Andrew Wiles was a 20th century Earth mathematician. In 1993, after several years of study, he announced his proof of Fermat's last theorem. Though the proof initially contained some flaws, by 1995 they were corrected and the proof verified.
Though technically correct, Wiles' proof was extremely complex and used methods unknown during Fermat's time and is therefore not considered to be the "remarkable proof" of which he had written. Subsequently, several individuals would search for alternative proofs. Eventually, this search would include individuals from other worlds, including Trill engineer Tobin Dax. Jadzia Dax would later remark that Tobin's approach to the proof was the most original since Wiles.
Fermat's actual proof would still remain unconfirmed as late as the 24th century. (TNG: "The Royale"; DS9: "Facets")