fact: Definition ccons n b (s : obstring n) : obstring n := match s with | Some (exist _ s _) => match (le_dec (|b::s|) n) with | left H => obcast H | right _ => None end | 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