[spoilers] The first time I read Permutation City I really enjoyed the reveal that Paul was originally a simulation (many times over) that only existed in the "real" world because the entire universe spontaneously came into being in order to maintain a simpler reality than the alternative in which his simulation suddenly stopped existing. Almost as if complexity itself has some kind of inertia. If that was obvious to you the first time around, kudos!
I also really enjoyed the commentary on solipsism in the context of transhumanism via the 'Peer' character.
Although part 2 doesn't explicitly explain why the universe of PC has the "complexity momentum" property, it does suggest the universe with the lowest Kolmogorov complexity is preferred (via some undescribed physical law). That is why the "ant's" universe wins; it's relative complexity is simpler than the world which Paul had created. I agree that it could have been fleshed out more fully.
I also really enjoyed the commentary on solipsism in the context of transhumanism via the 'Peer' character.
Although part 2 doesn't explicitly explain why the universe of PC has the "complexity momentum" property, it does suggest the universe with the lowest Kolmogorov complexity is preferred (via some undescribed physical law). That is why the "ant's" universe wins; it's relative complexity is simpler than the world which Paul had created. I agree that it could have been fleshed out more fully.