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(1)X是W-Like空间,则bX是Lindel?f空间;(2)若Xn,n∈N是W-Like空间,则∏n∈NXn是Lindel?f空间. 相似文献
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1 IntroductionLet P be of the four properties of "PF" (point--finite), "LF" (locally finite), "CP" (clOSurerpreserving) or "HCP" (hereditarily closure--preserving). The concept of P--netted was in-troduced in [l]. In [l], the authors pointed out that stratifiable Fa--metrizable spaces areLFnetted spaces, and every normal a--space has a aediscrete PF--regUlar closed net. Theysaid that they did not lcnow whetlier every a--space has a closed a--lacally finite PFregularnet. In this note, … 相似文献
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W-Like空间可数积的Lindel(o)f性质 总被引:1,自引:0,他引:1
(1)X是W┐Like空间,则bX是Lindelof空间;(2)若Xn,n∈N是W┐Like空间,则∏n∈NXn是Lindelof空间. 相似文献
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Some characterizations of paracompact maps are given in this note, and some equivalent statements of collectionwise normal maps are discussed. And also we show that if f : X→Y is a closed collectionwise normal map, and f^-1(y) is a semistratifiable subspace of X for any y ∈ Y, then f is a paracompact map. 相似文献
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引入了两个很有联系的空间类JHB-空间与强J HB-空间,分别推广了J-空间与强J-空间.讨论了J-空间、强J-空间、J HB-空间及强JHB-空间类间的相包含关系及此四空间类逆包含的条件,还得到了JHB-空间的内部刻画,并证明了若对每个α∈S,Xα.都是非紧的连通空间,则积空间∏α∈S Xα是强J-空间。 相似文献
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In the first part of this note, we mainly prove that monotone metacompactness is hereditary with respect to closed subspaces and open Fó-subspaces. For a generalized ordered (GO)-space X, we also show that X is monotonically metacompact if and only if its closed linearly ordered extension X* is monotonically metacompact. We also point out that every non-Archimedean space X is monotonically ultraparacompact. In the second part of this note, we give an alternate proof of the result that McAuley space is paracompact and metacompact. 相似文献
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本文回答了关于MCM空间遗传性的一个问题,讨论了k-MCM空间是k半层空间的条件,得到了一些用g函数刻划的度量化定理.主要结论有:MCM空间是关于Fσ子空间遗传的;在正规空间类中,q空间(ωN空间,k-MCM空间)是关于开Fσ子空间遗传的;如果X是具有Gδ对角线的正则次中紧 k-MCM空间,则X是k半层空间;X是可度量化空间的充要条件是存在X上的g函数满足对X中任意不相交的闭集F与紧集C,都有某个n∈ω,使得(∪x∈F g(n,x))∩(∪y∈C g(n,y))=(?). 相似文献
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彭良雪 《数学物理学报(A辑)》2006,26(5):653-658
人们知道每个C-似空间是 D -空间, 且每个正则弱θ -可加细 C-散布空间也是D -空间。上述空间类的积空间还是D -空间吗?在这篇文章中作者讨论了该问题, 得到如下结论:正则弱θ -可加细空间的有限积是D -空间; 正则Lindel\"of C-散布空间的可数积是D -空间 相似文献