English

Pseudocompact group topologies with no infinite compact subsets

Group Theory 2010-05-14 v3 General Topology

Abstract

We show that every Abelian group satisfying a mild cardinal inequality admits a pseudocompact group topology from which all countable subgroups inherit the maximal totally bounded topology (we say that such a topology satisfies property \h\h). Every pseudocompact Abelian group GG with cardinality G22\cc|G|\leq 2^{2^\cc} satisfies this inequality and therefore admits a pseudocompact group topology with property \h\h. Under the Singular Cardinal Hypothesis (SCH) this criterion can be combined with an analysis of the algebraic structure of pseudocompact groups to prove that every pseudocompact Abelian group admits a pseudocompact group topology with property \h\h. We also observe that pseudocompact Abelian groups with property \h\h contain no infinite compact subsets and are examples of Pontryagin reflexive precompact groups that are not compact.

Keywords

Cite

@article{arxiv.0812.5033,
  title  = {Pseudocompact group topologies with no infinite compact subsets},
  author = {Jorge Galindo and Sergio Macario},
  journal= {arXiv preprint arXiv:0812.5033},
  year   = {2010}
}

Comments

19 pages; In this version we work assuming SCH (Singular Cardinal Hypothesis), whereas in our previous version we had to assume GCH (Generalized Continuum Hypothesis). The general problem is still open in ZFC, but models avoiding SCH are much harder to come by. We thank professors W. W. Comfort and D. Dikranjan for their help concerning Example 5.9.

R2 v1 2026-06-21T11:56:34.146Z