On the rationality problem for quadric bundles
arXiv:1706.01356 · doi:10.1215/00127094-2018-0041
Abstract
We classify all positive integers n and r such that (stably) non-rational complex r-fold quadric bundles over rational n-folds exist. We show in particular that for any n and r, a wide class of smooth r-fold quadric bundles over projective n-space are not stably rational if r lies in the interval from to . In our proofs we introduce a generalization of the specialization method of Voisin and Colliot-Thélène--Pirutka which avoids universally -trivial resolutions of singularities.
31 pages; final version; to appear in Duke Math. Journal