right + + + align:start position:0% +that right +ideally if you you reduce cost by your + + align:start position:0% +ideally if you you reduce cost by your + + + align:start position:0% +ideally if you you reduce cost by your +situation the problem of thiser is that + + align:start position:0% +situation the problem of thiser is that + + + align:start position:0% +situation the problem of thiser is that +it's even worse than M of + + align:start position:0% +it's even worse than M of + + + align:start position:0% +it's even worse than M of +cicon right you generate a immediate Rec + + align:start position:0% +cicon right you generate a immediate Rec + + + align:start position:0% +cicon right you generate a immediate Rec +combine the combination is very fast in + + align:start position:0% +combine the combination is very fast in + + + align:start position:0% +combine the combination is very fast in +fact when first gener they bond it + + align:start position:0% +fact when first gener they bond it + + + align:start position:0% +fact when first gener they bond it +together they not even separate electon + + align:start position:0% +together they not even separate electon + + + align:start position:0% +together they not even separate electon +or hold this B state is called Aon so + + align:start position:0% +or hold this B state is called Aon so + + + align:start position:0% +or hold this B state is called Aon so +MIT has a Aon Center Center M we have I + + align:start position:0% +MIT has a Aon Center Center M we have I + + + align:start position:0% +MIT has a Aon Center Center M we have I +have saying a solar thermal Center + + align:start position:0% +have saying a solar thermal Center + + + align:start position:0% +have saying a solar thermal Center +ACC there is the whole issue to find how + + align:start position:0% +ACC there is the whole issue to find how + + + align:start position:0% +ACC there is the whole issue to find how +I can separate this + + align:start position:0% +I can separate this + + + align:start position:0% +I can separate this +X and make electron go one way and the + + align:start position:0% +X and make electron go one way and the + + + align:start position:0% +X and make electron go one way and the +hole go the + + align:start position:0% + + + + align:start position:0% + +other right so in that case you look at + + align:start position:0% +other right so in that case you look at + + + align:start position:0% +other right so in that case you look at +this really thin uh 220 + + align:start position:0% +this really thin uh 220 + + + align:start position:0% +this really thin uh 220 +NM try to + + align:start position:0% +NM try to + + + align:start position:0% +NM try to +separate but that's still difficult so + + align:start position:0% +separate but that's still difficult so + + + align:start position:0% +separate but that's still difficult so +people now doing the soal bul junction + + align:start position:0% +people now doing the soal bul junction + + + align:start position:0% +people now doing the soal bul junction +sales so put the two type of molecule + + align:start position:0% +sales so put the two type of molecule + + + align:start position:0% +sales so put the two type of molecule +one conduct electron one conduct so + + align:start position:0% +one conduct electron one conduct so + + + align:start position:0% +one conduct electron one conduct so +locally you gener electron righta you + + align:start position:0% +locally you gener electron righta you + + + align:start position:0% +locally you gener electron righta you +want to IM separate the go one + + align:start position:0% + + + + align:start position:0% + +one gra cell right so this is not a + + align:start position:0% +one gra cell right so this is not a + + + align:start position:0% +one gra cell right so this is not a +solid cell it's act a liquid + + align:start position:0% +solid cell it's act a liquid + + + align:start position:0% +solid cell it's act a liquid +C and uh what it has is tianium dioxide + + align:start position:0% +C and uh what it has is tianium dioxide + + + align:start position:0% +C and uh what it has is tianium dioxide +n + + align:start position:0% + + + + align:start position:0% + +okay dioxide has B three electron Vols + + align:start position:0% +okay dioxide has B three electron Vols + + + align:start position:0% +okay dioxide has B three electron Vols +to L not much more + + align:start position:0% +to L not much more + + + align:start position:0% +to L not much more +full + + align:start position:0% +full + + + align:start position:0% +full +right and so + + align:start position:0% +right and so + + + align:start position:0% +right and so +what does you put a d on top of + + align:start position:0% +what does you put a d on top of + + + align:start position:0% +what does you put a d on top of +that and this D is called photosynth so + + align:start position:0% +that and this D is called photosynth so + + + align:start position:0% +that and this D is called photosynth so +this is where + + align:start position:0% + + + + align:start position:0% + +phot and photons + + align:start position:0% +phot and photons + + + align:start position:0% +phot and photons +absorb time + + align:start position:0% + + + + align:start position:0% + +more gener + + align:start position:0% +more gener + + + align:start position:0% +more gener +electron + + align:start position:0% +electron + + + align:start position:0% +electron +ex before they dissociate they are and + + align:start position:0% +ex before they dissociate they are and + + + align:start position:0% +ex before they dissociate they are and +you one thing + + align:start position:0% +you one thing + + + align:start position:0% +you one thing +dissociate separate into electron hole + + align:start position:0% +dissociate separate into electron hole + + + align:start position:0% +dissociate separate into electron hole +and electron go into + + align:start position:0% +and electron go into + + + align:start position:0% +and electron go into +nle so the nle diffuse now there's no + + align:start position:0% +nle so the nle diffuse now there's no + + + align:start position:0% +nle so the nle diffuse now there's no +field really diffusion + + align:start position:0% +field really diffusion + + + align:start position:0% +field really diffusion +process okay so see the WR out so that's + + align:start position:0% +process okay so see the WR out so that's + + + align:start position:0% +process okay so see the WR out so that's +why people try to do n wires so that + + align:start position:0% +why people try to do n wires so that + + + align:start position:0% +why people try to do n wires so that +give a better pass to electr rather than + + align:start position:0% +give a better pass to electr rather than + + + align:start position:0% +give a better pass to electr rather than +n but the problem is when you put n wire + + align:start position:0% +n but the problem is when you put n wire + + + align:start position:0% +n but the problem is when you put n wire +your surface area for abortion also + + align:start position:0% +your surface area for abortion also + + + align:start position:0% +your surface area for abortion also +change right here you can have this area + + align:start position:0% +change right here you can have this area + + + align:start position:0% +change right here you can have this area +surface area + + align:start position:0% +surface area + + + align:start position:0% +surface area +one your your your not aware is only + + align:start position:0% +one your your your not aware is only + + + align:start position:0% +one your your your not aware is only +this + + align:start position:0% +this + + + align:start position:0% +this +surface right vertical so the surface + + align:start position:0% +surface right vertical so the surface + + + align:start position:0% +surface right vertical so the surface +area of absortion + + align:start position:0% +area of absortion + + + align:start position:0% +area of absortion +so has Advantage is just almost like 3D + + align:start position:0% +so has Advantage is just almost like 3D + + + align:start position:0% +so has Advantage is just almost like 3D +W around the + + align:start position:0% +W around the + + + align:start position:0% +W around the +more there + + align:start position:0% + + + + align:start position:0% + +always and + + align:start position:0% +always and + + + align:start position:0% +always and +the ho go to the + + align:start position:0% +the ho go to the + + + align:start position:0% +the ho go to the +liquid and this is a chemical reaction + + align:start position:0% +liquid and this is a chemical reaction + + + align:start position:0% +liquid and this is a chemical reaction +noise not just a whole diffus theid + + align:start position:0% +noise not just a whole diffus theid + + + align:start position:0% +noise not just a whole diffus theid +there no + + align:start position:0% +there no + + + align:start position:0% +there no +can so so the ho + + align:start position:0% +can so so the ho + + + align:start position:0% +can so so the ho +oxidize the Moes in the case very often + + align:start position:0% +oxidize the Moes in the case very often + + + align:start position:0% +oxidize the Moes in the case very often +the + + align:start position:0% +the + + + align:start position:0% +the +iodine + + align:start position:0% +iodine + + + align:start position:0% +iodine +iodine say iodine 3 + + align:start position:0% +iodine say iodine 3 + + + align:start position:0% +iodine say iodine 3 +and this charged molecule diffus to + + align:start position:0% +and this charged molecule diffus to + + + align:start position:0% +and this charged molecule diffus to +the again + + align:start position:0% +the again + + + align:start position:0% +the again +diffus so electron diffuse to one elect + + align:start position:0% +diffus so electron diffuse to one elect + + + align:start position:0% +diffus so electron diffuse to one elect +whole diffuse to the other elect where + + align:start position:0% +whole diffuse to the other elect where + + + align:start position:0% +whole diffuse to the other elect where +they reduce and they reduce the diffuse + + align:start position:0% +they reduce and they reduce the diffuse + + + align:start position:0% +they reduce and they reduce the diffuse +back sounds like a very cool process + + align:start position:0% +back sounds like a very cool process + + + align:start position:0% +back sounds like a very cool process +right the idea is again this you can + + align:start position:0% +right the idea is again this you can + + + align:start position:0% +right the idea is again this you can +pound see was pretty good getting that + + align:start position:0% +pound see was pretty good getting that + + + align:start position:0% +pound see was pretty good getting that + + align:start position:0% + + + align:start position:0% +of + + align:start position:0% +of + + + align:start position:0% +of +this and see the so this + + align:start position:0% +this and see the so this + + + align:start position:0% +this and see the so this +is a flat + + align:start position:0% + + + + align:start position:0% + +surface so that's pretty much what I + + align:start position:0% +surface so that's pretty much what I + + + align:start position:0% +surface so that's pretty much what I +want to say and on time and this is the + + align:start position:0% +want to say and on time and this is the + + + align:start position:0% +want to say and on time and this is the +sort of + + align:start position:0% +sort of + + + align:start position:0% +sort of +dream okay the dream in the sense here's + + align:start position:0% +dream okay the dream in the sense here's + + + align:start position:0% +dream okay the dream in the sense here's +the cost here is efficiency you want the + + align:start position:0% +the cost here is efficiency you want the + + + align:start position:0% +the cost here is efficiency you want the +low cost high efficiency right + + align:start position:0% +low cost high efficiency right + + + align:start position:0% +low cost high efficiency right +silicon in the first generation called + + align:start position:0% +silicon in the first generation called + + + align:start position:0% +silicon in the first generation called +gen + + align:start position:0% +gen + + + align:start position:0% +gen +one fil is here lower efficiency but + + align:start position:0% +one fil is here lower efficiency but + + + align:start position:0% +one fil is here lower efficiency but +lower cost and in fact they make a good + + align:start position:0% +lower cost and in fact they make a good + + + align:start position:0% +lower cost and in fact they make a good +business at least + + align:start position:0% +business at least + + + align:start position:0% +business at least +first + + align:start position:0% +first + + + align:start position:0% +first +B and people go to + + align:start position:0% +B and people go to + + + align:start position:0% +B and people go to +G no winner in gen 3 okay this is where + + align:start position:0% +G no winner in gen 3 okay this is where + + + align:start position:0% +G no winner in gen 3 okay this is where +you guys could be win + + align:start position:0% + + + + align:start position:0% + +okay I think that's it \ No newline at end of file diff --git a/jcvxkX2V-SM.txt b/jcvxkX2V-SM.txt new file mode 100644 index 0000000000000000000000000000000000000000..0c226d97fcb9143dafe45fc7965e1c51b7ba39a3 --- /dev/null +++ b/jcvxkX2V-SM.txt @@ -0,0 +1,787 @@ +align:start position:0% + +so we saw in the previous video that the + + align:start position:0% +so we saw in the previous video that the + + + align:start position:0% +so we saw in the previous video that the +house prices were distributed over the + + align:start position:0% +house prices were distributed over the + + + align:start position:0% +house prices were distributed over the +area in an interesting way it's + + align:start position:0% +area in an interesting way it's + + + align:start position:0% +area in an interesting way it's +certainly not a kind of linear way and + + align:start position:0% +certainly not a kind of linear way and + + + align:start position:0% +certainly not a kind of linear way and +we wouldn't in searly expect linear + + align:start position:0% +we wouldn't in searly expect linear + + + align:start position:0% +we wouldn't in searly expect linear +regression to do very well at predicting + + align:start position:0% +regression to do very well at predicting + + + align:start position:0% +regression to do very well at predicting +house price just given latitude and + + align:start position:0% +house price just given latitude and + + + align:start position:0% +house price just given latitude and +longitude we can kind of develop that + + align:start position:0% +longitude we can kind of develop that + + + align:start position:0% +longitude we can kind of develop that +intuition more by plotting the + + align:start position:0% +intuition more by plotting the + + + align:start position:0% +intuition more by plotting the +relationship between latitude and house + + align:start position:0% +relationship between latitude and house + + + align:start position:0% +relationship between latitude and house +prices which doesn't look very linear or + + align:start position:0% +prices which doesn't look very linear or + + + align:start position:0% +prices which doesn't look very linear or +the longitude and the house prices which + + align:start position:0% +the longitude and the house prices which + + + align:start position:0% +the longitude and the house prices which +also looks pretty non non linear so + + align:start position:0% +also looks pretty non non linear so + + + align:start position:0% +also looks pretty non non linear so +we'll fit we'll try fitting a linear + + align:start position:0% +we'll fit we'll try fitting a linear + + + align:start position:0% +we'll fit we'll try fitting a linear +regression anyway so let's call it lat + + align:start position:0% +regression anyway so let's call it lat + + + align:start position:0% +regression anyway so let's call it lat +lon LM and we'll use the Eliam command + + align:start position:0% +lon LM and we'll use the Eliam command + + + align:start position:0% +lon LM and we'll use the Eliam command +the linear model to predict house prices + + align:start position:0% +the linear model to predict house prices + + + align:start position:0% +the linear model to predict house prices +based on latitude and longitude using + + align:start position:0% +based on latitude and longitude using + + + align:start position:0% +based on latitude and longitude using +the Boston data set and if we take a + + align:start position:0% +the Boston data set and if we take a + + + align:start position:0% +the Boston data set and if we take a +look at our linear regression we see the + + align:start position:0% +look at our linear regression we see the + + + align:start position:0% +look at our linear regression we see the +a squared is around 0.1 which is not + + align:start position:0% +a squared is around 0.1 which is not + + + align:start position:0% +a squared is around 0.1 which is not +great the latitude is not significant + + align:start position:0% +great the latitude is not significant + + + align:start position:0% +great the latitude is not significant +which means the north-south differences + + align:start position:0% +which means the north-south differences + + + align:start position:0% +which means the north-south differences +and going to be really used at all + + align:start position:0% +and going to be really used at all + + + align:start position:0% +and going to be really used at all +longitude is significant and it's + + align:start position:0% +longitude is significant and it's + + + align:start position:0% +longitude is significant and it's +negative which we can interpret as as we + + align:start position:0% +negative which we can interpret as as we + + + align:start position:0% +negative which we can interpret as as we +go towards the ocean as we go towards + + align:start position:0% +go towards the ocean as we go towards + + + align:start position:0% +go towards the ocean as we go towards +the East house prices decrease linearly + + align:start position:0% +the East house prices decrease linearly + + + align:start position:0% +the East house prices decrease linearly +so this all seems kind of unlikely but + + align:start position:0% +so this all seems kind of unlikely but + + + align:start position:0% +so this all seems kind of unlikely but +let's work with it so let's see how this + + align:start position:0% +let's work with it so let's see how this + + + align:start position:0% +let's work with it so let's see how this +linear regression model looks on a plot + + align:start position:0% +linear regression model looks on a plot + + + align:start position:0% +linear regression model looks on a plot +so let's plot the since the strikes + + align:start position:0% +so let's plot the since the strikes + + + align:start position:0% +so let's plot the since the strikes +again okay now Brenda before we had from + + align:start position:0% +again okay now Brenda before we had from + + + align:start position:0% +again okay now Brenda before we had from +the previous video we plotted the above + + align:start position:0% +the previous video we plotted the above + + + align:start position:0% +the previous video we plotted the above +median house prices so we're gonna do + + align:start position:0% +median house prices so we're gonna do + + + align:start position:0% +median house prices so we're gonna do +that one more time + + align:start position:0% +that one more time + + + align:start position:0% +that one more time +the meeting was twenty one point two + + align:start position:0% + + + + align:start position:0% + +we had the color was red and we used + + align:start position:0% +we had the color was red and we used + + + align:start position:0% +we had the color was red and we used +solid dots ha whoops see you wrote it + + align:start position:0% +solid dots ha whoops see you wrote it + + + align:start position:0% +solid dots ha whoops see you wrote it +down I use the plot command instead of + + align:start position:0% +down I use the plot command instead of + + + align:start position:0% +down I use the plot command instead of +the points command and it plotted just + + align:start position:0% +the points command and it plotted just + + + align:start position:0% +the points command and it plotted just +some new points I meant to do + + align:start position:0% +some new points I meant to do + + + align:start position:0% +some new points I meant to do +plot the original points and use the + + align:start position:0% +plot the original points and use the + + + align:start position:0% +plot the original points and use the +points command to plot it on top of the + + align:start position:0% +points command to plot it on top of the + + + align:start position:0% +points command to plot it on top of the +existing plot okay so that's more like + + align:start position:0% +existing plot okay so that's more like + + + align:start position:0% +existing plot okay so that's more like +it + + align:start position:0% +it + + + align:start position:0% +it +so now we have the median values we have + + align:start position:0% +so now we have the median values we have + + + align:start position:0% +so now we have the median values we have +the above median value census tracks so + + align:start position:0% +the above median value census tracks so + + + align:start position:0% +the above median value census tracks so +okay we want to see now the question + + align:start position:0% +okay we want to see now the question + + + align:start position:0% +okay we want to see now the question +we're going to ask and then plot is what + + align:start position:0% +we're going to ask and then plot is what + + + align:start position:0% +we're going to ask and then plot is what +does the linear regression model think + + align:start position:0% +does the linear regression model think + + + align:start position:0% +does the linear regression model think +is above median so we could just do this + + align:start position:0% +is above median so we could just do this + + + align:start position:0% +is above median so we could just do this +pretty easily + + align:start position:0% +pretty easily + + + align:start position:0% +pretty easily +we have lat lon LM has a field fitted + + align:start position:0% +we have lat lon LM has a field fitted + + + align:start position:0% +we have lat lon LM has a field fitted +values and this is what the linear + + align:start position:0% +values and this is what the linear + + + align:start position:0% +values and this is what the linear +regression model predicts for each of a + + align:start position:0% +regression model predicts for each of a + + + align:start position:0% +regression model predicts for each of a +506 census tracts so we'll plot these on + + align:start position:0% +506 census tracts so we'll plot these on + + + align:start position:0% +506 census tracts so we'll plot these on +top Boston lon + + align:start position:0% +top Boston lon + + + align:start position:0% +top Boston lon +take all the census tracts such that the + + align:start position:0% +take all the census tracts such that the + + + align:start position:0% +take all the census tracts such that the +lat/long alliums + + align:start position:0% +lat/long alliums + + + align:start position:0% +lat/long alliums +fitted values are above the median take + + align:start position:0% +fitted values are above the median take + + + align:start position:0% +fitted values are above the median take +the ladder shoes to + + align:start position:0% + + + + align:start position:0% + +and I'm gonna make them blue but let's + + align:start position:0% +and I'm gonna make them blue but let's + + + align:start position:0% +and I'm gonna make them blue but let's +pause for a moment and think if we use + + align:start position:0% +pause for a moment and think if we use + + + align:start position:0% +pause for a moment and think if we use +the dots again we'll cover up the red + + align:start position:0% +the dots again we'll cover up the red + + + align:start position:0% +the dots again we'll cover up the red +dots and cover up some of the black dots + + align:start position:0% +dots and cover up some of the black dots + + + align:start position:0% +dots and cover up some of the black dots +what we won't be able to see is where + + align:start position:0% +what we won't be able to see is where + + + align:start position:0% +what we won't be able to see is where +the red dots and the blue dots match up + + align:start position:0% +the red dots and the blue dots match up + + + align:start position:0% +the red dots and the blue dots match up +you know we're interesting seeing how + + align:start position:0% +you know we're interesting seeing how + + + align:start position:0% +you know we're interesting seeing how +the linear regression matches up with + + align:start position:0% +the linear regression matches up with + + + align:start position:0% +the linear regression matches up with +the truth so it'd be ideal if we could + + align:start position:0% +the truth so it'd be ideal if we could + + + align:start position:0% +the truth so it'd be ideal if we could +plot the linear regression blue dots on + + align:start position:0% +plot the linear regression blue dots on + + + align:start position:0% +plot the linear regression blue dots on +top of the red dots in some way that we + + align:start position:0% +top of the red dots in some way that we + + + align:start position:0% +top of the red dots in some way that we +can still see the red does it turns out + + align:start position:0% +can still see the red does it turns out + + + align:start position:0% +can still see the red does it turns out +that you can actually pass in characters + + align:start position:0% +that you can actually pass in characters + + + align:start position:0% +that you can actually pass in characters +to this PCH option so since we're + + align:start position:0% +to this PCH option so since we're + + + align:start position:0% +to this PCH option so since we're +talking about money + + align:start position:0% +talking about money + + + align:start position:0% +talking about money +let's plot dollar signs instead of + + align:start position:0% +let's plot dollar signs instead of + + + align:start position:0% +let's plot dollar signs instead of +points and there you have it so the + + align:start position:0% +points and there you have it so the + + + align:start position:0% +points and there you have it so the +linear regression model has plotted a + + align:start position:0% +linear regression model has plotted a + + + align:start position:0% +linear regression model has plotted a +dollar sign for every time that things + + align:start position:0% +dollar sign for every time that things + + + align:start position:0% +dollar sign for every time that things +are census tract as above median value + + align:start position:0% +are census tract as above median value + + + align:start position:0% +are census tract as above median value +and you can see that indeed there's + + align:start position:0% +and you can see that indeed there's + + + align:start position:0% +and you can see that indeed there's +almost you can see the sharp line that + + align:start position:0% +almost you can see the sharp line that + + + align:start position:0% +almost you can see the sharp line that +the linear regression defines and how + + align:start position:0% +the linear regression defines and how + + + align:start position:0% +the linear regression defines and how +it's pretty much vertical because + + align:start position:0% +it's pretty much vertical because + + + align:start position:0% +it's pretty much vertical because +remember before the latitude variable + + align:start position:0% +remember before the latitude variable + + + align:start position:0% +remember before the latitude variable +was not very significant in the + + align:start position:0% +was not very significant in the + + + align:start position:0% +was not very significant in the +regression so that's interesting and + + align:start position:0% +regression so that's interesting and + + + align:start position:0% +regression so that's interesting and +pretty wrong one thing that really + + align:start position:0% +pretty wrong one thing that really + + + align:start position:0% +pretty wrong one thing that really +stands out is how it says Boston is + + align:start position:0% +stands out is how it says Boston is + + + align:start position:0% +stands out is how it says Boston is +mostly above median even though we we + + align:start position:0% +mostly above median even though we we + + + align:start position:0% +mostly above median even though we we +saw a right from the step is a big non + + align:start position:0% +saw a right from the step is a big non + + + align:start position:0% +saw a right from the step is a big non +red spot right in the middle of Boston + + align:start position:0% +red spot right in the middle of Boston + + + align:start position:0% +red spot right in the middle of Boston +where the the house prices were below + + align:start position:0% +where the the house prices were below + + + align:start position:0% +where the the house prices were below +the median so the linear regression + + align:start position:0% +the median so the linear regression + + + align:start position:0% +the median so the linear regression +model isn't really doing a good job and + + align:start position:0% +model isn't really doing a good job and + + + align:start position:0% +model isn't really doing a good job and +it's completely ignored everything to + + align:start position:0% +it's completely ignored everything to + + + align:start position:0% +it's completely ignored everything to +the right side of a picture \ No newline at end of file diff --git a/kphOAvHVy0E.txt b/kphOAvHVy0E.txt new file mode 100644 index 0000000000000000000000000000000000000000..b31640cbc0de638e9862a17a2f0362b6689755bf --- /dev/null +++ b/kphOAvHVy0E.txt @@ -0,0 +1,595 @@ +align:start position:0% + +currents induced in a conducting shell + + align:start position:0% +currents induced in a conducting shell + + + align:start position:0% +currents induced in a conducting shell +oppose the penetration of a suddenly + + align:start position:0% +oppose the penetration of a suddenly + + + align:start position:0% +oppose the penetration of a suddenly +applied magnetic field + + align:start position:0% +applied magnetic field + + + align:start position:0% +applied magnetic field +and cause a force that tends to crush + + align:start position:0% +and cause a force that tends to crush + + + align:start position:0% +and cause a force that tends to crush +the shell + + align:start position:0% + + + + align:start position:0% + +here again is edgerton's boomer + + align:start position:0% +here again is edgerton's boomer + + + align:start position:0% +here again is edgerton's boomer +apparatus composed of the driver coil + + align:start position:0% + + + + align:start position:0% + +and large capacitor bank with total + + align:start position:0% +and large capacitor bank with total + + + align:start position:0% +and large capacitor bank with total +capacitance of 48 microfarads + + align:start position:0% +capacitance of 48 microfarads + + + align:start position:0% +capacitance of 48 microfarads +the capacitor bank is charged to 4 + + align:start position:0% +the capacitor bank is charged to 4 + + + align:start position:0% +the capacitor bank is charged to 4 +kilovolts + + align:start position:0% + + + + align:start position:0% + +discharging the capacitor into the coil + + align:start position:0% +discharging the capacitor into the coil + + + align:start position:0% +discharging the capacitor into the coil +with this trigger + + align:start position:0% +with this trigger + + + align:start position:0% +with this trigger +generates a large transient current in + + align:start position:0% +generates a large transient current in + + + align:start position:0% +generates a large transient current in +the coil which in turn generates a large + + align:start position:0% +the coil which in turn generates a large + + + align:start position:0% +the coil which in turn generates a large +magnetic field + + align:start position:0% + + + + align:start position:0% + +currents induced in the thin foil + + align:start position:0% +currents induced in the thin foil + + + align:start position:0% +currents induced in the thin foil +cylinder to oppose the penetration of + + align:start position:0% +cylinder to oppose the penetration of + + + align:start position:0% +cylinder to oppose the penetration of +magnetic field + + align:start position:0% + + + + align:start position:0% + +cause a radial inwards force on the + + align:start position:0% +cause a radial inwards force on the + + + align:start position:0% +cause a radial inwards force on the +cylinder but tends to crush it + + align:start position:0% + + + + align:start position:0% + +let's see that again + + align:start position:0% + + + + align:start position:0% + +with this time constant in mind let's + + align:start position:0% +with this time constant in mind let's + + + align:start position:0% +with this time constant in mind let's +see what the actual fields are + + align:start position:0% +see what the actual fields are + + + align:start position:0% +see what the actual fields are +because this is a single shot experiment + + align:start position:0% +because this is a single shot experiment + + + align:start position:0% +because this is a single shot experiment +we use the storage oscilloscope to + + align:start position:0% +we use the storage oscilloscope to + + + align:start position:0% +we use the storage oscilloscope to +record and store measured waveforms + + align:start position:0% +record and store measured waveforms + + + align:start position:0% +record and store measured waveforms +we use this current probe to record the + + align:start position:0% +we use this current probe to record the + + + align:start position:0% +we use this current probe to record the +current in the coil + + align:start position:0% +current in the coil + + + align:start position:0% +current in the coil +in the upper oscilloscope trace its gain + + align:start position:0% +in the upper oscilloscope trace its gain + + + align:start position:0% +in the upper oscilloscope trace its gain +has been adjusted to 500 amps per + + align:start position:0% +has been adjusted to 500 amps per + + + align:start position:0% +has been adjusted to 500 amps per +centimeter + + align:start position:0% +centimeter + + + align:start position:0% +centimeter +this small 200 turn coil is placed just + + align:start position:0% +this small 200 turn coil is placed just + + + align:start position:0% +this small 200 turn coil is placed just +above the driver coil to record the time + + align:start position:0% +above the driver coil to record the time + + + align:start position:0% +above the driver coil to record the time +derivative of magnetic flux on the lower + + align:start position:0% +derivative of magnetic flux on the lower + + + align:start position:0% +derivative of magnetic flux on the lower +oscilloscope trace + + align:start position:0% +oscilloscope trace + + + align:start position:0% +oscilloscope trace +we charge the capacitor to four + + align:start position:0% +we charge the capacitor to four + + + align:start position:0% +we charge the capacitor to four +kilovolts + + align:start position:0% + + + + align:start position:0% + +as we discharge the capacitor bank we + + align:start position:0% +as we discharge the capacitor bank we + + + align:start position:0% +as we discharge the capacitor bank we +record the current oscillations in the + + align:start position:0% +record the current oscillations in the + + + align:start position:0% +record the current oscillations in the +driver coil on the upper scope trace + + align:start position:0% +driver coil on the upper scope trace + + + align:start position:0% +driver coil on the upper scope trace +and the time derivative of the magnetic + + align:start position:0% +and the time derivative of the magnetic + + + align:start position:0% +and the time derivative of the magnetic +flux on the lower scope trace + + align:start position:0% +flux on the lower scope trace + + + align:start position:0% +flux on the lower scope trace +we see decaying oscillations + + align:start position:0% +we see decaying oscillations + + + align:start position:0% +we see decaying oscillations +characteristic of the rlc circuit + + align:start position:0% +characteristic of the rlc circuit + + + align:start position:0% +characteristic of the rlc circuit +for our circuit parameters the frequency + + align:start position:0% +for our circuit parameters the frequency + + + align:start position:0% +for our circuit parameters the frequency +of oscillation is about four kilohertz + + align:start position:0% +of oscillation is about four kilohertz + + + align:start position:0% +of oscillation is about four kilohertz +we store these waveforms and reset the + + align:start position:0% +we store these waveforms and reset the + + + align:start position:0% +we store these waveforms and reset the +scope trigger + + align:start position:0% +scope trigger + + + align:start position:0% +scope trigger +we now place the foil cylinder around + + align:start position:0% +we now place the foil cylinder around + + + align:start position:0% +we now place the foil cylinder around +the magnetic flux sensing coil + + align:start position:0% + + + + align:start position:0% + +remember the upper trace records the + + align:start position:0% +remember the upper trace records the + + + align:start position:0% +remember the upper trace records the +driver coil current + + align:start position:0% +driver coil current + + + align:start position:0% +driver coil current +which imposes the magnetic field while + + align:start position:0% +which imposes the magnetic field while + + + align:start position:0% +which imposes the magnetic field while +the lower trace records the sensing coil + + align:start position:0% +the lower trace records the sensing coil + + + align:start position:0% +the lower trace records the sensing coil +signal + + align:start position:0% +signal + + + align:start position:0% +signal +now inside the cylinder + + align:start position:0% +now inside the cylinder + + + align:start position:0% +now inside the cylinder +we see that the driver coil current + + align:start position:0% +we see that the driver coil current + + + align:start position:0% +we see that the driver coil current +waveform has diminished somewhat + + align:start position:0% +waveform has diminished somewhat + + + align:start position:0% +waveform has diminished somewhat +but that the sensing coil waveform + + align:start position:0% +but that the sensing coil waveform + + + align:start position:0% +but that the sensing coil waveform +within the foil cylinder has decreased + + align:start position:0% +within the foil cylinder has decreased + + + align:start position:0% +within the foil cylinder has decreased +even more + + align:start position:0% +even more + + + align:start position:0% +even more +the magnetic field has been shielded out + + align:start position:0% +the magnetic field has been shielded out + + + align:start position:0% +the magnetic field has been shielded out +of the cylinder + + align:start position:0% + + + + align:start position:0% + +let's measure the field inside another + + align:start position:0% +let's measure the field inside another + + + align:start position:0% +let's measure the field inside another +aluminum cylinder that is about a + + align:start position:0% +aluminum cylinder that is about a + + + align:start position:0% +aluminum cylinder that is about a +hundred times thicker + + align:start position:0% +hundred times thicker + + + align:start position:0% +hundred times thicker +the bottom scope trace shows the field + + align:start position:0% +the bottom scope trace shows the field + + + align:start position:0% +the bottom scope trace shows the field +without the cylinder + + align:start position:0% +without the cylinder + + + align:start position:0% +without the cylinder +let's reset the scope and put the thick + + align:start position:0% +let's reset the scope and put the thick + + + align:start position:0% +let's reset the scope and put the thick +cylinder around the sensing coil + + align:start position:0% + + + + align:start position:0% + +the new lower trace is essentially zero + + align:start position:0% +the new lower trace is essentially zero + + + align:start position:0% +the new lower trace is essentially zero +for a mega tau + + align:start position:0% +for a mega tau + + + align:start position:0% +for a mega tau +m of order a hundred the magnetic field + + align:start position:0% +m of order a hundred the magnetic field + + + align:start position:0% +m of order a hundred the magnetic field +inside the cylinder is greatly reduced \ No newline at end of file diff --git a/lbtrbE_kK_Q.txt b/lbtrbE_kK_Q.txt new file mode 100644 index 0000000000000000000000000000000000000000..cf17b2cb4d54fd5231f026d9f8bcb7c81a9094d7 --- /dev/null +++ b/lbtrbE_kK_Q.txt @@ -0,0 +1,7715 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT OpenCourseWare continue to + + align:start position:0% +will help MIT OpenCourseWare continue to + + + align:start position:0% +will help MIT OpenCourseWare continue to +offer high quality educational resources + + align:start position:0% +offer high quality educational resources + + + align:start position:0% +offer high quality educational resources +for free + + align:start position:0% +for free + + + align:start position:0% +for free +to make a donation or view additional + + align:start position:0% +to make a donation or view additional + + + align:start position:0% +to make a donation or view additional +materials from hundreds of MIT courses + + align:start position:0% +materials from hundreds of MIT courses + + + align:start position:0% +materials from hundreds of MIT courses +visit MIT opencourseware at ocw.mit.edu + + align:start position:0% + + + + align:start position:0% + +I wanted to use this final time our we + + align:start position:0% +I wanted to use this final time our we + + + align:start position:0% +I wanted to use this final time our we +have together to summarize a few of this + + align:start position:0% +have together to summarize a few of this + + + align:start position:0% +have together to summarize a few of this +what I take to be the central themes of + + align:start position:0% +what I take to be the central themes of + + + align:start position:0% +what I take to be the central themes of +the course the the organizing ideas that + + align:start position:0% +the course the the organizing ideas that + + + align:start position:0% +the course the the organizing ideas that +that then at least have seemed to me to + + align:start position:0% +that then at least have seemed to me to + + + align:start position:0% +that then at least have seemed to me to +structure our our argument and our + + align:start position:0% +structure our our argument and our + + + align:start position:0% +structure our our argument and our +progress through these Oh through this + + align:start position:0% +progress through these Oh through this + + + align:start position:0% +progress through these Oh through this +almost a hundred years of movies the + + align:start position:0% +almost a hundred years of movies the + + + align:start position:0% +almost a hundred years of movies the +first idea at one that we've come back + + align:start position:0% +first idea at one that we've come back + + + align:start position:0% +first idea at one that we've come back +to I think again and again has to do + + align:start position:0% +to I think again and again has to do + + + align:start position:0% +to I think again and again has to do +with what we might call film in its + + align:start position:0% +with what we might call film in its + + + align:start position:0% +with what we might call film in its +anthropological or sociological aspect + + align:start position:0% +anthropological or sociological aspect + + + align:start position:0% +anthropological or sociological aspect +film as a cultural form as an expression + + align:start position:0% +film as a cultural form as an expression + + + align:start position:0% +film as a cultural form as an expression +of a culture as something that grows out + + align:start position:0% +of a culture as something that grows out + + + align:start position:0% +of a culture as something that grows out +of a culture that expresses the values + + align:start position:0% +of a culture that expresses the values + + + align:start position:0% +of a culture that expresses the values +and prejudices and weirdnesses of a + + align:start position:0% +and prejudices and weirdnesses of a + + + align:start position:0% +and prejudices and weirdnesses of a +culture from this angle questions of + + align:start position:0% +culture from this angle questions of + + + align:start position:0% +culture from this angle questions of +aesthetic value questions of artistic + + align:start position:0% +aesthetic value questions of artistic + + + align:start position:0% +aesthetic value questions of artistic +excellence are irrelevant in some sense + + align:start position:0% +excellence are irrelevant in some sense + + + align:start position:0% +excellence are irrelevant in some sense +within it from this angle we're thinking + + align:start position:0% +within it from this angle we're thinking + + + align:start position:0% +within it from this angle we're thinking +about film simply as a as a central + + align:start position:0% +about film simply as a as a central + + + align:start position:0% +about film simply as a as a central +expression as a central habit of culture + + align:start position:0% +expression as a central habit of culture + + + align:start position:0% +expression as a central habit of culture +itself and we might we might recognize + + align:start position:0% +itself and we might we might recognize + + + align:start position:0% +itself and we might we might recognize +that in the 20th century film where film + + align:start position:0% +that in the 20th century film where film + + + align:start position:0% +that in the 20th century film where film +was the dominant narrative form the film + + align:start position:0% +was the dominant narrative form the film + + + align:start position:0% +was the dominant narrative form the film +performed functions in the 20th century + + align:start position:0% +performed functions in the 20th century + + + align:start position:0% +performed functions in the 20th century +that earlier forms of storytelling of + + align:start position:0% +that earlier forms of storytelling of + + + align:start position:0% +that earlier forms of storytelling of +narrative and drama had played in + + align:start position:0% +narrative and drama had played in + + + align:start position:0% +narrative and drama had played in +earlier cultures and one of my deep + + align:start position:0% +earlier cultures and one of my deep + + + align:start position:0% +earlier cultures and one of my deep +desires in the course one of my implicit + + align:start position:0% +desires in the course one of my implicit + + + align:start position:0% +desires in the course one of my implicit +ambitions all the way through was to + + align:start position:0% +ambitions all the way through was to + + + align:start position:0% +ambitions all the way through was to +encourage you to think about movies in + + align:start position:0% +encourage you to think about movies in + + + align:start position:0% +encourage you to think about movies in +this way as an as a as as an expression + + align:start position:0% +this way as an as a as as an expression + + + align:start position:0% +this way as an as a as as an expression +of the values and assumptions of 20th + + align:start position:0% +of the values and assumptions of 20th + + + align:start position:0% +of the values and assumptions of 20th +century cultures which might in earlier + + align:start position:0% +century cultures which might in earlier + + + align:start position:0% +century cultures which might in earlier +times have been expressed in other media + + align:start position:0% +times have been expressed in other media + + + align:start position:0% +times have been expressed in other media +and was I it was important for me to + + align:start position:0% +and was I it was important for me to + + + align:start position:0% +and was I it was important for me to +have you recognize that our 20th and + + align:start position:0% +have you recognize that our 20th and + + + align:start position:0% +have you recognize that our 20th and +21st century although it's somewhat + + align:start position:0% +21st century although it's somewhat + + + align:start position:0% +21st century although it's somewhat +different in the 21st century because + + align:start position:0% +different in the 21st century because + + + align:start position:0% +different in the 21st century because +films are film is undergoing such a + + align:start position:0% +films are film is undergoing such a + + + align:start position:0% +films are film is undergoing such a +profound transformation in the digital + + align:start position:0% +profound transformation in the digital + + + align:start position:0% +profound transformation in the digital +age nonetheless in the 20th and the 21st + + align:start position:0% +age nonetheless in the 20th and the 21st + + + align:start position:0% +age nonetheless in the 20th and the 21st +century audio-visual narrative is a + + align:start position:0% +century audio-visual narrative is a + + + align:start position:0% +century audio-visual narrative is a +dominant experience for virtue + + align:start position:0% +dominant experience for virtue + + + align:start position:0% +dominant experience for virtue +everyone in the in the world in earlier + + align:start position:0% +everyone in the in the world in earlier + + + align:start position:0% +everyone in the in the world in earlier +societies we had didn't have this option + + align:start position:0% +societies we had didn't have this option + + + align:start position:0% +societies we had didn't have this option +but it didn't mean that the functions + + align:start position:0% +but it didn't mean that the functions + + + align:start position:0% +but it didn't mean that the functions +played by the movies weren't played by + + align:start position:0% +played by the movies weren't played by + + + align:start position:0% +played by the movies weren't played by +earlier forms so that's one of it that's + + align:start position:0% +earlier forms so that's one of it that's + + + align:start position:0% +earlier forms so that's one of it that's +been one of the deepest umph shion's one + + align:start position:0% +been one of the deepest umph shion's one + + + align:start position:0% +been one of the deepest umph shion's one +of the recurring principles to which + + align:start position:0% +of the recurring principles to which + + + align:start position:0% +of the recurring principles to which +I've recurred through the through the + + align:start position:0% +I've recurred through the through the + + + align:start position:0% +I've recurred through the through the +through the course and another aspect of + + align:start position:0% +through the course and another aspect of + + + align:start position:0% +through the course and another aspect of +this idea something I've come back to I + + align:start position:0% +this idea something I've come back to I + + + align:start position:0% +this idea something I've come back to I +think several times has been the + + align:start position:0% +think several times has been the + + + align:start position:0% +think several times has been the +relationship between storytelling and + + align:start position:0% +relationship between storytelling and + + + align:start position:0% +relationship between storytelling and +culture and what I've got drawing + + align:start position:0% +culture and what I've got drawing + + + align:start position:0% +culture and what I've got drawing +especially on certain anthropological + + align:start position:0% +especially on certain anthropological + + + align:start position:0% +especially on certain anthropological +and historical sources I've tried to + + align:start position:0% +and historical sources I've tried to + + + align:start position:0% +and historical sources I've tried to +suggest to you that one way of + + align:start position:0% +suggest to you that one way of + + + align:start position:0% +suggest to you that one way of +understanding culture itself is to + + align:start position:0% +understanding culture itself is to + + + align:start position:0% +understanding culture itself is to +understand culture through its stories + + align:start position:0% +understand culture through its stories + + + align:start position:0% +understand culture through its stories +is to understand that the stories our + + align:start position:0% +is to understand that the stories our + + + align:start position:0% +is to understand that the stories our +culture tells reveal the culture in + + align:start position:0% +culture tells reveal the culture in + + + align:start position:0% +culture tells reveal the culture in +basic ways not necessarily reveal the + + align:start position:0% +basic ways not necessarily reveal the + + + align:start position:0% +basic ways not necessarily reveal the +culture at its best although sometimes + + align:start position:0% +culture at its best although sometimes + + + align:start position:0% +culture at its best although sometimes +they may do so but they reveal the + + align:start position:0% +they may do so but they reveal the + + + align:start position:0% +they may do so but they reveal the +culture in powerful and central ways and + + align:start position:0% +culture in powerful and central ways and + + + align:start position:0% +culture in powerful and central ways and +some of our work in this course as I + + align:start position:0% +some of our work in this course as I + + + align:start position:0% +some of our work in this course as I +hope you recognize has been an attempt + + align:start position:0% +hope you recognize has been an attempt + + + align:start position:0% +hope you recognize has been an attempt +in some ways to to recover what might be + + align:start position:0% +in some ways to to recover what might be + + + align:start position:0% +in some ways to to recover what might be +called the cultural or the + + align:start position:0% +called the cultural or the + + + align:start position:0% +called the cultural or the +anthropological or the sociological + + align:start position:0% +anthropological or the sociological + + + align:start position:0% +anthropological or the sociological +assumptions and beliefs that are + + align:start position:0% +assumptions and beliefs that are + + + align:start position:0% +assumptions and beliefs that are +embedded in our movies one of the most + + align:start position:0% +embedded in our movies one of the most + + + align:start position:0% +embedded in our movies one of the most +important aspects of this principle of + + align:start position:0% +important aspects of this principle of + + + align:start position:0% +important aspects of this principle of +storytelling as intimately connected to + + align:start position:0% +storytelling as intimately connected to + + + align:start position:0% +storytelling as intimately connected to +the progress of culture has to do with + + align:start position:0% +the progress of culture has to do with + + + align:start position:0% +the progress of culture has to do with +an idea I suggested early in the term + + align:start position:0% +an idea I suggested early in the term + + + align:start position:0% +an idea I suggested early in the term +the idea that culture itself and this is + + align:start position:0% +the idea that culture itself and this is + + + align:start position:0% +the idea that culture itself and this is +one I think one of the great insights of + + align:start position:0% +one I think one of the great insights of + + + align:start position:0% +one I think one of the great insights of +20th century cultural history cultural + + align:start position:0% +20th century cultural history cultural + + + align:start position:0% +20th century cultural history cultural +analysis is the recognition that culture + + align:start position:0% +analysis is the recognition that culture + + + align:start position:0% +analysis is the recognition that culture +itself is a completely unfinished thing + + align:start position:0% +itself is a completely unfinished thing + + + align:start position:0% +itself is a completely unfinished thing +that it's never a single fixed item that + + align:start position:0% +that it's never a single fixed item that + + + align:start position:0% +that it's never a single fixed item that +culture itself is society itself is + + align:start position:0% +culture itself is society itself is + + + align:start position:0% +culture itself is society itself is +always in the process of evolving and + + align:start position:0% +always in the process of evolving and + + + align:start position:0% +always in the process of evolving and +changing that it's that its idea of + + align:start position:0% +changing that it's that its idea of + + + align:start position:0% +changing that it's that its idea of +itself is always in flux right this is + + align:start position:0% +itself is always in flux right this is + + + align:start position:0% +itself is always in flux right this is +an immensely productive way of + + align:start position:0% +an immensely productive way of + + + align:start position:0% +an immensely productive way of +understanding what society is because + + align:start position:0% +understanding what society is because + + + align:start position:0% +understanding what society is because +what it allows us to do is recognize + + align:start position:0% +what it allows us to do is recognize + + + align:start position:0% +what it allows us to do is recognize +that the various expressive and other + + align:start position:0% +that the various expressive and other + + + align:start position:0% +that the various expressive and other +especially the expressive forms of a + + align:start position:0% +especially the expressive forms of a + + + align:start position:0% +especially the expressive forms of a +culture play a central role in what we + + align:start position:0% +culture play a central role in what we + + + align:start position:0% +culture play a central role in what we +might call this ongoing attempt of + + align:start position:0% +might call this ongoing attempt of + + + align:start position:0% +might call this ongoing attempt of +scizor of a society to define and renew + + align:start position:0% +scizor of a society to define and renew + + + align:start position:0% +scizor of a society to define and renew +itself + + align:start position:0% +itself + + + align:start position:0% +itself +according to various values and + + align:start position:0% +according to various values and + + + align:start position:0% +according to various values and +assumptions and historical inheritances + + align:start position:0% +assumptions and historical inheritances + + + align:start position:0% +assumptions and historical inheritances +but also that the culture uses these + + align:start position:0% +but also that the culture uses these + + + align:start position:0% +but also that the culture uses these +stories as a way to react to + + align:start position:0% +stories as a way to react to + + + align:start position:0% +stories as a way to react to +disturbances and challenges to the + + align:start position:0% +disturbances and challenges to the + + + align:start position:0% +disturbances and challenges to the +social fabric they remember borrowing on + + align:start position:0% +social fabric they remember borrowing on + + + align:start position:0% +social fabric they remember borrowing on +the great English cultural historian + + align:start position:0% +the great English cultural historian + + + align:start position:0% +the great English cultural historian +Raymond Williams I suggested it in + + align:start position:0% +Raymond Williams I suggested it in + + + align:start position:0% +Raymond Williams I suggested it in +earlier course in earlier class that one + + align:start position:0% +earlier course in earlier class that one + + + align:start position:0% +earlier course in earlier class that one +of the ways to think about this process + + align:start position:0% +of the ways to think about this process + + + align:start position:0% +of the ways to think about this process +is to imagine culture itself as + + align:start position:0% +is to imagine culture itself as + + + align:start position:0% +is to imagine culture itself as +consisting of sort of three strands or + + align:start position:0% +consisting of sort of three strands or + + + align:start position:0% +consisting of sort of three strands or +voices an emerging voice which + + align:start position:0% +voices an emerging voice which + + + align:start position:0% +voices an emerging voice which +represents new ideas the future right + + align:start position:0% +represents new ideas the future right + + + align:start position:0% +represents new ideas the future right +emergent voices dominant or central + + align:start position:0% +emergent voices dominant or central + + + align:start position:0% +emergent voices dominant or central +voices where the central values of a + + align:start position:0% +voices where the central values of a + + + align:start position:0% +voices where the central values of a +society are embedded and articulated and + + align:start position:0% +society are embedded and articulated and + + + align:start position:0% +society are embedded and articulated and +on the other side what might be called + + align:start position:0% +on the other side what might be called + + + align:start position:0% +on the other side what might be called +traditional or vestige of voices the + + align:start position:0% +traditional or vestige of voices the + + + align:start position:0% +traditional or vestige of voices the +voices or energies that are losing force + + align:start position:0% +voices or energies that are losing force + + + align:start position:0% +voices or energies that are losing force +losing power as society changes that + + align:start position:0% +losing power as society changes that + + + align:start position:0% +losing power as society changes that +belong to a past but are still part of + + align:start position:0% +belong to a past but are still part of + + + align:start position:0% +belong to a past but are still part of +the mix and once we understand that + + align:start position:0% +the mix and once we understand that + + + align:start position:0% +the mix and once we understand that +culture is this constant sort of ongoing + + align:start position:0% +culture is this constant sort of ongoing + + + align:start position:0% +culture is this constant sort of ongoing +mixed conversation amongst traditional + + align:start position:0% +mixed conversation amongst traditional + + + align:start position:0% +mixed conversation amongst traditional +dominant and emergent voices we begin to + + align:start position:0% +dominant and emergent voices we begin to + + + align:start position:0% +dominant and emergent voices we begin to +understand much more about the + + align:start position:0% +understand much more about the + + + align:start position:0% +understand much more about the +complexity of how a culture but proceeds + + align:start position:0% +complexity of how a culture but proceeds + + + align:start position:0% +complexity of how a culture but proceeds +and it what and of course what this also + + align:start position:0% +and it what and of course what this also + + + align:start position:0% +and it what and of course what this also +does once we make the link between the + + align:start position:0% +does once we make the link between the + + + align:start position:0% +does once we make the link between the +stories of culture tells and the + + align:start position:0% +stories of culture tells and the + + + align:start position:0% +stories of culture tells and the +cultures idea of itself we can recognize + + align:start position:0% +cultures idea of itself we can recognize + + + align:start position:0% +cultures idea of itself we can recognize +that this same process can work for + + align:start position:0% +that this same process can work for + + + align:start position:0% +that this same process can work for +understanding stories it's immensely + + align:start position:0% +understanding stories it's immensely + + + align:start position:0% +understanding stories it's immensely +liberating immensely illuminating to + + align:start position:0% +liberating immensely illuminating to + + + align:start position:0% +liberating immensely illuminating to +recognize that of course films like + + align:start position:0% +recognize that of course films like + + + align:start position:0% +recognize that of course films like +other forms of narrative are going to + + align:start position:0% +other forms of narrative are going to + + + align:start position:0% +other forms of narrative are going to +contain elements that are not completely + + align:start position:0% +contain elements that are not completely + + + align:start position:0% +contain elements that are not completely +coherent not completely in agreement + + align:start position:0% +coherent not completely in agreement + + + align:start position:0% +coherent not completely in agreement +that they actually may sustain + + align:start position:0% +that they actually may sustain + + + align:start position:0% +that they actually may sustain +contradictions that that films that + + align:start position:0% +contradictions that that films that + + + align:start position:0% +contradictions that that films that +films like other forms of narrative may + + align:start position:0% +films like other forms of narrative may + + + align:start position:0% +films like other forms of narrative may +very well articulate both emergent and + + align:start position:0% +very well articulate both emergent and + + + align:start position:0% +very well articulate both emergent and +traditional voices and those those two + + align:start position:0% +traditional voices and those those two + + + align:start position:0% +traditional voices and those those two +voices may be in conflict or at least + + align:start position:0% +voices may be in conflict or at least + + + align:start position:0% +voices may be in conflict or at least +not in perfect coherence in a particular + + align:start position:0% +not in perfect coherence in a particular + + + align:start position:0% +not in perfect coherence in a particular +text so one of the advantages of this + + align:start position:0% +text so one of the advantages of this + + + align:start position:0% +text so one of the advantages of this +perspective is to allow us to recognize + + align:start position:0% +perspective is to allow us to recognize + + + align:start position:0% +perspective is to allow us to recognize +something of the complexity even the + + align:start position:0% +something of the complexity even the + + + align:start position:0% +something of the complexity even the +dynamic and potentially partly + + align:start position:0% +dynamic and potentially partly + + + align:start position:0% +dynamic and potentially partly +contradictory elements that we may find + + align:start position:0% +contradictory elements that we may find + + + align:start position:0% +contradictory elements that we may find +in particular films the idea that + + align:start position:0% +in particular films the idea that + + + align:start position:0% +in particular films the idea that +culture is always unfinished + + align:start position:0% +culture is always unfinished + + + align:start position:0% +culture is always unfinished +never a fixed or finished thing and that + + align:start position:0% +never a fixed or finished thing and that + + + align:start position:0% +never a fixed or finished thing and that +the stories of culture tells are a part + + align:start position:0% +the stories of culture tells are a part + + + align:start position:0% +the stories of culture tells are a part +of this ongoing conversation + + align:start position:0% +of this ongoing conversation + + + align:start position:0% +of this ongoing conversation +this dynamic always unfinished + + align:start position:0% +this dynamic always unfinished + + + align:start position:0% +this dynamic always unfinished +conversation about the values and + + align:start position:0% +conversation about the values and + + + align:start position:0% +conversation about the values and +assumptions the society lives by I + + align:start position:0% +assumptions the society lives by I + + + align:start position:0% +assumptions the society lives by I +suggested a number of times that one way + + align:start position:0% +suggested a number of times that one way + + + align:start position:0% +suggested a number of times that one way +to think about the central or the + + align:start position:0% +to think about the central or the + + + align:start position:0% +to think about the central or the +dominant narrative forms in particular + + align:start position:0% +dominant narrative forms in particular + + + align:start position:0% +dominant narrative forms in particular +cultures film in the 20th century the + + align:start position:0% +cultures film in the 20th century the + + + align:start position:0% +cultures film in the 20th century the +novel in the 18th and 19th century in + + align:start position:0% +novel in the 18th and 19th century in + + + align:start position:0% +novel in the 18th and 19th century in +certain European and America and in + + align:start position:0% +certain European and America and in + + + align:start position:0% +certain European and America and in +American society the Public Theater of + + align:start position:0% +American society the Public Theater of + + + align:start position:0% +American society the Public Theater of +Shakespeare's day the oral formulaic + + align:start position:0% +Shakespeare's day the oral formulaic + + + align:start position:0% +Shakespeare's day the oral formulaic +narrative in the ancient world of Homer + + align:start position:0% +narrative in the ancient world of Homer + + + align:start position:0% +narrative in the ancient world of Homer +and what I've suggested is that these + + align:start position:0% +and what I've suggested is that these + + + align:start position:0% +and what I've suggested is that these +narrative forms might be labeled can + + align:start position:0% +narrative forms might be labeled can + + + align:start position:0% +narrative forms might be labeled can +usefully be labeled as consensus forms + + align:start position:0% +usefully be labeled as consensus forms + + + align:start position:0% +usefully be labeled as consensus forms +because they understand themselves to + + align:start position:0% +because they understand themselves to + + + align:start position:0% +because they understand themselves to +occupy a central space in the society + + align:start position:0% +occupy a central space in the society + + + align:start position:0% +occupy a central space in the society +that they recognize not necessarily that + + align:start position:0% +that they recognize not necessarily that + + + align:start position:0% +that they recognize not necessarily that +they're expressing a true consensus no + + align:start position:0% +they're expressing a true consensus no + + + align:start position:0% +they're expressing a true consensus no +society has a perfect consensus but that + + align:start position:0% +society has a perfect consensus but that + + + align:start position:0% +society has a perfect consensus but that +what they recognize is that they're + + align:start position:0% +what they recognize is that they're + + + align:start position:0% +what they recognize is that they're +expressive they're expressing what is + + align:start position:0% +expressive they're expressing what is + + + align:start position:0% +expressive they're expressing what is +the imagined or the accepted or the or + + align:start position:0% +the imagined or the accepted or the or + + + align:start position:0% +the imagined or the accepted or the or +the presumed consensus of the culture + + align:start position:0% +the presumed consensus of the culture + + + align:start position:0% +the presumed consensus of the culture +that consensus of values may not be + + align:start position:0% +that consensus of values may not be + + + align:start position:0% +that consensus of values may not be +bought into by everyone certainly won't + + align:start position:0% +bought into by everyone certainly won't + + + align:start position:0% +bought into by everyone certainly won't +be nonetheless even the people who don't + + align:start position:0% +be nonetheless even the people who don't + + + align:start position:0% +be nonetheless even the people who don't +accept the consensus values recognize + + align:start position:0% +accept the consensus values recognize + + + align:start position:0% +accept the consensus values recognize +what the dominant values of the culture + + align:start position:0% +what the dominant values of the culture + + + align:start position:0% +what the dominant values of the culture +are and recognize those sites like the + + align:start position:0% +are and recognize those sites like the + + + align:start position:0% +are and recognize those sites like the +movies in the 20th century that are + + align:start position:0% +movies in the 20th century that are + + + align:start position:0% +movies in the 20th century that are +carriers of what we might call that + + align:start position:0% +carriers of what we might call that + + + align:start position:0% +carriers of what we might call that +official or consensus meaning and one of + + align:start position:0% +official or consensus meaning and one of + + + align:start position:0% +official or consensus meaning and one of +the things I tried to suggest to you in + + align:start position:0% +the things I tried to suggest to you in + + + align:start position:0% +the things I tried to suggest to you in +the in the course of our our discussions + + align:start position:0% +the in the course of our our discussions + + + align:start position:0% +the in the course of our our discussions +is the way in which in the 20th century + + align:start position:0% +is the way in which in the 20th century + + + align:start position:0% +is the way in which in the 20th century +form of film the way the central role + + align:start position:0% +form of film the way the central role + + + align:start position:0% +form of film the way the central role +that genre forms play in this process + + align:start position:0% +that genre forms play in this process + + + align:start position:0% +that genre forms play in this process +right the way and can you see why that + + align:start position:0% +right the way and can you see why that + + + align:start position:0% +right the way and can you see why that +would be true one reason is that there's + + align:start position:0% +would be true one reason is that there's + + + align:start position:0% +would be true one reason is that there's +an implicit in there's an implicit + + align:start position:0% +an implicit in there's an implicit + + + align:start position:0% +an implicit in there's an implicit +principle of repetition within variation + + align:start position:0% +principle of repetition within variation + + + align:start position:0% +principle of repetition within variation +in genre forms because they're so + + align:start position:0% +in genre forms because they're so + + + align:start position:0% +in genre forms because they're so +familiar the different as one as a late + + align:start position:0% +familiar the different as one as a late + + + align:start position:0% +familiar the different as one as a late +Western and an early Western might be + + align:start position:0% +Western and an early Western might be + + + align:start position:0% +Western and an early Western might be +they're still westerns and they share a + + align:start position:0% +they're still westerns and they share a + + + align:start position:0% +they're still westerns and they share a +great deal right they share certain + + align:start position:0% +great deal right they share certain + + + align:start position:0% +great deal right they share certain +fundamental qualities that that every + + align:start position:0% +fundamental qualities that that every + + + align:start position:0% +fundamental qualities that that every +viewer recognizes the more literate the + + align:start position:0% +viewer recognizes the more literate the + + + align:start position:0% +viewer recognizes the more literate the +viewer or the reader is in the + + align:start position:0% +viewer or the reader is in the + + + align:start position:0% +viewer or the reader is in the +conventions of a particular genre the + + align:start position:0% +conventions of a particular genre the + + + align:start position:0% +conventions of a particular genre the +chair the uses of that genre become + + align:start position:0% +chair the uses of that genre become + + + align:start position:0% +chair the uses of that genre become +especially as the genre elaborates + + align:start position:0% +especially as the genre elaborates + + + align:start position:0% +especially as the genre elaborates +itself over time and one of the things I + + align:start position:0% +itself over time and one of the things I + + + align:start position:0% +itself over time and one of the things I +tried to show you by talking especially + + align:start position:0% +tried to show you by talking especially + + + align:start position:0% +tried to show you by talking especially +about the Western in American society + + align:start position:0% +about the Western in American society + + + align:start position:0% +about the Western in American society +was to suggest that we can actually + + align:start position:0% +was to suggest that we can actually + + + align:start position:0% +was to suggest that we can actually +understand some of these genre forms as + + align:start position:0% +understand some of these genre forms as + + + align:start position:0% +understand some of these genre forms as +in some sense mirroring the debate of + + align:start position:0% +in some sense mirroring the debate of + + + align:start position:0% +in some sense mirroring the debate of +society may very well be having about + + align:start position:0% +society may very well be having about + + + align:start position:0% +society may very well be having about +its own nature and that the way the + + align:start position:0% +its own nature and that the way the + + + align:start position:0% +its own nature and that the way the +Western changes over time you know in in + + align:start position:0% +Western changes over time you know in in + + + align:start position:0% +Western changes over time you know in in +in the history of film is a kind of + + align:start position:0% +in the history of film is a kind of + + + align:start position:0% +in the history of film is a kind of +distillation of this process whereby the + + align:start position:0% +distillation of this process whereby the + + + align:start position:0% +distillation of this process whereby the +stories of a culture helped the story + + align:start position:0% +stories of a culture helped the story + + + align:start position:0% +stories of a culture helped the story +help the culture to accommodate itself + + align:start position:0% +help the culture to accommodate itself + + + align:start position:0% +help the culture to accommodate itself +to changes help them help the culture + + align:start position:0% +to changes help them help the culture + + + align:start position:0% +to changes help them help the culture +figure out how its past and its present + + align:start position:0% +figure out how its past and its present + + + align:start position:0% +figure out how its past and its present +can be brought into some kind of + + align:start position:0% +can be brought into some kind of + + + align:start position:0% +can be brought into some kind of +relation help that help the society get + + align:start position:0% +relation help that help the society get + + + align:start position:0% +relation help that help the society get +used to change and dynamic challenges to + + align:start position:0% +used to change and dynamic challenges to + + + align:start position:0% +used to change and dynamic challenges to +its to its coherence one implication of + + align:start position:0% +its to its coherence one implication of + + + align:start position:0% +its to its coherence one implication of +the of the kind of argument I've been + + align:start position:0% +the of the kind of argument I've been + + + align:start position:0% +the of the kind of argument I've been +making about consensus narrative as I've + + align:start position:0% +making about consensus narrative as I've + + + align:start position:0% +making about consensus narrative as I've +suggested a number of times is that + + align:start position:0% +suggested a number of times is that + + + align:start position:0% +suggested a number of times is that +consensus narrative always what I'm + + align:start position:0% +consensus narrative always what I'm + + + align:start position:0% +consensus narrative always what I'm +calling consensus narrative we might use + + align:start position:0% +calling consensus narrative we might use + + + align:start position:0% +calling consensus narrative we might use +a simpler and less aggressive term we + + align:start position:0% +a simpler and less aggressive term we + + + align:start position:0% +a simpler and less aggressive term we +might say various forms of popular + + align:start position:0% +might say various forms of popular + + + align:start position:0% +might say various forms of popular +culture share the same qualities with + + align:start position:0% +culture share the same qualities with + + + align:start position:0% +culture share the same qualities with +with the particular form of popular + + align:start position:0% +with the particular form of popular + + + align:start position:0% +with the particular form of popular +culture I'm calling consensus narrative + + align:start position:0% +culture I'm calling consensus narrative + + + align:start position:0% +culture I'm calling consensus narrative +and remember one of the exciting things + + align:start position:0% +and remember one of the exciting things + + + align:start position:0% +and remember one of the exciting things +about this concept is it shifts from + + align:start position:0% +about this concept is it shifts from + + + align:start position:0% +about this concept is it shifts from +moment - from a culture to culture or + + align:start position:0% +moment - from a culture to culture or + + + align:start position:0% +moment - from a culture to culture or +from era to era the consensus narrative + + align:start position:0% +from era to era the consensus narrative + + + align:start position:0% +from era to era the consensus narrative +system of one society won't be the same + + align:start position:0% +system of one society won't be the same + + + align:start position:0% +system of one society won't be the same +as that of another Society but the + + align:start position:0% +as that of another Society but the + + + align:start position:0% +as that of another Society but the +systems will share certain in one case + + align:start position:0% +systems will share certain in one case + + + align:start position:0% +systems will share certain in one case +it might be the novel in another case it + + align:start position:0% +it might be the novel in another case it + + + align:start position:0% +it might be the novel in another case it +might be the film but both systems will + + align:start position:0% +might be the film but both systems will + + + align:start position:0% +might be the film but both systems will +both both of these forms when there are + + align:start position:0% +both both of these forms when there are + + + align:start position:0% +both both of these forms when there are +consensus system consensus forms will + + align:start position:0% +consensus system consensus forms will + + + align:start position:0% +consensus system consensus forms will +share certain qualities and I've + + align:start position:0% +share certain qualities and I've + + + align:start position:0% +share certain qualities and I've +suggested that the central qualities + + align:start position:0% +suggested that the central qualities + + + align:start position:0% +suggested that the central qualities +they would they share are that they are + + align:start position:0% +they would they share are that they are + + + align:start position:0% +they would they share are that they are +always in some deep way conservative + + align:start position:0% +always in some deep way conservative + + + align:start position:0% +always in some deep way conservative +right they're both morally conservative + + align:start position:0% +right they're both morally conservative + + + align:start position:0% +right they're both morally conservative +or or conservative in terms of content + + align:start position:0% +or or conservative in terms of content + + + align:start position:0% +or or conservative in terms of content +because they're trying to reach the + + align:start position:0% +because they're trying to reach the + + + align:start position:0% +because they're trying to reach the +whole of the society and they have to be + + align:start position:0% +whole of the society and they have to be + + + align:start position:0% +whole of the society and they have to be +careful about that they can't be as + + align:start position:0% +careful about that they can't be as + + + align:start position:0% +careful about that they can't be as +advanced or as radical as the most + + align:start position:0% +advanced or as radical as the most + + + align:start position:0% +advanced or as radical as the most +radical or or avant-garde parts of the + + align:start position:0% +radical or or avant-garde parts of the + + + align:start position:0% +radical or or avant-garde parts of the +culture because certain elements of the + + align:start position:0% +culture because certain elements of the + + + align:start position:0% +culture because certain elements of the +culture would be alienated by it and + + align:start position:0% +culture would be alienated by it and + + + align:start position:0% +culture would be alienated by it and +it's the cultural + + align:start position:0% +it's the cultural + + + align:start position:0% +it's the cultural +work of consensus narrative to address + + align:start position:0% +work of consensus narrative to address + + + align:start position:0% +work of consensus narrative to address +the center of society right so they're + + align:start position:0% +the center of society right so they're + + + align:start position:0% +the center of society right so they're +conservative in content and in moral + + align:start position:0% +conservative in content and in moral + + + align:start position:0% +conservative in content and in moral +values and they're also conservative + + align:start position:0% +values and they're also conservative + + + align:start position:0% +values and they're also conservative +artistically that is to say they don't + + align:start position:0% +artistically that is to say they don't + + + align:start position:0% +artistically that is to say they don't +do a lot of sort of daring and and + + align:start position:0% +do a lot of sort of daring and and + + + align:start position:0% +do a lot of sort of daring and and +shocking technical or structural + + align:start position:0% +shocking technical or structural + + + align:start position:0% +shocking technical or structural +experiments again because they want to + + align:start position:0% +experiments again because they want to + + + align:start position:0% +experiments again because they want to +be because they aim to be understood by + + align:start position:0% +be because they aim to be understood by + + + align:start position:0% +be because they aim to be understood by +a large proportion of the population + + align:start position:0% +a large proportion of the population + + + align:start position:0% +a large proportion of the population +they aim to be readable by everyone and + + align:start position:0% +they aim to be readable by everyone and + + + align:start position:0% +they aim to be readable by everyone and +that brings us to to a second item + + align:start position:0% +that brings us to to a second item + + + align:start position:0% +that brings us to to a second item +that's an aspect of always a fundamental + + align:start position:0% +that's an aspect of always a fundamental + + + align:start position:0% +that's an aspect of always a fundamental +aspect of consensus narrative that + + align:start position:0% +aspect of consensus narrative that + + + align:start position:0% +aspect of consensus narrative that +they're accessible that they are written + + align:start position:0% +they're accessible that they are written + + + align:start position:0% +they're accessible that they are written +in or or created in a you know language + + align:start position:0% +in or or created in a you know language + + + align:start position:0% +in or or created in a you know language +according to printing to archetypes or + + align:start position:0% +according to printing to archetypes or + + + align:start position:0% +according to printing to archetypes or +stereotypes or shared tropes and and and + + align:start position:0% +stereotypes or shared tropes and and and + + + align:start position:0% +stereotypes or shared tropes and and and +conventions that are accessible readable + + align:start position:0% +conventions that are accessible readable + + + align:start position:0% +conventions that are accessible readable +to the whole of the society and a final + + align:start position:0% +to the whole of the society and a final + + + align:start position:0% +to the whole of the society and a final +feature that these texts always have is + + align:start position:0% +feature that these texts always have is + + + align:start position:0% +feature that these texts always have is +that they are collaborative that is to + + align:start position:0% +that they are collaborative that is to + + + align:start position:0% +that they are collaborative that is to +say and I and I've suggested earlier in + + align:start position:0% +say and I and I've suggested earlier in + + + align:start position:0% +say and I and I've suggested earlier in +the course that one way to think about + + align:start position:0% +the course that one way to think about + + + align:start position:0% +the course that one way to think about +how collaborative the movies are is to + + align:start position:0% +how collaborative the movies are is to + + + align:start position:0% +how collaborative the movies are is to +recognize that every movie is itself a + + align:start position:0% +recognize that every movie is itself a + + + align:start position:0% +recognize that every movie is itself a +collaboration that you can't make a + + align:start position:0% +collaboration that you can't make a + + + align:start position:0% +collaboration that you can't make a +movie one person can never make a movie + + align:start position:0% +movie one person can never make a movie + + + align:start position:0% +movie one person can never make a movie +that a movie is always a collaborative + + align:start position:0% +that a movie is always a collaborative + + + align:start position:0% +that a movie is always a collaborative +form but but I mean that this idea of + + align:start position:0% +form but but I mean that this idea of + + + align:start position:0% +form but but I mean that this idea of +collaboration in a deeper way as well + + align:start position:0% +collaboration in a deeper way as well + + + align:start position:0% +collaboration in a deeper way as well +not only is the text are the texts of + + align:start position:0% +not only is the text are the texts of + + + align:start position:0% +not only is the text are the texts of +movies than literally collaborative + + align:start position:0% +movies than literally collaborative + + + align:start position:0% +movies than literally collaborative +great collaboratively created by many + + align:start position:0% +great collaboratively created by many + + + align:start position:0% +great collaboratively created by many +many creators but their collaborative in + + align:start position:0% +many creators but their collaborative in + + + align:start position:0% +many creators but their collaborative in +another way and LA in a deep way and of + + align:start position:0% +another way and LA in a deep way and of + + + align:start position:0% +another way and LA in a deep way and of +course the most obvious one is the way + + align:start position:0% +course the most obvious one is the way + + + align:start position:0% +course the most obvious one is the way +in which Yan reforms + + align:start position:0% +in which Yan reforms + + + align:start position:0% +in which Yan reforms +collaborate with themselves the way + + align:start position:0% +collaborate with themselves the way + + + align:start position:0% +collaborate with themselves the way +they're in a kind of conversation with + + align:start position:0% +they're in a kind of conversation with + + + align:start position:0% +they're in a kind of conversation with +all prior instances of the genre that's + + align:start position:0% +all prior instances of the genre that's + + + align:start position:0% +all prior instances of the genre that's +a full and that what that means is that + + align:start position:0% +a full and that what that means is that + + + align:start position:0% +a full and that what that means is that +Yan reforms are collaborating with their + + align:start position:0% +Yan reforms are collaborating with their + + + align:start position:0% +Yan reforms are collaborating with their +history they're collaborating with their + + align:start position:0% +history they're collaborating with their + + + align:start position:0% +history they're collaborating with their +path and they're also implicitly + + align:start position:0% +path and they're also implicitly + + + align:start position:0% +path and they're also implicitly +collaborating with the audience's + + align:start position:0% +collaborating with the audience's + + + align:start position:0% +collaborating with the audience's +literate knowledge of what these genre + + align:start position:0% +literate knowledge of what these genre + + + align:start position:0% +literate knowledge of what these genre +forms are like how they behave what the + + align:start position:0% +forms are like how they behave what the + + + align:start position:0% +forms are like how they behave what the +expectations and the more and their + + align:start position:0% +expectations and the more and their + + + align:start position:0% +expectations and the more and their +collaborative in yet another way and and + + align:start position:0% +collaborative in yet another way and and + + + align:start position:0% +collaborative in yet another way and and +and this this aspect of their + + align:start position:0% +and this this aspect of their + + + align:start position:0% +and this this aspect of their +collaborative character is one that I + + align:start position:0% +collaborative character is one that I + + + align:start position:0% +collaborative character is one that I +haven't emphasized too much and I want + + align:start position:0% +haven't emphasized too much and I want + + + align:start position:0% +haven't emphasized too much and I want +to do it + + align:start position:0% +to do it + + + align:start position:0% +to do it +today in our in our final in our + + align:start position:0% +today in our in our final in our + + + align:start position:0% +today in our in our final in our +farewell lecture their collaborative + + align:start position:0% +farewell lecture their collaborative + + + align:start position:0% +farewell lecture their collaborative +also because these texts in some deep + + align:start position:0% +also because these texts in some deep + + + align:start position:0% +also because these texts in some deep +way are collaborating with what we might + + align:start position:0% +way are collaborating with what we might + + + align:start position:0% +way are collaborating with what we might +call the collective wisdom or values of + + align:start position:0% +call the collective wisdom or values of + + + align:start position:0% +call the collective wisdom or values of +the culture right and that this is + + align:start position:0% +the culture right and that this is + + + align:start position:0% +the culture right and that this is +implicit in what I've been saying + + align:start position:0% +implicit in what I've been saying + + + align:start position:0% +implicit in what I've been saying +about the way these story forms draw on + + align:start position:0% +about the way these story forms draw on + + + align:start position:0% +about the way these story forms draw on +the histories and stories and + + align:start position:0% +the histories and stories and + + + align:start position:0% +the histories and stories and +conventions that are most widely shared + + align:start position:0% +conventions that are most widely shared + + + align:start position:0% +conventions that are most widely shared +and in a culture but I want to clarify + + align:start position:0% +and in a culture but I want to clarify + + + align:start position:0% +and in a culture but I want to clarify +what I mean by it so there's that kind + + align:start position:0% +what I mean by it so there's that kind + + + align:start position:0% +what I mean by it so there's that kind +of collaboration in which they're + + align:start position:0% +of collaboration in which they're + + + align:start position:0% +of collaboration in which they're +constantly borrowing forms and arguments + + align:start position:0% +constantly borrowing forms and arguments + + + align:start position:0% +constantly borrowing forms and arguments +and principles and symbols from the vast + + align:start position:0% +and principles and symbols from the vast + + + align:start position:0% +and principles and symbols from the vast +body of shared knowledge that a culture + + align:start position:0% +body of shared knowledge that a culture + + + align:start position:0% +body of shared knowledge that a culture +might have and so that but what this + + align:start position:0% +might have and so that but what this + + + align:start position:0% +might have and so that but what this +might actually lead to or some what one + + align:start position:0% +might actually lead to or some what one + + + align:start position:0% +might actually lead to or some what one +thing this leads to is the recognition + + align:start position:0% +thing this leads to is the recognition + + + align:start position:0% +thing this leads to is the recognition +that these cultural forms are not always + + align:start position:0% +that these cultural forms are not always + + + align:start position:0% +that these cultural forms are not always +Noble or wonderful that they carry + + align:start position:0% +Noble or wonderful that they carry + + + align:start position:0% +Noble or wonderful that they carry +prejudices that they carry racism that + + align:start position:0% +prejudices that they carry racism that + + + align:start position:0% +prejudices that they carry racism that +they carry misogyny that they're going + + align:start position:0% +they carry misogyny that they're going + + + align:start position:0% +they carry misogyny that they're going +to embody that that that the that the + + align:start position:0% +to embody that that that the that the + + + align:start position:0% +to embody that that that the that the +study of these Texas not as necessarily + + align:start position:0% +study of these Texas not as necessarily + + + align:start position:0% +study of these Texas not as necessarily +it shouldn't that never should be a + + align:start position:0% +it shouldn't that never should be a + + + align:start position:0% +it shouldn't that never should be a +totally celebratory experience even + + align:start position:0% +totally celebratory experience even + + + align:start position:0% +totally celebratory experience even +though many of these texts are want + + align:start position:0% +though many of these texts are want + + + align:start position:0% +though many of these texts are want +valuable and lasting and and speak to us + + align:start position:0% +valuable and lasting and and speak to us + + + align:start position:0% +valuable and lasting and and speak to us +in deep and powerful and useful ways + + align:start position:0% +in deep and powerful and useful ways + + + align:start position:0% +in deep and powerful and useful ways +it's also true that these texts carry + + align:start position:0% +it's also true that these texts carry + + + align:start position:0% +it's also true that these texts carry +the lies and prejudices of the cultures + + align:start position:0% +the lies and prejudices of the cultures + + + align:start position:0% +the lies and prejudices of the cultures +from which they come as I've said a + + align:start position:0% +from which they come as I've said a + + + align:start position:0% +from which they come as I've said a +number of times in the course perhaps + + align:start position:0% +number of times in the course perhaps + + + align:start position:0% +number of times in the course perhaps +too many times but there's a nut but I + + align:start position:0% +too many times but there's a nut but I + + + align:start position:0% +too many times but there's a nut but I +meant but I mentioned again in in this + + align:start position:0% +meant but I mentioned again in in this + + + align:start position:0% +meant but I mentioned again in in this +last lecture because I want to also + + align:start position:0% +last lecture because I want to also + + + align:start position:0% +last lecture because I want to also +mention that there's a way in which not + + align:start position:0% +mention that there's a way in which not + + + align:start position:0% +mention that there's a way in which not +just the evils and the limitations of a + + align:start position:0% +just the evils and the limitations of a + + + align:start position:0% +just the evils and the limitations of a +society that get expressed in the in the + + align:start position:0% +society that get expressed in the in the + + + align:start position:0% +society that get expressed in the in the +color in the in the collaborative + + align:start position:0% +color in the in the collaborative + + + align:start position:0% +color in the in the collaborative +consensus forms that emerge from them + + align:start position:0% +consensus forms that emerge from them + + + align:start position:0% +consensus forms that emerge from them +but also sometimes the wisdom of a + + align:start position:0% +but also sometimes the wisdom of a + + + align:start position:0% +but also sometimes the wisdom of a +society does - in other words what I + + align:start position:0% +society does - in other words what I + + + align:start position:0% +society does - in other words what I +want to suggest you is that the + + align:start position:0% +want to suggest you is that the + + + align:start position:0% +want to suggest you is that the +collaboration has to do not only with + + align:start position:0% +collaboration has to do not only with + + + align:start position:0% +collaboration has to do not only with +with with inherited values and inherited + + align:start position:0% +with with inherited values and inherited + + + align:start position:0% +with with inherited values and inherited +beliefs and inherited story forms they + + align:start position:0% +beliefs and inherited story forms they + + + align:start position:0% +beliefs and inherited story forms they +also have they also have to do sort of + + align:start position:0% +also have they also have to do sort of + + + align:start position:0% +also have they also have to do sort of +with a cut whether with a cut with the + + align:start position:0% +with a cut whether with a cut with the + + + align:start position:0% +with a cut whether with a cut with the +kind of inheritance of them of wisdom + + align:start position:0% +kind of inheritance of them of wisdom + + + align:start position:0% +kind of inheritance of them of wisdom +and I have a particularly exciting way + + align:start position:0% +and I have a particularly exciting way + + + align:start position:0% +and I have a particularly exciting way +of distilling this for you there's a + + align:start position:0% +of distilling this for you there's a + + + align:start position:0% +of distilling this for you there's a +passage one of my favorite passages from + + align:start position:0% +passage one of my favorite passages from + + + align:start position:0% +passage one of my favorite passages from +Shakespeare from his from his great late + + align:start position:0% +Shakespeare from his from his great late + + + align:start position:0% +Shakespeare from his from his great late +play Cymbeline from act 4 + + align:start position:0% +play Cymbeline from act 4 + + + align:start position:0% +play Cymbeline from act 4 +- in which a group of characters gather + + align:start position:0% +- in which a group of characters gather + + + align:start position:0% +- in which a group of characters gather +around a body they think the body + + align:start position:0% +around a body they think the body + + + align:start position:0% +around a body they think the body +actually comes alive later in the play + + align:start position:0% +actually comes alive later in the play + + + align:start position:0% +actually comes alive later in the play +because there's a lot of wonderful magic + + align:start position:0% +because there's a lot of wonderful magic + + + align:start position:0% +because there's a lot of wonderful magic +in the play it's a play about Redemption + + align:start position:0% +in the play it's a play about Redemption + + + align:start position:0% +in the play it's a play about Redemption +and rebirth but at this moment in the + + align:start position:0% +and rebirth but at this moment in the + + + align:start position:0% +and rebirth but at this moment in the +play they think this person is dead and + + align:start position:0% +play they think this person is dead and + + + align:start position:0% +play they think this person is dead and +they sing a dirge it's one of the most + + align:start position:0% +they sing a dirge it's one of the most + + + align:start position:0% +they sing a dirge it's one of the most +uh dirt assault a funeral song a song a + + align:start position:0% +uh dirt assault a funeral song a song a + + + align:start position:0% +uh dirt assault a funeral song a song a +song or a poem to be sung or recited at + + align:start position:0% +song or a poem to be sung or recited at + + + align:start position:0% +song or a poem to be sung or recited at +a graveside and there's a maybe the + + align:start position:0% +a graveside and there's a maybe the + + + align:start position:0% +a graveside and there's a maybe the +greatest of all such churches in English + + align:start position:0% +greatest of all such churches in English + + + align:start position:0% +greatest of all such churches in English +is in Cymbeline and this is the first + + align:start position:0% +is in Cymbeline and this is the first + + + align:start position:0% +is in Cymbeline and this is the first +stanza and the greatest stanza + + align:start position:0% +stanza and the greatest stanza + + + align:start position:0% +stanza and the greatest stanza +fear no more right there people are + + align:start position:0% +fear no more right there people are + + + align:start position:0% +fear no more right there people are +standing over a corpse right fear no + + align:start position:0% +standing over a corpse right fear no + + + align:start position:0% +standing over a corpse right fear no +more the heat of the Sun nor the Furious + + align:start position:0% +more the heat of the Sun nor the Furious + + + align:start position:0% +more the heat of the Sun nor the Furious +winters rages val by worldly tasks hath + + align:start position:0% +winters rages val by worldly tasks hath + + + align:start position:0% +winters rages val by worldly tasks hath +done home art gone and taken thy wages + + align:start position:0% +done home art gone and taken thy wages + + + align:start position:0% +done home art gone and taken thy wages +very interesting to me - to image to + + align:start position:0% +very interesting to me - to image to + + + align:start position:0% +very interesting to me - to image to +embrace a metaphor of working of were a + + align:start position:0% +embrace a metaphor of working of were a + + + align:start position:0% +embrace a metaphor of working of were a +working-class metaphor right you've got + + align:start position:0% +working-class metaphor right you've got + + + align:start position:0% +working-class metaphor right you've got +you're dying when and the metaphor is + + align:start position:0% +you're dying when and the metaphor is + + + align:start position:0% +you're dying when and the metaphor is +you've taken I what you you've taken + + align:start position:0% +you've taken I what you you've taken + + + align:start position:0% +you've taken I what you you've taken +your last wages you've finished your + + align:start position:0% +your last wages you've finished your + + + align:start position:0% +your last wages you've finished your +your work home art gone and taking my + + align:start position:0% +your work home art gone and taking my + + + align:start position:0% +your work home art gone and taking my +wages and here comes the couplet that I + + align:start position:0% +wages and here comes the couplet that I + + + align:start position:0% +wages and here comes the couplet that I +think is most powerful golden lads and + + align:start position:0% +think is most powerful golden lads and + + + align:start position:0% +think is most powerful golden lads and +girls all must as chimney sweepers come + + align:start position:0% +girls all must as chimney sweepers come + + + align:start position:0% +girls all must as chimney sweepers come +to dust let me say it again so you get + + align:start position:0% +to dust let me say it again so you get + + + align:start position:0% +to dust let me say it again so you get +the whole stanza it's quite beautiful I + + align:start position:0% +the whole stanza it's quite beautiful I + + + align:start position:0% +the whole stanza it's quite beautiful I +think fear no more the heat of the Sun + + align:start position:0% +think fear no more the heat of the Sun + + + align:start position:0% +think fear no more the heat of the Sun +nor the Furious winters rages thou thy + + align:start position:0% +nor the Furious winters rages thou thy + + + align:start position:0% +nor the Furious winters rages thou thy +worldly task hath done home art gone and + + align:start position:0% +worldly task hath done home art gone and + + + align:start position:0% +worldly task hath done home art gone and +taken thy wages golden lads and girls + + align:start position:0% +taken thy wages golden lads and girls + + + align:start position:0% +taken thy wages golden lads and girls +all must as chimney sweepers come to + + align:start position:0% +all must as chimney sweepers come to + + + align:start position:0% +all must as chimney sweepers come to +dust now think about those last lines + + align:start position:0% +dust now think about those last lines + + + align:start position:0% +dust now think about those last lines +for a minute they're very powerful even + + align:start position:0% +for a minute they're very powerful even + + + align:start position:0% +for a minute they're very powerful even +if you don't exactly get them golden + + align:start position:0% +if you don't exactly get them golden + + + align:start position:0% +if you don't exactly get them golden +lads and girls right + + align:start position:0% +lads and girls right + + + align:start position:0% +lads and girls right +the implication is highborn wealthy + + align:start position:0% + + + + align:start position:0% + +golden in their youth and in their + + align:start position:0% +golden in their youth and in their + + + align:start position:0% +golden in their youth and in their +energy and in their and in their and + + align:start position:0% +energy and in their and in their and + + + align:start position:0% +energy and in their and in their and +then in their vitality no matter how + + align:start position:0% +then in their vitality no matter how + + + align:start position:0% +then in their vitality no matter how +golden whether in wealth or in vitality + + align:start position:0% +golden whether in wealth or in vitality + + + align:start position:0% +golden whether in wealth or in vitality +even even golden golden lads and girls + + align:start position:0% +even even golden golden lads and girls + + + align:start position:0% +even even golden golden lads and girls +end up in the grave like all of us and + + align:start position:0% +end up in the grave like all of us and + + + align:start position:0% +end up in the grave like all of us and +there's a the implication of course is + + align:start position:0% +there's a the implication of course is + + + align:start position:0% +there's a the implication of course is +there's a kind of consolation in the + + align:start position:0% +there's a kind of consolation in the + + + align:start position:0% +there's a kind of consolation in the +fact that its death is our shared fate + + align:start position:0% +fact that its death is our shared fate + + + align:start position:0% +fact that its death is our shared fate +there's a it's a console an attempt to + + align:start position:0% +there's a it's a console an attempt to + + + align:start position:0% +there's a it's a console an attempt to +console us although the older I get the + + align:start position:0% +console us although the older I get the + + + align:start position:0% +console us although the older I get the +less consolation they get but I I find + + align:start position:0% +less consolation they get but I I find + + + align:start position:0% +less consolation they get but I I find +myself taking from this insight + + align:start position:0% +myself taking from this insight + + + align:start position:0% +myself taking from this insight +nonetheless it is a great poem and the + + align:start position:0% +nonetheless it is a great poem and the + + + align:start position:0% +nonetheless it is a great poem and the +stanza is a particularly remarkable poem + + align:start position:0% +stanza is a particularly remarkable poem + + + align:start position:0% +stanza is a particularly remarkable poem +because of one element in it + + align:start position:0% +because of one element in it + + + align:start position:0% +because of one element in it +the phrase golden lads for those of you + + align:start position:0% +the phrase golden lads for those of you + + + align:start position:0% +the phrase golden lads for those of you +very few Americans know this but some + + align:start position:0% +very few Americans know this but some + + + align:start position:0% +very few Americans know this but some +Brits know this + + align:start position:0% +Brits know this + + + align:start position:0% +Brits know this +in Shakespeare's native Warwickshire the + + align:start position:0% +in Shakespeare's native Warwickshire the + + + align:start position:0% +in Shakespeare's native Warwickshire the +phrase golden lad referred to something + + align:start position:0% +phrase golden lad referred to something + + + align:start position:0% +phrase golden lad referred to something +very specific it referred to the + + align:start position:0% +very specific it referred to the + + + align:start position:0% +very specific it referred to the +condition of the common ordinary flower + + align:start position:0% +condition of the common ordinary flower + + + align:start position:0% +condition of the common ordinary flower +that we call the dandelion and it's a + + align:start position:0% +that we call the dandelion and it's a + + + align:start position:0% +that we call the dandelion and it's a +it's a flower that that that has a gold + + align:start position:0% +it's a flower that that that has a gold + + + align:start position:0% +it's a flower that that that has a gold +cap when it's when it's young and then + + align:start position:0% +cap when it's when it's young and then + + + align:start position:0% +cap when it's when it's young and then +when it goes to seed and you've all seen + + align:start position:0% +when it goes to seed and you've all seen + + + align:start position:0% +when it goes to seed and you've all seen +them because they're native to North + + align:start position:0% +them because they're native to North + + + align:start position:0% +them because they're native to North +America as well as England they're the + + align:start position:0% +America as well as England they're the + + + align:start position:0% +America as well as England they're the +the top of the cap + + align:start position:0% +the top of the cap + + + align:start position:0% +the top of the cap +turns into a kind of rounded series of + + align:start position:0% +turns into a kind of rounded series of + + + align:start position:0% +turns into a kind of rounded series of +filaments a beautiful round cap and get + + align:start position:0% +filaments a beautiful round cap and get + + + align:start position:0% +filaments a beautiful round cap and get +when when you're a lot of children pick + + align:start position:0% +when when you're a lot of children pick + + + align:start position:0% +when when you're a lot of children pick +them and blow them and you could the + + align:start position:0% +them and blow them and you could the + + + align:start position:0% +them and blow them and you could the +seeds blow although one of the reasons + + align:start position:0% +seeds blow although one of the reasons + + + align:start position:0% +seeds blow although one of the reasons +that these that these common weedy + + align:start position:0% +that these that these common weedy + + + align:start position:0% +that these that these common weedy +flowers are so common is that they're so + + align:start position:0% +flowers are so common is that they're so + + + align:start position:0% +flowers are so common is that they're so +they're so brilliantly designed by + + align:start position:0% +they're so brilliantly designed by + + + align:start position:0% +they're so brilliantly designed by +nature to propagate because the wind + + align:start position:0% +nature to propagate because the wind + + + align:start position:0% +nature to propagate because the wind +blows their their seeds all over the + + align:start position:0% +blows their their seeds all over the + + + align:start position:0% +blows their their seeds all over the +place do you all have an image of this + + align:start position:0% +place do you all have an image of this + + + align:start position:0% +place do you all have an image of this +so when they're young the flowers have + + align:start position:0% +so when they're young the flowers have + + + align:start position:0% +so when they're young the flowers have +these golden caps and then when they go + + align:start position:0% +these golden caps and then when they go + + + align:start position:0% +these golden caps and then when they go +to seed they become these rat they have + + align:start position:0% +to seed they become these rat they have + + + align:start position:0% +to seed they become these rat they have +these rounded filaments on the top and + + align:start position:0% +these rounded filaments on the top and + + + align:start position:0% +these rounded filaments on the top and +these rounded filaments in Shakespeare's + + align:start position:0% +these rounded filaments in Shakespeare's + + + align:start position:0% +these rounded filaments in Shakespeare's +day were called golden lads when they + + align:start position:0% +day were called golden lads when they + + + align:start position:0% +day were called golden lads when they +they were actually called these flowers + + align:start position:0% +they were actually called these flowers + + + align:start position:0% +they were actually called these flowers +were called golden lads when they were + + align:start position:0% +were called golden lads when they were + + + align:start position:0% +were called golden lads when they were +in bloom and they were called Chimney + + align:start position:0% +in bloom and they were called Chimney + + + align:start position:0% +in bloom and they were called Chimney +Sweeps + + align:start position:0% +Sweeps + + + align:start position:0% +Sweeps +when they when they went to seed because + + align:start position:0% +when they when they went to seed because + + + align:start position:0% +when they when they went to seed because +they looked exactly like the chimney + + align:start position:0% +they looked exactly like the chimney + + + align:start position:0% +they looked exactly like the chimney +sweepers broom chimney sweepers would + + align:start position:0% +sweepers broom chimney sweepers would + + + align:start position:0% +sweepers broom chimney sweepers would +take these rounded brooms and put them + + align:start position:0% +take these rounded brooms and put them + + + align:start position:0% +take these rounded brooms and put them +up in chimneys to clean them so when + + align:start position:0% +up in chimneys to clean them so when + + + align:start position:0% +up in chimneys to clean them so when +Shakespeare writes in the in the end + + align:start position:0% +Shakespeare writes in the in the end + + + align:start position:0% +Shakespeare writes in the in the end +there he says golden lads and girls all + + align:start position:0% +there he says golden lads and girls all + + + align:start position:0% +there he says golden lads and girls all +must as chimney sweepers come to dust + + align:start position:0% +must as chimney sweepers come to dust + + + align:start position:0% +must as chimney sweepers come to dust +he's describing literally the + + align:start position:0% +he's describing literally the + + + align:start position:0% +he's describing literally the +raises of life in a flower why is that + + align:start position:0% +raises of life in a flower why is that + + + align:start position:0% +raises of life in a flower why is that +wonderful can you see why that's + + align:start position:0% +wonderful can you see why that's + + + align:start position:0% +wonderful can you see why that's +wonderful why that's what art is because + + align:start position:0% +wonderful why that's what art is because + + + align:start position:0% +wonderful why that's what art is because +of course what's happened is that what + + align:start position:0% +of course what's happened is that what + + + align:start position:0% +of course what's happened is that what +shakes we did was turning will create a + + align:start position:0% +shakes we did was turning will create a + + + align:start position:0% +shakes we did was turning will create a +brilliant metaphor out of something + + align:start position:0% +brilliant metaphor out of something + + + align:start position:0% +brilliant metaphor out of something +that's profoundly concrete right and but + + align:start position:0% +that's profoundly concrete right and but + + + align:start position:0% +that's profoundly concrete right and but +but so the phrase golden lad and chimney + + align:start position:0% +but so the phrase golden lad and chimney + + + align:start position:0% +but so the phrase golden lad and chimney +sweeper actually refers to the life + + align:start position:0% +sweeper actually refers to the life + + + align:start position:0% +sweeper actually refers to the life +cycle of a flower we'll think of how + + align:start position:0% +cycle of a flower we'll think of how + + + align:start position:0% +cycle of a flower we'll think of how +much more consoling how profoundly + + align:start position:0% +much more consoling how profoundly + + + align:start position:0% +much more consoling how profoundly +brilliant the lines become when actually + + align:start position:0% +brilliant the lines become when actually + + + align:start position:0% +brilliant the lines become when actually +Shakespeare's metaphor is literally + + align:start position:0% +Shakespeare's metaphor is literally + + + align:start position:0% +Shakespeare's metaphor is literally +linked to the passages of nature to the + + align:start position:0% +linked to the passages of nature to the + + + align:start position:0% +linked to the passages of nature to the +progress of nature right so what I'm + + align:start position:0% +progress of nature right so what I'm + + + align:start position:0% +progress of nature right so what I'm +what I'm calling your attention to is a + + align:start position:0% +what I'm calling your attention to is a + + + align:start position:0% +what I'm calling your attention to is a +brilliant piece of poetry is a piece of + + align:start position:0% +brilliant piece of poetry is a piece of + + + align:start position:0% +brilliant piece of poetry is a piece of +poetry that has a kind of richness and + + align:start position:0% +poetry that has a kind of richness and + + + align:start position:0% +poetry that has a kind of richness and +complexity that's all that that almost + + align:start position:0% +complexity that's all that that almost + + + align:start position:0% +complexity that's all that that almost +couldn't be better + + align:start position:0% +couldn't be better + + + align:start position:0% +couldn't be better +right I mean and even when we don't know + + align:start position:0% +right I mean and even when we don't know + + + align:start position:0% +right I mean and even when we don't know +that about the flower we get the meaning + + align:start position:0% +that about the flower we get the meaning + + + align:start position:0% +that about the flower we get the meaning +of the lines but think how the lines + + align:start position:0% +of the lines but think how the lines + + + align:start position:0% +of the lines but think how the lines +come alive once we recognize that the + + align:start position:0% +come alive once we recognize that the + + + align:start position:0% +come alive once we recognize that the +progress of human life in those couplets + + align:start position:0% +progress of human life in those couplets + + + align:start position:0% +progress of human life in those couplets +is being explicitly associated with with + + align:start position:0% +is being explicitly associated with with + + + align:start position:0% +is being explicitly associated with with +the life cycle of a natural object of a + + align:start position:0% +the life cycle of a natural object of a + + + align:start position:0% +the life cycle of a natural object of a +flower right now this is a great act of + + align:start position:0% +flower right now this is a great act of + + + align:start position:0% +flower right now this is a great act of +poet poetic genius isn't it but where + + align:start position:0% +poet poetic genius isn't it but where + + + align:start position:0% +poet poetic genius isn't it but where +does the genius lie where does it come + + align:start position:0% +does the genius lie where does it come + + + align:start position:0% +does the genius lie where does it come +experience collaborating with the wisdom + + align:start position:0% +experience collaborating with the wisdom + + + align:start position:0% +experience collaborating with the wisdom +of his culture he it takes Shakespeare + + align:start position:0% +of his culture he it takes Shakespeare + + + align:start position:0% +of his culture he it takes Shakespeare +to figure it out I mean I'm not saying + + align:start position:0% +to figure it out I mean I'm not saying + + + align:start position:0% +to figure it out I mean I'm not saying +that it isn't an act of genius for + + align:start position:0% +that it isn't an act of genius for + + + align:start position:0% +that it isn't an act of genius for +Shakespeare to realize the metaphoric + + align:start position:0% +Shakespeare to realize the metaphoric + + + align:start position:0% +Shakespeare to realize the metaphoric +implications of this he did but the + + align:start position:0% +implications of this he did but the + + + align:start position:0% +implications of this he did but the +metaphor is embedded in the way ordinary + + align:start position:0% +metaphor is embedded in the way ordinary + + + align:start position:0% +metaphor is embedded in the way ordinary +people named that flower for hundreds + + align:start position:0% +people named that flower for hundreds + + + align:start position:0% +people named that flower for hundreds +and perhaps thousands of years + + align:start position:0% +and perhaps thousands of years + + + align:start position:0% +and perhaps thousands of years +Shakespeare is collaborating there with + + align:start position:0% +Shakespeare is collaborating there with + + + align:start position:0% +Shakespeare is collaborating there with +the wisdom of his culture with the + + align:start position:0% +the wisdom of his culture with the + + + align:start position:0% +the wisdom of his culture with the +shared understanding of his society in + + align:start position:0% +shared understanding of his society in + + + align:start position:0% +shared understanding of his society in +order to make that brilliant line of + + align:start position:0% +order to make that brilliant line of + + + align:start position:0% +order to make that brilliant line of +poetry so we can take the that idea that + + align:start position:0% +poetry so we can take the that idea that + + + align:start position:0% +poetry so we can take the that idea that +the notion of golden lads as a kind of + + align:start position:0% +the notion of golden lads as a kind of + + + align:start position:0% +the notion of golden lads as a kind of +emblem for the collaborative energies + + align:start position:0% +emblem for the collaborative energies + + + align:start position:0% +emblem for the collaborative energies +that are sometimes released when artists + + align:start position:0% +that are sometimes released when artists + + + align:start position:0% +that are sometimes released when artists +collaborate with the traditions of their + + align:start position:0% +collaborate with the traditions of their + + + align:start position:0% +collaborate with the traditions of their +culture with the traditions of naming + + align:start position:0% +culture with the traditions of naming + + + align:start position:0% +culture with the traditions of naming +with the traditions of understanding + + align:start position:0% +with the traditions of understanding + + + align:start position:0% +with the traditions of understanding +that are embedded and so therefore the + + align:start position:0% +that are embedded and so therefore the + + + align:start position:0% +that are embedded and so therefore the +collaboration is a deep one it's an + + align:start position:0% +collaboration is a deep one it's an + + + align:start position:0% +collaboration is a deep one it's an +intellectual and a menace and a and an + + align:start position:0% +intellectual and a menace and a and an + + + align:start position:0% +intellectual and a menace and a and an +expressive and a creative collaboration + + align:start position:0% +expressive and a creative collaboration + + + align:start position:0% +expressive and a creative collaboration +between the societies understanding of + + align:start position:0% +between the societies understanding of + + + align:start position:0% +between the societies understanding of +the of things of the cultures underst + + align:start position:0% +the of things of the cultures underst + + + align:start position:0% +the of things of the cultures underst +ending of things and the artists + + align:start position:0% +ending of things and the artists + + + align:start position:0% +ending of things and the artists +interaction with those that's an aspect + + align:start position:0% +interaction with those that's an aspect + + + align:start position:0% +interaction with those that's an aspect +of an even deeper aspect of what I mean + + align:start position:0% +of an even deeper aspect of what I mean + + + align:start position:0% +of an even deeper aspect of what I mean +when I say that consensus narrative and + + align:start position:0% +when I say that consensus narrative and + + + align:start position:0% +when I say that consensus narrative and +that movies are a collaborative art form + + align:start position:0% + + + + align:start position:0% + +I've also tried to suggest again and + + align:start position:0% +I've also tried to suggest again and + + + align:start position:0% +I've also tried to suggest again and +again in the course that there are films + + align:start position:0% +again in the course that there are films + + + align:start position:0% +again in the course that there are films +and many of most of the films we've seen + + align:start position:0% +and many of most of the films we've seen + + + align:start position:0% +and many of most of the films we've seen +in this semester also deserve the + + align:start position:0% +in this semester also deserve the + + + align:start position:0% +in this semester also deserve the +designation art and I don't want I've + + align:start position:0% +designation art and I don't want I've + + + align:start position:0% +designation art and I don't want I've +not really wanted to turn the term art + + align:start position:0% +not really wanted to turn the term art + + + align:start position:0% +not really wanted to turn the term art +into a kind of elitist category which + + align:start position:0% +into a kind of elitist category which + + + align:start position:0% +into a kind of elitist category which +sort of in which we from which we must + + align:start position:0% +sort of in which we from which we must + + + align:start position:0% +sort of in which we from which we must +sort of retreat in awe and bow before it + + align:start position:0% +sort of retreat in awe and bow before it + + + align:start position:0% +sort of retreat in awe and bow before it +I want us to think of art in a simpler + + align:start position:0% +I want us to think of art in a simpler + + + align:start position:0% +I want us to think of art in a simpler +and I think more useful way as a form of + + align:start position:0% +and I think more useful way as a form of + + + align:start position:0% +and I think more useful way as a form of +intelligence and competence right in + + align:start position:0% +intelligence and competence right in + + + align:start position:0% +intelligence and competence right in +other words when things are done well in + + align:start position:0% +other words when things are done well in + + + align:start position:0% +other words when things are done well in +a work of art when the thing when when a + + align:start position:0% +a work of art when the thing when when a + + + align:start position:0% +a work of art when the thing when when a +movie is well made when a poem is well + + align:start position:0% +movie is well made when a poem is well + + + align:start position:0% +movie is well made when a poem is well +made we we admire it and we respect it + + align:start position:0% +made we we admire it and we respect it + + + align:start position:0% +made we we admire it and we respect it +and we don't have to get mystical about + + align:start position:0% +and we don't have to get mystical about + + + align:start position:0% +and we don't have to get mystical about +the qualities of art in order to + + align:start position:0% +the qualities of art in order to + + + align:start position:0% +the qualities of art in order to +recognize that intelligence and + + align:start position:0% +recognize that intelligence and + + + align:start position:0% +recognize that intelligence and +competence are are are qualities that + + align:start position:0% +competence are are are qualities that + + + align:start position:0% +competence are are are qualities that +that we value in other aspects of + + align:start position:0% +that we value in other aspects of + + + align:start position:0% +that we value in other aspects of +experience as well as in art itself and + + align:start position:0% +experience as well as in art itself and + + + align:start position:0% +experience as well as in art itself and +what what do I mean specifically by + + align:start position:0% +what what do I mean specifically by + + + align:start position:0% +what what do I mean specifically by +intelligence and competence the most + + align:start position:0% +intelligence and competence the most + + + align:start position:0% +intelligence and competence the most +profound way of understanding this + + align:start position:0% +profound way of understanding this + + + align:start position:0% +profound way of understanding this +argument has to do with what I've spoken + + align:start position:0% +argument has to do with what I've spoken + + + align:start position:0% +argument has to do with what I've spoken +about a number of times in the course + + align:start position:0% +about a number of times in the course + + + align:start position:0% +about a number of times in the course +I've sometimes used the phrase organic + + align:start position:0% +I've sometimes used the phrase organic + + + align:start position:0% +I've sometimes used the phrase organic +form to explain what I meant in that in + + align:start position:0% +form to explain what I meant in that in + + + align:start position:0% +form to explain what I meant in that in +this regard but essentially the idea has + + align:start position:0% +this regard but essentially the idea has + + + align:start position:0% +this regard but essentially the idea has +to do with the sense with the + + align:start position:0% +to do with the sense with the + + + align:start position:0% +to do with the sense with the +recognition that a serious artist will + + align:start position:0% +recognition that a serious artist will + + + align:start position:0% +recognition that a serious artist will +use instruments that further his or her + + align:start position:0% +use instruments that further his or her + + + align:start position:0% +use instruments that further his or her +intentions effectively and fully that is + + align:start position:0% +intentions effectively and fully that is + + + align:start position:0% +intentions effectively and fully that is +to say that there's a connection between + + align:start position:0% +to say that there's a connection between + + + align:start position:0% +to say that there's a connection between +the formal or stylistic choices that an + + align:start position:0% +the formal or stylistic choices that an + + + align:start position:0% +the formal or stylistic choices that an +artist makes and the content that is + + align:start position:0% +artist makes and the content that is + + + align:start position:0% +artist makes and the content that is +part of the artwork that is to say that + + align:start position:0% +part of the artwork that is to say that + + + align:start position:0% +part of the artwork that is to say that +there's a that there's a link or a bora + + align:start position:0% +there's a that there's a link or a bora + + + align:start position:0% +there's a that there's a link or a bora +ora ora or a connection between the + + align:start position:0% +ora ora or a connection between the + + + align:start position:0% +ora ora or a connection between the +formal choices that a writer or a + + align:start position:0% +formal choices that a writer or a + + + align:start position:0% +formal choices that a writer or a +filmmaker makes and the content intended + + align:start position:0% +filmmaker makes and the content intended + + + align:start position:0% +filmmaker makes and the content intended +to be to be communicated from and we can + + align:start position:0% +to be to be communicated from and we can + + + align:start position:0% +to be to be communicated from and we can +we can think of the term competence + + align:start position:0% +we can think of the term competence + + + align:start position:0% +we can think of the term competence +having to do simply with wit with with + + align:start position:0% +having to do simply with wit with with + + + align:start position:0% +having to do simply with wit with with +the idea of technical mastery in other + + align:start position:0% +the idea of technical mastery in other + + + align:start position:0% +the idea of technical mastery in other +words a competent poet is a master of + + align:start position:0% +words a competent poet is a master of + + + align:start position:0% +words a competent poet is a master of +language is a master of metaphor is a + + align:start position:0% +language is a master of metaphor is a + + + align:start position:0% +language is a master of metaphor is a +master of grammar you can't be a great + + align:start position:0% +master of grammar you can't be a great + + + align:start position:0% +master of grammar you can't be a great +poet if you have no understanding of + + align:start position:0% +poet if you have no understanding of + + + align:start position:0% +poet if you have no understanding of +grammar or whatever because you'd be + + align:start position:0% +grammar or whatever because you'd be + + + align:start position:0% +grammar or whatever because you'd be +you'd be throwing away one of the great + + align:start position:0% +you'd be throwing away one of the great + + + align:start position:0% +you'd be throwing away one of the great +technical resources of the language + + align:start position:0% +technical resources of the language + + + align:start position:0% +technical resources of the language +which is which is the group the + + align:start position:0% +which is which is the group the + + + align:start position:0% +which is which is the group the +complexity that grows out of a mastery + + align:start position:0% +complexity that grows out of a mastery + + + align:start position:0% +complexity that grows out of a mastery +of grammar by the same token you + + align:start position:0% +of grammar by the same token you + + + align:start position:0% +of grammar by the same token you +couldn't have a serious filmmaker who + + align:start position:0% +couldn't have a serious filmmaker who + + + align:start position:0% +couldn't have a serious filmmaker who +didn't have a deep profound sense of + + align:start position:0% +didn't have a deep profound sense of + + + align:start position:0% +didn't have a deep profound sense of +what it meant to create a visual story + + align:start position:0% +what it meant to create a visual story + + + align:start position:0% +what it meant to create a visual story +what it meant to try to embody meaning + + align:start position:0% +what it meant to try to embody meaning + + + align:start position:0% +what it meant to try to embody meaning +in in audio-visual ways right you + + align:start position:0% +in in audio-visual ways right you + + + align:start position:0% +in in audio-visual ways right you +couldn't have a great filmmaker who was + + align:start position:0% +couldn't have a great filmmaker who was + + + align:start position:0% +couldn't have a great filmmaker who was +oblivious entirely to the visual nature + + align:start position:0% +oblivious entirely to the visual nature + + + align:start position:0% +oblivious entirely to the visual nature +of his experience he'd have to eat yeah + + align:start position:0% +of his experience he'd have to eat yeah + + + align:start position:0% +of his experience he'd have to eat yeah +the the filmmaker would the filmmaker + + align:start position:0% +the the filmmaker would the filmmaker + + + align:start position:0% +the the filmmaker would the filmmaker +what any serious filmmaker has to be + + align:start position:0% +what any serious filmmaker has to be + + + align:start position:0% +what any serious filmmaker has to be +always aware of the special qualities + + align:start position:0% +always aware of the special qualities + + + align:start position:0% +always aware of the special qualities +and properties of the medium in which he + + align:start position:0% +and properties of the medium in which he + + + align:start position:0% +and properties of the medium in which he +or she is working so if we think of art + + align:start position:0% +or she is working so if we think of art + + + align:start position:0% +or she is working so if we think of art +then not as not as a mystical category + + align:start position:0% +then not as not as a mystical category + + + align:start position:0% +then not as not as a mystical category +but as as as an expression of + + align:start position:0% +but as as as an expression of + + + align:start position:0% +but as as as an expression of +intelligence and mastery intelligence + + align:start position:0% +intelligence and mastery intelligence + + + align:start position:0% +intelligence and mastery intelligence +and competence perhaps we've demystified + + align:start position:0% +and competence perhaps we've demystified + + + align:start position:0% +and competence perhaps we've demystified +it a bit and given us grounds for + + align:start position:0% +it a bit and given us grounds for + + + align:start position:0% +it a bit and given us grounds for +actually making judgments about + + align:start position:0% +actually making judgments about + + + align:start position:0% +actually making judgments about +particular films and particular passages + + align:start position:0% +particular films and particular passages + + + align:start position:0% +particular films and particular passages +and moments in film and let me remind + + align:start position:0% +and moments in film and let me remind + + + align:start position:0% +and moments in film and let me remind +you again that a second version of this + + align:start position:0% +you again that a second version of this + + + align:start position:0% +you again that a second version of this +argument about the relationship of at + + align:start position:0% +argument about the relationship of at + + + align:start position:0% +argument about the relationship of at +least in part about the relationship + + align:start position:0% +least in part about the relationship + + + align:start position:0% +least in part about the relationship +between art and its and what what I had + + align:start position:0% +between art and its and what what I had + + + align:start position:0% +between art and its and what what I had +sometimes called entertainment the + + align:start position:0% +sometimes called entertainment the + + + align:start position:0% +sometimes called entertainment the +greater complexity or richness of art + + align:start position:0% +greater complexity or richness of art + + + align:start position:0% +greater complexity or richness of art +can be embodied also not only in this + + align:start position:0% +can be embodied also not only in this + + + align:start position:0% +can be embodied also not only in this +first principle of a connection between + + align:start position:0% +first principle of a connection between + + + align:start position:0% +first principle of a connection between +the stylistic and formal choices and the + + align:start position:0% +the stylistic and formal choices and the + + + align:start position:0% +the stylistic and formal choices and the +content but in this second way in the + + align:start position:0% +content but in this second way in the + + + align:start position:0% +content but in this second way in the +second category or second perspective as + + align:start position:0% +second category or second perspective as + + + align:start position:0% +second category or second perspective as +well in terms of what I've called + + align:start position:0% +well in terms of what I've called + + + align:start position:0% +well in terms of what I've called +texture or multiplicity right the + + align:start position:0% +texture or multiplicity right the + + + align:start position:0% +texture or multiplicity right the +multiplicity principles let me just + + align:start position:0% +multiplicity principles let me just + + + align:start position:0% +multiplicity principles let me just +quickly remind you of a couple of + + align:start position:0% +quickly remind you of a couple of + + + align:start position:0% +quickly remind you of a couple of +examples we've looked at in the course + + align:start position:0% +examples we've looked at in the course + + + align:start position:0% +examples we've looked at in the course +just as a way of giving you some + + align:start position:0% +just as a way of giving you some + + + align:start position:0% +just as a way of giving you some +instances from which you can look from + + align:start position:0% +instances from which you can look from + + + align:start position:0% +instances from which you can look from +which you can extrapolate your your own + + align:start position:0% +which you can extrapolate your your own + + + align:start position:0% +which you can extrapolate your your own +responses to other texts + + align:start position:0% +responses to other texts + + + align:start position:0% +responses to other texts +do you remember for example the scene of + + align:start position:0% +do you remember for example the scene of + + + align:start position:0% +do you remember for example the scene of +that that we that we looked at fairly + + align:start position:0% +that that we that we looked at fairly + + + align:start position:0% +that that we that we looked at fairly +closely in McCabe and mrs. Miller that + + align:start position:0% +closely in McCabe and mrs. Miller that + + + align:start position:0% +closely in McCabe and mrs. Miller that +disturbing ironic shootout on the bridge + + align:start position:0% +disturbing ironic shootout on the bridge + + + align:start position:0% +disturbing ironic shootout on the bridge +in which a murderous young killer goods + + align:start position:0% +in which a murderous young killer goods + + + align:start position:0% +in which a murderous young killer goods +a young farmer into taking the gun out + + align:start position:0% +a young farmer into taking the gun out + + + align:start position:0% +a young farmer into taking the gun out +of his holster and shoots him down in + + align:start position:0% +of his holster and shoots him down in + + + align:start position:0% +of his holster and shoots him down in +cold blood would simply remind you about + + align:start position:0% +cold blood would simply remind you about + + + align:start position:0% +cold blood would simply remind you about +the way in which what Gaytan part of + + align:start position:0% +the way in which what Gaytan part of + + + align:start position:0% +the way in which what Gaytan part of +what gave that scene its power + + align:start position:0% +what gave that scene its power + + + align:start position:0% +what gave that scene its power +had to do with the fact that there was a + + align:start position:0% +had to do with the fact that there was a + + + align:start position:0% +had to do with the fact that there was a +psychological dimension to it + + align:start position:0% +psychological dimension to it + + + align:start position:0% +psychological dimension to it +the young murderer was committing the + + align:start position:0% +the young murderer was committing the + + + align:start position:0% +the young murderer was committing the +murder had been frustrated because he + + align:start position:0% +murder had been frustrated because he + + + align:start position:0% +murder had been frustrated because he +tried to show off earlier and not + + align:start position:0% +tried to show off earlier and not + + + align:start position:0% +tried to show off earlier and not +succeeded and that imparted a terrible + + align:start position:0% +succeeded and that imparted a terrible + + + align:start position:0% +succeeded and that imparted a terrible +horrible irony to the scene because you + + align:start position:0% +horrible irony to the scene because you + + + align:start position:0% +horrible irony to the scene because you +realize that this boy this murder is + + align:start position:0% +realize that this boy this murder is + + + align:start position:0% +realize that this boy this murder is +completely fortuitous it's completely + + align:start position:0% +completely fortuitous it's completely + + + align:start position:0% +completely fortuitous it's completely +accidental if that if that little + + align:start position:0% +accidental if that if that little + + + align:start position:0% +accidental if that if that little +murderer had succeeded earlier in + + align:start position:0% +murderer had succeeded earlier in + + + align:start position:0% +murderer had succeeded earlier in +shooting the bottle that was floating + + align:start position:0% +shooting the bottle that was floating + + + align:start position:0% +shooting the bottle that was floating +around on the on the frozen on the + + align:start position:0% +around on the on the frozen on the + + + align:start position:0% +around on the on the frozen on the +frozen pond he probably would not have + + align:start position:0% +frozen pond he probably would not have + + + align:start position:0% +frozen pond he probably would not have +child he definitely would not have + + align:start position:0% +child he definitely would not have + + + align:start position:0% +child he definitely would not have +challenged this young farmer to try to + + align:start position:0% +challenged this young farmer to try to + + + align:start position:0% +challenged this young farmer to try to +get back his mojo and show the people + + align:start position:0% +get back his mojo and show the people + + + align:start position:0% +get back his mojo and show the people +around him that he knew how to handle a + + align:start position:0% +around him that he knew how to handle a + + + align:start position:0% +around him that he knew how to handle a +gun so it made this is and and of course + + align:start position:0% +gun so it made this is and and of course + + + align:start position:0% +gun so it made this is and and of course +that and then so that that already + + align:start position:0% +that and then so that that already + + + align:start position:0% +that and then so that that already +created a kind of complexity and texture + + align:start position:0% +created a kind of complexity and texture + + + align:start position:0% +created a kind of complexity and texture +but then when we add in the fact that + + align:start position:0% +but then when we add in the fact that + + + align:start position:0% +but then when we add in the fact that +this scene itself is one of the central + + align:start position:0% +this scene itself is one of the central + + + align:start position:0% +this scene itself is one of the central +iconic scenes in all westerns two males + + align:start position:0% +iconic scenes in all westerns two males + + + align:start position:0% +iconic scenes in all westerns two males +stand with facing off against each other + + align:start position:0% +stand with facing off against each other + + + align:start position:0% +stand with facing off against each other +ready to shoot we come to realize that + + align:start position:0% +ready to shoot we come to realize that + + + align:start position:0% +ready to shoot we come to realize that +the I various anti-heroic and and ironic + + align:start position:0% +the I various anti-heroic and and ironic + + + align:start position:0% +the I various anti-heroic and and ironic +ways in which this shootout is handled + + align:start position:0% +ways in which this shootout is handled + + + align:start position:0% +ways in which this shootout is handled +throws a profoundly critical and + + align:start position:0% +throws a profoundly critical and + + + align:start position:0% +throws a profoundly critical and +disturbing light on dozens and perhaps + + align:start position:0% +disturbing light on dozens and perhaps + + + align:start position:0% +disturbing light on dozens and perhaps +hundreds of earlier such scenes that + + align:start position:0% +hundreds of earlier such scenes that + + + align:start position:0% +hundreds of earlier such scenes that +have occurred in westerns that the very + + align:start position:0% +have occurred in westerns that the very + + + align:start position:0% +have occurred in westerns that the very +basis of the westerns embrace of + + align:start position:0% +basis of the westerns embrace of + + + align:start position:0% +basis of the westerns embrace of +violence its notion that you can achieve + + align:start position:0% +violence its notion that you can achieve + + + align:start position:0% +violence its notion that you can achieve +regeneration through violence is put in + + align:start position:0% +regeneration through violence is put in + + + align:start position:0% +regeneration through violence is put in +question by that scene so there's a + + align:start position:0% +question by that scene so there's a + + + align:start position:0% +question by that scene so there's a +texture or multiplicity in the scene + + align:start position:0% +texture or multiplicity in the scene + + + align:start position:0% +texture or multiplicity in the scene +it's not if forwards the story it shows + + align:start position:0% +it's not if forwards the story it shows + + + align:start position:0% +it's not if forwards the story it shows +it shows a violent act it tells us + + align:start position:0% +it shows a violent act it tells us + + + align:start position:0% +it shows a violent act it tells us +something about the psychology of the + + align:start position:0% +something about the psychology of the + + + align:start position:0% +something about the psychology of the +murderer but even more than that it + + align:start position:0% +murderer but even more than that it + + + align:start position:0% +murderer but even more than that it +resonates through the whole history of + + align:start position:0% +resonates through the whole history of + + + align:start position:0% +resonates through the whole history of +the Western because the shootout itself + + align:start position:0% +the Western because the shootout itself + + + align:start position:0% +the Western because the shootout itself +has been shown in such an anti heroic + + align:start position:0% +has been shown in such an anti heroic + + + align:start position:0% +has been shown in such an anti heroic +such an ironic light texture + + align:start position:0% +such an ironic light texture + + + align:start position:0% +such an ironic light texture +multiplicity remember the moment in + + align:start position:0% +multiplicity remember the moment in + + + align:start position:0% +multiplicity remember the moment in +cabaret where the Joel gray character + + align:start position:0% +cabaret where the Joel gray character + + + align:start position:0% +cabaret where the Joel gray character +the the interlocutor the the at one + + align:start position:0% +the the interlocutor the the at one + + + align:start position:0% +the the interlocutor the the at one +point kneels down while he's talking and + + align:start position:0% +point kneels down while he's talking and + + + align:start position:0% +point kneels down while he's talking and +during the mud wrestling scene and picks + + align:start position:0% +during the mud wrestling scene and picks + + + align:start position:0% +during the mud wrestling scene and picks +up a piece of mud on his finger rubs it + + align:start position:0% +up a piece of mud on his finger rubs it + + + align:start position:0% +up a piece of mud on his finger rubs it +on his face like this and gives a Hitler + + align:start position:0% +on his face like this and gives a Hitler + + + align:start position:0% +on his face like this and gives a Hitler +gives himself a Hitler mustache I mean + + align:start position:0% +gives himself a Hitler mustache I mean + + + align:start position:0% +gives himself a Hitler mustache I mean +it's a rich comic moment but isn't it + + align:start position:0% +it's a rich comic moment but isn't it + + + align:start position:0% +it's a rich comic moment but isn't it +more than that especially in the context + + align:start position:0% +more than that especially in the context + + + align:start position:0% +more than that especially in the context +of as the film proceeds we understand + + align:start position:0% +of as the film proceeds we understand + + + align:start position:0% +of as the film proceeds we understand +from that moment that the Nazis are + + align:start position:0% +from that moment that the Nazis are + + + align:start position:0% +from that moment that the Nazis are +objects of fun and mockery not that + + align:start position:0% +objects of fun and mockery not that + + + align:start position:0% +objects of fun and mockery not that +dangerous it would seem at least that + + align:start position:0% +dangerous it would seem at least that + + + align:start position:0% +dangerous it would seem at least that +the Cabaret feels superior to it and of + + align:start position:0% +the Cabaret feels superior to it and of + + + align:start position:0% +the Cabaret feels superior to it and of +course when we think about the course of + + align:start position:0% +course when we think about the course of + + + align:start position:0% +course when we think about the course of +the film when we think about how the + + align:start position:0% +the film when we think about how the + + + align:start position:0% +the film when we think about how the +Nazis moved from the periphery to the + + align:start position:0% +Nazis moved from the periphery to the + + + align:start position:0% +Nazis moved from the periphery to the +center of the movie we come to recognize + + align:start position:0% +center of the movie we come to recognize + + + align:start position:0% +center of the movie we come to recognize +that that moment especially in + + align:start position:0% +that that moment especially in + + + align:start position:0% +that that moment especially in +retrospect that moment has a particular + + align:start position:0% +retrospect that moment has a particular + + + align:start position:0% +retrospect that moment has a particular +kind of ironic richness that's partly a + + align:start position:0% +kind of ironic richness that's partly a + + + align:start position:0% +kind of ironic richness that's partly a +function of the obliviousness that + + align:start position:0% +function of the obliviousness that + + + align:start position:0% +function of the obliviousness that +everyone in the Cabaret and even the + + align:start position:0% +everyone in the Cabaret and even the + + + align:start position:0% +everyone in the Cabaret and even the +Joel Grey characters despite his + + align:start position:0% +Joel Grey characters despite his + + + align:start position:0% +Joel Grey characters despite his +apparent cynicism and worldliness seems + + align:start position:0% +apparent cynicism and worldliness seems + + + align:start position:0% +apparent cynicism and worldliness seems +to have about they were all they're + + align:start position:0% +to have about they were all they're + + + align:start position:0% +to have about they were all they're +innocent they're naive about the power + + align:start position:0% +innocent they're naive about the power + + + align:start position:0% +innocent they're naive about the power +and danger of the rise of the Nazis and + + align:start position:0% +and danger of the rise of the Nazis and + + + align:start position:0% +and danger of the rise of the Nazis and +let me give you one last example + + align:start position:0% +let me give you one last example + + + align:start position:0% +let me give you one last example +although there are many others that we + + align:start position:0% +although there are many others that we + + + align:start position:0% +although there are many others that we +mentioned do you remember the moment in + + align:start position:0% +mentioned do you remember the moment in + + + align:start position:0% +mentioned do you remember the moment in +the passage I showed you from from the + + align:start position:0% +the passage I showed you from from the + + + align:start position:0% +the passage I showed you from from the +De Sica movie Umberto D that very brief + + align:start position:0% +De Sica movie Umberto D that very brief + + + align:start position:0% +De Sica movie Umberto D that very brief +moment where we see a man get on a get + + align:start position:0% +moment where we see a man get on a get + + + align:start position:0% +moment where we see a man get on a get +on a tram a bus and sit next to someone + + align:start position:0% +on a tram a bus and sit next to someone + + + align:start position:0% +on a tram a bus and sit next to someone +on the bus and the bus moves there it's + + align:start position:0% +on the bus and the bus moves there it's + + + align:start position:0% +on the bus and the bus moves there it's +a completely wordless sequence and + + align:start position:0% +a completely wordless sequence and + + + align:start position:0% +a completely wordless sequence and +there's a character we've never seen in + + align:start position:0% +there's a character we've never seen in + + + align:start position:0% +there's a character we've never seen in +the film before who sits down next to + + align:start position:0% +the film before who sits down next to + + + align:start position:0% +the film before who sits down next to +the protagonist no words exchanged when + + align:start position:0% +the protagonist no words exchanged when + + + align:start position:0% +the protagonist no words exchanged when +our protagonist gets up and gets off the + + align:start position:0% +our protagonist gets up and gets off the + + + align:start position:0% +our protagonist gets up and gets off the +bus the camera lingers briefly on the + + align:start position:0% +bus the camera lingers briefly on the + + + align:start position:0% +bus the camera lingers briefly on the +man he'd left behind and we see that man + + align:start position:0% +man he'd left behind and we see that man + + + align:start position:0% +man he'd left behind and we see that man +go like this and what I suggested to you + + align:start position:0% +go like this and what I suggested to you + + + align:start position:0% +go like this and what I suggested to you +was again I suggested that this was a + + align:start position:0% +was again I suggested that this was a + + + align:start position:0% +was again I suggested that this was a +moment of richness and and and + + align:start position:0% +moment of richness and and and + + + align:start position:0% +moment of richness and and and +complexity of multiplicity in a way + + align:start position:0% +complexity of multiplicity in a way + + + align:start position:0% +complexity of multiplicity in a way +because one implication of that scene + + align:start position:0% +because one implication of that scene + + + align:start position:0% +because one implication of that scene +was that the man this stranger that + + align:start position:0% +was that the man this stranger that + + + align:start position:0% +was that the man this stranger that +we'll never meet again that we only saw + + align:start position:0% +we'll never meet again that we only saw + + + align:start position:0% +we'll never meet again that we only saw +for one brief instant in the course of + + align:start position:0% +for one brief instant in the course of + + + align:start position:0% +for one brief instant in the course of +the film might have concealed a story as + + align:start position:0% +the film might have concealed a story as + + + align:start position:0% +the film might have concealed a story as +deep as rich and as moving as that of + + align:start position:0% +deep as rich and as moving as that of + + + align:start position:0% +deep as rich and as moving as that of +our hero Umberto D who was now leaving + + align:start position:0% +our hero Umberto D who was now leaving + + + align:start position:0% +our hero Umberto D who was now leaving +the tram and will shortly we will + + align:start position:0% +the tram and will shortly we will + + + align:start position:0% +the tram and will shortly we will +shortly be following him so again a + + align:start position:0% +shortly be following him so again a + + + align:start position:0% +shortly be following him so again a +moment of + + align:start position:0% +moment of + + + align:start position:0% +moment of +laxity or richness that that embodies + + align:start position:0% +laxity or richness that that embodies + + + align:start position:0% +laxity or richness that that embodies +central meanings in the helps us to see + + align:start position:0% +central meanings in the helps us to see + + + align:start position:0% +central meanings in the helps us to see +central meanings in the in the text well + + align:start position:0% +central meanings in the in the text well + + + align:start position:0% +central meanings in the in the text well +I have a final example of this kind of + + align:start position:0% +I have a final example of this kind of + + + align:start position:0% +I have a final example of this kind of +texture or multiplicity it's an example + + align:start position:0% +texture or multiplicity it's an example + + + align:start position:0% +texture or multiplicity it's an example +I had hoped to show you when we talked + + align:start position:0% +I had hoped to show you when we talked + + + align:start position:0% +I had hoped to show you when we talked +about Kurosawa last week but I didn't + + align:start position:0% +about Kurosawa last week but I didn't + + + align:start position:0% +about Kurosawa last week but I didn't +quite make enough time in my in my + + align:start position:0% +quite make enough time in my in my + + + align:start position:0% +quite make enough time in my in my +lecture and I want to show it here as a + + align:start position:0% +lecture and I want to show it here as a + + + align:start position:0% +lecture and I want to show it here as a +kind of final homage to that great + + align:start position:0% +kind of final homage to that great + + + align:start position:0% +kind of final homage to that great +director and as a way of reminding you + + align:start position:0% +director and as a way of reminding you + + + align:start position:0% +director and as a way of reminding you +of the variety of performances that the + + align:start position:0% +of the variety of performances that the + + + align:start position:0% +of the variety of performances that the +great actor Toshiro Mifune who plays the + + align:start position:0% +great actor Toshiro Mifune who plays the + + + align:start position:0% +great actor Toshiro Mifune who plays the +rapist in Rashomon was capable of so + + align:start position:0% +rapist in Rashomon was capable of so + + + align:start position:0% +rapist in Rashomon was capable of so +here is a scene a very minor scene + + align:start position:0% +here is a scene a very minor scene + + + align:start position:0% +here is a scene a very minor scene +actually from the film from the great + + align:start position:0% +actually from the film from the great + + + align:start position:0% +actually from the film from the great +Kurosawa film Seven Samurai which I + + align:start position:0% +Kurosawa film Seven Samurai which I + + + align:start position:0% +Kurosawa film Seven Samurai which I +mentioned last time let me set the + + align:start position:0% +mentioned last time let me set the + + + align:start position:0% +mentioned last time let me set the +context for you before I show it to you + + align:start position:0% +context for you before I show it to you + + + align:start position:0% +context for you before I show it to you +it's a very brief scene Seven Samurai + + align:start position:0% +it's a very brief scene Seven Samurai + + + align:start position:0% +it's a very brief scene Seven Samurai +which I've sometimes shown in this + + align:start position:0% +which I've sometimes shown in this + + + align:start position:0% +which I've sometimes shown in this +course I actually toyed with the idea of + + align:start position:0% +course I actually toyed with the idea of + + + align:start position:0% +course I actually toyed with the idea of +having you watch both but they're both + + align:start position:0% +having you watch both but they're both + + + align:start position:0% +having you watch both but they're both +Rashomon and seven samurai but Seven + + align:start position:0% +Rashomon and seven samurai but Seven + + + align:start position:0% +Rashomon and seven samurai but Seven +Samurai is a very long movie and I + + align:start position:0% +Samurai is a very long movie and I + + + align:start position:0% +Samurai is a very long movie and I +sometimes warn students about it when I + + align:start position:0% +sometimes warn students about it when I + + + align:start position:0% +sometimes warn students about it when I +show it in the class I decided not to do + + align:start position:0% +show it in the class I decided not to do + + + align:start position:0% +show it in the class I decided not to do +it but I hope all of you over the + + align:start position:0% +it but I hope all of you over the + + + align:start position:0% +it but I hope all of you over the +Christmas break soon we'll look at Seven + + align:start position:0% +Christmas break soon we'll look at Seven + + + align:start position:0% +Christmas break soon we'll look at Seven +Samurai it will resonate especially for + + align:start position:0% +Samurai it will resonate especially for + + + align:start position:0% +Samurai it will resonate especially for +you it since you've just seen an earlier + + align:start position:0% +you it since you've just seen an earlier + + + align:start position:0% +you it since you've just seen an earlier +Kurosawa film + + align:start position:0% +Kurosawa film + + + align:start position:0% +Kurosawa film +well this immensely long film has a + + align:start position:0% +well this immensely long film has a + + + align:start position:0% +well this immensely long film has a +wonderful epic amplitude and the long + + align:start position:0% +wonderful epic amplitude and the long + + + align:start position:0% +wonderful epic amplitude and the long +first section of the film involves + + align:start position:0% +first section of the film involves + + + align:start position:0% +first section of the film involves +essentially the assembling of a group of + + align:start position:0% +essentially the assembling of a group of + + + align:start position:0% +essentially the assembling of a group of +samurai who are going to go to a village + + align:start position:0% +samurai who are going to go to a village + + + align:start position:0% +samurai who are going to go to a village +to defend this village of farmers from + + align:start position:0% +to defend this village of farmers from + + + align:start position:0% +to defend this village of farmers from +the depredations of bandits when the + + align:start position:0% +the depredations of bandits when the + + + align:start position:0% +the depredations of bandits when the +film opens some farmers are make their + + align:start position:0% +film opens some farmers are make their + + + align:start position:0% +film opens some farmers are make their +way to a great city trying to find + + align:start position:0% +way to a great city trying to find + + + align:start position:0% +way to a great city trying to find +samurai who will come and defend them + + align:start position:0% +samurai who will come and defend them + + + align:start position:0% +samurai who will come and defend them +and they're the and this the first + + align:start position:0% +and they're the and this the first + + + align:start position:0% +and they're the and this the first +section of the film shows that the this + + align:start position:0% +section of the film shows that the this + + + align:start position:0% +section of the film shows that the this +group of samurai slowly coming together + + align:start position:0% +group of samurai slowly coming together + + + align:start position:0% +group of samurai slowly coming together +but only six of them are in the group + + align:start position:0% +but only six of them are in the group + + + align:start position:0% +but only six of them are in the group +because there was a seventh who tried to + + align:start position:0% +because there was a seventh who tried to + + + align:start position:0% +because there was a seventh who tried to +join them the Toshiro Mifune character + + align:start position:0% +join them the Toshiro Mifune character + + + align:start position:0% +join them the Toshiro Mifune character +but he was rejected in + + align:start position:0% +but he was rejected in + + + align:start position:0% +but he was rejected in +earlier part of the film that we haven't + + align:start position:0% +earlier part of the film that we haven't + + + align:start position:0% +earlier part of the film that we haven't +yet seen that would that you that that + + align:start position:0% +yet seen that would that you that that + + + align:start position:0% +yet seen that would that you that that +we have seen but when you look at the + + align:start position:0% +we have seen but when you look at the + + + align:start position:0% +we have seen but when you look at the +clip you will not have seen yet because + + align:start position:0% +clip you will not have seen yet because + + + align:start position:0% +clip you will not have seen yet because +he's not really a samurai he's he's a + + align:start position:0% +he's not really a samurai he's he's a + + + align:start position:0% +he's not really a samurai he's he's a +he's a commoner who was trying to think + + align:start position:0% +he's a commoner who was trying to think + + + align:start position:0% +he's a commoner who was trying to think +that he was a samurai he grew up top not + + align:start position:0% +that he was a samurai he grew up top not + + + align:start position:0% +that he was a samurai he grew up top not +he can handle the sword but they could + + align:start position:0% +he can handle the sword but they could + + + align:start position:0% +he can handle the sword but they could +tell in various ways he didn't know the + + align:start position:0% +tell in various ways he didn't know the + + + align:start position:0% +tell in various ways he didn't know the +poetry that samurai knew a lot of ways + + align:start position:0% +poetry that samurai knew a lot of ways + + + align:start position:0% +poetry that samurai knew a lot of ways +in which they figured out that the + + align:start position:0% +in which they figured out that the + + + align:start position:0% +in which they figured out that the +Mifune character really was not a + + align:start position:0% +Mifune character really was not a + + + align:start position:0% +Mifune character really was not a +samurai so they didn't let him join them + + align:start position:0% +samurai so they didn't let him join them + + + align:start position:0% +samurai so they didn't let him join them +and in this theme we're going to say + + align:start position:0% +and in this theme we're going to say + + + align:start position:0% +and in this theme we're going to say +it's two or two and a half minutes long + + align:start position:0% +it's two or two and a half minutes long + + + align:start position:0% +it's two or two and a half minutes long +and this is one reason I wanted you to + + align:start position:0% +and this is one reason I wanted you to + + + align:start position:0% +and this is one reason I wanted you to +look at it because it's it's so brief + + align:start position:0% +look at it because it's it's so brief + + + align:start position:0% +look at it because it's it's so brief +and its basic function is so simple the + + align:start position:0% +and its basic function is so simple the + + + align:start position:0% +and its basic function is so simple the +point of the scene is to get the samurai + + align:start position:0% +point of the scene is to get the samurai + + + align:start position:0% +point of the scene is to get the samurai +to the village where the central aspect + + align:start position:0% +to the village where the central aspect + + + align:start position:0% +to the village where the central aspect +with a where the central adventure of + + align:start position:0% +with a where the central adventure of + + + align:start position:0% +with a where the central adventure of +the film will take place right so we can + + align:start position:0% +the film will take place right so we can + + + align:start position:0% +the film will take place right so we can +almost think of part one as a kind of + + align:start position:0% +almost think of part one as a kind of + + + align:start position:0% +almost think of part one as a kind of +prologue or or at least an introductory + + align:start position:0% +prologue or or at least an introductory + + + align:start position:0% +prologue or or at least an introductory +preparation the film really isn't going + + align:start position:0% +preparation the film really isn't going + + + align:start position:0% +preparation the film really isn't going +to get going in it in one sense until + + align:start position:0% +to get going in it in one sense until + + + align:start position:0% +to get going in it in one sense until +after this transition moment there so + + align:start position:0% +after this transition moment there so + + + align:start position:0% +after this transition moment there so +the sequence we're looking at it as a + + align:start position:0% +the sequence we're looking at it as a + + + align:start position:0% +the sequence we're looking at it as a +very simple narrative function it's to + + align:start position:0% +very simple narrative function it's to + + + align:start position:0% +very simple narrative function it's to +get the samurai from the city to the + + align:start position:0% +get the samurai from the city to the + + + align:start position:0% +get the samurai from the city to the +rural village and we see them making + + align:start position:0% +rural village and we see them making + + + align:start position:0% +rural village and we see them making +this trip but as you'll see the scene + + align:start position:0% +this trip but as you'll see the scene + + + align:start position:0% +this trip but as you'll see the scene +has a much greater multiplicity a much a + + align:start position:0% +has a much greater multiplicity a much a + + + align:start position:0% +has a much greater multiplicity a much a +much greater significance than simply + + align:start position:0% +much greater significance than simply + + + align:start position:0% +much greater significance than simply +this simple narrative significance of + + align:start position:0% +this simple narrative significance of + + + align:start position:0% +this simple narrative significance of +moving the actors to a new location here + + align:start position:0% +moving the actors to a new location here + + + align:start position:0% +moving the actors to a new location here +we go and see he's following them in the + + align:start position:0% +we go and see he's following them in the + + + align:start position:0% +we go and see he's following them in the +back there and they say go away + + align:start position:0% + + + + align:start position:0% + +all right so I've seen a scene of + + align:start position:0% +all right so I've seen a scene of + + + align:start position:0% +all right so I've seen a scene of +unexpected comedy right but what else + + align:start position:0% +unexpected comedy right but what else + + + align:start position:0% +unexpected comedy right but what else +can you see how much is going on there + + align:start position:0% +can you see how much is going on there + + + align:start position:0% +can you see how much is going on there +if we if we think about the scene for a + + align:start position:0% +if we if we think about the scene for a + + + align:start position:0% +if we if we think about the scene for a +moment we can see okay the first + + align:start position:0% +moment we can see okay the first + + + align:start position:0% +moment we can see okay the first +function of the scene is to get them to + + align:start position:0% +function of the scene is to get them to + + + align:start position:0% +function of the scene is to get them to +the village right but it's a wonderful + + align:start position:0% +the village right but it's a wonderful + + + align:start position:0% +the village right but it's a wonderful +example of the multiplicity principle it + + align:start position:0% +example of the multiplicity principle it + + + align:start position:0% +example of the multiplicity principle it +seems to me okay it forwards the story + + align:start position:0% +seems to me okay it forwards the story + + + align:start position:0% +seems to me okay it forwards the story +and in some simple sense but what does + + align:start position:0% +and in some simple sense but what does + + + align:start position:0% +and in some simple sense but what does +it also do it defines the samurai in + + align:start position:0% +it also do it defines the samurai in + + + align:start position:0% +it also do it defines the samurai in +some basic way first of all there's the + + align:start position:0% +some basic way first of all there's the + + + align:start position:0% +some basic way first of all there's the +legitimate samurai have a sense of humor + + align:start position:0% +legitimate samurai have a sense of humor + + + align:start position:0% +legitimate samurai have a sense of humor +and the they but even more than that + + align:start position:0% +and the they but even more than that + + + align:start position:0% +and the they but even more than that +when we went as we're watching this + + align:start position:0% +when we went as we're watching this + + + align:start position:0% +when we went as we're watching this +scene what do we see among other things + + align:start position:0% +scene what do we see among other things + + + align:start position:0% +scene what do we see among other things +a wonderful very brief dramatization of + + align:start position:0% +a wonderful very brief dramatization of + + + align:start position:0% +a wonderful very brief dramatization of +the conflict between man and