Paul would be 100 today.    "A superdiagonal, ~ again." -- Paul Erdos. I'm putting words into Paul's mouth, but the diagonal argument is a very common proof method, and I've used it many times.  I'm sure Paul did an order of magnitude more proofs than I did.  Also... he gave a problem to Alex Soifer, and I solved it with a superdiagonal argument. Anyways, does anyone thing Paul might have said this at some point? Ed Pegg Jr