Pointwise approximation of modified conjugate functions by matrix operators of conjugate Fourier series of 2 π / r $2\pi /r$ -periodic functions

Abstract

We extend the results of Xh. Z. Krasniqi (Acta Comment. Univ. Tartu Math. 17:89–101, 2013) and the authors (Acta Comment. Univ. Tartu Math. 13:11–24, 2009; Proc. Est. Acad. Sci. 67:50–60, 2018) to the case when considered function is -periodic and the measure of approximation depends on r-differences of the entries of the considered matrices.