proposition: Lemma M_prep_enc s s' : M_prep_string s (M_enc_string s') = M_enc_string (s ++ s').
proof: Proof. Proof using M_ZF VIEQ. induction s; cbn; trivial. now rewrite IHs. Qed.
imports: Undecidability.FOL.ZF Undecidability.FOL.Syntax.Facts Undecidability.FOL.Semantics.Tarski.FullFacts Undecidability.FOL.Sets.ZF Lia Undecidability.PCP(PCP Util.PCP_facts Reductions.PCPb_iff_dPCPb) Undecidability(Shared.ListAutomation)