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The Ehrhart polynomial $ehr_P (n)$ of a lattice polytope $P$ gives the number of integer lattice points in the $n$-th dilate of $P$ for all integers $n\geq 0$. The degree of $P$ is defined as the degree of its $h^\ast$-polynomial, a…

组合数学 · 数学 2024-09-24 Matthias Beck , Ellinor Janssen , Katharina Jochemko

To every poset P, Stanley (1986) associated two polytopes, the order polytope and the chain polytope, whose geometric properties reflect the combinatorial qualities of P. This construction allows for deep insights into combinatorics by way…

组合数学 · 数学 2017-05-08 Thomas Chappell , Tobias Friedl , Raman Sanyal

We study the equivariant Ehrhart theory of families of polytopes that are invariant under a non-trivial action of the group with order two. We study families of polytopes whose equivariant $H^*$-polynomial both succeed and fail to be…

组合数学 · 数学 2023-02-15 Oliver Clarke , Akihiro Higashitani , Max Kölbl

We prove the unimodality of the Ehrhart $\delta$-polynomial of the chain polytope of the zig-zag poset, which was conjectured by Kirillov. First, based on a result due to Stanley, we show that this polynomial coincides with the…

组合数学 · 数学 2016-03-29 Herman Z. Q. Chen , Philip B. Zhang

Over a decade ago De Loera, Haws and K\"oppe conjectured that Ehrhart polynomials of matroid polytopes have only positive coefficients and that the coefficients of the corresponding $h^*$-polynomials form a unimodal sequence. The first of…

组合数学 · 数学 2022-08-05 Luis Ferroni , Katharina Jochemko , Benjamin Schröter

We introduce a class of polytopes that we call chainlink polytopes and which allow us to construct infinite families of pairs of non isomorphic rational polytopes with the same Ehrhart quasi-polynomial. Our construction is based on circular…

组合数学 · 数学 2025-04-08 Ezgi Kantarcı Oğuz , Cem Yalım Özel , Mohan Ravichandran

Given a pair of finite posets $A \subseteq P$, the function counting integer-valued order preserving extensions of an order preserving map $\lambda : A\rightarrow \mathbb{Z}$ from $A$ to $P$ is given by a piecewise polynomial in $\lambda$.…

组合数学 · 数学 2026-04-20 Katharina Jochemko , Krishna Menon

In this paper we investigate the number of integer points lying in dilations of lattice path matroid polytopes. We give a characterization of such points as polygonal paths in the diagram of the lattice path matroid. Furthermore, we prove…

The present work investigates regular, semiregular, and chiral polytopes of any rank $d\geq 3$, whose automorphism groups are 2-groups. There is a large variety of rather small finite regular or alternating semiregular polytopes with…

群论 · 数学 2025-12-18 Gabriel Cunningham , Yan-Quan Feng , Dong-Dong Hou , Egon Schulte

We analyze marked poset polytopes and generalize a result due to Hibi and Li, answering whether the marked chain polytope is unimodular equivalent to the marked order polytope. Both polytopes appear naturally in the representation theory of…

组合数学 · 数学 2015-07-06 Ghislain Fourier

Stanley introduced in 1986 the order polytope and the chain polytope for a given finite poset. These polytopes contain much information about the poset and have given rise to important examples in polyhedral geometry. In 1993, Reiner…

组合数学 · 数学 2023-11-09 Matthias Beck , Max Hlavacek

In this paper, we provide an overview of Ehrhart polynomials associated with order polytopes of finite posets, a concept first introduced by Stanley. We focus on their combinatorial interpretations for many sequences listed on the OEIS. We…

组合数学 · 数学 2024-12-30 Feihu Liu , Guoce Xin , Chen Zhang

Matroids give rise to several natural constructions of polytopes. Inspired by this, we examine polytopes that arise from the signed circuits of an oriented matroid. We give the dimensions of these polytopes arising from graphical oriented…

组合数学 · 数学 2025-01-03 Laura Escobar , Jodi McWhirter

In this short note, we give large counterexamples to natural questions about certain order polytopes, in particular, Gelfand--Tsetlin polytopes. Several of the counterexamples are too large to be discovered via a brute-force computer…

组合数学 · 数学 2018-09-26 Per Alexandersson

It is known that the Ehrhart polynomials of cross-polytopes, as well as of pyramids over them, have positive coefficients. We give a combinatorial proof of this fact by showing that a scaled version of the Ehrhart polynomials are generating…

组合数学 · 数学 2025-12-10 Krishna Menon , Emil Verkama

Abstract polytopes are a combinatorial generalization of convex and skeletal polytopes. Counting how many flag orbits a polytope has under its automorphism group is a way of measuring how symmetric it is. Polytopes with one flag orbit are…

组合数学 · 数学 2024-02-20 Elías Mochán

Stanley introduced two classes of lattice polytopes associated to posets, which are called the order polytope ${\mathcal O}_P$ and the chain polytope ${\mathcal C}_P$ of a poset $P$. It is known that, given a poset $P$, the Ehrhart…

组合数学 · 数学 2022-01-26 Hidefumi Ohsugi , Akiyoshi Tsuchiya

We study restricted chain-order polytopes associated to Young diagrams using combinatorial mutations. These polytopes are obtained by intersecting chain-order polytopes with certain hyperplanes. The family of chain-order polytopes…

组合数学 · 数学 2022-11-16 Oliver Clarke , Akihiro Higashitani , Francesca Zaffalon

In 1986 Stanley associated to a poset the order polytope. The close interplay between its combinatorial and geometric properties makes the order polytope an object of tremendous interest. Double posets were introduced in 2011 by Malvenuto…

组合数学 · 数学 2022-09-15 Aenne Benjes

The Ehrhart polynomial of a lattice polygon P is completely determined by the pair (b(P),i(P)) where b(P) equals the number of lattice points on the boundary and i(P) equals the number of interior lattice points. All possible pairs…

组合数学 · 数学 2020-02-11 Johannes Hofscheier , Benjamin Nill , Dennis Öberg