共查询到19条相似文献,搜索用时 46 毫秒
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本文给王国俊先生发现的良紧性定义了一个分明拓扑模型,利用此模型较为简洁地证明了关于良紧性的吉洪诺夫定理。然后,仿照良紧性的定义方式定义了J——紧性。最后,利用彭育威先生对良紧性作出的几何刻划证明了良紧性与一般的J——紧性之间的一个重要关系。总之,本文的结果对认识模糊拓扑与分明拓扑之间的联系有一定的意义。 相似文献
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Fuzzy序列紧性,可数Fuzzy紧性和Fuzzy列紧性 总被引:3,自引:1,他引:2
本文引进了Fuzzy序列紧性、可数Fuzzy紧性和Fuzzy列紧性,它们是一般拓扑学中相应概念的“良扩张”(R. Lowen意义下),文中讨论了这些fts的主要性质,以及它们之间的联系。 相似文献
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本文在L-fuzzy拓扑空间中,针对L-fuzzy子集定义子Mr-复盖及具有有限Mr交性质的闭集族等概念,并以此刻画了近良紧集的一组特性,证明了近良紧的对正则闭集遗传以及是“L-good extension”等结论。 相似文献
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设X是拓扑空间,CL(X)表示X的所有非空闭子集的族,本文得到了下述结果:在CL(X)上的Fell-拓扑是伪肾的当且仅当X是feebly-紧或者非局部紧或者非σ-紧,由此得到了对于伪紧性不是闭遗传的两类新的拓扑空间。 相似文献
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L-smooth拓扑空间中的几类弱映射及其关系 总被引:10,自引:0,他引:10
给出L-smooth不定开映射和L-smooth不定闭映射以及L-smooth不定映射以及其他几种相关映射的概念.讨论它们之间的一些关系,证明与这些概念相等价的命题。 相似文献
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在不分明化拓扑空间中,从正则开集出发引入了近似紧性和几乎紧性的概念,并且给出了它们的一些性质.这些概念的结合有助于我们对不分明化拓扑的研究。 相似文献
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首先考察模糊数空间中Skorokhod度量与紧承下方图度量之间的关系,然后说明了文献[4]中的关于Skorokhod拓扑紧致性的例子是错误的并给出了正确的例子. 相似文献
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§ 1.Introduction For a compact Hausdoff space X,Bell and van Mill[1 ] defined the compactness numbercompn(X) of X in the following manner: compn(X)≤ k if X has an open subbase(that is a usual subbase;dually,we can de-fine a closed subbase) Usuch that each cover of X by elements of Uhas a subcover of at most k members; compn(X) =k if compn(X)≤ k holds but compn(X)≤ k-1 does not hold; compn(X) =ω if compn(X) \≤k for all k∈ ω.In particular,X is called supercompact if compn(… 相似文献
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Pair of weights u, v is characterized so that the Hardy-Steklov operator is compact between weighted Lebesgue spaces Lp(u) and Lq(v), where 1<p,q<∞, a,b are certain increasing functions and f?0. The compactness of the conjugate operator is also studied. 相似文献
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For a sequence of blow up solutions of the Yamabe equation on non-locally conformally flat compact Riemannian manifolds of dimension 10 or 11, we establish sharp estimates on its asymptotic profile near blow up points as well as sharp decay estimates of the Weyl tensor and its covariant derivatives at blow up points. If the Positive Mass Theorem held in dimensions 10 and 11, these estimates would imply the compactness of the set of solutions of the Yamabe equation on such manifolds. 相似文献
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Gunther Jäger 《Fuzzy Sets and Systems》1997,90(3):737-348
Lowen and Lowen [Applications of category theory to fuzzy subsets (Kluwer, 1992) p. 153] and Lowen et al. [Fuzzy Sets and Systems 40 (1991) 347] recently introduced the category FCS of fuzzy convergence spaces, a topological quasitopos which is a supercategory of FTS, the category of fuzzy topological spaces. In this paper, compactness in FCS is examined. Doing so we found that to define compactness as an absolute property we had to generalize the definition of fuzzy convergence space to fuzzy subsets. All basic theorems are proved including the Tychonoff product theorem. Based on the theory developed here, in a following publication, a Richardson compactification for fuzzy convergence spaces will be given. 相似文献