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On the generic type of the free group

Published online by Cambridge University Press:  12 March 2014

Rizos Sklinos*
Affiliation:
School of Mathematics, University of Leeds, Leeds, LS2 9JT, UK, E-mail: rsklinos@maths.leeds.ac.uk

Abstract

We answer a question raised in [9], that is whether the infinite weight of the generic type of the free group is witnessed in Fω. We also prove that the set of primitive elements in finite rank free groups is not uniformly definable. As a corollary, we observe that the generic type over the empty set is not isolated. Finally, we show that uncountable free groups are not ℵ1-homogeneous.

Type
Research Article
Copyright
Copyright © Association for Symbolic Logic 2011

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References

REFERENCES

[1]Lyndon, R. C. and Schupp, P. E., Combinatorial group theory, Springer-Verlag, 1977.Google Scholar
[2]Marker, D., Model theory: An introduction, Springer, 2002.Google Scholar
[3]Martino, A. and Ventura, E., Examples of retracts in free groups that are not the fixed subgroup of any automorphism, Journal of Algebra, vol. 87 (2003), pp. 735747.CrossRefGoogle Scholar
[4]Nielsen, J., Die Isomorphismen der allgemeinen unendlichen Gruppe mit zwei Erzeugenden, Mathematische Annalen, vol. 78 (1918), pp. 385397.CrossRefGoogle Scholar
[5]Nies, A., Aspects of free groups, Journal of Algebra, vol. 263 (2003), pp. 119125.CrossRefGoogle Scholar
[6]Perin, C., Plongements élémentaires dans un groupe hyperbolique sans torsion, Ph.D. thesis, Caen, 10 2008.Google Scholar
[7]Pillay, A., Geometric stability theory, Oxford University Press, 1996.CrossRefGoogle Scholar
[8]Pillay, A., Forking in the free group, Journal of the Institute of Mathematics of Jussieu, vol. 7 (2008), pp. 375389.CrossRefGoogle Scholar
[9]Pillay, A., On genericity and weight in the free group, Proceedings of the American Mathematical Society, vol. 137 (2009), pp. 39113917.CrossRefGoogle Scholar
[10]Poizat, B., Groupes stables avec types generiques reguliers, this Journal, vol. 48 (1983), pp. 641658.Google Scholar
[11]Pillay, A., Stable groups, Mathematical Surveys and Monographs, vol. 87, American Mathematical Society, 2001.Google Scholar
[12]Sela, Z., Diophantine geometry over groups VIII: Stability, (arXiv:math/0609096vl).Google Scholar
[13]Sela, Z., Diophantine geometry over groups VI: The elementary theory of free groups, Geometric and Functional Analysis, vol. 16 (2006), pp. 707730.Google Scholar
[14]Stallings, J. R., Whitehead graphs on handlebodies, Geometric group theory down under (Canberra 1996), de Gruyter, Berlin, 1999, pp. 317330.Google Scholar