共查询到19条相似文献,搜索用时 78 毫秒
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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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本文研究了Sierpinski gasket上Brownian运动的水平集与紧集之交的Hausdorff维数,证明了:若E为[0,∝)中紧集,x∈G,dimE>ds/2。 相似文献
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L—fuzzy拓扑空间中的层仿紧集 总被引:5,自引:0,他引:5
首先,在L-fuzzy拓扑空间中引入了强α-局部有限族,并以此定义了比Ⅱ型强仿紧性更为广泛的层仿紧性,且讨论了层仿紧集的基本性质。其次,针对L-fuzzy子集引入了层Hausdorff分离性,研究了它的基本特征。最后,讨论了弱诱导包含式正则空间中层仿紧集的特征。 相似文献
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给出了一般的L-不分明拓扑空间的Alexandorff紧化,并且对弱诱导空间证明了该紧化是弱诱导紧化类中唯一最小的紧化。 相似文献
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为了进一步研究Banach格上算子的性质,受b-序有界集和Dunford-Pettis集定义的启发,给出了b-Dunford-Pettis算子的定义,研究了该算子与b-AM-紧算子(Dunford-Pettis全连续算子,弱极限算子,序Dunford-Pettis算子)间的关系;利用b-Dunford-Pettis算子与Dunford-Pettis算子的共轭关系,证明了b-Dunford-Pettis算子满足控制性. 相似文献
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设X是一般状态空间E上的跳过程(见定义1),刘禄勤在弱对偶的框架上,对E上关于X的暂留集定义了容度,本文将其扩张到E的所有子集上成为一个以紧集类为铺的Choguest容度 相似文献
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Retakh条件(M0)与弱(序列式)紧正则性 总被引:1,自引:0,他引:1
本文研究了弱(序列式)紧正则诱导极限与凸弱(序列式)紧正则诱导极限.满足Retakh条件(Mo)的(LF)-空间必为凸弱(序列式)紧正则的,但未必为弱(序列式)紧正则的.对于弱序列式完备Frechet空间的可数诱导极限,Retakh条件(Mo)蕴涵弱(序列式)紧正则性.特别地,对于Kothe(LF)-序列空间Ep(1≤p<∞),Retakh条件(Mo)等价于弱(序列式)紧正则性.对于这类空间,利用Vogt的有关结论,给出了弱(序列式)紧正则性的特征. 相似文献
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《Journal of Functional Analysis》2023,284(10):109889
We introduce a measure of super weak noncompactness Γ defined for bounded subsets and bounded linear operators in Banach spaces that allows to state and prove a characterization of the Banach spaces which are subspaces of a Hilbert-generated space. The use of super weak compactness and Γ casts light on the structure of these Banach spaces and complements the work of Argyros, Fabian, Farmaki, Godefroy, Hájek, Montesinos, Troyanski and Zizler on this subject. A particular kind of relatively super weakly compact sets, namely uniformly weakly null sets, plays an important role and exhibits connections with Banach-Saks type properties. 相似文献
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Erhan Çalişkan 《Czechoslovak Mathematical Journal》2007,57(2):763-776
We show that a Banach space E has the weakly compact approximation property if and only if each continuous Banach-valued polynomial on E can be uniformly approximated on compact sets by homogeneous polynomials which are members of the ideal of homogeneous polynomials
generated by weakly compact linear operators. An analogous result is established also for the compact approximation property. 相似文献
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Alex Hellsten 《Archive for Mathematical Logic》2006,45(6):705-714
We extract some properties of Mahlo’s operation and show that some other very natural operations share these properties. The weakly compact sets form a similar hierarchy as the stationary sets. The height of this hierarchy is a large cardinal property connected to saturation properties of the weakly compact ideal. 相似文献
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Reduction of quasidifferentials and minimal representations 总被引:1,自引:0,他引:1
Some criterias for the non-minimality of pairs of compact convex sets of a real locally convex topological vector space are proved, based on a reduction technique via cutting planes and excision of compact convex subsets. Following an example of J. Grzybowski, we construct a class of equivalent minimal pairs of compact convex sets which are not connected by translations.Corresponding author. 相似文献
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称局部凸空间(E,(?)0)为WCM空间若对于任何弱于(?)0的局部凸拓扑(?),(E,(?))与(E,(?)0)具相同的弱紧圆凸集.本文研究了WCM空间的存在性及其与其他类型局部凸空间之间的关系,还给出了WCM空间的一种映照特征. 相似文献
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本文首先对紧致的度量拓扑空间证明了有限点集的费马点是存在的,其次,运用度量几何的经典方法考察了度量空间(包括双曲空间和Banach空间)中有限点集的费马点的唯一性,此外,还对n维欧氏空间E^n中有限点集的费马作了进一步研究。 相似文献
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Series of fuzzy sets with weakly closed, weakly compact or compact α-levels are considered. The basic space is Banach space. The subject of this paper is investigation of infinite addition of fuzzy sets and condition when the sum of α-levels is equal to the α-level of the sum. The results in this paper complement and complete some previous results proved by the same authors in Stojaković and Stojaković [Addition and series of fuzzy sets, Fuzzy Sets and Systems 83 (1996) 341–346] for the series with compact α-levels. 相似文献
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Jing Hui QIU 《数学学报(英文版)》2007,23(12):2295-2302
In the framework of topological vector spaces, we give a characterization of strong Minkowski separation, introduced by Cheng, et al., in terms of convex body separation. From this, several results on strong Minkowski separation are deduced. Using the results, we prove a drop theorem involving weakly countably compact sets in locally convex spaces. Moreover, we introduce the notion of the co-drop property and show that every weakly countably compact set has the co-drop property. If the underlying locally convex space is quasi-complete, then a bounded weakly closed set has the co-drop property if and only if it is weakly countably compact. 相似文献
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Pablo Galindo 《Proceedings of the American Mathematical Society》1996,124(5):1481-1488
We prove that scalar-valued polynomials are weakly continuous on limited sets and that, as in the case of linear mappings, every -valued polynomial maps limited sets into relatively compact ones. We also show that a scalar-valued polynomial whose derivative is limited is weakly sequentially continuous.