anchor.diff:      true;
   is_between(_, plus_infinity, plus_infinity) ->
       true;
  +is_between(minus_infinity, _, plus_infinity) ->
  +    true;
  +is_between(X, minus_infinity, plus_infinity) ->
  +    false;
   is_between(X, Y, plus_infinity) ->
       X =< Y;
   is_between(minus_infinity, minus_infinity, _) ->
  
positive.code: 	none ->
  	    false;
  	{CoversStart, RemainingIntervals} ->
  	    if
  		CoversStart#interval2.last >= Interval#interval2.last ->
  		    true;
  		true ->
  		    is_covered_helper(intervals:new(CoversStart#interval2.last, Interval#interval2.last), RemainingIntervals)
  	    end
      end.
  
negative.code: 	true -> 
  	    (Begin =< Id) or (Id =< End)
      end.
  
  greater_equals_than(minus_infinity, minus_infinity) ->
      true;
  greater_equals_than(minus_infinity, X) ->
      false;
  greater_equals_than(plus_infinity, plus_infinity) ->
      true;
  greater_equals_than(X, plus_infinity) ->
      false;
  greater_equals_than(X, Y) ->
      X >= Y.
  