Fields of definition of building blocks with quaternionic multiplication

This paper investigates the fields of definition up to isogeny of the abelian varieties called building blocks. In [Ri1] and $[\mathrm{Py}]$ a characterization of the fields of definition of these varieties together with their endomorphisms is given in terms of a Galois cohomology class canonically...

Full description

Bibliographic Details
Author: Guitart Morales, Xavier
Format: article
Status:Versión aceptada para publicación
Publication Date:2012
Country:España
Institution:Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)
Repository:Recercat. Dipósit de la Recerca de Catalunya
OAI Identifier:oai:recercat.cat:2445/193368
Online Access:https://hdl.handle.net/2445/193368
Access Level:Open access
Keyword:Teoria de nombres
Geometria algebraica aritmètica
Varietats de Shimura
Aritmètica
Number theory
Arithmetical algebraic geometry
Shimura varieties
Arithmetic
Description
Summary:This paper investigates the fields of definition up to isogeny of the abelian varieties called building blocks. In [Ri1] and $[\mathrm{Py}]$ a characterization of the fields of definition of these varieties together with their endomorphisms is given in terms of a Galois cohomology class canonically attached to them. However, when the building blocks have quaternionic multiplication, then the field of definition of the varieties can be strictly smaller than the field of definition of their endomorphisms. What we do is to give a characterization of the field of definition of the varieties in this case (also in terms of their associated Galois cohomology class), and we also make the computations that are needed in order to calculate in practice these fields from our characterization.