In this paper,we give some new characterizations on sn-metrizable spaces,using the concepts of compact-covering mappings,point-star networks and CF families.
本文利用紧覆盖映射、点星网、CF族的概念,给出了sn可度量空间的新刻画。
This paper shows that weakly hereditarily closure-preserving families is CF*-families.
证明了弱遗传闭包保持集族是CF*集族。