Clifford 分析中无界域上正则函数带Haseman位移的边值问题

该文在引入修正的Cauchy核的基础上,讨论了Clifford 分析中无界域上正则函数带 Haseman 位移的边值问题. 首先给出了无界域上Cauchy 型积分的Plemelj公式,再利用积分方程方法和压缩不动点定理证明了问题解的存在唯一性.     

四元数分析中无界域上正则函数的带位移非线性边值问题

讨论了四元数分析中无界域上正则函数的一类带位移非线性边值问题.利用积分方程方法和Schauder不动点理论证明了问题解的存在性,并给出了解的积分表达式.     

Bochner-Martinelli型积分的边界性质

对 Cn中具光滑边界Ω的有界域 D和属于指数α( 0 <α <1 )的 Lipschitz空间 Lip(α,Ω )中的每个函数φ,我们不仅证明了 Bochner- Martinelli型积分Φ ( z) =∫Ωφ(ζ) K(ζ,z)(其中 K(ζ,z)为 Bochner- Martinelli型积分核 )表示的内、外极限值Φ +( t) ,Φ - ( t)属于 Lip(β,Ω ) ( 0 <β <α <1 )而且可分别延拓成 D和 Dc上的指数为β的 Holder连续函数 ,并由此给出了 Bochner- Martinelli变换的 Plemelj跳跃公式 .     

具有无界非线性项的广义逐段常变量微分方程拓扑等价函数的正则性

关于微分方程的拓扑等价以及拓扑等价函数的正则性一直是微分方程研究的焦点之一.当非线性项有界时,已经有很多学者证明了微分方程的拓扑等价函数是H?lder正则的.然而,当非线性项无界时,拓扑等价的正则性尚无突破性结果.在无界情形下, Zou和Shi(2017)得到了拓扑线性化的条件.除Zou和Shi(2017)给出的条件外,在附加的一个前提下,本文证明拓扑等价函数的H?lder正则性.事实上,当系统是有界时,系统线性化的条件足以保证其H?lder正则性.但是,当系统是无界时,这个附加条件是必不可少的.本文举例说明这个事实.这是首篇考虑无界系统拓扑等价H?lder正则的文章.     

仿射自同构群和小波变换

令D(Φ,Ω)是第一类典型域的无界实现.它的     

动力系统方法解决无界线性算子方程

针对反问题中出现的第一类算子方程Au=f,其中A是实Hilbert空间H上的一个无界线性算子利用动力系统方法和正则化方法,求解上述问题的正则化问题的解:u'(t)=-A~*(Au(t)-f)利用线性算子半群理论可以得到上述正则化问题的解的半群表示,并证明了当t→∞时,所得的正则化解收敛于原问题的解.     

Clifford分析中无界域上Isotonic函数的Plemelj公式

定义了无界域上Isotonic函数的Cauchy型积分和Cauchy主值积分,考虑了其边界性质,得到了无界域上Isotonic函数的Plemelj公式.     

有界多连通区域数值保角变换的GMRES(m)法北大核心CSCD

求解复杂多连通区域的保角变换函数是困难的.针对这一问题,该文将求解保角变换函数转化为利用模拟电荷法求解一对定义在问题区域上的共轭调和函数,再根据边界条件建立约束方程,并利用GMRES(m)(the generalized minimal residual method)算法求解约束方程,获得了模拟电荷,进而构造了高精度的近似保角变换函数,将有界多连通区域映射为三种无界正则狭缝域.数值实验验证了该文算法的有效性.     

关于域的K_2群的挠

设F是域,记G_n(F)={{a,Φ_n(a))∈K_2(F)|a,Φ_n(a)∈F_~*},这里Φ_n(x)是n次分圆多项式.首先,使用关于数域上的Mordell猜想的Faltings定理证明了若F是数域,n≠1,4,8,12且含有平方因子,则G_n(F)不是K_2(F)的子群;然后,使用Manin,Grauert,Samuel和李克正关于函数域上的Mordell猜想的结果,对代数闭域上的函数域证明了类似的结果.     

