Does it matter whether a line goes from A to B or B to A?
A directed graph gives each edge a direction. A directed graph or digraph is an ordered pair (V, A) with
- a set V whose elements are called vertices or nodes, and
- a set A of ordered pairs of vertices, called arcs, directed edges, or arrows.
A directed graph may be represented by the following nodes and edges.
The set V of vertices is
The set E of edges is
The graph may be uniquely specified as the ordered pair