On a state-based constraint-oriented notation for specifying reactive systems

The constraint oriented descriptive paradigm is a powerful conceptual tool for representing knowledge in the broad sense. The notion of state is conveniently assumed as an explicit one in the behavioural description of many real cere world reactive systems, especially for those with asynchronous interaction capabilities. This work aims at putting together the two features above into a unique notation, called CO-notation, aimed at the specification of reactive systems. The CO--notation has both a graphical and a textual syntax. In this paper, the CO-notation is given an operational semantics; some laws equality and an expansion theorem are proved, which allow for carrying out semantic-preservin transformations of specifications.