Torsion-free crystallographic groups with indecomposable holonomy group. II
Torsion-free crystallographic groups with indecomposable holonomy group. II
Let K be a principal ideal domain, G a finite group, and M a KG-module which is a free K-module of finite rank on which G acts faithfully. A generalized crystallographic group is a non-split extension ℭ of M by G such that conjugation in ℭ induces the G-module structure …