Mannheim-d'Ocagne-Koenderink type formulas for asymptotic directions.

Saved in:
Bibliographic Details
Title: Mannheim-d'Ocagne-Koenderink type formulas for asymptotic directions.
Authors: FUKUI, Toshizumi1, HONDA, Atsufumi2, UMEHARA, Masaaki3
Source: Proceedings of the Japan Academy, Series A: Mathematical Sciences. Jun2026, Vol. 102 Issue 6, p29-35. 7p.
Subjects: Gaussian curvature, Mathematical singularities, Surface geometry, Euclidean metric, Curvature, Mathematical formulas
Abstract: We consider a surface embedded in the Euclidean 3-space and fix a tangential vector v at a given point p on the surface. We first review the history of the formula obtained by Mannheim, d'Ocagne and Koenderink, which asserts that the Gaussian curvature of the surface at p can be obtained if one knows "the normal curvature at p with respect to v" and "the curvature at p of the contour line Γ of the surface" with respect to the orthogonal projection induced by v. However, this formula breaks down when v is an asymptotic direction. In such cases, we present analogues of the formula that involve an invariant associated with cusp singularities of Γ. [ABSTRACT FROM AUTHOR]
Copyright of Proceedings of the Japan Academy, Series A: Mathematical Sciences is the property of Japan Academy and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
Database: Engineering Source
Description
Abstract:We consider a surface embedded in the Euclidean 3-space and fix a tangential vector v at a given point p on the surface. We first review the history of the formula obtained by Mannheim, d'Ocagne and Koenderink, which asserts that the Gaussian curvature of the surface at p can be obtained if one knows "the normal curvature at p with respect to v" and "the curvature at p of the contour line Γ of the surface" with respect to the orthogonal projection induced by v. However, this formula breaks down when v is an asymptotic direction. In such cases, we present analogues of the formula that involve an invariant associated with cusp singularities of Γ. [ABSTRACT FROM AUTHOR]
ISSN:03862194
DOI:10.3792/pjaa.102.006