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Non-vanishing of the structure-sheaf cohomology of affine henselian schemes and henselian affinoids
Abstract
Let (A,I) be a henselian pair such that A is a domain of characteristic zero and I≠0. We prove that any flat affine henselian scheme of finite presentation over (A,I) has nonzero first structure-sheaf cohomology whenever one of its fibers over a point in V(I) has positive dimension. This in particular gives a negative answer to the question by Devadas in the mixed-characteristic case. As an application, we also prove that the first structure-sheaf cohomology does not vanish for henselian affinoids of positive dimensions.
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BibTeX
@misc{gongyo2026nonvanishing,
title = {{Non-vanishing of the structure-sheaf cohomology of affine henselian schemes and henselian affinoids}},
author = {Yoshinori Gongyo and Fumiharu Kato and Takayuki Uchiba},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.30851},
eprint = {2609.30851},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.30851},
}
RIS
TY - UNPB
TI - Non-vanishing of the structure-sheaf cohomology of affine henselian schemes and henselian affinoids
AU - Yoshinori Gongyo
AU - Fumiharu Kato
AU - Takayuki Uchiba
PY - 2026
DA - 2026/09/25
PB - arXiv
DO - 10.48550/arxiv.2609.30851
UR - https://arxiv.org/abs/2609.30851
AB - Let (A,I) be a henselian pair such that A is a domain of characteristic zero and I≠0. We prove that any flat affine henselian scheme of finite presentation over (A,I) has nonzero first structure-sheaf cohomology whenever one of its fibers over a point in V(I) has positive dimension. This in particular gives a negative answer to the question by Devadas in the mixed-characteristic case. As an application, we also prove that the first structure-sheaf cohomology does not vanish for henselian affinoids of positive dimensions.
ER -