Effective models and extension of torsors over a discrete valuation ring of unequal characteristic

dc.creatorTossici, Dajano
dc.date2008-03-26
dc.date2008-10-19
dc.date.accessioned2026-07-07T10:10:50Z
dc.date.available2026-07-07T10:10:50Z
dc.descriptionLet R be a discrete valuation ring of unequal characteristic with fraction field K which contains a primitive p^2-th root of unity. Let X be a faithfully flat R-scheme and G be a finite abstract group. Let us consider a G-torsor Y_K\to X_K and let Y be the normalization of X_K in Y. If G=Z/p^n Z, n<3, under some hypothesis on X, we attach some invariants to Y_K \to X_K. If p>2, we determine, through these invariants, when Y\to X has a structure of torsor which extends that of Y_K\to X_K. Moreover we explicitly calculate the effective model (defined by Romagny) of the action of G on Y.
dc.description40 pages, final version, corrected and improved some statements in the sections 4,5,6 and 7
dc.identifierhttps://arxiv.org/abs/0803.3730
dc.identifierhttp://arxiv.org/abs/0803.3730
dc.identifierInternat. Math. Res. Not. (2008); Vol. 2008, article ID:rnn111, 68 pages
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/171706
dc.subjectAlgebraic Geometry
dc.subjectNumber Theory
dc.subject14L15; 14L30; 11G25
dc.titleEffective models and extension of torsors over a discrete valuation ring of unequal characteristic
dc.typetext

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