English

Are $\mathfrak a$ and $\mathfrak d$ your cup of tea? Revisited

Logic 2021-08-10 v1

Abstract

This is a revised version (of late 2020) of [Sh:700], which is arXiv:math/0012170 . First point is noting that the proof of Theorem 4.3 in [Sh:700], which says that the proof giving the consistency b=d=u<a \mathfrak{b} = \mathfrak{d} = \mathfrak{u} < \mathfrak{a} also gives s=d \mathfrak{s} = \mathfrak{d} . The proof uses a measurable cardinal and a c.c.c. forcing so it gives large d \mathfrak{d} and assumes a large cardinal. Second point is adding to the results of \S2,\S3 which say that (in \S3 with no large cardinals) we can force 1<b=d<a {\aleph_1} < \mathfrak{b} = \mathfrak{d} < \mathfrak{a}. We like to have 1<sb=d<a {\aleph_1} < \mathfrak{s} \le \mathfrak{b} = \mathfrak{d} < \mathfrak{a} . For this we allow in \S2,\S3 the sets Kt K_t to be uncountable; this requires non-essential changes. In particular, we replace usually 0,1 {\aleph_0}, {\aleph_1} by σ, \sigma , \partial . Naturally we can deal with i \mathfrak{i} and similar invariants. Third we proofread the work again. To get s \mathfrak{s} we could have retained the countability of the member of the It I_t-s but the parameters would change with AIt A \in I_t, well for a cofinal set of them; but the present seems simpler. We intend to continue in [Sh:F2009].

Keywords

Cite

@article{arxiv.2108.03666,
  title  = {Are $\mathfrak a$ and $\mathfrak d$ your cup of tea? Revisited},
  author = {Saharon Shelah},
  journal= {arXiv preprint arXiv:2108.03666},
  year   = {2021}
}

Comments

revisited version of arXiv:math/0012170