OpenAI appears to have made a subtle error when publishing its proofs of the Navier-Stokes problem, a team of mathematicians has claimed. The error doesn’t mean that the proofs are incorrect or that OpenAI hasn’t correctly solved the problem, but it does call into question whether mathematical results generated by AI models can always be relied on.

“What has to be done with all of these large language model-generated proofs is that they will have to be read by humans, and this creates an enormous extra burden on mathematicians,” says Anders Hansen at the University of Cambridge.

On 8 September, OpenAI announced that it had found a solution to the Navier-Stokes problem, one of the most famous open problems in mathematics. It published the proof in two versions – one written in “natural language”, meaning a combination of English and mathematical symbols, as a human mathematician would write, and another written in the computer code Lean. The Lean proof is meant to be a formalisation of the natural-language version, allowing a computer to mechanically verify that all of its logical statements are true. The problem is, say Hansen and his team, that they don’t match.