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On the determination of the ramification index in Clifford's theorem

Published online by Cambridge University Press:  13 July 2011

Robert W. van der Waall
Robert W. van der Waall
Affiliation:
Mathematisch InstituutUniversiteit van AmsterdamRoetersstraat 151018 WB Amsterdam, The Netherlands
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Let K be a field, G a finite group, V a (right) KG-module. If H is a subgroup of G, then, restricting the action of G on V to H, V is also a KH-module. Notation: VH.

Suppose N is a normal subgroup of G. The KN-module VN is not irreducible in general, even when V is irreducible as KG-module. A part of the well-known theorem of A. H. Clifford [1, V.17.3] yields the following.

Type
Research Article
Information
Proceedings of the Edinburgh Mathematical Society , Volume 31 , Issue 3 , October 1988 , pp. 469 - 474
Copyright
Copyright © Edinburgh Mathematical Society 1988

References

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