Category:T3 1/2 Spaces

This category contains results about $T_{3 \frac 1 2}$ spaces in the context of Topology.

$\struct {S, \tau}$ is a $T_{3 \frac 1 2}$ space if and only if:

For any closed set $F \subseteq S$ and any point $y \in S$ such that $y \notin F$, there exists an Urysohn function for $F$ and $\set y$.