New answers tagged

1 vote

An axiomatic approach to the multiverse of sets

This might not precisely answer your question, but why not use topos theory? The category of (Grothendieck) topoi has as its objects generalized universes of sets whose internal logic does no not ...
user avatar
0 votes

Smallest ordinal modelling $\aleph_1$?

About well-definedness of $X_1$, "being a model of ZFC" is definable since ZFC is a recursive theory, so we could construct some $\Sigma_1^0$ predicate $\textrm{isZFCAxiom}(e)$ for $e$ a ...
user avatar
  • 293

Top 50 recent answers are included