Twists of symmetric bundles
| dc.creator | Cassou-Nogues, Ph. | |
| dc.creator | Erez, B. | |
| dc.creator | Taylor, M. J. | |
| dc.date | 2004-04-11 | |
| dc.date.accessioned | 2026-07-07T05:07:22Z | |
| dc.date.available | 2026-07-07T05:07:22Z | |
| dc.description | We establish comparison results between the Hasse-Witt invariants w_t(E) of a symmetric bundle E over a scheme and the invariants of one of its twists E_α. For general twists we describe the difference between w_t(E) and w_t(E_α) up to terms of degree 3. Next we consider a special kind of twist, which has been studied by A. Fröhlich. This arises from twisting by a cocycle obtained from an orthogonal representation. We show how to explicitly describe the twist for representations arising from very general tame actions. This involves the ``square root of the inverse different'' which Serre, Esnault, Kahn, Viehweg and ourselves had studied before. For torsors we show that, in our geometric set-up, Jardine's generalization of Frohlich's formula holds. The case of genuinely tamely ramified actions is geometrically more involved and leads us to introduce a ramification invariant which generalises in higher dimension the invariant introduced by Serre for curves. | |
| dc.description | 58 pages | |
| dc.identifier | https://arxiv.org/abs/math/0404219 | |
| dc.identifier | http://arxiv.org/abs/math/0404219 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/70832 | |
| dc.subject | Algebraic Geometry | |
| dc.subject | Number Theory | |
| dc.subject | 11E70; 14E20 | |
| dc.title | Twists of symmetric bundles | |
| dc.type | text |