It is very unlikely to be plagiarized, and claims of plagiarism are largely unfounded and show a lack of understanding of the situation. They fall apart when reviewing the timeline, and what was actually solved.

This is the timeline:

On June 29, Buckmaster opted out of model training, and stopped allowing his chats to be used as training data with OpenAI https://mastodon.social/@tristanbuckmaster/11723341370570119...

On August 15, Buckmaster and Alpöge found their blow-up for 3D incompressible Euler with forcing https://cims.nyu.edu/~tristanb/statement.pdf

In late August, OpenAI completed a pretrain of its latest internal model. A model derived from this pretrain, built after August 28, found a solution to 3D incompressible Euler without forcing and Navier-Stokes with forcing. https://openai.com/index/navier-stokes-solution/

To explain who solved what (I copied from here: https://x.com/IlinVasily29521/status/2097554700321329393 )

  Tristan + Levent: 3D incompressible Euler with forcing
  OpenAI: 3D incompressible Euler without forcing
  OpenAI: Navier-Stokes with forcing
  No one: Navier-Stokes without forcing

Tristan+Levent ticked the weakest case, OpenAI ticked the two next weakest, then the final case is unsolved. Only the last two are eligible for the Millennium Prize. The Navier-Stokes general case remains unsolved.

Buckmaster disabled model training long before the August 15 breakthrough results, so these chats were not used as training data for OpenAI's model which solved Navier-Stokes.

Additionally, Tristan and Levent only solved the easiest version of the problem and did not have the key insights to solve the harder versions of the problem required for the Millennium Prize.

And OpenAI directly addressed these plagiarism claims, and called them impossible: https://www.nytimes.com/2026/09/10/science/tristan-buckmaste...

"We can say categorically that it is impossible for Dr. Buckmaster’s Codex prompts over the last two months to have influenced the system in any way, including training."

I’m unsure or not if this is true but I did see some people saying that that checkbox when off only anonymizes your data, but it still may be trained on. Someone correct me if I am wrong