English

An Ideal Zoo in the Baire Space

General Topology 2025-11-03 v1

Abstract

In this paper, we study the translations into the Baire space of several well-known σ\sigma-ideals and families originally defined on the Cantor space, using their combinatorial characterizations. These include the ideals of null sets, small sets, those generated by closed measure-zero sets, and the meager sets, leading to their "fake" analogues in the Baire space. We also parametrize families related to null sets by functions from ωω\omega^\omega. Several structural properties and relations between these families are investigated, including whether they form ideals, the existence of large chains and antichains, orthogonality, the κ\kappa-chain condition, and the determination of certain cardinal invariants.

Keywords

Cite

@article{arxiv.2510.27435,
  title  = {An Ideal Zoo in the Baire Space},
  author = {Łukasz Mazurkiewicz and Marcin Michalski and Szymon Żeberski},
  journal= {arXiv preprint arXiv:2510.27435},
  year   = {2025}
}