摘要
本文给出一个反例,证明正则性、完全正则性、正规性及完全正规性均不是半拓扑性质。
A simple example, which shows that the regularity, complete regularity, normality and complete normality are not semitopological properties, is constructed.
关键词
半开集
半拓扑性质
无处稠密集
Semiopen set, semitopological property, Nowhere dense set.
