中国科学院数学与系统科学研究院

数学研究所

学术报告

表示论研讨班

报告人: Prof. Cédric Bonnafé (CNRS & Université de Montpellier)

题  目：Braid group actions on the cohomology of Deligne-Lusztig varieties

时  间：2024年10月25日（星期五）下午16:00-17:00

地  点：南楼N820

摘  要：If G is a finite reductive group, Deligne-Lusztig theory aims to construct representations of G on the ℓ-adic cohomology of certain G-varieties (now called Deligne-Lusztig varieties). Knowing the endomorphism algebra of such representations would be a first step in a complete understanding of their decomposition into irreducible components. We present here a way to construct many elements of these endomorphism algebras, involving a categorical action of the braid group on the derived category of constructible sheaves on the flag variety. This a joint work with Broué, Dudas, Michel and Rouquier.