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Instability of nondiscrete free subgroups in lie groups

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Abstract

We study finitely-generated nondiscrete free subgroups in Lie groups. We address the following question first raised by Étienne Ghys: is it always possible to make arbitrarily small perturbations of the generators of the free subgroup in such a way that the new group formed by the perturbed generators be not free? In other words, is it possible to approximate generators of a free subgroup by elements satisfying a nontrivial relation? We prove that the answer to Ghys’ question is positive and generalize this result to certain nonfree subgroups. We also consider the question on the best approximation rate in terms of the minimal length of relation in the approximating group. We give an upper bound on the optimal approximation rate as \( {e^{ - c{l^\kappa }}} \), where c > 0 is a constant, l the minimal length of relation and 0.19 < κ < 0.2.

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References

  1. H. Abels, G. A. Margulis, G. A. Soifer, Semigroups containing proximal linear maps, Israel J. Math. 91 (1995), 1–30.

    Article  MathSciNet  MATH  Google Scholar 

  2. В. И. Арнолъд, Дополнительные главы теории обыкновенных дифференциальных уравнений, Наука, М., 1978. French transl.: V. Arnol’d, Chapitres Supplémentaires de la Théorie des Équations Différentielles Ordinaires, Mir, Moscow, 1980.

  3. E. Breuillard, Propriétés Qualitatives des Groupes Discrets, Notes du cours Peccot au Collège de France, 2006, http://www.math.u-psud.fr/~breuilla/Peccot4.pdf.

  4. E. Breuillard, T. Gelander, On dense free subgroups of Lie groups, J. Algebra 261 (2003), no. 2, 448–467.

    Article  MathSciNet  MATH  Google Scholar 

  5. G. Brown, G. On commutators in a simple Lie algebra, Proc. Amer. Math. Soc. 14 (1963), 763–767.

    Article  MathSciNet  MATH  Google Scholar 

  6. C. M. Dawson, M. A. Nielsen, The Solovay–Kitaev algorithm, Quantum Inf. Comput. 6 (2006), no. 1, 81–95.

    MathSciNet  MATH  Google Scholar 

  7. A. Gamburd, D. Jakobson, P. Sarnak, Spectra of elements in the group ring of SU(2), J. Eur. Math. Soc. 1 (1999), no. 1, 51–85.

    Article  MathSciNet  MATH  Google Scholar 

  8. H. Garland, M. S. Raghunathan, Fundamental domains for lattices in (-)rank 1 semisimple Lie groups, Ann. of Math. 92 (1970), no. 2, 279–326.

    Article  MathSciNet  Google Scholar 

  9. T. Gelander, On deformations of F n in compact Lie groups, Israel J. Math. 167 (2008), 15–26.

    Article  MathSciNet  MATH  Google Scholar 

  10. É. Ghys, Y. Carrière, Relations d’équivalence moyennables sur les groupes de Lie, C. R. Acad. Sci. Paris Sér. I Math. 300 (1985), no. 19, 677–680.

    MATH  Google Scholar 

  11. И. А. Горбовицкцкис, Нормальные формы семейств отображений в области Пуанкаре, Тр. Мат. инст. им. В. А. Стеклова 254 (2006), 101–110. Engl. transl.: I. A. Gorbovitskis, Normal forms of families of mappings in the Poincaré domain, Proc. Steklov Inst. Math. 254 (2006), no. 1, 94–102.

  12. M. Goto, A theorem on compact semi-simple groups, J. Math. Soc. Japan 1 (1949), 270–272.

    Article  MathSciNet  MATH  Google Scholar 

  13. A. Guichardet, Cohomologie des Groupes Topologiques et des Algèbres de Lie, Textes Mathématiques, Vol. 2, CEDIC, Paris, 1980. Russian transl.: А. Гишарде, Когомологии топологических групп и алгебр Ли, Мир, М., 1984.

