Construction of bases for the group of cyclotomic units

Abstract

Subject of investigation is the construction of a basis Bn for the group of cyclotomic units of the nth cyclotomic field. These bases have the property that Bd⊆Bn for d ∣ n. For this purpose the notion of weak σ-bases of a module with an involution operating on it is introduced. The weak σ-basis of a special module then leads via explicit given isomorphisms to the desired bases for the group of cyclotomic units.