关于图的Laplacian谱半径的一个改进上界  

An Mproved Upper Bound on Laplacian Spectral Radius of Graphs

作　　者：徐淮涓[1] 

机构地区：[1]淮阴师范学院数学系,江苏淮安223300

出　　处：《淮阴师范学院学报（自然科学版）》2008年第3期202-204,共3页Journal of Huaiyin Teachers College;Natural Science Edition

摘　　要：设G为n阶简单连通图,若L(G)为图G的度对角矩阵与邻接矩阵的差,称L(G)为图G的Laplacian矩阵.本文利用图的度序列平方和与非负矩阵谱理论给出了L(G)的谱半径的一个新上界,改进了现有结果.Let G be a simple connected graph with n vertices. The matrix L （G） is said the Laplacian matrix of G, if it is the difference of the degree diagonal matrix of vertex degrees and the adjacency matrix of G. In this paper, we obtain new upper bounds of spectral radius of Laplacian matrices of graphs by the square sum of the degree sequence of a graph and Spectra theory of non-negative matrix, the result improves previous one.

关 键 词：图 LAPLACIAN矩阵 谱半径 上界 

分 类 号：O157.5[理学—数学]