关于压缩型映象的一个未解决的问题

设(X,d)是一完备的度量空间,设T是X的自映象.按照Rhoades,我们称满足下面的条件(Ⅰ)的映象T为第(25)类的压缩型映象: 第(25)类压缩型映象是压缩型映象类中重要而广泛的一类映象,它包含     

Fuzzy拓扑空间中的紧性(Ⅰ)——定义和特征(英文)

本文在引入了一复盖的概念之后,定义了(?)一紧性,得出了关于闭集中心族,F-网与F-滤子的(?)-紧性的特微,以及A1exander子基定理。并进一步定义了S-紧,L-紧,I-紧和F-紧性,讨论了这些概念之间的关系。设A,B∈I~Y为X中的Fuzzy集,我们称有序对〈A,B〉为X中的一个(?)一集。定义1 设(X,F)是一个Fuzzy拓扑空间,〈A,B〉为X中的一个(?)一开集,P∈P_*(X)。如果〈A,B〉是P的邻域,则我们说〈A,B〉覆盖P。一个开(?)一集族(?)={〈A_λ,B_λ〉:λ∈Λ}称为X的一个(?)-覆盖,当且仅当对于任一P∈IP_*(X),存在λ∈Λ,使〈A_λ,B_λ>覆盖P。定义2 Fuzzy拓扑空间(X,F)称为(?)-紧的,当且仅当每个(?)覆盖都有有限子(?)-覆盖。定理1 Fuzzy拓扑空间(X,F)是(?)-紧的,当且仅当每个闭(?)-集构成的有限中心族都是中心族。定理2 Fuzzy拓扑空间(X,F)是(?)-紧的,当且仅当X中的每个F-网或者(?)-滤子都有聚点。定理5 设S为Fuzzy拓扑空间(X,F)的一个子基,若每个(?)覆盖(?)={〈A_λ,B_λ〉:A_λ,B_λ∈S,λ∈Λ}都有有限子覆盖,则(X,F)是(?)-紧的。     

不动点理论的新发展(Ⅰ)

§1 引言 设(X,d)是一完备度量空间,设T是映X到X的映象。我们称x∈X为T的不动点,如果Tx=x。设了是映X到2~x(X的一切子集的集合族)的多值映象,我们称x∈X为T的不动点,如果x∈Tx。 易知一算子T的不动点集,与特征值问题     

一类型集值积分方程解的存在性

本文设(X,)是Banach空间,L(X)是X的非空有界闭子集族,H是导出的Hausdorff度量.此外,∧是一指标集.作为准备,我们有以下Chen和Shin的结果对集值映象情形的推广: 引理设T_λ:X→L(X)(λ∈∧),使得这里函数φ满足(φ):φ:[0,∞)→[0,∞)不减,φ(t)0),且(?)α≥0,存在β>1及收敛序列{t_k}:t_0=0,t_1≥α,t_(k 1)=t_(k φ)(β(t_k-t_(k-1))(k=1,2,…),则存在     

正规强可遮空间的逆极限性质

证明了如下结果:设X=lim/←{Xσ,πσρ,Λ),|A|=λ,并且每个投射πσ∶X→Xσ是开满的,(A)若X是λ-仿紧的并且每个Xσ是正规强可遮空间,则X是正规强可遮空间;(B)若X是遗传λ-仿紧的并且每个Xσ是遗传正规且遗传强可遮空间,则X是遗传正规强可遮空间.     

单调凝聚映象及其不动点

<正> 凝聚映象是较全连续映象和压缩映象都要更为广泛的映象,甚至上述二映象的和映象也是凝聚映象.它在众多的实际问题中起着重要的作用,例如在无界域上椭圆型偏微分方程理论中就是如此([7],[8]).它已成为一类很重要的非线性算子.本文对单调凝聚映象进行较深入的讨论,对其建立了简单迭代序列,在相当一般和易于检验的条件下,证明了收敛性,从而导出一些不动点定理.在此基础上,对单调凝聚映象族f(λ,x)(λ为实参数)进行考察,讨论了极小不动点集{x(λ)}的性质.     

von Neumann代数上非线性强保交换映射

设M是作用在维数大于2的复可分Hilbert空间上的因子von_Neumann代数.本文证明了M上的每个非线性强保交换满射Φ都具有形式:存在常数λ∈{-1,1)和非线性函数h:M→C使得对任意A∈M,有Φ(A)=λA+h(A)I.     

