纺织高校基础科学学报Issue(4)：423-428,435,7.
两类联图的Q（L）谱及有限的Q（L）整图类
Q(L)-spectra of two join graphs and infinite families of Q(L)-integral graphs
摘要
Abstract
Let G be a simple graph .The matrix Q(G)= D(G)+ A(G) is the signless Laplacian matrix of G ,where D(G) and A(G) is the diagonal matrix of vertex degrees and the adjacency matrix of G ,respectively .The Laplacian matrix of G is the matrix L(G)= D(G)-A(G) .A graph iscalled L-integral (resp .Q-integral) if its (signless) Laplacian spectrum consists entire-ly of integers .Let G1 and G2 be two graphs ,and S(G) be the subdivision graph of G .Then the Svertex join of G1 and G2 ,denoted by G1 ∨· G2 is obtained from S(G1 ) and G2 by joining each verti-ces of G1 to each vertices of G2 .The Sedge join of G1 with G2 ,denoted by G1 ∨ G2 is obtained from S(G1 ) and G2 by joining all vertices of S(G1 ) corresponding to the edges of G1 with all vertices of G2 .In this paper we obtain the Q-spectra and L-spectra of these two joins of graphs w hen G1 and G2 are regular graphs . As an application ,some infinite families of Q-integral graphs and L-integral graphs are obtained .关键词
无符号拉普拉斯整图/拉普拉斯整图/图谱/联图Key words
Q-integral graph/L-integral graph/graph spectrum/join of graphs分类
数理科学引用本文复制引用
孙丰妹,王力工..两类联图的Q（L）谱及有限的Q（L）整图类[J].纺织高校基础科学学报,2013,(4):423-428,435,7.基金项目
Supported by the National Natural Science Foundation of China （）
