Über maximale arithmetisch definierte Gruppen.
In [3], the authors initiated a technique of using affine representations to study the groups of units of integral group rings of crystallographic groups. In this paper, we use this approach for some special classes of crystallographic groups. For a first class of groups we obtain a normal complement for the group inside the group of normalized units. For a second class of groups we show that the Zassenhaus conjectures ZC1 and ZC3 are valid. This generalizes the results known for the infinite dihedral...
We describe subgroups of GL2A which are normalized by elementary matrices for rings A satisfying the first stable range condition, Banach algebras A, von Neumann regular rings A, and other rings A.