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arXiv · 2607.18588

Non-liftable varieties via etale cohomology rings

Runjie Hu·Siqing Zhang
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Abstract

We construct a smooth projective variety in positive characteristic whose $\mathbb{Q}_{\ell}$-coefficient etale cohomology ring is not the scalar extension of any graded $\mathbb{Q}$-algebra, providing an example of a new type of obstruction to characteristic zero liftability.

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Runjie Hu, Siqing Zhang. 2026-07-20. Non-liftable varieties via etale cohomology rings. https://arxiv.org/abs/2607.18588

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