anchor.diff: -% @copyright 2011 Zuse Institute Berlin
  +% @copyright 2011,2012 Zuse Institute Berlin
   %
   %   Licensed under the Apache License, Version 2.0 (the "License");
   %   you may not use this file except in compliance with the License.
  
positive.code: %% @author Maik Lange <malange@informatik.hu-berlin.de>
  %% @doc    Approximate Reconciliation Tree (ART) implementation
  %%         Represents a packed merkle tree.
  %%         SRC: 2002 - J.Byers, J.Considine, M.Mitzenmachen
  %%              Fast Approximate Reconcilication of Set Differences
  %%              - BU Computer Science TR
  %% @end
  
negative.code: 
  -spec lookup(merkle_tree:mt_node(), art()) -> boolean().
  lookup(Node, Art) ->
      lookup_cf([{Node, get_correction_factor(Art)}], Art).
  
  -spec lookup_cf([{Node, CF}], Art) -> Result when
      is_subtype(Art,    art()),
      is_subtype(Node,   merkle_tree:mt_node()),
      is_subtype(CF,     non_neg_integer()),        %correction factor
      is_subtype(Result, boolean()).
  lookup_cf([], _Art) ->
      true;
  lookup_cf([{Node, 0} | L], {art, _Conf, _I, IBF, LBF} = Art) ->
  