They can be deferred, too. Case distinction: Decision either or. The case distinction is a branching in alternative processes depending on definition of the subsequent conditions. Uniting: The end of a parallel as the case may be alternative execution or also an integration of process chains is indicated by the uniting. Loop: A repatriation (loop, cycle) is represented by means of case distinction and uniting. The activities included in the loop are executed as long as the condition for the continuation is given. Modeling proceeding The modeling procedure for the illustration of business processes in IEM covers the following steps: System delimitation; Modeling; Model evaluation and use; and Model change. The system delimitation is the base of an efficient modeling. Starting out from a conceptual formulation the area of the real system to be shown is selected and interfaces will be defined to an environment. In addition, the detail depth of the model is also determined, i.e. the depth of the hierarchical decomposition relations in the view "business process model". The delimited real system is convicted with help of the IEM method in an abstract model. IEM is the construction of the two main positions "information model" and "business process model". The "information model" is made by the specification of the object classes to be modeled for "product", "order" and "resource" with the class structures as well as descriptive and relational features. By identification and description of functions, activities and its combination to processes the "business process model" is formed. As a general rule the construction of the "information model" follows first in which the modeling person can go back to available reference class structures. The reference classes which do not correspond to the real system or were not found to be relevant at the system delimitation are deleted. The missing relevant classes are inserted. After the object base is fixed, the activities and functions are joined together at the objects according to the "generic activity model" and with the help of combination elements to business processes. A model is made which can be analysed and changed if it is required. It often happens, that during the construction of the "business process model" new relevant object classes are identified so that the class trees getting completed. The construction of the two positions is, therefore, an iterative process. Afterward, weak points and improvement potentials can be identified in the course of