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arXiv 2312.04532math.CO
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Coxeter交换图

Coxeter interchange graphs

Brett Kolesnik, Rivka Mitchell, Tomasz Przybyłowski

AI总结:

本文引入Coxeter交换图,其顶点代表Coxeter竞赛图,边对应中性结构的操作;证明该图是正则的并几何描述其度数,还刻画了Coxeter竞赛图的得分序列集,推广Landau经典结果。

摘要:

Brualdi和Li引入了竞赛图交换图。在这种图中,每个顶点代表一个竞赛图,遍历一条边对应反转一个循环定向的三角形。这种三角形是中性的,因为其反转不影响得分序列。交换图编码了具有给定得分序列的竞赛图集的组合学,或者等价地,编码了离散几何中经典置换多面体的给定纤维的组合学。Coxeter竞赛图由第一作者和Sanchez引入,与Ardila、Castillo、Eur和Postnikov的Coxeter置换多面体相关。除了经典竞赛图中的常规竞争游戏外,Coxeter竞赛图还包含协作和单人游戏。我们引入了Coxeter交换图,这些图更为复杂,因为存在多个相互作用的中性结构。我们的主要结果表明Coxeter交换图是正则的,并根据Coxeter置换多面体中的距离描述了其度数。我们还刻画了Coxeter竞赛图的得分序列集,推广了Landau的经典结果。

英文摘要:

Brualdi and Li introduced tournament interchange graphs. In such a graph, each vertex represents a tournament. Traversing an edge corresponds to reversing a cyclically directed triangle. Such a triangle is neutral, in that its reversal does not affect the score sequence. An interchange graph encodes the combinatorics of the set of tournaments with a given score sequence, or equivalently, of a given fiber of the classical permutahedron from discrete geometry. Coxeter tournaments were introduced by the first author and Sanchez, in relation to the Coxeter permutahedra in Ardila, Castillo, Eur and Postnikov. Coxeter tournaments have collaborative and solitaire games, in addition to the usual competitive games in classical tournaments. We introduce Coxeter interchange graphs. These graphs are more intricate, as there are multiple neutral structures at play, which interact with one another. Our main result shows that the Coxeter interchange graphs are regular, and we describe the degree geometrically, in terms of distances in the Coxeter permutahedra. We also characterize the set of score sequences of Coxeter tournaments, generalizing a classical result of Landau.

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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