单调减凝聚映象的不动点定理

郭大钧[1]和[4]给出了单调减全连续映象的不动点定理,并用于核物理中一个非线性积分方程的求解。本文把它拓广到凝聚映象,从而拓广了[1]和[4]的结果。 定理 设E是Banach空间,P是E中一个正规锥,A:P→P是单调减凝聚映象。那末(i)A在P中至少有一个不动点x~*,θ≤x~*≤Aθ;(ⅱ)A~2在P中的不动点唯一时,A在P中的不动点唯一并且对任何x_0∈P作迭代序列     

关于压缩映象的一个未解决的问题及一个新的不动点定理

§1.引言 设(X,d)是一完备度量空间,T是映X到X的映象.按照Rhoades的说法,T称为第(25)类的压缩映象,如果T满足下面的条件:对一切的x,y∈X,x≠y, d(Tx,Ty)相似文献   

一类高阶奇点位置确定的数值方法

1.引言 设X是实Hilbert空间,D是X中的开集.F:D×R→X是二次连续可微的非线性算子,R是实数域.考察算子方程: F(x,λ)=0(x,λ)∈D×R.(1.1)如果在(1.1)的解(x_0,λ_0)处F关于x的Frechet导数F_x(x_0,λ_0)是X到X上的线性同胚,则称(x_0,λ_0)是(1.1)的正常解.否则,(1.1)的解称为奇点.对于由正常解组成的连续     

A dynamical method for the calculation of Nash-equilibria in n-person games

In this paper, we are concerned with the calculation of Nash-equilibria in non-cooperative n-person games. For this purpose, we construct a continuous mapping of the Cartesian product of the strategy sets of the players into itself such that the fixed points of this mapping are Nash-equilibria. This gives rise to an iteration method for the calculation of fixed points of this mapping which leads to Nash-equilibria, if it converges. As important special cases Bi-matrix games and evolution matrix games are considered.     

构造非线性映射不动点的迭代法

为了构造非线性映射的不动点,许多作者对Mann迭代法进行了研究.后来Ishikawa推广了Mann迭代法,对Hilbert空间H的紧凸子集D的李卜西兹拟压缩映射T,证明了新的迭代法{x_n}强收敛于T的一不动点,{x_n}被定义为     

Convergence analysis of a hybrid Mann iterative scheme with perturbed mapping for variational inequalities and fixed point problems

The purpose of this article is to investigate the problem of finding a common element of the set of fixed points of a non-expansive mapping and the set of solutions of the variational inequality problem for a monotone, Lipschitz continuous mapping. We introduce a hybrid Mann iterative scheme with perturbed mapping which is based on the well-known Mann iteration method and hybrid (or outer approximation) method. We establish a strong convergence theorem for three sequences generated by this hybrid Mann iterative scheme with perturbed mapping. Utilizing this theorem, we also construct an iterative process for finding a common fixed point of two mappings, one of which is non-expansive and the other taken from the more general class of Lipschitz pseudocontractive mappings.     

一致光滑Banach空间中一类非线性映象的迭代过程

本文引入了广义Lipschitz的概念，研究了广义Lipschitz强增生映象的Mann型迭代和Ishikawa型迭代过程的收敛性，所得结果统一和扩展了近期相关结果．     

Smooth solutions for one‐dimensional relativistic radiation hydrodynamic equations

In this research article, we investigated the existence of local smooth solutions for relativistic radiation hydrodynamic equations in one spatial variable. The proof is based on a classical iteration method and the Banach contraction mapping principle. However, because of the complexity of relativistic radiation hydrodynamics equations, we first rewrite this system into a semilinear form to construct the iteration scheme and then use left eigenvectors to decouple the system instead of applying standard energy method on symmetric hyperbolic systems. Different from multidimensional case, we just use the characteristic method, which can keep the properties of the initial data. Copyright © 2015 John Wiley & Sons, Ltd.     

