Weil Classes and Decomposable Abelian Fourfolds

We determine which codimension two Hodge classes on × , where is a general abelian surface, deform to Hodge classes on a family of abelian fourfolds of Weil type. If a Hodge class deforms, there is, in general, a unique such family. We show how to determine the imaginary quadratic field acting on...

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Veröffentlicht in:Symmetry, Integrability and Geometry: Methods and Applications
Datum:2022
ISSN:1815-0659
1. Verfasser: van Geemen, Bert
Format: Artikel
Sprache:Englisch
Veröffentlicht: Інститут математики НАН України 2022
Online Zugang:https://nasplib.isofts.kiev.ua/handle/123456789/211807
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Назва журналу:Digital Library of Periodicals of National Academy of Sciences of Ukraine
Zitieren:Weil Classes and Decomposable Abelian Fourfolds. Bert van Geemen. SIGMA 18 (2022), 097, 18 pages

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Digital Library of Periodicals of National Academy of Sciences of Ukraine
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Zusammenfassung:We determine which codimension two Hodge classes on × , where is a general abelian surface, deform to Hodge classes on a family of abelian fourfolds of Weil type. If a Hodge class deforms, there is, in general, a unique such family. We show how to determine the imaginary quadratic field acting on the fourfolds of Weil type in this family, as well as their polarization. There are Hodge classes that may deform to more than one family. We relate these to Markman's Cayley classes.
ISSN:1815-0659