proposition: Lemma F_injective x y: F x = F y -> x = y.
proof: Proof. intros H; unfold F in H; eapply injective_I__S in H. now injection H. Qed.
imports: RelationClasses Morphisms List Lia Init.Nat Setoid Undecidability.HOU(calculus.calculus second_order.diophantine_equations systemunification nth_order_unification)