2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/58783A new extension of the major index, defined in terms of Coxeter elements, is introduced. For the classical Weyl groups of type $B$, it is equidistributed with length. For more general wreath products it appears in an explicit formula for the Hilbert series of the (diagonal action) invariant algebra.23 pages, final form; to appear in the European Journal of CombinatoricsCombinatoricsRepresentation Theorytext