نتایج جستجو برای: seidel signless laplacian eigenvalues

تعداد نتایج: 31915  

2008
Domingos M. Cardoso Peter Rowlinson Slobodan K. Simić

We prove that the minimum value of the least eigenvalue of the signless Laplacian of a connected nonbipartite graph with a prescribed number of vertices is attained solely in the unicyclic graph obtained from a triangle by attaching a path at one of its endvertices. © 2008 Elsevier Inc. All rights reserved. AMS classification: 05C50

Journal: :Discussiones Mathematicae Graph Theory 2014
Hong-Hai Li Li Su Jing Zhang

In this paper we observe that the minimal signless Laplacian spectral radius is obtained uniquely at the kite graph PKn−ω,ω among all connected graphs with n vertices and clique number ω. In addition, we show that the spectral radius μ of PKm,ω (m ≥ 1) satisfies

Journal: :Graphs and Combinatorics 2015
Zhen-Mu Hong Yi-Zheng Fan

LetB(n, r) be the set of all bicyclic graphs with n vertices and r cut edges. In this paper we determine the unique graph with maximal adjacency spectral radius or signless Laplacian spectral radius among all graphs in B(n, r).

Journal: :Electr. J. Comb. 2012
Muhuo Liu

In this paper, some new properties are presented to the extremal graphs with largest (signless Laplacian) spectral radii in the set of all the connected graphs with prescribed degree sequences, via which we determine all the extremal tricyclic graphs in the class of connected tricyclic graphs with prescribed degree sequences, and we also prove some majorization theorems of tricyclic graphs with...

Journal: :Mathematics 2022

In this paper, we determine the maximum signless Laplacian spectral radius of all graphs which do not contain small books as a subgraph and characterize extremal graphs. addition, give an upper bound intersecting quadrangles subgraph.

Journal: :Linear Algebra and its Applications 2010

2016
Mingzhu Chen Bo Zhou

A cactus is a connected graph in which any two cycles have at most one vertex in common. We determine the unique graphs with maximum signless Laplacian spectral radius in the class of cacti with given number of cycles (cut edges, respectively) as well as in the class of cacti with perfect matchings and given number of cycles.

2017
Shu-Guang Guo Rong Zhang

In this paper, we determine the unique graph whose least signless Laplacian eigenvalue attains the minimum among all non-bipartite unicyclic graphs of order n with maximum degree Δ and among all non-bipartite connected graphs of order n with maximum degree Δ, respectively.

2017
Jun He Yan-Min Liu Jun-Kang Tian Xiang-Hu Liu

In this paper, we give some new sharp upper and lower bounds for the spectral radius of a nonnegative irreducible matrix. Using these bounds, we obtain some new and improved bounds for the signless Laplacian spectral radius of a graph or a digraph.

Journal: :Symmetry 2022

Let D be a digraph with n vertices and arcs. The Laplacian the signless matrices of are, respectively, defined as L(D)=Deg+(D)−A(D) Q(D)=Deg+(D)+A(D), where A(D) represents adjacency matrix Deg+(D) diagonal whose elements are out-degrees in D. We derive combinatorial representation regarding first few coefficients (signless) characteristic polynomial provide concrete directed motifs to highligh...

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