proposition: Lemma clos_rt_rt1n_iff : forall x y, clos_refl_trans R x y <-> clos_refl_trans_1n R x y.
proof: Proof. split. - apply clos_rt_rt1n. - apply clos_rt1n_rt. Defined.
imports: CRelationClasses Equations.Init Equations.Type.Logic Equations.Type.Relation