q-Rook Polynomials and Matrices over Finite Fields

Connections betweenq-rook polynomials and matrices over finite fields are exploited to derive a new statistic for Garsia and Remmel'sq-hit polynomial. Both this new statisticmatand another statistic for theq-hit polynomial ξ recently introduced by Dworkin are shown to induce different multiset Mahonian permutation statistics for any Ferrers board. In addition, for the triangular boards they are shown to generate different families of Euler–Mahonian statistics. For these boards the ξ family includes Denert's statisticden, and gives a new proof of Foata and Zeilberger's Theorem that (exc, den) is equidistributed with (des, maj). Thematfamily appears to be new. A proof is also given that theq-hit polynomials are symmetric and unimodal.