关于Szász-Mirakjan算子

§1 前言设 C={f∶f∈C[0,∞),存在着 N>0,使得 f(x)=O(x~N)(x→ ∞)}.C~r={f;f~(t)∈C.i=0,1,2,…,r}.Szász-Mirakjan 算子是:S_n(,fx)=(?)f(k/n)P_(nk)(x),P_(nk)(x)=e~(-nx)((nx)~k)/(k!),f∈C设 C_0={f:f∈C[0,∞),(?)(?)类似地定义 C_0~r.在[1]中我们曾证明了:对于C_0 中的函数 f,‖S_n(f)-f‖_c=O(k(f,(?)).若0<α<1,则‖S_n(f)-f‖_e=O(n~(-α)与k(f,t)=O(t~(2α))等价。这里 k(f,t)=inf{‖f-g‖_c t~2‖xg〃‖c‖}.不难类似地证明此结     

数学问题解答

2000年4月号问题解答(解答由问题提供人给出)1246.f(n)定义在正整数集合上,且满足f(1)=2,　f(n 1)=(f(n))2-f(n) 1,　n=1,2,3….求证:对所有整数n>1,1-122n-1<1f(1) 1f(2) … 1f(n)<1-122n　　证明　由条件易得　f(n)≥2又∵　f(n 1)=f(n)(f(n)-1) 1　∴　f(n 1)-1=f(n)(f(n)-1)于是　1f(n 1)-1=1f(n)(f(n)-1)=1f(n)-1-1f(n)即　1f(n)=1f(n)-1-1f(n 1)-1所以　∑nk=11f(k)=∑nk=1(1f(k)-1-1f(k 1)-1)=1f(1)-1-1f(n 1)-1=1-1f(n 1)-1下面只要用数学归纳法证明22n-1相似文献   

一个新的数论函数及其均值

设f(n)为任一数论函数,本文的主要目的是引入一类新的可乘函数g f(n),其定义如下:当n=1时,g f(1)=1;对任意素数p及正整数α≥1,定义g f(pα)=pf(α),并给出其均值的两个有趣的渐近公式.     

关于积分Schoenberg样条的一些结果

设T_(n,k)(f)是积分 Schoenberg 样条。设ω_k(f,δ)L~p 是 L~p[0,1]空间中的 k 阶光滑模。定理1 设1≤p≤∝和,f∈L~p[0,1],则‖T_(n(?)k)(f)-f‖_p≤M_p{1/(k+1)ω_1(f,1)L~p+ω_2(f,1/(k+1)~(1/2))_L~p}推论2 设1≤p≤∝和,f∈L~p[0,1],则‖T_(n,k)(f)-f‖_p≤M′_p·ω(?)(f,1/(k+1)~(1/2))_L~p,这儿 M_′p 是仅依赖于 p 的数。推论2给出了 Muller 问题的解(n 固定情况),定理1是 Muller 问题解的推广。我们也推广了关于 Kantorovic 多项式 P_k(f)(T_(1,k)(f)=P_k(f)的 Berens—Devore 定理,Gru-ndmann 定理和 Muller 定理。     

一种神经网络算子及其逼近阶估计

讨论了一种神经网络算子f_n(x)=sum from -n~2 to n~2 (f(k/n))/(n~α)b(n~(1-α)(x-k/n)),对f(x)的逼近误差|f_n(x)-f(x)|的上界在f(x)为连续和N阶连续可导两种情形下分别给出了该网络算子逼近的Jackson型估计.     

一个包含伪Smarandache函数及 Smarandache可乘函数的方程

对任意正整数n,著名的伪Smarandache函数Z(n)定义为最小的正整数m使得n整除m(m 1)/2,或者Z(n)=min{m:m∈N,n│m(m 1)/2},其中N表示所有正整数之集合.而Smarandache可乘函数U(n)定义为U(1)=1,当n1且n=pα11 pα,22…pαss为n的标准素因数分解式时,定义U(n)=max{α1p1,α2p2,…,αsps}.本文的主要目的是利用初等方法研究方程Z(n)=U(n)及Z(n) 1=U(n)的可解性,并获得了这两个方程的所有正整数解.     

Fourier-Laplace级数的强逼近

设f是Rn(n≥3)中单位球面∑n-1上的可积函数,Sθ(f)是步长为θ∈R的平移算子.σδN(f)是Fourier-Laplace级数的δ阶Ceaaro平均.如果∫π0 |Sθ(f)-f|p/θ2dθ∈ L∞ (∑n- 1 ),则∑∞k=0 |σλk(f)-f|p∈L∞(∑n-1)且∑∞k=0(f)-f|p∈L∞(∑n-1 ),其中Eλk(f)为Cesaro平均σλk的等收敛算子.     

非线性微分—差分方程的整函数解

本文考虑了非线性微分—差分方程fn(z)+q(z)eQ(z)f(k)(z+c)=p1eα1z+p2eα2z与fn(z)+q(z)eQ(z)△cf=p1eλz+p2e-λz解的增长性,其中n≥1,k≥1是两个整数,q(z)是非零多项式,Q(z)是非常数多项式.c,λ,α1,α2,p1,p2为非零常数,α1≠α2.特别地,...     

