fact: Definition Vanmx : 'M[ {mpoly R[n]} ]_n := \matrix_(i, j < n) 'X_i ^+ (n - 1 - j).
imports: HB(structures) mathcomp(all_ssreflect) mathcomp(ssralg ssrint fingroup perm zmodp binomial) mathcomp(ssrcomplements freeg mpoly) tools permcomp presentSn sorted partition mathcomp(matrix)