New Inhomogeneous Nearly G2-metric on the Berger Space and a Sine Cone Desingularisation
Abstract
Nearly G2 manifolds are positive Einstein seven-dimensional manifolds whose associated cone metric has special holonomy equal to, or contained in, Spin(7). We study nearly parallel G2-structures invariant under a cohomogeneity-one action of SO(4), and construct the first inhomogeneous nearly parallel G2-structure on the Berger space SO(5)/SO(3). The cone over this metric has full holonomy Spin(7). The existence of the solution is established by a rigorous computer-assisted shooting argument. We also establish a local desingularisation of a finite quotient of the sine cone over S3× S3 by gluing in the asymptotically conical C7 bubble constructed by Foscolo--Haskins--Nordström. We show that as the singular orbit of a family of nearly parallel G2 manifolds collapses, away from the singular orbit the desingularising family converges to the sine cone quotient, while the natural blow-up converges to the AC torsion-free G2-metric of C7.
Related
- Half-space last passage percolation with inhomogeneous first row
- Hardy Space and Exponential Decay of Inhomogeneous Navier-Stokes System in the 2D Global domain
- Dynamic Latent Space Modeling of Inhomogeneous Poisson Network Processes with Applications to International Relations
- Space-time localized nonuniqueness for the inhomogeneous Navier-Stokes equations
- Relaxation of a Vlasov gas to an inhomogeneous state due to phase space mixing in an axisymmetric potential: A Newtonian analogy of the Kerr orbital motion
BibTeX
@misc{salamon2026inhomogeneous,
title = {{New Inhomogeneous Nearly $\mathrmG_2$-metric on the Berger Space and a Sine Cone Desingularisation}},
author = {Simon Salamon and Ragini Singhal},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.37265},
eprint = {2609.37265},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.37265},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - New Inhomogeneous Nearly G_2-metric on the Berger Space and a Sine Cone Desingularisation
AU - Simon Salamon
AU - Ragini Singhal
PY - 2026
DA - 2026/09/29
PB - arXiv
DO - 10.48550/arxiv.2609.37265
UR - https://arxiv.org/abs/2609.37265
AB - Nearly G_2 manifolds are positive Einstein seven-dimensional manifolds whose associated cone metric has special holonomy equal to, or contained in, Spin(7). We study nearly parallel G_2-structures invariant under a cohomogeneity-one action of SO(4), and construct the first inhomogeneous nearly parallel G_2-structure on the Berger space SO(5)/SO(3). The cone over this metric has full holonomy Spin(7). The existence of the solution is established by a rigorous computer-assisted shooting argument. We also establish a local desingularisation of a finite quotient of the sine cone over S^3× S^3 by gluing in the asymptotically conical C_7 bubble constructed by Foscolo--Haskins--Nordström. We show that as the singular orbit of a family of nearly parallel G_2 manifolds collapses, away from the singular orbit the desingularising family converges to the sine cone quotient, while the natural blow-up converges to the AC torsion-free G_2-metric of C_7.
ER -