Cohomogeneity one solitons for the isometric flow of $G_2$-structures

Fuente: arXiv
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Autores principales: Ivey, Thomas A., Karigiannis, Spiro
Formato: Preprint
Publicado: 2024
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author Ivey, Thomas A.
Karigiannis, Spiro
author_facet Ivey, Thomas A.
Karigiannis, Spiro
contents We consider the existence of cohomogeneity one solitons for the isometric flow of $G_2$-structures on the following classes of torsion-free $G_2$-manifolds: the Euclidean $R^7$ with its standard $G_2$-structure, metric cylinders over Calabi-Yau 3-folds, metric cones over nearly Kähler 6-manifolds, and the Bryant-Salamon $G_2$-manifolds. In all cases we establish existence of global solutions to the isometric soliton equations, and determine the asymptotic behaviour of the torsion. In particular, existence of shrinking isometric solitons on $R^7$ is proved, giving support to the likely existence of type I singularities for the isometric flow. In each case, the study of the soliton equation reduces to a particular nonlinear ODE with a regular singular point, for which we provide a careful analysis. Finally, to simplify the derivation of the relevant equations in each case, we first establish several useful Riemannian geometric formulas for a general class of cohomogeneity one metrics on total spaces of vector bundles which should have much wider application, as such metrics arise often as explicit examples of special holonomy metrics.
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id arxiv_https___arxiv_org_abs_2402_01420
institution arXiv
publishDate 2024
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spellingShingle Cohomogeneity one solitons for the isometric flow of $G_2$-structures
Ivey, Thomas A.
Karigiannis, Spiro
Differential Geometry
53C25, 53C29, 53E99, 58J60
We consider the existence of cohomogeneity one solitons for the isometric flow of $G_2$-structures on the following classes of torsion-free $G_2$-manifolds: the Euclidean $R^7$ with its standard $G_2$-structure, metric cylinders over Calabi-Yau 3-folds, metric cones over nearly Kähler 6-manifolds, and the Bryant-Salamon $G_2$-manifolds. In all cases we establish existence of global solutions to the isometric soliton equations, and determine the asymptotic behaviour of the torsion. In particular, existence of shrinking isometric solitons on $R^7$ is proved, giving support to the likely existence of type I singularities for the isometric flow. In each case, the study of the soliton equation reduces to a particular nonlinear ODE with a regular singular point, for which we provide a careful analysis. Finally, to simplify the derivation of the relevant equations in each case, we first establish several useful Riemannian geometric formulas for a general class of cohomogeneity one metrics on total spaces of vector bundles which should have much wider application, as such metrics arise often as explicit examples of special holonomy metrics.
title Cohomogeneity one solitons for the isometric flow of $G_2$-structures
topic Differential Geometry
53C25, 53C29, 53E99, 58J60
url https://arxiv.org/abs/2402.01420