A new proof of an identity of Jetter and Stöckler for multivariate Bernstein polynomials (Q2494704)

In a recent paper [Aided Geom. Des. 20, No. 8--9, 563--577 (2003; Zbl 1069.41501)], \textit{K. Jetter} and \textit{J. Stöckler} have shown a pointwise orthogonality relation of multivariate Bernstein polynomials, useful for the representation of the dual basis of those polynomials. In the present paper a simpler proof of that identity is given, by using the generating function of Bernstein polynomials on the simplex. By the same method some similar identities are obtained for other univariate differential operators and generating functions.