English

Grey subsets of Polish spaces

Logic 2015-03-19 v3

Abstract

We develop the basics of an analogue of descriptive set theory for functions on a Polish space XX. We use this to define a version of the small index property in the context of Polish topometric groups, and show that Polish topometric groups with ample generics have this property. We also extend classical theorems of Effros and Hausdorff to the topometric context.

Keywords

Cite

@article{arxiv.1103.2762,
  title  = {Grey subsets of Polish spaces},
  author = {Itaï Ben Yaacov and Julien Melleray},
  journal= {arXiv preprint arXiv:1103.2762},
  year   = {2015}
}
R2 v1 2026-06-21T17:39:22.977Z