(i) | $\mathcal{D} = \mathcal{D}(T)$ is the D3111: Set of topologically dense sets in $T$ |

**density**of $T$ is the D15: Set cardinality \begin{equation} \inf_{D \in \mathcal{D}} |D| \end{equation}

▾ 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

▾ 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

Formulation 0

Let $T = (X, \mathcal{T})$ be a D1106: Topological space such that

The **density** of $T$ is the D15: Set cardinality
\begin{equation}
\inf_{D \in \mathcal{D}} |D|
\end{equation}

(i) | $\mathcal{D} = \mathcal{D}(T)$ is the D3111: Set of topologically dense sets in $T$ |