don't understand why you'd continue arguing definitions about speed of Solomonoff induction or it being "the original problem". It's clear what we both mean.

A better question would be why you brought up the issue. We both knew what the other meant before that, but you kept bringing it up.

I believe you are wrong ... there remain possibilities for a good technical definition that preserves "generality" in an approximate implementation.

Okay, well, I'll believe it when I see it. In the mean time, I suspect it will be far more productive to exploit whatever regularity we already know about the environment, and work on building that into the inference program's prior. (Arguably, even the Occamian prior does that by using our hard-won belief in the universe's preference for simplicity!)