模糊值函数的曲线积分

针对扩张原理在模糊值函数曲线积分中的遍历性问题,根据模糊结构元理论给出了第一型模糊值函数曲线积分的定义.然后通过讨论平面模糊矢量的投影问题,给出了第二型模糊值函数曲线积分定义并对其相关性质进行了讨论.研究结果不仅丰富了模糊分析学理论,而且为具有不确定性因素的工程实践提供了方法依据.     

封闭曲线上的奇异积分方程的样条间接逼近解法

利用复插值样条函数，给出了定义于光滑封闭曲线上一般的正则型奇异积分方程的样条间接逼近解法，证明了一致收敛性．对于其中的一类奇异积分方程，还给出了近似解和误差估计．     

区间值函数与模糊值函数的无穷积分

[1]中推广了区间值函数积分的定义,建立了Fuzzy值函数积分的概念。本文正是在此基础上给出了无穷区间上区间值函数和Fuzzy值函数的定义,进一步给出了它们的积分的定义,以及积分收敛的性质定理和判定定理。     

对称性在重积分及曲面积分中的应用

在积分区域具有某种对称性时,给出重积分及曲面积分所具有的相应性质,并通过例题给出这些性质在重积分及曲线、曲面积分中的应用方法.     

α次导数与Cauchy型积分

定义Laplace变换的像函数的任意实数次导数,同时给出了α次导数的性质,并建立了它和复围道积分的联系,给出了一类Cauchy型积分的计算公式.     

再生核空间W_2~2(*)中积分-微分方程精确解的表示

该文定义了一个再生核空间W_2~2(*),在其中讨论了积分-微分方程解的存在唯一性,给出了积分-微分方程一个定解问题的精确解的表达式及由精确解得出近似解的性质.     

AP积分与Gronwall不等式

ＡＰ积分与Ｇｒｏｎｗａｌｌ不等式王才士（西北师范大学计算机系，兰州７３００７０）设表示实直线Ｒ上的密度拓扑（见［２］）．点ｘ∈Ｒ在密度拓扑下的邻域系记为定义称函数ｆ在［ａ，ｂ］上满足Ａ－Ｎ条件，如果对任何非空零测集及任意ε＞０，存在的一个选择使得对［...     

由环的P-性质所确定的根

定义了环的Ｐ根Ｐ、弱拟Ｐ根Ｐｗ 和拟Ｐ根ＰＱ,证明它们均为Ａｍ ｉｔｓｕｒＫｕｒｏｓｈ 根且Ｐ＝ Ｐｗ 为特殊根,给出了Ｐ半单环的结构定理和Ｐ根的模刻划     

一类奇异积分方程组的样条间接近似解法

本文利用三次复插值样条函数给了定义于复平面上光滑封闭曲线上的一类奇异积分方程组（１）的一种间接近似解法，讨论了误差估计和一致收敛性。     

Said型广义Ball基函数的拓展

在本文中,我们给出了构造Said型广义Ball基函数的新方法,该方法的优点在于,既可以推出奇次多项式的Said型广义Ball基函数表示,也可以推出偶次多项式的Said型广义Ball基函数表示;该方法的另一优点是,能很自然地定义Said型广义Ball基函数的对偶泛函; 给出了Said型广义Ball基函数的积分性质;定义了一种新的基函数, Said型广义Ball基函数是其特例; 给出了这种新的基函数的对偶泛函和类Marsden恒等式.     

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.     

Consistent first-return Riemann sums for Lebesgue integrals

U. B. Darji and M. J. Evans [1] showed previously that it is possible to obtain the integral of a Lebesgue integrable function on the interval [0,1] via a Riemann type process, where one chooses the selected point in each partition interval using a first-return algorithm based on a sequence {x _n} which is dense in [0,1]. Here we show that if the same is true for every rearrangement of {x _n}, then the function must be equal almost everywhere to a Riemann integrable function. This revised version was published online in June 2006 with corrections to the Cover Date.     

