doesn't seem to be in in the literature
I ran a version of Proposition 13 in that paper through Claude just to clean up the draft of that bit before I sent it to her
The literature on this problem is small, and I'm very familiar with it.
You're missing the point here entirely, and ironically you are actually providing counter-evidence.
It appears that ChatGPT, etc, are taking information provided to them by people like you in the form of conversing with the agent and providing files, and using that information to generate output for others. This was shown where a mathematical solution ChatGPT came up with was pretty much exactly like an unpublished solution that had been discussed with ChatGPT by a couple researchers
Do you really think you are the only person in the world discussing that particular thing with the AI agent? You say you're very familiar with the literature in that field. Has your brain literally been built upon every word of that information that has ever been published, like an LLM? Of course not. So it doesn't matter how familiar you think you are with the literature, an LLM's "database" of that literature is beyond anything you could achieve.
Your example does not prove the LLM didn't connect existing dots, or produce that solution from existing information, either published or unpublished that was provided to it in chat sessions like yours.