Second-order methods for accretive inclusions in a Banach space

We consider equations with set-valued accretive operators in a Banach space, whose solutions are understood in the sense of inclusion. By using the resolvent, we reduce these equations to equations with single-valued operators. For the constructed problems, we suggest a continuous and an iteration second-order method and obtain sufficient conditions for their strong convergence in some class of Banach spaces.     

An Extension of Set-Valued Contraction Principle for Mappings on a Metric Space with a Graph and Application

In this paper, we obtain an existence theorem for fixed points of contractive set-valued mappings on a metric space endowed with a graph. This theorem unifies and extends several fixed point theorems for mappings on metric spaces and for mappings on metric spaces endowed with a graph. As an application, we obtain a theorem on the convergence of successive approximations for some linear operators on an arbitrary Banach space. This result yields the well-known Kelisky–Rivlin theorem on iterates of the Bernstein operators on C[0,1].     

向量集值映射的共轭对偶

借助抽象算子将共轭映射的概念的到抽象空间,引入了集值映射的共轭映射和次梯度,据此讨论了集值映射共轭对偶的全局稳定性。     

Viable solutions of set-valued stochastic equation

The existence of viable solutions to set-valued Itô equation, i.e., solutions remaining at any time in a ilxed sublet of a slate space, is established for a functional inclusion with dissipative set-valued operators which need not he Lipsehitz continuous nor have to satisfy the Pardoux “monotone” property     

First-order regularization methods for accretive inclusions in a Banach space

Equations with set-valued accretive operators in a Banach space are considered. Their solutions are understood in the sense of inclusions. By applying the resolvent of the set-valued part of the equation operator, these equations are reduced to ones with single-valued operators. For the constructed problems, a regularized continuous method and a regularized first-order implicit iterative process are proposed. Sufficient conditions for their strong convergence are obtained in the case of approximately specified data.     

Random fixed points of set-valued operators

Some random fixed point theorems for set-valued operators are obtained. The measurability of certain marginal maps is also studied. The underlying measurable space is not assumed to be a Suslin family.

     

Existence Theorems for Set-valued Operators in Banach Spaces

In this paper, we study the problem of existence of zero points for set-valued operators in Banach spaces. We present a simple condition which can be used to verify that under some conditions, set-valued operators have zero points. Furthermore, we derive the surjectivity result and the Kakutani fixed point theorem by using this condition.      

Non-compact generalized variational inequalities for quasi-monotone and hemi-continuous operators with applications

Some results are obtained for non-compact cases in topological vector spaces for the existence problem of solutions for some set-valued variational inequalities with quasi-monotone and lower hemi-continuous operators, and with quasi-semi-monotone and upper hemi-continuous operators. Some applications are given in non-reflexive Banach spaces for these existence problems of solutions and for perturbation problems for these set-valued variational inequalities with quasi-monotone and quasi-semi-monotone operators. This revised version was published online in June 2006 with corrections to the Cover Date.     

The minimum mean square estimator of integrable variables under sublinear operators

In this paper, we study the minimum mean square estimator for non-bounded random variables under sublinear operators. The existence and uniqueness of the minimum mean square estimator are obtained. Several properties of the minimum mean square estimator for non-bounded random variables are proved under some mild assumptions.     

Steiner选择和算子的集值扩张(Ⅰ)——理论结果

提出了一种从连续函数空间到连续集值函数空间中扩张算子的方法.这种扩张是通过Steiner集值函数选择法得到的.此外,还研究了其性质及该类算子序列的收敛特性.在文章的第(Ⅱ)部分,还将给出在逼近理论中的一些应用.     

A necessary extremality condition for a set-valued stochastic control problem

For a controlled stochastic dynamic system with set-valued drift coefficient and a terminal cost functional we derive a necessary extremality condition in form of a minimum principle.     

Steiner选择和算子的集值扩张(Ⅱ)——对逼近理论的应用

在(Ⅰ)的基础上,得出对集值函数逼近理论的某些应用:Korovkin型定理,一种将经典逼近算子扩张到集值族的方法,以及Jackson估算.     

