lodof.spad line 236 [edit on github]
AssociatedEquations provides functions to compute the associated equations needed for factoring operators
associatedEquations(op, m) returns [w, eq, lw, lop] such that eq(w) = 0 where w is the given minor, and lw_i = lop_i(w) for all the other minors.
associatedSystem(op, m) returns [M, w] such that the m-th associated equation system to L is w' = M w.
uncouplingMatrices(M) returns [A_1, ..., A_n] such that if y = [y_1, ..., y_n] is a solution of y' = M y, then [$y_j', y_j'', ..., y_j^(n)$] = $A_j y$ for all j's.