English

Specialising Trees With Small Approximations II

Logic 2023-07-19 v2

Abstract

We show that the existence of a well-known type of ideals on a regular cardinal λ\lambda implies a compactness property concerning the specialisability of a tree of height λ\lambda with no cofinal branches. We also use Neeman's method of side conditions to show that the existence of such ideals is consistent with stationarily many appropriate guessing models. These objects suffice to extend the main theorem of \cite{mhpr_spe}: one can generically specialise any branchless tree of height κ++\kappa^{++} with a <κ{<}\kappa-closed, κ+\kappa^{+}-proper, and κ++\kappa^{++}-preserving forcing, which has the κ+\kappa^+-approximation property.

Keywords

Cite

@article{arxiv.2206.00612,
  title  = {Specialising Trees With Small Approximations II},
  author = {Rahman Mohammadpour},
  journal= {arXiv preprint arXiv:2206.00612},
  year   = {2023}
}

Comments

It is incomplete!

R2 v1 2026-06-24T11:36:12.713Z