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SUMMARY:2d CFTs\, Borcherds products and hyperbolization of affine Lie alg
 ebras
DTSTART:20231128T130000Z
DTEND:20231128T150000Z
DTSTAMP:20260827T120900Z
UID:indico-event-454@indico.hiskp.uni-bonn.de
DESCRIPTION:Speakers: Kaiwen Sun (Uppsala University)\n\nIn 1983\, Feingol
 d and Frenkel posed a question about possible relations between affine Lie
  algebras\, hyperbolic Kac-Moody algebras and Siegel modular forms. We giv
 e an automorphic answer to this question and its generalization. We classi
 fy hyperbolic Borcherds-Kac-Moody superalgebras whose super-denominators d
 efine reflective automorphic products of singular weight. As a consequence
 \, we prove that there are exactly 81 affine Lie algebras which have nice 
 extensions to hyperbolic BKM superalgebras. We find that 69 of them appear
  in Schellekens’ list of holomorphic CFT of central charge 24\, while 8 
 of them correspond to the N=1 structures of holomorphic SCFT of central ch
 arge 12 composed of 24 chiral fermions. The last 4 cases are related to ex
 ceptional modular invariants from nontrivial automorphisms of fusion algeb
 ras. This is based on a to-appear paper joint with Haowu Wang and Brandon 
 Williams.\n\nhttps://indico.hiskp.uni-bonn.de/event/454/
URL:https://indico.hiskp.uni-bonn.de/event/454/
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