Cambridge and King's Find Mismatches in OpenAI Proof and Checking Code

Researchers at University of Cambridge and King's College London found at least two mismatches between OpenAI's written proof and its Lean code — Lean being software that checks math proofs — for a Navier-Stokes-related fluid problem. Reported Oct. 8, 2026, as OpenAI released hundreds of claimed solutions, with only 10 of 719 papers including chain of thought, its step-by-step reasoning.