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Let W be a Coxeter group. In this paper, we establish that, up to going to some finite index normal subgroup W_0 of W, any two cyclically reduced expressions of conjugate elements of W_0 only differ by a sequence of braid relations and…

Group Theory · Mathematics 2014-04-01 Timothée Marquis

In this article, we establish some new combinatorial properties of cone types in Coxeter groups. Firstly, we show that for any element $x$ in a Coxeter group $W$ and root $\beta$ in its inversion set $\Phi(x)$, the set of elements $y \in W$…

Group Theory · Mathematics 2026-05-06 Yeeka Yau

We continue the study of the maximally clustered elements for simply laced Coxeter groups which were recently introduced by Losonczy. Such elements include as a special case the freely braided elements of Losonczy and the author, which in…

Combinatorics · Mathematics 2007-05-23 R. M. Green

For well-generated complex reflection groups, Chapuy and Stump gave a simple product for a generating function counting reflection factorizations of a Coxeter element by their length. This is refined here to record the number of reflections…

Combinatorics · Mathematics 2017-08-22 Elise delMas , Thomas Hameister , Victor Reiner

We give a geometric proof that minimal length elements in a (twisted) conjugacy class of a finite Coxeter group $W$ have remarkable properties with respect to conjugation, taking powers in the associated Braid group and taking centralizer…

Representation Theory · Mathematics 2019-12-19 Xuhua He , Sian Nie

We describe an approach, via Malle's permutation $\Psi$ on the set of irreducible characters $\text{Irr}(W)$, that gives a uniform derivation of the Chapuy-Stump formula for the enumeration of reflection factorizations of the Coxeter…

Combinatorics · Mathematics 2018-11-19 Theo Douvropoulos

We enlarge a Coxeter group into a category, with one object for each finite parabolic subgroup, encoding the combinatorics of double cosets. This category, the singular Coxeter monoid, is connected to the geometry of partial flag varieties.…

Representation Theory · Mathematics 2021-08-16 Ben Elias , Hankyung Ko

In the combinatorics of finite finite Coxeter groups, there is a simple formula giving the number of maximal chains of noncrossing partitions. It is a reinterpretation of a result by Deligne which is due to Chapoton, and the goal of this…

Combinatorics · Mathematics 2018-01-09 Matthieu Josuat-Vergès

The excess of an element $w$ of a finite Coxeter group $W$ is the minimal value of $l(x) + l(y) - l(w)$, where $x$, $y$ are elements of $W$ such that $x^2 = y^2 = 1$ and $w = xy$. Every element of a finite Coxeter group is either an…

Group Theory · Mathematics 2015-08-28 Sarah B. Hart , Peter J. Rowley

In [APS], the authors characterize the partitions of $n$ whose corresponding representations of $S_n$ have nontrivial determinant. The present paper extends this work to all irreducible finite Coxeter groups $W$. Namely, given a nontrivial…

Representation Theory · Mathematics 2017-10-10 Debarun Ghosh , Steven Spallone

We discuss metric and combinatorial properties of Thompson's group T, including normal forms for elements and unique tree pair diagram representatives. We relate these properties to those of Thompson's group F when possible, and highlight…

Group Theory · Mathematics 2018-03-19 Jose Burillo , Sean Cleary , Melanie Stein , Jennifer Taback

Let $W$ denote a simply-laced Coxeter group with $n$ generators. We construct an $n$-dimensional representation $\phi$ of $W$ over the finite field $F_2$ of two elements. The action of $\phi(W)$ on $F_2^n$ by left multiplication is…

Representation Theory · Mathematics 2010-08-03 Hau-wen Huang , Chih-wen Weng

We review Stanley's seminal work on the number of reduced words of the longest element of the symmetric group and his Stanley symmetric functions. We shed new light on this by giving a crystal theoretic interpretation in terms of decreasing…

Combinatorics · Mathematics 2017-03-01 Anne Schilling

We introduce stable reflection length in Coxeter groups, as a way to study the asymptotic behaviour of reflection length. This creates connections to other well-studied stable length functions in groups, namely stable commutator length and…

Group Theory · Mathematics 2025-04-02 Francesco Fournier-Facio , Marco Lotz , Timothée Marquis

In well-known work, Kazhdan and Lusztig (1979) defined a new set of Hecke algebra basis elements (actually two such sets) associated to elements in any Coxeter group. Often these basis elements are computed by a standard recursive algorithm…

Representation Theory · Mathematics 2015-05-15 Leonard Scott , Timothy Sprowl

Given an irreducible well-generated complex reflection group W with Coxeter number h, we call a Coxeter element any regular element (in the sense of Springer) of order h in W; this is a slight extension of the most common notion of Coxeter…

Combinatorics · Mathematics 2014-12-16 Victor Reiner , Vivien Ripoll , Christian Stump

Let $(W,S)$ be a Coxeter system and $\Gamma$ be a group of automorphisms of $W$ such that $\gamma(S)=S$ for all $\gamma \in \Gamma$. Then it is known that the group of fixed points $W^\Gamma$ is again a Coxeter group with a canonically…

Representation Theory · Mathematics 2014-12-18 Meinolf Geck , Lacrimioara Iancu

The reduced expressions for a given element $w$ of a Coxeter group $(W, S)$ can be regarded as the vertices of a directed graph $\mathcal{R}(w)$; its arcs correspond to the braid moves. Specifically, an arc goes from a reduced expression…

Combinatorics · Mathematics 2026-04-14 Darij Grinberg , Alexander Postnikov

Let $F_2$ be the free group on two generators and let $H$ be a subgroup of $F_2$. We investigate a method for calculating the number of elements in a coset of $H$ that have a given length when written in reduced form. More specifically,…

Group Theory · Mathematics 2025-11-19 Michael Reilly , Cory Shields

The usual combinatorial model for the 0-Hecke algebra of the symmetric group is to consider the algebra (or monoid) generated by the bubble sort operators. This construction generalizes to any finite Coxeter group W. The authors previously…

Combinatorics · Mathematics 2011-02-07 Florent Hivert , Anne Schilling , Nicolas M. Thiéry