[singularity2001]

You are badly informed the counter-example was found shortly before. Terrence just tried to replicate how it was found.

[pansa2]

Has the conversation that originally led to the counterexample been released? Surely it was similar to this one, also driven by a highly knowledgeable mathematician.

No AI would have been able to find it if asked to "Find a counterexample to the Jacobian conjecture. Make no mistakes".