English

Borel Tukey morphisms and combinatorial cardinal invariants of the continuum

Logic 2019-08-16 v2

Abstract

We discuss the Borel Tukey ordering on cardinal invariants of the continuum. We observe that this ordering makes sense for a larger class of cardinals than has previously been considered. We then provide a Borel version of a large portion of van Douwen's diagram. For instance, although the usual proof of the inequality pb\mathfrak p\leq\mathfrak b does not provide a Borel Tukey map, we show that in fact there is one. Afterwards, we revisit a result of Mildenberger concerning a generalization of the unsplitting and splitting numbers. Lastly, we show that the inclusion ordering on P(ω)\mathcal P(\omega) embeds into the Borel Tukey ordering on cardinal invariants.

Keywords

Cite

@article{arxiv.1208.1788,
  title  = {Borel Tukey morphisms and combinatorial cardinal invariants of the continuum},
  author = {Samuel Coskey and Tamás Mátrai and Juris Steprāns},
  journal= {arXiv preprint arXiv:1208.1788},
  year   = {2019}
}