Almost Parallel Structures
Abstract
Description
A discussion of torsion of Riemannian G-structures leads to a survey of contributions of Alfred Gray and others on almost Hermitian manifolds, G_2-manifolds, curvature identities, volume expansions, plotting geodesics, and the geometry of nilmanifolds. The paper concludes with a new example of a compact 8-manifold with a quaternionic 4-form that is closed but not parallel.
Proceedings, Congress in memory of Alfred Gray, to appear in AMS Contemporary Mathematics
Proceedings, Congress in memory of Alfred Gray, to appear in AMS Contemporary Mathematics