Cominuscule points and Schubert varieties
Algebraic Geometry
2020-02-07 v2 Combinatorics
Representation Theory
Abstract
We introduce the notion of a cominuscule point in a Schubert variety in a generalized flag variety for a semisimple group. We derive formulas expressing the Hilbert series and multiplicity of a Schubert variety at a cominuscule point in terms of the restrictions of classes in torus-equivariant K-theory and cohomology to that point, generalizing previously known formulas for flag varieties of cominuscule type. Thus, we can calculate Hilbert series and multiplicities in cases where these were previously unknown. The formulas for Schubert varieties are special cases of more general formulas valid at generalized cominuscule points of schemes with torus actions.
Cite
@article{arxiv.1701.05956,
title = {Cominuscule points and Schubert varieties},
author = {William Graham and Victor Kreiman},
journal= {arXiv preprint arXiv:1701.05956},
year = {2020}
}
Comments
25 pages; v2: shortened