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Related papers: Stanley's non-Ehrhart-positive order polytopes

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Stanley introduced and studied two lattice polytopes, the order polytope and chain polytope, associated to a finite poset. Recently Ohsugi and Tsuchiya introduce an enriched version of them, called the enriched order polytope and enriched…

Combinatorics · Mathematics 2024-03-08 Soichi Okada , Akiyoshi Tsuchiya

The cosmological polytope of a graph $G$ was recently introduced to give a geometric approach to the computation of wavefunctions for cosmological models with associated Feynman diagram $G$. Basic results in the theory of positive…

Combinatorics · Mathematics 2025-01-09 Justus Bruckamp , Lina Goltermann , Martina Juhnke , Erik Landin , Liam Solus

Counting lattice points and triangulating polytopes is a prominent subject in discrete geometry, yet proving Ehrhart positivity or existence of unimodular triangulations remain of utmost difficulty in general, even for ``easy'' simplices.…

Combinatorics · Mathematics 2025-12-22 Jhon B. Caicedo , Martina Juhnke , Germain Poullot

We show that the polytopes obtained from the Birkhoff polytope by imposing additional inequalities restricting the "longest increasing subsequence" have Ehrhart quasi-polynomials which are honest polynomials, even though they are just…

Combinatorics · Mathematics 2023-12-21 Per Alexandersson , Sam Hopkins , Gjergji Zaimi

An orthant polyhedron is a polyhedron with $m$ hyperfaces, that could be realized as a section of the $m$-dimensional non-negative orthant. We classify all 2-dimensional orthant polyhedra and provide some partial results towards the…

Metric Geometry · Mathematics 2014-07-23 Nikolay Pechenkin

We introduce several classes of polytopes contained in $[0,1]^n$ and cut out by inequalities involving sums of consecutive coordinates. We show that the normalized volumes of these polytopes enumerate circular extensions of certain partial…

Combinatorics · Mathematics 2020-07-10 Arvind Ayyer , Matthieu Josuat-Vergès , Sanjay Ramassamy

We establish a connection between the orbifold cohomology of hypertoric varieties and the Ehrhart theory of Lawrence polytopes. More specifically, we show that the dimensions of the orbifold cohomology groups of a hypertoric variety are…

Combinatorics · Mathematics 2009-09-24 Alan Stapledon

The order and chain polytopes, introduced by Richard P. Stanley, form a pair of Ehrhart equivalent polytopes associated to a given finite poset. A conjecture by Takayuki Hibi and Nan Li states that the $f$-vector of the chain polytope…

Combinatorics · Mathematics 2026-04-14 Ibrahim Ahmad , Ghislain Fourier , Michael Joswig

In [Problems on polytopes, their groups, and realizations, Periodica Math. Hungarica 53 (2006) 231-255] Schulte and Weiss proposed the following problem: {\em Characterize regular polytopes of orders $2^np$ for $n$ a positive integer and…

Combinatorics · Mathematics 2024-07-16 Dong-Dong Hou , Yan-Quan Feng , Dimitri Leemans

We conduct a systematic study of the Ehrhart theory of certain slices of rectangular prisms. Our polytopes are generalizations of the hypersimplex and are contained in the larger class of polypositroids introduced by Lam and Postnikov;…

Combinatorics · Mathematics 2025-04-30 Luis Ferroni , Daniel McGinnis

Let P be a convex polytope containing the origin, whose dual is a lattice polytope. Hibi's Palindromic Theorem tells us that if P is also a lattice polytope then the Ehrhart $\delta$-vector of P is palindromic. Perhaps less well-known is…

Combinatorics · Mathematics 2022-10-28 Matthew H. J. Fiset , Alexander M. Kasprzyk

There is a simple formula for the Ehrhart polynomial of a cyclic polytope. The purpose of this paper is to show that the same formula holds for a more general class of polytopes, lattice-face polytopes. We develop a way of decomposing any…

Combinatorics · Mathematics 2007-05-23 Fu Liu

The h^*-polynomial of a lattice polytope is the numerator of the generating function of the Ehrhart polynomial. Let P be a lattice polytope with h^*-polynomial of degree d and with linear coefficient h^*_1. We show that P has to be a…

Combinatorics · Mathematics 2008-09-29 Benjamin Nill

In the last decade, the order polytope of the zigzag poset has been thoroughly studied. A related poset, called \emph{crown poset}, obtained by adding an extra relation between the endpoints of an even zigzag poset, is not so well…

Combinatorics · Mathematics 2025-12-10 Teemu Lundström , Leonardo Saud Maia Leite

A half-integral polygon with quasi-period collapse behaves similarly to a lattice polygon in the sense that the number of lattice points in its integer dilates can be calculated as values of a polynomial, its Ehrhart polynomial. As a main…

Combinatorics · Mathematics 2025-07-03 Martin Bohnert

The Ehrhart quasipolynomial of a rational polytope $\mathsf{P}$ encodes fundamental arithmetic data of $\mathsf{P}$, namely, the number of integer lattice points in positive integral dilates of $\mathsf{P}$. Ehrhart quasipolynomials were…

Combinatorics · Mathematics 2023-08-29 Matthias Beck , Sophia Elia , Sophie Rehberg

If $P$ is a lattice polytope (i.e., $P$ is the convex hull of finitely many integer points in $\mathbb{R}^d$) of dimension $d$, Ehrhart's famous theorem (1962) asserts that the integer-point counting function $|nP \cap \mathbb{Z}^d|$ is a…

Combinatorics · Mathematics 2024-09-24 Esme Bajo , Matthias Beck

Preorder polytopes, defined from preorders on finite sets, are introduced and studied from a lattice point enumeration point of view. They naturally generalize arbor polytopes, recently introduced and studied by the second named author.…

Combinatorics · Mathematics 2026-05-27 Frédéric Chapoton , Christos A. Athanasiadis

The Ehrhart ring of the edge polytope $\mathcal{P}_G$ for a connected simple graph $G$ is known to coincide with the edge ring of the same graph if $G$ satisfies the odd cycle condition. This paper gives for a graph which does not satisfy…

Combinatorics · Mathematics 2011-05-26 Tetsushi Matsui

There is a well-established dictionary between zonotopes, hyperplane arrangements, and their (oriented) matroids. Arguably one of the most famous examples is the class of graphical zonotopes, also called acyclotopes, which encode…

Combinatorics · Mathematics 2024-09-24 Eleonore Bach , Matthias Beck , Sophie Rehberg
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