运用凸函数的Jensen不等式、K-泛函和Hardy-Littlewood极大函数等工具,研究了Bernstein-Durrmeyer多项式在Orlicz空间内的逼近性质,建立了逼近正逆定理.
In this paper,the approximation properties of Bernstein-Durrmeyer polynomial in Orlicz spaces was studied by using the Jensen inequality of convex function,K-functional and Hardy-Littlewood extremal large function,and establish the direct and inverse approximation theorems.