Hostname: page-component-586b7cd67f-vdxz6 Total loading time: 0 Render date: 2024-11-24T10:49:10.811Z Has data issue: false hasContentIssue false

The Residual Finiteness of Polygonal Products—Two Counterexamples

Published online by Cambridge University Press:  20 November 2018

R. B. J. T. Allenby*
Affiliation:
School of Mathematics, University of Leeds Leeds, LS2 9JT England
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

We show that, even under very favourable hypotheses, a polygonal product of finitely generated torsion free nilpotent groups amalgamating infinite cyclic subgroups is, in general, not residually finite, thus answering negatively a question of C. Y. Tang. A second example shows similar kinds of limitations apply even when the factors of the product are free abelian groups.

Type
Research Article
Copyright
Copyright © Canadian Mathematical Society 1994

References

1. Allenby, R. B. J. T., The potency of cyclically pinched one-relator groups, Arch. Math. 36(1981), 204210.Google Scholar
2. Allenby, R. B. J. T. and Tang, C. Y., On the residual finiteness of certain polygonal products, Canad. Math. Bull. 32(1989), 1117.Google Scholar
3. Brunner, A. M., Frame, A. L., Lee, Y. W. and Wielenberg, N. J., Classifying the torsion-free subgroups of the Picard group, Trans. Amer. Math. Soc. 282(1984), 205235.Google Scholar
4. Higman, G., A finitely generated infinite simple group, J. London Math. Soc. 26(1951), 6164.Google Scholar
5. Karrass, A., Pietrowski, A. and Solitar, D., The subgroups of a polygonal product of groups, unpublished manuscript.Google Scholar
6. Kim, Goansu, On polygonal products of finitely generated abelian groups, Bull. Austral. Math. Soc. 45 (1992), 453462.Google Scholar
7. Kim, G. and Tang, C. Y., On the residual finiteness of polygonal products of nilpotent groups, Canad. Math. Bull. 35(1992), 390399.Google Scholar
8. Pride, Stephen J., Groups with presentations in which each defining relator involves exactly two generators, J. London Math. Soc. (2) 36(1987), 245256.Google Scholar