Monotone inductive definitions and consistency of New Foundations [chapter]

Sergei Tupailo, Costas Dimitracopoulos, Ludomir Newelski, Dag Normann, John R. Steel
Logic Colloquium 2005  
In this paper we reduce the consistency problem for NF to consistency of a certain extension of Jensen's NFU. Working in NFU+Pairing, which is known to be consistent relative to Zermelo set theory, due to Jensen [19], we define a certain monotone operation pw and conclude that existence of its least fixpoint is sufficient to model NF.
doi:10.1017/cbo9780511546464.016 fatcat:6sgdar4lcfgmjp24u74u6qjjd4