CFT 2011

Kac-Moody groups are analogues of the Chevalley groups, for infinite-dimensional Lie algebras. Tits proved that they are characterized by certain natural properties (at least over fields), so one can speak of "the" Kac-Moody groups, and he gave presentations for them. These presentations are elaborations of Steinberg's presentation for Chevalley groups, and are "very infinite"---even over finite fields the relations are parameterized by pairs of not-necessarily simple roots with certain properties. We have shown that in many cases, including the affine cases and some hyperbolic cases like E10, one may massage the presentation until it is a finite, if the base ring is finitely generated as a ring. The key ingredients are an understanding of centralizers in Coxeter groups and a geometric argument in hyperbolic space. (Joint work with Lisa Carbone)

Freitag, den 23. September 2011 um 11:30 Uhr, in INF288, HS1 Freitag, den 23. September 2011 at 11:30, in INF288, HS1