On quadratically enriched excess and residual intersections

Abstract

We use recent duality results of Eisenbud--Ulrich to give tools to study quadratically enriched residual intersections when there is no excess bundle. We use this to prove a formula for the Witt-valued Euler number of an almost complete intersection. We give example computations of quadratically enriched excess and residual intersections.

arXiv comment32 pages. Accepted for publication in Journal für die reine und angewandte Mathematik (Crelle's Journal)