Reasoning about Finite-State Switched Systems

A

switched system

is composed of components. The components do not interact with one another. Rather, they all interact with the same environment, which switches one of them on at each moment in time. In standard concurrency, a component restricts the environment of the other components, thus the concurrent system has fewer behaviors than its components. On the other hand, in a switched system, a component suggests an alternative to the other components, thus the switched system has richer behaviors than its components.

We study finite-state switched systems, where each of the underlying components is a finite-state transducer. While the main challenge, namely compositionality, is similar in standard concurrent systems and in switched systems, the problems and solutions are different. In the verification front, we suggest and study an assume-guarantee paradigm for switched systems, and study formalisms in which satisfaction of a specification in all components imply its satisfaction in the switched system. In the synthesis front, we show that while compositional synthesis and design are undecidable, the problem of synthesizing a switching rule with which a given switched system satisfies an LTL specification is decidable.