Orthogonal and Pseudo-Orthogonal Multidimensional Appell Polynomials.
More than one hundred years, Appell introduced a polynomials class characterized by the exponentials form of its generatrice function. This class is well known on R and the aim of the paper is to offer a multidimensional analysis in two directions: we indicate a classical characterization of the Appell on Rd via their generatrice function and we investigate their orthogonality.