Prym--Tyurin varieties coming from intermediate coverings of curves

Abstract

We introduce a new geometric construction of Prym--Tyurin varieties of odd prime exponent $p$ arising from intermediate coverings of ${\mathbb{Z}}_p\times {\mathbb{Z}}_p$--Galois covers of smooth curves. We determine precisely when these coverings give rise to Prym--Tyurin varieties, namely when the base curve is elliptic and in the case of isotropic étale covers over curves of genus $2$. The explicit nature of the construction makes it possible to analyze the geometry of the associated Prym--Tyurin varieties and to prove that the corresponding Prym--Tyurin maps, indexed by the choice of a generating vector, are generically finite onto their images.

Part of the PhD thesis of the author