Abstract Peter Fiebig

Peter Fiebig will speak on

Moment graphs, parity sheaves and representation theory

Abstract: Moment graphs are combinatorial objects that appear in several seemingly distinct areas of mathematics. On the one hand side, they can form the 1-skeleton of torus actions on complex algebraic varieties. On the other hand they occur in the representation theory of Lie algebras. I want to show how these graphs can be used to translate character problems in the representation theory to a multiplicity problem of parity sheaves on flag manifolds. I will focus on the (much easier but still very interesting) case of characteristic 0 coefficients. The modular variant of this is currently on of the cornerstones in recent approaches towards Lusztig's conjecture. I will talk about this in the Oberseminar today.