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The projective extensions of a finite group

Published online by Cambridge University Press:  24 October 2008

P. J. Webb
P. J. Webb
Affiliation:
Department of Pure Mathematics and Mathematical Statistics, University of Cambridge
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Extract

Let G be a finite group and let g be the augmentation ideal of the integral group ring G. Following Gruenberg(5) we let (g̱) denote the category whose objects are short exact sequences of zG-modules of the form and in which the morphisms are commutative diagrams

In this paper we describe the projective objects in this category. These are the objects which satisfy the usual categorical definition of projectivity, but they may also be characterized as the short exact sequences

in which P is a projective module.

Type
Research Article
Information
Mathematical Proceedings of the Cambridge Philosophical Society , Volume 90 , Issue 2 , September 1981 , pp. 251 - 257
Copyright
Copyright © Cambridge Philosophical Society 1981

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