Generalized cluster complexes and Coxeter combinatorics

Fuente: arXiv
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Auteurs principaux: Fomin, Sergey, Reading, Nathan
Format: Preprint
Publié: 2005
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author Fomin, Sergey
Reading, Nathan
author_facet Fomin, Sergey
Reading, Nathan
contents We introduce and study a family of simplicial complexes associated to an arbitrary finite root system and a nonnegative integer parameter m. For m=1, our construction specializes to the (simplicial) generalized associahedra or, equivalently, to the cluster complexes for the cluster algebras of finite type. Our computation of the face numbers and h-vectors of these complexes produces the enumerative invariants defined in other contexts by C.A.Athanasiadis, suggesting links to a host of well studied problems in algebraic combinatorics of finite Coxeter groups, root systems, and hyperplane arrangements. Recurrences satisfied by the face numbers of our complexes lead to combinatorial algorithms for determining Coxeter-theoretic invariants. That is, starting with a Coxeter diagram of a finite Coxeter group, one can compute the Coxeter number, the exponents, and other classical invariants by a recursive procedure that only uses most basic graph-theoretic concepts applied to the input diagram. In types A and B, we rediscover the constructions and results obtained by E.Tzanaki <math.CO/0501100>.
format Preprint
id arxiv_https___arxiv_org_abs_math_0505085
institution arXiv
publishDate 2005
record_format arxiv
spellingShingle Generalized cluster complexes and Coxeter combinatorics
Fomin, Sergey
Reading, Nathan
Combinatorics
Representation Theory
20F55
We introduce and study a family of simplicial complexes associated to an arbitrary finite root system and a nonnegative integer parameter m. For m=1, our construction specializes to the (simplicial) generalized associahedra or, equivalently, to the cluster complexes for the cluster algebras of finite type. Our computation of the face numbers and h-vectors of these complexes produces the enumerative invariants defined in other contexts by C.A.Athanasiadis, suggesting links to a host of well studied problems in algebraic combinatorics of finite Coxeter groups, root systems, and hyperplane arrangements. Recurrences satisfied by the face numbers of our complexes lead to combinatorial algorithms for determining Coxeter-theoretic invariants. That is, starting with a Coxeter diagram of a finite Coxeter group, one can compute the Coxeter number, the exponents, and other classical invariants by a recursive procedure that only uses most basic graph-theoretic concepts applied to the input diagram. In types A and B, we rediscover the constructions and results obtained by E.Tzanaki <math.CO/0501100>.
title Generalized cluster complexes and Coxeter combinatorics
topic Combinatorics
Representation Theory
20F55
url https://arxiv.org/abs/math/0505085