nature + + align:start position:0% +the conflict between man and nature + + + align:start position:0% +the conflict between man and nature +think of how raw that natural look those + + align:start position:0% +think of how raw that natural look those + + + align:start position:0% +think of how raw that natural look those +natural environments are in that's in + + align:start position:0% +natural environments are in that's in + + + align:start position:0% +natural environments are in that's in +that sequence and the extent to which we + + align:start position:0% +that sequence and the extent to which we + + + align:start position:0% +that sequence and the extent to which we +also so that the the film itself is in + + align:start position:0% +also so that the the film itself is in + + + align:start position:0% +also so that the the film itself is in +many ways a sub-theme in the film is the + + align:start position:0% +many ways a sub-theme in the film is the + + + align:start position:0% +many ways a sub-theme in the film is the +relationship between human beings and + + align:start position:0% +relationship between human beings and + + + align:start position:0% +relationship between human beings and +natural forces this scene implicitly + + align:start position:0% +natural forces this scene implicitly + + + align:start position:0% +natural forces this scene implicitly +sets that theme up without doing + + align:start position:0% +sets that theme up without doing + + + align:start position:0% +sets that theme up without doing +anything fancy or calling our attention + + align:start position:0% +anything fancy or calling our attention + + + align:start position:0% +anything fancy or calling our attention +to it what else does it do it defines + + align:start position:0% +to it what else does it do it defines + + + align:start position:0% +to it what else does it do it defines +the Mifune character really richly and + + align:start position:0% +the Mifune character really richly and + + + align:start position:0% +the Mifune character really richly and +fully he's something of a clown isn't he + + align:start position:0% +fully he's something of a clown isn't he + + + align:start position:0% +fully he's something of a clown isn't he +he likes attention he knew very there's + + align:start position:0% +he likes attention he knew very there's + + + align:start position:0% +he likes attention he knew very there's +something deeply theatrical about him + + align:start position:0% +something deeply theatrical about him + + + align:start position:0% +something deeply theatrical about him +see the way he he knew those that the + + align:start position:0% +see the way he he knew those that the + + + align:start position:0% +see the way he he knew those that the +other samurai were watching him and then + + align:start position:0% +other samurai were watching him and then + + + align:start position:0% +other samurai were watching him and then +when he when he caught but he's also + + align:start position:0% +when he when he caught but he's also + + + align:start position:0% +when he when he caught but he's also +what else do we learn about he's + + align:start position:0% +what else do we learn about he's + + + align:start position:0% +what else do we learn about he's +unbelievably competent he jumps in that + + align:start position:0% +unbelievably competent he jumps in that + + + align:start position:0% +unbelievably competent he jumps in that +freezing water and he catches a fish + + align:start position:0% +freezing water and he catches a fish + + + align:start position:0% +freezing water and he catches a fish +with his bare hands right and one + + align:start position:0% +with his bare hands right and one + + + align:start position:0% +with his bare hands right and one +implication of the scene may very well + + align:start position:0% +implication of the scene may very well + + + align:start position:0% +implication of the scene may very well +be that one of the things the muthoni + + align:start position:0% +be that one of the things the muthoni + + + align:start position:0% +be that one of the things the muthoni +characters trying to do is show the + + align:start position:0% +characters trying to do is show the + + + align:start position:0% +characters trying to do is show the +samurai how competent he is right and he + + align:start position:0% +samurai how competent he is right and he + + + align:start position:0% +samurai how competent he is right and he +led you to see Ben Healy ends up leading + + align:start position:0% +led you to see Ben Healy ends up leading + + + align:start position:0% +led you to see Ben Healy ends up leading +them to the villain of course you might + + align:start position:0% +them to the villain of course you might + + + align:start position:0% +them to the villain of course you might +guess do you think he remains excluded + + align:start position:0% +guess do you think he remains excluded + + + align:start position:0% +guess do you think he remains excluded +no of course not he ends up joining me + + align:start position:0% +no of course not he ends up joining me + + + align:start position:0% +no of course not he ends up joining me +he is the Seven Samurai and becomes the + + align:start position:0% +he is the Seven Samurai and becomes the + + + align:start position:0% +he is the Seven Samurai and becomes the +seventh as the film as the film goes on + + align:start position:0% +seventh as the film as the film goes on + + + align:start position:0% +seventh as the film as the film goes on +so we do so + + align:start position:0% +so we do so + + + align:start position:0% +so we do so +so the buffoon is nature is defined for + + align:start position:0% +so the buffoon is nature is defined for + + + align:start position:0% +so the buffoon is nature is defined for +us in in in action more than in words we + + align:start position:0% +us in in in action more than in words we + + + align:start position:0% +us in in in action more than in words we +have the theme of nature versus man + + align:start position:0% +have the theme of nature versus man + + + align:start position:0% +have the theme of nature versus man +have the broader definition of the + + align:start position:0% +have the broader definition of the + + + align:start position:0% +have the broader definition of the +nature of the samurai group itself and + + align:start position:0% +nature of the samurai group itself and + + + align:start position:0% +nature of the samurai group itself and +we get an action that also moves the + + align:start position:0% +we get an action that also moves the + + + align:start position:0% +we get an action that also moves the +story to a new location and exists this + + align:start position:0% +story to a new location and exists this + + + align:start position:0% +story to a new location and exists this +is the one reason that I find this + + align:start position:0% +is the one reason that I find this + + + align:start position:0% +is the one reason that I find this +example such a powerful one is that many + + align:start position:0% +example such a powerful one is that many + + + align:start position:0% +example such a powerful one is that many +people watching this movie never even + + align:start position:0% +people watching this movie never even + + + align:start position:0% +people watching this movie never even +remember this scene because it's hardly + + align:start position:0% +remember this scene because it's hardly + + + align:start position:0% +remember this scene because it's hardly +even though it is very dramatic scene + + align:start position:0% +even though it is very dramatic scene + + + align:start position:0% +even though it is very dramatic scene +isn't it + + align:start position:0% +isn't it + + + align:start position:0% +isn't it +the fact is there are so many + + align:start position:0% +the fact is there are so many + + + align:start position:0% +the fact is there are so many +astonishing dramatic visually memorable + + align:start position:0% +astonishing dramatic visually memorable + + + align:start position:0% +astonishing dramatic visually memorable +scenes in the film that almost most + + align:start position:0% +scenes in the film that almost most + + + align:start position:0% +scenes in the film that almost most +viewers who who don't have the advantage + + align:start position:0% +viewers who who don't have the advantage + + + align:start position:0% +viewers who who don't have the advantage +of having this scene singled out for + + align:start position:0% +of having this scene singled out for + + + align:start position:0% +of having this scene singled out for +them would never even remember it and + + align:start position:0% +them would never even remember it and + + + align:start position:0% +them would never even remember it and +that's exactly why it's so valuable it + + align:start position:0% +that's exactly why it's so valuable it + + + align:start position:0% +that's exactly why it's so valuable it +seems to me because it it plays a + + align:start position:0% +seems to me because it it plays a + + + align:start position:0% +seems to me because it it plays a +relatively minor role in the film its + + align:start position:0% +relatively minor role in the film its + + + align:start position:0% +relatively minor role in the film its +role in the film is fairly simple and + + align:start position:0% +role in the film is fairly simple and + + + align:start position:0% +role in the film is fairly simple and +structural but even in that simple + + align:start position:0% +structural but even in that simple + + + align:start position:0% +structural but even in that simple +two-and-a-half minute sequence a great + + align:start position:0% +two-and-a-half minute sequence a great + + + align:start position:0% +two-and-a-half minute sequence a great +deal is going on it's a wonderful + + align:start position:0% +deal is going on it's a wonderful + + + align:start position:0% +deal is going on it's a wonderful +instance it seems to me of what we mean + + align:start position:0% +instance it seems to me of what we mean + + + align:start position:0% +instance it seems to me of what we mean +by texture or multiplicity if you're + + align:start position:0% +by texture or multiplicity if you're + + + align:start position:0% +by texture or multiplicity if you're +aware of this principle when you look at + + align:start position:0% +aware of this principle when you look at + + + align:start position:0% +aware of this principle when you look at +other forms of art not just films I + + align:start position:0% +other forms of art not just films I + + + align:start position:0% +other forms of art not just films I +think you'll find your sense of what is + + align:start position:0% +think you'll find your sense of what is + + + align:start position:0% +think you'll find your sense of what is +going on in a particular text or a + + align:start position:0% +going on in a particular text or a + + + align:start position:0% +going on in a particular text or a +particular expressive form will be + + align:start position:0% +particular expressive form will be + + + align:start position:0% +particular expressive form will be +immensely enlarged and I hope you apply + + align:start position:0% +immensely enlarged and I hope you apply + + + align:start position:0% +immensely enlarged and I hope you apply +these ideas not just to movies in the + + align:start position:0% +these ideas not just to movies in the + + + align:start position:0% +these ideas not just to movies in the +future but to other but to other forms + + align:start position:0% +future but to other but to other forms + + + align:start position:0% +future but to other but to other forms +of expressive experience as well I also + + align:start position:0% +of expressive experience as well I also + + + align:start position:0% +of expressive experience as well I also +at the end of this course as at the end + + align:start position:0% +at the end of this course as at the end + + + align:start position:0% +at the end of this course as at the end +of every semester I'm afflicted by a + + align:start position:0% +of every semester I'm afflicted by a + + + align:start position:0% +of every semester I'm afflicted by a +sense of gratitude that I can't always + + align:start position:0% +sense of gratitude that I can't always + + + align:start position:0% +sense of gratitude that I can't always +fully Express to my students I've been + + align:start position:0% +fully Express to my students I've been + + + align:start position:0% +fully Express to my students I've been +doing this for a long time I was + + align:start position:0% +doing this for a long time I was + + + align:start position:0% +doing this for a long time I was +thinking as the class opened this + + align:start position:0% +thinking as the class opened this + + + align:start position:0% +thinking as the class opened this +afternoon looking out at your faces I + + align:start position:0% +afternoon looking out at your faces I + + + align:start position:0% +afternoon looking out at your faces I +real is one of the most amazing things + + align:start position:0% +real is one of the most amazing things + + + align:start position:0% +real is one of the most amazing things +about being a professor is that your + + align:start position:0% +about being a professor is that your + + + align:start position:0% +about being a professor is that your +basic clients stay young and they keep + + align:start position:0% +basic clients stay young and they keep + + + align:start position:0% +basic clients stay young and they keep +you young they keep you young even + + align:start position:0% +you young they keep you young even + + + align:start position:0% +you young they keep you young even +though they also in some ways make you + + align:start position:0% +though they also in some ways make you + + + align:start position:0% +though they also in some ways make you +more and more conscious of the gap + + align:start position:0% +more and more conscious of the gap + + + align:start position:0% +more and more conscious of the gap +between you and your students in some + + align:start position:0% +between you and your students in some + + + align:start position:0% +between you and your students in some +respects I have no doubt that part of + + align:start position:0% +respects I have no doubt that part of + + + align:start position:0% +respects I have no doubt that part of +what has made my career as a satisfying + + align:start position:0% +what has made my career as a satisfying + + + align:start position:0% +what has made my career as a satisfying +one and certainly what has made me a + + align:start position:0% +one and certainly what has made me a + + + align:start position:0% +one and certainly what has made me a +much much better teacher that I might + + align:start position:0% +much much better teacher that I might + + + align:start position:0% +much much better teacher that I might +otherwise have been + + align:start position:0% +otherwise have been + + + align:start position:0% +otherwise have been +has been the enthusiasm and welcoming + + align:start position:0% +has been the enthusiasm and welcoming + + + align:start position:0% +has been the enthusiasm and welcoming +interest that I've felt from virtually + + align:start position:0% +interest that I've felt from virtually + + + align:start position:0% +interest that I've felt from virtually +every student I've ever taught and + + align:start position:0% +every student I've ever taught and + + + align:start position:0% +every student I've ever taught and +that's been especially true in this + + align:start position:0% +that's been especially true in this + + + align:start position:0% +that's been especially true in this +course and it's been especially true in + + align:start position:0% +course and it's been especially true in + + + align:start position:0% +course and it's been especially true in +this semester so I want to end then by + + align:start position:0% +this semester so I want to end then by + + + align:start position:0% +this semester so I want to end then by +saying thank you in a way symbolically + + align:start position:0% +saying thank you in a way symbolically + + + align:start position:0% +saying thank you in a way symbolically +I'd like to say thank you to the + + align:start position:0% +I'd like to say thank you to the + + + align:start position:0% +I'd like to say thank you to the +students to the students I've been + + align:start position:0% +students to the students I've been + + + align:start position:0% +students to the students I've been +teaching for more than 35 years at MIT + + align:start position:0% +teaching for more than 35 years at MIT + + + align:start position:0% +teaching for more than 35 years at MIT +for whom you are stand-ins but most of + + align:start position:0% +for whom you are stand-ins but most of + + + align:start position:0% +for whom you are stand-ins but most of +all I want to thank you + + align:start position:0% +all I want to thank you + + + align:start position:0% +all I want to thank you +you make me teaching makes me feel + + align:start position:0% +you make me teaching makes me feel + + + align:start position:0% +you make me teaching makes me feel +serious being able to introduce students + + align:start position:0% +serious being able to introduce students + + + align:start position:0% +serious being able to introduce students +to these astonishing works of art has + + align:start position:0% +to these astonishing works of art has + + + align:start position:0% +to these astonishing works of art has +always has always seemed to me to be a + + align:start position:0% +always has always seemed to me to be a + + + align:start position:0% +always has always seemed to me to be a +privilege for which I was unable to + + align:start position:0% +privilege for which I was unable to + + + align:start position:0% +privilege for which I was unable to +express fully my gratitude so thank you + + align:start position:0% +express fully my gratitude so thank you + + + align:start position:0% +express fully my gratitude so thank you +very much have a wonderful life + + align:start position:0% + + + + align:start position:0% + +you \ No newline at end of file diff --git a/oTNwGuI7Wic.txt b/oTNwGuI7Wic.txt new file mode 100644 index 0000000000000000000000000000000000000000..b3dcc94cd7c02e0e796135137af174001026eb52 --- /dev/null +++ b/oTNwGuI7Wic.txt @@ -0,0 +1,2998 @@ +The following content is +provided under a Creative + +Commons license. + +Your support will help MIT +OpenCourseWare continue to + +offer high quality educational +resources for free. + +To make a donation or view +additional materials from + +hundreds of MIT courses, visit +MIT OpenCourseWare at + +ocw.mit.edu. + +PROFESSOR: Today I want to +talk a little bit about + +designing control systems. + +This will finish up +our discussions + +on signals and systems. + +Let me then just briefly +review where we are. + +Hopefully this might help you +also for perspective with + +regard to thinking about +the exam tonight. + +We've looked at a bunch +of different kinds of + +representations for discrete +time systems. + +The easiest, most concise method +we looked at was the + +representation using a +difference equation. + +That's mathematically as +concise as you can get. + +But it doesn't tell you +important things like who's + +the input and who's the output +and what are all the different + +ways that you can get +through the system + +from input to output? + +So for that question block +diagrams are nice. + +Block diagrams are graphical. + +It makes it very easy to see +when there is, for example, a + +cyclic path through +the network. + +But they're graphic. + +They're not nearly so concise +as difference equations. + +So then we went on +to operators. + +Operators are just as concise +as difference equations but + +they contain additional +information because the + +operators have an implicit +argument. + +So there's an input, which is +the argument to the operator, + +and there's an output, which is +the output of the operator. + +So you can tell who is the input +and who is the output. + +So that's good. + +That sort of combines the +strengths of difference + +equations and block diagrams. + +You end up with a concise +representation that has + +complete information about +the signal flow paths. + +Furthermore, you can analyze +the operators by using + +polynomial mathematics and that +gives rise to the notion + +of a system functional. + +And that's a very nice closure +because that represents an + +abstraction that lets us think +about a whole system as though + +it were just one part, one +thing, one operator. + +So we use that structure then, +all of those representations, + +to try to learn about +feedback. + +And first off, in the block +diagram it's very easy to see + +that any time you have feedback +-- feedback so + +enormously powerful that we want +to use it in design -- + +but you can see immediately +from the structure of the + +block diagram that if you have +feedback then you have cycles. + +Why is that interesting? + +Well, that's interesting because +if you have cycles + +then even transient inputs can +generate persistent outputs. + +So that's a kind of behavior +that we would like to + +understand. + +From the nature of feedback +it generates cycles. + +From the nature of cycles it +generates persistent responses + +even if there's no input. + +And we saw that we could +characterize those by thinking + +about those responses for +one part at a time. + +And those parts we thought of as +poles and the responses to + +a single pole we called modes. + +So we thought through a way of +decomposing the response of a + +complicated system in terms +of a number of additive + +components that are +based on poles. + +Poles are just the base of +a geometric sequence. + +So today then what I want to +do is use that framework to + +think about design. + +How would you optimize the +design of a controller? + +Looking back to where we've +been, way back in Lab 4, + +ancient history, we looked at +how you could program the + +robot to approach a wall. + +And we saw that depending on how +you set up that system you + +could get very different +performances. + +And what we'd like to do is have +a way that we can design + +for performance without +actually building it. + +The kind of thing that we built +in the lab, Lab 4, was + +so easy that building it to +determine its behaviors was + +not a bad problem. + +But In general if you were +building a 777, there's more + +than one pole. + +And you wouldn't necessarily +want to test drive all of the + +bad configurations. + +So we'd like to be able to +understand that kind of a + +problem analytically. + +We'd like to be able +to analyze it. + +So using the different +representations you can + +generate a very concise +representation just thinking + +in terms of difference +equations. + +You all did this in Lab 4. + +And you get a single difference +equation that tells + +you in principle everything +there is that you could know, + +but not in a form that's +very easy to analyze. + +It's a bit better if you +translate the difference + +equation into a block diagram +because now you can see that + +this system of equations +has in fact two + +feedback loops in it. + +Two cycles. + +Two things that might +potentially generate + +persistent responses to +transient signals, which could + +then degrade performance. + +If the transient signal lasts +ten years it might be a bad + +controller. + +If the 777 hits turbulence +and never stabilizes + +that would be bad. + +If small disturbances got bigger +with time that might be + +bad, right? + +So we can see that this simple +controller described by these + +difference equations has +the potential to do + +that sort of stuff. + +And we'd like to understand, +when does it? + +The easiest way to think about +analyzing this is to focus + +first on the inner loop and ask +the question, what's the + +functional representation for +that box which we would call + +an accumulator? + +This box, this thing, +accumulates at its output, the + +sum of all the things that ever +came in so we call it an + +accumulator. + +So what's the functional +representation of an + +accumulator? + +Well, we just do polynomial +math. + +Easy so we can recognize from +the block diagram that the + +signal Y could be constructed +by applying R to W. + +But we can also see in the block +diagram that W is the + +sum of X and Y. And then if we +take the left hand side and + +the right hand side of this +double equation we get + +something that involves just X +and Y, which we can solve for + +the ratio Y over X. Which then +says that the ratio is R over + +(1 minus R). + +That's a functional +representation for the effect + +of the accumulation. + +That's also something that comes +up so frequently in the + +design of control systems +that we give it a name. + +We call this Black's Equation. + +And it's especially useful to +avoid these little trivial + +steps in algebra, to just +jump to the answer. + +So let's see that everybody's +following me. + +The equation for this box is +the thing that we will call + +Black's Equation. + +It's not mysterious. + +It's something that you could +derive, so derive it. + +Figure out the functional form +for the system that goes from + +X to Y and figure out which +of these forms is correct. + +(1) through (4), or (5) if none +of the above applies. + +So take 30 seconds, figure +out the answer. + +I'm going to ask you +to raise your hand. + +You're free to talk +to your neighbors. + +OK. + +So everybody who raised your +hands tell me what the + +right answer is. + +OK, wonderful. + +It's about 95%. + +No. + +It's about 100% correct out of +about 95% participation. + +So the answer you can form just +like we did before, no + +particular tricks, using +simple algebra. + +Simple algebra you get +F over (1 minus FG). + +The thing I want you to +recognize is kind of a + +graphical way of thinking +about that. + +And you can just memorize +F over (1 minus + +FG) and that's fine. + +But there's some interesting +things that the designer + +thinks about. + +This functional form is F, +that's the forward gain. + +That's the gain through the +system starting at the input + +and going directly +to the output. + +So this form says that the +closed loop gain, the system + +function that results when the +loop is closed, is just the + +forward gain, F, divided by +(1 minus the loop gain). + +The loop gain is the product +around the loop once. + +So that's just a convenient +way of thinking about it. + +Any time you have a feedback +system of this type you can + +think about the closed loop +response as being the forward + +path F divided by (1 minus +loop gain FG). + +So the answer was 1. + +And generally we'll see two +different ways of representing + +the system. + +Sometimes we'll represent it +with a plus as we did with the + +accumulator. + +Many times we'll represent +it with a minus. + +That's the way we think about +control problems. + +We put in the minus because we'd +like to think about the + +controller as trying to make +something go to 0. + +So when you take the difference, +that gives us an + +error signal. + +And then we can think about the +controller being the thing + +that drives that error to 0. + +But however you think about it, +there's two forms that are + +very closely related. + +They really differ by just a +minus sign which you could + +think of as just multiplying +G. So it's sort of like the + +right hand side is just +a minus G plugged into + +the left hand side. + +So then the way you use this +idea, you think about the + +block diagram and you say, OK I +can replace this thing with + +an equivalent system +which is R over (1 + +minus R) and then repeat. + +So the R over (1 minus R) means +that, if you think about + +Black's Equation now for this +loop, you should think about + +the forward gain, K minus T, R +over (1 minus R), that's this. + +Divided by (1 plus +the loop gain). + +So 1 plus, and the loop gain, +well, the wire down here just + +has a gain of 1. + +So the loop gain and +the forward gain + +are the same thing. + +So you get this kind +of expression which + +simplifies to this. + +There's two things I want +you to see about this. + +First off, I want you to see +that even though the + +simple-minded way of plugging +in said that we should have + +got a quotient of quotients N +over D over N over D, it's + +simplified to a single ratio. + +If you design a system out of +just adders, gains and delays, + +that will always be true. + +There's a closure. + +It will always be the case +that the functional that + +represents a system of that +form will always have the + +property that it's a polynomial +in R divided by + +another polynomial in R, +that's just the way + +polynomials work. + +The other thing is that you +can now start to interpret + +what the behavior of this could +represent in a simpler + +form than thinking about this. + +So this kind of a representation +that leads to + +intuition about what the +behavior should be is very + +helpful when you're thinking +about design. + +And in particular this +particular thing says that if + +we think about a simpler system +that could generate + +that same response we can +generate some intuition for + +how we would like to set +the parameter k. + +So in particular this system +functional which we generated + +for this system could equally +apply to that system. + +Is that clear? + +So there's a numerator, which +I've represented here. + +There's a numerator, which +has an R in it and has + +a minus kT in it. + +I'm going to, for reasons that +you'll see in a minute, I'm + +going to call something P0 +because it's the pole. + +So the numerator I've +represented here and this + +denominator has this form. + +And I wrote it that way because +this is the canonical + +form for the way of thinking +about a pole. + +So what I showed is that even +though this was a more + +complicated system you can think +about it as the cascade + +of a delay, a gain, +and a pole. + +The pole can be calculated from +the gain, the pole is the + +multiplier for R, so the +pole is (1 plus kT). + +So if I were to choose kT to +be minus 0.2 then the pole + +would be at 0.8. + +If the pole is at 0.8 then the +mode, the natural response to + +the pole, would have the +form P to the n. + +They always have the form +geometric P to the n, so it + +would look like 0.8 to the n. + +Because of the pre-multiplier of +1 minus P0 the whole thing + +gets multiplied by 0.2 and +because of the delay the whole + +thing gets shifted +to the right. + +The important thing is that by +thinking about manipulating + +this as an operator we can +recognize and simplify the + +form of the behavior. + +That gives us an intuitive +grasp over how + +to best choose kT. + +It's all clear? + +Now, the behaviors that we're +interested in are not always + +unit-sample responses. + +We do unit-sample responses +because they're the easiest + +possible thing we could +think of, right? + +A unit-sample is the simplest +non-zero signal. + +A unit-sample is the signal that +is different from 0 in + +exactly one place -- + +the easiest possible place, 0. + +And it has its easy-as-possible + +non-zero value -- + +1. + +So we focus on the unit-sample +signal because it's the + +easiest possible signal +we could think about. + +But when we're thinking about +behaviors we're often thinking + +about other things. + +Often we'll think about +the step response. + +Here I have illustrated +the way you would + +measure a step response. + +A step response is what would +happen if the output were + +initially 0, if we were at rest, +and suddenly we turned + +on a signal that was +constant at 1. + +That would happen in the robot +case if we started the robot + +close to the wall, at +rest, near 0 -- + +so that the output signal is +close to 0, but the desired + +input was a meter behind. + +Then that would be an input +signal that started at time + +equals 0 equal to 1 and +persisted forever at 1. + +And the result then +would be what we + +call the step response. + +The step response is typically +easier to measure in the lab + +than is the unit-sample +response. + +So we use the unit-sample +response when we're thinking + +analytically, when we're doing +calculations, and we use the + +step response when +we're in the lab + +trying to measure something. + +And the whole theory wouldn't +be very useful if there + +weren't a close relationship +between those two things. + +This diagram illustrates +the relationship. + +If we think about a system H +for which we would like to + +find the step response, the step +response to that system + +is what would the system +do if you put the + +unit-step into the system. + +I've represented the unit-step +here as u[n]. + +u[n], the signal that is 0 for +n less than 0, and 1 for n + +bigger than or equal to 0 -- + +is just the accumulation of +the delta function, the + +unit-sample. + +So this system, the cascade of +an accumulator with H, would + +measure the step response of H +if it were driven with the + +sample signal. + +Because of the properties of +polynomials and because block + +diagrams follow the rules for +polynomials, we can flip these + +whenever the systems both start +at rest, and if we flip + +those we get a different +interpretation. + +What this says is that if you +were to take H and stimulate + +it with the unit-sample you +would get h, little h, which + +we would call the unit-sample +response because it's the + +response to the system when the +input is the unit-sample. + +So if you measured h with the +unit-sample rather then with + +the unit-step you would get the +unit-sample response from + +which you could generate the +step response by running it + +through an accumulator. + +So what that says is there's a +close association, there's a + +close relationship, between the +unit-sample response and + +the unit-step response. + +One is the accumulation +of the other. + +The unit-step response is the +accumulated response to the + +unit-sample response. + +So that means that in that +previous example where we saw + +that setting kT equal to minus +0.2 resulted in this + +unit-sample response, that +would correspond to this + +unit-step response. + +All you do is for every sample +you calculate, for this + +response you calculate the sum +of say, n equals 0, you would + +take the sum of all of the +previous answers in H[n]. + +It's the accumulation. + +So it starts at 0 since the sum +of all those numbers is 0. + +Then at time 1 it becomes the +sum from here back so it + +becomes 0.2. + +Then here it's the sum +from here back. + +And if you add these all up +it becomes a number that + +approaches 1. + +Not surprisingly, right? + +If you've got a feedback system +and if you started the + +robot up against the wall and +the desired position was one + +meter behind you would +monotonically approach 1, OK? + +And what you can see is that if +you change the value of the + +pole, here I've changed the kT +from minus 0.2 which is what + +the previous answer was, to +minus 0.8, I've changed the + +value of the pole, +the unit-sample + +response got faster. + +And the unit-step response +also got faster. + +The point is there are different +kinds of performance + +metrics that we might want to +use, unit-sample response, + +unit-step response, but the +responses of all of them, you + +can tell something about the +response to all of them from + +the response of the unit-sample +signal. + +That's why we focus so much +on the unit-sample signal. + +It's not because it's the +most popular thing + +to use in the lab. + +It's because it's the easiest +thing to calculate with and it + +gives us insight into things +that we would like to measure + +in the lab. + +So for this very simple system +what you can show is that + +there's only a few possible +behaviors, a few + +categories of behaviors. + +If you were to choose kT to be +between 0 and 1, then the + +pole, which is (1 plus kT) would +also be between 0 and 1. + +Since the system has a single +pole you can say a lot about + +the response from the numerical +value of the pole. + +If the pole is between 0 and 1 +then the response is going to + +be monotonic and converging. + +That results because the +unit-sample response was + +positive only and decayed +towards 0. + +Because it's positive only +it means monotonic -- + +goes to 0 and makes +it converge. + +So you can infer properties +about the unit-step's response + +from properties of the pole +just like we could infer + +properties of the unit-sample +response. + +If you changed kT to be between +minus 2 and 1 you get + +a P0 that's between +minus 1 and 0. + +Again that's just +that equation. + +That says that the response +will be alternating. + +So the sign of the unit-sample +response goes + +positive then negative. + +It still converges in the sense +that the unit sample + +response approaches 0. + +And what that means for the unit +step-response is that the + +unit-step response will +converge toward 1. + +The sign doesn't alternate +around 0, the sign + +alternates around 1. + +So again, you can infer the +properties of the unit-step + +response from the properties of +the unit-sample response. + +And if you have kT that is less +than minus 2 then you get + +a P0 that's less than +minus 1 and + +that's a divergent response. + +So the point is you can infer +properties about the control + +system by thinking about the +poles of the system where here + +I've illustrated it for +a simple system that + +only has one pole. + +OK. + +I told you a bunch of facts. + +Now you figure out something. + +How would I choose k for this +system to get the quote, "best + +performance?" + +So which value of kT would give +the fastest convergence + +for the unit-sample signal? + +OK, participation is down but +the hit rate is still good. + +Virtually everybody who +volunteered to answer got the + +right answer. + +The most popular +answer was (2). + +Why is the answer (2)? + +What's the range of +possibilities + +that we could get? + +If we choose k, or kT, we +could choose kT to be-- + +what's the range of kT +that we could use? + +Minus 2 to 0? + +[INAUDIBLE] we could use kT, +any real number, right? + +We couldn't use imaginary +numbers because that doesn't + +sort of make sense for +a real system. + +But we could choose +any real number. + +The real numbers map, according +to this chart, the + +real numbers map to a different +real number. + +If you choose kT you can figure +out where is the pole + +by that mapping. + +Where would you put the pole to +get the fastest response? + +If you have your choice of +putting the pole anywhere on + +this red line, that red line or +that red line, where would + +you put it and why? + +AUDIENCE: Just inside +the [INAUDIBLE] + +PROFESSOR: Putting it inside the +unit circle would probably + +be a good idea because? + +AUDIENCE: [UNINTELLIGIBLE] + +PROFESSOR: Yeah. + +If you didn't put it +inside the unit + +circle it wouldn't converge. + +That's right. + +So you like [UNINTELLIGIBLE] +the inside. + +Given the choice of anywhere +here and anywhere here which + +would you choose? + +How would you choose it? + +Yeah. + +AUDIENCE: Derive. + +PROFESSOR: Derive. + +And how do you get that? + +AUDIENCE: [UNINTELLIGIBLE] + +PROFESSOR: What would happen +if it was close to + +[UNINTELLIGIBLE]? + +It converges quite +quickly, right? + +Poles always converge +geometrically. + +The base of the geometric +is the pole value. + +So you'd like the pole to be +as small as possible to get + +the convergence as +fast as possible. + +That make sense to everybody? + +So in particular for this +example if you chose kT to be + +minus 1 in that limit then this +entire factor goes away. + +So the entire response +degenerates to R and R is not + +instantaneous but it's +pretty fast. + +What that says is that +you get to the final + +value in one step. + +So if the input consisted of +a unit sample, which has + +non-zero value only at 0, the +output would have non-zero + +value only at 1, right? + +Thinking about the way that +works in practice, think about + +the robot and think about +we're trying to + +drive toward the wall. + +If we made kT be minus one, and +just for the sake of being + +concrete let me say that +T is about 1/10. + +That's what the sampling period +is for the robots we + +use in the lab. + +If T were 1/10 then the best +k would be minus 10. + +And what that says is that if +we were 1 meter away from + +where we want to be we would set +the velocity to 10 meters + +per second. + +What that says is that if we +started 1 meter away from + +where we want to be, so this +is intended to represent + +position on the same axis that +this has showed, so if we + +started here and we wanted to be +here, time is plotted down. + +If we use the rule that we just +specified then we would + +set the velocity given this +condition which is 1 meter + +away from where we want to be. + +We would set the velocity +to be 10. + +If we set the velocity to be 10 +then after 1 unit of time, + +after 1/10 of a second, we are +1 meter to the right, which + +just happens to be exactly +where we want to be. + +Had we chosen k to be bigger +we would have overshot. + +Had we chosen k to be smaller +we would have undershot. + +k equals 10 gave us precisely +the right answer so that we + +get there in one fell swoop. + +Then on the very next step we +would compute a velocity of 0 + +because we are at where +we want to be so + +we would stay there. + +And that condition would +persist forever. + +The idea would be this simple +system provides a way that we + +could set the gain so we could +get to where we want + +to be in one step. + +It's hard to beat that. + +The problem that results and the +reason you didn't see that + +good behavior in the lab was +that the sensors in the robot + +don't work instantaneously. + +They introduce delay. + +And as an idealization of that +delay I want to think through + +the same problem. + +But now let's say that the +sensor delays the input to the + +sensor which is the output +of the system. + +Let's say that the sensor +introduces a delay of 1, so + +now instead of reporting d +sensed, which was d0[n], it + +reports d0[n minus 1]. + +So now what would happen? + +Now with the delay, if I started +here and if by some + +mysterious process I was here +at time n equals 1, then I + +would calculate my +new velocity. + +What would be my new +velocity here? + +I'm right where I want to be. + +What would be my new velocity +if I assume that the sensor + +has a delay of [UNINTELLIGIBLE]? + +AUDIENCE: 10. + +PROFESSOR: 10. + +Because of the delay the sensor +is reporting that I'm a + +meter away from where +I want to be. + +So the controller calculates, +oh, I need to + +go forward a meter. + +I'll set the velocity to 10. + +So having set the velocity to 10 +and then one step goes by, + +now we're completely +on the wrong side. + +That's what happens when you +put delay into the system. + +So because we're basing this +decision on where we were last + +time we go to the wrong place. + +So now we're here. + +What will the controller +say next? + +AUDIENCE: [UNINTELLIGIBLE] + +PROFESSOR: Stay here. + +You're in a great place. + +I'm really 1 meter too close. + +In fact I banged +into the wall. + +But the sensor is telling me I'm +exactly where I want to be + +so stay here. + +Say I didn't kill myself, what +will the velocity next be? + +Minus 10. + +So now I tell myself +to go back. + +That's probably a good move. + +But now I still think I'm too +close to the wall so I tell + +myself to continue to back up. + +The idea is that I get +poor performance. + +The delay had a devastating +effect on the way that the + +controller worked. + +Even though it's a tiny change +to the way the system works it + +has a devastating effect +on behavior. + +We'd like to be able to predict +that without having to + +measure it. + +Here's the same equations except +that I put a delay in + +the sensor. + +Here is the same block diagram +but I've represented a delay + +in the sensor path. + +So now the question is, what's +the new functional + +representation for that +control system? + +So what's the answer? + +Can you rate the functional form +for this system as one of + +(1), (2), (3), or (4), or +is it none of the above? + +About 1/3 participation and +about 100% correct. + +The answer's four. + +You get to use Black's Equation +or however you'd like + +to think about that. + +You can think about reducing the +inner loop the same as we + +did before and then think about +this as forward over (1 + +plus loop gain) but now the loop +gain has R squared in it + +instead of R. We +get this form. + +How does this form differ from +when the R wasn't here? + +What's the difference between +R not there and R is there? + +What's the answer? + +Anyone? + +AUDIENCE: [UNINTELLIGIBLE] + +PROFESSOR: The squared term. + +So this term in the previous +form was just an R and in this + +form is a square and +so what's that do? + +What's the importance +of the fact that + +there's a square there? + +Two poles, right? + +We now have a polynomial in +the denominator that is + +quadratic in R. + +And what that's going to do is +it's going to give us two + +poles instead of one. + +The importance of that is that +now we're going to have to + +think through-- we previously +categorized what were all the + +behaviors you could +get from one pole. + +The behaviors you can get from +one pole were monotonic + +divergence, non-monotonic +alternating divergence, + +monotonic convergence, +alternating convergence. + +So there were four behaviors +that were + +possible with one pole. + +Now we have to think through +what are all the possible + +behaviors that we could +get with two poles. + +Different problem. + +Hopefully they're related. + +So here, the way we would find +out what the poles are is take + +this expression, substitute for +every R, 1 over z, turn + +the ratio of polynomials +in R into a ratio of + +polynomials in z. + +To do that in this case I had +to multiply numerator and + +denominator by z squared. + +Having done that I get a second +order polynomial in z + +in the bottom so there's two +poles which are the roots of + +that polynomial. + +And that's just a quadratic +equation. + +The interesting thing now is +to map out what are all the + +possible behaviors that that +system can give us. + +It's important to realize that's +a simple generalization + +of what we saw before. + +It will be the case that any +system that we construct out + +of adders, gains and delays will +have the property that we + +can write the system functional +as a ratio of + +polynomials in R. By the factor +theorem we will always + +be able to factor +the denominator. + +And by the notion of partial +fractions we'll always be able + +to write some complicated +expression like that in terms + +of a sum of parts. + +Each part being first order. + +The intuition we get from this +is that what we ought to do is + +factor the denominator, find +the poles, and associate a + +behavior with each +of those poles. + +Here's what the problem looks +like for the two pole problem. + +If we have the general form +given here and if we start by + +thinking about kT having a small +magnitude, if kT has a + +small magnitude then we have 1/2 +plus or minus the square + +root of 1/2 squared. + +So that's 1/2 plus +or minus 1/2. + +That's 0 or 1. + +So the poles for this system, +if you make k be very small, + +the poles are at 0, +near 0 and near 1. + +Is that a good system response +or a bad system response? + +Bad. + +Why? + +Well, we're trying to think +through the behavior of the + +second order system by thinking +about the separate + +behaviors of each +of the poles. + +Is this a good pole +or a bad pole? + +Why? + +The response is always pole +[UNINTELLIGIBLE]. + +The mode associated with the +response at a pole near one is + +something near one to the end. + +That never converges. + +If you start with some error +the error persists forever. + +Well, that's not good. + +If wind turbulence knocks you +into a decline in your + +airplane and it persists +forever, that's not good. + +You would like those +things to damp out. + +So this pole is bad. + +How about that pole? + +That one has a response +that decays quickly. + +But the problem is that when +you add the two pieces + +together, that was the reason +I showed you this + +decomposition, you can think +about the polynomial being + +factored and being broken +into a number of parts. + +The part that's associated with +the pole near one has a + +response that goes +for a long time. + +So that will asymptotically +dominate your response. + +So we refer to this as +a dominant pole. + +This pole dominates +the response. + +That's a way of inferring the +behavior of two poles from the + +sum of single poles. + +In this particular case there's +one pole that matters + +more than the other one. + +So we call that pole +the dominant pole. + +If you were to make kT more +negative, So here's the + +general form. + +If you make kT negative, you can +make the thing under the + +radical sign go towards 0. + +If you made the thing under the +radical sign go to 0 then + +you would get two +poles at 1/2. + +So here we would see that if kT +were minus 1/4, if kT were + +minus 1/4 we would have 1/2 +squared, which is plus 1/4. + +Minus 1/4 would give us +0 under the radical. + +So we would get two +poles at 1/2. + +Is that good or bad? + +Well, it's better than the +previous example, right? + +Because each of those poles is +associated with the response + +where the error gets half what +it used to be on every step. + +So it converges. + +If going from 0 to minus 1/4 is +good, then going to minus + +1/2 might be better, right? + +If you continue that trend, say +you make kT be minus 1, if + +kT is minus 1 then you get +1/2 squared minus one. + +So 1/2 squared is 1/4, minus +1 would be minus 3/4. + +That gives us a complex +pole here. + +So we get two poles that are +right on the unit circle. + +What's that mean? + +That means oscillations. + +Oscillations is something you +can't get with one pole with a + +real system. + +Oscillations result from +a poll that has + +an imaginary component. + +If the system is real +you could only get + +such poles in pairs. + +So it's this pair that +makes sense for + +a real valued system. + +And that gives rise to +oscillations and that's + +exactly what we saw here. + +So we can associate the +oscillations that we saw in + +the simulated lab experiment +with poles that have imaginary + +components. + +So what would be the period of +the oscillation in the system + +given by 1/2 plus +j root 3 over 2? + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: Excuse me? + +Excuse me? + +AUDIENCE: Where did the +root three come from? + +PROFESSOR: The previous page. + +If you substitute minus 1. + +So what's the period +of the oscillation? + +So the period's represented +by 5 converged into 6. + +So how do you get 6? + +The easiest way to think about +that is to think about the + +poles being expressed +in polar notation. + +The poles we previously said +were 1/2 plus or minus + +j root 3 over 2. + +That's the same as e plus +or minus j pi over 3. + +It's easier to use that form +because if you take that form, + +so if you think about e to the +j, what was it, 2 pi over 3? + +Pi over 3. + +So if you think about that form, +that's the pole, we can + +write that that way. + +Then the inside has +a magnitude of 1. + +So we can think about that just +being a magnitude of 1 + +and an angle of pi over 3. + +So when you raise that to the n, +the magnitude to the n, one + +to the n is always 1, and the +angle raised to the n, it just + +increases linearly with n. + +So the angle goes from pi over +3 to 2pi over 3 to pi to 4pi + +over 3, et cetera. + +So you can think about this +going from pi over 3, 2pi over + +3, pi, 4, 5, 6. + +It takes n equals 6 to get +around to where it started so + +the period is 6. + +If you were to further change +the game, if you were to make + +it even more negative, the poles +would go outside the + +unit circle. + +And then what would happen? + +AUDIENCE: [UNINTELLIGIBLE] + +PROFESSOR: Right. + +So that's completely +unacceptable. + +The point is that by changing +the gain you can get any + +behavior on this figure which +is called the root locus. + +So root meaning the root +of a polynomial. + +Locus meaning the acceptable +values of points. + +So the root locus shows you +all the possible behaviors + +they could result from +this system. + +So given that root locus, how +would you choose k to make + +your system response as +fast as you could? + +So what value of kT +would you want? + +Everyone raise your hands. + +That's very good. + +So the most popular answer +is number (2). + +So why would the answer +be number (2)? + +What do you look at? + +Yeah? + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: Remember what +we're trying to do. + +We're trying to infer properties +of the behavior of + +this second order system from +the pole locations. + +We know that there's an +expansion that lets us expand + +the system in terms of the sum +of two first order responses. + +The slowest of the first order +responses will dominate + +eventually. + +So what we need to +look at is the + +slowest of the two responses. + +We would like to know +of the two poles + +which one is the slowest? + +The slowest is the one that's +closest to the unit circle. + +So we would get the fastest +response when the slowest one + +is as fast as possible. + +As the poles initially go toward +each other from 0 to 1 + +this one is getting faster, this +one is getting slower. + +So the slowest one +is this one. + +So the slowest one is fastest +when they meet. + +And then when they diverge +does the slowest one get + +faster or slower? + +It's already slower +because it gets + +closer to the unit circle. + +So you get the fastest response +whenever you get the + +two poles both colliding at 1/2 +and that was the case that + +happened when kT was minus 1/4 +from two or three slides ago. + +So the idea then is to try to +infer what would be the + +behavior of this higher order +system by thinking about the + +behaviors of the individual +components, here the poles. + +And what we saw was something +that's in fact a very + +important general trend. + +What we saw was that we first +analyzed the wall finder + +system assuming there was +no delay in the sensor. + +And we found that that system +was characterized by a single + +pole and we had the design +freedom of putting that pole + +anywhere we wanted to +on the real axis. + +And that allowed us to choose +the pole to be at 0 which gave + +terrific performance. + +The interesting thing that +happened when you add just one + +more pole by putting a delay +in the sensor, you make the + +system more complicated and +now you can't possibly get + +nearly so good behavior. + +The behavior is a lot worse +than it was before. + +And in fact, if you were to do +the same kind of analysis by + +putting yet another delay in the +sensor you would find even + +worse behavior. + +The idea then, the +generalization of the way the + +behaviors is working, generally +speaking adding + +delays inside a feedback loop +is a destabilizing thing. + +Generally as the number of +delays increases you end up + +having to back off on the +maximum gain that you can use + +because the system becomes +less stable. + +So the overall moral is that +delays are bad generally. + +I mean, you could concoct some +kind of a weird scheme where + +that wouldn't be true. + +But it's actually hard to +concoct such a weird scheme. + +In general, and in virtually +every physical system that + +you'll run into, adding +delays makes the + +system harder to stabilize. + +And that's the big message. + +And the system that we looked at +in the lab, the wall finder + +was actually quite hard +because the number + +of delays was large. + +If you try to track where delays +can enter the robot + +system they get in at very +many different places. + +In the physical sensor, in the +microprocessor, in the + +conversion from analog to +digital, there's a number of + +delays in that system. + +And that's why it becomes +hard to stabilize. + +OK. + +So that's the main content +for today. + +What I want to do is give you +one more practice question. + +The big problem that I want you +to think about from today + +is how do you characterize +performance? + +When we had a single pole +performance was easy to talk + +about because performance was +diverging monotonically, + +diverging alternating, +converging monotonically, + +converging alternating. + +There were four kinds +of behaviors. + +When we went to second order +we saw some new behaviors. + +It could become oscillatory. + +What I'd like you to do now is +think not just about those + +properties but many +other properties. + +So here's some questions. + +Think about the system on the +top and I'd like you to infer + +properties about that system. + +In particular, does this system +have three poles? + +Is the unit sample response, is +there a way to write that + +as the sum of three geometric +sequences? + +What's the unit sample +response? + +And is one of the poles +that z equals 1? + +So think about the system, +think about five ways of + +characterizing it and tell +me how many of those five + +characterizations is correct. + +So how many of the properties +are true? + +AUDIENCE: [UNINTELLIGIBLE] + +Probably 2/3 correct? + +PROFESSOR: How many poles? + +How do you get three? + +Where are the poles? + +AUDIENCE: [UNINTELLIGIBLE] + +PROFESSOR: How do +I find poles? + +What do I do? + +Yes? + +AUDIENCE: You use Black's +Equation [UNINTELLIGIBLE] + +the top you can express +[UNINTELLIGIBLE] + +so use Black's Equation to +express the system function as + +R cubed over (1 minus +R-cubed) then-- + +PROFESSOR: That's right. + +AUDIENCE: --the denominator +as an order of 3 and + +you combine the 3s. + +PROFESSOR: So a little more +formally, we would take this + +thing and we would rewrite that +with R goes to 1 over z. + +So we get 1 over z cubed, 1 +minus (1 over z cubed), which + +is then, clearing the z cubes +we would get 1 over + +(z cubed minus 1). + +How many poles? + +Three. + +What are the poles of +z cubed minus 1? + +Three poles in what? + +AUDIENCE: 0 [UNINTELLIGIBLE] + +PROFESSOR: And so let's vote. + +Let's take a vote. + +There's two poles +at z equals 1. + +Yes? + +No? + +AUDIENCE: [UNINTELLIGIBLE] + +PROFESSOR: Why not? + +AUDIENCE: [UNINTELLIGIBLE] + +PROFESSOR: So there's +two poles. + +I made a [UNINTELLIGIBLE] +plane. + +Where's the poles? + +Well, you could factor +it, right? + +If you factored it you'd +find that there is + +a pole at 1, right? + +But then there's two more +poles like that. + +So the poles are the three +roots of 1, which can be + +written like 1 e to the j, 2pi +over 3, and e to the j minus + +2pi over 3. + +Which pole was the +dominant pole? + +AUDIENCE: [UNINTELLIGIBLE] + +PROFESSOR: OK, bad question. + +What's a better question? + +AUDIENCE: How many dominant +poles are there? + +PROFESSOR: How many dominant +poles are there? + +That's a much better +question, yes. + +There's sort of three +poles that are + +equally dominant, right? + +They all have the +same magnitude. + +Why do we talk about +dominant poles? + +What are dominant +poles good for? + +If I told you that I had a pole +at 3 and a pole at minus + +1, which one's the +dominant pole? + +AUDIENCE: 3. + +PROFESSOR: Why? + +AUDIENCE: Greater magnitude. + +PROFESSOR: Greater magnitude. + +Why do we care? + +We don't care, right? + +What's good about the +dominant pole? + +Well, we can write this response +as something that + +looks like three to the n +plus minus 1 to the n. + +If you let n get big enough +the only one that + +matters is 3 to the n. + +So if all you care about is +exactly how the plane was + +flying the instant before it hit +the ground then you would + +only need to worry +about long time. + +And if you only worry about +long time you only need to + +worry about the pole that's +worst behaved. + +That's where the concept +comes from. + +So none of these poles are +particularly worse behaved + +than the others. + +What's the unit-sample response + +associated with that pole? + +We have a name for that +[INAUDIBLE] right? + +AUDIENCE: It's huge. + +PROFESSOR: It's +[UNINTELLIGIBLE]. + +What's the unit-sample response + +associated with this pole? + +Well, it's got a complex +value right? + +So the unit-sample response +associated with that pole is e + +to the j 2 pi over 3 n. + +That's a complex number. + +That's 1 at time 0 and e to the +j 2 pi over 3n at time 1 + +and e to the j 4 pi over +3 at time two. + +So it goes from here at 0 to +here at 1 to here at 2,3, 4, + +5, 6, 7, 8. + +What's the period +of this pole? + +What's the period of the +unit-sample responses + +associated with that pole? + +3. + +Because it takes 3 +to get around to + +where you started again. + +What's the period +of this pole? + +3. + +You just spin around backward. + +What's the period +of the response + +associated with that pole? + +Bad question. + +All right, what's a +better question? + +Is there a period associated +with it? + +You could say that period +1 [UNINTELLIGIBLE] + +definition of period. + +What's the period +of this pole? + +Dumb question, right? + +Period implies repeat. + +If the response repeats itself +after some time then we would + +say the response is periodic. + +Neither of those poles, +well, the minus 1 is. + +Is the minus 1 pole periodic? + +Yes. + +What's the difference between +periodic and alternation? + +Does a [UNINTELLIGIBLE] + +alternate? + +AUDIENCE: Yes. + +PROFESSOR: Does it oscillate? + +AUDIENCE: No. + +PROFESSOR: Bad question. + +Alternate is a word that we +invented for one pole. + +Because the response +alternated in sine. + +The unit-sample response in one +pole, where the pole is a + +negative number, alternated +in sine. + +So we gave that a name. + +Alternation is not necessarily +something that we would like + +to associate with a higher +order system. + +Periodic is perfectly reasonable +to talk about for a + +higher order system. + +Periodic merely means that if y +of n were a periodic signal + +that I could express y of +n plus n as y of n. + +That would be periodic. + +If the thing repeats itself we +would say it's periodic. + +So the point of going over this +stuff is just to give you + +some exercise in thinking +about how to think about + +properties of systems. + +We develop properties initially + +thinking about one pole. + +Those properties were easy. + +Converging, diverging, +monotonic, alternating. + +When we try to think about +corresponding properties of + +higher order systems we can't +simply map the simple + +properties of first order +systems into the other. + +We have to think about more +complicated things. + +Then we think about things +like dominant. + +If one of the poles has a bigger +magnitude than the + +other then for large times we +can ignore the smaller one. + +What happens for short time? + +Does this response monotonically +increase with + +time for all time? + +No. + +Since the response associated +with minus 1 alternates in + +sine, for short times, for times +with n close to 0, that + +can be just as important +as this one. + +So the dominant pole idea tells +you how things work when + +you have large times. + +It doesn't necessarily tell you +how things work when you + +have small times. + +How about, the unit sample +response is the sum of three + +geometrics. + +Yes or no? + +What are the three geometrics? + +And the answer to that's yes. + +That's very important. + +The three geometrics over here +are this pole to the n plus + +this pole to the n plus +something that goes with this + +other pole to the n. + +Now it's a weighted sum but +the weights are not + +necessarily 0. + +The slide that I showed you +for the partial fraction + +decomposition, you can always +write a higher order system as + +a sum of first order factors. + +That's the partial fraction +expansion. + +That doesn't mean the weights +are all unity. + +Number (2), can you write the +unit-sample response as the + +sum of three geometric +signals? + +Yes. + +There it is. + +And if you're really good at +complex math you could find + +out a, b and c. + +And that would tell you the +unit-sample response and that + +would tell you the answer +to (3) and (4). + +Is the unit-sample response 0, +0, 0, 1, 0, 0, 0, 1, 0, 0, 0, + +1, 0, 0, 0, 1? + +Or 1, 0, 0, 0, 1, 1 -- + +whatever. + +Is it one of those two or +something different? + +And how do you figure it out? + +How do you figure +out the unit? + +Is the unit-sample response-- + +Is number (2) correct? + +Is the unit-sample response +0, 0, 0, 1, 0, 0, + +0, 1, 0, 0, 0, 1-- + +Yes? + +How do you know that? + +You could solve that equation. + +Is there an easier way? + +Yeah? + +AUDIENCE: I wrote it as +a difference equation. + +PROFESSOR: Just write the +difference equation. + +Exactly. + +So even though I bad-mouth +difference equations a lot, + +here it's easy. + +In fact, you can see +it in the network. + +Thinking about the difference +equation would be easy. + +Thinking about the network +would be easy. + +If we think about the +unit-sample response of this + +thing started at rest, rest +means this is 0, this is 0, + +and this is 0 initially. + +Unit-sample response means +this becomes 1 at time 0. + +At time 0 this is 1, this is +0, this is 0, this is 0. + +So if I think about what's the +time response look like and I + +did plus, this is +0, 1, 0, 0, 0. + +The first answer is 0. + +Clock ticks. + +What happens? + +This is 1. + +This becomes 1. + +This doesn't change. + +That doesn't change. + +This goes to 0. + +0 comes around here. + +That goes to 0. + +So that's the answer +at time 1. + +What happens at time 2? + +Just keep working it. + +The clock ticks, this goes to 1, +this goes to 0, these stay + +0, this stays 0. + +That's the answer at +time equals 2. + +Now the clock ticks. + +Now this comes over to here, +that means it comes back here. + +This is still 0. + +That comes to 1. + +That's the answer for time 3. + +Now the clock ticks. + +And you can see the whole +thing would just + +repeat itself now. + +Is the response periodic? + +Yes. + +The response is periodic. + +What's the period? + +3. + +And I can see [INAUDIBLE] if +the [INAUDIBLE] there it's + +going to have be related to +the period over here. + +These periods are not same. + +This period is 3, this period is +3, this period is 1, if you + +want to call that a period. + +But they are related. + +OK. + +The point of this exercise is +to illustrate two things. + +We inferred properties of first +order systems by looking + +at a single pole which for a +real system could only behave + +in one of four different ways. + +Second order system introduced +new behaviors. + +Now we can oscillate, which +we couldn't do before. + +Having got to oscillation, +oscillation came about because + +of complex numbers. + +If you go to higher order +systems nothing + +new happens in algebra. + +There's no such thing as +meta-complex numbers, right? + +Complex is as bad as it gets. + +So you can have complex +numbers. + +The higher order behaviors can +still have complex numbers but + +you have to think when we ask +you, what's the property of a + +higher order system. + +You can think about it in terms +of the individual parts + +but it requires some thinking. + +OK. + +Good luck tonight. + +See you then. \ No newline at end of file diff --git a/p5ro4x1r16Q.txt b/p5ro4x1r16Q.txt new file mode 100644 index 0000000000000000000000000000000000000000..ab2c0cd47e1a13180326789472a34e8d95262cdc --- /dev/null +++ b/p5ro4x1r16Q.txt @@ -0,0 +1,2920 @@ +The following content is +provided under a Creative + +Commons license. + +Your support will help MIT +OpenCourseWare continue to + +offer high quality educational +resources for free. + +To make a donation or view +additional materials from + +hundreds of MIT courses, visit +MIT OpenCourseWare at + +ocw.mit.edu. + +PROFESSOR: We ended last time +kind of without really a + +resolution in the sense that we +looked at this example of + +these vendors in India and the +Philippines, and these vendors + +were somehow-- + +they seem to be unable to save +their way out of something + +that seems extremely costly +to keep bearing. + +They were paying 5% a day, and +even when somebody paid down + +their entire debt so that they +didn't have to borrow any + +more, they slipped back into +debt within about three weeks. + +So it was a sense in which these +people seem to find it + +difficult to stay out of debt +and, in particular, to hold + +onto their savings. + +So here's another experiment, +which sort of brings out some + +more off it. + +It's in Busia, Kenya, a +letter missing there. + +So the way it started +is that-- + +the experiment is by Esther +Duflo, Michael Kremer, and + +John Robinson. + +What they had done was they +started by actually giving + +farmers some fertilizer. + +One of the enduring kind of +puzzles in agricultural and + +economics is why farmers in +Africa don't use more + +fertilizer given that fertilizer +is something that + +basically makes money +for people. + +So why don't they use +fertilizer, and their various + +possible answers would +talk about those. + +But to demonstrate that it +really does seem to work-- + +what they started by doing is +making sure that it's true + +that it works, so what they did +was they had people give + +farmers fertilizer and told +them, this is your plot, just + +go ahead and use fertilizer, +and they give them free + +fertilizer. + +So they took a bunch of plots +and gave them free fertilizer. + +So very simple, you give people +free fertilizer, they + +do use it, not surprisingly, +especially if you make sure + +they can't sell it, and +they do use it. + +When they use it, +their incomes go + +up by 27%, and that's-- + +Oh, their incomes go +up by 27%, which is + +100% increase annually. + +So that's like three months, +three months, you bought the + +fertilizer, you laid it in the +ground, you waited for three + +months, you would get +27% more back. + +So they were pretty convinced +that fertilizer was a very + +useful thing to use. + +And this, they did it many +times, so it varies. + +Fertilizer is, in fact, +not predictable. + +Sometimes it works better than +others, but the range of these + +returns, where you never got +less than 80%, I think, + +basically, on your money, and +that's a very good investment + +if you get 80% on your money. + +Sometimes, you get 500%, but +even if you got a 80% on your + +money, that would be +a good investment. + +So question is why +don't they do it? + +So the various theories, +obviously, on why + +people don't do it. + +One is that they don't +know about it. + +That seems implausible, partly +because fertilizer's not a new + +technology. + +It's been around for +a very long time. + +And second, because take those +farmers who were given free + +fertilizer. + +They used it, they got 100% +return, annualized return, go + +back to those people at the +end of the year and the + +beginning of next season and +ask them do you want to use + +fertilizer. + +98% say yes, of course, we +want to use fertilizer. + +Only 37% actually use it. + +So these are people who clearly +know fertilizer works + +because they did it. + +It worked. + +There's no two ways about the +fact that they know it + +because, the fertilizer, they +had used it, they saw the + +results, they saw +it's working. + +Why didn't the farmers who had +seen that the fertilizer + +generates these massive returns +not go back to using + +fertilizer? + +Yeah? + +AUDIENCE: Beause they said +couldn't really afford it, and + +then also the fact was when +they did have the money, + +fertilizer generally +wasn't there. + +And when they didn't have +the money it was there. + +So it's difficult. + +PROFESSOR: OK, so that's +sort of the-- + +but before we come there, +lets rule out some other + +explanations. + +So one other explanation is +credit constraint, so we + +already discussed it's hard +for the poor to borrow. + +Interest rates are very high. + +That would be a good explanation +if fertilizer were + +indivisible, so if you had to +use a certain minimal amount + +to make money. + +But fertilizer is extremely +divisible. + +You can buy it in like You could +buy 500 grams of it, put + +it on a small plot, and +you'll make more money + +on that small plot. + +If you bought two kilos, +you make more + +money on a bigger plot. + +If you bought 10 kilos, +you'd have even more. + +So the question is why don't +people use fertilizer? + +If they have less money, +why don't they use it + +on a smaller plot? + +It's not enough to say that they +don't have money because + +money just-- + +if you're less money, you +can use it on less land. + +The main point is that whenever +you use it, you make + +money, so even if you use it on +a smaller plot, the output + +on that plot would still go up +by a lot, and the returns + +would be 100% a year on +the money you put in. + +Yeah? + +AUDIENCE: So I understand what +you're saying, but on the + +other hand, they can only afford +to fertilize a very + +small amount of land, that their +returns might just not + +be worth it to make this +tiny investment. + +You would have to wait for +several months to get an extra + +several rupees whereas you have +this money now, you might + +as well spend it now +[INAUDIBLE]. + +PROFESSOR: I guess that might +be right, but it's sort of-- + +in the end, it's why aren't they +thinking, look, it's 100 + +Kenyan shillings now. + +I'm going to get 200 +in three months. + +If it's 100 shillings, and +that's very little, that's a + +dollar and a bit, it's still +you get twice as much. + +So why aren't people thinking +in proportion? + +Why aren't they thinking that +twice as much is a lot more? + +Yeah? + +AUDIENCE: Wouldn't fertilizer +be more viable for bigger + +farmers because they have +irrigation, which is required + +for fertilizer to really work. + +PROFESSOR: Not in +Kenya, actually. + +I mean, fertilizer is-- + +it's true that it would +be more useful. + +But mostly even, Kenya +has especially-- + +this is the what they call +the short rain season. + +Most of agriculture in the short +rain season is rain fed, + +so I think people don't-- + +it's true that I'm sure +fertilizer would reduce risk, + +but there isn't much of risk. + +Even when the rains are not +great, you still make money. + +So if you ask farmers, they do +tell you the answer that they + +don't have any money. + +So they're answer is we +don't have any money. + +It's exactly what you +said, which is that + +they don't have money. + +Well, how would we +buy fertilizer? + +The fact is that, as you'll see +in a minute, they do have + +money, especially when +they harvest. + +Farming is a cyclical +business. + +You make money at some point. + +You plant, you wait for three +months, your crops come out, + +you sell your crops, +you get money, then + +you wait for a while. + +You buy some seeds. + +You plant again, so it's +kind of a cycle. + +So if you think of the point +when they have sold the crops, + +they certainly, at that point, +certainly do have money. + +It's not true that they don't, +and we'll see in a minute + +evidence that they +do have money. + +And in particular, +they seem to-- + +I mean, even if they can't save +all of it because they + +need to eat most of it, they +could have saved a little bit + +of it, so they could have +saved the money. + +Alternatively, they could just +buy fertilizer then, when they + +have the money. + +Fertilizer it is very durable. + +You just buy fertilizer. + +You keep it in a bag. + +It'll stay for three months. + +It's not that you need to buy +fertilizer on the day when you + +need to go farming. + +You could have bought fertilizer +ahead of time and + +kept it in your home. + +So we'll see that they do have +money at some point, and when + +they do have money, they +don't necessarily buy + +fertilizer with it. + +In fact, they did a small +survey, and they asked did you + +buy fertilizer at harvest +time when you had money. + +The answer is, no, almost +no one did that. + +So if you look at the +population, about 30% of them + +use fertilizer at any point of +time, but of that 30%, only + +about 3% had bought it early +when they had money. + +Most of them bought it at the +point of planting, so they had + +either managed to save +or they had borrowed. + +But in any case, they had-- + +[INAUDIBLE] + +Let me remove Skype. + +Yep. + +So what is true is that, so +basically, no one buys + +fertilizer early even though-- + +if you think that it's +a problem to-- + +maybe you don't have money at +planting time, then you should + +just buy it early. + +So here's a nice experiment, +which is sort of exactly + +trying to figure out what's +going on here. + +So what they did was they went +to different farmers, and + +since some farmers had already +had some experience using + +fertilizer and others had not, +they stratified by that. + +What does it mean to stratify? + +AUDIENCE: [INAUDIBLE]. + +PROFESSOR: Right, they're +randomized within the group of + +people who had used it before, +and within the group of people + +who had used it before. + +So they divided up the +population and randomized + +within each group, and then they +came to the household and + +offered them fertilizer and +said, look, you pay for it. + +We will sell it to you, and +we'll bring it to you so you + +don't have to go to a +market to buy it. + +And that saves a trip, saves +trouble, but it also-- + +so this was done at harvest +time, and it basically forced + +them to make a decision then. + +So you couldn't say, well, +maybe I'll buy it. + +Maybe I won't. + +I'll wait until when +I need it. + +It was kind of a all or nothing +decision, where they + +had to take a decision right +now when they had money. + +This was the first experiment. + +Then they follow it up a second +experiment where they + +took another set of people, +and then in the second + +experiment, they offered people +an additional choice. + +You can either choose +when you'll get-- + +we'll come to sell +you fertilizer. + +This was done before harvest, so +they didn't have any money + +at that time. + +So they said you can either tell +us, and we'll come right + +after harvest, or we'll +come when you plant. + +Just tell us what to do. + +So the first experiment, they +were not given the choice. + +They said you want it now, we'll +bring it to you free. + +You don't have to go collect. + +If not, that's it. + +Then you're on your own. + +Now, it's you can either +buy now or later. + +You're offered a choice. + +And the other thing that they +did was other people who were + +not given any offer like this, +when it came to the actual + +time of the planting, they came +to these people and said + +do you want to buy fertilizer. + +We'll bring it to you, and then +some people, they offered + +a 50% discount. + +So they actually said if +we give you a discount, + +will you buy it? + +So these were the treatments, so +think of the treatments as + +the first treatment, all or +nothing at harvest time, you + +want to buy fertilizer; second +treatment, before harvest, do + +you want to buy fertilizer at +harvest or later; third + +treatment, at planting time, do +you want to buy fertilizer + +from us if we deliver +it to you free. + +That's the experiment. + +Before we get into +the experiment, + +suppose people were-- + +what's the disadvantage +of saying that you + +can only buy it-- + +we'll offer it to you +now, but not later? + +What's the downside of that? + +Why did they go to the second +treatment, do you think, where + +they give you a choice +when to buy? + +What's the advantage of giving +you this choice? + +Yeah? + +AUDIENCE: [INAUDIBLE]? + +PROFESSOR: Right, exactly, I +mean, typically we think that + +buying things early +is a bad idea. + +Why? + +Because you're locking +up your money. + +I mean, fertilizer's not that +easy to sell, whereas if + +somebody got sick, you +had money, you'd + +be able to buy medicine. + +Now, instead you have +fertilizer. + +So why would you +lock up money? + +So in general, the standard +intuition would be that + +locking up money is a bad +idea, not a good idea. + +So in the first treatment, +they were + +forced to lock up money. + +The second one, they +give them a choice. + +So we take the first one, +basically, there was a 50%-- + +so about, as I said, 25% to 30% +of them use fertilizer. + +That went up by 11 to 14 +percentage points, so that's + +like a 46% to 63% increase +in fertilizer use. + +So you get more than 50%, more +than 50% increase in + +fertilizer use when you just +tell people, look, we'll bring + +it to you for free. + +Do you want it at +harvest time? + +This did not change-- + +so then what they looked at is +this season, of course, you + +getting it delivered to +you, so you buy it. + +It doesn't have any +persistent effect. + +You saw that it was +a good idea. + +Did you start saving money +or finding a way to + +buy ahead of time? + +The answer's no. + +People seem to be-- + +when you offer it to them for +free at harvest time, a + +substantial number +of them buy it. + +But if you said, look, last +year you did this, + +look, it was good. + +You got much more output. + +This time, why don't you +buy on your own? + +Just buy it at harvest time. + +We won't help you. + +You can do it on your own. + +Nobody does it. + +So it's not the case that +people learn from this + +experience to buy fertilizer +to use at harvest time. + +They go back to not using +it, basically. + +So when you give people a +choice, that's experiment two, + +you get bigger effects. + +Instead of getting 11 to 14 +percentage points, you get 18 + +percentage points. + +That's almost 75% increase in +fertilizer use, so if you give + +them a choice, then you get +more people taking it up. + +On the other hand, if you show +up at harvest time-- + +so this is not mainly an effect +of offering it to them, + +just bringing it to them. + +It's not because they're getting +free transportation. + +It's not because they don't have +to go buy it that they're + +doing it because if you came to +them at planting time and + +said do you want to buy it, +we'll get it to you free, that + +has no impact. + +If you bring it to people at +planting time free, then they + +don't buy it, so it's not the +case that you get the same + +effect by just delivering it +to them free at any time. + +You have to deliver +it to them free + +typically at planting time-- + +sorry, at harvest time. + +When they have money, you have +to deliver it to them free, + +then they buy it. + +If you bring it to them when +they are planting, and you + +offer free delivery, that +doesn't have the same impact. + +So it's not that whenever +you offer it to them + +free, they buy a lot. + +They only buy a lot if +you offer it free + +when they have money. + +The 50% discount does have a +significant effect, maybe not + +surprisingly. + +On the other hand, it's not +really smaller than just + +offering people to get free +delivery with no discount. + +No discount is better than +giving people a discount if + +you give them the discount +at the right time-- + +sorry, the free-- + +the delivery at the +right time. + +So if I go to you at harvest +time, and I say I won't give + +you a discount, when do you +want it, you get a bigger + +effect than if I tell you I'll +give you 50% discount, but + +that I offer that to you +only at planting time. + +So just those magnitudes are +what's worth looking at + +because you're getting +people-- + +it's not that people, even if +you offer them a 50% discount, + +you don't get as big an effect +as just finding the right time + +to make an offer without +a discount. + +Yeah? + +AUDIENCE: How do people get this +if it wasn't delivered? + +PROFESSOR: You just go to the +local town and you buy-- + +AUDIENCE: --drag it back +or pull it back-- + +PROFESSOR: Oh, you +bring it on a-- + +they have all these three-wheel +taxis and little + +trucks in Kenya. + +You put it in the back of +one, and you bring it. + +It's like-- + +AUDIENCE: [INAUDIBLE]? + +PROFESSOR: No, it's a small +cost, actually. + +That's the usual. + +Now, you notice that +there was this 18 + +percentage point increase. + +That came from a bunch of those +people said, look, it's + +free delivery, but +we just want it + +delivered at planting time. + +So some people behaved as if +they had no worries about + +having the money later, and the +other half said bring it + +to us now, so a bunch +of people said + +bring it to us now. + +The reason why this one gives +you a bigger effect than + +forcing people to buy early is +because a bunch of those + +people actually prefer +to get it late. + +So it's clear that the economics +we described before + +is working for some people, but +it's also striking that + +about half of those people +say, no, we want it now. + +We want to lock up our money. + +We want our money to +not be spendable. + +We want it in fertilizer now. + +So what's quite striking is +that people are willing to + +lock up their money, +even though it's-- + +So what could be going on? + +So here's a story that +seems to mostly work. + +So these people have money +at harvest time and want + +fertilizer, but somehow, they +don't manage to buy + +fertilizer. + +So the reason why the experiment +works is that these + +people basically say, look, +we will buy fertilizer. + +So what seems to be going on +is that, as we said, 98% of + +those people who had plots where +fertilizer was used said + +they wanted to buy it again. + +Only 37% actually did. + +So at harvest time, it seems +most people plan to use + +fertilizer, and then only +a small fraction of them + +actually managed to get there. + +So what seems to happen +is that they + +don't manage to implement. + +So they think that they're going +to buy fertilizer, but + +then somehow end up spending the +money before they get to + +the fertilizer. + +So one way to think about what +could be happening is that + +people say, look, today I really +want to buy fertilizer, + +but right now, I really like a +drink or I'd really like to + +have a barbecue. + +So they go to the market, they +buy something, and they say, + +look, it doesn't really matter +because tomorrow, + +I'm going to save. + +Today, let me have a barbecue, +but tomorrow, I'm definitely + +going to save. + +So they say that so it doesn't +really matter. + +It's going to be in three months +that we're going to + +plant, so even if I don't save +today, I'll save tomorrow. + +So sometimes, this is +represented by this formula. + +These kind of preferences are +sometimes [INAUDIBLE] + +by this formula. + +So the U function is the +utility you get or the + +pleasure you get out +of eating today or + +tomorrow or day after. + +Today is c0, tomorrow's c1, day +after is c2, the day after + +that is c3. + +Or we could think of months, +c0 this month, c1 is next + +month, et cetera. + +What's important is that U of +c1 is multiplied by two + +numbers, both less than 1. + +U of c2 is multiplied by +beta delta squared. + +If delta's less than 1, delta +squared is less than 1, but I + +didn't multiply by beta +squared delta squared. + +I multiplied by beta +delta squared. + +The day after that is multiplied +by beta delta + +cubed, so I didn't multiply +by beta cubed delta cubed. + +Why am I doing that? + +What's the point being made +by having that structure? + +This is sometimes called a +quasi hyperbolic model. + +Why did I put that +structure there? + +Yeah? + +AUDIENCE: Maybe like delta is +something that [INAUDIBLE] + +whereas beta is a variable that +probably won't happen. + +Like, [INAUDIBLE]. + +PROFESSOR: Well, specifically, +these are constant, so think + +of them as being numbers. + +Beta's like a number, like-- + +maybe delta is 0.9, and beta's +something like 0.6. + +That's the sort of numbers +people often throw + +around over a month. + +What does this preference +specifically say? + +Yeah? + +AUDIENCE: Seems like it's just +saying that if more importance + +is given to c0, and anything +in the future as a discount + +factor of beta. + +But the further into the future +you go, you go from + +delta to delta squared +so [INAUDIBLE]. + +PROFESSOR: Right, but +specifically what it's saying + +is that today versus tomorrow +is very different from + +tomorrow versus day +after or day after + +versus day after that. + +It's saying specifically that +when I offer you a choice + +between today and tomorrow, +you want it today, but you + +don't care as much about day +after versus day after that. + +So beta and delta both numbers +less than 1, then what this + +preference is exactly +saying is that I + +would take one today. + +I'll give up two tomorrow to +get one today, but when I + +compare tomorrow with day after, +I'm not going to take + +one tomorrow instead +of two day after. + +So people are very short-- + +they want things now, but they +don't really care about when + +they get it if they +don't get it now. + +Why is that an interesting +set of preferences? + +Well, if you believe those set +of preferences, then this + +behavior seems to start +to make sense. + +So what I really want +is I want tomorrow-- + +since I don't care about whether +I consume tomorrow or + +day after, I want tomorrow +to do the saving. + +Today, I don't want to save +because today is much more + +important to me than tomorrow. + +Tomorrow is not that much more +important than day after, so + +if I want some money for day +after, the best way to get + +there is by eating a lot today, +saving a lot tomorrow, + +and then ending up with +the money day after. + +I would rather do that than eat +little today and also a + +little tomorrow. + +I would rather save by binging +today and then waiting, and + +then implementing +saving tomorrow. + +The problem is that when +you get around to + +tomorrow, what happens? + +If your plan is I will save more +tomorrow, I'll eat more + +today, save more tomorrow, +what's the + +problem with that plan? + +AUDIENCE: Tomorrow +becomes today. + +PROFESSOR: Tomorrow +becomes today. + +Once tomorrow becomes today, you +start thinking, OK, well, + +I have the same preferences. + +c0 then becomes tomorrow's c0. + +I want to implement the +same plan tomorrow. + +I want to eat a lot tomorrow, +and get day after to do the + +savings, and you can +keep doing that. + +That's the problem. + +OK, so that's the idea. + +Now do people actually +behave in such a way? + +So here's an experiment. + +Ashraf, Karlan, and Win asked +1,700 subjects in the + +Philippines the following +questions. + +So they asked them, first, would +you prefer 200 pesos now + +or 250 pesos later? + +Some people said I'd prefer +250 later, in + +which case, they stopped. + +If they said that they would +prefer 200 now rather than 250 + +in a month, then they were +asked how about 300? + +If they said they'll even take +300, then they were asked how + +much would it take to stop you +from wanting 200 today? + +Somebody might say 400. + +I'll take 200 today +and 400 a month. + +So there are people who could +say 250 I'll take in a month. + +Some people say I'll take +300 in a month. + +Some people will say +name a number. + +So do you see how it goes? + +Then they are given a break. + +They went and wander around, +then came back, and 15 minutes + +later, they were asked the same +set of questions, but + +with one change, which is that +instead of asking them about + +today versus in a month, they +were asked in six months + +versus in seven months. + +Same thing, but notice +what we're doing is + +exactly this exercise. + +We are exactly trying to +pinpoint whether or not people + +have a different view of today +versus tomorrow versus one + +month later at any other +point of time. + +That's exactly the idea, that +am I someone who thinks that + +tomorrow is going to be-- + +do I think that tomorrow +it's going to be it + +really doesn't matter. + +I can cut back tomorrow, +but I really don't + +want to cut back today. + +So this is what they found. + +This is a complicated +table, but we can + +go through it slowly. + +So the way to think about +it is that the-- + +each square in a matrix is how +much money would you take + +today versus 200-- + +so how much money in the future +versus 200 today. + +Along the vertical dimension, +we're increasing the amount of + +money in a month from today. + +On the horizontal dimension, +we increasing the amount of + +money in a month from +six months. + +And those are the fraction of +people who make those choices. + +So some people are +just patient. + +Those people say, you offer +me 200 today, I'll + +take 250 in a month. + +You offer me 200 in six +months, I'll take + +250 in seven months. + +Some people say you offer +me 200 today, I + +take 250 in a month-- + +or more than 250, but less than +300 in a month, and they + +express the same preference +in the future as well. + +But then interesting people +are the people who seem to + +have different preferences, and +we see that there are both + +kinds of people. + +There are some people +who are-- + +So what is the dark squares? + +What are the dark squares +telling you? + +Who are those people? + +The really dark ones. + +What are their preferences? + +AUDIENCE: They'll take less +money, one month from now then + +require more money +in the future. + +PROFESSOR: The really daft, daft +ones are the ones who are + +saying I'll take less than 250 +for 200 in one month, but six + +months or seven months, it'll +take me more than 250 to + +compensate. + +So they seem to be the opposite +of the kind of people + +who you're talking about. + +They seem to be impatient +in the future but + +patient in the present. + +Yeah? + +AUDIENCE: All right, +I have a question. + +Could it be that it's not so +much about money today versus + +money tomorrow, and preferences +for consumption + +versus investment? + +So if you're waiting for the 250 +in a month, you're putting + +your income towards investment +as opposed to [INAUDIBLE] + +consumption. + +PROFESSOR: Sure. + +AUDIENCE: Does that +make sense? + +PROFESSOR: I mean, +it makes sense. + +It's just I don't understand +why that's different. + +It's the same thing. + +I'm going to get money +in the future. + +Investment is just a way to +get money in the future. + +I think it's the same thing. + +What's not visible, but I can +tell you, is that those three + +dark squares, which are people +who are patient now but + +impatient in the future-- + +that's about 15% of the +population seem to be patient + +now, impatient in the future. + +Now, the ones who are in the +kind of what I call hyperbolic + +squares, that's about 25% of +the population, they're + +impatient now, patient later. + +They are the people +who are impatient. + +They're saying I'll take 200 +now over 300 later, but-- + +or was it 250 later? + +But in a month, I'll reverse +that preferences. + +I'll take 200 in six +months rather than + +250 in seven months. + +Sorry, the other way. + +I'll take 250 in seven months, +but 200 in six months, and + +that's about 25% of +the population. + +And then there is another 17% +of the population who are in + +that other box, and they're +people for whom-- + +about half of those are actually +more patient now than + +they were in the future than +the other way around. + +So basically, what this +shows is that it's not + +everybody's like that. + +Some people are just +very impatient. + +Who are the very impatient +people? + +Which box would they be? + +AUDIENCE: [INAUDIBLE]. + +PROFESSOR: Those people, we-- + +You're right, they are +the people who are-- + +I guess they're the people who +are most impatient, but some + +of those people are more +impatient now. + +Some people are more impatient +in the future. + +Who are the most +patient people? + +Which box? + +AUDIENCE: Require 250 +now or later? + +PROFESSOR: Yeah, so the top +left-hand boxes were the most + +patient people. + +So basically, what this says +there's about a third of the + +population who are +very patient. + +Yeah? + +AUDIENCE: What were +the incomes of the + +people in this survey? + +Like is 250 a lot for them, +relative to 300 or-- + +PROFESSOR: No, these +are actually + +small amounts of money. + +Not very cvalued. + +These are not very big +amounts of money. + +AUDIENCE: But in terms of part +of their income, would that be + +significant or not? + +PROFESSOR: Significant per +billion, but really not. + +So the point that we want to +take away from this is that + +people seem to vary a lot. + +It's not that there's one kind +of people in the world. + +Some people are patient now and +impatient in the future. + +A lot more people are impatient +now and patient in + +the future. + +But there's a whole bunch of +people who are both impatient + +now and impatient in the future, +and a whole bunch of + +people who are patient now and +patient in the future. + +So there are all kinds +of different + +behaviors in this table. + +Yeah? + +AUDIENCE: Does this table change +for people in developed + +countries who are making +lots of money? + +PROFESSOR: So here's +another experiment. + +It's not here. + +Let's look at another one. + +This is actually interesting. + +I think I have it here. + +I'll show it to you. + +Actually not-- + +it's quite interesting. + +This one was done in the +US, and it's kind of + +interesting to see. + +[INAUDIBLE], OK, good. + +It is something funny. + +This is not going to get +recorded, but it's this-- + +yeah. + +So this is a very famous +experiment on the US. + +Exactly the same kind +of question, but + +now, people were asked-- + +so this is the median +response. + +So people were asked how much +money would you take in x + +months, where x is either three +months, one year, or + +three years, relative to +that much money today. + +OK, so this is in the US with +college students, and then + +these were Cornell students +if I remember right. + +So you can see, this +is the answer-- + +it's interesting. + +So if I offer you $15 today +versus $30 in three months, + +the median response-- + +many people were asked this +question, and this is the + +answer to the question, what's +the median response. + +So if you take half +the people-- + +so for example, for $15, half +the people said I'll take less + +than $30, half the people said +I'll take more than $30, so + +the median response was $30. + +So you can see that, basically, +the US in three + +months, the trade off +is basically people + +want twice the money. + +That's a yearly discount +factor of 277%. + +For one year, they say $60. + +For three years, +they say $100. + +Now, the point is that that +number is getting, relatively, + +you're getting more patient as +you look into the future. + +So it's today versus the future +always, but as I may + +force you to look further into +the future, you become + +actually more patient. + +And that sort of phenomenon I +was alluding to, which is that + +as people really want it today, +but the difference + +between tomorrow and in +one year later is + +not that much more. + +AUDIENCE: So the amount +increase, right? + +It's not [INAUDIBLE] + +more patient just because you +are talking about $3,000 + +versus $15. + +Then you say [INAUDIBLE]. + +PROFESSOR: Yeah, so that's +exactly right. + +That's to make the other +point, that as amounts + +increase, people look like +they're more patient. + +So if this was a lot of money-- +so in the US, they're + +going to look actually more +impatient than in the + +Philippines. + +The Philippines, they were +looking much more patient + +because these were actually big +amounts of money in the + +Philippines. + +In the US, for those +amounts of money, + +they look more impatient. + +So it's when the amounts of +money are bigger, people seem + +to look more patient. + +That's the bottom +line of that. + +The bottom of that says that +once you go to $3,000, people + +really don't want +twice as much. + +They'll take much less than +twice as much to wait three + +months, so people get much more +patient as you increase + +the amount of money. + +I think that's a very kind +of interesting fact. + +I need to go back to where +I was, but this is a-- + +so that's kind of the answer to +your question, is that this + +is actually relatively-- + +people are actually-- no, +this is the wrong-- + +I need to go back to the PDF. + +So actually, they are relatively +patient here + +because these are amounts of +money that are relatively + +large for them. + +If you make the amount of money +smaller, people become + +less patient, not +more patient. + +So in the US, with these +choices, they look more + +impatient actually, not +less impatient. + +OK, so the question is can this +is really explain the + +fertilizer puzzle? + +So we can see that there are +people, about a quarter of the + +population, do behave +in this funny way. + +They want it now, and they think +in the future they're + +going to be very patient, +so they want to + +postpone their savings. + +They want to say I will consume +now and save later. + +That's a kind of a natural +instinct for about a quarter + +of the population. + +The problem is that this +requires people + +to be pretty naive. + +What do I mean by naive? + +I mean they need to actually not +realize that this is what + +they're doing because otherwise +they should be able + +to say, look, but I'll do that +tomorrow as well, and day + +after and the day after that, so +I'll never buy fertilizer. + +I want to buy fertilizer. + +So if you were sophisticated +and, you fully understood what + +you were doing, what +would you do? + +Yeah? + +AUDIENCE: You force yourself +to save [INAUDIBLE]. + +PROFESSOR: You'll buy now. + +You just buy now. + +You know that you can +never really-- + +Yeah, or you save now, whatever +you need to do. + +You know that you'll never win +the game by postponing because + +you know tomorrow you'll +have the same problem. + +So basically, if you're +sophisticated, + +you would buy now. + +So you never want to do it, so +you really need people to be + +pretty naive to be able to-- + +In other words, sophisticated +people should not react to + +this program. + +They would buy in any case. + +The only advantage this program +offers is that they're + +getting free delivery, but free +delivery, as we saw, is + +not worth that much. + +When you give people just free +delivery, that doesn't have a + +big effect. + +So in other words, if these guys +are really sophisticated, + +they shouldn't need this program +to get them to buy + +fertilizer. + +They would buy it in any case +because they'll realize that + +this is what's going on and +say, look, if I can try to + +fool myself and say I'm going +to buy it tomorrow, but I'm + +not going to buy it tomorrow. + +I'm always going to +do the same thing. + +Yeah? + +AUDIENCE: Didn't they say that +the fertilizer wasn't + +available [INAUDIBLE] + +back to the city to check +it, so that's why they + +[INAUDIBLE]? + +PROFESSOR: I'm sure that's also +true, but just take this + +particular experiment. + +I'm sure there are other costs, +like there is some + +transportation costs of finding +fertilizer, et cetera, + +but it's hard to imagine that's +the only problem. + +However, here's a problem with +saying that they are + +sophisticated. + +Suppose people were +sophisticated, then they + +wouldn't want the fertilizer-- + +the program would not have an +effect because, basically, + +they would buy it in any case. + +Now, suppose they're not +sophisticated, so they don't + +understand they do this. + +Suppose they come and tell you +do you want to buy now or in + +the future? + +What would you say? + +You all would say in the future +because why would + +[INAUDIBLE]? + +I don't realize I'm going to +do this, so then I have no + +reason to say lock +up my money. + +I should always ask to spend +it in the future. + +You cannot have them being +completely fully + +sophisticated, in which case the +program would not have an + +effect, because they're +sophisticated. + +They don't need the program. + +They'll buy in any case. + +But if you assume that they was +not sophisticated at all, + +then they would say, +look, bring it + +back at planting time. + +I'll buy it then. + +Why would I lockup my money? + +Because I don't understand +that I have this problem. + +So these people must be +halfway between being + +sophisticated and not +being sophisticated. + +They cannot be either +fully sophisticated. + +If they were fully +sophisticated, they would not + +need this program. + +If they were fully +unsophisticated, they would + +not respond to when you offer +them and ask them do you want + +to buy it now or later, they +would all say later, and half + +of them say they want it now +even though they don't need + +the fertilizer now. + +So some of those people must +realize that later, they're + +going to not have the money, +so somehow there is some + +combination of sophistication +and naivete that's driving + +this behavior. + +So one way to look at this +question of how sophisticated + +is go back to that experiment +that we were talking about, + +the Ashraf, Karlan, and Yin. + +What they do is they offer their +subjects a lock-box. + +A lock-box is just a box where +the key is usually kept with + +someone else, so you don't +have access to the key. + +You can put money into it. + +It's just a money box. + +And they were told that +you can set you goal. + +Your goal can be either a date, +so I'll break the box, + +I'll open the box +at Christmas. + +Or it could be an +amount of money. + +I'll open the box once +I have $200 in it. + +So if you look at what people +say, most people want it on a + +date, so a huge fraction say +I want it on Christmas, my + +wife's birthday, my husband's +birthday, my son's birthday, + +my child's graduation, +something like that. + +Then some people have an +amount based goal. + +They say that I need it for +buying a house, so I need this + +much money. + +But most people seemed to +set time-based goals. + +Now, out of 1,7000 people, +only 200 people + +wanted these boxes. + +So not everybody wanted it. + +In fact, only one out of eight, +roughly, wanted one of + +these boxes. + +But among those who did, there's +a massive effect of + +being hyperbolic. + +Hyperbolic are those people who +are patient in the future + +but impatient now. + +Those are the people who really +wanted the lock-boxes, + +so that's what you'd expect. + +You'd expect that somebody who +is fundamentally patient, but + +is impatient right now, is the +one who wants a lock-box + +because they do see the +value of saving. + +They're patient fundamentally, +but they're impatient right + +now in the moment. + +Those are the people who would +want a lock-box, and that's + +exactly what you find. + +You find that the people who +want the lock-box tend to be + +people who are patient in +general, in the future are + +patient, but are less +patient right now. + +They want the lock-box to kind +of bind their hands. + +So they seem to know that +they're hyperbolic, so a lot + +of these people seem to know +they're hyperbolic. + +They seem to realize that they +have this problem, so they're + +not unsophisticated. + +They seem to be relatively aware +of their-- they're not, + +at least, totally +unsophisticated. + +They seem to have some +awareness of their + +self-control problem. + +The other striking thing is +only women are effected. + +Men don't seem to understand +they have this problem, even + +though they do, actually. + +So women seem to understand +they have a problem. + +Men also have the same problem, +but they don't seem + +to understand it. + +Now, here's another experiment, +last experiment we + +will talk about, which gives a +different take to this men + +versus women question. + +We've been talking a lot about +this kind of hyperbolic view, + +which says that I'm worried that +I won't be able to save. + +An alternative view of why +people don't save is they feel + +like I want to save, but I +know that I can't because + +somebody else will come and +take the money away. + +My husband will spend it, or my +brother will come and beg + +me money, and I'll have to give +it to him or something. + +So one other reason for not +saving, which is related, and + +one reason why women might want +a lock-box more might not + +be because just that +they're hyperbolic. + +They might also worry about the +fact that their husbands + +will just take away the money, +and that might explain their + +demand for lock-boxes, that they +want to keep the money + +away from their husband and say +that we can't get at the + +money right now. + +So this is an experiment +in a bank. + +This one was done by Simone +Schaner, who was a + +PhD Student at MIT. + +So this is a bank, and +basically, she invited a bunch + +of married couples to the bank +and said do you want to open + +an account. + +And the accounts she offered +had came in three types. + +I mean, everybody was offered +one joint account for two + +spouses, one wife's account, +and one husband's account. + +The reason why they did that, +she was trying to get at this + +idea that maybe if I have a +joint account with my husband, + +that's not very good because +he can take out the money. + +If I want to have an account, +I want full control of it. + +So what she's interested in is +this question, are people + +sufficiently aware of this +problem that they're willing + +to give up a high return +account to + +have their own account? + +So the design of the experiment +is one where, + +sometimes, randomly, the joint +account has the highest + +interest rate, and your own +account has a very low + +interest rate. + +And what she's interested in is +whether you would give up + +getting a high interest +rate account to + +get your own account. + +So for the whole family, it +would be better to get a joint + +account in terms of returns. + +So the returns can vary between +0% to 10%, so you + +could be getting 10% on the +account instead of zero, but + +you might choose zero because +you don't want your wife or + +husband to get at it. + +So I'll skip this. + +This just explain the point. + +The point is that people got +different accounts offered, so + +some people were offered a +joint account with the + +interest rate zero, a man's +account with interest rate + +zero, but a joint account +with interest rate two. + +So this is sort of just to +understand the experiment, you + +might be someone who gets the +joint account interest rates + +could be 10, but the man's +account interest rate could be + +zero, and the woman's account +interest rate could be two. + +So what's in the squares are +the excess interest rate on + +the account you're choosing, so +maybe you choose an account + +which gives you 4%. + +You could have gotten the best +account you could have got + +would have interest +rate of 10. + +Your excess interest rate is +negative in that case. + +You are getting a -6% +on the interest. + +So the question here, the reason +why this experiment is + +interesting, you're trying to +figure out do people give up + +getting lots of extra money +to make sure that somebody + +doesn't have access +to their account. + +So first thing she did +was to figure out-- + +she'll administer +these questions + +where they ask them-- + +it's kind of like the questions +we were asking. + +How much money would you give +up today for 290 Kenyan + +shillings tomorrow? + +So these are questions basically +aimed to measure how + +impatient people. + +Would you take 20 today or 200 +tomorrow, and if you say 20 + +today, you're very impatient, +obviously. + +So that's the kind of question +she was asking. + +So what she did, by using that, +what she figured out was + +who are the couples who +are well matched. + +So if I'm impatient and my wife +is impatient, that's no + +problem because neither +of us want to save. + +So I don't have to tie my +husband's hands or my wife's + +hands because I have the same +preferences as she does, and + +therefore, if she wants to +spend, I also want to spend. + +Then there are couple which are +both parties are patient, + +so if one wants to save, the +other wants to save. + +And then there are people +who were given-- + +the couples which +are ill matched. + +Ill matched couples are where +one says I want to save now, + +the other says I want +to spend now. + +So they're ill matched +couples. + +Now, it's the ill matched +couples that are going to + +choose accounts that +have low returns. + +If you're well matched, it +really doesn't matter who's + +name the account is in because +we have the same objectives. + +We both want to spend now. + +We both want to spend +in the future. + +Whatever we want to do, +we both want to do. + +But if one of the spouses is +patient, and the other's + +impatient, you have a problem. + +Now, it turns out, she went +with the hypothesis that + +she'll find that only the +men are impatient. + +Turns out it was about 50/50, +about men and women are + +equally likely to be less +patient than their spouse. + +But a lot of these households +were ill matched, so a lot of + +the households had one spouse +who was very patient and the + +other spouse who was +very impatient. + +That's a setting where you'd +imagine going back to the + +issue we were raising, as we +said, maybe people don't save + +because they feel that +they can't save. + +If they try to save, the spouse +will just spend it. + +So if one of the spouses is +patient, but the other's + +impatient, the impatient +spouse kind of has an + +advantage because once the +money's spent, it's gone. + +The patient spouse will keep +guarding the money, but the + +impatient spouse, all she has +to do is to spend it. + +Once it's spent, it's gone, so +in a sense, the impatience + +spouse always has +an advantage. + +So you're always fighting +against the impatience spouse. + +The patient spouse is always +trying to save it and can't do + +much about it once the +money's spent. + +But as a patient spouse +is always-- + +if she's saved it through today, +she has to save it + +through tomorrow. + +In some sense, it's kind of +an asymmetric problem. + +So what she's looking for is +what happens to these ill + +matched couples. + +So this is sort of just to give +a sense of how many are + +ill matched. + +Yeah, Melissa? + +AUDIENCE: [INAUDIBLE]? + +PROFESSOR: We'll be done +in two minutes. + +So this is a graph of +ill matched couples. + +A lot of these are at zero. + +You can see zero means you have +the same discount factor. + +You're equally patient. + +But you can see that there are +people who are difference of + +-0.5, so that means +that I want it-- + +my discount factor is maybe +0.9, and my spouse is 0.4. + +And look, it's basically +symmetrical. + +Men and women are +not different. + +It's just one of the +spouses is more + +impatient than the other. + +And then what she looks at-- + +I'll skip these and show +you the picture. + +So on the horizontal axis +is excess interest rate. + +How much are you giving up? + +When the wife's account has, +let's say, the highest + +interest rate over the +other account-- + +what fraction of the people +use the account more? + +And you can see that basically, +for well matched + +couples, the shared saving in +that account is clearly + +increasing with interest rate. + +If the interest rate +is higher, you save + +more in that account. + +For ill matched couples, they +see no relationship. + +You don't save more because the +account is more rewarding. + +Why? + +Because it doesn't matter if +it's more rewarding or not. + +You just don't want that on +the other guy to have that + +access to that account. + +So ill matched couples don't +react to the interest rate. + +Their priority is +something else. + +They want their own account. + +Doesn't matter whether that's +a low interest account. + +The well matched couples, you +see this, and you can see the + +same thing for the +joint accounts. + +The joint accounts, again, it's +the same question, excess + +interest rate, share saving. + +The well matched couples, as the +interest rate goes up, you + +save more in that account. + +In the badly matched couples, +it doesn't matter. + +Interest rate doesn't matter. + +If you're badly matched, you +choose the one that you will + +keep the other guy out. + +You're not the one that has +the highest interest rate. \ No newline at end of file diff --git a/rhNKncraJMk.txt b/rhNKncraJMk.txt new file mode 100644 index 0000000000000000000000000000000000000000..ed195456098d13a9007f8036dc135399d6e51e72 --- /dev/null +++ b/rhNKncraJMk.txt @@ -0,0 +1,1427 @@ +align:start position:0% + +Hi, I'm Ben. Today we are going to do an + + align:start position:0% +Hi, I'm Ben. Today we are going to do an + + + align:start position:0% +Hi, I'm Ben. Today we are going to do an +LU decomposition problem. Here's the + + align:start position:0% +LU decomposition problem. Here's the + + + align:start position:0% +LU decomposition problem. Here's the +problem right here. Find the LU + + align:start position:0% +problem right here. Find the LU + + + align:start position:0% +problem right here. Find the LU +decomposition of this matrix A. Now + + align:start position:0% +decomposition of this matrix A. Now + + + align:start position:0% +decomposition of this matrix A. Now +notice that this matrix A has variables + + align:start position:0% +notice that this matrix A has variables + + + align:start position:0% +notice that this matrix A has variables +as well as numbers. So + + align:start position:0% +as well as numbers. So + + + align:start position:0% +as well as numbers. So +uh the sentence ends when it exists. And + + align:start position:0% +uh the sentence ends when it exists. And + + + align:start position:0% +uh the sentence ends when it exists. And +the second part of the question asks you + + align:start position:0% +the second part of the question asks you + + + align:start position:0% +the second part of the question asks you +for which real numbers A and B does the + + align:start position:0% +for which real numbers A and B does the + + + align:start position:0% +for which real numbers A and B does the +LU decomposition of this matrix actually + + align:start position:0% +LU decomposition of this matrix actually + + + align:start position:0% +LU decomposition of this matrix actually +exist. Now uh you can hit pause now and + + align:start position:0% +exist. Now uh you can hit pause now and + + + align:start position:0% +exist. Now uh you can hit pause now and +I'll get you uh give you a few seconds. + + align:start position:0% +I'll get you uh give you a few seconds. + + + align:start position:0% +I'll get you uh give you a few seconds. +You can try to solve this on your own + + align:start position:0% +You can try to solve this on your own + + + align:start position:0% +You can try to solve this on your own +and then we'll be back and we can do it + + align:start position:0% +and then we'll be back and we can do it + + + align:start position:0% +and then we'll be back and we can do it +together. + + align:start position:0% + + + + align:start position:0% + +And we're + + align:start position:0% +And we're + + + align:start position:0% +And we're +back. Now, what do you have to remember + + align:start position:0% +back. Now, what do you have to remember + + + align:start position:0% +back. Now, what do you have to remember +when doing an LU decomposition + + align:start position:0% +when doing an LU decomposition + + + align:start position:0% +when doing an LU decomposition +problem? Well, it's we do elimination in + + align:start position:0% +problem? Well, it's we do elimination in + + + align:start position:0% +problem? Well, it's we do elimination in +the same way that we + + align:start position:0% +the same way that we + + + align:start position:0% +the same way that we +uh um did before in order to find U. But + + align:start position:0% +uh um did before in order to find U. But + + + align:start position:0% +uh um did before in order to find U. But +with this question, we need to find L as + + align:start position:0% +with this question, we need to find L as + + + align:start position:0% +with this question, we need to find L as +well. So, we need to do elimination, but + + align:start position:0% +well. So, we need to do elimination, but + + + align:start position:0% +well. So, we need to do elimination, but +we also need to keep track of the + + align:start position:0% +we also need to keep track of the + + + align:start position:0% +we also need to keep track of the +elimination matrices along the way. + + align:start position:0% +elimination matrices along the way. + + + align:start position:0% +elimination matrices along the way. +Good. So, let's let's do that. So, let + + align:start position:0% +Good. So, let's let's do that. So, let + + + align:start position:0% +Good. So, let's let's do that. So, let +me put my matrix up + + align:start position:0% + + + + align:start position:0% + +here. Okay. And we want to do + + align:start position:0% +here. Okay. And we want to do + + + align:start position:0% +here. Okay. And we want to do +elimination. So, which entry do we + + align:start position:0% +elimination. So, which entry do we + + + align:start position:0% +elimination. So, which entry do we +eliminate + + align:start position:0% +eliminate + + + align:start position:0% +eliminate +first? That's right. It's it's this 21 + + align:start position:0% +first? That's right. It's it's this 21 + + + align:start position:0% +first? That's right. It's it's this 21 +entry. + + align:start position:0% +entry. + + + align:start position:0% +entry. +We so we replace the second row by the + + align:start position:0% +We so we replace the second row by the + + + align:start position:0% +We so we replace the second row by the +second row minus a times the the first + + align:start position:0% +second row minus a times the the first + + + align:start position:0% +second row minus a times the the first +row and we get + + align:start position:0% + + + + align:start position:0% + +this. Okay, but we're not just doing + + align:start position:0% +this. Okay, but we're not just doing + + + align:start position:0% +this. Okay, but we're not just doing +elimination. We're finding an LU + + align:start position:0% +elimination. We're finding an LU + + + align:start position:0% +elimination. We're finding an LU +decomposition. So, we need to keep track + + align:start position:0% +decomposition. So, we need to keep track + + + align:start position:0% +decomposition. So, we need to keep track +of the matrix that I multiplied the uh + + align:start position:0% +of the matrix that I multiplied the uh + + + align:start position:0% +of the matrix that I multiplied the uh +elimination matrix that I multiplied + + align:start position:0% +elimination matrix that I multiplied + + + align:start position:0% +elimination matrix that I multiplied +this matrix A by on the left to get this + + align:start position:0% +this matrix A by on the left to get this + + + align:start position:0% +this matrix A by on the left to get this +matrix. So, what is that? That's this + + align:start position:0% +matrix. So, what is that? That's this + + + align:start position:0% +matrix. So, what is that? That's this +E21. Since I eliminated the 21 entry, + + align:start position:0% +E21. Since I eliminated the 21 entry, + + + align:start position:0% +E21. Since I eliminated the 21 entry, +I'll call it + + align:start position:0% +I'll call it + + + align:start position:0% +I'll call it +E21. And it's this + + align:start position:0% +E21. And it's this + + + align:start position:0% +E21. And it's this +matrix. Why is it this matrix? Well, + + align:start position:0% +matrix. Why is it this matrix? Well, + + + align:start position:0% +matrix. Why is it this matrix? Well, +remember how multiplication on the left + + align:start position:0% +remember how multiplication on the left + + + align:start position:0% +remember how multiplication on the left +works? I replace the first row by just + + align:start position:0% +works? I replace the first row by just + + + align:start position:0% +works? I replace the first row by just +the first row. I replace the second row + + align:start position:0% +the first row. I replace the second row + + + align:start position:0% +the first row. I replace the second row +by the second row minus a times the f + + align:start position:0% +by the second row minus a times the f + + + align:start position:0% +by the second row minus a times the f +the first row. So you can just read off + + align:start position:0% +the first row. So you can just read off + + + align:start position:0% +the first row. So you can just read off +from these rows which operations I did. + + align:start position:0% +from these rows which operations I did. + + + align:start position:0% +from these rows which operations I did. +Good. Now which entry should we + + align:start position:0% +Good. Now which entry should we + + + align:start position:0% +Good. Now which entry should we +eliminate next? We need to eliminate + + align:start position:0% +eliminate next? We need to eliminate + + + align:start position:0% +eliminate next? We need to eliminate +this B. So we + + align:start position:0% +this B. So we + + + align:start position:0% +this B. So we +will replace the third row by the third + + align:start position:0% +will replace the third row by the third + + + align:start position:0% +will replace the third row by the third +row minus B * the first + + align:start position:0% + + + + align:start position:0% + +row. And which elimination matrix did we + + align:start position:0% +row. And which elimination matrix did we + + + align:start position:0% +row. And which elimination matrix did we +use? + + align:start position:0% + + + + align:start position:0% + +Well, note we replace the third row by + + align:start position:0% +Well, note we replace the third row by + + + align:start position:0% +Well, note we replace the third row by +the third row minus B times the first + + align:start position:0% +the third row minus B times the first + + + align:start position:0% +the third row minus B times the first +row. That's exactly what you should read + + align:start position:0% +row. That's exactly what you should read + + + align:start position:0% +row. That's exactly what you should read +off this elimination + + align:start position:0% +off this elimination + + + align:start position:0% +off this elimination +matrix. Good. Now, we only have one one + + align:start position:0% +matrix. Good. Now, we only have one one + + + align:start position:0% +matrix. Good. Now, we only have one one +step left, right? We only need to + + align:start position:0% +step left, right? We only need to + + + align:start position:0% +step left, right? We only need to +eliminate one last entry. But this one's + + align:start position:0% +eliminate one last entry. But this one's + + + align:start position:0% +eliminate one last entry. But this one's +a little tricky. So, let's be + + align:start position:0% +a little tricky. So, let's be + + + align:start position:0% +a little tricky. So, let's be +careful. In order to eliminate this uh + + align:start position:0% +careful. In order to eliminate this uh + + + align:start position:0% +careful. In order to eliminate this uh +B, we need A to be a pivot. In + + align:start position:0% +B, we need A to be a pivot. In + + + align:start position:0% +B, we need A to be a pivot. In +particular, we need a to be non zero. If + + align:start position:0% +particular, we need a to be non zero. If + + + align:start position:0% +particular, we need a to be non zero. If +if a were zero here, then we would have + + align:start position:0% +if a were zero here, then we would have + + + align:start position:0% +if a were zero here, then we would have +to do a row exchange. And that's no + + align:start position:0% +to do a row exchange. And that's no + + + align:start position:0% +to do a row exchange. And that's no +good. You can't find an LU decomposition + + align:start position:0% +good. You can't find an LU decomposition + + + align:start position:0% +good. You can't find an LU decomposition +if you have to do a row exchange in + + align:start position:0% +if you have to do a row exchange in + + + align:start position:0% +if you have to do a row exchange in +elimination. So, we need to + + align:start position:0% +elimination. So, we need to + + + align:start position:0% +elimination. So, we need to +assume that a is non + + align:start position:0% +assume that a is non + + + align:start position:0% +assume that a is non +zero in order to keep + + align:start position:0% +zero in order to keep + + + align:start position:0% +zero in order to keep +going. Okay. So, let's just assume there + + align:start position:0% +going. Okay. So, let's just assume there + + + align:start position:0% +going. Okay. So, let's just assume there +that a is non zero. + + align:start position:0% +that a is non zero. + + + align:start position:0% +that a is non zero. +Now what do we do? Well, we can replace + + align:start position:0% +Now what do we do? Well, we can replace + + + align:start position:0% +Now what do we do? Well, we can replace +the third row by the third row minus b / + + align:start position:0% +the third row by the third row minus b / + + + align:start position:0% +the third row by the third row minus b / +a * the the uh second + + align:start position:0% +a * the the uh second + + + align:start position:0% +a * the the uh second +row. + + align:start position:0% +row. + + + align:start position:0% +row. +And we just get this + + align:start position:0% +And we just get this + + + align:start position:0% +And we just get this +uh a minus b. Good. And let's write down + + align:start position:0% +uh a minus b. Good. And let's write down + + + align:start position:0% +uh a minus b. Good. And let's write down +our elimination + + align:start position:0% +our elimination + + + align:start position:0% +our elimination +matrix e uh + + align:start position:0% +matrix e uh + + + align:start position:0% +matrix e uh +32 now. + + align:start position:0% + + + + align:start position:0% + +There's our elimination matrix. We + + align:start position:0% +There's our elimination matrix. We + + + align:start position:0% +There's our elimination matrix. We +replace the third row by the third row + + align:start position:0% +replace the third row by the third row + + + align:start position:0% +replace the third row by the third row +minus B / A * the second row. + + align:start position:0% + + + + align:start position:0% + +Good. Good. So, we found our U matrix. + + align:start position:0% +Good. Good. So, we found our U matrix. + + + align:start position:0% +Good. Good. So, we found our U matrix. +That's what elimination does. It gives + + align:start position:0% +That's what elimination does. It gives + + + align:start position:0% +That's what elimination does. It gives +us our U matrix. So, let me write it up + + align:start position:0% +us our U matrix. So, let me write it up + + + align:start position:0% +us our U matrix. So, let me write it up +here. + + align:start position:0% + + + + align:start position:0% + +1 0 + + align:start position:0% +1 0 + + + align:start position:0% +1 0 +1 0 a + + align:start position:0% +1 0 a + + + align:start position:0% +1 0 a +0 0 uh a minus + + align:start position:0% + + + + align:start position:0% + +b. Good. Okay. Now we have to find our L + + align:start position:0% +b. Good. Okay. Now we have to find our L + + + align:start position:0% +b. Good. Okay. Now we have to find our L +matrix and we need to use these + + align:start position:0% +matrix and we need to use these + + + align:start position:0% +matrix and we need to use these +elimination matrices that we've been + + align:start position:0% +elimination matrices that we've been + + + align:start position:0% +elimination matrices that we've been +recording along the way in order to do + + align:start position:0% +recording along the way in order to do + + + align:start position:0% +recording along the way in order to do +that. Okay. So remember that we started + + align:start position:0% +that. Okay. So remember that we started + + + align:start position:0% +that. Okay. So remember that we started +with + + align:start position:0% +with + + + align:start position:0% +with +A and we got U. And how did we do that? + + align:start position:0% +A and we got U. And how did we do that? + + + align:start position:0% +A and we got U. And how did we do that? +Well, we multiplied on the left by all + + align:start position:0% +Well, we multiplied on the left by all + + + align:start position:0% +Well, we multiplied on the left by all +of these elimination matrices. + + align:start position:0% +of these elimination matrices. + + + align:start position:0% +of these elimination matrices. +E21, + + align:start position:0% +E21, + + + align:start position:0% +E21, +E31, and + + align:start position:0% +E31, and + + + align:start position:0% +E31, and +E32. Sorry if that's scrunching together + + align:start position:0% +E32. Sorry if that's scrunching together + + + align:start position:0% +E32. Sorry if that's scrunching together +there. Now, if we move these elimination + + align:start position:0% +there. Now, if we move these elimination + + + align:start position:0% +there. Now, if we move these elimination +matrices to the other side, then we'll + + align:start position:0% +matrices to the other side, then we'll + + + align:start position:0% +matrices to the other side, then we'll +get L + + align:start position:0% +get L + + + align:start position:0% +get L +So what do we have? We have a + + align:start position:0% +So what do we have? We have a + + + align:start position:0% +So what do we have? We have a +equ= e21 inverse e31 + + align:start position:0% +equ= e21 inverse e31 + + + align:start position:0% +equ= e21 inverse e31 +inverse e 32 inverse time u and this is + + align:start position:0% +inverse e 32 inverse time u and this is + + + align:start position:0% +inverse e 32 inverse time u and this is +our l this product of these three + + align:start position:0% +our l this product of these three + + + align:start position:0% +our l this product of these three +matrices. Good. So let's compute it + + align:start position:0% +matrices. Good. So let's compute it + + + align:start position:0% +matrices. Good. So let's compute it +now. Right? So L is the product of three + + align:start position:0% +now. Right? So L is the product of three + + + align:start position:0% +now. Right? So L is the product of three +matrices. I need to get them by going + + align:start position:0% +matrices. I need to get them by going + + + align:start position:0% +matrices. I need to get them by going +back and looking at these three + + align:start position:0% +back and looking at these three + + + align:start position:0% +back and looking at these three +elimination matrices and taking their + + align:start position:0% +elimination matrices and taking their + + + align:start position:0% +elimination matrices and taking their +inverses. Well, the nice thing about + + align:start position:0% +inverses. Well, the nice thing about + + + align:start position:0% +inverses. Well, the nice thing about +taking an inverse of this of an + + align:start position:0% +taking an inverse of this of an + + + align:start position:0% +taking an inverse of this of an +elementary matrix like this is we just + + align:start position:0% +elementary matrix like this is we just + + + align:start position:0% +elementary matrix like this is we just +make a minus a plus or a plus a minus. + + align:start position:0% +make a minus a plus or a plus a minus. + + + align:start position:0% +make a minus a plus or a plus a minus. +So that's + + align:start position:0% +So that's + + + align:start position:0% +So that's +easy + + align:start position:0% +easy + + + align:start position:0% +easy +enough. We just change the off diagonal + + align:start position:0% +enough. We just change the off diagonal + + + align:start position:0% +enough. We just change the off diagonal +entries. We just change their signs. + + align:start position:0% + + + + align:start position:0% + +You can check that that uh does what we + + align:start position:0% +You can check that that uh does what we + + + align:start position:0% +You can check that that uh does what we +wanted it + + align:start position:0% +wanted it + + + align:start position:0% +wanted it +to. Gives us the + + align:start position:0% +to. Gives us the + + + align:start position:0% +to. Gives us the +inverse. Good. And the last comment is + + align:start position:0% +inverse. Good. And the last comment is + + + align:start position:0% +inverse. Good. And the last comment is +that multiplying these three matrices is + + align:start position:0% +that multiplying these three matrices is + + + align:start position:0% +that multiplying these three matrices is +really easy in this order. Turns out it + + align:start position:0% +really easy in this order. Turns out it + + + align:start position:0% +really easy in this order. Turns out it +just all you do is you just plop these + + align:start position:0% +just all you do is you just plop these + + + align:start position:0% +just all you do is you just plop these +entries right + + align:start position:0% + + + + align:start position:0% + +in one. One. Good. So this is our L + + align:start position:0% + + + + align:start position:0% + +matrix. Good. So now we have our U + + align:start position:0% +matrix. Good. So now we have our U + + + align:start position:0% +matrix. Good. So now we have our U +matrix and our L matrix. And we're done + + align:start position:0% +matrix and our L matrix. And we're done + + + align:start position:0% +matrix and our L matrix. And we're done +with the first part of the question. The + + align:start position:0% +with the first part of the question. The + + + align:start position:0% +with the first part of the question. The +second part asks us for which real + + align:start position:0% +second part asks us for which real + + + align:start position:0% +second part asks us for which real +numbers A and B does this decomposition + + align:start position:0% +numbers A and B does this decomposition + + + align:start position:0% +numbers A and B does this decomposition +exist. Now let's go back and remember + + align:start position:0% +exist. Now let's go back and remember + + + align:start position:0% +exist. Now let's go back and remember +that at one point we had to assume that + + align:start position:0% +that at one point we had to assume that + + + align:start position:0% +that at one point we had to assume that +A was non zero. That was the only + + align:start position:0% +A was non zero. That was the only + + + align:start position:0% +A was non zero. That was the only +assumption we had to make to get this + + align:start position:0% +assumption we had to make to get this + + + align:start position:0% +assumption we had to make to get this +decomposition. + + align:start position:0% +decomposition. + + + align:start position:0% +decomposition. +So it + + align:start position:0% +So it + + + align:start position:0% +So it +exists it being this decomposition when + + align:start position:0% +exists it being this decomposition when + + + align:start position:0% +exists it being this decomposition when +a is non + + align:start position:0% +a is non + + + align:start position:0% +a is non +zero and that's the answer to the second + + align:start position:0% +zero and that's the answer to the second + + + align:start position:0% +zero and that's the answer to the second +part. Good. So we have our LU + + align:start position:0% +part. Good. So we have our LU + + + align:start position:0% +part. Good. So we have our LU +decomposition and we we know when it + + align:start position:0% +decomposition and we we know when it + + + align:start position:0% +decomposition and we we know when it +exists. Before I end, two + + align:start position:0% +exists. Before I end, two + + + align:start position:0% +exists. Before I end, two +comments. + + align:start position:0% +comments. + + + align:start position:0% +comments. +First, always check your work. always go + + align:start position:0% +First, always check your work. always go + + + align:start position:0% +First, always check your work. always go +back and multiply L times U and make + + align:start position:0% +back and multiply L times U and make + + + align:start position:0% +back and multiply L times U and make +sure it's A because it's easy to screw + + align:start position:0% +sure it's A because it's easy to screw + + + align:start position:0% +sure it's A because it's easy to screw +up the elimination process and uh it's + + align:start position:0% +up the elimination process and uh it's + + + align:start position:0% +up the elimination process and uh it's +easy to check your work. So you should + + align:start position:0% +easy to check your work. So you should + + + align:start position:0% +easy to check your work. So you should +go back and make sure things are uh as + + align:start position:0% +go back and make sure things are uh as + + + align:start position:0% +go back and make sure things are uh as +they should be. Second comment is that + + align:start position:0% +they should be. Second comment is that + + + align:start position:0% +they should be. Second comment is that +you might be worried when you do this + + align:start position:0% +you might be worried when you do this + + + align:start position:0% +you might be worried when you do this +elimination process that well okay we + + align:start position:0% +elimination process that well okay we + + + align:start position:0% +elimination process that well okay we +had to assume a is non zero because we + + align:start position:0% +had to assume a is non zero because we + + + align:start position:0% +had to assume a is non zero because we +wanted a non-zero pivot. You might worry + + align:start position:0% +wanted a non-zero pivot. You might worry + + + align:start position:0% +wanted a non-zero pivot. You might worry +that we might have to have a minus b be + + align:start position:0% +that we might have to have a minus b be + + + align:start position:0% +that we might have to have a minus b be +non zero but in fact a minus b can be + + align:start position:0% +non zero but in fact a minus b can be + + + align:start position:0% +non zero but in fact a minus b can be +zero. + + align:start position:0% +zero. + + + align:start position:0% +zero. +It's not a problem uh for this this + + align:start position:0% +It's not a problem uh for this this + + + align:start position:0% +It's not a problem uh for this this +entry to be zero because we don't have + + align:start position:0% +entry to be zero because we don't have + + + align:start position:0% +entry to be zero because we don't have +to do a row exchange to get U. That's + + align:start position:0% +to do a row exchange to get U. That's + + + align:start position:0% +to do a row exchange to get U. That's +the only time when we can't do the LU + + align:start position:0% +the only time when we can't do the LU + + + align:start position:0% +the only time when we can't do the LU +decomposition. In particular, singular + + align:start position:0% +decomposition. In particular, singular + + + align:start position:0% +decomposition. In particular, singular +matrices can have LU + + align:start position:0% +matrices can have LU + + + align:start position:0% +matrices can have LU +decompositions. Good. + + align:start position:0% +decompositions. Good. + + + align:start position:0% +decompositions. Good. +Okay. Thanks. \ No newline at end of file diff --git a/sd-ZVAw8qB0.txt b/sd-ZVAw8qB0.txt new file mode 100644 index 0000000000000000000000000000000000000000..be1af225903b157c7682d49bf9552482efab20f7 --- /dev/null +++ b/sd-ZVAw8qB0.txt @@ -0,0 +1,267 @@ +Computer systems bring together many technologies +and harness them to provide fast execution + +of programs. + +Some of these technologies are relatively +new, others have been with us for decades. + +Each of the system components comes with a +detailed specification of their functionality + +and interface. + +The expectation is that system designers can +engineer the system based on the component + +specifications without having to know the +details of the implementations of each component. + +This is good since many of the underlying +technologies change, often in ways that allow + +the components to become smaller, faster, +cheaper, more energy efficient, and so on. + +Assuming the new components still implement +same interfaces, they can be integrated into + +the system with very little effort. + +The moral of this story is that the important +part of the system architecture is the interfaces. + +Our goal is to design interface specifications +that can survive many generations of technological + +change. + +One approach to long-term survival is to base +the specification on a useful abstraction + +that hides most, if not all, of the low-level +implementation details. + +Operating systems provide many interfaces +that have remained stable for many years. + +For example, network interfaces that reliably +deliver streams of bytes to named hosts, hiding + +the details of packets, sockets, error detection +and recovery, etc. + +Or windowing and graphics systems that render +complex images, shielding the application + +from details about the underlying graphics +engine. + +Or journaled file systems that behind-the-scenes +defend against corruption in the secondary + +storage arrays. + +Basically, we're long since past the point +where we can afford to start from scratch + +each time the integrated circuit gurus are +able to double the number of transistors on + +a chip, +or the communication wizards figure out how + +to go from 1GHz networks to 10GHz networks, +or the memory mavens are able to increase + +the size of main memory by a factor of 4. + +The interfaces that insulate us from technological +change are critical to ensure that improved + +technology isn't a constant source of disruption. + +There are some famous examples of where an +apparently convenient choice of interface + +has had embarrassing long-term consequences. + +For example, back in the days of stand-alone +computing, different ISAs made different choices + +on how to store multi-byte numeric values +in main memory. + +IBM architectures store the most-significant +byte in the lowest address (so called "big + +endian"), while Intel's x86 architectures +store the least-significant byte first (so + +called "little endian"). + +But this leads to all sorts of complications +in a networked world where numeric data is + +often transferred from system to system. + +This is a prime example of a locally-optimal +choice having an unfortunate global impact. + +As the phrase goes: "a moment of convenience, +a lifetime of regret." + +Another example is the system-level communication +strategy chosen for the first IBM PC, the + +original personal computer based Intel CPU +chips. + +IBM built their expansion bus for adding I/O +peripherals, memory cards, etc., by simply + +using the interface signals provided by then-current +x86 CPU. + +So the width of the data bus, the number of +address pins, the data-transfer protocol, + +etc. where are exactly as designed for interfacing +to that particular CPU. + +A logical choice since it got the job done +while keeping costs as low a possible. + +But that choice quickly proved unfortunate +as newer, higher-performance CPUs were introduced, + +capable of addressing more memory or providing +32-bit instead of 16-bit external data paths. + +So system architects were forced into offering +customers the Hobson's choice of crippling + +system throughput for the sake of backward +compatibility, + +or discarding the networking card they bought +last year since it was now incompatible with + +this year's system. + +But there are success stories too. + +The System/360 interfaces chosen by IBM in +the early 1960s carried over to the System/370 + +in the 70's and 80's and to the Enterprise +System Architecture/390 of the 90's. + +Customers had the expectation that software +written for the earlier machines would continue + +to work on the newer systems and IBM was able +to fulfill that expectation. + +Maybe the most notable long-term interface +success is the design the TCP and IP network + +protocols in the early 70's, which formed +the basis for most packet-based network communication. + +A recent refresh expanded the network addresses +from 32 to 128 bits, but that was largely + +invisible to applications using the network. + +It was a remarkably prescient set of engineering +choices that stood the test of time for over + +four decades of exponential growth in network +connectivity. + +Today's lecture topic is figuring out the +appropriate interface choices for interconnecting + +system components. + +In the earliest systems these connections +were very ad hoc in the sense that the protocols + +and physical implementation were chosen independently +for each connection that had to be made. + +The cable connecting the CPU box to the memory +box (yes, in those days, they lived in separate + +19" racks!) was different than the cable connecting +the CPU to the disk. + +Improving circuit technologies allowed system +components to shrink from cabinet-size to + +board-size +and system engineers designed a modular packaging + +scheme that allowed users to mix-and-match +board types that plugged into a communication + +backplane. + +The protocols and signals on the backplane +reflected the different choices made by each + +vendor - IBM boards didn't plug into Digital +Equipment backplanes, and vice versa. + +This evolved into some standardized communication +backplanes that allowed users to do their + +own system integration, choosing different +vendors for their CPU, memory, networking, + +etc. + +Healthy competition quickly brought prices +down and drove innovation. + +However this promising development was overtaken +by rapidly improving performance, which required + +communication bandwidths that simply could +not be supported across a multi-board backplane. + +These demands for higher performance and the +ability to integrate many different communication + +channels into a single chip, lead to a proliferation +of different channels. + +In many ways, the system architecture was +reminiscent of the original systems - ad-hoc + +purpose-built communication channels specialized +to a specific task. + +As we'll see, engineering considerations have +led to the widespread adoption of general-purpose + +unidirectional point-to-point communication +channels. + +There are still several types of channels +depending on the required performance, the + +distance travelled, etc., +but asynchronous point-to-point channels have + +mostly replaced the synchronous multi-signal +channels of earlier systems. + +Most system-level communications involve signaling +over wires, so next we'll look into some the + +engineering issues we've had to deal with +as communication speeds have increased from + +kHz to GHz. \ No newline at end of file diff --git a/seBwiL9InII.txt b/seBwiL9InII.txt new file mode 100644 index 0000000000000000000000000000000000000000..c731981fb6dbc0ff7a17f9124bee05c7a64fa6aa --- /dev/null +++ b/seBwiL9InII.txt @@ -0,0 +1,3218 @@ +The following +content is provided + +under a Creative +Commons license. + +Your support will help MIT +OpenCourseWare continue + +to offer high quality +educational resources for free. + +To make a donation or to +view additional materials + +from hundreds of MIT courses, +visit MIT OpenCourseWare + +at ocw.mit.edu + +PROFESSOR: As you know, +Professor Guth is away. + +I'm substituting for +today, he didn't leave me + +with a particularly +coherent game plan, + +so I'm going to begin with +where he thinks we should start. + +Please jump in if I am +just repeating something + +that he has already +described to you guys, + +or if there's anything you +like me go over a little bit + +more detail, I will +do my best here. + +So, I'm working off of +a fairly rough plan. + +But let me just +quickly describe what-- + +based on what Alan has explained +to me --what we're planning + +to talk about today, +and if there's + +any adjustments +you think I should + +be making that would be great. + +So, the game plan for today. + +What I want to do +very quickly is + +hit on a couple of +the key points which + +I believe you talked +about last week, + +which is a quick review +of the essential features + +of symmetries of +the gauge fields + +the make up the standard model. + +Now, I believe you +guys did in fact talk + +about this last week, +at least briefly. + +And you talked about how +you can take these things + +and embed them in a larger +gauge group, the group SU(5). + +I'm not going to talk +about that too much, + +but I want to just quickly +hit on a few elements related + +to this before we get into that. + +From this we'll then talk about +the Higgs mechanism-- really + +I'm going to talk +about the Higgs field, + +I'm not going to talk +about the Higgs mechanism + +quite so much as motivate +why it is necessary-- + +and then talk about how +the Higgs field behaves + +and why it's important for +the next problem, which + +is what is called the +cosmological monopole problem. + +To be more specific +magnetic monopole problem. + +I confess I feel a little +bit awkward talking + +about this problem +on behalf of Alan. + +This would be kind of +like if you were planning + +on studying Hamlet and there +was this guy W. Shakespeare who + +was listed as the +instructor and you walk in + +and discover there's this +guy Warren Shackspeare, who's + +actually going to be teaching +or something like that. + +I kind of feel like Warren here. + +This stuff really is Allen's +thing, so it's sort of, + +I'm probably going to leave this +at the denouement of all this + +when you actually get +into inflation to him. + +I may have a little bit of time +at the end to just motivate + +it a little bit, but the grand +summary will come from him. + +OK, so, as discussed by +Alan the standard model + +describes all the +fundamental interactions + +between particles +via gauge theories. + +OK, and these gauge theories +all have a combined symmetry + +group that is traditionally +written in a somewhat + +awkward form, SU(3) +cross SU(2) cross U(1). + +U(1) could be an +SU(1) for reasons + +which I'll elucidate +a little bit more + +clearly in just a moment. + +There's really no point in +putting the S on that one. + +So each of these +things essentially + +labels the particular +symmetry group. + +So, the "S" an +element of SU(n) is + +a matrix that is n x n, that +is unitary-- that's the U. + +Unitary just means that the +inverse and the transpose + +of the matrix at the same, +actually the Hermitian + +conjugate because they +can be complex, in fact, + +they generally are. + +And it has determinant of 1. + +That's what the special refers +to, special, the S in SU(n) + +stands for special unitary n. + +So, the S means +that the determinant + +is one-- that's what's +special about it-- unitary + +is this idea that the inverse +Hermitian conjugate are + +the same, and then n +refers to all these things. + +So, that tells us that the +gauge degrees of freedom + +are related by a symmetry +that looks like a 3 + +by 3 matrix with +these properties, + +as listed there for the +SU(3) piece of the symmetry. + +SU(2) means it's +a 2 by 2 matrix. + +And U(1) means it's a one by one +matrix, what's a 1 by 1 matrix? + +It's a number, its +a complex number. + +And that's why we +don't really need + +to put an "s" in front of it. + +If it's a complex +number its determinant + +is 1 if it's just a complex +number whose modules is one. + +That's why we don't bother +with the S on the U(1). + +So, I think you've already +hit on some of this + +but this is sort of useful +to review because it's + +going to set up why we +need to introduce a Higgs + +mechanism in a little bit. + +Let me just quickly +hit on what the details + +structure of this looks +like for you want to think + +is the easiest one understand, +So, as I just said, + +a one by one matrix is +just a complex number. + +So that means that any +element of this group + +is a complex number, which +we can write in the form z + +equals ei theta, where +theta is a real number. + +Now, the thing which +is I want to hit on + +in this, the reason I want to +describe this a little bit is, + +this may not smell +like the gauge symmetry + +that you're used to if you +study classical E&M. Some of you + +here are in 807 +with me right now, + +and we've gone over this +quite a bit recently. + +How is this akin to the gauge +group that we are normally + +used to when we +talk about the gauge + +freedom of electricity +and magnetism? + +Well, it turns out +there's actually + +a very simple relationship +between one and the other, + +rather between this view +of it and the way we learn + +about it when we study +classical E&M. It's simply + +that we use a somewhat different +language, because when we talk + +about it in this group +theoretic picture we're doing it + +in the way that is sort of +tuned to a quantum field theory. + +So, the way we have learned +about electromagnetic gauge + +symmetry in terms of the +fields sort of goes as follows. + +We actually work with the +potentials, and so what we do + +is we note that the potentials +Amu, which you can write + +as a four vector, whose +time-like component is + +the negative of the +scalar potential, + +and whose spatial +components are just + +the three components of +the vector potential. + +So, this potential and +this potential-- --okay + +this is possibly module of +factor of c somewhere in here + +but I'm going to imagine +the speed of light + +has been set equal to 1. + +Both of those potentials +generate the same E&B fields. + +OK, again you still +should be looking at this + +and thinking to yourself +what the hell does + +this have to do with the +U(1) as we presented it here. + +I've given you a +bunch of operations + +that involve some kind of +a scale or function of time + +and space. + +And I've added particular +components of this four vector + +in this way, what does that +to do with this multiplication + +by a complex number? + +Well, where it comes +from is that when + +we study E&M, not as a +classical field theory + +but as a quantum +field theory, we + +have a field that +describes the electron. + +So, where it comes +from is that when + +you examine the Dirac field, +which is the quantum field + +theory that governs the +electron, when you change gauge + +the electron field acquires +a local phase change. + +So in particular, +what we find is + +that if we have a field +5x, which those of you who + +have taken a little bit +of quantum field theory + +should know this is +actually a spinner field, + +but for now, just think of it +as some kind of a field that + +under the field +equations of quantum + +electrodynamics-- the Dirac +equation or high order + +ones that have been developed +by Feynman, Schwinger, + +and others-- under +a change of gauge + +this goes over to +si prime of x, which + +equals e to the-- +terrible notation + +I realized-- 1e is obviously +the root of natural logs, + +e sub 0 is the fundamental +electric charge. + +OK, can everyone read that? + +I didn't block it too badly here +I'm not used to this classroom. + +So, here's the thing to note, +is that this field lambda, which + +we learned about +in classical E&M + +directly connects to the phase +function of the Dirac field + +in quantum electrodynamics. + +So, our gauge symmetry +is simply expressed + +in the quantum version +of electrodynamics + +by a function of the form e +to the i real number, where + +that real number is the +fundamental electric charge + +times the classical +gauge generator. + +So, this is what is meant when +people say that electrodynamics + +is a U(1) gauge theory. + +Now, I'm not going to go +into this level of detail + +for the other two +gauge symmetry that + +are built into the +standard model. + +But, what I want +you to understand + +is that the root idea +is very, very similar. + +It's just now, instead of my +gauge functions looking like e + +to the i, some kind of a local +gauge phase of x multiplying + +my functions, my +quantities which + +generate the gauge +transformation are going + +to become complex +value matrices. + +So that makes them a +lot more complicated, + +and it's responsible +for the fact + +that the weak and the +strong interactions + +are non-abelian paid which +order you perform the gauge + +transformation in matters. + +Question. + +AUDIENCE: What's the +physical significance + +of them being non-abelian? + +PROFESSOR: Yes. + +So, what is a +physical significance + +of them being non-abelian? + +I'm trying think of a really +simple way to put this, + +it's-- Alan would have an +answer to this right off the top + +of his head, so I +apologize for this-- + +this isn't the kind of thing +that I work on every day so I + +don't have an answer right +at the very top of my head, + +unfortunately. + +Let me get back to +you on that one, OK, + +that's something I can't +give you a quick answer to. + +It's an excellent question and +it's an important question. + +Any other questions? + +OK, so, here's a basic +picture that we have. + +So, we find is that the +strong interactions have + +a similar structure where +my need to e to the i factor + +goes over to a 3 by 3 matrix, +and the weak interactions + +in a similar structure with my +e to the i factor going over + +to a 2 by 2 complex matrix. + +OK, what does this have +to do with cosmology? + +In fact, as an enormous +amount to do with cosmology, + +as we'll see over the course +of the rest of course. + +Part of the thing which is +interesting about all this + +is that we have strong +experimental reasons, + +and theoretical +reasons to believe, + +that the different symmetries +that these interactions + +participate in, the +different symmetries that we + +see them having, that isn't the +way things have always been. + +So, in particular when the +universe was a lot hotter + +and denser these different +symmetries actually + +all began to look the same. + +In particular the one which +is particularly important, + +and you guys have surely heard +of this, is that the SU(2)-- + +if we just focus on electric +and the weak piece of this-- + +SU(2) cross U(1). + +So, this is associated +with the gauge boson that + +carry the weak force, OK, the +z boson, the w plus, and the w + +minus. + +And your U(1) ends up being +associated with the photon. + +In many ways, when +you actually look + +at the equations that +govern these things, + +they seem very, +very similar to one + +another except that +the-- here's partly + +an answer to your +question I just + +realized-- the gauge +generators of these things + +have a mass +associated with them. + +That mass ends up +being connected + +to the non-abelian +nature of these things. + +That's not the whole answer, +but it has a connection to that. + +That's one thing +which I do remember, + +like I said I feel +this is really + +Alan's perfect framework +here and I'm just + +a posture in bad shoes. + +So if we look at this +thing, what we see + +is that these symmetry groups, +what's particularly interesting + +is that U(1) can be regarded +as a piece of SU(2). + +And we would expect +that in a perfect world + +they would actually +be SU(2) governing + +both the electric and +the weak interactions. + +Whereby perfect +I mean everything + +is a nice balmy 10 to the 16th +GeV throughout all of space + +time, and all the different +vector bosons happily + +exchange with one another, +not caring with who is who. + +It's actually not +very perfect if you + +want to teach a physics class +and have a nice conversation, + +but if you are interested in +perfect symmetry among gauge + +interactions it's +very, very nice. + +So, the fact that +these are separate + +is now-- I was about to use the +word believed but it's stronger + +and that, we now know +this for sure thanks + +to all the exciting work +that happened at the LHC + +over the past year or two-- the +fact that these symmetries are + +separate is due to what is +called spontaneous symmetry + +breaking. + +So, let's talk very +briefly about what + +goes into this spontaneous +symmetry breaking. + +So SU(2) turns +out to actually be + +isomorphic to the group +of rotations on a sphere. + +So, when you think +about something + +that has perfect +SU(2) symmetry it's + +as though you have perfect +symmetry when you move around + +through a whole host +of different angles. + +OK, so you move through all +of your different angles + +and everyone looks exactly +identical to all the others. + +If you break that +symmetry it may + +mean you're picking out +one angle as being special, + +and then you only retain +a symmetry with respect + +to the other angle. + +And essentially, that is what +happens when SU(2) breaks off + +in a U(1) piece of it. + +Something has occurred +that picked out + +one of these directions. + +And by the way, you have to +think very abstractly here. + +This is not necessarily a +direction in physical space + +we're talking +about here but it's + +a direction in the +space of gauge fields. + +So, if we imagine that all of +these, my gauge fields in some + +sense the different +components of them defined + +in some abstract +space direction, + +initially these +things are completely + +symmetric with +respect to rotations + +in some kind of an abstract +notion of a sphere. + +And then something +happens to freeze + +one of the directions +and only symmetries + +with respect to one of the +angles remains the same. + +Let's just write that +out, when SU(2)'s symmetry + +is broken so one of the +directions in the space + +of gauge fields is +picked out as special. + +That direction +then ends up being + +associated with +your U(1) symmetry. + +So, what is the mechanism that +actually breaks the symmetry + +and causes this to happen. + +Well, this is what the +Higgs field is all about. + +The idea is there is some field +that fills all of space time. + +It has the property that +at very high energies + +it is extremely symmetric, +with to respect all these gauge + +fields, all directions and +sort of gauge field space + +look exactly the same. + +And then as things cool, as +the energy density goes down + +by the temperature of the +expanding universe, cooling + +everything off, the Higgs field +moves to a particular place + +that picks out some direction +in the space of gauge fields + +as being special. + +So let's make this a +little bit more concrete. + +OK. + +You guys have probably heard +quite a lot about the Higgs + +field over the +past couple years, + +months-- what actually is it? + +Well, the field itself is +described by a complex doublet. + +So, if you actually see someone +write down a Higgs field what + +they will actually +write down is h, + +being a two components +spinner, whose components are + +h1 of x, h2 of +x-- where x really + +stands for space time +coordinates, so that's time + +and all of your +spatial coordinates-- + +and both h1 and h2 +are complex fields. + +The thing which is particularly +key to understanding + +the importance of this +thing is that h transforms, + +under gauge transformations, +with elements of SU(2). + +So, if you want to +change gauge the way + +you're going to do it is you're +going to have some new Higgs + +field. + +So remember, if U(2) +is an element of SU(2) + +we call it the +two by two matrix. + +This is what they look like +in a new gauge OK-- pardon me + +a second I don't see +a clock in this room, + +I just want to make sure I +know the time, thank you. + +OK, so, what are we +going to do with this? + +Well, there's a couple +features which it must have, + +so the Higgs field +fills all of space time + +and it has an energy +density associated + +with it, which we will call +just the potential energy. + +It's really an energy +density, but, whatever. + +The energy density that is +associated with this thing + +must be gauge invariant. + +OK, even when you're +working with strong fields + +and weak fields, the lesson +of gauge invariance from E&M + +still holds. + +OK, one of the key points was +that the gauge fields affect + +potentials, they allow us +to manipulate our equations + +to put things into a form where +the calculation may be easier. + +But at the end of the day, there +are certain things it actually + +exert forces that +cause things to happen, + +those must be invariant to +the gauge transformation. + +Energy density is +of those things. + +If you were to get +into your spaceship + +and go back to +the early universe + +and actually take a little +scoop of early universe out + +and measure the energy density, +A, that would be cool, but B + +it would be something +that couldn't actually + +depend on what +gauge you were using + +to make your measurements. + +That is something that is +a complete artifice of how + +you want to set +up the convenience + +of your calculation. + +So, in order for the energy +density to be gauge invariant + +we have to find a gauge +invariant quantity that + +is constructed from this, which +is the only thing the energy + +density can depend on. + +This means, let's call +our energy density V, + +it's the potential +energy density. + +So, it can only depend on +the following combination + +of the fundamental fields Pretty +much just what you'd expect. + +This is sort of the +equivalent to saying + +that if you're working +in spherical symmetry + +the electrostatic +potential can only + +depend on the distance +from a point charge. + +This is a very similar +kind of construct + +here, where I'm taking +the only quantity that + +follows in a fully +symmetric way, of calling + +the fact that this is a +special unitary matrix that I + +can construct from these things. + +So then, where all +the magic comes + +in is in how the Higgs field +potential energy density + +varies as a function of +this h, this magnitude of h. + +So, as I plot v as +a function of h, + +in order to get your +spontaneous symmetry breaking + +to happen what you want +is for the minimum of V, + +the minimum potential +energy, to occur somewhere + +out at a non-zero value +of the Higgs field H. + +Now, why is that so special? + +The thing that is so +special about that + +is that when I constructed +this magnitude of h, + +I actually lost a +lot of information + +about the Higgs field. + +OK, let's just say for +the sake of argument + +that this minimum +occurs at a place where + +the Higgs field in some system +of units has a value of 1. + +So, all I need to do +is as my universe cools + +what I'm going to +want is energetically, + +my potential is going to want +to go down to its minimum. + +So, that just means that as +the universe is cooling, maybe + +at very, very early times +when everything is extremely + +hot and dense, I'm up here +where the potential energy is + +very high. + +As the universe expands, +as everything cools, + +it moves over to +here, it just moves + +to someplace where the Higgs +field takes on a value of 1. + +And that's exactly correct, +that is what ends up happening. + +But remember, the minimum +occurs at some value + +in which the magnitude +of this field + +does not equal zero, but given +that value-- where again let's + +just say for this for +sake of specificity + +that we set it equal to +the magnitude of this thing + +equal to 1 in some +units-- there's actually + +an infinite number of +configurations that correspond + +to that because this +is a complex number, + +this is a complex number. + +I could put it all +into little h1, + +and I could set into the value +where that thing is completely + +real, or I could put it all +into little h2 being completely + +imaginary or all on to h1 being +all imaginary, halfway into h1, + +halfway into h2. + +There are literally an +infinite number of combinations + +that I can choose +which are consistent + +with this value of the +magnitude of H. So, yeah-- + +AUDIENCE: So, I +don't know if I'm + +putting too much physical +significance on the gauge, + +but with the other cases +of spontaneous symmetry, + +briefly, that we discussed +you can always measure. + +OK, I've broken my symmetry, +and now it's lined up this way, + +or there's something measurable. + +Now, the field +has to be physical + +because the fact that +you have gauge symmetry + +gives you some concerned +quantity, right? + +But, how can I measure what +direction in gauge space + +that I picked out? + +PROFESSOR: So, that +is, let me talk + +about this just a +little bit more. + +I think answering your +question completely + +is not really +possible, but there + +is a residue of that is +in fact very interesting, + +and let me just lay out a couple +more facts about what actually + +happens with this +gauge symmetry, + +and it's not going to +answer your question + +but it's going to give you +something to think about. + +OK, so that's an excellent +and very deep question, + +and there are really +interesting consequences. + +And this is a case +where my failure + +to answer the previous +one is because there's + +details I can't +remember, in this case, + +I think it's because +there's details we actually + +don't understand fully. + +Research into the mechanism of +electroweak symmetry breaking, + +which is what this +is all about, is + +one of the hot topics in +particle physics right now. + +AUDIENCE: I was just +wondering if gravity + +has any gauge symmetry +associated with it. + +PROFESSOR: It does, but it fits +in a very, very different way, + +and with the exception of the +fairly speculative framework + +of string theory-- which I +think is very, very promising, + +but it's just +sufficiently removed + +from experimental +verification that I'm + +going to have to label it +speculative-- it doesn't quite + +tie in in the same way. + +And that's the best +I can say right now. + +The gauge symmetries +of general relativity + +are, at the classical +level, they correspond + +to coordinate transformations, +at a quantum level, + +there's not such a +simple way to put it. + +All right, where +was I, OK, sorry + +I didn't get to your question. + +So, the point we made here is +that we have spontaneously, + +when we actually choose which +one of these infinite number + +of values we're going +to have, we just + +randomly break the symmetry. + +OK, and you guys +apparently have already + +talked a little bit about +spontaneous symmetry breaking. + +The analogy that +people often make + +is to the freezing +of water, OK, prior + +to the water entering its +solid phase its completely + +rotationally symmetric, +then at a certain point + +crystalline planes +start to form, + +the water forms, +all the molecules + +get set into a +particular orientation, + +you lose that +rotational symmetry. + +In this case, we started +out with a theory, + +with a set of interactions +that were completely symmetric + +in sort of gauge field space. + +And now by settling +down and picking + +a particular special +value of h1 and h2 + +we have at least nailed +down one direction. + +It's like we've defined +a crystalline plane, + +and so now things, suddenly, +aren't as symmetric. + +And we start to pick +out preferred directions + +in our gauge fields. + +What we can do +with this is really + +a topic for a +whole other course, + +and that course is called +quantum field theory, + +but I will sketch a +couple of the consequences + +and this gets directly to +the answer your questions. + +So, one of the +consequences of this + +is that once we have picked +out a particular direction, + +electrons and neutrinos +are different. + +When the Higgs field +is equal to zero + +there is no difference between +an electron and a neutrino. + +They obey exactly +the same equation, + +there's literally no +difference between them. + +Once we have actually +settled on an h1 and an h2 + +some combination of the +fundamental underlying fields + +comes together, acquires a mass, +acquires an electric charge, + +and we say A-HA thou +beist an electron. + +It wasn't like that in the +original unbroken symmetry. + +AUDIENCE: Also, [INAUDIBLE]? + +PROFESSOR: Presumably, +but I'm going + +to stick with just +these for now, + +but I've I'm pretty sure +that's the case, yeah. + +That gets into even more +complications of course + +because the additional +generations are actually + +consequence presumably of some +broken higher level symmetry, + +which is even poorly, +more poorly understood. + +But you raise a good point. + +So, that's one partial +answer your question. + +How one can actually +walk that backwards + +to understand this thing +about the initial state? + +That's hard to say. + +I actually think +this particular one + +is one of the profound +and interesting aspects + +of this, in part because we now +know the neutrino has a mass. + +We have no idea what that is, +and in fact we only really + +have bounds on the mass, such +that we know it is non-zero, + +and we have upper +limits that are + +set by very indirect +measurements. + +But the actual +values of the mass + +are very, very +poorly constrained. + +Within the standard +model you just + +take the electroweak +interaction, + +introduce a Higgs coupling +and allow the symmetry + +to be spontaneously broken, +the neutrino mass is zero. + +Full stop zero. + +So something's not +right, we're actually + +missing something here. + +People have kind of jury +rigged the standard model + +to put in the masses by +hand, and it works OK, + +but it's not +completely satisfying. + +And a lot of experiments +going on right now + +to explore the neutrino +sector are hopefully + +going to open us up to a +deeper understanding of this + +and may say a lot about all this +physics, which is at present, + +pretty poorly understood. + +The consequence, which has +received the most popular + +press, and what you +guys have certainly + +seen about in newspapers, +given the results that came out + +from the LHC over the past year +is that quarks and leptons have + +mass, or put more +specifically, rest mass. + +To understand what +this actually means + +I think you really need to +ask yourself what is mass + +meant to be. + +Well, the idea is you calculate +the spectrum of oscillations + +associated with the +fields of your theory, + +and then if your theory +predicts a discrete spectrum + +of oscillations, it doesn't +even have to be discrete + +but predict some +spectrum of oscillations, + +then for every oscillation +frequency omega + +there's an associated +mass that is just + +H bar omega over c squared. + +If your omega has +some lower bound that + +is greater than zero, +then your theory + +has particles with +nonzero rest mass. + +Without going into the +details-- and this again + +is something which +those of you who + +are going to go on to study +this in more detail in a higher + +level course, which is +fairly standard stuff is done + +in probably the first or maybe +late in the first or early + +in the second semester of a +typical quantum field theory + +course-- what you'll find is +that when the Higgs field is + +zero then quarks +and leptons have, + +the field that describes quarks +and leptons-- and yes including + +mu and tau, so including +all the leptons, this one + +I'm very confident +on-- the spectrum + +goes all the way to zero +if the Higgs field is zero. + +But when the Higgs field becomes +non-zero, roughly speaking, + +it shifts the spectrum +over for these particles. + +There's an interaction between +the things like the electron + +field in the Higgs field or the +up quark field and the Higgs + +field, which shifts the +spectrum over just enough + +so that the frequency +is never allowed + +to go below some minimum. + +AUDIENCE: Going back +a bit, I'm confused + +about how picking a specific +value to the Higgs field + +is breaking SU(2) +symmetry and not U(1), + +because it seems like we're +fixed on a circle, right? + +PROFESSOR: That's right what +U(1) is a symmetry on a circle, + +SU(2) is kind of like symmetry +on a sphere, essentially. + +AUDIENCE: Right, so how are we +not picking a specific value + +[INAUDIBLE] circle [INAUDIBLE]? + +PROFESSOR: Well, what we're +doing is, think of it this way, + +imagine SU(2) is a +symmetry on a sphere, + +and then when we break +the SU(2) symmetry + +it's like we're picking +some circle on that sphere. + +So, we've broken one circle, +we've picked one circle, + +but now we're allowed +to go anywhere + +on that remaining circle, +which is a U(1) symmetry. + +Does that help? + +Yeah, OK good. + +And it comes down to the +fact if you sort of count up + +your degrees of freedom, +it has to do with the fact + +you you've got four, you +have two complex numbers, + +so there's four real parameters +associated with this thing, + +and they are isomorphic to sort +of rotations in a three space + +and you're adding +one constraint. + +OK, so let me just finish +making this point here again. + +So, when h does not +equal zero, spectrum + +get shifted for the +quarks and leptons, + +so everything picks up +a little bit of a mass. + +And the final one, +final consequence + +which we're going +to talk about today, + +is that the universe is filled +with magnetic monopoles. + +We all remember studying +Maxwell's equations + +learning that del dot +b is equal to 4 pi + +times the density +of magnetic charge-- + +this all makes +perfect sense, right? + +Well, this is actually something +that when it first sort of came + +out and people begin to +appreciate this thing with sort + +of a "Um, well everything +else works so well, + +maybe we're just not +looking hard enough. " So, + +it was a bit of a surprise. + +So, where do these magnetic +monopoles come from? + +And essentially, the +magnetic monopoles + +are going to turn out to be +a consequence of the fact + +that when spontaneous +symmetry breaking happens + +it doesn't happen +everywhere simultaneously. + +So, think again about-- yeah? + +AUDIENCE: Doesn't that +bring up possibility + +that the symmetry could +break in different ways + +in different places? + +PROFESSOR: That is in +fact exactly what this + +is going to be. + +Magnetic monopoles are in +fact exactly a consequence + +of this, yes. + +Give me a few +moments to step ahead + +to fill in a couple of the +gaps, but you're basically + +already there. + +So, think about crystalline +crystal formation again. + +Imagine you have, +we could do ice + +if you like or choose something +that's got a little bit more + +of an interesting +crystalline structure. + +Imagine you have a big bucket +full of molten quarts, OK. + +So, if you have a +big thing of quartz + +that you want to sort of freeze +into a single gigantic crystal, + +what you typically do if +you'd like to do this is + +you actually seed +it with a little bit + +of a starter crystal. + +So, you put a little bit +of crystal into this thing, + +and what that does is it sort of +defines a preferred orientation + +of the crystal axes, +so that as things + +start to cool in the +vicinity of that they have + +a preferred orientation +to grab on to. + +And that seed then +gradually gets + +bigger and bigger and bigger, +and all the little crystals + +as they form near +it tend to latch + +onto the preexisting +crystalline structure, + +and that allows you +to grow actually + +extremely large crystals. + +I don't know if anyone here is +doing a year off with the LIGO + +project but these guys have to +make these sort of 100 kilogram + +mirrors of very pure either +Sapphire or silicon dioxide, + +and when you make 100 +kilograms of crystal + +you need to build it +really, really carefully. + +It's extremely important +for the optical purposes + +that all the axes +associated with the crystal + +will be pointing in +the right direction. + +Otherwise you spend +$100,000 on this thing + +and it ends up being the +world's prettiest paperweight. + +So, similar things happen +when the Higgs field cools. + +Let's imagine that +we've got our universe, + +time going forward like this, +and at some point over here + +the universe cools enough +that's the Higgs field condenses + +into some particular direction. + +And symmetry is spontaneously +broken right at this one point + +over here. + +So, I'm going to draw +my diagram over there + +and put some words over here. + +I shouldn't say Higgs +field cools enough, + +the universe cools +enough so that the Higgs + +field breaks the symmetry. + +So, just to be concrete, let's +imagine that at 0.1 over here + +it takes on a field of the +value one for h1 and I for h2. + +So just for concreteness +imagine it looks something + +like this at this point. + +And so what happens is as +the university continues + +to expand other areas +are going to cool off. + +The bits that are +closest to it are + +going to see that +there is already + +a preferred orientation +defined by the Higgs field. + +And so it's energetically +favorable for those regions + +of the universe to fall +into the same alignment + +and so there'll be a +region in space times + +that grows here as the universe +cools, in which the Higgs + +field all falls into +this configuration, which + +I will call h1. + +But suppose somewhere +over here at 0.2, + +and the key thing is +that initially 0.2 + +is going to be so far away +from 0.1 that these points are + +out of causal contact +with one another. + +I can not send a message +from event one to event two. + +The Higgs field +also reaches a point + +that the universe cools enough +that at 0.2, just you know, + +it's a system that's not +in thermal equilibrium. + +So, some places are +going to be a little bit + +hotter than others, +some are going + +to be a little bit cooler. + +And so, at these two +points it just so happened + +that the Higgs field +got to the point + +where it could spontaneously +break the symmetry. + +So at 0.2 the Higgs field +also got to the point + +where it could spontaneously +break its symmetry. + +And the only thing +that's got to happen + +is, remember the only +constraint we have is + +that the magnitude +of the Higgs field + +be equals to some value-- I +should normalize that to root 2 + +in units I want to +use but whatever. + +Let's say on this one +my h1 is equal to y, + +and h2 is equal to minus 1. + +So, it's basically +the same thing + +but all the fields +are multiplied by i. + +It's the same +magnitude, so it's going + +to have the same +potential energy. + +So that's cool. + +Clearly this is allowed, +and now all the regions + +in the universe that +are close to the this + +are going to sort of smell +this particular arrangement + +of the Higgs field +and say OK, that's + +preferred arrangement +I want to go into. + +So, we have two separate +values of the Higgs field + +that are happily swooping +out space time here. + +This gets to the +excellent question + +I was just asked a moment ago-- +what happens when they collide? + +As the universe expands +and gets cooler, all of it + +is going to end +up getting swooped + +into either the field that +was seeded at event one, + +or the field that was +seeded in to event two, + +but at a certain +point we're going + +to get the bits where they're +smashing into one another. + +So what happens when these +different domains come + +into contact with one another? + +The absolutely full +and probably correct + +answer is we don't know. + +The reason is that we don't +really, to be perfectly blunt, + +fully understand every little +detail about the symmetry + +breaking, or about the +structure of whatever + +grand unified theory brings +all these things together + +at the temperatures at +which this is happening. + +Because this is happening +when the universe has + +a temperature of like +10 to the 16th GeV. + +And so it's way +beyond the domain + +of where we can push things. + +But we can, as physicists +are fond of doing, + +we can paramaterize +our ignorance, + +and we can ask +ourselves, well what + +happens if these various +parameters that characterize + +my grand unified theory take on +the following plausible kinds + +of parameters. + +And what we find is +that generically, + +when you have two different +domains where the Higgs + +field takes on different +values like this, when + +these domains come +into contact you + +get what are called +topological defects. + +The topological defects come +in three different flavors. + +To understand something +about those flavors + +you have to know a +little bit about what + +happens in general when +you have phase transitions, + +and different regions +of your medium + +go through a phase transition +with different values + +of the parameters. + +So, it's a general +case that whenever + +you have some kind +of a phase transition + +and you have domains +of different phase + +that come into contact +with one another, + +your field will attempt +to smoothly match itself + +across the boundary. + +But that can be very difficult. + +So if you imagine these +particular two cases + +that I have here, +that's essentially + +saying that when +these two domains + +coming to contact +with one another + +there's going to be sort +of a transition zone + +where the field is +attempting to rotate + +from one value of the +Higgs to the other. + +And it's going to pick some +value that is in some sense + +intermediate to +those two things. + +So that, let's say we +continue these up here, + +so that the collision is +occurring right in this place + +here, in this little locus +of events in space time. + +I have Higgs field 2 over +here, Higgs field 1 over here, + +and I've got some crazy +intermediate field that + +goes between the +two of them, which + +is trying to sort of force +itself to smoothly transition + +from one to the other. + +In so doing, I might end +up pushing my field away + +from the minimum, in +which case there will then + +be some energy +trapped in that layer. + +And there's a reason we +do this level the class + +in a bit of a hand +wavy way, I mean + +it's very, very complicated +to get the details right. + +But the key thing we see is +that in doing this match, + +the field has to do some +pretty silly shenanigans order + +to make everything +kind of match up + +and we can be left with +odd observable consequences + +from the energy associated +with the Higgs field getting + +pinned down at +that boundary here. + +Now, the details of the +forms of this boundary + +vary a lot depending upon +to the specific assumptions + +you make about your underlying +grand unified theory. + +OK, so I should +back up for a bit. + +I'm sort of assuming here when +I discuss all this that there + +is some underlying SU(5) +theory which describes + +the strong weak and +electromagnetic interactions + +are very, very high temperatures +as one gigantic thing. + +And we're getting +to the point now + +where all the different +interactions are beginning + +to just sort of +crystallize out of it. + +There's a lot of different ways +you can pack your underlying, + +fundamental, what we now think +of as our standard model, + +into SU(5) grand +unified theories. + +And so the ways in +which we can get + +different topological +defects depend + +upon how we choose to do that. + +So defect flavor one is you get +something called a domain wall. + +When we do this +the fields attempts + +to make itself smoothly match +from one region of Higgs field, + +say from Higgs 1 to Higgs 2. + +It succeeds, but +you end up with kind + +of a two dimensional structure-- +a wall-- in which there's + +some kind of anomalous field +that is just pinned down there. + +And so we end up +with a big sheet. + +So in a theory +like this, it would + +predict that somewhere out +in the universe if there were + +regions in which the +Higgs field had taken + +on a different +value than the one + +that we encounter +around us right now, + +it could be somewhere out +gigaparsecs away, essentially + +a giant sheet of some kind. + +And there would be +weird, anomalous behavior + +associated with it. + +People have really +looked long and hard + +to try to find things +like this and in fact it + +would be expected to leave +interesting residuals + +in the cause of +microwave background. + +My understanding +of the literature + +is that there are +actually now very + +strong bounds on the +possibility of having + +a grand unified theory +that leads to domain walls. + +And so this kind of +a topological defect + +is observationally disfavored. + +So this, I should +mention, only occurs + +in some grand unified theories. + +Basically, As we move on to +the other flavors of defects + +we end up just going down a step +in dimensionality associated + +with the little kinks +that are left over when + +the different domains come +into contact with one another. + +Flavor two, we would get +what's called a cosmic string. + +Some of you may +have heard of this. + +This is essentially, at its +core, just a one dimensional, + +it could be gigparsecs long, +but one dimensional, truly + +one dimensional-- +essentially just + +a point in the other two +dimensions-- string of mismatch + +Higgs field with some kind of +an energy density associated + +with it when the different +domains get in contact. + +AUDIENCE: Do we +have any estimate + +of how close in actual space +these different regions would + +have started? + +PROFESSOR: We do and I'm +actually going to get to that. + +So, let me give you +two answers to that. + +One of them is you are going +to estimate that apparently + +on PSET 10, according to the +notes that Alan left for me. + +But I'm going to spell out +for you the arguments that + +go into it in the last +10 minutes of a class. + +But yeah, so let me just quickly +finish up this one because this + +again-- so a cosmic string is +sort of like a one dimensional + +analog of a domain wall. + +And because it would be +this sort of long one + +dimensional structure, that +has actually up a lot of energy + +sort of pinned down to it +by the fact it has a Higgs + +anomaly associated with it, it +would be strongly gravitating + +and so it would leave really +interesting signatures. + +It was thought for a while +that cosmic strings might + +have been the sort of original +gravitational anomalies + +that seeded some of +the structures we see + +in the universe today. + +Again, it's now pretty +highly disfavored. + +If cosmic strings +exist, they don't + +appear to contribute very +much to the budget of mass + +in our universe. + +I should also mention +that this is only + +predicted by some grand +unifying theories. + +If you guys are +curious about this + +I suggest when Alice +back you ask him + +what the difference +between these sums, + +why some predict a +domain wall, some + +predict the cosmic strings. + +Flavor three is where +you end up with the Higgs + +field essentially being +able to smoothly transition + +without leaving any defect +anywhere except at a zero + +dimensional point. + +So you end up with just a +little knot in the Higgs field. + +And for reasons that I +will outline very soon, + +it turns out that this little +not must carry magnetic charge, + +and so it must be a +magnetic monopole. + +The domain walls and +the cosmic strings + +are, as I've emphasized, +only predicted + +by certain specific +grand unified theories. + +Magnetic monopoles are actually +predicted by all of them. + +Question. + +AUDIENCE: What does it mean to +have a one dimensional domain + +wall, because there's no +different region separated + +by one [INAUDIBLE]. + +PROFESSOR: That's right. + +So what ends up +happening, and this + +is where I think +you're going to have + +to ask Alan to sort of follow +up on this a little bit. + +So, as the domains come into +contact with one another. + +The fields do their best to +smoothly transition from one + +to the other. + +And grand unified theories +that predict a cosmic string, + +they succeed pretty +much everywhere. + +They're able to actually +smoothly make it all go away + +so you don't end up with +feel being pinned down + +anywhere, except in a little +one dimensional singularity that + +is somewhere along where the two +dimensional services originally + +met. + +And that is-- +there's details there + +that I'm not even +pretending to explain. + +And as I say, those +are only predicted + +by certain kinds of +grand unified theories. + +All of them will then predict +that even if you don't have + +that, that cosmic string +will then shrink itself down + +and it'll just be left with +a little knot of Higgs field, + +where there's a little +bit of residual mismatch + +between the two regions. + +AUDIENCE: Do all three +types of defects carry + +a magnetic charge, +or only the knots? + +PROFESSOR: I think +only the knots. + +They do carry other +kinds of fields, + +though, in particular the +other ones gravitate, in fact + +all them gravitate, +and so that's + +one of the ways in +which people have + +tried to set observational +limits on these things. + +In particular +there have recently + +been a fair amount of +work of people trying + +to set limits on cosmic strings +from gravitational lensing, + +and there was really +a lot of excitement + +because people thought they +discovered want a couple + +years ago. + +And they saw +basically two quasars + +that looked absolutely +identical, that were separated + +or scale that was just +right to be a cosmic string. + +And then people actually looked +at with better telescopes, + +and saw they had absolutely +nothing to do with one another. + +They were not cosmic, they were +not lenses, it's just every now + +and then God is +screwing with you. + +OK, so without going into some +of the details what you have, + +these little point like +defects-- and I'm short on time + +so I'm going to kind of go +through this a little bit + +in a sketchy way enough so +that I can pay for you how + +to do some calculations +you're going to need to do. + +So the point like defects +end up being regions, + +where at that point the +Higgs field actually takes + +the value zero. + +So remember I was describing how +when you have two regions where + +the Higgs fields are both +taking on values such as there + +at the minimum of the +Higgs potential energy, + +and they come in to +match one another, + +and what we have a +boundary condition + +that very far away the +Higgs field has values + +such as the energy is minimized. + +And there is a theorem, which +in his notes Alan-- the way + +he describes it is +he gives you a figure + +and outlines the +various things that + +are necessary for the +theorem to be true, + +and invites you to think +deeply for a moment + +and until insight +comes to you, I guess. + +And when you put this ingredient +that the Higgs field has + +this asymptotic, very far +away value that drives you + +to the minimum of the field, +and yet it must change value + +somewhere in the +middle, the theorem + +requires that there be one +point at which H equals 0. + +And apparently, this +is a consequence + +in all grand unified theories. + +So, recall, H equals 0. + +This is a point at which +the potential energy + +density can be huge. + +So, when you have a little +point like defect like this, + +it looks like a massive nugget, +little massive particle. + +You can in fact calculate +the total amount + +of energy associated +with this particle. + +If you do so just including the +influence of the Higgs field, + +the calculation +basically goes like this. + +It's very similar to the way we +calculate the energy associated + +with electric and magnetic +fields in electrodynamics. + +Ask yourself, how much +energy is contained + +in a sphere of +radius, capital R, + +centered on this little +knot of Higgs field. + +Well, it's going to +look like 4pi times + +an integral of the +gradient of the Higgs field + +squared r squared +dr It turns out, + +when you calculate the +[INAUDIBLE] of the Higgs field + +around one of these +little defects, + +it's actually very complicated +close to the defect, + +but as you get far away +it has a very simple form. + +The gradient goes +as 1 over r, it + +tells you the field +itself actually + +goes something like log. + +That means your energy looks +something like, R squared, + +1 over R squared dr which goes +as R, which diverges as you + +make the sphere bigger +and bigger and bigger. + +So, what's the mistake we made? + +Well, the Higgs +field doesn't always + +just sit there and +operate on itself. + +The Higgs field actually +couples pretty strongly + +to all of our vector bosons. + +Particularly, it +couples pretty strongly + +to electric and magnetic fields. + +So, we have to repeat +this calculation including + +the interaction of the Higgs +field with the E&D field. + +And in Alan's notes he +gives you some references + +on this because this is not +the kind of calculation you + +can really sketch +out very easily + +in an undergraduate class. + +To make this +integral convergent, + +the only way it can be done +is if that little nugget + +of Higgs field is endowed +with magnetic charge. + +You need to have a monopolar +magnetic field that ends up + +putting in interaction +terms, that + +make the divergence of +this integral go away. + +So, I at last get to the +punchline of all this, + +we are left inevitably, if we +accept the whole foundation + +story of particle physics that +the different interactions were + +unified in some high energy +scale and then froze out. + +We are driven +inevitably to the story + +that defects in the Higgs field +create magnetic monopoles. + +Now, I realize I'm out of time, +so let me just quickly sketch + +a few interesting +facts about this + +and there's a few exercises +that you guys are apparently + +going to look at in your +homework assignment. + +When we do this +calculation, one which + +is I believe just +referenced in the notes + +that Alan has for the +class, we learn a couple + +of things about this +magnetic charge. + +One of them is that if you +work in the fundamental unit, + +say CGS units, the value +of the magnetic charge, + +we'll call that g, +is exactly 1 over + +2 alpha where alpha +is a fine structure + +constant, times the +electric charge. + +So if you have two +magnetic monopoles + +they attract each +other with a force + +that is-- so 1 over 2 alpha is +approximately 68.5 I think-- + +and so it would be 68.5 +squared times the force of two + +electric charges at +that same distance. + +We also end up +learning the mass. + +It turns out to be 1 over alpha +times the scale of GUT symmetry + +breaking. + +Anyone recall what the scale +of GUT symmetry breaking is? + +10 to the 16 GeV. + +So, this is a particle, 1 +over alpha is approximately 10 + +to the two, so this +is a particle that + +has a mass of about +10 to the 18th GeV, + +in other words it's a single +particle with a mass of 10 + +to the 18th protons. + +This is approximately +one microgram. + +If you put one of these things +on a scale it could measure it, + +that's bloody big. + +So getting to the last bit +of the class, which I am just + +going to very basically +quote the answer. + +The question becomes how often +do these things get created + +and here I'm going to +refer to Alan's notes. + +What you'll find +is that, remember + +when we sketched our original +picture of this thing + +we looked at regions +of the universe + +where the Higgs +field was initially + +seeded with different values. + +In order for the Higgs field +to take on different values, + +initially, these regions had +to be out of causal contact + +with one another. + +So we are going to require +that the initial seed areas be + +separated by a distance, +which is the correlation + +length, which has to +be less than or of + +order the horizon distance. + +You can get a lower bound on +this thing by imagining that + +it's-- sorry let me +say one other thing. + +If you do that, then you +can estimate that the number + +density associated +with these things, + +the number density +of these monopoles + +will be 1 over the +correlation length cubed. + +To get a lower +bound on the number + +density of these things, set +the correlation length exactly + +to the horizon distance, and +then do the following exercise. + +So first, let's set +up the correlation + +length equal to the +horizon distance. + +Set the density in monopoles +equal to the mass of a monopole + +over rH cubed, normalized +to the critical density. + +If you do this, +you will find that + +just due to magnetic +monopoles alone, + +the density of the universe. + +PROFESSOR 2: Excuse +me, professor + +PROFESSOR: Yes, I'm wrapping +up right this second. + +PROFESSOR 2: It's seven minutes. + +You were supposed +to end at 10:55. + +PROFESSOR: I'm substitute +teaching, I'm sorry. + +OK, so this tells +us that we are at 10 + +to the 20 of the +critical density. + +And a consequence +is that the universe + +is approximately two years old. + +I will let Alan pick +it up from there. \ No newline at end of file diff --git a/sfH3Jw6LZm8.txt b/sfH3Jw6LZm8.txt new file mode 100644 index 0000000000000000000000000000000000000000..f31c02e967146927c871cafb1a588a094ad1111b --- /dev/null +++ b/sfH3Jw6LZm8.txt @@ -0,0 +1,787 @@ +align:start position:0% + +where do forces come from all forces + + align:start position:0% +where do forces come from all forces + + + align:start position:0% +where do forces come from all forces +arise from the interaction of two + + align:start position:0% +arise from the interaction of two + + + align:start position:0% +arise from the interaction of two +objects with each other in this example + + align:start position:0% +objects with each other in this example + + + align:start position:0% +objects with each other in this example +we have two objects one and two + + align:start position:0% +we have two objects one and two + + + align:start position:0% +we have two objects one and two +interacting with each other in this case + + align:start position:0% +interacting with each other in this case + + + align:start position:0% +interacting with each other in this case +because there are surfaces are in + + align:start position:0% +because there are surfaces are in + + + align:start position:0% +because there are surfaces are in +contact with each other one sitting on + + align:start position:0% +contact with each other one sitting on + + + align:start position:0% +contact with each other one sitting on +top of the other and the interaction + + align:start position:0% +top of the other and the interaction + + + align:start position:0% +top of the other and the interaction +between the two objects gives rise to a + + align:start position:0% +between the two objects gives rise to a + + + align:start position:0% +between the two objects gives rise to a +pair of forces I have one force that's + + align:start position:0% +pair of forces I have one force that's + + + align:start position:0% +pair of forces I have one force that's +acting from object two down on object + + align:start position:0% +acting from object two down on object + + + align:start position:0% +acting from object two down on object +one and the other force that's acting + + align:start position:0% +one and the other force that's acting + + + align:start position:0% +one and the other force that's acting +from object one back up onto object two + + align:start position:0% +from object one back up onto object two + + + align:start position:0% +from object one back up onto object two +and these forces following Newton's + + align:start position:0% +and these forces following Newton's + + + align:start position:0% +and these forces following Newton's +third law are equal in magnitude and + + align:start position:0% +third law are equal in magnitude and + + + align:start position:0% +third law are equal in magnitude and +opposite in direction what if we now + + align:start position:0% +opposite in direction what if we now + + + align:start position:0% +opposite in direction what if we now +push these blocks horizontally in + + align:start position:0% +push these blocks horizontally in + + + align:start position:0% +push these blocks horizontally in +opposite directions at their interface + + align:start position:0% +opposite directions at their interface + + + align:start position:0% +opposite directions at their interface +there is a frictional interaction this + + align:start position:0% +there is a frictional interaction this + + + align:start position:0% +there is a frictional interaction this +interaction gives rise to a pair of + + align:start position:0% +interaction gives rise to a pair of + + + align:start position:0% +interaction gives rise to a pair of +frictional forces that are parallel to + + align:start position:0% +frictional forces that are parallel to + + + align:start position:0% +frictional forces that are parallel to +the interface the friction force on the + + align:start position:0% +the interface the friction force on the + + + align:start position:0% +the interface the friction force on the +top block from the bottom block is + + align:start position:0% +top block from the bottom block is + + + align:start position:0% +top block from the bottom block is +opposite and direction but equal in + + align:start position:0% +opposite and direction but equal in + + + align:start position:0% +opposite and direction but equal in +magnitude to the friction from the + + align:start position:0% +magnitude to the friction from the + + + align:start position:0% +magnitude to the friction from the +bottom block due to the top block let's + + align:start position:0% +bottom block due to the top block let's + + + align:start position:0% +bottom block due to the top block let's +look at some of the common + + align:start position:0% +look at some of the common + + + align:start position:0% +look at some of the common +misconceptions about forces first of all + + align:start position:0% +misconceptions about forces first of all + + + align:start position:0% +misconceptions about forces first of all +motion is not a force if I have a block + + align:start position:0% +motion is not a force if I have a block + + + align:start position:0% +motion is not a force if I have a block +that's moving at a constant velocity + + align:start position:0% +that's moving at a constant velocity + + + align:start position:0% +that's moving at a constant velocity +along a frictionless plane then there is + + align:start position:0% +along a frictionless plane then there is + + + align:start position:0% +along a frictionless plane then there is +no horizontal force that's acting on + + align:start position:0% +no horizontal force that's acting on + + + align:start position:0% +no horizontal force that's acting on +this block because there is no + + align:start position:0% +this block because there is no + + + align:start position:0% +this block because there is no +interaction that would give rise to a + + align:start position:0% +interaction that would give rise to a + + + align:start position:0% +interaction that would give rise to a +horizontal force the fact that it has a + + align:start position:0% +horizontal force the fact that it has a + + + align:start position:0% +horizontal force the fact that it has a +velocity does not necessarily mean that + + align:start position:0% +velocity does not necessarily mean that + + + align:start position:0% +velocity does not necessarily mean that +there is a force acting on it another + + align:start position:0% +there is a force acting on it another + + + align:start position:0% +there is a force acting on it another +common mistake is to think that forces + + align:start position:0% +common mistake is to think that forces + + + align:start position:0% +common mistake is to think that forces +transfer through objects for example if + + align:start position:0% +transfer through objects for example if + + + align:start position:0% +transfer through objects for example if +I'm pushing a book against a wall it + + align:start position:0% +I'm pushing a book against a wall it + + + align:start position:0% +I'm pushing a book against a wall it +might seem like the force from my hand + + align:start position:0% +might seem like the force from my hand + + + align:start position:0% +might seem like the force from my hand +is being transferred to the wall but + + align:start position:0% +is being transferred to the wall but + + + align:start position:0% +is being transferred to the wall but +what is really happening is that there + + align:start position:0% +what is really happening is that there + + + align:start position:0% +what is really happening is that there +are two independent interactions the + + align:start position:0% +are two independent interactions the + + + align:start position:0% +are two independent interactions the +interaction of my hand with the book and + + align:start position:0% +interaction of my hand with the book and + + + align:start position:0% +interaction of my hand with the book and +the interaction of the book with the + + align:start position:0% +the interaction of the book with the + + + align:start position:0% +the interaction of the book with the +wall and these are separate interactions + + align:start position:0% +wall and these are separate interactions + + + align:start position:0% +wall and these are separate interactions +the forces might happen to have the same + + align:start position:0% +the forces might happen to have the same + + + align:start position:0% +the forces might happen to have the same +magnitude in some cases but it's not + + align:start position:0% +magnitude in some cases but it's not + + + align:start position:0% +magnitude in some cases but it's not +because the force from my hand is being + + align:start position:0% +because the force from my hand is being + + + align:start position:0% +because the force from my hand is being +transferred forces arise between pairs + + align:start position:0% +transferred forces arise between pairs + + + align:start position:0% +transferred forces arise between pairs +of objects and those horses can only act + + align:start position:0% +of objects and those horses can only act + + + align:start position:0% +of objects and those horses can only act +on those two objects + + align:start position:0% + + + + align:start position:0% + +let's look more closely at Newton's + + align:start position:0% +let's look more closely at Newton's + + + align:start position:0% +let's look more closely at Newton's +third law so Newton's third law says + + align:start position:0% +third law so Newton's third law says + + + align:start position:0% +third law so Newton's third law says +that when there are two objects that are + + align:start position:0% +that when there are two objects that are + + + align:start position:0% +that when there are two objects that are +interacting there will be two forces + + align:start position:0% +interacting there will be two forces + + + align:start position:0% +interacting there will be two forces +that arise from that interaction and + + align:start position:0% +that arise from that interaction and + + + align:start position:0% +that arise from that interaction and +these two forces are always equal in + + align:start position:0% +these two forces are always equal in + + + align:start position:0% +these two forces are always equal in +magnitude and opposite in direction + + align:start position:0% +magnitude and opposite in direction + + + align:start position:0% +magnitude and opposite in direction +these two forces this Newton's third law + + align:start position:0% +these two forces this Newton's third law + + + align:start position:0% +these two forces this Newton's third law +pair of forces never act on the same + + align:start position:0% +pair of forces never act on the same + + + align:start position:0% +pair of forces never act on the same +object but instead one force acts on the + + align:start position:0% +object but instead one force acts on the + + + align:start position:0% +object but instead one force acts on the +first object and one on the second + + align:start position:0% +first object and one on the second + + + align:start position:0% +first object and one on the second +because these forces arise out of the + + align:start position:0% +because these forces arise out of the + + + align:start position:0% +because these forces arise out of the +same interaction they have to be the + + align:start position:0% +same interaction they have to be the + + + align:start position:0% +same interaction they have to be the +same type of force so they could be + + align:start position:0% +same type of force so they could be + + + align:start position:0% +same type of force so they could be +gravitational forces frictional forces + + align:start position:0% +gravitational forces frictional forces + + + align:start position:0% +gravitational forces frictional forces +normal forces etc let's look at an + + align:start position:0% +normal forces etc let's look at an + + + align:start position:0% +normal forces etc let's look at an +example of a book sitting on a table + + align:start position:0% +example of a book sitting on a table + + + align:start position:0% +example of a book sitting on a table +it's being pulled down by the + + align:start position:0% +it's being pulled down by the + + + align:start position:0% +it's being pulled down by the +gravitational force and it's being held + + align:start position:0% +gravitational force and it's being held + + + align:start position:0% +gravitational force and it's being held +up by the normal force are these two + + align:start position:0% +up by the normal force are these two + + + align:start position:0% +up by the normal force are these two +forces a news third law pair the book is + + align:start position:0% +forces a news third law pair the book is + + + align:start position:0% +forces a news third law pair the book is +not accelerating so these forces are + + align:start position:0% +not accelerating so these forces are + + + align:start position:0% +not accelerating so these forces are +equal in magnitude and opposite in + + align:start position:0% +equal in magnitude and opposite in + + + align:start position:0% +equal in magnitude and opposite in +direction but they cannot be a Newton's + + align:start position:0% +direction but they cannot be a Newton's + + + align:start position:0% +direction but they cannot be a Newton's +third law pair for two different reasons + + align:start position:0% +third law pair for two different reasons + + + align:start position:0% +third law pair for two different reasons +first of all they both act on the same + + align:start position:0% +first of all they both act on the same + + + align:start position:0% +first of all they both act on the same +object the book and second of all they + + align:start position:0% +object the book and second of all they + + + align:start position:0% +object the book and second of all they +arise from different interactions the + + align:start position:0% +arise from different interactions the + + + align:start position:0% +arise from different interactions the +normal force on the book is part of a + + align:start position:0% +normal force on the book is part of a + + + align:start position:0% +normal force on the book is part of a +Newton's third law pair that comes from + + align:start position:0% +Newton's third law pair that comes from + + + align:start position:0% +Newton's third law pair that comes from +the interaction between the book and the + + align:start position:0% +the interaction between the book and the + + + align:start position:0% +the interaction between the book and the +table + + align:start position:0% +table + + + align:start position:0% +table +what's the Newton's third law pair of + + align:start position:0% +what's the Newton's third law pair of + + + align:start position:0% +what's the Newton's third law pair of +the gravitational force on the book well + + align:start position:0% +the gravitational force on the book well + + + align:start position:0% +the gravitational force on the book well +because the gravitational forces arises + + align:start position:0% +because the gravitational forces arises + + + align:start position:0% +because the gravitational forces arises +from the interaction between the book + + align:start position:0% +from the interaction between the book + + + align:start position:0% +from the interaction between the book +and the earth the other force in the + + align:start position:0% +and the earth the other force in the + + + align:start position:0% +and the earth the other force in the +Newton's third law pair is actually the + + align:start position:0% +Newton's third law pair is actually the + + + align:start position:0% +Newton's third law pair is actually the +force that the book exerts on the earth + + align:start position:0% +force that the book exerts on the earth + + + align:start position:0% +force that the book exerts on the earth +you might not think about the book + + align:start position:0% +you might not think about the book + + + align:start position:0% +you might not think about the book +acting on the earth but the force is + + align:start position:0% +acting on the earth but the force is + + + align:start position:0% +acting on the earth but the force is +actually equal and opposite to the + + align:start position:0% +actually equal and opposite to the + + + align:start position:0% +actually equal and opposite to the +Earth's force on the book it's just that + + align:start position:0% +Earth's force on the book it's just that + + + align:start position:0% +Earth's force on the book it's just that +the earth is so much more massive the + + align:start position:0% +the earth is so much more massive the + + + align:start position:0% +the earth is so much more massive the +force has no detectable influence on the + + align:start position:0% +force has no detectable influence on the + + + align:start position:0% +force has no detectable influence on the +Earth's behavior behavior at all \ No newline at end of file diff --git a/u72VF_VDp2k.txt b/u72VF_VDp2k.txt new file mode 100644 index 0000000000000000000000000000000000000000..68025a4ee544406d7729049301a9d2e12fa602fb --- /dev/null +++ b/u72VF_VDp2k.txt @@ -0,0 +1,10259 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT OpenCourseWare continue to + + align:start position:0% +will help MIT OpenCourseWare continue to + + + align:start position:0% +will help MIT OpenCourseWare continue to +offer high quality educational resources + + align:start position:0% +offer high quality educational resources + + + align:start position:0% +offer high quality educational resources +for free + + align:start position:0% +for free + + + align:start position:0% +for free +to make a donation or to view additional + + align:start position:0% +to make a donation or to view additional + + + align:start position:0% +to make a donation or to view additional +materials from hundreds of MIT courses + + align:start position:0% +materials from hundreds of MIT courses + + + align:start position:0% +materials from hundreds of MIT courses +visit MIT opencourseware at ocw.mit.edu + + align:start position:0% + + + + align:start position:0% + +okay shall we begin so on the syllabus + + align:start position:0% +okay shall we begin so on the syllabus + + + align:start position:0% +okay shall we begin so on the syllabus +today's class is supposed to be a review + + align:start position:0% +today's class is supposed to be a review + + + align:start position:0% +today's class is supposed to be a review +for the next quiz and I'm happy to + + align:start position:0% +for the next quiz and I'm happy to + + + align:start position:0% +for the next quiz and I'm happy to +answer any questions you have about the + + align:start position:0% +answer any questions you have about the + + + align:start position:0% +answer any questions you have about the +material or about the quiz to the best + + align:start position:0% +material or about the quiz to the best + + + align:start position:0% +material or about the quiz to the best +of my ability and when we've exhausted + + align:start position:0% +of my ability and when we've exhausted + + + align:start position:0% +of my ability and when we've exhausted +those questions I have some notes on + + align:start position:0% +those questions I have some notes on + + + align:start position:0% +those questions I have some notes on +another method for solving partial + + align:start position:0% +another method for solving partial + + + align:start position:0% +another method for solving partial +differential equations we didn't really + + align:start position:0% +differential equations we didn't really + + + align:start position:0% +differential equations we didn't really +cover in class but I think it's quite + + align:start position:0% +cover in class but I think it's quite + + + align:start position:0% +cover in class but I think it's quite +quite interesting and applicable for + + align:start position:0% +quite interesting and applicable for + + + align:start position:0% +quite interesting and applicable for +chemical engineers in particular because + + align:start position:0% +chemical engineers in particular because + + + align:start position:0% +chemical engineers in particular because +of the classes of problems that we study + + align:start position:0% +of the classes of problems that we study + + + align:start position:0% +of the classes of problems that we study +and then notes on how to construct a + + align:start position:0% +and then notes on how to construct a + + + align:start position:0% +and then notes on how to construct a +simulation of a PDE that follow from + + align:start position:0% +simulation of a PDE that follow from + + + align:start position:0% +simulation of a PDE that follow from +what Professor Green discussed during + + align:start position:0% +what Professor Green discussed during + + + align:start position:0% +what Professor Green discussed during +your last PDE lecture and we'll do do an + + align:start position:0% +your last PDE lecture and we'll do do an + + + align:start position:0% +your last PDE lecture and we'll do do an +example where we actually develop a code + + align:start position:0% +example where we actually develop a code + + + align:start position:0% +example where we actually develop a code +to solve the PDE and maybe refine it so + + align:start position:0% +to solve the PDE and maybe refine it so + + + align:start position:0% +to solve the PDE and maybe refine it so +that it runs more quickly by noticing + + align:start position:0% +that it runs more quickly by noticing + + + align:start position:0% +that it runs more quickly by noticing +certain things about the structure of + + align:start position:0% +certain things about the structure of + + + align:start position:0% +certain things about the structure of +the problem okay I have your your gift + + align:start position:0% +the problem okay I have your your gift + + + align:start position:0% +the problem okay I have your your gift +cards I remembered them + + align:start position:0% +cards I remembered them + + + align:start position:0% +cards I remembered them +so I'll hand those out at the end of + + align:start position:0% +so I'll hand those out at the end of + + + align:start position:0% +so I'll hand those out at the end of +class just in case more people trickle + + align:start position:0% +class just in case more people trickle + + + align:start position:0% +class just in case more people trickle +in but it doesn't look like there's 53 + + align:start position:0% +in but it doesn't look like there's 53 + + + align:start position:0% +in but it doesn't look like there's 53 +people here so maybe the TAS are gonna + + align:start position:0% +people here so maybe the TAS are gonna + + + align:start position:0% +people here so maybe the TAS are gonna +be eating burritos for a while this is + + align:start position:0% +be eating burritos for a while this is + + + align:start position:0% +be eating burritos for a while this is +for me a lot left over we'll see I'll + + align:start position:0% +for me a lot left over we'll see I'll + + + align:start position:0% +for me a lot left over we'll see I'll +hold on to them try to make sure + + align:start position:0% +hold on to them try to make sure + + + align:start position:0% +hold on to them try to make sure +everyone gets their gets their reward + + align:start position:0% +everyone gets their gets their reward + + + align:start position:0% +everyone gets their gets their reward +for responding to the class survey so + + align:start position:0% +for responding to the class survey so + + + align:start position:0% +for responding to the class survey so +let's let's start with questions about + + align:start position:0% +let's let's start with questions about + + + align:start position:0% +let's let's start with questions about +the quiz about the material that we've + + align:start position:0% +the quiz about the material that we've + + + align:start position:0% +the quiz about the material that we've +covered up to this point I'm really + + align:start position:0% +covered up to this point I'm really + + + align:start position:0% +covered up to this point I'm really +gonna leave it to you to point out + + align:start position:0% +gonna leave it to you to point out + + + align:start position:0% +gonna leave it to you to point out +things so you feel like you need help + + align:start position:0% +things so you feel like you need help + + + align:start position:0% +things so you feel like you need help +with you think need to be reviewed I + + align:start position:0% +with you think need to be reviewed I + + + align:start position:0% +with you think need to be reviewed I +know you've had a review session with + + align:start position:0% +know you've had a review session with + + + align:start position:0% +know you've had a review session with +the TAS already maybe that's been + + align:start position:0% +the TAS already maybe that's been + + + align:start position:0% +the TAS already maybe that's been +sufficient okay questions it's up to you + + align:start position:0% +sufficient okay questions it's up to you + + + align:start position:0% +sufficient okay questions it's up to you +yeah + + align:start position:0% + + + + align:start position:0% + +ooh good question so so I'll tell you + + align:start position:0% +ooh good question so so I'll tell you + + + align:start position:0% +ooh good question so so I'll tell you +that I believe the problems on the quiz + + align:start position:0% +that I believe the problems on the quiz + + + align:start position:0% +that I believe the problems on the quiz +this year are motivated by chemical + + align:start position:0% +this year are motivated by chemical + + + align:start position:0% +this year are motivated by chemical +engineering problems okay the reason for + + align:start position:0% +engineering problems okay the reason for + + + align:start position:0% +engineering problems okay the reason for +that is unlike linear algebra problems + + align:start position:0% +that is unlike linear algebra problems + + + align:start position:0% +that is unlike linear algebra problems +or optimization problems those those can + + align:start position:0% +or optimization problems those those can + + + align:start position:0% +or optimization problems those those can +be crafted out of whole cloth but + + align:start position:0% +be crafted out of whole cloth but + + + align:start position:0% +be crafted out of whole cloth but +workable right boundary value problems + + align:start position:0% +workable right boundary value problems + + + align:start position:0% +workable right boundary value problems +workable initial value problems really + + align:start position:0% +workable initial value problems really + + + align:start position:0% +workable initial value problems really +really neat to stem from something + + align:start position:0% +really neat to stem from something + + + align:start position:0% +really neat to stem from something +physical you are not asked to derive + + align:start position:0% +physical you are not asked to derive + + + align:start position:0% +physical you are not asked to derive +anything from your extensive chemical + + align:start position:0% +anything from your extensive chemical + + + align:start position:0% +anything from your extensive chemical +engineering knowledge is not a qualifier + + align:start position:0% +engineering knowledge is not a qualifier + + + align:start position:0% +engineering knowledge is not a qualifier +for reactors or thermo or transport we + + align:start position:0% +for reactors or thermo or transport we + + + align:start position:0% +for reactors or thermo or transport we +provide you with those details okay but + + align:start position:0% +provide you with those details okay but + + + align:start position:0% +provide you with those details okay but +they are I think they they are of a + + align:start position:0% +they are I think they they are of a + + + align:start position:0% +they are I think they they are of a +chemical engineering origin so you have + + align:start position:0% +chemical engineering origin so you have + + + align:start position:0% +chemical engineering origin so you have +equations that are reasonable to work + + align:start position:0% +equations that are reasonable to work + + + align:start position:0% +equations that are reasonable to work +with okay more questions yes okay sure + + align:start position:0% +with okay more questions yes okay sure + + + align:start position:0% +with okay more questions yes okay sure +so okay so let's let's let's just + + align:start position:0% +so okay so let's let's let's just + + + align:start position:0% +so okay so let's let's let's just +discuss boundary value problems first + + align:start position:0% +discuss boundary value problems first + + + align:start position:0% +discuss boundary value problems first +turns out PDEs are a class of boundary + + align:start position:0% +turns out PDEs are a class of boundary + + + align:start position:0% +turns out PDEs are a class of boundary +value problem to largely at least the + + align:start position:0% +value problem to largely at least the + + + align:start position:0% +value problem to largely at least the +ones that chemical engineers are + + align:start position:0% +ones that chemical engineers are + + + align:start position:0% +ones that chemical engineers are +interested in so if we understand + + align:start position:0% +interested in so if we understand + + + align:start position:0% +interested in so if we understand +boundary value problems in general we + + align:start position:0% +boundary value problems in general we + + + align:start position:0% +boundary value problems in general we +should understand how to solve partial + + align:start position:0% +should understand how to solve partial + + + align:start position:0% +should understand how to solve partial +differential equations to many classes + + align:start position:0% +differential equations to many classes + + + align:start position:0% +differential equations to many classes +of partial differential equations that + + align:start position:0% +of partial differential equations that + + + align:start position:0% +of partial differential equations that +we're interested in can also be solved + + align:start position:0% +we're interested in can also be solved + + + align:start position:0% +we're interested in can also be solved +in these ways so we talked about + + align:start position:0% +in these ways so we talked about + + + align:start position:0% +in these ways so we talked about +relaxation methods in general okay which + + align:start position:0% +relaxation methods in general okay which + + + align:start position:0% +relaxation methods in general okay which +were these methods that rely on somehow + + align:start position:0% +were these methods that rely on somehow + + + align:start position:0% +were these methods that rely on somehow +disk utilizing the continuous function + + align:start position:0% +disk utilizing the continuous function + + + align:start position:0% +disk utilizing the continuous function +that we're trying to describe in this + + align:start position:0% +that we're trying to describe in this + + + align:start position:0% +that we're trying to describe in this +boundary value problem so usually you've + + align:start position:0% +boundary value problem so usually you've + + + align:start position:0% +boundary value problem so usually you've +got some we've got some linear function + + align:start position:0% +got some we've got some linear function + + + align:start position:0% +got some we've got some linear function +okay some linear operator that operates + + align:start position:0% +okay some linear operator that operates + + + align:start position:0% +okay some linear operator that operates +on some variable that we're trying to + + align:start position:0% +on some variable that we're trying to + + + align:start position:0% +on some variable that we're trying to +understand and evaluate boundary value + + align:start position:0% +understand and evaluate boundary value + + + align:start position:0% +understand and evaluate boundary value +from maybe it's temperature right equals + + align:start position:0% +from maybe it's temperature right equals + + + align:start position:0% +from maybe it's temperature right equals +zero so this would be something like + + align:start position:0% +zero so this would be something like + + + align:start position:0% +zero so this would be something like +write thermal diffusion range this + + align:start position:0% +write thermal diffusion range this + + + align:start position:0% +write thermal diffusion range this +equation could represent that could + + align:start position:0% +equation could represent that could + + + align:start position:0% +equation could represent that could +represent some advection diffusion + + align:start position:0% +represent some advection diffusion + + + align:start position:0% +represent some advection diffusion +problem in some bounded domain it can be + + align:start position:0% +problem in some bounded domain it can be + + + align:start position:0% +problem in some bounded domain it can be +a PDE it could be a it could just be a + + align:start position:0% +a PDE it could be a it could just be a + + + align:start position:0% +a PDE it could be a it could just be a +an ordinary differential equation right + + align:start position:0% +an ordinary differential equation right + + + align:start position:0% +an ordinary differential equation right +but a boundary value problem and with + + align:start position:0% +but a boundary value problem and with + + + align:start position:0% +but a boundary value problem and with +this relaxation with these class of + + align:start position:0% +this relaxation with these class of + + + align:start position:0% +this relaxation with these class of +relaxation methods we try not to exactly + + align:start position:0% +relaxation methods we try not to exactly + + + align:start position:0% +relaxation methods we try not to exactly +satisfy this equation we relax that + + align:start position:0% +satisfy this equation we relax that + + + align:start position:0% +satisfy this equation we relax that +assumption we try to somehow discretize + + align:start position:0% +assumption we try to somehow discretize + + + align:start position:0% +assumption we try to somehow discretize +this function could be temperature could + + align:start position:0% +this function could be temperature could + + + align:start position:0% +this function could be temperature could +be energy could be velocity or momentum + + align:start position:0% +be energy could be velocity or momentum + + + align:start position:0% +be energy could be velocity or momentum +be lots of different things try to relax + + align:start position:0% +be lots of different things try to relax + + + align:start position:0% +be lots of different things try to relax +the constraint this is satisfied + + align:start position:0% +the constraint this is satisfied + + + align:start position:0% +the constraint this is satisfied +everywhere and we try to satisfy in some + + align:start position:0% +everywhere and we try to satisfy in some + + + align:start position:0% +everywhere and we try to satisfy in some +approximate sense instead so we + + align:start position:0% +approximate sense instead so we + + + align:start position:0% +approximate sense instead so we +discussed collocation methods where we + + align:start position:0% +discussed collocation methods where we + + + align:start position:0% +discussed collocation methods where we +take the domain we're interested in then + + align:start position:0% +take the domain we're interested in then + + + align:start position:0% +take the domain we're interested in then +we divide it up into a series of points + + align:start position:0% +we divide it up into a series of points + + + align:start position:0% +we divide it up into a series of points +ok and we try to satisfy this equation + + align:start position:0% +ok and we try to satisfy this equation + + + align:start position:0% +ok and we try to satisfy this equation +at those points and we have some + + align:start position:0% +at those points and we have some + + + align:start position:0% +at those points and we have some +approximation for the function its + + align:start position:0% +approximation for the function its + + + align:start position:0% +approximation for the function its +representation at those points that + + align:start position:0% +representation at those points that + + + align:start position:0% +representation at those points that +approximation could be a finite + + align:start position:0% +approximation could be a finite + + + align:start position:0% +approximation could be a finite +difference approximation okay that + + align:start position:0% +difference approximation okay that + + + align:start position:0% +difference approximation okay that +approximation could be a basis set + + align:start position:0% +approximation could be a basis set + + + align:start position:0% +approximation could be a basis set +expansion it could be a finite volume + + align:start position:0% +expansion it could be a finite volume + + + align:start position:0% +expansion it could be a finite volume +approximation we could expand in terms + + align:start position:0% +approximation we could expand in terms + + + align:start position:0% +approximation we could expand in terms +of local basis functions + + align:start position:0% +of local basis functions + + + align:start position:0% +of local basis functions +that's the finite element method we + + align:start position:0% +that's the finite element method we + + + align:start position:0% +that's the finite element method we +covered all these different methods that + + align:start position:0% +covered all these different methods that + + + align:start position:0% +covered all these different methods that +involves chopping the domain up into a + + align:start position:0% +involves chopping the domain up into a + + + align:start position:0% +involves chopping the domain up into a +series of points and trying to satisfy + + align:start position:0% +series of points and trying to satisfy + + + align:start position:0% +series of points and trying to satisfy +the function at each of those points + + align:start position:0% +the function at each of those points + + + align:start position:0% +the function at each of those points +okay + + align:start position:0% +okay + + + align:start position:0% +okay +there was an alternative method right + + align:start position:0% +there was an alternative method right + + + align:start position:0% +there was an alternative method right +this sort of glurk in method where + + align:start position:0% +this sort of glurk in method where + + + align:start position:0% +this sort of glurk in method where +instead of trying to satisfy the + + align:start position:0% +instead of trying to satisfy the + + + align:start position:0% +instead of trying to satisfy the +function at each of those points we have + + align:start position:0% +function at each of those points we have + + + align:start position:0% +function at each of those points we have +some basis set expansion okay so we have + + align:start position:0% +some basis set expansion okay so we have + + + align:start position:0% +some basis set expansion okay so we have +some approximate representation of our + + align:start position:0% +some approximate representation of our + + + align:start position:0% +some approximate representation of our +function in terms of these basis sets in + + align:start position:0% +function in terms of these basis sets in + + + align:start position:0% +function in terms of these basis sets in +terms of this basis set and instead we + + align:start position:0% +terms of this basis set and instead we + + + align:start position:0% +terms of this basis set and instead we +try to make it be the case that the + + align:start position:0% +try to make it be the case that the + + + align:start position:0% +try to make it be the case that the +integral okay of our operator applied to + + align:start position:0% +integral okay of our operator applied to + + + align:start position:0% +integral okay of our operator applied to +our approximation brake chalk multiplied + + align:start position:0% +our approximation brake chalk multiplied + + + align:start position:0% +our approximation brake chalk multiplied +by each of the basis functions and then + + align:start position:0% +by each of the basis functions and then + + + align:start position:0% +by each of the basis functions and then +integrated over this entire domain okay + + align:start position:0% +integrated over this entire domain okay + + + align:start position:0% +integrated over this entire domain okay +is equal to zero okay so we try to + + align:start position:0% +is equal to zero okay so we try to + + + align:start position:0% +is equal to zero okay so we try to +satisfy this equation right with respect + + align:start position:0% +satisfy this equation right with respect + + + align:start position:0% +satisfy this equation right with respect +to each of these basis functions + + align:start position:0% +to each of these basis functions + + + align:start position:0% +to each of these basis functions +essentially right there's some this + + align:start position:0% +essentially right there's some this + + + align:start position:0% +essentially right there's some this +isn't going to exactly satisfy the + + align:start position:0% +isn't going to exactly satisfy the + + + align:start position:0% +isn't going to exactly satisfy the +equation + + align:start position:0% +equation + + + align:start position:0% +equation +this is an approximation so I can + + align:start position:0% +this is an approximation so I can + + + align:start position:0% +this is an approximation so I can +exactly satisfy the boundary value + + align:start position:0% +exactly satisfy the boundary value + + + align:start position:0% +exactly satisfy the boundary value +problem we were after okay but the + + align:start position:0% +problem we were after okay but the + + + align:start position:0% +problem we were after okay but the +projection of the residual or how far + + align:start position:0% +projection of the residual or how far + + + align:start position:0% +projection of the residual or how far +off we are with this operator on each of + + align:start position:0% +off we are with this operator on each of + + + align:start position:0% +off we are with this operator on each of +the basis functions we're gonna try to + + align:start position:0% +the basis functions we're gonna try to + + + align:start position:0% +the basis functions we're gonna try to +force to be zero so rather than trying + + align:start position:0% +force to be zero so rather than trying + + + align:start position:0% +force to be zero so rather than trying +to get a point wise solution of the + + align:start position:0% +to get a point wise solution of the + + + align:start position:0% +to get a point wise solution of the +problem we're gonna try to sort of + + align:start position:0% +problem we're gonna try to sort of + + + align:start position:0% +problem we're gonna try to sort of +smooth out the air with respect to the + + align:start position:0% +smooth out the air with respect to the + + + align:start position:0% +smooth out the air with respect to the +basis functions and make it make this + + align:start position:0% +basis functions and make it make this + + + align:start position:0% +basis functions and make it make this +equation as satisfied as it possibly can + + align:start position:0% +equation as satisfied as it possibly can + + + align:start position:0% +equation as satisfied as it possibly can +with respect to these basis functions + + align:start position:0% +with respect to these basis functions + + + align:start position:0% +with respect to these basis functions +and that's the that's the glurk and view + + align:start position:0% +and that's the that's the glurk and view + + + align:start position:0% +and that's the that's the glurk and view +okay so it's different it's like a + + align:start position:0% +okay so it's different it's like a + + + align:start position:0% +okay so it's different it's like a +you're trying to minimize sort of a + + align:start position:0% +you're trying to minimize sort of a + + + align:start position:0% +you're trying to minimize sort of a +global air with respect to the basis + + align:start position:0% +global air with respect to the basis + + + align:start position:0% +global air with respect to the basis +functions as what as opposed to a point + + align:start position:0% +functions as what as opposed to a point + + + align:start position:0% +functions as what as opposed to a point +wise air okay and again these these + + align:start position:0% +wise air okay and again these these + + + align:start position:0% +wise air okay and again these these +basis functions can be chosen in a lot + + align:start position:0% +basis functions can be chosen in a lot + + + align:start position:0% +basis functions can be chosen in a lot +of different ways they can be chosen as + + align:start position:0% +of different ways they can be chosen as + + + align:start position:0% +of different ways they can be chosen as +sort of global functions they could be + + align:start position:0% +sort of global functions they could be + + + align:start position:0% +sort of global functions they could be +things like sines and cosines right we + + align:start position:0% +things like sines and cosines right we + + + align:start position:0% +things like sines and cosines right we +may know that the solution to this + + align:start position:0% +may know that the solution to this + + + align:start position:0% +may know that the solution to this +equation looks a lot like sines and + + align:start position:0% +equation looks a lot like sines and + + + align:start position:0% +equation looks a lot like sines and +cosines so that makes sense or we may + + align:start position:0% +cosines so that makes sense or we may + + + align:start position:0% +cosines so that makes sense or we may +choose local basis functions and set + + align:start position:0% +choose local basis functions and set + + + align:start position:0% +choose local basis functions and set +little tent functions in 1d okay + + align:start position:0% +little tent functions in 1d okay + + + align:start position:0% +little tent functions in 1d okay +actually tent functions in many + + align:start position:0% +actually tent functions in many + + + align:start position:0% +actually tent functions in many +dimensions as well you can imagine sort + + align:start position:0% +dimensions as well you can imagine sort + + + align:start position:0% +dimensions as well you can imagine sort +of extending that to look like a tent in + + align:start position:0% +of extending that to look like a tent in + + + align:start position:0% +of extending that to look like a tent in +many dimensions that's the finite + + align:start position:0% +many dimensions that's the finite + + + align:start position:0% +many dimensions that's the finite +element method okay so we can choose + + align:start position:0% +element method okay so we can choose + + + align:start position:0% +element method okay so we can choose +those basis functions however we want + + align:start position:0% +those basis functions however we want + + + align:start position:0% +those basis functions however we want +and the goal is to just minimize write + + align:start position:0% +and the goal is to just minimize write + + + align:start position:0% +and the goal is to just minimize write +this residual with respect to each of + + align:start position:0% +this residual with respect to each of + + + align:start position:0% +this residual with respect to each of +the basis functions that we include in + + align:start position:0% +the basis functions that we include in + + + align:start position:0% +the basis functions that we include in +our approximate solution we would call + + align:start position:0% +our approximate solution we would call + + + align:start position:0% +our approximate solution we would call +that a reasonable approximation + + align:start position:0% +that a reasonable approximation + + + align:start position:0% +that a reasonable approximation +presumably as the number of basis + + align:start position:0% +presumably as the number of basis + + + align:start position:0% +presumably as the number of basis +functions goes to infinity this is going + + align:start position:0% +functions goes to infinity this is going + + + align:start position:0% +functions goes to infinity this is going +to converge right that's the applied + + align:start position:0% +to converge right that's the applied + + + align:start position:0% +to converge right that's the applied +mathematicians job to show us that it's + + align:start position:0% +mathematicians job to show us that it's + + + align:start position:0% +mathematicians job to show us that it's +going to converge to the true solution + + align:start position:0% +going to converge to the true solution + + + align:start position:0% +going to converge to the true solution +of the equations okay so those are those + + align:start position:0% +of the equations okay so those are those + + + align:start position:0% +of the equations okay so those are those +those are the methods that we those are + + align:start position:0% +those are the methods that we those are + + + align:start position:0% +those are the methods that we those are +the methods that we apply right good + + align:start position:0% +the methods that we apply right good + + + align:start position:0% +the methods that we apply right good +choice is a basis function are important + + align:start position:0% +choice is a basis function are important + + + align:start position:0% +choice is a basis function are important +so there was a discussion about sort of + + align:start position:0% +so there was a discussion about sort of + + + align:start position:0% +so there was a discussion about sort of +quantum chemistry where you're trying to + + align:start position:0% +quantum chemistry where you're trying to + + + align:start position:0% +quantum chemistry where you're trying to +solve the you're trying to solve the + + align:start position:0% +solve the you're trying to solve the + + + align:start position:0% +solve the you're trying to solve the +Schrodinger equation for n electrons + + align:start position:0% +Schrodinger equation for n electrons + + + align:start position:0% +Schrodinger equation for n electrons +there's three n degrees of freedom so + + align:start position:0% +there's three n degrees of freedom so + + + align:start position:0% +there's three n degrees of freedom so +it's a very high dimensional space + + align:start position:0% +it's a very high dimensional space + + + align:start position:0% +it's a very high dimensional space +how you going to do that you do with + + align:start position:0% +how you going to do that you do with + + + align:start position:0% +how you going to do that you do with +basis set expansions and the choice of + + align:start position:0% +basis set expansions and the choice of + + + align:start position:0% +basis set expansions and the choice of +those basis functions is really + + align:start position:0% +those basis functions is really + + + align:start position:0% +those basis functions is really +important so when you if you read a + + align:start position:0% +important so when you if you read a + + + align:start position:0% +important so when you if you read a +quantum chemistry paper you'll see they + + align:start position:0% +quantum chemistry paper you'll see they + + + align:start position:0% +quantum chemistry paper you'll see they +give a they have a long series of digits + + align:start position:0% +give a they have a long series of digits + + + align:start position:0% +give a they have a long series of digits +and numbers that are meant to indicate + + align:start position:0% +and numbers that are meant to indicate + + + align:start position:0% +and numbers that are meant to indicate +which which basis set expansion they + + align:start position:0% +which which basis set expansion they + + + align:start position:0% +which which basis set expansion they +used and for certain classes a problem + + align:start position:0% +used and for certain classes a problem + + + align:start position:0% +used and for certain classes a problem +some are better than others and they + + align:start position:0% +some are better than others and they + + + align:start position:0% +some are better than others and they +make the + + align:start position:0% +make the + + + align:start position:0% +make the +the problem actually solvable when it's + + align:start position:0% +the problem actually solvable when it's + + + align:start position:0% +the problem actually solvable when it's +when it's not if you were to just choose + + align:start position:0% +when it's not if you were to just choose + + + align:start position:0% +when it's not if you were to just choose +your basis functions you know with + + align:start position:0% +your basis functions you know with + + + align:start position:0% +your basis functions you know with +without care for the physics of the + + align:start position:0% +without care for the physics of the + + + align:start position:0% +without care for the physics of the +problem Sam yeah right well it should + + align:start position:0% +problem Sam yeah right well it should + + + align:start position:0% +problem Sam yeah right well it should +have been right here okay so technically + + align:start position:0% +have been right here okay so technically + + + align:start position:0% +have been right here okay so technically +the basis functions don't have to be + + align:start position:0% +the basis functions don't have to be + + + align:start position:0% +the basis functions don't have to be +real valued functions they could be + + align:start position:0% +real valued functions they could be + + + align:start position:0% +real valued functions they could be +complex valued functions and then this + + align:start position:0% +complex valued functions and then this + + + align:start position:0% +complex valued functions and then this +is this is in some sense a dot product + + align:start position:0% +is this is in some sense a dot product + + + align:start position:0% +is this is in some sense a dot product +okay an inner product in the space of + + align:start position:0% +okay an inner product in the space of + + + align:start position:0% +okay an inner product in the space of +these basis functions and the proper + + align:start position:0% +these basis functions and the proper + + + align:start position:0% +these basis functions and the proper +form for an inner product when we have + + align:start position:0% +form for an inner product when we have + + + align:start position:0% +form for an inner product when we have +complex valued things is to take the + + align:start position:0% +complex valued things is to take the + + + align:start position:0% +complex valued things is to take the +real part of one and multiply it with + + align:start position:0% +real part of one and multiply it with + + + align:start position:0% +real part of one and multiply it with +the complex part of another right so + + align:start position:0% +the complex part of another right so + + + align:start position:0% +the complex part of another right so +that's should have been great here this + + align:start position:0% +that's should have been great here this + + + align:start position:0% +that's should have been great here this +should be the complex conjugate okay yes + + align:start position:0% + + + + align:start position:0% + +yes yes that's right well in the in the + + align:start position:0% +yes yes that's right well in the in the + + + align:start position:0% +yes yes that's right well in the in the +you know if we have a if we have a an + + align:start position:0% +you know if we have a if we have a an + + + align:start position:0% +you know if we have a if we have a an +expansion of our of the sort of + + align:start position:0% +expansion of our of the sort of + + + align:start position:0% +expansion of our of the sort of +objective that we're trying to calculate + + align:start position:0% +objective that we're trying to calculate + + + align:start position:0% +objective that we're trying to calculate +in terms of those basis functions L is + + align:start position:0% +in terms of those basis functions L is + + + align:start position:0% +in terms of those basis functions L is +the real L right it is what it is this + + align:start position:0% +the real L right it is what it is this + + + align:start position:0% +the real L right it is what it is this +is the model equation to be solved we + + align:start position:0% +is the model equation to be solved we + + + align:start position:0% +is the model equation to be solved we +operate on our approximate solution with + + align:start position:0% +operate on our approximate solution with + + + align:start position:0% +operate on our approximate solution with +the real L in the collocation method + + align:start position:0% +the real L in the collocation method + + + align:start position:0% +the real L in the collocation method +that may be the real L or may be some + + align:start position:0% +that may be the real L or may be some + + + align:start position:0% +that may be the real L or may be some +approximation for L if we do finite + + align:start position:0% +approximation for L if we do finite + + + align:start position:0% +approximation for L if we do finite +differences we're approximating all + + align:start position:0% +differences we're approximating all + + + align:start position:0% +differences we're approximating all +these derivatives okay if we do a basis + + align:start position:0% +these derivatives okay if we do a basis + + + align:start position:0% +these derivatives okay if we do a basis +set expansion and we try to satisfy that + + align:start position:0% +set expansion and we try to satisfy that + + + align:start position:0% +set expansion and we try to satisfy that +at a certain number of points + + align:start position:0% +at a certain number of points + + + align:start position:0% +at a certain number of points +we're not approximating L we're + + align:start position:0% +we're not approximating L we're + + + align:start position:0% +we're not approximating L we're +approximating T instead okay so they're + + align:start position:0% +approximating T instead okay so they're + + + align:start position:0% +approximating T instead okay so they're +a little bit they're a little bit + + align:start position:0% +a little bit they're a little bit + + + align:start position:0% +a little bit they're a little bit +different more questions so it's B VP's + + align:start position:0% +different more questions so it's B VP's + + + align:start position:0% +different more questions so it's B VP's +this picture applies for PDE stew okay + + align:start position:0% +this picture applies for PDE stew okay + + + align:start position:0% +this picture applies for PDE stew okay +so this you know this is the integral + + align:start position:0% +so this you know this is the integral + + + align:start position:0% +so this you know this is the integral +over the domain of interest the domain + + align:start position:0% +over the domain of interest the domain + + + align:start position:0% +over the domain of interest the domain +that's bound + + align:start position:0% +that's bound + + + align:start position:0% +that's bound +did right by our boundary conditions + + align:start position:0% +did right by our boundary conditions + + + align:start position:0% +did right by our boundary conditions +these basis functions don't have to be + + align:start position:0% +these basis functions don't have to be + + + align:start position:0% +these basis functions don't have to be +in one dimension they can be in any + + align:start position:0% +in one dimension they can be in any + + + align:start position:0% +in one dimension they can be in any +number of dimensions we want we just + + align:start position:0% +number of dimensions we want we just + + + align:start position:0% +number of dimensions we want we just +want them to be good basis functions in + + align:start position:0% +want them to be good basis functions in + + + align:start position:0% +want them to be good basis functions in +principle okay so for finite elements + + align:start position:0% +principle okay so for finite elements + + + align:start position:0% +principle okay so for finite elements +you use little tents okay a + + align:start position:0% +you use little tents okay a + + + align:start position:0% +you use little tents okay a +multi-dimensional tents but they're + + align:start position:0% +multi-dimensional tents but they're + + + align:start position:0% +multi-dimensional tents but they're +still tents the same as these have + + align:start position:0% +still tents the same as these have + + + align:start position:0% +still tents the same as these have +functions that Professor Green talked + + align:start position:0% +functions that Professor Green talked + + + align:start position:0% +functions that Professor Green talked +about in 1d just do them in many + + align:start position:0% +about in 1d just do them in many + + + align:start position:0% +about in 1d just do them in many +dimensions okay they work exactly the + + align:start position:0% +dimensions okay they work exactly the + + + align:start position:0% +dimensions okay they work exactly the +same way they're easy to take the + + align:start position:0% +same way they're easy to take the + + + align:start position:0% +same way they're easy to take the +derivatives of these integrals are for + + align:start position:0% +derivatives of these integrals are for + + + align:start position:0% +derivatives of these integrals are for +the most part simple to calculate that's + + align:start position:0% +the most part simple to calculate that's + + + align:start position:0% +the most part simple to calculate that's +that's why COMSOL for example uses uses + + align:start position:0% +that's why COMSOL for example uses uses + + + align:start position:0% +that's why COMSOL for example uses uses +that methodology it's based on this sort + + align:start position:0% +that methodology it's based on this sort + + + align:start position:0% +that methodology it's based on this sort +of glurk in picture so P DS be VPS + + align:start position:0% +of glurk in picture so P DS be VPS + + + align:start position:0% +of glurk in picture so P DS be VPS +look very similar okay usually we're + + align:start position:0% +look very similar okay usually we're + + + align:start position:0% +look very similar okay usually we're +talking about spatial dimensions that + + align:start position:0% +talking about spatial dimensions that + + + align:start position:0% +talking about spatial dimensions that +look very similar when we go to the time + + align:start position:0% +look very similar when we go to the time + + + align:start position:0% +look very similar when we go to the time +domain things get a little more + + align:start position:0% +domain things get a little more + + + align:start position:0% +domain things get a little more +confusing right that mixes together what + + align:start position:0% +confusing right that mixes together what + + + align:start position:0% +confusing right that mixes together what +we know from oti VPS with what we know + + align:start position:0% +we know from oti VPS with what we know + + + align:start position:0% +we know from oti VPS with what we know +from boundary value problems down so you + + align:start position:0% +from boundary value problems down so you + + + align:start position:0% +from boundary value problems down so you +talked about the method of lines last + + align:start position:0% +talked about the method of lines last + + + align:start position:0% +talked about the method of lines last +time is one way of studying for example + + align:start position:0% +time is one way of studying for example + + + align:start position:0% +time is one way of studying for example +parabolic partial differential equations + + align:start position:0% +parabolic partial differential equations + + + align:start position:0% +parabolic partial differential equations +you have the spatial discretization like + + align:start position:0% +you have the spatial discretization like + + + align:start position:0% +you have the spatial discretization like +this and then in time you have some ODI + + align:start position:0% +this and then in time you have some ODI + + + align:start position:0% +this and then in time you have some ODI +VP technique that you integrate forward + + align:start position:0% +VP technique that you integrate forward + + + align:start position:0% +VP technique that you integrate forward +right you rely on these robust OD + + align:start position:0% +right you rely on these robust OD + + + align:start position:0% +right you rely on these robust OD +methods that know how to control the + + align:start position:0% +methods that know how to control the + + + align:start position:0% +methods that know how to control the +numerical air can detect maybe when + + align:start position:0% +numerical air can detect maybe when + + + align:start position:0% +numerical air can detect maybe when +there's some sort of an instability and + + align:start position:0% +there's some sort of an instability and + + + align:start position:0% +there's some sort of an instability and +try to damp it out by altering the time + + align:start position:0% +try to damp it out by altering the time + + + align:start position:0% +try to damp it out by altering the time +step so that things stay stable yes sure + + align:start position:0% +step so that things stay stable yes sure + + + align:start position:0% +step so that things stay stable yes sure +so + + align:start position:0% + + + + align:start position:0% + +so first of all there are a lot of local + + align:start position:0% +so first of all there are a lot of local + + + align:start position:0% +so first of all there are a lot of local +basis functions we could write down okay + + align:start position:0% +basis functions we could write down okay + + + align:start position:0% +basis functions we could write down okay +there are many of them so yes so let's + + align:start position:0% +there are many of them so yes so let's + + + align:start position:0% +there are many of them so yes so let's +do the Hat okay + + align:start position:0% + + + + align:start position:0% + +let's suppose I have this line right in + + align:start position:0% +let's suppose I have this line right in + + + align:start position:0% +let's suppose I have this line right in +X and I target in my collocation method + + align:start position:0% +X and I target in my collocation method + + + align:start position:0% +X and I target in my collocation method +a series of points column X I minus 1 + + align:start position:0% +a series of points column X I minus 1 + + + align:start position:0% +a series of points column X I minus 1 +xixi plus 1 and they extend well beyond + + align:start position:0% +xixi plus 1 and they extend well beyond + + + align:start position:0% +xixi plus 1 and they extend well beyond +here it doesn't matter where they are + + align:start position:0% +here it doesn't matter where they are + + + align:start position:0% +here it doesn't matter where they are +okay I choose where they are based on + + align:start position:0% +okay I choose where they are based on + + + align:start position:0% +okay I choose where they are based on +the physics of the problem I'll put them + + align:start position:0% +the physics of the problem I'll put them + + + align:start position:0% +the physics of the problem I'll put them +where I want them to go and in fact you + + align:start position:0% +where I want them to go and in fact you + + + align:start position:0% +where I want them to go and in fact you +might even try to optimize where they go + + align:start position:0% +might even try to optimize where they go + + + align:start position:0% +might even try to optimize where they go +so you might start with some + + align:start position:0% +so you might start with some + + + align:start position:0% +so you might start with some +distribution of them and then move them + + align:start position:0% +distribution of them and then move them + + + align:start position:0% +distribution of them and then move them +around in some way to improve the + + align:start position:0% +around in some way to improve the + + + align:start position:0% +around in some way to improve the +quality of your solution right maybe you + + align:start position:0% +quality of your solution right maybe you + + + align:start position:0% +quality of your solution right maybe you +maybe you distribute them uniformly + + align:start position:0% +maybe you distribute them uniformly + + + align:start position:0% +maybe you distribute them uniformly +first and then you notice so my solution + + align:start position:0% +first and then you notice so my solution + + + align:start position:0% +first and then you notice so my solution +is changing very quickly over here I + + align:start position:0% +is changing very quickly over here I + + + align:start position:0% +is changing very quickly over here I +would like more points in this region + + align:start position:0% +would like more points in this region + + + align:start position:0% +would like more points in this region +live it in MATLAB there's a function + + align:start position:0% +live it in MATLAB there's a function + + + align:start position:0% +live it in MATLAB there's a function +called be VP for C which is a boundary + + align:start position:0% +called be VP for C which is a boundary + + + align:start position:0% +called be VP for C which is a boundary +value problem solver solves 1d boundary + + align:start position:0% +value problem solver solves 1d boundary + + + align:start position:0% +value problem solver solves 1d boundary +value problems and it does precisely + + align:start position:0% +value problems and it does precisely + + + align:start position:0% +value problems and it does precisely +this uses finite differences in + + align:start position:0% +this uses finite differences in + + + align:start position:0% +this uses finite differences in +collocation and the good thing about it + + align:start position:0% +collocation and the good thing about it + + + align:start position:0% +collocation and the good thing about it +is it's trying to adaptively change + + align:start position:0% +is it's trying to adaptively change + + + align:start position:0% +is it's trying to adaptively change +where these points are positioned so it + + align:start position:0% +where these points are positioned so it + + + align:start position:0% +where these points are positioned so it +solves it + + align:start position:0% +solves it + + + align:start position:0% +solves it +it looks where things are changing + + align:start position:0% +it looks where things are changing + + + align:start position:0% +it looks where things are changing +quickly and tries to shift its shift its + + align:start position:0% +quickly and tries to shift its shift its + + + align:start position:0% +quickly and tries to shift its shift its +points around and Reese all've it right + + align:start position:0% +points around and Reese all've it right + + + align:start position:0% +points around and Reese all've it right +in order to improve the quality of the + + align:start position:0% +in order to improve the quality of the + + + align:start position:0% +in order to improve the quality of the +solution hit certain certain targets for + + align:start position:0% +solution hit certain certain targets for + + + align:start position:0% +solution hit certain certain targets for +the air okay so what do these what would + + align:start position:0% +the air okay so what do these what would + + + align:start position:0% +the air okay so what do these what would +these local basis functions look like so + + align:start position:0% +these local basis functions look like so + + + align:start position:0% +these local basis functions look like so +we talked about these hats right there + + align:start position:0% +we talked about these hats right there + + + align:start position:0% +we talked about these hats right there +one here right they're going to be 0 on + + align:start position:0% +one here right they're going to be 0 on + + + align:start position:0% +one here right they're going to be 0 on +either side at this point we could call + + align:start position:0% +either side at this point we could call + + + align:start position:0% +either side at this point we could call +this our hat I okay which is centered at + + align:start position:0% +this our hat I okay which is centered at + + + align:start position:0% +this our hat I okay which is centered at +point X I and it's going to raise it's + + align:start position:0% +point X I and it's going to raise it's + + + align:start position:0% +point X I and it's going to raise it's +going to be a piecewise sort of function + + align:start position:0% +going to be a piecewise sort of function + + + align:start position:0% +going to be a piecewise sort of function +ok it's going to be an increasing linear + + align:start position:0% +ok it's going to be an increasing linear + + + align:start position:0% +ok it's going to be an increasing linear +function between X I minus 1 and X I so + + align:start position:0% +function between X I minus 1 and X I so + + + align:start position:0% +function between X I minus 1 and X I so +for X between X I and X I minus 1 it'll + + align:start position:0% +for X between X I and X I minus 1 it'll + + + align:start position:0% +for X between X I and X I minus 1 it'll +have one form and it's got a switch it's + + align:start position:0% +have one form and it's got a switch it's + + + align:start position:0% +have one form and it's got a switch it's +going to be a decreasing function on the + + align:start position:0% +going to be a decreasing function on the + + + align:start position:0% +going to be a decreasing function on the +other side so between X I and X I plus 1 + + align:start position:0% +other side so between X I and X I plus 1 + + + align:start position:0% +other side so between X I and X I plus 1 +it'll have a different form so here + + align:start position:0% +it'll have a different form so here + + + align:start position:0% +it'll have a different form so here +right it's going to increase between 0 + + align:start position:0% +right it's going to increase between 0 + + + align:start position:0% +right it's going to increase between 0 +and 1 so it's gonna have to look + + align:start position:0% +and 1 so it's gonna have to look + + + align:start position:0% +and 1 so it's gonna have to look +something like X + + align:start position:0% +something like X + + + align:start position:0% +something like X +- X I minus 1 divided by X I minus X I + + align:start position:0% +- X I minus 1 divided by X I minus X I + + + align:start position:0% +- X I minus 1 divided by X I minus X I +minus 1 okay so it goes from 0 to 1 okay + + align:start position:0% +minus 1 okay so it goes from 0 to 1 okay + + + align:start position:0% +minus 1 okay so it goes from 0 to 1 okay +and then the other side it's gonna have + + align:start position:0% +and then the other side it's gonna have + + + align:start position:0% +and then the other side it's gonna have +to have the opposite sign okay so this + + align:start position:0% +to have the opposite sign okay so this + + + align:start position:0% +to have the opposite sign okay so this +is gonna have to look like let's see X + + align:start position:0% +is gonna have to look like let's see X + + + align:start position:0% +is gonna have to look like let's see X +minus X I plus 1 divided by X I minus X + + align:start position:0% +minus X I plus 1 divided by X I minus X + + + align:start position:0% +minus X I plus 1 divided by X I minus X +I plus 1 well that'd do it + + align:start position:0% +I plus 1 well that'd do it + + + align:start position:0% +I plus 1 well that'd do it +I think so okay you are gonna make it + + align:start position:0% +I think so okay you are gonna make it + + + align:start position:0% +I think so okay you are gonna make it +look like this one so you could do a + + align:start position:0% +look like this one so you could do a + + + align:start position:0% +look like this one so you could do a +plus 1 X I and then put a minus sign in + + align:start position:0% +plus 1 X I and then put a minus sign in + + + align:start position:0% +plus 1 X I and then put a minus sign in +front of it if you want okay + + align:start position:0% +front of it if you want okay + + + align:start position:0% +front of it if you want okay +you decide how you want to write it okay + + align:start position:0% +you decide how you want to write it okay + + + align:start position:0% +you decide how you want to write it okay +but it describes this line here and this + + align:start position:0% +but it describes this line here and this + + + align:start position:0% +but it describes this line here and this +line here but there are other choices + + align:start position:0% +line here but there are other choices + + + align:start position:0% +line here but there are other choices +okay + + align:start position:0% +okay + + + align:start position:0% +okay +this doesn't have to be piecewise linear + + align:start position:0% +this doesn't have to be piecewise linear + + + align:start position:0% +this doesn't have to be piecewise linear +necessarily right a lot of times people + + align:start position:0% +necessarily right a lot of times people + + + align:start position:0% +necessarily right a lot of times people +choose different different types of + + align:start position:0% +choose different different types of + + + align:start position:0% +choose different different types of +splines + + align:start position:0% +splines + + + align:start position:0% +splines +okay different types of interpolating + + align:start position:0% +okay different types of interpolating + + + align:start position:0% +okay different types of interpolating +functions they might not be localized to + + align:start position:0% +functions they might not be localized to + + + align:start position:0% +functions they might not be localized to +one point they might be localized over a + + align:start position:0% +one point they might be localized over a + + + align:start position:0% +one point they might be localized over a +few points okay + + align:start position:0% +few points okay + + + align:start position:0% +few points okay +maybe something about the physics of a + + align:start position:0% +maybe something about the physics of a + + + align:start position:0% +maybe something about the physics of a +particular problem that tell you right + + align:start position:0% +particular problem that tell you right + + + align:start position:0% +particular problem that tell you right +you can't get away with these piecewise + + align:start position:0% +you can't get away with these piecewise + + + align:start position:0% +you can't get away with these piecewise +linear functions that they're not good + + align:start position:0% +linear functions that they're not good + + + align:start position:0% +linear functions that they're not good +enough to describe say higher-order + + align:start position:0% +enough to describe say higher-order + + + align:start position:0% +enough to describe say higher-order +derivatives in your equation okay so you + + align:start position:0% +derivatives in your equation okay so you + + + align:start position:0% +derivatives in your equation okay so you +might instead interpolate with I don't + + align:start position:0% +might instead interpolate with I don't + + + align:start position:0% +might instead interpolate with I don't +know like a quadratic basis function + + align:start position:0% +know like a quadratic basis function + + + align:start position:0% +know like a quadratic basis function +that spans a few more points I'll be + + align:start position:0% +that spans a few more points I'll be + + + align:start position:0% +that spans a few more points I'll be +fine it would be easy to do the + + align:start position:0% +fine it would be easy to do the + + + align:start position:0% +fine it would be easy to do the +integration and your glucan method uses + + align:start position:0% +integration and your glucan method uses + + + align:start position:0% +integration and your glucan method uses +do these integrals out they're + + align:start position:0% +do these integrals out they're + + + align:start position:0% +do these integrals out they're +complicated but you do them do them once + + align:start position:0% +complicated but you do them do them once + + + align:start position:0% +complicated but you do them do them once +for a generic point X I and you know + + align:start position:0% +for a generic point X I and you know + + + align:start position:0% +for a generic point X I and you know +their value for every point in the + + align:start position:0% +their value for every point in the + + + align:start position:0% +their value for every point in the +domain okay so you choose them you + + align:start position:0% +domain okay so you choose them you + + + align:start position:0% +domain okay so you choose them you +choose the basis set okay but that's + + align:start position:0% +choose the basis set okay but that's + + + align:start position:0% +choose the basis set okay but that's +that W mean equation for the tenth + + align:start position:0% +that W mean equation for the tenth + + + align:start position:0% +that W mean equation for the tenth +function centered at X I that's the + + align:start position:0% +function centered at X I that's the + + + align:start position:0% +function centered at X I that's the +tenth function centered at any point in + + align:start position:0% +tenth function centered at any point in + + + align:start position:0% +tenth function centered at any point in +the domain in principle in many + + align:start position:0% +the domain in principle in many + + + align:start position:0% +the domain in principle in many +dimensions right so if I have two + + align:start position:0% +dimensions right so if I have two + + + align:start position:0% +dimensions right so if I have two +dimensions you see in COMSOL right you + + align:start position:0% +dimensions you see in COMSOL right you + + + align:start position:0% +dimensions you see in COMSOL right you +have a sort of a triangular mesh and + + align:start position:0% +have a sort of a triangular mesh and + + + align:start position:0% +have a sort of a triangular mesh and +what does my tenth function do it sort + + align:start position:0% +what does my tenth function do it sort + + + align:start position:0% +what does my tenth function do it sort +of stands up right stands up above the + + align:start position:0% +of stands up right stands up above the + + + align:start position:0% +of stands up right stands up above the +triangle it's a real tenth no it's + + align:start position:0% +triangle it's a real tenth no it's + + + align:start position:0% +triangle it's a real tenth no it's +coming out of the board can you see it + + align:start position:0% +coming out of the board can you see it + + + align:start position:0% +coming out of the board can you see it +put on your 3d glasses you'll see it + + align:start position:0% +put on your 3d glasses you'll see it + + + align:start position:0% +put on your 3d glasses you'll see it +then it's coming out of the board okay + + align:start position:0% +then it's coming out of the board okay + + + align:start position:0% +then it's coming out of the board okay +it has height one above this triangular + + align:start position:0% +it has height one above this triangular + + + align:start position:0% +it has height one above this triangular +domain right it sits at the center of + + align:start position:0% +domain right it sits at the center of + + + align:start position:0% +domain right it sits at the center of +the triangle for exams one way to draw + + align:start position:0% +the triangle for exams one way to draw + + + align:start position:0% +the triangle for exams one way to draw +these elements actually many ways to + + align:start position:0% +these elements actually many ways to + + + align:start position:0% +these elements actually many ways to +draw these offices just one way of + + align:start position:0% +draw these offices just one way of + + + align:start position:0% +draw these offices just one way of +drawing these oh that's okay + + align:start position:0% +drawing these oh that's okay + + + align:start position:0% +drawing these oh that's okay +good other questions + + align:start position:0% +good other questions + + + align:start position:0% +good other questions +oh good question + + align:start position:0% + + + + align:start position:0% + +good question so why is central + + align:start position:0% +good question so why is central + + + align:start position:0% +good question so why is central +differencing second order accurate so + + align:start position:0% +differencing second order accurate so + + + align:start position:0% +differencing second order accurate so +the central difference formula says that + + align:start position:0% +the central difference formula says that + + + align:start position:0% +the central difference formula says that +the derivative of a function X could be + + align:start position:0% +the derivative of a function X could be + + + align:start position:0% +the derivative of a function X could be +written as its f at X I plus 1 minus F + + align:start position:0% +written as its f at X I plus 1 minus F + + + align:start position:0% +written as its f at X I plus 1 minus F +at X I minus 1/2 Delta X or let's say + + align:start position:0% +at X I minus 1/2 Delta X or let's say + + + align:start position:0% +at X I minus 1/2 Delta X or let's say +these aren't equally spaced points well + + align:start position:0% +these aren't equally spaced points well + + + align:start position:0% +these aren't equally spaced points well +let's make these equally spaced points + + align:start position:0% +let's make these equally spaced points + + + align:start position:0% +let's make these equally spaced points +for now let's make it easy okay so let's + + align:start position:0% +for now let's make it easy okay so let's + + + align:start position:0% +for now let's make it easy okay so let's +say X I plus Delta X and X I - day it'll + + align:start position:0% +say X I plus Delta X and X I - day it'll + + + align:start position:0% +say X I plus Delta X and X I - day it'll +make our lives easier if we do it this + + align:start position:0% +make our lives easier if we do it this + + + align:start position:0% +make our lives easier if we do it this +way it can be generalized but let's + + align:start position:0% +way it can be generalized but let's + + + align:start position:0% +way it can be generalized but let's +let's let's do it the easiest possible + + align:start position:0% +let's let's do it the easiest possible + + + align:start position:0% +let's let's do it the easiest possible +way and this is the derivative at the + + align:start position:0% +way and this is the derivative at the + + + align:start position:0% +way and this is the derivative at the +point X I write graphically okay here's + + align:start position:0% +point X I write graphically okay here's + + + align:start position:0% +point X I write graphically okay here's +X here's X I right here's my function + + align:start position:0% +X here's X I right here's my function + + + align:start position:0% +X here's X I right here's my function +okay I want to know what the slope here + + align:start position:0% +okay I want to know what the slope here + + + align:start position:0% +okay I want to know what the slope here +is okay and I'm gonna proximate it by + + align:start position:0% +is okay and I'm gonna proximate it by + + + align:start position:0% +is okay and I'm gonna proximate it by +looking one point upstream and one point + + align:start position:0% +looking one point upstream and one point + + + align:start position:0% +looking one point upstream and one point +downstream okay and I'm gonna connect + + align:start position:0% +downstream okay and I'm gonna connect + + + align:start position:0% +downstream okay and I'm gonna connect +those points with a line you would agree + + align:start position:0% +those points with a line you would agree + + + align:start position:0% +those points with a line you would agree +that is the one as this spacing gets + + align:start position:0% +that is the one as this spacing gets + + + align:start position:0% +that is the one as this spacing gets +smaller and smaller it'll be a good + + align:start position:0% +smaller and smaller it'll be a good + + + align:start position:0% +smaller and smaller it'll be a good +approximation for what the derivative is + + align:start position:0% +approximation for what the derivative is + + + align:start position:0% +approximation for what the derivative is +so why is it second-order accurate so + + align:start position:0% +so why is it second-order accurate so + + + align:start position:0% +so why is it second-order accurate so +you can show that it's not too hard okay + + align:start position:0% +you can show that it's not too hard okay + + + align:start position:0% +you can show that it's not too hard okay +you can show that using Taylor series + + align:start position:0% +you can show that using Taylor series + + + align:start position:0% +you can show that using Taylor series +expansion like everything else in this + + align:start position:0% +expansion like everything else in this + + + align:start position:0% +expansion like everything else in this +course right the Taylor series is really + + align:start position:0% +course right the Taylor series is really + + + align:start position:0% +course right the Taylor series is really +a key so let's let's look at it okay + + align:start position:0% +a key so let's let's look at it okay + + + align:start position:0% +a key so let's let's look at it okay +so f at X I plus Delta X I want to write + + align:start position:0% +so f at X I plus Delta X I want to write + + + align:start position:0% +so f at X I plus Delta X I want to write +this as a Taylor series expansion about + + align:start position:0% +this as a Taylor series expansion about + + + align:start position:0% +this as a Taylor series expansion about +the point X I okay so tell me the first + + align:start position:0% +the point X I okay so tell me the first + + + align:start position:0% +the point X I okay so tell me the first +term f of X I okay tell me the second + + align:start position:0% +term f of X I okay tell me the second + + + align:start position:0% +term f of X I okay tell me the second +term + + align:start position:0% + + + + align:start position:0% + +f Prime at X I times Delta X tell me the + + align:start position:0% +f Prime at X I times Delta X tell me the + + + align:start position:0% +f Prime at X I times Delta X tell me the +third term 1/2 F double Prime at times + + align:start position:0% +third term 1/2 F double Prime at times + + + align:start position:0% +third term 1/2 F double Prime at times +how big is the third term okay this is + + align:start position:0% +how big is the third term okay this is + + + align:start position:0% +how big is the third term okay this is +always true by the way this not always + + align:start position:0% +always true by the way this not always + + + align:start position:0% +always true by the way this not always +right there are lots of functions non + + align:start position:0% +right there are lots of functions non + + + align:start position:0% +right there are lots of functions non +analytic functions that don't have these + + align:start position:0% +analytic functions that don't have these + + + align:start position:0% +analytic functions that don't have these +sorts of expansions so we're sort of we + + align:start position:0% +sorts of expansions so we're sort of we + + + align:start position:0% +sorts of expansions so we're sort of we +got to have a function that has these + + align:start position:0% +got to have a function that has these + + + align:start position:0% +got to have a function that has these +derivatives they need to exist at the + + align:start position:0% +derivatives they need to exist at the + + + align:start position:0% +derivatives they need to exist at the +point X I let's assume that's true + + align:start position:0% +point X I let's assume that's true + + + align:start position:0% +point X I let's assume that's true +ok good ok now I'm going to do something + + align:start position:0% +ok good ok now I'm going to do something + + + align:start position:0% +ok good ok now I'm going to do something +really simple let's let's write F at X X + + align:start position:0% +really simple let's let's write F at X X + + + align:start position:0% +really simple let's let's write F at X X +I'm minus Delta X ok and let's just + + align:start position:0% +I'm minus Delta X ok and let's just + + + align:start position:0% +I'm minus Delta X ok and let's just +point out the differences between these + + align:start position:0% +point out the differences between these + + + align:start position:0% +point out the differences between these +two formulas ok so this is the same ok + + align:start position:0% +two formulas ok so this is the same ok + + + align:start position:0% +two formulas ok so this is the same ok +this switches sign because Delta X which + + align:start position:0% +this switches sign because Delta X which + + + align:start position:0% +this switches sign because Delta X which +signs was plus Delta X now it's minus + + align:start position:0% +signs was plus Delta X now it's minus + + + align:start position:0% +signs was plus Delta X now it's minus +Delta X ok this is the same Delta x + + align:start position:0% +Delta X ok this is the same Delta x + + + align:start position:0% +Delta X ok this is the same Delta x +squared same as minus Delta x squared + + align:start position:0% +squared same as minus Delta x squared + + + align:start position:0% +squared same as minus Delta x squared +doesn't matter ok this one down here + + align:start position:0% +doesn't matter ok this one down here + + + align:start position:0% +doesn't matter ok this one down here +well ok its order Delta X cubed ok it'll + + align:start position:0% +well ok its order Delta X cubed ok it'll + + + align:start position:0% +well ok its order Delta X cubed ok it'll +actually look the same but have the + + align:start position:0% +actually look the same but have the + + + align:start position:0% +actually look the same but have the +opposite sign ok we can't resolve it + + align:start position:0% +opposite sign ok we can't resolve it + + + align:start position:0% +opposite sign ok we can't resolve it +though that's sort of the tricky part + + align:start position:0% +though that's sort of the tricky part + + + align:start position:0% +though that's sort of the tricky part +right + + align:start position:0% +right + + + align:start position:0% +right +we don't know ok we don't know for sure + + align:start position:0% +we don't know ok we don't know for sure + + + align:start position:0% +we don't know ok we don't know for sure +what value that takes on this just gives + + align:start position:0% +what value that takes on this just gives + + + align:start position:0% +what value that takes on this just gives +us a bound for how big the air is in + + align:start position:0% +us a bound for how big the air is in + + + align:start position:0% +us a bound for how big the air is in +this expansion + + align:start position:0% + + + + align:start position:0% + +so let's now compute what's in that + + align:start position:0% +so let's now compute what's in that + + + align:start position:0% +so let's now compute what's in that +formula so if we take the difference + + align:start position:0% +formula so if we take the difference + + + align:start position:0% +formula so if we take the difference +between this and this ok these two will + + align:start position:0% +between this and this ok these two will + + + align:start position:0% +between this and this ok these two will +cancel ok these two will combine I'll + + align:start position:0% +cancel ok these two will combine I'll + + + align:start position:0% +cancel ok these two will combine I'll +get to F prime X I times Delta X these + + align:start position:0% +get to F prime X I times Delta X these + + + align:start position:0% +get to F prime X I times Delta X these +two will cancel ok so I'll get 0 + + align:start position:0% +two will cancel ok so I'll get 0 + + + align:start position:0% +two will cancel ok so I'll get 0 +these two okay I can't rely on them + + align:start position:0% +these two okay I can't rely on them + + + align:start position:0% +these two okay I can't rely on them +necessarily necessarily cancelling each + + align:start position:0% +necessarily necessarily cancelling each + + + align:start position:0% +necessarily necessarily cancelling each +other out in fact they want to combine + + align:start position:0% +other out in fact they want to combine + + + align:start position:0% +other out in fact they want to combine +in principle right we've just bounded + + align:start position:0% +in principle right we've just bounded + + + align:start position:0% +in principle right we've just bounded +the air here we don't really know what + + align:start position:0% +the air here we don't really know what + + + align:start position:0% +the air here we don't really know what +it is but it gives me something that's + + align:start position:0% +it is but it gives me something that's + + + align:start position:0% +it is but it gives me something that's +order Delta X cubed in size okay so this + + align:start position:0% +order Delta X cubed in size okay so this + + + align:start position:0% +order Delta X cubed in size okay so this +is the this is one minus one minus two + + align:start position:0% +is the this is one minus one minus two + + + align:start position:0% +is the this is one minus one minus two +okay + + align:start position:0% +okay + + + align:start position:0% +okay +it's two F prime X I times Delta X plus + + align:start position:0% +it's two F prime X I times Delta X plus + + + align:start position:0% +it's two F prime X I times Delta X plus +the air which is order Delta X cubed if + + align:start position:0% +the air which is order Delta X cubed if + + + align:start position:0% +the air which is order Delta X cubed if +I divide by two Delta X ok I know you + + align:start position:0% +I divide by two Delta X ok I know you + + + align:start position:0% +I divide by two Delta X ok I know you +guys hate it when the instructor does + + align:start position:0% +guys hate it when the instructor does + + + align:start position:0% +guys hate it when the instructor does +this but you know you can't can't help + + align:start position:0% +this but you know you can't can't help + + + align:start position:0% +this but you know you can't can't help +it divided by Delta X the error becomes + + align:start position:0% +it divided by Delta X the error becomes + + + align:start position:0% +it divided by Delta X the error becomes +order Delta x squared okay so have the + + align:start position:0% +order Delta x squared okay so have the + + + align:start position:0% +order Delta x squared okay so have the +derivative is this thing plus some order + + align:start position:0% +derivative is this thing plus some order + + + align:start position:0% +derivative is this thing plus some order +Delta x squared peace its second order + + align:start position:0% +Delta x squared peace its second order + + + align:start position:0% +Delta x squared peace its second order +accurate we would say great the air is + + align:start position:0% +accurate we would say great the air is + + + align:start position:0% +accurate we would say great the air is +going to be reduced like the square of + + align:start position:0% +going to be reduced like the square of + + + align:start position:0% +going to be reduced like the square of +the spacing now you can imagine all the + + align:start position:0% +the spacing now you can imagine all the + + + align:start position:0% +the spacing now you can imagine all the +finite difference formulas out there in + + align:start position:0% +finite difference formulas out there in + + + align:start position:0% +finite difference formulas out there in +the world are constructed in this way + + align:start position:0% +the world are constructed in this way + + + align:start position:0% +the world are constructed in this way +right you use Taylor series expansions + + align:start position:0% +right you use Taylor series expansions + + + align:start position:0% +right you use Taylor series expansions +you got as many terms as you need to go + + align:start position:0% +you got as many terms as you need to go + + + align:start position:0% +you got as many terms as you need to go +for the level of accuracy you're trying + + align:start position:0% +for the level of accuracy you're trying + + + align:start position:0% +for the level of accuracy you're trying +to achieve for different points spaced + + align:start position:0% +to achieve for different points spaced + + + align:start position:0% +to achieve for different points spaced +in different ways and you you try to try + + align:start position:0% +in different ways and you you try to try + + + align:start position:0% +in different ways and you you try to try +to dream up some linear combination of + + align:start position:0% +to dream up some linear combination of + + + align:start position:0% +to dream up some linear combination of +these things so that you get a certain + + align:start position:0% +these things so that you get a certain + + + align:start position:0% +these things so that you get a certain +certain level of accuracy okay they're + + align:start position:0% +certain level of accuracy okay they're + + + align:start position:0% +certain level of accuracy okay they're +also not unique right I can construct + + align:start position:0% +also not unique right I can construct + + + align:start position:0% +also not unique right I can construct +these in a lot of different ways okay + + align:start position:0% +these in a lot of different ways okay + + + align:start position:0% +these in a lot of different ways okay +and have the same same sort of error + + align:start position:0% +and have the same same sort of error + + + align:start position:0% +and have the same same sort of error +level out here okay but different + + align:start position:0% +level out here okay but different + + + align:start position:0% +level out here okay but different +coefficients associated with the air but + + align:start position:0% +coefficients associated with the air but + + + align:start position:0% +coefficients associated with the air but +the same overall scaling and then you + + align:start position:0% +the same overall scaling and then you + + + align:start position:0% +the same overall scaling and then you +might choose different approximations + + align:start position:0% +might choose different approximations + + + align:start position:0% +might choose different approximations +for other reasons Sam + + align:start position:0% + + + + align:start position:0% + +well I mean yeah so if let's say you go + + align:start position:0% +well I mean yeah so if let's say you go + + + align:start position:0% +well I mean yeah so if let's say you go +out further right what's the next term + + align:start position:0% +out further right what's the next term + + + align:start position:0% +out further right what's the next term +here it's gonna be one over six F triple + + align:start position:0% +here it's gonna be one over six F triple + + + align:start position:0% +here it's gonna be one over six F triple +prime X I Delta X cubed okay and here + + align:start position:0% +prime X I Delta X cubed okay and here + + + align:start position:0% +prime X I Delta X cubed okay and here +you'll have minus that because I cube + + align:start position:0% +you'll have minus that because I cube + + + align:start position:0% +you'll have minus that because I cube +the Delta X so when I combine them right + + align:start position:0% +the Delta X so when I combine them right + + + align:start position:0% +the Delta X so when I combine them right +I'll actually get 1 over 3 F triple + + align:start position:0% +I'll actually get 1 over 3 F triple + + + align:start position:0% +I'll actually get 1 over 3 F triple +prime and so I could I could do a little + + align:start position:0% +prime and so I could I could do a little + + + align:start position:0% +prime and so I could I could do a little +better if I knew what my function was I + + align:start position:0% +better if I knew what my function was I + + + align:start position:0% +better if I knew what my function was I +can tell you exactly how big the air was + + align:start position:0% +can tell you exactly how big the air was + + + align:start position:0% +can tell you exactly how big the air was +right I can tell you that it was as big + + align:start position:0% +right I can tell you that it was as big + + + align:start position:0% +right I can tell you that it was as big +as the third derivative of F my function + + align:start position:0% +as the third derivative of F my function + + + align:start position:0% +as the third derivative of F my function +doesn't have a third derivative at that + + align:start position:0% +doesn't have a third derivative at that + + + align:start position:0% +doesn't have a third derivative at that +point the air might be huge and it's + + align:start position:0% +point the air might be huge and it's + + + align:start position:0% +point the air might be huge and it's +possible to construct functions that + + align:start position:0% +possible to construct functions that + + + align:start position:0% +possible to construct functions that +that lack that particular property ok so + + align:start position:0% +that lack that particular property ok so + + + align:start position:0% +that lack that particular property ok so +you can go out further and you can use + + align:start position:0% +you can go out further and you can use + + + align:start position:0% +you can go out further and you can use +it to sort of quantify exactly exactly + + align:start position:0% +it to sort of quantify exactly exactly + + + align:start position:0% +it to sort of quantify exactly exactly +how big you think the air might be in + + align:start position:0% +how big you think the air might be in + + + align:start position:0% +how big you think the air might be in +the approximation it's all constructed + + align:start position:0% +the approximation it's all constructed + + + align:start position:0% +the approximation it's all constructed +from linear combinations of different + + align:start position:0% +from linear combinations of different + + + align:start position:0% +from linear combinations of different +Taylor expansions ok about nearby points + + align:start position:0% +Taylor expansions ok about nearby points + + + align:start position:0% +Taylor expansions ok about nearby points +and and the related problem actually the + + align:start position:0% +and and the related problem actually the + + + align:start position:0% +and and the related problem actually the +equivalent problem is polynomial + + align:start position:0% +equivalent problem is polynomial + + + align:start position:0% +equivalent problem is polynomial +interpolation ok + + align:start position:0% +interpolation ok + + + align:start position:0% +interpolation ok +so the sort of if you can somehow in + + align:start position:0% +so the sort of if you can somehow in + + + align:start position:0% +so the sort of if you can somehow in +your mind transpose this problem it + + align:start position:0% +your mind transpose this problem it + + + align:start position:0% +your mind transpose this problem it +looks a lot like polynomial + + align:start position:0% +looks a lot like polynomial + + + align:start position:0% +looks a lot like polynomial +interpolation so these two are + + align:start position:0% +interpolation so these two are + + + align:start position:0% +interpolation so these two are +intimately related to each other yeah + + align:start position:0% +intimately related to each other yeah + + + align:start position:0% +intimately related to each other yeah +yes how much do you have to know about + + align:start position:0% +yes how much do you have to know about + + + align:start position:0% +yes how much do you have to know about +polynomial interpolation well say that + + align:start position:0% +polynomial interpolation well say that + + + align:start position:0% +polynomial interpolation well say that +again what do I want to say about that I + + align:start position:0% +again what do I want to say about that I + + + align:start position:0% +again what do I want to say about that I +wouldn't expect that level of detail I + + align:start position:0% +wouldn't expect that level of detail I + + + align:start position:0% +wouldn't expect that level of detail I +think it's quite difficult to construct + + align:start position:0% +think it's quite difficult to construct + + + align:start position:0% +think it's quite difficult to construct +Lagrange polynomial expansions by hand I + + align:start position:0% +Lagrange polynomial expansions by hand I + + + align:start position:0% +Lagrange polynomial expansions by hand I +don't know anyone who does that + + align:start position:0% +don't know anyone who does that + + + align:start position:0% +don't know anyone who does that +professionally or for pleasure I think + + align:start position:0% +professionally or for pleasure I think + + + align:start position:0% +professionally or for pleasure I think +I think that's a I think that's a bad + + align:start position:0% +I think that's a I think that's a bad + + + align:start position:0% +I think that's a I think that's a bad +idea you should understand polynomial + + align:start position:0% +idea you should understand polynomial + + + align:start position:0% +idea you should understand polynomial +interpolation you should understand the + + align:start position:0% +interpolation you should understand the + + + align:start position:0% +interpolation you should understand the +contexts in which it's important right + + align:start position:0% +contexts in which it's important right + + + align:start position:0% +contexts in which it's important right +when is Paulette what is polynomial + + align:start position:0% +when is Paulette what is polynomial + + + align:start position:0% +when is Paulette what is polynomial +interpolation for important for + + align:start position:0% +interpolation for important for + + + align:start position:0% +interpolation for important for +numerically do you recall her sure + + align:start position:0% +numerically do you recall her sure + + + align:start position:0% +numerically do you recall her sure +numerical integration right so this was + + align:start position:0% +numerical integration right so this was + + + align:start position:0% +numerical integration right so this was +this was really the key to numerical + + align:start position:0% +this was really the key to numerical + + + align:start position:0% +this was really the key to numerical +integration was trying to construct + + align:start position:0% +integration was trying to construct + + + align:start position:0% +integration was trying to construct +appropriate approximations of our + + align:start position:0% +appropriate approximations of our + + + align:start position:0% +appropriate approximations of our +function from a finite set of data and + + align:start position:0% +function from a finite set of data and + + + align:start position:0% +function from a finite set of data and +figure out the area under the curve so + + align:start position:0% +figure out the area under the curve so + + + align:start position:0% +figure out the area under the curve so +you should you should understand how one + + align:start position:0% +you should you should understand how one + + + align:start position:0% +you should you should understand how one +uses polynomial interpolation to do + + align:start position:0% +uses polynomial interpolation to do + + + align:start position:0% +uses polynomial interpolation to do +numerical integration but I wouldn't + + align:start position:0% +numerical integration but I wouldn't + + + align:start position:0% +numerical integration but I wouldn't +expect us to ask you to to actually + + align:start position:0% +expect us to ask you to to actually + + + align:start position:0% +expect us to ask you to to actually +compute polynomial interpolant and and + + align:start position:0% +compute polynomial interpolant and and + + + align:start position:0% +compute polynomial interpolant and and +numerically integrate it by hand I think + + align:start position:0% +numerically integrate it by hand I think + + + align:start position:0% +numerically integrate it by hand I think +that didn't exist that's too much okay + + align:start position:0% +that didn't exist that's too much okay + + + align:start position:0% +that didn't exist that's too much okay +okay four questions first sure for OTE + + align:start position:0% +okay four questions first sure for OTE + + + align:start position:0% +okay four questions first sure for OTE +OTE IBP okay okay so we have to have an + + align:start position:0% +OTE IBP okay okay so we have to have an + + + align:start position:0% +OTE IBP okay okay so we have to have an +OD we want to solve can I just do can I + + align:start position:0% +OD we want to solve can I just do can I + + + align:start position:0% +OD we want to solve can I just do can I +do one one dimensional unknown do I need + + align:start position:0% +do one one dimensional unknown do I need + + + align:start position:0% +do one one dimensional unknown do I need +to do a vector here can I just would you + + align:start position:0% +to do a vector here can I just would you + + + align:start position:0% +to do a vector here can I just would you +be satisfied if I wrote this as F of yn + + align:start position:0% +be satisfied if I wrote this as F of yn + + + align:start position:0% +be satisfied if I wrote this as F of yn +T and that it's sufficiently general + + align:start position:0% +T and that it's sufficiently general + + + align:start position:0% +T and that it's sufficiently general +that wait out that blame me when I + + align:start position:0% +that wait out that blame me when I + + + align:start position:0% +that wait out that blame me when I +forget to underscore things along the + + align:start position:0% +forget to underscore things along the + + + align:start position:0% +forget to underscore things along the +way and we don't have to think about + + align:start position:0% +way and we don't have to think about + + + align:start position:0% +way and we don't have to think about +such Akopian or anything like that okay + + align:start position:0% +such Akopian or anything like that okay + + + align:start position:0% +such Akopian or anything like that okay +so oh time derivative right so there's + + align:start position:0% +so oh time derivative right so there's + + + align:start position:0% +so oh time derivative right so there's +the OD we're gonna solve the trapezoid + + align:start position:0% +the OD we're gonna solve the trapezoid + + + align:start position:0% +the OD we're gonna solve the trapezoid +rule okay so let's + + align:start position:0% + + + + align:start position:0% + +do this the following way especially I + + align:start position:0% +do this the following way especially I + + + align:start position:0% +do this the following way especially I +wind up looking very similar to what we + + align:start position:0% +wind up looking very similar to what we + + + align:start position:0% +wind up looking very similar to what we +just did which is useful I might even be + + align:start position:0% +just did which is useful I might even be + + + align:start position:0% +just did which is useful I might even be +able to pull that board down and reuse + + align:start position:0% +able to pull that board down and reuse + + + align:start position:0% +able to pull that board down and reuse +it at a certain point so that'll be good + + align:start position:0% +it at a certain point so that'll be good + + + align:start position:0% +it at a certain point so that'll be good +let's do this so what is ultimately what + + align:start position:0% +let's do this so what is ultimately what + + + align:start position:0% +let's do this so what is ultimately what +is ODI VP solving like what are you + + align:start position:0% +is ODI VP solving like what are you + + + align:start position:0% +is ODI VP solving like what are you +trying to do when you solve one of these + + align:start position:0% +trying to do when you solve one of these + + + align:start position:0% +trying to do when you solve one of these +things it's extrapolation right I don't + + align:start position:0% +things it's extrapolation right I don't + + + align:start position:0% +things it's extrapolation right I don't +I know the value of y initially I'm + + align:start position:0% +I know the value of y initially I'm + + + align:start position:0% +I know the value of y initially I'm +trying to figure out where the hell this + + align:start position:0% +trying to figure out where the hell this + + + align:start position:0% +trying to figure out where the hell this +thing is going okay I've gotta + + align:start position:0% +thing is going okay I've gotta + + + align:start position:0% +thing is going okay I've gotta +extrapolate forward and you should be + + align:start position:0% +extrapolate forward and you should be + + + align:start position:0% +extrapolate forward and you should be +very uncomfortable with the notion that + + align:start position:0% +very uncomfortable with the notion that + + + align:start position:0% +very uncomfortable with the notion that +I can do that right how good a job can I + + align:start position:0% +I can do that right how good a job can I + + + align:start position:0% +I can do that right how good a job can I +do predicting the future knowing how + + align:start position:0% +do predicting the future knowing how + + + align:start position:0% +do predicting the future knowing how +things are now it's really quite quite + + align:start position:0% +things are now it's really quite quite + + + align:start position:0% +things are now it's really quite quite +complicated in fact it's so complicated + + align:start position:0% +complicated in fact it's so complicated + + + align:start position:0% +complicated in fact it's so complicated +right there are certain circumstances in + + align:start position:0% +right there are certain circumstances in + + + align:start position:0% +right there are certain circumstances in +which it's not really possible + + align:start position:0% +which it's not really possible + + + align:start position:0% +which it's not really possible +discovered here at MIT actually right so + + align:start position:0% +discovered here at MIT actually right so + + + align:start position:0% +discovered here at MIT actually right so +there was weather research going on at a + + align:start position:0% +there was weather research going on at a + + + align:start position:0% +there was weather research going on at a +certain point at MIT right it's a very + + align:start position:0% +certain point at MIT right it's a very + + + align:start position:0% +certain point at MIT right it's a very +famous case researcher a very famous + + align:start position:0% +famous case researcher a very famous + + + align:start position:0% +famous case researcher a very famous +researcher was doing numerical + + align:start position:0% +researcher was doing numerical + + + align:start position:0% +researcher was doing numerical +simulations of a weather model in Eau de + + align:start position:0% +simulations of a weather model in Eau de + + + align:start position:0% +simulations of a weather model in Eau de +IVP okay he ran it for a while and he + + align:start position:0% +IVP okay he ran it for a while and he + + + align:start position:0% +IVP okay he ran it for a while and he +stopped he looked at his end state right + + align:start position:0% +stopped he looked at his end state right + + + align:start position:0% +stopped he looked at his end state right +the last value of y in his simulation + + align:start position:0% +the last value of y in his simulation + + + align:start position:0% +the last value of y in his simulation +he put in three digits used that as the + + align:start position:0% +he put in three digits used that as the + + + align:start position:0% +he put in three digits used that as the +initial condition and started a + + align:start position:0% +initial condition and started a + + + align:start position:0% +initial condition and started a +simulation again and it went wacky right + + align:start position:0% +simulation again and it went wacky right + + + align:start position:0% +simulation again and it went wacky right +didn't look anything like the initial + + align:start position:0% +didn't look anything like the initial + + + align:start position:0% +didn't look anything like the initial +solution okay + + align:start position:0% +solution okay + + + align:start position:0% +solution okay +how did that happen right it seemed fine + + align:start position:0% +how did that happen right it seemed fine + + + align:start position:0% +how did that happen right it seemed fine +up to that point solutions cranking + + align:start position:0% +up to that point solutions cranking + + + align:start position:0% +up to that point solutions cranking +along he stopped okay he took three + + align:start position:0% +along he stopped okay he took three + + + align:start position:0% +along he stopped okay he took three +digits accuracy out of the computer and + + align:start position:0% +digits accuracy out of the computer and + + + align:start position:0% +digits accuracy out of the computer and +he started again and it did something + + align:start position:0% +he started again and it did something + + + align:start position:0% +he started again and it did something +else okay all right so there they're + + align:start position:0% +else okay all right so there they're + + + align:start position:0% +else okay all right so there they're +problems that are inherently chaotic and + + align:start position:0% +problems that are inherently chaotic and + + + align:start position:0% +problems that are inherently chaotic and +very sensitive to their initial + + align:start position:0% +very sensitive to their initial + + + align:start position:0% +very sensitive to their initial +conditions right they're hard to resolve + + align:start position:0% +conditions right they're hard to resolve + + + align:start position:0% +conditions right they're hard to resolve +so the entire point of doing this sort + + align:start position:0% +so the entire point of doing this sort + + + align:start position:0% +so the entire point of doing this sort +of analysis of OD IV pieces at least in + + align:start position:0% +of analysis of OD IV pieces at least in + + + align:start position:0% +of analysis of OD IV pieces at least in +the best case scenarios right we want to + + align:start position:0% +the best case scenarios right we want to + + + align:start position:0% +the best case scenarios right we want to +try to manage the error associated with + + align:start position:0% +try to manage the error associated with + + + align:start position:0% +try to manage the error associated with +these kinds of extrapolation in some + + align:start position:0% +these kinds of extrapolation in some + + + align:start position:0% +these kinds of extrapolation in some +cases it's really not it's really not + + align:start position:0% +cases it's really not it's really not + + + align:start position:0% +cases it's really not it's really not +very possible okay you don't know the + + align:start position:0% +very possible okay you don't know the + + + align:start position:0% +very possible okay you don't know the +initial conditions well enough to + + align:start position:0% +initial conditions well enough to + + + align:start position:0% +initial conditions well enough to +predict what the final state is so there + + align:start position:0% +predict what the final state is so there + + + align:start position:0% +predict what the final state is so there +are problems that are inherently + + align:start position:0% +are problems that are inherently + + + align:start position:0% +are problems that are inherently +unstable or sensitive to their initial + + align:start position:0% +unstable or sensitive to their initial + + + align:start position:0% +unstable or sensitive to their initial +conditions they don't have to blow up + + align:start position:0% +conditions they don't have to blow up + + + align:start position:0% +conditions they don't have to blow up +either they can find themselves moving + + align:start position:0% +either they can find themselves moving + + + align:start position:0% +either they can find themselves moving +through the phase space + + align:start position:0% +through the phase space + + + align:start position:0% +through the phase space +in some way that's very very sensitive + + align:start position:0% +in some way that's very very sensitive + + + align:start position:0% +in some way that's very very sensitive +and two points that start very close + + align:start position:0% +and two points that start very close + + + align:start position:0% +and two points that start very close +together can wind up very part of a far + + align:start position:0% +together can wind up very part of a far + + + align:start position:0% +together can wind up very part of a far +apart from each other okay so it's + + align:start position:0% +apart from each other okay so it's + + + align:start position:0% +apart from each other okay so it's +deterministic chaos but outside of those + + align:start position:0% +deterministic chaos but outside of those + + + align:start position:0% +deterministic chaos but outside of those +problems right we try to do this + + align:start position:0% +problems right we try to do this + + + align:start position:0% +problems right we try to do this +extrapolation and figure out figure out + + align:start position:0% +extrapolation and figure out figure out + + + align:start position:0% +extrapolation and figure out figure out +sort of a best approximation for where + + align:start position:0% +sort of a best approximation for where + + + align:start position:0% +sort of a best approximation for where +we think right our target function is + + align:start position:0% +we think right our target function is + + + align:start position:0% +we think right our target function is +going so what are we trying to do + + align:start position:0% +going so what are we trying to do + + + align:start position:0% +going so what are we trying to do +in principle okay we know why at a + + align:start position:0% +in principle okay we know why at a + + + align:start position:0% +in principle okay we know why at a +certain point okay and we want to know + + align:start position:0% +certain point okay and we want to know + + + align:start position:0% +certain point okay and we want to know +where it's where it's gonna go okay and + + align:start position:0% +where it's where it's gonna go okay and + + + align:start position:0% +where it's where it's gonna go okay and +so you might say well maybe I know dy DT + + align:start position:0% +so you might say well maybe I know dy DT + + + align:start position:0% +so you might say well maybe I know dy DT +initially and so I should just move a + + align:start position:0% +initially and so I should just move a + + + align:start position:0% +initially and so I should just move a +small increment along that slope and + + align:start position:0% +small increment along that slope and + + + align:start position:0% +small increment along that slope and +that's a good approximation let's the + + align:start position:0% +that's a good approximation let's the + + + align:start position:0% +that's a good approximation let's the +forward Euler approximation and + + align:start position:0% +forward Euler approximation and + + + align:start position:0% +forward Euler approximation and +trapezoid rule or equivalently the + + align:start position:0% +trapezoid rule or equivalently the + + + align:start position:0% +trapezoid rule or equivalently the +midpoint rule + + align:start position:0% +midpoint rule + + + align:start position:0% +midpoint rule +okay says well maybe maybe that initial + + align:start position:0% +okay says well maybe maybe that initial + + + align:start position:0% +okay says well maybe maybe that initial +slope isn't really the right one to use + + align:start position:0% +slope isn't really the right one to use + + + align:start position:0% +slope isn't really the right one to use +okay maybe why this something like this + + align:start position:0% +okay maybe why this something like this + + + align:start position:0% +okay maybe why this something like this +and we should actually look sort of + + align:start position:0% +and we should actually look sort of + + + align:start position:0% +and we should actually look sort of +halfway between the point we're trying + + align:start position:0% +halfway between the point we're trying + + + align:start position:0% +halfway between the point we're trying +to extrapolate to and the current point + + align:start position:0% +to extrapolate to and the current point + + + align:start position:0% +to extrapolate to and the current point +right and use that value right as the + + align:start position:0% +right and use that value right as the + + + align:start position:0% +right and use that value right as the +best approximation of the derivative and + + align:start position:0% +best approximation of the derivative and + + + align:start position:0% +best approximation of the derivative and +extrapolate forward along that and it + + align:start position:0% +extrapolate forward along that and it + + + align:start position:0% +extrapolate forward along that and it +turns out that's more accurate okay so + + align:start position:0% +turns out that's more accurate okay so + + + align:start position:0% +turns out that's more accurate okay so +what does that look like + + align:start position:0% +what does that look like + + + align:start position:0% +what does that look like +so one typically says you know why I + + align:start position:0% +so one typically says you know why I + + + align:start position:0% +so one typically says you know why I +plus 1 is equal to okay why I plus delta + + align:start position:0% +plus 1 is equal to okay why I plus delta + + + align:start position:0% +plus 1 is equal to okay why I plus delta +T times F why I plus 1/2 comma and we + + align:start position:0% +T times F why I plus 1/2 comma and we + + + align:start position:0% +T times F why I plus 1/2 comma and we +won't worry about the T here but it's + + align:start position:0% +won't worry about the T here but it's + + + align:start position:0% +won't worry about the T here but it's +gonna have to be TI plus 1/2 so I look + + align:start position:0% +gonna have to be TI plus 1/2 so I look + + + align:start position:0% +gonna have to be TI plus 1/2 so I look +halfway forward in time and I say that's + + align:start position:0% +halfway forward in time and I say that's + + + align:start position:0% +halfway forward in time and I say that's +the slope that's the derivative of Y so + + align:start position:0% +the slope that's the derivative of Y so + + + align:start position:0% +the slope that's the derivative of Y so +let me step forward along that line okay + + align:start position:0% +let me step forward along that line okay + + + align:start position:0% +let me step forward along that line okay +let's turn up this is going to be this + + align:start position:0% +let's turn up this is going to be this + + + align:start position:0% +let's turn up this is going to be this +is gonna be reasonably accurate if I can + + align:start position:0% +is gonna be reasonably accurate if I can + + + align:start position:0% +is gonna be reasonably accurate if I can +get a good approximation for y I plus a + + align:start position:0% +get a good approximation for y I plus a + + + align:start position:0% +get a good approximation for y I plus a +half okay okay so let's excuse me yeah + + align:start position:0% +half okay okay so let's excuse me yeah + + + align:start position:0% +half okay okay so let's excuse me yeah +they're there they're functionally + + align:start position:0% +they're there they're functionally + + + align:start position:0% +they're there they're functionally +equivalent to each other they work they + + align:start position:0% +equivalent to each other they work they + + + align:start position:0% +equivalent to each other they work they +work in precisely the same fashion okay + + align:start position:0% +work in precisely the same fashion okay + + + align:start position:0% +work in precisely the same fashion okay +so whether it's the trapezoidal world + + align:start position:0% +so whether it's the trapezoidal world + + + align:start position:0% +so whether it's the trapezoidal world +the midpoint method they they have + + align:start position:0% +the midpoint method they they have + + + align:start position:0% +the midpoint method they they have +fundamentally the same fundamentally the + + align:start position:0% +fundamentally the same fundamentally the + + + align:start position:0% +fundamentally the same fundamentally the +same picture is there okay here right if + + align:start position:0% +same picture is there okay here right if + + + align:start position:0% +same picture is there okay here right if +you do forward Euler you're doing + + align:start position:0% +you do forward Euler you're doing + + + align:start position:0% +you do forward Euler you're doing +numerical integration assuming the slope + + align:start position:0% +numerical integration assuming the slope + + + align:start position:0% +numerical integration assuming the slope +is the value at this point if you're + + align:start position:0% +is the value at this point if you're + + + align:start position:0% +is the value at this point if you're +doing the midpoint method or the + + align:start position:0% +doing the midpoint method or the + + + align:start position:0% +doing the midpoint method or the +trapezoid rule you're trying to get a + + align:start position:0% +trapezoid rule you're trying to get a + + + align:start position:0% +trapezoid rule you're trying to get a +better approximation for this slope + + align:start position:0% +better approximation for this slope + + + align:start position:0% +better approximation for this slope +right so you're trying to build a + + align:start position:0% +right so you're trying to build a + + + align:start position:0% +right so you're trying to build a +trapezoid and integrate the area under + + align:start position:0% +trapezoid and integrate the area under + + + align:start position:0% +trapezoid and integrate the area under +that trapezoid okay so they're + + align:start position:0% +that trapezoid okay so they're + + + align:start position:0% +that trapezoid okay so they're +fundamentally the same thing okay now + + align:start position:0% +fundamentally the same thing okay now + + + align:start position:0% +fundamentally the same thing okay now +the question becomes + + align:start position:0% +the question becomes + + + align:start position:0% +the question becomes +I don't know F at Y I plus two so I need + + align:start position:0% +I don't know F at Y I plus two so I need + + + align:start position:0% +I don't know F at Y I plus two so I need +to use a Taylor expansion of this + + align:start position:0% +to use a Taylor expansion of this + + + align:start position:0% +to use a Taylor expansion of this +quantity in terms of the value of f that + + align:start position:0% +quantity in terms of the value of f that + + + align:start position:0% +quantity in terms of the value of f that +I know so I need to expand this in terms + + align:start position:0% +I know so I need to expand this in terms + + + align:start position:0% +I know so I need to expand this in terms +of F at Y I okay and I'll know the + + align:start position:0% +of F at Y I okay and I'll know the + + + align:start position:0% +of F at Y I okay and I'll know the +derivative of Y with respect to T at Y I + + align:start position:0% +derivative of Y with respect to T at Y I + + + align:start position:0% +derivative of Y with respect to T at Y I +I know from this formula so if I take + + align:start position:0% +I know from this formula so if I take + + + align:start position:0% +I know from this formula so if I take +this Taylor expansion okay and I carry + + align:start position:0% +this Taylor expansion okay and I carry + + + align:start position:0% +this Taylor expansion okay and I carry +it out to the first term I don't know + + align:start position:0% +it out to the first term I don't know + + + align:start position:0% +it out to the first term I don't know +okay which is the order delta T squared + + align:start position:0% +okay which is the order delta T squared + + + align:start position:0% +okay which is the order delta T squared +term okay and a carry through all of the + + align:start position:0% +term okay and a carry through all of the + + + align:start position:0% +term okay and a carry through all of the +airs right I'll find out that there's a + + align:start position:0% +airs right I'll find out that there's a + + + align:start position:0% +airs right I'll find out that there's a +numerical error proportional to order + + align:start position:0% +numerical error proportional to order + + + align:start position:0% +numerical error proportional to order +delta T squared + + align:start position:0% +delta T squared + + + align:start position:0% +delta T squared +yes I need to do exactly this okay and + + align:start position:0% +yes I need to do exactly this okay and + + + align:start position:0% +yes I need to do exactly this okay and +substitute in terms of quantities I know + + align:start position:0% +substitute in terms of quantities I know + + + align:start position:0% +substitute in terms of quantities I know +when quantities I don't know okay and + + align:start position:0% +when quantities I don't know okay and + + + align:start position:0% +when quantities I don't know okay and +the leading order contribution of the + + align:start position:0% +the leading order contribution of the + + + align:start position:0% +the leading order contribution of the +quantities I don't know will give me + + align:start position:0% +quantities I don't know will give me + + + align:start position:0% +quantities I don't know will give me +this order delta T squared piece that'll + + align:start position:0% +this order delta T squared piece that'll + + + align:start position:0% +this order delta T squared piece that'll +give me the local truncation error in + + align:start position:0% +give me the local truncation error in + + + align:start position:0% +give me the local truncation error in +the solution that makes sense so it's + + align:start position:0% +the solution that makes sense so it's + + + align:start position:0% +the solution that makes sense so it's +still Taylor expansions good other + + align:start position:0% +still Taylor expansions good other + + + align:start position:0% +still Taylor expansions good other +questions yes + + align:start position:0% + + + + align:start position:0% + +why is the central difference I don't + + align:start position:0% +why is the central difference I don't + + + align:start position:0% +why is the central difference I don't +think I said anything like that so + + align:start position:0% +think I said anything like that so + + + align:start position:0% +think I said anything like that so +implicit versus explicit really depends + + align:start position:0% +implicit versus explicit really depends + + + align:start position:0% +implicit versus explicit really depends +on on what you're trying to do okay so + + align:start position:0% +on on what you're trying to do okay so + + + align:start position:0% +on on what you're trying to do okay so +if I'm trying to use a central + + align:start position:0% +if I'm trying to use a central + + + align:start position:0% +if I'm trying to use a central +difference formula of some sort to solve + + align:start position:0% +difference formula of some sort to solve + + + align:start position:0% +difference formula of some sort to solve +an OD e which progresses forward in time + + align:start position:0% +an OD e which progresses forward in time + + + align:start position:0% +an OD e which progresses forward in time +right it has a direction associated with + + align:start position:0% +right it has a direction associated with + + + align:start position:0% +right it has a direction associated with +it that things always progress in then + + align:start position:0% +it that things always progress in then + + + align:start position:0% +it that things always progress in then +this this might be an explicit formula + + align:start position:0% +this this might be an explicit formula + + + align:start position:0% +this this might be an explicit formula +because I could solve right for F at X I + + align:start position:0% +because I could solve right for F at X I + + + align:start position:0% +because I could solve right for F at X I +plus one in terms of what's going on in + + align:start position:0% +plus one in terms of what's going on in + + + align:start position:0% +plus one in terms of what's going on in +the past if we tried to do finite + + align:start position:0% +the past if we tried to do finite + + + align:start position:0% +the past if we tried to do finite +differences in a boundary value problem + + align:start position:0% +differences in a boundary value problem + + + align:start position:0% +differences in a boundary value problem +instead okay and that boundary value + + align:start position:0% +instead okay and that boundary value + + + align:start position:0% +instead okay and that boundary value +from doesn't have some direction + + align:start position:0% +from doesn't have some direction + + + align:start position:0% +from doesn't have some direction +associated with it anymore right so it's + + align:start position:0% +associated with it anymore right so it's + + + align:start position:0% +associated with it anymore right so it's +not like space has some preferred + + align:start position:0% +not like space has some preferred + + + align:start position:0% +not like space has some preferred +direction Ty and goes in a preferred + + align:start position:0% +direction Ty and goes in a preferred + + + align:start position:0% +direction Ty and goes in a preferred +direction space does not okay you may + + align:start position:0% +direction space does not okay you may + + + align:start position:0% +direction space does not okay you may +find that the point-wise equations you + + align:start position:0% +find that the point-wise equations you + + + align:start position:0% +find that the point-wise equations you +write down cannot be solved right + + align:start position:0% +write down cannot be solved right + + + align:start position:0% +write down cannot be solved right +strictly in terms of one of these you + + align:start position:0% +strictly in terms of one of these you + + + align:start position:0% +strictly in terms of one of these you +can't can't just move this to the other + + align:start position:0% +can't can't just move this to the other + + + align:start position:0% +can't can't just move this to the other +side of the equation and solve in terms + + align:start position:0% +side of the equation and solve in terms + + + align:start position:0% +side of the equation and solve in terms +of everything else you'll have a coupled + + align:start position:0% +of everything else you'll have a coupled + + + align:start position:0% +of everything else you'll have a coupled +set of equations that can't be can't be + + align:start position:0% +set of equations that can't be can't be + + + align:start position:0% +set of equations that can't be can't be +diagonalized can't be simply simply + + align:start position:0% +diagonalized can't be simply simply + + + align:start position:0% +diagonalized can't be simply simply +reduced they won't have the form of save + + align:start position:0% +reduced they won't have the form of save + + + align:start position:0% +reduced they won't have the form of save +triangular matrix for example okay this + + align:start position:0% +triangular matrix for example okay this + + + align:start position:0% +triangular matrix for example okay this +this will happen okay and in that case + + align:start position:0% +this will happen okay and in that case + + + align:start position:0% +this will happen okay and in that case +this you would say this formulas + + align:start position:0% +this you would say this formulas + + + align:start position:0% +this you would say this formulas +implicit okay so it really depends on + + align:start position:0% +implicit okay so it really depends on + + + align:start position:0% +implicit okay so it really depends on +which problem you're trying to solve + + align:start position:0% +which problem you're trying to solve + + + align:start position:0% +which problem you're trying to solve +whether you label them explicit or + + align:start position:0% +whether you label them explicit or + + + align:start position:0% +whether you label them explicit or +implicit explicit is going to mean that + + align:start position:0% +implicit explicit is going to mean that + + + align:start position:0% +implicit explicit is going to mean that +the data I want okay can be found with a + + align:start position:0% +the data I want okay can be found with a + + + align:start position:0% +the data I want okay can be found with a +simple equation solve in terms of the + + align:start position:0% +simple equation solve in terms of the + + + align:start position:0% +simple equation solve in terms of the +data I know in places' can mean I've got + + align:start position:0% +data I know in places' can mean I've got + + + align:start position:0% +data I know in places' can mean I've got +to do some complicated equation solving + + align:start position:0% +to do some complicated equation solving + + + align:start position:0% +to do some complicated equation solving +methodology right I've got to I've got + + align:start position:0% +methodology right I've got to I've got + + + align:start position:0% +methodology right I've got to I've got +to go do Gaussian elimination I need to + + align:start position:0% +to go do Gaussian elimination I need to + + + align:start position:0% +to go do Gaussian elimination I need to +go to F solve and solve this thing right + + align:start position:0% +go to F solve and solve this thing right + + + align:start position:0% +go to F solve and solve this thing right +the data that I want is not not + + align:start position:0% +the data that I want is not not + + + align:start position:0% +the data that I want is not not +available through some simple some + + align:start position:0% +available through some simple some + + + align:start position:0% +available through some simple some +simple scheme where I can just write + + align:start position:0% +simple scheme where I can just write + + + align:start position:0% +simple scheme where I can just write +explicit + + align:start position:0% +explicit + + + align:start position:0% +explicit +the thing I want equals some function of + + align:start position:0% +the thing I want equals some function of + + + align:start position:0% +the thing I want equals some function of +things I know okay other questions okay + + align:start position:0% +things I know okay other questions okay + + + align:start position:0% +things I know okay other questions okay +yeah yeah oh man + + align:start position:0% + + + + align:start position:0% + +the question was how many questions and + + align:start position:0% +the question was how many questions and + + + align:start position:0% +the question was how many questions and +how many sub questions on the quiz yeah + + align:start position:0% +how many sub questions on the quiz yeah + + + align:start position:0% +how many sub questions on the quiz yeah +the quiz is it's it's in my opinion it's + + align:start position:0% +the quiz is it's it's in my opinion it's + + + align:start position:0% +the quiz is it's it's in my opinion it's +now shorter than the last one that you + + align:start position:0% +now shorter than the last one that you + + + align:start position:0% +now shorter than the last one that you +took we've been pretty sensitive to time + + align:start position:0% +took we've been pretty sensitive to time + + + align:start position:0% +took we've been pretty sensitive to time +concerns we know that was something that + + align:start position:0% +concerns we know that was something that + + + align:start position:0% +concerns we know that was something that +was an issue on the previous quiz I + + align:start position:0% +was an issue on the previous quiz I + + + align:start position:0% +was an issue on the previous quiz I +think there is only going to be two + + align:start position:0% +think there is only going to be two + + + align:start position:0% +think there is only going to be two +problems on it okay + + align:start position:0% +problems on it okay + + + align:start position:0% +problems on it okay +they have many parts but we've really + + align:start position:0% +they have many parts but we've really + + + align:start position:0% +they have many parts but we've really +tried to refine the questions in those + + align:start position:0% +tried to refine the questions in those + + + align:start position:0% +tried to refine the questions in those +parts okay that's that's that's what you + + align:start position:0% +parts okay that's that's that's what you + + + align:start position:0% +parts okay that's that's that's what you +should expect it's comprehensive covers + + align:start position:0% +should expect it's comprehensive covers + + + align:start position:0% +should expect it's comprehensive covers +all the things from this section okay + + align:start position:0% +all the things from this section okay + + + align:start position:0% +all the things from this section okay +yes yeah + + align:start position:0% + + + + align:start position:0% + +yes sure sure so so higher index daes + + align:start position:0% +yes sure sure so so higher index daes + + + align:start position:0% +yes sure sure so so higher index daes +okay come up all the time and the + + align:start position:0% +okay come up all the time and the + + + align:start position:0% +okay come up all the time and the +degrees of freedom refers to your + + align:start position:0% +degrees of freedom refers to your + + + align:start position:0% +degrees of freedom refers to your +ability to choose initial conditions for + + align:start position:0% +ability to choose initial conditions for + + + align:start position:0% +ability to choose initial conditions for +the problem and we saw several examples + + align:start position:0% +the problem and we saw several examples + + + align:start position:0% +the problem and we saw several examples +in which if we try to convert that da e + + align:start position:0% +in which if we try to convert that da e + + + align:start position:0% +in which if we try to convert that da e +to an OD e we found along the way that + + align:start position:0% +to an OD e we found along the way that + + + align:start position:0% +to an OD e we found along the way that +there were certain hidden conditions + + align:start position:0% +there were certain hidden conditions + + + align:start position:0% +there were certain hidden conditions +that all the initial conditions would + + align:start position:0% +that all the initial conditions would + + + align:start position:0% +that all the initial conditions would +need to satisfy in order for this OD the + + align:start position:0% +need to satisfy in order for this OD the + + + align:start position:0% +need to satisfy in order for this OD the +system of Odie's that we built from the + + align:start position:0% +system of Odie's that we built from the + + + align:start position:0% +system of Odie's that we built from the +da's to follow the same solution path or + + align:start position:0% +da's to follow the same solution path or + + + align:start position:0% +da's to follow the same solution path or +solution manifold as the original da + + align:start position:0% +solution manifold as the original da + + + align:start position:0% +solution manifold as the original da +system would follow okay the higher the + + align:start position:0% +system would follow okay the higher the + + + align:start position:0% +system would follow okay the higher the +index is the more of these hidden + + align:start position:0% +index is the more of these hidden + + + align:start position:0% +index is the more of these hidden +constraints you find okay + + align:start position:0% +constraints you find okay + + + align:start position:0% +constraints you find okay +and those hidden constraints tell you + + align:start position:0% +and those hidden constraints tell you + + + align:start position:0% +and those hidden constraints tell you +that the initial conditions have to be + + align:start position:0% +that the initial conditions have to be + + + align:start position:0% +that the initial conditions have to be +very particular so there were there I've + + align:start position:0% +very particular so there were there I've + + + align:start position:0% +very particular so there were there I've +encouraged you to look at look at the + + align:start position:0% +encouraged you to look at look at the + + + align:start position:0% +encouraged you to look at look at the +specific examples in the notes and + + align:start position:0% +specific examples in the notes and + + + align:start position:0% +specific examples in the notes and +you'll see there was there was a simple + + align:start position:0% +you'll see there was there was a simple + + + align:start position:0% +you'll see there was there was a simple +CSTR example that was index 1 and almost + + align:start position:0% +CSTR example that was index 1 and almost + + + align:start position:0% +CSTR example that was index 1 and almost +almost unconstrained basically there was + + align:start position:0% +almost unconstrained basically there was + + + align:start position:0% +almost unconstrained basically there was +an index to Dae in which the consistent + + align:start position:0% +an index to Dae in which the consistent + + + align:start position:0% +an index to Dae in which the consistent +initial conditions you actually couldn't + + align:start position:0% +initial conditions you actually couldn't + + + align:start position:0% +initial conditions you actually couldn't +specify any of the initial conditions + + align:start position:0% +specify any of the initial conditions + + + align:start position:0% +specify any of the initial conditions +they were they were fixed by the + + align:start position:0% +they were they were fixed by the + + + align:start position:0% +they were they were fixed by the +equations themselves right + + align:start position:0% +equations themselves right + + + align:start position:0% +equations themselves right +remember that sort of happened because + + align:start position:0% +remember that sort of happened because + + + align:start position:0% +remember that sort of happened because +certain certain days are pathological in + + align:start position:0% +certain certain days are pathological in + + + align:start position:0% +certain certain days are pathological in +nature they often ask us to do something + + align:start position:0% +nature they often ask us to do something + + + align:start position:0% +nature they often ask us to do something +we can't do physically like you know try + + align:start position:0% +we can't do physically like you know try + + + align:start position:0% +we can't do physically like you know try +to control the input by or try to + + align:start position:0% +to control the input by or try to + + + align:start position:0% +to control the input by or try to +predict let's say how do I say this it's + + align:start position:0% +predict let's say how do I say this it's + + + align:start position:0% +predict let's say how do I say this it's +easy for us to predict the output + + align:start position:0% +easy for us to predict the output + + + align:start position:0% +easy for us to predict the output +knowing the input it's very hard for us + + align:start position:0% +knowing the input it's very hard for us + + + align:start position:0% +knowing the input it's very hard for us +to predict the input knowing the output + + align:start position:0% +to predict the input knowing the output + + + align:start position:0% +to predict the input knowing the output +right and these higher index Dae s were + + align:start position:0% +right and these higher index Dae s were + + + align:start position:0% +right and these higher index Dae s were +essentially asking us to do that right + + align:start position:0% +essentially asking us to do that right + + + align:start position:0% +essentially asking us to do that right +there's a lag in how we measure things + + align:start position:0% +there's a lag in how we measure things + + + align:start position:0% +there's a lag in how we measure things +and it's easier to go forward through a + + align:start position:0% +and it's easier to go forward through a + + + align:start position:0% +and it's easier to go forward through a +process than backwards through a process + + align:start position:0% +process than backwards through a process + + + align:start position:0% +process than backwards through a process +and make these predictions there's + + align:start position:0% +and make these predictions there's + + + align:start position:0% +and make these predictions there's +inherent sensitivity in doing the former + + align:start position:0% +inherent sensitivity in doing the former + + + align:start position:0% +inherent sensitivity in doing the former +it's the same sort of sensitivity you + + align:start position:0% +it's the same sort of sensitivity you + + + align:start position:0% +it's the same sort of sensitivity you +get from these systems of Odie's in fact + + align:start position:0% +get from these systems of Odie's in fact + + + align:start position:0% +get from these systems of Odie's in fact +right that's just small change in the + + align:start position:0% +right that's just small change in the + + + align:start position:0% +right that's just small change in the +initial conditions can lead to big + + align:start position:0% +initial conditions can lead to big + + + align:start position:0% +initial conditions can lead to big +changes in the outlet so if I measure + + align:start position:0% +changes in the outlet so if I measure + + + align:start position:0% +changes in the outlet so if I measure +the outlet it's hard to predict the + + align:start position:0% +the outlet it's hard to predict the + + + align:start position:0% +the outlet it's hard to predict the +inlet ok so it's just very inherently + + align:start position:0% +inlet ok so it's just very inherently + + + align:start position:0% +inlet ok so it's just very inherently +difficult to do and so formulating a + + align:start position:0% +difficult to do and so formulating a + + + align:start position:0% +difficult to do and so formulating a +model which has this high index right + + align:start position:0% +model which has this high index right + + + align:start position:0% +model which has this high index right +you will naturally find that your choice + + align:start position:0% +you will naturally find that your choice + + + align:start position:0% +you will naturally find that your choice +of initial conditions for the solution + + align:start position:0% +of initial conditions for the solution + + + align:start position:0% +of initial conditions for the solution +of that model are constrained and their + + align:start position:0% +of that model are constrained and their + + + align:start position:0% +of that model are constrained and their +constraint because of the way you + + align:start position:0% +constraint because of the way you + + + align:start position:0% +constraint because of the way you +formulated the model ok if you're + + align:start position:0% +formulated the model ok if you're + + + align:start position:0% +formulated the model ok if you're +actually trying to do control ok of a + + align:start position:0% +actually trying to do control ok of a + + + align:start position:0% +actually trying to do control ok of a +chemical process is gonna be very + + align:start position:0% +chemical process is gonna be very + + + align:start position:0% +chemical process is gonna be very +difficult ok to try to somehow control + + align:start position:0% +difficult ok to try to somehow control + + + align:start position:0% +difficult ok to try to somehow control +the you know try to make the input be a + + align:start position:0% +the you know try to make the input be a + + + align:start position:0% +the you know try to make the input be a +certain thing by controlling the output + + align:start position:0% +certain thing by controlling the output + + + align:start position:0% +certain thing by controlling the output +ok this is that doesn't make sense + + align:start position:0% +ok this is that doesn't make sense + + + align:start position:0% +ok this is that doesn't make sense +almost right it seems very very strange + + align:start position:0% +almost right it seems very very strange + + + align:start position:0% +almost right it seems very very strange +you would really want to change the + + align:start position:0% +you would really want to change the + + + align:start position:0% +you would really want to change the +input in order to hit a target in the + + align:start position:0% +input in order to hit a target in the + + + align:start position:0% +input in order to hit a target in the +output how do you change the output and + + align:start position:0% +output how do you change the output and + + + align:start position:0% +output how do you change the output and +hit a target in the input right the + + align:start position:0% +hit a target in the input right the + + + align:start position:0% +hit a target in the input right the +process doesn't actually care about + + align:start position:0% +process doesn't actually care about + + + align:start position:0% +process doesn't actually care about +things in that way and you saw that + + align:start position:0% +things in that way and you saw that + + + align:start position:0% +things in that way and you saw that +in that in that particular CSTR example + + align:start position:0% +in that in that particular CSTR example + + + align:start position:0% +in that in that particular CSTR example +you couldn't you couldn't fix any of the + + align:start position:0% +you couldn't you couldn't fix any of the + + + align:start position:0% +you couldn't you couldn't fix any of the +initial conditions actually right there + + align:start position:0% +initial conditions actually right there + + + align:start position:0% +initial conditions actually right there +was no free choice in the problem + + align:start position:0% +was no free choice in the problem + + + align:start position:0% +was no free choice in the problem +everything was automatically fixed + + align:start position:0% +everything was automatically fixed + + + align:start position:0% +everything was automatically fixed +they'd had to have perfect knowledge of + + align:start position:0% +they'd had to have perfect knowledge of + + + align:start position:0% +they'd had to have perfect knowledge of +everything in the system + + align:start position:0% +everything in the system + + + align:start position:0% +everything in the system +I wasn't actually able to do control in + + align:start position:0% +I wasn't actually able to do control in + + + align:start position:0% +I wasn't actually able to do control in +a sense there I just measure the output + + align:start position:0% +a sense there I just measure the output + + + align:start position:0% +a sense there I just measure the output +I could tell you what the input was + + align:start position:0% +I could tell you what the input was + + + align:start position:0% +I could tell you what the input was +supposed to be and it was super + + align:start position:0% +supposed to be and it was super + + + align:start position:0% +supposed to be and it was super +sensitive to my measurement okay so + + align:start position:0% +sensitive to my measurement okay so + + + align:start position:0% +sensitive to my measurement okay so +these high index problems tend to come + + align:start position:0% +these high index problems tend to come + + + align:start position:0% +these high index problems tend to come +up when we when we want to constrain + + align:start position:0% +up when we when we want to constrain + + + align:start position:0% +up when we when we want to constrain +things in a way that's it's a physically + + align:start position:0% +things in a way that's it's a physically + + + align:start position:0% +things in a way that's it's a physically +quite challenging okay high index + + align:start position:0% +quite challenging okay high index + + + align:start position:0% +quite challenging okay high index +problems are incredibly common in + + align:start position:0% +problems are incredibly common in + + + align:start position:0% +problems are incredibly common in +mechanical engineering things like + + align:start position:0% +mechanical engineering things like + + + align:start position:0% +mechanical engineering things like +robotics okay we you know you want to + + align:start position:0% +robotics okay we you know you want to + + + align:start position:0% +robotics okay we you know you want to +make sure the the robots arm doesn't + + align:start position:0% +make sure the the robots arm doesn't + + + align:start position:0% +make sure the the robots arm doesn't +whack someone in the head right this is + + align:start position:0% +whack someone in the head right this is + + + align:start position:0% +whack someone in the head right this is +important and so you're trying to + + align:start position:0% +important and so you're trying to + + + align:start position:0% +important and so you're trying to +constrain all these degrees of freedom + + align:start position:0% +constrain all these degrees of freedom + + + align:start position:0% +constrain all these degrees of freedom +and the paths that it's going to move on + + align:start position:0% +and the paths that it's going to move on + + + align:start position:0% +and the paths that it's going to move on +and all those constraints mean there's + + align:start position:0% +and all those constraints mean there's + + + align:start position:0% +and all those constraints mean there's +actually a very narrow envelope in which + + align:start position:0% +actually a very narrow envelope in which + + + align:start position:0% +actually a very narrow envelope in which +this thing gets to operate so accurately + + align:start position:0% +this thing gets to operate so accurately + + + align:start position:0% +this thing gets to operate so accurately +accurately simulating the motion and + + align:start position:0% +accurately simulating the motion and + + + align:start position:0% +accurately simulating the motion and +then making making the robot move that + + align:start position:0% +then making making the robot move that + + + align:start position:0% +then making making the robot move that +way is very important chemical processes + + align:start position:0% +way is very important chemical processes + + + align:start position:0% +way is very important chemical processes +that's true too but oftentimes we you + + align:start position:0% +that's true too but oftentimes we you + + + align:start position:0% +that's true too but oftentimes we you +can make choices in model formulation + + align:start position:0% +can make choices in model formulation + + + align:start position:0% +can make choices in model formulation +right like how you try to control the + + align:start position:0% +right like how you try to control the + + + align:start position:0% +right like how you try to control the +process that can ease the ease those + + align:start position:0% +process that can ease the ease those + + + align:start position:0% +process that can ease the ease those +constraints right if I had some + + align:start position:0% +constraints right if I had some + + + align:start position:0% +constraints right if I had some +controller it doesn't control in an + + align:start position:0% +controller it doesn't control in an + + + align:start position:0% +controller it doesn't control in an +instantaneous fashion even if it's a + + align:start position:0% +instantaneous fashion even if it's a + + + align:start position:0% +instantaneous fashion even if it's a +very high bandwidth controller so finite + + align:start position:0% +very high bandwidth controller so finite + + + align:start position:0% +very high bandwidth controller so finite +time for signals to propagate there's + + align:start position:0% +time for signals to propagate there's + + + align:start position:0% +time for signals to propagate there's +dynamics associated with the controller + + align:start position:0% +dynamics associated with the controller + + + align:start position:0% +dynamics associated with the controller +that can convert that da system into a + + align:start position:0% +that can convert that da system into a + + + align:start position:0% +that can convert that da system into a +system of Odie's for example then you + + align:start position:0% +system of Odie's for example then you + + + align:start position:0% +system of Odie's for example then you +don't have they may be stiff Odie's okay + + align:start position:0% +don't have they may be stiff Odie's okay + + + align:start position:0% +don't have they may be stiff Odie's okay +days are the limit of sort of infinite + + align:start position:0% +days are the limit of sort of infinite + + + align:start position:0% +days are the limit of sort of infinite +stiffness in Odie's but they're not