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Relative and affine normals. (English) Zbl 0643.53008

Motivated by a well-known representation of the affine normal vector of a hypersurface in equi-affine differential geometry, the author defines a ‘Laplace normal’ in relative differential geometry. It is obtained (up to a normalization) by applying the Laplace operator with respect to the first fundamental form of relative differential geometry to the position vector. The author shows that the Laplace normal can be interpreted as a relative normal with respect to a suitable gauge surface. The positions of relative and Laplace normals are discussed, especially for the cases of the Euclidean, equi-affine and centro-affine normalizations.
Reviewer: R.Schneider

MSC:

53A15 Affine differential geometry
Full Text: DOI

References:

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