数论与表示论讨论班

Number Theory and Representation Theory Seminar

Time: May 31, Wednesday, 15:00-16:00

Venue: 数学高等研究院Lecture Hall

Speaker: 聂思安Sian Nie (Academy of Mathematics and Systems Science)

Title: Steinberg’s cross-section of Newton strata

Abstract: Let G be a simply connected semisimple group of rank r over an algebraically closed field. Steinberg has associated to each minimal length Coxeter element an r-dimensional affine space in G, which is a cross-section of all regular conjugacy classes of G. In this talk, we will consider natural analogues of Steinberg’s cross-sections in the context of a loop group equipped with a Frobenius automorphism. We will show how Steinberg’s cross-sections intersect Frobenius twisted conjugacy classes (which are parameterized by "Newton polygons"). Some interesting applications will also be discussed.

简介

聂思安，中科院数学所研究员。本科毕业于浙江大学竺可桢学院，硕博毕业于中科院数学所，导师席南华院士。研究方向为代数群、仿射Hecke代数及其表示理论，仿射Deligne-Lusztig簇的几何及其在算数几何中的应用。做出多项重要研究成果， 发表在Duke. J. Math., Math. Ann., Ann. Sci. Ec. Norm. Super., Amer. J. math., Composito Math 等著名杂志。