Abstract :
It is known that the directed cycle of order n uniquely achieves the minimum spectral
radius among all strongly connected digraphs of order n≥3.
In this paper, among others, we determine the digraphs which achieve the second, the third
and the fourth minimum spectral radii respectively among strongly connected
digraphs of order n≥4.
Keywords :
Spectral radius , strongly connected digraph , nonnegative irreducible matrix , bicyclic digraph
