Unique Continuation at the Boundary for Elliptic Operators in Dini Domains

Let u be the solutions to some elliptic equations of the form

Boundary Values of Harmonic Bloch Functions in Lipschitz Domains: A Martingale Approach

In this paper, the boundary behaviour of a certain class of harmonic functions in Lipschitz domains is studied. It continues the work of N. Makarov on the boudary behaviour of analytic Bloch functions in the unit disk. Certain means associated with the function allow to approximate it by a martingale, and the boudary properties of the function are transferred to the asymptotic behaviour of the martingale.     

凸区域上椭圆方程弱解的边界唯一延拓性和B_p权特性

本文研究非光滑凸区域上的散度型二阶椭圆方程 ｉ（ａｉｊ（Ｘ）　ｊｕ（Ｘ））＝０的非零弱解的近边无穷次消失性和双倍性质，刻划弱解梯度在区域边界上的Ｂｐ权特性，建立弱解和弱解的梯度在凸区域边界的任意开子集上不可能同时消失的边界唯一延拓性定理．     

On Domains in Which Harmonic Functions Satisfy Generalized Mean Value Properties

Potential Analysis - Assume that a bounded domain Ω??N (N ≥ 2) has the property that there exists a signed measure µ with compact support in Ω such that, for every...     

Unique Continuation at the Boundary for Harmonic Functions in C1 Domains and Lipschitz Domains with Small Constant

Let be a domain, or more generally, a Lipschitz domain with small local Lipschitz constant. In this paper it is shown that if u is a function harmonic in and continuous in , which vanishes in a relatively open subset ; moreover, the normal derivative vanishes in a subset of with positive surface measure; then u is identically zero. © 2021 The Authors. Communications on Pure and Applied Mathematics published by Wiley Periodicals LLC.     

Unique continuation on a line for the Helmholtz equation

In this article, local unique continuation on a line for solutions of the Helmholtz equation is discussed. The fundamental solution of the exterior problem for the Helmholtz equation have a logarithmic singularity which behaves similar to those of the interior problem for the Laplace equation in two dimension. A Hölder-type conditional stability estimate of the proposed exterior problem for the Helmholtz equation is obtained by adopting the complex extension method in Cheng and Yamamoto [J. Cheng and M. Yamamoto, Unique continuation on a line for harmonic functions, Inverse Probl. 14 (1998), pp. 869–882]. Finally, a regularization scheme based on the collocation method is compatible with the Hölder-type stability estimate provided that the line does not intersect the boundary of the domain for both the Laplace and the Helmholtz equations.     

亚纯函数的唯一性

§ 1.　Introduction　　Inthispaper,unlessspecified ,allthefunctionsarenonconstantmeromorphicfunctions.WeshallusethestandardnotatiosofNevanlinnatheoryofmeromorphicfunctionssuchasT(r,f) ,m(r ,f) ,N(r ,f) , N(r,f) ,… .SetE(r ,f) =∪α∈S{z｜f(z) -a},whereaze ropointwithmultiplicitymiscountedmtimesintheset.AsetSsuchthatforanytwonon constantentirefunctionsf(z)andg(z)theconditionE(S ,f) =E(S ,g)impliesf≡ giscalledauniquerangesetsofentirefunctions.In 1 976,GROSSF [1 ]askedthefollowingquesti…     

无限管状区域上次调和函数的边界性质

作者刻画了定义在无限管状区域中次调和函数的边界性质.通过证明一类新型的Phragmen-Lindelof定理,不仅得到了与之相关最大模极限的存在性定理,而且还得到了其具体的表达式.     

A Note on an Operator-Theoretic Approach to Classic Boundary Value Problems for Harmonic and Analytic Functions in Complex Plane Domains

A general spectral boundary value problems framework is utilized to restate Poincaré, Hilbert, and Riemann problems for harmonic and analytic functions in an abstract operator-theoretic setting.     

