Equivalence Relation

Equivalence relation - Wikipedia

A binary relation ~ on a set X is said to be an equivalence relation, if and only if it is reflexive, symmetric and transitive. That is, for all a, b and c in X:

• a ~ a. (Reflexivity)
• a ~ b if and only if b ~ a. (Symmetry)
• if a ~ b and b ~ c, then a ~ c. (Transitivity)