Transformation-based model checking temporal trust in multi-agent systems

Abstract

Several formal trust frameworks have been introduced in the area of Multi-Agent Systems (MASs). However, the problem of model checking trust logics is still a challenging research topic. In this paper, we address this challenge by proposing a formal and fully automatic model checking technique for two temporal logics of trust. We start by reviewing TCTL, a Computation Tree Logic of Trust, which has been recently proposed. We also introduce TCTLC for conditional trust. Then, we introduce sound and complete transformation-based algorithms that automatically transform the problem of model checking TCTL and TCTLC into the problem of model checking CTL. Moreover, we prove that although TCTL and TCTLC extend CTL, their model checking algorithms still have the same time complexity for explicit models, which is P-complete with regard to the size of the model and length of the formula, and the same space complexity for concurrent programs, which is PSPACE-complete with regard to the size of the components of these programs. Finally, experiments conducted on a standard industrial case study of auto-insurance claim processing demonstrate the efficiency and scalability of our approach in verifying TCTL and TCTLC formulae.