@TedShifrin I have created at least something very basic, since you know this area better and you are active in this tag, you might be able to improve the wording. I will also leave up to you whether you post a request on meta to create a
tag warning for this tag.
Let $(X,\mathscr T)$ be topological space with dense subset $D$ and a
closed,relatively discrete subset $C$ such that $\mathscr{P}(D)\precsim$ $C.$ Then $(X,\mathscr T)$ is
not normal.
Notations and definition in the theorem:-
$X\sim Y$- There is a bijection map from $X$ to $Y$.
$X...
