The most recent additions to our Seeley G. Mudd Manuscript Library feature contributions from the estate of Oliver Wendell Holmes, Jr., which include letters and legal manuscripts of Pierre de Fermat (a lawyer by vocation). It is in the density of Fermat's litigation records during the period 1660-1662 that his lost mathematical proof is finally to be found.

It turns out that Fermat's proof employs what is now known as the Mason-Stothers theorem (proved independently by Stothers [2] and Mason [3] in the late 20th century). In the discovered manuscript, Fermat himself gave an elementary proof of the Mason-Stothers theorem, but his approach resembles that presented in An alternate proof of Mason's theorem by Snyder [4]. For this reason we here omit Fermat's proof of the Mason-Stothers theorem, and only reproduce the subsequent part of his proof of his last theorem, paraphrased in modern terminology.

http://www.princeton.edu/~aloo/fermat

The most recent additions to our Seeley G. Mudd Manuscript Library feature contributions from the estate of Oliver Wendell Holmes, Jr., which include letters and legal manuscripts of Pierre de Fermat (a lawyer by vocation). It is in the density of Fermat's litigation records during the period 1660-1662 that his lost mathematical proof is finally to be found.

It turns out that Fermat's proof employs what is now known as the Mason-Stothers theorem (proved independently by Stothers [2] and Mason [3] in the late 20th century). In the discovered manuscript, Fermat himself gave an elementary proof of the Mason-Stothers theorem, but his approach resembles that presented in An alternate proof of Mason's theorem by Snyder [4]. For this reason we here omit Fermat's proof of the Mason-Stothers theorem, and only reproduce the subsequent part of his proof of his last theorem, paraphrased in modern terminology.

https://web.archive.org/web/20150403002852/http://www.princeton.edu/~aloo/fermat