PM-空间中扩张型映象的不动点定理

本文中处处假设(E,(?),Δ)是(?)完备的 Menger 空间,t-范数Δ满足(?)Δ(t,t)=1。定义1 设Φ(t)是[0,∞)上的函数,我们称Φ(t)满足条件(Φ_1),如果Φ(t)不减、Φ(0)=0,且(?)Φ~n(t)=∞,(?)t>0;称Φ(t)满足条件(Φ_2),如果Φ(t)严格增、左连续、Φ(0)=0,且(?)Φ~n(t)=∞,(?)t>0,其中Φ~n(t)是Φ(t)的第 n 次迭代。     

RECENT PROGRESS ON SPHERICAL HARMONIC APPROXIMATION MADE BY BNU RESEARCH GROUP ——In memory of Professor Sun Yongsheng

As early as in 1990, Professor Sun Yongsheng, suggested his students at Beijing Normal University to consider research problems on the unit sphere. Under his guidance and encouragement his students started the research on spherical harmonic analysis and approximation. In this paper, we incompletely introduce the main achievements in this area obtained by our group and relative researchers during recent 5 years （2001-2005）. The main topics are： convergence of Cesaro summability, a.e. and strong summability of Fourier-Laplace series; smoothness and K-functionals; Kolmogorov and linear widths.     

A unified approach to certain problems of best local approximation

In this paper we study best local quasi-rational approximation and best local approximation from finite dimensional subspaces of vectorial functions of several variables. Our approach extends and unifies several problems concerning best local multi-point approximation in different norms.     

Boundedness for commutators of multipliers on Hardy type spaces

In this paper, we study the commutators generalized by multipliers and a BMO function. Under some assumptions, we establish its boundedness properties from certain atomic Hardy space Hb^p（R^n） into the Lebesgue space L^p with p 〈 1.     

THE 8~(th) INTERNATIONAL CONGRESS ON INDUSTRIAL AND APPLIED MATHEMATICS

<正>August 10-14,2015Beijing,ChinaThe International Congress on Industrial and Applied Mathematics(ICIAM)is the premier international congress in the field of applied mathematics held every four years under the auspices of the International Council for Industrial and Applied Mathematics.From August 10 to 14,2015,mathematicians,scientists     

Towards Excellence in Science Chinese Academy of Sciences

<正>May 26,2014,Beijing Science is a human enterprise in the pursuit of knowledge.The scientific revolution that occurred in the 17th Century initiated the advances of modern science.The scientific knowledge system created by     

Bounds for the zeros of polynomials

Let P(z)=∑↓j=0↑n ajx^j be a polynomial of degree n. In this paper we prove a more general result which interalia improves upon the bounds of a class of polynomials. We also prove a result which includes some extensions and generalizations of Enestrǒm-Kakeya theorem.     

Boundedness of commutators related to Marcinkiewicz integrals on hardy type spaces

In this paper, the authors study the boundedness of the operator [μΩ, b], the commutator generated by a function b ∈ Lipβ(Rn)(0 ＜β≤ 1) and the Marcinkiewicz integrals μΩ, on the classical Hardy spaces and the Herz-type Hardy spaces in the case Ω∈ Lipα(Sn-1)(0 ＜α≤ 1).     

Jacobi polynomials used to invert the laplace transform

Given the Laplace transform F(s) of a function f(t), we develop a new algorithm to find an approximation to f(t) by the use of the classical Jacobi polynomials. The main contribution of our work is the development of a new and very effective method to determine the coefficients in the finite series expansion that approximation f(t) in terms of Jacobi polynomials. Some numerical examples are illustrated.     

Generalization of the interaction between Haar approximation and polynomial operators to higher order methods

In applications it is useful to compute the local average empirical statistics on u. A very simple relation exists when of a function f（u） of an input u from the local averages are given by a Haar approximation. The question is to know if it holds for higher order approximation methods. To do so, it is necessary to use approximate product operators defined over linear approximation spaces. These products are characterized by a Strang and Fix like condition. An explicit construction of these product operators is exhibited for piecewise polynomial functions, using Hermite interpolation. The averaging relation which holds for the Haar approximation is then recovered when the product is defined by a two point Hermite interpolation.