they + + align:start position:0% +stiffness in Odie's but they're not they + + + align:start position:0% +stiffness in Odie's but they're not they +may not be as troublesome to solve as + + align:start position:0% +may not be as troublesome to solve as + + + align:start position:0% +may not be as troublesome to solve as +the da e system would be okay it's about + + align:start position:0% +the da e system would be okay it's about + + + align:start position:0% +the da e system would be okay it's about +model formulation okay can I can I talk + + align:start position:0% +model formulation okay can I can I talk + + + align:start position:0% +model formulation okay can I can I talk +briefly about PD es is that okay I'll + + align:start position:0% +briefly about PD es is that okay I'll + + + align:start position:0% +briefly about PD es is that okay I'll +tell you it tell you a bit about I like + + align:start position:0% +tell you it tell you a bit about I like + + + align:start position:0% +tell you it tell you a bit about I like +this finite volume method I think is + + align:start position:0% +this finite volume method I think is + + + align:start position:0% +this finite volume method I think is +very interesting okay you've got some + + align:start position:0% +very interesting okay you've got some + + + align:start position:0% +very interesting okay you've got some +notes on it I think I like it because I + + align:start position:0% +notes on it I think I like it because I + + + align:start position:0% +notes on it I think I like it because I +think it comes very naturally actually + + align:start position:0% +think it comes very naturally actually + + + align:start position:0% +think it comes very naturally actually +to chemical engineers because the + + align:start position:0% +to chemical engineers because the + + + align:start position:0% +to chemical engineers because the +problems we like to solve are of the + + align:start position:0% +problems we like to solve are of the + + + align:start position:0% +problems we like to solve are of the +type that finite finite volume eats for + + align:start position:0% +type that finite finite volume eats for + + + align:start position:0% +type that finite finite volume eats for +breakfast okay these are problems of + + align:start position:0% +breakfast okay these are problems of + + + align:start position:0% +breakfast okay these are problems of +conservation okay so we have a conserved + + align:start position:0% +conservation okay so we have a conserved + + + align:start position:0% +conservation okay so we have a conserved +quantity B right Saladin uses isn't in + + align:start position:0% +quantity B right Saladin uses isn't in + + + align:start position:0% +quantity B right Saladin uses isn't in +his book the new version still uses bees + + align:start position:0% +his book the new version still uses bees + + + align:start position:0% +his book the new version still uses bees +for me right so the time rate of change + + align:start position:0% +for me right so the time rate of change + + + align:start position:0% +for me right so the time rate of change +of B is equal to minus the gradient in + + align:start position:0% +of B is equal to minus the gradient in + + + align:start position:0% +of B is equal to minus the gradient in +the flux plus some I don't know some + + align:start position:0% +the flux plus some I don't know some + + + align:start position:0% +the flux plus some I don't know some +volumetric change maybe a reaction maybe + + align:start position:0% +volumetric change maybe a reaction maybe + + + align:start position:0% +volumetric change maybe a reaction maybe +there's some injection somewhere of mass + + align:start position:0% +there's some injection somewhere of mass + + + align:start position:0% +there's some injection somewhere of mass +or momentum or you know it's some source + + align:start position:0% +or momentum or you know it's some source + + + align:start position:0% +or momentum or you know it's some source +okay and our numerical solution + + align:start position:0% +okay and our numerical solution + + + align:start position:0% +okay and our numerical solution +oftentimes we would like it to also + + align:start position:0% +oftentimes we would like it to also + + + align:start position:0% +oftentimes we would like it to also +conserve B right conserve mass conserve + + align:start position:0% +conserve B right conserve mass conserve + + + align:start position:0% +conserve B right conserve mass conserve +momentum conserve energy conserve + + align:start position:0% +momentum conserve energy conserve + + + align:start position:0% +momentum conserve energy conserve +species these collocation methods in + + align:start position:0% +species these collocation methods in + + + align:start position:0% +species these collocation methods in +general a relaxation methods in general + + align:start position:0% +general a relaxation methods in general + + + align:start position:0% +general a relaxation methods in general +don't do that okay they're not designed + + align:start position:0% +don't do that okay they're not designed + + + align:start position:0% +don't do that okay they're not designed +to do that you might be able to + + align:start position:0% +to do that you might be able to + + + align:start position:0% +to do that you might be able to +construct for example basis functions + + align:start position:0% +construct for example basis functions + + + align:start position:0% +construct for example basis functions +that have that property that they will + + align:start position:0% +that have that property that they will + + + align:start position:0% +that have that property that they will +satisfy conservation okay you might be + + align:start position:0% +satisfy conservation okay you might be + + + align:start position:0% +satisfy conservation okay you might be +able to construct certain meshing + + align:start position:0% +able to construct certain meshing + + + align:start position:0% +able to construct certain meshing +methods + + align:start position:0% +methods + + + align:start position:0% +methods +okay certain collocation methods and + + align:start position:0% +okay certain collocation methods and + + + align:start position:0% +okay certain collocation methods and +this is one of them the finite volume + + align:start position:0% +this is one of them the finite volume + + + align:start position:0% +this is one of them the finite volume +method that respects conservation and + + align:start position:0% +method that respects conservation and + + + align:start position:0% +method that respects conservation and +here's how you do it okay so you worked + + align:start position:0% +here's how you do it okay so you worked + + + align:start position:0% +here's how you do it okay so you worked +you worked really hard and transport to + + align:start position:0% +you worked really hard and transport to + + + align:start position:0% +you worked really hard and transport to +derive these differential forms of the + + align:start position:0% +derive these differential forms of the + + + align:start position:0% +derive these differential forms of the +transport equations but finite volume + + align:start position:0% +transport equations but finite volume + + + align:start position:0% +transport equations but finite volume +actually likes the integral form so you + + align:start position:0% +actually likes the integral form so you + + + align:start position:0% +actually likes the integral form so you +got to go back okay so you got to take + + align:start position:0% +got to go back okay so you got to take + + + align:start position:0% +got to go back okay so you got to take +the integral of these equations over + + align:start position:0% +the integral of these equations over + + + align:start position:0% +the integral of these equations over +some volume V and then the time + + align:start position:0% +some volume V and then the time + + + align:start position:0% +some volume V and then the time +derivative okay of the amount of B in + + align:start position:0% +derivative okay of the amount of B in + + + align:start position:0% +derivative okay of the amount of B in +this volume is related to the flux of V + + align:start position:0% +this volume is related to the flux of V + + + align:start position:0% +this volume is related to the flux of V +of B through the surfaces of that volume + + align:start position:0% +of B through the surfaces of that volume + + + align:start position:0% +of B through the surfaces of that volume +plus the amount of generation or + + align:start position:0% +plus the amount of generation or + + + align:start position:0% +plus the amount of generation or +consumption of the conserved quantity + + align:start position:0% +consumption of the conserved quantity + + + align:start position:0% +consumption of the conserved quantity +within that volume V right and this + + align:start position:0% +within that volume V right and this + + + align:start position:0% +within that volume V right and this +volume is my finite volume I take the + + align:start position:0% +volume is my finite volume I take the + + + align:start position:0% +volume is my finite volume I take the +domain of interest and I chop it up into + + align:start position:0% +domain of interest and I chop it up into + + + align:start position:0% +domain of interest and I chop it up into +all these little volumes okay and then I + + align:start position:0% +all these little volumes okay and then I + + + align:start position:0% +all these little volumes okay and then I +just need to conserve B within that + + align:start position:0% +just need to conserve B within that + + + align:start position:0% +just need to conserve B within that +volume so I have the class you know the + + align:start position:0% +volume so I have the class you know the + + + align:start position:0% +volume so I have the class you know the +first equation you learned in chemical + + align:start position:0% +first equation you learned in chemical + + + align:start position:0% +first equation you learned in chemical +engineering right the amount of + + align:start position:0% +engineering right the amount of + + + align:start position:0% +engineering right the amount of +accumulation of the conserved quantity + + align:start position:0% +accumulation of the conserved quantity + + + align:start position:0% +accumulation of the conserved quantity +is related to the fluxes in and out of + + align:start position:0% +is related to the fluxes in and out of + + + align:start position:0% +is related to the fluxes in and out of +the control volume plus the amount of + + align:start position:0% +the control volume plus the amount of + + + align:start position:0% +the control volume plus the amount of +generation or consumption within the + + align:start position:0% +generation or consumption within the + + + align:start position:0% +generation or consumption within the +control arms this comes very naturally + + align:start position:0% +control arms this comes very naturally + + + align:start position:0% +control arms this comes very naturally +to chemical engineers it fits perfectly + + align:start position:0% +to chemical engineers it fits perfectly + + + align:start position:0% +to chemical engineers it fits perfectly +in the problems we like to solve yeah + + align:start position:0% + + + + align:start position:0% + +well it all depends on how we choose to + + align:start position:0% +well it all depends on how we choose to + + + align:start position:0% +well it all depends on how we choose to +write J actually right so is J the flux + + align:start position:0% +write J actually right so is J the flux + + + align:start position:0% +write J actually right so is J the flux +into or out of this volume so I won't i + + align:start position:0% +into or out of this volume so I won't i + + + align:start position:0% +into or out of this volume so I won't i +won't i won't prescribe that here + + align:start position:0% +won't i won't prescribe that here + + + align:start position:0% +won't i won't prescribe that here +right okay it depends on what you chose + + align:start position:0% +right okay it depends on what you chose + + + align:start position:0% +right okay it depends on what you chose +as the flux so maybe I don't know what + + align:start position:0% +as the flux so maybe I don't know what + + + align:start position:0% +as the flux so maybe I don't know what +does Dean writes the stress tensor with + + align:start position:0% +does Dean writes the stress tensor with + + + align:start position:0% +does Dean writes the stress tensor with +the opposite sign of like bird Stewart + + align:start position:0% +the opposite sign of like bird Stewart + + + align:start position:0% +the opposite sign of like bird Stewart +and Lightfoot right so these guys that's + + align:start position:0% +and Lightfoot right so these guys that's + + + align:start position:0% +and Lightfoot right so these guys that's +the flux of momentum right they choose a + + align:start position:0% +the flux of momentum right they choose a + + + align:start position:0% +the flux of momentum right they choose a +sign and then the normals have to + + align:start position:0% +sign and then the normals have to + + + align:start position:0% +sign and then the normals have to +respect that sign doesn't really matter + + align:start position:0% +respect that sign doesn't really matter + + + align:start position:0% +respect that sign doesn't really matter +the physics doesn't care okay you just + + align:start position:0% +the physics doesn't care okay you just + + + align:start position:0% +the physics doesn't care okay you just +have to choose the flux in the right + + align:start position:0% +have to choose the flux in the right + + + align:start position:0% +have to choose the flux in the right +direction if we think of J is the flux + + align:start position:0% +direction if we think of J is the flux + + + align:start position:0% +direction if we think of J is the flux +into the volume and you should point in + + align:start position:0% +into the volume and you should point in + + + align:start position:0% +into the volume and you should point in +okay right okay so you have this + + align:start position:0% +okay right okay so you have this + + + align:start position:0% +okay right okay so you have this +conservation equation you've got to + + align:start position:0% +conservation equation you've got to + + + align:start position:0% +conservation equation you've got to +solve for each of your finite volumes + + align:start position:0% +solve for each of your finite volumes + + + align:start position:0% +solve for each of your finite volumes +and the finite volumes are coupled + + align:start position:0% +and the finite volumes are coupled + + + align:start position:0% +and the finite volumes are coupled +together because the flux out of one + + align:start position:0% +together because the flux out of one + + + align:start position:0% +together because the flux out of one +volume is a flux into another volume + + align:start position:0% +volume is a flux into another volume + + + align:start position:0% +volume is a flux into another volume +right so you can think of these volumes + + align:start position:0% +right so you can think of these volumes + + + align:start position:0% +right so you can think of these volumes +as being little cstr's right they're all + + align:start position:0% +as being little cstr's right they're all + + + align:start position:0% +as being little cstr's right they're all +sitting next to each other and they're + + align:start position:0% +sitting next to each other and they're + + + align:start position:0% +sitting next to each other and they're +all linked together by these volumetric + + align:start position:0% +all linked together by these volumetric + + + align:start position:0% +all linked together by these volumetric +flows from one to another and that's in + + align:start position:0% +flows from one to another and that's in + + + align:start position:0% +flows from one to another and that's in +fact what they are right the key is how + + align:start position:0% +fact what they are right the key is how + + + align:start position:0% +fact what they are right the key is how +do i model these fluxes basically right + + align:start position:0% +do i model these fluxes basically right + + + align:start position:0% +do i model these fluxes basically right +the accuracy the method is gonna be set + + align:start position:0% +the accuracy the method is gonna be set + + + align:start position:0% +the accuracy the method is gonna be set +by how big a volume am I gonna model + + align:start position:0% +by how big a volume am I gonna model + + + align:start position:0% +by how big a volume am I gonna model +right can't have infinitely small + + align:start position:0% +right can't have infinitely small + + + align:start position:0% +right can't have infinitely small +volumes gonna be too many of them in my + + align:start position:0% +volumes gonna be too many of them in my + + + align:start position:0% +volumes gonna be too many of them in my +domain to solve the problem accurately + + align:start position:0% +domain to solve the problem accurately + + + align:start position:0% +domain to solve the problem accurately +okay and then do I have good models for + + align:start position:0% +okay and then do I have good models for + + + align:start position:0% +okay and then do I have good models for +these fluxes you think about these terms + + align:start position:0% +these fluxes you think about these terms + + + align:start position:0% +these fluxes you think about these terms +in this way okay so sometimes it's + + align:start position:0% +in this way okay so sometimes it's + + + align:start position:0% +in this way okay so sometimes it's +useful so there's big be the amount of B + + align:start position:0% +useful so there's big be the amount of B + + + align:start position:0% +useful so there's big be the amount of B +in the volume is like the volume times + + align:start position:0% +in the volume is like the volume times + + + align:start position:0% +in the volume is like the volume times +the density of B the volumetric density + + align:start position:0% +the density of B the volumetric density + + + align:start position:0% +the density of B the volumetric density +of B and the volume right the average + + align:start position:0% +of B and the volume right the average + + + align:start position:0% +of B and the volume right the average +density in the volume R is like the + + align:start position:0% +density in the volume R is like the + + + align:start position:0% +density in the volume R is like the +volume multiplied by the average rate of + + align:start position:0% +volume multiplied by the average rate of + + + align:start position:0% +volume multiplied by the average rate of +generation or consumption okay F is the + + align:start position:0% +generation or consumption okay F is the + + + align:start position:0% +generation or consumption okay F is the +flux in or out it's the sum over all the + + align:start position:0% +flux in or out it's the sum over all the + + + align:start position:0% +flux in or out it's the sum over all the +phases of the flux through each of the + + align:start position:0% +phases of the flux through each of the + + + align:start position:0% +phases of the flux through each of the +phases which is the area of the face + + align:start position:0% +phases which is the area of the face + + + align:start position:0% +phases which is the area of the face +multiplied by the average flux through + + align:start position:0% +multiplied by the average flux through + + + align:start position:0% +multiplied by the average flux through +the face so this is the normal to the + + align:start position:0% +the face so this is the normal to the + + + align:start position:0% +the face so this is the normal to the +face and this is the flux through the + + align:start position:0% +face and this is the flux through the + + + align:start position:0% +face and this is the flux through the +face okay and so I just are gonna solve + + align:start position:0% +face okay and so I just are gonna solve + + + align:start position:0% +face okay and so I just are gonna solve +this equation right I try to figure out + + align:start position:0% +this equation right I try to figure out + + + align:start position:0% +this equation right I try to figure out +in each volume what's the average be + + align:start position:0% +in each volume what's the average be + + + align:start position:0% +in each volume what's the average be +okay that's what this tells me right + + align:start position:0% +okay that's what this tells me right + + + align:start position:0% +okay that's what this tells me right +well on average what is B on average + + align:start position:0% +well on average what is B on average + + + align:start position:0% +well on average what is B on average +what is the concentration on average + + align:start position:0% +what is the concentration on average + + + align:start position:0% +what is the concentration on average +what is the amount of momentum on + + align:start position:0% +what is the amount of momentum on + + + align:start position:0% +what is the amount of momentum on +average what is the total energy right + + align:start position:0% +average what is the total energy right + + + align:start position:0% +average what is the total energy right +it's fine + + align:start position:0% +it's fine + + + align:start position:0% +it's fine +okay so finite volume very simple okay + + align:start position:0% +okay so finite volume very simple okay + + + align:start position:0% +okay so finite volume very simple okay +what's nice about it + + align:start position:0% +what's nice about it + + + align:start position:0% +what's nice about it +well you know it's really suitable to + + align:start position:0% +well you know it's really suitable to + + + align:start position:0% +well you know it's really suitable to +any sort of geometry we want to look at + + align:start position:0% +any sort of geometry we want to look at + + + align:start position:0% +any sort of geometry we want to look at +we want to solve this equation say in + + align:start position:0% +we want to solve this equation say in + + + align:start position:0% +we want to solve this equation say in +this square domain we divide the domain + + align:start position:0% +this square domain we divide the domain + + + align:start position:0% +this square domain we divide the domain +up into a bunch of little square volumes + + align:start position:0% +up into a bunch of little square volumes + + + align:start position:0% +up into a bunch of little square volumes +and in each volume we just make sure + + align:start position:0% +and in each volume we just make sure + + + align:start position:0% +and in each volume we just make sure +that the amount of this be right + + align:start position:0% +that the amount of this be right + + + align:start position:0% +that the amount of this be right +balances the fluxes coming through the + + align:start position:0% +balances the fluxes coming through the + + + align:start position:0% +balances the fluxes coming through the +volume and the amount of consumption or + + align:start position:0% +volume and the amount of consumption or + + + align:start position:0% +volume and the amount of consumption or +generation of that quantity within the + + align:start position:0% +generation of that quantity within the + + + align:start position:0% +generation of that quantity within the +volume but it didn't have to be a square + + align:start position:0% +volume but it didn't have to be a square + + + align:start position:0% +volume but it didn't have to be a square +domain right square domain it's okay but + + align:start position:0% +domain right square domain it's okay but + + + align:start position:0% +domain right square domain it's okay but +maybe I want to solve it on some + + align:start position:0% +maybe I want to solve it on some + + + align:start position:0% +maybe I want to solve it on some +circular domain well I can divide that + + align:start position:0% +circular domain well I can divide that + + + align:start position:0% +circular domain well I can divide that +up into volumes too and actually this + + align:start position:0% +up into volumes too and actually this + + + align:start position:0% +up into volumes too and actually this +these equations are the same right they + + align:start position:0% +these equations are the same right they + + + align:start position:0% +these equations are the same right they +look identical I just got to calculate + + align:start position:0% +look identical I just got to calculate + + + align:start position:0% +look identical I just got to calculate +the flux through each of the phases okay + + align:start position:0% +the flux through each of the phases okay + + + align:start position:0% +the flux through each of the phases okay +but maybe I'm interested in I don't know + + align:start position:0% +but maybe I'm interested in I don't know + + + align:start position:0% +but maybe I'm interested in I don't know +pollution and one of the Great Lakes and + + align:start position:0% +pollution and one of the Great Lakes and + + + align:start position:0% +pollution and one of the Great Lakes and +I want to know how concentration is some + + align:start position:0% +I want to know how concentration is some + + + align:start position:0% +I want to know how concentration is some +pollutant is trans transformed well + + align:start position:0% +pollutant is trans transformed well + + + align:start position:0% +pollutant is trans transformed well +divide this up into a bunch of little + + align:start position:0% +divide this up into a bunch of little + + + align:start position:0% +divide this up into a bunch of little +volumes too and now I got to calculate + + align:start position:0% +volumes too and now I got to calculate + + + align:start position:0% +volumes too and now I got to calculate +the flux through each of these phases + + align:start position:0% +the flux through each of these phases + + + align:start position:0% +the flux through each of these phases +and that links all these domains + + align:start position:0% +and that links all these domains + + + align:start position:0% +and that links all these domains +together okay maybe I'm interested in + + align:start position:0% +together okay maybe I'm interested in + + + align:start position:0% +together okay maybe I'm interested in +transport within some porous medium say + + align:start position:0% +transport within some porous medium say + + + align:start position:0% +transport within some porous medium say +a bone I think it's someone's hip joint + + align:start position:0% +a bone I think it's someone's hip joint + + + align:start position:0% +a bone I think it's someone's hip joint +here okay well I divide that up into a + + align:start position:0% +here okay well I divide that up into a + + + align:start position:0% +here okay well I divide that up into a +bunch of volumes and I still sound solve + + align:start position:0% +bunch of volumes and I still sound solve + + + align:start position:0% +bunch of volumes and I still sound solve +the exact same conservation equation so + + align:start position:0% +the exact same conservation equation so + + + align:start position:0% +the exact same conservation equation so +I'm sort of decoupled the problem of + + align:start position:0% +I'm sort of decoupled the problem of + + + align:start position:0% +I'm sort of decoupled the problem of +meshing and equations okay the governing + + align:start position:0% +meshing and equations okay the governing + + + align:start position:0% +meshing and equations okay the governing +equations associated with the meshes as + + align:start position:0% +equations associated with the meshes as + + + align:start position:0% +equations associated with the meshes as +long as I have a way to divide the + + align:start position:0% +long as I have a way to divide the + + + align:start position:0% +long as I have a way to divide the +domain up may be very complicated okay + + align:start position:0% +domain up may be very complicated okay + + + align:start position:0% +domain up may be very complicated okay +I'm gonna go ask a buddy in applied math + + align:start position:0% +I'm gonna go ask a buddy in applied math + + + align:start position:0% +I'm gonna go ask a buddy in applied math +to do that + + align:start position:0% +to do that + + + align:start position:0% +to do that +well I'm gonna come to them with the + + align:start position:0% +well I'm gonna come to them with the + + + align:start position:0% +well I'm gonna come to them with the +right engineering equations for each of + + align:start position:0% +right engineering equations for each of + + + align:start position:0% +right engineering equations for each of +those domains a little equation for a + + align:start position:0% +those domains a little equation for a + + + align:start position:0% +those domains a little equation for a +CSTR okay it turns out this you know one + + align:start position:0% +CSTR okay it turns out this you know one + + + align:start position:0% +CSTR okay it turns out this you know one +of the one one of the most common say + + align:start position:0% +of the one one of the most common say + + + align:start position:0% +of the one one of the most common say +fluid mechanical codes out there that + + align:start position:0% +fluid mechanical codes out there that + + + align:start position:0% +fluid mechanical codes out there that +people use now is open foam okay this is + + align:start position:0% +people use now is open foam okay this is + + + align:start position:0% +people use now is open foam okay this is +very common + + align:start position:0% +very common + + + align:start position:0% +very common +lots of people use it it's very general + + align:start position:0% +lots of people use it it's very general + + + align:start position:0% +lots of people use it it's very general +solver does finite volume that's the + + align:start position:0% +solver does finite volume that's the + + + align:start position:0% +solver does finite volume that's the +method it chooses to use why does it + + align:start position:0% +method it chooses to use why does it + + + align:start position:0% +method it chooses to use why does it +choose to use because it wants to + + align:start position:0% +choose to use because it wants to + + + align:start position:0% +choose to use because it wants to +convert conserve momentum okay i + + align:start position:0% +convert conserve momentum okay i + + + align:start position:0% +convert conserve momentum okay i +guaranteed momentum conservation can't + + align:start position:0% +guaranteed momentum conservation can't + + + align:start position:0% +guaranteed momentum conservation can't +lose momentum can't lose energy okay + + align:start position:0% +lose momentum can't lose energy okay + + + align:start position:0% +lose momentum can't lose energy okay +can't lose mass I just have to pass the + + align:start position:0% +can't lose mass I just have to pass the + + + align:start position:0% +can't lose mass I just have to pass the +right amount between each of these + + align:start position:0% +right amount between each of these + + + align:start position:0% +right amount between each of these +spaces as long as my calculation of that + + align:start position:0% +spaces as long as my calculation of that + + + align:start position:0% +spaces as long as my calculation of that +is + + align:start position:0% +is + + + align:start position:0% +is +accurate I've conserved the quantity it + + align:start position:0% +accurate I've conserved the quantity it + + + align:start position:0% +accurate I've conserved the quantity it +never evaporates find a difference + + align:start position:0% +never evaporates find a difference + + + align:start position:0% +never evaporates find a difference +finite element different basis set + + align:start position:0% +finite element different basis set + + + align:start position:0% +finite element different basis set +expansions they they will have this + + align:start position:0% +expansions they they will have this + + + align:start position:0% +expansions they they will have this +problem that at low levels of accuracy + + align:start position:0% +problem that at low levels of accuracy + + + align:start position:0% +problem that at low levels of accuracy +you can have sort of artificial constant + + align:start position:0% +you can have sort of artificial constant + + + align:start position:0% +you can have sort of artificial constant +consumption of save the quantity or + + align:start position:0% +consumption of save the quantity or + + + align:start position:0% +consumption of save the quantity or +artificial production of the quantity + + align:start position:0% +artificial production of the quantity + + + align:start position:0% +artificial production of the quantity +conserved quantity of interest okay so + + align:start position:0% +conserved quantity of interest okay so + + + align:start position:0% +conserved quantity of interest okay so +this is gonna be very nice way to solve + + align:start position:0% +this is gonna be very nice way to solve + + + align:start position:0% +this is gonna be very nice way to solve +these problems too + + align:start position:0% +these problems too + + + align:start position:0% +these problems too +it's another relaxation method it's a + + align:start position:0% +it's another relaxation method it's a + + + align:start position:0% +it's another relaxation method it's a +type of collocation I divide the domain + + align:start position:0% +type of collocation I divide the domain + + + align:start position:0% +type of collocation I divide the domain +up right and I try to satisfy + + align:start position:0% +up right and I try to satisfy + + + align:start position:0% +up right and I try to satisfy +conservation equations on each of these + + align:start position:0% +conservation equations on each of these + + + align:start position:0% +conservation equations on each of these +little volumes since finite volume okay + + align:start position:0% +little volumes since finite volume okay + + + align:start position:0% +little volumes since finite volume okay +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so how do you solve Pease by hand or + + align:start position:0% +so how do you solve Pease by hand or + + + align:start position:0% +so how do you solve Pease by hand or +write your own code there's a nice + + align:start position:0% +write your own code there's a nice + + + align:start position:0% +write your own code there's a nice +little tutorial here we'll see how far + + align:start position:0% +little tutorial here we'll see how far + + + align:start position:0% +little tutorial here we'll see how far +we're able to get through it before I + + align:start position:0% +we're able to get through it before I + + + align:start position:0% +we're able to get through it before I +gotta give you guys your cards but I'll + + align:start position:0% +gotta give you guys your cards but I'll + + + align:start position:0% +gotta give you guys your cards but I'll +illustrate some key points okay that I + + align:start position:0% +illustrate some key points okay that I + + + align:start position:0% +illustrate some key points okay that I +think are really important so step one + + align:start position:0% +think are really important so step one + + + align:start position:0% +think are really important so step one +okay no matter what what method you + + align:start position:0% +okay no matter what what method you + + + align:start position:0% +okay no matter what what method you +choose right whether you choose + + align:start position:0% +choose right whether you choose + + + align:start position:0% +choose right whether you choose +collocation whether you choose galerkin + + align:start position:0% +collocation whether you choose galerkin + + + align:start position:0% +collocation whether you choose galerkin +right whether using basis sets or you're + + align:start position:0% +right whether using basis sets or you're + + + align:start position:0% +right whether using basis sets or you're +using finite elements or finite volumes + + align:start position:0% +using finite elements or finite volumes + + + align:start position:0% +using finite elements or finite volumes +you've got some domain you're trying to + + align:start position:0% +you've got some domain you're trying to + + + align:start position:0% +you've got some domain you're trying to +solve your PDE and then you've got to + + align:start position:0% +solve your PDE and then you've got to + + + align:start position:0% +solve your PDE and then you've got to +discretize it okay you've got to figure + + align:start position:0% +discretize it okay you've got to figure + + + align:start position:0% +discretize it okay you've got to figure +out how to decompose the domain so for + + align:start position:0% +out how to decompose the domain so for + + + align:start position:0% +out how to decompose the domain so for +finite differences you might decompose + + align:start position:0% +finite differences you might decompose + + + align:start position:0% +finite differences you might decompose +it into a series of nodes at which you + + align:start position:0% +it into a series of nodes at which you + + + align:start position:0% +it into a series of nodes at which you +want to know the value of your function + + align:start position:0% +want to know the value of your function + + + align:start position:0% +want to know the value of your function +whatever that function is for finite + + align:start position:0% +whatever that function is for finite + + + align:start position:0% +whatever that function is for finite +volume you decompose it into cells in + + align:start position:0% +volume you decompose it into cells in + + + align:start position:0% +volume you decompose it into cells in +which you would like to know the average + + align:start position:0% +which you would like to know the average + + + align:start position:0% +which you would like to know the average +value of your conserved quantity for + + align:start position:0% +value of your conserved quantity for + + + align:start position:0% +value of your conserved quantity for +finite elements right you divide the + + align:start position:0% +finite elements right you divide the + + + align:start position:0% +finite elements right you divide the +domain up into into some points across + + align:start position:0% +domain up into into some points across + + + align:start position:0% +domain up into into some points across +which low-salt local basis functions + + align:start position:0% +which low-salt local basis functions + + + align:start position:0% +which low-salt local basis functions +span right the region you would like to + + align:start position:0% +span right the region you would like to + + + align:start position:0% +span right the region you would like to +know the weighting of these local basis + + align:start position:0% +know the weighting of these local basis + + + align:start position:0% +know the weighting of these local basis +functions near each of these points okay + + align:start position:0% +functions near each of these points okay + + + align:start position:0% +functions near each of these points okay +but you've got to divide the domain up + + align:start position:0% +but you've got to divide the domain up + + + align:start position:0% +but you've got to divide the domain up +and the most important thing okay is you + + align:start position:0% +and the most important thing okay is you + + + align:start position:0% +and the most important thing okay is you +always choose the spacing the nodes okay + + align:start position:0% +always choose the spacing the nodes okay + + + align:start position:0% +always choose the spacing the nodes okay +there are the dimensions of the cells to + + align:start position:0% +there are the dimensions of the cells to + + + align:start position:0% +there are the dimensions of the cells to +match the physics a very natural thing + + align:start position:0% +match the physics a very natural thing + + + align:start position:0% +match the physics a very natural thing +to want to do is to pick same say I've + + align:start position:0% +to want to do is to pick same say I've + + + align:start position:0% +to want to do is to pick same say I've +got this square grid is to pick the + + align:start position:0% +got this square grid is to pick the + + + align:start position:0% +got this square grid is to pick the +number of grid points to discretize with + + align:start position:0% +number of grid points to discretize with + + + align:start position:0% +number of grid points to discretize with +right say I'm gonna use a hundred points + + align:start position:0% +right say I'm gonna use a hundred points + + + align:start position:0% +right say I'm gonna use a hundred points +in this dimension and a hundred points + + align:start position:0% +in this dimension and a hundred points + + + align:start position:0% +in this dimension and a hundred points +in that dimension actually tells me + + align:start position:0% +in that dimension actually tells me + + + align:start position:0% +in that dimension actually tells me +nothing that's an irrelevant number okay + + align:start position:0% +nothing that's an irrelevant number okay + + + align:start position:0% +nothing that's an irrelevant number okay +the physics has no idea how many grid + + align:start position:0% +the physics has no idea how many grid + + + align:start position:0% +the physics has no idea how many grid +nodes you put in there + + align:start position:0% +nodes you put in there + + + align:start position:0% +nodes you put in there +doesn't care okay there are length + + align:start position:0% +doesn't care okay there are length + + + align:start position:0% +doesn't care okay there are length +scales that are intrinsic to the problem + + align:start position:0% +scales that are intrinsic to the problem + + + align:start position:0% +scales that are intrinsic to the problem +you're trying to study and the + + align:start position:0% +you're trying to study and the + + + align:start position:0% +you're trying to study and the +discretization should resolve those + + align:start position:0% +discretization should resolve those + + + align:start position:0% +discretization should resolve those +physically relevant length scales okay + + align:start position:0% +physically relevant length scales okay + + + align:start position:0% +physically relevant length scales okay +so it might be the case that I only need + + align:start position:0% +so it might be the case that I only need + + + align:start position:0% +so it might be the case that I only need +a resolution of you know one part in ten + + align:start position:0% +a resolution of you know one part in ten + + + align:start position:0% +a resolution of you know one part in ten +along this dimension and one part in ten + + align:start position:0% +along this dimension and one part in ten + + + align:start position:0% +along this dimension and one part in ten +along this dimension because the physics + + align:start position:0% +along this dimension because the physics + + + align:start position:0% +along this dimension because the physics +are such that that's that's good to get + + align:start position:0% +are such that that's that's good to get + + + align:start position:0% +are such that that's that's good to get +a description of the solution to this + + align:start position:0% +a description of the solution to this + + + align:start position:0% +a description of the solution to this +problem it might be that I need one part + + align:start position:0% +problem it might be that I need one part + + + align:start position:0% +problem it might be that I need one part +in a million in this dimension and one + + align:start position:0% +in a million in this dimension and one + + + align:start position:0% +in a million in this dimension and one +part in ten in that dimension because + + align:start position:0% +part in ten in that dimension because + + + align:start position:0% +part in ten in that dimension because +the physics are that way okay so you + + align:start position:0% +the physics are that way okay so you + + + align:start position:0% +the physics are that way okay so you +really want to think about length scales + + align:start position:0% +really want to think about length scales + + + align:start position:0% +really want to think about length scales +not numbers of nodes is a very common + + align:start position:0% +not numbers of nodes is a very common + + + align:start position:0% +not numbers of nodes is a very common +mistake you say oh I a hundred and a + + align:start position:0% +mistake you say oh I a hundred and a + + + align:start position:0% +mistake you say oh I a hundred and a +hundred that makes sense or ten in ten + + align:start position:0% +hundred that makes sense or ten in ten + + + align:start position:0% +hundred that makes sense or ten in ten +or you know you pick these randomly but + + align:start position:0% +or you know you pick these randomly but + + + align:start position:0% +or you know you pick these randomly but +you won't think about physics instead + + align:start position:0% +you won't think about physics instead + + + align:start position:0% +you won't think about physics instead +here's a good example right this is my + + align:start position:0% +here's a good example right this is my + + + align:start position:0% +here's a good example right this is my +phone you'll solve a problem like this + + align:start position:0% +phone you'll solve a problem like this + + + align:start position:0% +phone you'll solve a problem like this +you already saw it in some sense in the + + align:start position:0% +you already saw it in some sense in the + + + align:start position:0% +you already saw it in some sense in the +finite finite element or COMSOL tutorial + + align:start position:0% +finite finite element or COMSOL tutorial + + + align:start position:0% +finite finite element or COMSOL tutorial +all right there's a little drug patch + + align:start position:0% +all right there's a little drug patch + + + align:start position:0% +all right there's a little drug patch +here near this red zone all right it's + + align:start position:0% +here near this red zone all right it's + + + align:start position:0% +here near this red zone all right it's +leaking drug into a shear flow and it's + + align:start position:0% +leaking drug into a shear flow and it's + + + align:start position:0% +leaking drug into a shear flow and it's +all being infected down okay here's + + align:start position:0% +all being infected down okay here's + + + align:start position:0% +all being infected down okay here's +here's here's here's my solution to the + + align:start position:0% +here's here's here's my solution to the + + + align:start position:0% +here's here's here's my solution to the +problem I think is pretty good one + + align:start position:0% +problem I think is pretty good one + + + align:start position:0% +problem I think is pretty good one +here's a solution from when I taught the + + align:start position:0% +here's a solution from when I taught the + + + align:start position:0% +here's a solution from when I taught the +course two years ago that the T is + + align:start position:0% +course two years ago that the T is + + + align:start position:0% +course two years ago that the T is +produced and I didn't I didn't talk with + + align:start position:0% +produced and I didn't I didn't talk with + + + align:start position:0% +produced and I didn't I didn't talk with +the TAS about this issue with length + + align:start position:0% +the TAS about this issue with length + + + align:start position:0% +the TAS about this issue with length +scales and it's it's sort of got the + + align:start position:0% +scales and it's it's sort of got the + + + align:start position:0% +scales and it's it's sort of got the +right structure you can see here's the + + align:start position:0% +right structure you can see here's the + + + align:start position:0% +right structure you can see here's the +patch and there's some advection and + + align:start position:0% +patch and there's some advection and + + + align:start position:0% +patch and there's some advection and +diffusion but it's it's not a very + + align:start position:0% +diffusion but it's it's not a very + + + align:start position:0% +diffusion but it's it's not a very +stable solution it turns out it's also + + align:start position:0% +stable solution it turns out it's also + + + align:start position:0% +stable solution it turns out it's also +not very accurate it doesn't reflect the + + align:start position:0% +not very accurate it doesn't reflect the + + + align:start position:0% +not very accurate it doesn't reflect the +essential physics and the point is + + align:start position:0% +essential physics and the point is + + + align:start position:0% +essential physics and the point is +actually the scales so here the patch + + align:start position:0% +actually the scales so here the patch + + + align:start position:0% +actually the scales so here the patch +was one centimeter in diameter okay and + + align:start position:0% +was one centimeter in diameter okay and + + + align:start position:0% +was one centimeter in diameter okay and +so here you got many centimeters along + + align:start position:0% +so here you got many centimeters along + + + align:start position:0% +so here you got many centimeters along +this direction where you get advection + + align:start position:0% +this direction where you get advection + + + align:start position:0% +this direction where you get advection +here you've got two centimeters in this + + align:start position:0% +here you've got two centimeters in this + + + align:start position:0% +here you've got two centimeters in this +direction but actually the solution it's + + align:start position:0% +direction but actually the solution it's + + + align:start position:0% +direction but actually the solution it's +really confined down to this small space + + align:start position:0% +really confined down to this small space + + + align:start position:0% +really confined down to this small space +right the physics all happens at + + align:start position:0% +right the physics all happens at + + + align:start position:0% +right the physics all happens at +fractions of a centimeter okay + + align:start position:0% +fractions of a centimeter okay + + + align:start position:0% +fractions of a centimeter okay +you took transport so you know that this + + align:start position:0% +you took transport so you know that this + + + align:start position:0% +you took transport so you know that this +is a problem in which there's a boundary + + align:start position:0% +is a problem in which there's a boundary + + + align:start position:0% +is a problem in which there's a boundary +layer and all the change in + + align:start position:0% +layer and all the change in + + + align:start position:0% +layer and all the change in +concentration is confined to that little + + align:start position:0% +concentration is confined to that little + + + align:start position:0% +concentration is confined to that little +boundary layer okay so really when you + + align:start position:0% +boundary layer okay so really when you + + + align:start position:0% +boundary layer okay so really when you +do your numerical solution you wanna do + + align:start position:0% +do your numerical solution you wanna do + + + align:start position:0% +do your numerical solution you wanna do +like like what's done up here now that + + align:start position:0% +like like what's done up here now that + + + align:start position:0% +like like what's done up here now that +lengths are made dimensionless on the + + align:start position:0% +lengths are made dimensionless on the + + + align:start position:0% +lengths are made dimensionless on the +width of the patch but they're you know + + align:start position:0% +width of the patch but they're you know + + + align:start position:0% +width of the patch but they're you know +you could think these is measured in + + align:start position:0% +you could think these is measured in + + + align:start position:0% +you could think these is measured in +centimeters but look at the dimension + + align:start position:0% +centimeters but look at the dimension + + + align:start position:0% +centimeters but look at the dimension +here + + align:start position:0% +here + + + align:start position:0% +here +right we need to resolve the solution + + align:start position:0% +right we need to resolve the solution + + + align:start position:0% +right we need to resolve the solution +down at the 0.1 centimeter and smaller + + align:start position:0% +down at the 0.1 centimeter and smaller + + + align:start position:0% +down at the 0.1 centimeter and smaller +scale I want to put all my little disk + + align:start position:0% +scale I want to put all my little disk + + + align:start position:0% +scale I want to put all my little disk +rotation or my nodes down here so they + + align:start position:0% +rotation or my nodes down here so they + + + align:start position:0% +rotation or my nodes down here so they +can see how the concentration field + + align:start position:0% +can see how the concentration field + + + align:start position:0% +can see how the concentration field +changes okay as a function of distance I + + align:start position:0% +changes okay as a function of distance I + + + align:start position:0% +changes okay as a function of distance I +have to know something about the physics + + align:start position:0% +have to know something about the physics + + + align:start position:0% +have to know something about the physics +to do that though okay can't just solve + + align:start position:0% +to do that though okay can't just solve + + + align:start position:0% +to do that though okay can't just solve +this blindly it may or may not be the + + align:start position:0% +this blindly it may or may not be the + + + align:start position:0% +this blindly it may or may not be the +case the calm saw recognizes the + + align:start position:0% +case the calm saw recognizes the + + + align:start position:0% +case the calm saw recognizes the +physical situation and Ramesh's your + + align:start position:0% +physical situation and Ramesh's your + + + align:start position:0% +physical situation and Ramesh's your +problem to put mesh points down where + + align:start position:0% +problem to put mesh points down where + + + align:start position:0% +problem to put mesh points down where +they matter okay it may do that it may + + align:start position:0% +they matter okay it may do that it may + + + align:start position:0% +they matter okay it may do that it may +not do that it just doesn't know people + + align:start position:0% +not do that it just doesn't know people + + + align:start position:0% +not do that it just doesn't know people +build heuristics to try to solve these + + align:start position:0% +build heuristics to try to solve these + + + align:start position:0% +build heuristics to try to solve these +rameshan problems but they may not + + align:start position:0% +rameshan problems but they may not + + + align:start position:0% +rameshan problems but they may not +always apply so it's good to understand + + align:start position:0% +always apply so it's good to understand + + + align:start position:0% +always apply so it's good to understand +the physics of the problem this rough + + align:start position:0% +the physics of the problem this rough + + + align:start position:0% +the physics of the problem this rough +patch problem this is a pretty common + + align:start position:0% +patch problem this is a pretty common + + + align:start position:0% +patch problem this is a pretty common +transport problem did the professor + + align:start position:0% +transport problem did the professor + + + align:start position:0% +transport problem did the professor +bazan give you guys a talk during your + + align:start position:0% +bazan give you guys a talk during your + + + align:start position:0% +bazan give you guys a talk during your +visit weekend was that this last year is + + align:start position:0% +visit weekend was that this last year is + + + align:start position:0% +visit weekend was that this last year is +that two years ago it was two years ago + + align:start position:0% +that two years ago it was two years ago + + + align:start position:0% +that two years ago it was two years ago +he does problems with bromine flow + + align:start position:0% +he does problems with bromine flow + + + align:start position:0% +he does problems with bromine flow +batteries right and they work exactly + + align:start position:0% +batteries right and they work exactly + + + align:start position:0% +batteries right and they work exactly +this way have flow of a you have flow of + + align:start position:0% +this way have flow of a you have flow of + + + align:start position:0% +this way have flow of a you have flow of +bromine in an electrochemical reaction + + align:start position:0% +bromine in an electrochemical reaction + + + align:start position:0% +bromine in an electrochemical reaction +takes place at the surface this entire + + align:start position:0% +takes place at the surface this entire + + + align:start position:0% +takes place at the surface this entire +thing is premise on the fact that you + + align:start position:0% +thing is premise on the fact that you + + + align:start position:0% +thing is premise on the fact that you +have a very thin boundary layer in which + + align:start position:0% +have a very thin boundary layer in which + + + align:start position:0% +have a very thin boundary layer in which +the electrochemical you know in which + + align:start position:0% +the electrochemical you know in which + + + align:start position:0% +the electrochemical you know in which +the reagents are confined and if that + + align:start position:0% +the reagents are confined and if that + + + align:start position:0% +the reagents are confined and if that +boundary layer gets too thick and + + align:start position:0% +boundary layer gets too thick and + + + align:start position:0% +boundary layer gets too thick and +reaches the other electrode it screws up + + align:start position:0% +reaches the other electrode it screws up + + + align:start position:0% +reaches the other electrode it screws up +the reaction and doesn't work as a + + align:start position:0% +the reaction and doesn't work as a + + + align:start position:0% +the reaction and doesn't work as a +battery anymore okay so being able to + + align:start position:0% +battery anymore okay so being able to + + + align:start position:0% +battery anymore okay so being able to +resolve right concentration gradients in + + align:start position:0% +resolve right concentration gradients in + + + align:start position:0% +resolve right concentration gradients in +this small domain so it's just important + + align:start position:0% +this small domain so it's just important + + + align:start position:0% +this small domain so it's just important +for this drug problems important in + + align:start position:0% +for this drug problems important in + + + align:start position:0% +for this drug problems important in +general common sort of transport + + align:start position:0% +general common sort of transport + + + align:start position:0% +general common sort of transport +transport a type problem and the + + align:start position:0% +transport a type problem and the + + + align:start position:0% +transport a type problem and the +numerical solution is really going to + + align:start position:0% +numerical solution is really going to + + + align:start position:0% +numerical solution is really going to +hinge on your ability to recognize the + + align:start position:0% +hinge on your ability to recognize the + + + align:start position:0% +hinge on your ability to recognize the +physics and resolve the solution over + + align:start position:0% +physics and resolve the solution over + + + align:start position:0% +physics and resolve the solution over +the length scales that are important in + + align:start position:0% +the length scales that are important in + + + align:start position:0% +the length scales that are important in +the problem okay so that's the number + + align:start position:0% +the problem okay so that's the number + + + align:start position:0% +the problem okay so that's the number +one most important thing for doing these + + align:start position:0% +one most important thing for doing these + + + align:start position:0% +one most important thing for doing these +PDS the rest of the notes okay well take + + align:start position:0% +PDS the rest of the notes okay well take + + + align:start position:0% +PDS the rest of the notes okay well take +take you through the construction of a + + align:start position:0% +take you through the construction of a + + + align:start position:0% +take you through the construction of a +numerical solution to the diffusion + + align:start position:0% +numerical solution to the diffusion + + + align:start position:0% +numerical solution to the diffusion +equation in 2d okay and some different + + align:start position:0% +equation in 2d okay and some different + + + align:start position:0% +equation in 2d okay and some different +scenarios that you might try to employ + + align:start position:0% +scenarios that you might try to employ + + + align:start position:0% +scenarios that you might try to employ +in MATLAB to solve them and how you can + + align:start position:0% +in MATLAB to solve them and how you can + + + align:start position:0% +in MATLAB to solve them and how you can +accelerate the solution using different + + align:start position:0% +accelerate the solution using different + + + align:start position:0% +accelerate the solution using different +MATLAB functions it's fun to try out and + + align:start position:0% +MATLAB functions it's fun to try out and + + + align:start position:0% +MATLAB functions it's fun to try out and +play with you'll see that I can I can + + align:start position:0% +play with you'll see that I can I can + + + align:start position:0% +play with you'll see that I can I can +make the solution to this problem go + + align:start position:0% +make the solution to this problem go + + + align:start position:0% +make the solution to this problem go +very fast for a domain that's quite + + align:start position:0% +very fast for a domain that's quite + + + align:start position:0% +very fast for a domain that's quite +highly discretized by recognizing + + align:start position:0% +highly discretized by recognizing + + + align:start position:0% +highly discretized by recognizing +certain forms of the equations choosing + + align:start position:0% +certain forms of the equations choosing + + + align:start position:0% +certain forms of the equations choosing +certain solvers to solve with okay good + + align:start position:0% +certain solvers to solve with okay good + + + align:start position:0% +certain solvers to solve with okay good +all right I'll meet you guys I'm back + + align:start position:0% +all right I'll meet you guys I'm back + + + align:start position:0% +all right I'll meet you guys I'm back +and we'll hand out these gift cards and + + align:start position:0% +and we'll hand out these gift cards and + + + align:start position:0% +and we'll hand out these gift cards and +good luck on your quiz + + align:start position:0% + + + + align:start position:0% + +you \ No newline at end of file diff --git a/ufM3HLTZ47k.txt b/ufM3HLTZ47k.txt new file mode 100644 index 0000000000000000000000000000000000000000..abd5b3ac1c4d8a2e9be1861dbdacf15a31fbd270 --- /dev/null +++ b/ufM3HLTZ47k.txt @@ -0,0 +1,11979 @@ +align:start position:0% + +The following content is provided under + + align:start position:0% +The following content is provided under + + + align:start position:0% +The following content is provided under +a Creative Common License. Your support + + align:start position:0% +a Creative Common License. Your support + + + align:start position:0% +a Creative Common License. Your support +will help MIT Open Courseware continue + + align:start position:0% +will help MIT Open Courseware continue + + + align:start position:0% +will help MIT Open Courseware continue +to offer high-quality educational + + align:start position:0% +to offer high-quality educational + + + align:start position:0% +to offer high-quality educational +resources for free. To make a donation + + align:start position:0% +resources for free. To make a donation + + + align:start position:0% +resources for free. To make a donation +or view additional materials from + + align:start position:0% +or view additional materials from + + + align:start position:0% +or view additional materials from +hundreds of MIT courses, visit MIT Open + + align:start position:0% +hundreds of MIT courses, visit MIT Open + + + align:start position:0% +hundreds of MIT courses, visit MIT Open +Courseware at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu. Okay, welcome back. Well, + + align:start position:0% +ocw.mit.edu. Okay, welcome back. Well, + + + align:start position:0% +ocw.mit.edu. Okay, welcome back. Well, +sorry, I wasn't here on It's more + + align:start position:0% +sorry, I wasn't here on It's more + + + align:start position:0% +sorry, I wasn't here on It's more +dramatic for me, I guess, than if I had + + align:start position:0% +dramatic for me, I guess, than if I had + + + align:start position:0% +dramatic for me, I guess, than if I had +been here on Tuesday. I hope John did a + + align:start position:0% +been here on Tuesday. I hope John did a + + + align:start position:0% +been here on Tuesday. I hope John did a +did a good job uh covering for me. I'm + + align:start position:0% +did a good job uh covering for me. I'm + + + align:start position:0% +did a good job uh covering for me. I'm +sure he I'm sure he did. So, + + align:start position:0% + + + + align:start position:0% + +um you learned about walking robots. + + align:start position:0% +um you learned about walking robots. + + + align:start position:0% +um you learned about walking robots. +You've learned about lots of robots. You + + align:start position:0% +You've learned about lots of robots. You + + + align:start position:0% +You've learned about lots of robots. You +learned with a handful of very powerful + + align:start position:0% +learned with a handful of very powerful + + + align:start position:0% +learned with a handful of very powerful +uh techniques, I think, for designing + + align:start position:0% +uh techniques, I think, for designing + + + align:start position:0% +uh techniques, I think, for designing +motions for these robots. Um some of my + + align:start position:0% +motions for these robots. Um some of my + + + align:start position:0% +motions for these robots. Um some of my +favorite these days are things like the + + align:start position:0% +favorite these days are things like the + + + align:start position:0% +favorite these days are things like the +durall type methods. + + align:start position:0% +durall type methods. + + + align:start position:0% +durall type methods. +So let's consider um the problem of + + align:start position:0% +So let's consider um the problem of + + + align:start position:0% +So let's consider um the problem of +taking some robot described by our + + align:start position:0% +taking some robot described by our + + + align:start position:0% +taking some robot described by our +standard some nonlinear dynamics + + align:start position:0% +standard some nonlinear dynamics + + + align:start position:0% +standard some nonlinear dynamics +form and taking that robot from an + + align:start position:0% +form and taking that robot from an + + + align:start position:0% +form and taking that robot from an +initial + + align:start position:0% +initial + + + align:start position:0% +initial +condition + + align:start position:0% +condition + + + align:start position:0% +condition +x0 and getting it to some final + + align:start position:0% +x0 and getting it to some final + + + align:start position:0% +x0 and getting it to some final +condition. I don't even care about the + + align:start position:0% +condition. I don't even care about the + + + align:start position:0% +condition. I don't even care about the +time. Say just getting it to um some + + align:start position:0% +time. Say just getting it to um some + + + align:start position:0% +time. Say just getting it to um some +other state x + + align:start position:0% +other state x + + + align:start position:0% +other state x +goal. So what tools have we already got + + align:start position:0% +goal. So what tools have we already got + + + align:start position:0% +goal. So what tools have we already got +um that could help us drive this system + + align:start position:0% +um that could help us drive this system + + + align:start position:0% +um that could help us drive this system +from some initial condition to some goal + + align:start position:0% + + + + align:start position:0% + +state? The answer is a lot of tools, + + align:start position:0% +state? The answer is a lot of tools, + + + align:start position:0% +state? The answer is a lot of tools, +right? Um, if the systems if the state + + align:start position:0% +right? Um, if the systems if the state + + + align:start position:0% +right? Um, if the systems if the state +space is small enough, you could imagine + + align:start position:0% +space is small enough, you could imagine + + + align:start position:0% +space is small enough, you could imagine +designing an optimal control cost + + align:start position:0% +designing an optimal control cost + + + align:start position:0% +designing an optimal control cost +function that we could do dynamic + + align:start position:0% +function that we could do dynamic + + + align:start position:0% +function that we could do dynamic +programming on that would get us to that + + align:start position:0% +programming on that would get us to that + + + align:start position:0% +programming on that would get us to that +goal if we only rewarded ourselves from + + align:start position:0% +goal if we only rewarded ourselves from + + + align:start position:0% +goal if we only rewarded ourselves from +being away from the goal. Um, we could + + align:start position:0% +being away from the goal. Um, we could + + + align:start position:0% +being away from the goal. Um, we could +do a shooting method, right? Um we can + + align:start position:0% +do a shooting method, right? Um we can + + + align:start position:0% +do a shooting method, right? Um we can +even in if we if we if we're using our + + align:start position:0% +even in if we if we if we're using our + + + align:start position:0% +even in if we if we if we're using our +SQP um our snapped type interface to the + + align:start position:0% +SQP um our snapped type interface to the + + + align:start position:0% +SQP um our snapped type interface to the +shooting methods then we could provide a + + align:start position:0% +shooting methods then we could provide a + + + align:start position:0% +shooting methods then we could provide a +final value constraint + + align:start position:0% +final value constraint + + + align:start position:0% +final value constraint +um which says I want the end point of my + + align:start position:0% +um which says I want the end point of my + + + align:start position:0% +um which says I want the end point of my +trajectory to be exactly at the goal and + + align:start position:0% +trajectory to be exactly at the goal and + + + align:start position:0% +trajectory to be exactly at the goal and +that would that would solve this problem + + align:start position:0% +that would that would solve this problem + + + align:start position:0% +that would that would solve this problem +in some cases. Okay. But both of those + + align:start position:0% +in some cases. Okay. But both of those + + + align:start position:0% +in some cases. Okay. But both of those +methods have problems right? The DP + + align:start position:0% +methods have problems right? The DP + + + align:start position:0% +methods have problems right? The DP +doesn't scale. + + align:start position:0% +doesn't scale. + + + align:start position:0% +doesn't scale. +the shooting methods scale + + align:start position:0% +the shooting methods scale + + + align:start position:0% +the shooting methods scale +nicely, but if you ask your shooting + + align:start position:0% +nicely, but if you ask your shooting + + + align:start position:0% +nicely, but if you ask your shooting +method to drive you from X0 to X goal, + + align:start position:0% +method to drive you from X0 to X goal, + + + align:start position:0% +method to drive you from X0 to X goal, +um there's some chance it's going to + + align:start position:0% +um there's some chance it's going to + + + align:start position:0% +um there's some chance it's going to +just say I can't do it, right? I can't + + align:start position:0% +just say I can't do it, right? I can't + + + align:start position:0% +just say I can't do it, right? I can't +satisfy that constraint because it's a + + align:start position:0% +satisfy that constraint because it's a + + + align:start position:0% +satisfy that constraint because it's a +based on a local gradient + + align:start position:0% +based on a local gradient + + + align:start position:0% +based on a local gradient +optimization. And if there's local + + align:start position:0% +optimization. And if there's local + + + align:start position:0% +optimization. And if there's local +minima, + + align:start position:0% +minima, + + + align:start position:0% +minima, +um, snap will just say, I can't satisfy + + align:start position:0% +um, snap will just say, I can't satisfy + + + align:start position:0% +um, snap will just say, I can't satisfy +the constraint, um, x at time final + + align:start position:0% +the constraint, um, x at time final + + + align:start position:0% +the constraint, um, x at time final +equals x goal. Happens a lot. If you're + + align:start position:0% +equals x goal. Happens a lot. If you're + + + align:start position:0% +equals x goal. Happens a lot. If you're +looking at hard enough, interesting + + align:start position:0% +looking at hard enough, interesting + + + align:start position:0% +looking at hard enough, interesting +enough problems, it'll happen to you. + + align:start position:0% +enough problems, it'll happen to you. + + + align:start position:0% +enough problems, it'll happen to you. +Okay. So, what do you do? Do you just + + align:start position:0% +Okay. So, what do you do? Do you just + + + align:start position:0% +Okay. So, what do you do? Do you just +say, you know, find a new research + + align:start position:0% +say, you know, find a new research + + + align:start position:0% +say, you know, find a new research +problem, tell my adviser, I got to find + + align:start position:0% +problem, tell my adviser, I got to find + + + align:start position:0% +problem, tell my adviser, I got to find +something else. Okay. There's more + + align:start position:0% +something else. Okay. There's more + + + align:start position:0% +something else. Okay. There's more +things you can try, right? Um + + align:start position:0% +things you can try, right? Um + + + align:start position:0% +things you can try, right? Um +the methods I want to talk about + + align:start position:0% +the methods I want to talk about + + + align:start position:0% +the methods I want to talk about +today are the feasible motion planning + + align:start position:0% +today are the feasible motion planning + + + align:start position:0% +today are the feasible motion planning +algorithms. Okay. So motion planning is + + align:start position:0% +algorithms. Okay. So motion planning is + + + align:start position:0% +algorithms. Okay. So motion planning is +a is a very broad term. It's used all + + align:start position:0% +a is a very broad term. It's used all + + + align:start position:0% +a is a very broad term. It's used all +the time in + + align:start position:0% +the time in + + + align:start position:0% +the time in +robotics. I'd say roughly everything + + align:start position:0% +robotics. I'd say roughly everything + + + align:start position:0% +robotics. I'd say roughly everything +we've done to date has been a motion + + align:start position:0% +we've done to date has been a motion + + + align:start position:0% +we've done to date has been a motion +planning algorithm. It's like saying + + align:start position:0% +planning algorithm. It's like saying + + + align:start position:0% +planning algorithm. It's like saying +it's a control algorithm. It's a very + + align:start position:0% +it's a control algorithm. It's a very + + + align:start position:0% +it's a control algorithm. It's a very +general term. Some people um debate when + + align:start position:0% +general term. Some people um debate when + + + align:start position:0% +general term. Some people um debate when +something you know whether whether an + + align:start position:0% +something you know whether whether an + + + align:start position:0% +something you know whether whether an +algorithm is a motion planning algorithm + + align:start position:0% +algorithm is a motion planning algorithm + + + align:start position:0% +algorithm is a motion planning algorithm +or an optimal control algorithm or + + align:start position:0% +or an optimal control algorithm or + + + align:start position:0% +or an optimal control algorithm or +whatever. I think that's sort of a waste + + align:start position:0% +whatever. I think that's sort of a waste + + + align:start position:0% +whatever. I think that's sort of a waste +of time. I would say they're all motion + + align:start position:0% +of time. I would say they're all motion + + + align:start position:0% +of time. I would say they're all motion +planning algorithms. Most of the things + + align:start position:0% +planning algorithms. Most of the things + + + align:start position:0% +planning algorithms. Most of the things +we've talked about so + + align:start position:0% +we've talked about so + + + align:start position:0% +we've talked about so +far I would call optimal motion + + align:start position:0% + + + + align:start position:0% + +planning, right? where we actually had a + + align:start position:0% +planning, right? where we actually had a + + + align:start position:0% +planning, right? where we actually had a +cost function flying around to do + + align:start position:0% + + + + align:start position:0% + +it. Often times motion plans go from a + + align:start position:0% +it. Often times motion plans go from a + + + align:start position:0% +it. Often times motion plans go from a +start to a goal. Oftent times they're + + align:start position:0% +start to a goal. Oftent times they're + + + align:start position:0% +start to a goal. Oftent times they're +open loop but that's not really + + align:start position:0% +open loop but that's not really + + + align:start position:0% +open loop but that's not really +defining. You can do feedback motion + + align:start position:0% +defining. You can do feedback motion + + + align:start position:0% +defining. You can do feedback motion +planning and motion planning is just a + + align:start position:0% +planning and motion planning is just a + + + align:start position:0% +planning and motion planning is just a +very general term saying I'm designing + + align:start position:0% +very general term saying I'm designing + + + align:start position:0% +very general term saying I'm designing +the the motions of my machine. + + align:start position:0% +the the motions of my machine. + + + align:start position:0% +the the motions of my machine. +The reason I want to use motion planning + + align:start position:0% +The reason I want to use motion planning + + + align:start position:0% +The reason I want to use motion planning +in the title for this lecture and next + + align:start position:0% +in the title for this lecture and next + + + align:start position:0% +in the title for this lecture and next +lecture um is because there's another + + align:start position:0% +lecture um is because there's another + + + align:start position:0% +lecture um is because there's another +set of motion there's an important class + + align:start position:0% +set of motion there's an important class + + + align:start position:0% +set of motion there's an important class +of motion planning algorithms that are + + align:start position:0% +of motion planning algorithms that are + + + align:start position:0% +of motion planning algorithms that are +not covered by the optimal control + + align:start position:0% +not covered by the optimal control + + + align:start position:0% +not covered by the optimal control +algorithms and that's these feasible + + align:start position:0% +algorithms and that's these feasible + + + align:start position:0% +algorithms and that's these feasible +motion planning you + + align:start position:0% + + + + align:start position:0% + +know + + align:start position:0% +know + + + align:start position:0% +know +algorithms. So the optimal motion + + align:start position:0% +algorithms. So the optimal motion + + + align:start position:0% +algorithms. So the optimal motion +planning algorithms try to get me from + + align:start position:0% +planning algorithms try to get me from + + + align:start position:0% +planning algorithms try to get me from +X0 to X goal in some way that's good by + + align:start position:0% +X0 to X goal in some way that's good by + + + align:start position:0% +X0 to X goal in some way that's good by +some ascored by some cost + + align:start position:0% +some ascored by some cost + + + align:start position:0% +some ascored by some cost +function. Feasible motion planning + + align:start position:0% +function. Feasible motion planning + + + align:start position:0% +function. Feasible motion planning +algorithms aspire to do less right they + + align:start position:0% +algorithms aspire to do less right they + + + align:start position:0% +algorithms aspire to do less right they +I just say I'll get me any state any + + align:start position:0% +I just say I'll get me any state any + + + align:start position:0% +I just say I'll get me any state any +trajectory that gets me from the start + + align:start position:0% +trajectory that gets me from the start + + + align:start position:0% +trajectory that gets me from the start +to the goal. Okay because they sacrifice + + align:start position:0% +to the goal. Okay because they sacrifice + + + align:start position:0% +to the goal. Okay because they sacrifice +their claims on optimality oftentimes + + align:start position:0% +their claims on optimality oftentimes + + + align:start position:0% +their claims on optimality oftentimes +these algorithms will work for more + + align:start position:0% +these algorithms will work for more + + + align:start position:0% +these algorithms will work for more +complicated systems. + + align:start position:0% +complicated systems. + + + align:start position:0% +complicated systems. +Okay. So the the the message I want to + + align:start position:0% +Okay. So the the the message I want to + + + align:start position:0% +Okay. So the the the message I want to +sort of deliver today is that there are + + align:start position:0% +sort of deliver today is that there are + + + align:start position:0% +sort of deliver today is that there are +a lot of good feasible motion planning + + align:start position:0% +a lot of good feasible motion planning + + + align:start position:0% +a lot of good feasible motion planning +algorithms out there in the world. We'll + + align:start position:0% +algorithms out there in the world. We'll + + + align:start position:0% +algorithms out there in the world. We'll +we'll talk about a some of the most + + align:start position:0% +we'll talk about a some of the most + + + align:start position:0% +we'll talk about a some of the most +exciting ones I think. And actually even + + align:start position:0% +exciting ones I think. And actually even + + + align:start position:0% +exciting ones I think. And actually even +if you care about optimality, even if + + align:start position:0% +if you care about optimality, even if + + + align:start position:0% +if you care about optimality, even if +deep down in your core you say this is a + + align:start position:0% +deep down in your core you say this is a + + + align:start position:0% +deep down in your core you say this is a +cost function that I must + + align:start position:0% +cost function that I must + + + align:start position:0% +cost function that I must +optimize for my life to be + + align:start position:0% +optimize for my life to be + + + align:start position:0% +optimize for my life to be +complete, you still should care about + + align:start position:0% +complete, you still should care about + + + align:start position:0% +complete, you still should care about +feasible motion planning algorithms. + + align:start position:0% +feasible motion planning algorithms. + + + align:start position:0% +feasible motion planning algorithms. +because they can do something like + + align:start position:0% +because they can do something like + + + align:start position:0% +because they can do something like +seed a durall method, let's say, uh, and + + align:start position:0% +seed a durall method, let's say, uh, and + + + align:start position:0% +seed a durall method, let's say, uh, and +get it out of local minima. So, let's + + align:start position:0% +get it out of local minima. So, let's + + + align:start position:0% +get it out of local minima. So, let's +say I have an Acrobot that I'm trying to + + align:start position:0% +say I have an Acrobot that I'm trying to + + + align:start position:0% +say I have an Acrobot that I'm trying to +swing up and I've got a a table right + + align:start position:0% +swing up and I've got a a table right + + + align:start position:0% +swing up and I've got a a table right +here, so I can't swing that way. And + + align:start position:0% +here, so I can't swing that way. And + + + align:start position:0% +here, so I can't swing that way. And +whatever my my initial um my initial + + align:start position:0% +whatever my my initial um my initial + + + align:start position:0% +whatever my my initial um my initial +guess at the trajectory, the system + + align:start position:0% +guess at the trajectory, the system + + + align:start position:0% +guess at the trajectory, the system +keeps banging up against this. It can't + + align:start position:0% +keeps banging up against this. It can't + + + align:start position:0% +keeps banging up against this. It can't +figure out a way to to turn around and + + align:start position:0% +figure out a way to to turn around and + + + align:start position:0% +figure out a way to to turn around and +go back the opposite way to get to the + + align:start position:0% +go back the opposite way to get to the + + + align:start position:0% +go back the opposite way to get to the +top, right? Or maybe there's a, you + + align:start position:0% +top, right? Or maybe there's a, you + + + align:start position:0% +top, right? Or maybe there's a, you +know, a table that you have to go + + align:start position:0% +know, a table that you have to go + + + align:start position:0% +know, a table that you have to go +through it just in a certain way, + + align:start position:0% +through it just in a certain way, + + + align:start position:0% +through it just in a certain way, +right? I would say if your if + + align:start position:0% +right? I would say if your if + + + align:start position:0% +right? I would say if your if +your shooting method is having a trouble + + align:start position:0% +your shooting method is having a trouble + + + align:start position:0% +your shooting method is having a trouble +finding its way to the goal, maybe you + + align:start position:0% +finding its way to the goal, maybe you + + + align:start position:0% +finding its way to the goal, maybe you +should back off on optimality. Just find + + align:start position:0% +should back off on optimality. Just find + + + align:start position:0% +should back off on optimality. Just find +any old trajectory that gets to the goal + + align:start position:0% +any old trajectory that gets to the goal + + + align:start position:0% +any old trajectory that gets to the goal +and then take that result of that motion + + align:start position:0% +and then take that result of that motion + + + align:start position:0% +and then take that result of that motion +planning algorithm, hand it to Durall, + + align:start position:0% +planning algorithm, hand it to Durall, + + + align:start position:0% +planning algorithm, hand it to Durall, +and let it then do the rest of the + + align:start position:0% +and let it then do the rest of the + + + align:start position:0% +and let it then do the rest of the +optimization. Okay, we'll we'll say more + + align:start position:0% +optimization. Okay, we'll we'll say more + + + align:start position:0% +optimization. Okay, we'll we'll say more +about this. I just wanted to to give you + + align:start position:0% +about this. I just wanted to to give you + + + align:start position:0% +about this. I just wanted to to give you +some context about why we want to talk + + align:start position:0% +some context about why we want to talk + + + align:start position:0% +some context about why we want to talk +about this extra set of + + align:start position:0% +about this extra set of + + + align:start position:0% +about this extra set of +algorithms. In general, we're going to + + align:start position:0% +algorithms. In general, we're going to + + + align:start position:0% +algorithms. In general, we're going to +expect these um these to scale to + + align:start position:0% +expect these um these to scale to + + + align:start position:0% +expect these um these to scale to +slightly higher dimensional systems than + + align:start position:0% +slightly higher dimensional systems than + + + align:start position:0% +slightly higher dimensional systems than +the optimal control algorithms we've + + align:start position:0% +the optimal control algorithms we've + + + align:start position:0% +the optimal control algorithms we've +talked about so far and to be more + + align:start position:0% +talked about so far and to be more + + + align:start position:0% +talked about so far and to be more +global than uh than the shooting + + align:start position:0% +global than uh than the shooting + + + align:start position:0% +global than uh than the shooting +methods. + + align:start position:0% + + + + align:start position:0% + +There's a great book on all of this + + align:start position:0% +There's a great book on all of this + + + align:start position:0% +There's a great book on all of this +stuff. + + align:start position:0% +stuff. + + + align:start position:0% +stuff. +Um called uh I guess it should be + + align:start position:0% +Um called uh I guess it should be + + + align:start position:0% +Um called uh I guess it should be +underlined, planning + + align:start position:0% + + + + align:start position:0% + +algorithms. So I pro I just spelled + + align:start position:0% +algorithms. So I pro I just spelled + + + align:start position:0% +algorithms. So I pro I just spelled +planning wrong, right? So I'm I'm + + align:start position:0% +planning wrong, right? So I'm I'm + + + align:start position:0% +planning wrong, right? So I'm I'm +completely sleepd deprived. If I do + + align:start position:0% +completely sleepd deprived. If I do + + + align:start position:0% +completely sleepd deprived. If I do +stupid things like that, uh call them + + align:start position:0% +stupid things like that, uh call them + + + align:start position:0% +stupid things like that, uh call them +out. I'll fix them. + + align:start position:0% + + + + align:start position:0% + +something about kid number two, the the + + align:start position:0% +something about kid number two, the the + + + align:start position:0% +something about kid number two, the the +first kid stays awake while the other + + align:start position:0% +first kid stays awake while the other + + + align:start position:0% +first kid stays awake while the other +kid sleeps and vice versa. It just makes + + align:start position:0% +kid sleeps and vice versa. It just makes + + + align:start position:0% +kid sleeps and vice versa. It just makes +it that much more interesting. + + align:start position:0% +it that much more interesting. + + + align:start position:0% +it that much more interesting. +Yeah. And planning algorithms, the book + + align:start position:0% +Yeah. And planning algorithms, the book + + + align:start position:0% +Yeah. And planning algorithms, the book +by Steve Lavel is actually Steve's got + + align:start position:0% +by Steve Lavel is actually Steve's got + + + align:start position:0% +by Steve Lavel is actually Steve's got +it on his website, the full version. uh + + align:start position:0% +it on his website, the full version. uh + + + align:start position:0% +it on his website, the full version. uh +you can download for free. So it's nice + + align:start position:0% +you can download for free. So it's nice + + + align:start position:0% +you can download for free. So it's nice +accessible text that you can check out + + align:start position:0% +accessible text that you can check out + + + align:start position:0% +accessible text that you can check out +if if you like + + align:start position:0% +if if you like + + + align:start position:0% +if if you like +it. Okay. So before we get into our + + align:start position:0% +it. Okay. So before we get into our + + + align:start position:0% +it. Okay. So before we get into our +first feasible motion planning + + align:start position:0% +first feasible motion planning + + + align:start position:0% +first feasible motion planning +algorithm, let me give you just a little + + align:start position:0% +algorithm, let me give you just a little + + + align:start position:0% +algorithm, let me give you just a little +sort of + + align:start position:0% +sort of + + + align:start position:0% +sort of +culture. The motion planning algorithms + + align:start position:0% +culture. The motion planning algorithms + + + align:start position:0% +culture. The motion planning algorithms +I think um actually grew up not so much + + align:start position:0% +I think um actually grew up not so much + + + align:start position:0% +I think um actually grew up not so much +in the controls community but in the + + align:start position:0% +in the controls community but in the + + + align:start position:0% +in the controls community but in the +more the artificial intelligence + + align:start position:0% +more the artificial intelligence + + + align:start position:0% +more the artificial intelligence +community, right? Um and there's a + + align:start position:0% +community, right? Um and there's a + + + align:start position:0% +community, right? Um and there's a +reason for that. Um there are serious + + align:start position:0% +reason for that. Um there are serious + + + align:start position:0% +reason for that. Um there are serious +people out there that think the only + + align:start position:0% +people out there that think the only + + + align:start position:0% +people out there that think the only +thing there is to + + align:start position:0% +thing there is to + + + align:start position:0% +thing there is to +intelligence is the ability to do + + align:start position:0% +intelligence is the ability to do + + + align:start position:0% +intelligence is the ability to do +search. Okay. So I I I think that + + align:start position:0% +search. Okay. So I I I think that + + + align:start position:0% +search. Okay. So I I I think that +uh artificial intelligence via + + align:start position:0% +uh artificial intelligence via + + + align:start position:0% +uh artificial intelligence via +search to some extent sounds + + align:start position:0% +search to some extent sounds + + + align:start position:0% +search to some extent sounds +ridiculous but it's pretty hard to + + align:start position:0% +ridiculous but it's pretty hard to + + + align:start position:0% +ridiculous but it's pretty hard to +disprove and some people really think + + align:start position:0% +disprove and some people really think + + + align:start position:0% +disprove and some people really think +that that's that's uh that's the way it + + align:start position:0% +that that's that's uh that's the way it + + + align:start position:0% +that that's that's uh that's the way it +happens. So let me give you some some + + align:start position:0% +happens. So let me give you some some + + + align:start position:0% +happens. So let me give you some some +cultural examples of where that came + + align:start position:0% +cultural examples of where that came + + + align:start position:0% +cultural examples of where that came +from. Right? The the original some of + + align:start position:0% +from. Right? The the original some of + + + align:start position:0% +from. Right? The the original some of +the original um efforts in artificial + + align:start position:0% +the original um efforts in artificial + + + align:start position:0% +the original um efforts in artificial +intelligence. They thought um I can my + + align:start position:0% +intelligence. They thought um I can my + + + align:start position:0% +intelligence. They thought um I can my +computer program will be intelligent if + + align:start position:0% +computer program will be intelligent if + + + align:start position:0% +computer program will be intelligent if +it can play a game like checkers or + + align:start position:0% +it can play a game like checkers or + + + align:start position:0% +it can play a game like checkers or +chess, right? And as early as like the + + align:start position:0% +chess, right? And as early as like the + + + align:start position:0% +chess, right? And as early as like the +50s, Art Samuels building checker + + align:start position:0% +50s, Art Samuels building checker + + + align:start position:0% +50s, Art Samuels building checker +playing robots that are basically doing + + align:start position:0% +playing robots that are basically doing + + + align:start position:0% +playing robots that are basically doing +search in order to try to figure out how + + align:start position:0% +search in order to try to figure out how + + + align:start position:0% +search in order to try to figure out how +to to beat their opponent in in chess, + + align:start position:0% +to to beat their opponent in in chess, + + + align:start position:0% +to to beat their opponent in in chess, +right? So or in checkers, sorry. + + align:start position:0% + + + + align:start position:0% + +Um like checkers there's Samuel in the + + align:start position:0% +Um like checkers there's Samuel in the + + + align:start position:0% +Um like checkers there's Samuel in the +50s. + + align:start position:0% + + + + align:start position:0% + +um chess we can leap forward to uh IBM's + + align:start position:0% +um chess we can leap forward to uh IBM's + + + align:start position:0% +um chess we can leap forward to uh IBM's +deep blue let's say uh in the last + + align:start position:0% +deep blue let's say uh in the last + + + align:start position:0% +deep blue let's say uh in the last +decade right + + align:start position:0% +decade right + + + align:start position:0% +decade right +um these are computer programs that at + + align:start position:0% +um these are computer programs that at + + + align:start position:0% +um these are computer programs that at +times can play with the sophistication + + align:start position:0% +times can play with the sophistication + + + align:start position:0% +times can play with the sophistication +of a trained human right and they're + + align:start position:0% +of a trained human right and they're + + + align:start position:0% +of a trained human right and they're +based on simply having the rules of the + + align:start position:0% +based on simply having the rules of the + + + align:start position:0% +based on simply having the rules of the +game + + align:start position:0% +game + + + align:start position:0% +game +programmed some databases of of moves + + align:start position:0% +programmed some databases of of moves + + + align:start position:0% +programmed some databases of of moves +that they've stored up a lot of them in + + align:start position:0% +that they've stored up a lot of them in + + + align:start position:0% +that they've stored up a lot of them in +the deep blue + + align:start position:0% +the deep blue + + + align:start position:0% +the deep blue +and search, right? Finding um the way to + + align:start position:0% +and search, right? Finding um the way to + + + align:start position:0% +and search, right? Finding um the way to +move my robot from X0 to X goal, you can + + align:start position:0% +move my robot from X0 to X goal, you can + + + align:start position:0% +move my robot from X0 to X goal, you can +imagine being very very analogous to + + align:start position:0% +imagine being very very analogous to + + + align:start position:0% +imagine being very very analogous to +finding my uh take my taking my computer + + align:start position:0% +finding my uh take my taking my computer + + + align:start position:0% +finding my uh take my taking my computer +game and finding from an initial board + + align:start position:0% +game and finding from an initial board + + + align:start position:0% +game and finding from an initial board +configuration to a a winning board + + align:start position:0% +configuration to a a winning board + + + align:start position:0% +configuration to a a winning board +configuration. They're exactly the same + + align:start position:0% +configuration. They're exactly the same + + + align:start position:0% +configuration. They're exactly the same +problem. Okay. So because of things like + + align:start position:0% +problem. Okay. So because of things like + + + align:start position:0% +problem. Okay. So because of things like +computer games, the artificial + + align:start position:0% +computer games, the artificial + + + align:start position:0% +computer games, the artificial +intelligence community really started + + align:start position:0% +intelligence community really started + + + align:start position:0% +intelligence community really started +building up these these search + + align:start position:0% +building up these these search + + + align:start position:0% +building up these these search +algorithms and and they were very + + align:start position:0% +algorithms and and they were very + + + align:start position:0% +algorithms and and they were very +fundamental. The other + + align:start position:0% +fundamental. The other + + + align:start position:0% +fundamental. The other +um + + align:start position:0% +um + + + align:start position:0% +um +um the other big uh push I think from + + align:start position:0% +um the other big uh push I think from + + + align:start position:0% +um the other big uh push I think from +the AI community was in ideas like + + align:start position:0% +the AI community was in ideas like + + + align:start position:0% +the AI community was in ideas like +theorem + + align:start position:0% + + + + align:start position:0% + +proving, right? So + + align:start position:0% +proving, right? So + + + align:start position:0% +proving, right? So +a, you know, an AI zealot of of 40 years + + align:start position:0% +a, you know, an AI zealot of of 40 years + + + align:start position:0% +a, you know, an AI zealot of of 40 years +ago might have told you that mathematics + + align:start position:0% +ago might have told you that mathematics + + + align:start position:0% +ago might have told you that mathematics +would be obsolete by now because all you + + align:start position:0% +would be obsolete by now because all you + + + align:start position:0% +would be obsolete by now because all you +have to do is program the basic rules of + + align:start position:0% +have to do is program the basic rules of + + + align:start position:0% +have to do is program the basic rules of +mathematics into a into a a set of rules + + align:start position:0% +mathematics into a into a a set of rules + + + align:start position:0% +mathematics into a into a a set of rules +that your computer program could uh + + align:start position:0% +that your computer program could uh + + + align:start position:0% +that your computer program could uh +could evaluate. and then proving where + + align:start position:0% +could evaluate. and then proving where + + + align:start position:0% +could evaluate. and then proving where +whether something was true or not is + + align:start position:0% +whether something was true or not is + + + align:start position:0% +whether something was true or not is +just a matter of finding the right chain + + align:start position:0% +just a matter of finding the right chain + + + align:start position:0% +just a matter of finding the right chain +of of small logical deductions to put + + align:start position:0% +of of small logical deductions to put + + + align:start position:0% +of of small logical deductions to put +together to find to be able to prove + + align:start position:0% +together to find to be able to prove + + + align:start position:0% +together to find to be able to prove +that P equals NP or something like that, + + align:start position:0% +that P equals NP or something like that, + + + align:start position:0% +that P equals NP or something like that, +right? Okay. Uh and actually, you know, + + align:start position:0% +right? Okay. Uh and actually, you know, + + + align:start position:0% +right? Okay. Uh and actually, you know, +I I joke, but that's actually a very + + align:start position:0% +I I joke, but that's actually a very + + + align:start position:0% +I I joke, but that's actually a very +powerful thing that works today, right? + + align:start position:0% +powerful thing that works today, right? + + + align:start position:0% +powerful thing that works today, right? +If you've used Mathematica or Maple and + + align:start position:0% +If you've used Mathematica or Maple and + + + align:start position:0% +If you've used Mathematica or Maple and +you've asked it to simplify, right? + + align:start position:0% +you've asked it to simplify, right? + + + align:start position:0% +you've asked it to simplify, right? +That's a result of of theorem proving + + align:start position:0% +That's a result of of theorem proving + + + align:start position:0% +That's a result of of theorem proving +work that people did in artificial + + align:start position:0% +work that people did in artificial + + + align:start position:0% +work that people did in artificial +intelligence a long time ago, right? And + + align:start position:0% +intelligence a long time ago, right? And + + + align:start position:0% +intelligence a long time ago, right? And +again, it's a matter of designing the + + align:start position:0% +again, it's a matter of designing the + + + align:start position:0% +again, it's a matter of designing the +rules of the game, which is a collection + + align:start position:0% +rules of the game, which is a collection + + + align:start position:0% +rules of the game, which is a collection +in that case of mathematical primitives + + align:start position:0% +in that case of mathematical primitives + + + align:start position:0% +in that case of mathematical primitives +and finding a a path from from your + + align:start position:0% +and finding a a path from from your + + + align:start position:0% +and finding a a path from from your +initial uh knowledge to some proof, + + align:start position:0% +initial uh knowledge to some proof, + + + align:start position:0% +initial uh knowledge to some proof, +let's say. + + align:start position:0% + + + + align:start position:0% + +But even going beyond that, there's + + align:start position:0% +But even going beyond that, there's + + + align:start position:0% +But even going beyond that, there's +people out there that um my favorite my + + align:start position:0% +people out there that um my favorite my + + + align:start position:0% +people out there that um my favorite my +favorite instance of this is there's a + + align:start position:0% +favorite instance of this is there's a + + + align:start position:0% +favorite instance of this is there's a +guy um David Lynette who's um somewhere + + align:start position:0% +guy um David Lynette who's um somewhere + + + align:start position:0% +guy um David Lynette who's um somewhere +in Texas right now typing well he's got + + align:start position:0% +in Texas right now typing well he's got + + + align:start position:0% +in Texas right now typing well he's got +teams of people typing random factoids + + align:start position:0% +teams of people typing random factoids + + + align:start position:0% +teams of people typing random factoids +into computers um he's got this project + + align:start position:0% +into computers um he's got this project + + + align:start position:0% +into computers um he's got this project +called uh + + align:start position:0% +called uh + + + align:start position:0% +called uh +sick. How many people have heard of sik? + + align:start position:0% +sick. How many people have heard of sik? + + + align:start position:0% +sick. How many people have heard of sik? +Yeah. + + align:start position:0% +Yeah. + + + align:start position:0% +Yeah. +So, I think this guy believes that um if + + align:start position:0% +So, I think this guy believes that um if + + + align:start position:0% +So, I think this guy believes that um if +I can get enough people to type in + + align:start position:0% +I can get enough people to type in + + + align:start position:0% +I can get enough people to type in +things like dogs chase cats and you know + + align:start position:0% +things like dogs chase cats and you know + + + align:start position:0% +things like dogs chase cats and you know +balloons go up or something, I don't + + align:start position:0% +balloons go up or something, I don't + + + align:start position:0% +balloons go up or something, I don't +know, enough random factoids into this + + align:start position:0% +know, enough random factoids into this + + + align:start position:0% +know, enough random factoids into this +computer and he builds up an ontology of + + align:start position:0% + + + + align:start position:0% + +knowledge, just some big collection of + + align:start position:0% +knowledge, just some big collection of + + + align:start position:0% +knowledge, just some big collection of +facts that and a good search algorithm + + align:start position:0% +facts that and a good search algorithm + + + align:start position:0% +facts that and a good search algorithm +to back it + + align:start position:0% +to back it + + + align:start position:0% +to back it +that his computer will will achieve + + align:start position:0% +that his computer will will achieve + + + align:start position:0% +that his computer will will achieve +intelligence. You'll be able to answer + + align:start position:0% +intelligence. You'll be able to answer + + + align:start position:0% +intelligence. You'll be able to answer +any query, be completely + + align:start position:0% +any query, be completely + + + align:start position:0% +any query, be completely +indistinguishable from a human. You + + align:start position:0% +indistinguishable from a human. You + + + align:start position:0% +indistinguishable from a human. You +could ask it any query and as long as + + align:start position:0% +could ask it any query and as long as + + + align:start position:0% +could ask it any query and as long as +it's got the right chain of factoids + + align:start position:0% +it's got the right chain of factoids + + + align:start position:0% +it's got the right chain of factoids +stored away and a good search algorithm + + align:start position:0% +stored away and a good search algorithm + + + align:start position:0% +stored away and a good search algorithm +behind it, then this thing is + + align:start position:0% +behind it, then this thing is + + + align:start position:0% +behind it, then this thing is +intelligent. Mhm. And it's been, you + + align:start position:0% +intelligent. Mhm. And it's been, you + + + align:start position:0% +intelligent. Mhm. And it's been, you +know, people have been typing things in + + align:start position:0% +know, people have been typing things in + + + align:start position:0% +know, people have been typing things in +for a really long time. And you can + + align:start position:0% +for a really long time. And you can + + + align:start position:0% +for a really long time. And you can +actually, you know, you can go and you + + align:start position:0% +actually, you know, you can go and you + + + align:start position:0% +actually, you know, you can go and you +can get the student version or whatever + + align:start position:0% +can get the student version or whatever + + + align:start position:0% +can get the student version or whatever +and and ask it questions and you can get + + align:start position:0% +and and ask it questions and you can get + + + align:start position:0% +and and ask it questions and you can get +the research version and and ask it + + align:start position:0% +the research version and and ask it + + + align:start position:0% +the research version and and ask it +questions and people use it. And + + align:start position:0% +questions and people use it. And + + + align:start position:0% +questions and people use it. And +um I mean Google I think works better + + align:start position:0% +um I mean Google I think works better + + + align:start position:0% +um I mean Google I think works better +because it's accessing word net which is + + align:start position:0% +because it's accessing word net which is + + + align:start position:0% +because it's accessing word net which is +a basically an ontology of of synonyms + + align:start position:0% +a basically an ontology of of synonyms + + + align:start position:0% +a basically an ontology of of synonyms +and things like this. These sound + + align:start position:0% +and things like this. These sound + + + align:start position:0% +and things like this. These sound +crazy. Um but they're the backbone of + + align:start position:0% +crazy. Um but they're the backbone of + + + align:start position:0% +crazy. Um but they're the backbone of +some of the things that you use every + + align:start position:0% +some of the things that you use every + + + align:start position:0% +some of the things that you use every +day + + align:start position:0% + + + + align:start position:0% + +right? Okay. So for whatever reason, you + + align:start position:0% +right? Okay. So for whatever reason, you + + + align:start position:0% +right? Okay. So for whatever reason, you +know, for these kind of reasons, the + + align:start position:0% +know, for these kind of reasons, the + + + align:start position:0% +know, for these kind of reasons, the +search algorithms, the motion planning + + align:start position:0% +search algorithms, the motion planning + + + align:start position:0% +search algorithms, the motion planning +algorithms that that we're going to talk + + align:start position:0% +algorithms that that we're going to talk + + + align:start position:0% +algorithms that that we're going to talk +about, which are today used a lot in + + align:start position:0% +about, which are today used a lot in + + + align:start position:0% +about, which are today used a lot in +robotics, grew up under the computer + + align:start position:0% +robotics, grew up under the computer + + + align:start position:0% +robotics, grew up under the computer +science umbrella, under artificial + + align:start position:0% +science umbrella, under artificial + + + align:start position:0% +science umbrella, under artificial +intelligence. Mhm. + + align:start position:0% + + + + align:start position:0% + +So the term motion + + align:start position:0% + + + + align:start position:0% + +planning, you know, typically implies + + align:start position:0% +planning, you know, typically implies + + + align:start position:0% +planning, you know, typically implies +that you've got some dynamical system + + align:start position:0% +that you've got some dynamical system + + + align:start position:0% +that you've got some dynamical system +you're you're shoving around, let's + + align:start position:0% +you're you're shoving around, let's + + + align:start position:0% +you're you're shoving around, let's +say, but it's it's clearly + + align:start position:0% +say, but it's it's clearly + + + align:start position:0% +say, but it's it's clearly +just an instance of this search problem. + + align:start position:0% +just an instance of this search problem. + + + align:start position:0% +just an instance of this search problem. +When people talk about motion planning + + align:start position:0% +When people talk about motion planning + + + align:start position:0% +When people talk about motion planning +in robotics, + + align:start position:0% +in robotics, + + + align:start position:0% +in robotics, +um there are problems that that people + + align:start position:0% +um there are problems that that people + + + align:start position:0% +um there are problems that that people +care about a lot. + + align:start position:0% + + + + align:start position:0% + +Um a majority of the motion planning + + align:start position:0% +Um a majority of the motion planning + + + align:start position:0% +Um a majority of the motion planning +literature in robotics is cons concerned + + align:start position:0% +literature in robotics is cons concerned + + + align:start position:0% +literature in robotics is cons concerned +with kinematic motion planning. + + align:start position:0% + + + + align:start position:0% + +um often with obstacles or something + + align:start position:0% +um often with obstacles or something + + + align:start position:0% +um often with obstacles or something +like this. + + align:start position:0% + + + + align:start position:0% + +So, if I have a a robotic arm with 10 + + align:start position:0% +So, if I have a a robotic arm with 10 + + + align:start position:0% +So, if I have a a robotic arm with 10 +degrees of freedom and I want to reach + + align:start position:0% +degrees of freedom and I want to reach + + + align:start position:0% +degrees of freedom and I want to reach +through some complicated geometry to get + + align:start position:0% +through some complicated geometry to get + + + align:start position:0% +through some complicated geometry to get +uh to turn a a doorork knob or to to + + align:start position:0% +uh to turn a a doorork knob or to to + + + align:start position:0% +uh to turn a a doorork knob or to to +reach down and pick up some apart from + + align:start position:0% +reach down and pick up some apart from + + + align:start position:0% +reach down and pick up some apart from +assembly, then that's a complicated + + align:start position:0% +assembly, then that's a complicated + + + align:start position:0% +assembly, then that's a complicated +geometric problem. + + align:start position:0% +geometric problem. + + + align:start position:0% +geometric problem. +Um, typically you assume that the + + align:start position:0% +Um, typically you assume that the + + + align:start position:0% +Um, typically you assume that the +systems are fully actuated. You don't + + align:start position:0% +systems are fully actuated. You don't + + + align:start position:0% +systems are fully actuated. You don't +worry about actually handling the + + align:start position:0% +worry about actually handling the + + + align:start position:0% +worry about actually handling the +trajectory once you get there. that's + + align:start position:0% +trajectory once you get there. that's + + + align:start position:0% +trajectory once you get there. that's +are normally assumed away and they + + align:start position:0% +are normally assumed away and they + + + align:start position:0% +are normally assumed away and they +assume that all trajectories are + + align:start position:0% +assume that all trajectories are + + + align:start position:0% +assume that all trajectories are +feasible. They're just trying to find + + align:start position:0% +feasible. They're just trying to find + + + align:start position:0% +feasible. They're just trying to find +some um path through the obstacle field. + + align:start position:0% +some um path through the obstacle field. + + + align:start position:0% +some um path through the obstacle field. +Okay. So um one of the key problems that + + align:start position:0% +Okay. So um one of the key problems that + + + align:start position:0% +Okay. So um one of the key problems that +you can sort of think about in in that + + align:start position:0% +you can sort of think about in in that + + + align:start position:0% +you can sort of think about in in that +um + + align:start position:0% + + + + align:start position:0% + +world is a piano movers problem. + + align:start position:0% + + + + align:start position:0% + +How many people know the piano mover's + + align:start position:0% +How many people know the piano mover's + + + align:start position:0% +How many people know the piano mover's +problem? Okay. How many people have ever + + align:start position:0% +problem? Okay. How many people have ever + + + align:start position:0% +problem? Okay. How many people have ever +moved a couch into a dorm room? Okay. + + align:start position:0% +moved a couch into a dorm room? Okay. + + + align:start position:0% +moved a couch into a dorm room? Okay. +You all know the the piano movers + + align:start position:0% +You all know the the piano movers + + + align:start position:0% +You all know the the piano movers +problem then, + + align:start position:0% +problem then, + + + align:start position:0% +problem then, +right? Basic task is you have some 3D + + align:start position:0% +right? Basic task is you have some 3D + + + align:start position:0% +right? Basic task is you have some 3D +shape. You have a bunch of obstacles. + + align:start position:0% +shape. You have a bunch of obstacles. + + + align:start position:0% +shape. You have a bunch of obstacles. +You have to find a position and, you + + align:start position:0% +You have to find a position and, you + + + align:start position:0% +You have to find a position and, you +know, position and orientation + + align:start position:0% +know, position and orientation + + + align:start position:0% +know, position and orientation +trajectory that will maneuver your big + + align:start position:0% +trajectory that will maneuver your big + + + align:start position:0% +trajectory that will maneuver your big +piano through a world of obstacles. It's + + align:start position:0% +piano through a world of obstacles. It's + + + align:start position:0% +piano through a world of obstacles. It's +just like going up the stairs with your + + align:start position:0% +just like going up the stairs with your + + + align:start position:0% +just like going up the stairs with your +with your uh couch, + + align:start position:0% +with your uh couch, + + + align:start position:0% +with your uh couch, +uh, you know, marking the walls and + + align:start position:0% +uh, you know, marking the walls and + + + align:start position:0% +uh, you know, marking the walls and +bending your couch as you go. Okay. And + + align:start position:0% +bending your couch as you go. Okay. And + + + align:start position:0% +bending your couch as you go. Okay. And +that's sort of the the um some of the + + align:start position:0% +that's sort of the the um some of the + + + align:start position:0% +that's sort of the the um some of the +driving problems in uh in the motion + + align:start position:0% +driving problems in uh in the motion + + + align:start position:0% +driving problems in uh in the motion +planning space. So it's things like that + + align:start position:0% +planning space. So it's things like that + + + align:start position:0% +planning space. So it's things like that +finding a collision free path for a + + align:start position:0% +finding a collision free path for a + + + align:start position:0% +finding a collision free path for a +complicated geometry uh through a an + + align:start position:0% +complicated geometry uh through a an + + + align:start position:0% +complicated geometry uh through a an +obstacle + + align:start position:0% +obstacle + + + align:start position:0% +obstacle +um based + + align:start position:0% +um based + + + align:start position:0% +um based +environment. Okay, just trying to give + + align:start position:0% +environment. Okay, just trying to give + + + align:start position:0% +environment. Okay, just trying to give +you a little culture here. There's and + + align:start position:0% +you a little culture here. There's and + + + align:start position:0% +you a little culture here. There's and +and in that world um one of the most + + align:start position:0% +and in that world um one of the most + + + align:start position:0% +and in that world um one of the most +important concepts I think is the uh is + + align:start position:0% +important concepts I think is the uh is + + + align:start position:0% +important concepts I think is the uh is +the configuration space concept. + + align:start position:0% + + + + align:start position:0% + +which actually you know who came up with + + align:start position:0% +which actually you know who came up with + + + align:start position:0% +which actually you know who came up with +configuration + + align:start position:0% +configuration + + + align:start position:0% +configuration +spaces he's sitting right upstairs it's + + align:start position:0% +spaces he's sitting right upstairs it's + + + align:start position:0% +spaces he's sitting right upstairs it's +Tomas Lozano Perez is is I think + + align:start position:0% +Tomas Lozano Perez is is I think + + + align:start position:0% +Tomas Lozano Perez is is I think +credited with configuration space + + align:start position:0% +credited with configuration space + + + align:start position:0% +credited with configuration space +idea and the idea is that these problems + + align:start position:0% +idea and the idea is that these problems + + + align:start position:0% +idea and the idea is that these problems +can get a lot um + + align:start position:0% + + + + align:start position:0% + +simpler let's say I have a + + align:start position:0% + + + + align:start position:0% + +a square robot going through some + + align:start position:0% +a square robot going through some + + + align:start position:0% +a square robot going through some +complicated obstacle + + align:start position:0% + + + + align:start position:0% + +field. + + align:start position:0% +field. + + + align:start position:0% +field. +Um, and I want to find a path from some + + align:start position:0% +Um, and I want to find a path from some + + + align:start position:0% +Um, and I want to find a path from some +start to the goal. + + align:start position:0% + + + + align:start position:0% + +Well, instead of reasoning about um the + + align:start position:0% +Well, instead of reasoning about um the + + + align:start position:0% +Well, instead of reasoning about um the +geometry of this relative to the + + align:start position:0% +geometry of this relative to the + + + align:start position:0% +geometry of this relative to the +geometry of this all the time, the + + align:start position:0% +geometry of this all the time, the + + + align:start position:0% +geometry of this all the time, the +configuration space tells you you should + + align:start position:0% +configuration space tells you you should + + + align:start position:0% +configuration space tells you you should +actually add the volume of this um of + + align:start position:0% +actually add the volume of this um of + + + align:start position:0% +actually add the volume of this um of +your robot to your obstacles, coming up + + align:start position:0% +your robot to your obstacles, coming up + + + align:start position:0% +your robot to your obstacles, coming up +with configuration space obstacles. + + align:start position:0% +with configuration space obstacles. + + + align:start position:0% +with configuration space obstacles. +Yeah, if you if you actually add the + + align:start position:0% +Yeah, if you if you actually add the + + + align:start position:0% +Yeah, if you if you actually add the +volume of your robot to the obstacles, + + align:start position:0% +volume of your robot to the obstacles, + + + align:start position:0% +volume of your robot to the obstacles, +I'm doing this very um hand wavy here, + + align:start position:0% + + + + align:start position:0% + +but then you can turn the problem of + + align:start position:0% +but then you can turn the problem of + + + align:start position:0% +but then you can turn the problem of +finding a a big geometry through another + + align:start position:0% +finding a a big geometry through another + + + align:start position:0% +finding a a big geometry through another +geometric field to taking a point and + + align:start position:0% +geometric field to taking a point and + + + align:start position:0% +geometric field to taking a point and +driving it through the the geometric + + align:start position:0% +driving it through the the geometric + + + align:start position:0% +driving it through the the geometric +field. And that's a a critical critical + + align:start position:0% +field. And that's a a critical critical + + + align:start position:0% +field. And that's a a critical critical +idea in the world of kinematic motion + + align:start position:0% +idea in the world of kinematic motion + + + align:start position:0% +idea in the world of kinematic motion +planning. + + align:start position:0% + + + + align:start position:0% + +We don't really care about kinematic + + align:start position:0% +We don't really care about kinematic + + + align:start position:0% +We don't really care about kinematic +motion planning uh in this class, right? + + align:start position:0% +motion planning uh in this class, right? + + + align:start position:0% +motion planning uh in this class, right? +We've got enough troubles without + + align:start position:0% +We've got enough troubles without + + + align:start position:0% +We've got enough troubles without +obstacles. We just care about having + + align:start position:0% +obstacles. We just care about having + + + align:start position:0% +obstacles. We just care about having +interesting dynamical system uh to move + + align:start position:0% +interesting dynamical system uh to move + + + align:start position:0% +interesting dynamical system uh to move +around. Okay? + + align:start position:0% +around. Okay? + + + align:start position:0% +around. Okay? +So the things we're talking about uh in + + align:start position:0% +So the things we're talking about uh in + + + align:start position:0% +So the things we're talking about uh in +this class fall under the + + align:start position:0% +this class fall under the + + + align:start position:0% +this class fall under the +heading + + align:start position:0% +heading + + + align:start position:0% +heading +ko + + align:start position:0% +ko + + + align:start position:0% +ko +dynamic motion planning. + + align:start position:0% + + + + align:start position:0% + +And of course the uh the non-holinomic + + align:start position:0% + + + + align:start position:0% + +uh motion planning ideas are are very + + align:start position:0% +uh motion planning ideas are are very + + + align:start position:0% +uh motion planning ideas are are very +related + + align:start position:0% + + + + align:start position:0% + +too. + + align:start position:0% +too. + + + align:start position:0% +too. +Okay. We care about the dynamics. care + + align:start position:0% +Okay. We care about the dynamics. care + + + align:start position:0% +Okay. We care about the dynamics. care +about things that are forced to follow + + align:start position:0% +about things that are forced to follow + + + align:start position:0% +about things that are forced to follow +some trajectories like non-alomic + + align:start position:0% +some trajectories like non-alomic + + + align:start position:0% +some trajectories like non-alomic +systems are + + align:start position:0% + + + + align:start position:0% + +too. Okay. So, if you're out there + + align:start position:0% +too. Okay. So, if you're out there + + + align:start position:0% +too. Okay. So, if you're out there +seeing papers and talks and everything + + align:start position:0% +seeing papers and talks and everything + + + align:start position:0% +seeing papers and talks and everything +about motion planning, I just want you + + align:start position:0% +about motion planning, I just want you + + + align:start position:0% +about motion planning, I just want you +to to sort of see that they're they're + + align:start position:0% +to to sort of see that they're they're + + + align:start position:0% +to to sort of see that they're they're +certainly related to the optimal control + + align:start position:0% +certainly related to the optimal control + + + align:start position:0% +certainly related to the optimal control +things we've talked about, but sometimes + + align:start position:0% +things we've talked about, but sometimes + + + align:start position:0% +things we've talked about, but sometimes +they let go of optimality. + + align:start position:0% +they let go of optimality. + + + align:start position:0% +they let go of optimality. +They're often about kinematics, but + + align:start position:0% +They're often about kinematics, but + + + align:start position:0% +They're often about kinematics, but +there's a good subset of them, which is + + align:start position:0% +there's a good subset of them, which is + + + align:start position:0% +there's a good subset of them, which is +thinking about exactly the problems we + + align:start position:0% +thinking about exactly the problems we + + + align:start position:0% +thinking about exactly the problems we +care about with these kenodnamic motion + + align:start position:0% +care about with these kenodnamic motion + + + align:start position:0% +care about with these kenodnamic motion +planning. Excellent. Okay, so now let's + + align:start position:0% +planning. Excellent. Okay, so now let's + + + align:start position:0% +planning. Excellent. Okay, so now let's +do some motion planning. The culture is + + align:start position:0% +do some motion planning. The culture is + + + align:start position:0% +do some motion planning. The culture is +there. + + align:start position:0% + + + + align:start position:0% + +Um when we did dynamic programming, I + + align:start position:0% +Um when we did dynamic programming, I + + + align:start position:0% +Um when we did dynamic programming, I +already sort of forced upon you the idea + + align:start position:0% +already sort of forced upon you the idea + + + align:start position:0% +already sort of forced upon you the idea +that we could potentially at great cost + + align:start position:0% +that we could potentially at great cost + + + align:start position:0% +that we could potentially at great cost +uh discretize our system and state and + + align:start position:0% +uh discretize our system and state and + + + align:start position:0% +uh discretize our system and state and +actions potentially. So let's do the + + align:start position:0% +actions potentially. So let's do the + + + align:start position:0% +actions potentially. So let's do the +same thing when we start off with motion + + align:start position:0% +same thing when we start off with motion + + + align:start position:0% +same thing when we start off with motion +planning and start with discrete um + + align:start position:0% +planning and start with discrete um + + + align:start position:0% +planning and start with discrete um +planning algorithms. + + align:start position:0% + + + + align:start position:0% + +So let's say we've got our our uh phase + + align:start position:0% +So let's say we've got our our uh phase + + + align:start position:0% +So let's say we've got our our uh phase +plot of our simple pendulum and we're + + align:start position:0% +plot of our simple pendulum and we're + + + align:start position:0% +plot of our simple pendulum and we're +going to just for for kicks right now + + align:start position:0% +going to just for for kicks right now + + + align:start position:0% +going to just for for kicks right now +let's just start off with the trivial + + align:start position:0% +let's just start off with the trivial + + + align:start position:0% +let's just start off with the trivial +discretization. Let's say we're going to + + align:start position:0% +discretization. Let's say we're going to + + + align:start position:0% +discretization. Let's say we're going to +bin up our space like this. + + align:start position:0% + + + + align:start position:0% + +call each one of those a + + align:start position:0% +call each one of those a + + + align:start position:0% +call each one of those a +state, right? And try to start talking + + align:start position:0% +state, right? And try to start talking + + + align:start position:0% +state, right? And try to start talking +about um a graphbased representation of + + align:start position:0% +about um a graphbased representation of + + + align:start position:0% +about um a graphbased representation of +the dynamics of the + + align:start position:0% + + + + align:start position:0% + +system that tries to find a path. Let's + + align:start position:0% +system that tries to find a path. Let's + + + align:start position:0% +system that tries to find a path. Let's +say from our initial + + align:start position:0% + + + + align:start position:0% + +state to some goal + + align:start position:0% + + + + align:start position:0% + +state, right? This isn't the only way to + + align:start position:0% +state, right? This isn't the only way to + + + align:start position:0% +state, right? This isn't the only way to +do discretization, but it's a good way + + align:start position:0% +do discretization, but it's a good way + + + align:start position:0% +do discretization, but it's a good way +to start thinking about it. + + align:start position:0% +to start thinking about it. + + + align:start position:0% +to start thinking about it. +Okay, so that turns the problem into + + align:start position:0% +Okay, so that turns the problem into + + + align:start position:0% +Okay, so that turns the problem into +some + + align:start position:0% +some + + + align:start position:0% +some +uh graphical + + align:start position:0% + + + + align:start position:0% + +model where the control actions + + align:start position:0% +model where the control actions + + + align:start position:0% +model where the control actions +determine our our state transitions and + + align:start position:0% +determine our our state transitions and + + + align:start position:0% +determine our our state transitions and +I like to actually call them S and A in + + align:start position:0% +I like to actually call them S and A in + + + align:start position:0% +I like to actually call them S and A in +the discrete world. + + align:start position:0% + + + + align:start position:0% + +Okay, so people know a lot about doing + + align:start position:0% +Okay, so people know a lot about doing + + + align:start position:0% +Okay, so people know a lot about doing +search on a graph and I'm certainly not + + align:start position:0% +search on a graph and I'm certainly not + + + align:start position:0% +search on a graph and I'm certainly not +going to I don't want to bore you with + + align:start position:0% +going to I don't want to bore you with + + + align:start position:0% +going to I don't want to bore you with +it, but I want to at least know the + + align:start position:0% +it, but I want to at least know the + + + align:start position:0% +it, but I want to at least know the +algorithms that are out there and be + + align:start position:0% +algorithms that are out there and be + + + align:start position:0% +algorithms that are out there and be +able to call upon them if you uh uh if + + align:start position:0% +able to call upon them if you uh uh if + + + align:start position:0% +able to call upon them if you uh uh if +they become useful. + + align:start position:0% +they become useful. + + + align:start position:0% +they become useful. +Okay, so let's say we've we've butchered + + align:start position:0% +Okay, so let's say we've we've butchered + + + align:start position:0% +Okay, so let's say we've we've butchered +up our system like this and we wanted to + + align:start position:0% +up our system like this and we wanted to + + + align:start position:0% +up our system like this and we wanted to +do uh we want to find a path from some + + align:start position:0% +do uh we want to find a path from some + + + align:start position:0% +do uh we want to find a path from some +starting discrete state to some goal + + align:start position:0% +starting discrete state to some goal + + + align:start position:0% +starting discrete state to some goal +state with a with a discrete set of + + align:start position:0% +state with a with a discrete set of + + + align:start position:0% +state with a with a discrete set of +actions. How can we do that? + + align:start position:0% + + + + align:start position:0% + +Off the shelf search. + + align:start position:0% +Off the shelf search. + + + align:start position:0% +Off the shelf search. +AAR is a perfect example. Yep. Dynamic + + align:start position:0% +AAR is a perfect example. Yep. Dynamic + + + align:start position:0% +AAR is a perfect example. Yep. Dynamic +programming is is on the table too, + + align:start position:0% +programming is is on the table too, + + + align:start position:0% +programming is is on the table too, +right? The dynamic programming. That's + + align:start position:0% +right? The dynamic programming. That's + + + align:start position:0% +right? The dynamic programming. That's +actually the way I the reason I drew + + align:start position:0% +actually the way I the reason I drew + + + align:start position:0% +actually the way I the reason I drew +that picture before is because we talked + + align:start position:0% +that picture before is because we talked + + + align:start position:0% +that picture before is because we talked +about that as a way to think about + + align:start position:0% +about that as a way to think about + + + align:start position:0% +about that as a way to think about +dynamic programming. Yeah. + + align:start position:0% +dynamic programming. Yeah. + + + align:start position:0% +dynamic programming. Yeah. +And dynamic programming is incredibly + + align:start position:0% +And dynamic programming is incredibly + + + align:start position:0% +And dynamic programming is incredibly +efficient if what you care about is + + align:start position:0% +efficient if what you care about is + + + align:start position:0% +efficient if what you care about is +knowing the optimal feedback policy, + + align:start position:0% +knowing the optimal feedback policy, + + + align:start position:0% +knowing the optimal feedback policy, +right? The the how to get to the goal + + align:start position:0% +right? The the how to get to the goal + + + align:start position:0% +right? The the how to get to the goal +from every possible initial + + align:start position:0% +from every possible initial + + + align:start position:0% +from every possible initial +state. + + align:start position:0% +state. + + + align:start position:0% +state. +Yeah. If what you care about I mean the + + align:start position:0% +Yeah. If what you care about I mean the + + + align:start position:0% +Yeah. If what you care about I mean the +problem with that is if you have to look + + align:start position:0% +problem with that is if you have to look + + + align:start position:0% +problem with that is if you have to look +at every single initial state then it's + + align:start position:0% +at every single initial state then it's + + + align:start position:0% +at every single initial state then it's +not going to scale to high dimensions + + align:start position:0% +not going to scale to high dimensions + + + align:start position:0% +not going to scale to high dimensions +because there's going to be a lot of + + align:start position:0% +because there's going to be a lot of + + + align:start position:0% +because there's going to be a lot of +states. If you have a slightly higher + + align:start position:0% +states. If you have a slightly higher + + + align:start position:0% +states. If you have a slightly higher +dimensional system and you want to find + + align:start position:0% +dimensional system and you want to find + + + align:start position:0% +dimensional system and you want to find +a start to the goal but just a single + + align:start position:0% +a start to the goal but just a single + + + align:start position:0% +a start to the goal but just a single +path, you don't care about every + + align:start position:0% +path, you don't care about every + + + align:start position:0% +path, you don't care about every +possible state, then you can do not + + align:start position:0% +possible state, then you can do not + + + align:start position:0% +possible state, then you can do not +better than dynamic programming, but you + + align:start position:0% +better than dynamic programming, but you + + + align:start position:0% +better than dynamic programming, but you +can be more selective with your um with + + align:start position:0% +can be more selective with your um with + + + align:start position:0% +can be more selective with your um with +your dynamic programming algorithm um by + + align:start position:0% +your dynamic programming algorithm um by + + + align:start position:0% +your dynamic programming algorithm um by +doing these Dystra type and AAR type + + align:start position:0% +doing these Dystra type and AAR type + + + align:start position:0% +doing these Dystra type and AAR type +algorithms. So, let me just sort of do + + align:start position:0% +algorithms. So, let me just sort of do + + + align:start position:0% +algorithms. So, let me just sort of do +that quickly so you know so you know + + align:start position:0% +that quickly so you know so you know + + + align:start position:0% +that quickly so you know so you know +that that's + + align:start position:0% +that that's + + + align:start position:0% +that that's +there. Okay. + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +So dynamic programming again is + + align:start position:0% +So dynamic programming again is + + + align:start position:0% +So dynamic programming again is +definitely um + + align:start position:0% + + + + align:start position:0% + +uh it's very efficient. It tends it it + + align:start position:0% +uh it's very efficient. It tends it it + + + align:start position:0% +uh it's very efficient. It tends it it +goes to a global + + align:start position:0% + + + + align:start position:0% + +optima. + + align:start position:0% +optima. + + + align:start position:0% +optima. +Um but typically DP is is used to + + align:start position:0% +Um but typically DP is is used to + + + align:start position:0% +Um but typically DP is is used to +describe the the version where you're + + align:start position:0% +describe the the version where you're + + + align:start position:0% +describe the the version where you're +trying to + + align:start position:0% +trying to + + + align:start position:0% +trying to +solve for every state. + + align:start position:0% + + + + align:start position:0% + +simultaneously, + + align:start position:0% +simultaneously, + + + align:start position:0% +simultaneously, +right? You can do a bit better. Um, you + + align:start position:0% +right? You can do a bit better. Um, you + + + align:start position:0% +right? You can do a bit better. Um, you +can be more selective if you just care + + align:start position:0% +can be more selective if you just care + + + align:start position:0% +can be more selective if you just care +about um from a start to a goal x0 to + + align:start position:0% + + + + align:start position:0% + +xg. It's a It's actually a little bit + + align:start position:0% +xg. It's a It's actually a little bit + + + align:start position:0% +xg. It's a It's actually a little bit +surprising to say that I can actually + + align:start position:0% +surprising to say that I can actually + + + align:start position:0% +surprising to say that I can actually +find my path from from a start to a goal + + align:start position:0% +find my path from from a start to a goal + + + align:start position:0% +find my path from from a start to a goal +and know that I'm at a global + + align:start position:0% +and know that I'm at a global + + + align:start position:0% +and know that I'm at a global +optima without ever expanding every + + align:start position:0% +optima without ever expanding every + + + align:start position:0% +optima without ever expanding every +single + + align:start position:0% + + + + align:start position:0% + +node, right? + + align:start position:0% + + + + align:start position:0% + +Okay. And then sometimes we don't even + + align:start position:0% +Okay. And then sometimes we don't even + + + align:start position:0% +Okay. And then sometimes we don't even +care about optimality at all. Like I + + align:start position:0% +care about optimality at all. Like I + + + align:start position:0% +care about optimality at all. Like I +said for some of these algorithms are + + align:start position:0% +said for some of these algorithms are + + + align:start position:0% +said for some of these algorithms are +just trying to find any old path to the + + align:start position:0% +just trying to find any old path to the + + + align:start position:0% +just trying to find any old path to the +goal. And then you can certainly imagine + + align:start position:0% +goal. And then you can certainly imagine + + + align:start position:0% +goal. And then you can certainly imagine +uh finding your path to the goal without + + align:start position:0% +uh finding your path to the goal without + + + align:start position:0% +uh finding your path to the goal without +expanding every possible + + align:start position:0% + + + + align:start position:0% + +node. Okay. So, + + align:start position:0% + + + + align:start position:0% + +um, they all have a very simple recipe. + + align:start position:0% +um, they all have a very simple recipe. + + + align:start position:0% +um, they all have a very simple recipe. +Basically, you keep a a prioritized Q. + + align:start position:0% + + + + align:start position:0% + +How many people know what a prioritized + + align:start position:0% +How many people know what a prioritized + + + align:start position:0% +How many people know what a prioritized +Q is? I should say it's often called Q, + + align:start position:0% +Q is? I should say it's often called Q, + + + align:start position:0% +Q is? I should say it's often called Q, +but it means Q. Yeah, it's another sleep + + align:start position:0% +but it means Q. Yeah, it's another sleep + + + align:start position:0% +but it means Q. Yeah, it's another sleep +deprivation thing + + align:start position:0% +deprivation thing + + + align:start position:0% +deprivation thing +there. Okay. So, I prioritize Q as a + + align:start position:0% +there. Okay. So, I prioritize Q as a + + + align:start position:0% +there. Okay. So, I prioritize Q as a +data structure that we use in computer + + align:start position:0% +data structure that we use in computer + + + align:start position:0% +data structure that we use in computer +science to um um that I'll I'll describe + + align:start position:0% +science to um um that I'll I'll describe + + + align:start position:0% +science to um um that I'll I'll describe +quickly here. So + + align:start position:0% +quickly here. So + + + align:start position:0% +quickly here. So +um we basically have a list of nodes + + align:start position:0% +um we basically have a list of nodes + + + align:start position:0% +um we basically have a list of nodes +that we that we want to consider + + align:start position:0% +that we that we want to consider + + + align:start position:0% +that we that we want to consider +expanding next stored in some list. + + align:start position:0% +expanding next stored in some list. + + + align:start position:0% +expanding next stored in some list. +Okay. But there but they're stored in + + align:start position:0% +Okay. But there but they're stored in + + + align:start position:0% +Okay. But there but they're stored in +that list in an ordered fashion ordered + + align:start position:0% +that list in an ordered fashion ordered + + + align:start position:0% +that list in an ordered fashion ordered +by how likely it is that we want to uh + + align:start position:0% +by how likely it is that we want to uh + + + align:start position:0% +by how likely it is that we want to uh +uh to to check that node next. + + align:start position:0% +uh to to check that node next. + + + align:start position:0% +uh to to check that node next. +Depending on the ways that you add nodes + + align:start position:0% +Depending on the ways that you add nodes + + + align:start position:0% +Depending on the ways that you add nodes +into the prioritized queue, you can do + + align:start position:0% +into the prioritized queue, you can do + + + align:start position:0% +into the prioritized queue, you can do +um any number of the standard + + align:start position:0% +um any number of the standard + + + align:start position:0% +um any number of the standard +um algorithms. The breadth + + align:start position:0% +um algorithms. The breadth + + + align:start position:0% +um algorithms. The breadth +first search, the depth first + + align:start position:0% + + + + align:start position:0% + +search. Dystras. Let me make sure I + + align:start position:0% +search. Dystras. Let me make sure I + + + align:start position:0% +search. Dystras. Let me make sure I +spell it right. It's DJI, right? + + align:start position:0% + + + + align:start position:0% + +What is it? Dig. Okay, good. + + align:start position:0% + + + + align:start position:0% + +Thanks. Um, and you could do a star, + + align:start position:0% +Thanks. Um, and you could do a star, + + + align:start position:0% +Thanks. Um, and you could do a star, +let's say. There's more. There's + + align:start position:0% +let's say. There's more. There's + + + align:start position:0% +let's say. There's more. There's +iterative deepening things like this. + + align:start position:0% +iterative deepening things like this. + + + align:start position:0% +iterative deepening things like this. +Okay, they all go basically like this, + + align:start position:0% +Okay, they all go basically like this, + + + align:start position:0% +Okay, they all go basically like this, +right? I take my um my I have a queue of + + align:start position:0% +right? I take my um my I have a queue of + + + align:start position:0% +right? I take my um my I have a queue of +things I'm about to explore. I start off + + align:start position:0% +things I'm about to explore. I start off + + + align:start position:0% +things I'm about to explore. I start off +with the starting config, the starting + + align:start position:0% +with the starting config, the starting + + + align:start position:0% +with the starting config, the starting +state. I put that in my que. Okay, next + + align:start position:0% +state. I put that in my que. Okay, next + + + align:start position:0% +state. I put that in my que. Okay, next +step of the algorithm, take something + + align:start position:0% +step of the algorithm, take something + + + align:start position:0% +step of the algorithm, take something +out of the queue, consider its children, + + align:start position:0% +out of the queue, consider its children, + + + align:start position:0% +out of the queue, consider its children, +right? And um and then take the first + + align:start position:0% +right? And um and then take the first + + + align:start position:0% +right? And um and then take the first +one out of my priority queue, repeat. + + align:start position:0% +one out of my priority queue, repeat. + + + align:start position:0% +one out of my priority queue, repeat. +Okay, if I consider the children in a + + align:start position:0% +Okay, if I consider the children in a + + + align:start position:0% +Okay, if I consider the children in a +first in first out kind of way, if I add + + align:start position:0% +first in first out kind of way, if I add + + + align:start position:0% +first in first out kind of way, if I add +nodes and just say as soon as I uh as + + align:start position:0% +nodes and just say as soon as I uh as + + + align:start position:0% +nodes and just say as soon as I uh as +soon as I pick up a node, I'm going to + + align:start position:0% +soon as I pick up a node, I'm going to + + + align:start position:0% +soon as I pick up a node, I'm going to +go ahead and stick um those nodes into + + align:start position:0% +go ahead and stick um those nodes into + + + align:start position:0% +go ahead and stick um those nodes into +my queue in a sort of an first in first + + align:start position:0% +my queue in a sort of an first in first + + + align:start position:0% +my queue in a sort of an first in first +out kind of way. Then what I'm going to + + align:start position:0% +out kind of way. Then what I'm going to + + + align:start position:0% +out kind of way. Then what I'm going to +do is I'm going to proceed to look for + + align:start position:0% +do is I'm going to proceed to look for + + + align:start position:0% +do is I'm going to proceed to look for +the goal by going here, then here, then + + align:start position:0% +the goal by going here, then here, then + + + align:start position:0% +the goal by going here, then here, then +here, then here, then here, and write + + align:start position:0% +here, then here, then here, and write + + + align:start position:0% +here, then here, then here, and write +down the tree. That's a breath first + + align:start position:0% +down the tree. That's a breath first + + + align:start position:0% +down the tree. That's a breath first +search. If I do a prioritize queue where + + align:start position:0% +search. If I do a prioritize queue where + + + align:start position:0% +search. If I do a prioritize queue where +I when I add the the children, I just do + + align:start position:0% +I when I add the the children, I just do + + + align:start position:0% +I when I add the the children, I just do +a a last in first out. Yeah. Then I'll + + align:start position:0% +a a last in first out. Yeah. Then I'll + + + align:start position:0% +a a last in first out. Yeah. Then I'll +I'll go here, then I'll go here, then + + align:start position:0% +I'll go here, then I'll go here, then + + + align:start position:0% +I'll go here, then I'll go here, then +I'll go here, and I'll go as deep down + + align:start position:0% +I'll go here, and I'll go as deep down + + + align:start position:0% +I'll go here, and I'll go as deep down +the tree as I could possibly do before I + + align:start position:0% +the tree as I could possibly do before I + + + align:start position:0% +the tree as I could possibly do before I +come back and and go down the the other + + align:start position:0% +come back and and go down the the other + + + align:start position:0% +come back and and go down the the other +nodes. If I keep along + + align:start position:0% +nodes. If I keep along + + + align:start position:0% +nodes. If I keep along +um a uh let's call it a cost to come + + align:start position:0% + + + + align:start position:0% + +to differentiate it from the cost to go. + + align:start position:0% +to differentiate it from the cost to go. + + + align:start position:0% +to differentiate it from the cost to go. +Right? If I keep a record of how much + + align:start position:0% +Right? If I keep a record of how much + + + align:start position:0% +Right? If I keep a record of how much +cost I incurred um for my cost function + + align:start position:0% +cost I incurred um for my cost function + + + align:start position:0% +cost I incurred um for my cost function +getting to that node and I always select + + align:start position:0% +getting to that node and I always select + + + align:start position:0% +getting to that node and I always select +to expand the node that would be the + + align:start position:0% +to expand the node that would be the + + + align:start position:0% +to expand the node that would be the +cheapest. Okay, then that's called + + align:start position:0% +cheapest. Okay, then that's called + + + align:start position:0% +cheapest. Okay, then that's called +Dyster's + + align:start position:0% +Dyster's + + + align:start position:0% +Dyster's +algorithm. It's exactly equivalent to to + + align:start position:0% +algorithm. It's exactly equivalent to to + + + align:start position:0% +algorithm. It's exactly equivalent to to +dynamic programming, but it's in the + + align:start position:0% +dynamic programming, but it's in the + + + align:start position:0% +dynamic programming, but it's in the +forward + + align:start position:0% +forward + + + align:start position:0% +forward +sense. Okay, and then a star is a + + align:start position:0% +sense. Okay, and then a star is a + + + align:start position:0% +sense. Okay, and then a star is a +is a even nicer way to do that which + + align:start position:0% +is a even nicer way to do that which + + + align:start position:0% +is a even nicer way to do that which +combines a cost to come + + align:start position:0% + + + + align:start position:0% + +um plus some + + align:start position:0% + + + + align:start position:0% + +heristic. Okay. + + align:start position:0% + + + + align:start position:0% + +My goal is to make sure you guys know + + align:start position:0% +My goal is to make sure you guys know + + + align:start position:0% +My goal is to make sure you guys know +these are out there. There's lots of + + align:start position:0% +these are out there. There's lots of + + + align:start position:0% +these are out there. There's lots of +good easy places to read about um about + + align:start position:0% +good easy places to read about um about + + + align:start position:0% +good easy places to read about um about +these algorithms uh especially Steve + + align:start position:0% +these algorithms uh especially Steve + + + align:start position:0% +these algorithms uh especially Steve +Laval's book. + + align:start position:0% +Laval's book. + + + align:start position:0% +Laval's book. +Okay. The s- the only surprising thing + + align:start position:0% +Okay. The s- the only surprising thing + + + align:start position:0% +Okay. The s- the only surprising thing +really about these algorithms is first + + align:start position:0% +really about these algorithms is first + + + align:start position:0% +really about these algorithms is first +of all that you can often very + + align:start position:0% +of all that you can often very + + + align:start position:0% +of all that you can often very +efficiently find your way to the goal + + align:start position:0% +efficiently find your way to the goal + + + align:start position:0% +efficiently find your way to the goal +without expanding as many nodes as you + + align:start position:0% +without expanding as many nodes as you + + + align:start position:0% +without expanding as many nodes as you +might + + align:start position:0% +might + + + align:start position:0% +might +think. Okay, AAR in particular if you + + align:start position:0% +think. Okay, AAR in particular if you + + + align:start position:0% +think. Okay, AAR in particular if you +can find a good heristic a heristic in + + align:start position:0% +can find a good heristic a heristic in + + + align:start position:0% +can find a good heristic a heristic in +this case is an estimate of the cost to + + align:start position:0% +this case is an estimate of the cost to + + + align:start position:0% +this case is an estimate of the cost to +go a guess at your value um + + align:start position:0% + + + + align:start position:0% + +function. If you can guess your value + + align:start position:0% +function. If you can guess your value + + + align:start position:0% +function. If you can guess your value +function in a way + + align:start position:0% +function in a way + + + align:start position:0% +function in a way +um where you always underestimated again + + align:start position:0% +um where you always underestimated again + + + align:start position:0% +um where you always underestimated again +I'm not going to bore you with all the + + align:start position:0% +I'm not going to bore you with all the + + + align:start position:0% +I'm not going to bore you with all the +details here then actually you can you + + align:start position:0% +details here then actually you can you + + + align:start position:0% +details here then actually you can you +can sometimes expand very few nodes and + + align:start position:0% +can sometimes expand very few nodes and + + + align:start position:0% +can sometimes expand very few nodes and +find your way right to the goal very + + align:start position:0% +find your way right to the goal very + + + align:start position:0% +find your way right to the goal very +efficient + + align:start position:0% + + + + align:start position:0% + +algorithms. + + align:start position:0% + + + + align:start position:0% + +Okay, people out here use AAR all the + + align:start position:0% +Okay, people out here use AAR all the + + + align:start position:0% +Okay, people out here use AAR all the +time, right? For uh for the Grand + + align:start position:0% +time, right? For uh for the Grand + + + align:start position:0% +time, right? For uh for the Grand +Challenge, I think half the teams had + + align:start position:0% +Challenge, I think half the teams had + + + align:start position:0% +Challenge, I think half the teams had +AAR planners running on their their + + align:start position:0% +AAR planners running on their their + + + align:start position:0% +AAR planners running on their their +vehicle, right? For Little Dog, uh in + + align:start position:0% +vehicle, right? For Little Dog, uh in + + + align:start position:0% +vehicle, right? For Little Dog, uh in +our, you know, we're picking footholds + + align:start position:0% +our, you know, we're picking footholds + + + align:start position:0% +our, you know, we're picking footholds +to get from the start to the goal. We + + align:start position:0% +to get from the start to the goal. We + + + align:start position:0% +to get from the start to the goal. We +have an AAR planner in there, discreet + + align:start position:0% +have an AAR planner in there, discreet + + + align:start position:0% +have an AAR planner in there, discreet +time planners. These things are are + + align:start position:0% +time planners. These things are are + + + align:start position:0% +time planners. These things are are +real. They're good. They're fast. Um, if + + align:start position:0% +real. They're good. They're fast. Um, if + + + align:start position:0% +real. They're good. They're fast. Um, if +you can find a good heristic, they can + + align:start position:0% +you can find a good heristic, they can + + + align:start position:0% +you can find a good heristic, they can +be very, very efficient. If you care + + align:start position:0% +be very, very efficient. If you care + + + align:start position:0% +be very, very efficient. If you care +about a continuous time, a continuous + + align:start position:0% +about a continuous time, a continuous + + + align:start position:0% +about a continuous time, a continuous +state, continuous action plan that gets + + align:start position:0% +state, continuous action plan that gets + + + align:start position:0% +state, continuous action plan that gets +me from the goal, then they're not as + + align:start position:0% +me from the goal, then they're not as + + + align:start position:0% +me from the goal, then they're not as +satisfying because they relied on this + + align:start position:0% +satisfying because they relied on this + + + align:start position:0% +satisfying because they relied on this +discretization. Okay, but again, + + align:start position:0% +discretization. Okay, but again, + + + align:start position:0% +discretization. Okay, but again, +um, so we know when we're discretizing + + align:start position:0% +um, so we know when we're discretizing + + + align:start position:0% +um, so we know when we're discretizing +this thing, we're going to have some + + align:start position:0% +this thing, we're going to have some + + + align:start position:0% +this thing, we're going to have some +problems, right? We're going to um I'm + + align:start position:0% +problems, right? We're going to um I'm + + + align:start position:0% +problems, right? We're going to um I'm +going to just assume that there's a + + align:start position:0% +going to just assume that there's a + + + align:start position:0% +going to just assume that there's a +control action that gets me sort of + + align:start position:0% +control action that gets me sort of + + + align:start position:0% +control action that gets me sort of +squarely in the center of this um this + + align:start position:0% +squarely in the center of this um this + + + align:start position:0% +squarely in the center of this um this +next discretized cell and then go like + + align:start position:0% +next discretized cell and then go like + + + align:start position:0% +next discretized cell and then go like +this. If I were to execute out my + + align:start position:0% +this. If I were to execute out my + + + align:start position:0% +this. If I were to execute out my +actions from my discrete planning + + align:start position:0% +actions from my discrete planning + + + align:start position:0% +actions from my discrete planning +algorithm on the continuous time system, + + align:start position:0% +algorithm on the continuous time system, + + + align:start position:0% +algorithm on the continuous time system, +I'm going to quickly deviate from my + + align:start position:0% +I'm going to quickly deviate from my + + + align:start position:0% +I'm going to quickly deviate from my +plan. But these things are an excellent + + align:start position:0% +plan. But these things are an excellent + + + align:start position:0% +plan. But these things are an excellent +way to start to seed something like a + + align:start position:0% +way to start to seed something like a + + + align:start position:0% +way to start to seed something like a +direct collocation method, right? Find + + align:start position:0% +direct collocation method, right? Find + + + align:start position:0% +direct collocation method, right? Find +yourself a feasible optimal plan and + + align:start position:0% +yourself a feasible optimal plan and + + + align:start position:0% +yourself a feasible optimal plan and +then stabilize it. Let's say with the + + align:start position:0% +then stabilize it. Let's say with the + + + align:start position:0% +then stabilize it. Let's say with the +LTV + + align:start position:0% +LTV + + + align:start position:0% +LTV +feedback. