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arXiv 0709.4241math.CO
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置换面体与广义结合面体

Permutahedra and generalized associahedra

Christophe Hohlweg, Carsten Lange, Hugh Thomas

摘要:

给定有限Coxeter系统$(W,S)$和Coxeter元$c$,构造了一个外法扇为N的简单多胞形.雷丁的寒武纪粉丝$F_c$,解决了雷丁的一个猜想,即这是可能的。我们称这个多面体为$c$ -广义结合面体。我们的方法推广Loday的实现的associahedron(一个类型$A$ $c$ -广义associahedron,其外部正常的风扇是不是集群风扇,但Coxeter风扇从Tamari格产生的粗化)到任何有限Coxeter组。$c$ -单点锥在构造中起着至关重要的作用,$c$ -寒武纪扇中的锥由来自考克斯特扇的单个最大锥组成。此外,如果$W$是一个外尔群和置换面体的顶点被选择在一个格与$W$,那么我们证明了我们的实现在这个格中有整数坐标。

英文摘要:

Given a finite Coxeter system $(W,S)$ and a Coxeter element $c$, we construct a simple polytope whose outer normal fan is N. Reading's Cambrian fan $F_c$, settling a conjecture of Reading that this is possible. We call this polytope the $c$-generalized associahedron. Our approach generalizes Loday's realization of the associahedron (a type $A$ $c$-generalized associahedron whose outer normal fan is not the cluster fan but a coarsening of the Coxeter fan arising from the Tamari lattice) to any finite Coxeter group. A crucial role in the construction is played by the $c$-singleton cones, the cones in the $c$-Cambrian fan which consist of a single maximal cone from the Coxeter fan. Moreover, if $W$ is a Weyl group and the vertices of the permutahedron are chosen in a lattice associated to $W$, then we show that our realizations have integer coordinates in this lattice.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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