(** Direct transitive closure vs right-step extension *)

(* Specifications: *)
Lemma clos_tn1_trans : forall x y, clos_trans_n1 R x y -> clos_trans R x y.
Lemma clos_trans_tn1 :  forall x y, clos_trans R x y -> clos_trans_n1 R x y.
Lemma clos_trans_tn1_iff : forall x y,
clos_trans R x y <-> clos_trans_n1 R x y.