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arXiv · 1004.3090

An Improvement of de Jong-Oort's Purity Theorem

Yanhong Yang
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Abstract

Consider an $F$-crystal over a noetherian scheme $S$. De Jong--Oort's purity theorem states that the associated Newton polygons over all points of $S$ are constant if this is true outside a subset of codimension bigger than 1. In this paper we show an improvement of the theorem, which says that the Newton polygons over all points of $S$ have a common break point if this is true outside a subset of codimension bigger than 1.

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Yanhong Yang. 2010-04-19. An Improvement of de Jong-Oort's Purity Theorem. https://arxiv.org/abs/1004.3090

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