English

Zero-dimensional $\sigma$-homogeneous spaces

General Topology 2023-07-18 v2 Logic

Abstract

All spaces are assumed to be separable and metrizable. Ostrovsky showed that every zero-dimensional Borel space is σ\sigma-homogeneous. Inspired by this theorem, we obtain the following results: assuming AD\mathsf{AD}, every zero-dimensional space is σ\sigma-homogeneous; assuming AC\mathsf{AC}, there exists a zero-dimensional space that is not σ\sigma-homogeneous; assuming V=L\mathsf{V=L}, there exists a coanalytic zero-dimensional space that is not σ\sigma-homogeneous. Along the way, we introduce two notions of hereditary rigidity, and give alternative proofs of results of van Engelen, Miller and Steel. It is an open problem whether every analytic zero-dimensional space is σ\sigma-homogeneous.

Keywords

Cite

@article{arxiv.2107.07747,
  title  = {Zero-dimensional $\sigma$-homogeneous spaces},
  author = {Andrea Medini and Zoltán Vidnyánszky},
  journal= {arXiv preprint arXiv:2107.07747},
  year   = {2023}
}

Comments

22 pages

R2 v1 2026-06-24T04:15:18.597Z