“…Other classical applications of the solutions of these problems to analytic number theory include Hilbert-type inequalities [8,16,24,29,35], Erdös-Turán discrepancy inequalities [8,21,35], optimal approximations of periodic functions by trigonometric polynomials [2,8,9,35] and Tauberian theorems [16]. The extremal problem in higher dimensions, with applications, is considered in [1,17].…”