Constructing free subgroups of integral group ring units

Marciniak, Zbigniew; Sehgal, Sudarshan

doi:10.1090/S0002-9939-97-03812-4

Constructing free subgroups of integral group ring units
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by Zbigniew S. Marciniak and Sudarshan K. Sehgal PDF

Proc. Amer. Math. Soc. 125 (1997), 1005-1009 Request permission

Abstract:

Let $G$ be an arbitrary group. It is proved that if $\mathbb {Z}G$ contains a bicyclic unit $u\ne 1$, then $\langle u,u^*\rangle$ is a nonabelian free subgroup of invertible elements.

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