This is a bigger result, of the form “asked ChatGPT, got a wrong answer, but thinking about it led to a right answer.” And the conjecture was much-discussed but not widely believed.
Alex Perry has disproved the period-index conjecture in dimension 3. His period-2, index-8 example is the precise case Ben Williams and I expected but could not prove. Blog: antieau.github.io/2026/08/05/p... Paper: arxiv.org/abs/2608.03684