Combinatorial study of the Dellac configurations and the q-extended normalized median Genocchi numbers

Ange Bigeni (1)

1 CTN - Combinatoire, théorie des nombres

In two recent papers (\textit{Mathematical Research Letters,18(6):1163--1178,2011} and \textit{European J. Combin.,33(8):1913--1918,2012}), Feigin proved that the Poincaré polynomials of the degenerate flag varieties have a combinatorial interpretation through the Dellac configurations, and related them to the $q$-extended normalized median Genocchi numbers $\bar{c}_n(q)$ introduced by Han and Zeng, mainly by geometric considerations. In this paper, we give combinatorial proofs of these results by constructing statistic-preserving bijections between the Dellac configurations and two other combinatorial models of $\bar{c}_n(q)$.

Mots clés: Dellac configurations; Dellac histories; Genocchi numbers; Dumont permutations

Domaines: Combinatoire [math.CO]

Ange Bigeni. Combinatorial study of the Dellac configurations and the q-extended normalized median Genocchi numbers. 2014. ⟨hal-00943622⟩