A note on semi-classical orthogonal polynomials (Q1914909)

The author studies the characterization of semi-classical monic orthogonal polynomial sequences (MOPS). Orthogonality is defined with respect to a linear functional on the linear space of polynomials with real coefficients and the main results are twofold: (1) full characterization of classical MOPS (correction on \textit{F. Marcellán, A. Branquinho} and \textit{J. Petronilho} [Acta Appl. Math. 34, No. 3, 283-303 (1994; Zbl 0793.33009)]), (2) proof that the characterization property, in the form given in the previous item, can not be exteded to semi-classical MOPS. A nicely written note.