English

Cofinality of the nonstationary ideal

Logic 2013-01-03 v1

Abstract

We show that the reduced cofinality of the nonstationary ideal NS_kappa on a regular uncountable cardinal kappa may be less than its cofinality, where the reduced cofinality of NS_kappa is the least cardinality of any family F of nonstationary subsets of kappa such that every nonstationary subset of kappa can be covered by less than κ\kappa many members of F.

Keywords

Cite

@article{arxiv.math/0210087,
  title  = {Cofinality of the nonstationary ideal},
  author = {Pierre Matet and Andrzej Rosłanowski and Saharon Shelah},
  journal= {arXiv preprint arXiv:math/0210087},
  year   = {2013}
}