Some remarks on the joint distribution of descents and inverse descents
The electronic journal of combinatorics, Tome 20 (2013) no. 1
We study the joint distribution of descents and inverse descents over the set of permutations of $n$ letters. Gessel conjectured that the two-variable generating function of this distribution can be expanded in a given basis with nonnegative integer coefficients. We investigate the action of the Eulerian operators that give the recurrence for these generating functions. As a result we devise a recurrence for the coefficients in question but are unable to settle the conjecture. We examine generalizations of the conjecture and obtain a type $B$ analog of the recurrence satisfied by the two-variable generating function. We also exhibit some connections to cyclic descents and cyclic inverse descents. Finally, we propose a combinatorial model for the joint distribution of descents and inverse descents in terms of statistics on inversion sequences.
DOI :
10.37236/2135
Classification :
05A05, 05A15
Mots-clés : permutations, descents, inverse descents, Eulerian polynomials
Mots-clés : permutations, descents, inverse descents, Eulerian polynomials
Affiliations des auteurs :
Mirkó Visontai  1
@article{10_37236_2135,
author = {Mirk\'o Visontai},
title = {Some remarks on the joint distribution of descents and inverse descents},
journal = {The electronic journal of combinatorics},
year = {2013},
volume = {20},
number = {1},
doi = {10.37236/2135},
zbl = {1267.05015},
url = {http://geodesic.mathdoc.fr/articles/10.37236/2135/}
}
Mirkó Visontai. Some remarks on the joint distribution of descents and inverse descents. The electronic journal of combinatorics, Tome 20 (2013) no. 1. doi: 10.37236/2135
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