“…Questions that arise in economics, physics, biology, etc., lead to mathematical models, which are often formulated in the form of functional equations of various types, in particular, differential, integro-differential and difference equations (see, for example, [1][2][3][4][5][6][7]). One of the fundamental problems in approaches to finding solutions of such equations is the reconstruction of functions of one or several variables, as well as problems that arise in the development and implementation of effective methods and algorithms for representing and approximating the functions of one or several variables.…”