===== Non-negative rational number =====
==== Set ====
| @#FFBB00: definiendum | @#FFBB00: $ r \in\mathbb Q_+ $ |

| @#55CCEE: context     | @#55CCEE: $ r \in \mathbb Q $ |

| @#55EE55: postulate   | @#55EE55: $ r \ge 0 $ |

==== Discussion ====
=== Reference ===
Wikipedia: [[http://en.wikipedia.org/wiki/Rational_number|Rational number]]
==== Parents ====
=== Refinement of ===
[[Non-negative real number]]
=== Subset of ===
[[Rational number]]