A complete theory of everything: Satisfiability in the universal domain Harvey M. Friedman october 10, 1999 Friedman@math.ohio-state.Edu [Book Review]

Here we take the view that LPC(=) is applicable to structures whose domain is too large to be a set. This is not just a matter of class theory versus set theory, although it can be interpreted as such, and this interpretation is discussed briefly at the end.