Mathematical statement that describes a connection between various objects.
A relation can be defined using three elements : a set of departure, a set of destination and a rule that associates certain elements of the domain with certain elements of the range.
A binary relation between two sets E and F is characterized by a subset of the Cartesian product E \(times\) F, that is, a collection of ordered pairs whose first component is in E and whose second component is in F.
Example
This is a sagittal diagram of the relationship “… is a divisor of…” from the set E = {2, 3, 4, 5} to the set F = {1, 2, 4, 8, 16} :
