Can Intuition Become Rigorous? Foundations for UML Model Verification Tools1

The Unified Modeling Language, UML, is the objectoriented notation adopted as the standard for objectoriented Analysis and Design by the Object Management Group. This paper reports on research to facilitate the formal revision of UML informal specifications. The approach is based on the algebraic specification formal theory, which is used to formalize the UML Statechart Diagrams and subsequently verify them. To illustrate the proposal, the so-called orthogonality property is investigated. This property is modeled at the UML metamodel level so that its fulfillment on the part of any particular UML Statechart diagram can be mathematically proven or disproven. The formal models obtained are specified in the executable formal language Maude thus providing the additional advantage of using them as functional prototypes. These results lead up to a whole formalization of the UML, which can be used in practice, and lay the foundations for the construction of rigorous UML CASE tools.