2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/68445Sufficient conditions are developed for a class of generalized Polya urn schemes ensuring exchangeability. The extended class includes the Blackwell-MacQueen Polya urn and the urn schemes for the two-parameter Poisson-Dirichlet process and finite dimensional Dirichlet priors among others.Probabilitytext