English

Transferring Compactness

Logic 2024-04-29 v3

Abstract

We demonstrate that the technology of Radin forcing can be used to transfer compactness properties at a weakly inaccessible but not strong limit cardinal to a strongly inaccessible cardinal. As an application, relative to the existence of large cardinals, we construct a model of set theory in which there is a cardinal κ\kappa that is nn-dd-stationary for all nωn\in \omega but not weakly compact. This is in sharp contrast to the situation in the constructible universe LL, where κ\kappa being (n+1)(n+1)-dd-stationary is equivalent to κ\kappa being Πn1\mathbf{\Pi}^1_n-indescribable. We also show that it is consistent that there is a cardinal κ2ω\kappa\leq 2^\omega such that Pκ(λ)P_\kappa(\lambda) is nn-stationary for all λκ\lambda\geq \kappa and nωn\in \omega, answering a question of Sakai.

Keywords

Cite

@article{arxiv.2307.06910,
  title  = {Transferring Compactness},
  author = {Tom Benhamou and Jing Zhang},
  journal= {arXiv preprint arXiv:2307.06910},
  year   = {2024}
}

Comments

Accepted version