English

A lower density operator for the Borel algebra

General Topology 2019-11-04 v1

Abstract

We prove that the existence of a Borel lower density operator (a Borel lifting) with respect to the σ\sigma-ideal of countable sets, for an uncountable Polish space, is equivalent to the Continuum Hypothesis.

Keywords

Cite

@article{arxiv.1903.02397,
  title  = {A lower density operator for the Borel algebra},
  author = {Marek Balcerzak and Szymon Głab},
  journal= {arXiv preprint arXiv:1903.02397},
  year   = {2019}
}
R2 v1 2026-06-23T07:59:54.660Z