English

Superatomic Boolean algebras constructed from strongly unbounded functions

Logic 2015-03-17 v1

Abstract

Using Koszmider's strongly unbounded functions, we show the following consistency result: Suppose that κ,λ\kappa,\lambda are infinite cardinals such that κ+++λ\kappa^{+++} \leq \lambda, κ<κ=κ\kappa^{<\kappa}=\kappa and 2κ=κ+2^{\kappa}= \kappa^+, and η\eta is an ordinal with κ+η<κ++\kappa^+\leq \eta <\kappa^{++} and cf(η)=κ+cf(\eta) = \kappa^+. Then, in some cardinal-preserving generic extension there is a superatomic Boolean algebra BB such that - ht(B)=η+1ht(B) = \eta + 1, - the cardinality of the α\alphath level of BB is κ\kappa for every α<η\alpha <\eta, - and the cardinality of the η\etath level of BB is λ\lambda Especially, \<ωω1\concatenation\<ω3\<{\omega}\>_{{\omega}_1}\concatenation \<{\omega}_3\> and \<ω1ω2\concatenation\<ω4\<{\omega}_1\>_{{\omega}_2}\concatenation \<{\omega}_4\> can be cardinal sequences of superatomic Boolean algebras.

Keywords

Cite

@article{arxiv.1004.4798,
  title  = {Superatomic Boolean algebras constructed from strongly unbounded functions},
  author = {Juan Carlos Martinez and Lajos Soukup},
  journal= {arXiv preprint arXiv:1004.4798},
  year   = {2015}
}

Comments

13 pages

R2 v1 2026-06-21T15:15:27.107Z