English

Torus cannot collapse to a segment

Differential Geometry 2020-05-12 v2

Abstract

In earlier work, we analyzed the impossibility of codimension-one collapse for surfaces of negative Euler characteristic under the condition of a lower bound for the Gaussian curvature. Here we show that, under similar conditions, the torus cannot collapse to a segment. Unlike the torus, the Klein bottle can collapse to a segment; we show that in such a situation, the loops in a short basis for homology must stay a uniform distance apart.

Cite

@article{arxiv.2002.07523,
  title  = {Torus cannot collapse to a segment},
  author = {Mikhail G. Katz},
  journal= {arXiv preprint arXiv:2002.07523},
  year   = {2020}
}

Comments

8 pages, Journal of Geometry 111, Article number: 13 (2020)

R2 v1 2026-06-23T13:45:13.555Z