English

Hypersimplices are Ehrhart Positive

Combinatorics 2020-11-23 v2

Abstract

We consider the Ehrhart polynomial of hypersimplices. It is proved that these polynomials have positive coefficients and we give a combinatorial formula for each of them. This settles a problem posed by Stanley and also proves that uniform matroids are Ehrhart positive, an important and yet unsolved particular case of a conjecture posed by De Loera et al. To this end, we introduce a new family of numbers that we call weighted Lah numbers and study some of their properties.

Keywords

Cite

@article{arxiv.1911.10146,
  title  = {Hypersimplices are Ehrhart Positive},
  author = {Luis Ferroni},
  journal= {arXiv preprint arXiv:1911.10146},
  year   = {2020}
}

Comments

10 pages, 2 tables

R2 v1 2026-06-23T12:24:44.418Z