Laplace矩阵的谱半径一直是近年来谱图理论的研究热点.本文主要讨论有向图Laplace矩阵的谱半径,用顶点的出度和公共邻域数给出了谱半径上界,用图的最大出度给出了一些特殊图类谱半径的下界.
This paper mainly discuss the spectral radius of the Laplacian matrix of a digraph, and gives upper bounds for the spectral radius in terms of the out-degree and the number of common neighbors of two vertices, and also gives a lower bound for the spectral radius in terms of the maximum degree for some special classes of graph.