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arXiv · 1601.06907

Subadditivity of Kodaira dimensions for fibrations of three-folds in positive characteristics

Lei Zhang
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Abstract

In this paper, we will prove subadditivity of Kodaira dimensions for a fibration with possibly singular geometric generic fiber, under certain nefness and relative semi-ampleness conditions. As an application, for a fibration $f: X \to Y$ of a smooth projective threefold over an algebraically closed field of characteristic $p>5$, under the assumption that $Y$ is of general type and non-uniruled, we prove subadditivity of Kodaira dimensions when general fibers are smooth or when $K_{X/Y}$ is relatively big over $Y$.

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Lei Zhang. 2016-01-26. Subadditivity of Kodaira dimensions for fibrations of three-folds in positive characteristics. https://arxiv.org/abs/1601.06907

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