An ongoing multi-author open source project to formalise a proof of Fermat's Last Theorem in the Lean theorem prover.

The project is currently being led by Kevin Buzzard. From October 2024 it will be funded by grant EP/Y022904/1, awarded by the EPSRC. The project is hosted at Imperial College London. Kevin would like to extend many many thanks to both of these institutions for their ongoing support of this nonstandard research.

General information ("What is Fermat's Last Theorem/Lean?" / "Why are you doing this?" etc) is here.

The route we will be taking was planned out essentially entirely by Richard Taylor in discussions with Buzzard. It is a modern variant of the original Wiles/Taylor-Wiles proof. For more details about the mathematics behind the proof, a good place to start is the blueprint.