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Normal space
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== Examples of normal spaces == Most spaces encountered in [[mathematical analysis]] are normal Hausdorff spaces, or at least normal regular spaces: * All [[metric spaces]] (and hence all [[metrizable space]]s) are perfectly normal Hausdorff; * All [[pseudometric space]]s (and hence all [[pseudometrisable space]]s) are perfectly normal regular, although not in general Hausdorff; * All [[compact space|compact]] Hausdorff spaces are normal; * In particular, the [[Stone–Čech compactification]] of a [[Tychonoff space]] is normal Hausdorff; * Generalizing the above examples, all [[paracompact]] Hausdorff spaces are normal, and all paracompact regular spaces are normal; * All paracompact [[topological manifold]]s are perfectly normal Hausdorff. However, there exist non-paracompact manifolds that are not even normal. * All [[order topology|order topologies]] on [[totally ordered set]]s are hereditarily normal and Hausdorff. * Every regular [[second-countable space]] is completely normal, and every regular [[Lindelöf space]] is normal. Also, all [[fully normal space]]s are normal (even if not regular). [[Sierpiński space]] is an example of a normal space that is not regular.
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