A characterization of weighted approximations by the Post-Widder and the Gamma operators, II

摘要

We present a characterization of the approximation errors of the Post-Widder and the Gamma operators in Lp(0,∞),1≤p≤∞, with a weight xγ0(1+x)γ∞-γ0 with arbitrary real γ0,γ∞ Characteristics of two types are used - weighted K-functionals of the approximated function itself and the classical fixed-step moduli of smoothness taken on simple modifications of it.