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Working notes from the studio. The tools I build, the workflows I keep, the mistakes I paid for.

67 entries · latest 2026-09-06

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RAXXO Studios 10 min read

Claude Just Formalized Fermat's Last Theorem in Lean

Anthropic says an internal Claude research model formalized Fermat's Last Theorem in Lean over 11 days. Here is what the numbers actually mean.

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  • Anthropic says an internal research model built on Claude worked largely autonomously for 11 days to produce the first complete, computer-checked formalization of Fermat's Last Theorem in the Lean proof language
  • The run wrote roughly 13 million lines of Lean code and proved 30300 intermediate theorems, about 29500 of them used in the final proof, while consuming close to 6 billion output tokens
  • This is a formalization of Andrew Wiles' existing 1995 proof, not a new mathematical discovery, and it ran on an internal research model tuned for this project, not the Fable or Mythos models available today

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