Results 81 to 90 of about 2,420 (96)

Signed graphs with strong (anti-)reciprocal eigenvalue property

Special Matrices
A (signed) graph is said to exhibit the strong reciprocal (anti-reciprocal) eigenvalue property (SR) (resp., (-SR)) if for any eigenvalue λ\lambda , it has 1λ\frac{1}{\lambda } (resp.,−1λ-\frac{1}{\lambda }) as an eigenvalue as well, with the same ...
Belardo Francesco, Huntington Callum
doaj   +1 more source

An Odd Characterization of the Generalized Odd Graphs [PDF]

2010 Mathematics Subject Classification: 05E30, 05C50;distance-regular graphs;generalized odd graphs;odd-girth;spectra of graphs;spectral excess theorem;spectral ...
Dam, E.R. van, Haemers, W.H.
core   +1 more source

On the Laplacian index of tadpole graphs

Special Matrices
In this article, we study the Laplacian index of tadpole graphs, which are unicyclic graphs formed by adding an edge between a cycle Ck{C}_{k} and a path Pn{P}_{n}.
Braga Rodrigo O., Veloso Bruno S.
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Bounds on F-index of tricyclic graphs with fixed pendant vertices

Open Mathematics, 2020
The F-index F(G) of a graph G is obtained by the sum of cubes of the degrees of all the vertices in G. It is defined in the same paper of 1972 where the first and second Zagreb indices are introduced to study the structure-dependency of total π-electron ...
Akram Sana, Javaid Muhammad, Jamal Muhammad   +2 more
doaj   +1 more source

Universal Adjacency Matrices with Two Eigenvalues [PDF]

AMS Mathematics Subject Classification: 05C50.Adjacency matrix;Universal adjacency matrix;Laplacian matrix;signless Laplacian;Graph spectra;Eigenvalues;Strongly regular ...
Haemers, W.H., Omidi, G.R.
core   +1 more source

Some results involving the Aα-eigenvalues for graphs and line graphs

Special Matrices
Let GG be a simple graph with adjacency matrix A(G)A\left(G), degree diagonal matrix D(G),D\left(G), and let l(G)l\left(G) be the line graph of GG. In 2017, Nikiforov defined the Aα{A}_{\alpha }-matrix of GG, Aα(G){A}_{\alpha }\left(G), as a linear ...
da Silva Júnior João Domingos G., Oliveira Carla Silva, da Costa Liliana Manuela G. C.   +2 more
doaj   +1 more source

The Maximum Order of Adjacency Matrices With a Given Rank [PDF]

AMS Subject Classification: 05B20, 05C50.Graph;Adjacency ...
Haemers, W.H., Peeters, M.J.P.
core   +1 more source

A note on the eigenvalue free intervals of some classes of signed threshold graphs

Special Matrices, 2019
We consider a particular class of signed threshold graphs and their eigenvalues. If Ġ is such a threshold graph and Q(Ġ ) is a quotient matrix that arises from the equitable partition of Ġ , then we use a sequence of elementary matrix operations to prove
Anđelić Milica, Koledin Tamara, Stanić Zoran   +2 more
doaj   +1 more source

Uniformity in Association schemes and Coherent Configurations: Cometric Q-Antipodal Schemes and Linked Systems [PDF]

2010 Mathematics Subject Classification.
Dam, E.R. van, Martin, W.J., Muzychuk, M.   +2 more
core   +1 more source

Diagonalizable matrices whose graph is a tree: the minimum number of distinct eigenvalues and the feasibility of eigenvalue assignments

Special Matrices, 2019
Considered are combinatorially symmetric matrices, whose graph is a given tree, in view of the fact recent analysis shows that the geometric multiplicity theory for the eigenvalues of such matrices closely parallels that for real symmetric (and complex ...
Saiago Carlos M.
doaj   +1 more source