Results 11 to 20 of about 306 (150)
Spectral Sufficient Conditions on Pancyclic Graphs
Complexity, 2021 A pancyclic graph of order n is a graph with cycles of all possible lengths from 3 to n. In fact, it is NP-complete that deciding whether a graph is pancyclic.
Guidong Yu +3 more
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On Extremal Spectral Radii of Uniform Supertrees with Given Independence Number
Discrete Dynamics in Nature and Society, 2022 A supertree is a connected and acyclic hypergraph. Denote by Tm,n,α the set of m-uniform supertrees of order n with independent number α. Focusing on the spectral radius in Tm,n,α, this present completely determines the hypergraphs with maximum spectral ...
Lei Zhang, Haizhen Ren
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Signless Laplacian spectral radius and fractional matchings in graphs [PDF]
, 2017 A {\it fractional matching} of a graph $G$ is a function $f$ giving each edge a number in $[0,1]$ so that $\sum_{e\in (v)}f(e)\leq 1$ for each $v\in V(G)$, where $ (v)$ is the set of edges incident to $v$. The {\it fractional matching number} of $G$, written $ '_{*}(G)$, is the maximum of $\sum_{e\in E(G)}f(e)$ over all fractional matchings $f$. In
Ruifang Liu, Yu Lu
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Signless Laplacian spectral radius for a k-extendable graph [PDF]
Filomat, 2023 Let k and n be two nonnegative integers with n ? 0 (mod 2), and let G be a graph of order n with a perfect matching. Then G is said to be k-extendable for 0 ? k ? n?2/2 if every matching in G of size k can be extended to a perfect matching. In this paper, we first establish a lower bound on the signless Laplacian spectral radius of G to ensure that G ...
Sizhong Zhou, Yuli Zhang
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Signless Laplacian Spectral Conditions for Hamiltonicity of Graphs
Journal of Applied Mathematics, 2014 We establish some signless Laplacian spectral radius conditions for a graph to be Hamiltonian or traceable or Hamilton-connected.
Guidong Yu +3 more
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Distance signless Laplacian spectral radius and Hamiltonian properties of graphs [PDF]
Linear and Multilinear Algebra, 2016 In this paper, first, we establish a sufficient condition for a bipartite graph to be Hamilton-connected. Furthermore, we also give two sufficient conditions on distance signless Laplacian spectral radius for a graph to be Hamilton-connected and traceable from every vertex, respectively.
Qiannan Zhou, Ligong Wang
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On the Signless Laplacian Spectral Radius of Cacti
Croatica Chemica Acta, 2016 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.
Mingzhu Chen, Bo Zhou
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The spectral radius of signless Laplacian matrix and sum-connectivity index of graphs
AKCE International Journal of Graphs and Combinatorics, 2022 The sum-connectivity index of a graph G is defined as the sum of weights [Formula: see text] over all edges uv of G, where du and dv are the degrees of the vertices u and v in G, respectively.
A. Jahanbani, S. M. Sheikholeslami
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Domination number and (signless Laplacian) spectral radius of cactus graphs
The Electronic Journal of Linear AlgebraA cactus graph is a connected graph whose block is either an edge or a cycle. A vertex set $S\subseteq V(G)$ is said to be a dominating set of a graph $G$ if every vertex in $V(G)\setminus S$ is adjacent to a vertex in $S$. There are several results on the (signless Laplacian) spectral radius and domination number in graph theory.
Ye Cui, Yuanyuan Chen, Dan Li, Yue Zhang
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Sharp Upper Bounds on the Signless Laplacian Spectral Radius of Strongly Connected Digraphs
Discussiones Mathematicae Graph Theory, 2016 Let G = (V (G),E(G)) be a simple strongly connected digraph and q(G) be the signless Laplacian spectral radius of G. For any vertex vi ∈ V (G), let d+i denote the outdegree of vi, m+i denote the average 2-outdegree of vi, and N+i denote the set of out ...
Xi Weige, Wang Ligong
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