1. Remarks on discretely absolutely star-Lindelöf spaces
- Creator:
- Song, Yan-Kui
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- countably compact space, star-Lindelöf space, absolutely star-Lindelöf space, and discretely absolutely star-Lindelöf
- Language:
- English
- Description:
- In this paper, we prove the following statements: \item {(1)} There exists a Hausdorff Lindelöf space $X$ such that the Alexandroff duplicate $A(X)$ of $X$ is not discretely absolutely star-Lindelöf. \item {(2)} If $X$ is a regular Lindelöf space, then $A(X)$ is discretely absolutely star-Lindelöf. \item {(3)} If $X$ is a normal discretely star-Lindelöf space with $e(X)< \omega _1$, then $A(X)$ is discretely absolutely star-Lindelöf.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public