{ "id": "2212.13811", "version": "v1", "published": "2022-12-28T13:08:37.000Z", "updated": "2022-12-28T13:08:37.000Z", "title": "Intrinsic torsion and scalar curvature of Spin(7)-structure", "authors": [ "Kamil Niedzialomski" ], "comment": "11 pages", "categories": [ "math.DG" ], "abstract": "We obtain explicit formula for the intrinsic torsion of a ${\\rm Spin}(7)$-structure on an $8$--dimensional Riemannian manifold. The formula relates the intrinsic torsion with the Lee form $\\theta$ and $\\Lambda^3_{48}$--component $(\\delta\\Phi)_{48}$ of codifferential $\\delta\\Phi$ of the $4$--form defining given structure. Moreover, using the divergence formula obtained by the author for general Riemannian $G$--structure, we derive the formula for the scalar curvature in terms of norms of $\\theta$, $(\\delta\\Phi)_{48}$ and the divergence ${\\rm div}\\theta$. We justify the formula on appropriate examples.", "revisions": [ { "version": "v1", "updated": "2022-12-28T13:08:37.000Z" } ], "analyses": { "keywords": [ "intrinsic torsion", "scalar curvature", "dimensional riemannian manifold", "appropriate examples", "general riemannian" ], "note": { "typesetting": "TeX", "pages": 11, "language": "en", "license": "arXiv", "status": "editable" } } }