SEMINARIO DE FISICA TEORICA I Y II Titulo: Heisenberg algebra, Umbral Calculus and Orthogonal Polynomials Conferenciante: Prof. P. Winternitz (Centre de recherches mathematiques, Univ. Montreal) Dia y hora: 27, 14:15 (Aula 8B) Resumen: Umbral calculus can be viewed as an abstract theory of the Heisenberg commutation relation [P,M]=1. In ordinary quantum mechanics P is the derivative and M the coordinate operator. Here we shall realize P as a second order differential operator and M as a first order integral one. We show that this makes it possible to solve large classes of differential and integro-differential equations and to introduce new classes of orthogonal polynomials, related to Laguerre polynomials. Applications of the polynomials in optics will be discussed. The results were obtained in collaboration with G.Dattoli and D.Levi.