English

The quasi-metrizability of hyperspaces

General Topology 2023-04-10 v1

Abstract

For a space XX, let (CL(X),τV)(CL(X), \tau_V), (CL(X),τlocfin)(CL(X), \tau_{locfin}) and (CL(X),τF)(CL(X), \tau_F) be the set CL(X)CL(X) of all nonempty closed subsets of XX which are endowed with Vietoris topology, locally finite topology and Fell topology respectively. We prove that (CL(X),τV)(CL(X), \tau_V) is quasi-metrizable if and only if XX is a separable metrizable space and the set of all non-isolated points of XX is compact, (CL(X),τlocfin)(CL(X), \tau_{locfin}) is quasi-metrizable or symmetrizable if and only if XX is metrizable and the set of all non-isolated points of XX is compact, and (CL(X),τF)(CL(X), \tau_F) is quasi-metrizable if and only if XX is hemicompact and metrizable. As an application, we give a negative answer to a Conjecture in \cite{LL2022}.

Keywords

Cite

@article{arxiv.2304.03455,
  title  = {The quasi-metrizability of hyperspaces},
  author = {Chuan Liu and Fucai Lin},
  journal= {arXiv preprint arXiv:2304.03455},
  year   = {2023}
}

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11 pages