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A hermitian matrix can be parametrized by a set consisting of its determinant and the eigenvalues of its submatrices. We established a group of equations which connect these variables with the mixing parameters of diagonalization. These…

High Energy Physics - Phenomenology · Physics 2024-10-03 S. H. Chiu , T. K. Kuo

We study the gaps between consecutive singular values of random rectangular matrices. Specifically, if $M$ is an $n \times p$ random matrix with independent and identically distributed entries and $\Sigma$ is a $n \times n$ deterministic…

Probability · Mathematics 2025-10-07 Nicholas Christoffersen , Kyle Luh , Sean O'Rourke , Calum Shearer

We introduce a concept of similarity between vertices of directed graphs. Let G_A and G_B be two directed graphs. We define a similarity matrix whose (i, j)-th real entry expresses how similar vertex j (in G_A) is to vertex i (in G_B. The…

Information Retrieval · Computer Science 2007-05-23 Vincent Blondel , Anahi Gajardo , Maureen Heymans , Pierre Senellart , Paul Van Dooren

Typically, graph structures are represented by one of three different matrices: the adjacency matrix, the unnormalised and the normalised graph Laplacian matrices. The spectral (eigenvalue) properties of these different matrices are…

Methodology · Statistics 2020-01-27 J. F. Lutzeyer , A. T. Walden

We consider heuristic algorithm for solving graph isomorphism problem. The algorithm based on a successive splitting of the eigenvalues of the matrices which are modifications (to positive defined) of graphs' adjacency matrices.…

General Mathematics · Mathematics 2007-05-23 R. T. Faizullin , A. V. Prolubnikov

We show how positive unital linear maps can be used to obtain lower bounds for the maximum distance between the eigenvalues of two normal matrices. Some related bounds for the spread and condition number of Hermitian matrices are also…

Functional Analysis · Mathematics 2015-09-21 R. Sharma , R. Kumari

For given k distinct complex conjugate pairs, l distinct real numbers, and a given graph G on 2k+l vertices with a matching of size at least k, we will show that there is a real matrix whose eigenvalues are the given numbers and its graph…

Spectral Theory · Mathematics 2018-03-16 Keivan Hassani Monfared

We characterize the relationship between the singular values of a complex Hermitian (resp., real symmetric, complex symmetric) matrix and the singular values of its off-diagonal block. We also characterize the eigenvalues of an Hermitian…

Algebraic Geometry · Mathematics 2007-05-23 Sergey Fomin , William Fulton , Chi-Kwong Li , Yiu-Tung Poon

A large driver of the complexity of graph learning is the interplay between structure and features. When analyzing the expressivity of graph neural networks, however, existing approaches ignore features in favor of structure, making it…

Machine Learning · Computer Science 2026-03-04 Martin Carrasco , Olga Zaghen , Kavir Sumaraj , Erik Bekkers , Bastian Rieck

We study the spectra of mixed graphs about its Hermitian adjacency matrix of the second kind (i.e. N-matrix) introduced by Mohar [1]. We extend some results and define one new Hermitian adjacency matrix, and the entry corresponding to an…

Combinatorics · Mathematics 2022-06-08 Tao She , Chunxiang Wang

A counter-example to lower bounds for the singular values of the sum of two matrices in [1] and [2] is given. Correct forms of the bounds are pointed out.

General Mathematics · Mathematics 2015-07-24 Sergey Loyka

We prove quadratic eigenvalue perturbation bounds for generalized Hermitian eigenvalue problems. The bounds are proportional to the square of the norm of the perturbation matrices divided by the gap between the spectrums. Using the results…

Numerical Analysis · Mathematics 2010-09-21 Yuji Nakatsukasa

The parameter $q(G)$ of a graph $G$ is the minimum number of distinct eigenvalues of a symmetric matrix whose pattern is given by $G$. We introduce a novel graph product by which we construct new infinite families of graphs that achieve…

Combinatorics · Mathematics 2025-01-09 Eric Culver , Mark Kempton

Since the introduction of the Hermitian adjacency matrix for digraphs, interest in so-called complex unit gain graphs has surged. In this work, we consider gain graphs whose spectra contain the minimum number of two distinct eigenvalues.…

Combinatorics · Mathematics 2021-05-20 Pepijn Wissing , Edwin R. van Dam

The minimum number of distinct eigenvalues, taken over all real symmetric matrices compatible with a given graph $G$, is denoted by $q(G)$. Using other parameters related to $G$, bounds for $q(G)$ are proven and then applied to deduce…

A mixed graph is obtained by orienting some edges of a simple graph. The positive inertia index of a mixed graph is defined as the number of positive eigenvalues of its Hermitian adjacency matrix, including multiplicities. This matrix was…

Combinatorics · Mathematics 2021-02-23 Xiaocong He , Lihua Feng

Arrangement graphs were introduced for their connection to computational networks and have since generated considerable interest in the literature. In a pair of recent articles by Chen, Ghorbani and Wong, the eigenvalues for the adjacency…

Representation Theory · Mathematics 2017-08-16 José Araujo , Tim Bratten

We present a conceptually simple and intuitive method to calculate and to measure the dissimilarities among 2D shapes. Several methods to interpret and to visualize the resulting dissimilarity matrix are presented and compared.

Computer Vision and Pattern Recognition · Computer Science 2022-11-10 Karel Zimmermann

Inspired by the notion of action convergence in graph limit theory, we introduce a measure-theoretic representation of matrices, and we use it to define a new notion of pseudo-metric on the space of matrices. Moreover, we show that such…

Combinatorics · Mathematics 2023-01-05 Raffaella Mulas , Giulio Zucal

In this paper, a new measurement to compare two large-scale graphs based on the theory of quantum probability is proposed. An explicit form for the spectral distribution of the corresponding adjacency matrix of a graph is established. Our…

Discrete Mathematics · Computer Science 2018-07-03 Hayoung Choi , Hosoo Lee , Yifei Shen , Yuanming Shi