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Bibliographic Details
Main Author: Platt, Daniel
Format: Preprint
Published: 2020
Subjects:
Online Access:https://arxiv.org/abs/2011.00482
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author Platt, Daniel
author_facet Platt, Daniel
contents The resolution of the $G_2$-orbifold $T^7/Γ$, where $Γ$ is a suitably chosen finite group, admits a $1$-parameter family of $G_2$-structures with small torsion $φ^t$, obtained by gluing in Eguchi-Hanson spaces. It was shown by Joyce that $φ^t$ can be perturbed to torsion-free $G_2$-structures $\tildeφ^t$ for small values of $t$. Using norms adapted to the geometry of the manifold we give an alternative proof of the existence of $\tildeφ^t$. This alternative proof produces the estimate $\left|\left| \tildeφ^t-φ^t \right|\right|_{C^0} \leq ct^{5/2}$. This is an improvement over the previously known estimate $\left|\left| \tildeφ^t-φ^t \right|\right|_{C^0} \leq ct^{1/2}$. As part of the proof, we show that Eguchi-Hanson space admits a unique (up to scaling) harmonic form with decay, which is a result of independent interest.
format Preprint
id arxiv_https___arxiv_org_abs_2011_00482
institution arXiv
publishDate 2020
record_format arxiv
spellingShingle Improved Estimates for $G_2$-structures on the Generalised Kummer Construction
Platt, Daniel
Differential Geometry
53C29 (Primary), 35J60 (Secondary)
The resolution of the $G_2$-orbifold $T^7/Γ$, where $Γ$ is a suitably chosen finite group, admits a $1$-parameter family of $G_2$-structures with small torsion $φ^t$, obtained by gluing in Eguchi-Hanson spaces. It was shown by Joyce that $φ^t$ can be perturbed to torsion-free $G_2$-structures $\tildeφ^t$ for small values of $t$. Using norms adapted to the geometry of the manifold we give an alternative proof of the existence of $\tildeφ^t$. This alternative proof produces the estimate $\left|\left| \tildeφ^t-φ^t \right|\right|_{C^0} \leq ct^{5/2}$. This is an improvement over the previously known estimate $\left|\left| \tildeφ^t-φ^t \right|\right|_{C^0} \leq ct^{1/2}$. As part of the proof, we show that Eguchi-Hanson space admits a unique (up to scaling) harmonic form with decay, which is a result of independent interest.
title Improved Estimates for $G_2$-structures on the Generalised Kummer Construction
topic Differential Geometry
53C29 (Primary), 35J60 (Secondary)
url https://arxiv.org/abs/2011.00482