Bulletin of the
Korean Mathematical Society BKMS

Cho and Kim [4] and Kim [6] introduced the concept of the competition index of a digraph. Cho and Kim [4] and Akelbek and Kirkland [1] also studied the upper bound of competition indices of primitive digraphs. In this paper, we study the upper bound of competition indices of strongly connected digraphs. We also study the relation between competition index and ordinary index for a symmetric strongly connected digraph.

Keywords: competition graph, $m$-step competition graph, competition index, competition period, scrambling index, symmetric digraph

MSC numbers: 05C20, 05C50