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Jun 27, 2016 at 10:16 history edited François G. Dorais CC BY-SA 3.0
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S Jun 27, 2016 at 6:41 history suggested yada CC BY-SA 3.0
A paracompact space $X$ is the disjoint union (or "free union") of $\sigma$-compact spaces. Such a union need not be countable, e.g. an uncountable discrete space is metrizable but not a countable union of $\sigma$-compact subspaces.
Jun 27, 2016 at 6:41 review Suggested edits
S Jun 27, 2016 at 6:41
Dec 6, 2013 at 21:23 comment added Hugo Rafael Oliveira Ribeiro I think that I was a little confused about the assumption that $X$ is $\sigma$-compact. Expressing $X$ as a disjoint union $X = \bigcup_{\alpha \in A} X_{\alpha}$, where $X_{\alpha}$ is clopen and separable, the new metric $d'$ defined by $d'(x,y) = d(x,y)$ if $x,y$ are in the same component and $d'(x,y) = 1$ if $x,y$ are in the differents components is equivalent to $d$ and $(X,d')$ is complete.
Dec 6, 2013 at 19:49 comment added Joseph Van Name A locally compact metric space is as a topological space a disjoint union of separable spaces, but a locally compact metric space is not necessarily separable since an uncountable discrete space is always locally compact, but not separable.
Dec 6, 2013 at 19:29 history edited Joseph Van Name CC BY-SA 3.0
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Dec 6, 2013 at 16:58 vote accept Hugo Rafael Oliveira Ribeiro
Dec 6, 2013 at 16:58 comment added Hugo Rafael Oliveira Ribeiro So, we can conclude that a locally compact metric space is separable... very cool. Thanks
Dec 6, 2013 at 16:05 history edited Joseph Van Name CC BY-SA 3.0
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Dec 6, 2013 at 14:44 history answered Joseph Van Name CC BY-SA 3.0