2. The apparatus of claim 1 wherein at least one task of the set of N classification tasks is a multi-class task.
2. The apparatus of claim 1 wherein at least one task of the set of N classification tasks is a multi-class task. 3. The apparatus of claim 2 wherein the learning of decision rules for nodes further includes (i) determining whether a final decision can be made at a node for a task of the set of N classification tasks that is completed at the node and (ii) adding a decision node for any completed task.