anchor.diff:  
   -define(Check_sum_fun(X), erlang:crc32(integer_to_list(X))). %hash function for checksum building
   
  --type key()     :: integer().
   -type value()   :: integer().
   -type cell()    :: {Count       :: non_neg_integer(),
  -                    KeySum      :: key(),
  +                    KeySum      :: integer(),
                       KeyHashSum  :: integer(),   %sum c(x) of all inserted keys x, for c = any hashfunction not in hfs
                       ValSum      :: value(),
                       ValHashSum  :: integer()}.  %sum c(y) of all inserted values y, for c = any hashfunction not in hfs
  
positive.code: operation_val(add) -> 1;
  operation_val(remove) -> -1.
  
  -spec change_table(iblt(), cell_operation(), key(), value()) -> iblt().
  change_table(#iblt{ hfs = Hfs, table = T, item_count = ItemCount, col_size = ColSize } = IBLT, 
               Operation, Key, Value) ->
      NT = lists:foldl(
             fun({ColNr, Col}, NewT) ->
                     NCol = change_cell(Col, 
                                        ?REP_HFS:apply_val(Hfs, ColNr, Key) rem ColSize,
                                        Key, Value, Operation),
                     [{ColNr, NCol} | NewT]
             end, [], T),
      IBLT#iblt{ table = NT, item_count = ItemCount + operation_val(Operation)}.   
  
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  
  -spec change_cell([cell()], pos_integer(), key(), value(), cell_operation()) -> [cell()].
  change_cell(Column, CellNr, Key, Value, Operation) ->        
      {HeadL, [Cell | TailL]} = lists:split(CellNr, Column),
      {Count, KeySum, KHSum, ValSum, VHSum} = Cell,
      lists:flatten([HeadL, 
  
negative.code: 
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  
  -spec get(iblt(), ?RT:key()) -> value() | not_found.
  get(#iblt{ table = T, hfs = Hfs, col_size = ColSize }, Key) ->
      p_get(T, Hfs, ColSize, Key).
  
  -spec p_get(table(), ?REP_HFS:hfs(), non_neg_integer(), ?RT:key()) -> value() | not_found.
  p_get([], _, _, _) -> not_found;
  p_get([{ColNr, Col} | T], Hfs, ColSize, Key) ->
      Cell = lists:nth((?REP_HFS:apply_val(Hfs, ColNr, Key) rem ColSize) + 1, Col),
  