Una nota sui gruppi policiclici che ammettono un automorfismo con numero di Reidemeister finito.

Let G be a group and f an automorphism of G. Two elements x,y in G are called f-conjugate if there exists g in G such that x=g^-1*y*g^f. It is easily verified that the f-conjugation is an equivalence relation ; the number R(f) of f-classes of G is called the Reidemeister number of the automorphism f. In this paper we prove that if a polycyclc group G admits an automorphism of order n such that R(f) is finite, then G contains a subgroup of finite index with derived length at most 2^(n-1).