proposition: Lemma clos_rstn1_trans : forall x y z, clos_refl_sym_trans_n1 R x y -> clos_refl_sym_trans_n1 R y z -> clos_refl_sym_trans_n1 R x z.
proof: Proof. intros x y z H1 H2. induction H2. - auto. - intros. right with y0; eauto. Defined.
imports: CRelationClasses Equations.Init Equations.Type.Logic Equations.Type.Relation