fact: Definition isMarked' (s : sigSim) : bool := match s with | inr (sigList_X s) => isMarked s | _ => false end.
imports: Undecidability.TM.Basic.Mono Undecidability.TM.Combinators.Combinators Undecidability.TM.Code.Code Undecidability.TM.Single.EncodeTapes Undecidability.TM.Compound(TMTac MoveToSymbol Multi Shift)