The defect of weak approximation for homogeneous spaces. II

dc.creatorBorovoi, Mikhail
dc.date2008-04-30
dc.date2008-05-10
dc.date.accessioned2026-07-07T09:37:49Z
dc.date.available2026-07-07T09:37:49Z
dc.descriptionLet X be a homogeneous space of a connected linear algebraic group G' over a number field k, containing a k-point x. Assume that the stabilizer of x in G' is connected. Using the notion of a quasi-trivial group, recently introduced by Colliot-Thélène, we can represent X in the form X=G/H, where G is a quasi-trivial k-group and H is a connected k-subgroup of G. Let S be a finite set of places of k. Applying results of [B2], we compute the defect of weak approximation for X with respect to S in terms of the biggest toric quotient T of H. In particular, we show that if T splits over a metacyclic extension of k, then X has the weak approximation property. We show also that any homogeneous space X with connected stabilizer (without assumptions on T) has the real approximation property.
dc.description10 pages. A section on metacyclic extensions is added
dc.identifierhttps://arxiv.org/abs/0804.4767
dc.identifierhttp://arxiv.org/abs/0804.4767
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/160595
dc.subjectNumber Theory
dc.subjectAlgebraic Geometry
dc.subject14G05, 11E72
dc.titleThe defect of weak approximation for homogeneous spaces. II
dc.typetext

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