Crossings of signed permutations and q-Eulerian numbers of type B

Sylvie Corteel (1) , Matthieu Josuat-Vergès (2) , Jang Soo Kim (3)

1 LIAFA - Laboratoire d'informatique Algorithmique : Fondements et Applications
2 LIGM - Laboratoire d'Informatique Gaspard-Monge
3 UMN-MATH - School of Mathematics

In this paper we want to study combinatorics of the type B per- mutations and in particular the join statistics crossings, excedances and the number of negative entries. We generalize most of the results known for type A (i.e. zero negative entries) and use a mix of enumerative, algebraic and bijective techniques. This work has been motivated by permutation tableaux of type B introduced by Lam and Williams, and natural statistics that can be read on these tableaux. We mostly use (pignose) diagrams and labelled Motzkin paths for the combinatorial interpretations of our results.

Domaines: Combinatoire [math.CO]

Sylvie Corteel, Matthieu Josuat-Vergès, Jang Soo Kim. Crossings of signed permutations and q-Eulerian numbers of type B. Journal of Combinatorics, 2013, 4, pp.191-228. ⟨hal-00967541⟩