活用两个简单结论巧解两类高考试题

数学中有如下两个人人皆知的简单结论: 　　I 设f(n)=a1+a2+…+an, 　　g(n)=b1+b2+…+bn. 　　若ak=bk(k∈N),则f(n)=g(n). 　　若ak≤bk(k∈N),则f(n)≤g(n). 　　Ⅱ 设f(n)=a1a2…an,g(n)=b1b2…bn. 　　若ak=bk(k∈N),则f(n)=g(n), 　　若ak＞0,bk＞0且ak≤bk(k∈N), 　　则f(n)≤g(n). 　　利用这两个简单结论解答高考试题中与自然数n有关的不(恒)等式的证明问题,思路清晰,通俗易懂.……     

Reinhardt域B_p上正规化双全纯完全准凸映射的齐次展式

本文主要研究C~n中有界凸Reinhardt域B_p上正规化双全纯完全准凸映射的齐次展开式问题,设f(z):B_p→C~n(p＞2)是一个正规化双全纯完全准凸映射,k是满足k＜p≤k+1的自然数,那么f_j(z)=z_j+α_(j2)z_j~2+…+α_(jk)z_j~k+O(|z|~(K+1)),其中f_j是f的第j个分量,j=1,2…．,n．     

ω上非主算术超滤存在性的一个定理

每个非主算术超滤p∈βω-ω都可用来形成一个简单的不可数算术模型Np= {f(p):f∈ωω}N．用这个模型中的超滤(代替自然数)作成的有限分数的等价类便得到所有正实数．用分数表示实数,这正是古希腊人曾有的想法．人们已经知道,Martin 公理的较弱形式MAcountable蕴涵着下面的命题Q: (Q)若B■P(ω)具有sfip(强有限交性质)且|B|<2ω,则存在Q点qB．本文证明命题Q蕴涵着结论:ω上非主算术超滤存在．     

On an identity of Ramanujan

An identity stated and utilized by Ramanujan in his now classic study of certain arithmetical functions is proved.

     

Multiplicative processes on the set of shifted primes

The asymptotical behavior of the distributions of stochastic processes defined by multiplicative functions in the set of shifted primes is considered. The first author was supported by Konferenz der deutschen Akademien der Wissenschaften. Vilnius University, Naugarduko 24, 2006 Vilnius, Lithuania. Paderborn University, Warburger 100, 33098 Paderborn, Germany. Published in Lietuvos Matematikos Rinkinys, Vol. 39, No. 4, pp. 441–460, October–December, 1999.     

Multiplicative processes in short intervals

The asymptotical behavior of the distributions of stochastic processes defined by multiplicative functions in a short interval is considered. Supported by Konferenz der deutschen Akademien der Wissenschaften. Vilnius University, Naugarduko 24, 2006 Vilnius, Lithuania. Paderborn University, Warburger 100, 33098 Paderborn, Germany. Published in Lietuvos Matematikos Rinkinys, Vol. 39, No. 2, pp. 185–199, April–June, 1999.     

Estimation de sommes multiples de fonctions arithmétiques

We estimate some sums of the shape S(X ¹,..., X ^m ):=_{1 d1 X1...1 dm Xm} f(d ₁,..., d _m )when m N and f is a nonnegative arithmetical function. We relate them to the behaviour of the associated Dirichlet series F(s ₁,..., s _m ) = _{d1 = 1} ... _{dm = 1} f(d ₁,..., d _m )/d ₁ ^s1 ... d _m ^sm.The main aim of this work is to develop analytic tools to count the rational points of bounded height on toric varieties.     

On Some Results in Probabilistic Number Theory

The paper presents an overview of main methods and results of the value distribution problem of additive arithmetical functions.     

Derivations and generating degrees in the ring of arithmetical functions

In this paper we study a family of derivations in the ring of arithmetical functions of several variables over an integral domain, and compute the generating degrees of the ring of arithmetical functions over the kernel of these derivations.     

The Turán-Kubilius inequality for additive arithmetical semigroups

We show that the Turán-Kubilius inequality holds for additive arithmetical semigroups satisfying the following conditions: G(n) = q ⁿ (A+O(1/ln n)) (where A > 0 and q > 1) for the number of elements of degree n and P(n) = O(q ⁿ /n) for the number of prime elements of degree n. This is an improvement of a result of Zhang. We also give some variants of the inequality under some stronger or weaker assumptions and applications for the prime divisor function ω and related functions. __________ Translated from Lietuvos Matematikos Rinkinys, Vol. 46, No. 3, pp. 457–471, July–September, 2006.     

由有理数Cauchy列定义的实数的无限十进小数展开

讨论了有理数Cauchy列定义的实数系的一种等价形式———无限十进小数展开,定义了其上的算术运算与顺序并证明了它们和已有的定义一致.     

Isomorphism types of Rogers semilattices for families from different levels of the arithmetical hierarchy

We investigate differences in isomorphism types for Rogers semilattices of computable numberings of families of sets lying in different levels of the arithmetical hierarchy. Supported by RFBR grant No. 05-01-00819 and by INTAS grant No. 00-499. Supported by NSFC grant No. 60310213. __________ Translated from Algebra i Logika, Vol. 45, No. 6, pp. 637–654, November–December, 2006.