proposition: Lemma enc_derivations_step B n : FSTeq ⊢ opair (tnumeral n) (enc_stack (derivations B n)) ∈ enc_derivations B n.
proof: Proof. destruct n; cbn. - apply FST_sing_el. - apply FST_adj; auto. apply DI1. apply FST_refl'. auto. Qed.
imports: Undecidability.FOL.Syntax.Facts Undecidability.FOL.Semantics.Tarski.FullFacts Undecidability.FOL.Deduction.FullNDFacts Undecidability.FOL.Sets.FST Undecidability.FOL.FST Undecidability.FOL.Reductions.PCPb_to_FST Undecidability.PCP(PCP Util.PCP_facts Reductions.PCPb_iff_dPCPb) Undecidability(Shared.ListAutomation)