Properties of Cesàro means for generalized orthosimilar nonnegative expansion systems (Q1405912)

Classical results [\textit{G. Alexits}, Convergence problems of orthogonal series (Inostr. Literatura, Moscow) (1963; Zbl 0114.27104) and (Pergamon Press, New York, etc.) (1961; Zbl 0098.27403); \textit{S. Kachmazh} and \textit{G. Shteingaus}, Theory of orthogonal series (GIFML, Moscow) (1958)] are extended to the generalized orthosimilar nonnegative systems [\textit{T. P. Lukashenko}, Vestn. Mosk. Univ., Ser. I 1998, 6-10 (1998; Zbl 1029.42024)]. Some results on summability of orthogonal series by the Cesàro means methods are presented.