A Radical Reduction of UML's Core Semantics

UML’s current core semantics suffers both from excessive complexity and from being overly general. Resultant is a language definition that is difficult to master and to repair. This is the more disturbing as the current core and its extensions do very little to integrate statics and dynamics, even though the inseparability of these is a property of software from which many of the modelling difficulties arise. To better this unsatisfactory situation, we suggest a simple modelling core with few concepts that are easy to understand, yet cover most static and dynamic modelling aspects. We present our work, which is founded in elementary set theory, in natural language making it equally accessible for both practitioners and formalists.