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Related papers: On the normalized spectrum of threshold graphs

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An efficient algorithm is presented to compute the characteristic polynomial of a threshold graph. Threshold graphs were introduced by Chv\'atal and Hammer, as well as by Henderson and Zalcstein in 1977. A threshold graph is obtained from a…

Data Structures and Algorithms · Computer Science 2015-03-03 Martin Fürer

This paper addresses the challenge of spectral analysis and structural investigation for graphs that are not distance-regular, where computing the spectrum using standard methods based on equitable and orbit partitions can be complex. Our…

Combinatorics · Mathematics 2025-11-26 Ali Zafari , Saeid Alikhani

We show that, in the graph spectrum of the normalized graph Laplacian on trees, the eigenvalue 1 and eigenvalues near 1 are strongly related to minimum vertex covers. In particular, for the eigenvalue 1, its multiplicity is related to the…

Combinatorics · Mathematics 2012-06-20 Hao Chen , Jürgen Jost

A complex unit gain graph ($ \mathbb{T} $-gain graph), $ \Phi=(G, \varphi) $ is a graph where the gain 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 2023-12-29 Aniruddha Samanta , M. Rajesh Kannan

In this paper, we introduce a matrix for a mixed graph, called the integrated adjacency matrix. This matrix uniquely determines a mixed graph, as long as the indices of the matrix are specified. Additionally, we associate an (undirected)…

Combinatorics · Mathematics 2025-11-27 G. Kalaivani , R. Rajkumar

We present the spectrum of the (normalized) graph Laplacian as a systematic tool for the investigation of networks, and we describe basic properties of eigenvalues and eigenfunctions. Processes of graph formation like motif joining or…

Adaptation and Self-Organizing Systems · Physics 2012-10-19 Anirban Banerjee , Jürgen Jost

The power graph $\mathscr{P}(G)$ of a group $G$ is an undirected graph with all the elements of $G$ as vertices and where any two vertices $u$ and $v$ are adjacent if and only if $u=v^m $ or $v=u^m$, $ m \in$ $\mathbb{Z}$. For a simple…

Combinatorics · Mathematics 2023-07-19 Komal Kumari , Pratima Panigrahi

We investigate the spectrum of the non-backtracking matrix of a graph. In particular, we show how to obtain eigenvectors of the non-backtracking matrix in terms of eigenvectors of a smaller matrix. Furthermore, we find an expression for the…

Combinatorics · Mathematics 2020-11-19 Cory Glover , Mark Kempton

We derive the limiting distribution for the largest eigenvalues of the adjacency matrix for a stochastic blockmodel graph when the number of vertices tends to infinity. We show that, in the limit, these eigenvalues are jointly multivariate…

Machine Learning · Statistics 2018-04-02 Minh Tang

Any directed graph G with N vertices and J edges has an associated line-graph L(G) where the J edges form the vertices of L(G). We show that the non-zero eigenvalues of the adjacency matrices are the same for all graphs of such a family…

Chaotic Dynamics · Physics 2007-05-23 Prot Pakonski , Gregor Tanner , Karol Zyczkowski

In these paper we study the adjacency matrix of some infinite graphs, which we call the shift operator on the $L^p$ space of the graph. In particular, we establish norm estimates, we find the norm for some cases, we decide the triviality of…

Functional Analysis · Mathematics 2020-01-29 Aahan Agrawal , Astrid Berge , Seth Colbert-Pollack , Rubén A. Martínez-Avendaño , Elyssa Sliheet

An approach to the enumeration of feasible parameters for strongly regular graphs is described, based on the pair of structural parameters (a,c) and the positive eigenvalue e. The Krein bound ensures that there are only finitely many…

Combinatorics · Mathematics 2011-06-07 Norman Biggs

In recent work on equiangular lines, Jiang, Tidor, Yuan, Zhang, and Zhao showed that a connected bounded degree graph has sublinear second eigenvalue multiplicity. More generally they show that there cannot be too many eigenvalues near the…

Probability · Mathematics 2024-01-17 Mikolaj Fraczyk , Ben Hayes , Madhu Sudan , Yufei Zhao

This paper develops the exact linear relationship between the leading eigenvector of the unnormalized modularity matrix and the eigenvectors of the adjacency matrix. We propose a method for approximating the leading eigenvector of the…

Machine Learning · Statistics 2023-10-02 Hansi Jiang , Carl Meyer

The eccentricity matrix $\varepsilon(G)$ of a graph $G$ is obtained from the distance matrix by retaining the eccentricities (the largest distance) in each row and each column. In this paper, we give a characterization of the star graph,…

Combinatorics · Mathematics 2019-09-13 Iswar Mahato , R. Gurusamy , M. Rajesh Kannan , S. Arockiaraj

Let $G$ be a connected graph on $n$ vertices, and let $D(G)$ be the distance matrix of $G$. Let $\partial_1(G)\ge\partial_2(G)\ge\cdots\ge\partial_n(G)$ denote the eigenvalues of $D(G)$. In this paper, we characterize all connected graphs…

Combinatorics · Mathematics 2017-08-29 Xueyi Huang , Qiongxiang Huang , Lu Lu

The extended adjacency matrix of a graph with $n$ vertices is a real symmetric matrix of order $n\times n$ whose $(i,j)$-th entry is the average of the ratio of the degree of the vertex $i$ to that of the vertex $j$ and its reciprocal when…

Combinatorics · Mathematics 2025-01-22 Abujafar Mandal , Sk. Md. Abu Nayeem

We present a finer quantitative version of an observation due to Breuillard, Green, Guralnick and Tao which tells that for finite non-bipartite Cayley graphs, once the nontrivial eigenvalues of their normalized adjacency matrices are…

Combinatorics · Mathematics 2023-11-01 Wenbo Li , Shiping Liu

Given a simple graph $G$, its $A_\alpha$ matrix is a convex combination with parameter $\alpha\in [0,1]$ of its adjacency matrix and its degree diagonal matrices. Here we compare two lower bounds presented in [J. D. G. Silva Jr., C. S.…

Combinatorics · Mathematics 2026-01-27 Giovanni Barbarino

In this work, we discuss some properties of the eigenvalues of some classes of signed complete graphs. We also obtain the form of characteristic polynomial for these graphs.

Combinatorics · Mathematics 2023-09-12 Prajnanaswaroopa S