Enumerating Excedances With Linear Characters In Classical Weyl Groups
Séminaire lotharingien de combinatoire, Tome 74 (2015-2018)
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Several signed excedance-type statistics have nice formulae when summed over the symmetric group and over the hyperoctahedral group. Motivated by these, we consider sums of the form f\chi,n(q) = \sumw in W \chi(w) qexc(w) where W is a classical Weyl group of rank n, \chi is a non-trivial one-dimensional character of W, and exc(w) is the excedance statistic of w.
We give formulae for these sums in a more general multivariate setting. We sharpen existing results for types A and B and give new results for classical Weyl groups of type B and type D.