anchor.diff:  ///     The edges of <paramref name="_arg1" />, as name-edge pairs.
   ///     This is wrapped in a Chessie result over <c>Error</c>.
   /// </returns>
  -let axiomatiseGraph : Graph -> (string * Axiom<SVGView, Command>) seq =
  +let axiomatiseGraph : Graph -> (string * Axiom<GView<Sym<Var>>, Command>) seq =
       mapEdges
           (fun { Name = n; SrcView = s ; DestView = t ; Command = c } ->
               (n, { Pre = match s with InnerView v -> v
  
positive.code:             /// <summary>
              ///     Set of nodes in the control-flow graph.
              /// </summary>
              Nodes: Map<NodeID, ViewExpr<SVGView> * NodeKind>
  
              /// <summary>
              ///     Set of edges in the control-flow graph.
  
negative.code: ///     <paramref name="graph" /> and its view is structurally equal
  ///     to <paramref name="nodeView" />.
  /// </returns>
  let nodeHasView (nodeName : NodeID) (nodeView : GView<Sym<Var>>) (graph : Graph)
    : bool =
      match (Map.tryFind nodeName graph.Contents) with
      | Some (InnerView v, _, _, _) -> v = nodeView
  