Existence as a real predicate

[robvalue]

You seem to be talking about abstract concepts that don't map to reality. I don't think it's reasonable to say that they map to a non-existent entity. That's an attempt to conflate the real and the abstract.

If you really wanted to go down that road, I think you'd have to say "nonexistence" is a single entity in reality (although this is still nonsense, really) and that all abstract concepts that don't exist in reality map to this one entity. That's about as close as you can get, and it's still dishonest conflation.