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% + + + + align:start position:0% + +Good. So that world of planning + + align:start position:0% +Good. So that world of planning + + + align:start position:0% +Good. So that world of planning +algorithms is out there. + + align:start position:0% + + + + align:start position:0% + +But about I don't know 10 years ago now + + align:start position:0% +But about I don't know 10 years ago now + + + align:start position:0% +But about I don't know 10 years ago now +something big happened in robotic motion + + align:start position:0% +something big happened in robotic motion + + + align:start position:0% +something big happened in robotic motion +planning world. Um people started using + + align:start position:0% +planning world. Um people started using + + + align:start position:0% +planning world. Um people started using +uh sample based motion planning + + align:start position:0% +uh sample based motion planning + + + align:start position:0% +uh sample based motion planning +algorithms + + align:start position:0% +algorithms + + + align:start position:0% +algorithms +and there was sort of a revolution in + + align:start position:0% +and there was sort of a revolution in + + + align:start position:0% +and there was sort of a revolution in +people using motion planning in + + align:start position:0% +people using motion planning in + + + align:start position:0% +people using motion planning in +robotics. Okay. + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +It's also sometimes called randomized + + align:start position:0% +It's also sometimes called randomized + + + align:start position:0% +It's also sometimes called randomized +motion + + align:start position:0% + + + + align:start position:0% + +planning. And these we are going to dig + + align:start position:0% +planning. And these we are going to dig + + + align:start position:0% +planning. And these we are going to dig +a little deeper in because they're I + + align:start position:0% +a little deeper in because they're I + + + align:start position:0% +a little deeper in because they're I +think they're a we use them all the + + align:start position:0% +think they're a we use them all the + + + align:start position:0% +think they're a we use them all the +time. I think they're an important class + + align:start position:0% +time. I think they're an important class + + + align:start position:0% +time. I think they're an important class +of algorithms. Okay. Okay. So, two of + + align:start position:0% +of algorithms. Okay. Okay. So, two of + + + align:start position:0% +of algorithms. Okay. Okay. So, two of +the most notable um sample based motion + + align:start position:0% +the most notable um sample based motion + + + align:start position:0% +the most notable um sample based motion +planning um ideas are the rapidly + + align:start position:0% + + + + align:start position:0% + +exploring randomized + + align:start position:0% + + + + align:start position:0% + +trees and the probabilistic road map. + + align:start position:0% + + + + align:start position:0% + +Another poll. How many people know about + + align:start position:0% +Another poll. How many people know about + + + align:start position:0% +Another poll. How many people know about +RTS? + + align:start position:0% +RTS? + + + align:start position:0% +RTS? +Awesome. How many people about know + + align:start position:0% +Awesome. How many people about know + + + align:start position:0% +Awesome. How many people about know +about PRM? Awesome. Okay. + + align:start position:0% + + + + align:start position:0% + +They're pretty related to each other. + + align:start position:0% +They're pretty related to each other. + + + align:start position:0% +They're pretty related to each other. +Let's talk about rapidly exploring + + align:start position:0% +Let's talk about rapidly exploring + + + align:start position:0% +Let's talk about rapidly exploring +randomized trees + + align:start position:0% +randomized trees + + + align:start position:0% +randomized trees +first. + + align:start position:0% +first. + + + align:start position:0% +first. +Okay, so both of these are an attempt to + + align:start position:0% +Okay, so both of these are an attempt to + + + align:start position:0% +Okay, so both of these are an attempt to +get away from these very coarse um + + align:start position:0% +get away from these very coarse um + + + align:start position:0% +get away from these very coarse um +discretizations like this and sort of + + align:start position:0% +discretizations like this and sort of + + + align:start position:0% +discretizations like this and sort of +embrace the fact that we're working in a + + align:start position:0% +embrace the fact that we're working in a + + + align:start position:0% +embrace the fact that we're working in a +continuous state + + align:start position:0% +continuous state + + + align:start position:0% +continuous state +space. Okay, instead of discretizing it + + align:start position:0% +space. Okay, instead of discretizing it + + + align:start position:0% +space. Okay, instead of discretizing it +at at some known sites, we're going to + + align:start position:0% +at at some known sites, we're going to + + + align:start position:0% +at at some known sites, we're going to +discretise sort of at randomly chosen + + align:start position:0% +discretise sort of at randomly chosen + + + align:start position:0% +discretise sort of at randomly chosen +samples. Okay? And as we add more and + + align:start position:0% +samples. Okay? And as we add more and + + + align:start position:0% +samples. Okay? And as we add more and +more samples, we're going to worry less + + align:start position:0% +more samples, we're going to worry less + + + align:start position:0% +more samples, we're going to worry less +and less about the discretization, + + align:start position:0% +and less about the discretization, + + + align:start position:0% +and less about the discretization, +right? And eventually we're going to + + align:start position:0% +right? And eventually we're going to + + + align:start position:0% +right? And eventually we're going to +have some nice to say about the + + align:start position:0% +have some nice to say about the + + + align:start position:0% +have some nice to say about the +continuous + + align:start position:0% +continuous + + + align:start position:0% +continuous +space. So the rapidly exploring + + align:start position:0% +space. So the rapidly exploring + + + align:start position:0% +space. So the rapidly exploring +randomized trees, the RRTs are a very + + align:start position:0% +randomized trees, the RRTs are a very + + + align:start position:0% +randomized trees, the RRTs are a very +simple algorithm to explain. + + align:start position:0% + + + + align:start position:0% + +Okay, let's think about it in terms of + + align:start position:0% +Okay, let's think about it in terms of + + + align:start position:0% +Okay, let's think about it in terms of +moving a piano through a a 2D piano + + align:start position:0% +moving a piano through a a 2D piano + + + align:start position:0% +moving a piano through a a 2D piano +through a a 2D world in configuration + + align:start position:0% +through a a 2D world in configuration + + + align:start position:0% +through a a 2D world in configuration +space. So, we got a point moving through + + align:start position:0% +space. So, we got a point moving through + + + align:start position:0% +space. So, we got a point moving through +a a world. It should really be 3D + + align:start position:0% +a a world. It should really be 3D + + + align:start position:0% +a a world. It should really be 3D +actually if there's an orientation to + + align:start position:0% +actually if there's an orientation to + + + align:start position:0% +actually if there's an orientation to +the piano, but let's let's just look at + + align:start position:0% +the piano, but let's let's just look at + + + align:start position:0% +the piano, but let's let's just look at +the 2D problem here. So, + + align:start position:0% +the 2D problem here. So, + + + align:start position:0% +the 2D problem here. So, +um so I've got a point + + align:start position:0% +um so I've got a point + + + align:start position:0% +um so I've got a point +um an initial state, an initial goal in + + align:start position:0% +um an initial state, an initial goal in + + + align:start position:0% +um an initial state, an initial goal in +a 2D + + align:start position:0% + + + + align:start position:0% + +world. Let's call it XY. And I've got + + align:start position:0% +world. Let's call it XY. And I've got + + + align:start position:0% +world. Let's call it XY. And I've got +some + + align:start position:0% + + + + align:start position:0% + +obstacles. I like to find a path from + + align:start position:0% +obstacles. I like to find a path from + + + align:start position:0% +obstacles. I like to find a path from +the start to the goal without explicitly + + align:start position:0% +the start to the goal without explicitly + + + align:start position:0% +the start to the goal without explicitly +discretizing the space. Okay. The RTS do + + align:start position:0% +discretizing the space. Okay. The RTS do + + + align:start position:0% +discretizing the space. Okay. The RTS do +it like this. Pick a point from random + + align:start position:0% +it like this. Pick a point from random + + + align:start position:0% +it like this. Pick a point from random +at the state in the space. Yeah. + + align:start position:0% +at the state in the space. Yeah. + + + align:start position:0% +at the state in the space. Yeah. +try to connect your current tree which + + align:start position:0% +try to connect your current tree which + + + align:start position:0% +try to connect your current tree which +in the initial state is just this x0 to + + align:start position:0% +in the initial state is just this x0 to + + + align:start position:0% +in the initial state is just this x0 to +that um that new point. Okay, if I if I + + align:start position:0% +that um that new point. Okay, if I if I + + + align:start position:0% +that um that new point. Okay, if I if I +uh let's make it exactly clear that I + + align:start position:0% +uh let's make it exactly clear that I + + + align:start position:0% +uh let's make it exactly clear that I +can't do that. Okay, so that's going to + + align:start position:0% +can't do that. Okay, so that's going to + + + align:start position:0% +can't do that. Okay, so that's going to +actually my attempt to directly connect + + align:start position:0% +actually my attempt to directly connect + + + align:start position:0% +actually my attempt to directly connect +this is going to fail because it goes + + align:start position:0% +this is going to fail because it goes + + + align:start position:0% +this is going to fail because it goes +through an obstacle. Okay, so I can't + + align:start position:0% +through an obstacle. Okay, so I can't + + + align:start position:0% +through an obstacle. Okay, so I can't +add that node sample again randomly. + + align:start position:0% +add that node sample again randomly. + + + align:start position:0% +add that node sample again randomly. +Okay, at some point I'll get a node like + + align:start position:0% +Okay, at some point I'll get a node like + + + align:start position:0% +Okay, at some point I'll get a node like +here and I'm going to connect my + + align:start position:0% +here and I'm going to connect my + + + align:start position:0% +here and I'm going to connect my +um I'm going to make a branch of my tree + + align:start position:0% +um I'm going to make a branch of my tree + + + align:start position:0% +um I'm going to make a branch of my tree +that connects those two points. Okay, + + align:start position:0% +that connects those two points. Okay, + + + align:start position:0% +that connects those two points. Okay, +pick a new random point something. Let's + + align:start position:0% +pick a new random point something. Let's + + + align:start position:0% +pick a new random point something. Let's +say you get something here. Now you have + + align:start position:0% +say you get something here. Now you have + + + align:start position:0% +say you get something here. Now you have +to choose between these two random + + align:start position:0% +to choose between these two random + + + align:start position:0% +to choose between these two random +points. Decide decide which is the + + align:start position:0% +points. Decide decide which is the + + + align:start position:0% +points. Decide decide which is the +closest. The closest isn't always an + + align:start position:0% +closest. The closest isn't always an + + + align:start position:0% +closest. The closest isn't always an +easy thing to decide if you have + + align:start position:0% +easy thing to decide if you have + + + align:start position:0% +easy thing to decide if you have +complicated dynamics. In this problem, + + align:start position:0% +complicated dynamics. In this problem, + + + align:start position:0% +complicated dynamics. In this problem, +it's pretty easy. We could just use + + align:start position:0% +it's pretty easy. We could just use + + + align:start position:0% +it's pretty easy. We could just use +something like a ukitian distance. And + + align:start position:0% +something like a ukitian distance. And + + + align:start position:0% +something like a ukitian distance. And +I'll connect it up like this. I get a r + + align:start position:0% +I'll connect it up like this. I get a r + + + align:start position:0% +I'll connect it up like this. I get a r +another random point, I'll connect it up + + align:start position:0% +another random point, I'll connect it up + + + align:start position:0% +another random point, I'll connect it up +like this. I get some random points that + + align:start position:0% +like this. I get some random points that + + + align:start position:0% +like this. I get some random points that +go whatever way. If they end up here, I + + align:start position:0% +go whatever way. If they end up here, I + + + align:start position:0% +go whatever way. If they end up here, I +just throw them out. If they end up + + align:start position:0% +just throw them out. If they end up + + + align:start position:0% +just throw them out. If they end up +something that I can't connect, I'll + + align:start position:0% +something that I can't connect, I'll + + + align:start position:0% +something that I can't connect, I'll +just throw it out. But at some point, + + align:start position:0% +just throw it out. But at some point, + + + align:start position:0% +just throw it out. But at some point, +I'll start filling the space with these + + align:start position:0% +I'll start filling the space with these + + + align:start position:0% +I'll start filling the space with these +these + + align:start position:0% +these + + + align:start position:0% +these +trees. Okay. + + align:start position:0% + + + + align:start position:0% + +Lo and behold, if I do it enough, it + + align:start position:0% +Lo and behold, if I do it enough, it + + + align:start position:0% +Lo and behold, if I do it enough, it +doesn't actually necessarily take that + + align:start position:0% +doesn't actually necessarily take that + + + align:start position:0% +doesn't actually necessarily take that +long until I get up here and and get + + align:start position:0% +long until I get up here and and get + + + align:start position:0% +long until I get up here and and get +close in the vicinity of that goal. + + align:start position:0% +close in the vicinity of that goal. + + + align:start position:0% +close in the vicinity of that goal. +Okay, very simple random algorithm, + + align:start position:0% +Okay, very simple random algorithm, + + + align:start position:0% +Okay, very simple random algorithm, +right? Do you understand how it's sort + + align:start position:0% +right? Do you understand how it's sort + + + align:start position:0% +right? Do you understand how it's sort +of avoiding the the curse of + + align:start position:0% +of avoiding the the curse of + + + align:start position:0% +of avoiding the the curse of +discretization, right? It's just picking + + align:start position:0% +discretization, right? It's just picking + + + align:start position:0% +discretization, right? It's just picking +points at random from this continuous + + align:start position:0% +points at random from this continuous + + + align:start position:0% +points at random from this continuous +space. So there's no um no constraints + + align:start position:0% +space. So there's no um no constraints + + + align:start position:0% +space. So there's no um no constraints +uh no explicit constraints that it lies + + align:start position:0% +uh no explicit constraints that it lies + + + align:start position:0% +uh no explicit constraints that it lies +in some the center of some bucket or + + align:start position:0% +in some the center of some bucket or + + + align:start position:0% +in some the center of some bucket or +something like that right nodes could be + + align:start position:0% +something like that right nodes could be + + + align:start position:0% +something like that right nodes could be +arbitrarily close to each other I can + + align:start position:0% +arbitrarily close to each other I can + + + align:start position:0% +arbitrarily close to each other I can +get arbitrarily fine sort of + + align:start position:0% + + + + align:start position:0% + +discretization + + align:start position:0% +discretization + + + align:start position:0% +discretization +what's really cool what makes these + + align:start position:0% +what's really cool what makes these + + + align:start position:0% +what's really cool what makes these +things tick is that the idea is so + + align:start position:0% +things tick is that the idea is so + + + align:start position:0% +things tick is that the idea is so +simple the code is so easy to write and + + align:start position:0% +simple the code is so easy to write and + + + align:start position:0% +simple the code is so easy to write and +they really really work fast Okay, let + + align:start position:0% +they really really work fast Okay, let + + + align:start position:0% +they really really work fast Okay, let +me + + align:start position:0% +me + + + align:start position:0% +me +just show you that basic example. + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +Okay, this this time I'm going to do it + + align:start position:0% +Okay, this this time I'm going to do it + + + align:start position:0% +Okay, this this time I'm going to do it +even without uh + + align:start position:0% +even without uh + + + align:start position:0% +even without uh +um without any obstacles but just to + + align:start position:0% +um without any obstacles but just to + + + align:start position:0% +um without any obstacles but just to +show you the basic growth of these kind + + align:start position:0% +show you the basic growth of these kind + + + align:start position:0% +show you the basic growth of these kind +of um + + align:start position:0% + + + + align:start position:0% + +planters. + + align:start position:0% + + + + align:start position:0% + +Awesome. Okay. So, + + align:start position:0% +Awesome. Okay. So, + + + align:start position:0% +Awesome. Okay. So, +um my + + align:start position:0% + + + + align:start position:0% + +uh initial condition is just that blue + + align:start position:0% +uh initial condition is just that blue + + + align:start position:0% +uh initial condition is just that blue +point and I'm going to start growing a + + align:start position:0% +point and I'm going to start growing a + + + align:start position:0% +point and I'm going to start growing a +tree in every random direction. There's + + align:start position:0% +tree in every random direction. There's + + + align:start position:0% +tree in every random direction. There's +not even a goal in this problem. This is + + align:start position:0% +not even a goal in this problem. This is + + + align:start position:0% +not even a goal in this problem. This is +just to show you the basic growth of the + + align:start position:0% +just to show you the basic growth of the + + + align:start position:0% +just to show you the basic growth of the +tree. Okay. + + align:start position:0% + + + + align:start position:0% + +Every point I grow at + + align:start position:0% +Every point I grow at + + + align:start position:0% +Every point I grow at +random. Every time I pick a point from a + + align:start position:0% +random. Every time I pick a point from a + + + align:start position:0% +random. Every time I pick a point from a +uniform distribution covering the space, + + align:start position:0% +uniform distribution covering the space, + + + align:start position:0% +uniform distribution covering the space, +I'm going to find the closest point in + + align:start position:0% +I'm going to find the closest point in + + + align:start position:0% +I'm going to find the closest point in +the + + align:start position:0% +the + + + align:start position:0% +the +algorithm and I'm going to grow a + + align:start position:0% +algorithm and I'm going to grow a + + + align:start position:0% +algorithm and I'm going to grow a +closest point on the tree and I'm going + + align:start position:0% +closest point on the tree and I'm going + + + align:start position:0% +closest point on the tree and I'm going +to try to grow my tree towards that um + + align:start position:0% +to try to grow my tree towards that um + + + align:start position:0% +to try to grow my tree towards that um +that + + align:start position:0% +that + + + align:start position:0% +that +node. Yeah, sort of understand what's + + align:start position:0% +node. Yeah, sort of understand what's + + + align:start position:0% +node. Yeah, sort of understand what's +happening there. It's pretty faint, I + + align:start position:0% +happening there. It's pretty faint, I + + + align:start position:0% +happening there. It's pretty faint, I +think, + + align:start position:0% +think, + + + align:start position:0% +think, +but all right. So, watch what happens if + + align:start position:0% +but all right. So, watch what happens if + + + align:start position:0% +but all right. So, watch what happens if +I just let that run. + + align:start position:0% + + + + align:start position:0% + +Okay, trivial algorithm. It has what a + + align:start position:0% +Okay, trivial algorithm. It has what a + + + align:start position:0% +Okay, trivial algorithm. It has what a +lot of people like to call a fractal + + align:start position:0% +lot of people like to call a fractal + + + align:start position:0% +lot of people like to call a fractal +expansion of the uh of the coverage + + align:start position:0% + + + + align:start position:0% + +area. + + align:start position:0% + + + + align:start position:0% + +Okay, this happens if of course if + + align:start position:0% +Okay, this happens if of course if + + + align:start position:0% +Okay, this happens if of course if +there's obstacles it'll take a little + + align:start position:0% +there's obstacles it'll take a little + + + align:start position:0% +there's obstacles it'll take a little +longer to get around there. But the + + align:start position:0% +longer to get around there. But the + + + align:start position:0% +longer to get around there. But the +algorithm probabilistically covers the + + align:start position:0% +algorithm probabilistically covers the + + + align:start position:0% +algorithm probabilistically covers the +state space as I add more and more + + align:start position:0% +state space as I add more and more + + + align:start position:0% +state space as I add more and more +points. Yeah. And it's actually some + + align:start position:0% +points. Yeah. And it's actually some + + + align:start position:0% +points. Yeah. And it's actually some +people call them uh dense trees because + + align:start position:0% +people call them uh dense trees because + + + align:start position:0% +people call them uh dense trees because +they do this. Yeah. + + align:start position:0% + + + + align:start position:0% + +Um if you noticed something about them, + + align:start position:0% +Um if you noticed something about them, + + + align:start position:0% +Um if you noticed something about them, +they have sort of surprisingly nice + + align:start position:0% +they have sort of surprisingly nice + + + align:start position:0% +they have sort of surprisingly nice +qualities. Okay. Um it filled the space + + align:start position:0% +qualities. Okay. Um it filled the space + + + align:start position:0% +qualities. Okay. Um it filled the space +pretty uniformly pretty quickly, right? + + align:start position:0% +pretty uniformly pretty quickly, right? + + + align:start position:0% +pretty uniformly pretty quickly, right? +It didn't just go off in one corner and + + align:start position:0% +It didn't just go off in one corner and + + + align:start position:0% +It didn't just go off in one corner and +start adding nodes on one side, right? + + align:start position:0% +start adding nodes on one side, right? + + + align:start position:0% +start adding nodes on one side, right? +Um or something like that. It actually + + align:start position:0% +Um or something like that. It actually + + + align:start position:0% +Um or something like that. It actually +has a property that people call the the + + align:start position:0% +has a property that people call the the + + + align:start position:0% +has a property that people call the the +voronoi bias. + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +the voronoi region of a graph. + + align:start position:0% +the voronoi region of a graph. + + + align:start position:0% +the voronoi region of a graph. +Well, the voroi bias implies that the + + align:start position:0% +Well, the voroi bias implies that the + + + align:start position:0% +Well, the voroi bias implies that the +tree has a has a um has a bias for + + align:start position:0% +tree has a has a um has a bias for + + + align:start position:0% +tree has a has a um has a bias for +always growing into the biggest open + + align:start position:0% +always growing into the biggest open + + + align:start position:0% +always growing into the biggest open +regions of the of the graph. + + align:start position:0% +regions of the of the graph. + + + align:start position:0% +regions of the of the graph. +Yeah. And that just comes from uni + + align:start position:0% +Yeah. And that just comes from uni + + + align:start position:0% +Yeah. And that just comes from uni +sampling uniformly, right? If I have + + align:start position:0% +sampling uniformly, right? If I have + + + align:start position:0% +sampling uniformly, right? If I have +some um some tree that has a big wide + + align:start position:0% +some um some tree that has a big wide + + + align:start position:0% +some um some tree that has a big wide +open area for whatever + + align:start position:0% +open area for whatever + + + align:start position:0% +open area for whatever +region, then with very high probability, + + align:start position:0% +region, then with very high probability, + + + align:start position:0% +region, then with very high probability, +I'm going to I'm going to pick a point + + align:start position:0% +I'm going to I'm going to pick a point + + + align:start position:0% +I'm going to I'm going to pick a point +that's inside this the biggest region, + + align:start position:0% +that's inside this the biggest region, + + + align:start position:0% +that's inside this the biggest region, +right? And the biggest regions in the + + align:start position:0% +right? And the biggest regions in the + + + align:start position:0% +right? And the biggest regions in the +space are the ones that have the highest + + align:start position:0% +space are the ones that have the highest + + + align:start position:0% +space are the ones that have the highest +probability of being chosen. + + align:start position:0% +probability of being chosen. + + + align:start position:0% +probability of being chosen. +So probabilistically this thing fills + + align:start position:0% +So probabilistically this thing fills + + + align:start position:0% +So probabilistically this thing fills +the biggest spaces the biggest open + + align:start position:0% +the biggest spaces the biggest open + + + align:start position:0% +the biggest spaces the biggest open +spaces in the uh in the search tree. + + align:start position:0% +spaces in the uh in the search tree. + + + align:start position:0% +spaces in the uh in the search tree. +Okay. Just by the virtue of of um of + + align:start position:0% +Okay. Just by the virtue of of um of + + + align:start position:0% +Okay. Just by the virtue of of um of +sampling + + align:start position:0% +sampling + + + align:start position:0% +sampling +uniformly. Okay. So you get these very + + align:start position:0% +uniformly. Okay. So you get these very + + + align:start position:0% +uniformly. Okay. So you get these very +very dense um fast uh + + align:start position:0% + + + + align:start position:0% + +trees. Okay. Okay. And you can imagine + + align:start position:0% +trees. Okay. Okay. And you can imagine + + + align:start position:0% +trees. Okay. Okay. And you can imagine +if there's obstacles or something like + + align:start position:0% +if there's obstacles or something like + + + align:start position:0% +if there's obstacles or something like +that inside there, it's going to work + + align:start position:0% +that inside there, it's going to work + + + align:start position:0% +that inside there, it's going to work +its way just around the obstacles. Yeah. + + align:start position:0% +its way just around the obstacles. Yeah. + + + align:start position:0% +its way just around the obstacles. Yeah. +Does it slow down as you get more and + + align:start position:0% +Does it slow down as you get more and + + + align:start position:0% +Does it slow down as you get more and +more nodes in there? Good. So, so what + + align:start position:0% +more nodes in there? Good. So, so what + + + align:start position:0% +more nodes in there? Good. So, so what +is the computation that goes into it? + + align:start position:0% +is the computation that goes into it? + + + align:start position:0% +is the computation that goes into it? +What's the expensive part of the + + align:start position:0% +What's the expensive part of the + + + align:start position:0% +What's the expensive part of the +computation, would you guess? + + align:start position:0% +computation, would you guess? + + + align:start position:0% +computation, would you guess? +Finding nearest neighbor. Good. Right. + + align:start position:0% +Finding nearest neighbor. Good. Right. + + + align:start position:0% +Finding nearest neighbor. Good. Right. +So, um so yeah, it slows down with the + + align:start position:0% +So, um so yeah, it slows down with the + + + align:start position:0% +So, um so yeah, it slows down with the +nearest neighbor, but not as much as you + + align:start position:0% +nearest neighbor, but not as much as you + + + align:start position:0% +nearest neighbor, but not as much as you +expect. There's actually there's two + + align:start position:0% +expect. There's actually there's two + + + align:start position:0% +expect. There's actually there's two +expensive parts. Only one of the only + + align:start position:0% +expensive parts. Only one of the only + + + align:start position:0% +expensive parts. Only one of the only +the nearest neighbor one shows up here. + + align:start position:0% +the nearest neighbor one shows up here. + + + align:start position:0% +the nearest neighbor one shows up here. +The other one potentially is the + + align:start position:0% +The other one potentially is the + + + align:start position:0% +The other one potentially is the +collision checker and in some + + align:start position:0% +collision checker and in some + + + align:start position:0% +collision checker and in some +complicated systems checking if you're + + align:start position:0% +complicated systems checking if you're + + + align:start position:0% +complicated systems checking if you're +inside a collision in inside a region + + align:start position:0% +inside a collision in inside a region + + + align:start position:0% +inside a collision in inside a region +especially if you're a big robotic arm + + align:start position:0% +especially if you're a big robotic arm + + + align:start position:0% +especially if you're a big robotic arm +or something like that can be actually + + align:start position:0% +or something like that can be actually + + + align:start position:0% +or something like that can be actually +the dominant expensive thing right so um + + align:start position:0% +the dominant expensive thing right so um + + + align:start position:0% +the dominant expensive thing right so um +so these things in mat lab everything's + + align:start position:0% +so these things in mat lab everything's + + + align:start position:0% +so these things in mat lab everything's +vectorized it actually doesn't grow that + + align:start position:0% +vectorized it actually doesn't grow that + + + align:start position:0% +vectorized it actually doesn't grow that +badly with the number of nodes but + + align:start position:0% +badly with the number of nodes but + + + align:start position:0% +badly with the number of nodes but +certainly the the nearest neighbor + + align:start position:0% +certainly the the nearest neighbor + + + align:start position:0% +certainly the the nearest neighbor +calculation gets more and more expensive + + align:start position:0% +calculation gets more and more expensive + + + align:start position:0% +calculation gets more and more expensive +by default it's just checking every + + align:start position:0% +by default it's just checking every + + + align:start position:0% +by default it's just checking every +possible the distance between every it + + align:start position:0% +possible the distance between every it + + + align:start position:0% +possible the distance between every it +the new the sample point and every + + align:start position:0% +the new the sample point and every + + + align:start position:0% +the new the sample point and every +possible node could use like a KD. Yeah. + + align:start position:0% +possible node could use like a KD. Yeah. + + + align:start position:0% +possible node could use like a KD. Yeah. +Good. Yeah. So there there are different + + align:start position:0% +Good. Yeah. So there there are different + + + align:start position:0% +Good. Yeah. So there there are different +um some sort of structures that you can + + align:start position:0% +um some sort of structures that you can + + + align:start position:0% +um some sort of structures that you can +use to to make that look up more more + + align:start position:0% +use to to make that look up more more + + + align:start position:0% +use to to make that look up more more +efficient. + + align:start position:0% + + + + align:start position:0% + +Right. So RTS have gone kind of come in + + align:start position:0% +Right. So RTS have gone kind of come in + + + align:start position:0% +Right. So RTS have gone kind of come in +and and and done things to robotics that + + align:start position:0% +and and and done things to robotics that + + + align:start position:0% +and and and done things to robotics that +uh people hadn't done before. So this is + + align:start position:0% +uh people hadn't done before. So this is + + + align:start position:0% +uh people hadn't done before. So this is +a two-dimensional example. + + align:start position:0% +a two-dimensional example. + + + align:start position:0% +a two-dimensional example. +Um, people would have said before I can + + align:start position:0% +Um, people would have said before I can + + + align:start position:0% +Um, people would have said before I can +do sort of motion planning effectively + + align:start position:0% +do sort of motion planning effectively + + + align:start position:0% +do sort of motion planning effectively +in maybe five or 10 dimensions, a little + + align:start position:0% +in maybe five or 10 dimensions, a little + + + align:start position:0% +in maybe five or 10 dimensions, a little +bit more than I could do with just DP, + + align:start position:0% +bit more than I could do with just DP, + + + align:start position:0% +bit more than I could do with just DP, +but but you know, not a lot more because + + align:start position:0% +but but you know, not a lot more because + + + align:start position:0% +but but you know, not a lot more because +I'm still doing these sort of random + + align:start position:0% +I'm still doing these sort of random + + + align:start position:0% +I'm still doing these sort of random +factorizations. Um, the guys that came + + align:start position:0% +factorizations. Um, the guys that came + + + align:start position:0% +factorizations. Um, the guys that came +out and started doing these RRTs, Laval + + align:start position:0% +out and started doing these RRTs, Laval + + + align:start position:0% +out and started doing these RRTs, Laval +being one of them, Cuffner being another + + align:start position:0% +being one of them, Cuffner being another + + + align:start position:0% +being one of them, Cuffner being another +one, started showing examples of robots + + align:start position:0% +one, started showing examples of robots + + + align:start position:0% +one, started showing examples of robots +with 32 degrees of freedom doing pretty + + align:start position:0% +with 32 degrees of freedom doing pretty + + + align:start position:0% +with 32 degrees of freedom doing pretty +complicated plans. + + align:start position:0% +complicated plans. + + + align:start position:0% +complicated plans. +Um, see if I have that the Cuffner video + + align:start position:0% +Um, see if I have that the Cuffner video + + + align:start position:0% +Um, see if I have that the Cuffner video +there. + + align:start position:0% + + + + align:start position:0% + +Yeah, it's a animated GIF. So I should, + + align:start position:0% +Yeah, it's a animated GIF. So I should, + + + align:start position:0% +Yeah, it's a animated GIF. So I should, +you know, this is a this is H7 at the + + align:start position:0% +you know, this is a this is H7 at the + + + align:start position:0% +you know, this is a this is H7 at the +time. This was the um University of + + align:start position:0% +time. This was the um University of + + + align:start position:0% +time. This was the um University of +Tokyo humanoid entry before everybody + + align:start position:0% +Tokyo humanoid entry before everybody + + + align:start position:0% +Tokyo humanoid entry before everybody +started giving out ASMO. beforehand to + + align:start position:0% +started giving out ASMO. beforehand to + + + align:start position:0% +started giving out ASMO. beforehand to +start giving out asmos. This is + + align:start position:0% + + + + align:start position:0% + +um and it's doing things like taking + + align:start position:0% +um and it's doing things like taking + + + align:start position:0% +um and it's doing things like taking +that 32 degree of freedom robot, finding + + align:start position:0% +that 32 degree of freedom robot, finding + + + align:start position:0% +that 32 degree of freedom robot, finding +a plan to have it bend down and pick up + + align:start position:0% +a plan to have it bend down and pick up + + + align:start position:0% +a plan to have it bend down and pick up +a flashlight under the table, right? And + + align:start position:0% +a flashlight under the table, right? And + + + align:start position:0% +a flashlight under the table, right? And +that sort of that sort of shocked + + align:start position:0% +that sort of that sort of shocked + + + align:start position:0% +that sort of that sort of shocked +people. Okay. Now, people have gone off + + align:start position:0% +people. Okay. Now, people have gone off + + + align:start position:0% +people. Okay. Now, people have gone off +and used RTS to do things like protein + + align:start position:0% +and used RTS to do things like protein + + + align:start position:0% +and used RTS to do things like protein +folding. It's a pretty is a pretty hot + + align:start position:0% +folding. It's a pretty is a pretty hot + + + align:start position:0% +folding. It's a pretty is a pretty hot +topic in the motion planning community + + align:start position:0% +topic in the motion planning community + + + align:start position:0% +topic in the motion planning community +and these other very high complexity + + align:start position:0% +and these other very high complexity + + + align:start position:0% +and these other very high complexity +geometric algorithms, geometric planning + + align:start position:0% +geometric algorithms, geometric planning + + + align:start position:0% +geometric algorithms, geometric planning +problems that people just hadn't done + + align:start position:0% +problems that people just hadn't done + + + align:start position:0% +problems that people just hadn't done +before. Okay. But even this guy, even + + align:start position:0% +before. Okay. But even this guy, even + + + align:start position:0% +before. Okay. But even this guy, even +though it's a it's a robot, um his feet + + align:start position:0% +though it's a it's a robot, um his feet + + + align:start position:0% +though it's a it's a robot, um his feet +are flat on the ground. Yeah. And + + align:start position:0% +are flat on the ground. Yeah. And + + + align:start position:0% +are flat on the ground. Yeah. And +they're still just assuming that you can + + align:start position:0% +they're still just assuming that you can + + + align:start position:0% +they're still just assuming that you can +search in position space and then find + + align:start position:0% +search in position space and then find + + + align:start position:0% +search in position space and then find +some controller that'll stabilize it. So + + align:start position:0% +some controller that'll stabilize it. So + + + align:start position:0% +some controller that'll stabilize it. So +they're not doing the underactuated um + + align:start position:0% +they're not doing the underactuated um + + + align:start position:0% +they're not doing the underactuated um +planning + + align:start position:0% + + + + align:start position:0% + +example. All right. So I wouldn't be + + align:start position:0% +example. All right. So I wouldn't be + + + align:start position:0% +example. All right. So I wouldn't be +talking about it if I didn't think it + + align:start position:0% +talking about it if I didn't think it + + + align:start position:0% +talking about it if I didn't think it +was relevant for underactuated planning. + + align:start position:0% +was relevant for underactuated planning. + + + align:start position:0% +was relevant for underactuated planning. +So let's show you the + + align:start position:0% +So let's show you the + + + align:start position:0% +So let's show you the +um the basic story + + align:start position:0% + + + + align:start position:0% + +here. What happens if we do it on a + + align:start position:0% +here. What happens if we do it on a + + + align:start position:0% +here. What happens if we do it on a +simple pendulum? + + align:start position:0% + + + + align:start position:0% + +There we go. So you see I'm plotting + + align:start position:0% +There we go. So you see I'm plotting + + + align:start position:0% +There we go. So you see I'm plotting +only uh every 30 nodes or something like + + align:start position:0% +only uh every 30 nodes or something like + + + align:start position:0% +only uh every 30 nodes or something like +that. I pick a point at + + align:start position:0% + + + + align:start position:0% + +random. I start growing the tree. + + align:start position:0% +random. I start growing the tree. + + + align:start position:0% +random. I start growing the tree. +The way I grow the tree now is I don't + + align:start position:0% +The way I grow the tree now is I don't + + + align:start position:0% +The way I grow the tree now is I don't +go all the way towards the goal because + + align:start position:0% +go all the way towards the goal because + + + align:start position:0% +go all the way towards the goal because +I can't necessarily go all the way + + align:start position:0% +I can't necessarily go all the way + + + align:start position:0% +I can't necessarily go all the way +towards the goal. I just take a step in + + align:start position:0% +towards the goal. I just take a step in + + + align:start position:0% +towards the goal. I just take a step in +the direction of the + + align:start position:0% +the direction of the + + + align:start position:0% +the direction of the +goal. How do I take a step in the + + align:start position:0% +goal. How do I take a step in the + + + align:start position:0% +goal. How do I take a step in the +direction of the goal? I just try five + + align:start position:0% +direction of the goal? I just try five + + + align:start position:0% +direction of the goal? I just try five +random actions, let's say, and pick the + + align:start position:0% +random actions, let's say, and pick the + + + align:start position:0% +random actions, let's say, and pick the +one that got closest to the goal. So, if + + align:start position:0% +one that got closest to the goal. So, if + + + align:start position:0% +one that got closest to the goal. So, if +you look closely, every time it expands + + align:start position:0% +you look closely, every time it expands + + + align:start position:0% +you look closely, every time it expands +a node, you'll see a bunch of different + + align:start position:0% +a node, you'll see a bunch of different + + + align:start position:0% +a node, you'll see a bunch of different +arrows coming out and it picked out it + + align:start position:0% +arrows coming out and it picked out it + + + align:start position:0% +arrows coming out and it picked out it +picked the one that got closest to that + + align:start position:0% +picked the one that got closest to that + + + align:start position:0% +picked the one that got closest to that +s random sample point. Okay? And it's + + align:start position:0% +s random sample point. Okay? And it's + + + align:start position:0% +s random sample point. Okay? And it's +still just using the uklidian distance + + align:start position:0% +still just using the uklidian distance + + + align:start position:0% +still just using the uklidian distance +to try to um find its find the closest + + align:start position:0% + + + + align:start position:0% + +neighbor. This one's not I think I I + + align:start position:0% +neighbor. This one's not I think I I + + + align:start position:0% +neighbor. This one's not I think I I +didn't wasn't careful about doing the + + align:start position:0% +didn't wasn't careful about doing the + + + align:start position:0% +didn't wasn't careful about doing the +terminal condition, but I want you to to + + align:start position:0% +terminal condition, but I want you to to + + + align:start position:0% +terminal condition, but I want you to to +see what the most important thing about + + align:start position:0% +see what the most important thing about + + + align:start position:0% +see what the most important thing about +this is. What do you see in that + + align:start position:0% +this is. What do you see in that + + + align:start position:0% +this is. What do you see in that +plot besides a mess as it gets adding + + align:start position:0% +plot besides a mess as it gets adding + + + align:start position:0% +plot besides a mess as it gets adding +more and + + align:start position:0% + + + + align:start position:0% + +more? What I see is I see the + + align:start position:0% +more? What I see is I see the + + + align:start position:0% +more? What I see is I see the +fundamental structure of the pendulum. + + align:start position:0% +fundamental structure of the pendulum. + + + align:start position:0% +fundamental structure of the pendulum. +Yeah. I see these spiral trajectories, + + align:start position:0% +Yeah. I see these spiral trajectories, + + + align:start position:0% +Yeah. I see these spiral trajectories, +right? It's amazing to me + + align:start position:0% +right? It's amazing to me + + + align:start position:0% +right? It's amazing to me +that trivial random randomized + + align:start position:0% +that trivial random randomized + + + align:start position:0% +that trivial random randomized +algorithms like this can probe the basic + + align:start position:0% +algorithms like this can probe the basic + + + align:start position:0% +algorithms like this can probe the basic +dynamics of my underactuated system. + + align:start position:0% +dynamics of my underactuated system. + + + align:start position:0% +dynamics of my underactuated system. +Yeah. + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +Right? So if you + + align:start position:0% +Right? So if you + + + align:start position:0% +Right? So if you +see the algorithm is + + align:start position:0% +see the algorithm is + + + align:start position:0% +see the algorithm is +now very simple, right? So I pick a + + align:start position:0% +now very simple, right? So I pick a + + + align:start position:0% +now very simple, right? So I pick a +point at random. That's actually a good + + align:start position:0% +point at random. That's actually a good + + + align:start position:0% +point at random. That's actually a good +example I just happened upon. + + align:start position:0% + + + + align:start position:0% + +Right? Pick a point at random. The blue, + + align:start position:0% +Right? Pick a point at random. The blue, + + + align:start position:0% +Right? Pick a point at random. The blue, +the red is my random sample point. The + + align:start position:0% +the red is my random sample point. The + + + align:start position:0% +the red is my random sample point. The +blue is the closest point in the tree in + + align:start position:0% +blue is the closest point in the tree in + + + align:start position:0% +blue is the closest point in the tree in +the uklidian sense. it happens to be a + + align:start position:0% +the uklidian sense. it happens to be a + + + align:start position:0% +the uklidian sense. it happens to be a +horrible choice for the closest point uh + + align:start position:0% +horrible choice for the closest point uh + + + align:start position:0% +horrible choice for the closest point uh +on the tree in the dynamic sense because + + align:start position:0% +on the tree in the dynamic sense because + + + align:start position:0% +on the tree in the dynamic sense because +I know in state space my dynamics can + + align:start position:0% +I know in state space my dynamics can + + + align:start position:0% +I know in state space my dynamics can +only go that way, right? So really uh + + align:start position:0% +only go that way, right? So really uh + + + align:start position:0% +only go that way, right? So really uh +I'd like to have picked up a point back + + align:start position:0% +I'd like to have picked up a point back + + + align:start position:0% +I'd like to have picked up a point back +there that was farther in uklidian + + align:start position:0% +there that was farther in uklidian + + + align:start position:0% +there that was farther in uklidian +distance but closer sort of in dynamic + + align:start position:0% +distance but closer sort of in dynamic + + + align:start position:0% +distance but closer sort of in dynamic +distance and I'll actually talk more + + align:start position:0% +distance and I'll actually talk more + + + align:start position:0% +distance and I'll actually talk more +next lecture about how you could do + + align:start position:0% +next lecture about how you could do + + + align:start position:0% +next lecture about how you could do +that. Okay. But from that node, I try 10 + + align:start position:0% +that. Okay. But from that node, I try 10 + + + align:start position:0% +that. Okay. But from that node, I try 10 +different actions, see where it would + + align:start position:0% +different actions, see where it would + + + align:start position:0% +different actions, see where it would +have taken me, and pick the one that + + align:start position:0% +have taken me, and pick the one that + + + align:start position:0% +have taken me, and pick the one that +ended up closest in uklidian distance, + + align:start position:0% +ended up closest in uklidian distance, + + + align:start position:0% +ended up closest in uklidian distance, +which happens to have been the one that + + align:start position:0% +which happens to have been the one that + + + align:start position:0% +which happens to have been the one that +happened + + align:start position:0% +happened + + + align:start position:0% +happened +horizontally. That's enough to let this + + align:start position:0% +horizontally. That's enough to let this + + + align:start position:0% +horizontally. That's enough to let this +thing just sort of spread itself out + + align:start position:0% +thing just sort of spread itself out + + + align:start position:0% +thing just sort of spread itself out +into the world like a like a disease or + + align:start position:0% +into the world like a like a disease or + + + align:start position:0% +into the world like a like a disease or +something, right? Going just covering + + align:start position:0% +something, right? Going just covering + + + align:start position:0% +something, right? Going just covering +the the space a and probing the dynamics + + align:start position:0% +the the space a and probing the dynamics + + + align:start position:0% +the the space a and probing the dynamics +of the system. And you wait until you + + align:start position:0% +of the system. And you wait until you + + + align:start position:0% +of the system. And you wait until you +get close to the + + align:start position:0% +get close to the + + + align:start position:0% +get close to the +goal. Mhm. + + align:start position:0% + + + + align:start position:0% + +RTS are a very very powerful way now to + + align:start position:0% +RTS are a very very powerful way now to + + + align:start position:0% +RTS are a very very powerful way now to +to start um trying to find reasonable + + align:start position:0% +to start um trying to find reasonable + + + align:start position:0% +to start um trying to find reasonable +plans uh on a + + align:start position:0% +plans uh on a + + + align:start position:0% +plans uh on a +robot. That's the vanilla RT algorithm. + + align:start position:0% +robot. That's the vanilla RT algorithm. + + + align:start position:0% +robot. That's the vanilla RT algorithm. +There's a lot of ways you can quickly + + align:start position:0% +There's a lot of ways you can quickly + + + align:start position:0% +There's a lot of ways you can quickly +improve them. Okay? And actually any of + + align:start position:0% +improve them. Okay? And actually any of + + + align:start position:0% +improve them. Okay? And actually any of +the the graph-based search algorithms + + align:start position:0% +the the graph-based search algorithms + + + align:start position:0% +the the graph-based search algorithms +um do this. + + align:start position:0% +um do this. + + + align:start position:0% +um do this. +So if I wanted to to u do some simple + + align:start position:0% +So if I wanted to to u do some simple + + + align:start position:0% +So if I wanted to to u do some simple +things to try to speed up that + + align:start position:0% +things to try to speed up that + + + align:start position:0% +things to try to speed up that +algorithm, what might you + + align:start position:0% + + + + align:start position:0% + +suggest? The only real reason it felt + + align:start position:0% +suggest? The only real reason it felt + + + align:start position:0% +suggest? The only real reason it felt +there's a couple reasons why it felt + + align:start position:0% +there's a couple reasons why it felt + + + align:start position:0% +there's a couple reasons why it felt +inefficient. One of them is because it's + + align:start position:0% +inefficient. One of them is because it's + + + align:start position:0% +inefficient. One of them is because it's +it's not doing a very nice job of of + + align:start position:0% +it's not doing a very nice job of of + + + align:start position:0% +it's not doing a very nice job of of +chasing these sort of intermediate + + align:start position:0% +chasing these sort of intermediate + + + align:start position:0% +chasing these sort of intermediate +goals, right? It's like like that + + align:start position:0% +goals, right? It's like like that + + + align:start position:0% +goals, right? It's like like that +example showed. The other thing is it it + + align:start position:0% +example showed. The other thing is it it + + + align:start position:0% +example showed. The other thing is it it +seems like it's not really making any + + align:start position:0% +seems like it's not really making any + + + align:start position:0% +seems like it's not really making any +effort to go towards the goal. + + align:start position:0% +effort to go towards the goal. + + + align:start position:0% +effort to go towards the goal. +Okay, so there's a handful of huristics + + align:start position:0% +Okay, so there's a handful of huristics + + + align:start position:0% +Okay, so there's a handful of huristics +that people use to make these things + + align:start position:0% +that people use to make these things + + + align:start position:0% +that people use to make these things +tick. Okay. + + align:start position:0% + + + + align:start position:0% + +Um, one of them is a goal bias. + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +Okay. If um the way the go I mean + + align:start position:0% +Okay. If um the way the go I mean + + + align:start position:0% +Okay. If um the way the go I mean +there's lots of ways to implement it. + + align:start position:0% +there's lots of ways to implement it. + + + align:start position:0% +there's lots of ways to implement it. +The standard way to implement it is um + + align:start position:0% +The standard way to implement it is um + + + align:start position:0% +The standard way to implement it is um +with let's say + + align:start position:0% +with let's say + + + align:start position:0% +with let's say +um probability + + align:start position:0% +um probability + + + align:start position:0% +um probability +um uh 0.5 or something like that 0.05 5. + + align:start position:0% +um uh 0.5 or something like that 0.05 5. + + + align:start position:0% +um uh 0.5 or something like that 0.05 5. +Um, choose my random sample to be the + + align:start position:0% + + + + align:start position:0% + +goal. + + align:start position:0% + + + + align:start position:0% + +Otherwise, my random sample is just the + + align:start position:0% +Otherwise, my random sample is just the + + + align:start position:0% +Otherwise, my random sample is just the +uniform + + align:start position:0% + + + + align:start position:0% + +distribution. Okay. + + align:start position:0% +distribution. Okay. + + + align:start position:0% +distribution. Okay. +That would certainly encourage the + + align:start position:0% +That would certainly encourage the + + + align:start position:0% +That would certainly encourage the +system to find its way to the goal a lot + + align:start position:0% +system to find its way to the goal a lot + + + align:start position:0% +system to find its way to the goal a lot +more + + align:start position:0% +more + + + align:start position:0% +more +efficiently. What's + + align:start position:0% +efficiently. What's + + + align:start position:0% +efficiently. What's +another what's another possible way to + + align:start position:0% +another what's another possible way to + + + align:start position:0% +another what's another possible way to +speed this up? + + align:start position:0% +speed this up? + + + align:start position:0% +speed this up? +Birectional. Yeah. In fact, all of the + + align:start position:0% +Birectional. Yeah. In fact, all of the + + + align:start position:0% +Birectional. Yeah. In fact, all of the +search techniques, the breadth first, + + align:start position:0% +search techniques, the breadth first, + + + align:start position:0% +search techniques, the breadth first, +depth first, AAR on discrete graph + + align:start position:0% +depth first, AAR on discrete graph + + + align:start position:0% +depth first, AAR on discrete graph +searches, a lot of time, one of the + + align:start position:0% +searches, a lot of time, one of the + + + align:start position:0% +searches, a lot of time, one of the +standard things people do is they'll do + + align:start position:0% +standard things people do is they'll do + + + align:start position:0% +standard things people do is they'll do +a backwards search, right? + + align:start position:0% +a backwards search, right? + + + align:start position:0% +a backwards search, right? +start while you're growing out from the + + align:start position:0% +start while you're growing out from the + + + align:start position:0% +start while you're growing out from the +start to the towards the goal, might as + + align:start position:0% +start to the towards the goal, might as + + + align:start position:0% +start to the towards the goal, might as +well start from the goal and go + + align:start position:0% +well start from the goal and go + + + align:start position:0% +well start from the goal and go +backwards. Um, it feels a lot less like + + align:start position:0% +backwards. Um, it feels a lot less like + + + align:start position:0% +backwards. Um, it feels a lot less like +this. The problem with this is it feels + + align:start position:0% +this. The problem with this is it feels + + + align:start position:0% +this. The problem with this is it feels +like you're trying to find a needle in a + + align:start position:0% +like you're trying to find a needle in a + + + align:start position:0% +like you're trying to find a needle in a +hay stack, right? If you can grow a tree + + align:start position:0% +hay stack, right? If you can grow a tree + + + align:start position:0% +hay stack, right? If you can grow a tree +in both directions, then at least you + + align:start position:0% +in both directions, then at least you + + + align:start position:0% +in both directions, then at least you +got a lot of needles to look for. Yeah. + + align:start position:0% +got a lot of needles to look for. Yeah. + + + align:start position:0% +got a lot of needles to look for. Yeah. +And you just wait till the the trees + + align:start position:0% +And you just wait till the the trees + + + align:start position:0% +And you just wait till the the trees +come um fairly + + align:start position:0% + + + + align:start position:0% + +close and even backward search sometimes + + align:start position:0% +close and even backward search sometimes + + + align:start position:0% +close and even backward search sometimes +by itself can be faster. It depends on + + align:start position:0% +by itself can be faster. It depends on + + + align:start position:0% +by itself can be faster. It depends on +the system. + + align:start position:0% + + + + align:start position:0% + +Is that because like you if your goal is + + align:start position:0% +Is that because like you if your goal is + + + align:start position:0% +Is that because like you if your goal is +an unstable point the backward search is + + align:start position:0% +an unstable point the backward search is + + + align:start position:0% +an unstable point the backward search is +more likely to find that like + + align:start position:0% +more likely to find that like + + + align:start position:0% +more likely to find that like +intuitively what why sometimes a + + align:start position:0% +intuitively what why sometimes a + + + align:start position:0% +intuitively what why sometimes a +backwards search would look work better + + align:start position:0% +backwards search would look work better + + + align:start position:0% +backwards search would look work better +in cases like under + + align:start position:0% +in cases like under + + + align:start position:0% +in cases like under +it's a really good question because it + + align:start position:0% +it's a really good question because it + + + align:start position:0% +it's a really good question because it +you might have trouble going to some + + align:start position:0% +you might have trouble going to some + + + align:start position:0% +you might have trouble going to some +type of fix points but the backward + + align:start position:0% +type of fix points but the backward + + + align:start position:0% +type of fix points but the backward +search already starts you off + + align:start position:0% + + + + align:start position:0% + +there. I I will I won't I won't put my + + align:start position:0% +there. I I will I won't I won't put my + + + align:start position:0% +there. I I will I won't I won't put my +weight behind it, but that that sounds + + align:start position:0% +weight behind it, but that that sounds + + + align:start position:0% +weight behind it, but that that sounds +like a pretty good explanation. Yeah, + + align:start position:0% +like a pretty good explanation. Yeah, + + + align:start position:0% +like a pretty good explanation. Yeah, +in practice we always do birectional + + align:start position:0% +in practice we always do birectional + + + align:start position:0% +in practice we always do birectional +trees, right? You always want to do + + align:start position:0% +trees, right? You always want to do + + + align:start position:0% +trees, right? You always want to do +both, right? Yeah. You'd never just go + + align:start position:0% +both, right? Yeah. You'd never just go + + + align:start position:0% +both, right? Yeah. You'd never just go +back. Yeah. But certainly in the + + align:start position:0% +back. Yeah. But certainly in the + + + align:start position:0% +back. Yeah. But certainly in the +kinematic case, you could definitely + + align:start position:0% +kinematic case, you could definitely + + + align:start position:0% +kinematic case, you could definitely +exam imagine cases where the backwards + + align:start position:0% +exam imagine cases where the backwards + + + align:start position:0% +exam imagine cases where the backwards +would could be faster. Let's say it's + + align:start position:0% +would could be faster. Let's say it's + + + align:start position:0% +would could be faster. Let's say it's +it's hiding in some little uh island, + + align:start position:0% +it's hiding in some little uh island, + + + align:start position:0% +it's hiding in some little uh island, +right? And you just want to get out and + + align:start position:0% +right? And you just want to get out and + + + align:start position:0% +right? And you just want to get out and +that much easier than finding your way + + align:start position:0% +that much easier than finding your way + + + align:start position:0% +that much easier than finding your way +into the island, let's say. Um the the + + align:start position:0% +into the island, let's say. Um the the + + + align:start position:0% +into the island, let's say. Um the the +instability. So certainly we've we've + + align:start position:0% +instability. So certainly we've we've + + + align:start position:0% +instability. So certainly we've we've +noticed um uh sensitivities to growing + + align:start position:0% +noticed um uh sensitivities to growing + + + align:start position:0% +noticed um uh sensitivities to growing +RTS around stable on very unstable fixed + + align:start position:0% +RTS around stable on very unstable fixed + + + align:start position:0% +RTS around stable on very unstable fixed +points. Um and it might be it might be + + align:start position:0% +points. Um and it might be it might be + + + align:start position:0% +points. Um and it might be it might be +exactly what you said. It might be. + + align:start position:0% +exactly what you said. It might be. + + + align:start position:0% +exactly what you said. It might be. +Yeah. + + align:start position:0% +Yeah. + + + align:start position:0% +Yeah. +Um is the uklidian norm the best metric + + align:start position:0% +Um is the uklidian norm the best metric + + + align:start position:0% +Um is the uklidian norm the best metric +for this? Good. The uklidian norm is a + + align:start position:0% +for this? Good. The uklidian norm is a + + + align:start position:0% +for this? Good. The uklidian norm is a +horrible metric for this. Okay. + + align:start position:0% + + + + align:start position:0% + +What do you think would be a better + + align:start position:0% +What do you think would be a better + + + align:start position:0% +What do you think would be a better +metric? + + align:start position:0% + + + + align:start position:0% + +Awesome. So, energy is a good + + align:start position:0% +Awesome. So, energy is a good + + + align:start position:0% +Awesome. So, energy is a good +candidate. In fact, I think depending on + + align:start position:0% +candidate. In fact, I think depending on + + + align:start position:0% +candidate. In fact, I think depending on +what we put on the problem set, we might + + align:start position:0% +what we put on the problem set, we might + + + align:start position:0% +what we put on the problem set, we might +ask you to to try an energy metric. um + + align:start position:0% +ask you to to try an energy metric. um + + + align:start position:0% +ask you to to try an energy metric. um +to do it. Um so almost everybody says + + align:start position:0% +to do it. Um so almost everybody says + + + align:start position:0% +to do it. Um so almost everybody says +this would work better with a better + + align:start position:0% +this would work better with a better + + + align:start position:0% +this would work better with a better +distance + + align:start position:0% +distance + + + align:start position:0% +distance +metric and almost nobody can tell you a + + align:start position:0% +metric and almost nobody can tell you a + + + align:start position:0% +metric and almost nobody can tell you a +better distance metric for these kind of + + align:start position:0% +better distance metric for these kind of + + + align:start position:0% +better distance metric for these kind of +systems. + + align:start position:0% +systems. + + + align:start position:0% +systems. +Okay. So + + align:start position:0% +Okay. So + + + align:start position:0% +Okay. So +uh we actually have a couple ideas uh + + align:start position:0% +uh we actually have a couple ideas uh + + + align:start position:0% +uh we actually have a couple ideas uh +that we've been working on in in lab. + + align:start position:0% +that we've been working on in in lab. + + + align:start position:0% +that we've been working on in in lab. +Elena has been uh been working on some + + align:start position:0% +Elena has been uh been working on some + + + align:start position:0% +Elena has been uh been working on some +LQR based distance metrics for instance. + + align:start position:0% +LQR based distance metrics for instance. + + + align:start position:0% +LQR based distance metrics for instance. +Okay. So what you what did you just say? + + align:start position:0% +Okay. So what you what did you just say? + + + align:start position:0% +Okay. So what you what did you just say? +You said um time to arrival. How would + + align:start position:0% +You said um time to arrival. How would + + + align:start position:0% +You said um time to arrival. How would +you compute a time to arrival? Yes. Do + + align:start position:0% +you compute a time to arrival? Yes. Do + + + align:start position:0% +you compute a time to arrival? Yes. Do +you like a million time, right? + + align:start position:0% +you like a million time, right? + + + align:start position:0% +you like a million time, right? +Exactly. + + align:start position:0% +Exactly. + + + align:start position:0% +Exactly. +So, you just guessed the one that's + + align:start position:0% +So, you just guessed the one that's + + + align:start position:0% +So, you just guessed the one that's +that's one of my favorites right now, + + align:start position:0% +that's one of my favorites right now, + + + align:start position:0% +that's one of my favorites right now, +right? switches. So, um, one idea + + align:start position:0% +right? switches. So, um, one idea + + + align:start position:0% +right? switches. So, um, one idea +here, not fully proven yet, but it's + + align:start position:0% +here, not fully proven yet, but it's + + + align:start position:0% +here, not fully proven yet, but it's +still in the oven here, is that + + align:start position:0% +still in the oven here, is that + + + align:start position:0% +still in the oven here, is that +um, that every time I pick a random + + align:start position:0% +um, that every time I pick a random + + + align:start position:0% +um, that every time I pick a random +sample point, yeah, I'll linearize a + + align:start position:0% +sample point, yeah, I'll linearize a + + + align:start position:0% +sample point, yeah, I'll linearize a +system around that point, let's say + + align:start position:0% +system around that point, let's say + + + align:start position:0% +system around that point, let's say +that's a cartoon of a linearization, + + align:start position:0% +that's a cartoon of a linearization, + + + align:start position:0% +that's a cartoon of a linearization, +yeah, compute a uh, LQR stabilizer + + align:start position:0% +yeah, compute a uh, LQR stabilizer + + + align:start position:0% +yeah, compute a uh, LQR stabilizer +around + + align:start position:0% +around + + + align:start position:0% +around +this and then use the value function for + + align:start position:0% +this and then use the value function for + + + align:start position:0% +this and then use the value function for +a minimum time problem. Yeah. So, so + + align:start position:0% +a minimum time problem. Yeah. So, so + + + align:start position:0% +a minimum time problem. Yeah. So, so +comput a + + align:start position:0% +comput a + + + align:start position:0% +comput a +um min time LQR + + align:start position:0% +um min time LQR + + + align:start position:0% +um min time LQR +actually around this point and then use + + align:start position:0% +actually around this point and then use + + + align:start position:0% +actually around this point and then use +the value function as a distance + + align:start position:0% +the value function as a distance + + + align:start position:0% +the value function as a distance +metric. The + + align:start position:0% + + + + align:start position:0% + +the Okay. So, I like that idea a lot. + + align:start position:0% +the Okay. So, I like that idea a lot. + + + align:start position:0% +the Okay. So, I like that idea a lot. +Yeah. There's a couple subtleties that + + align:start position:0% +Yeah. There's a couple subtleties that + + + align:start position:0% +Yeah. There's a couple subtleties that +go into it. So when you pick a random + + align:start position:0% +go into it. So when you pick a random + + + align:start position:0% +go into it. So when you pick a random +point in state space, if it's got a + + align:start position:0% +point in state space, if it's got a + + + align:start position:0% +point in state space, if it's got a +velocity or you know most points you + + align:start position:0% +velocity or you know most points you + + + align:start position:0% +velocity or you know most points you +pick randomly in state space are not + + align:start position:0% +pick randomly in state space are not + + + align:start position:0% +pick randomly in state space are not +stabilizable. So you can't do an + + align:start position:0% +stabilizable. So you can't do an + + + align:start position:0% +stabilizable. So you can't do an +infinite horizon minimum time LQR. You + + align:start position:0% +infinite horizon minimum time LQR. You + + + align:start position:0% +infinite horizon minimum time LQR. You +have to do a finite horizon and then + + align:start position:0% +have to do a finite horizon and then + + + align:start position:0% +have to do a finite horizon and then +potentially search over horizon times. + + align:start position:0% +potentially search over horizon times. + + + align:start position:0% +potentially search over horizon times. +But you can do that actually pretty + + align:start position:0% +But you can do that actually pretty + + + align:start position:0% +But you can do that actually pretty +pretty + + align:start position:0% +pretty + + + align:start position:0% +pretty +efficiently. The other issue about it is + + align:start position:0% +efficiently. The other issue about it is + + + align:start position:0% +efficiently. The other issue about it is +that it's actually not a proper distance + + align:start position:0% +that it's actually not a proper distance + + + align:start position:0% +that it's actually not a proper distance +metric. + + align:start position:0% + + + + align:start position:0% + +Um, why is it not a proper distance + + align:start position:0% +Um, why is it not a proper distance + + + align:start position:0% +Um, why is it not a proper distance +metric? Anybody? It doesn't follow the + + align:start position:0% +metric? Anybody? It doesn't follow the + + + align:start position:0% +metric? Anybody? It doesn't follow the +So, I think + + align:start position:0% + + + + align:start position:0% + +it probably doesn't follow the triangle + + align:start position:0% +it probably doesn't follow the triangle + + + align:start position:0% +it probably doesn't follow the triangle +inequality. It certainly does. It + + align:start position:0% +inequality. It certainly does. It + + + align:start position:0% +inequality. It certainly does. It +doesn't even have symmetry, right? + + align:start position:0% +doesn't even have symmetry, right? + + + align:start position:0% +doesn't even have symmetry, right? +If I were to linearize around this point + + align:start position:0% +If I were to linearize around this point + + + align:start position:0% +If I were to linearize around this point +and comput its distance, linearize + + align:start position:0% +and comput its distance, linearize + + + align:start position:0% +and comput its distance, linearize +around this point, there's absolutely no + + align:start position:0% +around this point, there's absolutely no + + + align:start position:0% +around this point, there's absolutely no +guarantees that it would be the same. + + align:start position:0% +guarantees that it would be the same. + + + align:start position:0% +guarantees that it would be the same. +Um, but I don't care about that + + align:start position:0% +Um, but I don't care about that + + + align:start position:0% +Um, but I don't care about that +actually. I just have to put it in the + + align:start position:0% + + + + align:start position:0% + +paper. Yeah. As long as it works, + + align:start position:0% + + + + align:start position:0% + +right? Okay. + + align:start position:0% +right? Okay. + + + align:start position:0% +right? Okay. +Um, it's also more expensive a little + + align:start position:0% +Um, it's also more expensive a little + + + align:start position:0% +Um, it's also more expensive a little +bit, but it can make a dramatic + + align:start position:0% +bit, but it can make a dramatic + + + align:start position:0% +bit, but it can make a dramatic +improvement in in the way it uh um it it + + align:start position:0% +improvement in in the way it uh um it it + + + align:start position:0% +improvement in in the way it uh um it it +spreads. There's another idea. I was + + align:start position:0% +spreads. There's another idea. I was + + + align:start position:0% +spreads. There's another idea. I was +actually planning to not to talk about + + align:start position:0% +actually planning to not to talk about + + + align:start position:0% +actually planning to not to talk about +some of the the more subtle ideas um uh + + align:start position:0% +some of the the more subtle ideas um uh + + + align:start position:0% +some of the the more subtle ideas um uh +next time, but why since we're at it, + + align:start position:0% +next time, but why since we're at it, + + + align:start position:0% +next time, but why since we're at it, +the other way to do it is to change um + + align:start position:0% +the other way to do it is to change um + + + align:start position:0% +the other way to do it is to change um +the sampling distribution. + + align:start position:0% + + + + align:start position:0% + +So, Alec Skull in our group has got um a + + align:start position:0% +So, Alec Skull in our group has got um a + + + align:start position:0% +So, Alec Skull in our group has got um a +very clever way to uh to grow these + + align:start position:0% +very clever way to uh to grow these + + + align:start position:0% +very clever way to uh to grow these +trees. + + align:start position:0% +trees. + + + align:start position:0% +trees. +Um where it uses um a sampling metric + + align:start position:0% +Um where it uses um a sampling metric + + + align:start position:0% +Um where it uses um a sampling metric +that doesn't try to to go where it can't + + align:start position:0% +that doesn't try to to go where it can't + + + align:start position:0% +that doesn't try to to go where it can't +go. Let me just see if I can say that + + align:start position:0% +go. Let me just see if I can say that + + + align:start position:0% +go. Let me just see if I can say that +more carefully + + align:start position:0% + + + + align:start position:0% + +since I told DARPA about it 3 days ago. + + align:start position:0% +since I told DARPA about it 3 days ago. + + + align:start position:0% +since I told DARPA about it 3 days ago. +So, might as well show you the picture. + + align:start position:0% + + + + align:start position:0% + +Okay. So, um, this is Alex's, uh, + + align:start position:0% +Okay. So, um, this is Alex's, uh, + + + align:start position:0% +Okay. So, um, this is Alex's, uh, +algorithm for, + + align:start position:0% +algorithm for, + + + align:start position:0% +algorithm for, +uh, being more clever at expanding. Uh, + + align:start position:0% +uh, being more clever at expanding. Uh, + + + align:start position:0% +uh, being more clever at expanding. Uh, +he changes the bias to the point where + + align:start position:0% +he changes the bias to the point where + + + align:start position:0% +he changes the bias to the point where +this is the tree we just saw, right? + + align:start position:0% +this is the tree we just saw, right? + + + align:start position:0% +this is the tree we just saw, right? +Basically, right? Um, and his new tree + + align:start position:0% +Basically, right? Um, and his new tree + + + align:start position:0% +Basically, right? Um, and his new tree +looks like that. So, that looks pretty + + align:start position:0% +looks like that. So, that looks pretty + + + align:start position:0% +looks like that. So, that looks pretty +compelling. Yeah. How did he do it? + + align:start position:0% +compelling. Yeah. How did he do it? + + + align:start position:0% +compelling. Yeah. How did he do it? +Um, he does this thing. Um, he calls + + align:start position:0% +Um, he does this thing. Um, he calls + + + align:start position:0% +Um, he does this thing. Um, he calls +reachability guided RRTs. Okay. Every + + align:start position:0% +reachability guided RRTs. Okay. Every + + + align:start position:0% +reachability guided RRTs. Okay. Every +time he uh expands a node, he also + + align:start position:0% +time he uh expands a node, he also + + + align:start position:0% +time he uh expands a node, he also +expands what what would happen if I had + + align:start position:0% +expands what what would happen if I had + + + align:start position:0% +expands what what would happen if I had +applied maximum torque and minimum + + align:start position:0% +applied maximum torque and minimum + + + align:start position:0% +applied maximum torque and minimum +torque. Okay, so he expands a couple + + align:start position:0% +torque. Okay, so he expands a couple + + + align:start position:0% +torque. Okay, so he expands a couple +nodes that that represent a cone of + + align:start position:0% + + + + align:start position:0% + +feasibility. The algorithm turns out to + + align:start position:0% +feasibility. The algorithm turns out to + + + align:start position:0% +feasibility. The algorithm turns out to +be trivial. Okay, so so now I take my + + align:start position:0% +be trivial. Okay, so so now I take my + + + align:start position:0% +be trivial. Okay, so so now I take my +uklidian distance metric or whatever it + + align:start position:0% +uklidian distance metric or whatever it + + + align:start position:0% +uklidian distance metric or whatever it +is, um pick my random sample point. If + + align:start position:0% +is, um pick my random sample point. If + + + align:start position:0% +is, um pick my random sample point. If +the closest point is one of these + + align:start position:0% +the closest point is one of these + + + align:start position:0% +the closest point is one of these +boundary feasible things, then that + + align:start position:0% +boundary feasible things, then that + + + align:start position:0% +boundary feasible things, then that +means there's room to grow the + + align:start position:0% +means there's room to grow the + + + align:start position:0% +means there's room to grow the +tree. If the closest point, however, is + + align:start position:0% +tree. If the closest point, however, is + + + align:start position:0% +tree. If the closest point, however, is +one of the nodes on my actual graph, + + align:start position:0% +one of the nodes on my actual graph, + + + align:start position:0% +one of the nodes on my actual graph, +that means I'm already there's I'm not + + align:start position:0% +that means I'm already there's I'm not + + + align:start position:0% +that means I'm already there's I'm not +feasible. I said that quickly, but long + + align:start position:0% +feasible. I said that quickly, but long + + + align:start position:0% +feasible. I said that quickly, but long +story short, there's a trivial check + + align:start position:0% +story short, there's a trivial check + + + align:start position:0% +story short, there's a trivial check +here which changes your s effectively + + align:start position:0% +here which changes your s effectively + + + align:start position:0% +here which changes your s effectively +changes your sampling distribution just + + align:start position:0% +changes your sampling distribution just + + + align:start position:0% +changes your sampling distribution just +by saying sample a point. If the closest + + align:start position:0% +by saying sample a point. If the closest + + + align:start position:0% +by saying sample a point. If the closest +point on there is not one of my boundary + + align:start position:0% +point on there is not one of my boundary + + + align:start position:0% +point on there is not one of my boundary +regions, but one of my normal tree + + align:start position:0% +regions, but one of my normal tree + + + align:start position:0% +regions, but one of my normal tree +elements, then I know I can't grow + + align:start position:0% +elements, then I know I can't grow + + + align:start position:0% +elements, then I know I can't grow +there. Okay? And if I get that, I just + + align:start position:0% +there. Okay? And if I get that, I just + + + align:start position:0% +there. Okay? And if I get that, I just +throw that point away. Pick another + + align:start position:0% +throw that point away. Pick another + + + align:start position:0% +throw that point away. Pick another +point. What that does is it effectively + + align:start position:0% +point. What that does is it effectively + + + align:start position:0% +point. What that does is it effectively +changes the sampling distribution to be + + align:start position:0% +changes the sampling distribution to be + + + align:start position:0% +changes the sampling distribution to be +the green region. it just throws out all + + align:start position:0% +the green region. it just throws out all + + + align:start position:0% +the green region. it just throws out all +these unnecessary points that you can't + + align:start position:0% +these unnecessary points that you can't + + + align:start position:0% +these unnecessary points that you can't +get towards and changes your sampling + + align:start position:0% +get towards and changes your sampling + + + align:start position:0% +get towards and changes your sampling +distribution. So, it's only trying to + + align:start position:0% +distribution. So, it's only trying to + + + align:start position:0% +distribution. So, it's only trying to +grow in places that it can actually go + + align:start position:0% +grow in places that it can actually go + + + align:start position:0% +grow in places that it can actually go +to where the trees got a a chance of + + align:start position:0% +to where the trees got a a chance of + + + align:start position:0% +to where the trees got a a chance of +growing towards. Okay. So, I think the + + align:start position:0% +growing towards. Okay. So, I think the + + + align:start position:0% +growing towards. Okay. So, I think the +the the world is still sort of small + + align:start position:0% +the the world is still sort of small + + + align:start position:0% +the the world is still sort of small +enough that people are still finding + + align:start position:0% +enough that people are still finding + + + align:start position:0% +enough that people are still finding +pretty clever little tricks to the RTS + + align:start position:0% +pretty clever little tricks to the RTS + + + align:start position:0% +pretty clever little tricks to the RTS +that make them grow a lot better in + + align:start position:0% +that make them grow a lot better in + + + align:start position:0% +that make them grow a lot better in +constrained systems like + + align:start position:0% +constrained systems like + + + align:start position:0% +constrained systems like +this. Okay. Okay, so that's happens to + + align:start position:0% +this. Okay. Okay, so that's happens to + + + align:start position:0% +this. Okay. Okay, so that's happens to +be I think a very good one for um for + + align:start position:0% +be I think a very good one for um for + + + align:start position:0% +be I think a very good one for um for +our kind of + + align:start position:0% + + + + align:start position:0% + +problems. But it also points out what + + align:start position:0% +problems. But it also points out what + + + align:start position:0% +problems. But it also points out what +RTS are bad at, + + align:start position:0% +RTS are bad at, + + + align:start position:0% +RTS are bad at, +right? So + + align:start position:0% +right? So + + + align:start position:0% +right? So +um so what kind of problems would you + + align:start position:0% +um so what kind of problems would you + + + align:start position:0% +um so what kind of problems would you +expect an RT to work on and what would + + align:start position:0% +expect an RT to work on and what would + + + align:start position:0% +expect an RT to work on and what would +you not expect an RT to work on? + + align:start position:0% + + + + align:start position:0% + +The classic case of something you + + align:start position:0% +The classic case of something you + + + align:start position:0% +The classic case of something you +shouldn't expect an RT to do very well + + align:start position:0% +shouldn't expect an RT to do very well + + + align:start position:0% +shouldn't expect an RT to do very well +on is something uh that looks like this. + + align:start position:0% +on is something uh that looks like this. + + + align:start position:0% +on is something uh that looks like this. +Let's say uh X start is over here, X + + align:start position:0% +Let's say uh X start is over here, X + + + align:start position:0% +Let's say uh X start is over here, X +goal is over + + align:start position:0% +goal is over + + + align:start position:0% +goal is over +[Music] + + align:start position:0% + + + + align:start position:0% + +here and my obstacles look like + + align:start position:0% +here and my obstacles look like + + + align:start position:0% +here and my obstacles look like +this. Right? + + align:start position:0% +this. Right? + + + align:start position:0% +this. Right? +In general, I think + + align:start position:0% +In general, I think + + + align:start position:0% +In general, I think +uh it's fair to say RRTs don't + + align:start position:0% +uh it's fair to say RRTs don't + + + align:start position:0% +uh it's fair to say RRTs don't +like tunnels and + + align:start position:0% + + + + align:start position:0% + +tubes, right? What's going to happen if + + align:start position:0% +tubes, right? What's going to happen if + + + align:start position:0% +tubes, right? What's going to happen if +I run my RRT on this sort of a system? + + align:start position:0% +I run my RRT on this sort of a system? + + + align:start position:0% +I run my RRT on this sort of a system? +All right, so I I pick, you know, I got + + align:start position:0% +All right, so I I pick, you know, I got + + + align:start position:0% +All right, so I I pick, you know, I got +my tree here. Pick a point here. Fine. + + align:start position:0% +my tree here. Pick a point here. Fine. + + + align:start position:0% +my tree here. Pick a point here. Fine. +Pick a point here. I'll quickly cover + + align:start position:0% +Pick a point here. I'll quickly cover + + + align:start position:0% +Pick a point here. I'll quickly cover +this area. Pick a point here. I throw it + + align:start position:0% +this area. Pick a point here. I throw it + + + align:start position:0% +this area. Pick a point here. I throw it +away. Pick a point through here. Throw + + align:start position:0% +away. Pick a point through here. Throw + + + align:start position:0% +away. Pick a point through here. Throw +it away. I pick a point here. Can't get + + align:start position:0% +it away. I pick a point here. Can't get + + + align:start position:0% +it away. I pick a point here. Can't get +to it. Doesn't do me any good. You know, + + align:start position:0% +to it. Doesn't do me any good. You know, + + + align:start position:0% +to it. Doesn't do me any good. You know, +after my after a very long time, maybe I + + align:start position:0% +after my after a very long time, maybe I + + + align:start position:0% +after my after a very long time, maybe I +luck out and I pick a point here, right? + + align:start position:0% +luck out and I pick a point here, right? + + + align:start position:0% +luck out and I pick a point here, right? +Okay. But then I have to wait and pick a + + align:start position:0% +Okay. But then I have to wait and pick a + + + align:start position:0% +Okay. But then I have to wait and pick a +point. Yeah, I pick a point here. I + + align:start position:0% +point. Yeah, I pick a point here. I + + + align:start position:0% +point. Yeah, I pick a point here. I +can't get to it. Just throw out, you + + align:start position:0% +can't get to it. Just throw out, you + + + align:start position:0% +can't get to it. Just throw out, you +know, I'm just completely hopeless. If + + align:start position:0% +know, I'm just completely hopeless. If + + + align:start position:0% +know, I'm just completely hopeless. If +it's in two dimensional space, then you + + align:start position:0% +it's in two dimensional space, then you + + + align:start position:0% +it's in two dimensional space, then you +can imagine sort of getting lucky enough + + align:start position:0% +can imagine sort of getting lucky enough + + + align:start position:0% +can imagine sort of getting lucky enough +or or designing a sampling distribution + + align:start position:0% +or or designing a sampling distribution + + + align:start position:0% +or or designing a sampling distribution +that does this. But let's say it's in + + align:start position:0% +that does this. But let's say it's in + + + align:start position:0% +that does this. But let's say it's in +some you know 14dimensional space that + + align:start position:0% +some you know 14dimensional space that + + + align:start position:0% +some you know 14dimensional space that +you have no idea where the tunnels the + + align:start position:0% +you have no idea where the tunnels the + + + align:start position:0% +you have no idea where the tunnels the +tubes are. Um there are some problems + + align:start position:0% +tubes are. Um there are some problems + + + align:start position:0% +tubes are. Um there are some problems +where RTS just choke. So in general when + + align:start position:0% +where RTS just choke. So in general when + + + align:start position:0% +where RTS just choke. So in general when +your space of solutions feasible + + align:start position:0% +your space of solutions feasible + + + align:start position:0% +your space of solutions feasible +solutions is small is + + align:start position:0% +solutions is small is + + + align:start position:0% +solutions is small is +that fair to say because like this is a + + align:start position:0% +that fair to say because like this is a + + + align:start position:0% +that fair to say because like this is a +small very small set of your total + + align:start position:0% +small very small set of your total + + + align:start position:0% +small very small set of your total +space. + + align:start position:0% +space. + + + align:start position:0% +space. +It's a little hard to say that, right? + + align:start position:0% +It's a little hard to say that, right? + + + align:start position:0% +It's a little hard to say that, right? +Because I I + + align:start position:0% +Because I I + + + align:start position:0% +Because I I +mean lots of trajectories work, right? + + align:start position:0% +mean lots of trajectories work, right? + + + align:start position:0% +mean lots of trajectories work, right? +They this one works, you know, right? + + align:start position:0% +They this one works, you know, right? + + + align:start position:0% +They this one works, you know, right? +This works, you know, but I think when + + align:start position:0% +This works, you know, but I think when + + + align:start position:0% +This works, you know, but I think when +there's narrow passages, that's when it + + align:start position:0% +there's narrow passages, that's when it + + + align:start position:0% +there's narrow passages, that's when it +really I think that's a a more clear way + + align:start position:0% +really I think that's a a more clear way + + + align:start position:0% +really I think that's a a more clear way +to say it when it chokes. + + align:start position:0% +to say it when it chokes. + + + align:start position:0% +to say it when it chokes. +And so when you say chokes, I mean it's, + + align:start position:0% +And so when you say chokes, I mean it's, + + + align:start position:0% +And so when you say chokes, I mean it's, +you know, as time goes to infinity, + + align:start position:0% +you know, as time goes to infinity, + + + align:start position:0% +you know, as time goes to infinity, +it'll finally find it. It is actually + + align:start position:0% +it'll finally find it. It is actually + + + align:start position:0% +it'll finally find it. It is actually +Santa. Yes. Okay. Good. + + align:start position:0% +Santa. Yes. Okay. Good. + + + align:start position:0% +Santa. Yes. Okay. Good. +So these algorithms um mostly what you + + align:start position:0% +So these algorithms um mostly what you + + + align:start position:0% +So these algorithms um mostly what you +look for in a planning algorithm is + + align:start position:0% +look for in a planning algorithm is + + + align:start position:0% +look for in a planning algorithm is +completeness. You want to know that as + + align:start position:0% +completeness. You want to know that as + + + align:start position:0% +completeness. You want to know that as +you as you expand all the nodes, you're + + align:start position:0% +you as you expand all the nodes, you're + + + align:start position:0% +you as you expand all the nodes, you're +eventually if there's a path to the + + align:start position:0% +eventually if there's a path to the + + + align:start position:0% +eventually if there's a path to the +goal, you'll find the path to the goal. + + align:start position:0% +goal, you'll find the path to the goal. + + + align:start position:0% +goal, you'll find the path to the goal. +And even if there's not a path, it'll + + align:start position:0% +And even if there's not a path, it'll + + + align:start position:0% +And even if there's not a path, it'll +tell you there's no path, right? RRTs + + align:start position:0% +tell you there's no path, right? RRTs + + + align:start position:0% +tell you there's no path, right? RRTs +have probabilistic completeness + + align:start position:0% +have probabilistic completeness + + + align:start position:0% +have probabilistic completeness +guarantees. They say if you expand + + align:start position:0% +guarantees. They say if you expand + + + align:start position:0% +guarantees. They say if you expand +enough nodes, then you'll with the + + align:start position:0% +enough nodes, then you'll with the + + + align:start position:0% +enough nodes, then you'll with the +probability one, if there is a path, + + align:start position:0% +probability one, if there is a path, + + + align:start position:0% +probability one, if there is a path, +you'll find it. Probabil probabilistic + + align:start position:0% +you'll find it. Probabil probabilistic + + + align:start position:0% +you'll find it. Probabil probabilistic +completeness doesn't do as much for + + align:start position:0% +completeness doesn't do as much for + + + align:start position:0% +completeness doesn't do as much for +disproving the existence of a path, + + align:start position:0% +disproving the existence of a path, + + + align:start position:0% +disproving the existence of a path, +right? it would take a very long time to + + align:start position:0% +right? it would take a very long time to + + + align:start position:0% +right? it would take a very long time to +disprove it. + + align:start position:0% +disprove it. + + + align:start position:0% +disprove it. +Um, but probabilistically these things + + align:start position:0% +Um, but probabilistically these things + + + align:start position:0% +Um, but probabilistically these things +will find a path to the goal if it + + align:start position:0% +will find a path to the goal if it + + + align:start position:0% +will find a path to the goal if it +exists. That's good. That's that's + + align:start position:0% +exists. That's good. That's that's + + + align:start position:0% +exists. That's good. That's that's +um maybe that'll make you sleep better + + align:start position:0% +um maybe that'll make you sleep better + + + align:start position:0% +um maybe that'll make you sleep better +at night. But if you wait if you have to + + align:start position:0% +at night. But if you wait if you have to + + + align:start position:0% +at night. But if you wait if you have to +wait, you know, for something to be + + align:start position:0% +wait, you know, for something to be + + + align:start position:0% +wait, you know, for something to be +probabistically complete, um it's not + + align:start position:0% +probabistically complete, um it's not + + + align:start position:0% +probabistically complete, um it's not +going to be useful. The reason these + + align:start position:0% +going to be useful. The reason these + + + align:start position:0% +going to be useful. The reason these +things are used like crazy is that in + + align:start position:0% +things are used like crazy is that in + + + align:start position:0% +things are used like crazy is that in +practice it they're very fast. They can + + align:start position:0% +practice it they're very fast. They can + + + align:start position:0% +practice it they're very fast. They can +be very very fast for finding good + + align:start position:0% +be very very fast for finding good + + + align:start position:0% +be very very fast for finding good +solutions. + + align:start position:0% +solutions. + + + align:start position:0% +solutions. +So really, I mean, the the uh the Grand + + align:start position:0% +So really, I mean, the the uh the Grand + + + align:start position:0% +So really, I mean, the the uh the Grand +Challenge vehicles using RTS all the + + align:start position:0% +Challenge vehicles using RTS all the + + + align:start position:0% +Challenge vehicles using RTS all the +time to consider possible future paths + + align:start position:0% +time to consider possible future paths + + + align:start position:0% +time to consider possible future paths +um along the street, trying to avoid + + align:start position:0% +um along the street, trying to avoid + + + align:start position:0% +um along the street, trying to avoid +obstacles. It's doing it fast enough um + + align:start position:0% +obstacles. It's doing it fast enough um + + + align:start position:0% +obstacles. It's doing it fast enough um +in sort of in a receding horizon way. + + align:start position:0% +in sort of in a receding horizon way. + + + align:start position:0% +in sort of in a receding horizon way. +It's always planning, you know, a minute + + align:start position:0% +It's always planning, you know, a minute + + + align:start position:0% +It's always planning, you know, a minute +ahead. I'm not sure exactly what the + + align:start position:0% +ahead. I'm not sure exactly what the + + + align:start position:0% +ahead. I'm not sure exactly what the +window is, you know, in driving time and + + align:start position:0% +window is, you know, in driving time and + + + align:start position:0% +window is, you know, in driving time and +it's doing it every DT roughly + + align:start position:0% +it's doing it every DT roughly + + + align:start position:0% +it's doing it every DT roughly +recomputing its plan, right? Right? + + align:start position:0% +recomputing its plan, right? Right? + + + align:start position:0% +recomputing its plan, right? Right? +These things can be really really fast + + align:start position:0% +These things can be really really fast + + + align:start position:0% +These things can be really really fast +in + + align:start position:0% + + + + align:start position:0% + +practice to some extent. Um the dynamic + + align:start position:0% +practice to some extent. Um the dynamic + + + align:start position:0% +practice to some extent. Um the dynamic +constraints which we're talking about on + + align:start position:0% +constraints which we're talking about on + + + align:start position:0% +constraints which we're talking about on +the + + align:start position:0% +the + + + align:start position:0% +the +pendulum are exactly this + + align:start position:0% + + + + align:start position:0% + +problem, + + align:start position:0% +problem, + + + align:start position:0% +problem, +right? Because the because the pendulum + + align:start position:0% +right? Because the because the pendulum + + + align:start position:0% +right? Because the because the pendulum +like we said it's it's coming here. We + + align:start position:0% +like we said it's it's coming here. We + + + align:start position:0% +like we said it's it's coming here. We +know what the the phase portrait of the + + align:start position:0% +know what the the phase portrait of the + + + align:start position:0% +know what the the phase portrait of the +pendulum look like and we know that if + + align:start position:0% +pendulum look like and we know that if + + + align:start position:0% +pendulum look like and we know that if +we're torque limited there's only a + + align:start position:0% +we're torque limited there's only a + + + align:start position:0% +we're torque limited there's only a +handful of places we can go to some + + align:start position:0% +handful of places we can go to some + + + align:start position:0% +handful of places we can go to some +extent kodnamic + + align:start position:0% +extent kodnamic + + + align:start position:0% +extent kodnamic +constraints like this dynamics um can + + align:start position:0% +constraints like this dynamics um can + + + align:start position:0% +constraints like this dynamics um can +look exactly like + + align:start position:0% +look exactly like + + + align:start position:0% +look exactly like +this. So if you take your vanilla RT you + + align:start position:0% +this. So if you take your vanilla RT you + + + align:start position:0% +this. So if you take your vanilla RT you +saw how effectively it grew on the + + align:start position:0% +saw how effectively it grew on the + + + align:start position:0% +saw how effectively it grew on the +pendulum. It took a lot a lot of nodes + + align:start position:0% +pendulum. It took a lot a lot of nodes + + + align:start position:0% +pendulum. It took a lot a lot of nodes +to to find its way out. Um the hope is + + align:start position:0% +to to find its way out. Um the hope is + + + align:start position:0% +to to find its way out. Um the hope is +that we know enough about this sort of + + align:start position:0% +that we know enough about this sort of + + + align:start position:0% +that we know enough about this sort of +dynamical system from our some of our + + align:start position:0% +dynamical system from our some of our + + + align:start position:0% +dynamical system from our some of our +other tools like LQR to do a distance + + align:start position:0% +other tools like LQR to do a distance + + + align:start position:0% +other tools like LQR to do a distance +metric from tricks like this then we can + + align:start position:0% +metric from tricks like this then we can + + + align:start position:0% +metric from tricks like this then we can +that we're effectively guiding this + + align:start position:0% +that we're effectively guiding this + + + align:start position:0% +that we're effectively guiding this +thing down down the differential + + align:start position:0% +thing down down the differential + + + align:start position:0% +thing down down the differential +constraint + + align:start position:0% + + + + align:start position:0% + +tubes. Has there been any work with + + align:start position:0% +tubes. Has there been any work with + + + align:start position:0% +tubes. Has there been any work with +relaxing the number? Like for example, + + align:start position:0% +relaxing the number? Like for example, + + + align:start position:0% +relaxing the number? Like for example, +if you have like 15 dimensional robot, + + align:start position:0% +if you have like 15 dimensional robot, + + + align:start position:0% +if you have like 15 dimensional robot, +you want to get to go position and you + + align:start position:0% +you want to get to go position and you + + + align:start position:0% +you want to get to go position and you +relax some of those dimensions and then + + align:start position:0% +relax some of those dimensions and then + + + align:start position:0% +relax some of those dimensions and then +use the rest of it, design a control in + + align:start position:0% +use the rest of it, design a control in + + + align:start position:0% +use the rest of it, design a control in +a very low dimensional state space and + + align:start position:0% +a very low dimensional state space and + + + align:start position:0% +a very low dimensional state space and +then use that as a heristic. Awesome. + + align:start position:0% +then use that as a heristic. Awesome. + + + align:start position:0% +then use that as a heristic. Awesome. +Um, yes. So uh so Alec also had tell you + + align:start position:0% +Um, yes. So uh so Alec also had tell you + + + align:start position:0% +Um, yes. So uh so Alec also had tell you +what my next + + align:start position:0% +what my next + + + align:start position:0% +what my next +slide right + + align:start position:0% +slide right + + + align:start position:0% +slide right +uh this is Alex's other thing about uh + + align:start position:0% +uh this is Alex's other thing about uh + + + align:start position:0% +uh this is Alex's other thing about uh +planning in a task space which is + + align:start position:0% +planning in a task space which is + + + align:start position:0% +planning in a task space which is +exactly what you said I think there's + + align:start position:0% +exactly what you said I think there's + + + align:start position:0% +exactly what you said I think there's +lots of ways to do it I think Alec found + + align:start position:0% +lots of ways to do it I think Alec found + + + align:start position:0% +lots of ways to do it I think Alec found +a really good way to do it um this is + + align:start position:0% +a really good way to do it um this is + + + align:start position:0% +a really good way to do it um this is +just an example of a um a fivelink + + align:start position:0% +just an example of a um a fivelink + + + align:start position:0% +just an example of a um a fivelink +robotic arm just in configuration space + + align:start position:0% +robotic arm just in configuration space + + + align:start position:0% +robotic arm just in configuration space +that had to find its its way from that + + align:start position:0% +that had to find its its way from that + + + align:start position:0% +that had to find its its way from that +endpoint effect to the the goal + + align:start position:0% +endpoint effect to the the goal + + + align:start position:0% +endpoint effect to the the goal +endpoint. So you see at the top that + + align:start position:0% +endpoint. So you see at the top that + + + align:start position:0% +endpoint. So you see at the top that +little green arm is the resulting + + align:start position:0% +little green arm is the resulting + + + align:start position:0% +little green arm is the resulting +configuration of the robot. The standard + + align:start position:0% +configuration of the robot. The standard + + + align:start position:0% +configuration of the robot. The standard +RT looked all over the place to try to + + align:start position:0% +RT looked all over the place to try to + + + align:start position:0% +RT looked all over the place to try to +find that solution. If you instead just + + align:start position:0% +find that solution. If you instead just + + + align:start position:0% +find that solution. If you instead just +you it's a little subtle how we had to + + align:start position:0% +you it's a little subtle how we had to + + + align:start position:0% +you it's a little subtle how we had to +do it. You had to basically change the + + align:start position:0% +do it. You had to basically change the + + + align:start position:0% +do it. You had to basically change the +Voronoi bias to live in the in the uh + + align:start position:0% +Voronoi bias to live in the in the uh + + + align:start position:0% +Voronoi bias to live in the in the uh +task space but still sample uniformly + + align:start position:0% +task space but still sample uniformly + + + align:start position:0% +task space but still sample uniformly +from the other space. So that's not + + align:start position:0% +from the other space. So that's not + + + align:start position:0% +from the other space. So that's not +enough to tell you how to do it but + + align:start position:0% +enough to tell you how to do it but + + + align:start position:0% +enough to tell you how to do it but +that's enough to tell you it's not + + align:start position:0% +that's enough to tell you it's not + + + align:start position:0% +that's enough to tell you it's not +completely trivial. + + align:start position:0% +completely trivial. + + + align:start position:0% +completely trivial. +Uh then then he found these really + + align:start position:0% +Uh then then he found these really + + + align:start position:0% +Uh then then he found these really +really elegant solutions um to to plan + + align:start position:0% +really elegant solutions um to to plan + + + align:start position:0% +really elegant solutions um to to plan +in task space. And the the results his + + align:start position:0% +in task space. And the the results his + + + align:start position:0% +in task space. And the the results his +his sort of killer plot is that this is + + align:start position:0% +his sort of killer plot is that this is + + + align:start position:0% +his sort of killer plot is that this is +the number of um number of links in the + + align:start position:0% +the number of um number of links in the + + + align:start position:0% +the number of um number of links in the +robotic arm, right? Versus the number of + + align:start position:0% +robotic arm, right? Versus the number of + + + align:start position:0% +robotic arm, right? Versus the number of +nodes it took to find the goal. And the + + align:start position:0% +nodes it took to find the goal. And the + + + align:start position:0% +nodes it took to find the goal. And the +standard + + align:start position:0% +standard + + + align:start position:0% +standard +RT went like that. And after, you know, + + align:start position:0% +RT went like that. And after, you know, + + + align:start position:0% +RT went like that. And after, you know, +10 links, it just was hopeless. And + + align:start position:0% +10 links, it just was hopeless. And + + + align:start position:0% +10 links, it just was hopeless. And +after uh with with n going to over a + + align:start position:0% +after uh with with n going to over a + + + align:start position:0% +after uh with with n going to over a +thousand dimensions he was just planning + + align:start position:0% +thousand dimensions he was just planning + + + align:start position:0% +thousand dimensions he was just planning +in constant time basically right so yeah + + align:start position:0% +in constant time basically right so yeah + + + align:start position:0% +in constant time basically right so yeah +there's there's structure in the + + align:start position:0% +there's there's structure in the + + + align:start position:0% +there's there's structure in the +problems right + + align:start position:0% +problems right + + + align:start position:0% +problems right +um we also have a using the partial + + align:start position:0% +um we also have a using the partial + + + align:start position:0% +um we also have a using the partial +feedback linearization task space have + + align:start position:0% +feedback linearization task space have + + + align:start position:0% +feedback linearization task space have +tried doing it in underactuated systems + + align:start position:0% +tried doing it in underactuated systems + + + align:start position:0% +tried doing it in underactuated systems +um uh and and that sort of works too. + + align:start position:0% +um uh and and that sort of works too. + + + align:start position:0% +um uh and and that sort of works too. +Yeah, but it's not the norm. + + align:start position:0% +Yeah, but it's not the norm. + + + align:start position:0% +Yeah, but it's not the norm. +Actually, it's not the accepted version + + align:start position:0% +Actually, it's not the accepted version + + + align:start position:0% +Actually, it's not the accepted version +of the algorithm + + align:start position:0% + + + + align:start position:0% + +yet. RTS are beautiful things, right? + + align:start position:0% +yet. RTS are beautiful things, right? + + + align:start position:0% +yet. RTS are beautiful things, right? +They just grow on out, find their way to + + align:start position:0% +They just grow on out, find their way to + + + align:start position:0% +They just grow on out, find their way to +the goal. What potential complaint is + + align:start position:0% +the goal. What potential complaint is + + + align:start position:0% +the goal. What potential complaint is +when you're when you're done with it, + + align:start position:0% +when you're when you're done with it, + + + align:start position:0% +when you're when you're done with it, +you've got this sort of choppy uh disc + + align:start position:0% +you've got this sort of choppy uh disc + + + align:start position:0% +you've got this sort of choppy uh disc +discretized path that gets you to the + + align:start position:0% +discretized path that gets you to the + + + align:start position:0% +discretized path that gets you to the +goal, but then just hand it to your + + align:start position:0% +goal, but then just hand it to your + + + align:start position:0% +goal, but then just hand it to your +trajectory optimizer as an initial + + align:start position:0% +trajectory optimizer as an initial + + + align:start position:0% +trajectory optimizer as an initial +condition and let it smooth it out. + + align:start position:0% +condition and let it smooth it out. + + + align:start position:0% +condition and let it smooth it out. +Right? still satisfying obstacle + + align:start position:0% +Right? still satisfying obstacle + + + align:start position:0% +Right? still satisfying obstacle +constraints, torque constraints. We know + + align:start position:0% +constraints, torque constraints. We know + + + align:start position:0% +constraints, torque constraints. We know +how to do that and smooth it out and + + align:start position:0% +how to do that and smooth it out and + + + align:start position:0% +how to do that and smooth it out and +you've got yourself a good trajectory + + align:start position:0% +you've got yourself a good trajectory + + + align:start position:0% +you've got yourself a good trajectory +that gets from the start to the goal. + + align:start position:0% +that gets from the start to the goal. + + + align:start position:0% +that gets from the start to the goal. +It's a beautiful thing. People didn't I + + align:start position:0% +It's a beautiful thing. People didn't I + + + align:start position:0% +It's a beautiful thing. People didn't I +mean I think I to the point where Tomas + + align:start position:0% +mean I think I to the point where Tomas + + + align:start position:0% +mean I think I to the point where Tomas +Lozano Perez, right, invented + + align:start position:0% +Lozano Perez, right, invented + + + align:start position:0% +Lozano Perez, right, invented +configuration space, did motion planning + + align:start position:0% +configuration space, did motion planning + + + align:start position:0% +configuration space, did motion planning +for however long. He actually stopped + + align:start position:0% +for however long. He actually stopped + + + align:start position:0% +for however long. He actually stopped +robotics, went off and did computational + + align:start position:0% +robotics, went off and did computational + + + align:start position:0% +robotics, went off and did computational +biology for a while. And he says he came + + align:start position:0% +biology for a while. And he says he came + + + align:start position:0% +biology for a while. And he says he came +back to robotics this a few years ago + + align:start position:0% +back to robotics this a few years ago + + + align:start position:0% +back to robotics this a few years ago +because these kind of algorithms made a + + align:start position:0% +because these kind of algorithms made a + + + align:start position:0% +because these kind of algorithms made a +difference to the point where it was + + align:start position:0% +difference to the point where it was + + + align:start position:0% +difference to the point where it was +worth doing motion planning or robotics + + align:start position:0% +worth doing motion planning or robotics + + + align:start position:0% +worth doing motion planning or robotics +again. Yeah. I don't know a a more + + align:start position:0% +again. Yeah. I don't know a a more + + + align:start position:0% +again. Yeah. I don't know a a more +dramatic thing to say than that. + + align:start position:0% + + + + align:start position:0% + +Yeah. Okay. So next time I'm going to go + + align:start position:0% +Yeah. Okay. So next time I'm going to go + + + align:start position:0% +Yeah. Okay. So next time I'm going to go +a little bit um um more into the using + + align:start position:0% +a little bit um um more into the using + + + align:start position:0% +a little bit um um more into the using +these planning algorithms and and also + + align:start position:0% +these planning algorithms and and also + + + align:start position:0% +these planning algorithms and and also +feedback motion planning um applied to + + align:start position:0% +feedback motion planning um applied to + + + align:start position:0% +feedback motion planning um applied to +our model systems. But I I don't want to + + align:start position:0% +our model systems. But I I don't want to + + + align:start position:0% +our model systems. But I I don't want to +completely + + align:start position:0% + + + + align:start position:0% + +satur I mean the idea that a randomized + + align:start position:0% +satur I mean the idea that a randomized + + + align:start position:0% +satur I mean the idea that a randomized +algorithm can do better than our our + + align:start position:0% +algorithm can do better than our our + + + align:start position:0% +algorithm can do better than our our +explicit algorithms. It's all these + + align:start position:0% +explicit algorithms. It's all these + + + align:start position:0% +explicit algorithms. It's all these +these funny things. There's classes on + + align:start position:0% +these funny things. There's classes on + + + align:start position:0% +these funny things. There's classes on +randomized algorithms here. Every once + + align:start position:0% +randomized algorithms here. Every once + + + align:start position:0% +randomized algorithms here. Every once +in a while these things just really work + + align:start position:0% +in a while these things just really work + + + align:start position:0% +in a while these things just really work +nicely. Randomization can help, right? + + align:start position:0% +nicely. Randomization can help, right? + + + align:start position:0% +nicely. Randomization can help, right? +And the reason roughly maybe is that + + align:start position:0% +And the reason roughly maybe is that + + + align:start position:0% +And the reason roughly maybe is that +it's it's actually pretty cheap to pick + + align:start position:0% +it's it's actually pretty cheap to pick + + + align:start position:0% +it's it's actually pretty cheap to pick +a sample point. It's pretty cheap to + + align:start position:0% +a sample point. It's pretty cheap to + + + align:start position:0% +a sample point. It's pretty cheap to +evaluate if it's in a in a collision. Um + + align:start position:0% +evaluate if it's in a in a collision. Um + + + align:start position:0% +evaluate if it's in a in a collision. Um +and and so so why not just pick a lot + + align:start position:0% +and and so so why not just pick a lot + + + align:start position:0% +and and so so why not just pick a lot +instead of trying to reason about the + + align:start position:0% +instead of trying to reason about the + + + align:start position:0% +instead of trying to reason about the +geometry of your obstacles, right? + + align:start position:0% +geometry of your obstacles, right? + + + align:start position:0% +geometry of your obstacles, right? +Building configuration spaces, that's + + align:start position:0% +Building configuration spaces, that's + + + align:start position:0% +Building configuration spaces, that's +hard compared to just saying, "Okay, + + align:start position:0% +hard compared to just saying, "Okay, + + + align:start position:0% +hard compared to just saying, "Okay, +what if my robot was here? Was that a + + align:start position:0% +what if my robot was here? Was that a + + + align:start position:0% +what if my robot was here? Was that a +collision?" "Yeah, that's in collision." + + align:start position:0% +collision?" "Yeah, that's in collision." + + + align:start position:0% +collision?" "Yeah, that's in collision." +Okay, throw it out. And just sometimes + + align:start position:0% +Okay, throw it out. And just sometimes + + + align:start position:0% +Okay, throw it out. And just sometimes +randomized algorithms are + + align:start position:0% +randomized algorithms are + + + align:start position:0% +randomized algorithms are +better. Okay, see you next week. \ No newline at end of file diff --git a/v-5w8ZDIa4w.txt b/v-5w8ZDIa4w.txt new file mode 100644 index 0000000000000000000000000000000000000000..225d53b3e78ee8ca44b0783cea7523c4a7734290 --- /dev/null +++ b/v-5w8ZDIa4w.txt @@ -0,0 +1,263 @@ +We're on the home stretch now. + +For all the instructions up until now, the +next instruction has come from the location + +following the current instruction - hence +the "PC+4" logic. + +Branches and JMPs change that by altering +the value in the PC. + +The JMP instruction simply takes the value +in the RA register and makes it the next PC + +value. + +The PCSEL MUX in the upper left-hand corner +lets the control logic select the source of + +the next PC value. + +When PCSEL is 0, the incremented PC value +is chosen. + +When PCSEL is 2, the value of the RA register +is chosen. + +We'll see how the other inputs to the PCSEL +MUX are used in just a moment. + +The JMP and branch instructions also cause +the address of the following instruction, + +i.e., the PC+4 value, to be written to the +RC register. + +When WDSEL is 0, the "0" input of the WDSEL +MUX is used to select the PC+4 value as the + +write-back data. + +Here's how the data flow works. + +The output of the PC+4 adder is is routed +to the register file and WERF is set to 1 + +to enable that value to be written at the +end of the cycle. + +Meanwhile, the value of RA register coming +out of the register file is connected to the + +"2" input of the PCSEL MUX. + +So setting PCSEL to 2 will select the value +in the RA register as the next value for the + +PC. + +The rest of the control signals are "don't +cares", except, of course for the memory write + +enable (MWR), which can never be "don't care" +lest we cause an accidental write to some + +memory location. + +The branch instruction requires an additional +adder to compute the target address by adding + +the scaled offset from the instruction's literal +field to the current PC+4 value. + +Remember that we scale the offset by a factor +of 4 to convert it from the word offset stored + +in the literal to the byte offset required +for the PC. + +The output of the offset adder becomes the +"1" input to the PCSEL MUX, where, if the + +branch is taken, it will become the next value +of the PC. + +Note that multiplying by 4 is easily accomplished +by shifting the literal two bits to the left, + +which inserts two 0-bits at the low-order +end of the value. + +And, like before, the sign-extension just +requires replicating bit ID[15], in this case + +fourteen times. + +So implementing this complicated-looking expression +requires care in wiring up the input to the + +offset adder, but no additional logic! + +We do need some logic to determine if we should +branch or not. + +The 32-bit NOR gate connected to the first +read port of the register file tests the value + +of the RA register. + +The NOR's output Z will be 1 if all the bits +of the RA register value are 0, and 0 otherwise. + +The Z value can be used by the control logic +to determine the correct value for PCSEL. + +If Z indicates the branch is taken, PCSEL +will be 1 and the output of the offset adder + +becomes the next value of the PC. + +If the branch is not taken, PCSEL will be +0 and execution will continue with the next + +instruction at PC+4. + +As in the JMP instruction, the PC+4 value +is routed to the register file to be written + +into the RC register at end of the cycle. + +Meanwhile, the value of Z is computed from +the value of the RA register while the branch + +offset adder computes the address of the branch +target. + +The output of the offset adder is routed to +the PCSEL MUX where the value of the 3-bit + +PCSEL control signal, computed by the control +logic based on Z, determines whether the next + +PC value is the branch target or the PC+4 +value. + +The remaining control signals are unused and +set to their default "don't care" values. + +We have one last instruction to introduce: +the LDR or load-relative instruction. + +LDR behaves like a normal LD instruction except +that the memory address is taken from the + +branch offset adder. + +Why would it be useful to load a value from +a location near the LDR instruction? + +Normally such addresses would refer to the +neighboring instructions, so why would we + +want to load the binary encoding of an instruction +into a register to be used as data? + +The use case for LDR is accessing large constants +that have to be stored in main memory because + +they are too large to fit into the 16-bit +literal field of an instruction. + +In the example shown here, the compiled code +needs to load the constant 123456. + +So it uses an LDR instruction that refers +to a nearby location C1: that has been initialized + +with the required value. + +Since this read-only constant is part of the +program, it makes sense to store it with the + +instructions for the program, usually just +after the code for a procedure. + +Note that we have to be careful to place the +storage location so that it won't be executed + +as an instruction! + +To route the output of the offset adder to +the main memory address port, we'll add ASEL + +MUX so we can select either the RA register +value (when ASEL=0) or the output of the offset + +adder (when ASEL=1) as the first ALU operand. + +For LDR, ASEL will be 1, and we'll then ask +the ALU compute the Boolean operation "A", + +i.e., the boolean function whose output is +just the value of the first operand. + +This value then appears on the ALU output, +which is connected to the main memory address + +port and the remainder of the execution proceeds +just like it did for LD. + +This seems a bit complicated! + +Mr. Blue has a good question: +why not just put the ASEL MUX on the wire + +leading to the main memory address port and +bypass the ALU altogether? + +The answer has to do with the amount of time +needed to compute the memory address. + +If we moved the ASEL MUX here, the data flow +for LD and ST addresses would then pass through + +two MUXes, the BSEL MUX and the ASEL MUX, +slowing down the arrival of the address by + +a small amount. + +This may not seem like a big deal, but the +additional time would have to be added the + +clock period, thus slowing down every instruction +by a little bit. + +When executing billions of instructions, a +little extra time on each instruction really + +impacts the overall performance of the processor. + +By placing the ASEL MUX where we did, its +propagation delay overlaps that of the BSEL + +MUX, so the increased functionality it provides +comes with no cost in performance. + +Here's the data flow for the LDR instruction. + +The output of the offset adder is routed through +the ASEL MUX to the ALU. + +The ALU performs the Boolean computation "A" +and the result becomes the address for main + +memory. + +The returning data is routed through the WDSEL +MUX so it can be written into the RC register + +at the end of the cycle. + +The remaining control values are given their +usual default values. \ No newline at end of file diff --git a/vJAG4EzSQZA.txt b/vJAG4EzSQZA.txt new file mode 100644 index 0000000000000000000000000000000000000000..d13434245bd4c5d5976345eeb02c9257a6ce9c84 --- /dev/null +++ b/vJAG4EzSQZA.txt @@ -0,0 +1,931 @@ +align:start position:0% + +we will now talk about conditional + + align:start position:0% +we will now talk about conditional + + + align:start position:0% +we will now talk about conditional +expectations of one random variable + + align:start position:0% +expectations of one random variable + + + align:start position:0% +expectations of one random variable +given another as we will see there will + + align:start position:0% +given another as we will see there will + + + align:start position:0% +given another as we will see there will +be nothing new here except for all the + + align:start position:0% +be nothing new here except for all the + + + align:start position:0% +be nothing new here except for all the +results but given a new notation any PMF + + align:start position:0% +results but given a new notation any PMF + + + align:start position:0% +results but given a new notation any PMF +has an Associated expectation and so + + align:start position:0% +has an Associated expectation and so + + + align:start position:0% +has an Associated expectation and so +conditional pmfs also have associated + + align:start position:0% +conditional pmfs also have associated + + + align:start position:0% +conditional pmfs also have associated +expectations which we call conditional + + align:start position:0% +expectations which we call conditional + + + align:start position:0% +expectations which we call conditional +expectations we have already seen them + + align:start position:0% +expectations we have already seen them + + + align:start position:0% +expectations we have already seen them +for the case where we conditioned on an + + align:start position:0% +for the case where we conditioned on an + + + align:start position:0% +for the case where we conditioned on an +event a the case where we conditioned on + + align:start position:0% +event a the case where we conditioned on + + + align:start position:0% +event a the case where we conditioned on +random variables is exactly the same we + + align:start position:0% +random variables is exactly the same we + + + align:start position:0% +random variables is exactly the same we +let the event a be the event that Y + + align:start position:0% +let the event a be the event that Y + + + align:start position:0% +let the event a be the event that Y +takes on a specific value and then we + + align:start position:0% +takes on a specific value and then we + + + align:start position:0% +takes on a specific value and then we +calculate the expectation using the + + align:start position:0% +calculate the expectation using the + + + align:start position:0% +calculate the expectation using the +relevant conditional probabilities those + + align:start position:0% +relevant conditional probabilities those + + + align:start position:0% +relevant conditional probabilities those +that are given by the conditional pmf so + + align:start position:0% +that are given by the conditional pmf so + + + align:start position:0% +that are given by the conditional pmf so +the conditional expectation of x given + + align:start position:0% +the conditional expectation of x given + + + align:start position:0% +the conditional expectation of x given +that Y takes on a certain value is + + align:start position:0% +that Y takes on a certain value is + + + align:start position:0% +that Y takes on a certain value is +defined as the usual expectation except + + align:start position:0% +defined as the usual expectation except + + + align:start position:0% +defined as the usual expectation except +that we use the conditional + + align:start position:0% +that we use the conditional + + + align:start position:0% +that we use the conditional +probabilities that apply given that Y + + align:start position:0% +probabilities that apply given that Y + + + align:start position:0% +probabilities that apply given that Y +takes on a specific value little Y + + align:start position:0% +takes on a specific value little Y + + + align:start position:0% +takes on a specific value little Y +recall now the expected value rule for + + align:start position:0% +recall now the expected value rule for + + + align:start position:0% +recall now the expected value rule for +ordinary expectations and also the + + align:start position:0% +ordinary expectations and also the + + + align:start position:0% +ordinary expectations and also the +expected value rule for conditional + + align:start position:0% +expected value rule for conditional + + + align:start position:0% +expected value rule for conditional +expectations given an event something + + align:start position:0% +expectations given an event something + + + align:start position:0% +expectations given an event something +that we have already seen now in PMF + + align:start position:0% +that we have already seen now in PMF + + + align:start position:0% +that we have already seen now in PMF +notation the expected value rule takes a + + align:start position:0% +notation the expected value rule takes a + + + align:start position:0% +notation the expected value rule takes a +similar form the event a is replaced by + + align:start position:0% +similar form the event a is replaced by + + + align:start position:0% +similar form the event a is replaced by +the specific event that Y takes on a + + align:start position:0% +the specific event that Y takes on a + + + align:start position:0% +the specific event that Y takes on a +specific value and in that case the + + align:start position:0% +specific value and in that case the + + + align:start position:0% +specific value and in that case the +conditional pmf given the event a is + + align:start position:0% +conditional pmf given the event a is + + + align:start position:0% +conditional pmf given the event a is +just the conditional pmf given that + + align:start position:0% +just the conditional pmf given that + + + align:start position:0% +just the conditional pmf given that +random variable Y takes on a specific + + align:start position:0% +random variable Y takes on a specific + + + align:start position:0% +random variable Y takes on a specific +value little Y for the case where we + + align:start position:0% +value little Y for the case where we + + + align:start position:0% +value little Y for the case where we +conditioned on events we also developed + + align:start position:0% +conditioned on events we also developed + + + align:start position:0% +conditioned on events we also developed +a version of the total probability + + align:start position:0% +a version of the total probability + + + align:start position:0% +a version of the total probability +theorem and the total expectation + + align:start position:0% +theorem and the total expectation + + + align:start position:0% +theorem and the total expectation +theorem we can do the same when we + + align:start position:0% +theorem we can do the same when we + + + align:start position:0% +theorem we can do the same when we +conditioned on random variables so + + align:start position:0% +conditioned on random variables so + + + align:start position:0% +conditioned on random variables so +suppose that the sample space has been + + align:start position:0% +suppose that the sample space has been + + + align:start position:0% +suppose that the sample space has been +partitioned into + + align:start position:0% +partitioned into + + + align:start position:0% +partitioned into +and disjoint scenarios the total + + align:start position:0% +and disjoint scenarios the total + + + align:start position:0% +and disjoint scenarios the total +probability theorem tells us that the + + align:start position:0% +probability theorem tells us that the + + + align:start position:0% +probability theorem tells us that the +probability of the event the event that + + align:start position:0% +probability of the event the event that + + + align:start position:0% +probability of the event the event that +random variable X takes on value little + + align:start position:0% +random variable X takes on value little + + + align:start position:0% +random variable X takes on value little +X can be found by taking the + + align:start position:0% +X can be found by taking the + + + align:start position:0% +X can be found by taking the +probabilities of this event under each + + align:start position:0% +probabilities of this event under each + + + align:start position:0% +probabilities of this event under each +one of the possible scenarios and then + + align:start position:0% +one of the possible scenarios and then + + + align:start position:0% +one of the possible scenarios and then +weighing those probabilities according + + align:start position:0% +weighing those probabilities according + + + align:start position:0% +weighing those probabilities according +to the probabilities of the different + + align:start position:0% +to the probabilities of the different + + + align:start position:0% +to the probabilities of the different +scenarios now suppose that we are + + align:start position:0% +scenarios now suppose that we are + + + align:start position:0% +scenarios now suppose that we are +dealing with a random variable that + + align:start position:0% +dealing with a random variable that + + + align:start position:0% +dealing with a random variable that +takes values in a set consisting of n + + align:start position:0% +takes values in a set consisting of n + + + align:start position:0% +takes values in a set consisting of n +elements and let us consider scenarios + + align:start position:0% +elements and let us consider scenarios + + + align:start position:0% +elements and let us consider scenarios +AI the eigth scenario is the event that + + align:start position:0% +AI the eigth scenario is the event that + + + align:start position:0% +AI the eigth scenario is the event that +the random variable Y takes on the eyes + + align:start position:0% +the random variable Y takes on the eyes + + + align:start position:0% +the random variable Y takes on the eyes +possible value we can apply the total + + align:start position:0% +possible value we can apply the total + + + align:start position:0% +possible value we can apply the total +probability theorem to this situation we + + align:start position:0% +probability theorem to this situation we + + + align:start position:0% +probability theorem to this situation we +can find the probability that the random + + align:start position:0% +can find the probability that the random + + + align:start position:0% +can find the probability that the random +variable X takes on a certain value + + align:start position:0% +variable X takes on a certain value + + + align:start position:0% +variable X takes on a certain value +little X by considering the probability + + align:start position:0% +little X by considering the probability + + + align:start position:0% +little X by considering the probability +of this event happening under each + + align:start position:0% +of this event happening under each + + + align:start position:0% +of this event happening under each +possible scenario where a scenario is + + align:start position:0% +possible scenario where a scenario is + + + align:start position:0% +possible scenario where a scenario is +that Y took on a specific value and then + + align:start position:0% +that Y took on a specific value and then + + + align:start position:0% +that Y took on a specific value and then +weigh those probabilities according to + + align:start position:0% +weigh those probabilities according to + + + align:start position:0% +weigh those probabilities according to +the probabilities of the different + + align:start position:0% +the probabilities of the different + + + align:start position:0% +the probabilities of the different +scenarios the story with the total + + align:start position:0% +scenarios the story with the total + + + align:start position:0% +scenarios the story with the total +expectation theorem is similar we know + + align:start position:0% +expectation theorem is similar we know + + + align:start position:0% +expectation theorem is similar we know +that an expectation can be found by + + align:start position:0% +that an expectation can be found by + + + align:start position:0% +that an expectation can be found by +taking the conditional expectations + + align:start position:0% +taking the conditional expectations + + + align:start position:0% +taking the conditional expectations +under each one of the scenarios and + + align:start position:0% +under each one of the scenarios and + + + align:start position:0% +under each one of the scenarios and +weighing them according to the + + align:start position:0% +weighing them according to the + + + align:start position:0% +weighing them according to the +probabilities of the different scenarios + + align:start position:0% +probabilities of the different scenarios + + + align:start position:0% +probabilities of the different scenarios +again let the event that Y takes on a + + align:start position:0% +again let the event that Y takes on a + + + align:start position:0% +again let the event that Y takes on a +specific value be a different scenario + + align:start position:0% +specific value be a different scenario + + + align:start position:0% +specific value be a different scenario +and with this correspondence we obtain + + align:start position:0% +and with this correspondence we obtain + + + align:start position:0% +and with this correspondence we obtain +the following version of the total + + align:start position:0% +the following version of the total + + + align:start position:0% +the following version of the total +expectation theorem we have a sum of + + align:start position:0% +expectation theorem we have a sum of + + + align:start position:0% +expectation theorem we have a sum of +different terms and each term in the sum + + align:start position:0% +different terms and each term in the sum + + + align:start position:0% +different terms and each term in the sum +is the probability of a given scenario + + align:start position:0% +is the probability of a given scenario + + + align:start position:0% +is the probability of a given scenario +times the expected value of X under this + + align:start position:0% +times the expected value of X under this + + + align:start position:0% +times the expected value of X under this +part + + align:start position:0% +part + + + align:start position:0% +part +stickler scenario at this point I have + + align:start position:0% +stickler scenario at this point I have + + + align:start position:0% +stickler scenario at this point I have +to add the comment of a more + + align:start position:0% +to add the comment of a more + + + align:start position:0% +to add the comment of a more +mathematical flavor we have been talking + + align:start position:0% +mathematical flavor we have been talking + + + align:start position:0% +mathematical flavor we have been talking +about the partition of the sample space + + align:start position:0% +about the partition of the sample space + + + align:start position:0% +about the partition of the sample space +into finitely many scenarios but if Y + + align:start position:0% +into finitely many scenarios but if Y + + + align:start position:0% +into finitely many scenarios but if Y +takes on values ended in a discrete but + + align:start position:0% +takes on values ended in a discrete but + + + align:start position:0% +takes on values ended in a discrete but +infinite set for example if Y can take + + align:start position:0% +infinite set for example if Y can take + + + align:start position:0% +infinite set for example if Y can take +on any integer value the argument that + + align:start position:0% +on any integer value the argument that + + + align:start position:0% +on any integer value the argument that +we have given is not quite complete + + align:start position:0% +we have given is not quite complete + + + align:start position:0% +we have given is not quite complete +fortunately the total probability + + align:start position:0% +fortunately the total probability + + + align:start position:0% +fortunately the total probability +theorem and the total expectation + + align:start position:0% +theorem and the total expectation + + + align:start position:0% +theorem and the total expectation +theorem they both remain true even for + + align:start position:0% +theorem they both remain true even for + + + align:start position:0% +theorem they both remain true even for +the case where Y ranges over an infinite + + align:start position:0% +the case where Y ranges over an infinite + + + align:start position:0% +the case where Y ranges over an infinite +set as long as the random variable X has + + align:start position:0% +set as long as the random variable X has + + + align:start position:0% +set as long as the random variable X has +a well-defined expectation for the total + + align:start position:0% +a well-defined expectation for the total + + + align:start position:0% +a well-defined expectation for the total +probability theorem the proof for the + + align:start position:0% +probability theorem the proof for the + + + align:start position:0% +probability theorem the proof for the +general case can be carried out without + + align:start position:0% +general case can be carried out without + + + align:start position:0% +general case can be carried out without +a lot of difficulty just using the + + align:start position:0% +a lot of difficulty just using the + + + align:start position:0% +a lot of difficulty just using the +countable additivity axiom however for + + align:start position:0% +countable additivity axiom however for + + + align:start position:0% +countable additivity axiom however for +the total expectation theorem it takes + + align:start position:0% +the total expectation theorem it takes + + + align:start position:0% +the total expectation theorem it takes +some harder mathematical work and this + + align:start position:0% +some harder mathematical work and this + + + align:start position:0% +some harder mathematical work and this +is beyond our scope but we will just + + align:start position:0% +is beyond our scope but we will just + + + align:start position:0% +is beyond our scope but we will just +take this fact for granted that the + + align:start position:0% +take this fact for granted that the + + + align:start position:0% +take this fact for granted that the +total expectation theorem carries over + + align:start position:0% +total expectation theorem carries over + + + align:start position:0% +total expectation theorem carries over +to the case where we are adding over an + + align:start position:0% +to the case where we are adding over an + + + align:start position:0% +to the case where we are adding over an +infinite sequence of possible values of + + align:start position:0% +infinite sequence of possible values of + + + align:start position:0% +infinite sequence of possible values of +Y in the rest of the course we will + + align:start position:0% +Y in the rest of the course we will + + + align:start position:0% +Y in the rest of the course we will +often use the total expectation theorem + + align:start position:0% +often use the total expectation theorem + + + align:start position:0% +often use the total expectation theorem +including in cases where Y ranges over + + align:start position:0% +including in cases where Y ranges over + + + align:start position:0% +including in cases where Y ranges over +an infinite discrete set in fact we will + + align:start position:0% +an infinite discrete set in fact we will + + + align:start position:0% +an infinite discrete set in fact we will +see that this theorem is an extremely + + align:start position:0% +see that this theorem is an extremely + + + align:start position:0% +see that this theorem is an extremely +useful tool that can be used to divide + + align:start position:0% +useful tool that can be used to divide + + + align:start position:0% +useful tool that can be used to divide +and conquer complicated models \ No newline at end of file diff --git a/vYURcLuJEZs.txt b/vYURcLuJEZs.txt new file mode 100644 index 0000000000000000000000000000000000000000..42e8b2b4c406d810e79b9ab0def694a7c9ec8448 --- /dev/null +++ b/vYURcLuJEZs.txt @@ -0,0 +1,6736 @@ +align:start position:0% + +The following content is provided under + + align:start position:0% +The following content is provided under + + + align:start position:0% +The following content is provided under +a Creative Common License. Your support + + align:start position:0% +a Creative Common License. Your support + + + align:start position:0% +a Creative Common License. Your support +will help MIT Open Courseware continue + + align:start position:0% +will help MIT Open Courseware continue + + + align:start position:0% +will help MIT Open Courseware continue +to offer high-quality educational + + align:start position:0% +to offer high-quality educational + + + align:start position:0% +to offer high-quality educational +resources for free. To make a donation + + align:start position:0% +resources for free. To make a donation + + + align:start position:0% +resources for free. To make a donation +or view additional materials from + + align:start position:0% +or view additional materials from + + + align:start position:0% +or view additional materials from +hundreds of MIT courses, visit MIT Open + + align:start position:0% +hundreds of MIT courses, visit MIT Open + + + align:start position:0% +hundreds of MIT courses, visit MIT Open +Courseware at ocw.mmit.edu. + + align:start position:0% + + + + align:start position:0% + +Okay. Uh in this module we're going to + + align:start position:0% +Okay. Uh in this module we're going to + + + align:start position:0% +Okay. Uh in this module we're going to +talk about quality and uh uh let me just + + align:start position:0% +talk about quality and uh uh let me just + + + align:start position:0% +talk about quality and uh uh let me just +say that that you know the whole lean + + align:start position:0% +say that that you know the whole lean + + + align:start position:0% +say that that you know the whole lean +process doesn't work without quality and + + align:start position:0% +process doesn't work without quality and + + + align:start position:0% +process doesn't work without quality and +everybody thinks of quality you think of + + align:start position:0% +everybody thinks of quality you think of + + + align:start position:0% +everybody thinks of quality you think of +manufacturing. Okay. Uh let me suggest + + align:start position:0% +manufacturing. Okay. Uh let me suggest + + + align:start position:0% +manufacturing. Okay. Uh let me suggest +here that as we extended manufacturing + + align:start position:0% +here that as we extended manufacturing + + + align:start position:0% +here that as we extended manufacturing +to our suppliers, if the supplier ships + + align:start position:0% +to our suppliers, if the supplier ships + + + align:start position:0% +to our suppliers, if the supplier ships +incomplete, incorrect parts to us, u uh + + align:start position:0% +incomplete, incorrect parts to us, u uh + + + align:start position:0% +incomplete, incorrect parts to us, u uh +doesn't do us any good. I had F-15 + + align:start position:0% +doesn't do us any good. I had F-15 + + + align:start position:0% +doesn't do us any good. I had F-15 +composite assemblies coming in from + + align:start position:0% +composite assemblies coming in from + + + align:start position:0% +composite assemblies coming in from +Israel and they were stacking up and + + align:start position:0% +Israel and they were stacking up and + + + align:start position:0% +Israel and they were stacking up and +when I when I got there, uh it was + + align:start position:0% +when I when I got there, uh it was + + + align:start position:0% +when I when I got there, uh it was +before my time. I didn't start that line + + align:start position:0% +before my time. I didn't start that line + + + align:start position:0% +before my time. I didn't start that line +and they were shipping and getting paid + + align:start position:0% +and they were shipping and getting paid + + + align:start position:0% +and they were shipping and getting paid +for these composite sections on the F-15 + + align:start position:0% +for these composite sections on the F-15 + + + align:start position:0% +for these composite sections on the F-15 +and my guys were rejecting them because + + align:start position:0% +and my guys were rejecting them because + + + align:start position:0% +and my guys were rejecting them because +of voids or you know discrepancies and + + align:start position:0% +of voids or you know discrepancies and + + + align:start position:0% +of voids or you know discrepancies and +then we were trying to figure out how + + align:start position:0% +then we were trying to figure out how + + + align:start position:0% +then we were trying to figure out how +from an engineering standpoint to uh + + align:start position:0% +from an engineering standpoint to uh + + + align:start position:0% +from an engineering standpoint to uh +disposition those from a standpoint do + + align:start position:0% +disposition those from a standpoint do + + + align:start position:0% +disposition those from a standpoint do +we have to cut out the cut out the nom + + align:start position:0% +we have to cut out the cut out the nom + + + align:start position:0% +we have to cut out the cut out the nom +Nomx and put a patch on it and that kind + + align:start position:0% +Nomx and put a patch on it and that kind + + + align:start position:0% +Nomx and put a patch on it and that kind +of stuff. And I said wait a minute wait + + align:start position:0% +of stuff. And I said wait a minute wait + + + align:start position:0% +of stuff. And I said wait a minute wait +a minute this is wrong. You know, we + + align:start position:0% +a minute this is wrong. You know, we + + + align:start position:0% +a minute this is wrong. You know, we +want + + align:start position:0% +want + + + align:start position:0% +want +Israeli Aircraft Industries to make a + + align:start position:0% +Israeli Aircraft Industries to make a + + + align:start position:0% +Israeli Aircraft Industries to make a +perfect part to inspect it to get our + + align:start position:0% +perfect part to inspect it to get our + + + align:start position:0% +perfect part to inspect it to get our +acceptance on that part and ship a good + + align:start position:0% +acceptance on that part and ship a good + + + align:start position:0% +acceptance on that part and ship a good +part so I can put it right on top, you + + align:start position:0% +part so I can put it right on top, you + + + align:start position:0% +part so I can put it right on top, you +know, right in the in the assembly line. + + align:start position:0% +know, right in the in the assembly line. + + + align:start position:0% +know, right in the in the assembly line. +And so there's no way that you can + + align:start position:0% +And so there's no way that you can + + + align:start position:0% +And so there's no way that you can +achieve cycle time, can achieve manh + + align:start position:0% +achieve cycle time, can achieve manh + + + align:start position:0% +achieve cycle time, can achieve manh +hours and personnel hours. I'm gender + + align:start position:0% +hours and personnel hours. I'm gender + + + align:start position:0% +hours and personnel hours. I'm gender +center. See, I'm an old guy and when I + + align:start position:0% +center. See, I'm an old guy and when I + + + align:start position:0% +center. See, I'm an old guy and when I +started in this business, it was man + + align:start position:0% +started in this business, it was man + + + align:start position:0% +started in this business, it was man +hours. and now it's labor hours and uh + + align:start position:0% +hours. and now it's labor hours and uh + + + align:start position:0% +hours. and now it's labor hours and uh +so uh you can't achieve your unit cost + + align:start position:0% +so uh you can't achieve your unit cost + + + align:start position:0% +so uh you can't achieve your unit cost +uh or your schedule with bad quality and + + align:start position:0% +uh or your schedule with bad quality and + + + align:start position:0% +uh or your schedule with bad quality and +most people think of this kind of an + + align:start position:0% +most people think of this kind of an + + + align:start position:0% +most people think of this kind of an +example in terms of manufacturing and + + align:start position:0% +example in terms of manufacturing and + + + align:start position:0% +example in terms of manufacturing and +that kind of stuff now and I've just + + align:start position:0% +that kind of stuff now and I've just + + + align:start position:0% +that kind of stuff now and I've just +given you a manufacturing example in the + + align:start position:0% +given you a manufacturing example in the + + + align:start position:0% +given you a manufacturing example in the +factory and a supplier giving us bad + + align:start position:0% +factory and a supplier giving us bad + + + align:start position:0% +factory and a supplier giving us bad +parts but in engineering if we have + + align:start position:0% +parts but in engineering if we have + + + align:start position:0% +parts but in engineering if we have +incorrect drawings or we have mistakes + + align:start position:0% +incorrect drawings or we have mistakes + + + align:start position:0% +incorrect drawings or we have mistakes +on the drawing where the tolerances are + + align:start position:0% +on the drawing where the tolerances are + + + align:start position:0% +on the drawing where the tolerances are +wrong or we leave out a material call + + align:start position:0% +wrong or we leave out a material call + + + align:start position:0% +wrong or we leave out a material call +out or call out the wrong material spec + + align:start position:0% +out or call out the wrong material spec + + + align:start position:0% +out or call out the wrong material spec +or something like that. We send those + + align:start position:0% +or something like that. We send those + + + align:start position:0% +or something like that. We send those +drawings or the equivalent 3D solid + + align:start position:0% +drawings or the equivalent 3D solid + + + align:start position:0% +drawings or the equivalent 3D solid +um technical data out to the suppliers, + + align:start position:0% +um technical data out to the suppliers, + + + align:start position:0% +um technical data out to the suppliers, +they get it wrong, it comes in wrong or + + align:start position:0% +they get it wrong, it comes in wrong or + + + align:start position:0% +they get it wrong, it comes in wrong or +our factory builds it wrong. So of the + + align:start position:0% +our factory builds it wrong. So of the + + + align:start position:0% +our factory builds it wrong. So of the +of all the elements of achieving a lean + + align:start position:0% +of all the elements of achieving a lean + + + align:start position:0% +of all the elements of achieving a lean +enterprise quality is is you know + + align:start position:0% +enterprise quality is is you know + + + align:start position:0% +enterprise quality is is you know +critical and it's quality and accounting + + align:start position:0% +critical and it's quality and accounting + + + align:start position:0% +critical and it's quality and accounting +data quality and everything. Okay. So I + + align:start position:0% +data quality and everything. Okay. So I + + + align:start position:0% +data quality and everything. Okay. So I +mean I'll say this about 10 times and if + + align:start position:0% +mean I'll say this about 10 times and if + + + align:start position:0% +mean I'll say this about 10 times and if +you if you give me a a low mark for + + align:start position:0% +you if you give me a a low mark for + + + align:start position:0% +you if you give me a a low mark for +saying he's repetitive I'll take that + + align:start position:0% +saying he's repetitive I'll take that + + + align:start position:0% +saying he's repetitive I'll take that +because it's for emphasis. Okay. Very + + align:start position:0% +because it's for emphasis. Okay. Very + + + align:start position:0% +because it's for emphasis. Okay. Very +very important. So, we're going to + + align:start position:0% +very important. So, we're going to + + + align:start position:0% +very important. So, we're going to +talk about how quality is essential to + + align:start position:0% +talk about how quality is essential to + + + align:start position:0% +talk about how quality is essential to +achieving customer satisfaction. I don't + + align:start position:0% +achieving customer satisfaction. I don't + + + align:start position:0% +achieving customer satisfaction. I don't +want two cardboard boxes in the back of + + align:start position:0% +want two cardboard boxes in the back of + + + align:start position:0% +want two cardboard boxes in the back of +my brand new car that says take it to + + align:start position:0% +my brand new car that says take it to + + + align:start position:0% +my brand new car that says take it to +the dealer, you know, because we they + + align:start position:0% +the dealer, you know, because we they + + + align:start position:0% +the dealer, you know, because we they +delivered a car without 100% of the + + align:start position:0% +delivered a car without 100% of the + + + align:start position:0% +delivered a car without 100% of the +components in it. And that happens. + + align:start position:0% +components in it. And that happens. + + + align:start position:0% +components in it. And that happens. +We're going to talk about product + + align:start position:0% +We're going to talk about product + + + align:start position:0% +We're going to talk about product +quality and process quality. And the + + align:start position:0% +quality and process quality. And the + + + align:start position:0% +quality and process quality. And the +fact is it's very very difficult to get + + align:start position:0% +fact is it's very very difficult to get + + + align:start position:0% +fact is it's very very difficult to get +product quality without good processes. + + align:start position:0% +product quality without good processes. + + + align:start position:0% +product quality without good processes. +We're going to talk about the some tools + + align:start position:0% +We're going to talk about the some tools + + + align:start position:0% +We're going to talk about the some tools +and these are tools that you may not + + align:start position:0% +and these are tools that you may not + + + align:start position:0% +and these are tools that you may not +have been exposed to before and we're + + align:start position:0% +have been exposed to before and we're + + + align:start position:0% +have been exposed to before and we're +going to talk about you remember in the + + align:start position:0% +going to talk about you remember in the + + + align:start position:0% +going to talk about you remember in the +beginning Earl mentioned the fact that + + align:start position:0% +beginning Earl mentioned the fact that + + + align:start position:0% +beginning Earl mentioned the fact that +we've got lean and then we've got six + + align:start position:0% +we've got lean and then we've got six + + + align:start position:0% +we've got lean and then we've got six +sigma and industry basically now is + + align:start position:0% +sigma and industry basically now is + + + align:start position:0% +sigma and industry basically now is +talking about lean six sigma and u we're + + align:start position:0% +talking about lean six sigma and u we're + + + align:start position:0% +talking about lean six sigma and u we're +trying to achieve the customer + + align:start position:0% +trying to achieve the customer + + + align:start position:0% +trying to achieve the customer +satisfaction you there are there are + + align:start position:0% +satisfaction you there are there are + + + align:start position:0% +satisfaction you there are there are +people that are consultants now that are + + align:start position:0% +people that are consultants now that are + + + align:start position:0% +people that are consultants now that are +making + + align:start position:0% +making + + + align:start position:0% +making +their livelihood about saying, "Use our + + align:start position:0% +their livelihood about saying, "Use our + + + align:start position:0% +their livelihood about saying, "Use our +process and we're going to get an + + align:start position:0% +process and we're going to get an + + + align:start position:0% +process and we're going to get an +overjoyed customer." You know, that that + + align:start position:0% +overjoyed customer." You know, that that + + + align:start position:0% +overjoyed customer." You know, that that +kind of stuff, you know, deliriously + + align:start position:0% +kind of stuff, you know, deliriously + + + align:start position:0% +kind of stuff, you know, deliriously +happy customer. Well, that's what we + + align:start position:0% +happy customer. Well, that's what we + + + align:start position:0% +happy customer. Well, that's what we +want, too. I heard someone mention, + + align:start position:0% +want, too. I heard someone mention, + + + align:start position:0% +want, too. I heard someone mention, +maybe it's Mark or somebody before + + align:start position:0% +maybe it's Mark or somebody before + + + align:start position:0% +maybe it's Mark or somebody before +talking about the iceberg effect. This + + align:start position:0% +talking about the iceberg effect. This + + + align:start position:0% +talking about the iceberg effect. This +is a typical typical um drawing now + + align:start position:0% +is a typical typical um drawing now + + + align:start position:0% +is a typical typical um drawing now +because this is classically, you know, + + align:start position:0% +because this is classically, you know, + + + align:start position:0% +because this is classically, you know, +the Titanic didn't see this to the end. + + align:start position:0% +the Titanic didn't see this to the end. + + + align:start position:0% +the Titanic didn't see this to the end. +The problem what sunk the sunk the ship + + align:start position:0% +The problem what sunk the sunk the ship + + + align:start position:0% +The problem what sunk the sunk the ship +was this big hunk of the iceberg that + + align:start position:0% +was this big hunk of the iceberg that + + + align:start position:0% +was this big hunk of the iceberg that +was below the water and uh the stuff + + align:start position:0% +was below the water and uh the stuff + + + align:start position:0% +was below the water and uh the stuff +that we can measure uh very readily is + + align:start position:0% +that we can measure uh very readily is + + + align:start position:0% +that we can measure uh very readily is +scrap and rework service calls + + align:start position:0% +scrap and rework service calls + + + align:start position:0% +scrap and rework service calls +warranties scrap and rework I mean + + align:start position:0% +warranties scrap and rework I mean + + + align:start position:0% +warranties scrap and rework I mean +typically you can have 10% scrap and 15% + + align:start position:0% +typically you can have 10% scrap and 15% + + + align:start position:0% +typically you can have 10% scrap and 15% +rework in the old days that's 25% of the + + align:start position:0% +rework in the old days that's 25% of the + + + align:start position:0% +rework in the old days that's 25% of the +product cost the reason that Detroit + + align:start position:0% +product cost the reason that Detroit + + + align:start position:0% +product cost the reason that Detroit +can't compete with you know Honda and + + align:start position:0% +can't compete with you know Honda and + + + align:start position:0% +can't compete with you know Honda and +Nissan and and and uh uh Toyota is the + + align:start position:0% +Nissan and and and uh uh Toyota is the + + + align:start position:0% +Nissan and and and uh uh Toyota is the +fact is that we've got very high rates + + align:start position:0% +fact is that we've got very high rates + + + align:start position:0% +fact is that we've got very high rates +of this in the US. + + align:start position:0% +of this in the US. + + + align:start position:0% +of this in the US. +And so they can get a 25% cost advantage + + align:start position:0% +And so they can get a 25% cost advantage + + + align:start position:0% +And so they can get a 25% cost advantage +just by getting perfect quality. You + + align:start position:0% +just by getting perfect quality. You + + + align:start position:0% +just by getting perfect quality. You +remember yesterday I said Lexus's next + + align:start position:0% +remember yesterday I said Lexus's next + + + align:start position:0% +remember yesterday I said Lexus's next +time you see the the Lexus logo or on + + align:start position:0% +time you see the the Lexus logo or on + + + align:start position:0% +time you see the the Lexus logo or on +advertising uh on the on TV and all that + + align:start position:0% +advertising uh on the on TV and all that + + + align:start position:0% +advertising uh on the on TV and all that +Lexus the relentless pursuit of + + align:start position:0% +Lexus the relentless pursuit of + + + align:start position:0% +Lexus the relentless pursuit of +perfection. That means getting rid of + + align:start position:0% +perfection. That means getting rid of + + + align:start position:0% +perfection. That means getting rid of +this stuff. And that's a roughly a 20 + + align:start position:0% +this stuff. And that's a roughly a 20 + + + align:start position:0% +this stuff. And that's a roughly a 20 +25% cost advantage. And it helps us + + align:start position:0% +25% cost advantage. And it helps us + + + align:start position:0% +25% cost advantage. And it helps us +deliver a competitive product to our + + align:start position:0% +deliver a competitive product to our + + + align:start position:0% +deliver a competitive product to our +customers. Service calls, you know, that + + align:start position:0% +customers. Service calls, you know, that + + + align:start position:0% +customers. Service calls, you know, that +that's the may you know the old before + + align:start position:0% +that's the may you know the old before + + + align:start position:0% +that's the may you know the old before +your time, but in early days of + + align:start position:0% +your time, but in early days of + + + align:start position:0% +your time, but in early days of +television, there used to be an ad of a + + align:start position:0% +television, there used to be an ad of a + + + align:start position:0% +television, there used to be an ad of a +guy who just died recently, the May Tag + + align:start position:0% +guy who just died recently, the May Tag + + + align:start position:0% +guy who just died recently, the May Tag +repairmen, and he used to sit there and + + align:start position:0% +repairmen, and he used to sit there and + + + align:start position:0% +repairmen, and he used to sit there and +he was sitting there drinking drinking + + align:start position:0% +he was sitting there drinking drinking + + + align:start position:0% +he was sitting there drinking drinking +coffee and uh having a cigarette. And + + align:start position:0% +coffee and uh having a cigarette. And + + + align:start position:0% +coffee and uh having a cigarette. And +Mate used to say their quality was so + + align:start position:0% +Mate used to say their quality was so + + + align:start position:0% +Mate used to say their quality was so +good that our repairmen had nothing to + + align:start position:0% +good that our repairmen had nothing to + + + align:start position:0% +good that our repairmen had nothing to +do. Nobody ever called them because our + + align:start position:0% +do. Nobody ever called them because our + + + align:start position:0% +do. Nobody ever called them because our +washing machines and our dishwashers may + + align:start position:0% +washing machines and our dishwashers may + + + align:start position:0% +washing machines and our dishwashers may +tag is the quality. I mean that's a used + + align:start position:0% +tag is the quality. I mean that's a used + + + align:start position:0% +tag is the quality. I mean that's a used +to be a standard joke. But it turns out + + align:start position:0% +to be a standard joke. But it turns out + + + align:start position:0% +to be a standard joke. But it turns out +that that's what that a service call uh + + align:start position:0% +that that's what that a service call uh + + + align:start position:0% +that that's what that a service call uh +while on a brand new product, you know, + + align:start position:0% +while on a brand new product, you know, + + + align:start position:0% +while on a brand new product, you know, +uh is is waste and it makes unhappy + + align:start position:0% +uh is is waste and it makes unhappy + + + align:start position:0% +uh is is waste and it makes unhappy +customers because they're calling you + + align:start position:0% +customers because they're calling you + + + align:start position:0% +customers because they're calling you +because they have a problem. + + align:start position:0% +because they have a problem. + + + align:start position:0% +because they have a problem. +Typically, if it's under warranty, guess + + align:start position:0% +Typically, if it's under warranty, guess + + + align:start position:0% +Typically, if it's under warranty, guess +who pays for it? You know, we have to + + align:start position:0% +who pays for it? You know, we have to + + + align:start position:0% +who pays for it? You know, we have to +pay. So, we have to send somebody out to + + align:start position:0% +pay. So, we have to send somebody out to + + + align:start position:0% +pay. So, we have to send somebody out to +Fort Rucker to fix an Apache. It's on + + align:start position:0% +Fort Rucker to fix an Apache. It's on + + + align:start position:0% +Fort Rucker to fix an Apache. It's on +us. You know, that kind of stuff. So, + + align:start position:0% +us. You know, that kind of stuff. So, + + + align:start position:0% +us. You know, that kind of stuff. So, +that's not great. And then concessions. + + align:start position:0% +that's not great. And then concessions. + + + align:start position:0% +that's not great. And then concessions. +I mean, this is Boeing is going to wind + + align:start position:0% +I mean, this is Boeing is going to wind + + + align:start position:0% +I mean, this is Boeing is going to wind +up paying concessions to the airlines + + align:start position:0% +up paying concessions to the airlines + + + align:start position:0% +up paying concessions to the airlines +for being delivering late. Airbus is + + align:start position:0% +for being delivering late. Airbus is + + + align:start position:0% +for being delivering late. Airbus is +paying millions, hundreds of millions + + align:start position:0% +paying millions, hundreds of millions + + + align:start position:0% +paying millions, hundreds of millions +because the Airbus A380 is late. So, we + + align:start position:0% +because the Airbus A380 is late. So, we + + + align:start position:0% +because the Airbus A380 is late. So, we +don't, you know, and that's all poor + + align:start position:0% +don't, you know, and that's all poor + + + align:start position:0% +don't, you know, and that's all poor +quality. + + align:start position:0% +quality. + + + align:start position:0% +quality. +And then you've got excess inventory. I + + align:start position:0% +And then you've got excess inventory. I + + + align:start position:0% +And then you've got excess inventory. I +mean, we had a great example of that + + align:start position:0% +mean, we had a great example of that + + + align:start position:0% +mean, we had a great example of that +yesterday. You remember at the end of + + align:start position:0% +yesterday. You remember at the end of + + + align:start position:0% +yesterday. You remember at the end of +the round if you had it, you know, it + + align:start position:0% +the round if you had it, you know, it + + + align:start position:0% +the round if you had it, you know, it +comes off your bottom line. Overtime, + + align:start position:0% +comes off your bottom line. Overtime, + + + align:start position:0% +comes off your bottom line. Overtime, +boy. Oh, boy. I bet you they're spending + + align:start position:0% +boy. Oh, boy. I bet you they're spending + + + align:start position:0% +boy. Oh, boy. I bet you they're spending +millions in Seattle making sure the 787 + + align:start position:0% +millions in Seattle making sure the 787 + + + align:start position:0% +millions in Seattle making sure the 787 +is delivered as fast as they can and + + align:start position:0% +is delivered as fast as they can and + + + align:start position:0% +is delivered as fast as they can and +those guys are working seven day weeks. + + align:start position:0% +those guys are working seven day weeks. + + + align:start position:0% +those guys are working seven day weeks. +Seven day weeks. + + align:start position:0% +Seven day weeks. + + + align:start position:0% +Seven day weeks. +Absolutely. Nonvalue added steps. We + + align:start position:0% +Absolutely. Nonvalue added steps. We + + + align:start position:0% +Absolutely. Nonvalue added steps. We +talked about that cues and delays. I + + align:start position:0% +talked about that cues and delays. I + + + align:start position:0% +talked about that cues and delays. I +told you that classically everybody has + + align:start position:0% +told you that classically everybody has + + + align:start position:0% +told you that classically everybody has +tattooed on their arm. The biggest waste + + align:start position:0% +tattooed on their arm. The biggest waste + + + align:start position:0% +tattooed on their arm. The biggest waste +are move and queue. Moving stuff between + + align:start position:0% +are move and queue. Moving stuff between + + + align:start position:0% +are move and queue. Moving stuff between +machines and all that. You don't have to + + align:start position:0% +machines and all that. You don't have to + + + align:start position:0% +machines and all that. You don't have to +remember the the in in the athletic shoe + + align:start position:0% +remember the the in in the athletic shoe + + + align:start position:0% +remember the the in in the athletic shoe +department, the ladies were just moving + + align:start position:0% +department, the ladies were just moving + + + align:start position:0% +department, the ladies were just moving +that stuff between each other, you know, + + align:start position:0% +that stuff between each other, you know, + + + align:start position:0% +that stuff between each other, you know, +on on the production line there. + + align:start position:0% +on on the production line there. + + + align:start position:0% +on on the production line there. +One of the issues that came with the + + align:start position:0% +One of the issues that came with the + + + align:start position:0% +One of the issues that came with the +industrial revolution that I showed you + + align:start position:0% +industrial revolution that I showed you + + + align:start position:0% +industrial revolution that I showed you +on my very first chart um a couple of + + align:start position:0% +on my very first chart um a couple of + + + align:start position:0% +on my very first chart um a couple of +days ago was the fact is that that we + + align:start position:0% +days ago was the fact is that that we + + + align:start position:0% +days ago was the fact is that that we +went from the craft the master jeweler + + align:start position:0% +went from the craft the master jeweler + + + align:start position:0% +went from the craft the master jeweler +making the that he knew exactly how to + + align:start position:0% +making the that he knew exactly how to + + + align:start position:0% +making the that he knew exactly how to +build that watch to the mass production + + align:start position:0% +build that watch to the mass production + + + align:start position:0% +build that watch to the mass production +system Henry Ford and is the best + + align:start position:0% +system Henry Ford and is the best + + + align:start position:0% +system Henry Ford and is the best +example of it but other people did that + + align:start position:0% +example of it but other people did that + + + align:start position:0% +example of it but other people did that +where in fact we built something and + + align:start position:0% +where in fact we built something and + + + align:start position:0% +where in fact we built something and +then inspected it. The problem with that + + align:start position:0% +then inspected it. The problem with that + + + align:start position:0% +then inspected it. The problem with that +is the fact is that it's difficult. + + align:start position:0% +is the fact is that it's difficult. + + + align:start position:0% +is the fact is that it's difficult. +Inspection is subject to errors. How + + align:start position:0% +Inspection is subject to errors. How + + + align:start position:0% +Inspection is subject to errors. How +well trained is the inspection? How good + + align:start position:0% +well trained is the inspection? How good + + + align:start position:0% +well trained is the inspection? How good +is his inspection equipment? Um his + + align:start position:0% +is his inspection equipment? Um his + + + align:start position:0% +is his inspection equipment? Um his +measurement capability and then um you + + align:start position:0% +measurement capability and then um you + + + align:start position:0% +measurement capability and then um you +know is it you know is it a Monday + + align:start position:0% +know is it you know is it a Monday + + + align:start position:0% +know is it you know is it a Monday +morning and he had a tough weekend after + + align:start position:0% +morning and he had a tough weekend after + + + align:start position:0% +morning and he had a tough weekend after +a Super Bowl party? You know that kind + + align:start position:0% +a Super Bowl party? You know that kind + + + align:start position:0% +a Super Bowl party? You know that kind +of stuff. here. Uh, in your packet, + + align:start position:0% +of stuff. here. Uh, in your packet, + + + align:start position:0% +of stuff. here. Uh, in your packet, +there's a thing called F exercise. + + align:start position:0% +there's a thing called F exercise. + + + align:start position:0% +there's a thing called F exercise. +Everybody got Okay, great. Thanks. All + + align:start position:0% +Everybody got Okay, great. Thanks. All + + + align:start position:0% +Everybody got Okay, great. Thanks. All +right. What we're going to do, what + + align:start position:0% +right. What we're going to do, what + + + align:start position:0% +right. What we're going to do, what +we're going to do, let me just see if I + + align:start position:0% +we're going to do, let me just see if I + + + align:start position:0% +we're going to do, let me just see if I +can get + + align:start position:0% +can get + + + align:start position:0% +can get +We're going to time this exercise. We're + + align:start position:0% +We're going to time this exercise. We're + + + align:start position:0% +We're going to time this exercise. We're +big on stopwatches around here. Okay. + + align:start position:0% +big on stopwatches around here. Okay. + + + align:start position:0% +big on stopwatches around here. Okay. +And what I want you to do is to circle + + align:start position:0% +And what I want you to do is to circle + + + align:start position:0% +And what I want you to do is to circle +all the Fs. Look up here. The Fs or the + + align:start position:0% +all the Fs. Look up here. The Fs or the + + + align:start position:0% +all the Fs. Look up here. The Fs or the +capital Fs, okay? On the page. We're + + align:start position:0% +capital Fs, okay? On the page. We're + + + align:start position:0% +capital Fs, okay? On the page. We're +going to give you 30 seconds. And what + + align:start position:0% +going to give you 30 seconds. And what + + + align:start position:0% +going to give you 30 seconds. And what +we want you to do is to circle circle + + align:start position:0% +we want you to do is to circle circle + + + align:start position:0% +we want you to do is to circle circle +all those Fs and then count them, okay? + + align:start position:0% +all those Fs and then count them, okay? + + + align:start position:0% +all those Fs and then count them, okay? +And tell me how many how many that you + + align:start position:0% +And tell me how many how many that you + + + align:start position:0% +And tell me how many how many that you +found, okay? And uh when I say go, uh + + align:start position:0% +found, okay? And uh when I say go, uh + + + align:start position:0% +found, okay? And uh when I say go, uh +ready, set, go. + + align:start position:0% + + + + align:start position:0% + +Stop. Stop. Okay. All right. Um 13 to + + align:start position:0% +Stop. Stop. Okay. All right. Um 13 to + + + align:start position:0% +Stop. Stop. Okay. All right. Um 13 to +17. Yes. + + align:start position:0% +17. Yes. + + + align:start position:0% +17. Yes. +Nobody was 13 or 17. Again, this is not + + align:start position:0% +Nobody was 13 or 17. Again, this is not + + + align:start position:0% +Nobody was 13 or 17. Again, this is not +a test. Low numbers are part of the data + + align:start position:0% +a test. Low numbers are part of the data + + + align:start position:0% +a test. Low numbers are part of the data +collection process. 18 to 22. 18 to 22. + + align:start position:0% +collection process. 18 to 22. 18 to 22. + + + align:start position:0% +collection process. 18 to 22. 18 to 22. +One, two, three, four, four. Um, + + align:start position:0% +One, two, three, four, four. Um, + + + align:start position:0% +One, two, three, four, four. Um, +right there. There we go. Um, oh, do a + + align:start position:0% +right there. There we go. Um, oh, do a + + + align:start position:0% +right there. There we go. Um, oh, do a +bar, please. A bar. Yeah, + + align:start position:0% +bar, please. A bar. Yeah, + + + align:start position:0% +bar, please. A bar. Yeah, +um, 23 to 27. + + align:start position:0% +um, 23 to 27. + + + align:start position:0% +um, 23 to 27. +Whoa, lots of those. 1, two, three, + + align:start position:0% +Whoa, lots of those. 1, two, three, + + + align:start position:0% +Whoa, lots of those. 1, two, three, +four, five, six, seven, eight, 9, 10, + + align:start position:0% +four, five, six, seven, eight, 9, 10, + + + align:start position:0% +four, five, six, seven, eight, 9, 10, +11, 12, 13, 14, 15. My count's 15. + + align:start position:0% +11, 12, 13, 14, 15. My count's 15. + + + align:start position:0% +11, 12, 13, 14, 15. My count's 15. +15. Okay, that's off the chart. It's up + + align:start position:0% +15. Okay, that's off the chart. It's up + + + align:start position:0% +15. Okay, that's off the chart. It's up +here somewhere. Okay, 15 folks in that + + align:start position:0% +here somewhere. Okay, 15 folks in that + + + align:start position:0% +here somewhere. Okay, 15 folks in that +box. + + align:start position:0% +box. + + + align:start position:0% +box. +All righty. Um, 28 to 32. 28 to 32. One, + + align:start position:0% +All righty. Um, 28 to 32. 28 to 32. One, + + + align:start position:0% +All righty. Um, 28 to 32. 