English

Coloring invariants of knots and links are often intractable

Geometric Topology 2021-08-18 v1 Computational Complexity Group Theory

Abstract

Let GG be a nonabelian, simple group with a nontrivial conjugacy class CGC \subseteq G. Let KK be a diagram of an oriented knot in S3S^3, thought of as computational input. We show that for each such GG and CC, the problem of counting homomorphisms π1(S3K)G\pi_1(S^3\setminus K) \to G that send meridians of KK to CC is almost parsimoniously #P\mathsf{\#P}-complete. This work is a sequel to a previous result by the authors that counting homomorphisms from fundamental groups of integer homology 3-spheres to GG is almost parsimoniously #P\mathsf{\#P}-complete. Where we previously used mapping class groups actions on closed, unmarked surfaces, we now use braid group actions.

Keywords

Cite

@article{arxiv.1907.05981,
  title  = {Coloring invariants of knots and links are often intractable},
  author = {Greg Kuperberg and Eric Samperton},
  journal= {arXiv preprint arXiv:1907.05981},
  year   = {2021}
}

Comments

14 pages, 6 figures