Derived Witt groups of a scheme, by Paul Balmer

We define the derived Witt groups of a scheme using derived categories. We establish an isomorphism between the usual Witt group of a ring and its derived Witt group. This new approach is used for some questions of localization. We give a new conceptual proof of purity in dimension 3.


Paul Balmer <paul.balmer@ima.unil.ch>