Article ID Journal Published Year Pages File Type
4661177 Topology and its Applications 2006 10 Pages PDF
Abstract

It is well known that every pair of disjoint closed subsets F0,F1 of a normal T1-space X admits a star-finite open cover U of X such that, for every U∈U, either or holds. We define a T1-space X to be strongly base-normal if there is a base B for X with |B|=w(X) satisfying that every pair of disjoint closed subsets F0,F1 of X admits a star-finite cover B′ of X by members of B such that, for every B∈B′, either or holds. We prove that there is a base-normal space which is not strongly base-normal. Moreover, we show that Rudin's Dowker space is strongly base-(collectionwise)normal. Strong zero-dimensionality on base-normal spaces are also studied.

Related Topics
Physical Sciences and Engineering Mathematics Geometry and Topology