English

Lonely points revisited

General Topology 2016-07-22 v1

Abstract

In our previous paper, Lonely points, we introduced the notion of a lonely point, due to P. Simon. A point pXp\in X is lonely if it is a limit point of a countable dense-in-itself set, not a limit point a countable discrete set and all countable sets whose limit point it is, form a filter. We use the space Gω{\mathcal G}_\omega from a paper of A. Dow, A.V. Gubbi and A. Szyma\'nski (Rigid Stone spaces within ZFC, Proc. Amer. Math. Soc. 102 (1988), no. 3, 745--748) to construct lonely points in ω\omega^*. This answers the question of P. Simon posed in our paper Lonely points (Lonely points in ω\omega^*, Topology Appl. 155 (2008), no. 16, 1766--1771).

Cite

@article{arxiv.1607.06273,
  title  = {Lonely points revisited},
  author = {Jonathan L. Verner},
  journal= {arXiv preprint arXiv:1607.06273},
  year   = {2016}
}
R2 v1 2026-06-22T15:00:24.142Z