ArticleOriginal scientific textOn double covers of the generalized alternating group
Title
On double covers of the generalized alternating group as Galois groups over algebraic number fields
Authors 1
Affiliations
- Fb Mathematik, Universität-Gesamthochschule Paderborn, D-33095 Paderborn, Germany
Abstract
Let be the generalized alternating group. We prove that all double covers of occur as Galois groups over any algebraic number field. We further realize some of these double covers as the Galois groups of regular extensions of ℚ(T). If d is odd and m >7, then every central extension of occurs as the Galois group of a regular extension of ℚ(T). We further improve some of our earlier results concerning double covers of the generalized symmetric group .
Bibliography
- K. S. Brown, Cohomology of Groups, Grad. Texts in Math. 87, Springer, New York, 1982.
- M. Epkenhans, On the Galois group of
, Comm. Algebra, to appear. - M. Epkenhans, Trace forms of trinomials, J. Algebra 155 (1993), 211-220.
- M. Epkenhans, On double covers of the generalized symmetric group
as Galois groups over algebraic number fields K with , J. Algebra 163 (1994), 404-423. - B. Huppert, Endliche Gruppen I, Grundlehren Math. Wiss. 137, Springer, Berlin, 1967.
- M. Ikeda, Zur Existenz eigentlicher galoisscher Körper beim Einbettungsproblem für galoissche Algebren, Abh. Math. Sem. Univ. Hamburg 24 (1960), 126-131.
- G. Karpilovsky, The Schur Multiplier, London Math. Soc. Monographs (N.S.), Clarendon Press, London, 1987.
- D. Kotlar, M. Schacher and J. Sonn, Central extension of symmetric groups as Galois groups, J. Algebra 124 (1989), 183-198.
- S. Lang, Introduction to Algebraic Geometry, Addison-Wesley, 1972.
- B. H. Matzat, Konstruktive Galoistheorie, Lecture Notes in Math. 1284, Springer, Berlin, 1987.
- J. F. Mestre, Extensions régulières de ℚ(T) de groupe de Galois
, J. Algebra 131 (1990), 483-495. - O. T. O'Meara, Introduction to Quadratic Forms, Springer, Berlin, 1963.
- M. Schacher and J. Sonn, Double covers of the symmetric groups as Galois groups over number fields, J. Algebra 116 (1988), 243-250.
- J. P. Serre, Corps Locaux, Hermann, Paris, 1968.
- J. P. Serre, L'invariant de Witt de la forme
, Comment. Math. Helv. 59 (1984), 651-676. - J. P. Serre, Topics in Galois Theory, 1, Res. Notes in Math. 1, Jones and Bartlett, Boston, 1992.
- J. Sonn, Central extensions of
as Galois groups via trinomials, J. Algebra 125 (1989), 320-330. - J. Sonn, Central extensions of S_n as Galois groups of regular extensions of ℚ(T), J. Algebra 140 (1991), 355-359.
- N. Vila, On central extensions of
as Galois group over ℚ, Arch. Math. (Basel) 44 (1985), 424-437. - N. Vila, On stem extensions of
as Galois group over number fields, J. Algebra 116 (1988), 251-260. - H. Völklein, Central extensions as Galois groups, J. Algebra 146 (1992), 144-152.