Claude Formalizes Fermat's Last Theorem in 11 Days

Anthropic used Claude to create a computer-verifiable version of the proof of Fermat's Last Theorem, a 129-page mathematical proof originally developed by Andrew Wiles in 1995. The formalized proof comprises 13 million lines of Lean code, making it the largest file of its kind, and was completed in just 11 days — far faster than the several years mathematicians had anticipated. The AI model operated with minimal human input, deploying dozens of agents that generated 6 billion tokens of output and proved 29,500 intermediate theorems. A key breakthrough came when Claude was given access to an open-source tool called Prove2Me, which helped agents determine optimal next steps and reduce inference costs.