fact: Fixpoint combinations (B : BSRS) a b := match B with | nil => b ≡ ∅ | (s,t)::B => ∃ ∃ shift 2 b ≡ $0 ∪ $1 ∧ combinations B (shift 2 a) $1 ∧ is_rep (comb_rel s t) (shift 2 a) $0 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)