  14. D. B. A. Epstein, Almost all subgroups of a Lie group are free, J. Algebra 19 (1971), 261–262.

    Article  MathSciNet  MATH  Google Scholar 

  15. N. Hitchin, Lie groups and Teichmüller space, Topology 31 (1992), no 3, 449–473.

    Article  MathSciNet  MATH  Google Scholar 

  16. Yu. S. Ilyashenko, A. S. Pyartli, The monodromy group at infinity of a generic polynomial vector field on the complex projective plane, Russian J. Math. Phys. 2 (1994), no. 3, 275–315.

    MathSciNet  MATH  Google Scholar 

  17. Yu. S. Ilyashenko, S. Yu. Yakovenko, Lectures on Analytic Differential Equations, Graduate Studies in Mathematics, Vol. 86, American Mathematical Society, Providence, RI, 2008.

    MATH  Google Scholar 

  18. D. Johnson, J. J. Millson, Deformation spaces associated to compact hyperbolic manifolds, in: Discrete Groups in Geometry and Analysis, papers in honor of G. D. Mostow on his 60th birthday, R. Howe, ed., Progress in Mathematics, Vol. 67, Birkhäuser, 1987, pp. 48–106.

  19. V. Kaloshin, I. Rodnianski, Diophantine properties of elements of SO(3), Geom. Funct. Anal. 11 (2001), no. 5, 953–970.

    Article  MathSciNet  MATH  Google Scholar 

  20. А. Ю. Китаев, Квантовые вычисления: алгоритмы и исправление ошибок, УМН 52 (1997), no. 6 (318), 53–112. English transl.: A. Yu. Kitaev, Quantum computations: algorithms and error correction, Russian Math. Surveys 52 (1997), no. 6, 1191–1249.

  21. M. Kuranishi, On everywhere dense embedding of free groups in Lie groups, Nagoya Math. J. 2 (1951), 63–71.

    MathSciNet  MATH  Google Scholar 

  22. F. Labourie, Anosov flows, surface groups and curves in projective space, Invent. Math. 165 (2006), 51–114.

    Article  MathSciNet  MATH  Google Scholar 

  23. A. Lubotzky, Free quotients and the first Betti number of some hyperbolic manifolds, Transform. Groups 1 (1996), nos. 1–2, 71–82.

    Article  MathSciNet  MATH  Google Scholar 

  24. M. A. Nielsen, I. L. Chuang, Quantum Computation and Quantum Information, Cambridge University Press, Cambridge, 2000.

    MATH  Google Scholar 

  25. S. Pasiencier, H.-C. Wang, Commutators in a semisimple Lie group, Proc. Amer. Math. Soc. 13 (1962), no. 6, 907–913.

    Article  MathSciNet  MATH  Google Scholar 

  26. R. Ree, Commutators in semisimple algebraic groups, Proc. Amer. Math. Soc. 15 (1964), no. 3, 457–460.

    Article  MathSciNet  MATH  Google Scholar 

  27. D. Sullivan, Quasiconformal homeomorphisms and dynamics II, Acta Math. 155 (1985), 243–260.

    Article  MathSciNet  MATH  Google Scholar 

  28. J. Tits, Free subgroups in linear groups, J. Algebra 20 (1972), 250–270.

    Article  MathSciNet  MATH  Google Scholar 

  29. З. Б. Винберг, А. Л. Онищик, Семинар по группам Ли и алгебраическим группам, УРСС, М., 1995. [E. B. Vinberg, A. L. Onishchik, Seminar on Lie Groups and Algebraic Groups, 2nd ed., URSS, Moscow, 1995 (Russian)].

  30. A. Weil, Remarks on the cohomology of groups, Annals of Math. 80 (1964), 149–157.

    Article  MathSciNet  Google Scholar 

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Correspondence to Alexey Glutsyuk.

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Supported in part by RFBR grants 02-01-00482, 02-01-22002, 07-01-00017-a and NTsNIL_a (RFBR-CNRS) 05-01-02801, NTsNIL_a (RFBR-CNRS) 10-01-93115.

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Glutsyuk, A. Instability of nondiscrete free subgroups in lie groups. Transformation Groups 16, 413–479 (2011). https://doi.org/10.1007/s00031-011-9134-9

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