Homology pp 358-403 | Cite as

Derived Functors

  • Saunders Mac Lane
Part of the Classics in Mathematics book series (volume 114)


This chapter will place our previous developments in a more general setting. Fitrs, we have already noted that modules may be replaced by objects in an abelian category; our first three sections develop this technique and show how those ideas of homological algebra which do not involve tensor products can be carried over to any abelian category. Second, the relative and the absolute Ext functors can be treated to-gether, as cases of the general theory of “proper” exact sequences developed here in §§4–7. The next sections describe the process of forming “derived” functors: Hom R leads to the functors Ext R n , ⊗ R to the Tor n R , and any additive functor T to a sequence of “satellite” functors. Finally, an application of these ideas to the category of complexes yields a generalized KÜNNETH formula in which the usual exact sequence is replaced by a spectral sequence.


Abelian Group Exact Sequence Spectral Sequence Short Exact Sequence Natural Transformation 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Copyright information

© Springer-Verlag Berlin Heidelberg 1995

Authors and Affiliations

  • Saunders Mac Lane
    • 1
  1. 1.Department of MathematicsUniversity of ChicagoChicagoUSA

Personalised recommendations