On some inequalities established when presenting the Schwartz-Poincare - Steklov method and also encountered in solving many minimal problems

Abstract

In various mathematical studies related to the question of the existence of a minimum, it is often useful, as we will try to show below, the application of that basic relationship in the theory of trigonometric series, which was named by Prof. V. A. Steklov as a closed equation and generalized by him for many other systems of orthogonal functions found in analysis and mathematical physics.