Extensions of Modules

  • F. E. A. JohnsonEmail author
Part of the Algebra and Applications book series (AA, volume 17)


In this chapter we develop the classical theory of module extensions and, in particular, its interpretation in terms of cohomology. As explained in the Introduction, to achieve our intended application it is necessary to avoid injective modules. In consequence a feature of our treatment is the development of the exact sequences of Ext using only projective modules.


Exact Sequence Commutative Diagram Short Exact Sequence Projective Module Projective Resolution 
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Copyright information

© Springer-Verlag London Limited 2012

Authors and Affiliations

  1. 1.Department of MathematicsUniversity College LondonLondonUK

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