Abstract

We continue the investigation initiated by Mastroianni and Szabados on question whether Jackson's order of approximation can be attained by Lagrange interpolation for a wide class of functions. Improving a recent result of Mastroianni and Szabados, we show that for a subclass of C1 functions the local order of approximation given by Lagrange interpolation can be much better (of at least O(1n)) than Jackson's order.