In addition to jasode's comment, which I endorse, I'd still argue that Charlie solved the problem. At some point in time, Bob and Charlie both had the same information (Bob's notes). From that same information, Charlie got to the final solution and Bob didn't, despite Bob having the advantage of years of familiarity with the problem. I feel like Charlie deserves quite a bit of credit. Depending on the circumstances, I might argue that Bob deserves a greater share of the credit than Charlie, but I think it would not be right to claim that Charlie didn't solve the problem (I'm intentionally leaving off any explicit qualifiers of amount of help, because my original statement was "solve an open math problem" which also has no such qualifiers).

Now of course Alice has the advantage of massive parallelization, but that's not a reason to discredit her, that's a genuine advantage that she has, applicable to all problems.

To respond to a couple specific points:

> whether Bob’s contributions were required to Alice’s final step

Even if Bob's contributions were required, I don't think that's a reason to fully discredit Alice.

> Alice is capable of solving a second open math question

Given that AI has already solved dozens of open math questions, I don't think this is up for debate.