Cycles on a multiset with only even-odd drops
Abstract
For a finite subset $A$ of $\mathbb{Z}_{>0}$, Lazar and Wachs (2019) conjectured that the number of cycles on $A$ with only even-odd drops is equal to the number of D-cycles on $A$. In this note, we introduce cycles on a multiset with only even-odd drops and prove bijectively a multiset version of their conjecture. As a consequence, the number of cycles on $[2n]$ with only even-odd drops equals the Genocchi number $g_n$. With Laguerre histories as an intermediate structure, we also construct a bijection between a class of permutations of length $2n-1$ known to be counted by $g_n$ invented by Dumont and the cycles on $[2n]$ with only even-odd drops.
- Publication:
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arXiv e-prints
- Pub Date:
- August 2021
- DOI:
- arXiv:
- arXiv:2108.03790
- Bibcode:
- 2021arXiv210803790L
- Keywords:
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- Mathematics - Combinatorics
- E-Print:
- 7 pages, 2 figures