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We determine a Groebner basis for the secant ideal of the toric ideal associated to the second hypersimplex, with respect to any circular term order. The Groebner basis of the secant ideal requires polynomials of odd degree up to n. This…

Commutative Algebra · Mathematics 2008-12-10 Seth Sullivant

We consider arrangements of tropical hyperplanes where the apices of the hyperplanes are taken to infinity in certain directions. Such an arrangement defines a decomposition of Euclidean space where a cell is determined by its `type' data,…

Commutative Algebra · Mathematics 2025-02-21 Ayah Almousa , Anton Dochtermann , Ben Smith

The type A_n full root polytope is the convex hull in R^{n+1} of the origin and the points e_i-e_j for 1<= i<j <= n+1. Given a tree T on the vertex set [n+1], the associated root polytope P(T) is the intersection of the full root polytope…

Combinatorics · Mathematics 2009-09-02 Karola Meszaros

The geometric vertex decomposability property for polynomial ideals is an ideal-theoretic generalization of the vertex decomposability property for simplicial complexes. Indeed, a homogeneous geometrically vertex decomposable ideal is…

Commutative Algebra · Mathematics 2025-11-14 Mike Cummings , Sergio Da Silva , Jenna Rajchgot , Adam Van Tuyl

We describe a generating set for the initial ideal of simplicial toric ideals with respect to the graded reverse lexicographic order, using representations of elements of affine monoids as sums of irreducible elements. Although the…

Commutative Algebra · Mathematics 2026-03-10 Ryotaro Hanyu

We introduce a collection of convex polytopes associated to a torus-equivariant vector bundle on a smooth complete toric variety. We show that the lattice points in these polytopes correspond to generators for the space of global sections…

Algebraic Geometry · Mathematics 2019-02-08 Sandra Di Rocco , Kelly Jabbusch , Gregory G. Smith

A $k$-orbit maniplex is one that has $k$ orbits of flags under the action of its automorphism group. In this paper we extend the notion of symmetry type graphs of maps to that of maniplexes and polytopes and make use of them to study…

Combinatorics · Mathematics 2013-06-10 Gabe Cunningham , Maria del Rio Francos , Isabel Hubard , Micael Toledo

We show that every non-degenerate regular polytope can be used to construct a thin, residually-connected, chamber-transitive incidence geometry, i.e. a regular hypertope, with a tail-triangle Coxeter diagram. We discuss several interesting…

Combinatorics · Mathematics 2020-01-31 Antonio Montero , Asia Ivić Weiss

Two correspondences have been provided that associate any linear code over a finite field with a binomial ideal. In this paper, algorithms for computing their Graver bases and universal Gr\"obner bases are given. To this end, a connection…

Commutative Algebra · Mathematics 2014-05-08 Natalia Dück , Karl-Heinz Zimmermann

We characterize the graphs $G$ for which their toric ideals $I_G$ are complete intersections. In particular we prove that for a connected graph $G$ such that $I_G$ is complete intersection all of its blocks are bipartite except of at most…

Commutative Algebra · Mathematics 2011-10-06 Christos Tatakis , Apostolos Thoma

A toric ideal is called robust if its universal Gr\"obner basis is a minimal set of generators, and is called generalized robust if its universal Gr\"obner basis equals its universal Markov basis (the union of all its minimal sets of…

Commutative Algebra · Mathematics 2022-04-29 Christos Tatakis , Ignacio García-Marco

In this paper, we study toric ideals associated with multichains of posets. It is shown that the comparability graph of a poset is chordal if and only if there exists a quadratic Gr\"obner basis of the toric ideal of the poset. Strong…

Combinatorics · Mathematics 2018-09-03 Hidefumi Ohsugi , Takayuki Hibi

It is known that we can always 3-triangulate (i.e. divide into tetrahedra) convex polyhedra but not always non-convex ones. Polyhedra topologically equivalent to sphere with $p$ handles, shortly $p$-toroids, could not be convex. So, it is…

Metric Geometry · Mathematics 2019-02-08 Milica Stojanović

For an infinite family of monogenic trinomials $P(X) = X^3\pm 3rbX-b$ in $\mathbb{Z}\lbrack X\rbrack$, arithmetical invariants of the cubic number field $L = \mathbb{Q}(\theta)$, generated by a zero $\theta$ of $P(X)$, and of its Galois…

Number Theory · Mathematics 2022-04-12 Daniel C. Mayer , Abderazak Soullami

Given a finite, simple, vertex-weighted graph, we construct a graded associative (non-commutative) algebra, whose generators correspond to vertices and whose ideal of relations has generators that are graded commutators corresponding to…

Algebraic Topology · Mathematics 2012-06-13 Peter Bubenik , Leah H. Gold

In this paper, we prove an analogue of Corr\'adi and Hajnal's classical theorem. There exists $n_0$ such that for every $n \in 3\mathbb{Z}$ when $n \ge n_0$ the following holds. If $G$ is an oriented graph on $n$ vertices and every vertex…

Combinatorics · Mathematics 2017-01-11 József Balogh , Allan Lo , Theodore Molla

There exists just one regular polytope of rank larger than 3 whose full automorphism group is a projective general linear group PGL_2(q), for some prime-power q. This polytope is the 4-simplex and the corresponding group is PGL_2(5), which…

Combinatorics · Mathematics 2009-09-11 Dimitri Leemans , Egon Schulte

Reflexive polytopes form one of the distinguished classes of lattice polytopes. Especially reflexive polytopes which possess the integer decomposition property are of interest. In the present paper, by virtue of the algebraic technique on…

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

In this paper we use toric geometry to investigate the topology of the totally non-negative part of the Grassmannian (Gr_{kn})_{\geq 0}. This is a cell complex whose cells Delta_G can be parameterized in terms of the combinatorics of…

Algebraic Geometry · Mathematics 2008-10-15 Alexander Postnikov , David Speyer , Lauren Williams

We give a classification of finite groups of symplectic birational automorphisms on a manifold of K3^[3]-type with stable and stably saturated cohomological action. We describe the group of polarized automorphisms of a smooth double…

Algebraic Geometry · Mathematics 2024-12-30 Simone Billi , Stevell Muller , Tomasz Wawak