Anthropic says Claude worked “largely autonomously” over 11 days to formalize the proof of Fermat's Last Theorem in the Lean programming language
We are sharing the first complete computer-checked proof of Fermat's Last Theorem. Claude worked largely autonomously over 11 days …
Anthropic
Context & Ripple Effects
Anthropic had already used Claude on open-ended mathematics: its Riemann-hypothesis attempt did not solve the problem but produced progress on a related one. It also presented Claude as a scientific-workflow tool through experiments in protein design and chemical analysis.
The move from exploratory math to a Lean artifact changes the evidentiary standard. A formal proof can be checked by a proof assistant, separating a model's generated reasoning from the verification of the resulting result.
First-order effects
Mathematicians and Lean users gain a complete machine-checkable formalization to inspect, verify, and build upon, while Anthropic gains a concrete benchmark for Claude's long-horizon technical work.
Anthropic's claim of largely autonomous work over 11 days shifts attention from isolated theorem-proving suggestions to an agent completing a large formalization workflow.
Second-order effects
Anthropic's proposed scientist access program gains a stronger case for workflows where models produce outputs that can be independently checked, rather than only prose explanations.
Competing AI labs pursuing mathematical reasoning face pressure to demonstrate verifiable artifacts and sustained task execution, not just answers to unsolved-problem prompts.
Third-order effects
If formal proof assistants become standard validators for model-generated mathematics, research AI evaluation will increasingly reward proof-carrying outputs whose correctness is machine-checkable.
The larger opportunity is a division of labor in which models generate formal research artifacts while verification systems provide the trust layer.
The trend: AI research tools are moving from generating plausible technical reasoning toward producing formally verifiable outputs for scientific and mathematical workflows.
apropos of nothing it is pretty funny in Star Trek TNG captain Picard is doing some Gentleman Science trying to prove fermat's last theorem in his free time — he claims it's been unsolved for centuries — and then it was proved one year after the show ended
Checking that a major mathematical proof is correct can take years. Formalization—converting the mathematical reasoning into a form computer proof assistants like Lean can verify—can help. Last month, Claude completed the first formalized proof of Fermat's Last Theorem, one of th…
Fermat's Last Theorem is finally sealed. Congratulations to all the contributors, especially Kevin Buzzard and his vast team of students and post-docs who did the big part of the proof in the project https://github.com/... But the story continues because the proof is not yet form…
If you had told me in undergrad I'd love to see ~fully automatic formalization I would have bet against, and if you had told me that the machine doing it would have a running color commentary on the importance, I'd have thought you under the influence. https://www.anthropic.com/.…
With the caveat that I am not a professional mathematician, this result is the most significant that I have seen for the field of mathematics thus far. The ability to automate formalization is the ability to accelerate progress, whether that is done by machines or humans or both.
Claude wrote 13 million lines of coherent Lean code to formalise Fermat's last theorem in 11 days. Large implications for formal verification as a whole.
Hey, Claude formalized Fermat's Last Theorem. — “Fermat's Last Theorem was first proven in 1995 by Sir Andrew Wiles, more than 350 years after it was conjectured. …
It will take us a while to understand the implications of this achievement. — Lots of questions. — What will research mathematicians be doing in the future? …