Abstract
In this article the study of the Prime Graph Question for the integral group ring of almost simple groups which have an order divisible by exactly 4 different primes is continued. We provide more details on the recently developed “lattice method” which involves the calculation of Littlewood-Richardson coefficients. We apply the method obtaining results complementary to those previously obtained using the HeLP-method. In particular the “lattice method” is applied to infinite series of groups for the first time. We also prove the Zassenhaus Conjecture for four more simple groups. Furthermore we show that the Prime Graph Question has a positive answer around the vertex 3 provided the Sylow 3-subgroup is of order 3.
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Allen, P.J., Hobby, C.: A characterization of units in Z[A 4]. J. Algebra 66(2), 534–543 (1980)
Bächle, A., Margolis, L.: HeLP – A GAP-package for torsion units in integral group rings. preprint, arXiv:1507.08174 [math.RT] p. 6 (2015)
Bächle, A., Margolis, L.: HeLP – Hertweck-Luthar-Passi method, GAP package, Version 3.0 http://homepages.vub.ac.be/abachle/help/ (2016)
Bächle, A., Margolis, L.: On the prime graph question for integral group rings of 4-primary groups I. Internat. J. Algebra Comput. 27(6), 731–767 (2017)
Bächle, A., Margolis, L.: Rational conjugacy of torsion units in integral group rings of non-solvable groups. Proc. Edinb. Math. Soc. (2) 60(4), 813–830 (2017)
Bovdi, V.A., Konovalov, A.B., Linton, S.: Torsion units in integral group ring of the Mathieu simple group M22. LMS J. Comput. Math. 11, 28–39 (2008)
Breuer, T.: The GAP character table library, version 1.2.1. http://www.math.rwth-aachen.de/~Thomas.Breuer/ctbllib. GAP package (2012)
Caicedo, M., Margolis, L., del Río, Á.: Zassenhaus conjecture for cyclic-by-abelian groups. J. Lond. Math. Soc. (2) 88(1), 65–78 (2013)
Cohn, J. A., Livingstone, D.: On the structure of group algebras. I. Canad. J. Math. 17, 583–593 (1965)
Curtis, C., Reiner, I.: With applications to finite groups and orders, Reprint of the 1981 original, A Wiley-Interscience Publication. Wiley, New York (1990)
Dieterich, E.: Representation types of group rings over complete discrete valuation rings. II. In: Orders and their Applications (Oberwolfach, 1984), Lecture Notes in Math., vol. 1142, pp. 112–125. Springer, Berlin (1985)
The GAP Group: GAP – Groups, Algorithms, and Programming, Version 4.8.3 http://www.gap-system.org (2016)
Geck, M.: Irreducible Brauer characters of the 3-dimensional special unitary groups in nondefining characteristic. Comm. Algebra 18(2), 563–584 (1990)
Gildea, J.: Zassenhaus conjecture for integral group ring of simple linear groups. J. Algebra Appl. 12(6), 1350,016, 10 (2013)
Gudivok, P.: Representations of finite groups over number rings. Izv. Akad. Nauk SSSR, Ser. Mat. 31(4), 799–834 (1967). Russian. (Series also available in English.)
