If a collection of closed sets of arbitrary cardinality in a metric space has empty intersection, does some countable subcollection

general-topologymetric-spaces

In this question I claim that every nested sequence of bounded closed subsets of a metric space has nonempty intersection if and only if the space has the Heine-Borel property. However, there's something that can throw a wrench in the proof: what if it is possible for there to be an uncountable collection of closed subsets with empty intersection such that every countable subcollection has nonempty intersection?

Is this possible in a metric space?

Best Answer

Let $X$ be an uncountable set endowed with the discrete metric. Then the family $\{X\setminus\{x\}\,|\,x\in X\}$ is an uncountable family of closed subsets with empty intersection. But no countable subfamily has that property.