anchor.diff:      end.
   
   % @private
  -is_covered_helper(#interval2{first=First, last=Last}, _) when First >= Last ->
  -    true;
   is_covered_helper(Interval, Intervals) ->
       %io:format("helper: ~p ~p~n", [Interval, Intervals]),
       %io:format("find_start: ~p~n", [find_start(Interval#interval2.first, Intervals, [])]),
  
positive.code: 	true -> 
  	    (Begin =< Id) or (Id =< End)
      end.
  
negative.code: 	none ->
  	    false;
  	{CoversStart, RemainingIntervals} ->
  	    case greater_equals_than(CoversStart#interval2.last, Interval#interval2.last) of
  		true ->
  		    true;
  		false ->
  		    is_covered_helper(intervals:new(CoversStart#interval2.last, Interval#interval2.last), RemainingIntervals)
  	    end
      end.
  