Strata of Weyl groups

Abstract

A Weyl group W is a union of strata (certain subsets which are unions of conjugacy classes) which are the nonempty fibres of a map from W to the set of irreducible representations of W. We give an explicit description of strata in terms of a certain modified centralizer group. We also define superstrata of a connected reductive group and state a conjecture about them.

14 pages