engleski

Extending the Prym map to toroidal compactifications of the moduli space of abelian varieties

The main purpose of this paper is to present a conceptual approach to understanding the extension of the Prym map from the space of admissible covers of stable curves to different toroidal compatifications of the moduli space of principally polarized abelian varieties. By separating the combinatorial problems from the geometric aspects we can reduce this to the computation of certain monodromy cones. In this way we not only shed new light on the extension results of Alexeev, Birkenhake, Hulek, and Vologodsky for the second Voronoi toroidal compactification, but we also apply this to other toroidal compactfications, in particular the perfect cone compactification, for which we obtain a combinatorial characterization of the indeterminacy locus, as well as a geometric description up to codimension five and an explicit toroidal resolution of the Prym map up to codimension three.

Moduli ; Prym varieties ; Period maps ; Abelian varieties

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