Separable space

In mathematics, a topological space is called separable if it contains a countable, dense subset; that is, there exists a sequence of elements of the space such that every nonempty open subset of the space contains at least one element of the sequence. Contrast separability with the related notion of second countability, which is in general stronger but equivalent on the class of metrizable spaces.

Separable space

In mathematics, a topological space is called separable if it contains a countable, dense subset; that is, there exists a sequence of elements of the space such that every nonempty open subset of the space contains at least one element of the sequence. Contrast separability with the related notion of second countability, which is in general stronger but equivalent on the class of metrizable spaces.