fact: Fixpoint enc_stack (B : BSRS) := match B with | nil => ∅ | (s,t)::B => enc_stack B ∪ sing (opair (enc_string s) (enc_string t)) end.
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)