On Optimization Properties of Functions, with a Concave Minorant

We give a definition of the class of functions with a concave minorant and compare these functions with other classes of functions often used in global optimization, e.g. weakly convex functions, d.c. functions, Lipschitzian functions, continuous and lower semicontinuous functions. It is shown that the class of functions with a concave minorant is closed under operations mainly used in optimization and how a concave minorant can be constructed for a given function.     

FC-空间上的相交定理,不等式系解的存在定理

给出了没有任何凸结构的FC-空间上相交定理,并利用此结论得到了变分不等式解的存在定理.最后作为应用,给出了互为等价的集族的相交定理和不等式系的公共解的存在定理,所得结论推广和改进了文献中的相应结果.     

Nonlinear second order differential inclusions with a series of convex functions

In this paper, we study a class of second order differential inclusions attached to which the convex potential varies depending on the time, and the boundary conditions are described by the subdifferentials of convex functions. Applying the theory of lower semicontinuous, convex and proper functionals, and fixed points, we give some results about the representation of the subdifferential operators of some convex functionals and the existence of solutions for the boundary value problems.     

一般化凸空间上截口定理及其对择一不等式的应用

我们根据一般化凸空间上的KKM型定理得到了截口定理,然后作为它的应用讨论了若干个择一不等式.最后,引进了一个具体的一般化凸空间并在该空间上讨论了择一不等式解的存在性问题.     

集值映射的Nash平衡点的存在定理

本文引入了集值映射的Nash平衡点的概念，它以通常的Nash平衡点及Loose Nash平衡点为特例，并在紧和非紧的假设下，得到集值映射的Nash平衡点的存在定理，其中在非紧的情况下使用escaping序列的定义．     

集值映射的Nash平衡点集的通有稳定性

本文讨论了集值映射的Nash平衡点的存在及平衡点集的通有稳定性,得到大多数的集值映射的Nash平衡点集是稳定的。     

广义凸空间上重合点定理和极大极小不等式

利用已知的KKM型定理,在广义空间上得到若干个新的重合点定理和推广的Fan-Browder型不动点定理,并且讨论了Von Newmann-Sion型极大极小不等式.主要结果改进和推广了文献中的相应结论.     

KY FAN TYPE BEST APPROXIMATION THEOREM FOR A CLASS OF FACTORIZABLE MULTIFUNCTIONS

An existence result on Ky Fan type best approximation is proved. For this purpose, a class of factorizable multifunctions and the other one being a demicontinuous, relative almost quasi-convex, onto function on an approximately weakly compact, convex subset of Hausdorff locally convex topological vector space are used. As consequence, this result extends the best approximation results of Basha and Veeramani [8] and many others.     

Equilibria of noncompact abstract economies in general almost convex strategy spaces

We first extend the concept of almost convex condition and establish a fixed point theorem for correspondences with convex values only on an almost convex subset for their ranges. This generalizes both results of Himmelberg [C.J. Himmelberg, Fixed points of compact multifunctions, J. Math. Anal. Appl. 38 (1972) 205–207] and the result of Jafari and Sehgal [F. Jafari, V.M. Sehgal, An extension to a theorem of Himmelberg, J. Math. Anal. Appl. 327 (2007) 298–301]. Furthermore, applying it, we have existence theorems for equilibria of noncompact abstract economies in general almost convex strategy spaces. Our theorems generalize the corresponding results of Zhou [Jianxin Zhou, On the existence of equilibrium for abstract economies, J. Math. Anal. Appl. 193 (1995) 839–858], Tan and Wu [K.-K. Tan, Z. Wu, A note on abstract economies with upper semicontinuous correspondence, Appl. Math. Lett. 11 (5) (1998) 21–22] in several ways. In particular, we answer the question raised by Zhou in the reference cited above in the affirmative with weaker hypotheses.     

System of Generalized Vector Quasi-Equilibrium Problems with Applications to Fixed Point Theorems for a Family of Nonexpansive Multivalued Mappings

In this paper, we establish the existence theorems of the generalized vector quasi-equilibrium problems. From some existence theorem, we establish fixed point theorems for a family of lower semicontinuous or nonexpansive multivalued mappings. We also obtain the existence theorems of system of mixed generalized vector variational-like inequalities and existence theorems of the Debreu vector equilibrium problems and the Nash vector equilibrium problems.     

