Claude Formalizes Fermat's Last Theorem in Lean

Zephyr posted that a proof of Fermat's Last Theorem was completed in Lean with over 13 million lines of code and more than 29,000 supporting theorems. Nat McAleese stated that Claude produced the formalization in 11 days. Multiple accounts including Lisan al Gaib and Rohan Paul repeated the claim that the model handled the full formalization task. Albert Jiang and others discussed implications for reducing manual work in turning mathematical arguments into machine-checkable steps. The posts reference an AnthropicAI update on the effort.