某些带变换的边值问题和奇异积分方程

本文主要考虑某些带变换的奇异积分方程。尽管用经典的正则化方法可以求解，我们还是给出一种新的分区跳跃方法，使它们化为较简单的可以系统地求解并可迅即讨论的Ｆｒｅｄｈｏｌｍ积分方程。     

On Fatou Type Convergence of Convolution Type Double Singular Integral Operators

In this paper, some approximation formulae for a class of convolution type double singular integral operators depending on three parameters of the type(T_λf)(x, y) = ∫_a~b ∫_a~b f(t, s)K_λ(t-x,s-y)dsdt, x,y ∈(a,b), λ∈Λ  [0,∞),(0.1)are given. Here f belongs to the function space L_1( a,b ~2), where a,b is an arbitrary interval in R. In this paper three theorems are proved, one for existence of the operator(T_λf)(x, y) and the others for its Fatou-type pointwise convergence to f(x_0, y_0), as(x,y,λ) tends to(x_0, y_0, λ_0). In contrast to previous works, the kernel functions K_λ(u,v)don't have to be 2π-periodic, positive, even and radial. Our results improve and extend some of the previous results of [1, 6, 8, 10, 11, 13] in three dimensional frame and especially the very recent paper [15].     

One-dimensional Singular Integral Equations

A class of singular integral equations having solution in closed form is considered. This class contains the characteristic equation and other equations associated with it. Equations are solved by their reduction to some Riemann boundary value problems in generalized Hölder spaces H_φ (Γ), where Γ is a closed rectifiable Jordan curve for which the Plemelj–Privalov theorem holds.     

On Solvability of a Boundary Value Problem for Singular Integral Equations

This paper deals with the solvability of boundary value problems for singular integral equations of the form (i)-(ii).By an algebraic method we reduce the problem (i)-(ii) to a system of linear algebraic equations which gives all solutions in a closed form.AMS Subject Classification: 47G05, 45GO5, 45E05     

Existence of solutions for dual singular integral equations with convolution kernels in case of non-normal type

This paper is devoted to the study of dual singular integral equations with convolution kernels in the case of non-normal type. Via using the Fourier transforms, we transform such equations into Riemann boundary value problems. To solve the equation, we establish the regularity theory of solvability. The general solutions and the solvable conditions of the equation are obtained. Especially, we investigate the asymptotic property of solutions at nodes. This paper will have a significant meaning for the study of improving and developing complex analysis, integral equations and Riemann boundary value problems.     

Constant-Sign Solutions for Systems of Fredholm and Volterra Integral Equations: The Singular Case

We consider the system of Fredholm integral equations

Constant-Sign Solutions of a System of Fredholm Integral Equations

We consider the following system of Fredholm intergral equations u _i (t)=₀ ¹ g _i (t,s)f _i (s,u ₁(s),u ₂(s),...,u _n (s)) ds, t[0,1], 1in. Criteria are offered for the existence of single, double and multiple solutions of the system that are of constant signs. The generality of the results obtained is illustrated through applications to several well known boundary value problems. We also extend the above system of Fredholm intergral equations to that on the half-line [0,) u _i (t)=₀ g _i (t,s)f _i (s,u ₁(s),u ₂(s),...,u _n (s)) ds, t[0,), 1in and investigate the existence of constant-sign solutions.     

CONVOLUTION EQUATIONS WITH REFLECTION AND TRANSLATION SHIFT

（路见可）ＣＯＮＶＯＬＵＴＩＯＮＥＱＵＡＴＩＯＮＳＷＩＴＨＲＥＦＬＥＣＴＩＯＮＡＮＤＴＲＡＮＳＬＡＴＩＯＮＳＨＩＦＴ￥ＬｕＪｉａｎｋｅ（ＤｅｐｔｏｆＭａｔｈｅｍａｔｉｃｓ，ＷｕｈａｎＵｎｉｖｅｒｓｉｔｙ，Ｗｕｈａｎ４３００７２，Ｃｈｉｎａ）Ａｂｓｔｒ...     

含参数的一类积分方程

根据向量值全纯函数和亚纯函数的理论,由向量值Plemelj公式,讨论一类局部凸空间中具有ζ-函数核的奇异积分方程与边值问题的关系,给出向量值奇异积分方程和边值问题的解及其稳定性.     

