Ekeland’s Variational Principle and the Mountain Pass Lemma

Ekeland’s variational principle is a fundamental theorem in nonconves analysis. Its general statement is as the following:Ekeland’s Variational Principle"’a:. Let V be a complete metric space, and F: F—*-RU{ + °°} a lower semicontinuous function, not identically +00 and bounded from, below. Let s>0 be given, and a point u^V such thatF(u)<infF+e.vThen there exists some point v ￡ V such that

THE REGULARITY OF QUASI-MINIMA AND ω-MINIMA OF INTEGRAL FUNCTIONALS

In this article, we have two parts. In the first part, we are concerned with the locally Hlder continuity of quasi-minima of the following integral functional ∫Ωf（x, u, Du）dx, （1） where Ω is an open subset of Euclidean N-space （N ≥ 3）, u：Ω → R,the Carath′eodory function f satisfies the critical Sobolev exponent growth condition ｜Du｜^p＊ ｜u｜^p＊-a（x） ≤ f（x,u,Du） ≤ L（｜Du｜^p＋｜u｜^p＊ ＋ a（x））, （2） where L≥1, 1pN,p^＊ = Np/N-p , and a（x） is a nonnegative function that lies in a suitable Lp space. In the second part, we study the locally Hlder continuity of ω-minima of （1）. Our method is to compare the ω-minima of （1） with the minima of corresponding function determined by its critical Sobolev exponent growth condition. Finally, we obtain the regularity by Ekeland’s variational principal.

一类非齐次Schrodinger-Poisson系统解的存在性

研究一类非齐次Schrodinger-Poisson系统{-△u+V(x)u+φ(x)u=f(u)+g(x),x∈R^(3)-△φ=u^(2),x∈R^(3)。当V(x)为径向对称位势,非齐次扰动项g(x)的范数足够小时,通过Ekeland’s变分原理和结合单调性方法的山路定理,证明了该系统解的存在性;当V(x)为强制位势且f(u)为奇函数时,通过(sP.S)_(c)条件和对称山路引理构造一趋于无穷大的临界值序列,获得系统无穷多解的存在性。

A General Vectorial Ekeland's Variational Principle with a P-distance

In this paper, by using p-distances on uniform spaces, we establish a general vectorial Ekeland variational principle （in short EVP）, where the objective function is defined on a uniform space and taking values in a pre-ordered real linear space and the perturbation involves a p-distance and a monotone function of the objective function. Since p-distances are very extensive, such a form of the perturbation in deed contains many different forms of perturbations appeared in the previous versions of EVP. Besides, we only require the objective function has a very weak property, as a substitute for lower semi-continuity, and only require the domain space （which is a uniform space） has a very weak type of completeness, i.e., completeness with respect to a certain p-distance. Such very weak type of completeness even includes local completeness when the uniform space is a locally convex topological vector space. From the general vectorial EVP, we deduce a general vectorial Caristi＇s fixed point theorem and a general vectorial Takahashi＇s nonconvex minimization theorem. Moreover, we show that the above three theorems are equivalent to each other. We see that the above general vectorial EVP includes many particular versions of EVP, which extend and complement the related known results.

EKELAND'S VARIATIONAL PRINCIPLE AND CARISTI'S FIXED POINT THEOREM IN PROBABILISTIC METRIC SPACE

The main purpose of this paper is to establish the Ekeland’s variational principle andCaristi’s fixed point theorem in probabilistic metric spaces and to give a direct simple proofof the equivalence between these two theorems in the probabilistic metric space. The resultspresented in this paper generalize the corresponding results of [9--12].

APPROXIMATE OPTIMAL BIRTH CONTROL OF POTULATION SYSTEMS

We consider optimal birth control for the McKendrick equation of population dyna-mics.It consists of optimizing a system described by a first order partial differential equationwith nonlo-cal bilinear boundary control.Approximate minimum principles are obtained usingEkeland’s vari ational principle.

具有毒素作用和年龄结构的种群模型的最优控制（英文）

本文研究了污染环境下具有年龄结构的三竞争种群的最优控制问题。即讨论了小环境容量下具有年龄结构和毒素作用的种群模型。利用不动点定理研究了该模型解的存在唯一性;采用法锥技巧得到了控制的最优性条件;同时利用Ekeland's变分原理得到了最优控制的存在性。

一类非局部问题正解的存在性与多重性

【目的】研究一类非局部问题在无界域上的可解性,探索其正解的存在性和多重性条件。【方法】利用Ekeland’s变分原理和山路引理等变分方法,分析该问题对应泛函的几何结构。【结果】获得了两个正解的存在性,其中一个是负能量解和一个是正能量解。【结论】结果表明,该类非局部问题具有变分结构,可以通过变分法技巧加以研究。此外,相关结果对相关领域的数学模型提供了理论支撑。