Intersection cohomology of Popov-Vinberg varieties

Abstract

The Popov-Vinberg variety of a simply connected, split, semisimple algebraic group $G$ is a singular affine variety that contains the basic affine space $G/U$ as a Zariski open subset. It is defined as the spectrum of the ring of functions on $G/U$, and can also be identified with the universal symplectic implosion for the maximal compact subgroup of $G$. We provide a recursive procedure for computing the intersection cohomology of this variety, with an emphasis on the case where $G={\mathrm{SL}}_n$.

Various minor edits. Final version, to appear in Transformation Groups