| |
| | Initial and Terminal Objects (Site not responding. Last check: 2007-10-21) |
 | | An object q is universal, or initial, if for every object r in the category, there is one and only one morphism from q to r. |
 | | An object q is couniversal, or terminal, if for every object r in the category, there is one and only one morphism from r to q. |
 | | For instance, in the category of sets, the empty set is initial, a set with 1 element is terminal, and since these objects have different cardinalities, there is no zero object. |
| www.mathreference.com /cat,uni.html (185 words) |
|