  In this paper we show by using the example of UML, how a software engineering
method can benefit from an integrative mathematical foundation. The
mathematical foundation is given by a mathematical system model. This model
provides the basis both for integrating the various description techniques of
UML and for implementing methodical support. After describing the basic
concepts of the system model, we give a short overview of the UML description
techniques. Then we show how they fit into the system model framework and
sketch an approach to structure the UML development process such that it
provides methodological guidance for developers.
