<P> In graph theory , a loop ( also called a self - loop or a `` buckle '' ) is an edge that connects a vertex to itself . A simple graph contains no loops . </P>
<P> In graph theory , a loop ( also called a self - loop or a `` buckle '' ) is an edge that connects a vertex to itself . A simple graph contains no loops . </P>
an edge of a graph that joins a vertex to itself is called a
an edge of a graph that joins a vertex to itself is called a
a loop
a loop