proposition: Lemma atom_subst_id {ff:falsity_flag} phi : phi[ atom /atom] = phi.
proof: Proof. induction phi. - easy. - cbn. easy. - cbn. rewrite IHphi1. now rewrite IHphi2. - cbn. now rewrite IHphi. Qed.
imports: Undecidability.Synthetic(Definitions DecidabilityFacts EnumerabilityFacts ListEnumerabilityFacts ReducibilityFacts) Undecidability(Shared.ListAutomation Shared.Dec) Coq(Eqdep_dec) Coq.Vectors.Vector Undecidability.Shared.Libs.PSL.Vectors(Vectors) EqdepFacts