Formal semantics of executable node and activity group of UML 2.5 activity diagram

The semantics of Unified Modeling Language (UML) version 2.5, as defined by Object Management Group (OMG), are informal which leads to critical problems like ambiguities, inconsistencies, vagueness and misinterpretations. The solution to all aforementioned issues associated with UML is the transformation of UML informal semantics into formal mathematical semantics. The Executable Node and Activity Group are principal components of UML 2.5 Activity Diagram and they have not been completely formalized in existing researches so far. Our earlier publications presented formalization of structural semantics of UML 2.5 Activity Diagram in Z notation. This paper is an extension of our previous work by comprehensive formalization of structural semantics of Executable Node and Activity Group into Z notation. The defined formal semantic are then verified using various proof techniques offered by Z/EVES toolset.