10975564: Just for the case that we indeed remove the reflexive tag.

A relation $\square$ is reflexive if $A \square B \iff B \square A$. For example, the relation "equals to" on integers is reflexive, but the relation "less than" is not.

At the moment, there are 4 questions having this tag:

355187

340715

271923

271638

I have removed reflexive tag from all question where it was used.

If someone consider the tag useful, it should be easy to restore the current status from the information I copied above.

I've added tag-excerpt and tag-wiki to [tag:separation axioms].

Tag-excerpt: Separation axioms are properties of topological space which, roughly speaking, say in what way can be two points, a point and a closed set or two points be "separated".

Tag-wiki:

Separation axioms are properties of topological space which, roughly speaking, say in what way can be two points, a point and a closed set or two points be "separated".

The most important separation axioms are $T_0$-spaces, $T_1$-spaces, Hausdorff, regular, completely regular (also known as Tychonoff) and normal spaces.

I'll be very glad if someone improves the tag-excerpt and the tag-wiki.

A natural question is whether we want separation-axioms tag.

I am not entirely sure, but perhaps it might be useful. The tags connectedness and compactness are, to some extent, similar.