Summary:

Curves and abelian varieties are among the most important examples of algebraic varieties. In complex algebraic geometry, they are very well understood and are used extensively to study more complicated varieties, while in arithmetic geometry, they are an almost endless source of deep theorems and wide open conjectures.

The goal of this course is to explain how curves and abelian varieties naturally degenerate in one-dimensional families. This is an important topic on its own, for instance for the formulation and study of the Birch-Swinnerton-Dyer conjecture, and also a first step towards the general theory of moduli of curves and abelian varieties.

More precisely, given a curve or an abelian variety over a local or global field, we will establish

- the existence of the minimal regular model of the curve,

- the existence of the Néron model of the abelian variety,

- the relationship between the minimal regular model of a curve and

- the Néron model of its Jacobian,

- the stable reduction theorem for curves, and

- the semi-abelian reduction theorem of abelian varieties.

Along the way, we will encounter many basic tools of algebraic geometry: resolution of singularities of surfaces, intersection theory on surfaces, dualizing complexes, the Picard functor, rigid analytic geometry of curves, ...