English

On the curvature bounded sphere problem in $\mathbb{R}^3$

Differential Geometry 2026-01-27 v2

Abstract

We prove that if a topological sphere smoothly embedded into R3\mathbb{R}^3 with normal curvatures absolutely bounded by 11 is contained in an open ball of radius 22, then the region it bounds must contain a unit ball. This result suggests a potential direction for a problem formulated by D.Burago and A.Petrunin asking whether a topological sphere smoothly embedded in R3\mathbb{R}^3 with normal curvatures absolutely bounded by 11 encloses a volume of at least 43π\frac{4}{3}\pi. The appendix presents an example illustrating an alternative aspect for this problem.

Keywords

Cite

@article{arxiv.2507.06245,
  title  = {On the curvature bounded sphere problem in $\mathbb{R}^3$},
  author = {Hongda Qiu},
  journal= {arXiv preprint arXiv:2507.06245},
  year   = {2026}
}
R2 v1 2026-07-01T03:52:08.107Z