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For a given graph $H$, its subdivisions carry the same topological structure. The existence of $H$-subdivisions within a graph $G$ has deep connections with topological, structural and extremal properties of $G$. One prominent example of…

Combinatorics · Mathematics 2023-08-22 Seonghyuk Im , Jaehoon Kim , Younjin Kim , Hong Liu

Let $\mathcal{H}$ be a hypergraph with $n$ vertices. Suppose that $d_1,d_2,\ldots,d_n$ are degrees of the vertices of $\mathcal{H}$. The $t$-th graph entropy based on degrees of $\mathcal{H}$ is defined as $$ I_d^t(\mathcal{H})…

Combinatorics · Mathematics 2017-09-28 Dan Hu , Xueliang Li , Xiaogang Liu , Shenggui Zhang

The principal ratio of a graph is the ratio of the greatest and least entry of its principal eigenvector. Since the principal ratio compares the extreme values of the principal eigenvector it is sensitive to outliers. This can be…

Combinatorics · Mathematics 2022-02-02 Gregory J. Clark

A graph homomorphism between two graphs is a map from the vertex set of one graph to the vertex set of the other graph, that maps edges to edges. In this note we study the range of a uniformly chosen homomorphism from a graph G to the…

Probability · Mathematics 2007-06-21 Itai Benjamini , Ariel Yadin , Amir Yehudayoff

A dominating set of a graph $G$ is a set of vertices $D$ such that for all $v \in V(G)$, either $v \in D$ or $(v,d) \in E(G)$ for some $d \in D$. The cardinality redundance of a vertex set $S$, $CR(S)$, is the number of vertices in $V(G)$…

Combinatorics · Mathematics 2019-06-10 Daniel McGinnis , Nathan Shank

Let $G$ be a connected graph of order $n$ with diameter $d$. Remoteness $\rho$ of $G$ is the maximum average distance from a vertex to all others and $\partial_1\geq\cdots\geq \partial_n$ are the distance eigenvalues of $G$. In \cite{AH},…

Combinatorics · Mathematics 2015-07-28 Huiqiu Lin , Kinkar Ch. Das , Baoyindureng Wu

The eccentricity matrix of a graph is obtained from the distance matrix by keeping the largest entries in their row or column, and the remaining entries are replaced by zeros. The eccentricity energy of a graph is the sum of the absolute…

Combinatorics · Mathematics 2026-03-02 Anjitha Ashokan , Chithra A

The cyclic edge-connectivity of a graph $G$ is the least $k$ such that there exists a set of $k$ edges whose removal disconnects $G$ into components where every component contains a cycle. We show that for graphs of minimum degree at least…

Combinatorics · Mathematics 2021-04-07 Sinan G. Aksoy , Mark Kempton , Stephen J. Young

The \textit{eccentricity matrix} $\mathcal{E}(G)$ of a connected graph $G$ is obtained from the distance matrix of $G$ by keeping the largest non-zero entries in each row and each column, and leaving zeros in the remaining ones. The…

Combinatorics · Mathematics 2022-04-01 Iswar Mahato , M. Rajesh Kannan

A graph is $k$-chordal if it does not have an induced cycle with length greater than $k$. We call a graph chordal if it is $3$-chordal. Let $G$ be a graph. The distance between the vertices $x$ and $y$, denoted by $d_{G}(x,y)$, is the…

Combinatorics · Mathematics 2022-10-04 James M Shook , Bing Wei

The metric (resp. edge metric) dimension of a simple connected graph $G$, denoted by dim$(G)$ (resp. edim$(G)$), is the cardinality of a smallest vertex subset $S\subseteq V(G)$ for which every two distinct vertices (resp. edges) in $G$…

Combinatorics · Mathematics 2021-11-25 Enqiang Zhu , Shaoxiang Peng , Chanjuan Liu

We present new values and bounds on the (normalised) closeness centrality $\bar{\mathsf{C}}_C$ of connected graphs and on its product $\bar{l}\bar{\mathsf{C}}_C$ with the mean distance $\bar{l}$ of these graphs. Our main result presents the…

Combinatorics · Mathematics 2023-07-19 Thomas Britz , Xin Hu , Abdellah Islam , Hopein Christofen Tang

Given a regular (connected) graph $\Gamma=(X,E)$ with adjacency matrix $A$, $d+1$ distinct eigenvalues, and diameter $D$, we give a characterization of when its distance matrix $A_D$ is a polynomial in $A$, in terms of the adjacency…

Combinatorics · Mathematics 2019-06-05 M. A. Fiol , Safet Penjić

The vertex (resp. edge) metric dimension of a connected graph G; denoted by dim(G) (resp. edim(G)), is defined as the size of a smallest set S in V (G) which distinguishes all pairs of vertices (resp. edges) in G: Bounds dim(G) <=…

Combinatorics · Mathematics 2021-08-24 Jelena Sedlar , Riste Škrekovski

Recently, it has been proposed that the natural connectivity can be used to efficiently characterise the robustness of complex networks. Natural connectivity quantifies the redundancy of alternative routes in a network by evaluating the…

Statistical Mechanics · Physics 2010-09-20 Jun Wu , Mauricio Barahona , Yuejin Tan , Hongzhong Deng

The edge-connectivity of a graph is the minimum number of edges whose deletion disconnects the graph. Let $\Delta(G)$ the maximum degree of a graph $G$ and let $\rho(G)$ be the spectral radius of $G$. In this article we present a lower…

Combinatorics · Mathematics 2019-11-20 Cristian Conde , Ezequiel Dratman , Luciano N. Grippo

In this paper, we describe primary decomposition of the edge ideal of the join of some graphs in terms of that information of the edge ideal of every weighted oriented graph. Meanwhile, we also study depth and regularity of symbolic powers…

Commutative Algebra · Mathematics 2022-09-15 Yijun Cui , Guangjun Zhu , Xiaoqi Wei

The topological structure of complex networks has fascinated researchers for several decades, resulting in the discovery of many universal properties and reoccurring characteristics of different kinds of networks. However, much less is…

Social and Information Networks · Computer Science 2017-06-28 Yvonne Anne Pignolet , Matthieu Roy , Stefan Schmid , Gilles Tredan

The topological structure of complex networks has fascinated researchers for several decades, resulting in the discovery of many universal properties and reoccurring characteristics of different kinds of networks. However, much less is…

Social and Information Networks · Computer Science 2017-03-02 Yvonne Anne Pignolet , Matthieu Roy , Stefan Schmid , Gilles Tredan

The Zero divisor Graph of a commutative ring $R$, denoted by $\Gamma[R]$, is a graph whose vertices are non-zero zero divisors of $R$ and two vertices are adjacent if their product is zero. Chemical graph theory is a branch of mathematical…

Rings and Algebras · Mathematics 2020-01-07 B. Surendranath Reddy , Rupali S. Jain , N. Laxmikanth