The Néron component series of a degenerating family of abelian varieties

Abstract: Let K be a complete discretely valued field and let A be an abelian K-variety. In this talk I will discuss the Néron component series of A. This is a formal power series in Z[[T]] which measures how the number of connected components of the special fiber of the Néron model of A varies under tame extensions of A.

In case A is wildly ramified, it is particularly challenging to describe the properties of this series. I will present some results for Jacobians and abelian varieties with potential multiplicative reduction, and discuss a few open problems in this setting.

This is joint work with Johannes Nicaise.