For questions about directed graphs. In a directed graph, each edge is an ordered pair of vertices; we think of it as pointing from one to the other. Use with the (graph-theory) tag.

Directed graphs, or digraphs, are used to represent asymmetric relationships between a collection of objects.

Formally, a directed graph is defined as consisting of:

- a set of
*vertices*; - set of ordered pairs of vertices, called
*arcs*or*directed edges*.

In diagrams, vertices are represented by points, and each directed edge is represented by an arrow from its first vertex to its second.

Some special classes of directed graphs include:

- Tournaments: directed graphs in which, for every pair of vertices, an edge exists in exactly one direction between them.
- Directed acyclic graphs (DAGs), which contain no directed cycles.