A concept is introduced in this article which has strong practical impact for computer aided system configuration. System configuration is a cumbersome and fault sensitive task while setting up systems in a broad range of business applications like ERP （enterprise resource planning） and other workflow-systems. Given a generic process or workflow model in YAWL-notation （yet another workflow language） or any other process modeling language like business process model and notation or WFMC （workflow management coalition）, it could be stated that, by using a set of reduction rules as introduced, it is possible to generate a hierarchically structured tree of sub graphs of the workflow graph-representation. According to the notation used, authors call these sub graphs facts. The tree structure of the graph-representation on one hand and the logical relation between the branches and leafs of the tree on the other can be utilized to create a set of constraints and dependencies among the single facts. Some researchers showed that the nested branches can be associated to （predefined） questions with respect to the configuration of a workflow management system, for instance an ERP-application. They presented an algorithm which dynamically sorts the questions and answers in a maximum efficient configuration path, while working through the corresponding questionnaire. By combining the different elements as facts, constraints on questions, and configuration space, it is thus possible to algorithmically generate the efficient structured and interactive questionnaire for the configuration of workflow systems and algorithmically check the consistency （dead lock free, free of synchronization structural conflict） of the underlying workflow model. The concept was tested in the prototype of the interactive questionnaire for configuration of the web-service based ERP-Application Posity.
