anchor.diff:              )
           #endif
           // Discard the intermediate variables
  -        |> fun (F, _, _) -> F+        |> fun (F, _, _) -> F
  
positive.code:     and 'U : comparison> =
      Map<'T, Set<'U>>
  
  //
  [<RequireQualifiedAccess; CompilationRepresentation(CompilationRepresentationFlags.ModuleSuffix)>]
  module internal PartialFunction =
      //
      let empty : PartialFunction<'T, 'U> = Map.empty
  
      //
      let add source target (func : PartialFunction<'T,' U>) : PartialFunction<'T,' U> =
          let targets =
              match Map.tryFind source func with
  
negative.code: 
  *)
  
  namespace Graham.Graph
  
  open System.Diagnostics
  