Kevin Buzzard verifies Anthropic's 13.4M-line Lean proof of Fermat's Last Theorem

AlexKontorovich · x · 2026-09-05

Mathematician Alex Kontorovich shared Kevin Buzzard's blog post independently verifying Anthropic's Lean formalization of Fermat's Last Theorem.

• Buzzard compiled the codebase and ran comparator — it checks out
• The proof spans over 13.4 million lines and takes 20x longer to compile than mathlib on a 96-core machine; even a 500GB RAM machine stutters browsing the repo
• It completes the final item on Wiedijk's list of 100 formalization challenges, following the Darmon–Diamond–Taylor (1995) route

Same event as Anthropic's official announcement, with Buzzard's verification adding mathematical-community credibility.

Original post →

More from Research

• Extreme reward functions push LLMs away from their current behavior — jessi_cata · 2026-09-05
• VeriPhy: agentic physical reasoning framework for world model evaluation — Wenzhuo Xu · 2026-09-05
• TRACES agent benchmark grades live execution loops, not answers — SucceededMind · 2026-09-05
• Pedro Domingos quips: 'new idea' called RNNs will power next-gen LLMs — pmddomingos · 2026-09-05
• LoRA Creator Edward Hu Publishes Guide on Post-Training Open-Source Models with RL — iamrobotbear · 2026-09-05
• Amid CoT monitoring buzz, one video offers a glimpse into how LLMs actually think — kastnerkyle · 2026-09-05

Research channel →