fact: Definition vander_last n (a : 'rV[R]_n.+1) := \matrix_(i < n.+1, j < n.+1) if i == 0 then 1 else if j == 0 then 0 else (a``_j) ^+ i - a``_0 * (a``_j) ^+ i.-1.
imports: mathcomp(all_ssreflect ssralg perm zmodp) mathcomp(matrix) ssralg_ext