Third degree classical forms
The author investigates the problem of the characterization and of the determination of semi-classical forms which are third degree regular forms (TDRF). At first some necessary conditions are given to impound that a semi-classical form is (TDRF) but not of second degree. So one can determine all classical forms which are (TDRF). It is shown that Hermite, Laguerre and Bessel forms are not (TDRF), but Jacobi forms are (TDRF) under additional conditions on the parameters.
scientific article; zbMATH DE number 1879005