共查询到20条相似文献,搜索用时 62 毫秒
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本文构造了紧连通流形上非退化扩散过程的一些耦合,并使用随机分析的方法证明这些耦合是成功的,进一步地,耦合时间一阶矩有限。最后,我们使用耦合方法研究了扩散过程依全变差范数的收敛速度。 相似文献
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王颖 《数学年刊A辑(中文版)》1999,(2)
本文使用耦合方法,通过对耦合时间的矩的估计得到紧流形上扩散过程依全变差范数指数式收敛的结果;并利用非零第一特征值与特征函数,给出了另外两个估计. 相似文献
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非紧L-凸度量空间中的一般拟平衡问题组(英文) 总被引:1,自引:0,他引:1
本文建立了非紧完备L-凸度量空间中新的不动点定理.作为应用,获得了非紧完备L-凸度量空间中的一般拟平衡问题组和拟平衡问题组的平衡存在定理. 相似文献
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《数学的实践与认识》2017,(16)
讨论了在无穷区间上一类分数阶耦合系统边值问题解的存在性的问题.通过建立相应的相对紧的判定准则,构造相应的全连续算子,借助不动点理论及Leray-Schauder非线性抉择,得到解的存在性. 相似文献
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李林锐 《数学的实践与认识》2018,(3)
研究了一类新的修正的Leray-α磁流体动力学方程组的初始值问题,利用方程的耦合结构,通过采用能量方法、紧性方法、Sobolev嵌入法等,证明了模型解在二维情形下解的整体存在性. 相似文献
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格值半连续映射和L-不分明Hausdorff良紧空间 总被引:5,自引:0,他引:5
彭育威 《数学年刊A辑(中文版)》1990,(6)
本文给出了格值映射上(下)半连续性的一组代数刻划,证明了Hausdorff良紧空间的子集是良紧集当且仅当它是底空间上的上半连续映射,进而给出了Hausdorff良紧空间的拓扑结构。应用这一结果,改进了[4]关于T_2~*弱诱导紧化方面的基本结果,使之适合于更一般的Hausdorff紧化;本文还讨论了良紧空间上的连续映射的若干性质。 相似文献
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遗传σ-亚紧空间及其乘积性质 总被引:8,自引:0,他引:8
本文首先获得遗传σ 亚紧空间的一组等价刻划.然后,利用这组刻划得到了这类空间的两个Tychonof乘积定理以及关于σ 积的定理.最后指出:本文得到的遗传σ 亚紧空间的两个Tychonof乘积定理在σ 亚紧的情形下不成立. 相似文献
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We extend known results concerning the centre of spaces of regular (resp. weakly compact or compact) operators between two Banach lattices to the setting of L-weakly compact and M-weakly compact operators. We also show that the L-weakly compact, M-weakly compact, and compact operators lying in the centre of a Banach lattice coincide. 相似文献
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Inthispaper,allspacesareregularandT1,andallmappingsarecontinuousandonto .Readersmayreferto [1 ]forunstateddefinitions. Quiterecently ,somecharacterizationsforcertainL imagesofparacompactlocallycompactspaceshavebeenobtainedin [2 ] .Similarly ,wecanestablishthech… 相似文献
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双随机矩阵有许多重要的应用, 紧图族可以看作是组合矩阵论中关于双随机矩阵的著名的Birkhoff定理的拓广,具有重要的研究价值. 确定一个图是否紧图是个困难的问题,目前已知的紧图族尚且不多.给出了两个重要结果:任意紧图与任意多个孤立点的不交并是紧图;任意紧图的每一个顶点上各增加一条悬挂边的图是紧图. 利用这两个结果,从已知紧图可构造出无穷多个紧图族. 相似文献
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Matjaž Konvalinka 《Integral Equations and Operator Theory》2005,52(2):271-284
An operator on a complex Banach space is polynomially compact if a non-zero polynomial of the operator is compact, and power compact if a power of the operator is compact. Theorems on triangularizability of algebras (resp. semigroups) of compact operators are shown to be valid also for algebras (resp. semigroups) of polynomially (resp. power) compact operators, provided that pairs of operators have compact commutators. 相似文献
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I. A. Pyatyshev 《Mathematical Notes》2007,82(5-6):653-659
In the paper, the problem of preserving the property of approximative compactness under diverse operations is considered. In an arbitrary uniformly convex separable space, we construct an example of two approximatively compact sets whose intersection is not approximatively compact. An example of two linear approximatively compact sets for which the closure of their algebraic sum is not approximatively compact is constructed. In an arbitrary Banach space, we construct two nonlinear approximatively compact sets whose algebraic sum is closed but not approximatively compact. We also prove that any uniformly closed Banach space contains an approximatively compact cavity. 相似文献
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Oleg Gutik 《Semigroup Forum》2000,60(2):243-252
A locally compact commutative band with open principal ideals is a zero-dimensional scattered space. Cardinal invariants of locally compact and compact commutative bands with open principal ideals is investigated. A base of the topology of a compact commutative band with open principal ideals is determined and the structure of such compact semilattices in which every principal lower set is a chain is described. Every first countable compact inverse semigroup with open right (left, two-sided) principal ideals is metrizable 相似文献
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Ofelia T. Alas Vladimir V. Tkachuk Richard G. Wilson 《Central European Journal of Mathematics》2014,12(3):500-509
We study maximal pseudocompact spaces calling them also MP-spaces. We show that the product of a maximal pseudocompact space and a countable compact space is maximal pseudocompact. If X is hereditarily maximal pseudocompact then X × Y is hereditarily maximal pseudocompact for any first countable compact space Y. It turns out that hereditary maximal pseudocompactness coincides with the Preiss-Simon property in countably compact spaces. In compact spaces, hereditary MP-property is invariant under continuous images while this is not true for the class of countably compact spaces. We prove that every Fréchet-Urysohn compact space is homeomorphic to a retract of a compact MP-space. We also give a ZFC example of a Fréchet-Urysohn compact space which is not maximal pseudocompact. Therefore maximal pseudocompactness is not preserved by continuous images in the class of compact spaces. 相似文献
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Artur Hideyuki Tomita 《Topology and its Applications》2005,153(1):107-122
We show in ZFC that the existence of a countably compact Abelian group without non-trivial convergent sequences implies the existence of a countably compact group whose square is not countably compact.This improves a result obtained by van Douwen in 1980: the existence of a countably compact Boolean group without non-trivial convergent sequences implies the existence of two countably compact groups whose product is not countably compact in ZFC.Hart and van Mill showed in 1991 the existence of a countably compact group whose square is not countably compact under Martin's Axiom for countable posets. We show that the existence of such an example does not depend on some form of Martin's Axiom. 相似文献
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