An Institution of Hybrid Systems

Hybrid systems are systems that intermix discrete and continuous behavior. Interest in hybrid systems has grown in recent years, mainly because of their relation with embedded systems (systems that interact with the continuously changing real-world). In order to deal with complex problems, compositional specification and verification methods are needed. Using the specification language of HyTech as a starting point, an institution of hybrid systems is established. Generalizing the results for classical systems, free aggregation, interconnection and abstraction of hybrid systems are presented as categorial constructions within the proposed institution, at both the specification and the model levels. The HyTech parallel composition constructor is shown to be a particular case of interconnection. Compositional model checking of a complex system is shown to be possible by capitalizing on categorial structure. A class of properties that can be verified with HyTech is identified.