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We introduce a switching operation, inspired by the Godsil-McKay switching, in order to obtain pairs of $G$-cospectral gain graphs, that are gain graphs cospectral with respect to every representation of the gain group $G$. For instance,…

Combinatorics · Mathematics 2022-07-25 Matteo Cavaleri , Alfredo Donno , Stefano Spessato

Let $L(G)$ be the set of all subgroups of a group $G$. The subgroup generating bipartite graph $\mathcal{B}(G)$ defined on $G$ is a bipartite graph whose vertex set is partitioned into two sets $G \times G$ and $L(G)$, and two vertices $(a,…

Group Theory · Mathematics 2026-01-08 Shrabani Das , Ahmad Erfanian , Rajat Kanti Nath

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

Graph energy is the energy of the matrix representation of the graph, where the energy of a matrix is the sum of singular values of the matrix. Depending on the definition of a matrix, one can contemplate graph energy, Randi\'c energy,…

Social and Information Networks · Computer Science 2019-02-12 Mikołaj Morzy , Tomasz Kajdanowicz

We introduce a new operation on a class of graphs with the property that the Laplacian eigenvalues of the input and output graphs are related. Based on this operation, we obtain a family of order (square root of n) noncospectral unicyclic…

Combinatorics · Mathematics 2013-04-05 Eliseu Fritscher , Carlos Hoppen , Vilmar Trevisan

In 1978 Gutman introduced the energy of a graph as the sum of the absolute values of graph eigenvalues, and ever since then graph energy has been intensively studied. Since graph energy is the trace norm of the adjacency matrix, matrix…

Combinatorics · Mathematics 2016-05-12 Vladimir Nikiforov

In this paper, we investigate certain graphs defined on groups, with a focus on infinite groups. The graphs discussed are the power graph, the enhanced power graph, and the commuting graph whose vertex set is a group $G$. The power graph is…

Group Theory · Mathematics 2024-10-15 Surbhi , Geetha Venkataraman

In this paper we compute common neighbourhood (abbreviated as CN) spectrum and energy of commuting conjugacy class graph of several families of finite non-abelian groups. As a consequence of our results we show that the commuting conjugacy…

Group Theory · Mathematics 2022-08-23 Firdous Ee Jannat , Rajat Kanti Nath

Graphs can be associated with a matrix according to some rule and we can find the spectrum of a graph with respect to that matrix. Two graphs are cospectral if they have the same spectrum. Constructions of cospectral graphs help us…

Combinatorics · Mathematics 2020-06-02 Kate Lorenzen

The graphs $D(k,q)$ have connected components $CD(k,q)$ giving the best known bounds on extremal problems with {\em forbidden\/} even cycles, and are denser than the well-known graphs of Lubotzky, Phillips, Sarnak and Margulis. Despite…

Combinatorics · Mathematics 2017-01-16 G. Eric Moorhouse , Shuying Sun , Jason Williford

The two graphs of the title both have vertex set G. In the intersection power graph, x and y are joined if some non-identity element is a power of both; in the power graph, x and y joined if one is a power of the other. Thus the power graph…

Combinatorics · Mathematics 2025-09-05 Sudip Bera , Peter J. Cameron

In this paper, we study the energy of semigraphs and obtain some bounds, and show that one of the bounds is tight. We also study the spectra of the adjacency matrix of a special type of rooted 3-uniform semigraph and enumerate those…

Combinatorics · Mathematics 2023-02-24 Ralhad Mohan Shinde , Charusheela Deshpande

We introduce a new class of graphical models that generalizes Lauritzen-Wermuth-Frydenberg chain graphs by relaxing the semi-directed acyclity constraint so that only directed cycles are forbidden. Moreover, up to two edges are allowed…

Machine Learning · Statistics 2018-03-02 Jose M. Peña

Deep learning has been shown to be successful in a number of domains, ranging from acoustics, images, to natural language processing. However, applying deep learning to the ubiquitous graph data is non-trivial because of the unique…

Machine Learning · Computer Science 2020-03-16 Ziwei Zhang , Peng Cui , Wenwu Zhu

Given a graph $G$, we have the adjacency matrix $A(G)$ and degree diagonal matrix $D(G)$. The $Q$-spectrum is the all eigenvalues of $Q$-matrix $Q(G)=A(G)+D(G)$. A class of graphs is determined by their generalized $Q$-spectrum (DGQS for…

Spectral Theory · Mathematics 2023-11-07 Liwen Gao , Xuejun Guo

The $G$-graph $\Gamma(G,S)$ is a graph from the group $G$ generated by $S\subseteq G$, where the vertices are the right cosets of the cyclic subgroups $\langle s \rangle, s\in S$ with $k$-edges between two distinct cosets if there is an…

Combinatorics · Mathematics 2016-09-05 Lord Clifford Kavi

In this paper, we obtain energy, Laplacian energy and signless Laplacian energy of the commuting graphs of some families of finite non-abelian groups.

Group Theory · Mathematics 2017-05-02 Parama Dutta , Rajat Kanti Nath

A signed graph $\Gamma(G)$ is a graph with a sign attached to each of its edges, where $G$ is the underlying graph of $\Gamma(G)$. The energy of a signed graph $\Gamma(G)$ is the sum of the absolute values of the eigenvalues of the…

Combinatorics · Mathematics 2019-01-01 Shuchao Li , Shujing Wang

We consider the Dirac equation on periodic networks (quantum graphs). The self-adjoint quasi periodic boundary conditions are derived. The secular equation allowing us to find the energy spectrum of the Dirac particles on periodic quantum…

Quantum Physics · Physics 2021-08-11 J. R. Yusupov , K. K. Sabirov , D. U. Matrasulov

In this paper, we introduce the concepts of positive and negative $p$-energies of graphs and investigate their behavior under edge addition. Specifically, we generalize the classical notions of positive and negative square energies to the…

Combinatorics · Mathematics 2025-04-09 Quanyu Tang , Yinchen Liu , Wei Wang
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