English

More bijections for Entringer and Arnold families

Combinatorics 2022-03-22 v3

Abstract

The Euler number EnE_n (resp. Entringer number En,kE_{n,k}) enumerates the alternating (down-up) permutations of {1,,n}\{1,\dots,n\} (resp. starting with kk). The Springer number SnS_n (resp. Arnold number Sn,kS_{n,k}) enumerates the type BB alternating permutations (resp. starting with kk). In this paper, using bijections we first derive the counterparts in {\em Andr\'e permutations} and {\em Simsun permutations} for the Entringer numbers (En,k)(E_{n,k}), and then the counterparts in {\em signed Andr\'e permutations} and {\em type BB increasing 1-2 trees} for the Arnold numbers (Sn,k)(S_{n,k}).

Keywords

Cite

@article{arxiv.2006.00507,
  title  = {More bijections for Entringer and Arnold families},
  author = {Heesung Shin and Jiang Zeng},
  journal= {arXiv preprint arXiv:2006.00507},
  year   = {2022}
}

Comments

21 pages, 3 figures, 6 tables