In this paper,we give an example of a Hausdorff centered-Lindelf space X such that St-l(X)=c^+,which negatively answers two questions rasied by Bonanzinga and Matveev.
文摘In this paper,we give an example of a Hausdorff centered-Lindelf space X such that St-l(X)=c^+,which negatively answers two questions rasied by Bonanzinga and Matveev.