映像组公共不动点的存在性与稳定性

本文建立乘积距离空间中集值与单值映像组的非线性压缩型公共不动点定理以及集值映像组公共不动点集的稳定性定理.     

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。     

b-距离空间中有限个等式约束下的耦合不动点问题

本文研究了b-距离空间中有限个等式约束下的耦合不动点问题.利用数学归纳法,获得了b-距离空间中一类有限个等式约束下的非线性压缩耦合不动点结果,将已有的Banach空间中的结果推广到b-距离空间中.特别地,我们结果中的压缩条件与空间系数无关.作为应用,得到了对称等式约束下的不动点定理,公共耦合不动点定理以及b-距离空间中非线性压缩不动点定理.这些结果可以推出许多已有结果,甚至将一些结果中的部分条件完全去掉.     

偏序2-距离空间中压缩型映象的公共耦合不动点定理

在偏序2-距离空间中,研究了一类压缩型映象不动点的存在性和唯一性问题.利用映象对的ω-相容性条件,获得了此类映象的一个新的耦合重合点和耦合公共不动点定理.所得结果是度量空间中某些经典结果在偏序2-距离空间的进一步推广和发展.     

模糊距离空间中几类非线性压缩不动点定理

在Kaleva-Seikkala型模糊距离空间中建立了Boyd-Wong型和Alber-Guerre Delabriere型非线性压缩不动点定理.这些结果补充了Xiao等人的几个结果.作为应用,获得了通常距离 空间和Menger概率距离空间中的几个非线性不动点定理.     

实线性锥距离空间中带有锥W-距离的不动点定理

在实线性锥距离空间中给出锥、W-距离的概念及一些性质．由此在实线性锥距离空间中建立了压缩型和扩张型两类不动点定理,其中压缩条件和扩张条件中均含有锥W-距离．     

偏距离空间上四个映射的公共不动点的存在性与唯一性

该文证明了偏距离空间上满足广义非线性压缩型的四个映射的公共不动点定理.最后,举例说明了该文压缩条件确实改进了目前一些文献中压缩条件.     

Lipschitz拟伪压缩映像族的收缩投影算法

在Hilbert空间中设计了一种关于Lipschitz拟伪压缩映像族的收缩投影算法,并利用所提出的算法证明了Lipschitz拟伪压缩映像族的公共不动点的强收敛定理,所得结果改进和推广了一些最新文献的相关结果.     

Banach空间中一类广义非扩张映像族公共不动点问题研究

1引言Banach空间中非扩张映像的不动点问题,由于其在变分不等式、优化及参数估计问题、反问题、图像恢复和信号处理等领域中的广泛应用[3,10,13-14],具有相当重要的理论意义和应用价值,一直是诸多学者的关注重点.不动点问题研究,包括不动点的存在判别、不动点集性质研究、不动点构造以及不动点理论在相关领域的应用等.     

WF-模糊度量空间中的不动点理论

在WF-模糊度量空间中建立压缩型和局部压缩型映射的不动点理论，推广一些重要的不动点定理。     

On Fuzzy Metric Space

In this paper we prove a common fixed point theorem for three mappings in fuzzy metric space and then extend this result to fuzzy 2 and 3-metric spaces. Our theorem is an extension of result of Fisher [12], to fuzzy metric spaces.AMS Subject Classification (1990): 47H10, 54H25     

Common fixed point theorems for three maps in discontinuous Gb metric spaces

In [Aghajani A, Abbas M, Roshan JR. Common fixed point of generalized weak contractive mappings in partially ordered G_b-metric spaces. Filomat, 2013, in press], using the concepts of G-metric and b-metric Aghajani et al. defined a new type of metric which is called generalized b-metric or G_b-metric. In this paper, we prove a common fixed point theorem for three mappings in G_b-metric space which is not continuous. An example is presented to verify the effectiveness and applicability of our main result.     

A result of suzuki type in partial G-metric spaces

Recently, Suzuki [T. Suzuki, A generalized Banach contraction principle that characterizes metric completeness, Proc. Amer. Math. Soc. 136 (2008), 1861-1869] proved a fixed point theorem that is a generalization of the Banach contraction principle and characterizes the metric completeness. Paesano and Vetro [D. Paesano and P. Vetro, Suzuki's type characterizations of completeness for partial metric spaces and fixed points for partially ordered metric spaces, Topology Appl., 159 (2012), 911-920] proved an analogous fixed point result for a self-mapping on a partial metric space that characterizes the partial metric 0-completeness. In this article, we introduce the notion of partial G-metric spaces and prove a result of Suzuki type in the setting of partial G-metric spaces. We deduce also a result of common fixed point.     

Unique common fixed point of a family of self-maps with same type contractive condition in 2-metric space

In this paper, we prove that a family of self-maps {Ti,j}i,j∈N in 2-metric space has a unique common fixed point if (i) {Ti,j}i,j∈N satisfies the same type contractive condition for each j ∈ N; (ii) Tm,μ· Tn,ν = Tn,ν· Tm,μ for all m,n,μ,ν∈ N with μ = ν. Our main result generalizes and improves many known unique common fixed point theorems in 2-metric spaces.     

完备bv(s)-度量空间中广义ψ-Geraghty压缩的不动点定理

本文介绍了bv(s)-度量空间中广义ψ-Geraghty压缩的概念.利用不动点理论的方法获得了在完备bv(s)-度量空间中关于此压缩映射的不动点定理并且得到一些推论.此外,给出了一个支持本文主要结果的例子.     

Cone metric spaces and fixed point theorems in diametrically contractive mappings

In this paper, some topological concepts and definitions are generalized to cone metric spaces. It is proved that every cone metric space is first countable topological space and that sequentially compact subsets axe compact. Also, we define diametrically contractive mappings and asymptotically diametrically contractive mappings on cone metric spaces to obtain some fixed point theorems by assuming that our cone is strongly minihedral.     

Fixed point results on metric-type spaces

In this paper we obtain fixed point and common fixed point theorems for self-mappings defined on a metric-type space, an ordered metric-type space or a normal cone metric space. Moreover, some examples and an application to integral equations are given to illustrate the usability of the obtained results.     

FIXED POINT RESULTS ON METRIC-TYPE SPACES

In this paper we obtain fixed point and common fixed point theorems for self- mappings defined on a metric-type space, an ordered metric-type space or a normal cone metric space. Moreover, some examples and an application to integral equations are given to illustrate the usability of the obtained results.     

COMMON FIXED POINT THEOREMS FOR THREE MAPS IN DISCONTINUOUS Gb-METRIC SPACES

In [Aghajani A, Abbas M, Roshan JR. Common fixed point of generalized weak contractive mappings in partially ordered Gb-metric spaces. Filomat, 2013, in press], using the concepts of G-metric and b-metric Aghajani et al. defined a new type of metric which is called generalized b-metric or Gb-metric. In this paper, we prove a common fixed point theorem for three mappings in Gb-metric space which is not continuous. An example is presented to verify the effectiveness and applicability of our main result.     

On Kirk's asymptotic contractions

Recently Kirk introduced the notion of asymptotic contractions on a metric space and using ultrapower techniques he obtained an asymptotic version of the Boyd-Wong fixed point theorem. In this paper we extend this result and moreover, we give a constructive proof of it. Furthermore, we obtain a complete characterization of asymptotic contractions on a compact metric space. As a by-product we establish a separation theorem for upper semicontinuous functions satisfying some limit condition.