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An isolating set in a graph is a set $X$ of vertices such that every edge of the graph is incident with a vertex of $X$ or its neighborhood. The isolation number of a graph, or equivalently the vertex-edge domination number, is the minimum…

Combinatorics · Mathematics 2024-05-22 Geoffrey Boyer , Wayne Goddard

The interplay between groups and graphs have been the most famous and productive area of algebraic graph theory. In this paper, we introduce and study the graphs whose vertex set is group G such that two distinct vertices a and b having…

Combinatorics · Mathematics 2019-01-01 Shafiq Ur Rehman , Abdul Qudair Baig , Muhammad Imran , Zia Ullah Khan

We continue the study of prime graphs of finite groups, also known as Gruenberg-Kegel graphs. The vertices of the prime graph of a finite group are the prime divisors of the group order, and two vertices $p$ and $q$ are connected by an edge…

An $i$-independent set is a set of vertices whose pairwise distance is at least $i+1$. A proper coloring (resp. a square coloring) of a graph is a partition of its vertices into independent (resp. $2$-independent) sets. A packing…

Combinatorics · Mathematics 2025-09-04 Ilkyoo Choi , Xujun Liu

The dissociation number ${\rm diss}(G)$ of a graph $G$ is the maximum order of a set of vertices of $G$ inducing a subgraph that is of maximum degree at most $1$. Computing the dissociation number of a given graph is algorithmically hard…

Combinatorics · Mathematics 2022-02-21 Felix Bock , Johannes Pardey , Lucia D. Penso , Dieter Rautenbach

In this note we consider the independent domination polynomial problem along with their unimodal and log-concave properties which were earlier studied by G\"ursoy, \"Ulker and G\"ursoy (Soft Comp. 2022). We show that the independent…

Combinatorics · Mathematics 2024-01-08 Bilal Ahmad Rather

The concept of gcd-graphs is introduced by Klotz and Sander, which arises as a generalization of unitary Cayley graphs. The gcd-graph $X_n (d_1,...,d_k)$ has vertices $0,1,...,n-1$, and two vertices $x$ and $y$ are adjacent iff…

Combinatorics · Mathematics 2015-03-19 Milan Bašić , Aleksandar Ilić

Let R be a commutative ring with identity and let J be an ideal of R. In this paper, we introduce and investigate the notion of the i-extended ideal-based cozero-divisor graph of R. This graph, denoted by $\overline{\Gamma''}_{Ji}(R)$, is a…

Commutative Algebra · Mathematics 2026-05-08 Faranak Farshadifar

The separation dimension of a hypergraph $G$ is the smallest natural number $d$ for which there is an embedding of $G$ into $\mathbb{R}^d$, such that any pair of disjoint edges is separated by some hyperplane normal to one of the axes. The…

Combinatorics · Mathematics 2021-09-01 Raphael Yuster

The distinguishing number (index) $D(G)$ ($D'(G)$) of a graph $G$ is the least integer $d$ such that $G$ has an vertex labeling (edge labeling) with $d$ labels that is preserved only by a trivial automorphism. In this paper we compute these…

Combinatorics · Mathematics 2016-07-27 Saeid Alikhani , Samaneh Soltani

The zero-divisor graph $\Gamma(R)$ of an associative ring $R$ is the graph whose vertices are all nonzero zero-divisors (one-sided and two-sided) of $R$, and two distinct vertices $x$ and $y$ are joined by an edge iff either $xy=0$ or…

Rings and Algebras · Mathematics 2012-01-18 Yu. N. Maltsev , A. S. Kuzmina

The proper commuting graph $\mathcal{C}^{**}(G)$ of a finite group $G$ is the simple graph whose vertices are the noncentral elements of $G$ and two distinct vertices are adjacent if they commute. In this paper, we study the domination…

Combinatorics · Mathematics 2026-05-07 Sudip Bera , Hiranya Kishore Dey , Umang Jethva

The distinguishing number $D(G)$ of a graph $G$ is the least integer $d$ such that $G$ has a vertex labeling with $d$ labels that is preserved only by a trivial automorphism. The distinguishing stability, of a graph $G$ is denoted by…

Combinatorics · Mathematics 2016-09-26 Saeid Alikhani , Samaneh Soltani

The distinguishing number (index) $D(G)$ ($D'(G)$) of a graph $G$ is the least integer $d$ such that $G$ has an vertex labeling (edge labeling) with $d$ labels that is preserved only by a trivial automorphism. Let $G$ be a connected graph…

Combinatorics · Mathematics 2016-07-26 Samaneh Soltani , Saeid Alikhani

The distinguishing number (index) $D(G)$ ($D'(G)$) of a graph $G$ is the least integer $d$ such that $G$ has an vertex labeling (edge labeling) with $d$ labels that is preserved only by a trivial automorphism. A graphoidal cover of $G$ is a…

Combinatorics · Mathematics 2017-08-22 Saeid Alikhani , Samaneh Soltani

A graph is called uniquely distinguishing colorable if there is only one partition of vertices of the graph that forms distinguishing coloring with the smallest possible colors. In this paper, we study the unique colorability of the…

Combinatorics · Mathematics 2023-08-16 M. Korivand , N. Soltankhah , K. Khashyarmanesh

Let $G$ be a graph of order $n$. A classical upper bound for the domination number of a graph $G$ having no isolated vertices is $\lfloor\frac{n}{2}\rfloor$. However, for several families of graphs, we have $\gamma(G) \le…

Combinatorics · Mathematics 2025-12-09 Subramanian Arumugam , Suresh Manjanath Hegde , Shashanka Kulamarva

In this paper, we continue the program initiated by I. Beck's now classical paper concerning zero-divisor graphs of commutative rings. After the success of much research regarding zero-divisor graphs, many authors have turned their…

Commutative Algebra · Mathematics 2014-01-03 Christopher Park Mooney

A \textit{distinguishing partition} of a group $X$ with automorphism group ${aut}(X)$ is a partition of $X$ that is fixed by no nontrivial element of ${aut}(X)$. In the event that $X$ is a complete multipartite graph with its automorphism…

Combinatorics · Mathematics 2013-01-22 Michael Goff

A subset $D$ of vertices of a graph $G$ is a dominating set if for each $u\in V(G)\setminus D$, $u$ is adjacent to some vertex $v\in D$. The domination number, $\gamma(G)$ of $G$, is the minimum cardinality of a dominating set of $G$. For…

Combinatorics · Mathematics 2018-04-10 Doost Ali Mojdeh , Seyed Reza Musawi , Esmaeil Nazari