About the (Hahn) classical character of 2-orthogonal solutions of two families of differential equations of third order

Abstract

Considering a differential operator of third order that does not increase the degree of polynomials, we analyse some properties of elements of the dual space of 2-orthogonal polynomial eigenfunctions. In two classes of such generic operator, we prove that a 2-orthogonal polynomial solution fulfils Hahn's property.

arXiv admin note: text overlap with arXiv:1609.04540