The Rational Function Analogue of a Question of Schur and Exceptionality of Permutation Representations
By Robert M. Guralnick, Peter Müller, Jan Saxl
Available for 61 USD
Investigates the analogous question for rational functions. This book describes the Galois theoretic translation, based on Chebotarev's density theorem, leads to a certain property of permutation groups, called exceptionality.