![[MONOiD]](monoid.png)
IsEquivalence( rel )
IsEquivalence returns true if the binary relation rel is an
equivalence relation and false otherwise.
gap> IsEquivalence( Relation( [ [ ], [ 1 ], [ 1, 2 ] ] ) );
false
gap> IsEquivalence( Relation( [ [ 1 ], [ 2, 3 ], [ 2, 3 ] ] ) );
true
A relation rel is an equivalence relation if rel is reflexive,
symmetric, and transitive, i.e., if rel is a symmetric preorder (see
IsPreOrder). (See also EquivalenceClasses.)
Version 2.4 (May 1998)