Contributed by
Vijay Fafat
This is a neat little story which plays on the fancy that one has found a very simple proof for Fermat's last theorem...if only one can write it down before the epiphany passes. A young mathematician (who has been asked to stay away from cryptography research after getting into trouble with the NSA) starts toying with the idea of obtaining a simple solution to FLT. The idea gets implanted in his brain by a trio of timetravelling students whose time machine creates "wakes of dejavu". What happens after that is mildly funny, including some rhapsodization about how FLT might be solved graphically and a quick love interest. One of my favorite lines in the story: "Every mathematician lived in dread of the NSA."

Note that Fermat's Last Theorem (the statement that there are no positive, whole number solutions to the equation x^{n}+y^{n}=z^{n} when n>2) is famous for being a mathematical statement that is very simple to make but notoriously difficult to prove or disprove. In fact, it was an open problem for hundreds of years until Andrew Wiles finally completed a proof in 1994. It is a common popular belief that there must be some elementary proofs of the theorem out there (either waiting to be discovered or known in secret as the story suggests). However, Wiles' proof is quite complicated (depending on advanced mathematical knowledge of elliptic curves and modular functions which are not available to a casual puzzle solver) and it seems likely that the statement cannot be proved in a much more elementary way at all.
Originally published in Analog MidDecember 1994 and reprinted in the author's anthology "Twenty Questions".
