Hammerstein型弱奇异积分方程的β-多项式配置方法

1．引言对VOlterra弱奇异积分方程和积一微分方程之配置方法已有不少文章讨论［1－6］．由于其解在左端点处的非光滑性[3]并要得到m-1次多项式配置解的最优收敛率。，需采用所谓的等级网格．早期M作［1,2］是将等级指数r取为1，a表征核（t—s）ak（t，8）的奇异程度），但...     

多滞量积分方程基于高阶插值的分步配置方法

1．引言考虑多滞量Volterra积分方程其中常数假定已知函数R在定义域内连续，以保证方程（1.1）存在唯一解形如（1．1）的Volterra延滞积分方程常出现在物理问题和生物模型中［2］．由于“滞量”的影响，对其作理论分析和数值研究均比“古典”的Volterra积分方程更为困难．近来人们对Volterra延滞积分方程的数值求解越来越感兴趣[3，4]，但目前的工作基本上只限于单滞量的情形：并采用所谓的“约束”网格（即要求步长人整除一，且假定T是，的整数倍（否则，应在更大的区间上求解），以保证数值解在结点集上具有理想的收敛率．显然，这些限…     

解第一类边界积分方程的高精度机械求积法与外推

０．引言使用单层位势理论把Ｄｉｒｉｃｈｌｅｔ问题：转化为具有对数核的边界积分方程：这里Г假设为简单光滑闭曲线．熟知,若Г的容度Ｃｒ≠１,（０．２）有唯一解存在［１］．借助参数变换这里的数值解法有Ｇａｌｅｒｋｉｎ法［２］,配置法［３］,和谱方法~［４］,这些方法有一个共同缺点就是矩阵元素的生成要计算反常积分,由于离散方程的系数矩阵是满阵,使矩阵生成的工作量很庞大,甚至超过了解方程组的工作量．显然,如能找到适当求积公式离散（０．２）,则可节省大量计算．使用求积公式法解（０．２）的文献不多,［５］中提…     

非线性积分方程在权空间(R~n,w(t))的唯一可解性(英)

本文对于一般的Fredholm积分方程组，在权空间｛R~n，C[I，w（t）]｝内给出了更一般的存在唯一性定理，如果方程是Volterra型积分方程，便得了解存在唯一的更弱条件，推广和改进了已有结果，且把这些结果推广到权空间｛R~n，L~p[I，(t）]｝．最后研究了第一类积分方程的可解性．     

非线性Volterra积分方程解强收敛和弱收敛的充要条件

本文研究Ｂａｎａｃｈ空间中具完全正核的非线性Ｖｏｌｔｅｒｒａ积分方程解强收敛和弱收敛的充分必要条件，这里的定理推广了众多该方向的结果，例如［５，９－１０］等．     

解高维广义对称正则长波方程的Fourier谱方法

１引言对称正则长波方程（ＳＲＬＷＥ）是正则化长波方程（ＲＬＷＥ）的一种对称叙述［１］用于描述弱非线性作用下空间变换的离子声波传播．［１］得到了方程组（１．１）的双曲正割平方孤立波解、四个不变量和数值结果、明显地,从（１．１）中消去ρ,得到一类正则长波方程（ＲＬＷＥ）代替（１．２）中第三项、第四项对ｔ的导数为对ｘ的导数,得到Ｂｏｕｓｓｉｎｅｓｑ方程．［２］对一类广义对称正则长波方程组提出了谱方法,证明了古典光滑解的存在性和唯一性,建立了近似解的收敛性和误差估计。［３］研究了高维对称正则长波方程整体…     

W2^2（D）空间第一类算子方程近似解

０引言本文在具有再生核的Ｓｏｂｏｌｅｖ空间Ｗ＿２~２（Ｄ）中研究第一类算子方程的近似求解问题,本文利用再生核空间技巧得到的方程（１）的近似解ｕｎ（Ｍ）有如下特点：１近似解ｕｎ（Ｍ）的构成只需用到ｆ在有限个节点｛Ｗｉ｝１ｎ　Ｄ上的值;２当｛Ｍｉ｝１在Ｄ中稠密时,可以得到方程解析解ｕ（Ｍ）的表达式,并且而且误差随节点个数ｎ的增加接空间范数单调下降．数值算例表明,该方法是有效的．1Ｗ22（Ｄ）空间及其再生核记Ｄ=［ａ,ｂ］×［ｃ,ｄ］为有限区域,设是Ｄ上一组互异节点系．在［１］中,设Ｗ２２［ａ,ｂ］＝｛ｕ…     

一类奇异积分—微分方程的直接解法

对于系数、核密度具某种解析性的Ｃａｕｃｈｙ核完全奇积分方程，文［１］、［２］研究了其直接求解方法，［３］采用［１］，［２］中的思想方法，研究了如下形式的奇异积分一微分方程ａ１（ｔ）ψ（ｔ）＋ａ２（ｔ）ψ＇（ｔ）＋１／πｉ∫Ｌｋ１（ｔ，τ）／τ－ｔψ（τ）ｄτ＋１／πｉ∫Ｌｋ２（ｔ，τ）／τ－ｔψ＇（τ）ｄτ＝ｆ（ｔ），ｔ包含Ｌ的直接解法，其中Ｌ是平面上的一封闭光滑曲线，并对系数和核密度给出了一系列     

第二类弱奇异边界积分方程配置解的外推与超收敛

本文证明具有弱奇异核的第二类边界积分方程的线元配置解可以通过处推法提高精度,证明常元配置解内点有超收敛估计,这些结果对较困难的三维问题电予以讨论。     

一类奇异积分－微分方程的直接解法

一类奇异积分－微分方程的直接解法黄小玲（中山大学）对于系数、核密度具某种解析性的Ｃａｕｃｈｙ核完全奇异积分方程，文［１］、［２］研究了其直接求解方法。［３］采用［１］、［２］中的思想方法，研究了如下形式的奇异积分－微分方程的直接解法，其中Ｌ是平面上的...     

