proposition: Theorem Rstar_transitive : forall (U : Type) (R : Relation U), Transitive (Rstar R).
proof: Proof. intros U R; red in |- *. intros x y z H'; elim H'; auto. intros x0 y0 z0 H'0 H'1 H'2 H'3; apply Rstar_n with y0; auto. Qed.
imports: Relations Confluence