Anthropic announced that its internal models used the prove2.me platform to formalize the complete proof of Fermat's Last Theorem using Lean.
With this achievement, the final theorem on the "100 problems to be formalized" list presented by Freek Wiedijk has been completed, marking the end of a 20-year benchmark.
The formalized proof is based on the 1995 description by Darmon-Diamond-Taylor. While the mathematical arguments themselves faithfully follow existing literature, this represents a significant advancement demonstrating the potential for automated formalization.
The codebase is massive, exceeding 13.4 million lines. It is reported that in a 96-core environment, it requires approximately 20 times the compilation time of the Lean mathematical library.
Source: Fermat's Last Theorem: Anthropic has beaten me to it (Hacker News Frontpage, 2026-09-05)