Existence of Minimal Hausdorff Space which is not Compact

From ProofWiki
Jump to navigation Jump to search

Theorem

Let $S$ be a set.

Let $\tau$ be the minimal subset of the power set $\powerset S$ such that $\struct {S, \tau}$ is a Hausdorff space.

Then it is not necessarily the case that $\struct {S, \tau}$ is compact.


Proof

Let $T = \struct {S, \tau}$ be the canonical minimal Hausdorff non-compact space.

This space has been so named on $\mathsf{Pr} \infty \mathsf{fWiki}$ in order to allow reference to it without needing to describe it whenever it is mentioned.

By Canonical Minimal Hausdorff Non-Compact Space is Minimal Hausdorff, $\tau$ is the minimal subset of the power set $\powerset S$ such that $T$ is a Hausdorff space.

By Canonical Minimal Hausdorff Non-Compact Space is not Compact, $T$ is not a compact topological space.

Hence the result.

$\blacksquare$


Sources