Some results on the distance and distance signless Laplacian spectral radius of graphs and digraphs.

Let ρ ( D ( G )) denote the distance spectral radius of a graph G and ∂ ( G → ) denote the distance signless Laplacian spectral radius of a digraph G → . Let G n , k D be the set of all k -connected graphs of order n with diameter D . In this paper, we first determine the unique graph with minimum distance spectral radius in G n , k D ; we then give sharp upper and lower bounds for the distance signless Laplacian spectral radius of strongly connected digraphs; we also characterize the digraphs having the maximal and minimal distance signless Laplacian spectral radii among all strongly connected digraphs; furthermore, we determine the extremal digraph with the minimal distance signless Laplacian spectral radius with given dichromatic number. [ABSTRACT FROM AUTHOR]