English

Harmonics and graded Ehrhart theory

Combinatorics 2024-09-25 v3 Commutative Algebra

Abstract

The Ehrhart polynomial and Ehrhart series count lattice points in integer dilations of a lattice polytope. We introduce and study a qq-deformation of the Ehrhart series, based on the notions of harmonic spaces and Macaulay's inverse systems for coordinate rings of finite point configurations. We conjecture that this qq-Ehrhart series is a rational function, and introduce and study a bigraded algebra whose Hilbert series matches the qq-Ehrhart series. Defining this algebra requires a new result on Macaulay inverse systems for Minkowski sums of point configurations.

Keywords

Cite

@article{arxiv.2407.06511,
  title  = {Harmonics and graded Ehrhart theory},
  author = {Victor Reiner and Brendon Rhoades},
  journal= {arXiv preprint arXiv:2407.06511},
  year   = {2024}
}

Comments

61 pages. Version 3: This version features a streamlined proof of Theorem 1.4, based on a suggestion of Ian Cavey

R2 v1 2026-06-28T17:33:47.509Z