English

Cardinal invariants of cellular-Lindelof spaces

General Topology 2019-03-04 v2

Abstract

A space XX is said to be "cellular-Lindel\"of" if for every cellular family U\mathcal{U} there is a Lindel\"of subspace LL of XX which meets every element of U\mathcal{U}. Cellular-Lindel\"of spaces generalize both Lindel\"of spaces and spaces with the countable chain condition. Solving questions of Xuan and Song, we prove that every cellular-Lindel\"of monotonically normal space is Lindel\"of and that every cellular-Lindel\"of space with a regular GδG_\delta-diagonal has cardinality at most 2c2^\mathfrak{c}. We also prove that every normal cellular-Lindel\"of first-countable space has cardinality at most continuum under 2<c=c2^{<\mathfrak{c}}=\mathfrak{c} and that every normal cellular Lindel\"of space with a GδG_\delta-diagonal of rank 22 has cardinality at most continuum.

Keywords

Cite

@article{arxiv.1811.00660,
  title  = {Cardinal invariants of cellular-Lindelof spaces},
  author = {Angelo Bella and Santi Spadaro},
  journal= {arXiv preprint arXiv:1811.00660},
  year   = {2019}
}