proposition: Theorem in_incl : forall (A : Type) (p q : list A) (a b : A), incl p q -> In a p -> In a q.
proof: Proof. auto. Qed.
imports: Coq(Arith Inclusion Inverse_Image Wf_nat Relation_Definitions) Coq(Relation_Operators Lexicographic_Product) Buchberger(Relation_Operators_compat LetP)