English

The hyperspace of non-blockers of singletons, all the possible examples

General Topology 2022-12-15 v1

Abstract

Given a metric continuum XX, a nonempty proper closed subspace BB of XX, does not block a point pXBp\in X\setminus B provided that the union of all subcontinua of XX containing pp and contained in XBX\setminus B is a dense subset of XX. The collection of all nonempty proper closed subspaces BB of XX such that BB does not block any element of XBX\setminus B is denoted by NB(F1(X))NB(F_{1}(X)). In this paper we prove that for each completely metrizable and separable space ZZ, there exists a continuum XX such that ZZ is homeomorphic to NB(F1(X))NB(F_{1}(X)). This answers a series of questions by Camargo, Capul\'in, Casta\=neda-Alvarado and Maya.

Keywords

Cite

@article{arxiv.2212.07077,
  title  = {The hyperspace of non-blockers of singletons, all the possible examples},
  author = {Alejandro Illanes and Benjamin Vejnar},
  journal= {arXiv preprint arXiv:2212.07077},
  year   = {2022}
}