Conjugacy of Coxeter elements

TL;DR

This paper proves that in any Coxeter group, two Coxeter elements are conjugate if and only if their words are related by a sequence of rotations and legal commutations, generalizing previous special cases.

Contribution

It establishes a general equivalence between conjugacy and rotation equivalence for Coxeter elements across all Coxeter groups.

Findings

Coxeter elements are conjugate iff rotation equivalent in general Coxeter groups

Rotation and commutation sequences characterize conjugacy classes

Generalizes known results from special Coxeter groups

Abstract

For a Coxeter group (W,S), a permutation of the set S is called a Coxeter word and the group element represented by the product is called a Coxeter element. Moving the first letter to the end of the word is called a rotation and two Coxeter elements are rotation equivalent if their words can be transformed into each other through a sequence of rotations and legal commutations. We prove that Coxeter elements are conjugate if and only if they are rotation equivalent. This was known for some special cases but not for Coxeter groups in general.