fact: Definition obembed n (s : obstring n) : obstring (S n) := match s with | Some (exist _ s H) => Some (exist _ s (le_S _ _ H)) | None => None end.
imports: Lia Arith Undecidability.PCP.PCP Undecidability.PCP.Util.PCP_facts Undecidability.Synthetic.DecidabilityFacts Undecidability(FOL.Utils.FullSyntax) Undecidability(FOL.FSAT) Undecidability.Shared.ListAutomation