28 to 32. One, +two, three. All right, looks like we + + align:start position:0% +two, three. All right, looks like we + + + align:start position:0% +two, three. All right, looks like we +found our uh looks like we found our + + align:start position:0% +found our uh looks like we found our + + + align:start position:0% +found our uh looks like we found our +peak here. + + align:start position:0% +peak here. + + + align:start position:0% +peak here. +See, that first one was four. So, this + + align:start position:0% +See, that first one was four. So, this + + + align:start position:0% +See, that first one was four. So, this +was three. Lower. + + align:start position:0% +was three. Lower. + + + align:start position:0% +was three. Lower. +Higher. Um, there we go. + + align:start position:0% + + + + align:start position:0% + +And anybody get more than 33 or more? 33 + + align:start position:0% +And anybody get more than 33 or more? 33 + + + align:start position:0% +And anybody get more than 33 or more? 33 +or more? Nobody got 33 or more. I just + + align:start position:0% +or more? Nobody got 33 or more. I just + + + align:start position:0% +or more? Nobody got 33 or more. I just +went to get a calculator. You guys made + + align:start position:0% +went to get a calculator. You guys made + + + align:start position:0% +went to get a calculator. You guys made +my job easy. Well, let me show you. + + align:start position:0% +my job easy. Well, let me show you. + + + align:start position:0% +my job easy. Well, let me show you. +There they are. Do you know how many Fs + + align:start position:0% +There they are. Do you know how many Fs + + + align:start position:0% +There they are. Do you know how many Fs +there are? + + align:start position:0% +there are? + + + align:start position:0% +there are? + + align:start position:0% + + + align:start position:0% +36 Now the issue is the issue is that I + + align:start position:0% +36 Now the issue is the issue is that I + + + align:start position:0% +36 Now the issue is the issue is that I +mean I was going to calculate what + + align:start position:0% +mean I was going to calculate what + + + align:start position:0% +mean I was going to calculate what +percent of the class got the answer + + align:start position:0% +percent of the class got the answer + + + align:start position:0% +percent of the class got the answer +right or what percent of the class got + + align:start position:0% +right or what percent of the class got + + + align:start position:0% +right or what percent of the class got +that we now have a 100% of the class + + align:start position:0% +that we now have a 100% of the class + + + align:start position:0% +that we now have a 100% of the class +that got it wrong and the point is that + + align:start position:0% +that got it wrong and the point is that + + + align:start position:0% +that got it wrong and the point is that +all of + + align:start position:0% +all of + + + align:start position:0% +all of +you know all of this this area is I mean + + align:start position:0% +you know all of this this area is I mean + + + align:start position:0% +you know all of this this area is I mean +the the ones that we've missed are what + + align:start position:0% +the the ones that we've missed are what + + + align:start position:0% +the the ones that we've missed are what +we call in the business escapement ments + + align:start position:0% +we call in the business escapement ments + + + align:start position:0% +we call in the business escapement ments +escapements and it's a quality + + align:start position:0% +escapements and it's a quality + + + align:start position:0% +escapements and it's a quality +escapement. What does that mean? The + + align:start position:0% +escapement. What does that mean? The + + + align:start position:0% +escapement. What does that mean? The +whatever process that we put in place uh + + align:start position:0% +whatever process that we put in place uh + + + align:start position:0% +whatever process that we put in place uh +didn't catch the defect. Didn't catch + + align:start position:0% +didn't catch the defect. Didn't catch + + + align:start position:0% +didn't catch the defect. Didn't catch +the defect. I was at Mesa last week. I + + align:start position:0% +the defect. I was at Mesa last week. I + + + align:start position:0% +the defect. I was at Mesa last week. I +told you on this Ruden exercise and + + align:start position:0% +told you on this Ruden exercise and + + + align:start position:0% +told you on this Ruden exercise and +we're looking for voids using ultrasonic + + align:start position:0% +we're looking for voids using ultrasonic + + + align:start position:0% +we're looking for voids using ultrasonic +thermography and X-rays to catch voids + + align:start position:0% +thermography and X-rays to catch voids + + + align:start position:0% +thermography and X-rays to catch voids +in the Apache Attack helicopter block 3 + + align:start position:0% +in the Apache Attack helicopter block 3 + + + align:start position:0% +in the Apache Attack helicopter block 3 +improved aerodynamic rolblade. And the + + align:start position:0% +improved aerodynamic rolblade. And the + + + align:start position:0% +improved aerodynamic rolblade. And the +point is that we want a foolproof system + + align:start position:0% +point is that we want a foolproof system + + + align:start position:0% +point is that we want a foolproof system +to catch the errors. Why? Because in + + align:start position:0% +to catch the errors. Why? Because in + + + align:start position:0% +to catch the errors. Why? Because in +fact it won't, you know, it'll fatigue + + align:start position:0% +fact it won't, you know, it'll fatigue + + + align:start position:0% +fact it won't, you know, it'll fatigue +and you know we'll we'll kill a couple + + align:start position:0% +and you know we'll we'll kill a couple + + + align:start position:0% +and you know we'll we'll kill a couple +pilot a pilot and a co-pilot gunner + + align:start position:0% +pilot a pilot and a co-pilot gunner + + + align:start position:0% +pilot a pilot and a co-pilot gunner +can't do that. So we have to be good. + + align:start position:0% +can't do that. So we have to be good. + + + align:start position:0% +can't do that. So we have to be good. +Now the issue is that inspection + + align:start position:0% +Now the issue is that inspection + + + align:start position:0% +Now the issue is that inspection +inspection is costly and inspection is + + align:start position:0% +inspection is costly and inspection is + + + align:start position:0% +inspection is costly and inspection is +costly and in fact the the what has come + + align:start position:0% +costly and in fact the the what has come + + + align:start position:0% +costly and in fact the the what has come +out of the the the systems and all of + + align:start position:0% +out of the the the systems and all of + + + align:start position:0% +out of the the the systems and all of +our knowledge and experience now is that + + align:start position:0% +our knowledge and experience now is that + + + align:start position:0% +our knowledge and experience now is that +you cannot inspect listen to this now + + align:start position:0% +you cannot inspect listen to this now + + + align:start position:0% +you cannot inspect listen to this now +you cannot inspect quality into the + + align:start position:0% +you cannot inspect quality into the + + + align:start position:0% +you cannot inspect quality into the +product. You can't inspect it because + + align:start position:0% +product. You can't inspect it because + + + align:start position:0% +product. You can't inspect it because +even as we improve our inspection + + align:start position:0% +even as we improve our inspection + + + align:start position:0% +even as we improve our inspection +techniques you're going to miss + + align:start position:0% +techniques you're going to miss + + + align:start position:0% +techniques you're going to miss +something. And so all the things that + + align:start position:0% +something. And so all the things that + + + align:start position:0% +something. And so all the things that +we're trying to do in lean are to in + + align:start position:0% +we're trying to do in lean are to in + + + align:start position:0% +we're trying to do in lean are to in +fact foolproof Murphy proof the system + + align:start position:0% +fact foolproof Murphy proof the system + + + align:start position:0% +fact foolproof Murphy proof the system +so that the tools the design + + align:start position:0% +so that the tools the design + + + align:start position:0% +so that the tools the design +uh and the individual operators + + align:start position:0% +uh and the individual operators + + + align:start position:0% +uh and the individual operators +proficiency you remember I keep on + + align:start position:0% +proficiency you remember I keep on + + + align:start position:0% +proficiency you remember I keep on +saying that the the expert in the system + + align:start position:0% +saying that the the expert in the system + + + align:start position:0% +saying that the the expert in the system +is the person the guy or the gal that + + align:start position:0% +is the person the guy or the gal that + + + align:start position:0% +is the person the guy or the gal that +does the job every day. They know what's + + align:start position:0% +does the job every day. They know what's + + + align:start position:0% +does the job every day. They know what's +wrong and they can stop it and they have + + align:start position:0% +wrong and they can stop it and they have + + + align:start position:0% +wrong and they can stop it and they have +to stop it. If the if the workforce is + + align:start position:0% +to stop it. If the if the workforce is + + + align:start position:0% +to stop it. If the if the workforce is +not motivated and not trained, it's very + + align:start position:0% +not motivated and not trained, it's very + + + align:start position:0% +not motivated and not trained, it's very +very difficult. But we try upstream, you + + align:start position:0% +very difficult. But we try upstream, you + + + align:start position:0% +very difficult. But we try upstream, you +know, the smart engineers, the smart + + align:start position:0% +know, the smart engineers, the smart + + + align:start position:0% +know, the smart engineers, the smart +quality engineers that design the + + align:start position:0% +quality engineers that design the + + + align:start position:0% +quality engineers that design the +process system is to in fact make it so + + align:start position:0% +process system is to in fact make it so + + + align:start position:0% +process system is to in fact make it so +that we can't make a mistake. Earl + + align:start position:0% +that we can't make a mistake. Earl + + + align:start position:0% +that we can't make a mistake. Earl +showed you a chart the other day, the + + align:start position:0% +showed you a chart the other day, the + + + align:start position:0% +showed you a chart the other day, the +one that had the elephant on it. And + + align:start position:0% +one that had the elephant on it. And + + + align:start position:0% +one that had the elephant on it. And +then right after that, we we showed the + + align:start position:0% +then right after that, we we showed the + + + align:start position:0% +then right after that, we we showed the +ones where the the pieces cannot be + + align:start position:0% +ones where the the pieces cannot be + + + align:start position:0% +ones where the the pieces cannot be +installed incorrectly. And we use all + + align:start position:0% +installed incorrectly. And we use all + + + align:start position:0% +installed incorrectly. And we use all +sorts of techniques like, you know, an + + align:start position:0% +sorts of techniques like, you know, an + + + align:start position:0% +sorts of techniques like, you know, an +electrical, you know, a yellow wire with + + align:start position:0% +electrical, you know, a yellow wire with + + + align:start position:0% +electrical, you know, a yellow wire with +a yellow plug and we put it on like that + + align:start position:0% +a yellow plug and we put it on like that + + + align:start position:0% +a yellow plug and we put it on like that +or we we use a a great big fat lug and a + + align:start position:0% +or we we use a a great big fat lug and a + + + align:start position:0% +or we we use a a great big fat lug and a +big fat wire to fit on that lug and it + + align:start position:0% +big fat wire to fit on that lug and it + + + align:start position:0% +big fat wire to fit on that lug and it +the it won't fit on the other ones. We + + align:start position:0% +the it won't fit on the other ones. We + + + align:start position:0% +the it won't fit on the other ones. We +try to take all opportunities + + align:start position:0% +try to take all opportunities + + + align:start position:0% +try to take all opportunities +opportunities for errors out of the + + align:start position:0% +opportunities for errors out of the + + + align:start position:0% +opportunities for errors out of the +system. + + align:start position:0% +system. + + + align:start position:0% +system. +So + + align:start position:0% +So + + + align:start position:0% +So +anyway, we'll talk more about that. + + align:start position:0% +anyway, we'll talk more about that. + + + align:start position:0% +anyway, we'll talk more about that. +Terrific. + + align:start position:0% +Terrific. + + + align:start position:0% +Terrific. +Okay. Now, here's an interesting thing. + + align:start position:0% +Okay. Now, here's an interesting thing. + + + align:start position:0% +Okay. Now, here's an interesting thing. +Inspection and quality typically are 10% + + align:start position:0% +Inspection and quality typically are 10% + + + align:start position:0% +Inspection and quality typically are 10% +of the cost. I mean, we try to get it + + align:start position:0% +of the cost. I mean, we try to get it + + + align:start position:0% +of the cost. I mean, we try to get it +down to 10% of the cost and try to do + + align:start position:0% +down to 10% of the cost and try to do + + + align:start position:0% +down to 10% of the cost and try to do +better than that. So, quality is an + + align:start position:0% +better than that. So, quality is an + + + align:start position:0% +better than that. So, quality is an +expensive part of it. You remember I + + align:start position:0% +expensive part of it. You remember I + + + align:start position:0% +expensive part of it. You remember I +said scrap and we were could be 25%. + + align:start position:0% +said scrap and we were could be 25%. + + + align:start position:0% +said scrap and we were could be 25%. +We're trying to get that down to zero. + + align:start position:0% +We're trying to get that down to zero. + + + align:start position:0% +We're trying to get that down to zero. +We're trying to get our quality perfect. + + align:start position:0% +We're trying to get our quality perfect. + + + align:start position:0% +We're trying to get our quality perfect. +And + + align:start position:0% +And + + + align:start position:0% +And +it turns out that inspector efficiency + + align:start position:0% +it turns out that inspector efficiency + + + align:start position:0% +it turns out that inspector efficiency +if you look this way you know I was + + align:start position:0% +if you look this way you know I was + + + align:start position:0% +if you look this way you know I was +going to calculate your efficiency and + + align:start position:0% +going to calculate your efficiency and + + + align:start position:0% +going to calculate your efficiency and +say well we well actually if you do it + + align:start position:0% +say well we well actually if you do it + + + align:start position:0% +say well we well actually if you do it +by by f it's about 70%. Yeah probably + + align:start position:0% +by by f it's about 70%. Yeah probably + + + align:start position:0% +by by f it's about 70%. Yeah probably +about 70%. Yeah which is this red. + + align:start position:0% +about 70%. Yeah which is this red. + + + align:start position:0% +about 70%. Yeah which is this red. +So it turns out that it turns out that + + align:start position:0% +So it turns out that it turns out that + + + align:start position:0% +So it turns out that it turns out that +the name of the you know some people say + + align:start position:0% +the name of the you know some people say + + + align:start position:0% +the name of the you know some people say +well the quality is bad add more + + align:start position:0% +well the quality is bad add more + + + align:start position:0% +well the quality is bad add more +inspectors add more inspectors you know + + align:start position:0% +inspectors add more inspectors you know + + + align:start position:0% +inspectors add more inspectors you know +wrong. Okay I mean yeah you can in fact + + align:start position:0% +wrong. Okay I mean yeah you can in fact + + + align:start position:0% +wrong. Okay I mean yeah you can in fact +add + + align:start position:0% +add + + + align:start position:0% +add +multiple inspections or multiple + + align:start position:0% +multiple inspections or multiple + + + align:start position:0% +multiple inspections or multiple +inspectors to the to the point if we can + + align:start position:0% +inspectors to the to the point if we can + + + align:start position:0% +inspectors to the to the point if we can +get six sigma with 11 of these people in + + align:start position:0% +get six sigma with 11 of these people in + + + align:start position:0% +get six sigma with 11 of these people in +a row. Yeah but that is not 10% quality. + + align:start position:0% +a row. Yeah but that is not 10% quality. + + + align:start position:0% +a row. Yeah but that is not 10% quality. +You see the problem is that you can't + + align:start position:0% +You see the problem is that you can't + + + align:start position:0% +You see the problem is that you can't +you can't be competitive with very high + + align:start position:0% +you can't be competitive with very high + + + align:start position:0% +you can't be competitive with very high +amount. These are the escapements and + + align:start position:0% +amount. These are the escapements and + + + align:start position:0% +amount. These are the escapements and +and this is a new term maybe for you + + align:start position:0% +and this is a new term maybe for you + + + align:start position:0% +and this is a new term maybe for you +defects per million uh that is a + + align:start position:0% +defects per million uh that is a + + + align:start position:0% +defects per million uh that is a +technique for you know that is is used + + align:start position:0% +technique for you know that is is used + + + align:start position:0% +technique for you know that is is used +as a as a a parameter but the point is + + align:start position:0% +as a as a a parameter but the point is + + + align:start position:0% +as a as a a parameter but the point is +as you try to strive for perfection + + align:start position:0% +as you try to strive for perfection + + + align:start position:0% +as you try to strive for perfection +you're adding more and more quality + + align:start position:0% +you're adding more and more quality + + + align:start position:0% +you're adding more and more quality +personnel and it's the wrong way to go. + + align:start position:0% +personnel and it's the wrong way to go. + + + align:start position:0% +personnel and it's the wrong way to go. +We don't want to do that. We want to be + + align:start position:0% +We don't want to do that. We want to be + + + align:start position:0% +We don't want to do that. We want to be +able to make our inspection processes. + + align:start position:0% +able to make our inspection processes. + + + align:start position:0% +able to make our inspection processes. +And so this issue I was talking about + + align:start position:0% +And so this issue I was talking about + + + align:start position:0% +And so this issue I was talking about +yesterday or just before we were using a + + align:start position:0% +yesterday or just before we were using a + + + align:start position:0% +yesterday or just before we were using a +artificial intelligence system + + align:start position:0% +artificial intelligence system + + + align:start position:0% +artificial intelligence system +artificial intelligence system which in + + align:start position:0% +artificial intelligence system which in + + + align:start position:0% +artificial intelligence system which in +a new technique called thermography + + align:start position:0% +a new technique called thermography + + + align:start position:0% +a new technique called thermography +which was in fact scanning scanning the + + align:start position:0% +which was in fact scanning scanning the + + + align:start position:0% +which was in fact scanning scanning the +rotolades for voids and defects by using + + align:start position:0% +rotolades for voids and defects by using + + + align:start position:0% +rotolades for voids and defects by using +a bright strobe light that in fact + + align:start position:0% +a bright strobe light that in fact + + + align:start position:0% +a bright strobe light that in fact +created a slight amount of heat on the + + align:start position:0% +created a slight amount of heat on the + + + align:start position:0% +created a slight amount of heat on the +surface of the part. So that if there + + align:start position:0% +surface of the part. So that if there + + + align:start position:0% +surface of the part. So that if there +was a void, there would be a a delta t + + align:start position:0% +was a void, there would be a a delta t + + + align:start position:0% +was a void, there would be a a delta t +where the void was compared to the the + + align:start position:0% +where the void was compared to the the + + + align:start position:0% +where the void was compared to the the +basic rotor blade and that it took a a + + align:start position:0% +basic rotor blade and that it took a a + + + align:start position:0% +basic rotor blade and that it took a a +thermog a a infrared picture of that and + + align:start position:0% +thermog a a infrared picture of that and + + + align:start position:0% +thermog a a infrared picture of that and +we could detect the voids and we were + + align:start position:0% +we could detect the voids and we were + + + align:start position:0% +we could detect the voids and we were +developing software to be able to read + + align:start position:0% +developing software to be able to read + + + align:start position:0% +developing software to be able to read +that and say that void does not meet our + + align:start position:0% +that and say that void does not meet our + + + align:start position:0% +that and say that void does not meet our +spec. it's greater than a quarter inch + + align:start position:0% +spec. it's greater than a quarter inch + + + align:start position:0% +spec. it's greater than a quarter inch +or something like that and whatever the + + align:start position:0% +or something like that and whatever the + + + align:start position:0% +or something like that and whatever the +we're going to talk about upper and + + align:start position:0% +we're going to talk about upper and + + + align:start position:0% +we're going to talk about upper and +lower control limits for those kinds of + + align:start position:0% +lower control limits for those kinds of + + + align:start position:0% +lower control limits for those kinds of +things but we would like to be able to + + align:start position:0% +things but we would like to be able to + + + align:start position:0% +things but we would like to be able to +automate it because we can't depend on + + align:start position:0% +automate it because we can't depend on + + + align:start position:0% +automate it because we can't depend on +people pure inspection to do that. So + + align:start position:0% +people pure inspection to do that. So + + + align:start position:0% +people pure inspection to do that. So +this is this is tough stuff. Tough stuff + + align:start position:0% +this is this is tough stuff. Tough stuff + + + align:start position:0% +this is this is tough stuff. Tough stuff +when we're making very complex products + + align:start position:0% +when we're making very complex products + + + align:start position:0% +when we're making very complex products +that you folks are going to be working + + align:start position:0% +that you folks are going to be working + + + align:start position:0% +that you folks are going to be working +on whether it's you know computers or + + align:start position:0% +on whether it's you know computers or + + + align:start position:0% +on whether it's you know computers or +automobiles or airplanes or rockets or + + align:start position:0% +automobiles or airplanes or rockets or + + + align:start position:0% +automobiles or airplanes or rockets or +spacecraft. Diamond this stuff is tough. + + align:start position:0% +spacecraft. Diamond this stuff is tough. + + + align:start position:0% +spacecraft. Diamond this stuff is tough. +We talk about NASA talks about man- + + align:start position:0% +We talk about NASA talks about man- + + + align:start position:0% +We talk about NASA talks about man- +rated that means you know somebody's + + align:start position:0% +rated that means you know somebody's + + + align:start position:0% +rated that means you know somebody's +life is at stake and um so we have to be + + align:start position:0% +life is at stake and um so we have to be + + + align:start position:0% +life is at stake and um so we have to be +good. Okay. So, + + align:start position:0% + + + + align:start position:0% + +conformance to this to the spec and to + + align:start position:0% +conformance to this to the spec and to + + + align:start position:0% +conformance to this to the spec and to +our tolerance band for acceptable + + align:start position:0% +our tolerance band for acceptable + + + align:start position:0% +our tolerance band for acceptable +quality. Now, when I say acceptable + + align:start position:0% +quality. Now, when I say acceptable + + + align:start position:0% +quality. Now, when I say acceptable +quality, I'll tell you about a you know, + + align:start position:0% +quality, I'll tell you about a you know, + + + align:start position:0% +quality, I'll tell you about a you know, +we talk about machine parts plus or + + align:start position:0% +we talk about machine parts plus or + + + align:start position:0% +we talk about machine parts plus or +minus 15,000. That's a a normal kind of + + align:start position:0% +minus 15,000. That's a a normal kind of + + + align:start position:0% +minus 15,000. That's a a normal kind of +a a tolerance band. And uh and we're + + align:start position:0% +a a tolerance band. And uh and we're + + + align:start position:0% +a a tolerance band. And uh and we're +going to talk about process capability + + align:start position:0% +going to talk about process capability + + + align:start position:0% +going to talk about process capability +here pretty soon. And uh but sometimes + + align:start position:0% +here pretty soon. And uh but sometimes + + + align:start position:0% +here pretty soon. And uh but sometimes +the processes are are very very smaller + + align:start position:0% +the processes are are very very smaller + + + align:start position:0% +the processes are are very very smaller +than that. I used to make 60 M242 guns a + + align:start position:0% +than that. I used to make 60 M242 guns a + + + align:start position:0% +than that. I used to make 60 M242 guns a +month for the for the Bradley fighting + + align:start position:0% +month for the for the Bradley fighting + + + align:start position:0% +month for the for the Bradley fighting +vehicle for the uh M242 chain gun. The + + align:start position:0% +vehicle for the uh M242 chain gun. The + + + align:start position:0% +vehicle for the uh M242 chain gun. The +chain gun fired 600 rounds a minute, 10 + + align:start position:0% +chain gun fired 600 rounds a minute, 10 + + + align:start position:0% +chain gun fired 600 rounds a minute, 10 +a second. Those moving parts were + + align:start position:0% +a second. Those moving parts were + + + align:start position:0% +a second. Those moving parts were +zooming and there the the the the spec + + align:start position:0% +zooming and there the the the the spec + + + align:start position:0% +zooming and there the the the the spec +on those parts, the tolerance on that + + align:start position:0% +on those parts, the tolerance on that + + + align:start position:0% +on those parts, the tolerance on that +was 210,000 of an inch. 210,000 of an + + align:start position:0% +was 210,000 of an inch. 210,000 of an + + + align:start position:0% +was 210,000 of an inch. 210,000 of an +inch. And my friends at Prattton + + align:start position:0% +inch. And my friends at Prattton + + + align:start position:0% +inch. And my friends at Prattton +Whitney, I mean, they can relate to + + align:start position:0% +Whitney, I mean, they can relate to + + + align:start position:0% +Whitney, I mean, they can relate to +20,000 RPM uh uh rotors and compressors + + align:start position:0% +20,000 RPM uh uh rotors and compressors + + + align:start position:0% +20,000 RPM uh uh rotors and compressors +and stuff like that. And the tolerances + + align:start position:0% +and stuff like that. And the tolerances + + + align:start position:0% +and stuff like that. And the tolerances +are very very small when you're talking + + align:start position:0% +are very very small when you're talking + + + align:start position:0% +are very very small when you're talking +about that much. And they and while + + align:start position:0% +about that much. And they and while + + + align:start position:0% +about that much. And they and while +we're on that subject, you just not you + + align:start position:0% +we're on that subject, you just not you + + + align:start position:0% +we're on that subject, you just not you +cannot just take any old machine and get + + align:start position:0% +cannot just take any old machine and get + + + align:start position:0% +cannot just take any old machine and get +that kind of capability. And so we're + + align:start position:0% +that kind of capability. And so we're + + + align:start position:0% +that kind of capability. And so we're +going to have to match the machine to + + align:start position:0% +going to have to match the machine to + + + align:start position:0% +going to have to match the machine to +the process requirements we have because + + align:start position:0% +the process requirements we have because + + + align:start position:0% +the process requirements we have because +you just can't put it at vendor A or + + align:start position:0% +you just can't put it at vendor A or + + + align:start position:0% +you just can't put it at vendor A or +vendor B because they may not have a + + align:start position:0% +vendor B because they may not have a + + + align:start position:0% +vendor B because they may not have a +machine that can do that or we may not + + align:start position:0% +machine that can do that or we may not + + + align:start position:0% +machine that can do that or we may not +have a machine. We have to go find + + align:start position:0% +have a machine. We have to go find + + + align:start position:0% +have a machine. We have to go find +somebody can do that stuff. So engineers + + align:start position:0% +somebody can do that stuff. So engineers + + + align:start position:0% +somebody can do that stuff. So engineers +have got to be sensitive this. + + align:start position:0% +have got to be sensitive this. + + + align:start position:0% +have got to be sensitive this. +So we're talking about upper and lower + + align:start position:0% +So we're talking about upper and lower + + + align:start position:0% +So we're talking about upper and lower +control limits or upper and lower + + align:start position:0% +control limits or upper and lower + + + align:start position:0% +control limits or upper and lower +specification limit. So when I said plus + + align:start position:0% +specification limit. So when I said plus + + + align:start position:0% +specification limit. So when I said plus +or minus upper spec limit, lower spec + + align:start position:0% +or minus upper spec limit, lower spec + + + align:start position:0% +or minus upper spec limit, lower spec +limit, plus or minus 15,000s, that would + + align:start position:0% +limit, plus or minus 15,000s, that would + + + align:start position:0% +limit, plus or minus 15,000s, that would +be what we're trying to control to. And + + align:start position:0% +be what we're trying to control to. And + + + align:start position:0% +be what we're trying to control to. And +we're going to talk about control + + align:start position:0% +we're going to talk about control + + + align:start position:0% +we're going to talk about control +charts. Process quality is a measure of + + align:start position:0% +charts. Process quality is a measure of + + + align:start position:0% +charts. Process quality is a measure of +the capability to be able to produce it. + + align:start position:0% +the capability to be able to produce it. + + + align:start position:0% +the capability to be able to produce it. +When we want very very precise holes, we + + align:start position:0% +When we want very very precise holes, we + + + align:start position:0% +When we want very very precise holes, we +use a a machine called a jig boring + + align:start position:0% +use a a machine called a jig boring + + + align:start position:0% +use a a machine called a jig boring +machine. And they're made in Switzerland + + align:start position:0% +machine. And they're made in Switzerland + + + align:start position:0% +machine. And they're made in Switzerland +quite often. And they make the best + + align:start position:0% +quite often. And they make the best + + + align:start position:0% +quite often. And they make the best +machines. And you can you can drill very + + align:start position:0% +machines. And you can you can drill very + + + align:start position:0% +machines. And you can you can drill very +very precise holes. You just can't take + + align:start position:0% +very precise holes. You just can't take + + + align:start position:0% +very precise holes. You just can't take +you know the Sears Robuck uh drill press + + align:start position:0% +you know the Sears Robuck uh drill press + + + align:start position:0% +you know the Sears Robuck uh drill press +and get that kind of uh dimensional + + align:start position:0% +and get that kind of uh dimensional + + + align:start position:0% +and get that kind of uh dimensional +quality. Okay. So, how can we assure + + align:start position:0% +quality. Okay. So, how can we assure + + + align:start position:0% +quality. Okay. So, how can we assure +process quality and we're going to talk + + align:start position:0% +process quality and we're going to talk + + + align:start position:0% +process quality and we're going to talk +about some of that. So, there's a series + + align:start position:0% +about some of that. So, there's a series + + + align:start position:0% +about some of that. So, there's a series +of tools there's a series of tools that + + align:start position:0% +of tools there's a series of tools that + + + align:start position:0% +of tools there's a series of tools that +we use in the quality business. + + align:start position:0% +we use in the quality business. + + + align:start position:0% +we use in the quality business. +Flowcharts you've seen that now what + + align:start position:0% +Flowcharts you've seen that now what + + + align:start position:0% +Flowcharts you've seen that now what +basically do is take a flowchart and say + + align:start position:0% +basically do is take a flowchart and say + + + align:start position:0% +basically do is take a flowchart and say +what are all the processes to build our + + align:start position:0% +what are all the processes to build our + + + align:start position:0% +what are all the processes to build our +part. And we used to kit around at the, + + align:start position:0% +part. And we used to kit around at the, + + + align:start position:0% +part. And we used to kit around at the, +you know, when we talk about a + + align:start position:0% +you know, when we talk about a + + + align:start position:0% +you know, when we talk about a +flowchart, mill, drill, tap, and scrap. + + align:start position:0% +flowchart, mill, drill, tap, and scrap. + + + align:start position:0% +flowchart, mill, drill, tap, and scrap. +Now, how's that? Mill it, drill it, tap + + align:start position:0% +Now, how's that? Mill it, drill it, tap + + + align:start position:0% +Now, how's that? Mill it, drill it, tap +it, and then, gee, we didn't make the, + + align:start position:0% +it, and then, gee, we didn't make the, + + + align:start position:0% +it, and then, gee, we didn't make the, +we didn't make the the spec, so we scrap + + align:start position:0% +we didn't make the the spec, so we scrap + + + align:start position:0% +we didn't make the the spec, so we scrap +it, you know, mill, drill, tap, and + + align:start position:0% +it, you know, mill, drill, tap, and + + + align:start position:0% +it, you know, mill, drill, tap, and +scrap. But a flowchart is exactly what + + align:start position:0% +scrap. But a flowchart is exactly what + + + align:start position:0% +scrap. But a flowchart is exactly what +we did the other day, uh, when we were + + align:start position:0% +we did the other day, uh, when we were + + + align:start position:0% +we did the other day, uh, when we were +talking about, you know, uh, building + + align:start position:0% +talking about, you know, uh, building + + + align:start position:0% +talking about, you know, uh, building +airplanes. + + align:start position:0% +airplanes. + + + align:start position:0% +airplanes. +But we do that because of the fact that + + align:start position:0% +But we do that because of the fact that + + + align:start position:0% +But we do that because of the fact that +the quality engineers and incidentally + + align:start position:0% +the quality engineers and incidentally + + + align:start position:0% +the quality engineers and incidentally +that's another whole brand of quality + + align:start position:0% +that's another whole brand of quality + + + align:start position:0% +that's another whole brand of quality +type of engineers that we have aerero + + align:start position:0% +type of engineers that we have aerero + + + align:start position:0% +type of engineers that we have aerero +engineers and chem engineers and civil + + align:start position:0% +engineers and chem engineers and civil + + + align:start position:0% +engineers and chem engineers and civil +engineers but there's a thing called + + align:start position:0% +engineers but there's a thing called + + + align:start position:0% +engineers but there's a thing called +quality engineers and these folks are + + align:start position:0% +quality engineers and these folks are + + + align:start position:0% +quality engineers and these folks are +real engineers that in fact help us work + + align:start position:0% +real engineers that in fact help us work + + + align:start position:0% +real engineers that in fact help us work +on these uh uh and so we lay out the + + align:start position:0% +on these uh uh and so we lay out the + + + align:start position:0% +on these uh uh and so we lay out the +sequence the manufacturing engineers lay + + align:start position:0% +sequence the manufacturing engineers lay + + + align:start position:0% +sequence the manufacturing engineers lay +out the sequence of all the the + + align:start position:0% +out the sequence of all the the + + + align:start position:0% +out the sequence of all the the +flowchart on how we're going to mill it + + align:start position:0% +flowchart on how we're going to mill it + + + align:start position:0% +flowchart on how we're going to mill it +drill it heat uh rough machine stress + + align:start position:0% +drill it heat uh rough machine stress + + + align:start position:0% +drill it heat uh rough machine stress +relieve finish machine you grind, those + + align:start position:0% +relieve finish machine you grind, those + + + align:start position:0% +relieve finish machine you grind, those +kinds of things. And then we have check + + align:start position:0% +kinds of things. And then we have check + + + align:start position:0% +kinds of things. And then we have check +sheets. And in each operation, if it's a + + align:start position:0% +sheets. And in each operation, if it's a + + + align:start position:0% +sheets. And in each operation, if it's a +heat treating operation, we have a check + + align:start position:0% +heat treating operation, we have a check + + + align:start position:0% +heat treating operation, we have a check +sheet that says, make sure that the oven + + align:start position:0% +sheet that says, make sure that the oven + + + align:start position:0% +sheet that says, make sure that the oven +is up to 350°. Make sure that the tool + + align:start position:0% +is up to 350°. Make sure that the tool + + + align:start position:0% +is up to 350°. Make sure that the tool +is in the proper place. So, we have a + + align:start position:0% +is in the proper place. So, we have a + + + align:start position:0% +is in the proper place. So, we have a +check sheet to make sure that the + + align:start position:0% +check sheet to make sure that the + + + align:start position:0% +check sheet to make sure that the +employees follow the process. This is a + + align:start position:0% +employees follow the process. This is a + + + align:start position:0% +employees follow the process. This is a +histogram, a histogram of the data. Lean + + align:start position:0% +histogram, a histogram of the data. Lean + + + align:start position:0% +histogram, a histogram of the data. Lean +is a data-driven exercise. And we always + + align:start position:0% +is a data-driven exercise. And we always + + + align:start position:0% +is a data-driven exercise. And we always +collect data. No more opinions, get me + + align:start position:0% +collect data. No more opinions, get me + + + align:start position:0% +collect data. No more opinions, get me +the data kind of thing. Okay, so that's + + align:start position:0% +the data kind of thing. Okay, so that's + + + align:start position:0% +the data kind of thing. Okay, so that's +a tool. A Pareto chart, it looks like a + + align:start position:0% +a tool. A Pareto chart, it looks like a + + + align:start position:0% +a tool. A Pareto chart, it looks like a +histogram except that a Pareto chart + + align:start position:0% +histogram except that a Pareto chart + + + align:start position:0% +histogram except that a Pareto chart +basically plots the biggest and then the + + align:start position:0% +basically plots the biggest and then the + + + align:start position:0% +basically plots the biggest and then the +next biggest and all the way down to the + + align:start position:0% +next biggest and all the way down to the + + + align:start position:0% +next biggest and all the way down to the +bottom because we want to be able in our + + align:start position:0% +bottom because we want to be able in our + + + align:start position:0% +bottom because we want to be able in our +business find the kinds of errors and + + align:start position:0% +business find the kinds of errors and + + + align:start position:0% +business find the kinds of errors and +work on the biggest ones first because + + align:start position:0% +work on the biggest ones first because + + + align:start position:0% +work on the biggest ones first because +we don't have unlimited resources. Okay, + + align:start position:0% +we don't have unlimited resources. Okay, + + + align:start position:0% +we don't have unlimited resources. Okay, +so we won't spend a lot of time on that. + + align:start position:0% +so we won't spend a lot of time on that. + + + align:start position:0% +so we won't spend a lot of time on that. +So here's a fun exercise. These are your + + align:start position:0% +So here's a fun exercise. These are your + + + align:start position:0% +So here's a fun exercise. These are your +dessert for lunch. Okay, open up the + + align:start position:0% +dessert for lunch. Okay, open up the + + + align:start position:0% +dessert for lunch. Okay, open up the +bag. Please don't eat them. You want to + + align:start position:0% +bag. Please don't eat them. You want to + + + align:start position:0% +bag. Please don't eat them. You want to +get the sheet out? Yeah. Get Get there's + + align:start position:0% +get the sheet out? Yeah. Get Get there's + + + align:start position:0% +get the sheet out? Yeah. Get Get there's +a a sheet that looks like this. It says + + align:start position:0% +a a sheet that looks like this. It says + + + align:start position:0% +a a sheet that looks like this. It says +blank a blank Pareto chart. Blank PTO + + align:start position:0% +blank a blank Pareto chart. Blank PTO + + + align:start position:0% +blank a blank Pareto chart. Blank PTO +chart. Now uh if everybody's everybody's + + align:start position:0% +chart. Now uh if everybody's everybody's + + + align:start position:0% +chart. Now uh if everybody's everybody's +got their Pareto chart blank. Um uh what + + align:start position:0% +got their Pareto chart blank. Um uh what + + + align:start position:0% +got their Pareto chart blank. Um uh what +I want you to do now don't I want you to + + align:start position:0% +I want you to do now don't I want you to + + + align:start position:0% +I want you to do now don't I want you to +open them and put them right in front of + + align:start position:0% +open them and put them right in front of + + + align:start position:0% +open them and put them right in front of +you and I want you to count them. Okay? + + align:start position:0% +you and I want you to count them. Okay? + + + align:start position:0% +you and I want you to count them. Okay? +Count them the total number of each of + + align:start position:0% +Count them the total number of each of + + + align:start position:0% +Count them the total number of each of +you count them. And up in the corner up + + align:start position:0% +you count them. And up in the corner up + + + align:start position:0% +you count them. And up in the corner up +in the corner of your chart, up in the + + align:start position:0% +in the corner of your chart, up in the + + + align:start position:0% +in the corner of your chart, up in the +top corner of the chart, just tell me + + align:start position:0% +top corner of the chart, just tell me + + + align:start position:0% +top corner of the chart, just tell me +how many you've counted. + + align:start position:0% + + + + align:start position:0% + +You can eat the half. Don't don't count + + align:start position:0% +You can eat the half. Don't don't count + + + align:start position:0% +You can eat the half. Don't don't count +the broken ones. You can eat you can eat + + align:start position:0% +the broken ones. You can eat you can eat + + + align:start position:0% +the broken ones. You can eat you can eat +the broken one and don't break anymore. + + align:start position:0% +the broken one and don't break anymore. + + + align:start position:0% +the broken one and don't break anymore. +The next step, if you The first thing + + align:start position:0% +The next step, if you The first thing + + + align:start position:0% +The next step, if you The first thing +was to count the total. The second step + + align:start position:0% +was to count the total. The second step + + + align:start position:0% +was to count the total. The second step +I want you to do is to sort the colors. + + align:start position:0% +I want you to do is to sort the colors. + + + align:start position:0% +I want you to do is to sort the colors. +How many reds? How many oranges? How + + align:start position:0% +How many reds? How many oranges? How + + + align:start position:0% +How many reds? How many oranges? How +many browns? How many greens, etc. + + align:start position:0% +many browns? How many greens, etc. + + + align:start position:0% +many browns? How many greens, etc. +Well, no. It says right here. Yeah. + + align:start position:0% +Well, no. It says right here. Yeah. + + + align:start position:0% +Well, no. It says right here. Yeah. +How we doing on numbers? Absolute + + align:start position:0% +How we doing on numbers? Absolute + + + align:start position:0% +How we doing on numbers? Absolute +number. Does everybody get the numbers + + align:start position:0% +number. Does everybody get the numbers + + + align:start position:0% +number. Does everybody get the numbers +down? Okay. So, we're going to start + + align:start position:0% +down? Okay. So, we're going to start + + + align:start position:0% +down? Okay. So, we're going to start +right here. How many numbers did you How + + align:start position:0% +right here. How many numbers did you How + + + align:start position:0% +right here. How many numbers did you How +many5? + + align:start position:0% +many5? + + + align:start position:0% +many5? +Let's just Let's just do it on mass. How + + align:start position:0% +Let's just Let's just do it on mass. How + + + align:start position:0% +Let's just Let's just do it on mass. How +many you got? 55. 55. Who else got 55? + + align:start position:0% +many you got? 55. 55. Who else got 55? + + + align:start position:0% +many you got? 55. 55. Who else got 55? +One, two, three, four, five. 55s. + + align:start position:0% +One, two, three, four, five. 55s. + + + align:start position:0% +One, two, three, four, five. 55s. +56. + + align:start position:0% +56. + + + align:start position:0% +56. +Two, three 56s. + + align:start position:0% +Two, three 56s. + + + align:start position:0% +Two, three 56s. +54. 57. + + align:start position:0% +54. 57. + + + align:start position:0% +54. 57. +54. + + align:start position:0% +54. + + + align:start position:0% +54. +Two 57. + + align:start position:0% +Two 57. + + + align:start position:0% +Two 57. +Yeah. Okay. We'll go the other way. 257. + + align:start position:0% +Yeah. Okay. We'll go the other way. 257. + + + align:start position:0% +Yeah. Okay. We'll go the other way. 257. +We're just kind of letting this run out. + + align:start position:0% +We're just kind of letting this run out. + + + align:start position:0% +We're just kind of letting this run out. +58. The 158. + + align:start position:0% +58. The 158. + + + align:start position:0% +58. The 158. +Okay. Uh, looks like we're biased in the + + align:start position:0% +Okay. Uh, looks like we're biased in the + + + align:start position:0% +Okay. Uh, looks like we're biased in the +other direction. 54. + + align:start position:0% +other direction. 54. + + + align:start position:0% +other direction. 54. +Two. Three. This is a spread. 54. Wait, + + align:start position:0% +Two. Three. This is a spread. 54. Wait, + + + align:start position:0% +Two. Three. This is a spread. 54. Wait, +more + + align:start position:0% +more + + + align:start position:0% +more +two more. 54 is 53. + + align:start position:0% +two more. 54 is 53. + + + align:start position:0% +two more. 54 is 53. +15 253. + + align:start position:0% +15 253. + + + align:start position:0% +15 253. +Okay. And that's it. 60. Whoa. Never + + align:start position:0% +Okay. And that's it. 60. Whoa. Never + + + align:start position:0% +Okay. And that's it. 60. Whoa. Never +seen Never seen any other high lows. 30 + + align:start position:0% +seen Never seen any other high lows. 30 + + + align:start position:0% +seen Never seen any other high lows. 30 +times doing it. Never seen. Yeah. This + + align:start position:0% +times doing it. Never seen. Yeah. This + + + align:start position:0% +times doing it. Never seen. Yeah. This +is This is interesting. This is the + + align:start position:0% +is This is interesting. This is the + + + align:start position:0% +is This is interesting. This is the +highest ever. I think Eminem's process + + align:start position:0% +highest ever. I think Eminem's process + + + align:start position:0% +highest ever. I think Eminem's process +controls. + + align:start position:0% +controls. + + + align:start position:0% +controls. +This is this is the biggest spread we've + + align:start position:0% +This is this is the biggest spread we've + + + align:start position:0% +This is this is the biggest spread we've +ever seen by quite a bit. So you learn + + align:start position:0% +ever seen by quite a bit. So you learn + + + align:start position:0% +ever seen by quite a bit. So you learn +things from + + align:start position:0% +things from + + + align:start position:0% +things from +Okay. So we're 53 + + align:start position:0% +Okay. So we're 53 + + + align:start position:0% +Okay. So we're 53 +6 7 8 9 + + align:start position:0% + + + + align:start position:0% + +is five. + + align:start position:0% + + + + align:start position:0% + +One of the lessons here is that this + + align:start position:0% +One of the lessons here is that this + + + align:start position:0% +One of the lessons here is that this +doesn't have to be complicated, right? + + align:start position:0% +doesn't have to be complicated, right? + + + align:start position:0% +doesn't have to be complicated, right? +This is very simple data. But uh + + align:start position:0% + + + + align:start position:0% + +that's 53 54. + + align:start position:0% + + + + align:start position:0% + +Now this is a this is a histogram + + align:start position:0% +Now this is a this is a histogram + + + align:start position:0% +Now this is a this is a histogram +histogram and it's a way of displaying + + align:start position:0% +histogram and it's a way of displaying + + + align:start position:0% +histogram and it's a way of displaying +data way of displaying data. Now we're + + align:start position:0% +data way of displaying data. Now we're + + + align:start position:0% +data way of displaying data. Now we're +going to relate that to the factory and + + align:start position:0% +going to relate that to the factory and + + + align:start position:0% +going to relate that to the factory and +to the engineering um and to our to our + + align:start position:0% +to the engineering um and to our to our + + + align:start position:0% +to the engineering um and to our to our +quality process. But we want you to be + + align:start position:0% +quality process. But we want you to be + + + align:start position:0% +quality process. But we want you to be +able to recognize that we we send you + + align:start position:0% +able to recognize that we we send you + + + align:start position:0% +able to recognize that we we send you +out to the to to solve problems and we + + align:start position:0% +out to the to to solve problems and we + + + align:start position:0% +out to the to to solve problems and we +want efficient ways of of plotting the + + align:start position:0% +want efficient ways of of plotting the + + + align:start position:0% +want efficient ways of of plotting the +data and um so this is a very very + + align:start position:0% +data and um so this is a very very + + + align:start position:0% +data and um so this is a very very +interesting and this shows a couple of + + align:start position:0% +interesting and this shows a couple of + + + align:start position:0% +interesting and this shows a couple of +things. One that there's a wide wide + + align:start position:0% +things. One that there's a wide wide + + + align:start position:0% +things. One that there's a wide wide +variability wide variability in in the + + align:start position:0% +variability wide variability in in the + + + align:start position:0% +variability wide variability in in the +the count. Now um how just here's a + + align:start position:0% +the count. Now um how just here's a + + + align:start position:0% +the count. Now um how just here's a +question. Is everybody done sorting + + align:start position:0% +question. Is everybody done sorting + + + align:start position:0% +question. Is everybody done sorting +their everybody done sorting? I think + + align:start position:0% +their everybody done sorting? I think + + + align:start position:0% +their everybody done sorting? I think +most of the folks are done count I mean + + align:start position:0% +most of the folks are done count I mean + + + align:start position:0% +most of the folks are done count I mean +count how many reds and okay but all + + align:start position:0% +count how many reds and okay but all + + + align:start position:0% +count how many reds and okay but all +right now it turns out + + align:start position:0% +right now it turns out + + + align:start position:0% +right now it turns out +looking at this data do you think that + + align:start position:0% +looking at this data do you think that + + + align:start position:0% +looking at this data do you think that +Eminem controls their process by the + + align:start position:0% +Eminem controls their process by the + + + align:start position:0% +Eminem controls their process by the +count? + + align:start position:0% +count? + + + align:start position:0% +count? +What do you think they control it by? + + align:start position:0% +What do you think they control it by? + + + align:start position:0% +What do you think they control it by? +Weight. Right. Good. Now, if you take a + + align:start position:0% +Weight. Right. Good. Now, if you take a + + + align:start position:0% +Weight. Right. Good. Now, if you take a +look on your bag, take a look on the bag + + align:start position:0% +look on your bag, take a look on the bag + + + align:start position:0% +look on your bag, take a look on the bag +on the front of it. Ah, you've already + + align:start position:0% +on the front of it. Ah, you've already + + + align:start position:0% +on the front of it. Ah, you've already +eaten it up, right? Okay. Okay. You see + + align:start position:0% +eaten it up, right? Okay. Okay. You see + + + align:start position:0% +eaten it up, right? Okay. Okay. You see +the net weight is 1.69 1.69 ounces. Now, + + align:start position:0% +the net weight is 1.69 1.69 ounces. Now, + + + align:start position:0% +the net weight is 1.69 1.69 ounces. Now, +to two decimal places or three + + align:start position:0% +to two decimal places or three + + + align:start position:0% +to two decimal places or three +significant places there, that's how + + align:start position:0% +significant places there, that's how + + + align:start position:0% +significant places there, that's how +they control the weight because the Food + + align:start position:0% +they control the weight because the Food + + + align:start position:0% +they control the weight because the Food +and Drug Administration and the weights + + align:start position:0% +and Drug Administration and the weights + + + align:start position:0% +and Drug Administration and the weights +and measures of the whatever state, you + + align:start position:0% +and measures of the whatever state, you + + + align:start position:0% +and measures of the whatever state, you +know, say that you cannot fraudulently + + align:start position:0% +know, say that you cannot fraudulently + + + align:start position:0% +know, say that you cannot fraudulently +uh, you know, uh, deceive the customer. + + align:start position:0% +uh, you know, uh, deceive the customer. + + + align:start position:0% +uh, you know, uh, deceive the customer. +So that's the the upper and lower + + align:start position:0% +So that's the the upper and lower + + + align:start position:0% +So that's the the upper and lower +control limits in their process + + align:start position:0% +control limits in their process + + + align:start position:0% +control limits in their process +typically is um you know is going to be + + align:start position:0% +typically is um you know is going to be + + + align:start position:0% +typically is um you know is going to be +on weight because they they can't they + + align:start position:0% +on weight because they they can't they + + + align:start position:0% +on weight because they they can't they +can't deceive the customer for whatever + + align:start position:0% +can't deceive the customer for whatever + + + align:start position:0% +can't deceive the customer for whatever +they charge for M&M's these days. In + + align:start position:0% +they charge for M&M's these days. In + + + align:start position:0% +they charge for M&M's these days. In +fact on this on this chart you can see + + align:start position:0% +fact on this on this chart you can see + + + align:start position:0% +fact on this on this chart you can see +something else interesting. Is this + + align:start position:0% +something else interesting. Is this + + + align:start position:0% +something else interesting. Is this +symmetrical? + + align:start position:0% + + + + align:start position:0% + +No. And where's the where's the steep + + align:start position:0% +No. And where's the where's the steep + + + align:start position:0% +No. And where's the where's the steep +edge? + + align:start position:0% +edge? + + + align:start position:0% +edge? +you know, below it because because + + align:start position:0% +you know, below it because because + + + align:start position:0% +you know, below it because because +they'll get in trouble if they + + align:start position:0% +they'll get in trouble if they + + + align:start position:0% +they'll get in trouble if they +underweight people, right? And they're + + align:start position:0% +underweight people, right? And they're + + + align:start position:0% +underweight people, right? And they're +probably a real strict legal spec on on + + align:start position:0% +probably a real strict legal spec on on + + + align:start position:0% +probably a real strict legal spec on on +how often you can screw up here. Well, + + align:start position:0% +how often you can screw up here. Well, + + + align:start position:0% +how often you can screw up here. Well, +this that's just M&M's, right? They + + align:start position:0% +this that's just M&M's, right? They + + + align:start position:0% +this that's just M&M's, right? They +don't want to give you too many extra, + + align:start position:0% +don't want to give you too many extra, + + + align:start position:0% +don't want to give you too many extra, +but you get a couple that if you get 60 + + align:start position:0% +but you get a couple that if you get 60 + + + align:start position:0% +but you get a couple that if you get 60 +every now and then, that's fine with + + align:start position:0% +every now and then, that's fine with + + + align:start position:0% +every now and then, that's fine with +them. Want to do some colors? + + align:start position:0% +them. Want to do some colors? + + + align:start position:0% +them. Want to do some colors? +So, uh, let's How many How many folks? + + align:start position:0% +So, uh, let's How many How many folks? + + + align:start position:0% +So, uh, let's How many How many folks? +Uh, let's talk about everybody. How How + + align:start position:0% +Uh, let's talk about everybody. How How + + + align:start position:0% +Uh, let's talk about everybody. How How +many red ones did you get? One. One. + + align:start position:0% +many red ones did you get? One. One. + + + align:start position:0% +many red ones did you get? One. One. +One. + + align:start position:0% + + + + align:start position:0% + +Really? Yeah. See, that's a good How + + align:start position:0% +Really? Yeah. See, that's a good How + + + align:start position:0% +Really? Yeah. See, that's a good How +about blues? How many blues? + + align:start position:0% +about blues? How many blues? + + + align:start position:0% +about blues? How many blues? +What is the difference between blue and + + align:start position:0% +What is the difference between blue and + + + align:start position:0% +What is the difference between blue and +Oh, + + align:start position:0% + + + + align:start position:0% + +you got + + align:start position:0% +you got + + + align:start position:0% +you got +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +those. + + align:start position:0% +those. + + + align:start position:0% +those. +How many How many blues did you get? + + align:start position:0% +How many How many blues did you get? + + + align:start position:0% +How many How many blues did you get? +18 11 14 + + align:start position:0% +18 11 14 + + + align:start position:0% +18 11 14 +Yeah, that's it. See, they don't control + + align:start position:0% +Yeah, that's it. See, they don't control + + + align:start position:0% +Yeah, that's it. See, they don't control +like they they mix them up very well, + + align:start position:0% +like they they mix them up very well, + + + align:start position:0% +like they they mix them up very well, +but I mean if anybody has little kids + + align:start position:0% +but I mean if anybody has little kids + + + align:start position:0% +but I mean if anybody has little kids +and the folks in the back have all been + + align:start position:0% +and the folks in the back have all been + + + align:start position:0% +and the folks in the back have all been +through that little kids fight over I + + align:start position:0% +through that little kids fight over I + + + align:start position:0% +through that little kids fight over I +want a red one. I want a yellow one. So + + align:start position:0% +want a red one. I want a yellow one. So + + + align:start position:0% +want a red one. I want a yellow one. So +they they try to mix them up, but we + + align:start position:0% +they they try to mix them up, but we + + + align:start position:0% +they they try to mix them up, but we +control the How about yellow? One, + + align:start position:0% +control the How about yellow? One, + + + align:start position:0% +control the How about yellow? One, +nine and one 10. Wow. Brown seven + + align:start position:0% +nine and one 10. Wow. Brown seven + + + align:start position:0% +nine and one 10. Wow. Brown seven +12. + + align:start position:0% +12. + + + align:start position:0% +12. +It's interesting because little kids + + align:start position:0% +It's interesting because little kids + + + align:start position:0% +It's interesting because little kids +typically don't like that color, you + + align:start position:0% +typically don't like that color, you + + + align:start position:0% +typically don't like that color, you +know. How about green? 15. + + align:start position:0% +know. How about green? 15. + + + align:start position:0% +know. How about green? 15. +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +Wow. Look at that. See? Okay. So, you + + align:start position:0% +Wow. Look at that. See? Okay. So, you + + + align:start position:0% +Wow. Look at that. See? Okay. So, you +get the You get the picture. We're not + + align:start position:0% +get the You get the picture. We're not + + + align:start position:0% +get the You get the picture. We're not +They They try to randomly control them, + + align:start position:0% +They They try to randomly control them, + + + align:start position:0% +They They try to randomly control them, +but in fact, they don't do it. But the + + align:start position:0% +but in fact, they don't do it. But the + + + align:start position:0% +but in fact, they don't do it. But the +the point of the story is and many of + + align:start position:0% +the point of the story is and many of + + + align:start position:0% +the point of the story is and many of +you many of them some of the folks over + + align:start position:0% +you many of them some of the folks over + + + align:start position:0% +you many of them some of the folks over +here and like here actually have them + + align:start position:0% +here and like here actually have them + + + align:start position:0% +here and like here actually have them +stacked in Pareto water and they + + align:start position:0% +stacked in Pareto water and they + + + align:start position:0% +stacked in Pareto water and they +actually have the M&M's stacked just + + align:start position:0% +actually have the M&M's stacked just + + + align:start position:0% +actually have the M&M's stacked just +like this and that's a PTO chart. Now + + align:start position:0% +like this and that's a PTO chart. Now + + + align:start position:0% +like this and that's a PTO chart. Now +let me just grab a blank piece of paper. + + align:start position:0% +let me just grab a blank piece of paper. + + + align:start position:0% +let me just grab a blank piece of paper. +The point the point of the tour and Earl + + align:start position:0% +The point the point of the tour and Earl + + + align:start position:0% +The point the point of the tour and Earl +and Hugh have heard me say this. There's + + align:start position:0% +and Hugh have heard me say this. There's + + + align:start position:0% +and Hugh have heard me say this. There's +probably no more important tool, no more + + align:start position:0% +probably no more important tool, no more + + + align:start position:0% +probably no more important tool, no more +important tool in the whole business of + + align:start position:0% +important tool in the whole business of + + + align:start position:0% +important tool in the whole business of +quality uh than than the PTO chart. Why? + + align:start position:0% +quality uh than than the PTO chart. Why? + + + align:start position:0% +quality uh than than the PTO chart. Why? +Because the PTO chart's easy to do. I + + align:start position:0% +Because the PTO chart's easy to do. I + + + align:start position:0% +Because the PTO chart's easy to do. I +mean, you know, you can do it just with + + align:start position:0% +mean, you know, you can do it just with + + + align:start position:0% +mean, you know, you can do it just with +the M&M's you can see here. But the + + align:start position:0% +the M&M's you can see here. But the + + + align:start position:0% +the M&M's you can see here. But the +point is quality is a data-driven + + align:start position:0% +point is quality is a data-driven + + + align:start position:0% +point is quality is a data-driven +exercise. And we have a problem a + + align:start position:0% +exercise. And we have a problem a + + + align:start position:0% +exercise. And we have a problem a +problem out in the factory delivering + + align:start position:0% +problem out in the factory delivering + + + align:start position:0% +problem out in the factory delivering +Honeywell + + align:start position:0% +Honeywell + + + align:start position:0% +Honeywell +Honeywell um uh computers for the flight + + align:start position:0% +Honeywell um uh computers for the flight + + + align:start position:0% +Honeywell um uh computers for the flight +control system of a MD11 using that as + + align:start position:0% +control system of a MD11 using that as + + + align:start position:0% +control system of a MD11 using that as +example and the point is we go out there + + align:start position:0% +example and the point is we go out there + + + align:start position:0% +example and the point is we go out there +and we in fact analyze them you know we + + align:start position:0% +and we in fact analyze them you know we + + + align:start position:0% +and we in fact analyze them you know we +try to find out what's going on and we + + align:start position:0% +try to find out what's going on and we + + + align:start position:0% +try to find out what's going on and we +take a whole bunch of the computers and + + align:start position:0% +take a whole bunch of the computers and + + + align:start position:0% +take a whole bunch of the computers and +try to find out what the root cause of + + align:start position:0% +try to find out what the root cause of + + + align:start position:0% +try to find out what the root cause of +the problem is and so we wind up you + + align:start position:0% +the problem is and so we wind up you + + + align:start position:0% +the problem is and so we wind up you +know with a Pareto chart and we said + + align:start position:0% +know with a Pareto chart and we said + + + align:start position:0% +know with a Pareto chart and we said +part of them in fact is the the is the + + align:start position:0% +part of them in fact is the the is the + + + align:start position:0% +part of them in fact is the the is the +power supplies and you know this number + + align:start position:0% +power supplies and you know this number + + + align:start position:0% +power supplies and you know this number +of these guys had defective grounds + + align:start position:0% +of these guys had defective grounds + + + align:start position:0% +of these guys had defective grounds +and these number you know basically had + + align:start position:0% +and these number you know basically had + + + align:start position:0% +and these number you know basically had +a tolerance problem you know on the + + align:start position:0% +a tolerance problem you know on the + + + align:start position:0% +a tolerance problem you know on the +output you know that kind of thing. So + + align:start position:0% +output you know that kind of thing. So + + + align:start position:0% +output you know that kind of thing. So +what we do is that you know with that + + align:start position:0% +what we do is that you know with that + + + align:start position:0% +what we do is that you know with that +kind of data go back to the engineers + + align:start position:0% +kind of data go back to the engineers + + + align:start position:0% +kind of data go back to the engineers +and say holy cow you know what's going + + align:start position:0% +and say holy cow you know what's going + + + align:start position:0% +and say holy cow you know what's going +on the power supply and he said you know + + align:start position:0% +on the power supply and he said you know + + + align:start position:0% +on the power supply and he said you know +we just changed suppliers we just went + + align:start position:0% +we just changed suppliers we just went + + + align:start position:0% +we just changed suppliers we just went +from + + align:start position:0% +from + + + align:start position:0% +from +you know General Electric to + + align:start position:0% +you know General Electric to + + + align:start position:0% +you know General Electric to +Westinghouse on that in fact this is a + + align:start position:0% +Westinghouse on that in fact this is a + + + align:start position:0% +Westinghouse on that in fact this is a +real case on Westinghouse Westinghouse + + align:start position:0% +real case on Westinghouse Westinghouse + + + align:start position:0% +real case on Westinghouse Westinghouse +offloaded to an outfit in Puerto Rico + + align:start position:0% +offloaded to an outfit in Puerto Rico + + + align:start position:0% +offloaded to an outfit in Puerto Rico +and you know we were getting terrible + + align:start position:0% +and you know we were getting terrible + + + align:start position:0% +and you know we were getting terrible +terrible quality okay that's one kind of + + align:start position:0% +terrible quality okay that's one kind of + + + align:start position:0% +terrible quality okay that's one kind of +a thing let's talk about + + align:start position:0% +a thing let's talk about + + + align:start position:0% +a thing let's talk about +let's talk about late deliveries. Why + + align:start position:0% +let's talk about late deliveries. Why + + + align:start position:0% +let's talk about late deliveries. Why +are we getting late deliveries of an + + align:start position:0% +are we getting late deliveries of an + + + align:start position:0% +are we getting late deliveries of an +actuator? Okay, + + align:start position:0% +actuator? Okay, + + + align:start position:0% +actuator? Okay, +we failed test. + + align:start position:0% +we failed test. + + + align:start position:0% +we failed test. +We had a supply problem. Didn't get all + + align:start position:0% +We had a supply problem. Didn't get all + + + align:start position:0% +We had a supply problem. Didn't get all +the parts. + + align:start position:0% +the parts. + + + align:start position:0% +the parts. +We wound up with a situation where we + + align:start position:0% +We wound up with a situation where we + + + align:start position:0% +We wound up with a situation where we +had an engineering error in the Okay, + + align:start position:0% +had an engineering error in the Okay, + + + align:start position:0% +had an engineering error in the Okay, +that wasn't caught. Uh it was actually + + align:start position:0% +that wasn't caught. Uh it was actually + + + align:start position:0% +that wasn't caught. Uh it was actually +an engineering change. Okay. So you know + + align:start position:0% +an engineering change. Okay. So you know + + + align:start position:0% +an engineering change. Okay. So you know +we what's wrong with the test Earl + + align:start position:0% +we what's wrong with the test Earl + + + align:start position:0% +we what's wrong with the test Earl +yesterday? And and do you remember the + + align:start position:0% +yesterday? And and do you remember the + + + align:start position:0% +yesterday? And and do you remember the +drill about the five W's? The five W's, + + align:start position:0% +drill about the five W's? The five W's, + + + align:start position:0% +drill about the five W's? The five W's, +you know, why is the test wrong? Is it + + align:start position:0% +you know, why is the test wrong? Is it + + + align:start position:0% +you know, why is the test wrong? Is it +the So we drive it down to the next + + align:start position:0% +the So we drive it down to the next + + + align:start position:0% +the So we drive it down to the next +area, you know, and is it is it + + align:start position:0% +area, you know, and is it is it + + + align:start position:0% +area, you know, and is it is it +calibration? + + align:start position:0% +calibration? + + + align:start position:0% +calibration? +You know, is it a bad setup? So you just + + align:start position:0% +You know, is it a bad setup? So you just + + + align:start position:0% +You know, is it a bad setup? So you just +keep on drilling down. Now the other + + align:start position:0% +keep on drilling down. Now the other + + + align:start position:0% +keep on drilling down. Now the other +issue from a lean standpoint if you go + + align:start position:0% +issue from a lean standpoint if you go + + + align:start position:0% +issue from a lean standpoint if you go +out and work in a lean environment and + + align:start position:0% +out and work in a lean environment and + + + align:start position:0% +out and work in a lean environment and +Ida can tell you you know they don't + + align:start position:0% +Ida can tell you you know they don't + + + align:start position:0% +Ida can tell you you know they don't +give you unlimited lean budget you got a + + align:start position:0% +give you unlimited lean budget you got a + + + align:start position:0% +give you unlimited lean budget you got a +lean staff and the point is where are we + + align:start position:0% +lean staff and the point is where are we + + + align:start position:0% +lean staff and the point is where are we +going to spend our money to solve the + + align:start position:0% +going to spend our money to solve the + + + align:start position:0% +going to spend our money to solve the +biggest problems first and where are our + + align:start position:0% +biggest problems first and where are our + + + align:start position:0% +biggest problems first and where are our +biggest problems and if we can make you + + align:start position:0% +biggest problems and if we can make you + + + align:start position:0% +biggest problems and if we can make you +know with a red line here if we can make + + align:start position:0% +know with a red line here if we can make + + + align:start position:0% +know with a red line here if we can make +you know a 25% + + align:start position:0% +you know a 25% + + + align:start position:0% +you know a 25% +improvement in our biggest item it's + + align:start position:0% +improvement in our biggest item it's + + + align:start position:0% +improvement in our biggest item it's +better than you know eliminating a whole + + align:start position:0% +better than you know eliminating a whole + + + align:start position:0% +better than you know eliminating a whole +problem over And we only Which ones do + + align:start position:0% +problem over And we only Which ones do + + + align:start position:0% +problem over And we only Which ones do +we attack first? Which budget item? + + align:start position:0% +we attack first? Which budget item? + + + align:start position:0% +we attack first? Which budget item? +We're over We're over budget. We're over + + align:start position:0% +We're over We're over budget. We're over + + + align:start position:0% +We're over We're over budget. We're over +budget. + + align:start position:0% +budget. + + + align:start position:0% +budget. +Why? Well, where are we spending our + + align:start position:0% +Why? Well, where are we spending our + + + align:start position:0% +Why? Well, where are we spending our +money? Where are we spending our money? + + align:start position:0% +money? Where are we spending our money? + + + align:start position:0% +money? Where are we spending our money? +We're spending our money in uh + + align:start position:0% +We're spending our money in uh + + + align:start position:0% +We're spending our money in uh +utilities. + + align:start position:0% + + + + align:start position:0% + +We're spending our money in, you know, + + align:start position:0% +We're spending our money in, you know, + + + align:start position:0% +We're spending our money in, you know, +capital. We're spending our money in, + + align:start position:0% +capital. We're spending our money in, + + + align:start position:0% +capital. We're spending our money in, +you know, overhead kind of stuff. Well, + + align:start position:0% +you know, overhead kind of stuff. Well, + + + align:start position:0% +you know, overhead kind of stuff. Well, +you know, we go through a big drill. + + align:start position:0% +you know, we go through a big drill. + + + align:start position:0% +you know, we go through a big drill. +What what part of this is what part of + + align:start position:0% +What what part of this is what part of + + + align:start position:0% +What what part of this is what part of +that utility budget is electricity? + + align:start position:0% +that utility budget is electricity? + + + align:start position:0% +that utility budget is electricity? +Turns out to be very very high. Very + + align:start position:0% +Turns out to be very very high. Very + + + align:start position:0% +Turns out to be very very high. Very +very high. And so you go and put in and + + align:start position:0% +very high. And so you go and put in and + + + align:start position:0% +very high. And so you go and put in and +I wound up putting in a whole big plant + + align:start position:0% +I wound up putting in a whole big plant + + + align:start position:0% +I wound up putting in a whole big plant +of um uh a uh thermal generating plant + + align:start position:0% +of um uh a uh thermal generating plant + + + align:start position:0% +of um uh a uh thermal generating plant +to to reduce our electricity cost. So + + align:start position:0% +to to reduce our electricity cost. So + + + align:start position:0% +to to reduce our electricity cost. So +another another great tool is called the + + align:start position:0% +another another great tool is called the + + + align:start position:0% +another another great tool is called the +the cause and effect diagram. This is + + align:start position:0% +the cause and effect diagram. This is + + + align:start position:0% +the cause and effect diagram. This is +the the Japanese name for this is the + + align:start position:0% +the the Japanese name for this is the + + + align:start position:0% +the the Japanese name for this is the +Ishikawa diagram because Dr. Ishikawa + + align:start position:0% +Ishikawa diagram because Dr. Ishikawa + + + align:start position:0% +Ishikawa diagram because Dr. Ishikawa +came up with this. And in the old days, + + align:start position:0% +came up with this. And in the old days, + + + align:start position:0% +came up with this. And in the old days, +in the old days, this was called the 5M. + + align:start position:0% +in the old days, this was called the 5M. + + + align:start position:0% +in the old days, this was called the 5M. +It was measurement, material, methods, + + align:start position:0% +It was measurement, material, methods, + + + align:start position:0% +It was measurement, material, methods, +machine, and manpower. Now we call it + + align:start position:0% +machine, and manpower. Now we call it + + + align:start position:0% +machine, and manpower. Now we call it +personnel. Okay? And we've added the + + align:start position:0% +personnel. Okay? And we've added the + + + align:start position:0% +personnel. Okay? And we've added the +environment to it. And you can you can + + align:start position:0% +environment to it. And you can you can + + + align:start position:0% +environment to it. And you can you can +say we're trying to understand we're + + align:start position:0% +say we're trying to understand we're + + + align:start position:0% +say we're trying to understand we're +trying to understand you know this + + align:start position:0% +trying to understand you know this + + + align:start position:0% +trying to understand you know this +Honeywell uh computer problem and we + + align:start position:0% +Honeywell uh computer problem and we + + + align:start position:0% +Honeywell uh computer problem and we +have this issue in terms of the testing + + align:start position:0% +have this issue in terms of the testing + + + align:start position:0% +have this issue in terms of the testing +you know that so now we say what's wrong + + align:start position:0% +you know that so now we say what's wrong + + + align:start position:0% +you know that so now we say what's wrong +so we look at measurement and and this + + align:start position:0% +so we look at measurement and and this + + + align:start position:0% +so we look at measurement and and this +is a brainstorming technique you get all + + align:start position:0% +is a brainstorming technique you get all + + + align:start position:0% +is a brainstorming technique you get all +the engineers the manufacturing guys the + + align:start position:0% +the engineers the manufacturing guys the + + + align:start position:0% +the engineers the manufacturing guys the +tooling guys there and you say you know + + align:start position:0% +tooling guys there and you say you know + + + align:start position:0% +tooling guys there and you say you know +is it a test calibration issue is + + align:start position:0% +is it a test calibration issue is + + + align:start position:0% +is it a test calibration issue is +the precision, we can't measure it close + + align:start position:0% +the precision, we can't measure it close + + + align:start position:0% +the precision, we can't measure it close +enough. Is it the fact that we're not + + align:start position:0% +enough. Is it the fact that we're not + + + align:start position:0% +enough. Is it the fact that we're not +getting repeatability? + + align:start position:0% +getting repeatability? + + + align:start position:0% +getting repeatability? +You know, in a material thing, we're + + align:start position:0% +You know, in a material thing, we're + + + align:start position:0% +You know, in a material thing, we're +getting bad tolerances on that piston + + align:start position:0% +getting bad tolerances on that piston + + + align:start position:0% +getting bad tolerances on that piston +that we're we're for the compressor, you + + align:start position:0% +that we're we're for the compressor, you + + + align:start position:0% +that we're we're for the compressor, you +know, a standard old fashioned + + align:start position:0% +know, a standard old fashioned + + + align:start position:0% +know, a standard old fashioned +compressor, you know, is it a M&P + + align:start position:0% +compressor, you know, is it a M&P + + + align:start position:0% +compressor, you know, is it a M&P +material process issue? Is it a geometry + + align:start position:0% +material process issue? Is it a geometry + + + align:start position:0% +material process issue? Is it a geometry +problem? Is there inclusions in the + + align:start position:0% +problem? Is there inclusions in the + + + align:start position:0% +problem? Is there inclusions in the +titanium forging which causes defects in + + align:start position:0% +titanium forging which causes defects in + + + align:start position:0% +titanium forging which causes defects in +it? And so forth. So you basically + + align:start position:0% +it? And so forth. So you basically + + + align:start position:0% +it? And so forth. So you basically +brainstorm the things that could be + + align:start position:0% +brainstorm the things that could be + + + align:start position:0% +brainstorm the things that could be +driving the issue and then you send a + + align:start position:0% +driving the issue and then you send a + + + align:start position:0% +driving the issue and then you send a +little team out to get get some + + align:start position:0% +little team out to get get some + + + align:start position:0% +little team out to get get some +measurements and then have a meeting + + align:start position:0% +measurements and then have a meeting + + + align:start position:0% +measurements and then have a meeting +next week and say what' you find about + + align:start position:0% +next week and say what' you find about + + + align:start position:0% +next week and say what' you find about +the calibration. The guy says okay so + + align:start position:0% +the calibration. The guy says okay so + + + align:start position:0% +the calibration. The guy says okay so +that may not be the issue. So th this is + + align:start position:0% +that may not be the issue. So th this is + + + align:start position:0% +that may not be the issue. So th this is +a great way of displaying the results of + + align:start position:0% +a great way of displaying the results of + + + align:start position:0% +a great way of displaying the results of +brainstorming and giving your + + align:start position:0% +brainstorming and giving your + + + align:start position:0% +brainstorming and giving your +uh the quality engineers and engineers + + align:start position:0% +uh the quality engineers and engineers + + + align:start position:0% +uh the quality engineers and engineers +uh a tremendous way of organizing your + + align:start position:0% +uh a tremendous way of organizing your + + + align:start position:0% +uh a tremendous way of organizing your +your uh search efforts to get rid of the + + align:start position:0% +your uh search efforts to get rid of the + + + align:start position:0% +your uh search efforts to get rid of the +the errors and get high quality. So + + align:start position:0% +the errors and get high quality. So + + + align:start position:0% +the errors and get high quality. So +we're talking about inputs. You know, + + align:start position:0% +we're talking about inputs. You know, + + + align:start position:0% +we're talking about inputs. You know, +Earl talked to you about a process the + + align:start position:0% +Earl talked to you about a process the + + + align:start position:0% +Earl talked to you about a process the +other day, and one of the things that we + + align:start position:0% +other day, and one of the things that we + + + align:start position:0% +other day, and one of the things that we +want to do is to be able to get a + + align:start position:0% +want to do is to be able to get a + + + align:start position:0% +want to do is to be able to get a +repeatable process. I mentioned machine + + align:start position:0% +repeatable process. I mentioned machine + + + align:start position:0% +repeatable process. I mentioned machine +part plus or minus 15,000 and we measure + + align:start position:0% +part plus or minus 15,000 and we measure + + + align:start position:0% +part plus or minus 15,000 and we measure +the parts that are coming out of the + + align:start position:0% +the parts that are coming out of the + + + align:start position:0% +the parts that are coming out of the +process and uh we want to ensure + + align:start position:0% +process and uh we want to ensure + + + align:start position:0% +process and uh we want to ensure +that a high percentage of our output + + align:start position:0% +that a high percentage of our output + + + align:start position:0% +that a high percentage of our output +would like to have 100% of the output in + + align:start position:0% +would like to have 100% of the output in + + + align:start position:0% +would like to have 100% of the output in +fact meet our tolerances. So what we're + + align:start position:0% +fact meet our tolerances. So what we're + + + align:start position:0% +fact meet our tolerances. So what we're +trying to do is basically + + align:start position:0% +trying to do is basically + + + align:start position:0% +trying to do is basically +if we have if we have + + align:start position:0% +if we have if we have + + + align:start position:0% +if we have if we have +nonquality we want to identify the + + align:start position:0% +nonquality we want to identify the + + + align:start position:0% +nonquality we want to identify the +opportunities we want to define them. We + + align:start position:0% +opportunities we want to define them. We + + + align:start position:0% +opportunities we want to define them. We +define them with histograms and so forth + + align:start position:0% +define them with histograms and so forth + + + align:start position:0% +define them with histograms and so forth +and then we pareto them and then we want + + align:start position:0% +and then we pareto them and then we want + + + align:start position:0% +and then we pareto them and then we want +to identify the root cause and we want + + align:start position:0% +to identify the root cause and we want + + + align:start position:0% +to identify the root cause and we want +to take corrective action and then we + + align:start position:0% +to take corrective action and then we + + + align:start position:0% +to take corrective action and then we +want to see if we can get if the + + align:start position:0% +want to see if we can get if the + + + align:start position:0% +want to see if we can get if the +corrective action brings our + + align:start position:0% +corrective action brings our + + + align:start position:0% +corrective action brings our +measured output the measured output + + align:start position:0% +measured output the measured output + + + align:start position:0% +measured output the measured output +within the upper and lower control + + align:start position:0% +within the upper and lower control + + + align:start position:0% +within the upper and lower control +limits of a control chart and we're + + align:start position:0% +limits of a control chart and we're + + + align:start position:0% +limits of a control chart and we're +going to move into that. So there's a + + align:start position:0% +going to move into that. So there's a + + + align:start position:0% +going to move into that. So there's a +couple of terms that are used common + + align:start position:0% +couple of terms that are used common + + + align:start position:0% +couple of terms that are used common +cause and special cause. Common cause is + + align:start position:0% +cause and special cause. Common cause is + + + align:start position:0% +cause and special cause. Common cause is +basically variability that you saw in + + align:start position:0% +basically variability that you saw in + + + align:start position:0% +basically variability that you saw in +rolling the dice and so forth. And that + + align:start position:0% +rolling the dice and so forth. And that + + + align:start position:0% +rolling the dice and so forth. And that +happens uh in in um uh in uh measurement + + align:start position:0% +happens uh in in um uh in uh measurement + + + align:start position:0% +happens uh in in um uh in uh measurement +of uh machine parts or in electricity + + align:start position:0% +of uh machine parts or in electricity + + + align:start position:0% +of uh machine parts or in electricity +and so forth. But special causes are the + + align:start position:0% +and so forth. But special causes are the + + + align:start position:0% +and so forth. But special causes are the +fact is that there's something wrong. + + align:start position:0% +fact is that there's something wrong. + + + align:start position:0% +fact is that there's something wrong. +We haven't trained the people right. We + + align:start position:0% +We haven't trained the people right. We + + + align:start position:0% +We haven't trained the people right. We +have a machine that's not operating. We + + align:start position:0% +have a machine that's not operating. We + + + align:start position:0% +have a machine that's not operating. We +have defects in the material. the method + + align:start position:0% +have defects in the material. the method + + + align:start position:0% +have defects in the material. the method +has been changed and the the folks + + align:start position:0% +has been changed and the the folks + + + align:start position:0% +has been changed and the the folks +didn't catch that and and the occurrence + + align:start position:0% +didn't catch that and and the occurrence + + + align:start position:0% +didn't catch that and and the occurrence +of a special or what we call it + + align:start position:0% +of a special or what we call it + + + align:start position:0% +of a special or what we call it +assignable cause + + align:start position:0% +assignable cause + + + align:start position:0% +assignable cause +typically drives an out of control + + align:start position:0% +typically drives an out of control + + + align:start position:0% +typically drives an out of control +condition and and so we have to go look + + align:start position:0% +condition and and so we have to go look + + + align:start position:0% +condition and and so we have to go look +for that and we use a control chart to + + align:start position:0% +for that and we use a control chart to + + + align:start position:0% +for that and we use a control chart to +do that. So control charting is the + + align:start position:0% +do that. So control charting is the + + + align:start position:0% +do that. So control charting is the +primary tool of statistical process + + align:start position:0% +primary tool of statistical process + + + align:start position:0% +primary tool of statistical process +control. And you I showed your chart the + + align:start position:0% +control. And you I showed your chart the + + + align:start position:0% +control. And you I showed your chart the +other day and you'll probably see it + + align:start position:0% +other day and you'll probably see it + + + align:start position:0% +other day and you'll probably see it +again here that the fact is that what we + + align:start position:0% +again here that the fact is that what we + + + align:start position:0% +again here that the fact is that what we +we want engineering to design in a + + align:start position:0% +we want engineering to design in a + + + align:start position:0% +we want engineering to design in a +robust method so that our suppliers and + + align:start position:0% +robust method so that our suppliers and + + + align:start position:0% +robust method so that our suppliers and +our in-house fabrication can put their + + align:start position:0% +our in-house fabrication can put their + + + align:start position:0% +our in-house fabrication can put their +parts into statistical process control + + align:start position:0% +parts into statistical process control + + + align:start position:0% +parts into statistical process control +so that we get repeatable high quality. + + align:start position:0% +so that we get repeatable high quality. + + + align:start position:0% +so that we get repeatable high quality. +Repeatable high quality. And so what we + + align:start position:0% +Repeatable high quality. And so what we + + + align:start position:0% +Repeatable high quality. And so what we +want to do is so we're going to talk + + align:start position:0% +want to do is so we're going to talk + + + align:start position:0% +want to do is so we're going to talk +about SPC charts, statistical process + + align:start position:0% +about SPC charts, statistical process + + + align:start position:0% +about SPC charts, statistical process +control charts, time sequence charts + + align:start position:0% +control charts, time sequence charts + + + align:start position:0% +control charts, time sequence charts +that are important. \ No newline at end of file diff --git a/w_JWcGLiifU.txt b/w_JWcGLiifU.txt new file mode 100644 index 0000000000000000000000000000000000000000..bcb26e8db5087d59866876e04fedc5a41a1235f0 --- /dev/null +++ b/w_JWcGLiifU.txt @@ -0,0 +1,2004 @@ +ANNOUNCER: The following content +is provided under a + +Creative Commons license. + +Your support will help MIT +OpenCourseWare continue to + +offer high quality educational +resources for free. + +To make a donation or to view +additional materials from + +hundreds of MIT courses, visit +mitopencourseware@ocw.mit.edu. + +PROFESSOR: Hi. + +Welcome once again to our +lectures in Calculus + +Revisited, where today we are +going to talk about the + +calculus of composite +functions. + +Now, recall that we have already +mentioned in previous + +lectures the notion of +a composite function. + +And what we're going to do today +is to emphasize the idea + +as to how often we are called +upon to find functional + +relationships, where the first +variable is given in terms of + +a second variable, and the +second variable, say, is given + +in terms of the third +variable. + +And we wish to find, say, +the first variable in + +terms of the third. + +Fact here is where the name "the +chain rule" seems to come + +from, a chain reaction where the +variables are related in a + +chain this way. + +Now, we can see this quite +easily in terms of a diagram. + +Suppose, for example, +that I have a graph + +of 'x' versus 'y'. + +And suppose also, I have a +graph of 't' versus 'x'. + +Without any reference +to calculus-- + +and this is rather important-- + +without any reference to +calculus, notice that these + +two graphs together allow +me to visualize + +'y' in terms of 't'. + +For example, given a particular +value of 't'-- + +let's call it 't sub 1'-- + +given a value of 't', from that +value of 't', I can find + +the corresponding +value of 'x'. + +Let's call that 'x sub 1'. + +Now, knowing 'x sub 1', I can +come to this diagram. + +Knowing what 'x sub 1' is, +I can find 'y sub 1'. + +And so you see in this chain of +two diagrams, a particular + +value of 't' allows me to find +a particular value of 'y'. + +And in this particular way, +I can visualize 'y' as a + +function of 't'. + +And you see at this stage of the +game, there is absolutely + +no need to have to have any +knowledge of calculus to + +understand what it is that +we're discussing. + +The place that calculus comes +in is in the following way. + +Let's suppose it happened in +this first diagram that the + +graph of 'y' versus +'x' was smooth. + +In other words, let's assume +that 'y' is a differentiable + +function of 'x'. + +In particular, the way I've +drawn this diagram here, we're + +saying suppose 'dy dx' evaluated +at 'x' equals 'x1' + +happens to exist. + +And suppose also that this graph +of 'x' versus 't', this + +also happens to be a smooth +curve-- in other words, that + +'x' is a differentiable +function of 't'. + +Again, in the language of +calculus, what we're saying is + +the slope of this curve exists +at this particular point, and + +it's given by the 'x dt' +evaluated at 't' equals 't1'. + +Now, without going into a proof +at this stage, all we're + +saying is this. + +We suspect that if 'y' is a +differentiable function of + +'x', and 'x' is a differentiable +function of + +'t', that therefore, 'y' +should also be a + +differentiable function +of 't'. + +Notice it's not a conjecture +at all that if 'y' is a + +function of 'x' and 'x' is a +function of 't', that 'y' is a + +function of 't'. + +That part is clear. + +The conjecture is that we +suspect that if 'y' is a + +differentiable function +of 'x', and 'x' is a + +differentiable function of +'t', that 'y' will be a + +differentiable function +of 't'. + +In still other words, our +suspicion is perhaps that a + +differentiable function of a +differentiable function is + +again a differentiable +function. + +But even more to the point, not +only do we suspect, for + +example, that the 'dy dt' exists +here when 't' equals + +'t1', but in line with our +lecture of last time, we might + +even begin to suspect, in +terms of this fractional + +notation, that not only does +the 'dy dt' exist at 't' + +equals 't1', but it can be found +by multiplying 'dy dx' + +evaluated at 'x' equals 'x1' by +the 'x dt' evaluated at 't' + +equals 't1'. + +Again, almost as if the 'dx' +from the numerator here + +canceled with the 'dx' from the +denominator here, the same + +as what we hope our +differential + +notation would be. + +The question is granted that +we would like a result like + +this to hold true, in a course +such as calculus, where we're + +working with very tiny numbers +and quotients of small + +numbers, places where we've seen +that our intuition often + +leads us astray, it becomes +fairly apparent that we had + +better have something stronger +than just intuition in helping + +us derive certain results, no +matter how natural these + +results might look. + +Now, the way we proceed here +is as follows again, and + +notice again the building +blocks of calculus. + +We go back to the fundamental +result of last time. + +You see, after all, to find +'dy dt', we want 'delta y' + +divided by 'delta t', and then +we'll take the limit as 'delta + +t' approaches 0. + +The question is, first of all, +do we have a nice expression + +for 'delta y'? + +And in terms of the lecture of +last time, we saw that if 'y' + +was a differentiable function of +'x', that 'x' equals 'x1', + +that 'delta y' was given by ''dy +dx', evaluated 'x' equals + +'x1' times 'delta x'' plus +'k times delta x'-- + +and this is crucial now-- where +the limit of 'k' as + +'delta x' approaches 0 was 0. + +Now you see, this recipe +here is ironclad. + +I emphasized it from a geometric +point of view last + +time, but you may recall that I +proved it from an analytical + +point of view. + +In other words, whether you +want to visualize this or + +derive it, it makes +no difference. + +The key factors that this +statement here is ironclad. + +It's something that we now +know to be true in our + +so-called game of calculus. + +The point is, again, now how do +we use this to check over + +our conjectured result? + +Again, the answer is almost +straightforward. + +If you keep track of these +things, you'll notice that + +calculus is a one-step-at-a-time +procedure. + +Namely, we want 'dy dt'. + +That suggests we first want +'delta y' divided by 'delta + +t', and then we'll take +the limit as 'delta + +t' approaches 0. + +So first, we do this. + +Namely, starting with our +known recipe, we divide + +through by 'delta t', and +why can we do this? + +We can do this because, of +course, 'delta t' is not 0. + +Now we take the limit of both +sides of the equality as + +'delta t' approaches 0. + +We observe that on the left-hand +side, the limit of + +'delta y' divided by 'delta t', +as 'delta t' approaches 0, + +is precisely 'dy dt', and +in this particular case, + +evaluated at 't' equals 't1'. + +In other words, notice that the +left-hand side here, as we + +let 'delta t' approach 0, +becomes the left-hand side of + +our conjecture. + +Now we recall again that the +limit of the sum is the sum of + +the limits, and we now take +the limit of each of these + +terms separately, each +term as a product. + +The limit of a product is the +product of the limits. + +'dy dx' evaluated at 'x' equals +'x1' is a constant. + +In fact, that's just +what, it's 'dy'. + +The limit of 'dy dx' evaluated +'x' equals 'x1', as 'delta t' + +approaches 0, is just 'dy dx' +evaluated 'x' equals 'x1'. + +On the other hand, by +definition, the limit of + +'delta x' divided by 'delta t', +as 'delta t' approaches 0, + +is just 'dx dt'. + +And keeping track of the +subscripts here, later on + +we'll become sloppy and leave +the subscripts out. + +There really is no great +harm done in + +calculus of a single variable. + +We shall find, in calculus of +several variables, that it is + +extremely important to keep +track of the subscripts and + +where the variables are being +evaluated and things of this + +particular type. + +But I just want to get you used +to the fact that these + +are specific numbers that +we're using over here. + +Now let's continue. + +We take the limit of this term +as 'delta t' approaches 0. + +We observe that this becomes 'dx +dt', and the limit of 'k' + +as 'delta t' approaches 0-- + +well, as 'delta t' approaches +0, the fact that 'x' is a + +differentiable function of +'t' means that 'delta x' + +approaches 0. + +And since the limit of 'k' as +'delta x' approaches 0 is 0, + +this term becomes 0. + +0 times anything is, any +finite number, is 0. + +That means that this term here +in the limit becomes 0, and + +we're left with the +desired result. + +But notice that we did not +arrive at this desired result + +by hand waving. + +We did not say this term 'delta +x' is getting small, so + +it's becoming negligible. + +I can't emphasize this point +enough that it is true that + +'delta x' is becoming small +here, but so is 'delta t', and + +that indicates, essentially, +you're 0 over 0 form. + +And the thing that saves us, +the thing that makes this + +whole term drop out, is the key +fact that 'k' itself goes + +to 0, as 'delta x' goes to 0. + +By the way, there are easier +ways of intuitively trying to + +remember the chain rule. + +For example, one way that people +often try to visualize + +the chain rule is this. + +They'll say, OK, we +want 'dy dt'. + +So let's take 'delta y' divided +by 'delta t', and then + +we'll take the limit as 'delta +t' approaches 0. + +Now, you see in this notation +here, 'delta y' and 'delta t' + +are actually numbers. + +As numbers, we can write these +things in fractional notation, + +and we could write, what, that +'delta y' divided by 'delta t' + +is ''delta y' divided by 'delta +x'' times ''delta x' + +divided by 'delta t''. + +Then we could take the limit, +as delta t approaches 0, and + +we would arrive at +the same result. + +But again, without trying +to make this thing too + +obnoxiously long here, the thing +to keep in mind is that + +'x' is a function of 't'. + +And from a rigorous point of +view, the danger with this + +shortcut technique-- + +and it can be patched up but +requires a great deal of + +mathematical analysis-- + +the danger here is that as +'delta t' approaches 0, it's + +quite possible that 'delta +x' will be 0. + +In other words, it's possible +that for a given change in + +'t', there is no +change in 'x'. + +Now, if 'delta x' happens to +equal 0, then we're in + +trouble over here. + +In other words, in many cases, +this shortened version gives + +us an idea as to what's +going on. + +But our so-called longer method +has no pitfalls to it. + +But enough said for what +this recipe is. + +This result is known as the +chain rule, and this will be + +the topic of the rest +of today's lecture. + +Now, let's take a look at +some of these things + +in a bit more detail. + +For example, let's look +at an illustration. + +Suppose we want to find 'dy dx', +if 'y' is equal to ''x + +squared + 1' squared'. + +Let me first do this problem +the wrong way. + +Let's put a question +mark over here. + +People learn things like, what, +bring the exponent down + +and replace it by one less. + +Now certainly, if I bring the +exponent down here, and + +replace it by one less, this +is the answer that I get. + +Of course the question is, +is this the right answer? + +Well, you see, notice one very +nice way about finding out + +whether an answer is wrong, is +to first find out by another + +way which is the right answer. + +For example, if 'y' equals ''x +squared + 1' squared', it + +happens that we know how +to square this thing. + +We can find directly +that another way of + +expressing 'y' is what? + +It's 'x' to the fourth plus '2x +squared' plus 1, but we + +have previously learned how to +differentiate a polynomial. + +Through the polynomial is what, +this is going to be + +what? '4 x cubed' plus '4x'. + +And you see somehow or other, +this does not seem to give-- + +well, for one thing, we +see that these are + +two different answers. + +For another thing, if this is +the one that happens to be the + +right answer, this is the one +that is the wrong answer. + +And since we know from previous +material this is the + +right answer, there is something +wrong with this + +regardless of how right +it might look. + +In fact, how much are +we off by over here? + +If we factor this thing +out, what can we do? + +We can write this as '4x' +times 'x squared + 1'. + +And what we really had +over here was twice + +'x squared + 1'. + +It seems that the correction +factor is '2x'. + +Now again, notice that the +derivative of what's inside + +the parentheses over here just +happens to be exactly '2x'. + +Now how does the chain rule +come into play in a + +problem of this type? + +You see, the thing is, that what +we should do over here is + +rewrite this. + +Namely, for example, let 'u' +equal 'x squared + 1'. + +Then what this says is what? 'y' +is equal to 'u squared', + +where 'u' is equal to +'x squared + 1'. + +This is just another way of +writing this, and in this + +particular form, the +chain rule seems to + +be emphasized more. + +You see, 'y' is a function of +'u', 'u' is a function of 'x'. + +Notice that from the first +equation, it is relatively + +easy to find 'dy du'. + +In fact, it's just what, '2u'. + +We'll write that down later. + +From the second equation, it's +easy to find 'du dx'. + +And by the chain rule, all we're +saying is that 'dy du' + +times 'du dx' is 'dy dx'. + +See, what will that give +us in this case? + +'dy du' is '2u'. + +'du dx' is '2x'. + +That gives us '4x' times 'u'. + +'u' is 'x squared + 1', and so +this becomes '4x' times 'x + +squared + 1'. + +And if we now compare this +with what was the correct + +answer, we see that +in this case, + +everything worked out fine. + +I suppose what we should do here +is to comment now on the + +danger of memorizing recipes +without thoroughly + +understanding them. + +The idea, that said when you +want to differentiate + +something raised to a power that +you bring the power down + +and replace it by one less, +hinged on the fact that the + +thing that was being raised +to the power was the same + +variable with respect to which +you were doing the + +differentiation. + +You see, for example, when we +had 'y' equaled 'x squared', + +and then we wrote that 'dy dx' +is '2x', the thing that was + +important over here was +the fact that what? + +The thing that was being raised +to the second power is + +precisely the variable with +respect to which we were doing + +the differentiation. + +You see, in the problem 'y' +equals 'x squared + 1' + +squared, the thing that was +being raised to the second + +power was 'x squared + 1'. + +The variable with respect +to which we were + +differentiating was 'x'. + +In other words, to write this +thing more symbolically, if + +'y' is equal to something, +square it, then the derivative + +that's equal to twice that +something is the derivative of + +'y' with respect to +that something. + +You see, the place the chain +rule comes in is when the + +variable which appears here, +is not the same as the + +variable which appears here, and +we'll see this in greater + +detail as we go along. + +By the way, the chain rule comes +up in another form known + +as parametric equations, and +this form comes up very often. + +It's a twist of what we were +talking about before. + +This is the situation in which +frequently we want to compare + +two variables. + +Let's call them 'x' and +'y', all right? + +And it happens that both +variables, 'x' and 'y', can be + +expressed more simply in terms +of a third variable, 't'. + +And frequently, what one does +is try to talk about the + +relationship that exists between +'y' and 'x' in terms + +of eliminating t between +these two equations. + +By the way, in terms of +differential language, there + +seems to be an easier way +of handling this. + +Namely, you see, if we +differentiate the first + +equation, we get what, that +'dy dt' is 'f prime of t'. + +If we differentiate the second +equation, we get that 'dx dt' + +is 'g prime of t'. + +Now if, as we said in our last +lecture, we can pretend that + +this is really a fraction, +that it's + +'dy' divided by 'dt'-- + +in other words, if we think of +'dy' as being 'delta y-tan', + +of 'dx' as being 'delta x-tan', +and 'dt' as being + +'delta t', it would appear that +we could say, what, that + +'dy dt' divided by 'dx dt' +would just be what? + +'dy dx'. + +In other words, ''dy' divided +by 'dt'' divided by ''dx' + +divided by 'dt'', which is what +this would say if this + +was in differential form, +would just be 'dy dx'. + +In other words, we get the +feeling that to find the + +derivative here, all we have +to do is differentiate 'y' + +with respect to 't', and divide +that by the derivative + +of 'x' with respect to 't'. + +And by the way, you see, this +becomes a particularly + +powerful tool in those +computational cases where we + +do not know how to eliminate +'t', and to solve specifically + +for 'y' in terms of 'x'. + +You see, in terms of this +particular recipe over here, + +we are allowed to leave 'x' +and 'y' in terms of 't'. + +Again, the same old bugaboo +comes up to plague us. + +The fact that something seems +natural is not enough to allow + +us to believe that it's +actually correct. + +Is there a more rigorous way of +obtaining the same result? + +Again, the answer is yes. + +And not only is the answer yes, +but it goes back to the + +fundamental recipe that we +were discussing in our + +previous lecture. + +Namely, we know that 'delta y' +is ''f prime of t' times + +'delta t'' plus 'k1 delta t', +and the 'delta x' is ''g prime + +of t' times 'delta t'' plus 'k2 +delta t', where both the + +limit of 'k1' and 'k2' as +'delta t' approach 0. + +And this is a notation, I think, +that takes a while to + +get used to. + +We're used to seeing letters +like 'k' stand for constants, + +but it's important over here +to understand that 'k1' and + +'k2' are functions of 'delta +t', that the difference + +between 'delta y' and 'delta +y-tan', 'delta x' and 'delta + +x-tan', that difference, which +is 'k delta x' or 'k delta y', + +depending on which problem +we're dealing with that's + +certainly 'k' in that case, does +depend on how big 'delta + +t' happens to be. + +At any rate, the important thing +is that as 'delta t' + +approaches 0, these +go to 0 also. + +Now you see if we take this, and +actually compute 'delta y' + +divided by 'delta x'-- + +and we'll write this a little +bit more suggestively, factor + +out 'delta t' from both +numerator and denominator-- + +it rigorously tells us what +'delta y' divided + +by 'delta x' is. + +Now we take the limit, as +'delta x' approaches 0. + +That, by definition, is what? + +That's by definition 'dy dx'. + +Well, you see, first of all, +we cancel out the 'delta t' + +over here, see, 'delta t' is +not 0, we're assuming. + +Since it's not 0 it can be +canceled out, and once we've + +canceled out 'delta t', notice +that as 'delta t' approaches + +0, so does 'delta x'. + +As 'delta x' approaches +0, so does 'delta t'. + +That makes 'k1' and +'k2' go to 0. + +And then since the limit of a +quotient is the quotient of + +the limits, provided only the +'g prime of t' is not 0, we + +see that in the eliminating +process, we + +get the same answer. + +And by the way, see, once we +get the same answer, as we + +would have got the short way, +then we can use the + +convenience of the +short recipe. + +However, the fact that the short +recipe was nice is not + +enough of a guarantee +that it was giving + +us the correct answer. + +As a case in point, it's rather +interesting to point + +out that if you want the +second derivative-- + +in other words, let's recall +what we have here. + +We have what? 'y' was given +to 'b', say 'f of t'. + +'x' was given by 'g of t'. + +And you see from these two +equations, what we + +could do is find what? + +We could find the second +derivative of 'y with respect + +to t', and we could also find +from this equation the second + +derivative of 'x' with +respect to 't'. + +This we could certainly do. + +And mechanically, we could +certainly say, let's cancel + +the common denominator. + +The interesting thing is that +when you form that quotient, + +whatever that quotient is, it +does not come out to be the + +second derivative of 'y' +with respect to 'x'. + +And there is an interesting +piece of folklore over here. + +I don't know if this ever +bothered you or not, but it + +used to bother me. + +I never understood why, when +you talk about the second + +derivative, that the exponent +was written between the 'd' + +and the variable in one case, +but written at the end in the + +other case. + +In other words, notice that the +2 here appears between the + +'d' and the 'y', but +in the denominator, + +the 'd' appears outside. + +And again, it was the foresight +of the fathers of + +differential calculus who +noticed rather interestingly + +that if mechanically you did +agree to cancel the common + +denominator here, that what you +would wind up with is not + +'d2y dx squared', +but rather what? + +'d2y d2x'. + +In other words, if you +mechanically carried this out, + +notice that the notation +would be incorrect. + +The 2 comes out to be in the +wrong place over here. + +You see, again, the interesting +point is we don't + +have to rely on taking +my word for it. + +Somebody might say to me, now +look, all you've told me is + +that I get the wrong answer +solving this problem this + +particular way. + +And you've given me a nice +lecture about how the 2's come + +out the wrong way +and everything. + +How do I know that this +is the wrong answer? + +See, and again, everything +comes back to + +fundamentals again. + +To find 'd2y dx squared', +observe that by definition, + +that's just 'd dx' of 'dy dx'. + +That definition doesn't depend +on what functions we're + +dealing with. + +The second derivative with +respect to 'x' is the + +derivative with respect to 'x' +of the first derivative. + +Now, once we have this, you see, +knowing from our previous + +case, that what? + +'dy dx' was 'f prime of t' +divided by 'g prime of t'. + +We can now do what? + +Take this derivative. + +By the way, again, notice +how the chain + +rule comes up in practice. + +It's not always dictated +to us. + +If you look at the expression +inside the parentheses, what + +do we have? + +Inside the parentheses, we have +a function of 't' only. + +This is a function of 't'. + +We want to differentiate +it with respect to 'x'. + +The most natural variable to +differentiate a function of + +'t' with respect to +is 't' itself. + +In other words, what would've +been nice is if this was the + +derivative of 'f prime of t' +over 'g prime of t', with + +respect to 't'. + +See, this would be +easier to handle. + +We would then use the quotient +rule, et cetera. + +You see, we can differentiate +a function of 't' + +with respect to 't'. + +The trouble is we have +the derivative + +with respect to 'x'. + +And if we just change this to +a 't', that's cheating. + +See, I mean, you pretend you +copy it wrong, because it's an + +easier problem to +solve that way. + +The beauty of the chain rule is +that it allows us to do the + +problem the easier way, and +to doctor up the resulting + +incorrect answer by +the right answer. + +Namely, you see what we wanted +to wind up with here is what, + +the derivative not with respect +to 't', but with + +respect to 'x'. + +And so, by using the chain +rule, you see we do what? + +We take the derivative with +respect to 't', multiply that + +by 'dt dx'-- + +again, mechanically, almost +as if these canceled. + +But this is the way the chain +rule works, and now, you see, + +I can work this out by +the regular quotient + +rule, which says what? + +It's the denominator times the +derivative of the numerator. + +See, and I am differentiating +out respect to 't', the + +natural variable, minus the +numerator times the derivative + +of the denominator over the +square of the denominator. + +Now, that's a mess by itself, +meaning, what, + +computationally, it's +not that obvious. + +I mean, it's quite a bit of work +to do here, and then that + +whole thing must be multiplied +by 'dt dx'. + +And this, you see, is how one +goes around finding the second + +derivative of 'y' with respect +to 'x' in terms + +of parametric equations. + +And more than once, if you're +not careful, you're going to + +find yourself making serious +mistakes, by forgetting to put + +in this factor of 'dt dx'. + +By the way, an interesting +point is that we have not + +computed 'dt dx'. + +We have computed 'dx dt'. + +Let's go back here. + +See, 'x' was 'g of t'. + +So from that, 'dx dt' +is 'g prime of t'. + +And the question is if 'dx dt' +is 'g prime of t', how does + +one find 'dt dx'? + +And again, I think your +intuition is going to tell you + +to just take reciprocals. + +And again, the question is it's +true that this suggests + +taking reciprocals, but how do +we know that we can do this, + +and if we can do this, what +does it really mean? + +You see, what this is leading +into is what's going to be the + +subject of our lecture next +time, called 'Inverse + +Functions'. + +And just to give you a preview +of what that lecture is about, + +and how we work things like +this, let's take a look at + +what we mean by inverse +functions. + +Well, we won't even mention +it in much detail. + +But let's take a look and see +what's going on over here. + +Let's suppose that the first-- + +and by the way, I've started to +abandon using the 't' over + +here all the time. + +I think those of us in +engineering work primarily + +keep thinking of 't' as being +time, and you may get the + +mistaken notion that if the +variable isn't time, the thing + +doesn't work this way. + +In most cases, physically, the +variable that we're interested + +in will be time. + +But just for the idea of getting +you used to the fact + +that it makes no difference what +the name of the variable + +is, I've taken the liberty +of writing this slightly + +differently. + +Namely, I now assume that y is +a differentiable function of + +'u', and that 'u' is a + +differentiable function of 'x'. + +By the chain rule, I now know +that 'y' is a differentiable + +function of 'x', and that 'dy +dx' is 'dy du' times 'du dx'. + +The interesting thing here is, +is that there is nothing in + +the statement of the chain rule +that says that the first + +variable in the third that +'x' and 'y' must + +be different variables. + +In fact, it might happen that +'x' and 'y' are synonyms for + +one another. + +If 'x' and 'y' happen +to be synonyms-- + +suppose 'x' and 'y' +are synonyms-- + +look what happens over here. + +'dy dx' is then just 'dy +dy', which is 1. + +See, let's write that down. + +That's 'dy dy'. + +This would be 'dy du', and +if 'x' is equal to + +'y', this is 'du dy'. + +And if this is equal to 1, and +this is 'dy du', and this is + +'du dy', what does this tell +us about the relationship + +between 'dy du' and 'du dy'? + +It says their product is 1. + +And if the product is 1, that +by definition means that the + +two factors are reciprocals. + +Now, what I want you to observe +over here is what this + +whole thing means. + +Namely, if 'y' happens to equal +'x', do you see what + +this thing says? + +It says that 'y' is a +differentiable function of + +'u', and 'u' in turn is a + +differentiable function of 'y'. + +That's precisely what we +meant when we talked + +about inverse functions. + +We don't know when an inverse +function exists. + +All we're saying is, is that +if 'f inverse' happens to + +exist over here, to find 'du +dy', all we have to do is take + +the reciprocal of 'dy du'. + +Now again, this is +going to be the + +subject of our next lecture. + +All I wanted to do was to make +this aside for the time being. + +What I want to do to complete +today's lecture is to get to + +something more tangible. + +See, now that we've talked about +the chain rule, we've + +talked about inverse functions a +little bit, and talked about + +these things from a highly +theoretical point of view, + +let's go ahead and +try to solve a + +particularly simple problem. + +By particularly simple, +I mean this. + +I have chosen the numbers to +come out in a very, very easy + +way, so we don't get lost +in the maze of details. + +In other words, there was a +danger that we will confuse + +the computational details +with the theory. + +So to emphasize the theory, +I've tried to pick a + +straightforward simple problem, +but let's see how + +this thing works out. + +Let's suppose that we're given +that 'y' is equal to 't to the + +fourth power', and 'x' is +equal to 't squared'. + +What we would like to do-- and +by the way, notice what this + +thing says, a given value of 't' +determines both an 'x' and + +the 'y', so that makes 'x' and +'y' functionally related. + +Notice that from the first +equation, we can find that 'dy + +dt' is '4 t cubed'. + +From the second equation, we can +find that 'dx dt' is '2t'. + +And if we now use the chain +rule, 'dy dx' will be what? + +It'll be 'dy dt' divided +by 'dx dt', and + +that's just '2 t squared'. + +By the way, as a check, +notice this. + +If 'y' is equal to 't to the +fourth', and 'x' is equal to + +'t squared', since 't to the +fourth' is the square of 't + +squared', that says 'y' is +equal to ''t squared' + +squared', 'y' is equal +to 'x squared'. + +And if 'y' is equal to 'x +squared', in this case, it's + +very easy to see that 'dy +dx' is equal to '2x'. + +By the way, when we try to +compare these two answers, + +they look different, but +that's because they're + +expressed in terms of +different variables. + +If we return to our original +equations, and we see that 'x' + +is equal to 't squared'-- + +'x' is a synonym for +'t squared'-- + +this is the check that we have +received the right answer. + +By the way, before I conclude +today's lecture, I would like + +to make a rather +important aside + +about parametric equations. + +After one works the problem this +way, and comes down to + +the check, and says, hey, after +all of this mess over + +here, I could have replaced +it by just 'y' equals 'x + +squared', why did I have +to work with this + +in the first place? + +We are going to have many, many +examples throughout the + +course that will illustrate +this. + +But at least once in a lecture, +I would like to go on + +record as pointing out that this +pair of equations tells + +you much more than this +equation here. + +This equation simply +tells you this. + +If a particle were moving along +a curve with respect to + +time according to these +equations, this equation here + +simply tells you what path the +particle would follow. + +Namely, the parabola 'y' +equals 'x squared'. + +On the other hand, these +two equations tell you + +much more than that. + +These not only tell you that the +particle moved along the + +parabola 'y' equals 'x squared', +but rather, it tells + +you at a particular time the +point on the parabola that the + +particle was at. + +What I mean is this. + +As another example, suppose we +had 'y' equals 't squared,' + +and 'x' equals 't'. + +If we eliminate 't' from these +two equations, we also find + +that 'y' is equal +to 'x squared'. + +Yet notice that this is not the +same as our original set + +of equations. + +For example, here, when 't' is +2, when 't' is 2 over here, + +what point are we on as far as +the parabola is concerned? + +When 't' is 2, this is +2, and this is 4. + +That would be the +point 2 comma 4. + +On the other hand, with respect +to this equation, when + +'t' is 2, 'x' is 4, and 'y' is +16, you see both of these + +particles would follow the same +curve, but they are at + +different points at +different times. + +So don't belittle the +parametric approach. + +Having the parameter 't' in +there tells you more than just + +what the path of +the motion is. + +It tells you at what time +a particle was at what + +particular point. + +Well, enough about that. + +Let's go ahead and find the +second derivative now. + +You see, we already know that +'dy dx' is '2 t squared'. + +Now what we'd like to find +is 'd2y dx squared'. + +Again, the same basic +definition. + +'d2y dx squared'. + +The second derivative is the +derivative of the first + +derivative. + +The first derivative we saw was +'2 t squared', so this is + +the derivative of +'2 t squared'. + +Again, and this is where most +of the mistakes are made, + +people get sloppy. + +They forget the 'x' +is in here. + +They say I know the derivative +of this, it's '4t'. + +Well, the derivative of this is +'4t' with respect to 't'. + +We want to differentiate +with respect to 'x'. + +And the way the chain rule comes +in, we say OK, since 't' + +is the natural variable with +respect to which to + +differentiate, let's do it. + +We'll differentiate +in respect to 't'. + +But since the final answer has +to be with respect to 'x', our + +correction factor by the chain +rule will be 'dt dx'. + +Well, the derivative of '2 t +squared' with respect to 't' + +is clearly '4t'. + +The derivative of 't' with +respect to 'x', assuming that + +we know something about inverse +functions, that's the + +reciprocal of 'dx dt'. + +We just saw that 'dx +dt' was '2t'. + +Therefore, 'dt dx' is 1 over +'2t', and therefore, the + +correct answer appears +to be 2. + +Again, this is why I picked +the simple case. + +Given that 'y' equals 'x +squared', we see at a glance + +that 'dy dx' is equal to '2x', +and also at a glance, + +therefore, that 'd2y dx squared' +is equal to 2. + +By the way, that's exactly +what this is equal to. + +You see, had we forgot the chain +rule, and had we left + +this factor out, this would +have given us-- + +in other words, to simply write +down that the answer was + +'4t', which is the most common +mistake that's made, would + +have given us the +wrong answer. + +That's why I put such +an easy problem. + +You see, if I had picked a +tougher computational problem, + +the theory would have +remained the same. + +But when I got two different +answers, it would have been + +difficult to determine which +was the correct answer, and + +which was the incorrect +answer. + +But again, to summarize today's +lecture, it was a + +continuation in a way of the +lecture of last time, when we + +developed the primary recipe +involving differentials. + +Now we applied that +to find something + +called the chain rule. + +In the process of emphasizing +the chain rule, we talked + +about the necessity of +knowing something + +about inverse functions. + +Consequently, that dictates what +our next lecture will be + +concerned with, namely +inverse functions. + +And so until next +time, goodbye. + +ANNOUNCER: Funding for the +publication of this video was + +provided by the Gabriella and +Paul Rosenbaum Foundation. + +Help OCW continue to provide +free and open access to MIT + +courses by making a donation +at ocw.mit.edu/donate. \ No newline at end of file diff --git a/x0y7z-50ICc.txt b/x0y7z-50ICc.txt new file mode 100644 index 0000000000000000000000000000000000000000..f072856c1081a27fade2c64d24a82f0017e7c01b --- /dev/null +++ b/x0y7z-50ICc.txt @@ -0,0 +1,7755 @@ +align:start position:0% + +Well, last time + + align:start position:0% +Well, last time + + + align:start position:0% +Well, last time +we had seen that when you write this + + align:start position:0% +we had seen that when you write this + + + align:start position:0% +we had seen that when you write this +electron configuration + + align:start position:0% +electron configuration + + + align:start position:0% +electron configuration +that that electron configuration + + align:start position:0% +that that electron configuration + + + align:start position:0% +that that electron configuration +is a shorthand way of writing the wave + + align:start position:0% +is a shorthand way of writing the wave + + + align:start position:0% +is a shorthand way of writing the wave +functions for the electrons in a + + align:start position:0% +functions for the electrons in a + + + align:start position:0% +functions for the electrons in a +multi-electron atom within this one + + align:start position:0% +multi-electron atom within this one + + + align:start position:0% +multi-electron atom within this one +electron wave approximation. + + align:start position:0% +electron wave approximation. + + + align:start position:0% +electron wave approximation. +But we also noted + + align:start position:0% +But we also noted + + + align:start position:0% +But we also noted +that at most we gave or we assigned a + + align:start position:0% +that at most we gave or we assigned a + + + align:start position:0% +that at most we gave or we assigned a +hydrogen-like + + align:start position:0% +hydrogen-like + + + align:start position:0% +hydrogen-like +wave function to two electrons. + + align:start position:0% + + + + align:start position:0% + +And we noted that that was because of + + align:start position:0% +And we noted that that was because of + + + align:start position:0% +And we noted that that was because of +something you already knew about called + + align:start position:0% +something you already knew about called + + + align:start position:0% +something you already knew about called +spin. + + align:start position:0% +spin. + + + align:start position:0% +spin. +And spin last time + + align:start position:0% +And spin last time + + + align:start position:0% +And spin last time +we saw was a quantum mechanical + + align:start position:0% +we saw was a quantum mechanical + + + align:start position:0% +we saw was a quantum mechanical +phenomena. Spin is the intrinsic angular + + align:start position:0% +phenomena. Spin is the intrinsic angular + + + align:start position:0% +phenomena. Spin is the intrinsic angular +momentum built into the particle. + + align:start position:0% + + + + align:start position:0% + +And we saw that that spin is designated + + align:start position:0% +And we saw that that spin is designated + + + align:start position:0% +And we saw that that spin is designated +by a fourth quantum number. That fourth + + align:start position:0% +by a fourth quantum number. That fourth + + + align:start position:0% +by a fourth quantum number. That fourth +quantum number here is m subs and it had + + align:start position:0% +quantum number here is m subs and it had + + + align:start position:0% +quantum number here is m subs and it had +two allowed values. + + align:start position:0% +two allowed values. + + + align:start position:0% +two allowed values. +And those allowed values were 1/2 and + + align:start position:0% +And those allowed values were 1/2 and + + + align:start position:0% +And those allowed values were 1/2 and +minus one/2. + + align:start position:0% +minus one/2. + + + align:start position:0% +minus one/2. +And we said that those two allowed + + align:start position:0% +And we said that those two allowed + + + align:start position:0% +And we said that those two allowed +values for those two states represented + + align:start position:0% +values for those two states represented + + + align:start position:0% +values for those two states represented +a spin up and a spin down. + + align:start position:0% +a spin up and a spin down. + + + align:start position:0% +a spin up and a spin down. +Two different polarities in a sense of + + align:start position:0% +Two different polarities in a sense of + + + align:start position:0% +Two different polarities in a sense of +this quantum mechanical phenomenon + + align:start position:0% +this quantum mechanical phenomenon + + + align:start position:0% +this quantum mechanical phenomenon +called spin. + + align:start position:0% +called spin. + + + align:start position:0% +called spin. +All right. Now, how was uh spin actually + + align:start position:0% +All right. Now, how was uh spin actually + + + align:start position:0% +All right. Now, how was uh spin actually +uh experimentally observed? Well, + + align:start position:0% +uh experimentally observed? Well, + + + align:start position:0% +uh experimentally observed? Well, +really thanks to these two gentlemen. + + align:start position:0% +really thanks to these two gentlemen. + + + align:start position:0% +really thanks to these two gentlemen. +Here's Ulenbeck and Hoochmitt. + + align:start position:0% +Here's Ulenbeck and Hoochmitt. + + + align:start position:0% +Here's Ulenbeck and Hoochmitt. +These were very young scientists, I + + align:start position:0% +These were very young scientists, I + + + align:start position:0% +These were very young scientists, I +think posttocks at the time. And what + + align:start position:0% +think posttocks at the time. And what + + + align:start position:0% +think posttocks at the time. And what +they were doing, + + align:start position:0% +they were doing, + + + align:start position:0% +they were doing, +what they were doing was looking at the + + align:start position:0% +what they were doing was looking at the + + + align:start position:0% +what they were doing was looking at the +emission spectra from sodium atoms. + + align:start position:0% +emission spectra from sodium atoms. + + + align:start position:0% +emission spectra from sodium atoms. +And this is 1925. And so they knew + + align:start position:0% +And this is 1925. And so they knew + + + align:start position:0% +And this is 1925. And so they knew +enough already to know at what frequency + + align:start position:0% +enough already to know at what frequency + + + align:start position:0% +enough already to know at what frequency +they should expect to see some emission. + + align:start position:0% +they should expect to see some emission. + + + align:start position:0% +they should expect to see some emission. +And so they looked at the emission, + + align:start position:0% +And so they looked at the emission, + + + align:start position:0% +And so they looked at the emission, +dispersed it, looked at that frequency. + + align:start position:0% +dispersed it, looked at that frequency. + + + align:start position:0% +dispersed it, looked at that frequency. +And instead of seeing emission at that + + align:start position:0% +And instead of seeing emission at that + + + align:start position:0% +And instead of seeing emission at that +particular frequency where they + + align:start position:0% +particular frequency where they + + + align:start position:0% +particular frequency where they +expected, + + align:start position:0% +expected, + + + align:start position:0% +expected, +they saw so this is the expected what + + align:start position:0% +they saw so this is the expected what + + + align:start position:0% +they saw so this is the expected what +they really saw was some emission at a + + align:start position:0% +they really saw was some emission at a + + + align:start position:0% +they really saw was some emission at a +little bit lower frequency and some + + align:start position:0% +little bit lower frequency and some + + + align:start position:0% +little bit lower frequency and some +emission at a little bit higher + + align:start position:0% +emission at a little bit higher + + + align:start position:0% +emission at a little bit higher +frequency. Not much but a little bit + + align:start position:0% +frequency. Not much but a little bit + + + align:start position:0% +frequency. Not much but a little bit +lower and a little bit higher. Okay. And + + align:start position:0% +lower and a little bit higher. Okay. And + + + align:start position:0% +lower and a little bit higher. Okay. And +in spectroscopy, this kind of emission + + align:start position:0% +in spectroscopy, this kind of emission + + + align:start position:0% +in spectroscopy, this kind of emission +is actually called a dublet. + + align:start position:0% +is actually called a dublet. + + + align:start position:0% +is actually called a dublet. +Well, they were quite excited about it + + align:start position:0% +Well, they were quite excited about it + + + align:start position:0% +Well, they were quite excited about it +and thought much about the reason why + + align:start position:0% +and thought much about the reason why + + + align:start position:0% +and thought much about the reason why +there might be a dlet. + + align:start position:0% +there might be a dlet. + + + align:start position:0% +there might be a dlet. +And they reasoned that they could + + align:start position:0% +And they reasoned that they could + + + align:start position:0% +And they reasoned that they could +explain that dlet + + align:start position:0% +explain that dlet + + + align:start position:0% +explain that dlet +if the electron + + align:start position:0% +if the electron + + + align:start position:0% +if the electron +were existing in one of two states, one + + align:start position:0% +were existing in one of two states, one + + + align:start position:0% +were existing in one of two states, one +of two spin states. Hey, so this was + + align:start position:0% +of two spin states. Hey, so this was + + + align:start position:0% +of two spin states. Hey, so this was +revolutionary. + + align:start position:0% +revolutionary. + + + align:start position:0% +revolutionary. +And so they uh took their results + + align:start position:0% +And so they uh took their results + + + align:start position:0% +And so they uh took their results +excitedly to the resident established + + align:start position:0% +excitedly to the resident established + + + align:start position:0% +excitedly to the resident established +scientist that was uh closest who was + + align:start position:0% +scientist that was uh closest who was + + + align:start position:0% +scientist that was uh closest who was +Wolf Gang Powley. + + align:start position:0% +Wolf Gang Powley. + + + align:start position:0% +Wolf Gang Powley. +And Wolf Gang Powie was not a nice man. + + align:start position:0% +And Wolf Gang Powie was not a nice man. + + + align:start position:0% +And Wolf Gang Powie was not a nice man. +But they told Wolf Gang Powley about + + align:start position:0% +But they told Wolf Gang Powley about + + + align:start position:0% +But they told Wolf Gang Powley about +what they saw. And Wolf Gang said, + + align:start position:0% +what they saw. And Wolf Gang said, + + + align:start position:0% +what they saw. And Wolf Gang said, +"Rubbish. you publish that and you will + + align:start position:0% +"Rubbish. you publish that and you will + + + align:start position:0% +"Rubbish. you publish that and you will +destroy your scientific careers. + + align:start position:0% +destroy your scientific careers. + + + align:start position:0% +destroy your scientific careers. +And so they left dejectedly. + + align:start position:0% +And so they left dejectedly. + + + align:start position:0% +And so they left dejectedly. +No sooner had the door shut than Wolf + + align:start position:0% +No sooner had the door shut than Wolf + + + align:start position:0% +No sooner had the door shut than Wolf +Gang sat down and write wrote a paper on + + align:start position:0% +Gang sat down and write wrote a paper on + + + align:start position:0% +Gang sat down and write wrote a paper on +the presence of a fourth quantum number + + align:start position:0% +the presence of a fourth quantum number + + + align:start position:0% +the presence of a fourth quantum number +M subs. Okay, one of the travesties + + align:start position:0% +M subs. Okay, one of the travesties + + + align:start position:0% +M subs. Okay, one of the travesties +really in the history of science that's + + align:start position:0% +really in the history of science that's + + + align:start position:0% +really in the history of science that's +well known now. + + align:start position:0% +well known now. + + + align:start position:0% +well known now. +But um it really did take though dac + + align:start position:0% +But um it really did take though dac + + + align:start position:0% +But um it really did take though dac +another three years later to actually uh + + align:start position:0% +another three years later to actually uh + + + align:start position:0% +another three years later to actually uh +show where this m subs came from this + + align:start position:0% +show where this m subs came from this + + + align:start position:0% +show where this m subs came from this +fourth quantum number came from he had + + align:start position:0% +fourth quantum number came from he had + + + align:start position:0% +fourth quantum number came from he had +to use the relativistic Schroinger + + align:start position:0% +to use the relativistic Schroinger + + + align:start position:0% +to use the relativistic Schroinger +equation which we didn't look at he + + align:start position:0% +equation which we didn't look at he + + + align:start position:0% +equation which we didn't look at he +solved that and when he solve that out + + align:start position:0% +solved that and when he solve that out + + + align:start position:0% +solved that and when he solve that out +drops this fourth quantum number m subs + + align:start position:0% +drops this fourth quantum number m subs + + + align:start position:0% +drops this fourth quantum number m subs +okay but pie did make a contribution + + align:start position:0% +okay but pie did make a contribution + + + align:start position:0% +okay but pie did make a contribution +what he uh he worked on this problem and + + align:start position:0% +what he uh he worked on this problem and + + + align:start position:0% +what he uh he worked on this problem and +um + + align:start position:0% +um + + + align:start position:0% +um +worked on the theoretical basis of it + + align:start position:0% +worked on the theoretical basis of it + + + align:start position:0% +worked on the theoretical basis of it +and in the end came out something called + + align:start position:0% +and in the end came out something called + + + align:start position:0% +and in the end came out something called +the powi exclusion principle + + align:start position:0% +the powi exclusion principle + + + align:start position:0% +the powi exclusion principle +and the pi exclusion principle here + + align:start position:0% +and the pi exclusion principle here + + + align:start position:0% +and the pi exclusion principle here +simply says that no two electrons in the + + align:start position:0% +simply says that no two electrons in the + + + align:start position:0% +simply says that no two electrons in the +same atom can have the same electron + + align:start position:0% +same atom can have the same electron + + + align:start position:0% +same atom can have the same electron +wave function. + + align:start position:0% +wave function. + + + align:start position:0% +wave function. +and the same spin. + + align:start position:0% +and the same spin. + + + align:start position:0% +and the same spin. +Or another way to state that is that no + + align:start position:0% +Or another way to state that is that no + + + align:start position:0% +Or another way to state that is that no +two electrons in the same atom can have + + align:start position:0% +two electrons in the same atom can have + + + align:start position:0% +two electrons in the same atom can have +the same set of four quantum numbers. + + align:start position:0% +the same set of four quantum numbers. + + + align:start position:0% +the same set of four quantum numbers. +So for example, in our electron + + align:start position:0% +So for example, in our electron + + + align:start position:0% +So for example, in our electron +configuration here for neon, we've got + + align:start position:0% +configuration here for neon, we've got + + + align:start position:0% +configuration here for neon, we've got +two electrons in this 1s state. + + align:start position:0% +two electrons in this 1s state. + + + align:start position:0% +two electrons in this 1s state. +Well, this electron here has the quantum + + align:start position:0% +Well, this electron here has the quantum + + + align:start position:0% +Well, this electron here has the quantum +number 1 0 0 and 1/2. + + align:start position:0% +number 1 0 0 and 1/2. + + + align:start position:0% +number 1 0 0 and 1/2. +This electron also in that 1s state has + + align:start position:0% +This electron also in that 1s state has + + + align:start position:0% +This electron also in that 1s state has +the quantum numbers 1 0 0 minus one/2. + + align:start position:0% +the quantum numbers 1 0 0 minus one/2. + + + align:start position:0% +the quantum numbers 1 0 0 minus one/2. +So the nl and m quantum numbers are the + + align:start position:0% +So the nl and m quantum numbers are the + + + align:start position:0% +So the nl and m quantum numbers are the +same for these two electrons. But what's + + align:start position:0% +same for these two electrons. But what's + + + align:start position:0% +same for these two electrons. But what's +different is the spin quantum number. + + align:start position:0% +different is the spin quantum number. + + + align:start position:0% +different is the spin quantum number. +one is 1/2 and the other is minus one/2 + + align:start position:0% +one is 1/2 and the other is minus one/2 + + + align:start position:0% +one is 1/2 and the other is minus one/2 +according to the poly exclusion + + align:start position:0% +according to the poly exclusion + + + align:start position:0% +according to the poly exclusion +principle that says you can't have two + + align:start position:0% +principle that says you can't have two + + + align:start position:0% +principle that says you can't have two +electrons in the same atom with the same + + align:start position:0% +electrons in the same atom with the same + + + align:start position:0% +electrons in the same atom with the same +set of four quantum numbers and likewise + + align:start position:0% +set of four quantum numbers and likewise + + + align:start position:0% +set of four quantum numbers and likewise +for example this electron right here + + align:start position:0% +for example this electron right here + + + align:start position:0% +for example this electron right here +quantum numbers 2 1 minus one and plus + + align:start position:0% +quantum numbers 2 1 minus one and plus + + + align:start position:0% +quantum numbers 2 1 minus one and plus +one/2 + + align:start position:0% +one/2 + + + align:start position:0% +one/2 +but this electron quantum numbers 2 1 - + + align:start position:0% +but this electron quantum numbers 2 1 - + + + align:start position:0% +but this electron quantum numbers 2 1 - +one minus one minus one/2 no two + + align:start position:0% +one minus one minus one/2 no two + + + align:start position:0% +one minus one minus one/2 no two +electrons have the same set of four + + align:start position:0% +electrons have the same set of four + + + align:start position:0% +electrons have the same set of four +quantum numbers. All right. So that's + + align:start position:0% +quantum numbers. All right. So that's + + + align:start position:0% +quantum numbers. All right. So that's +why when we were um actually writing + + align:start position:0% +why when we were um actually writing + + + align:start position:0% +why when we were um actually writing +these electron configurations which is + + align:start position:0% +these electron configurations which is + + + align:start position:0% +these electron configurations which is +the shorthand representation for the + + align:start position:0% +the shorthand representation for the + + + align:start position:0% +the shorthand representation for the +wave functions + + align:start position:0% +wave functions + + + align:start position:0% +wave functions +in the one electron approximation for + + align:start position:0% +in the one electron approximation for + + + align:start position:0% +in the one electron approximation for +these multi-electron atoms. That's why + + align:start position:0% +these multi-electron atoms. That's why + + + align:start position:0% +these multi-electron atoms. That's why +we didn't give the 10 electrons in neon + + align:start position:0% +we didn't give the 10 electrons in neon + + + align:start position:0% +we didn't give the 10 electrons in neon +for example. We didn't all give that a + + align:start position:0% +for example. We didn't all give that a + + + align:start position:0% +for example. We didn't all give that a +1s hydrogen-like wave function. Okay. + + align:start position:0% +1s hydrogen-like wave function. Okay. + + + align:start position:0% +1s hydrogen-like wave function. Okay. +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +So now what we want to do is we want to + + align:start position:0% +So now what we want to do is we want to + + + align:start position:0% +So now what we want to do is we want to +take a look at what the wave functions + + align:start position:0% +take a look at what the wave functions + + + align:start position:0% +take a look at what the wave functions +for the individual electrons in a + + align:start position:0% +for the individual electrons in a + + + align:start position:0% +for the individual electrons in a +multi-electron atom actually look like. + + align:start position:0% +multi-electron atom actually look like. + + + align:start position:0% +multi-electron atom actually look like. +And to do that we're going to look at + + align:start position:0% +And to do that we're going to look at + + + align:start position:0% +And to do that we're going to look at +the radial probability distribution + + align:start position:0% +the radial probability distribution + + + align:start position:0% +the radial probability distribution +function. All right? because that tells + + align:start position:0% +function. All right? because that tells + + + align:start position:0% +function. All right? because that tells +us + + align:start position:0% +us + + + align:start position:0% +us +a little bit about what the wave + + align:start position:0% +a little bit about what the wave + + + align:start position:0% +a little bit about what the wave +functions look like, right? Because the + + align:start position:0% +functions look like, right? Because the + + + align:start position:0% +functions look like, right? Because the +radial probability distribution function + + align:start position:0% +radial probability distribution function + + + align:start position:0% +radial probability distribution function +as a function of r is the probability of + + align:start position:0% +as a function of r is the probability of + + + align:start position:0% +as a function of r is the probability of +finding the electron a distance between + + align:start position:0% +finding the electron a distance between + + + align:start position:0% +finding the electron a distance between +r and r + dr. All right, that's what the + + align:start position:0% +r and r + dr. All right, that's what the + + + align:start position:0% +r and r + dr. All right, that's what the +radial probability distribution function + + align:start position:0% +radial probability distribution function + + + align:start position:0% +radial probability distribution function +tells us. + + align:start position:0% +tells us. + + + align:start position:0% +tells us. +And so what I did here is to plot the + + align:start position:0% +And so what I did here is to plot the + + + align:start position:0% +And so what I did here is to plot the +wave the radial probability distribution + + align:start position:0% +wave the radial probability distribution + + + align:start position:0% +wave the radial probability distribution +functions for each one of the electrons + + align:start position:0% +functions for each one of the electrons + + + align:start position:0% +functions for each one of the electrons +in um the argon atom. Each one of the + + align:start position:0% +in um the argon atom. Each one of the + + + align:start position:0% +in um the argon atom. Each one of the +electrons in the different states for + + align:start position:0% +electrons in the different states for + + + align:start position:0% +electrons in the different states for +the argon atom. And the first thing that + + align:start position:0% +the argon atom. And the first thing that + + + align:start position:0% +the argon atom. And the first thing that +I want you to notice is that these + + align:start position:0% +I want you to notice is that these + + + align:start position:0% +I want you to notice is that these +radial probability distribution + + align:start position:0% +radial probability distribution + + + align:start position:0% +radial probability distribution +functions for each one of these + + align:start position:0% +functions for each one of these + + + align:start position:0% +functions for each one of these +electrons look very similar in shape to + + align:start position:0% +electrons look very similar in shape to + + + align:start position:0% +electrons look very similar in shape to +the radial probability distribution + + align:start position:0% +the radial probability distribution + + + align:start position:0% +the radial probability distribution +functions for the electron in a hydrogen + + align:start position:0% +functions for the electron in a hydrogen + + + align:start position:0% +functions for the electron in a hydrogen +atom. Okay, in fact they have the same + + align:start position:0% +atom. Okay, in fact they have the same + + + align:start position:0% +atom. Okay, in fact they have the same +shape. If you look here at the uh let me + + align:start position:0% +shape. If you look here at the uh let me + + + align:start position:0% +shape. If you look here at the uh let me +see if you look here at the 1s wave + + align:start position:0% +see if you look here at the 1s wave + + + align:start position:0% +see if you look here at the 1s wave +function which is in green here. All + + align:start position:0% +function which is in green here. All + + + align:start position:0% +function which is in green here. All +right. You see it starts out at zero as + + align:start position:0% +right. You see it starts out at zero as + + + align:start position:0% +right. You see it starts out at zero as +all radial probabilities do, increases, + + align:start position:0% +all radial probabilities do, increases, + + + align:start position:0% +all radial probabilities do, increases, +goes to a maximum, and then drops off + + align:start position:0% +goes to a maximum, and then drops off + + + align:start position:0% +goes to a maximum, and then drops off +exponentially. Hey, that's exactly what + + align:start position:0% +exponentially. Hey, that's exactly what + + + align:start position:0% +exponentially. Hey, that's exactly what +the 1s wave function did in a hydrogen + + align:start position:0% +the 1s wave function did in a hydrogen + + + align:start position:0% +the 1s wave function did in a hydrogen +atom. If you look at the 2s wave + + align:start position:0% +atom. If you look at the 2s wave + + + align:start position:0% +atom. If you look at the 2s wave +function, it starts out at zero, goes to + + align:start position:0% +function, it starts out at zero, goes to + + + align:start position:0% +function, it starts out at zero, goes to +a maximum, and then there's a node. + + align:start position:0% +a maximum, and then there's a node. + + + align:start position:0% +a maximum, and then there's a node. +There's a node right here, and then + + align:start position:0% +There's a node right here, and then + + + align:start position:0% +There's a node right here, and then +there goes to another maximum, + + align:start position:0% +there goes to another maximum, + + + align:start position:0% +there goes to another maximum, +exponentially decays. Hey, that's + + align:start position:0% +exponentially decays. Hey, that's + + + align:start position:0% +exponentially decays. Hey, that's +exactly what the 2s wave function looked + + align:start position:0% +exactly what the 2s wave function looked + + + align:start position:0% +exactly what the 2s wave function looked +like in the hydrogen atom. + + align:start position:0% +like in the hydrogen atom. + + + align:start position:0% +like in the hydrogen atom. +So for the multi-electron atoms, these + + align:start position:0% +So for the multi-electron atoms, these + + + align:start position:0% +So for the multi-electron atoms, these +wave functions have the same basic shape + + align:start position:0% +wave functions have the same basic shape + + + align:start position:0% +wave functions have the same basic shape +and they have the same nodal structure. + + align:start position:0% +and they have the same nodal structure. + + + align:start position:0% +and they have the same nodal structure. +All right, they have the same number of + + align:start position:0% +All right, they have the same number of + + + align:start position:0% +All right, they have the same number of +radial nodes, same number of angular + + align:start position:0% +radial nodes, same number of angular + + + align:start position:0% +radial nodes, same number of angular +nodes. + + align:start position:0% +nodes. + + + align:start position:0% +nodes. +The big difference between these wave + + align:start position:0% +The big difference between these wave + + + align:start position:0% +The big difference between these wave +functions and the hydrogen atom is the + + align:start position:0% +functions and the hydrogen atom is the + + + align:start position:0% +functions and the hydrogen atom is the +distance they the distances from the + + align:start position:0% +distance they the distances from the + + + align:start position:0% +distance they the distances from the +nucleus. For example, if you look at the + + align:start position:0% +nucleus. For example, if you look at the + + + align:start position:0% +nucleus. For example, if you look at the +1s radial probability distribution + + align:start position:0% +1s radial probability distribution + + + align:start position:0% +1s radial probability distribution +for argon, you find that that most + + align:start position:0% +for argon, you find that that most + + + align:start position:0% +for argon, you find that that most +probable value of r is a tenth of an a + + align:start position:0% +probable value of r is a tenth of an a + + + align:start position:0% +probable value of r is a tenth of an a +knot, right? a tenth of a bore radius. + + align:start position:0% +knot, right? a tenth of a bore radius. + + + align:start position:0% +knot, right? a tenth of a bore radius. +What was it for a hydrogen atom in the + + align:start position:0% +What was it for a hydrogen atom in the + + + align:start position:0% +What was it for a hydrogen atom in the +ground state? + + align:start position:0% +ground state? + + + align:start position:0% +ground state? +A not. Right? So this 1s electron here + + align:start position:0% +A not. Right? So this 1s electron here + + + align:start position:0% +A not. Right? So this 1s electron here +is 10 times closer on the average into + + align:start position:0% +is 10 times closer on the average into + + + align:start position:0% +is 10 times closer on the average into +the nucleus + + align:start position:0% +the nucleus + + + align:start position:0% +the nucleus +than the electron in a hydrogen atom. + + align:start position:0% +than the electron in a hydrogen atom. + + + align:start position:0% +than the electron in a hydrogen atom. +And the same is the case for the 2s wave + + align:start position:0% +And the same is the case for the 2s wave + + + align:start position:0% +And the same is the case for the 2s wave +function. 2p 3s 3p. It's all a lot + + align:start position:0% +function. 2p 3s 3p. It's all a lot + + + align:start position:0% +function. 2p 3s 3p. It's all a lot +closer in if you compared those actual + + align:start position:0% +closer in if you compared those actual + + + align:start position:0% +closer in if you compared those actual +values. And the reason it is is because + + align:start position:0% +values. And the reason it is is because + + + align:start position:0% +values. And the reason it is is because +of the kum attraction between the + + align:start position:0% +of the kum attraction between the + + + align:start position:0% +of the kum attraction between the +electron and the nucleus. As you go to + + align:start position:0% +electron and the nucleus. As you go to + + + align:start position:0% +electron and the nucleus. As you go to +argon, right, which has now a + 18 * e + + align:start position:0% +argon, right, which has now a + 18 * e + + + align:start position:0% +argon, right, which has now a + 18 * e +charge on the nucleus. Hey, that's a + + align:start position:0% +charge on the nucleus. Hey, that's a + + + align:start position:0% +charge on the nucleus. Hey, that's a +greater attractive interaction. The + + align:start position:0% +greater attractive interaction. The + + + align:start position:0% +greater attractive interaction. The +culum interaction is the charge on the + + align:start position:0% +culum interaction is the charge on the + + + align:start position:0% +culum interaction is the charge on the +electron times the charge on the + + align:start position:0% +electron times the charge on the + + + align:start position:0% +electron times the charge on the +nucleus. It is that greater electron uh + + align:start position:0% +nucleus. It is that greater electron uh + + + align:start position:0% +nucleus. It is that greater electron uh +attraction that pulls the electrons in + + align:start position:0% +attraction that pulls the electrons in + + + align:start position:0% +attraction that pulls the electrons in +closer to the nucleus. That's why that + + align:start position:0% +closer to the nucleus. That's why that + + + align:start position:0% +closer to the nucleus. That's why that +1s electron that most probable value of + + align:start position:0% +1s electron that most probable value of + + + align:start position:0% +1s electron that most probable value of +r is at a tenth of a knot instead of one + + align:start position:0% +r is at a tenth of a knot instead of one + + + align:start position:0% +r is at a tenth of a knot instead of one +a kn. Yes. + + align:start position:0% + + + + align:start position:0% + +trying to make larger and larger + + align:start position:0% +trying to make larger and larger + + + align:start position:0% +trying to make larger and larger +collapse. + + align:start position:0% +collapse. + + + align:start position:0% +collapse. +Um well certain they they don't collapse + + align:start position:0% +Um well certain they they don't collapse + + + align:start position:0% +Um well certain they they don't collapse +in a sense. They don't collapse into the + + align:start position:0% +in a sense. They don't collapse into the + + + align:start position:0% +in a sense. They don't collapse into the +nucleus. Certainly the probability of + + align:start position:0% +nucleus. Certainly the probability of + + + align:start position:0% +nucleus. Certainly the probability of +finding the electron closer to the + + align:start position:0% +finding the electron closer to the + + + align:start position:0% +finding the electron closer to the +nucleus is greater. But it is true that + + align:start position:0% +nucleus is greater. But it is true that + + + align:start position:0% +nucleus is greater. But it is true that +as you get larger and larger atoms, you + + align:start position:0% +as you get larger and larger atoms, you + + + align:start position:0% +as you get larger and larger atoms, you +have more and more electrons. And so + + align:start position:0% +have more and more electrons. And so + + + align:start position:0% +have more and more electrons. And so +they do generally get bigger, right? and + + align:start position:0% +they do generally get bigger, right? and + + + align:start position:0% +they do generally get bigger, right? and +and we'll see that when we actually look + + align:start position:0% +and we'll see that when we actually look + + + align:start position:0% +and we'll see that when we actually look +at the size and look at the trends in + + align:start position:0% +at the size and look at the trends in + + + align:start position:0% +at the size and look at the trends in +the radius as we go across and down the + + align:start position:0% +the radius as we go across and down the + + + align:start position:0% +the radius as we go across and down the +periodic table. We'll look at that a + + align:start position:0% +periodic table. We'll look at that a + + + align:start position:0% +periodic table. We'll look at that a +little bit more in detail. Okay? And + + align:start position:0% +little bit more in detail. Okay? And + + + align:start position:0% +little bit more in detail. Okay? And +we'll see that in general if you add + + align:start position:0% +we'll see that in general if you add + + + align:start position:0% +we'll see that in general if you add +electrons they get bigger, right? + + align:start position:0% +electrons they get bigger, right? + + + align:start position:0% +electrons they get bigger, right? +Because you do in fact have more + + align:start position:0% +Because you do in fact have more + + + align:start position:0% +Because you do in fact have more +electrons and you put them in these + + align:start position:0% +electrons and you put them in these + + + align:start position:0% +electrons and you put them in these +outer shells. All right? But if you just + + align:start position:0% +outer shells. All right? But if you just + + + align:start position:0% +outer shells. All right? But if you just +do a one-on-one comparison of 1 S to 1 S + + align:start position:0% +do a one-on-one comparison of 1 S to 1 S + + + align:start position:0% +do a one-on-one comparison of 1 S to 1 S +in hydrogen, this is closer in. This is + + align:start position:0% +in hydrogen, this is closer in. This is + + + align:start position:0% +in hydrogen, this is closer in. This is +closer in. This is closer in. Right? + + align:start position:0% +closer in. This is closer in. Right? + + + align:start position:0% +closer in. This is closer in. Right? +Make sense? + + align:start position:0% +Make sense? + + + align:start position:0% +Make sense? +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +But now also since I have this diagram + + align:start position:0% +But now also since I have this diagram + + + align:start position:0% +But now also since I have this diagram +up here on the board, I want to just uh + + align:start position:0% +up here on the board, I want to just uh + + + align:start position:0% +up here on the board, I want to just uh +convey an idea that you I think are + + align:start position:0% +convey an idea that you I think are + + + align:start position:0% +convey an idea that you I think are +already familiar with and that is this + + align:start position:0% +already familiar with and that is this + + + align:start position:0% +already familiar with and that is this +idea of shells. + + align:start position:0% +idea of shells. + + + align:start position:0% +idea of shells. +When you say a shell, you think of well + + align:start position:0% +When you say a shell, you think of well + + + align:start position:0% +When you say a shell, you think of well +the n=3 shell, the n equal2 shell, the n + + align:start position:0% +the n=3 shell, the n equal2 shell, the n + + + align:start position:0% +the n=3 shell, the n equal2 shell, the n +equal1 shell, right? But the word shell + + align:start position:0% +equal1 shell, right? But the word shell + + + align:start position:0% +equal1 shell, right? But the word shell +also conotes some spatial uh + + align:start position:0% +also conotes some spatial uh + + + align:start position:0% +also conotes some spatial uh +information, right? And you can see that + + align:start position:0% +information, right? And you can see that + + + align:start position:0% +information, right? And you can see that +spatial information here in this radial + + align:start position:0% +spatial information here in this radial + + + align:start position:0% +spatial information here in this radial +probability distribution function. What + + align:start position:0% +probability distribution function. What + + + align:start position:0% +probability distribution function. What +I want to point out is that the most + + align:start position:0% +I want to point out is that the most + + + align:start position:0% +I want to point out is that the most +probable value of r for the n=3 shell, + + align:start position:0% +probable value of r for the n=3 shell, + + + align:start position:0% +probable value of r for the n=3 shell, +well, those most probable values aren't + + align:start position:0% +well, those most probable values aren't + + + align:start position:0% +well, those most probable values aren't +identical for 3p and 3s, but they're + + align:start position:0% +identical for 3p and 3s, but they're + + + align:start position:0% +identical for 3p and 3s, but they're +very similar. They're similar compared + + align:start position:0% +very similar. They're similar compared + + + align:start position:0% +very similar. They're similar compared +to the most probable value for any + + align:start position:0% +to the most probable value for any + + + align:start position:0% +to the most probable value for any +electron in the n equal 2 shell. And + + align:start position:0% +electron in the n equal 2 shell. And + + + align:start position:0% +electron in the n equal 2 shell. And +those are similar than the most probable + + align:start position:0% +those are similar than the most probable + + + align:start position:0% +those are similar than the most probable +value for the electron in the 1s shell. + + align:start position:0% +value for the electron in the 1s shell. + + + align:start position:0% +value for the electron in the 1s shell. +So here you can see that spatial + + align:start position:0% +So here you can see that spatial + + + align:start position:0% +So here you can see that spatial +information. You can see that on the + + align:start position:0% +information. You can see that on the + + + align:start position:0% +information. You can see that on the +average the n=3 shell is further out + + align:start position:0% +average the n=3 shell is further out + + + align:start position:0% +average the n=3 shell is further out +from the nucleus than the n equal 2 + + align:start position:0% +from the nucleus than the n equal 2 + + + align:start position:0% +from the nucleus than the n equal 2 +shell than the n=1 shell. All right. So + + align:start position:0% +shell than the n=1 shell. All right. So + + + align:start position:0% +shell than the n=1 shell. All right. So +I just wanted to illustrate the concept + + align:start position:0% +I just wanted to illustrate the concept + + + align:start position:0% +I just wanted to illustrate the concept +of shells because we have that radial + + align:start position:0% +of shells because we have that radial + + + align:start position:0% +of shells because we have that radial +probability distribution function up + + align:start position:0% +probability distribution function up + + + align:start position:0% +probability distribution function up +here and it shows you kind of nicely how + + align:start position:0% +here and it shows you kind of nicely how + + + align:start position:0% +here and it shows you kind of nicely how +those shells are indeed separated in + + align:start position:0% +those shells are indeed separated in + + + align:start position:0% +those shells are indeed separated in +space on the average. All right, and + + align:start position:0% +space on the average. All right, and + + + align:start position:0% +space on the average. All right, and +that's important as we're going to see + + align:start position:0% +that's important as we're going to see + + + align:start position:0% +that's important as we're going to see +in a moment. Okay. + + align:start position:0% +in a moment. Okay. + + + align:start position:0% +in a moment. Okay. +Okay. So, that's a quick description of + + align:start position:0% +Okay. So, that's a quick description of + + + align:start position:0% +Okay. So, that's a quick description of +what the wave functions look like for + + align:start position:0% +what the wave functions look like for + + + align:start position:0% +what the wave functions look like for +the electrons in a multi-electron atom. + + align:start position:0% +the electrons in a multi-electron atom. + + + align:start position:0% +the electrons in a multi-electron atom. +They have the similar structure as the + + align:start position:0% +They have the similar structure as the + + + align:start position:0% +They have the similar structure as the +hydrogen atom wave functions. They're + + align:start position:0% +hydrogen atom wave functions. They're + + + align:start position:0% +hydrogen atom wave functions. They're +just all closer in because of the charge + + align:start position:0% +just all closer in because of the charge + + + align:start position:0% +just all closer in because of the charge +on the nucleus. + + align:start position:0% +on the nucleus. + + + align:start position:0% +on the nucleus. +All right. But now what we've got to do + + align:start position:0% +All right. But now what we've got to do + + + align:start position:0% +All right. But now what we've got to do +is that we have to look at the energies + + align:start position:0% +is that we have to look at the energies + + + align:start position:0% +is that we have to look at the energies +of the different states for these + + align:start position:0% +of the different states for these + + + align:start position:0% +of the different states for these +electrons. + + align:start position:0% + + + + align:start position:0% + +So we looked at the wave functions and + + align:start position:0% +So we looked at the wave functions and + + + align:start position:0% +So we looked at the wave functions and +now we got to talk about the energies. + + align:start position:0% +now we got to talk about the energies. + + + align:start position:0% +now we got to talk about the energies. +So here is that energy level diagram for + + align:start position:0% +So here is that energy level diagram for + + + align:start position:0% +So here is that energy level diagram for +the hydrogen atom that we drew uh a few + + align:start position:0% +the hydrogen atom that we drew uh a few + + + align:start position:0% +the hydrogen atom that we drew uh a few +days ago. + + align:start position:0% +days ago. + + + align:start position:0% +days ago. +You see that the n equal1 state here + + align:start position:0% +You see that the n equal1 state here + + + align:start position:0% +You see that the n equal1 state here +which is the 1s state is lowest in + + align:start position:0% +which is the 1s state is lowest in + + + align:start position:0% +which is the 1s state is lowest in +energy. The n equal2 state here is + + align:start position:0% +energy. The n equal2 state here is + + + align:start position:0% +energy. The n equal2 state here is +higher in energy. + + align:start position:0% +higher in energy. + + + align:start position:0% +higher in energy. +n equ= 3 n equal 4. And you see that we + + align:start position:0% +n equ= 3 n equal 4. And you see that we + + + align:start position:0% +n equ= 3 n equal 4. And you see that we +have four degenerate states at n equal + + align:start position:0% +have four degenerate states at n equal + + + align:start position:0% +have four degenerate states at n equal +2. That is the 2s state is the same + + align:start position:0% +2. That is the 2s state is the same + + + align:start position:0% +2. That is the 2s state is the same +energy as all the two p states. And at n + + align:start position:0% +energy as all the two p states. And at n + + + align:start position:0% +energy as all the two p states. And at n +equal 3 we got nine degenerate states. + + align:start position:0% +equal 3 we got nine degenerate states. + + + align:start position:0% +equal 3 we got nine degenerate states. +And at n equal 4 we got 16 degenerate + + align:start position:0% +And at n equal 4 we got 16 degenerate + + + align:start position:0% +And at n equal 4 we got 16 degenerate +states. Okay, + + align:start position:0% +states. Okay, + + + align:start position:0% +states. Okay, +but in a multi-electron atom that means + + align:start position:0% +but in a multi-electron atom that means + + + align:start position:0% +but in a multi-electron atom that means +starting with helium in a multi-electron + + align:start position:0% +starting with helium in a multi-electron + + + align:start position:0% +starting with helium in a multi-electron +atom things change. + + align:start position:0% +atom things change. + + + align:start position:0% +atom things change. +And the first big change is that all of + + align:start position:0% +And the first big change is that all of + + + align:start position:0% +And the first big change is that all of +these energies here are lower compared + + align:start position:0% +these energies here are lower compared + + + align:start position:0% +these energies here are lower compared +to the hydrogen atom. The energy of the + + align:start position:0% +to the hydrogen atom. The energy of the + + + align:start position:0% +to the hydrogen atom. The energy of the +1s state is lower than it is in the + + align:start position:0% +1s state is lower than it is in the + + + align:start position:0% +1s state is lower than it is in the +hydrogen atom. The 2s state is lower. + + align:start position:0% +hydrogen atom. The 2s state is lower. + + + align:start position:0% +hydrogen atom. The 2s state is lower. +The twop state is lower. The 3s state is + + align:start position:0% +The twop state is lower. The 3s state is + + + align:start position:0% +The twop state is lower. The 3s state is +lower. All of them are lower. Why do you + + align:start position:0% +lower. All of them are lower. Why do you + + + align:start position:0% +lower. All of them are lower. Why do you +think that's the case? + + align:start position:0% + + + + align:start position:0% + +Anybody? + + align:start position:0% + + + + align:start position:0% + +Pardon? + + align:start position:0% +Pardon? + + + align:start position:0% +Pardon? +It's closer to the nucleus. Yeah, it's + + align:start position:0% +It's closer to the nucleus. Yeah, it's + + + align:start position:0% +It's closer to the nucleus. Yeah, it's +closer to the nucleus because the coolum + + align:start position:0% +closer to the nucleus because the coolum + + + align:start position:0% +closer to the nucleus because the coolum +interaction is greater. Right. So that + + align:start position:0% +interaction is greater. Right. So that + + + align:start position:0% +interaction is greater. Right. So that +culum attraction is greater. That energy + + align:start position:0% +culum attraction is greater. That energy + + + align:start position:0% +culum attraction is greater. That energy +is greater. the binding energy is + + align:start position:0% +is greater. the binding energy is + + + align:start position:0% +is greater. the binding energy is +greater. It's more negative. All right? + + align:start position:0% +greater. It's more negative. All right? + + + align:start position:0% +greater. It's more negative. All right? +Same reason as the wave functions were + + align:start position:0% +Same reason as the wave functions were + + + align:start position:0% +Same reason as the wave functions were +in closer to the nucleus. Right? So + + align:start position:0% +in closer to the nucleus. Right? So + + + align:start position:0% +in closer to the nucleus. Right? So +these energies are lower because of the + + align:start position:0% +these energies are lower because of the + + + align:start position:0% +these energies are lower because of the +attraction that larger attraction + + align:start position:0% +attraction that larger attraction + + + align:start position:0% +attraction that larger attraction +because that nucleus is has a greater + + align:start position:0% +because that nucleus is has a greater + + + align:start position:0% +because that nucleus is has a greater +charge on it greater positive charge. + + align:start position:0% +charge on it greater positive charge. + + + align:start position:0% +charge on it greater positive charge. +All right. But the other thing that you + + align:start position:0% +All right. But the other thing that you + + + align:start position:0% +All right. But the other thing that you +see is that the 2s state has no longer + + align:start position:0% +see is that the 2s state has no longer + + + align:start position:0% +see is that the 2s state has no longer +the same energy as the 2p state. The 2s + + align:start position:0% +the same energy as the 2p state. The 2s + + + align:start position:0% +the same energy as the 2p state. The 2s +state is no longer degenerate with the + + align:start position:0% +state is no longer degenerate with the + + + align:start position:0% +state is no longer degenerate with the +2p state. + + align:start position:0% +2p state. + + + align:start position:0% +2p state. +And the 3s state is no longer degenerate + + align:start position:0% +And the 3s state is no longer degenerate + + + align:start position:0% +And the 3s state is no longer degenerate +with the 3p state. And the 3p state is + + align:start position:0% +with the 3p state. And the 3p state is + + + align:start position:0% +with the 3p state. And the 3p state is +no longer degenerate with the 3d state + + align:start position:0% +no longer degenerate with the 3d state + + + align:start position:0% +no longer degenerate with the 3d state +like it is in a hydrogen atom. So how + + align:start position:0% +like it is in a hydrogen atom. So how + + + align:start position:0% +like it is in a hydrogen atom. So how +are we going to uh understand that? All + + align:start position:0% +are we going to uh understand that? All + + + align:start position:0% +are we going to uh understand that? All +right. Why is this degeneracy broken or + + align:start position:0% +right. Why is this degeneracy broken or + + + align:start position:0% +right. Why is this degeneracy broken or +lifted as it's sometimes uh called? + + align:start position:0% +lifted as it's sometimes uh called? + + + align:start position:0% +lifted as it's sometimes uh called? +Well, to explain that, what I'm going to + + align:start position:0% +Well, to explain that, what I'm going to + + + align:start position:0% +Well, to explain that, what I'm going to +have to do here is to talk about a + + align:start position:0% +have to do here is to talk about a + + + align:start position:0% +have to do here is to talk about a +concept called shielding. + + align:start position:0% +concept called shielding. + + + align:start position:0% +concept called shielding. +And shielding then is what uh that + + align:start position:0% +And shielding then is what uh that + + + align:start position:0% +And shielding then is what uh that +affects or or or creates what we call an + + align:start position:0% +affects or or or creates what we call an + + + align:start position:0% +affects or or or creates what we call an +effective charge that we're going to + + align:start position:0% +effective charge that we're going to + + + align:start position:0% +effective charge that we're going to +talk about. + + align:start position:0% + + + + align:start position:0% + +Now to do so I want to point out this + + align:start position:0% +Now to do so I want to point out this + + + align:start position:0% +Now to do so I want to point out this +that all of these binding energies right + + align:start position:0% +that all of these binding energies right + + + align:start position:0% +that all of these binding energies right +here these binding energies E subm E + + align:start position:0% +here these binding energies E subm E + + + align:start position:0% +here these binding energies E subm E +subn but now it's E subn L it depends on + + align:start position:0% +subn but now it's E subn L it depends on + + + align:start position:0% +subn but now it's E subn L it depends on +the angular momentum quantum number + + align:start position:0% +the angular momentum quantum number + + + align:start position:0% +the angular momentum quantum number +right those binding energies are minus + + align:start position:0% +right those binding energies are minus + + + align:start position:0% +right those binding energies are minus +the ionization energy + + align:start position:0% +the ionization energy + + + align:start position:0% +the ionization energy +right of the electron in that NL state + + align:start position:0% +right of the electron in that NL state + + + align:start position:0% +right of the electron in that NL state +that's the physical significance of that + + align:start position:0% +that's the physical significance of that + + + align:start position:0% +that's the physical significance of that +but what we're going to do here is that + + align:start position:0% +but what we're going to do here is that + + + align:start position:0% +but what we're going to do here is that +we're going to + + align:start position:0% +we're going to + + + align:start position:0% +we're going to +uh set that energy that binding energy + + align:start position:0% +uh set that energy that binding energy + + + align:start position:0% +uh set that energy that binding energy +equal to this + + align:start position:0% +equal to this + + + align:start position:0% +equal to this +this effective z^2 r subh n squ all + + align:start position:0% +this effective z^2 r subh n squ all + + + align:start position:0% +this effective z^2 r subh n squ all +right and now I'm going to switch to the + + align:start position:0% +right and now I'm going to switch to the + + + align:start position:0% +right and now I'm going to switch to the +board and um we'll talk about that a + + align:start position:0% +board and um we'll talk about that a + + + align:start position:0% +board and um we'll talk about that a +little bit and explain this effective + + align:start position:0% +little bit and explain this effective + + + align:start position:0% +little bit and explain this effective +charge and the shielding so that we can + + align:start position:0% +charge and the shielding so that we can + + + align:start position:0% +charge and the shielding so that we can +understand by the uh so that we can + + align:start position:0% +understand by the uh so that we can + + + align:start position:0% +understand by the uh so that we can +understand why the um 2s state is lower + + align:start position:0% +understand why the um 2s state is lower + + + align:start position:0% +understand why the um 2s state is lower +in energy than the 2p state. + + align:start position:0% + + + + align:start position:0% + +Okay. So I just said these states E + + align:start position:0% +Okay. So I just said these states E + + + align:start position:0% +Okay. So I just said these states E +subnl + + align:start position:0% +subnl + + + align:start position:0% +subnl +physically significant is that they are + + align:start position:0% +physically significant is that they are + + + align:start position:0% +physically significant is that they are +minus the ionization energy right + + align:start position:0% +minus the ionization energy right + + + align:start position:0% +minus the ionization energy right +and I'm going to approximate + + align:start position:0% +and I'm going to approximate + + + align:start position:0% +and I'm going to approximate +that binding energy as a hydrogen atom + + align:start position:0% +that binding energy as a hydrogen atom + + + align:start position:0% +that binding energy as a hydrogen atom +binding energy in the sense that I'm + + align:start position:0% +binding energy in the sense that I'm + + + align:start position:0% +binding energy in the sense that I'm +going to make that set that equal to + + align:start position:0% +going to make that set that equal to + + + align:start position:0% +going to make that set that equal to +that RBER constant R subH H over N2 and + + align:start position:0% +that RBER constant R subH H over N2 and + + + align:start position:0% +that RBER constant R subH H over N2 and +this is minus. + + align:start position:0% +this