> Not necessarily applied to OpenAI's solution to Navier-Stokes, but what happens if and when an AI genuinely appears to solve an extremely difficult problem but humans cannot independently verify the solution because understanding the proof/argument requires intelligence the verifiers biologically don't have or the resources to afford to use automated tools?

That's what Lean is for. The OpenAI LLM agents first provided a proof in natural language. Since it may be hard for mathematicians to understand and check this proof, the agents then produced a formalization in Lean. Lean is an automated proof checker. It checks whether a formal proof is correct without the need for humans to understand the proof itself.

The only way the Lean proof could still be wrong is if the conjecture was formalized wrong via misleading definitions (if it doesn't say what it seems to say) or if there is some bug in Lean itself.

Sadly, as ideal as this seems, Lean has a history of kernel bugs that allow one to prove False.

It's unlikely to be the case here as instead of hillclimbing a Lean proof for validity it appears the proof was first constructed in English before being translated to Lean, which intuitively (hopefully) reduces the chance it exploits a bug.

Surely some understanding of the lean proof is required, to make sure it proves what it claims to prove. Otherwise, what happens if the LLM includes an underhanded addition to the lean code which leads it to output a false positive?