🤖 AI Summary
This work addresses the challenge that transition probabilities in real-world environments often exhibit epistemic uncertainty, rendering existing concurrent stochastic games— which require precise probabilities— ill-suited for practical application. To bridge this gap, we propose robust concurrent stochastic games and their subclass, interval concurrent stochastic games, which, for the first time, support modeling of probabilistic uncertainty. Our framework enables robust verification of both finite- and infinite-horizon objectives under worst-case assumptions, encompassing both zero-sum and non-zero-sum settings. We establish the theoretical foundations of this model, devise efficient verification algorithms, and extend robust analysis to social welfare–optimal Nash equilibria in non-zero-sum games. A prototype implementation in PRISM-games integrates interval probabilities, worst-case reasoning, and symbolic model checking. Experiments on multiple large-scale benchmarks demonstrate the scalability and effectiveness of our approach.
📝 Abstract
Autonomous systems often operate in multi-agent settings and need to make concurrent, strategic decisions, typically in uncertain environments. Verification and control problems for these systems can be tackled with concurrent stochastic games (CSGs), but this model requires transition probabilities to be precisely specified - an unrealistic requirement in many real-world settings. We introduce *robust CSGs* and their subclass *interval CSGs* (ICSGs), which capture epistemic uncertainty about transition probabilities in CSGs. We propose a novel framework for *robust* verification of these models under worst-case assumptions about transition uncertainty. Specifically, we develop the underlying theoretical foundations and efficient algorithms, for finite- and infinite-horizon objectives in both zero-sum and nonzero-sum settings, the latter based on (social-welfare optimal) Nash equilibria. We build an implementation in the PRISM-games model checker and demonstrate the feasibility of robust verification of ICSGs across a selection of large benchmarks.