===== Set cardinality =====
==== Set ====
| @#55CCEE: context     | @#55CCEE: $X$ ... set |
| @#FFBB00: definiendum | @#FFBB00: $ \left|X\right|\equiv\mathrm{inf}\{\alpha\ |\ \alpha\in\mathrm{Ord}\ \land\ \alpha\approx X\} $ |

==== Discussion ====
=== Reference ===
Wikipedia: [[http://en.wikipedia.org/wiki/Cardinal_numbers|Cardinal numbers]], [[http://en.wikipedia.org/wiki/Cardinal_assignment|Cardinal assignment]], [[http://en.wikipedia.org/wiki/Von_Neumann_cardinal_assignment|Von Neumann cardinal assignment]]
==== Parents ====
=== Context ===
[[Non-strict partial order]], 
[[Bijective function]]
=== Element of ===
[[Ordinal number]]