English

The Dyck and the Preiss separation uniformly

Logic 2017-03-21 v1

Abstract

We are concerned with two separation theorems about analytic sets by Dyck and Preiss, the former involves the positively-defined subsets of the Cantor space and the latter the Borel-convex subsets of finite dimensional Banach spaces. We show by introducing the corresponding separation trees that both of these results admit a constructive proof. This enables us to give the uniform version of the separation theorems, and derive as corollaries the results, which are analogous to the fundamental fact "HYP is effectively bi-analytic" provided by the Souslin-Kleene Theorem.

Keywords

Cite

@article{arxiv.1703.06480,
  title  = {The Dyck and the Preiss separation uniformly},
  author = {Vassilios Gregoriades},
  journal= {arXiv preprint arXiv:1703.06480},
  year   = {2017}
}

Comments

42 pages, preprint

R2 v1 2026-06-22T18:50:06.813Z