Meta Agent Programs

Abstract

There are numerous applications where one agent a needs to reason about the beliefs of another agent, as well as about the actions that other agents may take. Eiter et. al. introduced the concept of an agent program, and provided a language within which the operating principles of an agent could be declaratively encoded on top of imperative data structures. We first introduce certain belief data structures that an agent needs to maintain. Then we introduce the concept of a "Meta Agent Program" (MAP), that extends the Eiter et. al. framework, so as to allow agents to peform metareasoning. We build a formal semantics for MAPs, and show how this semantics supports not just beliefs agent a may have about agent b's state, but also beliefs about agents b's beliefs about agent c's actions, beliefs about b's beliefs about agent c's state, and so on. Finally, we provide a translation that takes any MAP as input and converts it into an agent program such that there is a one-one correspondence between the semantics of the MAP and the semantics of the resulting agent program. This correspondence allows an implementation of MAPs to be built on top of an implementation of agent programs. (Also cross-referenced as UMIACS-TR-98-43)