共查询到20条相似文献,搜索用时 171 毫秒
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证明了向量值树鞅的若干不等式.主要结果是如下不等式若X同构于q一致凸空间(2≤q<∞),则对每个X值的树鞅f=(ft,t∈T)α≥1和max(α,q)≤β<∞成立‖(S(q)t(f),t∈T)‖
Mα∞≤Cαβ‖f‖ Pαβ‖(σ(p)t(f),t∈T)‖ Mα∞≤Cαβ‖f‖pαβ其中Cαβ是只依赖于α和β的常数. 相似文献
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在允许随机序列上密度无限且减弱权函数是凸函数的条件下,采用新的方法得到C_α中随机指数函数系完备性的充分必要条件,其中C_α是定义在R上的复连续函数构成的加权Banach空间,且要求函数在一致范数下当t→∞时以f(t)exp(-α(t))趋于零. 相似文献
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该文研究了随机函数列{tλn(ω)在加权Banach空间Cα中的完备性与闭包.其中Cα表示在正实轴上连续且满足当,t→ ∞时,|f(t)|e-α(t)→0的连续复函数组成的Banach空间. 相似文献
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设?~k是[0,1]上的CooeB空间,Q:?~k→R是至少具有k-1次代数精度的求积泛函.设J:f|→integral from n=0 to 1 (f(t)dt),h=1/n。通过由等式 M_hf(t)=h sum from i=0 to (n-1)(f(ih+th)),?f∈C[0,1],?t∈[0,1]确定的线性算子M_h:C[0,1]→C[0,1],定义Q的复化求积泛函QM_h。在?~k中的 相似文献
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高进寿 《数学年刊A辑(中文版)》2004,(5)
设B是Cn中的单位球,S是Cn中的单位球面,Sα(f)是B上的面积积分.设f∈BMOA, 若存在正测度集E(?)S,使Sα(f)<∞在E上成立,则Sα(f)<∞在S上几乎处处成立,同时 Sα(f)∈ BMO(S)且存在常数C,使得||Sαf||*≤C||f||*. 相似文献
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关于Szász-Mirakjan算子 总被引:1,自引:0,他引:1
§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 相似文献
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二阶非线性阻尼常微分方程的振动性定理 总被引:14,自引:0,他引:14
考虑二阶非线性阻尼微分方程(α(t)ψ(x(t))x′(t))′ p(t)x′(t) q(t)f(x(t))=0 (1)和二阶非线性微分不等式x(t){(α(t)ψ(x(t))x′(t))′ p(t)x′(t) q(t)f(x(t))}≤0,(2)其中α,p,q∈C([t_0,∞)→(-∞,∞)),ψ,f∈C(R→R),并且α(t)>0,xf(x)>0 (x≠0).此外,我们总假设方程(1)的每一个解 x(t)可以延拓于[t_0, ∞)上.在任何无穷区间[T,∞)上,x(t)不恒等于零,这样的解叫正则解.一个正则解,若它有任意大的零点,则称为振动的;否则就称为非振动的.若方程(1)的所有正则解是振动的,则称方程(1)是振动的.关于不等式(2)的振动性的定义,与方程(1)的振动性的定义完全类似,不再赘述. 相似文献
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宁刚 《数学的实践与认识》2006,36(1):224-226
证明了如下结果:设g∶H→H,C H是非空开的g-凸集,g(C)是凸集,f是C上的上半连续函数且存在α∈(0,1),使得f(αg(x)+(1-α)g(y))m ax{f。g(x),f。g(y)},x,y∈C,则f为C上的g-拟凸函数. 相似文献
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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
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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
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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
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《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
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《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
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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
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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
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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
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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