Relation

https://en.wikipedia.org/wiki/Relation

The term relation most often refers to a binary relation, although ternary or, generally, n-ary relations are also encountered.

A finitary relation or n-ary relation is a set of n-tuples.

Specific types of relations include:

• Binary relation (or correspondence, dyadic relation, or 2-place relation)

• Equivalence relation (reflexive + symmetic + transitive relation)

• Heterogeneous relation, a relation between possibly distinct sets

• Reflexive relation

• Serial relation

• Ternary relation (or triadic, 3-adic, 3-ary, 3-dimensional, or 3-place relation)

Relation may also refer to:

• Directed relation

• Relation algebra, an algebraic structure inspired by algebraic logic