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Mathematics 2014
Twisted forms of toric varietiesAbstract: We consider the set of forms of a toric variety over an arbitrary field: those varieties which become isomorphic over a field extension. In contrast to most previous work, we do not necessarily fix a specific torus or its action in advance. We define an injective map from the set of forms of a toric variety to a non-abelian second cohomology set, which generalizes the usual Brauer class of a Severi-Brauer variety. Additionally, we define a map from the set of forms of a toric variety to the set of forms of a separable algebra along similar lines to a construction of A. Merkurjev and I. Panin. This generalizes both a result of M. Blunk for del Pezzo surfaces of degree 6, and the standard bijection between Severi-Brauer varieties and central simple algebras.
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