Jordan classes and Lusztig strata in disconnected reductive groups

Abstract

Let $G$ be a non-connected reductive algebraic group over an algebraically closed field $\mathbb{K}$ and let $D$ be a connected component of $G$. We investigate Jordan classes of $D$ and we obtain a description of the regular part of the closure of a Jordan class in terms of induction of $G^{\circ }$-orbits. We use this result to show that Lusztig strata in a non-connected reductive algebraic group are locally closed.