概率度量空间中若干新的不动点定理*

本文提出了Z-M-PN空间的概念,在概率度量空间中我们得到了若干新的不动点定理。同时,一些着名的不动点定理在概率度量空间中得到了推广,诸如:Schauder不动点定理、郭大钧不动点定理和Petryshyn不动点定理被推广到M-PN空间;Altman不动点定理被推广到Z-M-PN空间。     

Leray-Schauder不动点定理的一个新证明

给出Leray-Schauder不动点定理的一个新证明.我们首先给出集值映射的焊接引理,利用集值映射的焊接引理和Kakutani不动点定理证明Leray-Schauder不动点定理,并证明Leray-Schauder不动点定理与Brouwer不动点定理等价.     

一个一般的多值随机算子的随机不动点定理

近年来,由于理论和应用上的需要,随机不动点定理的研究获得了很大进展.许多重要的不动点定理的随机类比已相继得到证明。本文的定理2.1是一个一般的随机不动点定理,它推广了重要的 Chuong 的结果.利用这个定理,结合非随机不动点定理立即可以得到许多非随机不动点定理的随机类比.例如,[1,2,4,6]中的结果都是本定理的特例。     

Menger概率度量空间中Caristi型混合不动点定理

本文在Menger概率度量空间中引进Caristi型混合不动点概念,得到两个混合不动点定理和两个集值映象序列的公共混合不动点定理,我们的定理改进和推广了Caristi不动点定理及相关的近期重要结果.     

度量空间和锥度量空间中的若干不动点定理

给出了度量空间和锥度量空间中的若干不动点定理.利用这些不动点定理,统一并推广了度量空间和锥度量空间中的若干经典的不动点定理.     

锥度量空间上混合型膨胀映射族的唯一公共不动点

引进了一类混合型膨胀映射族,并在锥度量空间上证明了此类映射族具有唯一公共不动点的定理,同时给出了相应的不动点定理,推广和改进了文献中关于第I膨胀映射的相应的公共不动点和不动点定理.     

Browder不动点定理的推广及应用

研究 Ｂｒｏｗｄｅｒ 不动点定理, 得到 Ｂｒｏｗｄｅｒ 不动点定理之一新的推广定理及其几种等价形式·　作为应用,研究了最近点和不动点的存在性问题·     

CARISTI型Fuzzy混合不动点定理

本文提出ｆｕｚｚｙ混合不动点的概念，给出两个ｆｕｚｙ混合不动点定理和两个ｆｕｚｙ映象序列的公共ｆｕｚｚｙ混合不动点定理．本文的结果改进和推广了Ｃａｒｉｓｔｉ不动点定理及其近期的重要推广     

实线性锥距离空间和不动点定理

给出了实线性锥距离空间的概念,其中锥距离取值到没有拓扑结构的实线性空间,并在实线性锥距离空间中建立了几个新的不动点定理.利用非线性标量化函数证明了这些不动点定理与距离空间中相应形式的不动点定理等价.我们的结果改进了锥距离空间中的一些现有不动点定理.     

2—距离空间中三个等价的不动点定理

自Gahler于1963年引入2-距离空间理论以来,国内外一些学者研究了该空间上的不动点定理,这方面的成果在[2]中作了系统的介绍。本文首先给出2-距离空间中一个压缩型映象的不动点定理,并由它导出另两个不动点定理。这两个定理分别是通常距离空间中D.W.Boyd and J.S.Wong不动点定理和J.Dugundji and A.Granas不动点定理的推广。最后,我们还证明上述三个不动点定理的等价性。     

New cone fixed point theorems for nonlinear multivalued maps with their applications

In this paper, we first establish some new types of fixed point theorems for nonlinear multivalued maps in cone metric spaces. From those results, we obtain new fixed point theorems for nonlinear multivalued maps in metric spaces and the generalizations of Mizoguchi–Takahashi’s fixed point theorem and Berinde–Berinde’s fixed point theorem. Some applications to the study of metric fixed point theory are given.     

Fixed point results on a metric space endowed with a finite number of graphs and applications

In this paper, we consider self-mappings defined on a metric space endowed with a finite number of graphs. Under certain conditions imposed on the graphs, we establish a new fixed point theorem for such mappings. The obtained result extends, generalizes and improves many existing contributions in the literature including standard fixed point theorems, fixed point theorems on a metric space endowed with a partial order and fixed point theorems for cyclic mappings.     

Approximation of common fixed points of a countable family of nonexpansive mappings in a Banach space

In this paper, to find a common fixed point of a family of nonexpansive mappings, we introduce a Halpern type iterative sequence. Then we prove that such a sequence converges strongly to a common fixed point of nonexpansive mappings. Moreover, we apply our result to the problem of finding a common fixed point of a countable family of nonexpansive mappings and the problem of finding a zero of an accretive operator.     

Investigation of positive solution to a coupled system of impulsive boundary value problems for nonlinear fractional order differential equations

In this article, we study a coupled system of impulsive boundary value problems for nonlinear fractional order differential equations. We obtain sufficient conditions for existence and uniqueness of positive solutions. We use the classical fixed point theorems such as Banach fixed point theorem and Krasnoselskii’s fixed point theorem for uniqueness and existence results. As in application, we provide an example to illustrate our main results.     

Distortion and stability of the fixed point property for non-expansive mappings

Let X be a Banach space. We say that X satisfies the fixed point property (weak fixed point property) if every non-expansive mapping defined from a convex closed bounded (convex weakly compact) subset of X into itself has a fixed point. We say that X satisfies the stable fixed point property (stable weak fixed point property) if the same is true for every equivalent norm which is close enough to the original one. Denote by P(X) the set formed by all equivalent norms with the topology of the uniform convergence on the unit ball of X. We prove that the subset of P(X) formed by the norms failing the fixed point property is dense in P(X) when X is a non-distortable space which fails the fixed point property. In particular, no renorming of ?₁ can satisfy the stable fixed point property. Furthermore, we show some examples of distortable spaces failing the weak fixed point property, which can be renormed to satisfy the stable weak fixed point property. As a consequence we prove that every separable Banach space can be renormed to satisfy the stable weak fixed point property.     

Fixed Point Theorems for Weakly Contractive Mappings in Ordered Metric Spaces with an Application

In this paper, we prove fixed point theorem for weakly contractive mappings using locally $T$-transitivity of binary relation and presenting an analogous version of Harjani and Sadarangani theorem involving more general relation theoretic metrical notions. Our fixed point results under universal relation reduces to Harjani and Sadarangani [Nonlinear Anal., 71 (2009), 3403–3410] fixed point theorems. In this way we also generalize some of the recent fixed point theorems for weak contraction in the existing literature.     

Applications of Michael's selection theorems to fixed point theory

Applying some of Ernest Michael's selection theorems, from recent fixed point theorems on u.s.c. multimaps, we deduce generalizations of the classical Bolzano theorem, several fixed point theorems on multimaps defined on almost convex sets, almost fixed point theorems, coincidence theorems, and collectively fixed point theorems. These results are related mainly to Michael maps, that is, l.s.c. multimaps having nonempty closed convex values.     

Fixed Point Theorems and a New System of Multivalued Generalized Order Complementarity Problems*

Some new fixed point and coupled fixed point theorems for multivalued increasing type mappings are obtained and a new system of multivalued generalized order complementarity problems is introduced in this paper. In terms of new fixed point and coupled fixed point theorems, we give some existance results of solutions for this new system of multivalued generalized order complementarity problems. The results presented in this paper extend and improve the corresponding results announced by Isac and Kostreva.