Weyl group actions on the Springer sheaf

Pramod N. Achar, Anthony Henderson, Daniel Juteau and Simon Riche

Abstract

We show that two Weyl group actions on the Springer sheaf with arbitrary coefficients, one defined by Fourier transform and one by restriction, agree up to a twist by the sign character. This generalizes a familiar result from the setting of \(\ell\)-adic cohomology, making it applicable to modular representation theory. We use the Weyl group actions to define a Springer correspondence in this generality, and identify the zero weight spaces of small representations in terms of this Springer correspondence.

AMS Subject Classification: Primary 17B08, 20G05; Secondary 14M15.