English

Genera of knots in the complex projective plane

Geometric Topology 2019-12-05 v1

Abstract

Our goal is to systematically compute the CP2\mathbb{C}P^2-genus of all prime knots up to 8-crossings. We obtain upper bounds on the CP2\mathbb{C}P^2-genus via coherent band surgery. We obtain lower bounds by obstructing homological degrees of potential slice discs. The obstructions are pulled from a variety of sources in low-dimensional topology and adapted to CP2\mathbb{C}P^2. There are 27 prime knots and distinct mirrors up to 7-crossings. We now know the CP2\mathbb{C}P^2-genus of all but 2 of these knots. There are 64 prime knots and distinct mirrors up to 8-crossings. We now know the CP2\mathbb{C}P^2-genus of all but 9 of these knots. Where the CP2\mathbb{C}P^2-genus was not determined explicitly, it was narrowed down to 2 possibilities. As a consequence of this work, we show an infinite family of knots such that the CP2\mathbb{C}P^2-genus of each knot differs from that of it's mirror.

Keywords

Cite

@article{arxiv.1912.01787,
  title  = {Genera of knots in the complex projective plane},
  author = {Jacob Pichelmeyer},
  journal= {arXiv preprint arXiv:1912.01787},
  year   = {2019}
}
R2 v1 2026-06-23T12:35:10.349Z