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The stack of Potts curves and its fibre at a prime of wild ramification

Matthieu Romagny
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Abstract

In this article we study the modular properties of a family of cyclic coverings of P^1 of degree N, in all odd characteristics. We compute the moduli space of the corresponding algebraic stack over Z[1/2], as well as the Picard groups over algebraically closed fields. We put special emphasis on the study of the fibre of the stack at a prime of wild ramification; in particular we show that the moduli space has good reduction at such a prime.

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Matthieu Romagny. 2003-05-18. The stack of Potts curves and its fibre at a prime of wild ramification. https://arxiv.org/abs/math/0201297

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