is minus. + + + align:start position:0% +this is minus. +But out here I'm going to put a Z. But + + align:start position:0% +But out here I'm going to put a Z. But + + + align:start position:0% +But out here I'm going to put a Z. But +this Z is not going to be the charge on + + align:start position:0% +this Z is not going to be the charge on + + + align:start position:0% +this Z is not going to be the charge on +the nucleus, but rather it's going to be + + align:start position:0% +the nucleus, but rather it's going to be + + + align:start position:0% +the nucleus, but rather it's going to be +something called the effective charge. + + align:start position:0% +something called the effective charge. + + + align:start position:0% +something called the effective charge. +So Z E FF and it's going to depend on + + align:start position:0% +So Z E FF and it's going to depend on + + + align:start position:0% +So Z E FF and it's going to depend on +both N and L quantum numbers. + + align:start position:0% +both N and L quantum numbers. + + + align:start position:0% +both N and L quantum numbers. +This I'm calling the effective charge. + + align:start position:0% + + + + align:start position:0% + +Okay. And what I'm going to do + + align:start position:0% +Okay. And what I'm going to do + + + align:start position:0% +Okay. And what I'm going to do +eventually here + + align:start position:0% +eventually here + + + align:start position:0% +eventually here +is to use the experimentally measured + + align:start position:0% +is to use the experimentally measured + + + align:start position:0% +is to use the experimentally measured +ionization energies + + align:start position:0% +ionization energies + + + align:start position:0% +ionization energies +to back out an effective charge for each + + align:start position:0% +to back out an effective charge for each + + + align:start position:0% +to back out an effective charge for each +electron in each n subl state. That's + + align:start position:0% +electron in each n subl state. That's + + + align:start position:0% +electron in each n subl state. That's +what I'm going to do. + + align:start position:0% +what I'm going to do. + + + align:start position:0% +what I'm going to do. +All right. But now what is this + + align:start position:0% +All right. But now what is this + + + align:start position:0% +All right. But now what is this +effective charge? + + align:start position:0% +effective charge? + + + align:start position:0% +effective charge? +Well, suppose I take a helium atom and + + align:start position:0% +Well, suppose I take a helium atom and + + + align:start position:0% +Well, suppose I take a helium atom and +we have a nucleus here and the charge on + + align:start position:0% +we have a nucleus here and the charge on + + + align:start position:0% +we have a nucleus here and the charge on +that nucleus is plus two + + align:start position:0% +that nucleus is plus two + + + align:start position:0% +that nucleus is plus two +and of course helium has two electrons + + align:start position:0% +and of course helium has two electrons + + + align:start position:0% +and of course helium has two electrons +and so I have say an electron number one + + align:start position:0% +and so I have say an electron number one + + + align:start position:0% +and so I have say an electron number one +over here and I have electron number two + + align:start position:0% +over here and I have electron number two + + + align:start position:0% +over here and I have electron number two +over here. Okay. + + align:start position:0% +over here. Okay. + + + align:start position:0% +over here. Okay. +But the bottom line is that for this + + align:start position:0% +But the bottom line is that for this + + + align:start position:0% +But the bottom line is that for this +electron one right over here, + + align:start position:0% +electron one right over here, + + + align:start position:0% +electron one right over here, +this electron one does not experience + + align:start position:0% +this electron one does not experience + + + align:start position:0% +this electron one does not experience +the full nuclear charge. + + align:start position:0% +the full nuclear charge. + + + align:start position:0% +the full nuclear charge. +Why? Because on the average there's + + align:start position:0% +Why? Because on the average there's + + + align:start position:0% +Why? Because on the average there's +another electron in between it and the + + align:start position:0% +another electron in between it and the + + + align:start position:0% +another electron in between it and the +nucleus. + + align:start position:0% +nucleus. + + + align:start position:0% +nucleus. +And so the charge, the nuclear charge + + align:start position:0% +And so the charge, the nuclear charge + + + align:start position:0% +And so the charge, the nuclear charge +that's experienced by this electron is + + align:start position:0% +that's experienced by this electron is + + + align:start position:0% +that's experienced by this electron is +actually lower than the full nuclear + + align:start position:0% +actually lower than the full nuclear + + + align:start position:0% +actually lower than the full nuclear +charge because this electron here is + + align:start position:0% +charge because this electron here is + + + align:start position:0% +charge because this electron here is +negatively charged and it in effect + + align:start position:0% +negatively charged and it in effect + + + align:start position:0% +negatively charged and it in effect +cancels part of this positive charge on + + align:start position:0% +cancels part of this positive charge on + + + align:start position:0% +cancels part of this positive charge on +the nucleus. + + align:start position:0% +the nucleus. + + + align:start position:0% +the nucleus. +And so this electron doesn't experience + + align:start position:0% +And so this electron doesn't experience + + + align:start position:0% +And so this electron doesn't experience +the full nuclear charge. it experiences + + align:start position:0% +the full nuclear charge. it experiences + + + align:start position:0% +the full nuclear charge. it experiences +something smaller than the full nuclear + + align:start position:0% +something smaller than the full nuclear + + + align:start position:0% +something smaller than the full nuclear +charge. + + align:start position:0% +charge. + + + align:start position:0% +charge. +And that charge that something smaller + + align:start position:0% +And that charge that something smaller + + + align:start position:0% +And that charge that something smaller +than the full nuclear charge is what we + + align:start position:0% +than the full nuclear charge is what we + + + align:start position:0% +than the full nuclear charge is what we +call the effective charge. All right. + + align:start position:0% +call the effective charge. All right. + + + align:start position:0% +call the effective charge. All right. +So, how are we going to determine that + + align:start position:0% +So, how are we going to determine that + + + align:start position:0% +So, how are we going to determine that +effective charge? Well, we're going to + + align:start position:0% +effective charge? Well, we're going to + + + align:start position:0% +effective charge? Well, we're going to +use some experimental measurements to do + + align:start position:0% +use some experimental measurements to do + + + align:start position:0% +use some experimental measurements to do +that. + + align:start position:0% +that. + + + align:start position:0% +that. +We're going to look up the ionization + + align:start position:0% +We're going to look up the ionization + + + align:start position:0% +We're going to look up the ionization +energies or measure the ionization + + align:start position:0% +energies or measure the ionization + + + align:start position:0% +energies or measure the ionization +energies and we'll see how we do that a + + align:start position:0% +energies and we'll see how we do that a + + + align:start position:0% +energies and we'll see how we do that a +little bit later, but you can guess how + + align:start position:0% +little bit later, but you can guess how + + + align:start position:0% +little bit later, but you can guess how +we do that. We're going to look them up + + align:start position:0% +we do that. We're going to look them up + + + align:start position:0% +we do that. We're going to look them up +and we're going to back out the + + align:start position:0% +and we're going to back out the + + + align:start position:0% +and we're going to back out the +effective charge. All right. So, let's + + align:start position:0% +effective charge. All right. So, let's + + + align:start position:0% +effective charge. All right. So, let's +do that for a um let's do that for + + align:start position:0% +do that for a um let's do that for + + + align:start position:0% +do that for a um let's do that for +helium. + + align:start position:0% +helium. + + + align:start position:0% +helium. +If you go and you look up the ionization + + align:start position:0% +If you go and you look up the ionization + + + align:start position:0% +If you go and you look up the ionization +energy for a helium atom, you find that + + align:start position:0% +energy for a helium atom, you find that + + + align:start position:0% +energy for a helium atom, you find that +it is 3.94* + + align:start position:0% + + + + align:start position:0% + +10 -8 jewels. + + align:start position:0% + + + + align:start position:0% + +So what I can do is I can rearrange that + + align:start position:0% +So what I can do is I can rearrange that + + + align:start position:0% +So what I can do is I can rearrange that +equation for the effective charge Z E FF + + align:start position:0% +equation for the effective charge Z E FF + + + align:start position:0% +equation for the effective charge Z E FF +and it's N= 1 L= Z right + + align:start position:0% +and it's N= 1 L= Z right + + + align:start position:0% +and it's N= 1 L= Z right +and that will be N2 + + align:start position:0% +and that will be N2 + + + align:start position:0% +and that will be N2 +times that ionization energy + + align:start position:0% +times that ionization energy + + + align:start position:0% +times that ionization energy +over r subh + + align:start position:0% +over r subh + + + align:start position:0% +over r subh +all to the 12. + + align:start position:0% +all to the 12. + + + align:start position:0% +all to the 12. +The ionization energy when we talk about + + align:start position:0% +The ionization energy when we talk about + + + align:start position:0% +The ionization energy when we talk about +ionization energy it's usually from the + + align:start position:0% +ionization energy it's usually from the + + + align:start position:0% +ionization energy it's usually from the +ground state. So n is going to be equal + + align:start position:0% +ground state. So n is going to be equal + + + align:start position:0% +ground state. So n is going to be equal +to 1 here. All right. The ionization + + align:start position:0% +to 1 here. All right. The ionization + + + align:start position:0% +to 1 here. All right. The ionization +energy I just said was 3.94 * 10 -18 + + align:start position:0% +energy I just said was 3.94 * 10 -18 + + + align:start position:0% +energy I just said was 3.94 * 10 -18 +juw. Ridberg's constant in jewels is + + align:start position:0% +juw. Ridberg's constant in jewels is + + + align:start position:0% +juw. Ridberg's constant in jewels is +2.180* + + align:start position:0% +2.180* + + + align:start position:0% +2.180* +10 the minus8 jewels. Hey if I solve + + align:start position:0% +10 the minus8 jewels. Hey if I solve + + + align:start position:0% +10 the minus8 jewels. Hey if I solve +that I find the effective charge is 1.34 + + align:start position:0% +that I find the effective charge is 1.34 + + + align:start position:0% +that I find the effective charge is 1.34 +plus okay so the charge on the helium + + align:start position:0% +plus okay so the charge on the helium + + + align:start position:0% +plus okay so the charge on the helium +nucleus is + two but the effective + + align:start position:0% +nucleus is + two but the effective + + + align:start position:0% +nucleus is + two but the effective +charge for those electrons in the helium + + align:start position:0% +charge for those electrons in the helium + + + align:start position:0% +charge for those electrons in the helium +is less than that it's 1.34. + + align:start position:0% +is less than that it's 1.34. + + + align:start position:0% +is less than that it's 1.34. +Why? because on the average there is + + align:start position:0% +Why? because on the average there is + + + align:start position:0% +Why? because on the average there is +another electron in between that + + align:start position:0% +another electron in between that + + + align:start position:0% +another electron in between that +electron and the nucleus and so the full + + align:start position:0% +electron and the nucleus and so the full + + + align:start position:0% +electron and the nucleus and so the full +nuclear charge isn't experienced. That's + + align:start position:0% +nuclear charge isn't experienced. That's + + + align:start position:0% +nuclear charge isn't experienced. That's +the effective charge. + + align:start position:0% +the effective charge. + + + align:start position:0% +the effective charge. +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +So now this effective charge and and the + + align:start position:0% +So now this effective charge and and the + + + align:start position:0% +So now this effective charge and and the +physical + + align:start position:0% +physical + + + align:start position:0% +physical +concept here of shielding that's what's + + align:start position:0% +concept here of shielding that's what's + + + align:start position:0% +concept here of shielding that's what's +so important in why the energy of the 2s + + align:start position:0% +so important in why the energy of the 2s + + + align:start position:0% +so important in why the energy of the 2s +state is lower than the energy of the 2p + + align:start position:0% +state is lower than the energy of the 2p + + + align:start position:0% +state is lower than the energy of the 2p +state. All right. So the energy of 2s + + align:start position:0% +state. All right. So the energy of 2s + + + align:start position:0% +state. All right. So the energy of 2s +the 2s state an electron in the 2s state + + align:start position:0% +the 2s state an electron in the 2s state + + + align:start position:0% +the 2s state an electron in the 2s state +is more strongly bound than in the 2p + + align:start position:0% +is more strongly bound than in the 2p + + + align:start position:0% +is more strongly bound than in the 2p +state. Right? that energy is lower than + + align:start position:0% +state. Right? that energy is lower than + + + align:start position:0% +state. Right? that energy is lower than +the 2p state. Why is that the case? + + align:start position:0% +the 2p state. Why is that the case? + + + align:start position:0% +the 2p state. Why is that the case? +Well, let's think of the lithium atom. + + align:start position:0% +Well, let's think of the lithium atom. + + + align:start position:0% +Well, let's think of the lithium atom. +All right, you know that the electron + + align:start position:0% +All right, you know that the electron + + + align:start position:0% +All right, you know that the electron +configuration of lithium is 1 s2 2 s1. + + align:start position:0% +configuration of lithium is 1 s2 2 s1. + + + align:start position:0% +configuration of lithium is 1 s2 2 s1. +The electron configuration of lithium is + + align:start position:0% +The electron configuration of lithium is + + + align:start position:0% +The electron configuration of lithium is +not 1 s2 2 p1, right? Because that's a + + align:start position:0% +not 1 s2 2 p1, right? Because that's a + + + align:start position:0% +not 1 s2 2 p1, right? Because that's a +higher energy. But why? + + align:start position:0% +higher energy. But why? + + + align:start position:0% +higher energy. But why? +Well, to answer that, we've got to look + + align:start position:0% +Well, to answer that, we've got to look + + + align:start position:0% +Well, to answer that, we've got to look +at a radial probability distribution + + align:start position:0% +at a radial probability distribution + + + align:start position:0% +at a radial probability distribution +again. + + align:start position:0% +again. + + + align:start position:0% +again. +And I'm going to draw it for the 2s + + align:start position:0% +And I'm going to draw it for the 2s + + + align:start position:0% +And I'm going to draw it for the 2s +state. + + align:start position:0% +state. + + + align:start position:0% +state. +So, here it is for the 2s state, right? + + align:start position:0% +So, here it is for the 2s state, right? + + + align:start position:0% +So, here it is for the 2s state, right? +And I'm going to draw it for the 2p + + align:start position:0% +And I'm going to draw it for the 2p + + + align:start position:0% +And I'm going to draw it for the 2p +state. So, here it is for the 2p state. + + align:start position:0% +state. So, here it is for the 2p state. + + + align:start position:0% +state. So, here it is for the 2p state. +All right. So, this is 2 p. + + align:start position:0% +All right. So, this is 2 p. + + + align:start position:0% +All right. So, this is 2 p. +And this is 2s. + + align:start position:0% +And this is 2s. + + + align:start position:0% +And this is 2s. +All right. + + align:start position:0% +All right. + + + align:start position:0% +All right. +Now we have to do a thought experiment + + align:start position:0% +Now we have to do a thought experiment + + + align:start position:0% +Now we have to do a thought experiment +here. And that is this. If you look at + + align:start position:0% +here. And that is this. If you look at + + + align:start position:0% +here. And that is this. If you look at +the 2s radial probability distribution + + align:start position:0% +the 2s radial probability distribution + + + align:start position:0% +the 2s radial probability distribution +function, + + align:start position:0% +function, + + + align:start position:0% +function, +there is a part of this distribution + + align:start position:0% +there is a part of this distribution + + + align:start position:0% +there is a part of this distribution +function that is really close to the + + align:start position:0% +function that is really close to the + + + align:start position:0% +function that is really close to the +nucleus. + + align:start position:0% +nucleus. + + + align:start position:0% +nucleus. +And for the sake of this argument, let + + align:start position:0% +And for the sake of this argument, let + + + align:start position:0% +And for the sake of this argument, let +me say that for this part of the radial + + align:start position:0% +me say that for this part of the radial + + + align:start position:0% +me say that for this part of the radial +probability distribution function, + + align:start position:0% +probability distribution function, + + + align:start position:0% +probability distribution function, +the effective nuclear charge is plus + + align:start position:0% +the effective nuclear charge is plus + + + align:start position:0% +the effective nuclear charge is plus +three. All right. Now, that's of course + + align:start position:0% +three. All right. Now, that's of course + + + align:start position:0% +three. All right. Now, that's of course +not the case, but bear with me for a + + align:start position:0% +not the case, but bear with me for a + + + align:start position:0% +not the case, but bear with me for a +moment. Okay. We're saying for this part + + align:start position:0% +moment. Okay. We're saying for this part + + + align:start position:0% +moment. Okay. We're saying for this part +of the radial probability distribution + + align:start position:0% +of the radial probability distribution + + + align:start position:0% +of the radial probability distribution +function, the effective charge is plus + + align:start position:0% +function, the effective charge is plus + + + align:start position:0% +function, the effective charge is plus +three. Well, that is the nuclear charge, + + align:start position:0% +three. Well, that is the nuclear charge, + + + align:start position:0% +three. Well, that is the nuclear charge, +but we're saying it's close enough. + + align:start position:0% +but we're saying it's close enough. + + + align:start position:0% +but we're saying it's close enough. +We'll just call it plus three. + + align:start position:0% +We'll just call it plus three. + + + align:start position:0% +We'll just call it plus three. +However, for this part of the radial + + align:start position:0% +However, for this part of the radial + + + align:start position:0% +However, for this part of the radial +probability distribution function here + + align:start position:0% +probability distribution function here + + + align:start position:0% +probability distribution function here +for the 2s, + + align:start position:0% +for the 2s, + + + align:start position:0% +for the 2s, +we're going to say the effective charge + + align:start position:0% +we're going to say the effective charge + + + align:start position:0% +we're going to say the effective charge +Z FF, we're going to say that's plus one + + align:start position:0% +Z FF, we're going to say that's plus one + + + align:start position:0% +Z FF, we're going to say that's plus one +plus one E and plus three E here. All + + align:start position:0% +plus one E and plus three E here. All + + + align:start position:0% +plus one E and plus three E here. All +right. Why? Well, because in lithium + + align:start position:0% +right. Why? Well, because in lithium + + + align:start position:0% +right. Why? Well, because in lithium +there are these 1s electrons that are + + align:start position:0% +there are these 1s electrons that are + + + align:start position:0% +there are these 1s electrons that are +really close in here and we're going to + + align:start position:0% +really close in here and we're going to + + + align:start position:0% +really close in here and we're going to +say that those 2s electrons + + align:start position:0% +say that those 2s electrons + + + align:start position:0% +say that those 2s electrons +screen completely the nuclear charge. So + + align:start position:0% +screen completely the nuclear charge. So + + + align:start position:0% +screen completely the nuclear charge. So +if you've got so you've got a Z equ= + + + align:start position:0% +if you've got so you've got a Z equ= + + + + align:start position:0% +if you've got so you've got a Z equ= + +three and you've got two electrons here + + align:start position:0% +three and you've got two electrons here + + + align:start position:0% +three and you've got two electrons here +electron + + align:start position:0% +electron + + + align:start position:0% +electron +got electron one and electron two and + + align:start position:0% +got electron one and electron two and + + + align:start position:0% +got electron one and electron two and +you got this electron number three out + + align:start position:0% +you got this electron number three out + + + align:start position:0% +you got this electron number three out +here right since this is a minus one and + + align:start position:0% +here right since this is a minus one and + + + align:start position:0% +here right since this is a minus one and +this is a minus one the effective charge + + align:start position:0% +this is a minus one the effective charge + + + align:start position:0% +this is a minus one the effective charge +here for this way out electron hey + + align:start position:0% +here for this way out electron hey + + + align:start position:0% +here for this way out electron hey +that's going to be plus one + + align:start position:0% +that's going to be plus one + + + align:start position:0% +that's going to be plus one +okay but now what about the 2p state if + + align:start position:0% +okay but now what about the 2p state if + + + align:start position:0% +okay but now what about the 2p state if +we had an electron in that 2p state. + + align:start position:0% +we had an electron in that 2p state. + + + align:start position:0% +we had an electron in that 2p state. +Well, what you can see is that because + + align:start position:0% +Well, what you can see is that because + + + align:start position:0% +Well, what you can see is that because +the most probable value of r of the 2p + + align:start position:0% +the most probable value of r of the 2p + + + align:start position:0% +the most probable value of r of the 2p +state isn't about the same place as it + + align:start position:0% +state isn't about the same place as it + + + align:start position:0% +state isn't about the same place as it +is for the 2s state. It's not exactly + + align:start position:0% +is for the 2s state. It's not exactly + + + align:start position:0% +is for the 2s state. It's not exactly +the same. It's actually a little closer + + align:start position:0% +the same. It's actually a little closer + + + align:start position:0% +the same. It's actually a little closer +in, but it's about the same place. We're + + align:start position:0% +in, but it's about the same place. We're + + + align:start position:0% +in, but it's about the same place. We're +going to say that for an electron in the + + align:start position:0% +going to say that for an electron in the + + + align:start position:0% +going to say that for an electron in the +2p state, + + align:start position:0% +2p state, + + + align:start position:0% +2p state, +the effective nuclear charge is going to + + align:start position:0% +the effective nuclear charge is going to + + + align:start position:0% +the effective nuclear charge is going to +be one. + + align:start position:0% +be one. + + + align:start position:0% +be one. +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +Okay. But now, in order to + + align:start position:0% +Okay. But now, in order to + + + align:start position:0% +Okay. But now, in order to +calculate or think about the total + + align:start position:0% +calculate or think about the total + + + align:start position:0% +calculate or think about the total +effective nuclear charge, what we're + + align:start position:0% +effective nuclear charge, what we're + + + align:start position:0% +effective nuclear charge, what we're +going to have to do is to average that + + align:start position:0% +going to have to do is to average that + + + align:start position:0% +going to have to do is to average that +effective charge over these probability + + align:start position:0% +effective charge over these probability + + + align:start position:0% +effective charge over these probability +distributions. + + align:start position:0% +distributions. + + + align:start position:0% +distributions. +So if the 2s probability distribution + + align:start position:0% +So if the 2s probability distribution + + + align:start position:0% +So if the 2s probability distribution +has a part of it where the effective + + align:start position:0% +has a part of it where the effective + + + align:start position:0% +has a part of it where the effective +charge is + three and part of it where + + align:start position:0% +charge is + three and part of it where + + + align:start position:0% +charge is + three and part of it where +it is + one, if I average over that, + + align:start position:0% +it is + one, if I average over that, + + + align:start position:0% +it is + one, if I average over that, +well the effective charge is going to + + align:start position:0% +well the effective charge is going to + + + align:start position:0% +well the effective charge is going to +be, I don't know, plus two or something. + + align:start position:0% +be, I don't know, plus two or something. + + + align:start position:0% +be, I don't know, plus two or something. +But for the 2pwave function where the + + align:start position:0% +But for the 2pwave function where the + + + align:start position:0% +But for the 2pwave function where the +effective charge is all plus one, it + + align:start position:0% +effective charge is all plus one, it + + + align:start position:0% +effective charge is all plus one, it +doesn't have this lobe that's really + + align:start position:0% +doesn't have this lobe that's really + + + align:start position:0% +doesn't have this lobe that's really +close to the nucleus where the effective + + align:start position:0% +close to the nucleus where the effective + + + align:start position:0% +close to the nucleus where the effective +charge is large. + + align:start position:0% +charge is large. + + + align:start position:0% +charge is large. +Well, that effective charge for the 2p + + align:start position:0% +Well, that effective charge for the 2p + + + align:start position:0% +Well, that effective charge for the 2p +is going to be smaller than it is for + + align:start position:0% +is going to be smaller than it is for + + + align:start position:0% +is going to be smaller than it is for +the 2s. All right. So, on the average + + align:start position:0% +the 2s. All right. So, on the average + + + align:start position:0% +the 2s. All right. So, on the average +here, + + align:start position:0% +here, + + + align:start position:0% +here, +the uh the the effective charge + + align:start position:0% +the uh the the effective charge + + + align:start position:0% +the uh the the effective charge +zf + + align:start position:0% +zf + + + align:start position:0% +zf +for the 2s + + align:start position:0% +for the 2s + + + align:start position:0% +for the 2s +is going to be greater than zf + + align:start position:0% +is going to be greater than zf + + + align:start position:0% +is going to be greater than zf +for the 2p electron. + + align:start position:0% +for the 2p electron. + + + align:start position:0% +for the 2p electron. +Since that effective charge is greater, + + align:start position:0% +Since that effective charge is greater, + + + align:start position:0% +Since that effective charge is greater, +well, we showed right up here, right, + + align:start position:0% +well, we showed right up here, right, + + + align:start position:0% +well, we showed right up here, right, +that the binding energy therefore is + + align:start position:0% +that the binding energy therefore is + + + align:start position:0% +that the binding energy therefore is +going to be more negative because that Z + + align:start position:0% +going to be more negative because that Z + + + align:start position:0% +going to be more negative because that Z +is larger. All right? + + align:start position:0% +is larger. All right? + + + align:start position:0% +is larger. All right? +And so that's why the 2s state is lower + + align:start position:0% +And so that's why the 2s state is lower + + + align:start position:0% +And so that's why the 2s state is lower +in energy than the 2p and so on and so + + align:start position:0% +in energy than the 2p and so on and so + + + align:start position:0% +in energy than the 2p and so on and so +forth. Two uh three 3p is lower than 3d + + align:start position:0% +forth. Two uh three 3p is lower than 3d + + + align:start position:0% +forth. Two uh three 3p is lower than 3d +etc etc. Okay, make sense? + + align:start position:0% +etc etc. Okay, make sense? + + + align:start position:0% +etc etc. Okay, make sense? +Okay, it's because of this phenomena of + + align:start position:0% +Okay, it's because of this phenomena of + + + align:start position:0% +Okay, it's because of this phenomena of +shielding and because the 2s wave + + align:start position:0% +shielding and because the 2s wave + + + align:start position:0% +shielding and because the 2s wave +function always has this probability of + + align:start position:0% +function always has this probability of + + + align:start position:0% +function always has this probability of +the electrons being really close to the + + align:start position:0% +the electrons being really close to the + + + align:start position:0% +the electrons being really close to the +nucleus where the effective nuclear + + align:start position:0% +nucleus where the effective nuclear + + + align:start position:0% +nucleus where the effective nuclear +charge is larger. If you average the + + align:start position:0% +charge is larger. If you average the + + + align:start position:0% +charge is larger. If you average the +nuclear charge over the probability + + align:start position:0% +nuclear charge over the probability + + + align:start position:0% +nuclear charge over the probability +distributions, well, the effective + + align:start position:0% +distributions, well, the effective + + + align:start position:0% +distributions, well, the effective +charge + + align:start position:0% +charge + + + align:start position:0% +charge +for that 2s wave function is always + + align:start position:0% +for that 2s wave function is always + + + align:start position:0% +for that 2s wave function is always +going to be larger than the 2p wave + + align:start position:0% +going to be larger than the 2p wave + + + align:start position:0% +going to be larger than the 2p wave +function. So therefore, the 2s is lower + + align:start position:0% +function. So therefore, the 2s is lower + + + align:start position:0% +function. So therefore, the 2s is lower +in energy than the 3p. + + align:start position:0% +in energy than the 3p. + + + align:start position:0% +in energy than the 3p. +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +Okay, that is an important point. + + align:start position:0% + + + + align:start position:0% + +Okay. So now + + align:start position:0% + + + + align:start position:0% + +how do we actually write the electron + + align:start position:0% +how do we actually write the electron + + + align:start position:0% +how do we actually write the electron +configurations for all of the atoms in + + align:start position:0% +configurations for all of the atoms in + + + align:start position:0% +configurations for all of the atoms in +the periodic table? + + align:start position:0% +the periodic table? + + + align:start position:0% +the periodic table? +Well, I think that you already know that + + align:start position:0% +Well, I think that you already know that + + + align:start position:0% +Well, I think that you already know that +we use something called the alpha + + align:start position:0% +we use something called the alpha + + + align:start position:0% +we use something called the alpha +principle. + + align:start position:0% +principle. + + + align:start position:0% +principle. +And the alpha principle is called is the + + align:start position:0% +And the alpha principle is called is the + + + align:start position:0% +And the alpha principle is called is the +building up principle. + + align:start position:0% +building up principle. + + + align:start position:0% +building up principle. +And what that says is that you make a + + align:start position:0% +And what that says is that you make a + + + align:start position:0% +And what that says is that you make a +list here of the states and you order + + align:start position:0% +list here of the states and you order + + + align:start position:0% +list here of the states and you order +the states + + align:start position:0% +the states + + + align:start position:0% +the states +according to their energy. the lowest + + align:start position:0% +according to their energy. the lowest + + + align:start position:0% +according to their energy. the lowest +energy at the bottom here and then keep + + align:start position:0% +energy at the bottom here and then keep + + + align:start position:0% +energy at the bottom here and then keep +on going and we'll talk about we'll talk + + align:start position:0% +on going and we'll talk about we'll talk + + + align:start position:0% +on going and we'll talk about we'll talk +about the uh energies of these states in + + align:start position:0% +about the uh energies of these states in + + + align:start position:0% +about the uh energies of these states in +a moment. + + align:start position:0% +a moment. + + + align:start position:0% +a moment. +But then in order to write the electron + + align:start position:0% +But then in order to write the electron + + + align:start position:0% +But then in order to write the electron +configuration you start putting in + + align:start position:0% +configuration you start putting in + + + align:start position:0% +configuration you start putting in +electrons into these states one electron + + align:start position:0% +electrons into these states one electron + + + align:start position:0% +electrons into these states one electron +at a time starting with the lowest + + align:start position:0% +at a time starting with the lowest + + + align:start position:0% +at a time starting with the lowest +energy state. So for hydrogen well that + + align:start position:0% +energy state. So for hydrogen well that + + + align:start position:0% +energy state. So for hydrogen well that +electron configuration is 1 s. + + align:start position:0% +electron configuration is 1 s. + + + align:start position:0% +electron configuration is 1 s. +for helium. Well, that electron + + align:start position:0% +for helium. Well, that electron + + + align:start position:0% +for helium. Well, that electron +configuration is going to be 1 s + + align:start position:0% +configuration is going to be 1 s + + + align:start position:0% +configuration is going to be 1 s +squared. But you already know that we + + align:start position:0% +squared. But you already know that we + + + align:start position:0% +squared. But you already know that we +have to put in that second electron + + align:start position:0% +have to put in that second electron + + + align:start position:0% +have to put in that second electron +obeying the poly exclusion principle. + + align:start position:0% +obeying the poly exclusion principle. + + + align:start position:0% +obeying the poly exclusion principle. +So, we're going to fill up these states + + align:start position:0% +So, we're going to fill up these states + + + align:start position:0% +So, we're going to fill up these states +one electron at a time, lowest energy + + align:start position:0% +one electron at a time, lowest energy + + + align:start position:0% +one electron at a time, lowest energy +first and then keep going to the next + + align:start position:0% +first and then keep going to the next + + + align:start position:0% +first and then keep going to the next +higher energy level. And we're going to + + align:start position:0% +higher energy level. And we're going to + + + align:start position:0% +higher energy level. And we're going to +do so heating the power exclusion + + align:start position:0% +do so heating the power exclusion + + + align:start position:0% +do so heating the power exclusion +principle as we go. All right. So that's + + align:start position:0% +principle as we go. All right. So that's + + + align:start position:0% +principle as we go. All right. So that's +helium. Here's lithium. All right. Now + + align:start position:0% +helium. Here's lithium. All right. Now + + + align:start position:0% +helium. Here's lithium. All right. Now +we got lithium. We're going to do + + align:start position:0% +we got lithium. We're going to do + + + align:start position:0% +we got lithium. We're going to do +burillium. Well, we have to heed the + + align:start position:0% +burillium. Well, we have to heed the + + + align:start position:0% +burillium. Well, we have to heed the +poly exclusion principle. Right. So that + + align:start position:0% +poly exclusion principle. Right. So that + + + align:start position:0% +poly exclusion principle. Right. So that +electron has to have the opposite spin + + align:start position:0% +electron has to have the opposite spin + + + align:start position:0% +electron has to have the opposite spin +of this electron. + + align:start position:0% +of this electron. + + + align:start position:0% +of this electron. +And now we come to the 2p state. Okay. + + align:start position:0% +And now we come to the 2p state. Okay. + + + align:start position:0% +And now we come to the 2p state. Okay. +We put an electron in the 2p state here. + + align:start position:0% +We put an electron in the 2p state here. + + + align:start position:0% +We put an electron in the 2p state here. +So, we're at nitrogen. + + align:start position:0% +So, we're at nitrogen. + + + align:start position:0% +So, we're at nitrogen. +And it doesn't matter whether you put it + + align:start position:0% +And it doesn't matter whether you put it + + + align:start position:0% +And it doesn't matter whether you put it +in 2px, 2py, or 2pz because they have + + align:start position:0% +in 2px, 2py, or 2pz because they have + + + align:start position:0% +in 2px, 2py, or 2pz because they have +all the same energy, right? + + align:start position:0% +all the same energy, right? + + + align:start position:0% +all the same energy, right? +All right. But now we got to add another + + align:start position:0% +All right. But now we got to add another + + + align:start position:0% +All right. But now we got to add another +electron. We got to get to carbon. + + align:start position:0% +electron. We got to get to carbon. + + + align:start position:0% +electron. We got to get to carbon. +And when we get to carbon here, we're + + align:start position:0% +And when we get to carbon here, we're + + + align:start position:0% +And when we get to carbon here, we're +going to have to follow something else + + align:start position:0% +going to have to follow something else + + + align:start position:0% +going to have to follow something else +called the Hunts rule. And Hunts rule + + align:start position:0% +called the Hunts rule. And Hunts rule + + + align:start position:0% +called the Hunts rule. And Hunts rule +says the following. + + align:start position:0% +says the following. + + + align:start position:0% +says the following. +It says that when electrons are added to + + align:start position:0% +It says that when electrons are added to + + + align:start position:0% +It says that when electrons are added to +the states of the same energy, which is + + align:start position:0% +the states of the same energy, which is + + + align:start position:0% +the states of the same energy, which is +what we've got right here, right? + + align:start position:0% +what we've got right here, right? + + + align:start position:0% +what we've got right here, right? +A single electron enters each state + + align:start position:0% +A single electron enters each state + + + align:start position:0% +A single electron enters each state +before a second one enters any state. + + align:start position:0% +before a second one enters any state. + + + align:start position:0% +before a second one enters any state. +and the electrons the spins remain + + align:start position:0% +and the electrons the spins remain + + + align:start position:0% +and the electrons the spins remain +parallel. So where do we put carbon's + + align:start position:0% +parallel. So where do we put carbon's + + + align:start position:0% +parallel. So where do we put carbon's +electron? Do we put it here? + + align:start position:0% +electron? Do we put it here? + + + align:start position:0% +electron? Do we put it here? +Okay. No, because we violate something + + align:start position:0% +Okay. No, because we violate something + + + align:start position:0% +Okay. No, because we violate something +called Hunts rule. All right. So it + + align:start position:0% +called Hunts rule. All right. So it + + + align:start position:0% +called Hunts rule. All right. So it +means that we have to put it in 2py or + + align:start position:0% +means that we have to put it in 2py or + + + align:start position:0% +means that we have to put it in 2py or +2pz. + + align:start position:0% +2pz. + + + align:start position:0% +2pz. +But do we put it in here? No. It's + + align:start position:0% +But do we put it in here? No. It's + + + align:start position:0% +But do we put it in here? No. It's +upside down. According to Hunt's rule, + + align:start position:0% +upside down. According to Hunt's rule, + + + align:start position:0% +upside down. According to Hunt's rule, +the spins have to remain parallel. Could + + align:start position:0% +the spins have to remain parallel. Could + + + align:start position:0% +the spins have to remain parallel. Could +you turn up the volume a little bit? The + + align:start position:0% +you turn up the volume a little bit? The + + + align:start position:0% +you turn up the volume a little bit? The +spins have to remain uh parallel, right? + + align:start position:0% +spins have to remain uh parallel, right? + + + align:start position:0% +spins have to remain uh parallel, right? +In order to have the lowest energy + + align:start position:0% +In order to have the lowest energy + + + align:start position:0% +In order to have the lowest energy +configuration. + + align:start position:0% +configuration. + + + align:start position:0% +configuration. +All right. And so we've got to put it in + + align:start position:0% +All right. And so we've got to put it in + + + align:start position:0% +All right. And so we've got to put it in +here, right? And with the spin being + + align:start position:0% +here, right? And with the spin being + + + align:start position:0% +here, right? And with the spin being +parallel to the original to the spin of + + align:start position:0% +parallel to the original to the spin of + + + align:start position:0% +parallel to the original to the spin of +the other electron. + + align:start position:0% +the other electron. + + + align:start position:0% +the other electron. +Okay. So now we get to uh oxygen + + align:start position:0% +Okay. So now we get to uh oxygen + + + align:start position:0% +Okay. So now we get to uh oxygen +and uh we put the electron again in one + + align:start position:0% +and uh we put the electron again in one + + + align:start position:0% +and uh we put the electron again in one +of the other two p states. The spin has + + align:start position:0% +of the other two p states. The spin has + + + align:start position:0% +of the other two p states. The spin has +to be parallel. + + align:start position:0% +to be parallel. + + + align:start position:0% +to be parallel. +Okay. And then we keep going. Now we can + + align:start position:0% +Okay. And then we keep going. Now we can + + + align:start position:0% +Okay. And then we keep going. Now we can +start to double up on the two p states. + + align:start position:0% +start to double up on the two p states. + + + align:start position:0% +start to double up on the two p states. +All right. That electron goes in the + + align:start position:0% +All right. That electron goes in the + + + align:start position:0% +All right. That electron goes in the +other spin. That one goes the other + + align:start position:0% +other spin. That one goes the other + + + align:start position:0% +other spin. That one goes the other +spin. That one goes in the other spin. + + align:start position:0% +spin. That one goes in the other spin. + + + align:start position:0% +spin. That one goes in the other spin. +So now we're finished with the two p + + align:start position:0% +So now we're finished with the two p + + + align:start position:0% +So now we're finished with the two p +states. And now we're going to put the + + align:start position:0% +states. And now we're going to put the + + + align:start position:0% +states. And now we're going to put the +electron in 3s state and the next one. + + align:start position:0% +electron in 3s state and the next one. + + + align:start position:0% +electron in 3s state and the next one. +Now we're ready for the 3p states again. + + align:start position:0% +Now we're ready for the 3p states again. + + + align:start position:0% +Now we're ready for the 3p states again. +So the first one goes into one of the + + align:start position:0% +So the first one goes into one of the + + + align:start position:0% +So the first one goes into one of the +three p states. The second one goes into + + align:start position:0% +three p states. The second one goes into + + + align:start position:0% +three p states. The second one goes into +one of the other three p states and the + + align:start position:0% +one of the other three p states and the + + + align:start position:0% +one of the other three p states and the +spins remain parallel. + + align:start position:0% +spins remain parallel. + + + align:start position:0% +spins remain parallel. +And we keep going. + + align:start position:0% +And we keep going. + + + align:start position:0% +And we keep going. +So that's the alphab principle. That's + + align:start position:0% +So that's the alphab principle. That's + + + align:start position:0% +So that's the alphab principle. That's +how you write the electron + + align:start position:0% +how you write the electron + + + align:start position:0% +how you write the electron +configurations here then for all of the + + align:start position:0% +configurations here then for all of the + + + align:start position:0% +configurations here then for all of the +atoms in the periodic table. + + align:start position:0% +atoms in the periodic table. + + + align:start position:0% +atoms in the periodic table. +All right, heating those two uh rules. + + align:start position:0% + + + + align:start position:0% + +Okay, so uh let's take a look at this a + + align:start position:0% +Okay, so uh let's take a look at this a + + + align:start position:0% +Okay, so uh let's take a look at this a +little more in detail. + + align:start position:0% +little more in detail. + + + align:start position:0% +little more in detail. +We're going to start here just looking + + align:start position:0% +We're going to start here just looking + + + align:start position:0% +We're going to start here just looking +at the third period + + align:start position:0% +at the third period + + + align:start position:0% +at the third period +or the third row in the periodic table. + + align:start position:0% +or the third row in the periodic table. + + + align:start position:0% +or the third row in the periodic table. +So, we're starting here with sodium + + align:start position:0% +So, we're starting here with sodium + + + align:start position:0% +So, we're starting here with sodium +and going across. + + align:start position:0% + + + + align:start position:0% + +And here is the um here is the electron + + align:start position:0% +And here is the um here is the electron + + + align:start position:0% +And here is the um here is the electron +configuration. + + align:start position:0% + + + + align:start position:0% + +Okay, here's the electron configuration + + align:start position:0% +Okay, here's the electron configuration + + + align:start position:0% +Okay, here's the electron configuration +of sodium. + + align:start position:0% +of sodium. + + + align:start position:0% +of sodium. +And you see I put two electrons in 2 px, + + align:start position:0% +And you see I put two electrons in 2 px, + + + align:start position:0% +And you see I put two electrons in 2 px, +two and 2p y, two and 2pz. + + align:start position:0% +two and 2p y, two and 2pz. + + + align:start position:0% +two and 2p y, two and 2pz. +Well, if I'm just writing it like this, + + align:start position:0% +Well, if I'm just writing it like this, + + + align:start position:0% +Well, if I'm just writing it like this, +I don't mind that you just write them as + + align:start position:0% +I don't mind that you just write them as + + + align:start position:0% +I don't mind that you just write them as +2p6, + + align:start position:0% +2p6, + + + align:start position:0% +2p6, +okay? Because you can't really tell the + + align:start position:0% +okay? Because you can't really tell the + + + align:start position:0% +okay? Because you can't really tell the +difference here anyway, right? So, you + + align:start position:0% +difference here anyway, right? So, you + + + align:start position:0% +difference here anyway, right? So, you +could just write it as 2p6. + + align:start position:0% +could just write it as 2p6. + + + align:start position:0% +could just write it as 2p6. +Now, just a few reminders of things that + + align:start position:0% +Now, just a few reminders of things that + + + align:start position:0% +Now, just a few reminders of things that +you probably already know and that is + + align:start position:0% +you probably already know and that is + + + align:start position:0% +you probably already know and that is +that these electrons 1 s 2s and the 2p6, + + align:start position:0% +that these electrons 1 s 2s and the 2p6, + + + align:start position:0% +that these electrons 1 s 2s and the 2p6, +they're are core electrons. They make up + + align:start position:0% +they're are core electrons. They make up + + + align:start position:0% +they're are core electrons. They make up +the inner gas configuration. So + + align:start position:0% +the inner gas configuration. So + + + align:start position:0% +the inner gas configuration. So +electrons that make up an inner gas + + align:start position:0% +electrons that make up an inner gas + + + align:start position:0% +electrons that make up an inner gas +configuration we call our core + + align:start position:0% +configuration we call our core + + + align:start position:0% +configuration we call our core +electrons. + + align:start position:0% +electrons. + + + align:start position:0% +electrons. +And this inner gas configuration is that + + align:start position:0% +And this inner gas configuration is that + + + align:start position:0% +And this inner gas configuration is that +of neon. + + align:start position:0% +of neon. + + + align:start position:0% +of neon. +And so actually if you were to write the + + align:start position:0% +And so actually if you were to write the + + + align:start position:0% +And so actually if you were to write the +sodium electron configuration, it's fine + + align:start position:0% +sodium electron configuration, it's fine + + + align:start position:0% +sodium electron configuration, it's fine +to just write it as neon + + align:start position:0% +to just write it as neon + + + align:start position:0% +to just write it as neon +and then with the 3s1 next to it. The + + align:start position:0% +and then with the 3s1 next to it. The + + + align:start position:0% +and then with the 3s1 next to it. The +3s1 of course is the veence electron. + + align:start position:0% +3s1 of course is the veence electron. + + + align:start position:0% +3s1 of course is the veence electron. +Veence electrons are those electrons + + align:start position:0% +Veence electrons are those electrons + + + align:start position:0% +Veence electrons are those electrons +that are beyond the uh closest electron + + align:start position:0% +that are beyond the uh closest electron + + + align:start position:0% +that are beyond the uh closest electron +gas configuration. + + align:start position:0% +gas configuration. + + + align:start position:0% +gas configuration. +All right. + + align:start position:0% +All right. + + + align:start position:0% +All right. +Okay. So if we went across here this uh + + align:start position:0% +Okay. So if we went across here this uh + + + align:start position:0% +Okay. So if we went across here this uh +third row we would just fill up then the + + align:start position:0% +third row we would just fill up then the + + + align:start position:0% +third row we would just fill up then the +three p states and then we get to the + + align:start position:0% +three p states and then we get to the + + + align:start position:0% +three p states and then we get to the +configuration the inner gas + + align:start position:0% +configuration the inner gas + + + align:start position:0% +configuration the inner gas +configuration here of argon. + + align:start position:0% +configuration here of argon. + + + align:start position:0% +configuration here of argon. +Okay, let's look at the uh fourth period + + align:start position:0% +Okay, let's look at the uh fourth period + + + align:start position:0% +Okay, let's look at the uh fourth period +here starting with potassium and going + + align:start position:0% +here starting with potassium and going + + + align:start position:0% +here starting with potassium and going +across. + + align:start position:0% + + + + align:start position:0% + +All right, for potassium + + align:start position:0% +All right, for potassium + + + align:start position:0% +All right, for potassium +the electron configuration is that of + + align:start position:0% +the electron configuration is that of + + + align:start position:0% +the electron configuration is that of +argon + + align:start position:0% +argon + + + align:start position:0% +argon +plus one electron. And now what I want + + align:start position:0% +plus one electron. And now what I want + + + align:start position:0% +plus one electron. And now what I want +you to notice is that that extra + + align:start position:0% +you to notice is that that extra + + + align:start position:0% +you to notice is that that extra +electron went into this 4s state. it did + + align:start position:0% +electron went into this 4s state. it did + + + align:start position:0% +electron went into this 4s state. it did +not go into the 3d state. It turns out + + align:start position:0% +not go into the 3d state. It turns out + + + align:start position:0% +not go into the 3d state. It turns out +for potassium that the 4s state is + + align:start position:0% +for potassium that the 4s state is + + + align:start position:0% +for potassium that the 4s state is +actually lower in energy than the 3d + + align:start position:0% +actually lower in energy than the 3d + + + align:start position:0% +actually lower in energy than the 3d +state. + + align:start position:0% +state. + + + align:start position:0% +state. +Same thing here for calcium. The next + + align:start position:0% +Same thing here for calcium. The next + + + align:start position:0% +Same thing here for calcium. The next +electron, it goes into the 4s state. So + + align:start position:0% +electron, it goes into the 4s state. So + + + align:start position:0% +electron, it goes into the 4s state. So +the configuration is argon 4s2. It's not + + align:start position:0% +the configuration is argon 4s2. It's not + + + align:start position:0% +the configuration is argon 4s2. It's not +argon 3d2. + + align:start position:0% +argon 3d2. + + + align:start position:0% +argon 3d2. +4s is lower in energy than 3d. I'll show + + align:start position:0% +4s is lower in energy than 3d. I'll show + + + align:start position:0% +4s is lower in energy than 3d. I'll show +you a pneummonic pneummonic in a moment + + align:start position:0% +you a pneummonic pneummonic in a moment + + + align:start position:0% +you a pneummonic pneummonic in a moment +to try to remember that. + + align:start position:0% +to try to remember that. + + + align:start position:0% +to try to remember that. +Next, scandium another electron. Well, + + align:start position:0% +Next, scandium another electron. Well, + + + align:start position:0% +Next, scandium another electron. Well, +now the 3d states start filling up. + + align:start position:0% +now the 3d states start filling up. + + + align:start position:0% +now the 3d states start filling up. +Okay. 4s2 3d1. + + align:start position:0% +Okay. 4s2 3d1. + + + align:start position:0% +Okay. 4s2 3d1. +Titanium 4s2 3d2. Venadium 4s2 3d3. + + align:start position:0% +Titanium 4s2 3d2. Venadium 4s2 3d3. + + + align:start position:0% +Titanium 4s2 3d2. Venadium 4s2 3d3. +Chromium. We got a problem. All right. + + align:start position:0% +Chromium. We got a problem. All right. + + + align:start position:0% +Chromium. We got a problem. All right. +Chromium we got an exception here. You + + align:start position:0% +Chromium we got an exception here. You + + + align:start position:0% +Chromium we got an exception here. You +might expect it to be 4S23d4 + + align:start position:0% +might expect it to be 4S23d4 + + + align:start position:0% +might expect it to be 4S23d4 +because we're just filling up the + + align:start position:0% +because we're just filling up the + + + align:start position:0% +because we're just filling up the +dstates. It turns out that's not the + + align:start position:0% +dstates. It turns out that's not the + + + align:start position:0% +dstates. It turns out that's not the +case. + + align:start position:0% +case. + + + align:start position:0% +case. +It turns out that the chromium + + align:start position:0% +It turns out that the chromium + + + align:start position:0% +It turns out that the chromium +configuration is 4S13d5. + + align:start position:0% + + + + align:start position:0% + +How do you know this? You don't know + + align:start position:0% +How do you know this? You don't know + + + align:start position:0% +How do you know this? You don't know +this, right? There was no way to really + + align:start position:0% +this, right? There was no way to really + + + align:start position:0% +this, right? There was no way to really +predict this. This is an experimental + + align:start position:0% +predict this. This is an experimental + + + align:start position:0% +predict this. This is an experimental +observation. + + align:start position:0% +observation. + + + align:start position:0% +observation. +It turns out that having a half filled + + align:start position:0% +It turns out that having a half filled + + + align:start position:0% +It turns out that having a half filled +4s shell and a half filled 3d shell is + + align:start position:0% +4s shell and a half filled 3d shell is + + + align:start position:0% +4s shell and a half filled 3d shell is +more stable than having a filled 4s + + align:start position:0% +more stable than having a filled 4s + + + align:start position:0% +more stable than having a filled 4s +shell and four electrons in the 3d + + align:start position:0% +shell and four electrons in the 3d + + + align:start position:0% +shell and four electrons in the 3d +states. Okay, this is an exception. This + + align:start position:0% +states. Okay, this is an exception. This + + + align:start position:0% +states. Okay, this is an exception. This +is an exception you have to know. + + align:start position:0% +is an exception you have to know. + + + align:start position:0% +is an exception you have to know. +Okay. But now, yes, + + align:start position:0% + + + + align:start position:0% + +um I'm going to say that in a moment. It + + align:start position:0% +um I'm going to say that in a moment. It + + + align:start position:0% +um I'm going to say that in a moment. It +is an exception also for malibdum, + + align:start position:0% +is an exception also for malibdum, + + + align:start position:0% +is an exception also for malibdum, +right? And we'll talk about it. It is + + align:start position:0% +right? And we'll talk about it. It is + + + align:start position:0% +right? And we'll talk about it. It is +not the exception for tungsten or below. + + align:start position:0% +not the exception for tungsten or below. + + + align:start position:0% +not the exception for tungsten or below. +Okay. + + align:start position:0% + + + + align:start position:0% + +Okay. So as we continue to go across + + align:start position:0% +Okay. So as we continue to go across + + + align:start position:0% +Okay. So as we continue to go across +manganese now we're going back to our + + align:start position:0% +manganese now we're going back to our + + + align:start position:0% +manganese now we're going back to our +pattern + + align:start position:0% +pattern + + + align:start position:0% +pattern +4s2 3d5 + + align:start position:0% +4s2 3d5 + + + align:start position:0% +4s2 3d5 +iron 4s2 3d6 cobalt 4s2 3d7 nickel 4s2 + + align:start position:0% +iron 4s2 3d6 cobalt 4s2 3d7 nickel 4s2 + + + align:start position:0% +iron 4s2 3d6 cobalt 4s2 3d7 nickel 4s2 +3d8 and here we got another exception + + align:start position:0% +3d8 and here we got another exception + + + align:start position:0% +3d8 and here we got another exception +copper + + align:start position:0% +copper + + + align:start position:0% +copper +copper if you followed our pattern you + + align:start position:0% +copper if you followed our pattern you + + + align:start position:0% +copper if you followed our pattern you +might expect to be 4s23d9 + + align:start position:0% +might expect to be 4s23d9 + + + align:start position:0% +might expect to be 4s23d9 +it's not all All right, + + align:start position:0% +it's not all All right, + + + align:start position:0% +it's not all All right, +it is 4s1 3d10. + + align:start position:0% +it is 4s1 3d10. + + + align:start position:0% +it is 4s1 3d10. +Again, it turns out that the overall + + align:start position:0% +Again, it turns out that the overall + + + align:start position:0% +Again, it turns out that the overall +atom is more stable if that 4s state is + + align:start position:0% +atom is more stable if that 4s state is + + + align:start position:0% +atom is more stable if that 4s state is +half filled and the 3d state is totally + + align:start position:0% +half filled and the 3d state is totally + + + align:start position:0% +half filled and the 3d state is totally +filled. + + align:start position:0% +filled. + + + align:start position:0% +filled. +Did were would you be able to predict + + align:start position:0% +Did were would you be able to predict + + + align:start position:0% +Did were would you be able to predict +that? No, you're not going to be able to + + align:start position:0% +that? No, you're not going to be able to + + + align:start position:0% +that? No, you're not going to be able to +predict that. All right, this is an + + align:start position:0% +predict that. All right, this is an + + + align:start position:0% +predict that. All right, this is an +experimental observation + + align:start position:0% +experimental observation + + + align:start position:0% +experimental observation +and this is another exception that you + + align:start position:0% +and this is another exception that you + + + align:start position:0% +and this is another exception that you +do have to know. + + align:start position:0% +do have to know. + + + align:start position:0% +do have to know. +Okay, + + align:start position:0% +Okay, + + + align:start position:0% +Okay, +next zinc. Well, we're back to filling + + align:start position:0% +next zinc. Well, we're back to filling + + + align:start position:0% +next zinc. Well, we're back to filling +our pattern here or back to our pattern. + + align:start position:0% +our pattern here or back to our pattern. + + + align:start position:0% +our pattern here or back to our pattern. +This is 4s2 3d10. + + align:start position:0% +This is 4s2 3d10. + + + align:start position:0% +This is 4s2 3d10. +And then once the 3d10 states are filled + + align:start position:0% +And then once the 3d10 states are filled + + + align:start position:0% +And then once the 3d10 states are filled +or the 3d states are filled one that + + align:start position:0% +or the 3d states are filled one that + + + align:start position:0% +or the 3d states are filled one that +then we start filling the four p states + + align:start position:0% +then we start filling the four p states + + + align:start position:0% +then we start filling the four p states +as we go across here this fourth row and + + align:start position:0% +as we go across here this fourth row and + + + align:start position:0% +as we go across here this fourth row and +we get to the krypton inner gas + + align:start position:0% +we get to the krypton inner gas + + + align:start position:0% +we get to the krypton inner gas +configuration and these all follow a + + align:start position:0% +configuration and these all follow a + + + align:start position:0% +configuration and these all follow a +pattern just fill the four p states up. + + align:start position:0% + + + + align:start position:0% + +Okay. All right. So chromium and copper + + align:start position:0% +Okay. All right. So chromium and copper + + + align:start position:0% +Okay. All right. So chromium and copper +are two exceptions you have to know. + + align:start position:0% +are two exceptions you have to know. + + + align:start position:0% +are two exceptions you have to know. +Now + + align:start position:0% +Now + + + align:start position:0% +Now +what happens as we go across the fifth + + align:start position:0% +what happens as we go across the fifth + + + align:start position:0% +what happens as we go across the fifth +period here right here. So we're + + align:start position:0% +period here right here. So we're + + + align:start position:0% +period here right here. So we're +starting with rubidium. + + align:start position:0% +starting with rubidium. + + + align:start position:0% +starting with rubidium. +Well again the electron goes into the 5s + + align:start position:0% +Well again the electron goes into the 5s + + + align:start position:0% +Well again the electron goes into the 5s +state and not the 4d state. 5s is lower + + align:start position:0% +state and not the 4d state. 5s is lower + + + align:start position:0% +state and not the 4d state. 5s is lower +than the 4d. + + align:start position:0% +than the 4d. + + + align:start position:0% +than the 4d. +And for strontium, the electron goes + + align:start position:0% +And for strontium, the electron goes + + + align:start position:0% +And for strontium, the electron goes +into the 5s state, not the 4d state. So + + align:start position:0% +into the 5s state, not the 4d state. So + + + align:start position:0% +into the 5s state, not the 4d state. So +you fill up those 4s states or the 5s + + align:start position:0% +you fill up those 4s states or the 5s + + + align:start position:0% +you fill up those 4s states or the 5s +states before you start filling up the + + align:start position:0% +states before you start filling up the + + + align:start position:0% +states before you start filling up the +three 4d states here. All right? And + + align:start position:0% +three 4d states here. All right? And + + + align:start position:0% +three 4d states here. All right? And +just like copper and chromium are + + align:start position:0% +just like copper and chromium are + + + align:start position:0% +just like copper and chromium are +exceptions in filling the 3D states, + + align:start position:0% +exceptions in filling the 3D states, + + + align:start position:0% +exceptions in filling the 3D states, +malibdinum and silver are exceptions in + + align:start position:0% +malibdinum and silver are exceptions in + + + align:start position:0% +malibdinum and silver are exceptions in +filling the 4D states. All right. + + align:start position:0% +filling the 4D states. All right. + + + align:start position:0% +filling the 4D states. All right. +So these four exceptions, chromium, + + align:start position:0% +So these four exceptions, chromium, + + + align:start position:0% +So these four exceptions, chromium, +copper, malibdinum, and silver are + + align:start position:0% +copper, malibdinum, and silver are + + + align:start position:0% +copper, malibdinum, and silver are +exceptions that you do have to know. + + align:start position:0% +exceptions that you do have to know. + + + align:start position:0% +exceptions that you do have to know. +along this fifth period here. There are + + align:start position:0% +along this fifth period here. There are + + + align:start position:0% +along this fifth period here. There are +other exceptions. I don't expect you to + + align:start position:0% +other exceptions. I don't expect you to + + + align:start position:0% +other exceptions. I don't expect you to +know that. All right. But there are four + + align:start position:0% +know that. All right. But there are four + + + align:start position:0% +know that. All right. But there are four +exceptions that you do need to know. + + align:start position:0% +exceptions that you do need to know. + + + align:start position:0% +exceptions that you do need to know. +Yes. + + align:start position:0% + + + + align:start position:0% + +Okay, + + align:start position:0% +Okay, + + + align:start position:0% +Okay, +right. I actually don't care which way + + align:start position:0% +right. I actually don't care which way + + + align:start position:0% +right. I actually don't care which way +you write the electron configuration. + + align:start position:0% +you write the electron configuration. + + + align:start position:0% +you write the electron configuration. +Okay, I will care if I specifically ask + + align:start position:0% +Okay, I will care if I specifically ask + + + align:start position:0% +Okay, I will care if I specifically ask +you which state is lower in energy. + + align:start position:0% +you which state is lower in energy. + + + align:start position:0% +you which state is lower in energy. +Okay, but if you just write it, I + + align:start position:0% +Okay, but if you just write it, I + + + align:start position:0% +Okay, but if you just write it, I +actually don't care how you write it. + + align:start position:0% +actually don't care how you write it. + + + align:start position:0% +actually don't care how you write it. +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +All right. So now, how do you remember + + align:start position:0% +All right. So now, how do you remember + + + align:start position:0% +All right. So now, how do you remember +what the uh ordering is of these states? + + align:start position:0% +what the uh ordering is of these states? + + + align:start position:0% +what the uh ordering is of these states? +The energy ordering. Well, here's an uh + + align:start position:0% +The energy ordering. Well, here's an uh + + + align:start position:0% +The energy ordering. Well, here's an uh +pneummonic for you. Maybe you've seen + + align:start position:0% +pneummonic for you. Maybe you've seen + + + align:start position:0% +pneummonic for you. Maybe you've seen +this before. + + align:start position:0% +this before. + + + align:start position:0% +this before. +I'm going to start out writing 1 S like + + align:start position:0% +I'm going to start out writing 1 S like + + + align:start position:0% +I'm going to start out writing 1 S like +this. And then I'm going to write right + + align:start position:0% +this. And then I'm going to write right + + + align:start position:0% +this. And then I'm going to write right +underneath it 2 S. And then over one 2 P + + align:start position:0% +underneath it 2 S. And then over one 2 P + + + align:start position:0% +underneath it 2 S. And then over one 2 P +then 3 S 3 P 3d. + + align:start position:0% +then 3 S 3 P 3d. + + + align:start position:0% +then 3 S 3 P 3d. +Then 4S, 4 P, 4 D, 4 F. And then 5S, 5 + + align:start position:0% +Then 4S, 4 P, 4 D, 4 F. And then 5S, 5 + + + align:start position:0% +Then 4S, 4 P, 4 D, 4 F. And then 5S, 5 +P, 5D, 5D, 5F, 6S, 6P, 6D, 7S, 7P. And + + align:start position:0% +P, 5D, 5D, 5F, 6S, 6P, 6D, 7S, 7P. And + + + align:start position:0% +P, 5D, 5D, 5F, 6S, 6P, 6D, 7S, 7P. And +that's all that's going to be important + + align:start position:0% +that's all that's going to be important + + + align:start position:0% +that's all that's going to be important +right now. Okay. And now, how do I use + + align:start position:0% +right now. Okay. And now, how do I use + + + align:start position:0% +right now. Okay. And now, how do I use +this pattern to generate the energy + + align:start position:0% +this pattern to generate the energy + + + align:start position:0% +this pattern to generate the energy +orderings? Well, of course, 1s is + + align:start position:0% +orderings? Well, of course, 1s is + + + align:start position:0% +orderings? Well, of course, 1s is +lowest, + + align:start position:0% +lowest, + + + align:start position:0% +lowest, +but now I'm going to draw diagonals + + align:start position:0% +but now I'm going to draw diagonals + + + align:start position:0% +but now I'm going to draw diagonals +through this. So for example 1 S is + + align:start position:0% +through this. So for example 1 S is + + + align:start position:0% +through this. So for example 1 S is +lowest and then the next higher energy + + align:start position:0% +lowest and then the next higher energy + + + align:start position:0% +lowest and then the next higher energy +state is 2 P + + align:start position:0% +state is 2 P + + + align:start position:0% +state is 2 P +and then the next higher energy I 2S + + align:start position:0% +and then the next higher energy I 2S + + + align:start position:0% +and then the next higher energy I 2S +then the next higher energy state is 2 P + + align:start position:0% +then the next higher energy state is 2 P + + + align:start position:0% +then the next higher energy state is 2 P +and the state after that that's higher + + align:start position:0% +and the state after that that's higher + + + align:start position:0% +and the state after that that's higher +in energy is 3S + + align:start position:0% +in energy is 3S + + + align:start position:0% +in energy is 3S +and then I draw another diagonal so that + + align:start position:0% +and then I draw another diagonal so that + + + align:start position:0% +and then I draw another diagonal so that +the next higher energy state is 4 P and + + align:start position:0% +the next higher energy state is 4 P and + + + align:start position:0% +the next higher energy state is 4 P and +uh 3 P and 4S + + align:start position:0% +uh 3 P and 4S + + + align:start position:0% +uh 3 P and 4S +and draw another diagonal 3D D 4 P5S + + align:start position:0% +and draw another diagonal 3D D 4 P5S + + + align:start position:0% +and draw another diagonal 3D D 4 P5S +draw another diagonal 4 D 5P 6S another + + align:start position:0% +draw another diagonal 4 D 5P 6S another + + + align:start position:0% +draw another diagonal 4 D 5P 6S another +diagonal 4 F 5D6P7S + + align:start position:0% +diagonal 4 F 5D6P7S + + + align:start position:0% +diagonal 4 F 5D6P7S +and another diagonal. All right. So + + align:start position:0% +and another diagonal. All right. So + + + align:start position:0% +and another diagonal. All right. So +that's how you remember the relative + + align:start position:0% +that's how you remember the relative + + + align:start position:0% +that's how you remember the relative +energy ordering of these states. + + align:start position:0% +energy ordering of these states. + + + align:start position:0% +energy ordering of these states. +So you should be able to write the + + align:start position:0% +So you should be able to write the + + + align:start position:0% +So you should be able to write the +electron configuration of all atoms in + + align:start position:0% +electron configuration of all atoms in + + + align:start position:0% +electron configuration of all atoms in +the periodic table including the four + + align:start position:0% +the periodic table including the four + + + align:start position:0% +the periodic table including the four +exceptions. + + align:start position:0% +exceptions. + + + align:start position:0% +exceptions. +There are other exceptions but I won't + + align:start position:0% +There are other exceptions but I won't + + + align:start position:0% +There are other exceptions but I won't +expect you to write those. Okay. + + align:start position:0% +expect you to write those. Okay. + + + align:start position:0% +expect you to write those. Okay. +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +Now + + align:start position:0% +Now + + + align:start position:0% +Now +I have to tell you about something that + + align:start position:0% +I have to tell you about something that + + + align:start position:0% +I have to tell you about something that +is a little confusing + + align:start position:0% + + + + align:start position:0% + +and that is when we write down the + + align:start position:0% +and that is when we write down the + + + align:start position:0% +and that is when we write down the +electron configuration of ions. + + align:start position:0% +electron configuration of ions. + + + align:start position:0% +electron configuration of ions. +All right. + + align:start position:0% +All right. + + + align:start position:0% +All right. +What I'm about to say has nothing to do + + align:start position:0% +What I'm about to say has nothing to do + + + align:start position:0% +What I'm about to say has nothing to do +or doesn't change in any way what I just + + align:start position:0% +or doesn't change in any way what I just + + + align:start position:0% +or doesn't change in any way what I just +told you about writing the electron + + align:start position:0% +told you about writing the electron + + + align:start position:0% +told you about writing the electron +configuration of neutrals. + + align:start position:0% +configuration of neutrals. + + + align:start position:0% +configuration of neutrals. +But it does have something to do in + + align:start position:0% +But it does have something to do in + + + align:start position:0% +But it does have something to do in +writing the configuration of positive + + align:start position:0% +writing the configuration of positive + + + align:start position:0% +writing the configuration of positive +ions. + + align:start position:0% +ions. + + + align:start position:0% +ions. +And here's the story. + + align:start position:0% +And here's the story. + + + align:start position:0% +And here's the story. +If I actually look at the energies of + + align:start position:0% +If I actually look at the energies of + + + align:start position:0% +If I actually look at the energies of +the individual 4s states and 3d states + + align:start position:0% +the individual 4s states and 3d states + + + align:start position:0% +the individual 4s states and 3d states +as we go across the uh fourth row, + + align:start position:0% +as we go across the uh fourth row, + + + align:start position:0% +as we go across the uh fourth row, +potassium, calcium, scandium, titanium. + + align:start position:0% +potassium, calcium, scandium, titanium. + + + align:start position:0% +potassium, calcium, scandium, titanium. +Well, the 4s states in potassium and + + align:start position:0% +Well, the 4s states in potassium and + + + align:start position:0% +Well, the 4s states in potassium and +calcium are actually lower in energy + + align:start position:0% +calcium are actually lower in energy + + + align:start position:0% +calcium are actually lower in energy +than the 3d states. And indeed when we + + align:start position:0% +than the 3d states. And indeed when we + + + align:start position:0% +than the 3d states. And indeed when we +wrote the electron configuration of the + + align:start position:0% +wrote the electron configuration of the + + + align:start position:0% +wrote the electron configuration of the +neutral, we put that electron that extra + + align:start position:0% +neutral, we put that electron that extra + + + align:start position:0% +neutral, we put that electron that extra +electron making the potassium in the 4s + + align:start position:0% +electron making the potassium in the 4s + + + align:start position:0% +electron making the potassium in the 4s +state and that extra electron in this in + + align:start position:0% +state and that extra electron in this in + + + align:start position:0% +state and that extra electron in this in +the calcium making the + + align:start position:0% +the calcium making the + + + align:start position:0% +the calcium making the +uh a 4s state. Okay. But it turns out + + align:start position:0% +uh a 4s state. Okay. But it turns out + + + align:start position:0% +uh a 4s state. Okay. But it turns out +that right at this element scandium + + align:start position:0% +that right at this element scandium + + + align:start position:0% +that right at this element scandium +Z equ= 21 the energy of that 3d state + + align:start position:0% +Z equ= 21 the energy of that 3d state + + + align:start position:0% +Z equ= 21 the energy of that 3d state +drops below the energy of the 4s state. + + align:start position:0% +drops below the energy of the 4s state. + + + align:start position:0% +drops below the energy of the 4s state. +Does that have a consequence for how you + + align:start position:0% +Does that have a consequence for how you + + + align:start position:0% +Does that have a consequence for how you +write the electron condition + + align:start position:0% +write the electron condition + + + align:start position:0% +write the electron condition +configuration of scandium or titanium + + align:start position:0% +configuration of scandium or titanium + + + align:start position:0% +configuration of scandium or titanium +for example? No. + + align:start position:0% +for example? No. + + + align:start position:0% +for example? No. +The electron configuration for titanium + + align:start position:0% +The electron configuration for titanium + + + align:start position:0% +The electron configuration for titanium +is still what I said argon 4s2 3d2. + + align:start position:0% +is still what I said argon 4s2 3d2. + + + align:start position:0% +is still what I said argon 4s2 3d2. +All right. The fact that this 3d state + + align:start position:0% +All right. The fact that this 3d state + + + align:start position:0% +All right. The fact that this 3d state +is now lower in energy does not affect + + align:start position:0% +is now lower in energy does not affect + + + align:start position:0% +is now lower in energy does not affect +writing the electron configuration of + + align:start position:0% +writing the electron configuration of + + + align:start position:0% +writing the electron configuration of +the neutral. Now you might ask okay if + + align:start position:0% +the neutral. Now you might ask okay if + + + align:start position:0% +the neutral. Now you might ask okay if +the 3d states here at titanium are lower + + align:start position:0% +the 3d states here at titanium are lower + + + align:start position:0% +the 3d states here at titanium are lower +in energy why don't the 4s hop over into + + align:start position:0% +in energy why don't the 4s hop over into + + + align:start position:0% +in energy why don't the 4s hop over into +the 3d? They don't because this + + align:start position:0% +the 3d? They don't because this + + + align:start position:0% +the 3d? They don't because this +configuration again minimizes the + + align:start position:0% +configuration again minimizes the + + + align:start position:0% +configuration again minimizes the +electron repulsion. If you put all four + + align:start position:0% +electron repulsion. If you put all four + + + align:start position:0% +electron repulsion. If you put all four +electrons in the 3d state, there would + + align:start position:0% +electrons in the 3d state, there would + + + align:start position:0% +electrons in the 3d state, there would +be a greater electron repulsion. And + + align:start position:0% +be a greater electron repulsion. And + + + align:start position:0% +be a greater electron repulsion. And +then the overall energy, the overall + + align:start position:0% +then the overall energy, the overall + + + align:start position:0% +then the overall energy, the overall +energy + + align:start position:0% +energy + + + align:start position:0% +energy +would actually be higher. What I'm + + align:start position:0% +would actually be higher. What I'm + + + align:start position:0% +would actually be higher. What I'm +plotting here is just the energy of 3d + + align:start position:0% +plotting here is just the energy of 3d + + + align:start position:0% +plotting here is just the energy of 3d +and just the energy of 4s. + + align:start position:0% +and just the energy of 4s. + + + align:start position:0% +and just the energy of 4s. +But you what when you're looking at the + + align:start position:0% +But you what when you're looking at the + + + align:start position:0% +But you what when you're looking at the +electron configuration of an ion, you + + align:start position:0% +electron configuration of an ion, you + + + align:start position:0% +electron configuration of an ion, you +have to look at all the interactions and + + align:start position:0% +have to look at all the interactions and + + + align:start position:0% +have to look at all the interactions and +all of the energies. All right? So for + + align:start position:0% +all of the energies. All right? So for + + + align:start position:0% +all of the energies. All right? So for +the neutral, it's still what I said. + + align:start position:0% +the neutral, it's still what I said. + + + align:start position:0% +the neutral, it's still what I said. +However, now if I form an ion, if I take + + align:start position:0% +However, now if I form an ion, if I take + + + align:start position:0% +However, now if I form an ion, if I take +titanium and I make titanium 2+, hey, + + align:start position:0% +titanium and I make titanium 2+, hey, + + + align:start position:0% +titanium and I make titanium 2+, hey, +you know the electrons that come out, + + align:start position:0% +you know the electrons that come out, + + + align:start position:0% +you know the electrons that come out, +the electrons that come out are the + + align:start position:0% +the electrons that come out are the + + + align:start position:0% +the electrons that come out are the +electrons in the 4s state because + + align:start position:0% +electrons in the 4s state because + + + align:start position:0% +electrons in the 4s state because +they're the higher energy state. And so + + align:start position:0% +they're the higher energy state. And so + + + align:start position:0% +they're the higher energy state. And so +the electron configuration of titanium + + align:start position:0% +the electron configuration of titanium + + + align:start position:0% +the electron configuration of titanium +is the argon 3d^2. + + align:start position:0% +is the argon 3d^2. + + + align:start position:0% +is the argon 3d^2. +All right, that's important. And + + align:start position:0% +All right, that's important. And + + + align:start position:0% +All right, that's important. And +similarly for that fifth row + + align:start position:0% +similarly for that fifth row + + + align:start position:0% +similarly for that fifth row +right for rubidium strronium 5s is lower + + align:start position:0% +right for rubidium strronium 5s is lower + + + align:start position:0% +right for rubidium strronium 5s is lower +than 4d but right here at utbium 4d + + align:start position:0% +than 4d but right here at utbium 4d + + + align:start position:0% +than 4d but right here at utbium 4d +drops below 5s + + align:start position:0% +drops below 5s + + + align:start position:0% +drops below 5s +that does not affect the configuration + + align:start position:0% +that does not affect the configuration + + + align:start position:0% +that does not affect the configuration +that we wrote for the neutrals. So for + + align:start position:0% +that we wrote for the neutrals. So for + + + align:start position:0% +that we wrote for the neutrals. So for +example, here's silver. + + align:start position:0% +example, here's silver. + + + align:start position:0% +example, here's silver. +It's a 5S1 4d10. But if we make a silver + + align:start position:0% +It's a 5S1 4d10. But if we make a silver + + + align:start position:0% +It's a 5S1 4d10. But if we make a silver +ion, silver plus it's that 5s electron + + align:start position:0% +ion, silver plus it's that 5s electron + + + align:start position:0% +ion, silver plus it's that 5s electron +that leaves because it's the higher + + align:start position:0% +that leaves because it's the higher + + + align:start position:0% +that leaves because it's the higher +energy electron. And so the + + align:start position:0% +energy electron. And so the + + + align:start position:0% +energy electron. And so the +configuration is krypton 4d10. + + align:start position:0% +configuration is krypton 4d10. + + + align:start position:0% +configuration is krypton 4d10. +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +Okay. See you on Friday. \ No newline at end of file diff --git a/xeszYyi9ooM.txt b/xeszYyi9ooM.txt new file mode 100644 index 0000000000000000000000000000000000000000..cffeb3bcaf3f6605b3499c7856bbd961abe3ec5d --- /dev/null +++ b/xeszYyi9ooM.txt @@ -0,0 +1,93 @@ +Let us introduce +the error measures + +we used in building +the analytics models. + +We of course used R squared, +but we also used other measures. + +Next measure, the +so-called "penalty error," + +is motivated by the fact +that if you classify + +a very high-risk patient +as a low-risk patient, + +this is more costly +than the reverse, + +namely classifying +a low-risk patient + +as a very high-risk patient. + +Motivated by this, we +developed a penalty error. + +And the idea is to use +asymmetric penalties. + +The graph here-- +so it's a matrix-- + +where this is the outcome +and this is the forecast. + +For example, whenever we +classify a low-risk patient + +as high-risk, we +pay a penalty of 2, + +which is a difference of 3 minus +1, the difference in the error. + +But inversely, when you +classify a bracket 3 patient + +as bracket 1 patient, +this is double. + +The cost-- the penalty-- +is double the amount. + +So you observe that the off +diagonal penalties are double + +the corresponding penalties +in the lower diagonal. + +To judge the quality of the +analytics models we developed, + +we compare it with a baseline. + +And the baseline is +to simply predict + +that the cost in +the next "period" + +will be the cost in +the current period. + +We have observed that as far +as identification of brackets + +is concerned, the +accuracy was 75%. + +So namely, whenever we predict +that the risk is bracket 3-- + +indeed it is bracket 3-- +this happens 75% of the time, + +and the penalty error-- +the average penalty + +error of the +baseline-- was 0.56. \ No newline at end of file diff --git a/xsO2Ip6eiaY.txt b/xsO2Ip6eiaY.txt new file mode 100644 index 0000000000000000000000000000000000000000..41903fc30d7f39b3ae7ba0970676cc608c23f885 --- /dev/null +++ b/xsO2Ip6eiaY.txt @@ -0,0 +1,4363 @@ +align:start position:0% + +about seaplanes and + + align:start position:0% + + + + align:start position:0% + +two different designs you can have a + + align:start position:0% +two different designs you can have a + + + align:start position:0% +two different designs you can have a +boat whole seaplane or you can have a + + align:start position:0% +boat whole seaplane or you can have a + + + align:start position:0% +boat whole seaplane or you can have a +conventional airplane on floats so there + + align:start position:0% +conventional airplane on floats so there + + + align:start position:0% +conventional airplane on floats so there +at the bottom left is a part of the + + align:start position:0% +at the bottom left is a part of the + + + align:start position:0% +at the bottom left is a part of the +Grumman series they made a huge number + + align:start position:0% +Grumman series they made a huge number + + + align:start position:0% +Grumman series they made a huge number +of these around world war ii and many of + + align:start position:0% +of these around world war ii and many of + + + align:start position:0% +of these around world war ii and many of +them are still flying you can see always + + align:start position:0% +them are still flying you can see always + + + align:start position:0% +them are still flying you can see always +probably 15 or 20 of these at Oshkosh + + align:start position:0% +probably 15 or 20 of these at Oshkosh + + + align:start position:0% +probably 15 or 20 of these at Oshkosh +every year in different sizes the + + align:start position:0% +every year in different sizes the + + + align:start position:0% +every year in different sizes the +widgeon is the smallest the albatross is + + align:start position:0% +widgeon is the smallest the albatross is + + + align:start position:0% +widgeon is the smallest the albatross is +the biggest I forget if that's like a + + align:start position:0% +the biggest I forget if that's like a + + + align:start position:0% +the biggest I forget if that's like a +martin mars up there on the top left + + align:start position:0% +martin mars up there on the top left + + + align:start position:0% +martin mars up there on the top left +there were some huge truly huge sea + + align:start position:0% +there were some huge truly huge sea + + + align:start position:0% +there were some huge truly huge sea +planes boeing Sikorsky and martin I + + align:start position:0% +planes boeing Sikorsky and martin I + + + align:start position:0% +planes boeing Sikorsky and martin I +think all made huge sea planes during + + align:start position:0% +think all made huge sea planes during + + + align:start position:0% +think all made huge sea planes during +World War two and just before the bush + + align:start position:0% +World War two and just before the bush + + + align:start position:0% +World War two and just before the bush +pilots don't like the small boat hold + + align:start position:0% +pilots don't like the small boat hold + + + align:start position:0% +pilots don't like the small boat hold +sea planes like the lake amphibian and I + + align:start position:0% +sea planes like the lake amphibian and I + + + align:start position:0% +sea planes like the lake amphibian and I +guess the icon they probably wouldn't + + align:start position:0% +guess the icon they probably wouldn't + + + align:start position:0% +guess the icon they probably wouldn't +like if it ever did ship up there to + + align:start position:0% +like if it ever did ship up there to + + + align:start position:0% +like if it ever did ship up there to +Alaska I think one issue with the boat + + align:start position:0% +Alaska I think one issue with the boat + + + align:start position:0% +Alaska I think one issue with the boat +hull planes is they're very hard to dock + + align:start position:0% +hull planes is they're very hard to dock + + + align:start position:0% +hull planes is they're very hard to dock +you have to design some kind of special + + align:start position:0% +you have to design some kind of special + + + align:start position:0% +you have to design some kind of special +dock for them they really designed more + + align:start position:0% +dock for them they really designed more + + + align:start position:0% +dock for them they really designed more +for beaching whereas the float planes + + align:start position:0% +for beaching whereas the float planes + + + align:start position:0% +for beaching whereas the float planes +very naturally come up to a dock like a + + align:start position:0% +very naturally come up to a dock like a + + + align:start position:0% +very naturally come up to a dock like a +boat that's one issue so yeah you might + + align:start position:0% +boat that's one issue so yeah you might + + + align:start position:0% +boat that's one issue so yeah you might +think those float planes look so + + align:start position:0% +think those float planes look so + + + align:start position:0% +think those float planes look so +unstable but the bush pilots love them + + align:start position:0% +unstable but the bush pilots love them + + + align:start position:0% +unstable but the bush pilots love them +it's hard to get on and off the water + + align:start position:0% +it's hard to get on and off the water + + + align:start position:0% +it's hard to get on and off the water +which is why a practical sea plane + + align:start position:0% +which is why a practical sea plane + + + align:start position:0% +which is why a practical sea plane +really should have in most cases a + + align:start position:0% +really should have in most cases a + + + align:start position:0% +really should have in most cases a +turboprop engine to get enough power to + + align:start position:0% +turboprop engine to get enough power to + + + align:start position:0% +turboprop engine to get enough power to +really get off the water so we do have + + align:start position:0% +really get off the water so we do have + + + align:start position:0% +really get off the water so we do have +an Alaska locally it's called mean + + align:start position:0% +an Alaska locally it's called mean + + + align:start position:0% +an Alaska locally it's called mean +there's a fair amount of seaplane flying + + align:start position:0% +there's a fair amount of seaplane flying + + + align:start position:0% +there's a fair amount of seaplane flying +up there these are a couple US + + align:start position:0% +up there these are a couple US + + + align:start position:0% +up there these are a couple US +government planes if you want to know + + align:start position:0% +government planes if you want to know + + + align:start position:0% +government planes if you want to know +why your taxes are going in the + + align:start position:0% +why your taxes are going in the + + + align:start position:0% +why your taxes are going in the +direction that they're going look on the + + align:start position:0% +direction that they're going look on the + + + align:start position:0% +direction that they're going look on the +bottom right that was the government's I + + align:start position:0% +bottom right that was the government's I + + + align:start position:0% +bottom right that was the government's I +saw these two planes side-by-side on the + + align:start position:0% +saw these two planes side-by-side on the + + + align:start position:0% +saw these two planes side-by-side on the +ramp Portland Maine has a wonderful FBLA + + align:start position:0% +ramp Portland Maine has a wonderful FBLA + + + align:start position:0% +ramp Portland Maine has a wonderful FBLA +called Mack jets which is very + + align:start position:0% +called Mack jets which is very + + + align:start position:0% +called Mack jets which is very +hospitable they have crew cars + + align:start position:0% +hospitable they have crew cars + + + align:start position:0% +hospitable they have crew cars +reasonably priced hundred low-lead + + align:start position:0% +reasonably priced hundred low-lead + + + align:start position:0% +reasonably priced hundred low-lead +they're really just operating it as a + + align:start position:0% +they're really just operating it as a + + + align:start position:0% +they're really just operating it as a +gift to the piston crowd of course + + align:start position:0% +gift to the piston crowd of course + + + align:start position:0% +gift to the piston crowd of course +they're really there for the turbine as + + align:start position:0% +they're really there for the turbine as + + + align:start position:0% +they're really there for the turbine as +a business they're there for the jets + + align:start position:0% +a business they're there for the jets + + + align:start position:0% +a business they're there for the jets +but it's a great place that you can use + + align:start position:0% +but it's a great place that you can use + + + align:start position:0% +but it's a great place that you can use +and jump in the crew car going to town + + align:start position:0% +and jump in the crew car going to town + + + align:start position:0% +and jump in the crew car going to town +but anyway on the ramp I happen to see + + align:start position:0% +but anyway on the ramp I happen to see + + + align:start position:0% +but anyway on the ramp I happen to see +there's a little piston Cessna on floats + + align:start position:0% +there's a little piston Cessna on floats + + + align:start position:0% +there's a little piston Cessna on floats +that they bought + + align:start position:0% +that they bought + + + align:start position:0% +that they bought +fifteen or 20 years ago for Fish and + + align:start position:0% +fifteen or 20 years ago for Fish and + + + align:start position:0% +fifteen or 20 years ago for Fish and +Wildlife patrol or something I think + + align:start position:0% +Wildlife patrol or something I think + + + align:start position:0% +Wildlife patrol or something I think +this is a federal government airplane + + align:start position:0% +this is a federal government airplane + + + align:start position:0% +this is a federal government airplane +and now they have this monster thing + + align:start position:0% +and now they have this monster thing + + + align:start position:0% +and now they have this monster thing +that they were they're replacing it with + + align:start position:0% +that they were they're replacing it with + + + align:start position:0% +that they were they're replacing it with +it has a fire-breathing turboprop engine + + align:start position:0% +it has a fire-breathing turboprop engine + + + align:start position:0% +it has a fire-breathing turboprop engine +probably cost five times as much per + + align:start position:0% +probably cost five times as much per + + + align:start position:0% +probably cost five times as much per +hour to run okay every year in September + + align:start position:0% +hour to run okay every year in September + + + align:start position:0% +hour to run okay every year in September +there is the Moosehead Lake seaplane + + align:start position:0% +there is the Moosehead Lake seaplane + + + align:start position:0% +there is the Moosehead Lake seaplane +fly-in and you might ask can you fly in + + align:start position:0% +fly-in and you might ask can you fly in + + + align:start position:0% +fly-in and you might ask can you fly in +there and an East Coast + + align:start position:0% +there and an East Coast + + + align:start position:0% +there and an East Coast +Aero Club plane that you've rented the + + align:start position:0% +Aero Club plane that you've rented the + + + align:start position:0% +Aero Club plane that you've rented the +answer is yes although you probably + + align:start position:0% +answer is yes although you probably + + + align:start position:0% +answer is yes although you probably +can't fly back out if you choose the + + align:start position:0% +can't fly back out if you choose the + + + align:start position:0% +can't fly back out if you choose the +lake as your landing destination but + + align:start position:0% +lake as your landing destination but + + + align:start position:0% +lake as your landing destination but +there is a wheeled Airport there as well + + align:start position:0% +there is a wheeled Airport there as well + + + align:start position:0% +there is a wheeled Airport there as well +that's pretty reasonable I think it's + + align:start position:0% +that's pretty reasonable I think it's + + + align:start position:0% +that's pretty reasonable I think it's +about a 4,000 foot runway so if the + + align:start position:0% +about a 4,000 foot runway so if the + + + align:start position:0% +about a 4,000 foot runway so if the +weather is nice that's a great place to + + align:start position:0% +weather is nice that's a great place to + + + align:start position:0% +weather is nice that's a great place to +go up in Moosehead Lake it's a long + + align:start position:0% +go up in Moosehead Lake it's a long + + + align:start position:0% +go up in Moosehead Lake it's a long +drive it's about probably a five hour + + align:start position:0% +drive it's about probably a five hour + + + align:start position:0% +drive it's about probably a five hour +drive from here the hard thing about sea + + align:start position:0% +drive from here the hard thing about sea + + + align:start position:0% +drive from here the hard thing about sea +planes is if the float is all the way in + + align:start position:0% +planes is if the float is all the way in + + + align:start position:0% +planes is if the float is all the way in +the water it will never take off there's + + align:start position:0% +the water it will never take off there's + + + align:start position:0% +the water it will never take off there's +so much drag you have to get up on the + + align:start position:0% +so much drag you have to get up on the + + + align:start position:0% +so much drag you have to get up on the +step which if you're a boater + + align:start position:0% +step which if you're a boater + + + align:start position:0% +step which if you're a boater +corresponds to getting up on the plane I + + align:start position:0% +corresponds to getting up on the plane I + + + align:start position:0% +corresponds to getting up on the plane I +guess of a planing hull so basically you + + align:start position:0% +guess of a planing hull so basically you + + + align:start position:0% +guess of a planing hull so basically you +can't have the entire float in the water + + align:start position:0% +can't have the entire float in the water + + + align:start position:0% +can't have the entire float in the water +if you ever want to take off let's just + + align:start position:0% +if you ever want to take off let's just + + + align:start position:0% +if you ever want to take off let's just +show a short YouTube video here + + align:start position:0% + + + + align:start position:0% + +we have no sound oh well that's fine so + + align:start position:0% +we have no sound oh well that's fine so + + + align:start position:0% +we have no sound oh well that's fine so +you can see this caravan on floats I + + align:start position:0% +you can see this caravan on floats I + + + align:start position:0% +you can see this caravan on floats I +think it's a caravan it's beginning to + + align:start position:0% +think it's a caravan it's beginning to + + + align:start position:0% +think it's a caravan it's beginning to +get up on the step and finally it can + + align:start position:0% +get up on the step and finally it can + + + align:start position:0% +get up on the step and finally it can +break loose anyway that's how it's done + + align:start position:0% + + + + align:start position:0% + +crosswind landing this is how it's done + + align:start position:0% +crosswind landing this is how it's done + + + align:start position:0% +crosswind landing this is how it's done +according to the FAA + + align:start position:0% +according to the FAA + + + align:start position:0% +according to the FAA +so the FAA is mission the FAA is mission + + align:start position:0% +so the FAA is mission the FAA is mission + + + align:start position:0% +so the FAA is mission the FAA is mission +is in addition to regulating aviation + + align:start position:0% +is in addition to regulating aviation + + + align:start position:0% +is in addition to regulating aviation +they're explicitly supposed to promote + + align:start position:0% +they're explicitly supposed to promote + + + align:start position:0% +they're explicitly supposed to promote +aviation + + align:start position:0% +aviation + + + align:start position:0% +aviation +it's a rare agency so part of their + + align:start position:0% +it's a rare agency so part of their + + + align:start position:0% +it's a rare agency so part of their +mission is to encourage people to fly + + align:start position:0% +mission is to encourage people to fly + + + align:start position:0% +mission is to encourage people to fly +and this is the best that they can do + + align:start position:0% +and this is the best that they can do + + + align:start position:0% +and this is the best that they can do +for sea planes so it does tell you like + + align:start position:0% +for sea planes so it does tell you like + + + align:start position:0% +for sea planes so it does tell you like +I was telling you the problem with sea + + align:start position:0% +I was telling you the problem with sea + + + align:start position:0% +I was telling you the problem with sea +planes is you know if you make a if you + + align:start position:0% +planes is you know if you make a if you + + + align:start position:0% +planes is you know if you make a if you +make an error on Hanscom on runway 2 9 + + align:start position:0% +make an error on Hanscom on runway 2 9 + + + align:start position:0% +make an error on Hanscom on runway 2 9 +first of all it's 150 feet wide and the + + align:start position:0% +first of all it's 150 feet wide and the + + + align:start position:0% +first of all it's 150 feet wide and the +gear on your airplane might only be you + + align:start position:0% +gear on your airplane might only be you + + + align:start position:0% +gear on your airplane might only be you +know 10 feet wide so you can slide quite + + align:start position:0% +know 10 feet wide so you can slide quite + + + align:start position:0% +know 10 feet wide so you can slide quite +a bit left to right before you even + + align:start position:0% +a bit left to right before you even + + + align:start position:0% +a bit left to right before you even +leave the pavement if you do leave the + + align:start position:0% +leave the pavement if you do leave the + + + align:start position:0% +leave the pavement if you do leave the +pavement you're skipping along the grass + + align:start position:0% +pavement you're skipping along the grass + + + align:start position:0% +pavement you're skipping along the grass +and the owner is going to have some + + align:start position:0% +and the owner is going to have some + + + align:start position:0% +and the owner is going to have some +harsh words for you perhaps but + + align:start position:0% +harsh words for you perhaps but + + + align:start position:0% +harsh words for you perhaps but +otherwise nothing too dramatic is going + + align:start position:0% +otherwise nothing too dramatic is going + + + align:start position:0% +otherwise nothing too dramatic is going +to happen glass this is the FAA this is + + align:start position:0% +to happen glass this is the FAA this is + + + align:start position:0% +to happen glass this is the FAA this is +the FAA is glassy water landing + + align:start position:0% +the FAA is glassy water landing + + + align:start position:0% +the FAA is glassy water landing +demonstration so if there's no wind at + + align:start position:0% +demonstration so if there's no wind at + + + align:start position:0% +demonstration so if there's no wind at +all you might think that's great that's + + align:start position:0% +all you might think that's great that's + + + align:start position:0% +all you might think that's great that's +perfect for seaplane flying it's hard to + + align:start position:0% +perfect for seaplane flying it's hard to + + + align:start position:0% +perfect for seaplane flying it's hard to +judge where the water is a little bit of + + align:start position:0% +judge where the water is a little bit of + + + align:start position:0% +judge where the water is a little bit of +wind that causes some ripples on the + + align:start position:0% +wind that causes some ripples on the + + + align:start position:0% +wind that causes some ripples on the +water makes it much easier to judge your + + align:start position:0% +water makes it much easier to judge your + + + align:start position:0% +water makes it much easier to judge your +distance so here's your alternatives you + + align:start position:0% +distance so here's your alternatives you + + + align:start position:0% +distance so here's your alternatives you +can not flare it all and crash into the + + align:start position:0% +can not flare it all and crash into the + + + align:start position:0% +can not flare it all and crash into the +water that way or you can flare too high + + align:start position:0% +water that way or you can flare too high + + + align:start position:0% +water that way or you can flare too high +and then crash into the water + + align:start position:0% + + + + align:start position:0% + +what's that those are the only + + align:start position:0% +what's that those are the only + + + align:start position:0% +what's that those are the only +possibilities that's the question radar + + align:start position:0% +possibilities that's the question radar + + + align:start position:0% +possibilities that's the question radar +all radar altimeter + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +the question is do you wait until VR to + + align:start position:0% +the question is do you wait until VR to + + + align:start position:0% +the question is do you wait until VR to +take off or you just wait till the + + align:start position:0% +take off or you just wait till the + + + align:start position:0% +take off or you just wait till the +floats cleared the water and take off + + align:start position:0% +floats cleared the water and take off + + + align:start position:0% +floats cleared the water and take off +that's a good question + + align:start position:0% +that's a good question + + + align:start position:0% +that's a good question +it's so inefficient to be dragged into + + align:start position:0% +it's so inefficient to be dragged into + + + align:start position:0% +it's so inefficient to be dragged into +the water I think you lift out of the + + align:start position:0% +the water I think you lift out of the + + + align:start position:0% +the water I think you lift out of the +water just as soon as you can and then + + align:start position:0% +water just as soon as you can and then + + + align:start position:0% +water just as soon as you can and then +you'll probably you know float you'll + + align:start position:0% +you'll probably you know float you'll + + + align:start position:0% +you'll probably you know float you'll +fly along the ground effect for a little + + align:start position:0% +fly along the ground effect for a little + + + align:start position:0% +fly along the ground effect for a little +bit and then finally take off but yeah + + align:start position:0% +bit and then finally take off but yeah + + + align:start position:0% +bit and then finally take off but yeah +just like this just like on a soft field + + align:start position:0% +just like this just like on a soft field + + + align:start position:0% +just like this just like on a soft field +like you know slightly muddy grass or + + align:start position:0% +like you know slightly muddy grass or + + + align:start position:0% +like you know slightly muddy grass or +something the best thing you can do is + + align:start position:0% +something the best thing you can do is + + + align:start position:0% +something the best thing you can do is +to get away from the surface that's + + align:start position:0% +to get away from the surface that's + + + align:start position:0% +to get away from the surface that's +dragging dragging on you + + align:start position:0% +dragging dragging on you + + + align:start position:0% +dragging dragging on you +great question all right here's a + + align:start position:0% +great question all right here's a + + + align:start position:0% +great question all right here's a +docking and beaching so one challenge + + align:start position:0% +docking and beaching so one challenge + + + align:start position:0% +docking and beaching so one challenge +with the seaplane if you're all by + + align:start position:0% +with the seaplane if you're all by + + + align:start position:0% +with the seaplane if you're all by +yourself is you have to be tremendously + + align:start position:0% +yourself is you have to be tremendously + + + align:start position:0% +yourself is you have to be tremendously +agile and nimble to sort of get out of + + align:start position:0% +agile and nimble to sort of get out of + + + align:start position:0% +agile and nimble to sort of get out of +the plane kill the engine + + align:start position:0% +the plane kill the engine + + + align:start position:0% +the plane kill the engine +scramble around usually the front of the + + align:start position:0% +scramble around usually the front of the + + + align:start position:0% +scramble around usually the front of the +airplane and the propeller because + + align:start position:0% +airplane and the propeller because + + + align:start position:0% +airplane and the propeller because +you're sitting on the left and I don't + + align:start position:0% +you're sitting on the left and I don't + + + align:start position:0% +you're sitting on the left and I don't +know the passengers are gonna go off on + + align:start position:0% +know the passengers are gonna go off on + + + align:start position:0% +know the passengers are gonna go off on +the right and tie up the airplane to the + + align:start position:0% +the right and tie up the airplane to the + + + align:start position:0% +the right and tie up the airplane to the +dock it's very hard to do it's one of + + align:start position:0% +dock it's very hard to do it's one of + + + align:start position:0% +dock it's very hard to do it's one of +the hardest things I think about sea + + align:start position:0% +the hardest things I think about sea + + + align:start position:0% +the hardest things I think about sea +planes and also if the Magneto's aren't + + align:start position:0% +planes and also if the Magneto's aren't + + + align:start position:0% +planes and also if the Magneto's aren't +perfectly grounded airplane engines can + + align:start position:0% +perfectly grounded airplane engines can + + + align:start position:0% +perfectly grounded airplane engines can +start by themselves after saying you + + align:start position:0% +start by themselves after saying you + + + align:start position:0% +start by themselves after saying you +know we shouldn't tell you stuff that's + + align:start position:0% +know we shouldn't tell you stuff that's + + + align:start position:0% +know we shouldn't tell you stuff that's +scary you know if it's not perfectly + + align:start position:0% +scary you know if it's not perfectly + + + align:start position:0% +scary you know if it's not perfectly +grounded by that switch and you don't + + align:start position:0% +grounded by that switch and you don't + + + align:start position:0% +grounded by that switch and you don't +starve the engine of the fuel by killing + + align:start position:0% +starve the engine of the fuel by killing + + + align:start position:0% +starve the engine of the fuel by killing +it with the mixture it may be able to + + align:start position:0% +it with the mixture it may be able to + + + align:start position:0% +it with the mixture it may be able to +start all by itself at least run for you + + align:start position:0% +start all by itself at least run for you + + + align:start position:0% +start all by itself at least run for you +know half a rotation or full rotation + + align:start position:0% +know half a rotation or full rotation + + + align:start position:0% +know half a rotation or full rotation +and hurt somebody so you know you always + + align:start position:0% +and hurt somebody so you know you always + + + align:start position:0% +and hurt somebody so you know you always +want to be cautious around propellers + + align:start position:0% +want to be cautious around propellers + + + align:start position:0% +want to be cautious around propellers +and not spin them but of course if + + align:start position:0% +and not spin them but of course if + + + align:start position:0% +and not spin them but of course if +you're trying to get around the front - + + align:start position:0% +you're trying to get around the front - + + + align:start position:0% +you're trying to get around the front - +for your seaplane repellers the most + + align:start position:0% +for your seaplane repellers the most + + + align:start position:0% +for your seaplane repellers the most +obvious thing to grab on to anyway + + align:start position:0% +obvious thing to grab on to anyway + + + align:start position:0% +obvious thing to grab on to anyway +that's I don't think I would ever want + + align:start position:0% +that's I don't think I would ever want + + + align:start position:0% +that's I don't think I would ever want +to fly a seaplane unless there were dock + + align:start position:0% +to fly a seaplane unless there were dock + + + align:start position:0% +to fly a seaplane unless there were dock +handlers who were gonna deal with the + + align:start position:0% +handlers who were gonna deal with the + + + align:start position:0% +handlers who were gonna deal with the +that part of you know welcoming the + + align:start position:0% +that part of you know welcoming the + + + align:start position:0% +that part of you know welcoming the +airplane to the dock and tying it all + + align:start position:0% +airplane to the dock and tying it all + + + align:start position:0% +airplane to the dock and tying it all +out but of course the folks in Alaska + + align:start position:0% +out but of course the folks in Alaska + + + align:start position:0% +out but of course the folks in Alaska +they do this all the time + + align:start position:0% +they do this all the time + + + align:start position:0% +they do this all the time +so I have have respect when you see a + + align:start position:0% +so I have have respect when you see a + + + align:start position:0% +so I have have respect when you see a +seaplane so there are a lot of bad + + align:start position:0% +seaplane so there are a lot of bad + + + align:start position:0% +seaplane so there are a lot of bad +things that you can do believe it or not + + align:start position:0% +things that you can do believe it or not + + + align:start position:0% +things that you can do believe it or not +landing in the sea is something that's + + align:start position:0% +landing in the sea is something that's + + + align:start position:0% +landing in the sea is something that's +almost impractical it's almost + + align:start position:0% +almost impractical it's almost + + + align:start position:0% +almost impractical it's almost +impossible on a seaplane because there's + + align:start position:0% +impossible on a seaplane because there's + + + align:start position:0% +impossible on a seaplane because there's +too much in the way of waves they're + + align:start position:0% +too much in the way of waves they're + + + align:start position:0% +too much in the way of waves they're +really for harbors rivers lakes if you + + align:start position:0% +really for harbors rivers lakes if you + + + align:start position:0% +really for harbors rivers lakes if you +have more than a foot of so if the waves + + align:start position:0% +have more than a foot of so if the waves + + + align:start position:0% +have more than a foot of so if the waves +are more than about a foot it just hangs + + align:start position:0% +are more than about a foot it just hangs + + + align:start position:0% +are more than about a foot it just hangs +up the sea plane so much that it'll be + + align:start position:0% +up the sea plane so much that it'll be + + + align:start position:0% +up the sea plane so much that it'll be +damaged landing the amphibious playing + + align:start position:0% +damaged landing the amphibious playing + + + align:start position:0% +damaged landing the amphibious playing +with the wheels down is one of the most + + align:start position:0% +with the wheels down is one of the most + + + align:start position:0% +with the wheels down is one of the most +common mistakes you might think software + + align:start position:0% +common mistakes you might think software + + + align:start position:0% +common mistakes you might think software +would fix this and you know you have a + + align:start position:0% +would fix this and you know you have a + + + align:start position:0% +would fix this and you know you have a +database of where all the runways are in + + align:start position:0% +database of where all the runways are in + + + align:start position:0% +database of where all the runways are in +the US you have a database of you know + + align:start position:0% +the US you have a database of you know + + + align:start position:0% +the US you have a database of you know +where the lakes are and other bodies of + + align:start position:0% +where the lakes are and other bodies of + + + align:start position:0% +where the lakes are and other bodies of +water but you don't even really need + + align:start position:0% +water but you don't even really need + + + align:start position:0% +water but you don't even really need +that so you could have a lot and you + + align:start position:0% +that so you could have a lot and you + + + align:start position:0% +that so you could have a lot and you +have it you could have a camera out at + + align:start position:0% +have it you could have a camera out at + + + align:start position:0% +have it you could have a camera out at +the front that can tell the difference + + align:start position:0% +the front that can tell the difference + + + align:start position:0% +the front that can tell the difference +between water and not water so you would + + align:start position:0% +between water and not water so you would + + + align:start position:0% +between water and not water so you would +think that the airplane would provide + + align:start position:0% +think that the airplane would provide + + + align:start position:0% +think that the airplane would provide +significant assistance in configuring an + + align:start position:0% +significant assistance in configuring an + + + align:start position:0% +significant assistance in configuring an +amphibious plane without either wheels + + align:start position:0% +amphibious plane without either wheels + + + align:start position:0% +amphibious plane without either wheels +down for a hard surface or the floats or + + align:start position:0% +down for a hard surface or the floats or + + + align:start position:0% +down for a hard surface or the floats or +just the bare floats for water and + + align:start position:0% +just the bare floats for water and + + + align:start position:0% +just the bare floats for water and +there's there's very little of that + + align:start position:0% +there's there's very little of that + + + align:start position:0% +there's there's very little of that +unfortunately there's certainly nothing + + align:start position:0% +unfortunately there's certainly nothing + + + align:start position:0% +unfortunately there's certainly nothing +like the intelligence that I'm + + align:start position:0% +like the intelligence that I'm + + + align:start position:0% +like the intelligence that I'm +describing you know you might be able to + + align:start position:0% +describing you know you might be able to + + + align:start position:0% +describing you know you might be able to +like press a button and have that plane + + align:start position:0% +like press a button and have that plane + + + align:start position:0% +like press a button and have that plane +tell you or the synthesized voice is an + + align:start position:0% +tell you or the synthesized voice is an + + + align:start position:0% +tell you or the synthesized voice is an +aftermarket thing you know the wheels + + align:start position:0% +aftermarket thing you know the wheels + + + align:start position:0% +aftermarket thing you know the wheels +are down for runway landing or something + + align:start position:0% +are down for runway landing or something + + + align:start position:0% +are down for runway landing or something +so one common thing that people forget + + align:start position:0% +so one common thing that people forget + + + align:start position:0% +so one common thing that people forget +and not that common but this is an + + align:start position:0% +and not that common but this is an + + + align:start position:0% +and not that common but this is an +illustration of why you might want a to + + align:start position:0% +illustration of why you might want a to + + + align:start position:0% +illustration of why you might want a to +pilot crew but there's a video that's + + align:start position:0% +pilot crew but there's a video that's + + + align:start position:0% +pilot crew but there's a video that's +linked here from the slide about a + + align:start position:0% +linked here from the slide about a + + + align:start position:0% +linked here from the slide about a +father it sounds like a good pilot in a + + align:start position:0% +father it sounds like a good pilot in a + + + align:start position:0% +father it sounds like a good pilot in a +careful pilot he is with the son and he + + align:start position:0% +careful pilot he is with the son and he + + + align:start position:0% +careful pilot he is with the son and he +left the wheels down landed in the water + + align:start position:0% +left the wheels down landed in the water + + + align:start position:0% +left the wheels down landed in the water +flipped over and the son was killed + + align:start position:0% +flipped over and the son was killed + + + align:start position:0% +flipped over and the son was killed +really tragic so watch that if you want + + align:start position:0% +really tragic so watch that if you want + + + align:start position:0% +really tragic so watch that if you want +to cry but anyway I think it's a good + + align:start position:0% +to cry but anyway I think it's a good + + + align:start position:0% +to cry but anyway I think it's a good +illustration of you know seaplane out + + align:start position:0% +illustration of you know seaplane out + + + align:start position:0% +illustration of you know seaplane out +amphibious sea print operation is a + + align:start position:0% +amphibious sea print operation is a + + + align:start position:0% +amphibious sea print operation is a +great example of where two pilot crew + + align:start position:0% +great example of where two pilot crew + + + align:start position:0% +great example of where two pilot crew +with the checklist would be very + + align:start position:0% +with the checklist would be very + + + align:start position:0% +with the checklist would be very +unlikely to have that kind of accident + + align:start position:0% +unlikely to have that kind of accident + + + align:start position:0% +unlikely to have that kind of accident +so it also illustrates you know how it's + + align:start position:0% +so it also illustrates you know how it's + + + align:start position:0% +so it also illustrates you know how it's +too bad that these manned airplanes + + align:start position:0% +too bad that these manned airplanes + + + align:start position:0% +too bad that these manned airplanes +don't have 1/100 of the intelligence of + + align:start position:0% +don't have 1/100 of the intelligence of + + + align:start position:0% +don't have 1/100 of the intelligence of +a DJI drone they're rare exceptions like + + align:start position:0% +a DJI drone they're rare exceptions like + + + align:start position:0% +a DJI drone they're rare exceptions like +I said at Burning Man + + align:start position:0% +I said at Burning Man + + + align:start position:0% +I said at Burning Man +you know the terrain warning system had + + align:start position:0% +you know the terrain warning system had + + + align:start position:0% +you know the terrain warning system had +to be silenced because it was freaking + + align:start position:0% +to be silenced because it was freaking + + + align:start position:0% +to be silenced because it was freaking +out that we were not going to make it + + align:start position:0% +out that we were not going to make it + + + align:start position:0% +out that we were not going to make it +even though there was a 5,000 foot + + align:start position:0% +even though there was a 5,000 foot + + + align:start position:0% +even though there was a 5,000 foot +temporary runway that had been rolled + + align:start position:0% +temporary runway that had been rolled + + + align:start position:0% +temporary runway that had been rolled +out there by the burners the uber + + align:start position:0% +out there by the burners the uber + + + align:start position:0% +out there by the burners the uber +burners okay salt waters you know people + + align:start position:0% +burners okay salt waters you know people + + + align:start position:0% +burners okay salt waters you know people +do this commercially but you know the + + align:start position:0% +do this commercially but you know the + + + align:start position:0% +do this commercially but you know the +airplane has to be hosed off every day + + align:start position:0% +airplane has to be hosed off every day + + + align:start position:0% +airplane has to be hosed off every day +because the salt water is corrosive even + + align:start position:0% +because the salt water is corrosive even + + + align:start position:0% +because the salt water is corrosive even +to aluminum question swimmers and + + align:start position:0% +to aluminum question swimmers and + + + align:start position:0% +to aluminum question swimmers and +boaters in lakes and harbors yeah that's + + align:start position:0% +boaters in lakes and harbors yeah that's + + + align:start position:0% +boaters in lakes and harbors yeah that's +one of the challenges of sea planes you + + align:start position:0% +one of the challenges of sea planes you + + + align:start position:0% +one of the challenges of sea planes you +know if you're cleared land in an + + align:start position:0% +know if you're cleared land in an + + + align:start position:0% +know if you're cleared land in an +airport the air traffic controller has + + align:start position:0% +airport the air traffic controller has + + + align:start position:0% +airport the air traffic controller has +looked out of the runway you know made + + align:start position:0% +looked out of the runway you know made + + + align:start position:0% +looked out of the runway you know made +sure that there's no other aircraft + + align:start position:0% +sure that there's no other aircraft + + + align:start position:0% +sure that there's no other aircraft +pretty sure that there's no deer on the + + align:start position:0% +pretty sure that there's no deer on the + + + align:start position:0% +pretty sure that there's no deer on the +runway the you know the sea plane you + + align:start position:0% +runway the you know the sea plane you + + + align:start position:0% +runway the you know the sea plane you +have to kind of orbit around it's a + + align:start position:0% +have to kind of orbit around it's a + + + align:start position:0% +have to kind of orbit around it's a +little bit like landing a helicopter off + + align:start position:0% +little bit like landing a helicopter off + + + align:start position:0% +little bit like landing a helicopter off +Airport to really make sure that there's + + align:start position:0% +Airport to really make sure that there's + + + align:start position:0% +Airport to really make sure that there's +nobody in a canoe I will tell you that + + align:start position:0% +nobody in a canoe I will tell you that + + + align:start position:0% +nobody in a canoe I will tell you that +for my seaplane training up in me and I + + align:start position:0% +for my seaplane training up in me and I + + + align:start position:0% +for my seaplane training up in me and I +have a seaplane rating that I got up in + + align:start position:0% +have a seaplane rating that I got up in + + + align:start position:0% +have a seaplane rating that I got up in +Maine and there's a great school up + + align:start position:0% +Maine and there's a great school up + + + align:start position:0% +Maine and there's a great school up +there called Twitchell's + + align:start position:0% +there called Twitchell's + + + align:start position:0% +there called Twitchell's +but anyway yeah if you see like kayakers + + align:start position:0% +but anyway yeah if you see like kayakers + + + align:start position:0% +but anyway yeah if you see like kayakers +they can pal pretty fast when they see + + align:start position:0% +they can pal pretty fast when they see + + + align:start position:0% +they can pal pretty fast when they see +is he playing in the vicinity but yeah + + align:start position:0% +is he playing in the vicinity but yeah + + + align:start position:0% +is he playing in the vicinity but yeah +there could be a log in the water so + + align:start position:0% +there could be a log in the water so + + + align:start position:0% +there could be a log in the water so +there's just their hazards that you + + align:start position:0% +there's just their hazards that you + + + align:start position:0% +there's just their hazards that you +can't you can't control and get rid of + + align:start position:0% +can't you can't control and get rid of + + + align:start position:0% +can't you can't control and get rid of +so the accident rate does tend to be + + align:start position:0% +so the accident rate does tend to be + + + align:start position:0% +so the accident rate does tend to be +higher in the military I think there's a + + align:start position:0% +higher in the military I think there's a + + + align:start position:0% +higher in the military I think there's a +slide later where we talk about that + + align:start position:0% +slide later where we talk about that + + + align:start position:0% +slide later where we talk about that +they've gotten away from sea planes and + + align:start position:0% +they've gotten away from sea planes and + + + align:start position:0% +they've gotten away from sea planes and +into helicopters for that reason you + + align:start position:0% +into helicopters for that reason you + + + align:start position:0% +into helicopters for that reason you +know the helicopter you can be down to + + align:start position:0% +know the helicopter you can be down to + + + align:start position:0% +know the helicopter you can be down to +within two feet of the ground and say + + align:start position:0% +within two feet of the ground and say + + + align:start position:0% +within two feet of the ground and say +you know I don't like what I see I'm + + align:start position:0% +you know I don't like what I see I'm + + + align:start position:0% +you know I don't like what I see I'm +gonna go somewhere else the propeller + + align:start position:0% +gonna go somewhere else the propeller + + + align:start position:0% +gonna go somewhere else the propeller +tends to get beaten up you'll see some + + align:start position:0% +tends to get beaten up you'll see some + + + align:start position:0% +tends to get beaten up you'll see some +seaplane designs or the propellers you + + align:start position:0% +seaplane designs or the propellers you + + + align:start position:0% +seaplane designs or the propellers you +know up high and in the back and that's + + align:start position:0% +know up high and in the back and that's + + + align:start position:0% +know up high and in the back and that's +to keep the water you know propellers + + align:start position:0% +to keep the water you know propellers + + + align:start position:0% +to keep the water you know propellers +going you're supersonic speeds at the + + align:start position:0% +going you're supersonic speeds at the + + + align:start position:0% +going you're supersonic speeds at the +tips + + align:start position:0% +tips + + + align:start position:0% +tips +so if it gets water on it it'll it'll be + + align:start position:0% +so if it gets water on it it'll it'll be + + + align:start position:0% +so if it gets water on it it'll it'll be +eroded same deal with flying your + + align:start position:0% +eroded same deal with flying your + + + align:start position:0% +eroded same deal with flying your +airplane and heavy rain you can get + + align:start position:0% +airplane and heavy rain you can get + + + align:start position:0% +airplane and heavy rain you can get +erosion on the leading edges of the wing + + align:start position:0% +erosion on the leading edges of the wing + + + align:start position:0% +erosion on the leading edges of the wing +and on the prop alright so yeah the + + align:start position:0% +and on the prop alright so yeah the + + + align:start position:0% +and on the prop alright so yeah the +seaplane pilot skills include a lot more + + align:start position:0% +seaplane pilot skills include a lot more + + + align:start position:0% +seaplane pilot skills include a lot more +judgment there's some extent there'll be + + align:start position:0% +judgment there's some extent there'll be + + + align:start position:0% +judgment there's some extent there'll be +the dimensions of these lakes and you + + align:start position:0% +the dimensions of these lakes and you + + + align:start position:0% +the dimensions of these lakes and you +know even in Alaska there's even a + + align:start position:0% +know even in Alaska there's even a + + + align:start position:0% +know even in Alaska there's even a +lighted water runway but generally + + align:start position:0% +lighted water runway but generally + + + align:start position:0% +lighted water runway but generally +speaking you don't have a lot of + + align:start position:0% +speaking you don't have a lot of + + + align:start position:0% +speaking you don't have a lot of +information to go by so you've got to + + align:start position:0% +information to go by so you've got to + + + align:start position:0% +information to go by so you've got to +evaluate all the stuff by yourself one + + align:start position:0% +evaluate all the stuff by yourself one + + + align:start position:0% +evaluate all the stuff by yourself one +thing you can do I'll use this coffee + + align:start position:0% +thing you can do I'll use this coffee + + + align:start position:0% +thing you can do I'll use this coffee +cup is an example you can usually see + + align:start position:0% +cup is an example you can usually see + + + align:start position:0% +cup is an example you can usually see +where the winds coming from if there's + + align:start position:0% +where the winds coming from if there's + + + align:start position:0% +where the winds coming from if there's +trees all around the lake the lake will + + align:start position:0% +trees all around the lake the lake will + + + align:start position:0% +trees all around the lake the lake will +be calm right next let's assume this + + align:start position:0% +be calm right next let's assume this + + + align:start position:0% +be calm right next let's assume this +coffee cup is a tree the lake will be + + align:start position:0% +coffee cup is a tree the lake will be + + + align:start position:0% +coffee cup is a tree the lake will be +calm and glassy right next to the tree + + align:start position:0% +calm and glassy right next to the tree + + + align:start position:0% +calm and glassy right next to the tree +and that tells you the wind is coming + + align:start position:0% +and that tells you the wind is coming + + + align:start position:0% +and that tells you the wind is coming +from this direction because that part of + + align:start position:0% +from this direction because that part of + + + align:start position:0% +from this direction because that part of +the lake is being sheltered from the + + align:start position:0% +the lake is being sheltered from the + + + align:start position:0% +the lake is being sheltered from the +wind + + align:start position:0% +wind + + + align:start position:0% +wind +so you can't actually read the wind off + + align:start position:0% +so you can't actually read the wind off + + + align:start position:0% +so you can't actually read the wind off +the lake by looking at which parts are + + align:start position:0% +the lake by looking at which parts are + + + align:start position:0% +the lake by looking at which parts are +rippled and which parts are glassy but + + align:start position:0% +rippled and which parts are glassy but + + + align:start position:0% +rippled and which parts are glassy but +you still have to decide you know right + + align:start position:0% +you still have to decide you know right + + + align:start position:0% +you still have to decide you know right +are there floating logs in the water are + + align:start position:0% +are there floating logs in the water are + + + align:start position:0% +are there floating logs in the water are +there swimmers are there boats here are + + align:start position:0% +there swimmers are there boats here are + + + align:start position:0% +there swimmers are there boats here are +some unusual skills that you have to + + align:start position:0% +some unusual skills that you have to + + + align:start position:0% +some unusual skills that you have to +have well you might have to have after + + align:start position:0% +have well you might have to have after + + + align:start position:0% +have well you might have to have after +maintenance or to get their plane + + align:start position:0% +maintenance or to get their plane + + + align:start position:0% +maintenance or to get their plane +maintained + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +well + + align:start position:0% + + + + align:start position:0% + +all right so that was straight floats in + + align:start position:0% +all right so that was straight floats in + + + align:start position:0% +all right so that was straight floats in +the grass so at the end of the season + + align:start position:0% +the grass so at the end of the season + + + align:start position:0% +the grass so at the end of the season +you want to get the airplane maintained + + align:start position:0% +you want to get the airplane maintained + + + align:start position:0% +you want to get the airplane maintained +there's not a lot of airplane mechanics + + align:start position:0% +there's not a lot of airplane mechanics + + + align:start position:0% +there's not a lot of airplane mechanics +hanging around the typical lake so you + + align:start position:0% +hanging around the typical lake so you + + + align:start position:0% +hanging around the typical lake so you +just land it on the floats in the grass + + align:start position:0% +just land it on the floats in the grass + + + align:start position:0% +just land it on the floats in the grass +at an airport and what about when you + + align:start position:0% +at an airport and what about when you + + + align:start position:0% +at an airport and what about when you +want to get it out + + align:start position:0% + + + + align:start position:0% + +Oh + + align:start position:0% + + + + align:start position:0% + +you had to get the sound watch that at + + align:start position:0% +you had to get the sound watch that at + + + align:start position:0% +you had to get the sound watch that at +home + + align:start position:0% +home + + + align:start position:0% +home +[Music] + + align:start position:0% + + + + align:start position:0% + +so as I said earlier the problem with + + align:start position:0% +so as I said earlier the problem with + + + align:start position:0% +so as I said earlier the problem with +you know seaplanes is that you know it's + + align:start position:0% +you know seaplanes is that you know it's + + + align:start position:0% +you know seaplanes is that you know it's +just a lot less forgiving than hard + + align:start position:0% +just a lot less forgiving than hard + + + align:start position:0% +just a lot less forgiving than hard +surface runway which is the most + + align:start position:0% +surface runway which is the most + + + align:start position:0% +surface runway which is the most +forgiving environment you can enhance + + align:start position:0% +forgiving environment you can enhance + + + align:start position:0% +forgiving environment you can enhance +that safety with the two pilot crew + + align:start position:0% +that safety with the two pilot crew + + + align:start position:0% +that safety with the two pilot crew +especially an experienced seaplane pilot + + align:start position:0% +especially an experienced seaplane pilot + + + align:start position:0% +especially an experienced seaplane pilot +or there's stuff that'll be on the test + + align:start position:0% +or there's stuff that'll be on the test + + + align:start position:0% +or there's stuff that'll be on the test +you can learn about accident reporting + + align:start position:0% +you can learn about accident reporting + + + align:start position:0% +you can learn about accident reporting +so this is a different part of the + + align:start position:0% +so this is a different part of the + + + align:start position:0% +so this is a different part of the +federal regulations this is the part + + align:start position:0% +federal regulations this is the part + + + align:start position:0% +federal regulations this is the part +that relates the that regulates what the + + align:start position:0% +that relates the that regulates what the + + + align:start position:0% +that relates the that regulates what the +NTS PD NTSB does National Transportation + + align:start position:0% +NTS PD NTSB does National Transportation + + + align:start position:0% +NTS PD NTSB does National Transportation +Safety Board so first they define what + + align:start position:0% +Safety Board so first they define what + + + align:start position:0% +Safety Board so first they define what +an accident is so there has to be you + + align:start position:0% +an accident is so there has to be you + + + align:start position:0% +an accident is so there has to be you +know a serious injury and they define if + + align:start position:0% +know a serious injury and they define if + + + align:start position:0% +know a serious injury and they define if +you go in there they kind of define what + + align:start position:0% +you go in there they kind of define what + + + align:start position:0% +you go in there they kind of define what +a serious injury is and I think + + align:start position:0% +a serious injury is and I think + + + align:start position:0% +a serious injury is and I think +substantial damage to the aircraft if + + align:start position:0% +substantial damage to the aircraft if + + + align:start position:0% +substantial damage to the aircraft if +it's just the landing gear that's a bit + + align:start position:0% +it's just the landing gear that's a bit + + + align:start position:0% +it's just the landing gear that's a bit +trashed I don't think that qualifies if + + align:start position:0% +trashed I don't think that qualifies if + + + align:start position:0% +trashed I don't think that qualifies if +somebody dies within 30 days of the + + align:start position:0% +somebody dies within 30 days of the + + + align:start position:0% +somebody dies within 30 days of the +accident it becomes fatal here's your + + align:start position:0% +accident it becomes fatal here's your + + + align:start position:0% +accident it becomes fatal here's your +here's your definition of serious injury + + align:start position:0% +here's your definition of serious injury + + + align:start position:0% +here's your definition of serious injury +not too much fun you have to immediately + + align:start position:0% +not too much fun you have to immediately + + + align:start position:0% +not too much fun you have to immediately +notify the NTSB if the flight controls + + align:start position:0% +notify the NTSB if the flight controls + + + align:start position:0% +notify the NTSB if the flight controls +malfunction they don't really care if + + align:start position:0% +malfunction they don't really care if + + + align:start position:0% +malfunction they don't really care if +the lycoming our continental piston + + align:start position:0% +the lycoming our continental piston + + + align:start position:0% +the lycoming our continental piston +engine fails in some way but if the + + align:start position:0% +engine fails in some way but if the + + + align:start position:0% +engine fails in some way but if the +flight controls fail and you can't Bank + + align:start position:0% +flight controls fail and you can't Bank + + + align:start position:0% +flight controls fail and you can't Bank +your session or Piper or cirrus that's + + align:start position:0% +your session or Piper or cirrus that's + + + align:start position:0% +your session or Piper or cirrus that's +something they want to hear about if + + align:start position:0% +something they want to hear about if + + + align:start position:0% +something they want to hear about if +more than half of your glass cockpit + + align:start position:0% +more than half of your glass cockpit + + + align:start position:0% +more than half of your glass cockpit +goes dark they want to hear about that + + align:start position:0% + + + + align:start position:0% + +I think 830 . 15 is kind of in in the + + align:start position:0% +I think 830 . 15 is kind of in in the + + + align:start position:0% +I think 830 . 15 is kind of in in the +test something it's those time periods + + align:start position:0% +test something it's those time periods + + + align:start position:0% +test something it's those time periods +like report report within 10 days of the + + align:start position:0% +like report report within 10 days of the + + + align:start position:0% +like report report within 10 days of the +accident oh yeah and your required info + + align:start position:0% +accident oh yeah and your required info + + + align:start position:0% +accident oh yeah and your required info +when notifying okay + + align:start position:0% +when notifying okay + + + align:start position:0% +when notifying okay +so the bottom line on seaplanes is that + + align:start position:0% +so the bottom line on seaplanes is that + + + align:start position:0% +so the bottom line on seaplanes is that +it does combine you know the hazards of + + align:start position:0% +it does combine you know the hazards of + + + align:start position:0% +it does combine you know the hazards of +a boat and a plane and therefore you + + align:start position:0% +a boat and a plane and therefore you + + + align:start position:0% +a boat and a plane and therefore you +need the skills of both a sailor and a + + align:start position:0% +need the skills of both a sailor and a + + + align:start position:0% +need the skills of both a sailor and a +pilot + + align:start position:0% +pilot + + + align:start position:0% +pilot +to manage those hazards on the other + + align:start position:0% +to manage those hazards on the other + + + align:start position:0% +to manage those hazards on the other +hand I think it's a lot of fun you know + + align:start position:0% +hand I think it's a lot of fun you know + + + align:start position:0% +hand I think it's a lot of fun you know +when the icon first came out at $100,000 + + align:start position:0% +when the icon first came out at $100,000 + + + align:start position:0% +when the icon first came out at $100,000 +and change I thought well this would be + + align:start position:0% +and change I thought well this would be + + + align:start position:0% +and change I thought well this would be +great well you just get one of these + + align:start position:0% +great well you just get one of these + + + align:start position:0% +great well you just get one of these +we'll split it four ways we'll keep it + + align:start position:0% +we'll split it four ways we'll keep it + + + align:start position:0% +we'll split it four ways we'll keep it +at Hanscom and then you know we'll go up + + align:start position:0% +at Hanscom and then you know we'll go up + + + align:start position:0% +at Hanscom and then you know we'll go up +for a 15-minute flight to New Hampshire + + align:start position:0% +for a 15-minute flight to New Hampshire + + + align:start position:0% +for a 15-minute flight to New Hampshire +slash and - come back and it'll be + + align:start position:0% +slash and - come back and it'll be + + + align:start position:0% +slash and - come back and it'll be +really cool now that it's a four hundred + + align:start position:0% +really cool now that it's a four hundred + + + align:start position:0% +really cool now that it's a four hundred +thousand dollar airplane you know it's + + align:start position:0% +thousand dollar airplane you know it's + + + align:start position:0% +thousand dollar airplane you know it's +not enough it's the question is let's go + + align:start position:0% +not enough it's the question is let's go + + + align:start position:0% +not enough it's the question is let's go +back to that slide + + align:start position:0% +back to that slide + + + align:start position:0% +back to that slide +yeah file report within seven days if an + + align:start position:0% +yeah file report within seven days if an + + + align:start position:0% +yeah file report within seven days if an +aircraft is overdue so that means you + + align:start position:0% +aircraft is overdue so that means you + + + align:start position:0% +aircraft is overdue so that means you +expected an airplane to come back from + + align:start position:0% +expected an airplane to come back from + + + align:start position:0% +expected an airplane to come back from +the fishing camp in Alaska and it hasn't + + align:start position:0% +the fishing camp in Alaska and it hasn't + + + align:start position:0% +the fishing camp in Alaska and it hasn't +returned so you don't know if it's + + align:start position:0% +returned so you don't know if it's + + + align:start position:0% +returned so you don't know if it's +crashed or not that was like me remember + + align:start position:0% +crashed or not that was like me remember + + + align:start position:0% +crashed or not that was like me remember +I told you that story about landing at + + align:start position:0% +I told you that story about landing at + + + align:start position:0% +I told you that story about landing at +PDK in Atlanta and I didn't forgot to + + align:start position:0% +PDK in Atlanta and I didn't forgot to + + + align:start position:0% +PDK in Atlanta and I didn't forgot to +close my flight plan and so my my + + align:start position:0% +close my flight plan and so my my + + + align:start position:0% +close my flight plan and so my my +diamond star was considered overdue and + + align:start position:0% +diamond star was considered overdue and + + + align:start position:0% +diamond star was considered overdue and +I kept rejecting calls from an + + align:start position:0% +I kept rejecting calls from an + + + align:start position:0% +I kept rejecting calls from an +unfamiliar phone number my proudest + + align:start position:0% +unfamiliar phone number my proudest + + + align:start position:0% +unfamiliar phone number my proudest +moment all right so insurance is kind of + + align:start position:0% +moment all right so insurance is kind of + + + align:start position:0% +moment all right so insurance is kind of +expensive as any other de specially for + + align:start position:0% +expensive as any other de specially for + + + align:start position:0% +expensive as any other de specially for +the amphibs Strait an airplane on + + align:start position:0% +the amphibs Strait an airplane on + + + align:start position:0% +the amphibs Strait an airplane on +straight flows isn't that much more + + align:start position:0% +straight flows isn't that much more + + + align:start position:0% +straight flows isn't that much more +expensive to insure than a regular + + align:start position:0% +expensive to insure than a regular + + + align:start position:0% +expensive to insure than a regular +airplane actually that's a great way to + + align:start position:0% +airplane actually that's a great way to + + + align:start position:0% +airplane actually that's a great way to +evaluate risk if an insurance company is + + align:start position:0% +evaluate risk if an insurance company is + + + align:start position:0% +evaluate risk if an insurance company is +willing to write a policy first that's + + align:start position:0% +willing to write a policy first that's + + + align:start position:0% +willing to write a policy first that's +not on floats it can't be all that can't + + align:start position:0% +not on floats it can't be all that can't + + + align:start position:0% +not on floats it can't be all that can't +be all that dangerous but like I said + + align:start position:0% +be all that dangerous but like I said + + + align:start position:0% +be all that dangerous but like I said +the military has decided what's do most + + align:start position:0% +the military has decided what's do most + + + align:start position:0% +the military has decided what's do most +of the things we used to do with sea + + align:start position:0% +of the things we used to do with sea + + + align:start position:0% +of the things we used to do with sea +planes with helicopters question + + align:start position:0% + + + + align:start position:0% + +so aren't sure we've met personal + + align:start position:0% +so aren't sure we've met personal + + + align:start position:0% +so aren't sure we've met personal +insurance so I don't belong but we + + align:start position:0% +insurance so I don't belong but we + + + align:start position:0% +insurance so I don't belong but we +ourselves are + + align:start position:0% +ourselves are + + + align:start position:0% + +I think question is just your like + + align:start position:0% +I think question is just your like + + + align:start position:0% +I think question is just your like +regular medical insurance cover an + + align:start position:0% +regular medical insurance cover an + + + align:start position:0% +regular medical insurance cover an +injury from plying sure yeah there's no + + align:start position:0% +injury from plying sure yeah there's no + + + align:start position:0% +injury from plying sure yeah there's no +exclusion for that I think sometimes if + + align:start position:0% +exclusion for that I think sometimes if + + + align:start position:0% +exclusion for that I think sometimes if +you get like an umbrella liability + + align:start position:0% +you get like an umbrella liability + + + align:start position:0% +you get like an umbrella liability +policy they say well that's great but + + align:start position:0% +policy they say well that's great but + + + align:start position:0% +policy they say well that's great but +we're not gonna like to add five million + + align:start position:0% +we're not gonna like to add five million + + + align:start position:0% +we're not gonna like to add five million +dollars if you injure somebody with your + + align:start position:0% +dollars if you injure somebody with your + + + align:start position:0% +dollars if you injure somebody with your +Cessna so they can have exclusions AOPA + + align:start position:0% +Cessna so they can have exclusions AOPA + + + align:start position:0% +Cessna so they can have exclusions AOPA +has a big insurance business actually + + align:start position:0% +has a big insurance business actually + + + align:start position:0% +has a big insurance business actually +selling life insurance at pretty + + align:start position:0% +selling life insurance at pretty + + + align:start position:0% +selling life insurance at pretty +reasonable rates to pilots so there + + align:start position:0% +reasonable rates to pilots so there + + + align:start position:0% +reasonable rates to pilots so there +again that tells you you know when your + + align:start position:0% +again that tells you you know when your + + + align:start position:0% +again that tells you you know when your +friend says you know you're stupid why + + align:start position:0% +friend says you know you're stupid why + + + align:start position:0% +friend says you know you're stupid why +would you fly a Piper or a Cessna you + + align:start position:0% +would you fly a Piper or a Cessna you + + + align:start position:0% +would you fly a Piper or a Cessna you +know that thing's old it doesn't look + + align:start position:0% +know that thing's old it doesn't look + + + align:start position:0% +know that thing's old it doesn't look +safe you can say well like insurance + + align:start position:0% +safe you can say well like insurance + + + align:start position:0% +safe you can say well like insurance +companies aren't stupid and they have a + + align:start position:0% +companies aren't stupid and they have a + + + align:start position:0% +companies aren't stupid and they have a +huge business marketing life insurance + + align:start position:0% +huge business marketing life insurance + + + align:start position:0% +huge business marketing life insurance +to the members of AOPA who are all + + align:start position:0% +to the members of AOPA who are all + + + align:start position:0% +to the members of AOPA who are all +flying little airplanes like this and + + align:start position:0% +flying little airplanes like this and + + + align:start position:0% +flying little airplanes like this and +you know it's only a 10 percent higher + + align:start position:0% +you know it's only a 10 percent higher + + + align:start position:0% +you know it's only a 10 percent higher +rate than you know what you can get in + + align:start position:0% +rate than you know what you can get in + + + align:start position:0% +rate than you know what you can get in +the market elsewhere of course pilots + + align:start position:0% +the market elsewhere of course pilots + + + align:start position:0% +the market elsewhere of course pilots +are healthier than the that's that's + + align:start position:0% +are healthier than the that's that's + + + align:start position:0% +are healthier than the that's that's +that's one issue right since pilots by + + align:start position:0% +that's one issue right since pilots by + + + align:start position:0% +that's one issue right since pilots by +definition have passed a medical exam + + align:start position:0% +definition have passed a medical exam + + + align:start position:0% +definition have passed a medical exam +they tend to be a little bit healthier + + align:start position:0% +they tend to be a little bit healthier + + + align:start position:0% +they tend to be a little bit healthier +than average same reason like the + + align:start position:0% +than average same reason like the + + + align:start position:0% +than average same reason like the +military the death rate of people who + + align:start position:0% +military the death rate of people who + + + align:start position:0% +military the death rate of people who +serve in the military is quite a bit + + align:start position:0% +serve in the military is quite a bit + + + align:start position:0% +serve in the military is quite a bit +lower than the death rate of the same + + align:start position:0% +lower than the death rate of the same + + + align:start position:0% +lower than the death rate of the same +age people who are in the civilian + + align:start position:0% +age people who are in the civilian + + + align:start position:0% +age people who are in the civilian +workforce + + align:start position:0% +workforce + + + align:start position:0% +workforce +partly because not that many of them are + + align:start position:0% +partly because not that many of them are + + + align:start position:0% +partly because not that many of them are +actually you know in combat and partly + + align:start position:0% +actually you know in combat and partly + + + align:start position:0% +actually you know in combat and partly +because the military rejects people who + + align:start position:0% +because the military rejects people who + + + align:start position:0% +because the military rejects people who +are unhealthy so you're not going to die + + align:start position:0% +are unhealthy so you're not going to die + + + align:start position:0% +are unhealthy so you're not going to die +of cancer at age 23 if you're in the + + align:start position:0% +of cancer at age 23 if you're in the + + + align:start position:0% +of cancer at age 23 if you're in the +military because they would have not let + + align:start position:0% +military because they would have not let + + + align:start position:0% +military because they would have not let +you enlist probably if they saw that you + + align:start position:0% +you enlist probably if they saw that you + + + align:start position:0% +you enlist probably if they saw that you +were suffering from the beginning stages + + align:start position:0% +were suffering from the beginning stages + + + align:start position:0% +were suffering from the beginning stages +of cancer all right light sport flying + + align:start position:0% +of cancer all right light sport flying + + + align:start position:0% +of cancer all right light sport flying +boats array is fun this is a real one + + align:start position:0% +boats array is fun this is a real one + + + align:start position:0% +boats array is fun this is a real one +there's 700 of these out there and they + + align:start position:0% +there's 700 of these out there and they + + + align:start position:0% +there's 700 of these out there and they +sell it as a kit and they also sell it + + align:start position:0% +sell it as a kit and they also sell it + + + align:start position:0% +sell it as a kit and they also sell it +as a built airplane so here it is look + + align:start position:0% +as a built airplane so here it is look + + + align:start position:0% +as a built airplane so here it is look +how much fun some somebody put one of + + align:start position:0% +how much fun some somebody put one of + + + align:start position:0% +how much fun some somebody put one of +these on a yacht and flew it in all + + align:start position:0% +these on a yacht and flew it in all + + + align:start position:0% +these on a yacht and flew it in all +different parts of the world you know + + align:start position:0% +different parts of the world you know + + + align:start position:0% +different parts of the world you know +they would take off I guess they would + + align:start position:0% +they would take off I guess they would + + + align:start position:0% +they would take off I guess they would +winch it down into the water take off + + align:start position:0% +winch it down into the water take off + + + align:start position:0% +winch it down into the water take off +fly around and then winch it back up and + + align:start position:0% +fly around and then winch it back up and + + + align:start position:0% +fly around and then winch it back up and +I think they were in some fairly open + + align:start position:0% +I think they were in some fairly open + + + align:start position:0% +I think they were in some fairly open +oceans at the time none of the things + + align:start position:0% +oceans at the time none of the things + + + align:start position:0% +oceans at the time none of the things +survived so that's pretty cool they + + align:start position:0% +survived so that's pretty cool they + + + align:start position:0% +survived so that's pretty cool they +stuff a Garmin g3x glass cockpit in + + align:start position:0% +stuff a Garmin g3x glass cockpit in + + + align:start position:0% +stuff a Garmin g3x glass cockpit in +there that's the same that the things + + align:start position:0% +there that's the same that the things + + + align:start position:0% +there that's the same that the things +that Gabe gamebird has the light sport + + align:start position:0% +that Gabe gamebird has the light sport + + + align:start position:0% +that Gabe gamebird has the light sport +folks have a lot of flexibility it has a + + align:start position:0% +folks have a lot of flexibility it has a + + + align:start position:0% +folks have a lot of flexibility it has a +Rotax engine which is conventional the + + align:start position:0% +Rotax engine which is conventional the + + + align:start position:0% +Rotax engine which is conventional the +icon a5 is the airplane see look look at + + align:start position:0% +icon a5 is the airplane see look look at + + + align:start position:0% +icon a5 is the airplane see look look at +Oshkosh there there booth is always + + align:start position:0% +Oshkosh there there booth is always + + + align:start position:0% +Oshkosh there there booth is always +packed people love it people want it and + + align:start position:0% +packed people love it people want it and + + + align:start position:0% +packed people love it people want it and +it's one of the few airplanes that's + + align:start position:0% +it's one of the few airplanes that's + + + align:start position:0% +it's one of the few airplanes that's +marketed to people that don't have any + + align:start position:0% +marketed to people that don't have any + + + align:start position:0% +marketed to people that don't have any +flying experience + + align:start position:0% +flying experience + + + align:start position:0% +flying experience +I wrote a review of it in 2010 saying + + align:start position:0% +I wrote a review of it in 2010 saying + + + align:start position:0% +I wrote a review of it in 2010 saying +that it would be available until 2014 I + + align:start position:0% +that it would be available until 2014 I + + + align:start position:0% +that it would be available until 2014 I +think it had been originally promised + + align:start position:0% +think it had been originally promised + + + align:start position:0% +think it had been originally promised +for you know 2012 so it's just kind of + + align:start position:0% +for you know 2012 so it's just kind of + + + align:start position:0% +for you know 2012 so it's just kind of +coming out but these composite plants + + align:start position:0% +coming out but these composite plants + + + align:start position:0% +coming out but these composite plants +are hard to manufacture I talked to the + + align:start position:0% +are hard to manufacture I talked to the + + + align:start position:0% +are hard to manufacture I talked to the +gamebird guys they said they spend 500 + + align:start position:0% +gamebird guys they said they spend 500 + + + align:start position:0% +gamebird guys they said they spend 500 +hours 500 person hours prepping the + + align:start position:0% +hours 500 person hours prepping the + + + align:start position:0% +hours 500 person hours prepping the +airplane to be painted just like sanding + + align:start position:0% +airplane to be painted just like sanding + + + align:start position:0% +airplane to be painted just like sanding +and smoothing everything to be painted + + align:start position:0% +and smoothing everything to be painted + + + align:start position:0% +and smoothing everything to be painted +so I think it's just very hard to make + + align:start position:0% +so I think it's just very hard to make + + + align:start position:0% +so I think it's just very hard to make +these things at an economical price I + + align:start position:0% +these things at an economical price I + + + align:start position:0% +these things at an economical price I +still don't have sound I don't think do + + align:start position:0% +still don't have sound I don't think do + + + align:start position:0% +still don't have sound I don't think do +we here's my review of the plane I made + + align:start position:0% +we here's my review of the plane I made + + + align:start position:0% +we here's my review of the plane I made +this little video that was fun well I + + align:start position:0% +this little video that was fun well I + + + align:start position:0% +this little video that was fun well I +thought it was fun I'm sure Ikon doesn't + + align:start position:0% +thought it was fun I'm sure Ikon doesn't + + + align:start position:0% +thought it was fun I'm sure Ikon doesn't +think it's fun alright questions about + + align:start position:0% +think it's fun alright questions about + + + align:start position:0% +think it's fun alright questions about +sea planes + + align:start position:0% + + + + align:start position:0% + +who wants one who want who would buy an + + align:start position:0% +who wants one who want who would buy an + + + align:start position:0% +who wants one who want who would buy an +icon if it were reasonably priced + + align:start position:0% + + + + align:start position:0% + +yeah the question is you know what would + + align:start position:0% +yeah the question is you know what would + + + align:start position:0% +yeah the question is you know what would +buy in my opinion B of landing in the + + align:start position:0% +buy in my opinion B of landing in the + + + align:start position:0% +buy in my opinion B of landing in the +Great Lakes I think people do use do a + + align:start position:0% +Great Lakes I think people do use do a + + + align:start position:0% +Great Lakes I think people do use do a +lot of flying of sea planes up in the + + align:start position:0% +lot of flying of sea planes up in the + + + align:start position:0% +lot of flying of sea planes up in the +Great Lakes but there again you know the + + align:start position:0% +Great Lakes but there again you know the + + + align:start position:0% +Great Lakes but there again you know the +Great Lakes there are harbors there are + + align:start position:0% +Great Lakes there are harbors there are + + + align:start position:0% +Great Lakes there are harbors there are +column or areas I think they're not + + align:start position:0% +column or areas I think they're not + + + align:start position:0% +column or areas I think they're not +really landing in the middle of the + + align:start position:0% +really landing in the middle of the + + + align:start position:0% +really landing in the middle of the +Great Lake and then they don't say like + + align:start position:0% +Great Lake and then they don't say like + + + align:start position:0% +Great Lake and then they don't say like +I just want to go to the middle of Lake + + align:start position:0% +I just want to go to the middle of Lake + + + align:start position:0% +I just want to go to the middle of Lake +Superior and fish off the float for a + + align:start position:0% +Superior and fish off the float for a + + + align:start position:0% +Superior and fish off the float for a +while + + align:start position:0% +while + + + align:start position:0% +while +they're going to some destination and by + + align:start position:0% +they're going to some destination and by + + + align:start position:0% +they're going to some destination and by +definition you know the destination will + + align:start position:0% +definition you know the destination will + + + align:start position:0% +definition you know the destination will +have a calmer area for for boats to hang + + align:start position:0% +have a calmer area for for boats to hang + + + align:start position:0% +have a calmer area for for boats to hang +out and it's I think there's actually a + + align:start position:0% +out and it's I think there's actually a + + + align:start position:0% +out and it's I think there's actually a +commercial seaplane service that's + + align:start position:0% +commercial seaplane service that's + + + align:start position:0% +commercial seaplane service that's +starting up between Manhattan and Boston + + align:start position:0% +starting up between Manhattan and Boston + + + align:start position:0% +starting up between Manhattan and Boston +so you'll you'll go to the there's a + + align:start position:0% +so you'll you'll go to the there's a + + + align:start position:0% +so you'll you'll go to the there's a +seaplane I should have mentioned this + + align:start position:0% +seaplane I should have mentioned this + + + align:start position:0% +seaplane I should have mentioned this +for helicopters they're held at pads all + + align:start position:0% +for helicopters they're held at pads all + + + align:start position:0% +for helicopters they're held at pads all +around Manhattan so you can actually go + + align:start position:0% +around Manhattan so you can actually go + + + align:start position:0% +around Manhattan so you can actually go +to the downtown Wall Street heliport + + align:start position:0% +to the downtown Wall Street heliport + + + align:start position:0% +to the downtown Wall Street heliport +land it used to be really cheap it was + + align:start position:0% +land it used to be really cheap it was + + + align:start position:0% +land it used to be really cheap it was +$75 an hour for parking I think or maybe + + align:start position:0% +$75 an hour for parking I think or maybe + + + align:start position:0% +$75 an hour for parking I think or maybe +25 it was I don't know it was it was not + + align:start position:0% +25 it was I don't know it was it was not + + + align:start position:0% +25 it was I don't know it was it was not +that much more than parking in a car go + + align:start position:0% +that much more than parking in a car go + + + align:start position:0% +that much more than parking in a car go +and have lunch now they've leased those + + align:start position:0% +and have lunch now they've leased those + + + align:start position:0% +and have lunch now they've leased those +helmet pads to some government crony + + align:start position:0% +helmet pads to some government crony + + + align:start position:0% +helmet pads to some government crony +monopoly that owns all three of them and + + align:start position:0% +monopoly that owns all three of them and + + + align:start position:0% +monopoly that owns all three of them and +they crank the rates up by a factor of + + align:start position:0% +they crank the rates up by a factor of + + + align:start position:0% +they crank the rates up by a factor of +four on you know immediately but anyway + + align:start position:0% +four on you know immediately but anyway + + + align:start position:0% +four on you know immediately but anyway +they I don't know if it's the same + + align:start position:0% +they I don't know if it's the same + + + align:start position:0% +they I don't know if it's the same +company but they have a seaplane a + + align:start position:0% +company but they have a seaplane a + + + align:start position:0% +company but they have a seaplane a +public seaplane port they're on the East + + align:start position:0% +public seaplane port they're on the East + + + align:start position:0% +public seaplane port they're on the East +River and this I think it's a cape air + + align:start position:0% +River and this I think it's a cape air + + + align:start position:0% +River and this I think it's a cape air +affiliate maybe that's going to start + + align:start position:0% +affiliate maybe that's going to start + + + align:start position:0% +affiliate maybe that's going to start +operating downtown to downtown and + + align:start position:0% +operating downtown to downtown and + + + align:start position:0% +operating downtown to downtown and +assessment caravan on floats + + align:start position:0% + + + + align:start position:0% + +you \ No newline at end of file diff --git a/yauQ7o1ZAAw.txt b/yauQ7o1ZAAw.txt new file mode 100644 index 0000000000000000000000000000000000000000..39a89003cd8a86a466f65528d2f1dccf41aa8220 --- /dev/null +++ b/yauQ7o1ZAAw.txt @@ -0,0 +1,264 @@ +Let's start by redrawing and simplifying the +Beta data path so that it will be easier to + +reason about when we add pipelining. + +The first simplification is to focus on sequential +execution and so leave out the branch addressing + +and PC mux logic. + +Our simplified Beta always executes the next +instruction from PC+4. + +We'll add back the branch and jump logic when +we discuss control hazards. + +The second simplification is to have the register +file appear twice in the diagram so that we + +can tease apart the read and write operations +that occur at different stages of instruction + +execution. + +The top Register File shows the combinational +read ports, used to when reading the register + +operands in the RF stage. + +The bottom Register File shows the clocked +write port, used to write the result into + +the destination register at the end of the +WB stage. + +Physically, there's only one set of 32 registers, +we've just drawn the read and write circuity + +as separate components in the diagram. + +If we add pipeline registers to the simplified +diagram, we see that execution proceeds through + +the five stages from top to bottom. + +If we consider execution of instruction sequences +with no data hazards, information is flowing + +down the pipeline and the pipeline will correctly +overlap the execution of all the instructions + +in the pipeline. + +The diagram shows the components needed to +implement each of the five stages. + +The IF stage contains the program counter +and the main memory interface for