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Perfect graphs form one of the distinguished classes of finite simple graphs. In 2006, Chudnovsky, Robertson, Seymour and Thomas proved that a graph is perfect if and only if it has no odd holes and no odd antiholes as induced subgraphs,…

Commutative Algebra · Mathematics 2023-07-14 Hidefumi Ohsugi , Kazuki Shibata , Akiyoshi Tsuchiya

Symmetric edge polytopes are a recent and well-studied family of centrally symmetric polytopes arising from graphs. In this paper, we introduce a generalization of this family to arbitrary simplicial complexes. We show how topological…

Combinatorics · Mathematics 2026-02-20 Torben Donzelmann , Thiago Holleben , Martina Juhnke

We define the (dynamical) core of a topological polynomial (and the associated lamination). This notion extends that of the core of a unimodal interval map. Two explicit descriptions of the core are given: one related to periodic objects…

Dynamical Systems · Mathematics 2016-01-18 Alexander Blokh , Lex Oversteegen , Ross Ptacek , Vladlen Timorin

We give an explicit and simple construction of the incidence graph for the integral cohomology of real Grassmann manifold Gr(k,n) in terms of the Young diagrams filled with the letter q in checkered pattern. It turns out that there are two…

Algebraic Geometry · Mathematics 2013-09-24 Luis Casian , Yuji Kodama

A bipartite graph is chordal bipartite if every cycle of length at least six has a chord in it. M$\ddot{\rm u}$ller \cite {muller1996Hamiltonian} has shown that the Hamiltonian cycle problem is NP-complete on chordal bipartite graphs by…

Discrete Mathematics · Computer Science 2021-07-13 S. Aadhavan , R. Mahendra Kumar , P. Renjith , N. Sadagopan

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

We introduce the concept of a Gr\"obner nice pair of ideals in a polynomial ring and we present some applications.

Commutative Algebra · Mathematics 2021-01-22 Mircea Cimpoeaş , Dumitru I. Stamate

In a recent paper, Beniamini and Nisan gave a closed-form formula for the unique multilinear polynomial for the Boolean function determining whether a given bipartite graph $G \subseteq K_{n,n}$ has a perfect matching, together with an…

Discrete Mathematics · Computer Science 2020-03-26 Thorben Tröbst , Vijay V. Vazirani

We say that finite groups are isospectral if they have the same sets of orders of elements. It is known that every nonsolvable finite group $G$ isospectral to a finite simple group has a unique nonabelian composition factor, that is, the…

Group Theory · Mathematics 2022-07-07 Maria A. Grechkoseeva , Andrey V. Vasil'ev

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

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 study the class of 1-perfectly orientable graphs, that is, graphs having an orientation in which every out-neighborhood induces a tournament. 1-perfectly orientable graphs form a common generalization of chordal graphs and circular arc…

Combinatorics · Mathematics 2016-03-08 Tatiana Romina Hartinger , Martin Milanič

In this paper we prove the existence of a special order on the set of minimal monomial generators of powers of edge ideals of arbitrary graphs. Using this order we find new upper bounds on the regularity of powers of edge ideals of graphs…

Commutative Algebra · Mathematics 2014-06-03 Arindam Banerjee

Let $G$ be a finite simple graph and $I(G)$ denote the corresponding edge ideal. In this paper we prove that if $G$ is a very well-covered graph then for all $s \geq 2$ the regularity of $I(G)^s$ is exactly $2s+\nu(G)-1$.

Commutative Algebra · Mathematics 2019-01-03 A V Jayanthan , S Selvaraja

Let $e$ be a positive integer, $p$ be an odd prime, $q=p^{e}$, and $\Bbb F_q$ be the finite field of $q$ elements. Let $f,g \in \Bbb F_q [X,Y]$. The graph $G=G_q(f,g)$ is a bipartite graph with vertex partitions $P=\Bbb F_q^3$ and $L=\Bbb…

Combinatorics · Mathematics 2015-07-21 Xiang-dong Hou , Stephen D. Lappano , Felix Lazebnik

This extended abstract gives a construction for lifting a Gr\"obner basis algorithm for an ideal in a polynomial ring over a commutative ring R under the condition that R also admits a Gr\"obner basis for every ideal in R.

Commutative Algebra · Mathematics 2023-06-19 Deepak Kapur , Paliath Narendran

We study a symmetry problem for the $h$-polynomials of edge rings of bipartite graphs. Let $G$ be a bipartite graph and write $h(\mathbb{k}[G];t)=h_0+h_1t+\cdots+h_st^s$. We prove that if $\Bbbk[G]$ is pseudo-Gorenstein and $h_1=h_{s-1}$,…

Commutative Algebra · Mathematics 2026-05-28 Yuta Hatasa

In his Ph.D. thesis, Sean Griffin introduced a family of ideals and found monomial bases for their quotient rings. These rings simultaneously generalize the Delta Conjecture coinvariant rings of Haglund-Rhoades-Shimozono and the cohomology…

Combinatorics · Mathematics 2023-08-01 Tianyi Yu

We study a family $\mathcal{B}$ of pseudo-multipartite graphs indexed by staircase partitions. They are realised from the reduced words of certain class of permutations. We investigate the vertex proper colouring of these graphs and give…

Combinatorics · Mathematics 2023-10-27 Praise Adeyemo

We will study monomial ideals $I$ in the exterior algebra as well as in the polynomial ring whose generic initial ideal is constant for all term orders up to permutations of variables. First, in the exterior algebra, we determine all graphs…

Commutative Algebra · Mathematics 2007-05-23 Satoshi Murai