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Let $\operatorname{pd}(I(G))$ and $\operatorname{reg}(I(G))$ respectively denote the projective dimension and the regularity of the edge ideal $I(G)$ of a graph $G$. For any positive integer $n$, we determine all pairs…

Commutative Algebra · Mathematics 2022-12-13 Nursel Erey , Takayuki Hibi

In this paper, we investigate the degree of $h$-polynomials of edge ideals of finite simple graphs. In particular, we provide combinatorial formulas for the degree of the $h$-polynomial for various fundamental classes of graphs such as…

Commutative Algebra · Mathematics 2024-08-26 Jennifer Biermann , Selvi Kara , Augustine O'Keefe , Joseph Skelton , Gabriel Sosa

We study the regularity of binomial edge ideals. For a closed graph $G$ we show that the regularity of the binomial edge ideal $J_G$ coincides with the regularity of $\ini_{\lex}(J_G)$ and can be expressed in terms of the combinatorial data…

Commutative Algebra · Mathematics 2013-07-09 Viviana Ene , Andrei Zarojanu

In this paper we provide some exact formulas for the projective dimension and the regularity of edge ideals of vertex-weighted oriented unicyclic graphs. These formulas are in function of the weight of the vertices, the numbers of edges. We…

Commutative Algebra · Mathematics 2023-09-20 Guangjun Zhu , Hong Wang

In this paper, we obtain a combinatorial formula for computing the Betti numbers in the linear strand of edge ideals of bipartite Kneser graphs. We deduce lower and upper bounds for regularity of powers of edge ideals of these graphs in…

Commutative Algebra · Mathematics 2021-05-14 Ajay Kumar , Pavinder Singh , Rohit Verma

We obtain the exact values for depth and projective dimension and lower bounds for Stanley depth of the quotient rings of the edge ideals associated with all cubic circulant graphs.

Commutative Algebra · Mathematics 2023-07-25 Bakhtawar Shaukat , Muhammad Ishaq , Ahtsham ul Haq , Zahid Iqbal

Let $G$ be a finite simple graph. We give a lower bound for the Castelnuovo-Mumford regularity of the toric ideal $I_G$ associated to $G$ in terms of the sizes and number of induced complete bipartite graphs in $G$. When $G$ is a chordal…

Commutative Algebra · Mathematics 2016-05-24 Jennifer Biermann , Augustine O'Keefe , Adam Van Tuyl

Let $D$ be a weighted oriented graph with the underlying graph $G$ and $I(D), I(G) $ be the edge ideals corresponding to $D$ and $G$ respectively. We show that the regularity of edge ideal of a certain class of weighted oriented graph…

Combinatorics · Mathematics 2022-04-12 Mousumi Mandal , Dipak Kumar Pradhan

We first characterise graphs with binomial edge ideals of K\"onig type as those for which the path covering number is equal to a minor variant of the scattering number. These are well-studied graph-theoretic invariants, allowing us to apply…

Commutative Algebra · Mathematics 2026-05-26 David Williams

Edge ideals of finite simple graphs $G$ on $n$ vertices are the ideals $I(G)$ of the polynomial ring $S$ in $n$ variables generated by the quadratic monomials associated with the edges of $G$. In this paper, we consider the possible pairs…

Commutative Algebra · Mathematics 2023-01-18 Akihiro Higashitani , Akane Kanno , Ryota Ueji

Let B_{2t} be a bipartite planar graph with an even number of regions. We are able to find bounds for the graded Betti numbers and the projective dimension of the quotient ring associated to the graph. We also will investigate the minimal…

Commutative Algebra · Mathematics 2024-04-01 Maurizio Imbesi , Monica La Barbiera

We study unmixed and Cohen-Macaulay properties of the binomial edge ideal of some classes of graphs. We compute the depth of the binomial edge ideal of a generalized block graph. We also characterize all generalized block graphs whose…

Commutative Algebra · Mathematics 2015-06-04 Dariush Kiani , Sara Saeedi Madani

We prove that level binomial edge ideals with regularity 2 and pseudo-Gorenstein binomial edge ideals with regularity 3 are cones, and we describe them completely. Also, we characterize level and pseudo-Gorenstein binomial edge ideals of…

Commutative Algebra · Mathematics 2023-08-11 Giancarlo Rinaldo , Rajib Sarkar

In this paper, we first give some sufficient criteria for normality of monomial ideals. As applications, we show that closed neighborhood ideals of complete bipartite graphs are normal, and hence satisfy the (strong) persistence property.…

Commutative Algebra · Mathematics 2023-08-15 Mehrdad Nasernejad , Somayeh Bandari , Leslie G. Roberts

Let X* be a subset of an affine space A^s, over a finite field K, which is parameterized by the edges of a clutter. Let X and Y be the images of X* under the maps x --> [x] and x --> [(x,1)] respectively, where [x] and [(x,1)] are points in…

Commutative Algebra · Mathematics 2013-06-24 Maria Vaz Pinto , Rafael H. Villarreal

Let I(G) be the edge ideal associated to a simple graph G. We study the graded Betti numbers that appear in the linear strand of the minimal free resolution of I(G).

Commutative Algebra · Mathematics 2007-05-23 Mike Roth , Adam Van Tuyl

For the set of graphs with a given degree sequence, consisting of any number of $2's$ and $1's$, and its subset of bipartite graphs, we characterize the optimal graphs who maximize and minimize the number of $m$-matchings. We find the…

Combinatorics · Mathematics 2008-01-16 S. Friedland , E. Krop , K. Markström

In this paper we use polarization to study the behavior of the depth and regularity of a monomial ideal $I$, locally at a variable $x_i$, when we lower the degree of all the highest powers of the variable $x_i$ occurring in the minimal…

Commutative Algebra · Mathematics 2019-04-04 Jose Martínez-Bernal , Susan Morey , Rafael H. Villarreal , Carlos E. Vivares

The regularity of an edge ideal of a finite simple graph $G$ is at least the induced matching number of $G$ and is at most the minimum matching number of $G$. If $G$ possesses a dominating inuduced matching, i.e., an induced matching which…

Combinatorics · Mathematics 2015-08-27 Takayuki Hibi , Akihiro Higashitani , Kyouko Kimura , Akiyoshi Tsuchiya

In this paper we prove that if $I(G)$ is a bipartite edge ideal with regularity three then for all $s\geq 2$ the regularity of $I(G)^s$ is exactly $2s+1$.

Commutative Algebra · Mathematics 2014-08-13 Ali Alilooee , Arindam Banerjee