English

Polish modules over subrings of $\mathbb Q$

Logic 2022-10-17 v1 Commutative Algebra

Abstract

We give a method of producing a Polish module over an arbitrary subring of Q\mathbb Q from an ideal of subsets of N\mathbb N and a sequence in N\mathbb N. The method allows us to construct two Polish Q\mathbb Q-vector spaces, UU and VV, such that -- both UU and VV embed into R\mathbb R but -- UU does not embed into VV and VV does not embed into UU, where by an embedding we understand a continuous Q\mathbb Q-linear injection. This construction answers a question of Frisch and Shinko. In fact, our method produces a large number of incomparable with respect to embeddings Polish Q\mathbb Q-vector spaces.

Keywords

Cite

@article{arxiv.2210.07989,
  title  = {Polish modules over subrings of $\mathbb Q$},
  author = {Dexuan Hu and Sławomir Solecki},
  journal= {arXiv preprint arXiv:2210.07989},
  year   = {2022}
}
R2 v1 2026-06-28T03:40:33.646Z