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An interesting open problem in Ehrhart theory is to classify those lattice polytopes having a unimodal $h^*$-vector. Although various sufficient conditions have been found, necessary conditions remain a challenge. In this paper, we consider…

Combinatorics · Mathematics 2014-08-28 Benjamin Braun , Robert Davis

Let $\delta(\mathcal{P})$ be the $\delta$-vector of a reflexive polytope $\mathcal{P} \subset \mathbb{R}^d$ of dimension $d$ and $\delta(\mathcal{P} ^\vee)$ the $\delta$-vector of the dual polytope $\mathcal{P}^\vee \subset \mathbb{R}^d$.…

Combinatorics · Mathematics 2020-09-07 Akiyoshi Tsuchiya

For any lattice polytope $P$, we consider an associated polynomial $\bar{\delta}_{P}(t)$ and describe its decomposition into a sum of two polynomials satisfying certain symmetry conditions. As a consequence, we improve upon known…

Combinatorics · Mathematics 2009-09-24 Alan Stapledon

Ehrhart theory is the study of sequences recording the number of integer points in non-negative integral dilates of rational polytopes. For a given lattice polytope, this sequence is encoded in a finite vector called the Ehrhart…

Combinatorics · Mathematics 2017-11-30 Benjamin Braun

In this paper, we investigate two properties concerning the unimodality of the $\delta$-vectors of lattice polytopes, which are log-concavity and alternatingly increasingness. For lattice polytopes $\mathcal{P}$ of dimension $d$, we prove…

Combinatorics · Mathematics 2015-04-17 Akihiro Higashitani

We introduce the notion of a weighted $\delta$-vector of a lattice polytope. Although the definition is motivated by motivic integration, we study weighted $\delta$-vectors from a combinatorial perspective. We present a version of Ehrhart…

Combinatorics · Mathematics 2009-07-10 Alan Stapledon

Starting from any finite simple graph, one can build a reflexive polytope known as a symmetric edge polytope. The first goal of this paper is to show that symmetric edge polytopes are intrinsically matroidal objects: more precisely, we…

Combinatorics · Mathematics 2023-07-12 Alessio D'Alì , Martina Juhnke-Kubitzke , Melissa Koch

For a given lattice polytope, two fundamental problems within the field of Ehrhart theory are to (1) determine if its (Ehrhart) $h^\ast$-polynomial is unimodal and (2) to determine if its Ehrhart polynomial has only positive coefficients.…

Combinatorics · Mathematics 2018-04-24 Fu Liu , Liam Solus

A classification of discrete polymatroids whose independence polytopes are reflexive will be presented.

Combinatorics · Mathematics 2023-02-27 Jürgen Herzog , Takayuki Hibi

We show that the Ehrhart h-vector of an integer Gorenstein polytope with a regular unimodular triangulation satisfies McMullen's g-theorem; in particular, it is unimodal. This result generalizes a recent theorem of Athanasiadis (conjectured…

Commutative Algebra · Mathematics 2021-05-18 Winfried Bruns , Tim Roemer

A long-standing open conjecture in combinatorics asserts that a Gorenstein lattice polytope with the integer decomposition property (IDP) has a unimodal (Ehrhart) $h^\ast$-polynomial. This conjecture can be viewed as a strengthening of a…

Combinatorics · Mathematics 2018-06-04 Benjamin Braun , Robert Davis , Liam Solus

It is known that every lattice polytope is unimodularly equivalent to a face of some reflexive polytope. A stronger question is to ask whether every $(0,1)$-polytope is unimodularly equivalent to a facet of some reflexive polytope. A large…

Combinatorics · Mathematics 2020-09-08 Takahiro Nagaoka , Akiyoshi Tsuchiya

Lattice polytopes are called IDP polytopes if they have the integer decomposition property, i.e., any lattice point in a $k$th dilation is a sum of $k$ lattice points in the polytope. It is a long-standing conjecture whether the numerator…

Combinatorics · Mathematics 2025-05-27 Johannes Hofscheier , Vadym Kurylenko , Benjamin Nill

Unimodular triangulations of lattice polytopes arise in algebraic geometry, commutative algebra, integer programming and, of course, combinatorics. In this article, we review several classes of polytopes that do have unimodular…

Combinatorics · Mathematics 2021-09-10 Christian Haase , Andreas Paffenholz , Lindsay C. Piechnik , Francisco Santos

We produce the first regular unimodular triangulation of an arbitrary matroid base polytope. We then extend our triangulation to integral generalized permutahedra. Prior to this work it was unknown whether each matroid base polytope…

Combinatorics · Mathematics 2024-04-05 Spencer Backman , Gaku Liu

We study the Ehrhart theory of quadratic irrational polytopes that undergo vector dilations. That is, for a given polytope with vertices in $\mathbb{Q}(\sqrt{D})$, and a different dilation factor for each facet, we show that the leading…

Number Theory · Mathematics 2018-10-03 Yashaswika Gaur , Tian An Wong

A lattice polytope $\mathcal{P}$ is called reflexive if its dual $\mathcal{P}^\vee$ is a lattice polytope. The property that $\mathcal{P}$ is unimodularly equivalent to $\mathcal{P}^\vee$ does not hold in general, and in fact there are few…

Combinatorics · Mathematics 2017-11-21 Takayuki Hibi , McCabe Olsen , Akiyoshi Tsuchiya

We consider unimodality and related properties of f-vectors of polytopes in various dimensions. By a result of Kalai (1988), f-vectors of 5-polytopes are unimodal. In higher dimensions much less can be said; we give an overview on current…

Combinatorics · Mathematics 2007-05-23 Axel Werner

We call the $\delta$-vector of an integral convex polytope of dimension $d$ flat if the $\delta$-vector is of the form $(1,0,\ldots,0,a,\ldots,a,0,\ldots,0)$, where $a \geq 1$. In this paper, we give the complete characterization of…

Combinatorics · Mathematics 2020-09-08 Takayuki Hibi , Akiyoshi Tsuchiya

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
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