English

On the tree-width of knot diagrams

Geometric Topology 2019-05-24 v2

Abstract

We show that a small tree-decomposition of a knot diagram induces a small sphere-decomposition of the corresponding knot. This, in turn, implies that the knot admits a small essential planar meridional surface or a small bridge sphere. We use this to give the first examples of knots where any diagram has high tree-width. This answers a question of Burton and of Makowsky and Mari\~no.

Keywords

Cite

@article{arxiv.1809.02172,
  title  = {On the tree-width of knot diagrams},
  author = {Arnaud de Mesmay and Jessica Purcell and Saul Schleimer and Eric Sedgwick},
  journal= {arXiv preprint arXiv:1809.02172},
  year   = {2019}
}

Comments

14 pages, 6 figures. V2: Minor updates to exposition