Unique Continuation on Quadratic Curves for Harmonic Functions*

The unique continuation on quadratic curves for harmonic functions is discussed in this paper. By using complex extension method, the conditional stability of unique continuation along quadratic curves for harmonic functions is illustrated. The numerical algorithm is provided based on collocation method and Tikhonov regularization.The stability estimates on parabolic and hyperbolic curves for harmonic functions are demonstrated by numerical examples respectively.     

有非负Ricci曲率的度量测度空间上调和函数的边界问题

设(X,d,μ)是满足非负Ricci曲率条件的度量测度空间.本文研究了(开)上半空间X×R+上调和函数的边界问题.我们得到了:若u(x,t)是定义在上半空间X×R+上的调和函数,且满足Carleson测度条件supxB,rB∫rB0fB(xB,rB)|t▽u(x,t)|2dμ(x)dt/t≤C＜∞,其中▽=(▽x,?)...     

Boundary Integrals and Approximations of Harmonic Functions

Steklov expansions for a harmonic function on a rectangle are derived and studied with a view to determining an analog of the mean value theorem for harmonic functions. It is found that the value of a harmonic function at the center of a rectangle is well approximated by the mean value of the function on the boundary plus a very small number (often 3 or fewer) of specific further boundary integrals. These integrals are coefficients in the Steklov representation of the function. Similar approximations are found for the central values of solutions of Robin and Neumann boundary value problems. The results follow from analyses of the explicit expressions for the Steklov eigenvalues and eigenfunctions.     

非均匀调和函数的两类边值问题与积分表达式

本文给出非均匀指数函数的定义及性质,并且进一步引入了非均匀三角函数、非均匀双曲函数和非均匀对数函数.最后利用非均匀指数函数表达形式和非均匀解析函数的Cauchy积分理论,建立了非均匀泊松积分公式和非均匀施瓦茨积分公式,获得了非均匀调和函数在两类特殊边界上的狄利克雷问题和诺伊曼问题解的显示表达式.     

复调和函数及其在无穷远点的性质

本文讨论了复调和函数在无穷远点的性质,揭示出有界区域上复调和函数的两类表示式之间的关系.     

Tangential Boundary Behaviour of Harmonic Functions on Trees

We study the behaviour of harmonic functions on a homogeneous tree from the point of view of the tangential boundary covergence.     

A Note on Bifurcation for Harmonic Maps on Annular Domains

Mediterranean Journal of Mathematics - In this paper we consider harmonic maps u(r, θ) from an annular domain $${Omega _{rho} = B_{1}backslashbar{B}_{rho}}$$ to S 2 with the boundary...     

Strong Unique Continuation of Sub-elliptic Operator on the Heisenberg Group

In this paper, the Almgren’s frequency function of the following sub-elliptic equation with singular potential on the Heisenberg group: $$- \mathcal{L}u + V\left( {z,t} \right)u = - X_i \left( {a_{ij} \left( {z,t} \right)X_j u} \right) + V\left( {z,t} \right)u = 0$$ is introduced. The monotonicity property of the frequency is established and a doubling condition is obtained. Consequently, a quantitative proof of the strong unique continuation property for such equation is given.     

A Note on the Maximal Functions on Weighted Harmonic AN Groups

In this paper, the authors point out that the methods used by Li (2004, 2005, 2007) can be applied to study maximal functions on weighted harmonic AN groups.     

Sets of Harmonicity for Finely Harmonic Functions

Given an open set U in R ⁿ (n3) and a dense open subset V of U, it is shown that there is a finely harmonic function u on U such that V is the largest open subset of U on which u is harmonic. This result, which establishes the sharpness of a theorem of Fuglede, is obtained following a consideration of fine cluster sets of arbitrary functions.     

一类新的单叶调和函数(英文)

A complex-valued harmonic function that is univalent and sense preserving in the unit disk U can be written in the form of f = h + g,where h and g are analytic in U.We define and investigate a new class LH_λ(α,β) by generalized Salagean operator of harmonic univalent functions.We give sufficient coefficient conditions for normalized harmonic functions in the class LH_λ(α,β).These conditions are also shown to be necessary when the coefficients are negative.This leads to distortion bounds and extreme points.