On the Tikhonov Well-Posedness of Concave Games and Cournot Oligopoly Games

The purpose of this paper is to investigate whether theorems known to guarantee the existence and uniqueness of Nash equilibria, provide also sufficient conditions for the Tikhonov well-posedness (T-wp). We consider several hypotheses that ensure the existence and uniqueness of a Nash equilibrium (NE), such as strong positivity of the Jacobian of the utility function derivatives (Ref. 1), pseudoconcavity, and strict diagonal dominance of the Jacobian of the best reply functions in implicit form (Ref. 2). The aforesaid assumptions imply the existence and uniqueness of NE. We show that the hypotheses in Ref. 2 guarantee also the T-wp property of the Nash equilibrium.As far as the hypotheses in Ref. 1 are concerned, the result is true for quadratic games and zero-sum games. A standard way to prove the T-wp property is to show that the sets of -equilibria are compact. This last approach is used to demonstrate directly the T-wp property for the Cournot oligopoly model given in Ref. 3. The compactness of -equilibria is related also to the condition that the best reply surfaces do not approach each other near infinity.     

Approximations and Well-Posedness in Multicriteria Games

First, sufficient conditions of minimal character are given which guarantee the sequential closedness of the set-valued function defined by the parametric weak-multicriteria Nash equilibria of a parametric multicriteria game, that is to say: a convergent sequence of parametric weak-multicriteria Nash equilibria, corresponding to an approximate value of the parameter x_n, converges to a weak-multicriteria Nash equilibrium corresponding to the limit value x of the sequence (x_n)_n. Then, approximating sequences and parametrically well-posedness for a multicriteria game are introduced and investigated.     

Hadamard良定性的统一研究

对一些非线性问题的Hadamard良定性给出一个统一的定理，应用这个定理，可以容易地推出KyFan点，Nash平衡点等的Hadamard良定性。此外，最优化问题和鞍点问题的通用良定性也被研究给出了两个定理。     

An ordinal well-posedness property for Nash equilibria

The aim of this article is to give, for Nash equilibria, a well-posedness criterion in the form of an ordinal property. This property is important for games because it captures the case when players' decisions depend on preferences and not on a special choice of a utility function. The ordinal characteristics of this well-posedness criterion comes from considering value-bounded approximate equilibria.     

非静力旋转流体方程初值问题的适定性

应用分层理论所提供的方法,通过对非静力旋转流体方程这个数学模型本身的拓扑性质进行系统的理论分析和研究,来讨论对于这个方程的初值问题的几种不同提法以及相应的适定性问题．     

弱向量均衡问题的含参适定性

本文在实 Banach 空间中研究了弱向量均衡问题的两种适定性.给出了该问题唯一适定与适定的距离刻划.在适当条件下证明了弱向量均衡问题的唯一适定性等价于解的存在性与唯一性.最后, 文章在有限维空间给出了弱向量均衡问题适定的充分性条件.     

一类广义层流方程组的初值问题的局部适定性

讨论层流理论中描述比重相近的层流间相互作用的方程组的广义方程组．通过引进一类函数空间和一系列先验估计,应用不动点原理,分别得到该类广义层流方程组的初值问题在H^s(R),s≥1的局部适定性．     

Well-Posedness of MHD Equations in Sobolev-Gevery Space

This paper is devoted to the study of the 3D incompressible magnetohydrodynamic system. We prove the local in time well-posedness for any large initial data in $\dot{H}_{a,1}^{1}({\mathbb{R}}^{3})$ or $H_{a,1}^{1}({\mathbb{R}}^{3})$. Furthermore, the global well-posedness of a strong solution in $\tilde{L}^{\infty}(0,T;H_{a,1}^{1}({\mathbb{R}}^{3}))\cap L^{2}(0,T;\dot{H}_{a,1}^{1}({\mathbb{R}}^{3})\cap \dot{H}_{a,1}^{2}({\mathbb{R}}^{3}))$ with initial data satisfying a smallness condition is established.     

Unified Approaches to Well-Posedness with Some Applications

We present unified approaches to Hadamard and Tykhonov well-posedness. As applications, we deduce Tykhonov well- posedness for optimization problems, Nash equilibrium point problems and fixed point problems etc. Especially, by applying such approaches, we deal with the well- posedness as stated in (Lignola and Morgan (2000), Journal of Global Optimization 16, 57–67) in which Lignola and Morgan investigated directly and intensively Tykhonov types of well- posedness for optimization problems with constraints defined by variational inequalities, namely, generalized well- posedness and strong well- posedness. We give some sufficient conditions for Hadamard well- posedness of such problems and deduce relations between Hadamard type and Tykhonov type of well- posedness. Finally, as corollaries, we derive generalized well- posedness and strong well- posedness for these problems.     

一类广义层流方程初值问题的整体适定性

讨论了刻画层流问题中比重相近的层间相互作用的数学模型的初值问题.通过引进一类函数空间并证明该初值问题的解在所述空间上的一系列先验估计,得到了该初值问题在初值属于Hs(R)(s≥1)时的整体适定性.     

