English

Homomorphism reductions on Polish groups

Logic 2016-10-19 v1

Abstract

In an earlier paper, we introduced the following pre-order on the subgroups of a given Polish group: if GG is a Polish group and H,LGH,L \subseteq G are subgroups, we say HH is {\em homomorphism reducible} to LL iff there is a continuous group homomorphism φ:GG\varphi : G \rightarrow G such that H=φ1(L)H = \varphi^{-1} (L). We previously showed that there is a KσK_\sigma subgroup, LL, of the countable power of any locally compact Polish group, GG, such that every KσK_\sigma subgroup of GωG^\omega is homomorphism reducible to LL. In the present work, we show that this fails in the countable power of the group of increasing homeomorphisms of the unit interval.

Keywords

Cite

@article{arxiv.1610.05405,
  title  = {Homomorphism reductions on Polish groups},
  author = {Konstantinos A. Beros},
  journal= {arXiv preprint arXiv:1610.05405},
  year   = {2016}
}
R2 v1 2026-06-22T16:23:39.823Z