Event · 2026-09-04
Reasoning with verification
Fermat's theorem: Lean formalization
Anthropic reported an 11-day Claude-assisted computer-checked formalization. It verifies a known result rather than newly solving Fermat's theorem.
The team used Prove2Me and an internal research model comparable to Fable 5.1. Lean checks formal inference; matching the intended theorem statement also matters. This advances mathematical autoformalization, not a general reliability guarantee for agents.
Sources
Anthropic · publication 2026-09-04Open primary source