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Main Authors: Chen, Jungkai, Lee, Yongnam, Soo, Phin-Sing
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2604.26691
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author Chen, Jungkai
Lee, Yongnam
Soo, Phin-Sing
author_facet Chen, Jungkai
Lee, Yongnam
Soo, Phin-Sing
contents Motivated by DeVleming's work on moduli of surfaces in $\mathbb{P}^3$ and Chen-Hu-Jiang's work on moduli of threefolds with volume $2$ and geometric genus $4$, we study the deformation of pairs of $\mathbb{P}^3$ and hypersurfaces using the classification of $\mathbb{Q}$-Gorenstein degenerations of $\mathbb{P}^3$ with canonical singularities. We prove that if a degenerating threefold has canonical singularities, then the moduli space is smooth at the corresponding pair. Consequently, we find some boundary divisors of the moduli of smooth hypersurfaces. Finally, using the double cover method, we derive some information on the moduli space of threefolds $X$ with canonical singularities with the same volume and geometric genus as a double cover of $\mathbb{P}^3$ branched over a hypersurface.
format Preprint
id arxiv_https___arxiv_org_abs_2604_26691
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Deformation of pairs of $\mathbb{P}^3$ and hypersurfaces
Chen, Jungkai
Lee, Yongnam
Soo, Phin-Sing
Algebraic Geometry
14J30
Motivated by DeVleming's work on moduli of surfaces in $\mathbb{P}^3$ and Chen-Hu-Jiang's work on moduli of threefolds with volume $2$ and geometric genus $4$, we study the deformation of pairs of $\mathbb{P}^3$ and hypersurfaces using the classification of $\mathbb{Q}$-Gorenstein degenerations of $\mathbb{P}^3$ with canonical singularities. We prove that if a degenerating threefold has canonical singularities, then the moduli space is smooth at the corresponding pair. Consequently, we find some boundary divisors of the moduli of smooth hypersurfaces. Finally, using the double cover method, we derive some information on the moduli space of threefolds $X$ with canonical singularities with the same volume and geometric genus as a double cover of $\mathbb{P}^3$ branched over a hypersurface.
title Deformation of pairs of $\mathbb{P}^3$ and hypersurfaces
topic Algebraic Geometry
14J30
url https://arxiv.org/abs/2604.26691