A generalization of Springer theory using nearby cycles
Abstract
Let g be a complex semisimple Lie algebra, and f : g --> g/G the adjoint quotient map. Springer theory of Weyl group representations can be seen as the study of the singularities of f. We give a generalization of Springer theory to visible, polar representations. It is a class of rational representations of complex reductive groups, for which the invariant theory works by analogy with the adjoint representations. Let G|V be such a representation, f : V --> V/G the quotient map, and P the sheaf of nearby cycles of f. We show that the Fourier transform of P is an intersection homology sheaf on V*. Associated to G|V, there is a finite complex reflection group W, called the Weyl group of G|V. We describe the endomorphism ring of P as a deformation of the group algebra of W.
Cite
@article{arxiv.math/9802042,
title = {A generalization of Springer theory using nearby cycles},
author = {Mikhail Grinberg},
journal= {arXiv preprint arXiv:math/9802042},
year = {2009}
}
Comments
28 pages, 1 figure, AMSLaTeX; the paper has been modified to eliminate overlap with math.AG/9805031