Partial information and uniform strategies

We present an alternating-time temporal epistemic logic with uniform strategies, interpreted in a novel way on transition systems for modelling situations in which agents with partial information interact to determine the way the system updates. This logic uATEL allows us to model what properties agents can enforce when they act according to strategies based on their knowledge. Apart from the usual memoryless strategies, we distinguish state-based memory, where agents recall the history of previous states, from perfect recall, where agents also recall their actions. We show that this makes a difference. Our logic includes three strategic operators for groups, representing the case where all the agents in the group cooperate actively, but do not share their knowledge, the case where some agents in the group may be passive, and the case where all the agents in the group share their knowledge. We include a detailed comparison to the literature on the subject.