English

Reversible filters

General Topology 2018-09-19 v2

Abstract

A space is reversible if every continuous bijection of the space onto itself is a homeomorphism. In this paper we study the question of which countable spaces with a unique non-isolated point are reversible. By Stone duality, these spaces correspond to closed subsets in the \v{C}ech-Stone compactification of the natural numbers βω\beta\omega. From this, the following natural problem arises: given a space XX that is embeddable in βω\beta\omega, is it possible to embed XX in such a way that the associated filter of neighborhoods defines a reversible (or non-reversible) space? We give the solution to this problem in some cases. It is specially interesting whether the image of the required embedding is a weak PP-set.

Keywords

Cite

@article{arxiv.1601.04081,
  title  = {Reversible filters},
  author = {Alan Dow and Rodrigo Hernández-Gutiérrez},
  journal= {arXiv preprint arXiv:1601.04081},
  year   = {2018}
}
R2 v1 2026-06-22T12:30:30.670Z