English

A relation between the curvature ellipse and the curvature parabola

Differential Geometry 2017-08-17 v1

Abstract

At each point in an immersed surface in R4\mathbb R^4 there is a curvature ellipse in the normal plane which codifies all the local second order geometry of the surface. More recently, at the singular point of a corank 1 singular surface in R3\mathbb R^3, a curvature parabola in the normal plane which codifies all the local second order geometry has been defined. When projecting a regular surface in R4\mathbb R^4 to R3\mathbb R^3 in a tangent direction corank 1 singularities appear generically. The projection has a cross-cap singularity unless the direction of projection is asymptotic, where more degenerate singularities can appear. In this paper we relate the geometry of an immersed surface in R4\mathbb R^4 at a certain point to the geometry of the projection of the surface to R3\mathbb R^3 at the singular point. In particular we relate the curvature ellipse of the surface to the curvature parabola of its singular projection.

Keywords

Cite

@article{arxiv.1708.04651,
  title  = {A relation between the curvature ellipse and the curvature parabola},
  author = {Raúl Oset Sinha and Pedro Benedini Riul},
  journal= {arXiv preprint arXiv:1708.04651},
  year   = {2017}
}

Comments

14 pages, 1 figure