Some results on the spectral radius of generalized ∞ and θ-digraphs

Let -digraph be a generalized strongly connected ∞-digraph and let -digraph and -digraph be two kinds of generalized strongly connected θ-digraphs. In this paper, we characterize the extremal digraphs which achieve the maximum and minimum spectral radius among all Administrator in -digraphs and -digraphs. At the same time, we also determine the extremal digraph which achieves the maximum spectral radius among all Administrator in -digraphs. Furthermore, we show that any -digraph is determined by the spectrum.