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N0-sn-网的注记
引用本文:王培,葛洵,刘士琴.N0-sn-网的注记[J].山东大学学报(自然科学版),2011(4):118-120.
作者姓名:王培  葛洵  刘士琴
作者单位:[1]玉林师范学院数学与计算机科学系,广西玉林537000 [2]江苏科技大学张家港校区,江苏张家港215600 [3]衡水学院数学与计算机学院,河北衡水053000
基金项目:广西自然科学基金资助项目(0728035);玉林师范学院青年基金资助项目(2009YJQN14)
摘    要:利用序列商映射建立了具有可数N0-sn-网的空间与可分度量空间之间的联系,讨论了可分度量空间的可数到一、序列商映像。证明了在序列空间中,下列叙述等价:(1)X有σ-离散的N0-sn-网;(2)X有σ-局部有限的N0-sn-网;(3)X有σ-遗传闭包保持的N0-sn-网;(4)X是N0-sn-弱第一可数的N-空间;(5)X有由闭子集构成的σ-紧有限的N0-sn-网。

关 键 词:N0-sn-网  N0-弱基  序列商映射  可数到一映射

A note on N0-sn-network
WANG Pei,GE Xun,LIU Shi-qin.A note on N0-sn-network[J].Journal of Shandong University(Natural Science Edition),2011(4):118-120.
Authors:WANG Pei  GE Xun  LIU Shi-qin
Institution:1. Department of Mathematics and Computer Science, Yulin Normal University, Yulin 537000, Guangxi, China; 2. Campus of Zhangjiagang, Jiangsu University of Science and Technology, Zhangjiagang 215600, Jiangsu, China; 3. Department of Mathematics and Computer, Hengshui College, Hengshui 053000, Hebei, China)
Abstract:The relations between a space with countable R0-sn-network and separable metric spaces are established by means of sequentially quotient map, and separable metric space is discussed by sequentially quotient and countable-to-one maps. The following are equivalent and proved for a sequence space X: ( 1 ) X has ao--discrete Ro-sn-network, (2) X has a o--locally finite N0-sn-network, (3) X has a tr-hereditadly closure-preserving N0-sn-network, (4) X is an Ro-sn- weakly first-countable and R-space, and (5) X has an tr-compact-finitei, N0-sn-network consisting of closed subsets.
Keywords:N0-sn-network  N0-weak base  sequentially quotient map  countable-to-one maps
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