Results 101 to 110 of about 279 (161)

Laplacian spectral radius and some Hamiltonian properties of graphs, manuscript

open access: yes, 2014
. Using upper bounds for the spectral radius of graphs established by Cao, we in this note present sufficient conditions which are based on the spectral radius for some Hamiltonian properties of graphs. Keywords: Spectral radius, Hamiltonian property AMS
Rao Li
core  

Long cycles in 3-connected graphs in orientable surfaces

open access: yes, 2002
In this paper we apply a cutting theorem of Thomassen to show that there is a function f: N → N such that if G is a 3-connected graph which can be embedded in the orientable surface of genus g with face-width at least f(g), then G contains a cycle of ...
Xingxing Yu
core  

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

open access: yesSpecial 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   +2 more
doaj   +1 more source

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

open access: yesSpecial 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.   +2 more
doaj   +1 more source

Zero Forcing Sets and Bipartite Circulants

open access: yes, 2010
In this paper we introduce a class of regular bipartite graphs whose biadja-cency matrices are circulant matrices and we describe some of their properties. Notably, we compute upper and lower bounds for the zero forcing number for such a graph based only
Seth A. Meyer
core  

Eigenvalues of complex unit gain graphs and gain regularity

open access: yesSpecial 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

Spectra of expansion graphs

open access: yes, 1999
. Replace certain edges of a directed graph by chains and consider the eect on the spectrum of the graph. It is shown that the spectral radius decreases monotonically with the expansion and that, for a strongly connected graph that is not a single cycle,
Hans Schneider   +2 more
core   +1 more source

The zero divisor graph of 2 x 2 matrices over a field

open access: yes, 2016
A zero divisor graph, Γ(R), is formed from a ring R by having each element of Z(R)\{0} to be a vertex in the graph and having two vertices u and v adjacent if the corresponding elements from the ring are nonequal and have product equal to zero.
Ashrafi, Ali Reza, Tadayyonfar, Adel
core  

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