English

Surfaces and their Profile Curves

Geometric Topology 2025-11-14 v2

Abstract

This paper examines the relationship between the knotting of an embedded surface in R3\R^3 and the knotting of its fold curves, formed by the singular set of projection to a plane. The first result shows that every surface, no matter how knotted, can be isotoped so that its fold curves form an unlink. A second result defines a new invariant which gives a complete obstruction to turning a fixed curve on a surface into a fold curve.

Keywords

Cite

@article{arxiv.2205.01737,
  title  = {Surfaces and their Profile Curves},
  author = {Joel Hass},
  journal= {arXiv preprint arXiv:2205.01737},
  year   = {2025}
}

Comments

12 pages, 11 figures

R2 v1 2026-06-24T11:06:21.045Z