| |
| | Hausdorff space - Wikipedia, the free encyclopedia (Site not responding. Last check: 2007-10-19) |
 | | space, or separated space, iff, given any distinct points x and y, there are a neighbourhood U of x and a neighbourhood V of y that are disjoint. |
 | | In contrast, non-preregular spaces are encountered much more frequently in abstract algebra and algebraic geometry, in particular as the Zariski topology on an algebraic variety or the spectrum of a ring. |
 | | Compact preregular spaces are normal, meaning that they satisfy Urysohn's lemma and the Tietze extension theorem and have partitions of unity subordinate to locally finite open covers. |
| xahlee.org /_p/wiki/Hausdorff_space.html (828 words) |
|