I thought that tag synonyms were meant simply to be proposed and left to survive or die on their own, but I see another question in HNQ about tag synonyms, so maybe one is supposed to raise a corresponding Meta question. I think that positive-characteristic and characteristic-p are synonyms.
EDIT: As @MartinSleziak points out, I perhaps stated this a bit vaguely. Concretely, I already proposed the synonym, and it awaits the necessary votes.
[tag:positive-characteristic]in the title, as in the linked question, but it wouldn't let me. $\endgroup$
positive-characteristiccurrently has 83) as the synonym of the one with more (
characteristic-pcurrently has 253). $\endgroup$