Open Logic Theory Composition in a Software Engineering Perspective

In a modern approach to software design, development and maintenance, new models of application building are required, which replace the traditional phase-refinement, waterfall model with the notion of software evolution [1]. In fact, software systems are in practice always built incrementally, and requirement analysis continues, de facto, also during the development process (requirement adjustment), interleaved with design updating and implementation. So, the availability of prototypes, intended as concrete and executable models of (selected aspects of) a system, on which to make tests and evaluations, plays a fundamental role. Moreover, in order to assure that requirements correctly specify the desired system behaviour, formal methods for requirement specification, analysis and evaluation seem to be needed, together with effective forms for requirement storing, maintenance and reuse [2,3]. However, requirement specification and validation remains useless, from the practical viewpoint, if no way is provided to transfer such analysis results in the system organization and code. This is why a reduction of the traditional gap between specification and coding is even more needed. Yet, software engineering demand good support for both in-the-small and inthe-large system design, as well as for open, evolutionary software systems, which can modify and adapt themselves both depending on the world state and as a reaction to internal or external events.