REITERATED HOMOGENIZATION OF NONLINEAR MONOTONE OPERATORS

61. IntroductionLet us consider the clajss of partial differential equations of the form--div(a.(x, Du.)) ~ f on fi, us E Wt,p(fl), (1.1)where a6 is increasingly oscillating as E -- 0, fi is an open bounded subset of R", 1 < p < cot1/p 1/q = 1 and f E W--"q(fl). The homogenization problem for (l.1) consists of the studyof the asymptotic behavior of solutions net as e - 0. In many important cases nE convergesweakly in WI'p(n) to the solution no of the homogenized problem--div(b(Duo)) = f …     

R^N中的非线性退化椭圆方程粘性解的存在性

本文研究了Ｒ＾Ｎ中的非线性退化椭圆型方程Ｆ（Ｄｕ，Ｄ＾２ｕ）＋ｕｓ＝ｆ的非负粘性解的存在性，其中ｓ〉０，Ｆ满足某些关于ｐ的条件，本文在下面的条件下证明了存在性；１．ｓ〉ｐ－１，ｆ在无穷远处不需要增长条件；２．０〈ｓ≤ｐ－１，ｆ在无穷远处具有某种增长条件。     

椭圆问题的非线性边界条件均匀化

在本文我们讨论了在等值面边值问题中的非线性边界条件的均匀化,推广了相应的边界条件均匀化结果,而且可应用到用于处理热敏电阻问题中的一类非线性非局部边值问题的边界条件均匀化问题。     

双尺度收敛和拟线性抛物方程的均匀化

利用Ｆｏｕｒｉｅｒ分析的某些技巧，得到殆周期国数的一些新性质，在此基础上将均匀化理论中的双尺度收敛方法推广到殆周期振荡的情形．然后利用一些新技巧讨论了殆周期振荡的拟线性方程的均匀化问题，得到了相应的弱收敛和纠正子结果．     

HOLDER ESTIMATES FOR A CLASS OF DEGENERATE ELLIPTIC EQUATIONS

In this paper we study the regularity theory of the solutions of a class of degenerate elliptic equations in divergence form. By introducing a proper distance and applying the compactness method we establish the HSlder type estimates for the weak solutions.     

一类非线性椭圆方程的解的对称性

本义使用Moving Planes方法证明方程 当x∈R2时, 当x∈R2时的光滑解关于R2中的某一点是对称的.     

一类非线性椭圆方程的解的对称性

本文使用Moving Planes方法证明方程{△x(x)+eu(x)(1-δeu(x))=0, 当x∈R2时∫R2eu(x)(1-δeu(x))dx＜+∞,且δeu(x)≤1,当x∈R2时}的光滑解关于R2中的某一点是对称的.     

一类退缩的椭圆型方程弱解的正则性

本文给出了一类退缩的拟线性椭圆型方程－Ｄｉｖ「↓ｕ｜＾ｐ－２↓ｕ＋Ｆ（ｘ,ｕ）」＝Ｂ（ｘ,ｕ,↓ｕ）在Ｗ＾１,ｐ（Ω）中弱解的Ｃ＾１,λｌｏｃ（Ω）正则性,其中Ω为Ｒ＾Ｎ中行一区域。     

CONVERGENCE OF BSDEs AND HOMOGENIZATION OF ELLIPTIC SEMI-LINEAR PDEs

We present a result of weak convergence for Backward Stochastic Differential Equations with a random terminal time. Then we can deduce results of homogenization for elliptic semi-linear PDEs with random or periodic coefficients and whose non-linearity may have a quadratic growth in the gradient.     

二阶非线性椭圆型微分方程解的振动性质

在R^n的一个外区域Ω上研究二阶非线性椭圆型微分方程的解的振动性质，得到了保证该方程所有解均振动的新的充分条件。     

MULTISCALE HOMOGENIZATION OF NONLINEAR HYPERBOLIC EQUATIONS WITH SEVERAL TIME SCALES

We study the multiscale homogenization of a nonlinear hyperbolic equation in a periodic setting.We obtain an accurate homogenization result.We also show that as the nonlinear term depends on the microscopic time variable,the global homogenized problem thus obtained is a system consisting of two hyperbolic equations.It is also shown that in spite of the presence of several time scales,the global homogenized problem is not a reiterated one.     

