PageHeader : Funkcialaj Ekvacioj, 21 (1978) 1-9 Title : On Differential Equations for Orthogonal Polynomials AuthorInfo : By AuthorInfo : Wolfgang HAHN AuthorInfo : (Technische Universitat Graz, Austria) section : 1. section : 2. section : 2. section : 3. section : 4. section : $u_{a}$ , $u_{a}+\frac{1}{\kappa}v_{a}$ , $f(u_{a}+\frac{1}{\kappa}v_{a})$ which is of type (8). Thus we are justified to exclude the possibility (7). section : 5. section : 6, section : 7. section : Literature