English
Related papers

Related papers: Algebraic invariants of weighted oriented graphs

200 papers

We introduce a new class of polynomial ideals associated to a simple graph, $G$. Let $K[E_G]$ be the polynomial ring on the edges of $G$ and $K[V_G]$ the polynomial ring on the vertices of $G$. We associate to $G$ an ideal, $I(X_G)$,…

Commutative Algebra · Mathematics 2019-09-09 Jorge Neves , Maria Vaz Pinto , Rafael H. Villarreal

We classify generalized block graphs whose binomial edge ideals admit a unique extremal Betti number. We prove that the Castelnuovo-Mumford regularity of binomial edge ideals of generalized block graphs is bounded below by $m(G)+1$, where…

Commutative Algebra · Mathematics 2021-12-07 Arvind Kumar

Let $\mathcal{D}$ be a weighted oriented graph and let $I(\mathcal{D})$ be its edge ideal. Under a natural condition that the underlying (undirected) graph of $\mathcal{D}$ contains a perfect matching consisting of leaves, we provide…

Commutative Algebra · Mathematics 2018-05-14 Huy Tài Hà , Kuei-Nuan Lin , Susan Morey , Enrique Reyes , Rafael H. Villarreal

We study the homological algebra of edge ideals of Erd\"{o}s-R\'enyi random graphs. These random graphs are generated by deleting edges of a complete graph on $n$ vertices independently of each other with probability $1-p$. We focus on some…

Combinatorics · Mathematics 2021-05-05 Arindam Banerjee , D. Yogeshwaran

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 give a bound on the Castelnuovo-Mumford regularity of a homogeneous ideals I, in a polynomial ring A, in terms of number of variables and the degrees of generators, when the dimension of A/I is at most two. This bound improves the one…

Commutative Algebra · Mathematics 2007-05-23 Marc Chardin , Amadou Lamine Fall

We prove that the projective dimension of any (hyper)graph can be bounded from above by the (Castelnuovo-Mumford) regularity of its Levi graph (or incidence bipartite graph). This in particular brings the use of regularity's upper bounds on…

Combinatorics · Mathematics 2016-05-11 Türker Bıyıkoğlu , Yusuf Civan

We give a lower bound for the Castelnuovo-Mumford regularity of binomial edge ideals of block graphs by computing the two distinguished extremal Betti numbers of a new family of block graphs, called flower graphs. Moreover, we present a…

Commutative Algebra · Mathematics 2019-08-05 Carla Mascia , Giancarlo Rinaldo

We study the asymptotic behavior of the Castelnuovo-Mumford regularity along chains of graded ideals in increasingly larger polynomial rings that are invariant under the action of symmetric groups. A linear upper bound for the regularity of…

Commutative Algebra · Mathematics 2020-09-09 Dinh Van Le , Uwe Nagel , Hop D. Nguyen , Tim Roemer

In this paper, we explain the regularity, projective dimension and depth of edge ideal of some classes of graphs in terms of invariants of graphs. We show that for a $C_5$-free vertex decomposable graph $G$, $\T{reg}(R/I(G))= c_G$, where…

Commutative Algebra · Mathematics 2017-01-24 Fahimeh Khosh-Ahang , Somayeh Moradi

We prove two recent conjectures on some upper bounds for the Castelnuovo-Mumford regularity of the binomial edge ideals of some different classes of graphs. We prove the conjecture of Matsuda and Murai for graphs which has a cut edge or a…

Commutative Algebra · Mathematics 2013-11-19 Dariush Kiani , Sara Saeedi Madani

In this article, we survey the recent results on the Castelnuovo-Mumford regularity of binomial edge ideals and generalized binomial edge ideals. We also generalize some of the known upper bounds for binomial edge ideals to the case of…

Commutative Algebra · Mathematics 2025-08-19 A. V. Jayanthan , Arvind Kumar

Let $G$ be a finite simple graph and let $I(G)$ denote its edge ideal. For $q \ge 1$, the $q$-th squarefree power $I(G)^{[q]}$ is generated by squarefree monomials corresponding to matchings of size $q$ in $G$. We denote by…

Commutative Algebra · Mathematics 2026-04-21 Sanjoy Das , Arka Ghosh , S Selvaraja

In this paper, we study the componentwise linearity of edge ideals of weighted oriented graphs. We show that if $D$ is a weighted oriented graph whose edge ideal $I(D)$ is componentwise linear, then the underlying simple graph $G$ of $D$ is…

Commutative Algebra · Mathematics 2023-10-02 Manohar Kumar , Ramakrishna Nanduri , Kamalesh Saha

We describe a parallel polynomial time algorithm for computing the topological Betti numbers of a smooth complex projective variety $X$. It is the first single exponential time algorithm for computing the Betti numbers of a significant…

Algebraic Geometry · Mathematics 2011-12-13 Peter Scheiblechner

Since the introduction of binomial edge ideals $J_{G}$ by Herzog et al. and independently Ohtani, there has been significant interest in relating algebraic invariants of the binomial edge ideal with combinatorial invariants of the…

Commutative Algebra · Mathematics 2025-03-24 Adam LaClair

Let $A$ be a noetherian connected graded algebra. We introduce and study homological invariants that are weighted sums of the homological and internal degrees of cochain complexes of graded $A$-modules, providing weighted versions of…

Rings and Algebras · Mathematics 2023-06-12 Ellen Kirkman , Robert Won , James J. Zhang

Let $G$ be a finite simple graph with the vertex set $V$ and let $I_G$ be its edge ideal in the polynomial ring $S=\mathbb{K}[x_V]$. In this paper, we compute the depth and the Castelnuovo--Mumford regularity of $S/I_G$ when $G=G_1\circ…

Commutative Algebra · Mathematics 2023-09-29 Yulong Yang , Guangjun Zhu , Yijun Cui , Shiya Duan

In this paper we study the Castelnuovo-Mumford regularity of the path ideals of finite simple graphs. We find new upper bounds for various path ideals of gap free graphs. In particular we prove that the path ideals of gap free and claw…

Commutative Algebra · Mathematics 2014-09-15 Arindam Banerjee

We investigate the Castelnuovo-Mumford regularity and the multiplicity of the toric ring associated with a three-dimensional Ferrers diagram. In particular, in the rectangular case, we provide direct formulas for these two important…

Commutative Algebra · Mathematics 2022-07-19 Kuei-Nuan Lin , Yi-Huang Shen