Polymorphic Ordinal Notations

Fuente: arXiv
Enregistré dans:
Détails bibliographiques
Auteur principal: Towsner, Henry
Format: Preprint
Publié: 2025
Sujets:
Accès en ligne:
Tags: Ajouter un tag
Pas de tags, Soyez le premier à ajouter un tag!
_version_ 1866918063787474944
author Towsner, Henry
author_facet Towsner, Henry
contents We give an alternative presentation of the ordinal notation at the strength of $Π^1_1-CA_0$ which allows the "uncountable" notation $Ω$ to be interpreted "polymorphically" - that is, we allow the notation to be interpreted as different cardinals depending on their context. This gives us a way to represent functions on ordinals within our ordinal notation system. We then use this idea to present an ordinal notation system for a system a bit weaker than parameter-free $Π^1_2-CA_0$.
format Preprint
id arxiv_https___arxiv_org_abs_2504_02131
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Polymorphic Ordinal Notations
Towsner, Henry
Logic
We give an alternative presentation of the ordinal notation at the strength of $Π^1_1-CA_0$ which allows the "uncountable" notation $Ω$ to be interpreted "polymorphically" - that is, we allow the notation to be interpreted as different cardinals depending on their context. This gives us a way to represent functions on ordinals within our ordinal notation system. We then use this idea to present an ordinal notation system for a system a bit weaker than parameter-free $Π^1_2-CA_0$.
title Polymorphic Ordinal Notations
topic Logic
url https://arxiv.org/abs/2504.02131