A zero theorem for the transfer of coherent Witt groups, by Stefan Gille and Jens Hornbostel

Let R be a Gorenstein ring of finite Krull dimension and t a regular element of R. We show that if the quotient map R --> R/Rt has a flat splitting then the transfer map of coherent Witt groups induced by this quotient map is zero. As an application we give another proof of the Gersten conjecture for Witt groups in the case of regular semilocal rings essentially of finite type over a field of characteristic not 2.


Stefan Gille <gilles@math.uni-muenster.de>
Jens Hornbostel <jens.hornbostel@mathematik.uni-regensburg.de>