设G是一个简单无向图,s 3是一个正整数.文章中,若K1,s-匹配数为m(G)的n阶连通图G满足n〉(s+1)m(G),则G的第m(G)大L-特征值μm(G)〉s+1,然后证明了类似结论对于Q-谱也成立.最后给出了几个判断图的哈密顿性的Q-特征值条件.
Let G be a simple graph, and s 3 be an integer. In this paper, if G is a connected graph with order n and K1,s-matching number m(G), such that n (s + 1)m(G),then the m(G)-th largest Laplacian eigenvalue μm(G) s + 1. And this result also holds for signless spectrum. As an application, some Q-eigenvalue conditions which can determine the Hamiltonicity of a graph are listed.