English

A common extension of Lindel\"of, H-closed and ccc

General Topology 2020-02-10 v1

Abstract

The inequality X2χ(X)|X| \leq 2^{\chi(X)} has been proved to be true for Lindel\"of spaces (Arhangel'ski\u\i, 1969), HH-closed spaces (Dow-Porter, 1982) and ccc spaces (Hajnal-Ju\'asz 1967), by quite different arguments. We present a common extension of all these properties which allows us to give a unified proof of these three theorems.

Keywords

Cite

@article{arxiv.2002.02719,
  title  = {A common extension of Lindel\"of, H-closed and ccc},
  author = {Angelo Bella},
  journal= {arXiv preprint arXiv:2002.02719},
  year   = {2020}
}