Unipotent character sheaves and strata of a reductive group

Abstract

Let H H be a connected reductive group over an algebraically closed field. We define a surjective map from the set C S ( H ) CS(H) of unipotent character sheaves on H H (up to isomorphism) to the set of strata of H H . To do this we use the generalized Springer correspondence. We also give a new parametrization of C S ( H ) CS(H) in terms of data coming from bad characteristic.