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Related papers: Chains in the noncrossing partition lattice

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We consider $m$-divisible non-crossing partitions of $\{1,2,\ldots,mn\}$ with the property that for some $t\leq n$ no block contains more than one of the first $t$ integers. We give a closed formula for the number of multi-chains of such…

Combinatorics · Mathematics 2023-02-07 Christian Krattenthaler , Henri Mühle

We present results on the enumeration of crossings and nestings for matchings and set partitions. Using a bijection between partitions and vacillating tableaux, we show that if we fix the sets of minimal block elements and maximal block…

Combinatorics · Mathematics 2007-05-23 William Y. C. Chen , Eva Y. P. Deng , Rosena R. X. Du , Richard P. Stanley , Catherine H. Yan

We give a combinatorial model for the bounded derived category of graded modules over the dual numbers in terms of arcs on the integer line with a point at infinity. Using this model we describe the lattice of thick subcategories of the…

Representation Theory · Mathematics 2016-11-08 Sira Gratz , Greg Stevenson

The notion of noncrossing partitions of a partially ordered set (poset) is introduced here. When the poset in question is $[n]=\{1,2,\dots, n\}$ with the complete order of natural numbers, conventional noncrossing partitions arise. The…

Combinatorics · Mathematics 2024-09-09 Ricky X. F. Chen

Introduced by Reading, the shard intersection order of a finite Coxeter group $W$ is a lattice structure on the elements of $W$ that contains the poset of noncrossing partitions $NC(W)$ as a sublattice. Building on work of Bancroft in the…

Combinatorics · Mathematics 2013-06-18 T. Kyle Petersen

Given a finite irreducible Coxeter group $W$, a positive integer $d$, and types $T_1,T_2,...,T_d$ (in the sense of the classification of finite Coxeter groups), we compute the number of decompositions $c=\si_1\si_2 cdots\si_d$ of a Coxeter…

Combinatorics · Mathematics 2010-01-18 Christian Krattenthaler , Thomas Müller

We define noncrossing partitions of a marked surface without punctures (interior marked points). We show that the natural partial order on noncrossing partitions is a graded lattice and describe its rank function topologically. Lower…

Combinatorics · Mathematics 2026-05-22 Nathan Reading

Let W be a finite crystallographic reflection group. The generalized Catalan number of W coincides both with the number of clusters in the cluster algebra associated to W, and with the number of noncrossing partitions for W. Natural…

Representation Theory · Mathematics 2011-06-15 Aslak Bakke Buan , Idun Reiten , Hugh Thomas

In this paper, we use a simple discrete dynamical model to study integer partitions and their lattice. The set of reachable configurations of the model, with the order induced by the transition rule defined on it, is the lattice of all…

Combinatorics · Mathematics 2021-03-08 Matthieu Latapy , Thi Ha Duong Phan

For a fixed integer $k$, we consider the set of noncrossing partitions, where both the block sizes and the difference between adjacent elements in a block is $1\bmod k$. We show that these $k$-indivisible noncrossing partitions can be…

Combinatorics · Mathematics 2021-07-26 Henri Mühle , Philippe Nadeau , Nathan Williams

We present an algorithm for approximating linear categories of partitions (of sets). We report on concrete computer experiments based on this algorithm which we used to obtain first examples of so-called non-easy linear categories of…

Category Theory · Mathematics 2024-02-07 Daniel Gromada , Moritz Weber

In 2007, D.I. Panyushev defined a remarkable map on the set of nonnesting partitions (antichains in the root poset of a finite Weyl group). In this paper we identify Panyushev's map with the Kreweras complement on the set of noncrossing…

Combinatorics · Mathematics 2011-03-10 Drew Armstrong , Christian Stump , Hugh Thomas

Let $\mathcal{L}$ be the noncrossing partition lattice associated to a finite Coxeter group $W$. In this paper we construct explicit bases for the top homology groups of intervals and rank-selected subposets of $\mathcal{L}$. We define a…

Combinatorics · Mathematics 2023-01-26 Yang Zhang

We solve two open problems in Coxeter-Catalan combinatorics. First, we introduce a family of rational noncrossing objects for any finite Coxeter group, using the combinatorics of distinguished subwords. Second, we give a type-uniform proof…

Combinatorics · Mathematics 2022-08-02 Pavel Galashin , Thomas Lam , Minh-Tâm Quang Trinh , Nathan Williams

Higher-order notions of Kreweras complementation have appeared in the literature in the works of Krawczyk, Speicher, Mastnak, Nica, Arizmendi, Vargas, and others. While the theory has been developed primarily for specific applications in…

Combinatorics · Mathematics 2025-08-26 Kurusch Ebrahimi-Fard , Loïc Foissy , Joachim Kock , Frédéric Patras

Reflection groups, geometry of the discriminant and noncrossing partitions. When W is a well-generated complex reflection group, the noncrossing partition lattice NCP_W of type W is a very rich combinatorial object, extending the notion of…

Group Theory · Mathematics 2010-10-22 Vivien Ripoll

Schutzenberger's theorem for the ordinary RSK correspondence naturally extends to Chen et. al's correspondence for matchings and partitions. Thus the counting of bilaterally symmetric $k$-noncrossing partitions naturally arises as an…

Combinatorics · Mathematics 2008-10-09 Guoce Xin , Terence Y. J. Zhang

We introduce the category of finite strings and study its basic properties. The category is closely related to the augmented simplex category, and it models categories of linear representations. Each lattice of non-crossing partitions…

Representation Theory · Mathematics 2021-09-14 Henning Krause

Noncrossing partition posets in a Coxeter group $W$ can fail to be lattices when $W$ is not finite. When the lattice property fails for $W$ of affine type, McCammond and Sulway's construction provides a larger lattice that contains the…

Representation Theory · Mathematics 2025-10-21 Eric J. Hanson , Nathan Reading

We prove an instance of the cyclic sieving phenomenon, occurring in the context of noncrossing parititions for well-generated complex reflection groups.

Combinatorics · Mathematics 2009-03-30 David Bessis , Victor Reiner