  A result of Foata and Schutzenberger states that two statistics on
permutations, the number of inversions and the inverse major index, have the
same distribution on a descent class. We give a multivariate generalization of
this property: the sorted vectors of the Lehmer code, of the inverse majcode,
and of a new code (the inverse saillance code), have the same distribution on a
descent class, and their common multivariate generating function is a flagged
ribbon Schur function.
