English

Indestructibility properties of remarkable cardinals

Logic 2015-06-10 v2

Abstract

Remarkable cardinals were introduced by Schindler, who showed that the existence of a remarkable cardinal is equiconsistent with the assertion that the theory of L(R)L(\mathbb R) is absolute for proper forcing. Here, we study the indestructibility properties of remarkable cardinals. We show that if κ\kappa is remarkable, then there is a forcing extension in which the remarkability of κ\kappa becomes indestructible by all <κ\lt\kappa-closed κ\leq\kappa-distributive forcing and all two-step iterations of the form Add(κ,θ)R˙{\rm Add}(\kappa,\theta)*\dot{\mathbb R}, where R˙\dot{\mathbb R} is forced to be <κ\lt\kappa-closed and κ\leq\kappa-distributive. In the process, we introduce the notion of a remarkable Laver function and show that every remarkable cardinal carries such a function. We also show that remarkability is preserved by the canonical forcing of the GCH{\rm GCH}.

Keywords

Cite

@article{arxiv.1411.2551,
  title  = {Indestructibility properties of remarkable cardinals},
  author = {Yong Cheng and Victoria Gitman},
  journal= {arXiv preprint arXiv:1411.2551},
  year   = {2015}
}

Comments

21 pages. Commentary concerning this article can be made at http://boolesrings.org/victoriagitman/2014/09/17/indestructible-remarkable-cardinals/