Collocation Methods and Their Modifications for Cauchy Singular Integral Equations on the Interval

In this paper we present polynomial collocation methods and their modi.cations for the numerical solution of Cauchy singular integral equations over the interval [-1, 1]. More precisely, the operators of the integral equations have the form with piecewise continuous coefficients a and b, and with a Jacobi weight . Using the splitting property of the singular values of the collocation methods, we obtain enough stable approximate methods to .nd the least square solution of our integral equation. Moreover, the modifications of the collocation methods enable us to compute kernel and cokernel dimensions of operators from a C*-algebra, which is generated by operators of the Cauchy singular integral equations.     

Superconvergence results of iterated projection methods for linear Volterra integral equations of second kind

In this paper, we develop the iteration techniques for Galerkin and collocation methods for linear Volterra integral equations of the second kind with a smooth kernel, using piecewise constant functions. We prove that the convergence rates for every step of iteration improve by order \({\mathcal {O}}(h^{2})\) for Galerkin method, whereas in collocation method, it is improved by \({\mathcal {O}}(h)\) in infinity norm. We also show that the system to be inverted remains same for every iteration as in the original projection methods. We illustrate our results by numerical examples.     

Collocation and iterated collocation methods for a class of weakly singular Volterra integral equations

We discuss the convergence properties of spline collocation and iterated collocation methods for a weakly singular Volterra integral equation associated with certain heat conduction problems. This work completes the previous studies of numerical methods for this type of equations with noncompact kernel. In particular, a global convergence result is obtained and it is shown that discrete superconvergence can be achieved with the iterated collocation if the exact solution belongs to some appropriate spaces. Some numerical examples illustrate the theoretical results.     

Piecewise Polynomial Collocation for Volterra-type Integral Equations of the Second Kind

The exact solution of a given integral equation of the secondkind of Volterra type(with regular or weakly singular kernel)is projected into the space of (continuous) piecewise polynomialsof degree m 1 and with prescribed knots by using collocationtechniques. It is shown that a number of discrete methods forthe numerical solution of such equations based on product integrationtechniques or on finite-difference methods are particular discreteversions of collocation methods of the above type. The errorbehaviour of approximate solutions obtained by collocation (includingtheir discretizations) is discussed.     

On the uniform convergence of a collocation method for a class of singular integral equations

We establish the uniform convergence of a collocation method for solving a class of singular integral equations. This method uses the Jacobi polynomials {P _n ^{(, )} } as basis elements and the zeros of a Chebyshev polynomial of the first kind as collocation points. Uniform convergence is shown to hold under the weak assumption that the kernel and the right-hand side are Hölder-continous functions. Convergence rates are also given.     

Blowing up behavior for a class of nonlinear VIEs connected with parabolic PDEs

We study the blowing-up behavior of solutions of a class of nonlinear integral equations of Volterra type that is connected with parabolic partial differential equations with concentrated nonlinearities. We present some analytic results and, in the case of the kernel of Abel-kind with power nonlinearity and fixed initial data, we give a numerical approximation by using one-point collocation methods.     

Full collocation methods for some boundary integral equations

In this paper we propose a fully discretized version of the collocation method applied to integral equations of the first kind with logarithmic kernel. After a stability and convergence analysis is given, we prove the existence of an asymptotic expansion of the error, which justifies the use of Richardson extrapolation. We further show how these expansions can be translated to a new expansion of potentials calculated with the numerical solution of a boundary integral equation such as those treated before. Some numerical experiments, confirming our theoretical results, are given. This revised version was published online in August 2006 with corrections to the Cover Date.     

Numerical solution of nonlinear two-dimensional Fredholm integral equations of the second kind using Gauss product quadrature rules

The Gauss product quadrature rules and collocation method are applied to reduce the second-kind nonlinear two-dimensional Fredholm integral equations (FIE) to a nonlinear system of equations. The convergence of the proposed numerical method is proved under certain conditions on the kernel of the integral equation. An iterative method for approximating the solution of the obtained nonlinear system is provided and its convergence is proved. Also, some numerical examples are presented to show the efficiency and accuracy of the proposed method.     

Midpoint collocation for Cauchy singular integral equations

Summary A Cauchy singular integral equation on a smooth closed curve may be solved numerically using continuous piecewise linear functions and collocation at the midpoints of the underlying grid. Even if the grid is non-uniform, suboptimal rates of convergence are proved using a discrete maximum principle for a modified form of the collocation equations. The same techniques prove negative norm estimates when midpoint collocation is used to determine piecewise constant approximations to the solution of first kind equations with the logarithmic potential.This work was supported by the Australian Research Council through the program grant Numerical analysis for integrals, integral equations and boundary value problems     

Superconvergence of numerical solutions to weakly singular Volterra integro-differential equations

Summary We discuss the application of a class of spline collocation methods to first-order Volterra integro-differential equations (VIDEs) which contain a weakly singular kernel (t–s)^– with 0<<1. It will be shown that superconvergence properties may be obtained by using appropriate collocation parameters and graded meshes. The grading exponents of graded meshes used are not greater thanm (the polynomial degree) which is independent of . This is in contrast to the theories of spline collocation methods for Volterra (or Fredholm) integral equation of the second kind. Numerical examples are given to illustrate the theoretical results.