English

A note on partitions of groups

Group Theory 2014-08-26 v1

Abstract

Every infinite group GG of regular cardinality can be partitioned G=A1A2G=A_1\cup A_2 so that GFA1G\neq FA_1, GFA2G\neq FA_2 for every subset FGF\subset G of cardinality F<G|F|<|G|. The first author asked whether the same is true for each group GG of singular cardinality. We show that an answer depends on the algebraic structure of GG. In particular, this is so for each free group but the statement does not hold for every Abelian group GG of singular cardinality. As an application, we prove that every Abelian group of singular cardinality k admits maximal translation invariant k-bounded topology that impossible for all groups of regular cardinality.

Keywords

Cite

@article{arxiv.1408.5607,
  title  = {A note on partitions of groups},
  author = {Igor Protasov and Sergii Slobodianiuk},
  journal= {arXiv preprint arXiv:1408.5607},
  year   = {2014}
}
R2 v1 2026-06-22T05:38:01.357Z