共查询到20条相似文献,搜索用时 78 毫秒
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刘来山 《高校应用数学学报(A辑)》2012,27(3)
给出一个弱拟第一可数空间成为弱第一可数空间的充要条件,证明了空间是弱第一可数空间当且仅当它是具有序列点Gδ性质的弱拟第一可数空间且不含Sw的闭拷贝.同时还证明了每一弱第一可数空间(弱拟第一可数空间)都是某个第一可数空间的商二到一映像(商可数到一映像),作为应用,部分回答了林寿(2007)的一个问题. 相似文献
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本文利用msss-映射,建立了具有σ-局部可数cs-网的空间和具有σ-局部可数弱基的空间与度量空间的关系,这是对Alexandroff的部分的肯定回答。 相似文献
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本文证明了:(1)T1完全的弱δθ-加细空间是遗传性不可约空间,肯定地回答了作者前论文《关于不可约空间》中的问题3;(2)闭、可数紧映射及、可数紧映射均保持点可数基。由后者可得Arhangel’skii的MOBI类的每一空间都是不可约空间,肯定地回答了上述论文中的问题8。 相似文献
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高智民 《数学物理学报(A辑)》2005,25(4):516-521
函数刻画广义度量空间,最早可追溯至Heath和Hodel的工作. 近些年来,Nagat a和一些拓扑学者利用g函数系统地研究了度量化问题. 该文引入弱基g函数的概念,利用它给出拓扑空间度量化的一些等价刻画, 推广了前人的相关工作. 证明了拓扑空间X可以度量化,当且仅当X有弱基g函数满足条件(1)和(7). 相似文献
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某些局部凸空间上相对弱紧集,相对弱列紧集,相对弱可数紧集的关系 总被引:3,自引:0,他引:3
对可分离的局部凸空间(X,τ),本文建立了相应的局部凸空间(Qx,Tx),利用它证明了当(X,τ)满足某些条件时(赋范空间满足这些条件),EX相对弱紧E相对弱列紧E相对弱可数紧,从而推广了Eberlein等人的工作,证明了在空间D(R ̄n),(R ̄n)和D_(LP),1<p<∞上前述三种弱紧性等价. 相似文献
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沈荣鑫 《高校应用数学学报(A辑)》2010,25(2)
讨论了拟第一可数空间和弱拟第一可数空间的遗传性和可积性,给出了一些反例来说明这两类空间在某些拓扑运算下的不封闭性,同时研究了它们具有遗传性和可积性的充要条件. 相似文献
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本文利用τ弱仿紧空间的概念证明了一种τ选择的存在性。作为选择理论的应用,我们说明了具有可数序基的τ弱仿紧空间存在点τ的可数序基。 相似文献
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Simeon Reich 《Optimization》2019,68(1):51-63
ABSTRACTWe study the random weak ergodic property of infinite products of mappings acting on complete metric spaces. Our results describe an aspect of the asymptotic behaviour of random infinite products of such mappings. More precisely, we show that in appropriate spaces of sequences of operators there exists a subset, which is a countable intersection of open and everywhere dense sets, such that each sequence belonging to this subset has the random weak ergodic property. Then we show that several known results in the literature can be deduced from our general result. 相似文献
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In this paper, by using Mann's iteration process we will establish several weak convergence theorems for approximating a fixed point of k-strictly pseudocontractive mappings with respect to p in p-uniformly convex Banach spaces. Our results answer partially the open question proposed by Marino and Xu, and extend Reich's theorem from nonexpansive mappings to k-strict pseudocontractive mappings. 相似文献
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Shilong Wei & Weiping Guo 《数学研究》2015,48(3):256-264
The purpose of this paper is to prove some weak convergence theorems for
mixed type asymptotically nonexpansive mappings with mean errors in uniformly
convex Banach spaces. The results presented in this paper extend the corresponding
results in the references. 相似文献
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In this paper,we introduce two new iterative algorithms for finding a common element of the set of solutions of a general equilibrium problem and the set of solutions of the variational inequality for an inverse-strongly monotone operator and the set of common fixed points of two infinite families of relatively nonexpansive mappings or the set of common fixed points of an infinite family of relatively quasi-nonexpansive mappings in Banach spaces.Then we study the weak convergence of the two iterative sequences.Our results improve and extend the results announced by many others. 相似文献
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Summary The paper reveals that ultrabarrelled spaces (respectively barrelled spaces) can be characterized by means of the density
of the so-called weak singularities of families consisting of continuous convex mappings that are defined on an open absolutely
convex set and take values in a locally full ordered topological linear space (respectively locally full ordered locally convex
space). The idea to establish such characterizations arose from the observation that, in virtue of well-known results, the
density of the singularities of families of continuous linear mappings allows to characterize both the ultrabarrelled spaces
and the barrelled spaces. 相似文献
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In this paper,spaces with a locally countable sn-network are discussed.It is shown that a space with a locally countable sn-network iff it is an snf-countable space with a locally countable k-network.As its application,almost-open and closed mappings(or finite-to-one and closed mapping) preserve locally countable sn-networks,and a perfect preimage theorem on spaces with a locally countable sn-network is established. 相似文献
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在自反Banach空间中,引入可数族弱Bregman相对非扩张映像概念,构造了两种迭代算法求解可数族弱Bregman相对非扩张映像的公共不动点.在适当条件下,证明了两种迭代算法产生的序列的强收敛性. 相似文献
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弱相对非扩张映像不动点单调CQ算法与应用 总被引:2,自引:1,他引:1
Kamimura和Takahashi$^{[7]}$证明了相对非扩张映像CQ迭代算法的强收敛定理.该文构造了单调CQ算法, 用来逼近弱相对非扩张映像不动点, 证明了强收敛定理. 并将结果应用于逼近Banach空间极大单调算子的零点. 单调CQ算法比目前的CQ算法收敛速度快. 另外, 为证明弱相对非扩张映像不动点强收敛定理,该文运用了新的Cauchy列证明方法, 而不用Kadec-Klee性质, 该文结果改进了S.Matsushita 和 W.Takahashi及其它人的结果. 相似文献