===== Relation domain =====
==== Set ====
| @#55CCEE: context     | @#55CCEE: $ R $ |
| $ c\in R $ |
| @#55EE55: postulate   | @#55EE55: $ \forall c.\ \exists a,b.\ c=\langle a,b\rangle $ |
| @#FFBB00: definiendum | @#FFBB00: $ x\in \mathrm{dom}(R) $ |
| @#55EE55: postulate   | @#55EE55: $ \exists y.\ \langle x,y \rangle\in R $ |

==== Discussion ====
=== Reference ===
Wikipedia: [[http://en.wikipedia.org/wiki/Domain_of_a_function|Domain of a function]]
==== Parents ====
=== Context ===
[[Ordered pair]]