English
Related papers

Related papers: Graphs determined by signless Laplacian spectra

200 papers

The Bridge graph is a special type of graph which are constructed by connecting identical connected graphs with path graphs. We discuss different types of bridge graphs $B_{n\times l}^{m\times k}$ in this paper. In particular, we discuss…

Combinatorics · Mathematics 2023-01-03 Yixin Li

A signed graph is a graph whose edges are labeled either positive or negative. Corresponding to the two signed distance matrices defined for signed graphs, we define two signed distance laplacian matrices. We characterize balance in signed…

Combinatorics · Mathematics 2020-10-12 Roshni T Roy , K A Germina , K Shahul Hameed , Thomas Zaslavsky

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

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

The spectral theory of graphs provides a bridge between classical signal processing and the nascent field of graph signal processing. In this paper, a spectral graph analogy to Heisenberg's celebrated uncertainty principle is developed.…

Information Theory · Computer Science 2013-08-02 Ameya Agaskar , Yue M. Lu

Associative spectra of graph algebras are examined with the help of homomorphisms of DFS trees. Undirected graphs are classified according to the associative spectra of their graph algebras; there are only three distinct possibilities:…

Combinatorics · Mathematics 2021-05-20 Erkko Lehtonen , Tamás Waldhauser

Counting dominating sets in a graph $G$ is closely related to the neighborhood complex of $G$. We exploit this relation to prove that the number of dominating sets $d(G)$ of a graph is determined by the number of complete bipartite…

Combinatorics · Mathematics 2017-01-13 Irene Heinrich , Peter Tittmann

Two signed graphs are called switching isomorphic if one of them is isomorphic to a switching equivalent of the other. To determine the number of switching non-isomorphic signed graphs on a specific graph, we will establish a method based…

Combinatorics · Mathematics 2019-09-17 Yousef Bagheri , Alireza Moghadamfar , Farzaneh Ramezani

Let $G$ be a simple connected graph of order $n$ and $D(G)$ be the distance matrix of $G.$ Suppose that $\lambda_{1}(D(G))\geq\lambda_{2}(D(G))\geq\cdots\geq\lambda_{n}(D(G))$ are the distance spectrum of $G$. A graph $G$ is said to be…

Combinatorics · Mathematics 2015-04-17 Ruifang Liu , Jie Xue , Litao Guo

Let $G$ be a graph with adjacency matrix $A\left( G\right) $, and let $D\left( G\right) $ be the diagonal matrix of the degrees of $G.$ The signless Laplacian $Q\left( G\right) $ of $G$ is defined as $Q\left( G\right) :=A\left( G\right)…

Combinatorics · Mathematics 2016-07-12 V. Nikiforov

The area of Data Analytics on graphs promises a paradigm shift as we approach information processing of classes of data, which are typically acquired on irregular but structured domains (social networks, various ad-hoc sensor networks).…

Information Theory · Computer Science 2019-08-13 Ljubisa Stankovic , Danilo Mandic , Milos Dakovic , Milos Brajovic , Bruno Scalzo , Tony Constantinides

This survey is two-fold. We first report new progress on the spectral extremal results on the Tur\'{a}n type problems in graph theory. More precisely, we shall summarize the spectral Tur\'{a}n function in terms of the adjacency spectral…

Combinatorics · Mathematics 2022-05-13 Yongtao Li , Weijun Liu , Lihua Feng

There is a deep and interesting connection between the topological properties of a graph and the behaviour of the dynamical system defined on it. We analyse various kind of graphs, with different contrasting connectivity or degree…

Combinatorics · Mathematics 2017-05-01 Barbara Giunti , Vincenzo Perri

Spectral features are widely incorporated within Graph Neural Networks (GNNs) to improve their expressive power, or their ability to distinguish among non-isomorphic graphs. One popular example is the usage of graph Laplacian eigenvectors…

Machine Learning · Computer Science 2025-09-29 Snir Hordan , Maya Bechler-Speicher , Gur Lifshitz , Nadav Dym

Given a graph $H$, a graph is said to be $H$-free if it does not contain $H$ as a subgraph. A graph is color-critical when it has an edge whose removal leads to a reduction in its chromatic number. For a graph $H$ with a chromatic number of…

Combinatorics · Mathematics 2025-08-19 Yuantian Yu , Shuchao Li

Given two graphs $H_1$ and $H_2$, a graph is $(H_1,H_2)$-free if it contains no induced subgraph isomorphic to $H_1$ nor $H_2$. A graph $G$ is $k$-vertex-critical if every proper induced subgraph of $G$ has chromatic number less than $k$,…

Combinatorics · Mathematics 2024-03-12 Wen Xia , Jorik Jooken , Jan Goedgebeur , Shenwei Huang

The distance matrix $\mathcal{D}$ of a connected graph $G$ is the matrix indexed by the vertices of $G$ which entry $\mathcal{D}_{i,j}$ equals the distance between the vertices $v_i$ and $v_j$. The distance signless Laplacian matrix…

Combinatorics · Mathematics 2021-04-06 Chang Liu , Jianping Li

Let $D$ be an digraph of order $n$ with adjacency matrix $A(D)$ and outdegree matrix $\Delta^+=\Delta^+(D)$. Then the Laplacian and signless Laplacian matrices of $D$ are respectively defined as $L(D)=\Delta^+-A(D)$ and…

Combinatorics · Mathematics 2026-04-07 Mushtaq A. Bhat , Peer Abdul Manan

The \textit{Kite graph}, denoted by $Kite_{p,q}$ is obtained by appending a complete graph $K_{p}$ to a pendant vertex of a path $P_{q}$. In this paper, firstly we show that no two non-isomorphic kite graphs are cospectral w.r.t adjacency…

Combinatorics · Mathematics 2015-06-05 Sezer Sorgun , Hatice Topcu

The signless Laplacian matrix of a graph $G$ is given by $Q(G)=D(G)+A(G)$, where $D(G)$ is a diagonal matrix of vertex degrees and $A(G)$ is the adjacency matrix. The largest eigenvalue of $Q(G)$ is called the signless Laplacian spectral…

Combinatorics · Mathematics 2021-11-11 Chang Liu , Yingui Pan , Jianping Li