# Geometric and Modular Representation Theory Seminar

## The linkage principle and the tilting character formula via Smith-Treumann theory

The linkage principle says that the category of representations of a reductive group $G$ in positive characteristic decomposes into "blocks" controlled by the affine Weyl group. We will discuss the beautiful geometric proof of this result that Simon Riche and Geordie Williamson obtained by applying Smith-Treumann theory to the Iwahori-Whittaker model of the Satake category... and, as a bonus, a tilting character formula valid for all dominant weights and all characteristics!

### Date & Time

January 20, 2021 | 3:00pm – 5:00pm

### Location

Simonyi Hall 101 and Remote Access

### Speaker Affiliation

CNRS, Université Paris Diderot; Member, School of Mathematics