Technical Report. Milano, Italy: University, Dept. Information Sciences, October 1990.
Abstract: The awareness that a mature specification language for distributed systems cannot avoid to support both process abstraction and data abstraction, gave rise to the definition of a class of high-level nets called OBJSA nets since they combine the specification language OBJ with Superposed Automata nets. The paper faces with a concrete design problem. In particular it introcues the notions of morphism and isomorphism for OBJSA Net Systems and shows that any OBJSA Net System can be reduced to a unique ``minimal model''. This allows the definition of equivalence classes of OBJSA models at the same level of abstraction. It gives both a net semantics for OBJSA Net Systems, and an algebraic semantics.
Keywords: OBJSA net, morphism(s), (minimal models); high-level net; OBJ, specification language; superposed automata net; net semantics; algebraic semantics.