There are several types of digraphs:
-
A connected digraph is a digraph where there exists a directed path between every pair of vertices.
-
A simple digraph is a digraph with no loops and no parallel edges.
-
An asymmetric digraph is a digraph with more than one parallel edge, no loops and at least one non-recurring arc.
-
A symmetric digraph is a digraph where there exists a pair of recurring arcs between every connected pair of vertices.
-
A complete digraph is a digraph where there exists a pair of recurring arcs between every pair of vertices.
-
A regular digraph is a digraph where every node has the same internal and external degrees.
-
A balanced digraph is a digraph where every vertex has the same internal and external degree.
-
A pseudodigraph is a digraph that has one or several arcs that join a vertex to itself (a loop arc).
-
A multidigraph is a digraph that can have parallel and recurring arcs, but must not have any loop arcs.