Complete families of indecomposable non-simple abelian varieties

Families of Abelian Varieties

Split Reductions of Simple Abelian Varieties

Consider an absolutely simple abelian variety X over a number field K. We show that if the absolute endomorphism ring of X is commutative and satisfies certain parity conditions, then Xp is absolutely simple for almost all primes p. Conversely, if the absolute endomorphism ring of X is noncommutative, then Xp is reducible for p in a set of positive density. An absolutely simple abelian variety ...

Definability of Restricted Theta Functions and Families of Abelian Varieties

We consider some classical maps from the theory of abelian varieties and their moduli spaces, and prove their definability on restricted domains in the o-minimal structure Ran,exp. In particular, we prove that the projective embedding of the moduli space of the principally polarized abelian variety Sp(2g,Z)\Hg is definable in Ran,exp when restricted to Siegel’s fundamental set Fg . We also prov...

Restriction of Sections for Families of Abelian Varieties

Given a family of Abelian varieties over a positive-dimensional base, we prove that for a sufficiently general curve in the base, every rational section of the family over the curve is contained in a unique rational section over the entire base. 1. Main results sec-intro The starting point for this article is the following theorem. Theorem 1.1. [GHMS05, Theorem 6.2] Let B be a smooth, quasi-pro...

Non-Archimedean analytic curves in Abelian varieties

One of the main subtleties of non-Archimedean analysis is that the natural topology that one puts on non-Archimedean analytic spaces is totally disconnected, meaning that there is a base for the topology consisting of sets which are both open and closed. This makes it difficult, for instance, to define a good notion of analytic function so that one has analytic continuation properties. Of cours...