I think Perelman himself wouldn't care too much what you call him. He would say something like: “Everybody understood that if the proof is correct then no other

I think Perelman himself wouldn't care too much what you call him. He would say something like: “Everybody understood that if the proof is correct then no other recognition is needed.” (As he said before.) You don't need a license to be a mathematician. There's this conjecture, undecided for 100 years. Whoever solves it gets the glory. He doesn't have to be a "mathematician" or an "expert". A correct proof is all it takes. He solved it, and all that's left for us is to discuss whether he's an expert or not:)