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Related papers: A note on the scatteredness of reflection orders

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The characterization of orbits of roots under the action of a Coxeter element is a fundamental tool in the study of finite root systems and their reflection groups. This paper develops the analogous tool in the affine setting, adding detail…

Combinatorics · Mathematics 2026-05-13 Nathan Reading , Salvatore Stella

Let $W$ be a Coxeter group and $r\in W$ a reflection. If the group of order 2 generated by $r$ is the intersection of all the maximal finite subgroups of $W$ that contain it, then any isomorphism from $W$ to a Coxeter group $W'$ must take…

Group Theory · Mathematics 2007-05-23 W. N. Franzsen , R. B. Howlett , B. Mühlherr

The finite orbits of the braid group action on Stokes matrices are studied and are shown to be the orbits on ordered sets of reflections, generating finite groups. All invariants of a reflection arrangement are determined. Determination of…

Mathematical Physics · Physics 2007-05-23 Alexandre Stefanov

For Coxeter groups with sufficiently large braid relations, we prove that the sequence of powers of a Coxeter element has unbounded reflection length. We establish a connection between the reflection length functions on arbitrary Coxeter…

Group Theory · Mathematics 2024-06-11 Marco Lotz

We prove that the weak order on an infinite Coxeter group contains infinite antichains if and only if the group is not affine.

Combinatorics · Mathematics 2007-05-23 Axel Hultman

Two partial orders on a reflection group, the codimension order and the prefix order, are together called the absolute order when they agree. We show that in this case the absolute order on a complex reflection group has the strong Sperner…

Combinatorics · Mathematics 2020-11-03 Christian Gaetz , Yibo Gao

We enumerate factorizations of a Coxeter element in a well generated complex reflection group into arbitrary factors, keeping track of the fixed space dimension of each factor. In the infinite families of generalized permutations, our…

Combinatorics · Mathematics 2024-02-07 Joel Brewster Lewis , Alejandro H. Morales

For an infinite Coxeter system, one can extend the weak right order to the set of infinite reduced words. This is called limit weak order. In [Transformation Groups 18(1), 2013, 179-231], Lam and Pylyavskyy showed that for affine Weyl…

Group Theory · Mathematics 2021-01-12 Weijia Wang

Aiming for a revival of the theory of crystallographic complex reflection groups, we compute (minimal) Coxeter-like reflection presentations for the infinite families of those non-genuine groups which satisfy Steinberg's fixed point…

Group Theory · Mathematics 2025-10-10 Davide Dal Martello

Let $(W,S)$ be a Coxeter system and suppose that $w \in W$ is fully commutative (in the sense of Stembridge) and has a reduced expression beginning (respectively, ending) with $s \in S$. If there exists $t\in S$ such that $s$ and $t$ do not…

Combinatorics · Mathematics 2018-01-04 Dana C. Ernst

Let W be a finite group generated by unitary reflections and A be the set of reflecting hyperplanes. We will give a characterization of the logarithmic differential forms with poles along A in terms of anti-invariant differential forms. If…

Representation Theory · Mathematics 2007-05-23 Hiroaki Terao , Anne V. Shepler

We discuss the classification of reflection subgroups of finite and affine Weyl groups from the point of view of their root systems. A short case free proof is given of the well known classification of the isomorphism classes of reflection…

Group Theory · Mathematics 2009-09-03 M. J. Dyer , G. I. Lehrer

Let W be a finite complex reflection group acting on the complex vector space V and let A(W) = (A(W), V) be the associated reflection arrangement. In an earlier paper by the last two authros, we classified all inductively free reflection…

Group Theory · Mathematics 2014-07-22 Nils Amend , Torsten Hoge , Gerhard Roehrle

We propose generalizations of Calogero models that exhibit invariance with respect to the infinite Weyl groups of affine, hyperbolic, and Lorentzian types. Our approach involves deriving closed analytic formulas for the action of the…

Mathematical Physics · Physics 2024-01-26 Francisco Correa , Andreas Fring , Octavio Quintana

We prove the $K(\pi,1)$ conjecture for affine Artin groups: the complexified complement of an affine reflection arrangement is a classifying space. This is a long-standing problem, due to Arnol'd, Pham, and Thom. Our proof is based on…

Group Theory · Mathematics 2020-12-08 Giovanni Paolini , Mario Salvetti

A Coxeter group admits infinite-dimensional irreducible complex representations if and only if it is not finite or affine. In this paper, we provide a construction of some of those representations for certain Coxeter groups using some…

Representation Theory · Mathematics 2025-03-25 Hongsheng Hu

Based on the third author's thesis in this article we complete the local recognition of commuting reflection graphs of spherical Coxeter groups arising from irreducible crystallographic root systems.

Group Theory · Mathematics 2015-03-27 Ralf Köhl , Jonathan I. Hall , Armin Straub

Let $W$ be a finite Coxeter group. We classify the reflection subgroups of $W$ up to conjugacy and give necessary and sufficient conditions for the map that assigns to a reflection subgroup $R$ of $W$ the conjugacy class of its Coxeter…

Group Theory · Mathematics 2012-01-26 J. Matthew Douglass , Goetz Pfeiffer , Gerhard Roehrle

Let $(W,S)$ be an arbitrary Coxeter system. For each word $\omega$ in the generators we define a partial order--called the {\sf $\omega$-sorting order}--on the set of group elements $W_\omega\subseteq W$ that occur as subwords of $\omega$.…

Combinatorics · Mathematics 2009-03-30 Drew Armstrong

The principal objects studied in this note are Coxeter groups $W$ that are neither finite nor affine. A well known result of de la Harpe asserts that such groups have exponential growth. We consider quotients of $W$ by its parabolic…

Group Theory · Mathematics 2007-05-23 Sankaran Viswanath