Document Type : Original paper
University of Qom
The topological ordering algorithm sorts nodes of a directed graph such that the order of the tail of each arc is lower than the order of its head. In this paper, we introduce the notion of covering between nodes of a directed graph. Then, we apply the topological ordering
algorithm on graphs containing the covering nodes. We show that there exists a cut set with
forward arcs in these graphs and the order of the covering nodes is successive.