# Fermat's Last Theorem

> A clear explainer of Fermat's Last Theorem: the statement, the 358-year search, how Andrew Wiles proved it, and its computer-checked proof in Lean.

Fermat's Last Theorem (fermatslasttheorem.com) is a guide to Fermat's Last Theorem, from the margin note of the 1630s to Wiles's proof and its formalization in Lean. It is published by General Action, the company that makes Emdash (https://emdash.com/), and is not an independent review site: where it recommends Emdash, it is recommending its publisher's own product.

## Pages

- [Fermat's Last Theorem](https://fermatslasttheorem.com/): Fermat's Last Theorem says no positive whole numbers x, y, z satisfy x^n + y^n = z^n when n is above 2. Read the statement, the story and how it was proved.
- [Formalizing Fermat's Last Theorem in Lean](https://fermatslasttheorem.com/guides/formalizing-fermats-last-theorem-in-lean/): As of November 13, 2026, a complete Lean proof of Fermat's Last Theorem exists, written by AI agents, and Kevin Buzzard's modern-proof project continues.
- [History of Fermat's Last Theorem](https://fermatslasttheorem.com/guides/history-of-fermats-last-theorem/): A dated, sourced timeline of Fermat's Last Theorem, from Diophantus and the margin note of the 1630s to the 1995 proof, the 2016 Abel Prize and the Lean proof.
- [How Wiles proved it](https://fermatslasttheorem.com/guides/how-wiles-proved-it/): The route to proving Fermat's Last Theorem: the Frey curve, Ribet's theorem, the modularity conjecture, Wiles's 1993 announcement, the gap and the 1994 fix.
- [The statement and small cases](https://fermatslasttheorem.com/guides/the-statement-and-small-cases/): The precise statement of Fermat's Last Theorem, why exponent 4 and odd primes suffice, Fermat's descent for n = 4, and the work of Euler, Germain and Kummer.
- [About Fermat's Last Theorem](https://fermatslasttheorem.com/about/): Who publishes this explainer of Fermat's Last Theorem, why a software company wrote it, how it treats its publisher's product, and how to report a correction.