English

Generalized ordinal analysis and reflection principles in set theory

Logic 2023-12-21 v1

Abstract

It is widely claimed that the natural axiom systems\unicodex2013\unicode{x2013}including the large cardinal axioms\unicodex2013\unicode{x2013}form a well-ordered hierarchy. Yet, as is well-known, it is possible to exhibit non-linearity and ill-foundedness by means of \emph{ad hoc} constructions. In this paper we formulate notions of proof-theoretic strength based on set-theoretic reflection principles. We prove that they coincide with orderings on theories given by the generalized ordinal analysis of Pohlers. Accordingly, these notions of proof-theoretic strength engender genuinely well-ordered hierarchies. The reflection principles considered in this paper are formulated relative to G\"odel's constructible universe; we conclude with generalizations to other inner models.

Keywords

Cite

@article{arxiv.2312.12859,
  title  = {Generalized ordinal analysis and reflection principles in set theory},
  author = {Hanul Jeon and James Walsh},
  journal= {arXiv preprint arXiv:2312.12859},
  year   = {2023}
}

Comments

36 pages

R2 v1 2026-06-28T13:57:18.116Z