English

Hyperspaces of the double arrow

General Topology 2024-04-23 v1

Abstract

Let A\mathbb{A} and S\mathbb{S} denote the double arrow of Alexandroff and the Sorgenfrey line, respectively. We show that for any n1n\geq 1, the space of all unions of at most nn closed intervals of A\mathbb{A} is not homogeneous. We also prove that the spaces of non-trivial convergent sequences of A\mathbb{A} and S\mathbb{S} are homogeneous. This partially solves an open question of A. Arhangel'ski\v{i}. In contrast, we show that the space of closed intervals of S\mathbb{S} is homogeneous.

Cite

@article{arxiv.2404.13741,
  title  = {Hyperspaces of the double arrow},
  author = {Sebastián Barría},
  journal= {arXiv preprint arXiv:2404.13741},
  year   = {2024}
}

Comments

9 pages

R2 v1 2026-06-28T16:01:30.123Z