An AI Formalized and Verified Fermat's Last Theorem in 11 Days, a Task Expected to Take Years

An AI system from Anthropic has formally verified Fermat’s Last Theorem end-to-end in 11 days, a task that historically took humans years. Andrew Wiles spent seven years working on the problem, announcing a proof in 1993; a flaw was later corrected with collaborator Richard Taylor over an additional year. Anthropic says dozens of Claude agents converted the accepted human argument into 13 million lines of Lean, a language that checks logic step by step. The system proved over 30,000 intermediate theorems and used 29,500 of them in the final construction. Claude did not discover the theorem independently; it translated and verified a known proof. Nature quotes number theorist Alex Kontorovich calling the result “mind-blowing.”