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This paper investigates spectral properties of the deformed Laplacian matrix, which merges the Laplacian and signless Laplacian matrices of a graph through a one-parameter family of matrices. We present general results on the eigenvalues of…

Combinatorics · Mathematics 2025-12-04 Roberto C. Díaz , Elismar R. Oliveira , Vilmar Trevisan

The commuting graph of a non-commutative ring $R$ with center $Z(R)$ is a simple undirected graph whose vertex set is $R\setminus Z(R)$ and two vertices $x, y$ are adjacent if and only if $xy = yx$. In this paper, we compute the spectrum…

Spectral Theory · Mathematics 2016-04-12 Jutirekha Dutta , Rajat Kanti Nath

We enumerate the connected graphs that contain a linear number of edges with respect to the number of vertices. So far, only the first term of the asymptotics was known. Using analytic combinatorics, i.e. generating function manipulations,…

Combinatorics · Mathematics 2016-04-26 Elie de Panafieu

We consider a versatile matrix model of the form ${\bf A}+i {\bf B}$, where ${\bf A}$ and ${\bf B}$ are real random circulant matrices with independent but, in general, nonidentically distributed Gaussian entries. For this model, we derive…

Mathematical Physics · Physics 2025-04-29 Sunidhi Sen , Himanshu Shekhar , Santosh Kumar

In this work, we study a mathematically rigorous metric of a graph visualization quality under conditions that relate to visualizing a bipartite graph. Namely we study rectilinear crossing number in a special arrangement of the complete…

Combinatorics · Mathematics 2023-10-25 Mohsen Nafar

The complexity of a graph is the number of its labeled spanning trees. In this work complexity is studied in settings that admit regular graphs. An exact formula is established linking complexity of the complement of a regular graph to…

Combinatorics · Mathematics 2025-08-18 Gregory P Constantine , Gregory Magda

Graphs are commonly used in mathematics to represent some relationships between items. However, as simple objects, they sometimes fail to capture all relevant aspects of real-world data. To address this problem, we generalize them and model…

Social and Information Networks · Computer Science 2019-10-04 Pimprenelle Parmentier , Tiphaine Viard , Benjamin Renoust , Jean-François Baffier

Graph signal processing analyzes signals supported on the nodes of a graph by defining the shift operator in terms of a matrix, such as the graph adjacency matrix or Laplacian matrix, related to the structure of the graph. With respect to…

Signal Processing · Electrical Eng. & Systems 2018-03-01 Stephen Kruzick , José M. F. Moura

Graphlet analysis is an approach to network analysis that is particularly popular in bioinformatics. We show how to set up a system of linear equations that relate the orbit counts and can be used in an algorithm that is significantly…

Data Structures and Algorithms · Computer Science 2017-04-12 Tomaž Hočevar , Janez Demšar

Coordination sequences of periodic and quasiperiodic graphs are analysed. These count the number of points that can be reached from a given point of the graph by a number of steps along its bonds, thus generalising the familiar coordination…

Statistical Mechanics · Physics 2019-07-17 Michael Baake , Uwe Grimm , Przemyslaw Repetowicz , Dieter Joseph

We study a general class of recurrence relations that appear in the application of a matrix diagonalization procedure. We find general closed formula and determine analytical properties of the solutions. We finally apply these findings in…

Combinatorics · Mathematics 2025-07-02 Elismar R. Oliveira , Vilmar Trevisan

We use a well known concept of proper vertex colouring of a graph to introduce the construction of a chromatic completion graph and its related parameter, the chromatic completion number of a graph. We then give the chromatic completion…

General Mathematics · Mathematics 2018-09-06 E. G Mphako-Banda , J. Kok

The spectrum of a graph $G$ is the set of the eigenvalues of its adjacency matrix. It turns out that one can say a lot about a graph with the only knowledge being the spectrum of this graph. In this paper we obtain new results about the…

Combinatorics · Mathematics 2025-10-09 M. Koshelev , A. Raigorodskii

Graphings are special bounded-degree graphs on probability spaces, representing limits of graph sequences that are convergent in a local or local-global sense. We describe a procedure for turning the underlying space into a compact metric…

Combinatorics · Mathematics 2021-02-17 László Lovász

Consider a graph on the non-singular matrices over a finite field, in which two distinct non-singular matrices are joined by an edge whenever their sum is singular. We prove an upper bound for the independence number of this graph. As a…

Combinatorics · Mathematics 2024-05-15 Bogdan Nica

Consider $n$ points distributed uniformly in $[0,1]^d$. Form a graph by connecting two points if their mutual distance is no greater than $r(n)$. This gives a random geometric graph, $\gnrn$, which is connected for appropriate $r(n)$. We…

Probability · Mathematics 2007-05-23 Sanatan Rai

We study cliques in graphs arising from quadratic forms where the vertices are the elements of the module of the quadratic form and two vertices are adjacent if their difference represents some fixed scalar. We determine structural…

Number Theory · Mathematics 2023-06-13 Nico Lorenz , Marc Christian Zimmermann

We introduce a new invariant, the coronal of a graph, and use it to compute the spectrum of the corona $G\circ H$ of two graphs $G$ and $H$. In particular, we show that this spectrum is completely determined by the spectra of $G$ and $H$…

Combinatorics · Mathematics 2011-11-07 Cam McLeman , Erin McNicholas

We study the properties of certain graphs involving the sums of primes. Their structure largely turns out to relate to the distribution of prime gaps and can be roughly seen in Cram\'er's model as well. We also discuss generalizations to…

Number Theory · Mathematics 2021-11-05 Anupam Datta , Nir Elber , Raymond Feng , David Lowry-Duda , Henry Xie

The problem of computation of the joint (generalized) spectral radius of matrix sets has been discussed in a number of publications. In the paper an iteration procedure is considered that allows to build numerically Barabanov norms for the…

Rings and Algebras · Mathematics 2011-03-21 Victor Kozyakin