二阶非线性椭圆型方程组Poincaré问题解的稳定性

本文中,我们讨论二阶非线性椭圆型方程组的一种非正则斜微商边值问题解的稳定性.这个结果主要是利用边值问题解的先验估计来导出的.§1加于椭圆型方程组的条件及问题的适定提法设D是x平面上的N+1(0≤N<∞)连通有界区域,其边界Γ∈C_μ~2(0<μ<1).不失一般性,可以认为D是平面上单位圆内的N+1连通圆界区域,其边界Γ=(?)Γ_j,Γ_j={|z-Z_j|     

K-解析函数的Hilbertert边值问题

定义和讨论了K-解析函数在典型域S~+={z:|z(k)|1}外的K-对称扩张函数,利用它把K-解析函数的Hilbert边值问题转化为Riemann边值问题,得到了K-解析函数类F(D(k))中Hilbert边值问题与Dirichlet边值问题的可解条件及其解的表达式.而解析函数和共轭解析函数都是K-解析函数的特例,所得结果,包含了解析函数和共轭解析函数中的相应结论.     

关于解析函数的一个唯一性定理及其应用

<正> §1.在近代解析函数论中边界值的唯一性定理有许多的研究,其中有我们所习知著名的(?)氏唯一性定理,即:若 D 是某一可求长约当曲线Γ所范围的内域,而 f(z)是 D 内的半纯函数,如在Γ上存在某一测度大于零的集 E_z,对 E_z 任一点 z_0 上,f(z)的角形边界值为零.则必致f(z)≡0于 D 内.同时,卢洵(?)与普里瓦洛夫还指出:存在有单位圆域内非常数的解析函数,而在一个正测度的集(?)上具有等于零的射形边界值.除此之外还有一个很有用的 Koebe 氏定理.即:     

函数域中分圆单位系的独立性

对于分圆函数域k(Λ_M)的每个子域L,本文给出L中分圆单位系的秩公式和独立性的一些等价条件,并决定出具有独立分圆单位系的全部分圆函数域。     

广义解析函数论中的极值原理

1.设G是平面上的有界域,Γ为G的边界,而p>2。依照的定义,所谓u(A,B,G )类的广义解析函数是指复方程的广义正则解。 L.Bers与И.Н.Bexya等人对这种函数类建立了完整的理论,说明了它与解析函数类有许多相同的性质。然而,由于这种函数类的函数相当广泛,所以在一些基本性质上有些u(A,B,G)类与解析函数尚有相当差异。例如,对某些u(A,B,G)类来说,解析函数论中最大模原理     

Koch曲线上的齐次Riemann边值问题

当L为典型的分形曲线一Koch曲线时,提出了Riemann边值问题,但在一般情况下,在Koch曲线上所做的Cauchy型积分无意义.当对已知函数G(z),g(z)增加一定的解析条件,同时利用一列Cauchy型积分的极限函数,对定义在Koch曲线上的齐次Riemann边值问题进行了讨论,并得到与经典解析函数边值问题相类似的结果.     

一类亚解析函数的复合边值问题

本文研究了一类亚解析函数的复合边值问题.利用经典的消去法和对称扩张,得到了边值问题的可解条件和解的表达式.推广了解析函数的相应理论.     

实轴上的双解析函数Riemann边值逆问题

提出了一类实轴上的双解析函数Riemann边值逆问题.先消去参变未知函数,再采用易于推广的矩阵形式记法,可把问题转化为两个实轴上的解析函数Riemann边值问题.利用经典的Riemann边值问题理论,讨论了该问题正则型情况的解法,得到了它的可解性定理.     

双解析函数的Haseman边值问题

本文利用双解析函数的Cauchy型积分和带位移的奇异积分方程方法,研究并得到了双解析函数的Haseman边值问题的一般解的表示式和可解条件以及线性无关解的个数与指标之间的关系.     

广义解析函数的B,H_δ,D,A类函数及其序列的收斂性

本交内容是将B,H_δ,D,A类的单位圆内的解析函数推广到广义解析函数中去,然后将A类函数的唯一性定理,与H_δ类函数有关的黎斯(F.Riesz)定理,与D类函数有关的波卢巴利诺娃一哥齐娜定理应用到广义解析函数中去.由此根据广义解析函数边界值序列在边界上的收敛性研究此类函数在单位圆内部的一致收敛性.将欣金与奥斯特洛夫斯基的定理及都马尔基的定理都应用到广义解析函数中去.     

