Beta算子收敛速度的下界估计

Lower estimates of convergence rate for Beta operators

线性算子收敛速度的下界估计是一个比较困难的问题，文章将近年来Ｚ．Ｄｉｔｚｉａｎ，Ｋ．Ｇ．Ｉｖａｎｏｖ 等人在建立强逆不等式过程中所创造的一系列方法综合地应用于估计Ｂｅｔａ 算子收敛速度的下界，得到了新的、较好的结果．

The lower estimate of convergence rate of linear operators is a more difficult problem, a series of methods which created by Z. Ditzian and K.G. Ivanov et al in establishing strong converse inequaties in recent years are applied to lower estimate of convergence rate for Beta operators synthesisly in this paper, a new and better result is obtained.