English

The Ehrhart $h^*$-polynomials of positroid polytopes

Combinatorics 2025-01-20 v3

Abstract

A positroid is a matroid realized by a matrix such that all maximal minors are non-negative. Positroid polytopes are matroid polytopes of positroids. In particular, they are lattice polytopes. The Ehrhart polynomial of a lattice polytope counts the number of integer points in the dilation of that polytope. The Ehrhart series is the generating function of the Ehrhart polynomial, a rational function with a numerator called the hh^*-polynomial. We give explicit formulas for the hh^*-polynomials of an arbitrary positroid polytope regarding permutation descents. Our result generalizes that of Early, Kim, and Li for hypersimplices.

Keywords

Cite

@article{arxiv.2410.01743,
  title  = {The Ehrhart $h^*$-polynomials of positroid polytopes},
  author = {Yuhan Jiang},
  journal= {arXiv preprint arXiv:2410.01743},
  year   = {2025}
}

Comments

arXiv admin note: text overlap with arXiv:2404.03026 by other authors

R2 v1 2026-06-28T19:05:36.059Z