G. We show that if U contains G
as a subgroup of finite index, then U = G. This result can be used
to give an alternative proof of a recent result of Marciniak and
Sehgal on units in the integral group ring of a crystallographic group.
Daniel R. Farkas and Peter A. Linnell
Let G be an arbitrary group and let U be a subgroup of the
normalized units in
G. We show that if U contains G
as a subgroup of finite index, then U = G. This result can be used
to give an alternative proof of a recent result of Marciniak and
Sehgal on units in the integral group ring of a crystallographic group.