Many years ago, when I was an undergraduate student, I had a desk (and an unlimited access to a decent library) at what is now known as the Sobolev Institute of Mathematics (my university had close connections with it), and it had so happened it was my informal duty to write answers to letters with proofs of the Fermat Last Theorem and stuff like that were steadily coming to the Institute. Inventions of various systems of "supernumbers" were a prominent thread. In Sergeyev's case, I experience déjà vu all over again.