共查询到20条相似文献,搜索用时 156 毫秒
1.
第28届IMO的第四题是一道关于函数方程的试题:求证不存在函数f:N→N,使得对于每个n∈N,f(f(n))=n+1987[1].沈华老师[2]将上述试题推广为下面的定理:定理1设m为自然数,存在函数f:N→N,使得每个n∈N,均有f(f(n))=n+m的充要条件是m为偶数.但其证明有一处小的疏漏(见[2]中证明的(2)式).本文我们首先完善定理1的证明,并给出当m为偶数时满足条件的函数f:N→N的构造与个数.定理1的证明对任何m∈N,假设存在这样的函数f,则有f(n+m)=f(f(f(n))))=f(n)+m.进而由归纳假设易证:对非负整数k,均… 相似文献
2.
3.
4.
本文研究具有无穷维商品空间和不完全金融市场两时期经济的一般均衡存在性问题.假设交易发生在证券以币值单位支付的一系列现货市场和期货市场上,并且对证券的卖空没有任何限制.推广的Stiemke引理是情形的基本估值定理,意即证券价格在时间0的现值是时间1状态集合Ω上收益的价值.一般均衡是一列现货价格和期货价格与一列个体计划,使得市场出清.我们证明一般均衡的存在性,条件是经济人具有Mackey连续、弱凸、严格单调和完全的偏好关系与严格正的初始占有. 相似文献
5.
文[1]用Jensen不等式得到了推广的Holder不等式(即定理1,字母有变),本文用数学归纳法简证并推广. 相似文献
6.
本文讨论了不同分布NA随机变量序列加权和的完全收敛性,获得了较[7]中的定理1及定理A更为一般的安全收敛性,并得到了完全收敛速度与矩条件之间的等价关系。 相似文献
7.
王凤雨 《数学年刊A辑(中文版)》1996,(2)
使用耦合方法,给出SO(n)上椭圆算子第一特征值的一个新下界(定理12),并由此获得格点Yan-Mills场的一个连历定理(定理1.3)最后,将此遍历定理应用于两个具体模型,改进了[2]中相应结果. 相似文献
8.
众所周知:在[a,b]上具有介值性的函数在[a,b]上未必连续.文[1]除举一反例外,还得到了定理:“定理1若函数f(x)在区间[a,b]上有定义,且在[a,b]上具有介值性,则函数f(x)在区间[a,b]上必不存在跳跃间断点.”但这一“定理”不一定成立.请看下例.例1在[0,1]上,分段定义因函数值充满区间[0,1],故函数g(X)具有介值性,但函数是将的线段分别移上移下而得.如图1.照此,不难作出有更多跳跃间断点仍保持介值性的函数.函数是否具有介值性,关键在于:函数值能否填满某个区间,而与函数值的如何分布无关.因此,我们可以仿照狄利克雷… 相似文献
9.
设是En中的有界域,边界充分光滑,满足内切域条件,n是的单位外法向.研究半线性抛物型方程组的初边值问题的解在有限时间内blow-up的问题.设常数a>0,a>-1,β>-1;且aβ>1.ci(x,t)>-0(i=一1,2)关于x,rHlder连续,uo(x)>0,vo(x)且uo(x),vo(x)C1()Bu是u或Bu=且初边值满足相容条件.关于方程组解在有限时间内的blow-up问题,已有不少工作[1-3],本文用特征函数法研究问题(1)-(4)的解在有限时间内blow-up的条件.定理1问题(1)-(4)存在唯一的非负解.证显然V(x,t)=()=(0,0)是问题(1)-(4)的… 相似文献
11.
Kunyang Wang Feng Dai 《分析论及其应用》2007,23(1):50-63
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. 相似文献
12.
H. H. Cuenya M.D. Lorenzo C. N. Rodriguez 《分析论及其应用》2007,23(2):162-170
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. 相似文献
13.
Yuxian Zheng 《分析论及其应用》2006,22(2):136-140
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. 相似文献
14.
15.
《计算数学》2014,(2)
<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 相似文献
16.
《中国科学 数学(英文版)》2014,(8)
<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 相似文献
17.
W.M.Shah A.Liman 《分析论及其应用》2004,20(1):16-27
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. 相似文献
18.
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). 相似文献
19.
A.Al-Shuaibi F.Al-Rawjih 《分析论及其应用》2004,20(1):28-34
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. 相似文献
20.
Francois Chaplais 《分析论及其应用》2006,22(4):301-318
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. 相似文献