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Sliceable groups and towers of fields

  • Sigrid Böge EMAIL logo , Moshe Jarden und Alexander Lubotzky
Veröffentlicht/Copyright: 9. April 2016

Abstract

Let l be a prime number, K a finite extension of ℚl, and D a finite-dimensional central division algebra over K. We prove that the profinite group G=D×/K× is finitely sliceable, i.e. G has finitely many closed subgroups H1,...,Hn of infinite index such that G=i=1nHiG. Here, HiG={hghHi,gG}. On the other hand, we prove for l ≠ 2 that no open subgroup of GL2(ℤl) is finitely sliceable and we give an arithmetic interpretation to this result, based on the possibility of realizing GL2(ℤl) as a Galois group over ℚ. Nevertheless, we prove that G = GL2(ℤl) has an infinite slicing, that is G=i=1HiG, where each Hi is a closed subgroup of G of infinite index and HiHj has infinite index in both Hi and Hj if ij.

Funding source: Minerva Foundation

Award Identifier / Grant number: Minkowski Center for Geometry at Tel Aviv University

Funding statement: The second author has been supported by the Minkowski Center for Geometry at Tel Aviv University, established by the Minerva Foundation, and by an ISF grant. The third author acknowledges “Dr. Max Rössler, the Walter Haefner Foundation”, the ETH Foundation, and the ETH Institute for Theoretical Studies for support and hospitality. In addition, the author acknowledges support by ISF and NSF.

We would like to thank Wulf-Dieter Geyer, Michael Larsen, Andrei Rapinchuk, Aharon Razon, and David Zywina for helpful communications and advice.

References

1 E. Artin, Algebraic Numbers and Algebraic Functions, Gordon and Breach, New York, 1967. Suche in Google Scholar

2 A. Borel, Linear Algebraic Groups, 2nd ed., Grad. Texts in Math. 126, Springer, New York, 1991. 10.1007/978-1-4612-0941-6Suche in Google Scholar

3 N. Bourbaki, Lie Groups and Lie Algebras, Chapter 1–3, Springer, Berlin, 1989. 10.1515/9780691223803-002Suche in Google Scholar

4 N. Bourbaki, Algebra II, Chapters 4–7, Springer, Berlin, 1990. Suche in Google Scholar

5 J. W. S. Cassels and A. Fröhlich, Algebraic Number Theory, Academic Press, London, 1967. Suche in Google Scholar

6 J. D. Dixon, M. P. F. du Sautoy, A. Mann and D. Segal, Analytic Pro-p Groups, 2nd ed., Cambridge Stud. Adv. Math. 61, Cambridge University Press, Cambridge, 1999. 10.1017/CBO9780511470882Suche in Google Scholar

7 B. Farb and R. K. Dennis, Noncommutative Algebra, Grad. Texts in Math. 144, Springer, New York, 1993. 10.1007/978-1-4612-0889-1Suche in Google Scholar

8 M. D. Fried and M. Jarden, Field Arithmetic, 3rd ed., Ergeb. Math. Grenzgeb. (3) 11, Springer, Heidelberg, 2008. Suche in Google Scholar

9 G. J. Janusz, Algebraic Number Fields, Academic Press, New York, 1973. Suche in Google Scholar

10 W. Jehne, Kronecker classes of algebraic number fields, J. Number Theory 9 (1977), 279–320. 10.1016/0022-314X(77)90066-XSuche in Google Scholar

11 W. M. Kantor, A. Lubotzky and A. Shalev, Invariable generation of infinite groups, J. Algebra 421 (2015), 296–310. 10.1016/j.jalgebra.2014.08.030Suche in Google Scholar

12 H. Koch, Galoissche Theorie der p-Erweiterungen, Math. Monogr. 10, VEB Deutscher Verlag der Wissenschaften, Berlin, 1970. 10.1007/978-3-642-92997-7Suche in Google Scholar

13 S. Lang, Algebraic Number Theory, Addison-Wesley, Reading, 1970. Suche in Google Scholar

14 S. Lang, Elliptic Functions, Addison-Wesley, Reading, 1973. Suche in Google Scholar

15 S. Lang, Algebra, 3rd ed., Addison-Wesley, Reading, 1993. Suche in Google Scholar

16 M. Larsen and R. Ramakrishna, The inverse Galois problem for p-adic Lie algebras, work in progress. Suche in Google Scholar

17 L. Ribes and P. Zalesskii, Profinite Groups, Ergeb. Math. Grenzgeb. (3) 40, Springer, Berlin, 2000. 10.1007/978-3-662-04097-3Suche in Google Scholar

18 J.-P. Serre, Propriétés galoisiennes des points d'ordere fini des courbes elliptiques, Invent. Math. 15 (1972), 259–331. 10.1007/BF01405086Suche in Google Scholar

19 J.-P. Serre, Lie Algebras and Lie Groups, Lectures Notes in Math. 1500, Springer, Berlin, 1992. 10.1007/978-3-540-70634-2Suche in Google Scholar

Received: 2015-6-27
Published Online: 2016-4-9
Published in Print: 2016-5-1

© 2016 by De Gruyter

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