Abstract:
It is proved that for q-convex polynomial approximations, where q⩾4 , inequalities of Jackson type are not valid even with a constant depending on the approximated function.
Citation:
A. V. Bondarenko, A. V. Primak, “Negative Results in Form-Preserving Approximation of Higher Order”, Mat. Zametki, 76:6 (2004), 812–823; Math. Notes, 76:6 (2004), 758–769