The Non-uniform Riemann Approach to Anticipating Stochastic Integrals

Abstract

In this note, we use the Riemann approach to give alternative definition to the anticipating stochastic integral. However non-uniform meshes instead of uniform meshes are used in the Riemann sums.     

Approximate approximations from scattered data

The aim of this paper is to extend the approximate quasi-interpolation on a uniform grid by dilated shifts of a smooth and rapidly decaying function to scattered data quasi-interpolation. It is shown that high order approximation of smooth functions up to some prescribed accuracy is possible, if the basis functions, which are centered at the scattered nodes, are multiplied by suitable polynomials such that their sum is an approximate partition of unity. For Gaussian functions we propose a method to construct the approximate partition of unity and describe an application of the new quasi-interpolation approach to the cubature of multi-dimensional integral operators.     

黎曼相关积分研究

通过证明和反例讨论黎曼积分、直接黎曼积分、黎曼-斯蒂尔切斯积分三者间的联系与区别.结果显示：若函数直接黎曼可积,则它黎曼可积,并且两者积分值相同,但反之不成立;若函数黎曼可积,则任意连续函数关于该函数不一定黎曼-斯蒂尔切斯可积.从讨论结果中还获得直接黎曼可积和黎曼可积各自的一个充分条件.     

On the Henstock-Kurzweil Integral for Riesz-Space-Valued Functions Defined on Unbounded Intervals

In this paper we introduce and investigate a Henstock-Kurzweil-type integral for Riesz-space-valued functions defined on (not necessarily bounded) subintervals of the extended real line. We prove some basic properties, among them the fact that our integral contains under suitable hypothesis the generalized Riemann integral and that every simple function which vanishes outside of a set of finite Lebesgue measure is integrable according to our definition, and in this case our integral coincides with the usual one.     

Representation of the Stieltjes Integral in Terms of the Riemann Integral Depending on a Parameter

In this paper, we obtain a new formula for the representation of the Riemann-Stieltjes integral of a continuous function in terms of the passage to the limit with respect to the parameter in a Riemann integral depending on this parameter. The derivation of this formula is based on the study of the functional properties of the solution of the auxiliary difference equation of first order representing the weighted first difference of a given function in the form of a simple first difference of an unknown function. The result obtained can be used for the analytic and approximate calculation of Stieltjes integrals.     

了解积分——求和

求一个函数的黎曼积分,实际上就是一个分割、近似代替、求和、取极限的过程.求和运算是整个积分计算的轴心.就积分四部曲中的求和问题,做一个一般性的讨论.文中使用的是分析和讨论的语言,不去追求数学语言本身的严格性.目的不仅是探讨求和这个步骤,在黎曼积分意义下具体实现的过程和隐含的内容,而且对一般的积分中的求和实现的可能性、应该满足的条件、实现的过程,以及应该注意那些基本问题,也做一点儿逻辑上的探讨.已达到以知识为媒介,提高认知能力的目的.     

用正交函数求超奇异积分的近似值及其误差估计

基于 Hadamard有限部分积分定义, 当密度函数是多项式、正弦函数和余弦函数时, 本文推导出了计算超奇异积分准确值的公式, 进而利用这些公式给出了密度函数为一般连续函数的超奇异积分近似值的计算方法. 本文还对近似值进行了误差分析, 据此可以在事先给定的误差下来计算超奇异积分的近似值. 最后将前面的理论应用到超奇异积分方程求近似解的问题. 数值算例表明该方法的可行性和有效性.     

On the Strong McShane Integral of Functions with Values in a Banach Space

The classical Bochner integral is compared with the McShane concept of integration based on Riemann type integral sums. It turns out that the Bochner integrable functions form a proper subclass of the set of functions which are McShane integrable provided the Banach space to which the values of functions belong is infinite-dimensional. The Bochner integrable functions are characterized by using gauge techniques. The situation is different in the case of finite-dimensional valued vector functions.