anchor.diff:  inverse('/=') -> '=='.
   
   prop_binop() ->
  -    ?FORALL({A,B,OP}, {any(),any(),elements(['>','<'])},
  +    ?FORALL({A,B,OP}, {any(),any(),elements(['>','<','==','=:=','=/=','/='])},
   	    erlang:OP(A,B) 
   	    ==
   	    begin 
  
positive.code: 		 ==
  		 lists:reverse(Ys) ++ lists:reverse(Xs))).
  					 
  prop_delete() ->
    fails(
      ?FORALL(L,list(int()), 
  	?IMPLIES(L /= [],
  	    ?FORALL(I,elements(L), 
  
negative.code: 	    X < Y).
  
  
  tuple_failure_test() ->
      false = check(?FORALL(T, {int()},
  			  begin
  			      {V} = T,
  			      V > 0
  			  end)).
  