直线上带平移的奇异积分方程的解

该文讨论了直线上带实平移或复平移的奇异积分方程的解，获得了方程的可解条件，证明了方程解的唯一性，给出了方程有解的情况下解的积分或级数表达式。     

The solvability of some kinds of singular integral equations of convolution type with variable integral limits

In this paper, we discuss several classes of convolution type singular integral equations with variable integral limits in class $ H^*_1 $. By means of the theory of complex analysis, Fourier analysis and integral transforms, we can transform singular integral equations with variable integral limits into the Riemann boundary value problems with discontinuous coefficients. Under the solvability conditions, the existence and uniqueness of the general solutions can be obtained. Further, we analyze the asymptotic properties of the solutions at the nodes. Our work improves the Noether theory of singular integral equations and boundary value problems, and develops the knowledge architecture of complex analysis.     

Spectrum Problems for Singular Integral Operators with Carleman Shift

In this paper we are concerned with the complete spectral analysis for the operator 𝒯 = 𝒳𝒮𝒰 in the space L_p(𝕋) (𝕋 denoting the unit circle), where 𝒳 is the characteristic function of some arc of 𝕋, 𝒮 is the singular integral operator with Cauchy kernel and 𝒰 is a Carleman shift operator which satisfies the relations 𝒰² = I and 𝒮𝒰 = ±𝒰𝒮, where the sign + or — is taken in dependence on whether 𝒰 is a shift operator on L_p(𝕋) preserving or changing the orientation of 𝕋. This includes the identification of the Fredholm and essential parts of the spectrum of the operator 𝒯, the determination of the defect numbers of 𝒯 — λI, for λ in the Fredholm part of the spectrum, as well as a formula for the resolvent operator.     

含积分算子拟线性系统边值问题的奇摄动

研究奇摄动积分微分方程组边值问题εy"＝f(x,y,Ty,ε)y′++g(x,y,Ty,ε);y(0,ε)＝A(ε),y(1,ε)=B(ε)其中y、g、A和B均为n维向量函数,f是n×n矩阵函数,(Ty)(x)=∫xK(x,s,y(sε),ε)ds在一定假设条件下,利用对角化技巧和逐步逼近法证明解的存在,并给出解的直到0(εN+1)的渐近展开式.     

一类奇异积分和Cauchy型积分关于积分曲线的稳定性

本文讨论了当任意给定的f（τ,t）在某个区域E内属于H类时,奇异积分在封闭或开口光滑曲线E发生光滑扰动时的稳定性,并给出了相应的误差估计．作为应用,我们还讨论了当（t）在E内属于H类时,Cauchy型积分,在封闭光滑曲线E发生光滑扰动时的稳定性及误差估计．     

On solvability of singular integral-differential equations with convolution

In this paper, we study a class of singular integral-different equations of convolution type with Cauchy kernel. By means of the classical boundary value theory, of the theory of Fourier analysis, and of the principle of analytic continuation, we transform the equations into the Riemann-Hilbert problems with discontinuous coefficients and obtain the general solutions and conditions of solvability in class $\{0\}$. Thus, the result in this paper generalizes the classical theory of integral equations and boundary value problems.     

Two classes of linear equations of discrete convolution type with harmonic singular operators

In this paper, we investigate two classes of linear equations of discrete convolution type with harmonic singular operator. Using the Laurent transform theory, we turn the above linear equations into Riemann boundary value problems. Then, the solutions of the equations are obtained in the class of Hölder continuous functions.     

Singular Measures and Convolution Operators

We show that in the study of certain convolution operators, functions can be replaced by measures without changing the size of the constants appearing in weak type （1, 1） inequalities. As an application, we prove that the best constants for the centered Hardy-Littlewood maximal operator associated with parallelotopes do not decrease with the dimension.     

The Dual Singular Function Method for 2D Boundary Integral Equations

The accuracy of standard boundary element methods for elliptic boundary value problems deteriorates if the boundary of the domain contains corners or if the boundary conditions change along the boundary. Here we first investigate the convergence behaviour of standard spline Galerkin approximation on quasi-uniform meshes for boundary integral equations on polygonal domains. It turns out, that the order of convergence depends on some constant describing the singular behaviour of solutions near corner points of the boundary. In order to recover the full order of convergence for the Galerkin approximation we propose the dual singular function method which is often used for improving the accuracy of finite element methods. The theoretical convergence results are confirmed and illustrated by a numerical example.     

含有调和奇异算子的卷积型方程组的解法

讨论了二类离散的含有调和奇异算子的卷积型方程组,并通过离散的Laurent变换,把卷积型方程组化为具有间断系数的解析函数的Riemann边值问题,继而得到方程组的解.