A stacky generalized Springer correspondence and rigid enhancements of L-parameters

Abstract

Motivated by applications to the Langlands program, Aubert-Moussaoui-Solleveld extended Lusztig's generalized Springer correspondence to disconnected reductive groups. We use stacks to give a more geometric account of their theory, in particular, formulating a truly geometric version of the (relevant analogue of the) Bernstein-Zelevinsky Geometrical Lemma and explaining how to compare the correspondence on the group and the Lie algebra using quasi-logarithms. As an application, we study Kaletha's rigid enhancements of L-parameters and draw the same conclusions as Aubert-Moussaoui-Solleveld for this enhancement: there exists a cuspidal support map and its fibers are parameterized by irreducible representations of twisted group algebras.