Mathematics – Differential Geometry
Scientific paper
2003-05-08
Proceeding of Gokova Geometry-Topology Conference 2005 edited by S. Akbulut, T Onder, and R.J. Stern (2006), International Pre
Mathematics
Differential Geometry
31 pages, no figures, corrections of various typos and a reorganization of some material to improve clarity. Some new results
Scientific paper
This article consists of some loosely related remarks about the geometry of G_2-structures on 7-manifolds and is partly based on old unpublished joint work with two other people: F. Reese Harvey and Steven Altschuler. Much of this work has since been subsumed in the work of Hitchin \cite{MR02m:53070} and Joyce \cite{MR01k:53093}. I am making it available now mainly because of interest expressed by others in seeing these results written up since they do not seem to have all made it into the literature. A formula is derived for the scalar curvature and Ricci curvature of a G_2-structure in terms of its torsion. When the fundamental 3-form of the G_2-structure is closed, this formula implies, in particular, that the scalar curvature of the underlying metric is nonpositive and vanishes if and only if the structure is torsion-free. This version contains some new results on the pinching of Ricci curvature for metrics associated to closed G_2-structures. Some formulae are derived for closed solutions of the Laplacian flow that specify how various related quantities, such as the torsion and the metric, evolve with the flow. These may be useful in studying convergence or long-time existence for given initial data.
No associations
LandOfFree
Some remarks on G_2-structures does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Some remarks on G_2-structures, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Some remarks on G_2-structures will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-23537