Relations
Relations are ordered pairs between sets.
Contents
Description
A relation takes members of two sets, A and B, and constructs ordered pairs.
A relation R between A and B is a subset of their Cartesian product. R ⊆ A × B.
A particular ordered pair (a,b) satisfying a relation R may be written as aRb.
The concept of equivalence is formalized as a relation R satisfying:
reflexivity: aRa
symmetry: aRb -> bRa
transitivity: aRb and bRc -> aRc
a, b, and c are in an equivalence class.