Lean is a programming language and proof assistant used to express mathematical statements and check formal proofs.
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's Aristotle paper combines informal reasoning with Lean proof search and a geometry solver, reporting gold-medal-equivalent performance on 2025 IMO problems. The practical possibility is generated work that can be checked against an explicit mathematical statement.
Understand what machine-checked proofs establish, which assumptions they use and what people still need to decide.
A valid formal proof does not independently establish that the chosen specification represents a user's intended problem or a complete real-world safety requirement.
Public documentation, source code and mathematical libraries