Combinatorial cycles of a polynomial map over a commutative field
A map g from a field K into itself is said to have a cycle of length n if there exist n distinct elements \(x_ 1,...,x_ n\) of K such that \(g(x_ i)=x_{i+1}\) for \(1\leq i\leq n-1\) and \(g(x_ n)=x_ 1\). Let K be algebraically closed and let \(f\in K[x]\) with deg(f)\(\geq 2\). Let t be a prime number different from the characteristic of K and different from the multiplicative orders of the roots of unity u of the form \(u=f'(c)\) with \(f(c)=c\). Then it is shown that the map from K into itself induced by f has a cycle of length t. For finite fields K the action of the Frobenius automorphism on the cycles of polynomial maps is also studied.
scientific article; zbMATH DE number 3959581