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The zero-divisor graph $\Gamma(R)$ of a ring $R$ is a graph with nonzero zero-divisors of $R$ as vertices and distinct vertices $x,y$ are adjacent if $xy=0$ or $yx=0$. We provide an equivalence relation on a ring $R$ and express $\Gamma(R)$…

Spectral Theory · Mathematics 2022-04-01 Krishnat D. Masalkar , Anil Khairnar , Anita Lande , Avinash Patil

The eccentricity matrix $\mathcal E(G)$ of a connected graph $G$ is obtained from the distance matrix of $G$ by leaving unchanged the largest nonzero entries in each row and each column, and replacing the remaining ones with zeros. In this…

Combinatorics · Mathematics 2022-09-13 Xiaohong Li , Jianfeng Wang , Maurizio Brunetti

The eccentricity matrix $\varepsilon(G)$ of a graph $G$ is constructed from the distance matrix of $G$ by keeping only the largest distances for each row and each column. This matrix can be interpreted as the opposite of the adjacency…

Combinatorics · Mathematics 2021-04-26 Xiaocong He

A complex unit gain graph ($ \mathbb{T} $-gain graph), $ \Phi=(G, \varphi) $ is a graph where the function $ \varphi $ assigns a unit complex number to each orientation of an edge of $ G $, and its inverse is assigned to the opposite…

Combinatorics · Mathematics 2025-07-30 Aniruddha Samanta , Deepshikha

We investigate quantum graphs with infinitely many vertices and edges without the common restriction on the geometry of the underlying metric graph that there is a positive lower bound on the lengths of its edges. Our central result is a…

Mathematical Physics · Physics 2018-10-30 Pavel Exner , Aleksey Kostenko , Mark Malamud , Hagen Neidhardt

We develop eigenvalue estimates for the Laplacians on discrete and metric graphs using different types of boundary conditions at the vertices of the metric graph. Via an explicit correspondence of the equilateral metric and discrete graph…

Spectral Theory · Mathematics 2008-04-08 Olaf Post , Fernando Lledo

Spectral features are widely incorporated within Graph Neural Networks (GNNs) to improve their expressive power, or their ability to distinguish among non-isomorphic graphs. One popular example is the usage of graph Laplacian eigenvectors…

Machine Learning · Computer Science 2025-09-29 Snir Hordan , Maya Bechler-Speicher , Gur Lifshitz , Nadav Dym

The spectral properties of signed directed graphs, which may be naturally obtained by assigning a sign to each edge of a directed graph, have received substantially less attention than those of their undirected and/or unsigned counterparts.…

Combinatorics · Mathematics 2021-10-12 Pepijn Wissing , Edwin R. van Dam

The distance energy of a graph $G$ is a recently developed energy-type invariant, defined as the sum of absolute values of the eigenvalues of the distance matrix of $G$. There was a vast research for the pairs and families of non-cospectral…

Combinatorics · Mathematics 2011-04-07 Aleksandar Ili\' c

We study the spectral gap of the Erd\H{o}s--R\'enyi random graph through the connectivity threshold. In particular, we show that for any fixed $\delta > 0$ if $$p \ge \frac{(1/2 + \delta) \log n}{n},$$ then the normalized graph Laplacian of…

Combinatorics · Mathematics 2019-07-16 Christopher Hoffman , Matthew Kahle , Elliot Paquette

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

Let $R$ be a commutative ring with unity. The essential ideal graph $\mathcal{E}_R$ of $R$ is a graph in which the vertex set comprises of set of all nonzero proper ideals of $R$ and two vertices $I$ and $K$ are adjacent if and only if…

Commutative Algebra · Mathematics 2023-10-18 P. Jamsheena , A. V. Chithra

Let $\varepsilon(G)$ be the eccentricity matrix of a graph $G$ and $Spec(\varepsilon(G))$ be the eccentricity spectrum of $G$. Let $H[G_1,G_2,\ldots, G_k]$ be the $H$-join of graphs $G_1,G_2,\ldots, G_k$ and let $H[G]$ be lexicographic…

Combinatorics · Mathematics 2024-10-18 S. Balamoorthy , T. Kavaskar

This article investigates multiset dimensions in zero divisor graphs (ZD-graphs) associated with rings. Through rigorous analysis, we establish general bounds for the multiset dimension (Mdim) in ZD-graphs, exploring various commutative…

Combinatorics · Mathematics 2024-06-24 Nasir Ali , Hafiz Muhammad Afzal Siddiqui , Muhammad Imran Qureshi

This paper surveys some recent results and progress on the extremal prob- lems in a given set consisting of all simple connected graphs with the same graphic degree sequence. In particular, we study and characterize the extremal graphs…

Combinatorics · Mathematics 2015-10-08 Xiao-Dong Zhang

Graph matrices are a type of matrix which has played a crucial role in analyzing the sum of squares hierarchy on average case problems. However, except for rough norm bounds, little is known about graph matrices. In this paper, we take a…

Combinatorics · Mathematics 2024-06-26 Wenjun Cai , Aaron Potechin

The power graph \( \mathcal{G}_G \) of a group \( G \) is a graph whose vertex set is \( G \), and two elements \( x, y \in G \) are adjacent if one is an integral power of the other. In this paper, we determine the adjacency, Laplacian,…

Spectral Theory · Mathematics 2025-05-06 Basit Auyoob Mir , Fouzul Atik , Priti Prasanna Mondal

In this paper, we consider the distance spectra of the derangement graphs. First we give a constructive proof that the connected derangement graphs are of diameter 2. Then we obtain their distance spectra. In particular, we determine all…

Combinatorics · Mathematics 2016-10-24 Yunnan Li , Huiqiu Lin

We study random graphs with arbitrary distributions of expected degree and derive expressions for the spectra of their adjacency and modularity matrices. We give a complete prescription for calculating the spectra that is exact in the limit…

Social and Information Networks · Computer Science 2013-02-04 Raj Rao Nadakuditi , M. E. J. Newman

The aim of this article is to give a simple geometric condition that guarantees the existence of spectral gaps of the discrete Laplacian on periodic graphs. For proving this, we analyse the discrete magnetic Laplacian (DML) on the finite…

Combinatorics · Mathematics 2018-08-08 John Stewart Fabila-Carrasco , Fernando Lledó , Olaf Post