\begin{definition}[Definition:Closure (Topology)/Definition 2]
Let $T = \struct {S, \tau}$ be a topological space.
Let $H \subseteq S$.
The '''closure of $H$ (in $T$)''' is defined as:
:$\ds H^- := \bigcap \leftset {K \supseteq H: K}$ is closed in $\rightset T$
That is, $H^-$ is the intersection of all closed sets in $T$ which contain $H$.
\end{definition}