Multiplier Theorem for Fourier Series in continuous-discrete Sobolev orthogonal polynomials

Abstract

In the paper we study the multipliers of Fourier series in polynomials orthogonal in continuous-discrete Sobolev's spaces. Multiplier Theorem for Fourier-Sobolev series is obtained. This result is based on the representation of the Fej\'er kernel, on the construction of the "humpbacked majorant" and weighted estimates of maximal functions.