apply wf_incl.
exact wf_Fl.
Qed.
Definition PtoS :
list (poly A0 eqA ltM) * list (poly A0 eqA ltM) -> sigS FPset.
intros H'; case H'.
intros P1 P2.
exact (existS FPset P1 P2).
Defined.
Definition RL (x y : list (poly A0 eqA ltM) * list (poly A0 eqA ltM)) :
Prop := Co (PtoS x) (PtoS y).

Theorem wf_RL : well_founded RL.
apply (wf_inverse_image _ _ Co PtoS); auto.