An Epistemic Strategy Logic

Abstract

This paper presents an extension of temporal epistemic logic with operators that quantify over agent strategies. Unlike previous work on alternating temporal epistemic logic, the semantics works with systems whose states explicitly encode the strategy being used by each of the agents. This provides a natural way to express what agents would know were they to be aware of some of the strategies being used by other agents. A number of examples that rely upon the ability to express an agent's knowledge about the strategies being used by other agents are presented to motivate the framework, including reasoning about game theoretic equilibria, knowledge-based programs, and information theoretic computer security policies. Relationships to several variants of alternating temporal epistemic logic are discussed. The computational complexity of model checking the logic and several of its fragments are also characterized.