Definition:Loop


 * Graph Theory:
 * Loop: an edge $e$ of $G$ whose endvertices are the same vertex.


 * Abstract Algebra:
 * Algebra Loop: a quasigroup with an identity element.


 * Set Theory:
 * Relational Loop: a subset of a relation of the form $\set {\tuple {a_1, a_2}, \tuple {a_2, a_3}, \ldots, \tuple {a_{n - 1}, a_n}, \tuple {a_n, a_1} }$


 * Topology:
 * Loop: a path whose endpoints coincide


 * Matroid Theory:
 * Loop: An element $x$ of a matroid such that $\set x$ is a dependent subset

Also see

 * Definition:Cycle
 * Definition:Path