Intersection properties of open sets, II.
逻辑
2016-09-06 v1
摘要
A topological space is called P_2 ( P_3, P_{<omega} ) if and only if it does not contain two (three, finitely many) uncountable open sets with empty intersection. We show that (i) there are 0-dimensional P_{<omega} spaces of size 2^omega, (ii) there are compact P_{<omega} spaces of size omega_1, (iii) the existence of a Psi-like examples for a compact P_{<omega} space of size omega_1 is independent of ZFC, (iv) it is consistent that 2^omega is as large as you wish but every first countable (and so every compact) P_2 space has cardinality<=omega_1.
引用
@article{arxiv.math/9605209,
title = {Intersection properties of open sets, II.},
author = {I. Juhász and Zs. Nagy and Lajos Soukup and Z. Szentmiklóssy},
journal= {arXiv preprint arXiv:math/9605209},
year = {2016}
}