%0 Journal Article %T Hypercentral unit groups and the hyperbolicity of a modular group algebra %A E. Iwaki %A S. O. Juriaans %J Mathematics %D 2006 %I arXiv %X We classify groups G such that the unit group U(ZG) is hypercentral. In the second part we classify groups G whose modular group algebra has hyperbolic unit group V(KG). %U http://arxiv.org/abs/math/0610803v1