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Main Author: Park, Hyeonjun
Format: Preprint
Published: 2024
Subjects:
Online Access:https://arxiv.org/abs/2406.19192
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author Park, Hyeonjun
author_facet Park, Hyeonjun
contents We introduce how to pushforward shifted symplectic fibrations along base changes. This is achieved by considering symplectic forms that are closed in a stronger sense. Examples include: symplectic zero loci and symplectic quotients. Observing that twisted cotangent bundles are symplectic pushforwards, we obtain an equivalence between symplectic fibrations and Lagrangians to critical loci. We provide two local structure theorems for symplectic fibrations: a smooth local structure theorem for higher stacks via symplectic zero loci and twisted cotangents, and an {é}tale local structure theorem for $1$-stacks with reductive stabilizers via symplectic quotients of the smooth local models. We resolve deformation invariance issue in Donaldson-Thomas theory of Calabi-Yau $4$-folds. Abstractly, we associate virtual Lagrangian cycles for oriented $(-2)$-symplectic fibrations as unique functorial bivariant classes over the exact loci. For moduli of perfect complexes, we show that the exact loci consist of deformations for which the $(0,4)$-Hodge pieces of the second Chern characters remain zero.
format Preprint
id arxiv_https___arxiv_org_abs_2406_19192
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Shifted symplectic pushforwards
Park, Hyeonjun
Algebraic Geometry
We introduce how to pushforward shifted symplectic fibrations along base changes. This is achieved by considering symplectic forms that are closed in a stronger sense. Examples include: symplectic zero loci and symplectic quotients. Observing that twisted cotangent bundles are symplectic pushforwards, we obtain an equivalence between symplectic fibrations and Lagrangians to critical loci. We provide two local structure theorems for symplectic fibrations: a smooth local structure theorem for higher stacks via symplectic zero loci and twisted cotangents, and an {é}tale local structure theorem for $1$-stacks with reductive stabilizers via symplectic quotients of the smooth local models. We resolve deformation invariance issue in Donaldson-Thomas theory of Calabi-Yau $4$-folds. Abstractly, we associate virtual Lagrangian cycles for oriented $(-2)$-symplectic fibrations as unique functorial bivariant classes over the exact loci. For moduli of perfect complexes, we show that the exact loci consist of deformations for which the $(0,4)$-Hodge pieces of the second Chern characters remain zero.
title Shifted symplectic pushforwards
topic Algebraic Geometry
url https://arxiv.org/abs/2406.19192