English

Mahonian and Euler-Mahonian statistics for set partitions

Combinatorics 2022-11-29 v2

Abstract

A partition of the set [n]:={1,2,,n}[n]:=\{1,2,\ldots,n\} is a collection of disjoint nonempty subsets (or blocks) of [n][n], whose union is [n][n]. In this paper we consider the following rarely used representation for set partitions: given a partition of [n][n] with blocks B1,B2,,BmB_{1},B_{2},\ldots,B_{m} satisfying maxB1<maxB2<<maxBm\max B_{1}<\max B_{2}<\cdots<\max B_{m}, we represent it by a word w=w1w2wnw=w_{1}w_{2}\ldots w_{n} such that iBwii\in B_{w_{i}}, 1in1\leq i\leq n. We prove that the Mahonian statistics INV, MAJ, MAJd_{d}, rr-MAJ, Z, DEN, MAK, MAD are all equidistributed on set partitions via this representation, and that the Euler-Mahonian statistics (des, MAJ), (mstc, INV), (exc, DEN), (des, MAK) are all equidistributed on set partitions via this representation.

Keywords

Cite

@article{arxiv.2202.02089,
  title  = {Mahonian and Euler-Mahonian statistics for set partitions},
  author = {Shao-Hua Liu},
  journal= {arXiv preprint arXiv:2202.02089},
  year   = {2022}
}
R2 v1 2026-06-24T09:19:43.754Z