Archive for Mathematical Logic

, Volume 30, Issue 1, pp 1–11 | Cite as

Groupwise density and related cardinals

  • Andreas Blass
Article

Abstract

We prove several theorems about the cardinal\(\mathfrak{g}\) associated with groupwise density. With respect to a natural ordering of families of nond-ecreasing maps fromω toω, all families of size\(< \mathfrak{g}\) are below all unbounded families. With respect to a natural ordering of filters onω, all filters generated by\(< \mathfrak{g}\) sets are below all non-feeble filters. If\(\mathfrak{u}< \mathfrak{g}\) then\(\mathfrak{b}< \mathfrak{u}\) and\(\mathfrak{g} = \mathfrak{d} = \mathfrak{c}\). (The definitions of these cardinals are recalled in the introduction.) Finally, some consequences deduced from\(\mathfrak{u}< \mathfrak{g}\) by Laflamme are shown to be equivalent to\(\mathfrak{u}< \mathfrak{g}\).

Keywords

Mathematical Logic Related Cardinal Unbounded Family 

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Copyright information

© Springer-Verlag 1990

Authors and Affiliations

  • Andreas Blass
    • 1
  1. 1.Mathematics DepartmentUniversity of MichiganAnn ArborUSA

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