tag:blogger.com,1999:blog-8759090.post114126048488675031..comments2023-12-29T05:03:38.238+00:00Comments on P.P. Cook's Tangent Space: Classifying Rational Conformal Field TheoriesAnonymoushttp://www.blogger.com/profile/00266156201156998028noreply@blogger.comBlogger10125tag:blogger.com,1999:blog-8759090.post-1141932147487519572006-03-09T19:22:00.000+00:002006-03-09T19:22:00.000+00:00Terry Gannon is currently my next-door office neig...Terry Gannon is currently my next-door office neighbour. But he travels so much that I almost see more reports about his talks on the internet than I see the man in person. ;-)<BR/><BR/>Let me just point out a couple of possibly interesting relations to the stuff you talked about.<BR/><BR/>Modular functions for RCFTs can be constructed rigorously using the Fuchs/Runkel/Schweigert <A HREF="http://golem.ph.utexas.edu/string/archives/000747.html" REL="nofollow">formalism</A>. We are working on showing that this formalism is the result of computing certain <A HREF="http://golem.ph.utexas.edu/string/archives/000753.html" REL="nofollow">2-transport</A> over the worldsheet.<BR/><BR/>This would be interesting, because mathematicians <A HREF="http://golem.ph.utexas.edu/string/archives/000761.html" REL="nofollow">expect</A> that such surface transport which reproduces modular functions gives a geometric realization of <A HREF="http://golem.ph.utexas.edu/string/archives/000737.html" REL="nofollow">elliptic cohomology</A>.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-8759090.post-1141841161022843042006-03-08T18:06:00.000+00:002006-03-08T18:06:00.000+00:00Well say hello to Bill from me (Dan Piponi).> he w...Well say hello to Bill from me (Dan Piponi).<BR/><BR/>> he was talking about trying to explain<BR/>> the link without appeal to the machinery<BR/>> of conformal field theory<BR/><BR/>Even more interesting.sigfpehttps://www.blogger.com/profile/08096190433222340957noreply@blogger.comtag:blogger.com,1999:blog-8759090.post-1141739498214384282006-03-07T13:51:00.000+00:002006-03-07T13:51:00.000+00:00Hi Sigfpe,Yes I see Bill Harvey around semi-regula...Hi Sigfpe,<BR/><BR/>Yes I see Bill Harvey around semi-regularly - he organises the mathematical department colloquia and organises us all into going for dinner afterwards (this is always good, Bill picks good restaurants). Of course sometimes I see him out running (him, not me!) on the streets. All in all, he remains a pretty amazing fellow.<BR/><BR/>Now, I should clear up something that came up in the comments. After speaking to Terry again, it became clear that the "mystery" he referred to was why the ADE classification pops up when you look at modular invariants - he was talking about trying to explain the link without appeal to the machinery of conformal field theory. Meanwhile I'm still trying banging my head against the cft stuff...Anonymoushttps://www.blogger.com/profile/00266156201156998028noreply@blogger.comtag:blogger.com,1999:blog-8759090.post-1141681500434618912006-03-06T21:45:00.000+00:002006-03-06T21:45:00.000+00:00Hey PP Cook,Do you ever see Bill Harvey these days...Hey PP Cook,<BR/><BR/>Do you ever see Bill Harvey these days? I don't know if he's retired yet. <BR/><BR/>I did my PhD in Riemann Surfaces at King's under Bill. Even though I was a pure mathematician I still read a lot of physics looking for neat stuff that could be made 'rigorizable'. Ginsparg's notes on CFT were invaluable. Wish I understood this classification a bit better though...sigfpehttps://www.blogger.com/profile/08096190433222340957noreply@blogger.comtag:blogger.com,1999:blog-8759090.post-1141506910772685202006-03-04T21:15:00.000+00:002006-03-04T21:15:00.000+00:00Thanks to Paul (and at second remove Terry) for a ...Thanks to Paul (and at second remove Terry) for a very helpful post.<BR/><BR/>Re the explanation of ADE discussed above: I get the impression all of Gannon's work is mathematically rigorous. Do you folks know if hep-th/0006247 has been rigorized/is rigorizable?<BR/><BR/>(Sorry for the ugly adjective.)Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-8759090.post-1141467968102831352006-03-04T10:26:00.000+00:002006-03-04T10:26:00.000+00:00Thank-you. That's a great paper you've highlighted...Thank-you. That's a great paper you've highlighted. Now I'm digesting it...Anonymoushttps://www.blogger.com/profile/00266156201156998028noreply@blogger.comtag:blogger.com,1999:blog-8759090.post-1141407474591281222006-03-03T17:37:00.000+00:002006-03-03T17:37:00.000+00:00Sure, have a look at: hep-th/0006247Sure, have a look at: hep-th/0006247Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-8759090.post-1141325954890705582006-03-02T18:59:00.000+00:002006-03-02T18:59:00.000+00:00I don't suppose you could suggest a link to help r...I don't suppose you could suggest a link to help remove the mystery for me?<BR/><BR/>Thanks.Anonymoushttps://www.blogger.com/profile/00266156201156998028noreply@blogger.comtag:blogger.com,1999:blog-8759090.post-1141324892897002442006-03-02T18:41:00.000+00:002006-03-02T18:41:00.000+00:00> ... all the numbers appearing in the classificat...> ... all the numbers appearing in the classification do indeed have an intimate and mysterious (to this day...) relation with the groups A, D, E, ...<BR/><BR/>Not mysterious any more. One just has to go to boundary CFT to find the explanation: D-branes on ALE spaces provide the link between the ADE classification of modular invariants, root systems of type ADE, and singularities of type ADE.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-8759090.post-1141314932928219622006-03-02T15:55:00.000+00:002006-03-02T15:55:00.000+00:00Paul, this was very interesting, thanks!zPaul, this was very interesting, thanks!<BR/><BR/>zAnonymousnoreply@blogger.com