I was thinking of a proof of impossibility for a long-running unanswered question on this site. By a proof of impossibility, what I mean is a proof that no possible answer can solve the challenge. When I polled chat for other interested fellows, one response was this:
unfortunately, I don't think that would fit as an answer, since the question asks about solutions to the challenge, but about a proof that it's impossible
So I came here to ask: if I could prove that a challenge had no valid solutions, could I post it as an answer?