English

Commuting graphs on Coxeter groups, Dynkin diagrams and finite subgroups of $SL(2,\mathbb{C})$

Group Theory 2017-12-11 v2 Algebraic Geometry

Abstract

For a group HH and a non empty subset ΓH\Gamma\subseteq H, the commuting graph G=C(H,Γ)G=\mathcal{C}(H,\Gamma) is the graph with Γ\Gamma as the node set and where any x,yΓx,y \in \Gamma are joined by an edge if xx and yy commute in HH. We prove that any simple graph can be obtained as a commuting graph of a Coxeter group, solving the realizability problem in this setup. In particular we can recover every Dynkin diagram of ADE type as a commuting graph. Thanks to the relation between the ADE classification and finite subgroups of \SL(2,\C)\SL(2,\C), we are able to rephrase results from the {\em McKay correspondence} in terms of generators of the corresponding Coxeter groups. We finish the paper studying commuting graphs C(H,Γ)\mathcal{C}(H,\Gamma) for every finite subgroup H\SL(2,\C)H\subset\SL(2,\C) for different subsets ΓH\Gamma\subseteq H, and investigating metric properties of them when Γ=H\Gamma=H.

Keywords

Cite

@article{arxiv.1703.02480,
  title  = {Commuting graphs on Coxeter groups, Dynkin diagrams and finite subgroups of $SL(2,\mathbb{C})$},
  author = {Umar Hayat and Álvaro Nolla de Celis and Fawad Ali},
  journal= {arXiv preprint arXiv:1703.02480},
  year   = {2017}
}

Comments

Re-estructured and large parts rewritten