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1.
关于1-序列商映射   总被引:3,自引:1,他引:3  
谷建胜 《数学研究》2003,36(3):305-308,313
引进了1-序列商映射,证明了1-序列商映射象保持sm-第一可数空间.作为这一结果的一个应用,本文证明了几乎开,闭映射保持度量空间,g-度量空间,sm-度量空间.此外本文还证明了度量空间上的1-序列商,紧映射是1-序列覆盖映射.这些结果改进并推广了广义度量空间映射象的有关理论.  相似文献   

2.
在一般拓扑空间中,引入了序列紧空间的统计定义并讨论其相应的拓扑性质,深化了拓扑群与可度量化空间中关于序列紧空间的一些结果.  相似文献   

3.
对推理闭包空间之间的关系进行了研究。结合拓扑学的思想和方法,在推理闭包空间之间引入了连续映射和商映射的概念,讨论了连续映射和商映射的基本性质以及它们之间的关系。为建立推理闭包空间范畴作了必要的准备工作。  相似文献   

4.
整理了关于商映射以及乘积空间的一些性质,得出了关于两个映射的乘积成为商映射的若干充分条件.  相似文献   

5.
关于三商映射   总被引:1,自引:1,他引:0  
林寿 《数学进展》1998,27(2):97-102
三商映射是完备映射和开映射的共同推广。本文综述三商映射的理论,论术这三商映射,开映射,紧覆盖映射,诱导完备映之间的一些转换关系,提出了几个供进一步研究的问题。  相似文献   

6.
研究了统计版本的的序列空间和Frechet-Urysohn空间,获得了一些有趣的性质.  相似文献   

7.
序列连通空间   总被引:6,自引:0,他引:6  
黄琴 《数学研究》2005,38(2):157-162
序列连通性具有许多相似于连通的性质.本文讨论了拓扑空间的序列连通性,并给出了序列连通空间的刻面及其性质.  相似文献   

8.
G序列紧空间     
基于G方法,在一般的集合中引入了G序列紧集,讨论了其基本性质,研究了在拓扑空间下其与序列紧,可数紧之间的关系,并论证了将方法定义为理想收敛时,G序列紧空间的应用.推广了序列紧与可数紧的一些经典结果.  相似文献   

9.
Orlicz序列空间的弱收敛序列系数   总被引:3,自引:0,他引:3  
本文给出了Orlicz序列空间的弱收敛序列系数的表达式.  相似文献   

10.
岳修奎 《数学季刊》2002,17(4):20-26
这篇论文刻画了 (Ap,α,lq) (0

0 ,p ≤ q≤∞ )的特征 ,作为其推论 ,获得了 (Al;lq)、(Hp,lq)、(Gp,lq)和 (Bp,lq) (0

相似文献   


11.
It is well known that a (linear) operator between Banach spaces is completely continuous if and only if its adjoint takes bounded subsets of Y* into uniformly completely continuous subsets, often called (L)-subsets, of X*. We give similar results for differentiable mappings. More precisely, if UX is an open convex subset, let be a differentiable mapping whose derivative is uniformly continuous on U-bounded subsets. We prove that f takes weak Cauchy U-bounded sequences into convergent sequences if and only if f takes Rosenthal U-bounded subsets of U into uniformly completely continuous subsets of . As a consequence, we extend a result of P. Hájek and answer a question raised by R. Deville and E. Matheron. We derive differentiable characterizations of Banach spaces not containing 1 and of Banach spaces without the Schur property containing a copy of 1. Analogous results are given for differentiable mappings taking weakly convergent U-bounded sequences into convergent sequences. Finally, we show that if X has the hereditary Dunford–Pettis property, then every differentiable function as above is locally weakly sequentially continuous.  相似文献   

12.
Some fixed-point theorems are established for weakly contractive operators. These results will then be used to establish existence principles for functional, differential, and integral equations.  相似文献   

13.
Summary We discuss the relationship between two different sequential connectedness, and prove that sequential connectedness is countably multiplicative.  相似文献   

14.
In this paper we have introduced the statistically localized sequences in metric spaces and investigate basic properties of the statistically localized sequences. Also we have obtained some necessary and sufficient conditions for a localized sequence to be a statistically Cauchy sequence. It is also defined uniformly statistically localized sequences on metric spaces and its relation with statistically Cauchy sequences has been investigated.  相似文献   

15.
Statistically convergent difference double sequence spaces   总被引:1,自引:0,他引:1  
In this article we define the notion of statistically convergent difference double sequence spaces. We examine the spaces 2l∞(△, q), 2c(△, q), 2cB(△, q), 2cR(△, q), 2cBR(△,q) etc. being symmetric, solid, monotone, etc. We prove some inclusion results too.  相似文献   

16.
17.
Main results: A pseudostratifiable symmetrizable space possesses a symmetric with weak Cauchy condition. A space is strongly symmetrizable if and only if it is a pseudo-open II-image of a metric space. There exists a zero-dimensional symmetrizable space without a symmetric with weak Cauchy condition.All spaces satisfy the axiom T1.Translated from Matematicheskie Zametki, Vol. 14, No. 5, pp. 713–722, November, 1973.  相似文献   

18.
Let X be a compactum and G an upper semi-continuous decomposition of X such that each element of G is the continuous image of an ordered compactum. If the quotient space X/G is the continuous image of an ordered compactum, under what conditions is X also the continuous image of an ordered compactum? Examples around the (non-metric) Hahn-Mazurkiewicz Theorem show that one must place severe conditions on G if one wishes to obtain positive results. We prove that the compactum X is the image of an ordered compactum when each gG has 0-dimensional boundary. We also consider the case when G has only countably many non-degenerate elements. These results extend earlier work of the first named author in a number of ways.  相似文献   

19.
As a counterpart to best approximation in normed linear spaces, best coapproximation was introduced by Franchetti and Furi. In this paper, we apply the above coapproximation, and obtain some results on the upper semi-continuity of cometric projection maps. Also we shall determine under what conditions coproximinality can be transmitted to and from quotient spaces.  相似文献   

20.
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