Minimum Cuts of Distance-Regular Digraphs

Abstract

In this paper, we show that the edge connectivity of a distance-regular digraph Γ with valency k is k and for k > 2, any minimum edge cut of Γ is the set of all edges going into (or coming out of) a single vertex. Moreover we show that the same result holds for strongly regular digraphs. These results extend the same known results for undirected case with quite different proofs.