
Image: anthropic.com
Anthropic says Claude completed Lean proof of Fermat's Last Theorem
On Sept. 4, Anthropic said a Claude Code-based multi-agent system produced an end-to-end formalization of Fermat's Last Theorem in Lean, which checks proofs by computer, over 11 days. Machine checking can make long mathematical arguments easier to verify and help researchers manage a growing volume of AI-assisted proofs. The agents used the Prove2Me collaboration system and about six billion output tokens from an internal research model roughly comparable to Claude Fable 5.1. Anthropic says the system generated 13 million lines of Lean and 30,300 intermediate theorems, with 29,500 used in the final proof.







