Abstract. Modal µ-calculus is an expressive specification formalism for temporal properties of concurrent programs represented as Labeled Transition Systems (Ltss). However, its practical use is hampered by the complexity of the formulas, which makes the specification task difficult and error-prone. In this paper, we propose Mcl (Model Checking Language), an enhancement of modal µ-calculus with high-level operators aimed at improving expressiveness and conciseness of formulas. The main Mcl ingredients are parameterized fixed points, action patterns extracting data values from Lts actions, modalities on transition sequences described using extended regular expressions and programming language constructs, and an infinite looping operator specifying fairness. We also present a method for on-the-fly model checking of Mcl formulas on finite Ltss, based on the local resolution of boolean equation systems, which has a linear-time complexity for alternation-free and fairness formulas. Mcl is supported by the Evaluator 4.0 model checker developed within the Cadp verification toolbox.

Abstract. A Gals (Globally Asynchronous Locally Synchronous) system typically consists of a collection of sequential, deterministic components that execute concurrently and communicate using slow or unreliable channels. This paper proposes a general approach for modelling and verifying Gals systems using a combination of synchronous languages (for the sequential components) and process calculi (for communication channels and asynchronous concurrency). This approach is illustrated with an industrial case-study provided by Airbus: a Tftp/Udp communication protocol between a plane and the ground, which is modelled using the Eclipse/TopCased workbench for model-driven engineering and then analysed formally using the Cadp verification and performance evaluation toolbox.