fact: Fixpoint encode_string (s : list (Fin.t n)) := match s with | [] => [] | i :: l => false :: encode_sym i ++ true :: encode_string l end.
imports: Undecidability.TM.Compound.TMTac Undecidability.TM.Basic.Mono Undecidability.TM.Compound.Multi Undecidability.TM.Combinators.Combinators