EXISTENCE OF DISCONTINUOUS SOLUTIONS FOR A DOUBLY DEGENERATE ELLIPTIC EQUATIONS ON $R^N$

It is demonstrated that under the hypotheses I—III the problem $\[\left\{ {\begin{array}{*{20}{c}} {div((k(U) + \varepsilon )|DU{|^{M - 1}}DU) = f(|x|,U) + \varepsilon U{\text{ }}in{\text{ }}{R^N},N > 1,{\text{ (1}}{\text{.1}}{{\text{)}}_\varepsilon }} \ {U(0) > 0,U(x) \geqslant 0{\text{ on }}{R^N},U(x) \to 0{\text{ as }}|x| \to + \infty {\text{ }}(1.2)} \end{array}} \right.\]$ for each fixed $\epsilon >0$ has infinitely many distinct radially symmetric solutions $U_\epsilon=V_\epsilon(|x|)$ such that $V_\epsilon(s),s^{N-1}(k(V_\epsilon(s))+\epsilon)|V''(s)|^{M-1}V''_\epsilon(s)\in C[0,+\infinity)\capC^1(0,+\infinity)$, $\[\left\{ {\begin{array}{*{20}{c}} {({s^{N - 1}}(k({V_\varepsilon }(s)) + \varepsilon )|V''(s){|^{M - 1}}V''(s)) = {\varepsilon ^{N - 1}}(f(s,{V_\varepsilon }(s)) + \varepsilon {V_\varepsilon }(s))for{\text{ }}s > 0,{{(1.3)}_\varepsilon }} \ {{V_\varepsilon }(0) = B > 0,{V_\varepsilon }(s) \geqslant 0{\text{ for }}s > 0,and{\text{ }}{V_\varepsilon }( + \infty ) = 0,(1.4)} \end{array}} \right.\]$ where B is a positive number chosen arbitrarily, which extends the result in [3]. In particular, the author proves that $U_0(x)=V_0(|x|)$ is a weak solution of the problem $(l.l)_0-(1.2)$.     

一类奇异椭圆方程的正解

研究一类奇异椭圆方程问题。利用变分方法和锥理论中的混合单调方法,证明了奇异方程正解的存在性。     

二阶完全非线性蜕化抛物方程

本文研究了一个空间变量的二阶完全非线性蜕化抛物方程ｕｔ＝Ｆ（ｕｘｘ，ｕｘ，ｘ，ｔ）的第一边值问题。在仅要求Ｆ及其一阶导数满足结构条件的情形，给出了蜕化问题连续解的存在唯一性。这个工作将渗流方程的结果推广到非常一般的情形。     

INITIAL TRACE OF SOLUTIONS FOR A DOUBLY NONLINEAR DEGENERATE PARABOLIC EQUATIONS

In this note, we study the existence of an initial trace of nonnegative solutions for the following problem ut-div(|▽um|p-2▽um)+uq = 0 in QT = Ω× (0, T ). We prove that the initial trace is an outer regular Borel measure, which may not be locally bounded for some values of parameters p, q, and m. We also study the corresponding Cauchy problems with a given generalized Borel measure as initial data.     

具间断系数拟线性退化椭圆方程在可控增长下的正则性

对于具有VMO间断系数的散度型拟线性退化椭圆型方程,考虑了低阶项微分项在可控制增长条件下的弱解梯度的Morrey空间L^p,λ局部正则性,从而在已知数据正则性提高的条件下得到弱解具有优化Hlder指数的Hlder连续性结果。     

ASYMPTOTIC BEHAVIOR OF SOLUTIONS OF SECOND ORDER NONLINEAR ELLIPTIC DIFFERENTIAL EQUATIONS

1 IntroductionTlle problem of obtaining sufficient conditions to ensure that al1 solutions of second orderordinary differential equations with an "integrally smal" coefficiellt are oscillatory'has beenstudied by many authors [cft1-4]] and other referellces cited therein. Recently, the paPers[cf[5],[6]] have discussed the asymptotiC properties of the solutions Of the follOwing equatious(a(f)W(x)X,), q(t)i(x) = c(t),(g(f, T)X,), q(t)f(x) = e(t),here q(f) is allowed to challge sign. In thi…     

THE FIRST BOUNDARY VALUE PROBLEM FOR A CLASS OF QUASILINEAR DEGENERATE ELLIPTIC EQUATIONS

In this paper, the first boundary value problem for quasilinear equation of the form △A（u,x）＋∑i=1^m δb^i（u,x）/δxi＋c（u,x）=0,Au（u,x） ≥0is studied. By using the compensated compactness theory, some results on the existence of weak solution are established. In addition, under certain condition the uniqueness of solution is proved.