Levent Alpöge announced on X a counterexample to the 1939 Jacobian conjecture, crediting Anthropic’s Claude Fable 5 as collaborator. Commentary stressed AI can accelerate discovery while peer review and human judgment remain essential. The episode joined a summer wave of AI-assisted pure-math claims. It matters because capability milestones reset what labs, investors and researchers treat as the near-term frontier. The piece has also been circulating in social discussion among people who watch this beat. Caveat: formal peer review and independent replication still need to catch the most dramatic claims.