Results 1 to 10 of about 2,420 (96)

Enumeration of Cospectral Graphs [PDF]

AMS classification: 05C50;graphs;eigenvalues ...
Haemers, W.H., Spence, E.
core   +1 more source

A Lower Bound for the Spectral Radius of Graphs with Fixed Diameter [PDF]

AMS classifications: 05C50, 05E99;graphs;spectral radius;diameter;bound;degree ...
Cioaba, S.M., Dam, E.R. van, Koolen, J.H., Lee, J.H.   +3 more
core   +1 more source

Some spectral bounds for the harmonic matrix

Analele Stiintifice ale Universitatii Ovidius Constanta: Seria Matematica, 2017
The aim of this note is to establish new spectral bounds for the harmonic matrix.
Das Kinkar Ch., Fonseca Carlos M. da
doaj   +1 more source

The Minimal Spectral Radius of Graphs with a Given Diameter [PDF]

AMS classsifications: 05C50; 05E99; 94C15;graphs;spectral radius;diameter;networks;virus ...
Dam, E.R. van, Kooij, R.E.
core   +1 more source

Connected graphs cospectral with a Friendship graph

, 2014
Let $n$ be any positive integer, the friendship graph $F_n$ consist of $n$ edge-disjoint triangles that all of them meeting in one vertex. A graph $G$ is called cospectral with a graph $H$ if their adjacency matrices have the same eigenvalues.
Abdollahi, Alireza, Janbaz, Shahrooz
core   +1 more source

The location of classified edges due to the change in the geometric multiplicity of an eigenvalue in a tree

Special Matrices, 2019
Given a combinatorially symmetric matrix A whose graph is a tree T and its eigenvalues, edges in T can be classified in four categories, based upon the change in geometric multiplicity of a particular eigenvalue, when the edge is removed.
Toyonaga Kenji
doaj   +1 more source

Spectra of R-Vertex Join and R-Edge Join of Two Graphs

Discussiones Mathematicae - General Algebra and Applications, 2018
The R-graph R(G) of a graph G is the graph obtained from G by intro- ducing a new vertex ue for each e ∈ E(G) and making ue adjacent to both the end vertices of e. In this paper, we determine the adjacency, Lapla- cian and signless Laplacian spectra of R-
Das Arpita, Panigrahi Pratima
doaj   +1 more source

Note on the product of the largest and the smallest eigenvalue of a graph

Special Matrices
In this note, we use eigenvalue interlacing to derive an inequality between a graph’s maximum degree and its maximum and minimum adjacency eigenvalues. The equality case is fully characterized.
Abiad Aida, Dalfó Cristina, Fiol Miquel Àngel   +2 more
doaj   +1 more source

On the minimum spectral radius of connected graphs of given order and size

Special Matrices
In this article, we study a question of Hong from 1993 related to the minimum spectral radii of the adjacency matrices of connected graphs of given order and size.
Cioaba Sebastian M., Gupta Vishal, Marques Celso   +2 more
doaj   +1 more source

Eigenvalues of complex unit gain graphs and gain regularity

Special Matrices
A complex unit gain graph (or T{\mathbb{T}}-gain graph) Γ=(G,γ)\Gamma =\left(G,\gamma ) is a gain graph with gains in T{\mathbb{T}}, the multiplicative group of complex units.
Brunetti Maurizio
doaj   +1 more source