Approximating Fixed Points of Generalized α-Nonexpansive Mappings in Banach Spaces

We introduce a new type of nonexpansive mappings and obtain a number of existence and convergence theorems. This new class of nonlinear mapping properly contains nonexpansive, Suzuki-type generalized nonexpansive mappings and partially extends firmly nonexpansive and α-nonexpansive mappings. Also, this class of mapping need not be continuous. Some useful examples are presented to illustrate facts. Some prominent iteration processes are also compared using numerical computations.     

Viscosity approximation methods for pseudo-contractive semigroups in Banach spaces

We study the strong convergence of two viscosity iteration processes for pseudo-contractive semigroup and for ?$?$-strongly pseudo-contractive mapping in uniformly convex Banach spaces with uniformly Gâteaux differentiable norm. As special cases, we get strong convergence of two viscosity iteration processes for approximating common fixed points of nonexpansive semigroups in certain Banach spaces. The results presented in this paper extend and generalize previous results.     

A class of two‐stage iterative methods for systems of weakly nonlinear equations

The discretizations of many differential equations by the finite difference or the finite element methods can often result in a class of system of weakly nonlinear equations. In this paper, by applying the two-tage iteration technique and in accordance with the special properties of this weakly nonlinear system, we first propose a general two-tage iterative method through the two-tage splitting of the system matrix. Then, by applying the accelerated overrelaxation (AOR) technique of the linear iterative methods, we present a two-tage AOR method, which particularly uses the AOR iteration as the inner iteration and is substantially a relaxed variant of the afore-presented method. For these two classes of methods, we establish their local convergence theories, and precisely estimate their asymptotic convergence factors under some suitable assumptions when the involved nonlinear mapping is only B-differentiable. When the system matrix is either a monotone matrix or an H-matrix, and the nonlinear mapping is a P-bounded mapping, we thoroughly set up the global convergence theories of these new methods. Moreover, under the assumptions that the system matrix is monotone and the nonlinear mapping is isotone, we discuss the monotone convergence properties of the new two-tage iteration methods, and investigate the influence of the matrix splittings as well as the relaxation parameters on the convergence behaviours of these methods. Numerical computations show that our new methods are feasible and efficient for solving the system of weakly nonlinear equations. This revised version was published online in June 2006 with corrections to the Cover Date.     

A Skorokhod Problem formulation and large deviation analysis of a processor sharing model

Generalized processor sharing has been proposed as a policy for distributing processing in a fair manner between different data classes in high-speed networks. In this paper we show how recent results on the Skorokhod Problem can be used to construct and analyze the mapping that takes the input processes into the buffer content. More precisely, we show how to represent the map in terms of a Skorokhod Problem, and from this infer that the mapping is well defined (existence and uniqueness) and well behaved (Lipschitz continuity). As an elementary application we present some large deviation estimates for a many data source model. This revised version was published online in June 2006 with corrections to the Cover Date.     

A two-step matrix splitting iteration paradigm based on one single splitting for solving systems of linear equations

For solving large sparse systems of linear equations, we construct a paradigm of two-step matrix splitting iteration methods and analyze its convergence property for the nonsingular and the positive-definite matrix class. This two-step matrix splitting iteration paradigm adopts only one single splitting of the coefficient matrix, together with several arbitrary iteration parameters. Hence, it can be constructed easily in actual applications, and can also recover a number of representatives of the existing two-step matrix splitting iteration methods. This result provides systematic treatment for the two-step matrix splitting iteration methods, establishes rigorous theory for their asymptotic convergence, and enriches algorithmic family of the linear iteration solvers, for the iterative solutions of large sparse linear systems.