Almost Parallel Structures

Simon Salamon

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Almost Parallel Structures

Simon Salamon

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Abstract

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.

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Simon Salamon. 2001-07-20. Almost Parallel Structures. https://arxiv.org/abs/math/0107146

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