Topics: Graph - Edge


An arc is a directed edge that joins two vertices together.

Given an arc , the head (denoted ) is the vertex the arrow points to, while the tail (denoted ) is the vertex the arrow points away from.


  • Given a pair of arcs, we may have recurring or parallel arcs.

  • When we have two different arcs that connect a same pair of vertices, but in different directions, we say that they are oppositely directed arcs.

  • A multi-arc is a set of two or more arcs that have the same head or tail. The multiplicity of a multi-arc is the number of arcs involved.