关于模糊数序列收敛性问题的研究

讨论了模糊数序列在EW-型积分度量下的收敛性问题.首先给出了模糊数序列关于EW-型积分度量、水平EW-型度量以及水平EW-型测度收敛的概念;其次,讨论了模糊数序列关于EW-型积分度量、下方图度量以及水平度量收敛之间的关系,证明了在一定条件下模糊数序列关于EW-型积分度量、下方图度量以及水平度量收敛的等价性.     

模糊数关于紧承下方图度量的线性性质

证明了紧承下方图度量不是平移不变的.对紧承下方图度量的代数运算的连续性进行了讨论.证明了关于紧承下方图度量,模糊数空间只能是嵌入到拓扑向量空间当中,但不嵌入赋范线性空间当中.并与关于上确界度量的结果进行了比较.最后,给出了一个紧承下方图度量的下界.     

关于模糊数空间的Skorokhod拓扑的注记

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.     

模糊数空间的紧化

通过表明模糊数空间上的下方图形度量拓扑与Fell拓扑一致,给出了带有下方图形度量的模糊数空间的一个自然的紧化.     

模糊数空间上的积分度量及其在模糊聚类中的应用

在本文中,首先利用区间数的EW-型度量探讨了模糊数空间上的积分度量问题,给出了模糊数空间上的一种新的积分度量-EW-型积分度量,并证明了其相关性质.其次,作为EW-型积分度量的应用,设计了对属性特征为三角模糊数的事物进行分类的模糊聚类算法.然后通过实例分析,说明了EW-型积分度量使模糊聚类算法实现的更简单易行,分类更加精细,合理有效等。     

模糊黎曼积分的拓广

给出了模糊黎曼积分的拓广定义,并证明了拓广的模糊黎曼积分在下方图度量和d1度量下可以通过有限个层次集逼近.     

模糊结构元诱导的两类加权模糊数度量

针对模糊数度量中不同隶属程度对度量的贡献程度应不同的客观事实,给出两类模糊数的结构元加权度量。首先,在区间[-1,1]上的同序标准单调有界函数类B[-1,1]上定义两类结构元加权度量dH、dp,分别讨论了这两类度量空间的完备性和可分性;其次,利用正则模糊结构元导出的模糊泛函,给出一种由B[-1,1]上度量诱导有界闭模糊数全体上的度量方法,进而给出由dH、dp诱导的两类模糊数结构元加权度量dNH、dNp,并分析了两类诱导的模糊数度量空间的完备性和可分性;最后,给出了dNH、dNp与传统方法定义的模糊数度量的区别与联系。     

基于模糊积分的一类图像度量

通过（S）型模糊积分和（G）型模糊积分定义一类新的图像度量,实验证明,在衡量图像失真度方面该图像度量比传统的图你度量（包括峰值信噪比PSNR））更合适于人类的视觉系统。     

关于模糊数空间的上确界度量化问题

讨论了模糊数空间的上确界度量化问题,指出了已有上确界度量,即一致Hausdorff度量的不足。利用区间数和模糊数的关系,给出了模糊数空间上的一种新的上确界度量,即EW-型上确界度量,并通过实例验证了其有效性和合理性。讨论了EW-型上确界度量的相关性质,并证明了EW-型上确界度量同样使模糊数空间成为完备的度量空间。     

模糊数的积分变换

使用模糊数的联合隶属函数定义了模糊数的积分变换和逆积分变换,证明了模糊数在积分变换后的模糊数与原模糊数有相同的支撑与核.另外讨论了在积分变换和逆积分变换下保持不变时积分中基函数满足的充要条件,最后给出积分变换的两个应用.     

非紧超凸度量空间中的Browder不动点定理及其对重合问题的应用

在非紧超凸度量空间中的非紧允许集上，建立了一个新的Browder不动点定理．作为应用，在非紧超凸度量空间中，研究了Ky Fan截口问题和相交问题，并新建了两个Ky Fan重合定理．     

Taming 3-manifolds using scalar curvature

In this paper we address the issue of uniformly positive scalar curvature on noncompact 3-manifolds. In particular we show that the Whitehead manifold lacks such a metric, and in fact that \mathbbR³{\mathbb{R}^3} is the only contractible noncompact 3-manifold with a metric of uniformly positive scalar curvature. We also describe contractible noncompact manifolds of higher dimension exhibiting this curvature phenomenon. Lastly we characterize all connected oriented 3-manifolds with finitely generated fundamental group allowing such a metric.     

