The upper central series of the unit group of an integral group ring. (English) Zbl 1078.16029

Li, Yuanlin; Parmenter, M. M.

Commun. Algebra 33, No. 5, 1409-1415 (2005).

Let \(Z_n(U)\) denote the \(n\)-th term of the upper central series of the unit group \(U=U(\mathbb{Z} G)\) of the integral group ring \(\mathbb{Z} G\) and \(\widetilde Z=\bigcup^\infty_{i=1}Z_n(U)\). The authors show that if the set of the torsion elements of \(G\) forms a subgroup \(T\) and \(\widetilde Z\not\subset C_U(T)\), then \(T\) is either an Abelian 2-group or a \(Q\)-group [for the definition of \(Q\)-group see S. R. Arora and I. B. S. Passi, Commun. Algebra 21, No. 10, 3673-3683 (1993; Zbl 0788.16024)]. Moreover, if \(T\) is a subgroup of \(G\) and \(\widetilde Z\subseteq N_U(G)\), then \(\widetilde Z\subseteq G\cdot C_U(T)\). Recall that if \(G\) is an FC-group, then the property \(\widetilde Z\subseteq N_U(G)\) holds [see the authors, Commun. Algebra 31, No. 7, 3207-3217 (2003; Zbl 1034.16037)].

Reviewer: S. V. Mihovski (Plovdiv)

MSC:

16U60	Units, groups of units (associative rings and algebras)
20C07	Group rings of infinite groups and their modules (group-theoretic aspects)
16S34	Group rings
20F14	Derived series, central series, and generalizations for groups
20E07	Subgroup theorems; subgroup growth

Keywords:

Bass cyclic units; \(Q\)-groups; unipotent units; upper central series; integral group rings; torsion subgroups

Citations:

Zbl 0788.16024; Zbl 1034.16037

References:

[1]	Arora S. R., Comm. Algebra 21 pp 3673– (1993) · Zbl 0788.16024
[2]	Arora S. R., Comm. Algebra 21 pp 25– (1993) · Zbl 0784.16020
[3]	Jespers E., J. Algebra 247 pp 24– (2002) · Zbl 1063.16036
[4]	Li Y., Canadian Journal of Mathematics 50 pp 401– (1998) · Zbl 0912.16013
[5]	Li Y., Bull. Austral. Math. Soc. 67 pp 171– (2003) · Zbl 1026.16019
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[7]	Li Y., Comm. Algebra 31 pp 3207– (2003) · Zbl 1034.16037
[8]	Sehgal S. K., Units in Integral Group Rings (1993) · Zbl 0803.16022