A.V. Bitsadze's observation on bianalytic functions and the Schwarz problem

According to an observation of A.V. Bitsadze from 1948 the Dirichlet problem for bianalytic functions is ill-posed. A natural boundary condition for the polyanalytic operator, however, is the Schwarz condition. An integral representation for the solutions in the unit disc to the inhomogeneous polyanalytic equation satisfying Schwarz boundary conditions is known. This representation is extended here to any simply connected plane domain having a harmonic Green function. Some other boundary value problems are investigated with some Dirichlet and Neumann conditions illuminating that just the Schwarz problem is a natural boundary condition for the Bitsadze operator.     

Stability of solutions to Hilbert boundary value problem under perturbation of the boundary curve

In this paper, the authors discuss the stability of the solutions to Hilbert boundary value problem under perturbation of the unit circle. When the index of this problem is non-negative, by extending Lavrentjev's conformal mapping on a region approximating to a unit disc, we show the solutions are stable under small perturbations. For negative index we give a conception of quasi-solution and discuss its stability correspondingly.     

Mixed boundary value problems with a shift for a pair of metaanalytic and analytic functions

In this article, we reconsider the mixed boundary value problem on the unit circle for a pair of metaanalytic and analytic functions as in Du and Wang (2008) [9]. By adopting appropriate transformations, we convert the problem into two independent boundary value problems for analytic functions. We then obtain expressions of solution and condition of solvability for the mixed boundary value problem. The forms of the solutions and the condition of solvability here are rather dissimilar to those in Du and Wang (2008) [9]. But the equivalence is established at the end of this article.     

The scalar Nevanlinna-Pick interpolation problem with boundary conditions

We show that if the Nevanlinna-Pick interpolation problem is solvable by a function mapping into a compact subset of the unit disc, then the problem remains solvable with the addition of any number of boundary interpolation conditions, provided the boundary interpolation values have modulus less than unity. We give new, inductive proofs of the Nevanlinna-Pick interpolation problem with any finite number of interpolation points in the interior and on the boundary of the domain of interpolation (the right half plane or unit disc), with function values and any finite number of derivatives specified. Our solutions are analytic on the closure of the domain of interpolation. Our proofs only require a minimum of matrix theory and operator theory. We also give new, straightforward algorithms for obtaining minimal H_∞ norm solutions. Finally, some numerical examples are given.     

A nonlinear elliptic problem with terms concentrating in the boundary

In this paper, we investigate the behavior of a family of steady‐state solutions of a nonlinear reaction diffusion equation when some reaction and potential terms are concentrated in a ε‐neighborhood of a portion Γ of the boundary. We assume that this ε‐neighborhood shrinks to Γ as the small parameter ε goes to zero. Also, we suppose the upper boundary of this ε‐strip presents a highly oscillatory behavior. Our main goal here was to show that this family of solutions converges to the solutions of a limit problem, a nonlinear elliptic equation that captures the oscillatory behavior. Indeed, the reaction term and concentrating potential are transformed into a flux condition and a potential on Γ, which depends on the oscillating neighborhood. Copyright © 2012 John Wiley & Sons, Ltd.     

Generalized third boundary value problem for the biharmonic equation

We study the existence and uniqueness of solutions of a generalized third boundary value problem for the inhomogeneous biharmonic equation in the unit ball.     

The exact number of solutions for the second order nonlinear boundary value problem

A second order nonlinear differential equation with homogeneous Dirichlet boundary conditions is considered. An explicit expression for the root functions for an autonomous nonlinear boundary value problem is obtained using the results of the paper [SOMORA, P.: The lower bound of the number of solutions for the second order nonlinear boundary value problem via the root functions method, Math. Slovaca 57 (2007), 141–156]. Other assumptions are supposed to prove the monotonicity of root functions and to get the exact number of solutions. The existence of infinitely many solutions of the boundary value problem with strong nonlinearity is obtained by the root function method as well. The paper was supported by the Grant VEGA No. 2/7140/27, Bratislava.     

Fourth-order problems with nonlinear boundary conditions

We develop a new method of lower and upper solutions for a fourth-order nonlinear boundary value problem where the differential equation has dependence on all lower-order derivatives. Our boundary conditions are nonlinear. We will assume the functions that define the nonlinear boundary conditions are either monotone or nonmonotone. As a result we obtain existence principles which improve recent results in the literature.