On a problem concerning permutation polynomials
Gerhard Turnwald · Transactions of the American Mathematical Society · 1987
Let $S(f)$ denote the set of integral ideals $I$ such that $f$ is a permutation polynomial modulo $I$, where $f$ is a polynomial over the ring of integers of an algebraic number field. We obtain a classification for the sets $S$ which may be written in the form $S(f)$.