proposition: Lemma succ_inj x y : iσ x = iσ y -> x = y.
proof: Proof. Proof using M_correct. intros H%eq_sem. now apply eq_sem, (succ_inj' x y). Qed.
imports: PeanoNat Lia Vector Undecidability.SOL(SOL PA2) Undecidability.Shared.Libs.PSL(Vectors) Undecidability.SOL.Util(Syntax Subst Tarski) Undecidability.Synthetic(Definitions DecidabilityFacts EnumerabilityFacts ListEnumerabilityFacts ReducibilityFacts) Undecidability.Shared.Dec