PreprintCC BY 4.0arXiv
Deformations, local freeness, and base change for higher Du Bois singularities
Abstract
We prove that strict higher Du Bois singularities are invariant under small deformations. Using this, we prove a base change theorem for the relative Du Bois complex with strict higher Du Bois fibers, answering a question of Kovács--Taji. We exhibit failures of deformation invariance and base change for $1$-Du Bois fibers, showing that the strictness condition is essentially sharp. We also generalize the local-freeness theorem of Friedman--Laza beyond the local complete intersection setting for families over an arbitrary base, and show the unobstructedness of deformations of strict-$1$-Du Bois canonical Calabi-Yau varieties.
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BibTeX
@misc{ning2026deformations,
title = {{Deformations, local freeness, and base change for higher Du Bois singularities}},
author = {Haoming Ning},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2608.07849},
eprint = {2608.07849},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2608.07849},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Deformations, local freeness, and base change for higher Du Bois singularities
AU - Haoming Ning
PY - 2026
DA - 2026/10/07
PB - arXiv
DO - 10.48550/arxiv.2608.07849
UR - https://arxiv.org/abs/2608.07849
AB - We prove that strict higher Du Bois singularities are invariant under small deformations. Using this, we prove a base change theorem for the relative Du Bois complex with strict higher Du Bois fibers, answering a question of Kovács--Taji. We exhibit failures of deformation invariance and base change for $1$-Du Bois fibers, showing that the strictness condition is essentially sharp. We also generalize the local-freeness theorem of Friedman--Laza beyond the local complete intersection setting for families over an arbitrary base, and show the unobstructedness of deformations of strict-$1$-Du Bois canonical Calabi-Yau varieties.
ER -