proposition: Lemma wf_projection : forall pb w lpb proof, In (W pb w) (build_well_formed_matching_problem_list lpb proof) -> In pb lpb.
proof: Proof. intros pb w lpb; induction lpb. contradiction. intros proof In_wpb; simpl in In_wpb; elim In_wpb; clear In_wpb; intro In_wpb. injection In_wpb; intro; left; trivial. right; apply (IHlpb _ In_wpb). Qed.
imports: Coq(Arith List Wellfounded Wf_nat) CoLoR(more_list list_permut list_sort term_spec term_o equational_theory ac matching dickson matching_well_formed matching_well_founded matching_sound matching_complete dickson)