Congruence subgroups in group rings^*

^*Research supported in part by F.W.O. Belgium and CNPq Brasil. 1991 Mathematics Subject Classification. 16U60, 16S34, 20C05

Abstract

For a large class of groups G a precise congruence subgroup of the group generated by the bicyclic units of the integral group ring ZG is determined. As an application an upper bound is calculated for the index in the unit group of ZG for the group generated by the Bass cyclic units and the bicyclic units.

1991Mathematics subject classification:

• 16U60
• 16S34
• 20C05

^*Research supported in part by F.W.O. Belgium and CNPq Brasil. 1991 Mathematics Subject Classification. 16U60, 16S34, 20C05

^*Research supported in part by F.W.O. Belgium and CNPq Brasil. 1991 Mathematics Subject Classification. 16U60, 16S34, 20C05

Notes

^*Research supported in part by F.W.O. Belgium and CNPq Brasil. 1991 Mathematics Subject Classification. 16U60, 16S34, 20C05