BEST QUADRATURE FORMULAS FOR CLASSES OF DIFFERENTIABLE FUNCTIONS AND PIECEWISE-POLYNOMIAL APPROXIMATION
N P Korneĭčuk, N E Lušpaĭ · Mathematics of the USSR-Izvestiya · 1969
In this article we obtain characteristic properties of piecewise-polynomial functions (spline functions) that have least deviation from zero in the metric of C. This has allowed us to obtain quadrature formulas with least estimate of the remainder on a number of classes of differentiable functions.