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For an arbitrary ideal $I$ in a polynomial ring $R$ we define the notion of initially regular sequences on $R/I$. These sequences share properties with regular sequences. In particular, the length of an initially regular sequence provides a…

Commutative Algebra · Mathematics 2019-07-02 Louiza Fouli , Huy Tai Ha , Susan Morey

We use initially regular sequences that consist of linear sums to explore the depth of $R/I^2$, when $I$ is a monomial ideal in a polynomial ring $R$. We give conditions under which these linear sums form regular or initially regular…

Commutative Algebra · Mathematics 2022-08-30 Louiza Fouli , Tài Huy Hà , Susan Morey

Let $G$ be a finite simple graph with edge ideal $I(G)$. Let $J(G)$ denote the Alexander dual of $I(G)$. We show that a description of all induced cycles of odd length in $G$ is encoded in the associated primes of $J(G)^2$. This result…

Commutative Algebra · Mathematics 2010-01-08 Christopher A. Francisco , Huy Tai Ha , Adam Van Tuyl

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 prove that the edge ideals of line and cyclic graphs and their quotient rings satisfy the Stanley conjecture. We compute the Stanley depth for the quotient ring of the edge ideal associated to a cycle graph of length $n$, given a precise…

Commutative Algebra · Mathematics 2016-03-29 Mircea Cimpoeas

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 unicyclic graph then for all $s \geq 1$ the regularity of $I(G)^s$ is exactly $2s+\text{reg}(I(G))-2$. We also…

Commutative Algebra · Mathematics 2022-09-30 Ali Alilooee , Selvi Kara , S. Selvaraja

We give a necessary and sufficient graph-theoretic characterization of toric ideals of graphs that are unimodular. As a direct consequence, we provide the structure of unimodular graphs by proving that the incidence matrix of a graph $G$ is…

Commutative Algebra · Mathematics 2025-10-15 Christos Tatakis

We find a class of block graphs whose binomial edge ideals have minimal regularity. As a consequence, we characterize the trees whose binomial edge ideals have minimal regularity. Also, we show that the binomial edge ideal of a block graph…

Commutative Algebra · Mathematics 2014-02-11 Faryal Chaudhry , Ahmet Dokuyucu , Rida Irfan

We study monomial cut ideals associated to a graph $G$, which are a monomial analogue of toric cut ideals as introduced by Sturmfels and Sullivant. Primary decompositions, projective dimensions, and Castelnuovo-Mumford regularities are…

Commutative Algebra · Mathematics 2021-12-09 Jürgen Herzog , Masoomeh Rahimbeigi , Tim Römer

We study graphs on $n$ vertices which have $2n-2$ edges and no proper induced subgraphs of minimum degree $3$. Erd\H{o}s, Faudree, Gy\'arf\'as, and Schelp conjectured that such graphs always have cycles of lengths $3,4,5,\dots, C(n)$ for…

Combinatorics · Mathematics 2014-08-25 Lothar Narins , Alexey Pokrovskiy , Tibor Szabó

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

We consider ideals in a polynomial ring that are generated by regular sequences of homogeneous polynomials and are stable under the action of the symmetric group permuting the variables. In previous work, we determined the possible…

Commutative Algebra · Mathematics 2019-08-15 Federico Galetto , Anthony V. Geramita , David L. Wehlau

This research focuses on analyzing the depth of generalized binomial edge ideals. We extend the notion of $d$-compatible map for the pairs of a complete graph and an arbitrary graph, and using it, we give a combinatorial lower bound for the…

Commutative Algebra · Mathematics 2024-01-15 Anuvinda J , Ranjana Mehta , Kamalesh Saha

We compute the projective dimension and regularity of $3$-path ideals of arbitrary graphs with at most one cycle.

Commutative Algebra · Mathematics 2024-02-27 Nguyen Thu Hang , Thanh Vu

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

We classify all unicycle graphs whose edge-binomials form a $d$-sequence, particularly linear type binomial edge ideals. We also classify unicycle graphs whose parity edge-binomials form a $d$-sequence. We study the regularity of powers of…

Commutative Algebra · Mathematics 2024-03-19 Marie Amalore Nambi , Neeraj Kumar

Let $I$ be the edge ideal of a cycle of length $n \ge 5$ over a polynomial ring $S = \mathrm{k}[x_1,\ldots,x_n]$. We prove that for $2 \le t < \lceil (n+1)/2 \rceil$, $$\operatorname{depth} (S/I^t) = \lceil \frac{n -t + 1}{3} \rceil.$$ When…

Commutative Algebra · Mathematics 2023-08-03 Nguyen Cong Minh , Tran Nam Trung , Thanh Vu

Let $G$ be a connected simple graph on the vertex set $[n]$. Banerjee-Betancourt proved that $depth(S/J_G)\leq n+1$. In this article, we prove that if $G$ is a unicyclic graph, then the depth of $S/J_G$ is bounded below by $n$. Also, we…

Commutative Algebra · Mathematics 2021-12-10 Rajib Sarkar

We study the relationship between depth and regularity of a homogeneous ideal I and those of (I,f) and I:f, where f is a linear form or a monomial. Our results has several interesting consequences on depth and regularity of edge ideals of…

Commutative Algebra · Mathematics 2018-01-30 Giulio Caviglia , Huy Tai Ha , Jürgen Herzog , Manoj Kummini , Naoki Terai , Ngo Viet Trung

We introduce the concept of minimum edge cover for an induced subgraph in a graph. Let $G$ be a unicyclic graph with a unique odd cycle and $I=I(G)$ be its edge ideal. We compute the exact values of all symbolic defects of $I$ using the…

Commutative Algebra · Mathematics 2022-04-13 Mousumi Mandal , Dipak Kumar Pradhan
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