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In this paper, we study the graph isomorphism and graph automorphism problems. We propose a novel technique to analyze graph isomorphism and graph automorphism. Further we handled some strongly regular datasets for prove the efficiency of…

Combinatorics · Mathematics 2019-06-19 Sivakumar Karunakaran , Lavanya Selvaganesh

A graph $G = (V, E)$ of bounded degree has an adjacency operator~$A$ which acts on the Hilbert space $\ell^2(V)$. There are different kinds of measures of interest on the spectrum $\Sigma (A)$ of $A$. In particular, each vector $\xi \in…

Combinatorics · Mathematics 2023-08-14 Claire Bruchez , Pierre de la Harpe , Tatiana Nagnibeda

In a labeling scheme the vertices of a given graph from a particular class are assigned short labels such that adjacency can be algorithmically determined from these labels. A representation of a graph from that class is given by the set of…

Computational Complexity · Computer Science 2018-02-09 Maurice Chandoo

To a given nonsingular triangular matrix A with entries from a ring, we associate a weighted bipartite graph G(A) and give a combinatorial description of the inverse of A by employing paths in G(A). Under a certain condition, nonsingular…

Combinatorics · Mathematics 2013-03-12 Ravindra Bapat , Ebrahim Ghorbani

A strong clique in a graph is a clique intersecting all inclusion-maximal stable sets. Strong cliques play an important role in the study of perfect graphs. We study strong cliques in the class of diamond-free graphs, from both structural…

In this paper, we introduce a graph structure, called non-zero component graph on finite dimensional vector spaces. We show that the graph is connected and find its domination number and independence number. We also study the…

General Mathematics · Mathematics 2021-11-09 Angsuman Das

The correspondence between weighted undirected graphs and reversible Markov chains via vertex random walks is simple and well known. Leveraging this correspondence and ideas from the theory of dynamical systems, we study the structural…

Statistics Theory · Mathematics 2026-05-12 Yang Xiang , Kevin McGoff , Andrew B. Nobel

Let $G$ be a non-Engel group and let $L(G)$ be the set of all left Engel elements of $G$. Associate with $G$ a graph $\mathcal{E}_G$ as follows: Take $G\backslash L(G)$ as vertices of $\mathcal{E}_G$ and join two distinct vertices $x$ and…

Group Theory · Mathematics 2007-08-16 Alireza Abdollahi

Haemers conjectures that almost all graphs are determined by their spectra. Suppose $G \sim \mathcal{G}(n, p)$ is a random graph with each edge chosen independently with probability $p$ with $0 < p < 1$. Then $$\Pr(G \text{ is not…

Combinatorics · Mathematics 2025-09-09 Wei Wang , Da Zhao

This paper investigates the computational complexity of deciding whether the vertices of a graph can be partitioned into a disjoint union of cliques and a triangle-free subgraph. This problem is known to be $\NP$-complete on arbitrary…

Discrete Mathematics · Computer Science 2014-04-10 Carl Feghali , Faisal N. Abu-Khzam , Haiko Müller

We systematically study a natural problem in extremal graph theory, to minimize the number of edges in a graph with a fixed number of vertices, subject to a certain local condition: each vertex must be in a copy of a fixed graph $H$. We…

Combinatorics · Mathematics 2020-06-24 Debsoumya Chakraborti , Po-Shen Loh

Given a graph $G=(V,E)$, a set of vertices $D\subseteq V $ is called a dominating set if every vertex in $V\backslash D$ is adjacent to a vertex in $D$, and a subset $B\subseteq V $ is called a nonblocking set if $V-B$ is a dominating set.…

Combinatorics · Mathematics 2022-06-07 Mehmet Akif Erdal

We characterize unicyclic graphs that are singular using the support of the null space of their pendant trees. From this, we obtain closed formulas for the independence and matching numbers of a unicyclic graph, based on the support of its…

For any graph $G$ on $n$ vertices and for any {\em symmetric} subgraph $J$ of $K_{n,n}$, we construct an infinite sequence of graphs based on the pair $(G,J)$. The First graph in the sequence is $G$, then at each stage replacing every…

Combinatorics · Mathematics 2013-10-10 Kiran B. Chilakamarri , M. F. Khan , C. E. Larson , C. J. Tymczak

Circulant graphs are a widely studied family of graphs whose members possess varying amounts of symmetry. Although considerable progress has been made in finding the automorphism groups of circulant graphs under certain restrictions, a…

Combinatorics · Mathematics 2026-05-15 Sally Cockburn , Ryhory Hatavets , Will Swartz

The divisorial gonality of a graph is the minimum degree of a positive rank divisor on that graph. We introduce the multiplicity-free gonality of a graph, which restricts our consideration to divisors that place at most \(1\) chip on each…

Combinatorics · Mathematics 2021-07-28 Frances Dean , Max Everett , Ralph Morrison

In a graph G, the cardinality of the smallest ordered set of vertices that distinguishes every element of V (G) (resp. E(G)) is called the vertex (resp. edge) metric dimension of G. In [16] it was shown that both vertex and edge metric…

Combinatorics · Mathematics 2021-04-02 Jelena Sedlar , Riste Škrekovski

Given a graph $G$ with vertices $\{v_1,\ldots,v_n\}$, we define $\mathcal{S}(G)$ to be the set of symmetric matrices $A=[a_{i,j}]$ such that for $i\ne j$ we have $a_{i,j}\ne 0$ if and only if $v_iv_j\in E(G)$. Motivated by the Graph…

Combinatorics · Mathematics 2022-07-18 Craig Erickson , Luyining Gan , Jürgen Kritschgau , Jephian C. -H. Lin , Sam Spiro

We call a pair of non-adjacent vertices in G a non-edge. Contraction of a non-edge {u, v} in G is the replacement of u and v with a single vertex z and then making all the vertices that are adjacent to u or v adjacent to z. A non-edge {u,…

Combinatorics · Mathematics 2025-05-14 Shuai Kou , Chengfu Qin , Weihua Yang , Mingzu Zhang

A graph G is intrinsically S^1-linked if for every embedding of the vertices of G into S^1, vertices that form the endpoints of two disjoint edges in G form a non-split link in the embedding. We show that a graph is intrinsically S^1-linked…

Geometric Topology · Mathematics 2007-07-25 Chris Cicotta , Joel Foisy , Tom Reilly , Sara Revzi , Ben Wang , Alice Wilson