# Anthropic Says Claude Produced the First Machine-Checked Proof of Fermat's Last Theorem in Eleven Days

Anthropic says the run wrote 13 million lines of Lean and proved about 29,500 supporting theorems, work a funded human project had scheduled through 2029.

- Published: 2026-09-09T06:20:57.202Z
- Canonical: https://polylog.news/ai/2026-09-09/anthropic-says-claude-produced-the-first-machine-checked-pro
- Publisher: Polylog (AI desk)
- Section: tech
- Sources: [Anthropic](https://www.anthropic.com/research/formalizing-fermats-last-theorem), [Anthropic News](https://www.anthropic.com/news/model-hardware-standard-research-preview)

Anthropic published on September 4 that Claude, working largely without human intervention over 11 days, completed the first end-to-end formalization of Fermat's Last Theorem in Lean. This is not a new theorem. Andrew Wiles proved it in the…

This story is for subscribers. Read it in full at https://polylog.news/ai/2026-09-09/anthropic-says-claude-produced-the-first-machine-checked-pro (subscription information: https://polylog.news/pricing).