向量值优化问题的适定性

将向量值优化问题的适定性理论推广到具有W-距离的拟度量空间中,给出B-适定性及DH-适定性的概念,并得到相应的判别准则．定义一类非线性标量化函数,利用这类标量化函数的性质将向量值优化问题转化为标量值优化问题,得到原问题与标量化问题的适定性之间的等价关系．     

Global Well-Posedness of the BCL System with Viscosity

The BCL system, a kind of equations governing the motion of the free surface of water waves in R3, is studied. Some results on the global existence, uniqueness and regularity of solutions to such system with small initial data are obtained.     

关于广义Benjamin－Ono方程的整体适定性

对Ｋ＞α＋３／２的广义Ｂｅｎｊａｍｉｎ－Ｏｎｏ方程，证明了当初值为小初值时相应的非线性初值问题的整体解的存在性以及唯一性．还得到了该整体在Ｌ２的意义下的渐近估计．     

The Tikhonov regularization method in elastoplasticity

The numerical simulation of the mechanical behavior of industrial materials is widely used for viability verification, improvement and optimization of designs. Elastoplastic models have been used to forecast the mechanical behavior of different materials. The numerical solution of most elastoplastic models comes across problems of ill-condition matrices. A complete representation of the nonlinear behavior of such structures involves the nonlinear equilibrium path of the body and handling of singular (limit) points and/or bifurcation points. Several techniques to solve numerical problems associated to these points have been disposed in the specialized literature. Two examples are the load-controlled Newton–Raphson method and displacement controlled techniques. However, most of these methods fail due to convergence problems (ill-conditioning) in the neighborhood of limit points, specially when the structure presents snap-through or snap-back equilibrium paths. This study presents the main ideas and formalities of the Tikhonov regularization method and shows how this method can be used in the analysis of dynamic elastoplasticity problems. The study presents a rigorous mathematical demonstration of existence and uniqueness of the solution of well-posed dynamic elastoplasticity problems. The numerical solution of dynamic elastoplasticity problems using Tikhonov regularization is presented in this paper. The Galerkin method is used in this formulation. Effectiveness of Tikhonov’s approach in the regularization of the solution of elastoplasticity problems is demonstrated by means of some simple numerical examples.     

一个供应链系统的可靠性模型的适定性分析

供应链系统是一个复杂的动态系统,许多影响因素的存在,使得供应链系统具有强烈的随机性,从而直接影响供应链系统的可靠性,我们通过分析供应链系统的状态之间的转移关系,引入增补变量法,用偏微分方程组建立了供应链系统的可靠性模型,并对该模型系统解的存在唯一性进行了讨论和证明.     

Tikhonov regularization of nonlinear III-posed problems in hilbert scales

In this paper we consider nonlinear ill-posed problems F(x) = y ₀, where x and y ₀ are elements of Hilbert spaces X and Y, respectively. We solve these problems by Tikhonov regularization in a Hilbert scale. This means that the regularizing norm is stronger than the norm in X. Smoothness conditions are given that guarantee convergence rates with respect to the data noise in the original norm in X. We also propose a variant of Tikhonov regularization that yields these rates without needing the knowledge of the smoothness conditions. In this variant F is allowed to be known only approximately and X can be approximated by a finite-dimensional subspace. Finally, we illustrate the required conditions for a simple parameter estimation problem for regularization in Sobolev spaces.     

A new variant of L-curve for Tikhonov regularization

In this paper we introduce a new variant of L-curve to estimate the Tikhonov regularization parameter for the regularization of discrete ill-posed problems. This method uses the solution norm versus the regularization parameter. The numerical efficiency of this new method is also discussed by considering some test problems.     

On Well-Posedness of 2D Dissipative Quasi-Geostrophic Equation in Critical Mixed Norm Lebesgue Spaces

We establish local and global well-posedness of the 2D dissipative quasi-geostrophic equation in critical mixed norm Lebesgue spaces. The result demonstrates the persistence of the anisotropic behavior of the initial data under the evolution of the 2D dissipative quasi-geostrophic equation. The phenomenon is a priori nontrivial due to the nonlocal structure of the equation. Our approach is based on Kato's method using Picard's iteration, which can be adapted to the multi-dimensional case and other nonlinear non-local equations. We develop time decay estimates for solutions of fractional heat equation in mixed norm Lebesgue spaces that could be useful for other problems.     

Identification of classes of differential games for which the open loop is a degenerate feedback Nash equilibrium

In general, it is clear that open-loop Nash equilibrium and feedback Nash equilibrium do not coincide. In this paper, we study the structure of differential games and develop a technique using which we can identify classes of games for which the open-loop Nash equilibrium is a degenerate feedback equilibrium. This technique clarifies the relationship between the assumptions made on the structure of the game and the resultant equilibrium.The author would like to thank E. Dockner, A. Mehlmann, and an anonymous referee for helpful comments.     

Caftan-Hartogs域上K(a)hler-Einstein度量与Bergman度量的等价

本文研究的是华罗庚域的特殊类型第二类Cartan-Hartogs域的不变Bergman度量与Kahler-Einstein度量的等价问题.引入一种与Bergman度量等价的新的完备的Kahler度量ωgλ,其Ricci曲率和全纯截取率具有负的上下界.然后应用丘成桐对Schwarz引理的推广证明ωgλ等价于Kahler-Einstein度量,从而得到了Bergman度量与Khhler-Einstein度量的等价,即丘成桐关于度量等价的猜想在第二类Cartan-Hartogs域上成立.