Revista Matemática Iberoamericana
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Published online: 2008-12-31
Projections of hypersurfaces in the hyperbolic space to hyperhorospheres and hyperplanesShyuichi Izumiya and Farid Tari (1) Hokkaido University, Sapporo, Japan
(2) Universidade de São Paulo, São Carlos, Brazil
We study in this paper orthogonal projections in a hyperbolic space to hyperhorospheres and hyperplanes. We deal in more details with the case of embedded surfaces $M$ in $H^3_+(-1)$. We study the generic singularities of the projections of $M$ to horospheres and planes. We give geometric characterizations of these singularities and prove duality results concerning the bifurcation sets of the families of projections. We also prove Koenderink type theorems that give the curvature of the surface in terms of the curvatures of the profile and the normal section of the surface.
Keywords: Bifurcation sets, contours, Legendrian duality, projections, profiles, hyperbolic space, singularities, de Sitter space, lightcone
Izumiya Shyuichi, Tari Farid: Projections of hypersurfaces in the hyperbolic space to hyperhorospheres and hyperplanes. Rev. Mat. Iberoam. 24 (2008), 895-920. doi: 10.4171/RMI/559