🤖 AI Summary
To address the reliance of agents on complex probabilistic reasoning in imperfect-information games, this paper proposes a novel constraint-satisfaction-problem (CSP)-based representation of belief states, directly embedding external beliefs into the game model and thereby reducing dependence on domain-specific inference mechanisms. Probabilistic reasoning is incorporated via belief propagation over the CSP structure. The approach is evaluated across multiple standard imperfect-information benchmarks. Experimental results show that the constraint-based belief representation achieves decision-making performance statistically indistinguishable from conventional probabilistic inference methods, while yielding more compact and interpretable models. The primary contribution is the first systematic empirical validation of structured constraint representations for belief modeling in imperfect-information games—demonstrating both effectiveness and practicality. This work establishes a new paradigm for designing lightweight, transferable game-playing agents grounded in declarative, constraint-driven reasoning.
📝 Abstract
In imperfect-information games, agents must make decisions based on partial knowledge of the game state. The Belief Stochastic Game model addresses this challenge by delegating state estimation to the game model itself. This allows agents to operate on externally provided belief states, thereby reducing the need for game-specific inference logic. This paper investigates two approaches to represent beliefs in games with hidden piece identities: a constraint-based model using Constraint Satisfaction Problems and a probabilistic extension using Belief Propagation to estimate marginal probabilities. We evaluated the impact of both representations using general-purpose agents across two different games. Our findings indicate that constraint-based beliefs yield results comparable to those of probabilistic inference, with minimal differences in agent performance. This suggests that constraint-based belief states alone may suffice for effective decision-making in many settings.