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．     

Cauchy核奇异积分方程关于积分曲线的稳定性

当Ｅ为复平面上的有界连通区域,所有已知函数在Ｅ上满足Ｈｏｌｄｅｒ条件,光滑封闭曲线Г■Ｅ时,借助广义逆,讨论了正则型Ｃａｕｃｈｙ核奇异积分方程在Г发生某种光滑扰动时的稳定性问题,给出了相应的误差估计,并建立了收敛性定理     

开口曲线上的奇异积分近似求积公式

本文利用复插值样函数讨论了开口光滑曲线上的奇异积分在被积函数分别属于 H类和 H* 类时的近似求积公式 ,给出了误差估计和收敛性     

开口弧段上的奇异积分方程关于积分曲线的稳定性

设E是复平面上的有界单连通区域 ,Γ =ab是E中的一条Lyapunov开口弧段 ,当a(z) ,b(z)∈Hv(E) (0 相似文献   

关于曲线积分、曲面积分的定义

关于曲线积分、曲面积分的定义,在现行的教材中多是将其分为第一型(对弧长、对面积)和第二型(对坐标)分别给出的.这种作法在教学中存在着如下两个主要问题:1.由于分别叙述,且内容大体一致,就显得重复繁琐;2.两个定义采取了不同的定义基础(第一型是对光滑曲线、光滑曲面的,第二型是对有向光滑曲线、有向光滑曲面的)”因而无助于对两类曲线积分、曲面积分的联系的理解.针对这种状况,我们采取了如下两个措施:1.两类曲线积分、曲面积分的定义统一给出,节省了叙述的篇幅;2.将两类曲线积分、曲面积分都分别定义在有向光滑曲线、有向光滑曲面上,使定义基础一致,便于对它们的联系的理解.限于篇幅,本文仅就曲线积分进行讨论.     

一道Lebesgue积分题目的注记

设E为n维欧氏空间Rn的可测子集,m E+∞,f(x)为E上的非负可测函数,并记Ek=E{x|k≤f(x)k+1}(k=0,1,2,…),利用Lebesgue积分的性质,通过构造反例,指出"级数∑k km Ek收敛"并不是f(x)在E上Lebesgue可积的充分条件.进一步,通过增加条件"f在E上a.e.有限",得到相应的充分必要条件.     

连续区间上积分值的偶次样条插值

在现实中,某些结点处的函数值往往是未知的,而在连续区间上的积分值是已知的.如何利用连续区间上积分值的信息来解决函数重构是一个重要的问题.文章首先从理论上证明了连续区间上积分值的偶次样条插值的存在唯一性.其次,我们给出了连续区间上积分值的偶次样条插值的光滑性质并且指出四次样条插值是最光滑的.最后,文章给出了偶次样条插值函数去逼近结点处的函数值和偶次高阶导数值时具有超收敛性的猜想.这个猜想在随后的八次样条插值例子中得到证实.     

定积分在高考试题中的应用

一、定义设L为平面上光滑或逐段光滑连续曲线,f(x,y)为定义在L上的函数.对曲线L作分割T.它把L分成n个小段△Li(i=1,2,…,n),以△si记△Li的弧长,分割T的细度     

定积分在高考试题中的应用

一、定义 设L为平面上光滑或逐段光滑连续曲线，f（x，y）为定义在L上的函数．对曲线L作分割T．它把L分成n个小段△Li（i=1，2，…，n），     

一类具一阶奇性核的奇异积分方程

当(?)是复平面C上的光滑封闭曲线,k（z）是在(?)所围成的有界闭区域上连续.在其内部解析的函数时.借助于奇异积分算子的广义逆.讨论了具一阶奇性核的正则型奇异积分方程:　在H类中的求解问题.作为应用,作者给出了当k（z）是一类有理函数时的具体解法,从而统一并推广了 Cauchy核和Hilbert核奇异积分方程的经典结果.     

