Table look-up method for the evaluation of functions (Q1592406)

In this ``Letter to the editor'' the authors remind the reader of the old method of equidistant tabulation of functions as a means of approximation. They give and prove an error estimate (of first order in the step-length) for functions Lipschitz-continuous on a compact interval of the real line and for such functions which are, in addition, monotone. The reviewer now asks why the authors have not added a few more lines to provide also the well-known error estimate (of second order in the mesh-width) for linear interpolation of functions whose first derivative is Lipschitz-continuous.