Sh:1021

• Mildenberger, H., & Shelah, S. The cofinality of the symmetric group and the cofinality of ultrapowers. Preprint.
• Abstract:
  We prove that {\mathfrak{{mcf}}} < {\rm cf} ({\rm{Sym}(\omega)}) and {\mathfrak{{mcf}}} > {\rm cf}({\rm{Sym}(\omega)})= {\mathfrak{{b}}} are both consistent relative to ZFC. This answers a question from [BanakhRepovsZdomskyy] and from [MdSh:967].
• Version 2019-02-21_11 (25p)

@article{Sh:1021,
 author = {Mildenberger, Heike and Shelah, Saharon},
 title = {{The cofinality of the symmetric group and the cofinality of ultrapowers}}
}