The Caffarelli Alternative in Measure for the Nondivergence Form Elliptic Obstacle Problem with Principal Coefficients in VMO

We study the obstacle problem with an elliptic operator in nondivergence form with principal coefficients in VMO. We develop all of the basic theory of existence, uniqueness, optimal regularity, and nondegeneracy of the solutions. These results, in turn, allow us to begin the study of the regularity of the free boundary, and we show existence of blowup limits, a basic measure stability result, and a measure-theoretic version of the Caffarelli alternative proven in [3 Caffarelli , L.A. ( 1977 ). The regularity of free boundaries in higher dimensions . Acta Math. 139 : 155 – 184 .[Crossref], [Web of Science ®] , [Google Scholar]].     

非线性椭圆障碍问题弱解的内部正则性

我们讨论具有C1,β障碍函数的非线性障碍问题弱解的内部正则性,得到了C1lo,cα的正则性结果.     

On Regularity and Singularity of Free Boundaries in Obstacle Problems

The author presents a simple approach to both regularity and singularity theorems for free boundaries in classical obstacle problems. This approach is based on the monotonicity of several variational integrals, the Federer-Almgren dimension reduction and stratification theorems, and some simple PDE arguments.     

Keldys-Fichera障碍问题

本文考查一个拟线性障碍问题，其系数具更高的增长阶，且边界条件是Ｋｅｌｄｙｓ－Ｆｉｃｈｅｒａ型     

分期付款购房模型及其抛物障碍问题

考虑常数利率条件下的分期付款购房模型,若风险资产市场价格服从几何布朗运动,则合约可以运用美式期权定价方法给出合理的价格.该文给出了分期付款购房合约定价的偏微分方程方法,得到一个一维抛物障碍问题,同时给出了贷款合约价格函数所联系的自由边界,并讨论了自由边界的单调性与有界性.     

Local existence of energy class solutions for the dirac—klein—gordon equations

Abstract

We show a method to eliminate a type of mixed asymptotics in certain free boundary problems, and give two examples of its application. It appears that these problems cannot be handled by the monotonicity formula of Alt et al. [Alt, H. W., Caffarelli, L. A., Friedman, A. (1984). Variational problems with two phases and their free boundaries. Trans. Am. Math. Soc. 282(2):431–461] or by the more recent monotonicity formula of Caffarelli et al. [Caffarelli, L. A., Jerison, D., Kenig, C. E. (2002). Some new monotonicity theorems with applications to free boundary problems. Ann. Math. (2) 155(2):369–404].     

关于一类半线性高阶障碍问题解的存在性与正则性

本文考虑一类带互补边界条件的四阶半线性椭圆型变分不等式,应用临界点理论,证明了当半线性项具有超线性增长时解的存在性,并利用L~p估计得到了解的正则性.     

椭圆方程障碍问题很弱解的全局正则性

在区域Ω的边界是r-Poincaré厚条件下,利用r-Poincaré厚的Sobolev不等式和极大函数表示的有关Sobolev函数的逐点不等式,来构造全局的Lipschitz型检验函数,得到一类拟线性椭圆方程-divA(x,u,Du) =0的Krφ,θ-障碍问题很弱解的全局正则性.     

An Obstacle Control Problem with a Source Term

   Abstract. An optimal control problem for an elliptic variational inequality with a source term is considered. The obstacle is the control, and the goal is to keep the solution of the variational inequality close to the desired profile while the H ¹ norm of the obstacle is not too large. The addition of the source term strongly affects the needed compactness result for the existence of a minimizer.     

An Obstacle Control Problem with a Source Term

Abstract. An optimal control problem for an elliptic variational inequality with a source term is considered. The obstacle is the control, and the goal is to keep the solution of the variational inequality close to the desired profile while the H ¹ norm of the obstacle is not too large. The addition of the source term strongly affects the needed compactness result for the existence of a minimizer.     

一类非齐次障碍问题很弱解的正则性

本文研究形如divA(x,▽u)=B(x,▽u)的非齐次椭圆算子的障碍问题,给出了二阶非齐次障碍问题解的定义,并利用Hodge分解,获得非齐次障碍问题的解及其导数的一些性质.     

拟线性椭圆变分不等式的障碍最优控制问题

对拟线性椭圆变分不等式的障碍最优控制问题(即以障碍为控制变量)进行了研究．指标泛函为Lagrange型,其中含有控制变量二阶导数的p次幂,这使得最优性条件的推导颇为不易．对所考虑的问题给出了最优控制的存在性定理以及必要条件．     

双退化拟线性椭圆型方程Keldys-Fichera障碍问题

讨论一类双退化散度型拟线性椭圆型方程的Keldys-Fichera障碍问题,证明了解的存在性.     

Mathematical Justification of an Obstacle Problem in the Case of a Plate

In this paper the modeling of a thin plate in unilateral contact with a rigid plane is properly justified.Starting from the three-dimensional nonlinear Signorini problem,by an asymptotic approach the convergence of the displacement field as the thickness of the plate goes to zero is studied.It is shown that the transverse mechanical displacement field decouples from the in-plane components and solves an obstacle problem.     

Regularity of a free boundary in parabolic potential theory

We study the regularity of the free boundary in a Stefan-type problem

with no sign assumptions on and the time derivative .

     

Random homogenization of an obstacle problem

We study the homogenization of an obstacle problem in a perforated domain, when the holes are periodically distributed and have random shape and size. The main assumption concerns the capacity of the holes which is assumed to be stationary ergodic.