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Applying a method of Godsil and McKay \cite{GM} to some graphs related to the symplectic graph, a series of new infinite families of strongly regular graphs with parameters…

Combinatorics · Mathematics 2016-05-25 Alice M. W. Hui , Bernardo Rodrigues

We consider bounds on maximum nullity of a graph via transversal numbers of compatible collections of forts. Results include generalizations of theorems from symmetric to combinatorially symmetric matrices, special bases of matrix…

Combinatorics · Mathematics 2024-07-08 Veronika Furst , John Hutchens , Lon Mitchell , Yaqi Zhang

Feature learning in the presence of a mixed type of variables, numerical and categorical types, is an important issue for related modeling problems. For simple neighborhood queries under mixed data space, standard practice is to consider…

Machine Learning · Statistics 2020-05-07 Saswata Sahoo , Souradip Chakraborty

Zero forcing is a graph coloring process that is used to model spreading phenomena in real-world scenarios. It can also be viewed as a single-player combinatorial game on a graph, where the player's goal is to select a subset of vertices of…

Combinatorics · Mathematics 2025-09-05 Aida Abiad , Maryam Moghaddas

Despite the tremendous success of graph-based learning systems in handling structural data, it has been widely investigated that they are fragile to adversarial attacks on homophilic graph data, where adversaries maliciously modify the…

Machine Learning · Computer Science 2025-09-05 Yulin Zhu , Yuni Lai , Xing Ai , Wai Lun LO , Gaolei Li , Jianhua Li , Di Tang , Xingxing Zhang , Mengpei Yang , Kai Zhou

The generalized distance matrix of a graph is a matrix in which the $(i,j)$th entry is a function, $f$, of the distance between vertex $i$ and vertex $j$. Depending on the choice of $f$, this family of matrices includes both the adjacency…

Combinatorics · Mathematics 2024-12-10 Ori Friesen , Cecily Kolko , Nick Layman , Kate Lorenzen , Sarah Zaske , Amy Zeigler

In this paper, we study minimal (with respect to inclusion) zero forcing sets. We first investigate when a graph can have polynomially or exponentially many distinct minimal zero forcing sets. We also study the maximum size of a minimal…

Combinatorics · Mathematics 2022-04-18 Boris Brimkov , Joshua Carlson

Graphs with diverse structural characteristics play a central role in modelling and optimization tasks. The ability to generate different types of graphs that exhibit shared properties is likewise essential for algorithm selection and…

Neural and Evolutionary Computing · Computer Science 2026-03-31 Hendrik Richter , Frank Neumann

In this paper, we investigate various algebraic and graph theoretic properties of the distance matrix of a graph. Two graphs are $D$-cospectral if their distance matrices have the same spectrum. We construct infinite pairs of $D$-cospectral…

Given a graph $G=(V,E)$ and a set of vertices marked as filled, we consider a color-change rule known as zero forcing. A set $S$ is a zero forcing set if filling $S$ and applying all possible instances of the color change rule causes all…

Combinatorics · Mathematics 2023-08-16 Eric Ufferman , Nicolas Swanson

Many natural and social systems develop complex networks, that are usually modelled as random graphs. The eigenvalue spectrum of these graphs provides information about their structural properties. While the semi-circle law is known to…

Statistical Mechanics · Physics 2009-11-07 Illes J. Farkas , Imre Derenyi , Albert-Laszlo Barabasi , Tamas Vicsek

We consider the problem of finding universal bounds of "isoperimetric" or "isodiametric" type on the spectral gap of the Laplacian on a metric graph with natural boundary conditions at the vertices, in terms of various analytical and…

Spectral Theory · Mathematics 2016-08-24 James B. Kennedy , Pavel Kurasov , Gabriela Malenova , Delio Mugnolo

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

Let $G$ be a simple graph with a perfect matching. Deng and Zhang showed that the maximum anti-forcing number of $G$ is no more than the cyclomatic number. In this paper, we get a novel upper bound on the maximum anti-forcing number of $G$…

Combinatorics · Mathematics 2023-06-22 Lingjuan Shi , Heping Zhang

We study the effect of external forcing on the saddle-node bifurcation pattern of interval maps. By replacing fixed points of unperturbed maps by invariant graphs, we obtain direct analogues to the classical result both for random forcing…

Dynamical Systems · Mathematics 2011-05-26 Vasso Anagnostopoulou , Tobias Jäger

A gain graph over a group $G$, also referred to as $G$-gain graph, is a graph where an element of a group $G$, called gain, is assigned to each oriented edge, in such a way that the inverse element is associated with the opposite…

Combinatorics · Mathematics 2023-04-10 Aida Abiad , Francesco Belardo , Antonina P. Khramova

A mixed graph contains (undirected) edges as well as (directed) arcs, thus generalizing undirected and directed graphs. A proper coloring $c$ of a mixed graph $G$ assigns a positive integer to each vertex such that $c(u)\neq c(v)$ for every…

Computational Complexity · Computer Science 2026-05-01 Antonio Lauerbach , Konstanty Junosza-Szaniawski , Marie Diana Sieper , Alexander Wolff

Let $G$ be an $n$-vertex graph with adjacency matrix $A$, and $W=[e,Ae,\ldots,A^{n-1}e]$ be the walk matrix of $G$, where $e$ is the all-one vector. In Wang [J. Combin. Theory, Ser. B, 122 (2017): 438-451], the author showed that any graph…

Combinatorics · Mathematics 2021-08-10 Wei Wang , Wei Wang , Tao Yu

This paper explores interlacing inequalities in the Laplacian spectrum of signed cycles and investigates interlacing relationship between the spectrum of the net-Laplacian of a signed graph and its subgraph formed by removing a vertex…

Combinatorics · Mathematics 2023-10-19 Satyam Guragain , Ravi Srivastava

The work in this thesis concerns the investigation of eigenvalues of the Laplacian matrix, normalized Laplacian matrix, signless Laplacian matrix and distance signless Laplacian matrix of graphs. In Chapter 1, we present a brief…

Combinatorics · Mathematics 2021-07-21 Bilal A. Rather
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