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Related papers: The strong spectral property for graphs

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A graph $\Gamma$ is $G$-symmetric if it admits $G$ as a group of automorphisms acting transitively on the set of arcs of $\Gamma$, where an arc is an ordered pair of adjacent vertices. Let $\Gamma$ be a $G$-symmetric graph such that its…

Combinatorics · Mathematics 2024-03-05 Teng Fang , Sanming Zhou , Shenglin Zhou

Let $G$ be a group. We define the coprime graph of subgroups of $G$, denoted by $\mathcal P(G)$, is a graph whose vertex set is the set of all proper subgroups of $G$, and two distinct vertices are adjacent if and only if the order of the…

Group Theory · Mathematics 2015-12-08 R. Rajkumar , P. Devi

A graph $G$ is said to be \emph{determined by its spectrum} if any graph having the same spectrum as $G$ is isomorphic to $G$. Let $K_n \setminus P_{\ell}$ be the graph obtained from $K_n$ by removing edges of $P_\ell$, where $P_\ell$ is a…

Combinatorics · Mathematics 2018-04-24 Lihuan Mao , Sebastian M. Cioabă , Wei Wang

The search for a highly discriminating and easily computable invariant to distinguish graphs remains a challenging research topic. Here we focus on cospectral graphs whose complements are also cospectral (generalized cospectral), and on…

Combinatorics · Mathematics 2023-04-17 Aida Abiad , Carlos A. Alfaro , Ralihe R. Villagrán

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

Let $G$ be a connected simple graph on $n$ vertices and $m$ edges. Denote $N_{i}^{(j)}(G)$ the number of spanning subgraphs of $G$ having precisely $i$ edges and not more than $j$ connected components. The graph $G$ is \emph{strong} if…

Combinatorics · Mathematics 2024-12-31 Pablo Romero

A graph H is strongly immersed in G if H is obtained from G by a sequence of vertex splittings (i.e., lifting some pairs of incident edges and removing the vertex) and edge removals. Equivalently, vertices of H are mapped to distinct…

Combinatorics · Mathematics 2014-11-04 Zdenek Dvorak , Paul Wollan

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

Graph learning from data represents a canonical problem that has received substantial attention in the literature. However, insufficient work has been done in incorporating prior structural knowledge onto the learning of underlying…

Machine Learning · Statistics 2019-04-23 Sandeep Kumar , Jiaxi Ying , José Vinícius de M. Cardoso , Daniel Palomar

The spectra of signed matrices have played a fundamental role in social sciences, graph theory, and control theory. In this work, we investigate the computational problems of identifying symmetric signings of matrices with natural spectral…

Discrete Mathematics · Computer Science 2017-07-25 Charles Carlson , Karthekeyan Chandrasekaran , Hsien-Chih Chang , Alexandra Kolla

Let $G$ be an undirected graph on $n$ vertices and let $S(G)$ be the set of all $n \times n$ real symmetric matrices whose nonzero off-diagonal entries occur in exactly the positions corresponding to the edges of $G$. The inverse eigenvalue…

Spectral Theory · Mathematics 2014-01-10 Polona Oblak , Helena Šmigoc

Graph neural networks have developed by leaps and bounds in recent years due to the restriction of traditional convolutional filters on non-Euclidean structured data. Spectral graph theory mainly studies fundamental graph properties using…

Spectral Theory · Mathematics 2023-09-08 Xinye Chen

It is shown how a connected graph and a tree with partially prescribed spectrum can be constructed. These constructions are based on a recent result of Salez that every totally real algebraic integer is an eigenvalue of a tree. Our result…

Combinatorics · Mathematics 2017-01-06 Xueliang Li , Wasin So , Ivan Gutman

Graph classification aims to categorise graphs based on their structure and node attributes. In this work, we propose to tackle this task using tools from graph signal processing by deriving spectral features, which we then use to design…

Machine Learning · Computer Science 2023-06-07 Felix L. Opolka , Yin-Cong Zhi , Pietro Liò , Xiaowen Dong

We study basic spectral features of graph Laplacians associated with a class of rooted trees which contains all regular trees. Trees in this class can be generated by substitution processes. Their spectra are shown to be purely absolutely…

Spectral Theory · Mathematics 2011-01-11 Matthias Keller , Daniel Lenz , Simone Warzel

Series-parallel (SP) graphs are binary edge-labeled graphs with a designated source and target vertex, built using serial and parallel composition. A set of graphs is recognizable if membership depends only on its image under a homomorphism…

Formal Languages and Automata Theory · Computer Science 2026-04-28 Marius Bozga , Radu Iosif , Florian Zuleger

In 2003, van Dam and Haemers posed a fundamental question in spectral graph theory: does there exist a ``sensible'' matrix whose spectrum determines a random graph up to isomorphism? This paper introduces the class of {\em natural graph…

Combinatorics · Mathematics 2026-02-03 Ziqing Xiang

For a graph $G=(V,\ E)$ and a nonempty set $S\subseteq V$, the \emph{vertex boundary} of $S$, denoted by $\partial_G(S)$, is defined to be the set of vertices that are not in $S$ but have at least one neighbor in $S$. In this paper, for $G$…

Combinatorics · Mathematics 2025-10-07 Runze Wang

A realization of a graph $G=(V,E)$ is a map $v\colon V\to\Bbb R^d$ that assigns to each vertex a point in $d$-dimensional Euclidean space. We study graph realizations from the perspective of representation theory (expressing certain…

Combinatorics · Mathematics 2020-09-04 Martin Winter

Recent advent of graph signal processing (GSP) has spurred intensive studies of signals that live naturally on irregular data kernels described by graphs (e.g., social networks, wireless sensor networks). Though a digital image contains…

Image and Video Processing · Electrical Eng. & Systems 2018-01-17 Gene Cheung , Enrico Magli , Yuichi Tanaka , Michael Ng