Strengthening of Kolmogorov Type Inequalities for Derivatives and Differences

详细

We propose a new method for constructing extremal operators in the problem for obtaining the best approximation of the differentiation operator by bounded operators. Using the new form of extremal operators and their deviations, we strengthen the Kolmogorov inequality by expanding the right-hand side with respect to differences of a function and its higher order derivative with preservation of sharpness.