Towers, mad families, and unboundedness

Vera Fischer, Wolfgang Wohofsky, Marlene Elisabeth Koelbing

Publications: Contribution to journalArticlePeer Reviewed

Abstract

We show that Hechler’s forcings for adding a tower and for adding a mad family can be represented as finite support iterations of Mathias forcings with respect to filters and that these filters are B-Canjar for any countably directed unbounded family B of the ground model. In particular, they preserve the unboundedness of any unbounded scale of the ground model. Moreover, we show that b=ω1 in every extension by the above forcing notions.
Original languageEnglish
Pages (from-to)811-830
Number of pages20
JournalArchive for Mathematical Logic
Volume62
Issue number5-6
Early online date12 Feb 2023
DOIs
Publication statusPublished - Jul 2023

Austrian Fields of Science 2012

  • 101013 Mathematical logic

Keywords

  • Canjar filters
  • Forcing
  • Maximal almost disjoint families
  • Towers
  • Unboundedness

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