fetching + +instructions. + +The RF stage has the register file and operand +multiplexers. + +The ALU stage uses the operands and computes +the result. + +The MEM stage handles the memory access for +load and store operations. + +And the WB stage writes the result into the +destination register. + +In each clock cycle, each stage does its part +in the execution of a particular instruction. + +In a given clock cycle, there are five instructions +in the pipeline. + +Note that data accesses to main memory span +almost two clock cycles. + +Data accesses are initiated at the beginning +of the MEM stage and returning data is only + +needed just before the end of the WB stage. + +The memory is itself pipelined and can simultaneously +finish the access from an earlier instruction + +while starting an access for the next instruction. + +This simplified diagram isn't showing how +the control logic is split across the pipeline + +stages. + +How does that work? + +Note that we've included instruction registers +as part of each pipeline stage, so that each + +stage can compute the control signals it needs +from its instruction register. + +The encoded instruction is simply passed from +one stage to the next as the instruction flows + +through the pipeline.. + +Each stage computes its control signals from +the opcode field of its instruction register. + +The RF stage needs the RA, RB, and literal +fields from its instruction register. + +And the WB stage needs the RC field from its +instruction register. + +The required logic is very similar to the +unpipelined implementation, it's just been + +split up and moved to the appropriate pipeline +stage. + +We'll see that we will have to add some additional +control logic to deal correctly with pipeline + +hazards. + +Our simplified diagram isn't so simple anymore! + +To see how the pipeline works, let's follow +along as it executes this sequence of six + +instructions. + +Note that the instructions are reading and +writing from different registers, so there + +are no potential data hazards. + +And there are no branches and jumps, so there +are no potential control hazards. + +Since there are no potential hazards, the +instruction executions can be overlapped and + +their overlapped execution in the pipeline +will work correctly. + +Okay, here we go! + +During cycle 1, the IF stage sends the value +from the program counter to main memory to + +fetch the first instruction (the green LD +instruction), which will be stored in the + +RF-stage instruction register at the end of +the cycle. + +Meanwhile, it's also computing PC+4, which +will be the next value of the program counter. + +We've colored the next value blue to indicate +that it's the address of the blue instruction + +in the sequence. + +We'll add the appropriately colored label +on the right of each pipeline stage to indicate + +which instruction the stage is processing. + +At the start of cycle 2, we see that values +in the PC and instruction registers for the + +RF stage now correspond to the green instruction. + +During the cycle the register file will be +reading the register operands, in this case + +R1, which is needed for the green instruction. + +Since the green instruction is a LD, ASEL +is 0 and BSEL is 1, selecting the appropriate + +values to be written into the A and B operand +registers at the end of the cycle. + +Concurrently, the IF stage is fetching the +blue instruction from main memory and computing + +an updated PC value for the next cycle. + +In cycle 3, the green instruction is now in +the ALU stage, where the ALU is adding the + +values in its operand registers (in this case +the value of R1 and the constant 4) and the + +result will be stored in Y_MEM register at +the end of the cycle. + +In cycle 4, we're overlapping execution of +four instructions. + +The MEM stage initiates a memory read for +the green LD instruction. + +Note that the read data will first become +available in the WB stage - it's not available + +to CPU in the current clock cycle. + +In cycle 5, the results of the main memory +read initiated in cycle 4 are available for + +writing to the register file in the WB stage. + +So execution of the green LD instruction will +be complete when the memory data is written + +to R2 at the end of cycle 5. + +Meanwhile, the MEM stage is initiating a memory +read for the blue LD instruction. + +The pipeline continues to complete successive +instructions in successive clock cycles. + +The latency for a particular instruction is +5 clock cycles. + +The throughput of the pipelined CPU is 1 instruction/cycle. + +This is the same as the unpipelined implementation, +except that the clock period is shorter because + +each pipeline stage has fewer components. + +Note that the effects of the green LD, i.e., +filling R2 with a new value, don't happen + +until the rising edge of the clock at the +end of cycle 5. + +In other words, the results of the green LD +aren't available to other instructions until + +cycle 6. + +If there were instructions in the pipeline +that read R2 before cycle 6, they would have + +gotten an old value! + +This is an example of a data hazard. + +Not a problem for us, since our instruction +sequence didn't trigger this data hazard. + +Tackling data hazards is our next task. \ No newline at end of file diff --git a/yoq0ENMiR4w.txt b/yoq0ENMiR4w.txt new file mode 100644 index 0000000000000000000000000000000000000000..f8d4b7ce939d843a00057d623bfb5b56dfb72d43 --- /dev/null +++ b/yoq0ENMiR4w.txt @@ -0,0 +1,8763 @@ +align:start position:0% + +let me um continue with the eslm PC + + align:start position:0% +let me um continue with the eslm PC + + + align:start position:0% +let me um continue with the eslm PC +model in fact I want to I Rush a little + + align:start position:0% +model in fact I want to I Rush a little + + + align:start position:0% +model in fact I want to I Rush a little +because I was over excited with the svb + + align:start position:0% +because I was over excited with the svb + + + align:start position:0% +because I was over excited with the svb +bank event H and and I want to make sure + + align:start position:0% +bank event H and and I want to make sure + + + align:start position:0% +bank event H and and I want to make sure +that you + + align:start position:0% +that you + + + align:start position:0% +that you +certainly understand this this mle it's + + align:start position:0% +certainly understand this this mle it's + + + align:start position:0% +certainly understand this this mle it's +going to be very + + align:start position:0% +going to be very + + + align:start position:0% +going to be very +important and I think it's one of the + + align:start position:0% +important and I think it's one of the + + + align:start position:0% +important and I think it's one of the +most important moles in in this course + + align:start position:0% +most important moles in in this course + + + align:start position:0% +most important moles in in this course +as I said + + align:start position:0% +as I said + + + align:start position:0% +as I said +before also I want to use a little bit + + align:start position:0% +before also I want to use a little bit + + + align:start position:0% +before also I want to use a little bit +more the this Mo itself to explain what + + align:start position:0% +more the this Mo itself to explain what + + + align:start position:0% +more the this Mo itself to explain what +is going on right now today we got hit + + align:start position:0% +is going on right now today we got hit + + + align:start position:0% +is going on right now today we got hit +by a second shock from the financial + + align:start position:0% +by a second shock from the financial + + + align:start position:0% +by a second shock from the financial +system and uh so so it's getting it's + + align:start position:0% +system and uh so so it's getting it's + + + align:start position:0% +system and uh so so it's getting it's +getting exciting these days so let me + + align:start position:0% +getting exciting these days so let me + + + align:start position:0% +getting exciting these days so let me +skip all this and remind you that that's + + align:start position:0% +skip all this and remind you that that's + + + align:start position:0% +skip all this and remind you that that's +what we we that's that's the ISL MPC + + align:start position:0% +what we we that's that's the ISL MPC + + + align:start position:0% +what we we that's that's the ISL MPC +model which I said is nothing else and + + align:start position:0% +model which I said is nothing else and + + + align:start position:0% +model which I said is nothing else and +just integrating the islm analysis with + + align:start position:0% +just integrating the islm analysis with + + + align:start position:0% +just integrating the islm analysis with +the Philips curve this is the part and I + + align:start position:0% +the Philips curve this is the part and I + + + align:start position:0% +the Philips curve this is the part and I +said and at this point I will follow the + + align:start position:0% +said and at this point I will follow the + + + align:start position:0% +said and at this point I will follow the +book and and assume that the central + + align:start position:0% +book and and assume that the central + + + align:start position:0% +book and and assume that the central +bank can control the real interest rate + + align:start position:0% +bank can control the real interest rate + + + align:start position:0% +bank can control the real interest rate +rather than the nominal interest rate + + align:start position:0% +rather than the nominal interest rate + + + align:start position:0% +rather than the nominal interest rate +which is what really controls in + + align:start position:0% +which is what really controls in + + + align:start position:0% +which is what really controls in +practice H but I'm going to make that + + align:start position:0% +practice H but I'm going to make that + + + align:start position:0% +practice H but I'm going to make that +assumption so the pictures have less + + align:start position:0% +assumption so the pictures have less + + + align:start position:0% +assumption so the pictures have less +curves moving around when when things + + align:start position:0% +curves moving around when when things + + + align:start position:0% +curves moving around when when things +are mov moving H as when we do Dynamics + + align:start position:0% +are mov moving H as when we do Dynamics + + + align:start position:0% +are mov moving H as when we do Dynamics +okay but that's just a eslm nothing + + align:start position:0% +okay but that's just a eslm nothing + + + align:start position:0% +okay but that's just a eslm nothing +different um then we look at the Philips + + align:start position:0% +different um then we look at the Philips + + + align:start position:0% +different um then we look at the Philips +curve and I said well we can we can uh I + + align:start position:0% +curve and I said well we can we can uh I + + + align:start position:0% +curve and I said well we can we can uh I +this is not very useful because you know + + align:start position:0% +this is not very useful because you know + + + align:start position:0% +this is not very useful because you know +in the as part I have output here and in + + align:start position:0% +in the as part I have output here and in + + + align:start position:0% +in the as part I have output here and in +the Philips curves I have inflation but + + align:start position:0% +the Philips curves I have inflation but + + + align:start position:0% +the Philips curves I have inflation but +then I have an employment and I don't + + align:start position:0% +then I have an employment and I don't + + + align:start position:0% +then I have an employment and I don't +want to be carrying around sort of three + + align:start position:0% +want to be carrying around sort of three + + + align:start position:0% +want to be carrying around sort of three +variables endogenous variables + + align:start position:0% +variables endogenous variables + + + align:start position:0% +variables endogenous variables +ER and and and so it's you know it's + + align:start position:0% +ER and and and so it's you know it's + + + align:start position:0% +ER and and and so it's you know it's +difficult to diagrams in in three + + align:start position:0% +difficult to diagrams in in three + + + align:start position:0% +difficult to diagrams in in three +dimension is everything less clear so + + align:start position:0% +dimension is everything less clear so + + + align:start position:0% +dimension is everything less clear so +I'm going to replace H this unemployment + + align:start position:0% +I'm going to replace H this unemployment + + + align:start position:0% +I'm going to replace H this unemployment +here for for output and it's very easy + + align:start position:0% +here for for output and it's very easy + + + align:start position:0% +here for for output and it's very easy +to do that with the production function + + align:start position:0% +to do that with the production function + + + align:start position:0% +to do that with the production function +we have because output is just equal to + + align:start position:0% +we have because output is just equal to + + + align:start position:0% +we have because output is just equal to +employment and employment is just equal + + align:start position:0% +employment and employment is just equal + + + align:start position:0% +employment and employment is just equal +to the labor force time one minus the + + align:start position:0% +to the labor force time one minus the + + + align:start position:0% +to the labor force time one minus the +rate of unemployment and we could Define + + align:start position:0% +rate of unemployment and we could Define + + + align:start position:0% +rate of unemployment and we could Define +a concept of potential output as simply + + align:start position:0% +a concept of potential output as simply + + + align:start position:0% +a concept of potential output as simply +that output that happens when employment + + align:start position:0% +that output that happens when employment + + + align:start position:0% +that output that happens when employment +is equal to the Natural level of + + align:start position:0% +is equal to the Natural level of + + + align:start position:0% +is equal to the Natural level of +employment which is equal to the labor + + align:start position:0% +employment which is equal to the labor + + + align:start position:0% +employment which is equal to the labor +force Time 1 minus the natural rate of + + align:start position:0% +force Time 1 minus the natural rate of + + + align:start position:0% +force Time 1 minus the natural rate of +unemployment and taking the difference + + align:start position:0% +unemployment and taking the difference + + + align:start position:0% +unemployment and taking the difference +subtracting the second line from the + + align:start position:0% +subtracting the second line from the + + + align:start position:0% +subtracting the second line from the +first one you get a concept that is used + + align:start position:0% +first one you get a concept that is used + + + align:start position:0% +first one you get a concept that is used +very frequently in microeconomics which + + align:start position:0% +very frequently in microeconomics which + + + align:start position:0% +very frequently in microeconomics which +is called is a concept of the output gap + + align:start position:0% +is called is a concept of the output gap + + + align:start position:0% +is called is a concept of the output gap +an output Gap refers to the difference + + align:start position:0% +an output Gap refers to the difference + + + align:start position:0% +an output Gap refers to the difference +between actual output and potential + + align:start position:0% +between actual output and potential + + + align:start position:0% +between actual output and potential +output in which potential output is + + align:start position:0% +output in which potential output is + + + align:start position:0% +output in which potential output is +nothing else of the level of output that + + align:start position:0% +nothing else of the level of output that + + + align:start position:0% +nothing else of the level of output that +you get when employment when an + + align:start position:0% +you get when employment when an + + + align:start position:0% +you get when employment when an +employment is at the natural rate of an + + align:start position:0% +employment is at the natural rate of an + + + align:start position:0% +employment is at the natural rate of an +employment + + align:start position:0% +employment + + + align:start position:0% +employment +so we get this output Gap is related to + + align:start position:0% +so we get this output Gap is related to + + + align:start position:0% +so we get this output Gap is related to +the employment gap and now we can + + align:start position:0% +the employment gap and now we can + + + align:start position:0% +the employment gap and now we can +replace the employment gap from here + + align:start position:0% +replace the employment gap from here + + + align:start position:0% +replace the employment gap from here +with the output Gap and we end up with a + + align:start position:0% +with the output Gap and we end up with a + + + align:start position:0% +with the output Gap and we end up with a +Philip Cur in the space of inflation and + + align:start position:0% +Philip Cur in the space of inflation and + + + align:start position:0% +Philip Cur in the space of inflation and +output gap which is something we can + + align:start position:0% +output gap which is something we can + + + align:start position:0% +output gap which is something we can +integrate very easily withm model that + + align:start position:0% +integrate very easily withm model that + + + align:start position:0% +integrate very easily withm model that +has output in it okay so that's H so the + + align:start position:0% +has output in it okay so that's H so the + + + align:start position:0% +has output in it okay so that's H so the +snpc model is + + align:start position:0% +snpc model is + + + align:start position:0% +snpc model is +really combining this equation with that + + align:start position:0% +really combining this equation with that + + + align:start position:0% +really combining this equation with that +equation and some model about expected + + align:start position:0% +equation and some model about expected + + + align:start position:0% +equation and some model about expected +inflation that's what the MPC model is + + align:start position:0% +inflation that's what the MPC model is + + + align:start position:0% +inflation that's what the MPC model is +so I gave you one example here one model + + align:start position:0% +so I gave you one example here one model + + + align:start position:0% +so I gave you one example here one model +of inflation this is a case of that + + align:start position:0% +of inflation this is a case of that + + + align:start position:0% +of inflation this is a case of that +central banks do not like the an Anor + + align:start position:0% +central banks do not like the an Anor + + + align:start position:0% +central banks do not like the an Anor +unanchor inflation expectation that's my + + align:start position:0% +unanchor inflation expectation that's my + + + align:start position:0% +unanchor inflation expectation that's my +model of expectation then my Philips + + align:start position:0% +model of expectation then my Philips + + + align:start position:0% +model of expectation then my Philips +curve I plug this into my Philips curve + + align:start position:0% +curve I plug this into my Philips curve + + + align:start position:0% +curve I plug this into my Philips curve +and I get this relationship between the + + align:start position:0% +and I get this relationship between the + + + align:start position:0% +and I get this relationship between the +change in inflation and the output Gap + + align:start position:0% +change in inflation and the output Gap + + + align:start position:0% +change in inflation and the output Gap +and it's an increasing relationship and + + align:start position:0% +and it's an increasing relationship and + + + align:start position:0% +and it's an increasing relationship and +that's what I'm plotting here for any + + align:start position:0% +that's what I'm plotting here for any + + + align:start position:0% +that's what I'm plotting here for any +given + + align:start position:0% +given + + + align:start position:0% +given +level for any given level of YN then as + + align:start position:0% +level for any given level of YN then as + + + align:start position:0% +level for any given level of YN then as +a increase output the Philips curve the + + align:start position:0% +a increase output the Philips curve the + + + align:start position:0% +a increase output the Philips curve the +change in inflation the left hand side + + align:start position:0% +change in inflation the left hand side + + + align:start position:0% +change in inflation the left hand side +the difference between inflation expect + + align:start position:0% +the difference between inflation expect + + + align:start position:0% +the difference between inflation expect +to inflation Rises that's the reason + + align:start position:0% +to inflation Rises that's the reason + + + align:start position:0% +to inflation Rises that's the reason +this upward is sloping and the reason + + align:start position:0% +this upward is sloping and the reason + + + align:start position:0% +this upward is sloping and the reason +this Rises has to do with all the things + + align:start position:0% +this Rises has to do with all the things + + + align:start position:0% +this Rises has to do with all the things +that happen in the labor market no if an + + align:start position:0% +that happen in the labor market no if an + + + align:start position:0% +that happen in the labor market no if an +employment if output Rises meaning an + + align:start position:0% +employment if output Rises meaning an + + + align:start position:0% +employment if output Rises meaning an +employment is falling you need more + + align:start position:0% +employment is falling you need more + + + align:start position:0% +employment is falling you need more +employment to produce more output if + + align:start position:0% +employment to produce more output if + + + align:start position:0% +employment to produce more output if +that's the case it's more wage pressure + + align:start position:0% +that's the case it's more wage pressure + + + align:start position:0% +that's the case it's more wage pressure +that leads to a price pressure because + + align:start position:0% +that leads to a price pressure because + + + align:start position:0% +that leads to a price pressure because +there is a the market in between wages + + align:start position:0% +there is a the market in between wages + + + align:start position:0% +there is a the market in between wages +and prices and that's the way you get + + align:start position:0% +and prices and that's the way you get + + + align:start position:0% +and prices and that's the way you get +into inflation okay so I gave you one + + align:start position:0% +into inflation okay so I gave you one + + + align:start position:0% +into inflation okay so I gave you one +example says okay + + align:start position:0% +example says okay + + + align:start position:0% +example says okay +suppose that we have some equilibrium + + align:start position:0% +suppose that we have some equilibrium + + + align:start position:0% +suppose that we have some equilibrium +level of output this which is the result + + align:start position:0% +level of output this which is the result + + + align:start position:0% +level of output this which is the result +of this monetary policy this rate set by + + align:start position:0% +of this monetary policy this rate set by + + + align:start position:0% +of this monetary policy this rate set by +by by the central bank and and that's + + align:start position:0% +by by the central bank and and that's + + + align:start position:0% +by by the central bank and and that's +the is which is a function of you know + + align:start position:0% +the is which is a function of you know + + + align:start position:0% +the is which is a function of you know +the fiscal policy of the country how + + align:start position:0% +the fiscal policy of the country how + + + align:start position:0% +the fiscal policy of the country how +confident are consumers and all these + + align:start position:0% +confident are consumers and all these + + + align:start position:0% +confident are consumers and all these +kind of things so in quiz one we really + + align:start position:0% +kind of things so in quiz one we really + + + align:start position:0% +kind of things so in quiz one we really +worry only about this top diagram okay + + align:start position:0% +worry only about this top diagram okay + + + align:start position:0% +worry only about this top diagram okay +and all the shocks we had were shocks + + align:start position:0% +and all the shocks we had were shocks + + + align:start position:0% +and all the shocks we had were shocks +that happen in this top diagram and we + + align:start position:0% +that happen in this top diagram and we + + + align:start position:0% +that happen in this top diagram and we +and we look at what happened to Output + + align:start position:0% +and we look at what happened to Output + + + align:start position:0% +and we look at what happened to Output +to equilibrium output as a + + align:start position:0% +to equilibrium output as a + + + align:start position:0% +to equilibrium output as a +result now this hasn't changed it hasn't + + align:start position:0% +result now this hasn't changed it hasn't + + + align:start position:0% +result now this hasn't changed it hasn't +change that block is the same as it used + + align:start position:0% +change that block is the same as it used + + + align:start position:0% +change that block is the same as it used +to be the only difference that we have + + align:start position:0% +to be the only difference that we have + + + align:start position:0% +to be the only difference that we have +here is that this level of output H + + align:start position:0% +here is that this level of output H + + + align:start position:0% +here is that this level of output H +which is the equilibrium level of output + + align:start position:0% +which is the equilibrium level of output + + + align:start position:0% +which is the equilibrium level of output +at any point in time needs not be equal + + align:start position:0% +at any point in time needs not be equal + + + align:start position:0% +at any point in time needs not be equal +to potential output and if it is not + + align:start position:0% +to potential output and if it is not + + + align:start position:0% +to potential output and if it is not +equal to potential output that will lead + + align:start position:0% +equal to potential output that will lead + + + align:start position:0% +equal to potential output that will lead +to something with inflation either + + align:start position:0% +to something with inflation either + + + align:start position:0% +to something with inflation either +inflation disinflation or something of + + align:start position:0% +inflation disinflation or something of + + + align:start position:0% +inflation disinflation or something of +that kind in this particular case the + + align:start position:0% +that kind in this particular case the + + + align:start position:0% +that kind in this particular case the +equilibrium level of output which is + + align:start position:0% +equilibrium level of output which is + + + align:start position:0% +equilibrium level of output which is +still determined as we used to determine + + align:start position:0% +still determined as we used to determine + + + align:start position:0% +still determined as we used to determine +it happens to be higher than the natural + + align:start position:0% +it happens to be higher than the natural + + + align:start position:0% +it happens to be higher than the natural +rate of + + align:start position:0% +rate of + + + align:start position:0% +rate of +output and if if output is higher than + + align:start position:0% +output and if if output is higher than + + + align:start position:0% +output and if if output is higher than +the rate of output that means this is + + align:start position:0% +the rate of output that means this is + + + align:start position:0% +the rate of output that means this is +positive which means inflation is rising + + align:start position:0% +positive which means inflation is rising + + + align:start position:0% +positive which means inflation is rising +and that's exactly what we see here it + + align:start position:0% +and that's exactly what we see here it + + + align:start position:0% +and that's exactly what we see here it +means inflation is above expected + + align:start position:0% +means inflation is above expected + + + align:start position:0% +means inflation is above expected +inflation when expected inflation is + + align:start position:0% +inflation when expected inflation is + + + align:start position:0% +inflation when expected inflation is +equal to lag inflation + + align:start position:0% +equal to lag inflation + + + align:start position:0% +equal to lag inflation +then that means inflation is rising okay + + align:start position:0% +then that means inflation is rising okay + + + align:start position:0% +then that means inflation is rising okay +and that's what we have + + align:start position:0% +and that's what we have + + + align:start position:0% +and that's what we have +here so any question about that so this + + align:start position:0% +here so any question about that so this + + + align:start position:0% +here so any question about that so this +is we just what we did is kept analysis + + align:start position:0% +is we just what we did is kept analysis + + + align:start position:0% +is we just what we did is kept analysis +we used to have and now we added this + + align:start position:0% +we used to have and now we added this + + + align:start position:0% +we used to have and now we added this +diagram here at the bottom because it + + align:start position:0% +diagram here at the bottom because it + + + align:start position:0% +diagram here at the bottom because it +turns out that yes any equilibrium here + + align:start position:0% +turns out that yes any equilibrium here + + + align:start position:0% +turns out that yes any equilibrium here +if I move the inter around I'm going to + + align:start position:0% +if I move the inter around I'm going to + + + align:start position:0% +if I move the inter around I'm going to +change the equilibrium level of output + + align:start position:0% +change the equilibrium level of output + + + align:start position:0% +change the equilibrium level of output +those all those are equilibrium levels + + align:start position:0% +those all those are equilibrium levels + + + align:start position:0% +those all those are equilibrium levels +output but that doesn't mean that that + + align:start position:0% +output but that doesn't mean that that + + + align:start position:0% +output but that doesn't mean that that +they're consistent with the natural ER H + + align:start position:0% +they're consistent with the natural ER H + + + align:start position:0% +they're consistent with the natural ER H +with potential output and if it's not + + align:start position:0% +with potential output and if it's not + + + align:start position:0% +with potential output and if it's not +equal to potential output it's a valid + + align:start position:0% +equal to potential output it's a valid + + + align:start position:0% +equal to potential output it's a valid +equilibrium at any point in time but + + align:start position:0% +equilibrium at any point in time but + + + align:start position:0% +equilibrium at any point in time but +it's going to lead to issues on the + + align:start position:0% +it's going to lead to issues on the + + + align:start position:0% +it's going to lead to issues on the +inflation front that's all that the the + + align:start position:0% +inflation front that's all that the the + + + align:start position:0% +inflation front that's all that the the +second diagram here tells you that we + + align:start position:0% +second diagram here tells you that we + + + align:start position:0% +second diagram here tells you that we +get issues on the inflation front with + + align:start position:0% +get issues on the inflation front with + + + align:start position:0% +get issues on the inflation front with +any equilibrium level of output that is + + align:start position:0% +any equilibrium level of output that is + + + align:start position:0% +any equilibrium level of output that is +different from the natural rate of + + align:start position:0% +different from the natural rate of + + + align:start position:0% +different from the natural rate of +output that's what this diagram + + align:start position:0% +output that's what this diagram + + + align:start position:0% +output that's what this diagram +does so then I said well and that's what + + align:start position:0% +does so then I said well and that's what + + + align:start position:0% +does so then I said well and that's what +happen in the short run that's what it + + align:start position:0% +happen in the short run that's what it + + + align:start position:0% +happen in the short run that's what it +does so we keep doing what we used to do + + align:start position:0% +does so we keep doing what we used to do + + + align:start position:0% +does so we keep doing what we used to do +in the first seven lectures or so and uh + + align:start position:0% +in the first seven lectures or so and uh + + + align:start position:0% +in the first seven lectures or so and uh +this diagram just tells us what are the + + align:start position:0% +this diagram just tells us what are the + + + align:start position:0% +this diagram just tells us what are the +implications for inflation that's in the + + align:start position:0% +implications for inflation that's in the + + + align:start position:0% +implications for inflation that's in the +short run the medium run we said is when + + align:start position:0% +short run the medium run we said is when + + + align:start position:0% +short run the medium run we said is when +we is that process in which output + + align:start position:0% +we is that process in which output + + + align:start position:0% +we is that process in which output +converges back to the Natural rate to + + align:start position:0% +converges back to the Natural rate to + + + align:start position:0% +converges back to the Natural rate to +potential output how does that happen + + align:start position:0% +potential output how does that happen + + + align:start position:0% +potential output how does that happen +well it involves the central bank but + + align:start position:0% +well it involves the central bank but + + + align:start position:0% +well it involves the central bank but +it's not that the central bank is doing + + align:start position:0% +it's not that the central bank is doing + + + align:start position:0% +it's not that the central bank is doing +crazyy things effect Central Bank is + + align:start position:0% +crazyy things effect Central Bank is + + + align:start position:0% +crazyy things effect Central Bank is +reacting to what the economy is telling + + align:start position:0% +reacting to what the economy is telling + + + align:start position:0% +reacting to what the economy is telling +it needs to do here is a central bank + + align:start position:0% +it needs to do here is a central bank + + + align:start position:0% +it needs to do here is a central bank +that supposed had + + align:start position:0% +that supposed had + + + align:start position:0% +that supposed had +was before doing whatever change in the + + align:start position:0% +was before doing whatever change in the + + + align:start position:0% +was before doing whatever change in the +interest rate or in the deliver this + + align:start position:0% +interest rate or in the deliver this + + + align:start position:0% +interest rate or in the deliver this +equilibrium output here had an inflation + + align:start position:0% +equilibrium output here had an inflation + + + align:start position:0% +equilibrium output here had an inflation +of around 2% that was consistent with + + align:start position:0% +of around 2% that was consistent with + + + align:start position:0% +of around 2% that was consistent with +the target it had now suddenly it finds + + align:start position:0% +the target it had now suddenly it finds + + + align:start position:0% +the target it had now suddenly it finds +itself in a situation like this and + + align:start position:0% +itself in a situation like this and + + + align:start position:0% +itself in a situation like this and +inflation starts climbing okay you get + + align:start position:0% +inflation starts climbing okay you get + + + align:start position:0% +inflation starts climbing okay you get +3% one year 4% the next one 6 nine in a + + align:start position:0% +3% one year 4% the next one 6 nine in a + + + align:start position:0% +3% one year 4% the next one 6 nine in a +situation like that well it's very + + align:start position:0% +situation like that well it's very + + + align:start position:0% +situation like that well it's very +natural for that Central Bank if it's a + + align:start position:0% +natural for that Central Bank if it's a + + + align:start position:0% +natural for that Central Bank if it's a +responsible Central Bank to react to + + align:start position:0% +responsible Central Bank to react to + + + align:start position:0% +responsible Central Bank to react to +that and the only reaction a central + + align:start position:0% +that and the only reaction a central + + + align:start position:0% +that and the only reaction a central +bank can have + + align:start position:0% +bank can have + + + align:start position:0% +bank can have +the main the main reaction can have is + + align:start position:0% +the main the main reaction can have is + + + align:start position:0% +the main the main reaction can have is +to raise interest rates okay and that's + + align:start position:0% +to raise interest rates okay and that's + + + align:start position:0% +to raise interest rates okay and that's +exactly what it starts happening if the + + align:start position:0% +exactly what it starts happening if the + + + align:start position:0% +exactly what it starts happening if the +Central Bank finds itself with inflation + + align:start position:0% +Central Bank finds itself with inflation + + + align:start position:0% +Central Bank finds itself with inflation +in this Cas is that is accelerating it + + align:start position:0% +in this Cas is that is accelerating it + + + align:start position:0% +in this Cas is that is accelerating it +will start increasing interest rate and + + align:start position:0% +will start increasing interest rate and + + + align:start position:0% +will start increasing interest rate and +this process of acceleration of + + align:start position:0% +this process of acceleration of + + + align:start position:0% +this process of acceleration of +inflation in this case would only stop + + align:start position:0% +inflation in this case would only stop + + + align:start position:0% +inflation in this case would only stop +when output is equal to the Natural to + + align:start position:0% +when output is equal to the Natural to + + + align:start position:0% +when output is equal to the Natural to +potential output okay and output is + + align:start position:0% +potential output okay and output is + + + align:start position:0% +potential output okay and output is +equal we can Define implicitly what that + + align:start position:0% +equal we can Define implicitly what that + + + align:start position:0% +equal we can Define implicitly what that +interest rate is and we can call it the + + align:start position:0% +interest rate is and we can call it the + + + align:start position:0% +interest rate is and we can call it the +natural rate of interest rate sometimes + + align:start position:0% +natural rate of interest rate sometimes + + + align:start position:0% +natural rate of interest rate sometimes +we call it we sell + + align:start position:0% +we call it we sell + + + align:start position:0% +we call it we sell +interest rate of interest rate neutral + + align:start position:0% +interest rate of interest rate neutral + + + align:start position:0% +interest rate of interest rate neutral +interest rate R star lots of names for + + align:start position:0% +interest rate R star lots of names for + + + align:start position:0% +interest rate R star lots of names for +this interest rate but this interest is + + align:start position:0% +this interest rate but this interest is + + + align:start position:0% +this interest rate but this interest is +simply the one that gives us an + + align:start position:0% +simply the one that gives us an + + + align:start position:0% +simply the one that gives us an +equilibrium output in our asln diagram + + align:start position:0% +equilibrium output in our asln diagram + + + align:start position:0% +equilibrium output in our asln diagram +that is equal to potential output that's + + align:start position:0% +that is equal to potential output that's + + + align:start position:0% +that is equal to potential output that's +that's all that this RN means and here + + align:start position:0% +that's all that this RN means and here + + + align:start position:0% +that's all that this RN means and here +I'm solving it you know it's is the rate + + align:start position:0% +I'm solving it you know it's is the rate + + + align:start position:0% +I'm solving it you know it's is the rate +that implicitly gives us an equilibrium + + align:start position:0% +that implicitly gives us an equilibrium + + + align:start position:0% +that implicitly gives us an equilibrium +output here H that is equal to the + + align:start position:0% +output here H that is equal to the + + + align:start position:0% +output here H that is equal to the +Natural rate of output okay that defines + + align:start position:0% +Natural rate of output okay that defines + + + align:start position:0% +Natural rate of output okay that defines +it implicitly + + align:start position:0% +it implicitly + + + align:start position:0% +it implicitly +okay there we are is all that + + align:start position:0% +okay there we are is all that + + + align:start position:0% +okay there we are is all that +clear yes okay I think you're going to + + align:start position:0% +clear yes okay I think you're going to + + + align:start position:0% +clear yes okay I think you're going to +have a a big chunk of your current pie + + align:start position:0% +have a a big chunk of your current pie + + + align:start position:0% +have a a big chunk of your current pie +set is about this model and so on and + + align:start position:0% +set is about this model and so on and + + + align:start position:0% +set is about this model and so on and +and that's a good thing and you'll see + + align:start position:0% +and that's a good thing and you'll see + + + align:start position:0% +and that's a good thing and you'll see +it also in the next one this again I + + align:start position:0% +it also in the next one this again I + + + align:start position:0% +it also in the next one this again I +think this is important then I talk + + align:start position:0% +think this is important then I talk + + + align:start position:0% +think this is important then I talk +about the difference between anchor and + + align:start position:0% +about the difference between anchor and + + + align:start position:0% +about the difference between anchor and +an anchor expectations I said look here + + align:start position:0% +an anchor expectations I said look here + + + align:start position:0% +an anchor expectations I said look here +we have a situation that suppose we + + align:start position:0% +we have a situation that suppose we + + + align:start position:0% +we have a situation that suppose we +started at 2% and then we found ourself + + align:start position:0% +started at 2% and then we found ourself + + + align:start position:0% +started at 2% and then we found ourself +in a situation like that that means + + align:start position:0% +in a situation like that that means + + + align:start position:0% +in a situation like that that means +inflation start building up we got to 9% + + align:start position:0% +inflation start building up we got to 9% + + + align:start position:0% +inflation start building up we got to 9% +or so so now the FED gets scared and it + + align:start position:0% +or so so now the FED gets scared and it + + + align:start position:0% +or so so now the FED gets scared and it +starts raising interest rates so that's + + align:start position:0% +starts raising interest rates so that's + + + align:start position:0% +starts raising interest rates so that's +what we're moving up lower in output and + + align:start position:0% +what we're moving up lower in output and + + + align:start position:0% +what we're moving up lower in output and +as it lowers output reduces the output + + align:start position:0% +as it lowers output reduces the output + + + align:start position:0% +as it lowers output reduces the output +Gap and therefore reduces the change in + + align:start position:0% +Gap and therefore reduces the change in + + + align:start position:0% +Gap and therefore reduces the change in +inflation here but inflation keeps + + align:start position:0% +inflation here but inflation keeps + + + align:start position:0% +inflation here but inflation keeps +rising in this particular model because + + align:start position:0% +rising in this particular model because + + + align:start position:0% +rising in this particular model because +expected inflation is an anchor and I + + align:start position:0% +expected inflation is an anchor and I + + + align:start position:0% +expected inflation is an anchor and I +said well suppose that eventually the + + align:start position:0% +said well suppose that eventually the + + + align:start position:0% +said well suppose that eventually the +FED gets to that interest rate here so + + align:start position:0% +FED gets to that interest rate here so + + + align:start position:0% +FED gets to that interest rate here so +we get to situation like that and I + + align:start position:0% +we get to situation like that and I + + + align:start position:0% +we get to situation like that and I +asked the question has the FED solved + + align:start position:0% +asked the question has the FED solved + + + align:start position:0% +asked the question has the FED solved +the problem now okay finally we got to + + align:start position:0% +the problem now okay finally we got to + + + align:start position:0% +the problem now okay finally we got to +situation where the the interest rate is + + align:start position:0% +situation where the the interest rate is + + + align:start position:0% +situation where the the interest rate is +equal to an natural rate of interest + + align:start position:0% +equal to an natural rate of interest + + + align:start position:0% +equal to an natural rate of interest +rate that tells me that output is equal + + align:start position:0% +rate that tells me that output is equal + + + align:start position:0% +rate that tells me that output is equal +to potential output that tells me here + + align:start position:0% +to potential output that tells me here + + + align:start position:0% +to potential output that tells me here +that inflation is not changing problem + + align:start position:0% +that inflation is not changing problem + + + align:start position:0% +that inflation is not changing problem +is that we already had inflation of 9% + + align:start position:0% +is that we already had inflation of 9% + + + align:start position:0% +is that we already had inflation of 9% +at some point so so here inflation stops + + align:start position:0% +at some point so so here inflation stops + + + align:start position:0% +at some point so so here inflation stops +rising in this particular model with + + align:start position:0% +rising in this particular model with + + + align:start position:0% +rising in this particular model with +expected inflation an anchor expected + + align:start position:0% +expected inflation an anchor expected + + + align:start position:0% +expected inflation an anchor expected +inflation but stopping is not enough + + align:start position:0% +inflation but stopping is not enough + + + align:start position:0% +inflation but stopping is not enough +because that's gives leaves us level of + + align:start position:0% +because that's gives leaves us level of + + + align:start position:0% +because that's gives leaves us level of +inflation of + + align:start position:0% +inflation of + + + align:start position:0% +inflation of +9% that means that the FED in order to + + align:start position:0% +9% that means that the FED in order to + + + align:start position:0% +9% that means that the FED in order to +bring back inflation to 2% it needs to + + align:start position:0% +bring back inflation to 2% it needs to + + + align:start position:0% +bring back inflation to 2% it needs to +go into this region so inflation starts + + align:start position:0% +go into this region so inflation starts + + + align:start position:0% +go into this region so inflation starts +coming down from 9% 7% 6% 5% and so on + + align:start position:0% +coming down from 9% 7% 6% 5% and so on + + + align:start position:0% +coming down from 9% 7% 6% 5% and so on +okay so if you have an anchor + + align:start position:0% +okay so if you have an anchor + + + align:start position:0% +okay so if you have an anchor +expectation and and inflation overshoots + + align:start position:0% +expectation and and inflation overshoots + + + align:start position:0% +expectation and and inflation overshoots +you're going to have to cause a + + align:start position:0% +you're going to have to cause a + + + align:start position:0% +you're going to have to cause a +recession and probably a severe + + align:start position:0% +recession and probably a severe + + + align:start position:0% +recession and probably a severe +recession there's no way around that and + + align:start position:0% +recession there's no way around that and + + + align:start position:0% +recession there's no way around that and +that's what the FED has been struggling + + align:start position:0% +that's what the FED has been struggling + + + align:start position:0% +that's what the FED has been struggling +to do is is struggling not to because + + align:start position:0% +to do is is struggling not to because + + + align:start position:0% +to do is is struggling not to because +the Fed we are in a situation not only + + align:start position:0% +the Fed we are in a situation not only + + + align:start position:0% +the Fed we are in a situation not only +in the US but in the US in particular + + align:start position:0% +in the US but in the US in particular + + + align:start position:0% +in the US but in the US in particular +where inflation is way above the target + + align:start position:0% +where inflation is way above the target + + + align:start position:0% +where inflation is way above the target +level H but expected inflation has been + + align:start position:0% +level H but expected inflation has been + + + align:start position:0% +level H but expected inflation has been +more or less stable and so this when + + align:start position:0% +more or less stable and so this when + + + align:start position:0% +more or less stable and so this when +people talk about being able to restore + + align:start position:0% +people talk about being able to restore + + + align:start position:0% +people talk about being able to restore +sort of reasonable levels of inflation + + align:start position:0% +sort of reasonable levels of inflation + + + align:start position:0% +sort of reasonable levels of inflation +in a soft landed manner with a soft + + align:start position:0% +in a soft landed manner with a soft + + + align:start position:0% +in a soft landed manner with a soft +Landing that means that you don't need + + align:start position:0% +Landing that means that you don't need + + + align:start position:0% +Landing that means that you don't need +to cost a b recession to bring inflation + + align:start position:0% +to cost a b recession to bring inflation + + + align:start position:0% +to cost a b recession to bring inflation +back to 2% you just can bring it + + align:start position:0% +back to 2% you just can bring it + + + align:start position:0% +back to 2% you just can bring it +smoothly here with this model of + + align:start position:0% +smoothly here with this model of + + + align:start position:0% +smoothly here with this model of +expected inflation doesn't work but if + + align:start position:0% +expected inflation doesn't work but if + + + align:start position:0% +expected inflation doesn't work but if +expect if the Bank Central Bank has + + align:start position:0% +expect if the Bank Central Bank has + + + align:start position:0% +expect if the Bank Central Bank has +credibility H and inflation remain Anor + + align:start position:0% +credibility H and inflation remain Anor + + + align:start position:0% +credibility H and inflation remain Anor +people continue to believe that the FED + + align:start position:0% +people continue to believe that the FED + + + align:start position:0% +people continue to believe that the FED +will go back to 2% then you don't need + + align:start position:0% +will go back to 2% then you don't need + + + align:start position:0% +will go back to 2% then you don't need +to cause a big recession otherwise you + + align:start position:0% +to cause a big recession otherwise you + + + align:start position:0% +to cause a big recession otherwise you +need to invest in bringing expectations + + align:start position:0% +need to invest in bringing expectations + + + align:start position:0% +need to invest in bringing expectations +down and that the only way you can + + align:start position:0% +down and that the only way you can + + + align:start position:0% +down and that the only way you can +invest in doing that is causing a + + align:start position:0% +invest in doing that is causing a + + + align:start position:0% +invest in doing that is causing a +recession okay but that's the reason I + + align:start position:0% +recession okay but that's the reason I + + + align:start position:0% +recession okay but that's the reason I +said central banks worry so much about + + align:start position:0% +said central banks worry so much about + + + align:start position:0% +said central banks worry so much about +keeping inflation credibility because + + align:start position:0% +keeping inflation credibility because + + + align:start position:0% +keeping inflation credibility because +otherwise they need to + + align:start position:0% +otherwise they need to + + + align:start position:0% +otherwise they need to +overshoot in order to restore um long + + align:start position:0% +overshoot in order to restore um long + + + align:start position:0% +overshoot in order to restore um long +run balance + + align:start position:0% +run balance + + + align:start position:0% +run balance +okay + + align:start position:0% +okay + + + align:start position:0% +okay +good + + align:start position:0% +good + + + align:start position:0% +good +now you may Wonder well this I mean this + + align:start position:0% +now you may Wonder well this I mean this + + + align:start position:0% +now you may Wonder well this I mean this +looks pretty simple to do no just if you + + align:start position:0% +looks pretty simple to do no just if you + + + align:start position:0% +looks pretty simple to do no just if you +have a problem like this just go quickly + + align:start position:0% +have a problem like this just go quickly + + + align:start position:0% +have a problem like this just go quickly +to that point there no and then the + + align:start position:0% +to that point there no and then the + + + align:start position:0% +to that point there no and then the +problem is over you don't let inflation + + align:start position:0% +problem is over you don't let inflation + + + align:start position:0% +problem is over you don't let inflation +build to 9% or something like that you + + align:start position:0% +build to 9% or something like that you + + + align:start position:0% +build to 9% or something like that you +react immediately the problem is there's + + align:start position:0% +react immediately the problem is there's + + + align:start position:0% +react immediately the problem is there's +a f sentence that was going by Milton + + align:start position:0% +a f sentence that was going by Milton + + + align:start position:0% +a f sentence that was going by Milton +fredman is that monetary policy acts on + + align:start position:0% +fredman is that monetary policy acts on + + + align:start position:0% +fredman is that monetary policy acts on +the economy with long and variable lags + + align:start position:0% +the economy with long and variable lags + + + align:start position:0% +the economy with long and variable lags +so first of all it's very difficult at + + align:start position:0% +so first of all it's very difficult at + + + align:start position:0% +so first of all it's very difficult at +any point in time to know where is + + align:start position:0% +any point in time to know where is + + + align:start position:0% +any point in time to know where is +potential output or what is the natural + + align:start position:0% +potential output or what is the natural + + + align:start position:0% +potential output or what is the natural +rate of unemployment I mean you sort of + + align:start position:0% +rate of unemployment I mean you sort of + + + align:start position:0% +rate of unemployment I mean you sort of +sense it but the truth is that the only + + align:start position:0% +sense it but the truth is that the only + + + align:start position:0% +sense it but the truth is that the only +way you really know is is by looking at + + align:start position:0% +way you really know is is by looking at + + + align:start position:0% +way you really know is is by looking at +inflation so it's inflation that really + + align:start position:0% +inflation so it's inflation that really + + + align:start position:0% +inflation so it's inflation that really +tells you that you're one side of the + + align:start position:0% +tells you that you're one side of the + + + align:start position:0% +tells you that you're one side of the +other it's very difficult to you you + + align:start position:0% +other it's very difficult to you you + + + align:start position:0% +other it's very difficult to you you +have some historical average and so on + + align:start position:0% +have some historical average and so on + + + align:start position:0% +have some historical average and so on +but these things do move move around so + + align:start position:0% +but these things do move move around so + + + align:start position:0% +but these things do move move around so +it's difficult at any point in time to + + align:start position:0% +it's difficult at any point in time to + + + align:start position:0% +it's difficult at any point in time to +know whether you you are at our end or + + align:start position:0% +know whether you you are at our end or + + + align:start position:0% +know whether you you are at our end or +not the second thing is that here + + align:start position:0% +not the second thing is that here + + + align:start position:0% +not the second thing is that here +everything happens immediately if I move + + align:start position:0% +everything happens immediately if I move + + + align:start position:0% +everything happens immediately if I move +immediately then output immediately + + align:start position:0% +immediately then output immediately + + + align:start position:0% +immediately then output immediately +jumps here that's not the way monetary + + align:start position:0% +jumps here that's not the way monetary + + + align:start position:0% +jumps here that's not the way monetary +policy operates in practice it takes + + align:start position:0% +policy operates in practice it takes + + + align:start position:0% +policy operates in practice it takes +time for monetary policy to to to affect + + align:start position:0% +time for monetary policy to to to affect + + + align:start position:0% +time for monetary policy to to to affect +the economy and so this the situation + + align:start position:0% +the economy and so this the situation + + + align:start position:0% +the economy and so this the situation +that happened I I would say until last + + align:start position:0% +that happened I I would say until last + + + align:start position:0% +that happened I I would say until last +week was the FED knew that the inflation + + align:start position:0% +week was the FED knew that the inflation + + + align:start position:0% +week was the FED knew that the inflation +was still to too high but it but it also + + align:start position:0% +was still to too high but it but it also + + + align:start position:0% +was still to too high but it but it also +knew that it had done a lot he had hiked + + align:start position:0% +knew that it had done a lot he had hiked + + + align:start position:0% +knew that it had done a lot he had hiked +rates very aggressively by a lot and + + align:start position:0% +rates very aggressively by a lot and + + + align:start position:0% +rates very aggressively by a lot and +since there are lags between the the + + align:start position:0% +since there are lags between the the + + + align:start position:0% +since there are lags between the the +increasing interest rate and and the + + align:start position:0% +increasing interest rate and and the + + + align:start position:0% +increasing interest rate and and the +declining output the fed's concern was + + align:start position:0% +declining output the fed's concern was + + + align:start position:0% +declining output the fed's concern was +well it's clear that I still have + + align:start position:0% +well it's clear that I still have + + + align:start position:0% +well it's clear that I still have +inflation but it may well be the case + + align:start position:0% +inflation but it may well be the case + + + align:start position:0% +inflation but it may well be the case +that when this thing finally hits the + + align:start position:0% +that when this thing finally hits the + + + align:start position:0% +that when this thing finally hits the +economy it hits us too much and we end + + align:start position:0% +economy it hits us too much and we end + + + align:start position:0% +economy it hits us too much and we end +up in a recession and an unwanted + + align:start position:0% +up in a recession and an unwanted + + + align:start position:0% +up in a recession and an unwanted +recession that was a concern okay H now + + align:start position:0% +recession that was a concern okay H now + + + align:start position:0% +recession that was a concern okay H now +with what is happening right now there's + + align:start position:0% +with what is happening right now there's + + + align:start position:0% +with what is happening right now there's +a little bit of a concern that we got to + + align:start position:0% +a little bit of a concern that we got to + + + align:start position:0% +a little bit of a concern that we got to +that point because things were very slow + + align:start position:0% +that point because things were very slow + + + align:start position:0% +that point because things were very slow +for a variety of reasons but now + + align:start position:0% +for a variety of reasons but now + + + align:start position:0% +for a variety of reasons but now +something broke and the question is now + + align:start position:0% +something broke and the question is now + + + align:start position:0% +something broke and the question is now +that something has broken well will we + + align:start position:0% +that something has broken well will we + + + align:start position:0% +that something has broken well will we +sort of decelerate the economy very very + + align:start position:0% +sort of decelerate the economy very very + + + align:start position:0% +sort of decelerate the economy very very +fast and that's a concern that's what is + + align:start position:0% +fast and that's a concern that's what is + + + align:start position:0% +fast and that's a concern that's what is +happening right now okay but that's what + + align:start position:0% +happening right now okay but that's what + + + align:start position:0% +happening right now okay but that's what +makes monetary policy much more + + align:start position:0% +makes monetary policy much more + + + align:start position:0% +makes monetary policy much more +difficult than this little diagram is + + align:start position:0% +difficult than this little diagram is + + + align:start position:0% +difficult than this little diagram is +that you you have all this lags these + + align:start position:0% +that you you have all this lags these + + + align:start position:0% +that you you have all this lags these +uncertainties and all these + + align:start position:0% +uncertainties and all these + + + align:start position:0% +uncertainties and all these +nonlinearities and Sly things happen + + align:start position:0% + + + + align:start position:0% + +okay let me tell you when things can go + + align:start position:0% +okay let me tell you when things can go + + + align:start position:0% +okay let me tell you when things can go +really really wrong it's not the issue + + align:start position:0% +really really wrong it's not the issue + + + align:start position:0% +really really wrong it's not the issue +now but but we're very close to that + + align:start position:0% +now but but we're very close to that + + + align:start position:0% +now but but we're very close to that +during the global recession Japan has + + align:start position:0% +during the global recession Japan has + + + align:start position:0% +during the global recession Japan has +experienced several episodes like this + + align:start position:0% +experienced several episodes like this + + + align:start position:0% +experienced several episodes like this +which is the following suppose you have + + align:start position:0% +which is the following suppose you have + + + align:start position:0% +which is the following suppose you have +a situation where ER your inflation is + + align:start position:0% +a situation where ER your inflation is + + + align:start position:0% +a situation where ER your inflation is +low typically these things happen in + + align:start position:0% +low typically these things happen in + + + align:start position:0% +low typically these things happen in +situations where your inflation is low + + align:start position:0% +situations where your inflation is low + + + align:start position:0% +situations where your inflation is low +and for whatever reason your natural + + align:start position:0% +and for whatever reason your natural + + + align:start position:0% +and for whatever reason your natural +rate of unemployment is is + + align:start position:0% +rate of unemployment is is + + + align:start position:0% +rate of unemployment is is +negative so you have inflation close to + + align:start position:0% +negative so you have inflation close to + + + align:start position:0% +negative so you have inflation close to +zero say and then the natural rate + + align:start position:0% +zero say and then the natural rate + + + align:start position:0% +zero say and then the natural rate +of interest rate is + + align:start position:0% +of interest rate is + + + align:start position:0% +of interest rate is +negative what's the problem suppose you + + align:start position:0% +negative what's the problem suppose you + + + align:start position:0% +negative what's the problem suppose you +have a zero lower + + align:start position:0% +have a zero lower + + + align:start position:0% +have a zero lower +bound well if you have a zero lower + + align:start position:0% +bound well if you have a zero lower + + + align:start position:0% +bound well if you have a zero lower +bound means that you're not going to hit + + align:start position:0% +bound means that you're not going to hit + + + align:start position:0% +bound means that you're not going to hit +this + + align:start position:0% +this + + + align:start position:0% +this +rate the best you can do if inflation is + + align:start position:0% +rate the best you can do if inflation is + + + align:start position:0% +rate the best you can do if inflation is +around zero then you set the nominal + + align:start position:0% +around zero then you set the nominal + + + align:start position:0% +around zero then you set the nominal +interest rate to zero and then the real + + align:start position:0% +interest rate to zero and then the real + + + align:start position:0% +interest rate to zero and then the real +interest rate is around + + align:start position:0% +interest rate is around + + + align:start position:0% +interest rate is around +zero well the problem is that at zero + + align:start position:0% +zero well the problem is that at zero + + + align:start position:0% +zero well the problem is that at zero +you generate negative + + align:start position:0% +you generate negative + + + align:start position:0% +you generate negative +inflation but if you generate negative + + align:start position:0% +inflation but if you generate negative + + + align:start position:0% +inflation but if you generate negative +inflation and the nominal interest rate + + align:start position:0% +inflation and the nominal interest rate + + + align:start position:0% +inflation and the nominal interest rate +is fixed at zero then now you get a + + align:start position:0% +is fixed at zero then now you get a + + + align:start position:0% +is fixed at zero then now you get a +positive real interest rate because the + + align:start position:0% +positive real interest rate because the + + + align:start position:0% +positive real interest rate because the +real interest rate is equal to the + + align:start position:0% +real interest rate is equal to the + + + align:start position:0% +real interest rate is equal to the +nominal interest rate which is zero + + align:start position:0% +nominal interest rate which is zero + + + align:start position:0% +nominal interest rate which is zero +minus inflation expected inflation but + + align:start position:0% +minus inflation expected inflation but + + + align:start position:0% +minus inflation expected inflation but +if expected inflation or inflation is + + align:start position:0% +if expected inflation or inflation is + + + align:start position:0% +if expected inflation or inflation is +negative minus minus is positive so that + + align:start position:0% +negative minus minus is positive so that + + + align:start position:0% +negative minus minus is positive so that +means your real interest rate is + + align:start position:0% +means your real interest rate is + + + align:start position:0% +means your real interest rate is +actually positive so your really you you + + align:start position:0% +actually positive so your really you you + + + align:start position:0% +actually positive so your really you you +wanted something negative but you end up + + align:start position:0% +wanted something negative but you end up + + + align:start position:0% +wanted something negative but you end up +with something + + align:start position:0% +with something + + + align:start position:0% +with something +positive that means now you have a big + + align:start position:0% +positive that means now you have a big + + + align:start position:0% +positive that means now you have a big +gap + + align:start position:0% +gap + + + align:start position:0% +gap +here so + + align:start position:0% +here so + + + align:start position:0% +here so +inflation you get into a deflation now + + align:start position:0% +inflation you get into a deflation now + + + align:start position:0% +inflation you get into a deflation now +now inflation is very very low it gets + + align:start position:0% +now inflation is very very low it gets + + + align:start position:0% +now inflation is very very low it gets +very negative well your real as + + align:start position:0% +very negative well your real as + + + align:start position:0% +very negative well your real as +inflation gets more and more negative + + align:start position:0% +inflation gets more and more negative + + + align:start position:0% +inflation gets more and more negative +your real interest keeps climbing so you + + align:start position:0% +your real interest keeps climbing so you + + + align:start position:0% +your real interest keeps climbing so you +keep moving further and further away + + align:start position:0% +keep moving further and further away + + + align:start position:0% +keep moving further and further away +from the natural rate of interest rate + + align:start position:0% +from the natural rate of interest rate + + + align:start position:0% +from the natural rate of interest rate +that's something that is very scary for + + align:start position:0% +that's something that is very scary for + + + align:start position:0% +that's something that is very scary for +an economy is a def deflationary trap + + align:start position:0% +an economy is a def deflationary trap + + + align:start position:0% +an economy is a def deflationary trap +and that's the way you get + + align:start position:0% +and that's the way you get + + + align:start position:0% +and that's the way you get +into deep recessions in fact that's what + + align:start position:0% +into deep recessions in fact that's what + + + align:start position:0% +into deep recessions in fact that's what +happened during the Great Recession in + + align:start position:0% +happened during the Great Recession in + + + align:start position:0% +happened during the Great Recession in +the + + align:start position:0% +the + + + align:start position:0% +the +US the + + align:start position:0% +US the + + + align:start position:0% +US the +no during the Great Depression in the US + + align:start position:0% +no during the Great Depression in the US + + + align:start position:0% +no during the Great Depression in the US +okay during the Great Recession we were + + align:start position:0% +okay during the Great Recession we were + + + align:start position:0% +okay during the Great Recession we were +close to it but we didn't get quite + + align:start position:0% +close to it but we didn't get quite + + + align:start position:0% +close to it but we didn't get quite +there in in because lots of things were + + align:start position:0% +there in in because lots of things were + + + align:start position:0% +there in in because lots of things were +done to prevent a repeat of the Great + + align:start position:0% +done to prevent a repeat of the Great + + + align:start position:0% +done to prevent a repeat of the Great +Depression the one of the biggest + + align:start position:0% +Depression the one of the biggest + + + align:start position:0% +Depression the one of the biggest +problems with the Great Depression ER + + align:start position:0% +problems with the Great Depression ER + + + align:start position:0% +problems with the Great Depression ER +was that ER monetary policy was not + + align:start position:0% +was that ER monetary policy was not + + + align:start position:0% +was that ER monetary policy was not +against the zero lower bound but it was + + align:start position:0% +against the zero lower bound but it was + + + align:start position:0% +against the zero lower bound but it was +very slow to + + align:start position:0% +very slow to + + + align:start position:0% +very slow to +react okay they were in a situation like + + align:start position:0% +react okay they were in a situation like + + + align:start position:0% +react okay they were in a situation like +in this diagram + + align:start position:0% + + + + align:start position:0% + +here and and but they kept the interest + + align:start position:0% +here and and but they kept the interest + + + align:start position:0% +here and and but they kept the interest +rate high and they moveed very slowly + + align:start position:0% +rate high and they moveed very slowly + + + align:start position:0% +rate high and they moveed very slowly +and when they tried to catch up well + + align:start position:0% +and when they tried to catch up well + + + align:start position:0% +and when they tried to catch up well +they were into deflation environment so + + align:start position:0% +they were into deflation environment so + + + align:start position:0% +they were into deflation environment so +the real interet was moving away from + + align:start position:0% +the real interet was moving away from + + + align:start position:0% +the real interet was moving away from +them despite the fact that they were + + align:start position:0% +them despite the fact that they were + + + align:start position:0% +them despite the fact that they were +moving the nominal interest rate down + + align:start position:0% +moving the nominal interest rate down + + + align:start position:0% +moving the nominal interest rate down +and that you can see here so there the + + align:start position:0% +and that you can see here so there the + + + align:start position:0% +and that you can see here so there the +Great depression starts around 1929 it + + align:start position:0% +Great depression starts around 1929 it + + + align:start position:0% +Great depression starts around 1929 it +starts really in + + align:start position:0% +starts really in + + + align:start position:0% +starts really in +1929 H an employment initially was low + + align:start position:0% +1929 H an employment initially was low + + + align:start position:0% +1929 H an employment initially was low +then nominal interest rate was around 5% + + align:start position:0% +then nominal interest rate was around 5% + + + align:start position:0% +then nominal interest rate was around 5% +and inflation rate growth declined very + + align:start position:0% +and inflation rate growth declined very + + + align:start position:0% +and inflation rate growth declined very +rapidly in inflation rate was around + + align:start position:0% +rapidly in inflation rate was around + + + align:start position:0% +rapidly in inflation rate was around +zero so you had a one year the real + + align:start position:0% +zero so you had a one year the real + + + align:start position:0% +zero so you had a one year the real +interest rate was around 5% as well okay + + align:start position:0% +interest rate was around 5% as well okay + + + align:start position:0% +interest rate was around 5% as well okay +well things got worse and employment + + align:start position:0% +well things got worse and employment + + + align:start position:0% +well things got worse and employment +began to climb very rapidly and so the + + align:start position:0% +began to climb very rapidly and so the + + + align:start position:0% +began to climb very rapidly and so the +FED began to lower interest rates + + align:start position:0% +FED began to lower interest rates + + + align:start position:0% +FED began to lower interest rates +nominal interest rate you know it went + + align:start position:0% +nominal interest rate you know it went + + + align:start position:0% +nominal interest rate you know it went +from 5% to 4% those were unusually low + + align:start position:0% +from 5% to 4% those were unusually low + + + align:start position:0% +from 5% to 4% those were unusually low +interest rate for the time but the + + align:start position:0% +interest rate for the time but the + + + align:start position:0% +interest rate for the time but the +problem is that the inflation by then + + align:start position:0% +problem is that the inflation by then + + + align:start position:0% +problem is that the inflation by then +was minus 2 and a half% so the real + + align:start position:0% +was minus 2 and a half% so the real + + + align:start position:0% +was minus 2 and a half% so the real +interest rate they were lowering the + + align:start position:0% +interest rate they were lowering the + + + align:start position:0% +interest rate they were lowering the +nominal interest rate but the real + + align:start position:0% +nominal interest rate but the real + + + align:start position:0% +nominal interest rate but the real +interest rate was rising and + + align:start position:0% +interest rate was rising and + + + align:start position:0% +interest rate was rising and +unemployment accordingly was Rising as + + align:start position:0% +unemployment accordingly was Rising as + + + align:start position:0% +unemployment accordingly was Rising as +well it kept going no look see then they + + align:start position:0% +well it kept going no look see then they + + + align:start position:0% +well it kept going no look see then they +began to cut the interest rate more + + align:start position:0% +began to cut the interest rate more + + + align:start position:0% +began to cut the interest rate more +aggressively okay but but we got into + + align:start position:0% +aggressively okay but but we got into + + + align:start position:0% +aggressively okay but but we got into +real deflation minus 10% or so so the + + align:start position:0% +real deflation minus 10% or so so the + + + align:start position:0% +real deflation minus 10% or so so the +real interest rate kept + + align:start position:0% +real interest rate kept + + + align:start position:0% +real interest rate kept +climbing at that point was a very poor + + align:start position:0% +climbing at that point was a very poor + + + align:start position:0% +climbing at that point was a very poor +Le time interest rate hike was a + + align:start position:0% +Le time interest rate hike was a + + + align:start position:0% +Le time interest rate hike was a +disaster for unemployment and because it + + align:start position:0% +disaster for unemployment and because it + + + align:start position:0% +disaster for unemployment and because it +really hied the interest rate real + + align:start position:0% +really hied the interest rate real + + + align:start position:0% +really hied the interest rate real +interest rate even more and eventually + + align:start position:0% +interest rate even more and eventually + + + align:start position:0% +interest rate even more and eventually +got got out of it with a bunch of + + align:start position:0% +got got out of it with a bunch of + + + align:start position:0% +got got out of it with a bunch of +policies that were non monetary policies + + align:start position:0% +policies that were non monetary policies + + + align:start position:0% +policies that were non monetary policies +but but + + align:start position:0% +but but + + + align:start position:0% +but but +um but that's that's what happened so so + + align:start position:0% +um but that's that's what happened so so + + + align:start position:0% +um but that's that's what happened so so +the Great Depression was very much a + + align:start position:0% +the Great Depression was very much a + + + align:start position:0% +the Great Depression was very much a +story of this + + align:start position:0% +story of this + + + align:start position:0% +story of this +kind in which essentially we get we fall + + align:start position:0% +kind in which essentially we get we fall + + + align:start position:0% +kind in which essentially we get we fall +fell into depression so that interest + + align:start position:0% +fell into depression so that interest + + + align:start position:0% +fell into depression so that interest +rate when began to climb and got the + + align:start position:0% +rate when began to climb and got the + + + align:start position:0% +rate when began to climb and got the +economy deeper and deeper into recession + + align:start position:0% +economy deeper and deeper into recession + + + align:start position:0% +economy deeper and deeper into recession +and employment Higher and Higher and so + + align:start position:0% +and employment Higher and Higher and so + + + align:start position:0% +and employment Higher and Higher and so +on and at some point monetary policy + + align:start position:0% +on and at some point monetary policy + + + align:start position:0% +on and at some point monetary policy +just didn't work so that's the reason + + align:start position:0% +just didn't work so that's the reason + + + align:start position:0% +just didn't work so that's the reason +you have essentially do massive fiscal + + align:start position:0% +you have essentially do massive fiscal + + + align:start position:0% +you have essentially do massive fiscal +policy to get out of + + align:start position:0% + + + + align:start position:0% + +it let's let me talk about some of the + + align:start position:0% +it let's let me talk about some of the + + + align:start position:0% +it let's let me talk about some of the +shocks we have discussed in the context + + align:start position:0% +shocks we have discussed in the context + + + align:start position:0% +shocks we have discussed in the context +of this more complete model now ER and + + align:start position:0% +of this more complete model now ER and + + + align:start position:0% +of this more complete model now ER and +and actually okay let me go let me talk + + align:start position:0% +and actually okay let me go let me talk + + + align:start position:0% +and actually okay let me go let me talk +about sort of two canonical type shocks + + align:start position:0% +about sort of two canonical type shocks + + + align:start position:0% +about sort of two canonical type shocks +you can have two broad type of shocks or + + align:start position:0% +you can have two broad type of shocks or + + + align:start position:0% +you can have two broad type of shocks or +or policies in in this + + align:start position:0% +or policies in in this + + + align:start position:0% +or policies in in this +Ms that you want to + + align:start position:0% +Ms that you want to + + + align:start position:0% +Ms that you want to +analyze some of them are aggregate + + align:start position:0% +analyze some of them are aggregate + + + align:start position:0% +analyze some of them are aggregate +demand either policies or shocks + + align:start position:0% +demand either policies or shocks + + + align:start position:0% +demand either policies or shocks +whatever those are things that you know + + align:start position:0% +whatever those are things that you know + + + align:start position:0% +whatever those are things that you know +aggregate demand policies move the is + + align:start position:0% +aggregate demand policies move the is + + + align:start position:0% +aggregate demand policies move the is +curve okay the is and the LM but moves + + align:start position:0% +curve okay the is and the LM but moves + + + align:start position:0% +curve okay the is and the LM but moves +operates in the in the in the in the + + align:start position:0% +operates in the in the in the in the + + + align:start position:0% +operates in the in the in the in the +Goods Market so this is one case of a + + align:start position:0% +Goods Market so this is one case of a + + + align:start position:0% +Goods Market so this is one case of a +contractionary f policy no a fiscal + + align:start position:0% +contractionary f policy no a fiscal + + + align:start position:0% +contractionary f policy no a fiscal +consolidation so what happens here + + align:start position:0% +consolidation so what happens here + + + align:start position:0% +consolidation so what happens here +suppose you start an equilibrium level + + align:start position:0% +suppose you start an equilibrium level + + + align:start position:0% +suppose you start an equilibrium level +of output H equal to Natural rate of + + align:start position:0% +of output H equal to Natural rate of + + + align:start position:0% +of output H equal to Natural rate of +output but now for whatever reason we're + + align:start position:0% +output but now for whatever reason we're + + + align:start position:0% +output but now for whatever reason we're +running deficits that are very large you + + align:start position:0% +running deficits that are very large you + + + align:start position:0% +running deficits that are very large you +want to reduce the size of the deficit + + align:start position:0% +want to reduce the size of the deficit + + + align:start position:0% +want to reduce the size of the deficit +well you move the is to the left no you + + align:start position:0% +well you move the is to the left no you + + + align:start position:0% +well you move the is to the left no you +cut government expenditure you increase + + align:start position:0% +cut government expenditure you increase + + + align:start position:0% +cut government expenditure you increase +taxes that will bring output below the + + align:start position:0% +taxes that will bring output below the + + + align:start position:0% +taxes that will bring output below the +natural rate of output you go to the + + align:start position:0% +natural rate of output you go to the + + + align:start position:0% +natural rate of output you go to the +Philips curve here that means inflation + + align:start position:0% +Philips curve here that means inflation + + + align:start position:0% +Philips curve here that means inflation +now you you get into deflationary forces + + align:start position:0% +now you you get into deflationary forces + + + align:start position:0% +now you you get into deflationary forces +or inflation starts declining the result + + align:start position:0% +or inflation starts declining the result + + + align:start position:0% +or inflation starts declining the result +of that so in the short run you get + + align:start position:0% +of that so in the short run you get + + + align:start position:0% +of that so in the short run you get +exactly what we had in lecture five six + + align:start position:0% +exactly what we had in lecture five six + + + align:start position:0% +exactly what we had in lecture five six +or whatever know you get a contraction + + align:start position:0% +or whatever know you get a contraction + + + align:start position:0% +or whatever know you get a contraction +in real output but on top of that you + + align:start position:0% +in real output but on top of that you + + + align:start position:0% +in real output but on top of that you +start getting inflation coming down or + + align:start position:0% +start getting inflation coming down or + + + align:start position:0% +start getting inflation coming down or +even going negative and as a result of + + align:start position:0% +even going negative and as a result of + + + align:start position:0% +even going negative and as a result of +that the central bank will react and it + + align:start position:0% +that the central bank will react and it + + + align:start position:0% +that the central bank will react and it +will react and that reaction will stop + + align:start position:0% +will react and that reaction will stop + + + align:start position:0% +will react and that reaction will stop +when in the long run well when output + + align:start position:0% +when in the long run well when output + + + align:start position:0% +when in the long run well when output +goes back to the initial level of output + + align:start position:0% +goes back to the initial level of output + + + align:start position:0% +goes back to the initial level of output +it's natural rate of output okay so the + + align:start position:0% +it's natural rate of output okay so the + + + align:start position:0% +it's natural rate of output okay so the +point of this picture that is new + + align:start position:0% +point of this picture that is new + + + align:start position:0% +point of this picture that is new +relative to things you already knew + + align:start position:0% +relative to things you already knew + + + align:start position:0% +relative to things you already knew +is that in the short run you get very + + align:start position:0% +is that in the short run you get very + + + align:start position:0% +is that in the short run you get very +much the type of responses we had + + align:start position:0% +much the type of responses we had + + + align:start position:0% +much the type of responses we had +earlier on in the medium run that is + + align:start position:0% +earlier on in the medium run that is + + + align:start position:0% +earlier on in the medium run that is +when now in the medium run you don't get + + align:start position:0% +when now in the medium run you don't get + + + align:start position:0% +when now in the medium run you don't get +that a fiscal consolation does not + + align:start position:0% +that a fiscal consolation does not + + + align:start position:0% +that a fiscal consolation does not +reduce output in the medium Run Okay a + + align:start position:0% +reduce output in the medium Run Okay a + + + align:start position:0% +reduce output in the medium Run Okay a +fiscal consolation what does is reduces + + align:start position:0% +fiscal consolation what does is reduces + + + align:start position:0% +fiscal consolation what does is reduces +the real interest rate in the in the in + + align:start position:0% +the real interest rate in the in the in + + + align:start position:0% +the real interest rate in the in the in +the long in the medium run okay so you + + align:start position:0% +the long in the medium run okay so you + + + align:start position:0% +the long in the medium run okay so you +see here output eventually goes back to + + align:start position:0% +see here output eventually goes back to + + + align:start position:0% +see here output eventually goes back to +that level with a much lower real + + align:start position:0% +that level with a much lower real + + + align:start position:0% +that level with a much lower real +interest rate and and + + align:start position:0% +interest rate and and + + + align:start position:0% +interest rate and and +U the the point is sometimes this this + + align:start position:0% +U the the point is sometimes this this + + + align:start position:0% +U the the point is sometimes this this +path this path that takes you output + + align:start position:0% +path this path that takes you output + + + align:start position:0% +path this path that takes you output +down initially and then comes back can + + align:start position:0% +down initially and then comes back can + + + align:start position:0% +down initially and then comes back can +be very painful it can take a long time + + align:start position:0% +be very painful it can take a long time + + + align:start position:0% +be very painful it can take a long time +generate a recession and so on and + + align:start position:0% +generate a recession and so on and + + + align:start position:0% +generate a recession and so on and +sometimes it can happen in easier + + align:start position:0% +sometimes it can happen in easier + + + align:start position:0% +sometimes it can happen in easier +conditions and be faster and so on many + + align:start position:0% +conditions and be faster and so on many + + + align:start position:0% +conditions and be faster and so on many +of the policies agreements that people + + align:start position:0% +of the policies agreements that people + + + align:start position:0% +of the policies agreements that people +have people that understand what they're + + align:start position:0% +have people that understand what they're + + + align:start position:0% +have people that understand what they're +talking about had to do with the speed + + align:start position:0% +talking about had to do with the speed + + + align:start position:0% +talking about had to do with the speed +at which these things happen so + + align:start position:0% +at which these things happen so + + + align:start position:0% +at which these things happen so +sometimes you know people can agree that + + align:start position:0% +sometimes you know people can agree that + + + align:start position:0% +sometimes you know people can agree that +you need a fiscal consolidation but + + align:start position:0% +you need a fiscal consolidation but + + + align:start position:0% +you need a fiscal consolidation but +someone think no this stuff is going to + + align:start position:0% +someone think no this stuff is going to + + + align:start position:0% +someone think no this stuff is going to +be very slow and so I don't want to + + align:start position:0% +be very slow and so I don't want to + + + align:start position:0% +be very slow and so I don't want to +incur in a very deep recession for very + + align:start position:0% +incur in a very deep recession for very + + + align:start position:0% +incur in a very deep recession for very +long just to adjust a little bit the + + align:start position:0% +long just to adjust a little bit the + + + align:start position:0% +long just to adjust a little bit the +fiscal deficit and others may think the + + align:start position:0% +fiscal deficit and others may think the + + + align:start position:0% +fiscal deficit and others may think the +opposite okay it's it's mostly about the + + align:start position:0% +opposite okay it's it's mostly about the + + + align:start position:0% +opposite okay it's it's mostly about the +speed but shorter response to a fiscal + + align:start position:0% +speed but shorter response to a fiscal + + + align:start position:0% +speed but shorter response to a fiscal +consolidation or to any aggregate demand + + align:start position:0% +consolidation or to any aggregate demand + + + align:start position:0% +consolidation or to any aggregate demand +contraction is different than the medium + + align:start position:0% +contraction is different than the medium + + + align:start position:0% +contraction is different than the medium +ter + + align:start position:0% + + + + align:start position:0% + +response and again the signals for the + + align:start position:0% +response and again the signals for the + + + align:start position:0% +response and again the signals for the +central bank that it needs to move + + align:start position:0% +central bank that it needs to move + + + align:start position:0% +central bank that it needs to move +interest rate they all come from this + + align:start position:0% +interest rate they all come from this + + + align:start position:0% +interest rate they all come from this +block here inflation falling that tells + + align:start position:0% +block here inflation falling that tells + + + align:start position:0% +block here inflation falling that tells +the Central Bank oops we may have a + + align:start position:0% +the Central Bank oops we may have a + + + align:start position:0% +the Central Bank oops we may have a +problem and so on another kind of shock + + align:start position:0% +problem and so on another kind of shock + + + align:start position:0% +problem and so on another kind of shock +that is is is is is more complicated and + + align:start position:0% +that is is is is is more complicated and + + + align:start position:0% +that is is is is is more complicated and +that has played a role actually very + + align:start position:0% +that has played a role actually very + + + align:start position:0% +that has played a role actually very +much in the recovery from covid is some + + align:start position:0% +much in the recovery from covid is some + + + align:start position:0% +much in the recovery from covid is some +sort of supply side shock for example an + + align:start position:0% +sort of supply side shock for example an + + + align:start position:0% +sort of supply side shock for example an +oil shock okay price of energy goes up + + align:start position:0% +oil shock okay price of energy goes up + + + align:start position:0% +oil shock okay price of energy goes up +or something like that well that one how + + align:start position:0% +or something like that well that one how + + + align:start position:0% +or something like that well that one how +do you analyze that the a supply size + + align:start position:0% +do you analyze that the a supply size + + + align:start position:0% +do you analyze that the a supply size +shock is not something that comes from + + align:start position:0% +shock is not something that comes from + + + align:start position:0% +shock is not something that comes from +the that we go to the slm part of the + + align:start position:0% +the that we go to the slm part of the + + + align:start position:0% +the that we go to the slm part of the +mall a supply size shock remember we + + align:start position:0% +mall a supply size shock remember we + + + align:start position:0% +mall a supply size shock remember we +analyze it when we did analyze the + + align:start position:0% +analyze it when we did analyze the + + + align:start position:0% +analyze it when we did analyze the +natural rate of natural rate of + + align:start position:0% +natural rate of natural rate of + + + align:start position:0% +natural rate of natural rate of +unemployment it's something that affects + + align:start position:0% +unemployment it's something that affects + + + align:start position:0% +unemployment it's something that affects +the supply side of the economy we can + + align:start position:0% +the supply side of the economy we can + + + align:start position:0% +the supply side of the economy we can +model that as an increase in the markup + + align:start position:0% +model that as an increase in the markup + + + align:start position:0% +model that as an increase in the markup +and we know that an increase in the + + align:start position:0% +and we know that an increase in the + + + align:start position:0% +and we know that an increase in the +markup will increase the natural rate of + + align:start position:0% +markup will increase the natural rate of + + + align:start position:0% +markup will increase the natural rate of +unemployment that means that that that + + align:start position:0% +unemployment that means that that that + + + align:start position:0% +unemployment that means that that that +this shock will do what to potential + + align:start position:0% + + + + align:start position:0% + +output so an energy shock especially if + + align:start position:0% +output so an energy shock especially if + + + align:start position:0% +output so an energy shock especially if +it's a persist one will operate like a + + align:start position:0% +it's a persist one will operate like a + + + align:start position:0% +it's a persist one will operate like a +markup shock and that we know will + + align:start position:0% +markup shock and that we know will + + + align:start position:0% +markup shock and that we know will +increase the natural rate of + + align:start position:0% +increase the natural rate of + + + align:start position:0% +increase the natural rate of +unemployment so what happens to the to + + align:start position:0% +unemployment so what happens to the to + + + align:start position:0% +unemployment so what happens to the to +potential + + align:start position:0% +potential + + + align:start position:0% +potential +output goes down of course it's it's + + align:start position:0% +output goes down of course it's it's + + + align:start position:0% +output goes down of course it's it's +know output is equal to employment to + + align:start position:0% +know output is equal to employment to + + + align:start position:0% +know output is equal to employment to +labor force times 1 minus the natural + + align:start position:0% +labor force times 1 minus the natural + + + align:start position:0% +labor force times 1 minus the natural +rate of unemployment if the natural rate + + align:start position:0% +rate of unemployment if the natural rate + + + align:start position:0% +rate of unemployment if the natural rate +of unemployment goes up then the + + align:start position:0% +of unemployment goes up then the + + + align:start position:0% +of unemployment goes up then the +potential output goes down so that is + + align:start position:0% +potential output goes down so that is + + + align:start position:0% +potential output goes down so that is +not a shift in the top diagram it's a + + align:start position:0% +not a shift in the top diagram it's a + + + align:start position:0% +not a shift in the top diagram it's a +shift in the lower diagram it says we + + align:start position:0% +shift in the lower diagram it says we + + + align:start position:0% +shift in the lower diagram it says we +used to have this Philips curve and now + + align:start position:0% +used to have this Philips curve and now + + + align:start position:0% +used to have this Philips curve and now +the Philips curve has shifted to the + + align:start position:0% +the Philips curve has shifted to the + + + align:start position:0% +the Philips curve has shifted to the +left because we have a new natural rate + + align:start position:0% +left because we have a new natural rate + + + align:start position:0% +left because we have a new natural rate +of an output and remember the natural + + align:start position:0% +of an output and remember the natural + + + align:start position:0% +of an output and remember the natural +rate of output is that point when a ER + + align:start position:0% +rate of output is that point when a ER + + + align:start position:0% +rate of output is that point when a ER +output equal to the Natural rate of + + align:start position:0% +output equal to the Natural rate of + + + align:start position:0% +output equal to the Natural rate of +output doesn't produce inflationary + + align:start position:0% +output doesn't produce inflationary + + + align:start position:0% +output doesn't produce inflationary +forces okay so what happened with this + + align:start position:0% +forces okay so what happened with this + + + align:start position:0% +forces okay so what happened with this +shock here so suppose the economy was in + + align:start position:0% +shock here so suppose the economy was in + + + align:start position:0% +shock here so suppose the economy was in +this equilibrium here and now it gets + + align:start position:0% +this equilibrium here and now it gets + + + align:start position:0% +this equilibrium here and now it gets +hit by an oil shock + + align:start position:0% +hit by an oil shock + + + align:start position:0% +hit by an oil shock +in the short run if no one reacts + + align:start position:0% +in the short run if no one reacts + + + align:start position:0% +in the short run if no one reacts +nothing happens to Output doesn't move + + align:start position:0% +nothing happens to Output doesn't move + + + align:start position:0% +nothing happens to Output doesn't move +much but what + + align:start position:0% + + + + align:start position:0% + +happens you see if I don't move + + align:start position:0% +happens you see if I don't move + + + align:start position:0% +happens you see if I don't move +something in this part of the diagram + + align:start position:0% +something in this part of the diagram + + + align:start position:0% +something in this part of the diagram +and not move equilibrium output in the + + align:start position:0% +and not move equilibrium output in the + + + align:start position:0% +and not move equilibrium output in the +short run equilibrium output is + + align:start position:0% +short run equilibrium output is + + + align:start position:0% +short run equilibrium output is +determined exactly in the same way we + + align:start position:0% +determined exactly in the same way we + + + align:start position:0% +determined exactly in the same way we +have determined up to now so if we get a + + align:start position:0% +have determined up to now so if we get a + + + align:start position:0% +have determined up to now so if we get a +markup shock nothing happens to Output + + align:start position:0% +markup shock nothing happens to Output + + + align:start position:0% +markup shock nothing happens to Output +if no no one no if no moves nothing + + align:start position:0% +if no no one no if no moves nothing + + + align:start position:0% +if no no one no if no moves nothing +happens to help in the short but what + + align:start position:0% + + + + align:start position:0% + +happens that we may not like yeah + + align:start position:0% +happens that we may not like yeah + + + align:start position:0% +happens that we may not like yeah +exactly what happen is the the Philips + + align:start position:0% +exactly what happen is the the Philips + + + align:start position:0% +exactly what happen is the the Philips +curve went up before that level of + + align:start position:0% +curve went up before that level of + + + align:start position:0% +curve went up before that level of +output was consistent with no changes in + + align:start position:0% +output was consistent with no changes in + + + align:start position:0% +output was consistent with no changes in +inflation now it's not we get an + + align:start position:0% +inflation now it's not we get an + + + align:start position:0% +inflation now it's not we get an +increase in inflation so the first place + + align:start position:0% +increase in inflation so the first place + + + align:start position:0% +increase in inflation so the first place +where you'll see a the effect of the of + + align:start position:0% +where you'll see a the effect of the of + + + align:start position:0% +where you'll see a the effect of the of +of of the oil shock here is inflation + + align:start position:0% +of of the oil shock here is inflation + + + align:start position:0% +of of the oil shock here is inflation +will pick up remember the price of + + align:start position:0% +will pick up remember the price of + + + align:start position:0% +will pick up remember the price of +gasoline going up and all those things + + align:start position:0% +gasoline going up and all those things + + + align:start position:0% +gasoline going up and all those things +well that's where you see it first + + align:start position:0% +well that's where you see it first + + + align:start position:0% +well that's where you see it first +before activity Falls you see it there + + align:start position:0% +before activity Falls you see it there + + + align:start position:0% +before activity Falls you see it there +that's what mess up the Philips curve + + align:start position:0% +that's what mess up the Philips curve + + + align:start position:0% +that's what mess up the Philips curve +also in the 70s and 80s we going to see + + align:start position:0% +also in the 70s and 80s we going to see + + + align:start position:0% +also in the 70s and 80s we going to see +lots of shocks of this kind initially + + align:start position:0% +lots of shocks of this kind initially + + + align:start position:0% +lots of shocks of this kind initially +unemployment didn't move M much but + + align:start position:0% +unemployment didn't move M much but + + + align:start position:0% +unemployment didn't move M much but +inflation keeps + + align:start position:0% +inflation keeps + + + align:start position:0% +inflation keeps +climbing so that's what happens well + + align:start position:0% +climbing so that's what happens well + + + align:start position:0% +climbing so that's what happens well +obviously when that happens if it's + + align:start position:0% +obviously when that happens if it's + + + align:start position:0% +obviously when that happens if it's +persistent typically central banks if + + align:start position:0% +persistent typically central banks if + + + align:start position:0% +persistent typically central banks if +they think it's very short live they're + + align:start position:0% +they think it's very short live they're + + + align:start position:0% +they think it's very short live they're +not going to react to this stuff but if + + align:start position:0% +not going to react to this stuff but if + + + align:start position:0% +not going to react to this stuff but if +if it is persistent and they think it's + + align:start position:0% +if it is persistent and they think it's + + + align:start position:0% +if it is persistent and they think it's +persistent then the reaction is what + + align:start position:0% +persistent then the reaction is what + + + align:start position:0% +persistent then the reaction is what +well they need to this only means that + + align:start position:0% +well they need to this only means that + + + align:start position:0% +well they need to this only means that +the natural rate of + + align:start position:0% +the natural rate of + + + align:start position:0% +the natural rate of +an the the natural rate of interest has + + align:start position:0% +an the the natural rate of interest has + + + align:start position:0% +an the the natural rate of interest has +gone up no because I need to for that + + align:start position:0% +gone up no because I need to for that + + + align:start position:0% +gone up no because I need to for that +same is I need to bring down equilibrium + + align:start position:0% +same is I need to bring down equilibrium + + + align:start position:0% +same is I need to bring down equilibrium +output that means I need a higher + + align:start position:0% +output that means I need a higher + + + align:start position:0% +output that means I need a higher +natural rate of interest rate or a + + align:start position:0% +natural rate of interest rate or a + + + align:start position:0% +natural rate of interest rate or a +higher rst star so what the FED needs to + + align:start position:0% +higher rst star so what the FED needs to + + + align:start position:0% +higher rst star so what the FED needs to +do the Central Bank needs to do is just + + align:start position:0% +do the Central Bank needs to do is just + + + align:start position:0% +do the Central Bank needs to do is just +start increasing interest rate that's an + + align:start position:0% +start increasing interest rate that's an + + + align:start position:0% +start increasing interest rate that's an +natural + + align:start position:0% +natural + + + align:start position:0% +natural +response a lot of what happened during + + align:start position:0% +response a lot of what happened during + + + align:start position:0% +response a lot of what happened during +the covid why inflation pick up so much + + align:start position:0% +the covid why inflation pick up so much + + + align:start position:0% +the covid why inflation pick up so much +much in in Co is because we had a shock + + align:start position:0% +much in in Co is because we had a shock + + + align:start position:0% +much in in Co is because we had a shock +of this kind it was not energy the + + align:start position:0% +of this kind it was not energy the + + + align:start position:0% +of this kind it was not energy the +energy shock came later but it was + + align:start position:0% +energy shock came later but it was + + + align:start position:0% +energy shock came later but it was +supply side transport transport cost and + + align:start position:0% +supply side transport transport cost and + + + align:start position:0% +supply side transport transport cost and +stuff like that the network the + + align:start position:0% +stuff like that the network the + + + align:start position:0% +stuff like that the network the +production Network and things like that + + align:start position:0% +production Network and things like that + + + align:start position:0% +production Network and things like that +that broke down but they thought it was + + align:start position:0% +that broke down but they thought it was + + + align:start position:0% +that broke down but they thought it was +going to be very temporary so + + align:start position:0% +going to be very temporary so + + + align:start position:0% +going to be very temporary so +understanding this model they thought + + align:start position:0% +understanding this model they thought + + + align:start position:0% +understanding this model they thought +okay look this this Curve will come back + + align:start position:0% +okay look this this Curve will come back + + + align:start position:0% +okay look this this Curve will come back +come back that but by itself so better + + align:start position:0% +come back that but by itself so better + + + align:start position:0% +come back that but by itself so better +not react right now why cause a + + align:start position:0% +not react right now why cause a + + + align:start position:0% +not react right now why cause a +recession if really this Curve will come + + align:start position:0% +recession if really this Curve will come + + + align:start position:0% +recession if really this Curve will come +down back down by itself well the + + align:start position:0% +down back down by itself well the + + + align:start position:0% +down back down by itself well the +problem is that it didn't come back by + + align:start position:0% +problem is that it didn't come back by + + + align:start position:0% +problem is that it didn't come back by +itself that fast some things came up + + align:start position:0% +itself that fast some things came up + + + align:start position:0% +itself that fast some things came up +fairly fast some others did not in + + align:start position:0% +fairly fast some others did not in + + + align:start position:0% +fairly fast some others did not in +particular labor for participation did + + align:start position:0% +particular labor for participation did + + + align:start position:0% +particular labor for participation did +not come sufficiently fast back and so + + align:start position:0% +not come sufficiently fast back and so + + + align:start position:0% +not come sufficiently fast back and so +that's the reason we stay too long in a + + align:start position:0% +that's the reason we stay too long in a + + + align:start position:0% +that's the reason we stay too long in a +situation like this and that's one of + + align:start position:0% +situation like this and that's one of + + + align:start position:0% +situation like this and that's one of +the main reasons inflation sort of creep + + align:start position:0% +the main reasons inflation sort of creep + + + align:start position:0% +the main reasons inflation sort of creep +up in in the US and also in other places + + align:start position:0% +up in in the US and also in other places + + + align:start position:0% +up in in the US and also in other places +in the world in Europe the big reason + + align:start position:0% +in the world in Europe the big reason + + + align:start position:0% +in the world in Europe the big reason +for for why inflation picked up there is + + align:start position:0% +for for why inflation picked up there is + + + align:start position:0% +for for why inflation picked up there is +because this curve move a lot up why is + + align:start position:0% + + + + align:start position:0% + +that exactly you know they had a massive + + align:start position:0% +that exactly you know they had a massive + + + align:start position:0% +that exactly you know they had a massive +energy shock and so that moved that + + align:start position:0% +energy shock and so that moved that + + + align:start position:0% +energy shock and so that moved that +curve up a + + align:start position:0% +curve up a + + + align:start position:0% +curve up a +lot + + align:start position:0% +lot + + + align:start position:0% +lot +good let's I want to now return to what + + align:start position:0% +good let's I want to now return to what + + + align:start position:0% +good let's I want to now return to what +is going on right + + align:start position:0% +is going on right + + + align:start position:0% +is going on right +now ER oh actually first I'm going to + + align:start position:0% +now ER oh actually first I'm going to + + + align:start position:0% +now ER oh actually first I'm going to +yeah right now meaning the last few days + + align:start position:0% +yeah right now meaning the last few days + + + align:start position:0% +yeah right now meaning the last few days +so it turns out that this diagram that + + align:start position:0% +so it turns out that this diagram that + + + align:start position:0% +so it turns out that this diagram that +that I use for the fiscal consolidation + + align:start position:0% +that I use for the fiscal consolidation + + + align:start position:0% +that I use for the fiscal consolidation +shock can also be used to understand a + + align:start position:0% +shock can also be used to understand a + + + align:start position:0% +shock can also be used to understand a +little bit what happens with + + align:start position:0% +little bit what happens with + + + align:start position:0% +little bit what happens with +the um Silicon Valley Bank event okay + + align:start position:0% +the um Silicon Valley Bank event okay + + + align:start position:0% +the um Silicon Valley Bank event okay +remember we model that as a credit shock + + align:start position:0% +remember we model that as a credit shock + + + align:start position:0% +remember we model that as a credit shock +we say like like that X we had it's like + + align:start position:0% +we say like like that X we had it's like + + + align:start position:0% +we say like like that X we had it's like +X going up well X going up that's + + align:start position:0% +X going up well X going up that's + + + align:start position:0% +X going up well X going up that's +exactly that it moves the yes to the + + align:start position:0% +exactly that it moves the yes to the + + + align:start position:0% +exactly that it moves the yes to the +left so a shock to + + align:start position:0% +left so a shock to + + + align:start position:0% +left so a shock to +X to to the a panic of the kind that we + + align:start position:0% +X to to the a panic of the kind that we + + + align:start position:0% +X to to the a panic of the kind that we +saw is like that it moves the to the + + align:start position:0% +saw is like that it moves the to the + + + align:start position:0% +saw is like that it moves the to the +left why is + + align:start position:0% +left why is + + + align:start position:0% +left why is +that so for any given level of the safe + + align:start position:0% +that so for any given level of the safe + + + align:start position:0% +that so for any given level of the safe +real interest rate a panic a shock to + + align:start position:0% +real interest rate a panic a shock to + + + align:start position:0% +real interest rate a panic a shock to +credit and so on moves the a to the left + + align:start position:0% +credit and so on moves the a to the left + + + align:start position:0% +credit and so on moves the a to the left +why is + + align:start position:0% + + + + align:start position:0% + +that exactly so so the real the safe + + align:start position:0% +that exactly so so the real the safe + + + align:start position:0% +that exactly so so the real the safe +interest rate doesn't go up but but but + + align:start position:0% +interest rate doesn't go up but but but + + + align:start position:0% +interest rate doesn't go up but but but +what goes up is is is the cost of + + align:start position:0% +what goes up is is is the cost of + + + align:start position:0% +what goes up is is is the cost of +borrowing because you know firms need to + + align:start position:0% +borrowing because you know firms need to + + + align:start position:0% +borrowing because you know firms need to +pay this this extra risk premium and and + + align:start position:0% +pay this this extra risk premium and and + + + align:start position:0% +pay this this extra risk premium and and +then for any given safe interest rate + + align:start position:0% +then for any given safe interest rate + + + align:start position:0% +then for any given safe interest rate +real interest rate firms have to pay + + align:start position:0% +real interest rate firms have to pay + + + align:start position:0% +real interest rate firms have to pay +more which means there is less + + align:start position:0% +more which means there is less + + + align:start position:0% +more which means there is less +investment for any given level of the + + align:start position:0% +investment for any given level of the + + + align:start position:0% +investment for any given level of the +real interest rate and so the is moves + + align:start position:0% +real interest rate and so the is moves + + + align:start position:0% +real interest rate and so the is moves +to the left and if that happens then you + + align:start position:0% +to the left and if that happens then you + + + align:start position:0% +to the left and if that happens then you +start getting deflationary + + align:start position:0% +start getting deflationary + + + align:start position:0% +start getting deflationary +forces okay so again all this happens + + align:start position:0% +forces okay so again all this happens + + + align:start position:0% +forces okay so again all this happens +very quickly here in reality I told you + + align:start position:0% +very quickly here in reality I told you + + + align:start position:0% +very quickly here in reality I told you +there are lots of lags and so on but + + align:start position:0% +there are lots of lags and so on but + + + align:start position:0% +there are lots of lags and so on but +markets begin to anticipate what will + + align:start position:0% +markets begin to anticipate what will + + + align:start position:0% +markets begin to anticipate what will +happen and + + align:start position:0% +happen and + + + align:start position:0% +happen and +so so markets begin to anticipate so so + + align:start position:0% +so so markets begin to anticipate so so + + + align:start position:0% +so so markets begin to anticipate so so +in the in the immediate output doesn't + + align:start position:0% +in the in the immediate output doesn't + + + align:start position:0% +in the in the immediate output doesn't +collapse immediately anything and + + align:start position:0% +collapse immediately anything and + + + align:start position:0% +collapse immediately anything and +inflation doesn't be doesn't collapse + + align:start position:0% +inflation doesn't be doesn't collapse + + + align:start position:0% +inflation doesn't be doesn't collapse +immediately but markets realize that + + align:start position:0% +immediately but markets realize that + + + align:start position:0% +immediately but markets realize that +there are Long Bar there lcks but but + + align:start position:0% +there are Long Bar there lcks but but + + + align:start position:0% +there are Long Bar there lcks but but +there is a shock already so so it's + + align:start position:0% +there is a shock already so so it's + + + align:start position:0% +there is a shock already so so it's +likely that these things will + + align:start position:0% +likely that these things will + + + align:start position:0% +likely that these things will +happen and and and and it's likely that + + align:start position:0% +happen and and and and it's likely that + + + align:start position:0% +happen and and and and it's likely that +this will happen and it's also likely + + align:start position:0% +this will happen and it's also likely + + + align:start position:0% +this will happen and it's also likely +that the FED will react to + + align:start position:0% +that the FED will react to + + + align:start position:0% +that the FED will react to +that what should be the reaction of the + + align:start position:0% +that what should be the reaction of the + + + align:start position:0% +that what should be the reaction of the +FED if this stuff gets to be + + align:start position:0% + + + + align:start position:0% + +persistent how do you get out of a shock + + align:start position:0% +persistent how do you get out of a shock + + + align:start position:0% +persistent how do you get out of a shock +like that if you really want to go back + + align:start position:0% + + + + align:start position:0% + +there you cut interest rates okay in the + + align:start position:0% +there you cut interest rates okay in the + + + align:start position:0% +there you cut interest rates okay in the +case of the US they were hiking + + align:start position:0% +case of the US they were hiking + + + align:start position:0% +case of the US they were hiking +interestate because we're deing with + + align:start position:0% +interestate because we're deing with + + + align:start position:0% +interestate because we're deing with +dealing with high inflation this tells + + align:start position:0% +dealing with high inflation this tells + + + align:start position:0% +dealing with high inflation this tells +you well you should slow down the pace + + align:start position:0% +you well you should slow down the pace + + + align:start position:0% +you well you should slow down the pace +of hiking again they don't do it + + align:start position:0% +of hiking again they don't do it + + + align:start position:0% +of hiking again they don't do it +immediately they meet next week but the + + align:start position:0% +immediately they meet next week but the + + + align:start position:0% +immediately they meet next week but the +markets don't need to wait for the FED + + align:start position:0% +markets don't need to wait for the FED + + + align:start position:0% +markets don't need to wait for the FED +they anticipate what the FED is likely + + align:start position:0% +they anticipate what the FED is likely + + + align:start position:0% +they anticipate what the FED is likely +to do okay and they start betting on + + align:start position:0% +to do okay and they start betting on + + + align:start position:0% +to do okay and they start betting on +that so let me show you next a bunch of + + align:start position:0% +that so let me show you next a bunch of + + + align:start position:0% +that so let me show you next a bunch of +charts that show you that someone in the + + align:start position:0% +charts that show you that someone in the + + + align:start position:0% +charts that show you that someone in the +market understand these mechanics okay a + + align:start position:0% +market understand these mechanics okay a + + + align:start position:0% +market understand these mechanics okay a +lot of people because the prices are + + align:start position:0% +lot of people because the prices are + + + align:start position:0% +lot of people because the prices are +moving exactly that + + align:start position:0% + + + + align:start position:0% + +way so + + align:start position:0% +way so + + + align:start position:0% +way so +this is the ER oh this is something this + + align:start position:0% +this is the ER oh this is something this + + + align:start position:0% +this is the ER oh this is something this +is the one year ahead inflation + + align:start position:0% +is the one year ahead inflation + + + align:start position:0% +is the one year ahead inflation +expectation as traded in the market it's + + align:start position:0% +expectation as traded in the market it's + + + align:start position:0% +expectation as traded in the market it's +called inflation break even the one-ear + + align:start position:0% +called inflation break even the one-ear + + + align:start position:0% +called inflation break even the one-ear +inflation break even so if you these + + align:start position:0% +inflation break even so if you these + + + align:start position:0% +inflation break even so if you these +things are traded in the market and you + + align:start position:0% +things are traded in the market and you + + + align:start position:0% +things are traded in the market and you +can trade expected inflation at all the + + align:start position:0% +can trade expected inflation at all the + + + align:start position:0% +can trade expected inflation at all the +maturities you want so this is what the + + align:start position:0% +maturities you want so this is what the + + + align:start position:0% +maturities you want so this is what the +market was expecting before this shock + + align:start position:0% +market was expecting before this shock + + + align:start position:0% +market was expecting before this shock +you know infl we getting hotter and + + align:start position:0% +you know infl we getting hotter and + + + align:start position:0% +you know infl we getting hotter and +hotter numbers so the economy was + + align:start position:0% +hotter numbers so the economy was + + + align:start position:0% +hotter numbers so the economy was +inflation expected inflation as price in + + align:start position:0% +inflation expected inflation as price in + + + align:start position:0% +inflation expected inflation as price in +the market Market was climbing okay one + + align:start position:0% +the market Market was climbing okay one + + + align:start position:0% +the market Market was climbing okay one +year out and then the shock came and + + align:start position:0% +year out and then the shock came and + + + align:start position:0% +year out and then the shock came and +look what happened to expect the + + align:start position:0% +look what happened to expect the + + + align:start position:0% +look what happened to expect the +inflation boom it + + align:start position:0% + + + + align:start position:0% + +collapse okay why is that well people + + align:start position:0% +collapse okay why is that well people + + + align:start position:0% +collapse okay why is that well people +thought this shock that leads to that + + align:start position:0% +thought this shock that leads to that + + + align:start position:0% +thought this shock that leads to that +okay that's what they thought this + + align:start position:0% +okay that's what they thought this + + + align:start position:0% +okay that's what they thought this +bounce was markets got a little excited + + align:start position:0% +bounce was markets got a little excited + + + align:start position:0% +bounce was markets got a little excited +yesterday it was a little risk on + + align:start position:0% +yesterday it was a little risk on + + + align:start position:0% +yesterday it was a little risk on +environment today they lost all that + + align:start position:0% +environment today they lost all that + + + align:start position:0% +environment today they lost all that +but but for a shock I'm going to tell + + align:start position:0% +but but for a shock I'm going to tell + + + align:start position:0% +but but for a shock I'm going to tell +you about in a few minutes + + align:start position:0% +you about in a few minutes + + + align:start position:0% +you about in a few minutes +but anyways but the point I wanted to + + align:start position:0% +but anyways but the point I wanted to + + + align:start position:0% +but anyways but the point I wanted to +highlight is again expected inflation + + align:start position:0% +highlight is again expected inflation + + + align:start position:0% +highlight is again expected inflation +was getting a little out of control and + + align:start position:0% +was getting a little out of control and + + + align:start position:0% +was getting a little out of control and +then this x shock came the the Panic + + align:start position:0% +then this x shock came the the Panic + + + align:start position:0% +then this x shock came the the Panic +shock and then immediately expected + + align:start position:0% +shock and then immediately expected + + + align:start position:0% +shock and then immediately expected +inflation decline because people + + align:start position:0% +inflation decline because people + + + align:start position:0% +inflation decline because people +anticipated something like this okay the + + align:start position:0% +anticipated something like this okay the + + + align:start position:0% +anticipated something like this okay the +market anticipated something like that + + align:start position:0% +market anticipated something like that + + + align:start position:0% +market anticipated something like that +what is + + align:start position:0% +what is + + + align:start position:0% +what is +that this is the the + + align:start position:0% +that this is the the + + + align:start position:0% +that this is the the +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +um the markets expected next hike so + + align:start position:0% +um the markets expected next hike so + + + align:start position:0% +um the markets expected next hike so +March 22nd the the FED will decide on + + align:start position:0% +March 22nd the the FED will decide on + + + align:start position:0% +March 22nd the the FED will decide on +the increase in interest rate remember + + align:start position:0% +the increase in interest rate remember + + + align:start position:0% +the increase in interest rate remember +the FED had decided as I said in the + + align:start position:0% +the FED had decided as I said in the + + + align:start position:0% +the FED had decided as I said in the +previous lecture to go for a path of 50 + + align:start position:0% +previous lecture to go for a path of 50 + + + align:start position:0% +previous lecture to go for a path of 50 +basis points initially very high but + + align:start position:0% +basis points initially very high but + + + align:start position:0% +basis points initially very high but +since a couple of meetings ago they + + align:start position:0% +since a couple of meetings ago they + + + align:start position:0% +since a couple of meetings ago they +decided to slow down to 25 basis points + + align:start position:0% +decided to slow down to 25 basis points + + + align:start position:0% +decided to slow down to 25 basis points +precisely because they want to wait and + + align:start position:0% +precisely because they want to wait and + + + align:start position:0% +precisely because they want to wait and +see a bit what what a mess do we have I + + align:start position:0% +see a bit what what a mess do we have I + + + align:start position:0% +see a bit what what a mess do we have I +mean there's long variable lacks they + + align:start position:0% +mean there's long variable lacks they + + + align:start position:0% +mean there's long variable lacks they +have increased rates a lot and and so on + + align:start position:0% +have increased rates a lot and and so on + + + align:start position:0% +have increased rates a lot and and so on +but so they had gone back to a pace of + + align:start position:0% +but so they had gone back to a pace of + + + align:start position:0% +but so they had gone back to a pace of +25 so if you see in you know somewhere + + align:start position:0% +25 so if you see in you know somewhere + + + align:start position:0% +25 so if you see in you know somewhere +here in in February 22nd if you ask the + + align:start position:0% +here in in February 22nd if you ask the + + + align:start position:0% +here in in February 22nd if you ask the +market what what do you think will be + + align:start position:0% +market what what do you think will be + + + align:start position:0% +market what what do you think will be +the next + + align:start position:0% +the next + + + align:start position:0% +the next +hike there will be lots of answers + + align:start position:0% +hike there will be lots of answers + + + align:start position:0% +hike there will be lots of answers +trades and so on but the the when I say + + align:start position:0% +trades and so on but the the when I say + + + align:start position:0% +trades and so on but the the when I say +answers I mean what is price what is + + align:start position:0% +answers I mean what is price what is + + + align:start position:0% +answers I mean what is price what is +traded this financial instrument the the + + align:start position:0% +traded this financial instrument the the + + + align:start position:0% +traded this financial instrument the the +average answer was 30 basis points 30 + + align:start position:0% +average answer was 30 basis points 30 + + + align:start position:0% +average answer was 30 basis points 30 +basis point is that most of the people + + align:start position:0% +basis point is that most of the people + + + align:start position:0% +basis point is that most of the people +thought that they were going to increase + + align:start position:0% +thought that they were going to increase + + + align:start position:0% +thought that they were going to increase +the the interest rate by 25 basis points + + align:start position:0% +the the interest rate by 25 basis points + + + align:start position:0% +the the interest rate by 25 basis points +and there were a few guys out there that + + align:start position:0% +and there were a few guys out there that + + + align:start position:0% +and there were a few guys out there that +thought the FED doesn't increase the + + align:start position:0% +thought the FED doesn't increase the + + + align:start position:0% +thought the FED doesn't increase the +interest rate by 33 basis points that's + + align:start position:0% +interest rate by 33 basis points that's + + + align:start position:0% +interest rate by 33 basis points that's +25 50 75 okay so this 30 is meant that + + align:start position:0% +25 50 75 okay so this 30 is meant that + + + align:start position:0% +25 50 75 okay so this 30 is meant that +almost everyone thought it was going to + + align:start position:0% +almost everyone thought it was going to + + + align:start position:0% +almost everyone thought it was going to +be 25 but there were a few people that + + align:start position:0% +be 25 but there were a few people that + + + align:start position:0% +be 25 but there were a few people that +were concerned that could be higher than + + align:start position:0% +were concerned that could be higher than + + + align:start position:0% +were concerned that could be higher than +that what happened here we start getting + + align:start position:0% +that what happened here we start getting + + + align:start position:0% +that what happened here we start getting +very hot numbers on inflation and so all + + align:start position:0% +very hot numbers on inflation and so all + + + align:start position:0% +very hot numbers on inflation and so all +of a sudden the equilibrium changed + + align:start position:0% +of a sudden the equilibrium changed + + + align:start position:0% +of a sudden the equilibrium changed +dramatically and we went to 45 which + + align:start position:0% +dramatically and we went to 45 which + + + align:start position:0% +dramatically and we went to 45 which +means most people then thought in the + + align:start position:0% +means most people then thought in the + + + align:start position:0% +means most people then thought in the +market that the next hike in in in on on + + align:start position:0% +market that the next hike in in in on on + + + align:start position:0% +market that the next hike in in in on on +March 22nd was going to be 50 basis + + align:start position:0% +March 22nd was going to be 50 basis + + + align:start position:0% +March 22nd was going to be 50 basis +points and a few people St stay at 25 + + align:start position:0% +points and a few people St stay at 25 + + + align:start position:0% +points and a few people St stay at 25 +that's the reason H this is not 0. five + + align:start position:0% +that's the reason H this is not 0. five + + + align:start position:0% +that's the reason H this is not 0. five +but it was almost price in that point + + align:start position:0% +but it was almost price in that point + + + align:start position:0% +but it was almost price in that point +when people say price in they're talking + + align:start position:0% +when people say price in they're talking + + + align:start position:0% +when people say price in they're talking +about this what is the hike that price + + align:start position:0% +about this what is the hike that price + + + align:start position:0% +about this what is the hike that price +in is this statistic look that's what + + align:start position:0% +in is this statistic look that's what + + + align:start position:0% +in is this statistic look that's what +happened with + + align:start position:0% +happened with + + + align:start position:0% +happened with +the Silicon Valley Bank event okay a + + align:start position:0% +the Silicon Valley Bank event okay a + + + align:start position:0% +the Silicon Valley Bank event okay a +collapse in this thing now now is is + + align:start position:0% +collapse in this thing now now is is + + + align:start position:0% +collapse in this thing now now is is +trading at around 13 basis points that + + align:start position:0% +trading at around 13 basis points that + + + align:start position:0% +trading at around 13 basis points that +means most of the people think that the + + align:start position:0% +means most of the people think that the + + + align:start position:0% +means most of the people think that the +Traders here think that there will be no + + align:start position:0% +Traders here think that there will be no + + + align:start position:0% +Traders here think that there will be no +hike at all okay so a few days ago they + + align:start position:0% +hike at all okay so a few days ago they + + + align:start position:0% +hike at all okay so a few days ago they +all thought there was going to be 50 + + align:start position:0% +all thought there was going to be 50 + + + align:start position:0% +all thought there was going to be 50 +basis point which is a big hike H and + + align:start position:0% +basis point which is a big hike H and + + + align:start position:0% +basis point which is a big hike H and +now most people think there will be no + + align:start position:0% +now most people think there will be no + + + align:start position:0% +now most people think there will be no +hike whatsoever but a few think that + + align:start position:0% +hike whatsoever but a few think that + + + align:start position:0% +hike whatsoever but a few think that +it's going to be 25 me actually it's + + align:start position:0% +it's going to be 25 me actually it's + + + align:start position:0% +it's going to be 25 me actually it's +almost 50/50 no I think today is a + + align:start position:0% +almost 50/50 no I think today is a + + + align:start position:0% +almost 50/50 no I think today is a +little lower than that but it's almost + + align:start position:0% +little lower than that but it's almost + + + align:start position:0% +little lower than that but it's almost +50/50 that is 25 or zero that's that's + + align:start position:0% +50/50 that is 25 or zero that's that's + + + align:start position:0% +50/50 that is 25 or zero that's that's +what what it is but had you ask anyone + + align:start position:0% +what what it is but had you ask anyone + + + align:start position:0% +what what it is but had you ask anyone +around here and certainly around here is + + align:start position:0% +around here and certainly around here is + + + align:start position:0% +around here and certainly around here is +there any chance of zero and there would + + align:start position:0% +there any chance of zero and there would + + + align:start position:0% +there any chance of zero and there would +be no one literally is that contract was + + align:start position:0% +be no one literally is that contract was + + + align:start position:0% +be no one literally is that contract was +not traded okay well you see things + + align:start position:0% +not traded okay well you see things + + + align:start position:0% +not traded okay well you see things +happen accidents happen so now that's + + align:start position:0% +happen accidents happen so now that's + + + align:start position:0% +happen accidents happen so now that's +where where we are + + align:start position:0% +where where we are + + + align:start position:0% +where where we are +at + + align:start position:0% + + + + align:start position:0% + +now if this all last a week and and + + align:start position:0% +now if this all last a week and and + + + align:start position:0% +now if this all last a week and and +everything gets resolved it doesn't have + + align:start position:0% +everything gets resolved it doesn't have + + + align:start position:0% +everything gets resolved it doesn't have +a lot of macro iic consequences okay + + align:start position:0% +a lot of macro iic consequences okay + + + align:start position:0% +a lot of macro iic consequences okay +it's just a little Panic you know some + + align:start position:0% +it's just a little Panic you know some + + + align:start position:0% +it's just a little Panic you know some +people make money some people lose money + + align:start position:0% +people make money some people lose money + + + align:start position:0% +people make money some people lose money +and so on but but but but this can be a + + align:start position:0% +and so on but but but but this can be a + + + align:start position:0% +and so on but but but but this can be a +very problematic shock actually because + + align:start position:0% +very problematic shock actually because + + + align:start position:0% +very problematic shock actually because +what you see here is that this is a size + + align:start position:0% +what you see here is that this is a size + + + align:start position:0% +what you see here is that this is a size +this is Silicon Valley + + align:start position:0% +this is Silicon Valley + + + align:start position:0% +this is Silicon Valley +Bank these are all the rest the banks + + align:start position:0% +Bank these are all the rest the banks + + + align:start position:0% +Bank these are all the rest the banks +smaller than + + align:start position:0% +smaller than + + + align:start position:0% +smaller than +that H it turns out that all these bank + + align:start position:0% +that H it turns out that all these bank + + + align:start position:0% +that H it turns out that all these bank +at this moment are reshuffling their + + align:start position:0% +at this moment are reshuffling their + + + align:start position:0% +at this moment are reshuffling their +portfolios they're becoming very + + align:start position:0% +portfolios they're becoming very + + + align:start position:0% +portfolios they're becoming very +conservative because they don't want to + + align:start position:0% +conservative because they don't want to + + + align:start position:0% +conservative because they don't want to +be exposed to similar risk they realized + + align:start position:0% +be exposed to similar risk they realized + + + align:start position:0% +be exposed to similar risk they realized +the environment became very unfriendly + + align:start position:0% +the environment became very unfriendly + + + align:start position:0% +the environment became very unfriendly +to you know that can be runs on banks in + + align:start position:0% +to you know that can be runs on banks in + + + align:start position:0% +to you know that can be runs on banks in +any moment despite the fact that it's a + + align:start position:0% +any moment despite the fact that it's a + + + align:start position:0% +any moment despite the fact that it's a +big policy package out there but people + + align:start position:0% +big policy package out there but people + + + align:start position:0% +big policy package out there but people +are still withdrawing lots of deposits + + align:start position:0% +are still withdrawing lots of deposits + + + align:start position:0% +are still withdrawing lots of deposits +from a small Banks small and Regional + + align:start position:0% +from a small Banks small and Regional + + + align:start position:0% +from a small Banks small and Regional +Banks and they all deposi it in JP + + align:start position:0% +Banks and they all deposi it in JP + + + align:start position:0% +Banks and they all deposi it in JP +Morgan you know the big Banks so there's + + align:start position:0% +Morgan you know the big Banks so there's + + + align:start position:0% +Morgan you know the big Banks so there's +lots of deposits that despite the the + + align:start position:0% +lots of deposits that despite the the + + + align:start position:0% +lots of deposits that despite the the +the the insurance the the the the the + + align:start position:0% +the the insurance the the the the the + + + align:start position:0% +the the insurance the the the the the +blanket insurance that is implicit at + + align:start position:0% +blanket insurance that is implicit at + + + align:start position:0% +blanket insurance that is implicit at +least at the moment lots of deposits + + align:start position:0% +least at the moment lots of deposits + + + align:start position:0% +least at the moment lots of deposits +from these sectors are moving to these + + align:start position:0% +from these sectors are moving to these + + + align:start position:0% +from these sectors are moving to these +major Banks here okay that's called it's + + align:start position:0% +major Banks here okay that's called it's + + + align:start position:0% +major Banks here okay that's called it's +called a flight to + + align:start position:0% +called a flight to + + + align:start position:0% +called a flight to +Quality now the problem of that for the + + align:start position:0% +Quality now the problem of that for the + + + align:start position:0% +Quality now the problem of that for the +economy as a whole is that small Banks + + align:start position:0% +economy as a whole is that small Banks + + + align:start position:0% +economy as a whole is that small Banks +and Regional Banks play a huge role in + + align:start position:0% +and Regional Banks play a huge role in + + + align:start position:0% +and Regional Banks play a huge role in +in + + align:start position:0% +in + + + align:start position:0% +in +lending okay I + + align:start position:0% +lending okay I + + + align:start position:0% +lending okay I +think a little more than 50% for example + + align:start position:0% +think a little more than 50% for example + + + align:start position:0% +think a little more than 50% for example +of the commercial and Industrial loans + + align:start position:0% +of the commercial and Industrial loans + + + align:start position:0% +of the commercial and Industrial loans +are made by small Banks ER 80% of the + + align:start position:0% +are made by small Banks ER 80% of the + + + align:start position:0% +are made by small Banks ER 80% of the +mortgages are given by a small Banks so + + align:start position:0% +mortgages are given by a small Banks so + + + align:start position:0% +mortgages are given by a small Banks so +it so it has a big + + align:start position:0% +it so it has a big + + + align:start position:0% +it so it has a big +potential consequence what I'm trying to + + align:start position:0% +potential consequence what I'm trying to + + + align:start position:0% +potential consequence what I'm trying to +say is that X may stay high for quite a + + align:start position:0% +say is that X may stay high for quite a + + + align:start position:0% +say is that X may stay high for quite a +bit of time okay and that's a + + align:start position:0% +bit of time okay and that's a + + + align:start position:0% +bit of time okay and that's a +reason this is start there is + + align:start position:0% +reason this is start there is + + + align:start position:0% +reason this is start there is +anticipation that this will have + + align:start position:0% +anticipation that this will have + + + align:start position:0% +anticipation that this will have +macroeconomic consequences and as a + + align:start position:0% +macroeconomic consequences and as a + + + align:start position:0% +macroeconomic consequences and as a +result of that that the FED will react + + align:start position:0% +result of that that the FED will react + + + align:start position:0% +result of that that the FED will react +that inflation will change and all + + align:start position:0% + + + + align:start position:0% + +that okay so that's where we were at on + + align:start position:0% +that okay so that's where we were at on + + + align:start position:0% +that okay so that's where we were at on +Monday remember when we had the lecture + + align:start position:0% +Monday remember when we had the lecture + + + align:start position:0% +Monday remember when we had the lecture +I was telling you more or less that + + align:start position:0% +I was telling you more or less that + + + align:start position:0% +I was telling you more or less that +story ER what is this + + align:start position:0% +story ER what is this + + + align:start position:0% +story ER what is this +you can read it there but it may not + + align:start position:0% +you can read it there but it may not + + + align:start position:0% +you can read it there but it may not +mean M to much to you but I'm what I'm + + align:start position:0% +mean M to much to you but I'm what I'm + + + align:start position:0% +mean M to much to you but I'm what I'm +highlighting is this this is pretty big + + align:start position:0% +highlighting is this this is pretty big + + + align:start position:0% +highlighting is this this is pretty big +huh 35% decline this is an equity it's a + + align:start position:0% +huh 35% decline this is an equity it's a + + + align:start position:0% +huh 35% decline this is an equity it's a +share so this is + + align:start position:0% +share so this is + + + align:start position:0% +share so this is +the the value of the + + align:start position:0% +the the value of the + + + align:start position:0% +the the value of the +equity of a pretty major Bank credit + + align:start position:0% +equity of a pretty major Bank credit + + + align:start position:0% +equity of a pretty major Bank credit +Swiss okay so credit Swiss have been in + + align:start position:0% +Swiss okay so credit Swiss have been in + + + align:start position:0% +Swiss okay so credit Swiss have been in +trouble for a while but today got into + + align:start position:0% +trouble for a while but today got into + + + align:start position:0% +trouble for a while but today got into +really big trouble okay and and and you + + align:start position:0% +really big trouble okay and and and you + + + align:start position:0% +really big trouble okay and and and you +saw sort of a massive collap collapse in + + align:start position:0% +saw sort of a massive collap collapse in + + + align:start position:0% +saw sort of a massive collap collapse in +the equity shares in fact they stopped + + align:start position:0% +the equity shares in fact they stopped + + + align:start position:0% +the equity shares in fact they stopped +trading for a while and so + + align:start position:0% +trading for a while and so + + + align:start position:0% +trading for a while and so +on this thing here is H you know I + + align:start position:0% +on this thing here is H you know I + + + align:start position:0% +on this thing here is H you know I +updated your slides many times today + + align:start position:0% +updated your slides many times today + + + align:start position:0% +updated your slides many times today +because I began to look at this event + + align:start position:0% +because I began to look at this event + + + align:start position:0% +because I began to look at this event +around here and then this thing kept + + align:start position:0% +around here and then this thing kept + + + align:start position:0% +around here and then this thing kept +going then they stop kept going and so + + align:start position:0% +going then they stop kept going and so + + + align:start position:0% +going then they stop kept going and so +and I I'm not sure where it's at now I + + align:start position:0% +and I I'm not sure where it's at now I + + + align:start position:0% +and I I'm not sure where it's at now I +stopped at what time did I stop 9 in the + + align:start position:0% +stopped at what time did I stop 9 in the + + + align:start position:0% +stopped at what time did I stop 9 in the +morning I was awake at 4:44 today so + + align:start position:0% +morning I was awake at 4:44 today so + + + align:start position:0% +morning I was awake at 4:44 today so +they tell you this was this was a pretty + + align:start position:0% +they tell you this was this was a pretty + + + align:start position:0% +they tell you this was this was a pretty +intense um but this what this is is the + + align:start position:0% +intense um but this what this is is the + + + align:start position:0% +intense um but this what this is is the +credit default swaps on a credit swis + + align:start position:0% +credit default swaps on a credit swis + + + align:start position:0% +credit default swaps on a credit swis +credit swap is whenever it's a bond + + align:start position:0% +credit swap is whenever it's a bond + + + align:start position:0% +credit swap is whenever it's a bond +issued by a bank you can buy an + + align:start position:0% +issued by a bank you can buy an + + + align:start position:0% +issued by a bank you can buy an +insurance on that Bond okay so it's so + + align:start position:0% +insurance on that Bond okay so it's so + + + align:start position:0% +insurance on that Bond okay so it's so +so if the bond defaults on you you then + + align:start position:0% +so if the bond defaults on you you then + + + align:start position:0% +so if the bond defaults on you you then +use the insurance and you get + + align:start position:0% +use the insurance and you get + + + align:start position:0% +use the insurance and you get +paid so these things for banks normally + + align:start position:0% +paid so these things for banks normally + + + align:start position:0% +paid so these things for banks normally +are very small numbers but for credit SS + + align:start position:0% +are very small numbers but for credit SS + + + align:start position:0% +are very small numbers but for credit SS +bigger than for other big Banks because + + align:start position:0% +bigger than for other big Banks because + + + align:start position:0% +bigger than for other big Banks because +I've been in in trouble for a while all + + align:start position:0% +I've been in in trouble for a while all + + + align:start position:0% +I've been in in trouble for a while all +sort of trouble but look at that Spike + + align:start position:0% +sort of trouble but look at that Spike + + + align:start position:0% +sort of trouble but look at that Spike +there I mean that's pretty big for these + + align:start position:0% +there I mean that's pretty big for these + + + align:start position:0% +there I mean that's pretty big for these +kind of things you know it's not Lon yet + + align:start position:0% +kind of things you know it's not Lon yet + + + align:start position:0% +kind of things you know it's not Lon yet +but + + align:start position:0% +but + + + align:start position:0% +but +big so anyway that caused a little Panic + + align:start position:0% +big so anyway that caused a little Panic + + + align:start position:0% +big so anyway that caused a little Panic +today + + align:start position:0% +today + + + align:start position:0% +today +ER this is the the stock prices of the + + align:start position:0% +ER this is the the stock prices of the + + + align:start position:0% +ER this is the the stock prices of the +main European Banks this is all today + + align:start position:0% +main European Banks this is all today + + + align:start position:0% +main European Banks this is all today +yeah so look at this it was a little + + align:start position:0% +yeah so look at this it was a little + + + align:start position:0% +yeah so look at this it was a little +rally yesterday and so on I mean this is + + align:start position:0% +rally yesterday and so on I mean this is + + + align:start position:0% +rally yesterday and so on I mean this is +this is the decline as a result of the + + align:start position:0% +this is the decline as a result of the + + + align:start position:0% +this is the decline as a result of the +US problem the Silicon Valley Banks then + + align:start position:0% +US problem the Silicon Valley Banks then + + + align:start position:0% +US problem the Silicon Valley Banks then +a rally yesterday and then credit Swiss + + align:start position:0% +a rally yesterday and then credit Swiss + + + align:start position:0% +a rally yesterday and then credit Swiss +happen and you has a big decline in h in + + align:start position:0% +happen and you has a big decline in h in + + + align:start position:0% +happen and you has a big decline in h in +in all the major banks in in Europe the + + align:start position:0% +in all the major banks in in Europe the + + + align:start position:0% +in all the major banks in in Europe the +US banks are also declining but but that + + align:start position:0% +US banks are also declining but but that + + + align:start position:0% +US banks are also declining but but that +was bigger for the major + + align:start position:0% +was bigger for the major + + + align:start position:0% +was bigger for the major +Banks the vix remember I told you last + + align:start position:0% +Banks the vix remember I told you last + + + align:start position:0% +Banks the vix remember I told you last +last week last Monday about this + + align:start position:0% +last week last Monday about this + + + align:start position:0% +last week last Monday about this +indicator of fear in the market which is + + align:start position:0% +indicator of fear in the market which is + + + align:start position:0% +indicator of fear in the market which is +really the price put options I'm + + align:start position:0% +really the price put options I'm + + + align:start position:0% +really the price put options I'm +simplifying things I mean protection for + + align:start position:0% +simplifying things I mean protection for + + + align:start position:0% +simplifying things I mean protection for +for big declines on the equity Market H + + align:start position:0% +for big declines on the equity Market H + + + align:start position:0% +for big declines on the equity Market H +again it began to spike very very + + align:start position:0% +again it began to spike very very + + + align:start position:0% +again it began to spike very very +sharply as a result of this is what + + align:start position:0% +sharply as a result of this is what + + + align:start position:0% +sharply as a result of this is what +happened with the US event then + + align:start position:0% +happened with the US event then + + + align:start position:0% +happened with the US event then +yesterday we got a rally Rison type + + align:start position:0% +yesterday we got a rally Rison type + + + align:start position:0% +yesterday we got a rally Rison type +thing and then today we got a new + + align:start position:0% +thing and then today we got a new + + + align:start position:0% +thing and then today we got a new +event look at this I like this + + align:start position:0% +event look at this I like this + + + align:start position:0% +event look at this I like this +picture what this is let me let me tell + + align:start position:0% +picture what this is let me let me tell + + + align:start position:0% +picture what this is let me let me tell +you what the the the the the blue line + + align:start position:0% +you what the the the the the blue line + + + align:start position:0% +you what the the the the the blue line +is the blue line is is the + + align:start position:0% +is the blue line is is the + + + align:start position:0% +is the blue line is is the +market ER + + align:start position:0% +market ER + + + align:start position:0% +market ER +expected federal funds rate at different + + align:start position:0% +expected federal funds rate at different + + + align:start position:0% +expected federal funds rate at different +days in the future okay so you know + + align:start position:0% +days in the future okay so you know + + + align:start position:0% +days in the future okay so you know +today the federal funds rate is is is + + align:start position:0% +today the federal funds rate is is is + + + align:start position:0% +today the federal funds rate is is is +around four and a half and this is what + + align:start position:0% +around four and a half and this is what + + + align:start position:0% +around four and a half and this is what +what the market expects okay so they + + align:start position:0% +what the market expects okay so they + + + align:start position:0% +what the market expects okay so they +expected so they expected the FED to + + align:start position:0% +expected so they expected the FED to + + + align:start position:0% +expected so they expected the FED to +continue to hike interest rate and to + + align:start position:0% +continue to hike interest rate and to + + + align:start position:0% +continue to hike interest rate and to +reach a peak + + align:start position:0% +reach a peak + + + align:start position:0% +reach a peak +ER around in June 14th in that meeting + + align:start position:0% +ER around in June 14th in that meeting + + + align:start position:0% +ER around in June 14th in that meeting +of the order of five five 5.3% or so + + align:start position:0% +of the order of five five 5.3% or so + + + align:start position:0% +of the order of five five 5.3% or so +that's that's what the average there + + align:start position:0% +that's that's what the average there + + + align:start position:0% +that's that's what the average there +lots of dispersion there people betting + + align:start position:0% +lots of dispersion there people betting + + + align:start position:0% +lots of dispersion there people betting +on 6% but that's the average that's what + + align:start position:0% +on 6% but that's the average that's what + + + align:start position:0% +on 6% but that's the average that's what +people expected the yellow thinks it's + + align:start position:0% +people expected the yellow thinks it's + + + align:start position:0% +people expected the yellow thinks it's +the number of hikes that you're likely + + align:start position:0% +the number of hikes that you're likely + + + align:start position:0% +the number of hikes that you're likely +to see so you know you're likely to see + + align:start position:0% +to see so you know you're likely to see + + + align:start position:0% +to see so you know you're likely to see +one hike in the next meeting another one + + align:start position:0% +one hike in the next meeting another one + + + align:start position:0% +one hike in the next meeting another one +in the next meeting and another one in + + align:start position:0% +in the next meeting and another one in + + + align:start position:0% +in the next meeting and another one in +the next meeting and then stop and begin + + align:start position:0% +the next meeting and then stop and begin + + + align:start position:0% +the next meeting and then stop and begin +sort of cutting rates that's expect that + + align:start position:0% +sort of cutting rates that's expect that + + + align:start position:0% +sort of cutting rates that's expect that +was expected path on Friday 10th was + + align:start position:0% +was expected path on Friday 10th was + + + align:start position:0% +was expected path on Friday 10th was +Friday more or less around there maybe + + align:start position:0% +Friday more or less around there maybe + + + align:start position:0% +Friday more or less around there maybe +Thursday I don't remember but anyway + + align:start position:0% +Thursday I don't remember but anyway + + + align:start position:0% +Thursday I don't remember but anyway +that was expected path you see so still + + align:start position:0% +that was expected path you see so still + + + align:start position:0% +that was expected path you see so still +hike rates reach a peak of five 5.3% and + + align:start position:0% +hike rates reach a peak of five 5.3% and + + + align:start position:0% +hike rates reach a peak of five 5.3% and +still sort of pretty high interest rates + + align:start position:0% +still sort of pretty high interest rates + + + align:start position:0% +still sort of pretty high interest rates +by the end of the year okay that was + + align:start position:0% +by the end of the year okay that was + + + align:start position:0% +by the end of the year okay that was +expected + + align:start position:0% + + + + align:start position:0% + +path that's the way it looks + + align:start position:0% +path that's the way it looks + + + align:start position:0% +path that's the way it looks +now very different no now + + align:start position:0% +now very different no now + + + align:start position:0% +now very different no now +people are expecting very small changes + + align:start position:0% +people are expecting very small changes + + + align:start position:0% +people are expecting very small changes +now I show you it's like 13 basis points + + align:start position:0% +now I show you it's like 13 basis points + + + align:start position:0% +now I show you it's like 13 basis points +what people expect okay the still people + + align:start position:0% +what people expect okay the still people + + + align:start position:0% +what people expect okay the still people +expect sort of a hike but but small one + + align:start position:0% +expect sort of a hike but but small one + + + align:start position:0% +expect sort of a hike but but small one +now they expect a peak to be sort of in + + align:start position:0% +now they expect a peak to be sort of in + + + align:start position:0% +now they expect a peak to be sort of in +May and then the FED to start cutting + + align:start position:0% +May and then the FED to start cutting + + + align:start position:0% +May and then the FED to start cutting +very aggressively to at the end of the + + align:start position:0% +very aggressively to at the end of the + + + align:start position:0% +very aggressively to at the end of the +year end up with much lower rates than + + align:start position:0% +year end up with much lower rates than + + + align:start position:0% +year end up with much lower rates than +today + + align:start position:0% +today + + + align:start position:0% +today +okay so this is exactly what I was + + align:start position:0% +okay so this is exactly what I was + + + align:start position:0% +okay so this is exactly what I was +telling you before the market is + + align:start position:0% +telling you before the market is + + + align:start position:0% +telling you before the market is +anticipating that that we had a huge + + align:start position:0% +anticipating that that we had a huge + + + align:start position:0% +anticipating that that we had a huge +contraction in the is because X went up + + align:start position:0% +contraction in the is because X went up + + + align:start position:0% +contraction in the is because X went up +a lot ER the immediate consequences + + align:start position:0% +a lot ER the immediate consequences + + + align:start position:0% +a lot ER the immediate consequences +that's going to be lower inflation yes + + align:start position:0% +that's going to be lower inflation yes + + + align:start position:0% +that's going to be lower inflation yes +we have a problem because I mean if if + + align:start position:0% +we have a problem because I mean if if + + + align:start position:0% +we have a problem because I mean if if +the US did not have a 5 and a half% of + + align:start position:0% +the US did not have a 5 and a half% of + + + align:start position:0% +the US did not have a 5 and a half% of +inflation + + align:start position:0% +inflation + + + align:start position:0% +inflation +today I can assure you that the FED + + align:start position:0% +today I can assure you that the FED + + + align:start position:0% +today I can assure you that the FED +would have come out and said we cut the + + align:start position:0% +would have come out and said we cut the + + + align:start position:0% +would have come out and said we cut the +rates right now the only reason they're + + align:start position:0% +rates right now the only reason they're + + + align:start position:0% +rates right now the only reason they're +not cutting right now is because we have + + align:start position:0% +not cutting right now is because we have + + + align:start position:0% +not cutting right now is because we have +a two problems we have the the financial + + align:start position:0% +a two problems we have the the financial + + + align:start position:0% +a two problems we have the the financial +Panic on one side and we have the High + + align:start position:0% +Panic on one side and we have the High + + + align:start position:0% +Panic on one side and we have the High +inflation on the other side so so they + + align:start position:0% +inflation on the other side so so they + + + align:start position:0% +inflation on the other side so so they +have to balance these two + + align:start position:0% +have to balance these two + + + align:start position:0% +have to balance these two +forces but but the expectation of the + + align:start position:0% +forces but but the expectation of the + + + align:start position:0% +forces but but the expectation of the +market is that the balance of two forces + + align:start position:0% +market is that the balance of two forces + + + align:start position:0% +market is that the balance of two forces +going to be dominated by the contraction + + align:start position:0% +going to be dominated by the contraction + + + align:start position:0% +going to be dominated by the contraction +and aggregate demand much sooner than + + align:start position:0% +and aggregate demand much sooner than + + + align:start position:0% +and aggregate demand much sooner than +people were expecting okay so that's + + align:start position:0% +people were expecting okay so that's + + + align:start position:0% +people were expecting okay so that's +what the market is pricing at the moment + + align:start position:0% +what the market is pricing at the moment + + + align:start position:0% +what the market is pricing at the moment +and what I'm saying is I was trying to + + align:start position:0% +and what I'm saying is I was trying to + + + align:start position:0% +and what I'm saying is I was trying to +highlight is that this is very + + align:start position:0% +highlight is that this is very + + + align:start position:0% +highlight is that this is very +consistent with + + align:start position:0% + + + + align:start position:0% + +h with that okay it's just the market + + align:start position:0% +h with that okay it's just the market + + + align:start position:0% +h with that okay it's just the market +looking ahead of what it's likely to + + align:start position:0% +looking ahead of what it's likely to + + + align:start position:0% +looking ahead of what it's likely to +Happ happen it started from a situation + + align:start position:0% +Happ happen it started from a situation + + + align:start position:0% +Happ happen it started from a situation +which is a little bit more complicated + + align:start position:0% +which is a little bit more complicated + + + align:start position:0% +which is a little bit more complicated +again because we already had high + + align:start position:0% +again because we already had high + + + align:start position:0% +again because we already had high +inflation well I do not know really I + + align:start position:0% +inflation well I do not know really I + + + align:start position:0% +inflation well I do not know really I +mean it is on one end more complicated + + align:start position:0% +mean it is on one end more complicated + + + align:start position:0% +mean it is on one end more complicated +because we have a problem of high + + align:start position:0% +because we have a problem of high + + + align:start position:0% +because we have a problem of high +inflation on the other hand having high + + align:start position:0% +inflation on the other hand having high + + + align:start position:0% +inflation on the other hand having high +inflation allows you to cut the real + + align:start position:0% +inflation allows you to cut the real + + + align:start position:0% +inflation allows you to cut the real +interest rate much more aggressively + + align:start position:0% +interest rate much more aggressively + + + align:start position:0% +interest rate much more aggressively +because if you bring the nominal + + align:start position:0% +because if you bring the nominal + + + align:start position:0% +because if you bring the nominal +interest rate to zero and you have + + align:start position:0% +interest rate to zero and you have + + + align:start position:0% +interest rate to zero and you have +inflation of 5% that allows you to cut + + align:start position:0% +inflation of 5% that allows you to cut + + + align:start position:0% +inflation of 5% that allows you to cut +the real interest rate to minus 5% well + + align:start position:0% +the real interest rate to minus 5% well + + + align:start position:0% +the real interest rate to minus 5% well +if you start with a situation where your + + align:start position:0% +if you start with a situation where your + + + align:start position:0% +if you start with a situation where your +inflation is zero you don't have any + + align:start position:0% +inflation is zero you don't have any + + + align:start position:0% +inflation is zero you don't have any +space to cut the real interest rate so + + align:start position:0% +space to cut the real interest rate so + + + align:start position:0% +space to cut the real interest rate so +the FED can be very aggressive here and + + align:start position:0% +the FED can be very aggressive here and + + + align:start position:0% +the FED can be very aggressive here and +the only reason is not being very very + + align:start position:0% +the only reason is not being very very + + + align:start position:0% +the only reason is not being very very +aggressive they were very aggressive in + + align:start position:0% +aggressive they were very aggressive in + + + align:start position:0% +aggressive they were very aggressive in +terms of supporting deposits and all + + align:start position:0% +terms of supporting deposits and all + + + align:start position:0% +terms of supporting deposits and all +that but the the the the the they can be + + align:start position:0% +that but the the the the the they can be + + + align:start position:0% +that but the the the the the they can be +very aggressive in terms of interest + + align:start position:0% +very aggressive in terms of interest + + + align:start position:0% +very aggressive in terms of interest +rate cut if the need arises hopefully + + align:start position:0% +rate cut if the need arises hopefully + + + align:start position:0% +rate cut if the need arises hopefully +won't but but they have a space because + + align:start position:0% +won't but but they have a space because + + + align:start position:0% +won't but but they have a space because +we're starting from a much higher level + + align:start position:0% +we're starting from a much higher level + + + align:start position:0% +we're starting from a much higher level +of inflation that + + align:start position:0% +of inflation that + + + align:start position:0% +of inflation that +helps it it hurts in the sense that it + + align:start position:0% +helps it it hurts in the sense that it + + + align:start position:0% +helps it it hurts in the sense that it +will delay the reaction but it helps in + + align:start position:0% +will delay the reaction but it helps in + + + align:start position:0% +will delay the reaction but it helps in +the sense that they have much more space + + align:start position:0% +the sense that they have much more space + + + align:start position:0% +the sense that they have much more space +for for + + align:start position:0% + + + + align:start position:0% + +policy what is + + align:start position:0% + + + + align:start position:0% + +this oh this is just interest one year + + align:start position:0% +this oh this is just interest one year + + + align:start position:0% +this oh this is just interest one year +interest rates okay that that reflects + + align:start position:0% +interest rates okay that that reflects + + + align:start position:0% +interest rates okay that that reflects +the the the previous picture as well + + align:start position:0% +the the the previous picture as well + + + align:start position:0% +the the the previous picture as well +people you know one year out rates were + + align:start position:0% +people you know one year out rates were + + + align:start position:0% +people you know one year out rates were +over + + align:start position:0% +over + + + align:start position:0% +over +5% uh a few days ago and now are in the + + align:start position:0% +5% uh a few days ago and now are in the + + + align:start position:0% +5% uh a few days ago and now are in the +low + + align:start position:0% +low + + + align:start position:0% +low +force and this picture I kept updating + + align:start position:0% +force and this picture I kept updating + + + align:start position:0% +force and this picture I kept updating +as you can see it was really dropping + + align:start position:0% + + + + align:start position:0% + +fast that's a big change me look the one + + align:start position:0% +fast that's a big change me look the one + + + align:start position:0% +fast that's a big change me look the one +year rate 60 basis points that's a big + + align:start position:0% + + + + align:start position:0% + +change so that's where we're + + align:start position:0% +change so that's where we're + + + align:start position:0% +change so that's where we're +at I'm from the next lecture I want to + + align:start position:0% +at I'm from the next lecture I want to + + + align:start position:0% +at I'm from the next lecture I want to +start with growth but any questions + + align:start position:0% +start with growth but any questions + + + align:start position:0% +start with growth but any questions +about this or + + align:start position:0% + + + + align:start position:0% + +no okay I don't want to start growth now + + align:start position:0% +no okay I don't want to start growth now + + + align:start position:0% +no okay I don't want to start growth now +in four minutes but uh so the set of + + align:start position:0% +in four minutes but uh so the set of + + + align:start position:0% +in four minutes but uh so the set of +topics we're going to discuss from the + + align:start position:0% +topics we're going to discuss from the + + + align:start position:0% +topics we're going to discuss from the +next lecture are very + + align:start position:0% +next lecture are very + + + align:start position:0% +next lecture are very +different ER subject to not having any + + align:start position:0% +different ER subject to not having any + + + align:start position:0% +different ER subject to not having any +major events if there is a major major + + align:start position:0% +major events if there is a major major + + + align:start position:0% +major events if there is a major major +event I'm going to reffle things so we + + align:start position:0% +event I'm going to reffle things so we + + + align:start position:0% +event I'm going to reffle things so we +can talk about financial panics and + + align:start position:0% +can talk about financial panics and + + + align:start position:0% +can talk about financial panics and +things of that kind let's hope that it + + align:start position:0% +things of that kind let's hope that it + + + align:start position:0% +things of that kind let's hope that it +can stick to the program and do + + align:start position:0% +can stick to the program and do + + + align:start position:0% +can stick to the program and do +growth in the in the next week okay good + + align:start position:0% +growth in the in the next week okay good + + + align:start position:0% +growth in the in the next week okay good +or would we do \ No newline at end of file