Accretive operators which are always single-valued in normed spaces

Set-valued accretive operators in Banach spaces have been extensively studied for several decades. Our main purpose in this paper is to establish a quite revealing result that says that every set-valued lower semi-continuous accretive mapping defined on a normed space is, indeed, single-valued on the interior of its domain. No reference to the well-known Michael’s Selection Theorem is needed. This result is used to extend known theorems concerning the existence of zeros for such operators, as well as showing existence of solutions for variational inclusions.     

集值映射的连续选择与线性算子的齐性右逆

本文对于取值在Ｂａｎａｃｈ空间的几乎下半连续映射引入两个相关的下半连续闭凸集值映射,得到集值映射的连续选择存在性的若干特征,从而将 Ｄｅｕｔｓｃｈ Ｅ,和Ｋｅｎｄｅｒｏｖ Ｐ,Ｄｅ Ｂｌａｓｔ Ｆ．Ｓ．和 Ｍｙｊａｋ Ｊ,Ｐｒｚｅｓｌａｗｓｋｉ Ｋ．和 Ｒｙｂｉｎｓｋｉ Ｌ Ｅ,Ｇｕｔｅｖ Ｖ．等人以及作者自己的关于连续选择存在性的结果作为推论给出．并用这些结论讨论了在开映射定理不成立的。情况下从Ｂａｎａｃｈ空间到赋范空间上线性连续算子的齐性右逆存在问题．     

Existence of zero points for pseudomonotone operators in Banach spaces

The purpose of this paper is to study the existence of zero points for set-valued pseudomonotone operators in a Banach space by using a new condition which was recently proposed by the authors (Matsushita and Takahashi, Set-Valued Analysis 15:251–264, 2007).      

Stability of Quasimonotone Variational Inequality Under Sign-Continuity

Whenever the data of a Stampacchia variational inequality, that is, the set-valued operator and/or the constraint map, are subject to perturbations, then the solution set becomes a solution map, and the study of the stability of this solution map concerns its regularity. An important literature exists on this topic, and classical assumptions, for monotone or quasimonotone set-valued operators, are some upper or lower semicontinuity. In this paper, we limit ourselves to perturbations on the constraint map, and it is proved that regularity results for the solution maps can be obtained under some very weak regularity hypothesis on the set-valued operator, namely the lower or upper sign-continuity.     

关于α-凸凹混合单调算子的不动点定理

引入了α-凸凹混合单调算子的概念.借助于集值分析的方法,利用锥理论讨论了这类混合单调算子,得到了若干α-凸凹混合单调算子不动点的存在性和唯一性定理.     

Characterizations of the nonemptiness and compactness for solution sets of convex set-valued optimization problems

In this paper, we first derive several characterizations of the nonemptiness and compactness for the solution set of a convex scalar set-valued optimization problem (with or without cone constraints) in which the decision space is finite-dimensional. The characterizations are expressed in terms of the coercivity of some scalar set-valued maps and the well-posedness of the set-valued optimization problem, respectively. Then we investigate characterizations of the nonemptiness and compactness for the weakly efficient solution set of a convex vector set-valued optimization problem (with or without cone constraints) in which the objective space is a normed space ordered by a nontrivial, closed and convex cone with nonempty interior and the decision space is finite-dimensional. We establish that the nonemptiness and compactness for the weakly efficient solution set of a convex vector set-valued optimization problem (with or without cone constraints) can be exactly characterized as those of a family of linearly scalarized convex set-valued optimization problems and the well-posedness of the original problem.     

Accretive operators which are always single-valued in normed spaces

Set-valued accretive operators in Banach spaces have been extensively studied for several decades. Our main purpose in this paper is to establish a quite revealing result that says that every set-valued lower semi-continuous accretive mapping defined on a normed space is, indeed, single-valued on the interior of its domain. No reference to the well-known Michael’s Selection Theorem is needed. This result is used to extend known theorems concerning the existence of zeros for such operators, as well as showing existence of solutions for variational inclusions.     

Martingale representation theorem for set-valued martingales

The present paper contains a martingale representation theorem for set-valued martingales defined on a filtered probability space with a filtration generated by a Brownian motion. It is proved that such type martingales can be defined by some generalized set-valued stochastic integrals with respect to a given Brownian motion. The main result of the paper is preceded by short part devoted to the definition and some properties of generalized set-valued stochastic integrals.