Pointwise convergence of Fourier-Jacobi series

Abstract

The purpose of this paper is to study the pointwise and almost everywhere convergence of the Cesaro means (C,δ) of Fourier-Jacobi expansions, the main term of the Lebesgue constant of the (C,δ) means for −1 α+1/2 and equiconvergence theorems for −1<δ≤α+1/2 are proved. The analogues of the Lebesgue, Salem and Young theorems of the Cesaro means at the critical index δ=α+1/2 are established.