On 9 and 10 November 2026, a committee appointed by OpenAI and chaired by physicist David Gross said an AI-generated proof of the “existence” half of the Yang-Mills Millennium Prize Problem had been formally verified in the Lean proof language, while stating that it does not yet fully understand the proof and that the harder “mass gap” half is untouched.
The result is the most closely watched test so far of how research communities should vet AI-produced mathematics, and it is contested on process as well as substance.
What happened and when OpenAI announced on the evening of Monday 26 October 2026 that an internal model had produced a proof of the existence part of the Yang-Mills problem, one of the Clay Mathematics Institute’s seven Millennium Prize Problems (a $1 million prize).
According to Scientific American ‘s 27 October report, OpenAI said the model reached the result on 9 September but kept it private until the argument had been encoded in Lean, and that the company did not release the proof but handed it to a group of experts to bring it into the mathematical literature.
That group, described by Scientific American as a committee of “shepherds”, is led by David Gross and includes four colleagues he chose; Michael R. Douglas of Harvard is a named member. On 9 November the committee issued a statement saying the result proves the existence of pure Yang-Mills theory under the standard problem statements. On the night of 10 November it posted a document on GitHub…