Definition:Density of Topological Space

Definition

Let $T$ be a topological space.

The density of $T$ is the smallest cardinality of the everywhere dense subsets of $T$:

$\map d T := \min \leftset {\card A: A \subseteq T \land A}$ is everywhere dense$\rightset{}$

Sources

• 1989: Ryszard Engelking: General Topology (revised and completed ed.)

• Mizar article TOPGEN_1:def 12