What happened
OpenAI reports that after rumors on 1 September 2026 that other researchers had resolved Millennium problems, it launched a multi-agent evaluation of an internal model still in training and more capable than GPT-6 Astra. About 10,000 concurrent agents ran on Navier–Stokes; OpenAI says they reached a resolution on 5 September after roughly 88 hours, then Astra spent about 17 hours on Lean formalization (complete 6 September). The claimed theorem is finite-time blowup for an initially smooth fluid at rest, with a smooth force and bounded energy. That matches Fefferman’s official statements C and D. Clay gives solvers four ways to resolve the problem and explicitly grants “reasonable leeway”; C and D are not a later loophole. OpenAI has not resolved the famous unforced A/B question, which remains open. A valid C or D proof is still a resolution of the Clay problem on Clay’s own terms. OpenAI says it will not claim the prize. The Clay Mathematics Institute wrote on 11 September that the Navier–Stokes problem has “apparently been settled,” while stressing that formal evaluation and credit will take time. Nature quoted Navier–Stokes specialist Luis Martínez Zoroa calling the result “truly remarkable.” That is not peer review, but it is more than a lab press release. Tristan Buckmaster alleges OpenAI moved after learning of his work with Levent Alpöge. The live dispute is over priority, timing, and whether unpublished interactions could have influenced the process—not, at present, a strong claim that the theorem is false. OpenAI says the proofs differ (forced Navier–Stokes versus their forced Euler/IPM/Boussinesq program), that it did not see their manuscripts, and that an investigation found Buckmaster’s Codex prompts could not have influenced the search model. Hodge, Birch–Swinnerton-Dyer, Riemann, Yang–Mills, and P vs NP are not recorded as solved. Update (2026-09-08): On the Navier–Stokes Millennium Prize Problem. We’re sharing an AI-generated solution to the Navier–Stokes Millennium Prize Problem, including a writeup and a formal proof in Lean. Update (2026-09-18): AI cracked the Navier–Stokes challenge. What does that mean for physics?. AI cracked the Navier–Stokes challenge. What does that mean for physics? Update (2026-09-08): On the Navier–Stokes Millennium Prize Problem - OpenAI. On the Navier–Stokes Millennium Prize Problem OpenAI