More complex methods are defined as a combination of other methods. That is to say, a new method is to be specified (1) by a refinement of a constituent method that determines how the results of subtasks are to be combined, and (2) by specifying which methods are to be used in each subtask.
The following Tax-Discount method definition is an example of a method that has two subtasks specified with methods. The condition subtask checks whether the conjunction of two conditions--namely being married and having a yearly revenue smaller than $ 3000--holds. Notice that the items task of conjunction method also has double parenthesis since what is specified is not a set of boolean values (as conjunction requires) but a set of methods that will return boolean values. The result task has a method that determines the appropriate tax discount while otherwise task is a reference to zero discount.
It is important to notice that Noos is uniform in the sense that methods are also feature terms as any concept description. For this reason, methods can also have metalevels and, as we will see in § 2.4, this fact supports more complex method configurations.