Raising and lowering operators, factorization and differential/difference operators of hypergeometric type

Starting from the Rodrigues formula we present a general construction of ra ising and lowering operators for orthogonal polynomials of continuous and d iscrete variables on a uniform lattice. In order to have these operators mu tually adjoint we introduce orthonormal functions with respect to the scala r product of unit weight. Using the Infeld-Hull factorization method, we ge nerate from the raising and lowering operators the second-order self-adjoin t differential/difference operator of hypergeometric type.