Category:T1 Spaces

This category contains results about $T_1$ (Fréchet) spaces in the context of Topology.
$\struct {S, \tau}$ is a Fréchet space or $T_1$ space if and only if:
$\forall x, y \in S$ such that $x \ne y$, both:
$\exists U \in \tau: x \in U, y \notin U$
$\exists V \in \tau: y \in V, x \notin V$