English

Spacious knots

Geometric Topology 2018-06-25 v3

Abstract

We show that there exist hyperbolic knots in the 3-sphere such that the set of points of large injectivity radius in the complement take up the bulk of the volume. More precisely, given a finite volume hyperbolic manifold, for any bound R>0 on injectivity radius, consider the set of points with injectivity radius at least R; we call this the R-thick part of the manifold. We show that for any ϵ>0\epsilon>0, there exists a knot K in the 3-sphere so that the ratio of the volume of the R-thick part of the knot complement to the volume of the knot complement is at least 1ϵ1-\epsilon. As R approaches infinity, and as ϵ\epsilon approaches zero, this gives a sequence of knots that is said to Benjamini--Schramm converge to hyperbolic space. This answers a question of Brock and Dunfield.

Keywords

Cite

@article{arxiv.1610.07731,
  title  = {Spacious knots},
  author = {Autumn E. Kent and Jessica S. Purcell},
  journal= {arXiv preprint arXiv:1610.07731},
  year   = {2018}
}

Comments

V3: 10 pages, 1 figure. Minor changes. To appear in Mathematical Research Letters. V2: 10 pages, 1 figure. Details added to proof of lemma 4.1, as well as minor revisions elsewhere. V1: 8 pages, 1 figure