Weil Classes and Decomposable Abelian Fourfolds

• Veröffentlicht in: Symmetry, Integrability and Geometry: Methods and Applications
• Datum: 2022
• 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
• 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

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...