MC-SOG: An LTL Model Checker Based on Symbolic Observation Graphs

Abstract

International audienceModel checking is a powerful and widespread technique for the verification of finite distributed systems. However, the main hindrance for wider application of this technique is the well-known state explosion problem. During the last two decades, numerous techniques have been proposed to cope with the state explosion problem in order to get a manageable state space. Among them, on-the-fly model-checking allows for generating only the ”interesting” part of the model while symbolic model-checking aims at checking the property on a compact representation of the system by using Binary Decision Diagram (BDD) techniques. In this paper, we propose a technique which combines these two approaches to check LTL∖X state-based properties over finite systems. During the model checking process, only an abstraction of the state space of the system, namely the symbolic observation graph, is (possibly partially) explored. The building of such an abstraction is guided by the property to be checked and is equivalent to the original state space graph of the system w.r.t. LTL∖X logic (i.e. the abstraction satisfies a given formula ϕ iff the system satisfies ϕ). Our technique was implemented for systems modeled by Petri nets and compared to an explicit model-checker as well as to a symbolic one (NuSMV) and the obtained results are very competitive

A Counterexample-Based Incremental and Modular Verification Approach

“…Such actions are said to be observed while the other actions of the system are unobserved. Previous results [9,17] show that such a formula is satisfied by the LTS if and only if it is satisfied by the respective SOG. The SOG is defined as a graph where each node is a set of states linked by unobserved actions and each arc is labelled by an observed action.…”

“…On the other hand, Symbolic Observation Graphs (SOGs) [9,17] provide an abstraction-based approach leading to a compact representation of the system's state space graph, and allowing for the analysis of properties expressed using LTL\X (Linear Time Logic [20] from which the "next operator" has been removed). We have shown a purely modular construction of these in [15].…”

“…In the first case, the abstraction satisfies the formula if and only if the original system does (e.g. [25,21,9,17,7]). In the second case, only a sufficient condition exists (i.e.…”

A Parallel Construction of the Symbolic Observation Graph: the Basis for Efficient Model Checking of Concurrent Systems

“…The SOG [22,24,15] is an abstraction of the reachability graph of concurrent systems. The construction of the SOG is guided by the set of actions occurring in the formula to be checked.…”

“…Such an obtained graph represents an abstraction of the system on which the verification of a LTL/X property is equivalent to the verification on the original reachability graph. It has been established (see e.g., [15,22,10] ) that the SOG-based approach can outperform purely symbolic techniques in model checking of LTL properties. In this work, we adopt a dynamic load balancing scheme in order to balance the load on threads sharing the SOG construction task.…”