The function BB() is necessarily larger than any function you can compute. It's a surprising/fascinating result.

I've had a lot of success answering questions like this by asking an LLM. It turns out they understand each other and do a great job explaining.

Here's a link for this paper:

https://claude.ai/share/81b1380d-ca03-4ecb-8475-8e0bb95ea87e

Thanks, I enjoyed that explanation quite a bit (didn't understand everything, but enough to get a major clue).