On the strength of ultrafilters above choiceless large cardinals and their Prikry forcings

Fuente: arXiv
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Main Authors: Adkisson, William, Neria, Omer Ben
Format: Preprint
Published: 2025
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author Adkisson, William
Neria, Omer Ben
author_facet Adkisson, William
Neria, Omer Ben
contents We study the strength of well-founded ultrafilters on ordinals above choiceless large cardinals and their associated Prikry forcings. Gabriel Goldberg showed that all but boundedly many regular cardinals above a rank Berkeley cardinal carry well-founded uniform ultrafilters. We prove several bounds on the large cardinal strength that is witnessed by such ultrafilters. We then extend the theory of Prikry forcing in this context and place limits on the cardinals that can be collapsed or singularized. Finally, we develop the notion of a tensor Prikry system, and use it to give new constructions for several consistency results in choiceless set theory. In particular, we build a new model in which all uncountable cardinals are singular.
format Preprint
id arxiv_https___arxiv_org_abs_2511_07622
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle On the strength of ultrafilters above choiceless large cardinals and their Prikry forcings
Adkisson, William
Neria, Omer Ben
Logic
We study the strength of well-founded ultrafilters on ordinals above choiceless large cardinals and their associated Prikry forcings. Gabriel Goldberg showed that all but boundedly many regular cardinals above a rank Berkeley cardinal carry well-founded uniform ultrafilters. We prove several bounds on the large cardinal strength that is witnessed by such ultrafilters. We then extend the theory of Prikry forcing in this context and place limits on the cardinals that can be collapsed or singularized. Finally, we develop the notion of a tensor Prikry system, and use it to give new constructions for several consistency results in choiceless set theory. In particular, we build a new model in which all uncountable cardinals are singular.
title On the strength of ultrafilters above choiceless large cardinals and their Prikry forcings
topic Logic
url https://arxiv.org/abs/2511.07622