English

Permutations with few inversions

Combinatorics 2023-05-17 v1

Abstract

A curious generating function S0(x)S_0(x) for permutations of [n][n] with exactly nn inversions is presented. Moreover, (xC(x))iS0(x)(xC(x))^iS_0(x) is shown to be the generating function for permutations of [n][n] with exactly nin-i inversions, where C(x)C(x) is the generating function for the Catalan numbers.

Cite

@article{arxiv.2305.09457,
  title  = {Permutations with few inversions},
  author = {Anders Claesson and Atli Fannar Franklín and Einar Steingrímsson},
  journal= {arXiv preprint arXiv:2305.09457},
  year   = {2023}
}
R2 v1 2026-06-28T10:35:54.288Z