Published online by Cambridge University Press: 20 November 2018
Pólya (3) has shown that if bnis a sequence of algebraic integers and is a rational function, then so is . This result was generalized by Uchiyama (5) who showed that one may replace the assumption that the bn are algebraic integers by the assumption that the bn lie in a finitely generated submodule of the complex numbers, and by the author (1) who showed that if p is a non-zero polynomial with complex coefficients and if bn is a sequence of algebraic integers such that is a rational function, then so is . Our aim in this note is to give a common generalization of all of these theorems.