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answer: direct
beat: ai-technology
source: 1 article · updated: August 6, 2026
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What is a Lean proof and why does it matter for AI math?

Lean is a proof assistant whose compiler kernel mechanically checks every logical step. If a proof compiles with zero sorry placeholders, every step is verified — no trust required. OpenAI released Lean 4 proof certificates for all ten results, meaning anyone can independently verify the solutions by running the compiler.

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OpenAI's Astra Model Solved 10 Open Math Problems — With Machine-Verified Proofs

OpenAI's Astra solved 10 longstanding open math problems with fully verified Lean 4 proofs and zero unproven steps. Total compute cost: roughly $2,000.

Crashtech Editorial August 6, 2026 How AI Actually Works

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