The unit group of an integral group ring

It is well know that the unit group U of the integral group ring ZG of a final group G is presented. in recent years substential progress has been made on en expliciet description of finitely many generattors of a subgroup of finily index in U. Also free subgroups of 2 have been described and some non communative structure theories have been obtained. The main gaels of this project are to investigate the following aspects of the algebra structure of U: (1) structure theries, that is, determine when all free subgroups of index in U belong to a particular class of groups, (2) explicit descriptions of free products in U and this also inlinear groups and motivation groups, (3) expicit desription of finitely many generators for subgroup of finil index in the group of an order of a division my, (4) also deal with groups G, (5) investigate the structure of U in relationship with the isomorphism problem