The Yamabe Constant on Noncompact Manifolds

We prove several facts about the Yamabe constant of Riemannian metrics on general noncompact manifolds and about S. Kim’s closely related “Yamabe constant at infinity”. In particular, we show that the Yamabe constant depends continuously on the Riemannian metric with respect to the fine C ²-topology, and that the Yamabe constant at infinity is even locally constant with respect to this topology. We also discuss to what extent the Yamabe constant is continuous with respect to coarser topologies on the space of Riemannian metrics.     

Steepest Descent on Real Flag Manifolds

Real flag manifolds are the isotropy orbits of noncompact symmetricspaces G/K. Any such manifold M is acted on transitively bythe (noncompact) Lie group G, and it is embedded in euclideanspace as a taut submanifold. The aim of this paper is to showthat the gradient flow of any height function is a one-parametersubgroup of G, where the gradient is defined with respect toa suitable homogeneous metric s on M; this generalizes the Kählermetric on adjoint orbits (the so-called complex flag manifolds).2000 Mathematics Subject Classification 53C30, 53C35.     

On the quasidiagonality of Roe algebras

Let X be a noncompact discrete metric space with bounded geometry. Associated with X are two C*-algebras, the so-called uniform Roe algebra B*(X) and coarse Roe algebra C*(X), which arose from the index theory on noncompact complete Riemannian manifolds. In this paper, we describe the quasidiagonality of B*(X) and C*(X) in terms of coarse geometric invariants. Some necessary and suficient conditions are given, which involve the Fredholm index and coarse connectedness of metric spaces.     

非紧超凸度量空间中的一个新的不动点定理及其对截口问题和相交问题的应用

In this paper, a new Browder fixed point theorem is established in the noncompact sub-admissible subsets of noncompact hyperconvex metric spaces. As application, a Ky Fan section theorem and an intersection theorem are obtained.     

On Convergence to Infinity

 By a metric mode of convergence to infinity in a regular Hausdorff space X, we mean a sequence of closed subsets of X with and , and a sequence (or net) in X is convergent to infinity with respect to provided for each contains eventually. Modulo a natural equivalence relation, these correspond to one-point extensions of the space with a countable base at the ideal point, and in the metrizable setting, they correspond to metric boundedness structures for the space. In this article, we study the interplay between these objects and certain continuous functions that may determine the metric mode of convergence to infinity, called forcing functions. Falling out of our results is a simple proof that each noncompact metrizable space admits uncountably many distinct metric uniformities. (Received 2 March 1999)     

On Convergence to Infinity

 By a metric mode of convergence to infinity in a regular Hausdorff space X, we mean a sequence of closed subsets of X with and , and a sequence (or net) in X is convergent to infinity with respect to provided for each contains eventually. Modulo a natural equivalence relation, these correspond to one-point extensions of the space with a countable base at the ideal point, and in the metrizable setting, they correspond to metric boundedness structures for the space. In this article, we study the interplay between these objects and certain continuous functions that may determine the metric mode of convergence to infinity, called forcing functions. Falling out of our results is a simple proof that each noncompact metrizable space admits uncountably many distinct metric uniformities.     

Isotonicity of the Metric Projection and Complementarity Problems in Hilbert Spaces

In this paper, as the extension of the isotonicity of the metric projection, the isotonicity characterizations with respect to two arbitrary order relations induced by cones of the metric projection operator are studied in Hilbert spaces, when one cone is a subdual cone and some relations between the two orders hold. Moreover, if the metric projection is not isotone in the whole space, we prove that the metric projection is isotone in some domains in both Hilbert lattices and Hilbert quasi-lattices. By using the isotonicity characterizations with respect to two arbitrary order relations of the metric projection, some solvability and approximation theorems for the complementarity problems are obtained. Our results generalize and improve various recent results in the field of study.