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Does X always has a finite open cover?

X is a metric space. I think it is false because there is a possibility to have closed neighborhood near a point in X.

2 Answers 2

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What is the definition of an open cover? For a topological space $X$, an open cover is a collection of open sets $\{V_i\}_{i \in I}$, such that $X = \bigcup_{i \in I} V_i$. So just take the open cover $\{X\}$.

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Every metric space has an open covering consisting of exactly one open set, namely $X$ itself.

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    {X} is a finite open cover of X.2012-11-08