proposition: Theorem wf_RL : well_founded RL.
proof: Proof. apply (wf_inverse_image _ _ Co PtoS); auto. try exact wf_Co. Qed.
imports: Coq(Arith Inclusion Inverse_Image Wf_nat Relation_Definitions) Coq(Relation_Operators Lexicographic_Product) Buchberger(Relation_Operators_compat LetP)