English

The Ramified Analytical Hierarchy using Extended Logics

Logic 2018-08-14 v1

Abstract

The use of Extended Logics to replace ordinary second order definability in Kleene's {\em Ramified Analytical Hierarchy} is investigated. This mirrors a similar investigation of Kennedy, Magidor and V\"a\"an\"anen \cite{KeMaVa2016} where G\"odel's universe LL of constructible sets is subjected to similar variance. Enhancing second order definability allows models to be defined which may or may not coincide with the original Kleene hierarchy in domain. Extending the logic with game quantifiers, and assuming strong axioms of infinity, we obtain {\em minimal correct} models of analysis. A wide spectrum of models can be so generated from abstract definability notions: one may take an abstract Spector Class and extract an extended logic for it. The resultant structure is then a minimal model of the given kind of definability.

Keywords

Cite

@article{arxiv.1808.03814,
  title  = {The Ramified Analytical Hierarchy using Extended Logics},
  author = {Philip Welch},
  journal= {arXiv preprint arXiv:1808.03814},
  year   = {2018}
}

Comments

To appear in the Bulletin for Symbolic Logic

R2 v1 2026-06-23T03:30:52.204Z