A relation is any subset of a Cartesian product. For instance, a subset of 
, called a "binary
relation from 
to 
," is a collection of ordered
pairs 
with first components from 
and second components from 
,
and, in particular, a subset of 
is called a "relation on 
." For a binary relation 
, one often writes 
to mean that 
is in 
.
Relation
See also
Adjacency Relation, Antisymmetric Relation, Argument Addition Relation, Argument Multiplication Relation, Binary Relation, Closure Relation, Cover Relation, Equivalence Relation, Irreflexive, Partial Order, Recurrence Relation, Reflection Relation, Reflexive, Symmetric Relation, Transitive, Translation RelationExplore with Wolfram|Alpha
Cite this as:
Weisstein, Eric W. "Relation." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/Relation.html