European Journal of Combinatorics ( IF 1 ) Pub Date : 2020-12-02 , DOI: 10.1016/j.ejc.2020.103257 John Irving , Amarpreet Rattan
Parking functions of length are well known to be in correspondence with both labelled trees on vertices and factorizations of the full cycle into transpositions. In fact, these correspondences can be refined: Kreweras equated the area enumerator of parking functions with the inversion enumerator of labelled trees, while an elegant bijection of Stanley maps the area of parking functions to a natural statistic on factorizations of . We extend these relationships in two principal ways. First, we introduce a bivariate refinement of the inversion enumerator of trees and show that it matches a similarly refined enumerator for factorizations. Secondly, we characterize all full cycles such that Stanley’s function remains a bijection when the canonical cycle is replaced by . We also exhibit a connection between our refined inversion enumerator and Haglund’s bounce statistic on parking functions.
中文翻译:
树木,停车功能和全周期分解
停车长度 众所周知,它们与 整个周期的顶点和因式分解 进入 换位。实际上,可以对这些对应关系进行细化:Kreweras将停车功能的区域枚举数与带标签的树木的倒置枚举数等价,而Stanley的优雅双射则将停车功能的面积映射为自然分解的。我们以两种主要方式扩展这些关系。首先,我们对树的反演枚举器进行了双变量细化,并表明它与用于分解的相似细化的枚举器匹配。其次,我们表征所有完整周期 这样当规范循环时斯坦利函数仍然是双射 被替换为 。我们还展示了改进的倒数枚举器与Haglund的停车功能反弹统计之间的联系。