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Related papers: Regularity of parity binomial edge ideals

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When $I$ is the edge ideal of a graph $G$, we use combinatorial properities, particularly Property $P$ on connectivity of neighbors of an edge, to classify when a binomial sum of vertices is a regular element on $R/I(G)$. Under a mild…

Commutative Algebra · Mathematics 2024-12-16 Joseph Brennan , Susan Morey

Let $G$ be a finite simple connected graph on $[n]$ and $R = K[x_1, \ldots, x_n]$ the polynomial ring in $n$ variables over a field $K$. The edge ideal of $G$ is the ideal $I(G)$ of $R$ which is generated by those monomials $x_ix_j$ for…

Commutative Algebra · Mathematics 2020-08-13 Takayuki Hibi , Hiroju Kanno , Kyouko Kimura , Kazunori Matsuda , Adam Van Tuyl

We study minimal reductions of edge ideals of graphs and determine restrictions on the coefficients of the generators of these minimal reductions. We prove that when $I$ is not basic, then $\core{I}\subset \m I$, where $I$ is an edge ideal…

Commutative Algebra · Mathematics 2012-05-01 Louiza Fouli , Susan Morey

This paper analyzes the cohomological dimension of the generalized binomial edge ideal $\calJ_{K_m,G}$ for a complete $r$-partite graph $G$. Additionally, the Krull dimension, the depth, the Castelnuovo--Mumford regularity, the Hilbert…

Commutative Algebra · Mathematics 2023-12-20 Yi-Huang Shen , Guangjun Zhu

A matching set $M$ in a graph $G$ is a collection of edges of $G$ such that no two edges from $M$ share a vertex. In this paper we consider some parameters related to the matching of regular graphs. We find the sixth coefficient of the…

Combinatorics · Mathematics 2017-10-23 Neda Soltani , Saeid Alikhani

In this paper we give new upper bounds on the regularity of edge ideals whose resolutions are k-steps linear; surprisingly, the bounds are logarithmic in the number of variables. We also give various bounds for the projective dimension of…

Commutative Algebra · Mathematics 2011-10-13 Hailong Dao , Craig Huneke , Jay Schweig

We show that the co-chordal cover number of a graph G gives an upper bound for the Castelnuovo-Mumford regularity of the associated edge ideal. Several known combinatorial upper bounds of regularity for edge ideals are then easy…

Combinatorics · Mathematics 2014-09-10 Russ Woodroofe

Let K be a field and let S = K[x_1, ..., x_n] be a polynomial ring. Consider a homogenous ideal I in S. Let t_i denote reg(Tor_i (S/I, K)), the maximal degree of an ith syzygy of S/I. We prove bounds on the numbers t_i for i > n/2 purely in…

Commutative Algebra · Mathematics 2011-12-02 Jason McCullough

Let G be a simple graph without isolated vertices. For a vertex i in G, the degree d_i is the number of vertices adjacent to i and the average 2-degree m_i is the mean of the degrees of the vertices which are adjacent to i. The sequence of…

Combinatorics · Mathematics 2018-11-08 Yu-pei Huang , Chia-an Liu , Chih-wen Weng

Let $G$ be a finite simple graph and let $I_G$ denote its associated toric ideal in the polynomial ring $R$. For each integer $n\geq 2$, we completely determine all the possible values for the tuple $({\rm reg}(R/I_G), {\rm…

Commutative Algebra · Mathematics 2023-11-17 Kieran Bhaskara , Adam Van Tuyl

Considering regular graphs with every edge in a triangle we prove lower bounds for the number of triangles in such graphs. For r-regular graphs with r <= 5 we exhibit families of graphs with exactly that number of triangles and then…

Combinatorics · Mathematics 2024-08-02 James Preen

In this paper we investigate the question of normality for special monomial ideals in a polynomial ring over a field. We first include some expository sections that give the basics on the integral closure of a ideal, the Rees algebra on an…

Commutative Algebra · Mathematics 2007-05-23 Marie A. Vitulli

Let (P,<) be a finite poset and let G be its comparability graph. If cl(G) is the clutter of maximal cliques of G, we prove that cl(G) satisfies the max-flow min-cut property and that its edge ideal is normally torsion free. We prove that…

Commutative Algebra · Mathematics 2011-04-05 Luis A. Dupont , Rafael H Villarreal

Let $G$ be a finite simple graph and $I(G)$ denote the corresponding edge ideal. In this paper, we obtain upper bounds for the Castelnuovo-Mumford regularity of $I(G)^q$ in terms of certain combinatorial invariants associated with $G$. We…

Commutative Algebra · Mathematics 2021-02-02 A. V. Jayanthan , S. Selvaraja

In this paper, we give formulas for $v$-number of edge ideals of some graphs like path, cycle, 1-clique sum of a path and a cycle, 1-clique sum of two cycles and join of two graphs. For an $\mathfrak{m}$-primary monomial ideal $I\subset…

Commutative Algebra · Mathematics 2023-08-21 Prativa Biswas , Mousumi Mandal

We study the depth of classes of binomial edge ideals and classify all closed graphs whose binomial edge ideal is Cohen--Macaulay.

Commutative Algebra · Mathematics 2011-07-08 Viviana Ene , Juergen Herzog , Takayuki Hibi

We study the equality of the extremal Betti numbers of the binomial edge ideal $J_G$ and those of its initial ideal ${\rm in}(J_G)$ of a closed graph $G$. We prove that in some cases there is an unique extremal Betti number for ${\rm…

Commutative Algebra · Mathematics 2017-08-03 Hernán de Alba , Do Trong Hoang

We use the correspondence between hypergraphs and their associated edge ideals to study the minimal graded free resolution of squarefree monomial ideals. The theme of this paper is to understand how the combinatorial structure of a…

Commutative Algebra · Mathematics 2007-06-13 Huy Tai Ha , Adam Van Tuyl

In this paper, the problem of matching pairs of correlated random graphs with multi-valued edge attributes is considered. Graph matching problems of this nature arise in several settings of practical interest including social network…

Information Theory · Computer Science 2018-02-06 F. Shirani , S. Garg , E. Erkip

In this article, we give a new upper bound for the regularity of edge ideals of gap-free graphs, in terms of the their minimal triangulation. Let $H_U=G\cup F_U$ be a minimal triangulation of a gap-free graph $G$, for some maximal…

Combinatorics · Mathematics 2021-09-13 Rimpa Nandi , Ramakrishna Nanduri