{ "id": "2410.01743", "version": "v2", "published": "2024-10-02T16:54:01.000Z", "updated": "2024-11-24T12:25:28.000Z", "title": "The Ehrhart $h^*$-polynomials of positroid polytopes", "authors": [ "Yuhan Jiang" ], "comment": "20 pages, 10 figures. arXiv admin note: text overlap with arXiv:2404.03026 by other authors", "categories": [ "math.CO" ], "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 $h*$-polynomial. We give explicit formulas for the $h^*$-polynomials of an arbitrary positroid polytope regarding permutation descents. We also compute the $h^*$-polynomial of any positroid polytope with some facets removed and relate it to the descents of permutations. Our result generalizes that of Early, Kim, and Li for hypersimplices.", "revisions": [ { "version": "v2", "updated": "2024-11-24T12:25:28.000Z" } ], "analyses": { "keywords": [ "ehrhart polynomial", "arbitrary positroid polytope regarding permutation", "positroid polytope regarding permutation descents", "lattice polytope counts", "result generalizes" ], "note": { "typesetting": "TeX", "pages": 20, "language": "en", "license": "arXiv", "status": "editable" } } }