Izv. Akad. Nauk SSSR Ser. Mat., 1968 Volume 32, Issue 4,Pages 756–771(Mi im2489)
Linear summability methods for expansions of functions in the classes $L^p_\mu$$(1\leqslant p\leqslant\infty)$ in orthonormal systems of polynomial type
Abstract:
In this article, sufficient conditions are derived under which, for all $x\in E\subset[a,b]$ (or uniformly on some set $E_1\subset[a,b]$), the following relation holds:
$$
\lim_{n\to\infty}U_n(f,x,\Lambda)=f(x),
$$
where the $U_n(f,x,\Lambda)$ are linear means of expansions of functions in the classes $L^p_\mu$$(1\leqslant p\leqslant\infty)$ in orthonormal systems of polynomial type.