Copositive approximation by rational functions with prescribed numerator degree

被引：0

作者：

YU Dan-sheng1 ZHOU Song-ping21 Department of Mathematics

Department of Mathematics

机构：

来源：

Applied Mathematics:A Journal of Chinese Universities | 2009年 / 04期

基金：

中国国家自然科学基金;

关键词：

copositive approximation; rational functions; approximation rate;

D O I：

暂无

中图分类号：

O174.41 [逼近论];

学科分类号：

070104 ;

摘要：

The paper proves that,if f(x)∈Lp[-1,1 ≤ p < ∞,changes sign l times in(-1,1),-1,1] then there exists a real rational function r(x) ∈ Rn(2μ-1)l which is copositive with f(x),such that the following Jackson type estimate ‖f-r‖p≤Cδl2μω holds,where μ is a natural nuωmber ≥(3/2)+(1/p),and Cδ is a positive constant depending only on δ.

引用

页码：411 / 416

页数：6