A mixed graph in which both directed and undirected edges may exist.
If only directed edges exist, the graph is called a directed graph.
If only undirected edges exist, it is called an undirected graph.
Mixed Graph
See also
Directed Graph, Multigraph, Pseudograph, Simple Graph, Undirected GraphExplore with Wolfram|Alpha
Cite this as:
Weisstein, Eric W. "Mixed Graph." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/MixedGraph.html