Incidence (graph)

In graph theory, a vertex is incident to an edge if the vertex is one of the two vertices the edge connects.

An incidence is a pair $(u,e)$ where $u$ is a vertex and $e$ is an edge incident to $u$

Two distinct incidences $(u,e)$ and $(v,f)$ are adjacent if and only if $u=v$, $e=f$ or $uv=e$ or $f$.

An incidence coloring of a graph $G$ is an assignment of a color to each incidence of G in such a way that adjacent incidences get distinct colors. It is equivalent to a strong edge coloring of the graph obtained by subdivising each edge of $G$ once.

References

|The Incidence Coloring Page, by Éric Sopena.