Section: New Results

Efficient solvers and provers for CCSL

Participants : Frédéric Mallet, Xiaohong Chen.

One of the goal of the team is to promote the use of logical time in various application domains. This requires to have efficient solvers for CCSL. We have made considerable progresses on this part along two lines. One by relying on SMT solvers (like Z3), the other by building a dynamic logic amenable to building semi-automatic proofs for logical time properties of reactive systems. Then for some classes of problems we can efficient solving tools.

• The first step is to have an efficient Z3 library for solving CCSL specifications. We have improved a lot the performances over last year by getting rid of some of the existential quantifiers in our properties [35].

• Second, we use this solver to help requirement engineers elicite the requirements. We use execution traces to help generate valid satisfied CCSL specifications [28].

• Third, we have built a dynamic logics based on CCSL, where the formulae are derived from CCSL relational operators and programs include some of CCSL expressions and some imperative reactive constructs akin to Esterel programs. Then we have an interactive proof system, that helps prove that some reactive program satisfies a set of formulas at all time. As we use only a subset of CCSL then, we can restrict to a decidable subset of the logics and the SMT solver is always efficient. The SMT helps guide the semi-automatic proof [34] by identifying the next proof rules that can be used (or not).