English

Uniquely universal sets in $\mathbb{R} \times \omega$ and $[0,1] \times \omega$

General Topology 2014-08-22 v1

Abstract

Let XX and YY be topological spaces. We say that X×YX\times Y satisfies the Uniquely Universal property (UU) iff there exists an open set UX×YU\subseteq X\times Y such that for every open set WYW\subseteq Y there is a unique cross section of UU with U(x)={yY:(x,y)U}=WU\left( x\right) =\left\{ y\in Y:\left( x,y\right) \in U\right\} =W. Arnold W. Miller in his paper \cite{1} posed the following two questions: 1. Does [0,1]×ω[ 0,1] \times \omega have UU? 2. Does R×ω \mathbb{R} \times \omega have UU? In this paper we present two constructions which give positive answers to both problems.

Keywords

Cite

@article{arxiv.1408.5015,
  title  = {Uniquely universal sets in $\mathbb{R} \times \omega$ and $[0,1] \times \omega$},
  author = {Alicja Krzeszowiec},
  journal= {arXiv preprint arXiv:1408.5015},
  year   = {2014}
}