Modeling A Player’s Perspective I: Info-memory Protocols∗†

This two-part paper studies a player’s perspective on the social (game) situation he is in. In Part I we develop the theory of info-memory protocols from the viewpoint of the objective observer. This will be used for the development of the theory of inductive derivations of social views by an individual player in Part II. An infomemory protocol consists of an information protocol and a memory function for each player. An information protocol is an alternative formulation of an extensive game emphasizing information pieces and actions as primitives. We show that under the notion of an infomorphism, the class of information protocols satisfying certain axioms is equivalent to the class of extensive games in Kuhn’s sense. A memory function is a separate and explicit description of a player’s memory that allows us to capture and distinguish various aspects of bounded memory. We reconsider memory conditions on extensive games using a memory function.