Delta-matroids and toric degenerations in OG(n,2n+1)
Algebraic Geometry
2025-08-19 v2 Combinatorics
Abstract
We construct an explicit, embedded degeneration of the general torus orbit closure in the maximal orthogonal Grassmannian OG(n,2n+1) into a union of Richardson varieties. In particular, we deduce a formula for the cohomology class of the torus orbit closure, as a sum of products of Schubert classes. The moment map images of the degenerate pieces are the base polytopes of their underlying delta-matroids, and give a polyhedral decomposition of the unit hypercube, which had previously been studied by Chen-Sanchez-Veliz-Ying.
Keywords
Cite
@article{arxiv.2507.16133,
title = {Delta-matroids and toric degenerations in OG(n,2n+1)},
author = {Chen Chen and Carl Lian},
journal= {arXiv preprint arXiv:2507.16133},
year = {2025}
}
Comments
Minor changes. Name of first-named author changed (refers to same person)