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Let $G$ be a $(C_4, 2K_2)$-free graph with edge ideal $I(G)\subset \Bbbk[x_1,\dots , x_n]$. We show that $I(G)^s$ has linear resolution for every $s\geq 2$. Also, we show that every power of the vertex cover ideal of $G$ has linear…

Commutative Algebra · Mathematics 2020-03-03 Nursel Erey

We introduce the abstract notion of squarefree-power-like functions, which unify the sequences of squarefree ordinary and symbolic powers of squarefree monomial ideals. By employing the Tor-vanishing criteria for mixed sums of ideals, we…

Commutative Algebra · Mathematics 2025-10-17 Trung Chau , Kanoy Kumar Das , Amit Roy , Kamalesh Saha

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

The well-known 1-2-3 Conjecture asserts that the edges of every graph without isolated edges can be weighted with $1$, $2$ and $3$ so that adjacent vertices receive distinct weighted degrees. This is open in general, while it is known to be…

Combinatorics · Mathematics 2019-12-19 Jakub Przybyło

Let $G=W(C_{n})$ be a whiskered cycle graph with edge ideal $I=I(G)$. We prove that for every $s\geq 1$, the equality ${\rm reg}(I^{s})=2s+\lceil \frac{n-1}{2}\rceil-1$ holds.

Commutative Algebra · Mathematics 2015-05-25 Mahdieh Moghimian , Seyed Amin Seyed Fakhari , Siamak Yassemi

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 very well-covered graph then for all $s \geq 2$ the regularity of $I(G)^s$ is exactly $2s+\nu(G)-1$.

Commutative Algebra · Mathematics 2019-01-03 A V Jayanthan , S Selvaraja

Let $G$ be a simple graph on $n$ vertices. We introduce the notion of bipartite connectivity of $G$, denoted by $\operatorname{bc}(G)$ and prove that $$\lim_{s \to \infty} \operatorname{depth} (S/I(G)^{(s)}) \le \operatorname{bc}(G),$$…

Commutative Algebra · Mathematics 2024-06-19 Nguyen Cong Minh , Tran Nam Trung , Thanh Vu

Let $I(G)$ be the edge ideal of a bicyclic graph. In this paper, we characterize the Castelnuovo-Mumford regularity of $I(G)$ in terms of the induced matching number of $G$. For the base case of this family of graphs, i.e. dumbbell graph,…

Commutative Algebra · Mathematics 2018-10-18 Yairon Cid-Ruiz , Sepehr Jafari , Navid Nemati , Beatrice Picone

We classify all normal edge ideals of edge-weighted graphs.

Commutative Algebra · Mathematics 2024-07-24 Thanh Vu , Guangjun Zhu

We study convex entire graphs evolving with normal velocity equal to a positive power of the mean curvature. Under mild assumptions we prove longtime existence.

Differential Geometry · Mathematics 2011-12-20 Martin Franzen

Squarefree powers of edge ideals are intimately related to matchings of the underlying graph. In this paper we give bounds for the regularity of squarefree powers of edge ideals, and we consider the question of when such powers are linearly…

Commutative Algebra · Mathematics 2019-09-26 Nursel Erey , Jürgen Herzog , Takayuki Hibi , Sara Saeedi Madani

We obtain sharp bounds for the number of n-cycles in a finite graph as a function of the number of edges, and prove that the complete graph is optimal in more ways than could be imagined. En route, we prove some sharp estimates on power…

Combinatorics · Mathematics 2007-05-23 Igor Rivin

We characterise the form of all simple, finite graphs for which the girth of the graph is equal to the circumference of the graph. We apply this to prove a bound on the number of edges in such a graph.

Combinatorics · Mathematics 2022-10-11 Lewis Stanton , Jeffrey Thompson

A normal edge-coloring of a cubic graph is a proper edge-coloring, in which every edge is adjacent to edges colored with four distinct colors or to edges colored with two distinct colors. It is conjectured that $5$ colors suffice for a…

Combinatorics · Mathematics 2025-08-29 Igor Fabrici , Borut Lužar , Roman Soták , Diana Švecová

In this paper, we investigate when symbolic and ordinary powers of the parity binomial edge ideal of a graph fail to be equal. It turns out that if $\mathcal{I}_{G}$ is the parity binomial edge ideal of a graph $G$, then in each of the…

Commutative Algebra · Mathematics 2023-11-07 Nadia Taghipour , Shamila Bayati , Farhad Rahmati

We determine the arithmetical rank of every edge ideal of a Ferrers graph.

Commutative Algebra · Mathematics 2007-05-23 Margherita Barile

Let $G$ be a graph with edge ideal $I(G)$. We recall the notions of $\min-match_{\{K_2, C_5\}}(G)$ and $\ind-match_{\{K_2, C_5\}}(G)$ from \cite{sy}. We show that $${\rm reg}(I(G)^s)\leq 2s+\min-match_{\{K_2, C_5\}}(G)-1,$$for all $s\geq…

Commutative Algebra · Mathematics 2019-05-14 Seyed Amin Seyed Fakhari , Siamak Yassemi

This paper gives some exact formulas for the depth of powers of the edge ideal of an edge-weighted integrally closed cycle.

Commutative Algebra · Mathematics 2025-01-28 Guangjun Zhu , Jiaxin Li , Yijun Cui , Yi Yang

We state a conjecture on the stability of Betti diagrams of powers of monomial ideals.

Commutative Algebra · Mathematics 2013-12-30 Alexander Engstrom

Let $I(G)$ be the edge ideal of a simple graph $G$. In this paper, we will give sufficient and necessary combinatorial conditions of $G$ in which the second symbolic and ordinary power of its edge ideal are Cohen-Macaulay (resp. Buchsbaum,…

Commutative Algebra · Mathematics 2013-03-01 Do Trong Hoang , Nguyen Cong Minh , Tran Nam Trung
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