| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 6424651 | Topology and its Applications | 2015 | 8 Pages |
Abstract
A space X is said to be monotonically Lindelöf if for any open cover U of X, there exists a countable open cover rU such that rU refines U and if an open cover V of X refines U, then rV refines rU. Gruenhage shows that every Lindelöf first-countable GO-space is monotonically Lindelöf. In the paper we obtain the following result:A Lindelöf GO-space X is monotonically Lindelöf if and only if(1)X has no subspace homeomorphic to a stationary subset of a regular ordinal ⩾Ï1;(2)the closure of the set of all points with character Ï1 is monotonically Lindelöf.
Related Topics
Physical Sciences and Engineering
Mathematics
Geometry and Topology
Authors
Yin-Zhu Gao, Wei-Xue Shi,