ON THE INDEX OF THE GROUP OF UNITS OF THE INTEGRAL GROUP RING OF FINITE ABELIAN GROUPS
Let G be an abelian group of order n and let denote the unit group of the group ring of G over the integers. In this paper, we show how to compute quickly a bound on the index of in the unit group of the product G of certain cyclotomic rings, whose structure is very well known, in which is naturally embedded.
abelian number fields, integral representations.