Calculations with graded perverse-coherent sheaves
Representation Theory
2019-03-11 v2
Abstract
In this paper, we carry out several computations involving graded (or -equivariant) perverse-coherent sheaves on the nilpotent cone of a reductive group in good characteristic. In the first part of the paper, we compute the weight of the -action on certain normalized (or "canonical") simple objects, confirming an old prediction of Ostrik. In the second part of the paper, we explicitly describe all simple perverse coherent sheaves for , in every characteristic other than 2 or 3. Applications include an explicit description of the cohomology of tilting modules for the corresponding quantum group, as well as a proof that never admits a positive grading when the characteristic of the field is greater than 3.
Cite
@article{arxiv.1806.07780,
title = {Calculations with graded perverse-coherent sheaves},
author = {Pramod N. Achar and William D. Hardesty},
journal= {arXiv preprint arXiv:1806.07780},
year = {2019}
}
Comments
23 pages. v2: minor corrections