Since 'X' is separable, let be a countable dense subset.
Let be a countable collection of open dense subsets.
It should be noticed that this terminology is different from the notion of a dense subset in general topology.
It also has a countable dense subset, namely the set of rational numbers.
In a topological space, every constructible set contains a dense open subset of its closure.
In g they form an open and dense subset.
To make this more formal, one has to explain that T is bounded only on a dense subset and can be completed.
A space is separable if it has a countable dense subset.
In mathematical analysis, the rational numbers form a dense subset of the real numbers.
In this way, arbitrarily dense subsets of the group can be found.