A Voronovskaja type formula for Soardi's operators (Q2131876)

\textit{P. M. Soardi} in [Probability measures on groups. X. Proceedings of the tenth Oberwolfach conference, held November 4-10, 1990 in Oberwolfach, Germany. New York, NY: Plenum Publishing Corporation. 387--393 (1991; Zbl 0821.60013)] introduced a sequence of positive linear operators associating to each function \(f\in[0,1]\) a polynomial function which is closely related to the Bernstein polynomials on \([-1, +1]\). This paper is devoted to certain properties of Soardi's operators. Here authors derive Voronovskaja-type results for such operators and estimate moments and establish rate of convergence.