Hertweck, M.: On the torsion units of some integral group rings. Algebra Colloq. 13(2), 329–348 (2006)
Hertweck, M.: Partial augmentations and Brauer character values of torsion units in group rings p. 16. Manuscript, arXiv:math/0612429v2 [math.RA] (2007)
Hertweck, M.: Zassenhaus conjecture for A 6. Proc. Indian Acad. Sci. Math. Sci. 118(2), 189–195 (2008)
Hertweck, M., Höfert, C., Kimmerle, W.: Finite groups of units and their composition factors in the integral group rings of the group P S L(2,q). J. Group Theory 12(6), 873–882 (2009)
Higman, G.: Units in Group Rings. D. phil. thesis, Oxford Univ (1940)
Hughes, I., Pearson, K.R.: The group of units of the integral group ring Z S 3. Canad. Math. Bull. 15, 529–534 (1972)
Huppert, B.: Endliche Gruppen. I Die Grundlehren der Mathematischen Wissenschaften, vol. 134. Springer-Verlag, Berlin-New York (1967)
Huppert, B., Blackburn, N.: Finite groups. II Die Grundlehren der Mathematischen Wissenschaften, vol. 242. Springer-Verlag, Berlin-New York (1982)
Huppert, B., Blackburn, N.: Finite groups. III Die Grundlehren der Mathematischen Wissenschaften, vol. 243. Springer-Verlag, Berlin-New York (1982)
Isaacs, I.M.: Character Theory of Finite Groups. Academic Press [Harcourt Brace Jovanovich, Publishers], New York-London (1976). Pure and Applied Mathematics, No. 69
Jespers, E., del Río, Á.: Group Ring Groups. Volume 1: Orders and Generic Constructions of Units. De Gruyter, Berlin (2016)
Kimmerle, W.: On the prime graph of the unit group of integral group rings of finite groups. In: Groups, Rings and Algebras, Contemp. Math., vol. 420, pp. 215–228. Amer. Math. Soc., Providence (2006)
Kimmerle, W., Konovalov, A.: On the Gruenberg-Kegel graph of integral group rings of finite groups. Internat. J. Algebra Comput. 27(6), 619–631 (2017)
Luthar, I.S., Passi, I.B.S.: Zassenhaus conjecture for A 5. Proc. Indian Acad. Sci. Math. Sci. 99(1), 1–5 (1989)
Macdonald, I.: Symmetric Functions and Hall Polynomials, 2nd edn. Oxford Mathematical Monographs. The Clarendon Press, Oxford University Press, New York (1995). With contributions by A. Zelevinsky, Oxford Science Publications
Marciniak, Z., Ritter, J., Sehgal, S., Weiss, A.: Torsion units in integral group rings of some metabelian groups. II. J. Number Theory 25(3), 340–352 (1987)
Margolis, L.: Torsionsuntergruppen in ganzzahligen Gruppenringen nicht auflösbarer Gruppen. Doktorarbeit, Universität Stuttgart http://elib.uni-stuttgart.de/opus/volltexte/2015/10270/ (2015)
Margolis, L.: A Sylow theorem for the integral group ring of PSL(2,q). J. Algebra 445, 295–306 (2016)
Mazurov, V, Khukhro, E.: Unsolved problems in Group Theory. The Kourovka Notebook. No. 18 (english version). arXiv:1401.0300v6 [math.GR] (2015)
Navarro, G.: Characters and Blocks of Finite Groups London Mathematical Society Lecture Note Series, vol. 250. Cambridge University Press, Cambridge (1998)
Neukirch, J.: Algebraic number theory Die Grundlehren der Mathematischen Wissenschaften, vol. 322. Springer-Verlag, Berlin (1999)
del Río, Á., Serrano, M.: On the torsion units of the integral group ring of finite projective special linear groups. Comm. Algebra 45(12), 5073–5087 (2017)
Sandling, R.: Graham Higman’s thesis “Units in group rings”. In: Integral Representations and Applications (Oberwolfach, 1980), Lecture Notes in Math., vol. 882, pp. 93–116. Springer, Berlin-New York (1981)
Weiss, A.: Torsion units in integral group rings. J. Reine Angew. Math. 415, 175–187 (1991)
Acknowledgements
We are very thankful to Markus Schmidmeier for providing us with the link between Littlewood-Richardson coefficients and the structure of finite \(\mathfrak {o}\)-modules.
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Presented by: Steffen Koenig
The first author is supported by the Research Foundation Flanders (FWO - Vlaanderen). The second by the Marie-Curie Individual Fellowship ZC-DLV-705112 from the H2020 program of the European Commission.
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Bächle, A., Margolis, L. On the Prime Graph Question for Integral Group Rings of 4-Primary Groups II. Algebr Represent Theor 22, 437–457 (2019). https://doi.org/10.1007/s10468-018-9776-6
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DOI: https://doi.org/10.1007/s10468-018-9776-6
Keywords
- Integral group ring
- Torsion units
- Zassenhaus conjecture
- Prime graph question
- Littlewood-Richardson coefficient
- Almost simple groups