On the discussion about pi PA mei: ignore x3s and consider the predicate:
se te pi mu mei
This is "x1 is a set whose 1/2 members are x2". This makes no sense; you can't have a set with cardinality 1/2. I think part of the problem here is that we've never resolved the issue of masses (here these are not technically masses, but we are considering one object and removing some of its components, leaving behind something that resembles the original object in some clear sense) with respect to set theory. (At least as far as I know, maybe this was handled at some point.) The ad hoc solution would be to remove the relation to sets from mei altogether; set {lo se mei} to be zi'o in all cases and leave it at that. The better solution would be to figure out, in a formal sense, what exactly about "a can of oranges" causes it to make sense to say "half of a can of oranges", and more importantly what makes "a half a person" make only figurative (or, I suppose, cannibalistic, if you're into that sort of thing) sense.
This really has rather little to do with {lo no}, though.
mu'o mi'e .latros.