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arXiv · 2407.10924

Moduli of finite flat torsors over nodal curves

Sara Mehidi·Thibault Poiret
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Abstract

We show that log flat torsors over a family $X/S$ of nodal curves under a finite flat commutative group scheme $G/S$ are classified by maps from the Cartier dual of $G$ to the log Jacobian of $X$. We deduce that fppf torsors on the smooth fibres of $X/S$ can be extended to global log flat torsors under some regularity hypotheses.

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Sara Mehidi, Thibault Poiret. 2025-06-26. Moduli of finite flat torsors over nodal curves. https://arxiv.org/abs/2407.10924

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