Multigraphs, simple graphs, directed multigraphs, directed graphs
- A multigraph is a pseudograph with no loops.
- A simple graph is a pseudograph with no loops and no parallel edges.
- A directed multigraph is defined as a pseudograph, with the difference
that f is now a function from E to the set of ordered pairs of elements
Loops are allowed in directed multigraphs!
- A directed graph is a directed multigraph with no parallel edges.
Again, loops are allowed in directed graphs.
In directed (multi)graphs, edges are drawn as arrows rather than lines.