Four cardinals and their relations in ZF

Lorenz Halbeisen*, Riccardo Plati, Salome Schumacher, Saharon Shelah

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

For a set M, fin(M) denotes the set of all finite subsets of M, M2 denotes the Cartesian product M×M, [M]2 denotes the set of all 2-element subsets of M, and seq1-1(M) denotes the set of all finite sequences without repetition which can be formed with elements of M. Furthermore, for a set S, let |S| denote the cardinality of S. Under the assumption that the four cardinalities |[M]2|, |M2|, |fin(M)|, |seq1-1(M)| are pairwise distinct and pairwise comparable in ZF, there are six possible linear orderings between these four cardinalities. We show that at least five of the six possible linear orderings are consistent with ZF.

Original languageEnglish
Article number103200
JournalAnnals of Pure and Applied Logic
Volume174
Issue number2
DOIs
StatePublished - Feb 2023

Bibliographical note

Publisher Copyright:
© 2022 The Author(s)

Keywords

  • Cardinals in ZF
  • Consistency results
  • Permutation models

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