A Failure of $Π^1_{n+3}$-Reduction in the Presence of $Σ^1_{n+3}$-Separation

Fuente: arXiv
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1. Verfasser: Hoffelner, Stefan
Format: Preprint
Veröffentlicht: 2023
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author Hoffelner, Stefan
author_facet Hoffelner, Stefan
contents We show that one can force over $L$ that $Σ^1_3$-separation holds, while $Π^1_3$-reduction fails, thus separating these two principles for the first time. The construction can be lifted to canonical inner models $M_n$ with $n$-many Woodin cardinals, yielding that assuming the existence of $M_n$, $Σ^1_{n+3}$-separation can hold, yet $Π^1_{n+3}$-reduction fails.
format Preprint
id arxiv_https___arxiv_org_abs_2312_02540
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle A Failure of $Π^1_{n+3}$-Reduction in the Presence of $Σ^1_{n+3}$-Separation
Hoffelner, Stefan
Logic
03E15, 03E35, 03E45
We show that one can force over $L$ that $Σ^1_3$-separation holds, while $Π^1_3$-reduction fails, thus separating these two principles for the first time. The construction can be lifted to canonical inner models $M_n$ with $n$-many Woodin cardinals, yielding that assuming the existence of $M_n$, $Σ^1_{n+3}$-separation can hold, yet $Π^1_{n+3}$-reduction fails.
title A Failure of $Π^1_{n+3}$-Reduction in the Presence of $Σ^1_{n+3}$-Separation
topic Logic
03E15, 03E35, 03E45
url https://arxiv.org/abs/2312.02540