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In this article we introduce and study the intersection graph of graded ideals of graded rings. The intersection graph of $G-$graded ideals of a graded ring $(R,G)$ is a simple graph, denoted by $Gr_G(R)$, whose vertices are the nontrivial…

Rings and Algebras · Mathematics 2020-08-11 T. Alraqad , H. Saber , R. Abu-Dawwas

A graph $G$ is called interval colorable if it has a proper edge coloring with colors $1,2,3,\dots$ such that the colors of the edges incident to every vertex of $G$ form an interval of integers. Not all graphs are interval colorable; in…

Combinatorics · Mathematics 2021-06-08 Armen S. Asratian , Carl Johan Casselgren , Petros A. Petrosyan

A good edge-labelling of a simple graph is a labelling of its edges with real numbers such that, for any ordered pair of vertices (u,v), there is at most one nondecreasing path from u to v. Say a graph is good if it admits a good…

Combinatorics · Mathematics 2012-11-13 Abbas Mehrabian

A connected dominating set in a graph is a dominating set of vertices that induces a connected subgraph. Following analogous studies in the literature related to independent sets, dominating sets, and total dominating sets, we study in this…

Combinatorics · Mathematics 2018-06-12 Nina Chiarelli , Martin Milanič

We study a class of finite groups $G$ which behave similarly to elementary abelian $p$-groups with $p$ prime, that is, there exists a subgroup $N$ such that all elements of $G\setminus N$ are conjugate or inverse-conjugate under $\Aut(G)$.…

Group Theory · Mathematics 2018-01-30 Lei Wang , Yin Liu

A graph $G=(V,E)$ is called $(k,k')$-choosable if for any total list assignment $L$ which assigns to each vertex $v$ a set $L(v)$ of $k$ real numbers, and assigns to each edge $e$ a set $L(e)$ of $k'$ real numbers, there is a mapping…

Combinatorics · Mathematics 2024-03-05 T. Wu , J. Luo , Y. Gao

A digraph $G$ is weightable if its edges can be weighted with real numbers such that the total weight in each directed cycle equals 1. There are several equivalent conditions: that $G$ admits a 0/1-weighting with the same property, or that…

Combinatorics · Mathematics 2026-01-21 Eli Berger , Daniel Carter , Paul Seymour

In an earlier paper the authors proved that limits of convergent graph sequences can be described by various structures, including certain 2-variable real functions called graphons, random graph models satisfying certain consistency…

Combinatorics · Mathematics 2009-02-10 László Lovász , Balázs Szegedy

Fix an integer $n \geq 1$, and consider the set of all connected finite simple graphs on $n$ vertices. For each $G$ in this set, let $I(G)$ denote the edge ideal of $G$ in the polynomial ring $R = K[x_1,\ldots,x_n]$. We initiate a study of…

Combinatorics · Mathematics 2020-03-18 Takayuki Hibi , Kyouko Kimura , Kazunori Matsuda , Adam Van Tuyl

Let $Z(\cal L)$ be the center of a Lie algebra $\cal L$ with Lie bracket $[\cdot, \cdot]$. %We then define The commuting graph of $\cal L$ is then defined by the simple undirected graph $\Gamma({\cal L})=(V_{\cal L},E_{\cal L})$ in which…

Rings and Algebras · Mathematics 2025-12-08 Hieu V. Ha , Vu A. Le , Tuan A. Nguyen , Tuyen T. M. Nguyen , Hoa D. Quang

A convex geometric graph $G$ is said to be packable if there exist edge-disjoint copies of $G$ in the complete convex geometric graph $K_n$ covering all but $o(n^2)$ edges. We prove that every convex geometric graph with cyclic chromatic…

Combinatorics · Mathematics 2024-02-27 Jiaxi Nie , Erlang Surya , Ji Zeng

Let $R$ be a ring with unity. The upper ideal relation graph $\Gamma_U(R)$ of the ring $R$ is a simple undirected graph whose vertex set is the set of all non-unit elements of $R$ and two distinct vertices $x, y$ are adjacent if and only if…

Rings and Algebras · Mathematics 2024-03-08 Barkha Baloda , Jitender Kumar

A graph is an instrument which is extensively utilized to model various problems in different fields. Up to date, many graphs have been developed to represent algebraic structures, particularly rings in order to study their properties. In…

Combinatorics · Mathematics 2021-02-25 Mohammad Hassan Mudaber , Nor Haniza Sarmin , Ibrahim Gambo

We introduce and study a generalization of conformal rigidity for graphs. A graph is $k$-conformally rigid if the uniform edge weights simultaneously maximize the sum of the $k$ smallest nontrivial Laplacian eigenvalues and minimize the sum…

Combinatorics · Mathematics 2026-05-12 Henrique Assumpção , Gabriel Coutinho , Chris Godsil

The main focus of this thesis is a generalization of covering arrays, covering arrays on graphs. Two vectors v,w in Z_k^n are qualitatively independent if for all ordered pairs (a,b) in Z_k x Z_k there is a position i in the vectors where…

Combinatorics · Mathematics 2007-05-23 Karen Meagher

For a given spatial graph $\mathcal{G} \subset \mathbb{R}^3$, we would like to find a closed orientable surface $\mathcal{S}$ embedded in $\mathbb{R}^3$ in which $\mathcal{G}$ is cellular embedded. However, for general $\mathcal{G}$ this is…

Geometric Topology · Mathematics 2025-10-21 Senja Barthel , Fabio Buccoliero

In this article, we introduce balance equations over commutative rings $R$ and associate $R$-weighted graphs to them so that solving balance equations corresponds to a consistent labeling of vertices of the associated graph. Our primary…

Combinatorics · Mathematics 2025-05-12 Harish Kishnani , Amit Kulshrestha

Let $R$ be a commutative ring. In \cite{KK_2025(1)}, the authors introduced $R$-weighted graphs as a tool for studying commutators in groups and Lie algebras. These graphs are equivalent to a system of balance equations, and their…

Combinatorics · Mathematics 2025-05-14 Harish Kishnani , Amit Kulshrestha

We investigate prime character degree graphs of solvable groups. In particular, we consider a family of graphs $\Gamma_{k,t}$ constructed by adjoining edges between two complete graphs in a one-to-one fashion. In this paper we determine…

Group Theory · Mathematics 2018-03-15 Mark W. Bissler , Jacob Laubacher

We discuss relations between the amenability of a graph and spectral properties of a random walk driven by a dynamical system. In order to include graphs which are not locally compact, we introduce the concept of amenability of weighted…

Dynamical Systems · Mathematics 2024-04-15 Johannes Jaerisch , Elaine Rocha , Manuel Stadlbauer
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