English

Hereditarily separable groups and monochromatic uniformization

Logic 2007-05-23 v1 Group Theory

Abstract

We give a combinatorial equivalent to the existence of a non-free hereditarily separable group of cardinality aleph_1. This can be used, together with a known combinatorial equivalent of the existence of a non-free Whitehead group, to prove that it is consistent that every Whitehead group is free but not every hereditarily separable group is free. We also show that the fact that Z is a p.i.d. with infinitely many primes is essential for this result.

Cite

@article{arxiv.math/0406552,
  title  = {Hereditarily separable groups and monochromatic uniformization},
  author = {Paul C. Eklof and Alan H. Mekler and Saharon Shelah},
  journal= {arXiv preprint arXiv:math/0406552},
  year   = {2007}
}