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For an increasing weighted tree $G_\omega$, we obtain an asymptotic value and a sharp bound on the index stability of the depth function of its edge ideal $I(G_\omega)$. Moreover, if $G_\omega$ is a strictly increasing weighted tree, we…

Commutative Algebra · Mathematics 2025-09-11 Truong Thi Hien , Jiaxin Li , Tran Nam Trung , Guangjun Zhu

Subgraph reconfiguration is a family of problems focusing on the reachability of the solution space in which feasible solutions are subgraphs, represented either as sets of vertices or sets of edges, satisfying a prescribed graph structure…

Data Structures and Algorithms · Computer Science 2018-03-19 Tesshu Hanaka , Takehiro Ito , Haruka Mizuta , Benjamin Moore , Naomi Nishimura , Vijay Subramanya , Akira Suzuki , Krishna Vaidyanathan

In this paper we study minimal free resolutions of some classes of monomial ideals. we first give a sufficient condition to check the minimality of the resolution obtained by the mapping cone. Using it, we obtain the Betti numbers of…

Commutative Algebra · Mathematics 2017-08-29 Leila Sharifan

Given a vertex-weighted oriented graph, we can associate to it a set of monomials. We consider the toric ideal whose defining map is given by these monomials. We find a generating set for the toric ideal for certain classes of graphs which…

Commutative Algebra · Mathematics 2021-07-12 Jennifer Biermann , Selvi Kara , Kuei-Nuan Lin , Augustine O'Keefe

We study the problem of maximizing the number of full degree vertices in a spanning tree $T$ of a graph $G$; that is, the number of vertices whose degree in $T$ equals its degree in $G$. In cubic graphs, this problem is equivalent to…

Combinatorics · Mathematics 2022-11-11 Sarah Acquaviva , Deepak Bal

Let $G=(V,E)$ be a finite simple graph. In this paper, we study the degree of the $h$-polynomial of the edge ideal of $G$ in relation to the independence number of $G$. Our approach is based on the value of the independence polynomial of…

Commutative Algebra · Mathematics 2026-03-17 Ton That Quoc Tan

Let G be a simple undirected graph on n vertices, and let I(G) \subseteq R = k[x_1,...,x_n] denote its associated edge ideal. We show that all chordal graphs G are sequentially Cohen-Macaulay; our proof depends upon showing that the…

Commutative Algebra · Mathematics 2007-06-13 Christopher A. Francisco , Adam Van Tuyl

For intractable problems on graphs of bounded treewidth, two graph parameters treedepth and vertex cover number have been used to obtain fine-grained complexity results. Although the studies in this direction are successful, we still need a…

Data Structures and Algorithms · Computer Science 2023-04-03 Tatsuya Gima , Tesshu Hanaka , Masashi Kiyomi , Yasuaki Kobayashi , Yota Otachi

Given any monomial ideal $ I $ minimally generated by $ q $ monomials, we define a simplicial complex $\mathbb{M}_q^2$ that supports a resolution of $ I^2 $. We also define a subcomplex $\mathbb{M}^2(I)$, which depends on the monomial…

Commutative Algebra · Mathematics 2025-05-19 Susan M. Cooper , Sara Faridi , Hasan Mahmood

The independence complex $\mathrm{Ind}(G)$ of a graph $G$ is the simplicial complex formed by its independent sets. This article introduces a deformation of the simplicial boundary map of $\mathrm{Ind}(G)$ that gives rise to a double…

Algebraic Topology · Mathematics 2020-10-01 Marko Berghoff

Consider an ideal $I\subset K[x_1,..., x_n]$, with $K$ an arbitrary field, generated by monomials of degree two. Assuming that $I$ does not have a linear resolution, we determine the step $s$ of the minimal graded free resolution of $I$…

Commutative Algebra · Mathematics 2008-11-13 Oscar Fernandez-Ramos , Philippe Gimenez

For graphs $G$ and $H$, a \emph{homomorphism} from $G$ to $H$ is an edge-preserving mapping from the vertex set of $G$ to the vertex set of $H$. For a fixed graph $H$, by \textsc{Hom($H$)} we denote the computational problem which asks…

Computational Complexity · Computer Science 2020-02-20 Karolina Okrasa , Paweł Rzążewski

A graph $G$ is Ramsey for a graph $H$ if every 2-colouring of the edges of $G$ contains a monochromatic copy of $H$. We consider the following question: if $H$ has bounded treewidth, is there a `sparse' graph $G$ that is Ramsey for $H$? Two…

Combinatorics · Mathematics 2019-07-30 Nina Kamcev , Anita Liebenau , David R. Wood , Liana Yepremyan

Given a 3-uniform hypergraph H, its 2-intersection graph G has for vertex set the hyperedges of H and ee' is an edge of G whenever e and e' have exactly two common vertices in H. Di Marco et al. prove that deciding wether a graph G is the…

Combinatorics · Mathematics 2023-05-24 Niccolò Di Marco , Andrea Frosini , Christophe Picouleau

An $({\cal I},{\cal F}_d)$-partition of a graph is a partition of the vertices of the graph into two sets $I$ and $F$, such that $I$ is an independent set and $F$ induces a forest of maximum degree at most $d$. We show that for all $M<3$…

Discrete Mathematics · Computer Science 2016-06-15 François Dross , Mickael Montassier , Alexandre Pinlou

Graph spectra are an important class of structural features on graphs that have shown promising results in enhancing Graph Neural Networks (GNNs). Despite their widespread practical use, the theoretical understanding of the power of…

Machine Learning · Computer Science 2025-03-04 Jingchu Gai , Yiheng Du , Bohang Zhang , Haggai Maron , Liwei Wang

We consider the problem of how much edge connectivity is necessary to force a graph G to contain a fixed graph H as an immersion. We show that if the maximum degree in H is D, then all the examples of D-edge connected graphs which do not…

Combinatorics · Mathematics 2014-01-14 Daniel Marx , Paul Wollan

In this paper, we study the notion of chordality and cycles in hypergraphs from a commutative algebraic point of view. The corresponding concept of chordality in commutative algebra is having a linear resolution. However, there is no…

Combinatorics · Mathematics 2020-03-27 Ashkan Nikseresht , Rashid Zaare-Nahandi

For a finite group $G$, we define the inclusion graph of subgroups of $G$, denoted by $\mathcal I(G)$, is a graph having all the proper subgroups of $G$ as its vertices and two distinct vertices $H$ and $K$ in $\mathcal I(G)$ are adjacent…

Group Theory · Mathematics 2016-04-29 P. Devi , R. Rajkumar

The following measure of sparsity of multigraphs refining the maximum average degree: For $a>0$ and an arbitrary real $b$, a multigraph $H$ is \emph{$(a,b)$-sparse} if it is loopless and for every $A\subseteq V(H)$ with $|A|\geq 2$, the…

Combinatorics · Mathematics 2025-05-26 Ilkyoo Choi , Alexandr V. Kostochka , Matthew Yancey