▾ Set of symbols
▾ Alphabet
▾ Deduction system
▾ Theory
▾ Zermelo-Fraenkel set theory
▾ Set
▾ Subset
▾ Power set
▾ Hyperpower set sequence
▾ Hyperpower set
▾ Hypersubset
▾ Subset algebra
▾ Subset structure
▾ Topological space
▾ Closure point
▾ Set closure
▾ Topologically dense set
▾ Set of topologically dense sets
Topological space density
Formulation 0
Let $T = (X, \mathcal{T})$ be a D1106: Topological space such that
(i) $\mathcal{D} = \mathcal{D}(T)$ is the D3111: Set of topologically dense sets in $T$
The density of $T$ is the D15: Set cardinality \begin{equation} \inf_{D \in \mathcal{D}} |D| \end{equation}