===== Groupoid =====
==== Collection ====
| @#FFBB00: definiendum | @#FFBB00: ${\bf C}$ in it |
| @#AAFFAA: inclusion   | @#AAFFAA: ${\bf C}$ ... category |
| @#FFFDDD: forall      | @#FFFDDD: $A,B\in{\bf C}$ |
| @#FFFDDD: forall      | @#FFFDDD: $f:{\bf C}[B,A]$ |
| @#55EE55: postulate   | @#55EE55: $f$ ... isomorphism |

==== Discussion ====
=== Reference ===
Wikipedia: [[http://en.wikipedia.org/wiki/Groupoid|Groupoid]]
==== Parents ====
=== Requirements ===
[[Isomorphism]]