In this note we give a counterexample to a result of Z.Ditzian and K.Ivanov.A direct theorm on C[0,1]is also presented for Kantorovich operators and Bernstein-Durrmeyer op- erators.
This paper is devoted to study direct and converse approximation theorems of the generalized Bemstein operators Cn （f, sn,x） via so-called unified modulus ωφλ^2 （f,t）, 0 ≤ λ ≤1. We obtain main results as fol...This paper is devoted to study direct and converse approximation theorems of the generalized Bemstein operators Cn （f, sn,x） via so-called unified modulus ωφλ^2 （f,t）, 0 ≤ λ ≤1. We obtain main results as followsωφλ^2 （f,t）=O（t^α）←→｜Cn（f,sn,x）-f（x）｜=O（（n^-1/2δn^1-λ（x））^α）,where δn^2（x）=max{φ^2（x）,1/n} and 0〈α〈2.展开更多
文摘In this note we give a counterexample to a result of Z.Ditzian and K.Ivanov.A direct theorm on C[0,1]is also presented for Kantorovich operators and Bernstein-Durrmeyer op- erators.
基金Supported by the Natural Science Foundation of China (No. 11271263, 11371258)
文摘This paper is devoted to study direct and converse approximation theorems of the generalized Bemstein operators Cn （f, sn,x） via so-called unified modulus ωφλ^2 （f,t）, 0 ≤ λ ≤1. We obtain main results as followsωφλ^2 （f,t）=O（t^α）←→｜Cn（f,sn,x）-f（x）｜=O（（n^-1/2δn^1-λ（x））^α）,where δn^2（x）=max{φ^2（x）,1/n} and 0〈α〈2.
