郑州大学学报（理学版）2017，Vol.49Issue(3)：5-8,4.DOI:10.13705/j.issn.1671-6841.2017029
关于(X)0-sn-网的一些性质
Some Properties on (X)0-sn- networks
摘要
Abstract
Let a topological space X be an (X)0-sn- weakly first-countable space,and P be a point-countable cs-network for X.The following results were obtained.If P was closed under finite intersections,then there existsed a subfamily B of P such that B was an (X)0-sn- network for X.It was also proved that the followings were equivalent for a topological space X: 1) X had a point-countable (X)0-sn- network.2) There was a metric space M and a sequentially quotient,countable-to-one map f:M→X.3) There was a metric space M and a sequentially quotient,s-map f:M→X such that (e)f-1(x)≤ω for each x∈X.关键词
(X)0-sn-网/(X)0-sn-弱第一可数/cs-网/弱基Key words
(X)0-sn-network/(X)0-sn-weakly first-countable/cs-network/weak bases分类
数理科学引用本文复制引用
刘士琴..关于(X)0-sn-网的一些性质[J].郑州大学学报（理学版）,2017,49(3):5-8,4.基金项目
国家自然科学基金资助项目(11301159) （11301159）
广西高校重点实验室项目(2016CSOBDP0004). （2016CSOBDP0004）