集值映射的广义对称向量拟平衡问题

本文提出了一类集值映射的广义对称向量拟平衡问题．利用非线性标量化函数,分别在局部凸Hausdorff拓扑向量空间和一般的Hausdorff拓扑向量空间中,证明了广义对称向量拟平衡问题解的存在性定理．     

可允许集上的广义向量拟均衡问题

主要讨论可允许集上的广义向量拟均衡问题,推广L in的一些结果.     

Convex extensions of the convex set valued maps

In this article the existence of the convex extension of convex set valued map is considered. Conditions are obtained, based on the notion of the derivative of set valued maps, which guarantee the existence of convex extension. The conditions are given, when the convex set valued map has no convex extension. The convex set valued map is specified, which is the maximal convex extension of the given convex set valued map and includes all other convex extensions. The connection between Lipschitz continuity and existence of convex extension of the given convex set valued map is studied.     

Generalized vector quasi-equilibrium problems with applications to common fixed point theorems and optimization problems

In this paper, we first establish the existence theorems of generalized vector quasi-equilibrium problems. From these results, we establish the existence theorems of common fixed point theorems for two multivalued maps and mathematical programs with an equilibrium constraint as applications.     

拓扑空间上的KKM定理,不动点定理,广义变分不等式

引进没有任何凸结构的拓扑空间上的广义R-KKM映射的定义并利用古典的KKM原理得到一般拓扑空间上的KKM型定理以及若干个变形结果,然后作为应用给出了非紧的拓扑空间上不动点定理和广义变分不等式解的存在性定理.     

On a Branch and Bound Algorithm for the Solution of a Family of Softening Material Problems of Mechanics with Applications to the Analysis of Metallic Structures

The variational formulation of mechanical problems involving nonmonotone,possibly multivalued, material or boundary laws leads to hemivariationalinequalities. The solutions of the hemivariational inequalities constitutesubstationarity points of the related energy (super)potentials. For theircomputation convex and global optimization algorithms have been proposedinstead of the earlier nonlinear optimization methods, due to the lack ofsmoothness and convexity of the potential. In earlier works one of us hasproposed an approach based on the decomposition of the solutions space intoconvex parts resulting in a sequence of convex optimization subproblems withdifferent feasible sets. In this case nonconvexity of the potential wasattributed to (generalized) gradient jumps. In order to treat softeningmaterial effects, in the present paper this method is extended to cover alsoenergy functionals where nonconvexity is caused by the existence of concavesections. The nonconvex minimization problem is formulated as d.c.(difference convex) minimization and an algorithm of the branch and boundtype based on simplex partitions is adapted for its treatment. Thepartitioning scheme employed here is adapted to the large dimension of theproblem and the approximation steps are equivalent to convex minimizationsubproblems of the same structure as the ones arising in unilateral problemsof mechanics. The paper concludes with a numerical example and a discussionof the properties and the applicability of the method.     

Second Order Nonlinear Evolution Inclusions Ⅰ： Existence and Relaxation Results

This is the first part of a work on second order nonlinear, nonmonotone evolution inclusions defined in the framework of an evolution triple of spaces and with a multivalued nonlinearity depending on both x（t） and x（t）. In this first part we prove existence and relaxation theorems. We consider the case of an usc, convex valued nonlinearity and we show that for this problem the solution set is nonempty and compact in C^1 （T, H）. Also we examine the Isc, nonconvex case and again we prove the existence of solutions. In addition we establish the existence of extremal solutions and by strengthening our hypotheses, we show that the extremal solutions are dense in C^1 （T, H） to the solutions of the original convex problem （strong relaxation）. An example of a nonlinear hyperbolic optimal control problem is also discussed.     

Existence of Solutions to Generalized Vector Quasi-Variational-Like Inequalities with Set-Valued Mappings

In this paper, we introduce and study a class of generalized vector quasi-variational-like inequality problems, which includes generalized nonlinear vector variational inequality problems, generalized vector variational inequality problems and generalized vector variational-like inequality problems as special cases. We use the maximal element theorem with an escaping sequence to prove the existence results of a solution for generalized vector quasi-variational-like inequalities without any monotonicity conditions in the setting of locally convex topological vector space.     

关于上半连续集值映象的连续选择问题

本文进一步研究了上半连续集值映象的连续选择问题．首先,用一反例指出Ａｕｂｉｎ Ｊ、 Ｐ［１］中一结果不能成立．另外,对上半连续映象的σ－可选择性给出了另一逼近形式的结果．