Some properties of nilpotent groups

• Published in: Algebra and Discrete Mathematics
• Date: 2009
• Main Authors: Gaglione, A.M., Lipschutz, S., Spellman, D.
• Format: Article
• Language: English
• Published: Інститут прикладної математики і механіки НАН України 2009
• Online Access: https://nasplib.isofts.kiev.ua/handle/123456789/154599
• Journal Title: Digital Library of Periodicals of National Academy of Sciences of Ukraine
• Cite this: Some properties of nilpotent groups / A.M. Gaglione, S. Lipschutz, D. Spellman // Algebra and Discrete Mathematics. — 2009. — Vol. 8, № 4. — С. 66–77. — Бібліогр.: 8 назв. — англ.

Property S, a finiteness property which can hold in infinite groups, was introduced by Stallings and others and shown to hold in free groups. In [2] it was shown to hold in nilpotent groups as a consequence of a technical result of Mal'cev. In that paper this technical result was dubbed property R. Hence, more generally, any property R group satisfies property S. In [7] it was shown that property R implies the following (labeled there weak property R) for a group G: If G₀ is any subgroup in G and G₀* is any homomorphic image of G₀, then the set of torsion elements in G₀* forms a locally finite subgroup. It was left as an open question in [7] whether weak property R is equivalent to property R. In this paper we give an explicit counterexample thereby proving that weak property R is strictly weaker than property R.