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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…

Combinatorics · Mathematics 2023-02-15 Oliver Clarke , Akihiro Higashitani , Max Kölbl

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

A lattice polytope is called spanning if its lattice points affinely span the ambient lattice. We show as a corollary to a general result in the Ehrhart theory of lattice polytopes that the $h^*$-vector of a spanning lattice polytope has no…

Combinatorics · Mathematics 2019-10-25 Johannes Hofscheier , Lukas Katthän , Benjamin Nill

For a simplicial complex $\Delta$, the graded Betti number $\beta_{i,j}(k[\Delta])$ of the Stanley-Reisner ring $k[\Delta]$ over a field $k$ has a combinatorial interpretation due to Hochster. Terai and Hibi showed that if $\Delta$ is the…

Combinatorics · Mathematics 2010-04-07 Suyoung Choi , Jang Soo Kim

We present lower bounds for the coefficients of Ehrhart polynomials of convex lattice polytopes in terms of their volume. Concerning the coefficients of the Ehrhart series of a lattice polytope we show that Hibi's lower bound is not true…

Metric Geometry · Mathematics 2008-02-26 Martin Henk , Makoto Tagami

Every $n th$ order monic polynomial corresponds $n$-dimensional vector. If the given polynomial is stable that is all its roots lie in the open left half plane it is said to be Hurwitz polynomial and the corresponding vector is called…

Optimization and Control · Mathematics 2018-10-24 Vakif Dzhafarov , Özlem Esen , Taner Büyükköroğlu

Let $L$ be a distributive lattice and $R[L]$ the associated Hibi ring. We show that if $L$ is planar, then any bounded Hibi subring of $R[L]$ has a quadratic Gr\"obner basis. We characterize all planar distributive lattices $L$ for which…

Commutative Algebra · Mathematics 2019-01-23 Rida Irfan , Nadia Shoukat

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…

Combinatorics · Mathematics 2024-09-24 Matthias Beck , Ellinor Janssen , Katharina Jochemko

Darmon points on p-adic tori and Jacobians of Shimura curves over Q were introduced in previous joint works with Rotger as generalizations of Darmon's Stark-Heegner points. In this article we study the algebraicity over extensions of a real…

Number Theory · Mathematics 2011-05-19 M. Longo , S. Vigni

A $\delta$-vector $\delta(\Pc)= (\delta_0, \delta_1, ..., \delta_d)$ is called shifted symmetric if $\delta_{d-i} = \delta_{i+1}$ for each $0 \leq i \leq [(d-1)/2]$. A natural family of $(0,1)$-polytopes with shifted symmetric…

Combinatorics · Mathematics 2010-01-19 Akihiro Higashitani

Let M be a matroid on E, representable over a field of characteristic zero. We show that h-vectors of the following simplicial complexes are log-concave: 1. The matroid complex of independent subsets of E. 2. The broken circuit complex of…

Combinatorics · Mathematics 2012-07-25 June Huh

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

Let $P_{\lambda\Sigma_n}$ be the Ehrhart polynomial associated to an intergal multiple $\lambda$ of the standard symplex $\Sigma_n \subset \mathbb{R}^n$. In this paper we prove that if $(M, L)$ is an $n$-dimensional polarized toric manifold…

Differential Geometry · Mathematics 2022-06-29 Andrea Loi , Fabio Zuddas

The characterization of lattice polytopes based upon information about their Ehrhart $h^*$-polynomials is a difficult open problem. In this paper, we finish the classification of lattice polytopes whose $h^*$-polynomials satisfy two…

Combinatorics · Mathematics 2015-03-20 Akihiro Higashitani , Benjamin Nill , Akiyoshi Tsuchiya

If $P$ is a lattice polytope (that is, the convex hull of a finite set of lattice points in $\mathbf{R}^n$), then every sum of $h$ lattice points in $P$ is a lattice point in the $h$-fold sumset $hP$. However, a lattice point in the…

Number Theory · Mathematics 2020-04-17 Melvyn B. Nathanson

A polytope is integral if all of its vertices are lattice points. The constant term of the Ehrhart polynomial of an integral polytope is known to be 1. In previous work, we showed that the coefficients of the Ehrhart polynomial of a…

Combinatorics · Mathematics 2009-11-12 Fu Liu

We give a combinatorial proof of a lattice point identity involving a lattice polygon and its dual, generalizing the formula $area(\Delta) + area(\Delta^*) = 6$ for reflexive $\Delta$. The identity is equivalent to the stringy Libgober-Wood…

Combinatorics · Mathematics 2023-09-06 Ulrike Bücking , Christian Haase , Karin Schaller , Jan-Hendrik de Wiljes

Let $\Delta$ be a Delzant polytope in ${\mathbb R}^n$ and ${\mathbf b}\in{\mathbb Z}^n$. Let $E$ denote the symplectic fibration over $S^2$ determined by the pair $(\Delta,\,{\mathbf b})$. Under certain hypotheses, we prove the equivalence…

Symplectic Geometry · Mathematics 2011-08-10 Andrés Viña

A polynomial has saturated Newton polytope (SNP) if every lattice point of the convex hull of its exponent vectors corresponds to a monomial. We compile instances of SNP in algebraic combinatorics (some with proofs, others conjecturally):…

Combinatorics · Mathematics 2019-12-03 Cara Monical , Neriman Tokcan , Alexander Yong

For any root system of rank $r$, we study the "dominant weight polytope" $P^\lambda$ associated with a strongly dominant weight $\lambda$. We prove that $P^\lambda$ is combinatorially equivalent to the $r$-dimensional cube. As an…

Representation Theory · Mathematics 2024-05-07 Gaston Burrull , Tao Gui , Hongsheng Hu