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We graph-theoretically characterize triangle-free Gorenstein graphs $G$. As an application, we classify when $I(G)^2$ is Cohen-Macaulay.

Commutative Algebra · Mathematics 2015-09-01 Do Trong Hoang , Tran Nam Trung

Let $D$ be a weighted oriented graph and $I(D)$ be its edge ideal. If $D$ contains an induced odd cycle of length $2n+1$, under certain condition we show that $ {I(D)}^{(n+1)} \neq {I(D)}^{n+1}$. We give necessary and sufficient condition…

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

We introduce binomial edge ideals attached to a simple graph $G$ and study their algebraic properties. We characterize those graphs for which the quadratic generators form a Gr\"obner basis in a lexicographic order induced by a vertex…

Commutative Algebra · Mathematics 2009-10-16 Juergen Herzog , Takayuki Hibi , Freyja Hreinsdottir , Thomas Kahle , Johannes Rauh

Associated to a simple undirected graph G is a simplicial complex whose faces correspond to the independent sets of G. We call a graph G shellable if this simplicial complex is a shellable simplicial complex in the non-pure sense of…

Combinatorics · Mathematics 2007-11-06 Adam Van Tuyl , Rafael H. Villarreal

A combinatorial property that characterizes Cohen-Macaulay binomial edge ideals has long been elusive. A recent conjecture ties the Cohen-Macaulayness of a binomial edge ideal $J_G$ to special disconnecting sets of vertices of its…

Commutative Algebra · Mathematics 2022-12-20 Davide Bolognini , Antonio Macchia , Giancarlo Rinaldo , Francesco Strazzanti

In this paper we study irreducible representations and symbolic Rees algebras of monomial ideals. Then we examine edge ideals associated to vertex-weighted oriented graphs. These are digraphs having no oriented cycles of length two with…

Commutative Algebra · Mathematics 2018-10-23 Philippe Gimenez , Jose Martínez-Bernal , Aron Simis , Rafael H. Villarreal , Carlos E. Vivares

Let C be a clutter and let I(C) be its edge ideal. This is a survey paper on the algebraic and combinatorial properties of R/I(C) and C, respectively. We give a criterion to estimate the regularity of R/I(C) and apply this criterion to give…

Commutative Algebra · Mathematics 2012-05-23 Susan Morey , Rafael H. Villarreal

We introduce and study the weighted $r$-path ideal of a weighted graph $G_\omega$, which is a common generalization of Conca and De Negri's $r$-path ideal for unweighted graphs and Paulsen and Sather-Wagstaff's edge ideal of the weighted…

Commutative Algebra · Mathematics 2014-08-08 Bethany Kubik , Sean Sather-Wagstaff

In this article, we study algebraic properties of binomial edge ideals of Levi graphs associated with certain plane curve arrangements. Using combinatorial properties of Levi graphs, we discuss the Cohen-Macaulayness of binomial edge ideals…

Commutative Algebra · Mathematics 2024-03-29 Rupam Karmakar , Rajib Sarkar , Aditya Subramaniam

We introduce a class of ideals generated by a set of 2-minors of $m\times n$-matrix of indeterminates indexed by a pair of graphs. This class of ideals is a natural common generalization of binomial edge ideals and ideals generated by…

Commutative Algebra · Mathematics 2015-01-14 Viviana Ene , Jürgen Herzog , Takayuki Hibi , Ayesha Asloob Qureshi

Let $S=K[x_1,\dots,x_n]$ be the polynomial ring over a field $K$ and $I\subset S$ be a squarefree monomial ideal generated in degree $n-2$. Motivated by the remarkable behavior of the powers of $I$ when $I$ admits a linear resolution, as…

Commutative Algebra · Mathematics 2025-08-28 Antonino Ficarra , Somayeh Moradi

We determine all possible triples of depth, dimension, and regularity of edge ideals of weighted oriented graphs with a fixed number of vertices. Also, we compute all the possible Betti table sizes of edge ideals of weighted oriented trees…

Commutative Algebra · Mathematics 2025-04-18 Trung Chau , Richie Sheng , Deborah Wooton

We prove that, for the edge ideal of a cactus graph, the arithmetical rank is bounded above by the sum of the number of cycles and the maximum height of its associated primes. The bound is sharp, but in many cases it can be improved.…

Commutative Algebra · Mathematics 2017-03-28 Margherita Barile , Antonio Macchia

We prove that wheels and block graphs have sequentially Cohen-Macaulay binomial edge ideals. Moreover, we provide a construction of new families of sequentially Cohen-Macaulay graphs by cones.

Commutative Algebra · Mathematics 2025-07-08 Ernesto Lax , Giancarlo Rinaldo , Francesco Romeo

Let $D$ be a weighted oriented graph and $I(D)$ be its edge ideal. We provide one method to find all the minimal generators of $ I_{\subseteq C} $, where $ C $ is a maximal strong vertex cover of $D$ and $ I_{\subseteq C} $ is the…

Commutative Algebra · Mathematics 2023-06-16 Mousumi Mandal , Dipak Kumar Pradhan

Let $G$ be a simple graph on $n$ vertices and let $J_{G,m}$ be the generalized binomial edge ideal associated to $G$ in the polynomial ring $K[x_{ij}, 1\le i \le m, 1\le j \le n]$. We classify the Cohen-Macaulay generalized binomial edge…

Commutative Algebra · Mathematics 2023-07-04 Luca Amata , Marilena Crupi , Giancarlo Rinaldo

Let G be a simple undirected graph. We find the number of maximal independent sets in complete t-partite graphs. We will show that vertex decomposability and shellability are equivalent in this graphs. Also, we obtain an equivalent…

Commutative Algebra · Mathematics 2012-05-29 Seyyede Masoome Seyyedi , Farhad Rahmati , Mahdis Saeedi

Let G be a bipartite graph with edge ideal I(G) whose quotient ring R/I(G) is sequentially Cohen-Macaulay. We prove: (1) the independence complex of G must be vertex decomposable, and (2) the Castelnuovo-Mumford regularity of R/I(G) can be…

Commutative Algebra · Mathematics 2009-06-02 Adam Van Tuyl

We define a simple graph as compact if it lacks even cycles and satisfies the odd-cycle condition. Our focus is on classifying all compact graphs and examining the characteristics of their edge rings. Let $G$ be a compact graph and…

Commutative Algebra · Mathematics 2024-05-08 Zexin Wang , Dancheng Lu

For a graph $G$, Bolognini et al. have shown $J_{G}$ is strongly unmixed $\Rightarrow$ $J_{G}$ is Cohen-Macaulay $\Rightarrow$ $G$ is accessible, where $J_{G}$ denotes the binomial edge ideals of $G$. Accessible and strongly unmixed…

Commutative Algebra · Mathematics 2022-03-10 Kamalesh Saha , Indranath Sengupta