广义样条及其广义欧拉方程与哈密尔顿特征

1.引言和引理 本文的目的是通过研究超约束变分问题引进一类广义样条函数,并借助广义函数Dirac δ来建立其所满足的广义欧拉微分方程和广义哈密尔顿方程,进而刻画这类广义样条函数的特征性质;特别是利用哈密尔顿函数刻画自由结点样条的特征性质. 熟知,最简单的三次样条函数,就有明显的力学意义和变分性质.因此,经由变分途     

一类广义欧拉函数方程的可解性

将Lehmer同余式从模素数的平方推广到模任意整数的平方,王容、廖群英定义了一类正整数n广义欧拉函数φ_n (5),并给出了准确计算公式,利用已有的广义欧拉函数计算公式,使用初等的方法和技巧,研究了一类广义欧拉函数方程φ₅(n)=n/d的正整数解.     

微分方程的DSOLVE解法

计算机代数系统MAPLE提供的函数dsolve，是求解各类微分方程的重要工具。     

非齐次欧拉方程特解的一种求法

借助实例介绍求非齐次欧拉方程特解的"比较系数法".     

一种包含欧拉函数Ф（n）的方程

设礼和k为任意正整数,Ф（n）是欧拉函数,Ω（n）表示n的所有素因数的个数．本文的主要目的是利用初等方法研究方程Ф（Ф（n）））^k=2^Ω（n）的可解性,同时获得了该方程的所有正整数解．     

KINETIC FLUX VECTOR SPLITTING FOR THE EULER EQUATIONS WITH GENERAL PRESSURE LAWS

This paper attempts to develop kinetic flux vector splitting(KFVS)for the Euler equa-tions with general pressure laws.It is well known that the gas distribution function forthe local equilibrium state plays an important role in the construction of the gas-kineticschemes.To recover the Euler equations with a general equation of state(EOS),a newlocal equilibrium distribution is introduced with two parameters of temperature approx-imation decided uniquely by macroscopic variables.Utilizing the well-known connectionthat the Euler equations of motion are the moments of the Boltzmann equation wheneverthe velocity distribution function is a local equilibrium state,a class of high resolutionMUSCL-type KFVS schemes are presented to approximate the Euler equations of gas dy-namics with a general EOS.The schemes are finally applied to several test problems for ageneral EOS.In comparison with the exact solutions,our schemes give correct location andmore accurate resolution of discontinuities.The extension of our idea to multidimensionalcase is natural.     

一类包含欧拉函数φ（n）的方程

设m,n为任意正整数,φ（n）是欧拉函数.本文的主要目的是利用初等方法研究方程φ（mn）=k（φ（m）＋φ（n））的可解性,其中k为素数,同时获得了该方程的所有正整数解.     

方程φe（n）= nd（e=1,2,4）的可解性

利用已有的广义欧拉函数的准确计算公式来研究方程φe(n)的可解性,其中n为正整数,d为n的正因子.并利用初等的方法和技巧给出方程φe(n)=n/d(e=1,2,4)的全部正整数解(n,d).     

帆船航行最佳路径选取

通过对帆船在海面上航行的受力情况及运动情况简要的分析,在风向保持不变,风速以及浪高满足函数变化时,建立在一定区域内如何逆风航行使得航行时间最少的目标函数,借助拉格朗日函数和欧拉方程,数值求解出最佳航行路线,对帆船运动员在实际操练中有一定指导意义.     

15个著名的不定方程问题

１５个著名的不定方程问题杨仕椿（四川西充县常林中学６３７２００）不定方程的研究，是数论研究中的热点与难点，它以其内容简洁易懂而方法艰深困难向人类的智慧提出挑战．除了著名的Ｆｅｒ－ｍａｔ大定理外，还有许多的其它不定方程问题，本文列举出１５个问题，逐一阐...     

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.