Queueing systems with inventory management with random lead times and with backordering

We investigate M/M/1/∞-systems with inventory management, continuous review, exponentially distributed lead times and backordering. We compute performance measures and derive optimality conditions under different order policies. For performance measures, which are not explicitly at hand, we present an approximation scheme for all possible parameter combinations. Although we cannot completely determine analytically the steady state probabilities for the system we are able to derive functional relations between interesting probabilities and show surprising insensitivity properties of several performance measures. For the approximations we develop an algorithm adapted to the system structure which suggests easy adaption to other systems.Work supported by Deutscher Akademischer Austauschdienst and KBN, Poland, Project D/02/32206.     

Graphs with unavoidable subgraphs with large degrees

Let ??(n, m) denote the class of simple graphs on n vertices and m edges and let G ∈ ?? (n, m). There are many results in graph theory giving conditions under which G contains certain types of subgraphs, such as cycles of given lengths, complete graphs, etc. For example, Turan's theorem gives a sufficient condition for G to contain a K_{k + 1} in terms of the number of edges in G. In this paper we prove that, for m = αn², α > (k - 1)/2k, G contains a K_{k + 1}, each vertex of which has degree at least f(α)n and determine the best possible f(α). For m = ?n²/4? + 1 we establish that G contains cycles whose vertices have certain minimum degrees. Further, for m = αn², α > 0 we establish that G contains a subgraph H with δ(H) ≥ f(α, n) and determine the best possible value of f(α, n).     

Division with remainder in algebras with valuation

To any integral algebra with valuation an abelian group is associated, which measures how much the uniqueness of the division with remainder is violated. The analogy with the divisor class group is discussed. Examples of such groups are computed in cases of formal local rings of some cusps on an algebraic curve.     

Division with remainder in algebras with valuation

To any integral algebra with valuation an abelian group is associated, which measures how much the uniqueness of the division with remainder is violated. The analogy with the divisor class group is discussed. Examples of such groups are computed in cases of formal local rings of some cusps on an algebraic curve.     

p-Laplacian problems with nonlinearities interacting with the spectrum

The aim of this paper is investigating the existence and the multiplicity of weak solutions of the quasilinear elliptic problem $$\left\{\begin{array}{ll}-\Delta_p u\ =\ g(x, u) \quad {\rm in} \quad \Omega,\\ u=0 \qquad \qquad \qquad {\rm on}\quad \partial\Omega,\end{array}\right.$$ where ${1 < p < + \infty, \Delta_p u = {\rm div}(|\nabla {u}|^{p-2}\nabla {u})}$ , Ω is an open bounded domain of ${\mathbb{R}^N (N \geq 3)}$ with smooth boundary ?Ω and the nonlinearity g behaves as u ^p?1 at infinity. The main tools of the proof are some abstract critical point theorems in Bartolo et al. (Nonlinear Anal. 7: 981–1012, 1983), but extended to Banach spaces, and two sequences of quasi–eigenvalues for the p–Laplacian operator as in Candela and Palmieri (Calc. Var. 34: 495–530, 2009), Li and Zhou (J. Lond. Math. Soc. 65: 123–138, 2002).     

Problem with Critical Sobolev Exponent and with Weight

The authors consider the problem: -div(p▽u) = uq-1 λu, u > 0 inΩ, u = 0 on (?)Ω, whereΩis a bounded domain in Rn, n≥3, p :Ω→R is a given positive weight such that p∈H1 (Ω)∩C(Ω),λis a real constant and q = 2n/n-2, and study the effect of the behavior of p near its minima and the impact of the geometry of domain on the existence of solutions for the above problem.     

Integro-differential operators associated with diffusion processes with jumps

We show existence andW _loc ^2,p W^1,-regularity results for the integro-differential equation, associated with a diffusion process with jumps on a bounded domain. The second order elliptic partial differential operator and the integral operator involved here are both maximum principle type operators, which enables us to makeW ^1, a priori estimates.     

Orthogonality Associated with Bessel-Type Sheffer Sequences with Q-Parameters

Mathematical Notes - Certain orthogonal polynomials are involved in various problems occurring in probability, celestial mechanics, combinatorics, and other fields of theoretical and applied...