English

Wijsman hyperspaces of non-separable metric spaces

General Topology 2015-03-27 v1

Abstract

Given a metric space X,ρ\langle X,\rho \rangle, consider its hyperspace of closed sets CL(X)CL(X) with the Wijsman topology τW(ρ)\tau_{W(\rho)}. It is known that CL(X),τW(ρ)\langle{CL(X),\tau_{W(\rho)}}\rangle is metrizable if and only if XX is separable and it is an open question by Di Maio and Meccariello whether this is equivalent to CL(X),τW(ρ)\langle{CL(X),\tau_{W(\rho)}}\rangle being normal. In this paper we prove that if the weight of XX is a regular uncountable cardinal and XX is locally separable, then CL(X),τW(ρ)\langle{CL(X),\tau_{W(\rho)}}\rangle is not normal. We also solve some questions by Cao, Junnilla and Moors regarding isolated points in Wijsman hyperspaces.

Keywords

Cite

@article{arxiv.1312.1705,
  title  = {Wijsman hyperspaces of non-separable metric spaces},
  author = {Rodrigo Hernández-Gutiérrez and Paul Szeptycki},
  journal= {arXiv preprint arXiv:1312.1705},
  year   = {2015}
}