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Given a finite group with a generating subset there is a well-established notion of length for a group element given in terms of its minimal length expression as a product of elements from the generating set. Recently, certain quantities…

We consider the set of affine permutations that avoid a fixed permutation pattern. Crites has given a simple characterization for when this set is infinite. We find the generating series for this set using the Coxeter length statistic and…

Combinatorics · Mathematics 2015-01-14 Brant Jones

In this paper, we introduce a novel approach for generating random elements of a finite group given a set of generators of that. Our method draws upon combinatorial group theory and automata theory to achieve this objective. Furthermore, we…

Formal Languages and Automata Theory · Computer Science 2023-11-29 MohammadJavad Vaez , Marjan Kaedi , Mahdi Kalbasi

In this paper, we study the structure of braid graphs in simply-laced Coxeter systems. We prove that every reduced expression has a unique factorization as a product of so-called links, which in turn induces a decomposition of the braid…

Combinatorics · Mathematics 2024-09-09 Fadi Awik , Jadyn Breland , Quentin Cadman , Dana C. Ernst

For a finite real reflection group $W$ with Coxeter element $\gamma$ we give a uniform proof that the closed interval, $[I, \gamma]$ forms a lattice in the partial order on $W$ induced by reflection length. The proof involves the…

Combinatorics · Mathematics 2007-05-23 Thomas Brady , Colum Watt

Previous work has shown that the disarray (or displacement) of an (affine) (signed) permutation is bounded in terms of its Coxeter length. Here, we characterize the permutations for which the bound is sharp in two ways: in terms of a…

Combinatorics · Mathematics 2024-04-10 Joel Brewster Lewis , Bridget Eileen Tenner

We give examples of finitely presented groups containing elements with irrational (in fact, transcendental) stable commutator length, thus answering in the negative a question of M. Gromov. Our examples come from 1-dimensional dynamics, and…

Geometric Topology · Mathematics 2007-10-02 Dongping Zhuang

In symmetric groups, studies of permutation factorizations or triples of permutations satisfying certain conditions have a long history. One particular interesting case is when two of the involved permutations are long cycles, for which…

Combinatorics · Mathematics 2022-08-04 Ricky X. F. Chen

We consider a procedure to reduce simply generated trees by iteratively removing all leaves. In the context of this reduction, we study the number of vertices that are deleted after applying this procedure a fixed number of times by using…

Combinatorics · Mathematics 2019-11-11 Benjamin Hackl , Clemens Heuberger , Stephan Wagner

We study the minimal length elements in some double cosets of Coxeter groups and use them to study Lusztig's $G$-stable pieces and the generalization of $G$-stable pieces introduced by Lu and Yakimov. We also use them to study the minimal…

Representation Theory · Mathematics 2007-05-23 Xuhua He

The expected number of Yang-Baxter moves appearing in a reduced decomposition of the longest element of the Coxeter group of type B_n is computed to be 2-4/n. For the same element, the expected number of 0101 or 1010 factors appearing in a…

Combinatorics · Mathematics 2007-05-23 Bridget Eileen Tenner

A monoid $M$ generated by a set $S$ of symbols can be described as the set of equivalence classes of finite words in $S$ under some relations that specify when some contiguous sequence of symbols can be replaced by another. If $a,b\in S$, a…

Combinatorics · Mathematics 2011-01-26 Matthew J. Samuel

In the 1950s, H. S. M. Coxeter considered the quotients of braid groups given by adding the relation that all half Dehn twist generators have some fixed, finite order. He found a remarkable formula for the order of these groups in terms of…

Geometric Topology · Mathematics 2025-09-23 Ethan Dlugie , Tahsin Saffat

A cofactor representation of an ideal element, that is, a representation in terms of the generators, can be considered as a certificate for ideal membership. Such a representation is typically not unique, and some can be a lot more…

Symbolic Computation · Computer Science 2024-04-10 Clemens Hofstadler , Thibaut Verron

We prove universal (case-free) formulas for the weighted enumeration of factorizations of Coxeter elements into products of reflections valid in any well-generated reflection group $W$, in terms of the spectrum of an associated operator,…

Combinatorics · Mathematics 2023-06-14 Guillaume Chapuy , Theo Douvropoulos

For a Coxeter element $c$ of a finite Coxeter group, we consider a family of subword complexes parameterized by reduced expressions of the longest element. This family generalizes $c-$cluster complexes. We describe vertices of these…

Combinatorics · Mathematics 2020-11-18 Mikhail Gorsky

Petersen and Tenner defined the depth statistic for Coxeter group elements which, in the symmetric group, can be described in terms of a cost function on transpositions. We generalize that cost function to the other classical (finite and…

Combinatorics · Mathematics 2024-02-07 Joel Brewster Lewis , Bridget Eileen Tenner

We prove two extensions of Hansson and Hultman's word property for certain analogues of reduced words associated to twisted involutions in Coxeter groups. Our first extension concerns the superset of such words in which terms with a natural…

Combinatorics · Mathematics 2023-01-05 Eric Marberg

We consider some questions about formal languages that arise when inverses of letters, words and languages are defined. The reduced representation of a language over the free monoid is its unique equivalent representation in the free group.…

Formal Languages and Automata Theory · Computer Science 2009-10-26 Thomas Ang , Giovanni Pighizzini , Narad Rampersad , Jeffrey Shallit

For $n$ at least 7 and $n$ equal to 5, we give generating sets of size 2 for the commutator subgroup of the braid group on $n$ strands. These generating sets are of the smallest possible cardinality. For $n$ equal to 4 or 6, we give…

Geometric Topology · Mathematics 2020-03-11 Kevin Kordek
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