图的谱半径及图与补图谱半径和的上界

The spectral radius of a graph and upper bounds on sum of the spectral radius of a graph and its complement

设G为n阶简单图,ρ为G的谱半径,ρ-为补图G-的谱半径。利用代数方法给出了简单图谱半径的新上界和图与其补图谱半径之和的新上界,改进了已有的一些结论。

Let G be a simple graph with n vertices and let p be its spectral radius. Let -↑G be the complement graph of G and let -↑ρ be the spectral radius of -↑G. In this paper, the new upper bound of the spectral radius of G and the new upper bounds on sum of the spectral radius of G and -↑G are given,thus we improve some results which have been given.