# Definition:Loop (Graph Theory)

## Definition

Let $G = \left({V, E}\right)$ be a loop-graph.

A loop is an edge $e$ of $G$ whose endvertices are the same vertex.

Thus a loop $e$ on the vertex $v$ would be written:

$e = vv$

## Also known as

Some authors refer to such an edge $e = vv$ as a self-loop at vertex $v$.