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Normal Fitting classes and Hall subgroups

Published online by Cambridge University Press:  17 April 2009

Elspeth Cusack
Affiliation:
School of Mathematics and Physics, University of East Anglia, Norwich, England.
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Abstract

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It was shown by Bryce and Cossey that each Hall π-subgroup of a group in the smallest normal Fitting class S* necessarily lies in S*, for each set of primes π. We prove here that for each set of primes π such that |π| ≥ 2 and π′ is not empty, there exists a normal Fitting class without this closure property. A characterisation is obtained of all normal Fitting classes which do have this property.

Let F be a normal Fitting class closed under taking Hall π-subgroups, in the sense of the paragraph above, and let Sπ denote the Fitting class of all finite soluble π-groups, for some set of primes π. The second main theorem is a characterisation of the groups in the smallest Fitting class containing F and Sπ in terms of their Hall π-subgroups.

Type
Research Article
Copyright
Copyright © Australian Mathematical Society 1980

References

[1]Beidleman, James C. und Hauck, Peter, “Über Fittingklassen und die Lockett-Vermutung”, submitted.Google Scholar
[2]Berger, Thomas R., “More normal Fitting classes of finite solvable groups”, Math. Z. 151 (1976), 13.Google Scholar
[3]Blessenohl, Dieter und Gaschütz, Wolfgang, “Über normale Schunk– und Fittingklassen”, Math. Z. 118 (1970), 18.Google Scholar
[4]Brison, Owen John, “On the theory of Fitting classes of finite groups” (PhD thesis, University of Warwick, Warwick, 1978).Google Scholar
[5]Bryant, R.M. and Kovács, L.G., “Lie representations and groups of prime power order”, J. London Math. Soc. (2) 17 (1978), 415421.Google Scholar
[6]Bryce, R.A. and Cossey, John, “A problem in the theory of normal Fitting classes”, Math. Z. 141 (1975), 99110.Google Scholar
[7]Cusack, Elspeth, “The join of two Fitting classes”, Math. Z. 167 (1979), 3747.Google Scholar
[8]Hauck, Peter, “Zur Theorie der Fittingklassen endlicher auflosbarer” (PhD thesis, Johannes Gutenberg-Universität in Mainz, Mainz, Germany, 1977).Google Scholar
[9]Laue, Harmut, Lausch, Hans und Pain, Garry R., “Verlagerung und normale Fittingklassen endlichen Gruppen”, Math. Z. 154 (1977), 257260.Google Scholar
[10]Lockett, F. Peter, “The Fitting class ”, Math. 1. 137 (1974), 131136.CrossRefGoogle Scholar