English

Character Varieties of Generalized Torus Knot Groups

Geometric Topology 2025-09-15 v2 Algebraic Geometry Group Theory Representation Theory

Abstract

Given n=(n1,,nr)Nr\mathbf{n}=(n_{1},\ldots,n_{r})\in\mathbb{N}^r, let Γn\Gamma_{\mathbf{n}} be a group presentable as γ1,,γrγ1n1=γ2n2==γrnr.\left\langle \gamma_{1},\ldots,\gamma_{r}\:|\:\gamma_{1}^{n_{1}}=\gamma_{2}^{n_{2}}=\cdots=\gamma_{r}^{n_{r}}\right\rangle. If gcd(ni,nj)=1\gcd(n_i,n_j)=1 for all iji\not=j, we say Γn\Gamma_{\mathbf{n}} is a {\it generalized torus knot group} and otherwise say it is a {\it generalized torus link group}. This definition includes torus knot and link groups (r=2r=2), that is, fundamental groups of the complement of a torus knot or link in S3S^{3}. Let GG be a connected complex reductive affine algebraic group. We show that the GG-character varieties of generalized torus knot groups are path-connected. We then count the number of irreducible components of the SL(2,C)\mathrm{SL}(2,\mathbb{C})-character varieties of Γn\Gamma_{\mathbf{n}} when nin_i is odd for all ii.

Keywords

Cite

@article{arxiv.2401.15228,
  title  = {Character Varieties of Generalized Torus Knot Groups},
  author = {Carlos Florentino and Sean Lawton},
  journal= {arXiv preprint arXiv:2401.15228},
  year   = {2025}
}

Comments

21 pages, 2 figures, accepted for publication in the Mediterranean Journal of Mathematics

R2 v1 2026-06-28T14:28:43.179Z