Definition:Incident (Graph Theory)/Planar Graph

Definition

 * PlanarGraph.png

Let $G = \struct {V, E}$ be a planar graph:

Then a face of $G$ is incident to an edge $e$ of $G$ if $e$ is one of those which surrounds the face.

Similarly, a face of $G$ is incident to a vertex $v$ of $G$ if $v$ is at the end of one of those incident edges.

In the above graph, for example, the face $ABHC$ is incident to:
 * the edges $AB, BH, HC, CA$
 * the vertices $A, B, H, C$.