There are two distinct notions of connectivity in a directed graph. A directed graph is weakly
connected if there is an undirected path between any pair of vertices,
and strongly connected if there is a
directed path between every pair of vertices (Skiena 1990, p. 173). The
following tables summarized the number of weakly and strongly connected digraphs
on ,
2, ... nodes. The 8 weakly but not strongly connected digraphs on three nodes are
illustrated above.
,
2, ... nodes. The 8 weakly but not strongly connected digraphs on three nodes are
illustrated above.
