English

The B-orbits on a Hermitian symmetric variety in characteristic 2

Algebraic Geometry 2021-07-23 v2 Combinatorics Representation Theory

Abstract

Let GG be a reductive linear algebraic group over an algebraically closed field K\mathbb{K} of characteristic 22. Fix a parabolic subgroup PP such that the corresponding parabolic subgroup over C\mathbb{C} has abelian unipotent radical and fix a Levi subgroup LPL\subseteq P. We parametrize the orbits of a Borel BPB\subseteq P over the Hermitian symmetric variety G/LG/L supposing the root system Φ\Phi is irreducible. For Φ\Phi simply laced we prove a combinatorial characterization of the Bruhat order over these orbits. We also prove a formula to compute the dimension of the orbits from combinatorial characteristics of their representatives.

Keywords

Cite

@article{arxiv.2104.07315,
  title  = {The B-orbits on a Hermitian symmetric variety in characteristic 2},
  author = {Michele Carmassi},
  journal= {arXiv preprint arXiv:2104.07315},
  year   = {2021}
}