Descriptions of Game Actions

To describe simultaneous knowledge updates for di erent subgroups we propose an epistemic language with dynamic operators for actions. The language is interpreted on equivalence states (S5 states). The actions are interpreted as state transformers. Two crucial action constructors are learning and local choice. Learning is the dynamic equivalent of common knowledge. Local choice aids in constraining the interpretation of an action to a functional interpretation (state transformer). Bisimilarity is preserved under execution of actions. The language is applied to describe various actions in card games.