Regularity of Continuous Linear Operators on Banach Function Spaces

In this paper we present some characterizations of Banach function spaces on which every continuous linear operator is regular.     

Fixed Point Theory for 1-Set Weakly Contractive Operators in Banach Spaces

In this work, using an analogue of Sadovskii＇s fixed point result and several important inequalities we investigate and give new existence theorems for the nonlinear operator equation F（x） =μx, （μ≥1） for some weakly sequentially continuous, weakly condensing and weakly 1-set weakly contractive operators with different boundary conditions. Correspondingly, we can obtain some applicable fixed point theorems of Leray-Schauder, Altman and Furi-Pera types in the weak topology setting which generalize and improve the corresponding results of [3,15,16].     

A Reuniformization for Contractive Mappings in Uniform Spaces

Let X be a complete uniform HAUSDORFF space with a uniformity generated by a saturated family of pseudometrics ?? = {?_α(x, y): α ? A} and let T: X → X be a continuous mapping. The paper contains necessary and sufficient conditions for the existence of a new family of pseudometrics ??*={?*(x, y): α*?A*} generated the same topology such that T is contractive with respect to ??*.     

Hyperbolic Harmonic Functions: Weak Approach with Applications in Function Spaces

Harmonic functions with respect to the Poincare metric on the unit ball are called hyperbolic harmonic functions. We establish the weak formulation of hyperbolic harmonic functions and use it in the study of hyperbolic harmonic function spaces. In particular, we give the Carleson measure characterization for the whole spectrum of spaces, whose analytic counterparts include among else Bloch spaces, Bergman-spaces, Besov-spaces, and Q_p-spaces. The second author was supported by the Finnish Cultural Foundation.     

Minimal Extensions in Tensor Product Spaces

LetX,Ybe two separable Banach spaces and letVXandWYbe finite dimensional subspaces. Suppose thatVSX,WZYand letM (S, V),N (Z, W). We will prove that ifαis a reasonable, uniform crossnorm onXYthenλ_MN(V_αW,X_αY)=λ_M(V, X) λ_N(W, Y).Here for any Banach spaceX,VSXandM (S, V)

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Also some applications of the above mentioned result will be presented.     

无穷维空间中的Lyapunov函数方法和随机稳定性

在本文中,我们对Hilbert空间中随机发展方程的渐近稳定性问题的最新进展作一综述。     

On Spectral Synthesis for Contractive p-Norms and Besov Spaces

We prove that spectral synthesis is possible for a general function space F _p with a contractive p-norm, namely, any quasi-continuous function in F _p vanishing q.e. outside an open set G can be approximated in this norm by continuous functions in F _p with compact support in G. The result is applied to contractive Besov spaces over d-sets in R ^N and censored stable processes over N-sets.     

On Immediate Extensions of Ultrametric Spaces

The purpose of this paper is to define immediate extensions of ultrametric spaces with a totally ordered value set. It will be proved that an ultrametric space (X, d) with value set F is maximal if and only if it is pseudocomplete, i. e. any pseudoconvergent sequence of (X, d) has a pseudolimit in X. Every ultrametric space will be shown to possess a maximal immediate extension, but its uniqueness can only be obtained within the more specific class of essential extensions.     

On Strict Extensions of Nearness Spaces

Strict extensions of nearness spaces are constructed as spaces of round Cauchy filters. Morita's simple extension is identified as the strict extension generated by Morita-generated filters. Carlson's B-completeness is compared with Herrlich completeness and completeness of Morita T-uniformities. The three completeness concepts are shown to be equivalent in regular nearness spaces.     

Approach Theory in Merotopic, Cauchy and Convergence Spaces. II

We define the notions of approach-Cauchy structure and ultra approach-Cauchy structure. We study the categorical properties of ACHY and uACHY and show that in these schemes Cauchy spaces and extended pseudo-(ultra)metric spaces are regarded as entities of the same kind. Furthermore, we investigate the relation with convergence-approach spaces and obtain a relationship similar to that of CONV and CHY.     

Interval Extensions of Orders and Temporal Approximation Spaces

Siberian Mathematical Journal - Studying the algorithmic properties of interval extensions of dense linear orders, in particular, the complexity degrees (namely, the $ sSigma $ -degree)...     

Approach Theory in Merotopic, Cauchy and Convergence Spaces. I

We introduce the notions of approach-merotopic structure and approach-filter merotopic structure by means of a map assigning to a collection of sets 'smallness' of members and define categories AMER and AFIL containing MER and FIL as bireflectively and bicoreflectively embedded subcategories, respectively. We show that the category AMER is a topological construct and AFIL which is a supercategory of ps-MET as well is a cartesian closed topological category bicoreflectively embedded in AMER.     

Proximal Weakly Contractive and Proximal Nonexpansive Non-self-Mappings in Metric and Banach Spaces

In this work, we consider two classes of non-self-mappings, which are called proximal weakly contractive and proximal nonexpansive mappings, and study the existence of solutions of a minimization problem. Existence results of best proximity points for these two classes of non-self-mappings in metric and Banach spaces are also obtained.     

L—Fuzzy拓扑空间的正则

本文给出一种在Ｌ－Ｆｕｚｚｙ拓扑空间中的正则，记作Ｎ－正则，且证明了它不仅强于文献「１」中所提出的正则，而且还具有一系列好的性质，最后我们给出一个定理说明了Ｎ－正则与良紧性之间的关系。     

半序概率度量空间中压缩算子的不动点定理

半序方法是研究非线性算子方程问题的主要方法之一.在概率度量空间中引入半序,并且利用半序方法研究了非线性算子的不动点问题,推广了度量空间中序压缩算子的不动点定理,获得若干新的结果.