Grothendieck local duality

(Redirected from Local duality theorem)

In commutative algebra, Grothendieck local duality is a duality theorem for cohomology of modules over local rings, analogous to Serre duality of coherent sheaves.

Statement

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Suppose that R is a Cohen–Macaulay local ring of dimension d with maximal ideal m and residue field k = R/m. Let E(k) be a Matlis module, an injective hull of k, and let Ω be the completion of its dualizing module. Then for any R-module M there is an isomorphism of modules over the completion of R:

 

where Hm is a local cohomology group.

There is a generalization to Noetherian local rings that are not Cohen–Macaulay, that replaces the dualizing module with a dualizing complex.

See also

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References

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  • Bruns, Winfried; Herzog, Jürgen (1993), Cohen–Macaulay rings, Cambridge Studies in Advanced Mathematics, vol. 39, Cambridge University Press, ISBN 978-0-521-41068-7, MR 1251956