Reasoning about the Interaction of Knowledge, Time and Concurrent Actions in the Situation Calculus

A formal framework for specifying and developing agents/robots must handle not only knowledge and sensing actions, but also time and concurrency. Researchers have extended the situation calculus to handle knowledge and sensing actions. Other researchers have addressed the issue of adding time and concurrent actions. Here both of these features are combined into a unified logical theory of knowledge, sensing, time, and concurrency. The result preserves the solution to the frame problem of previous work, maintains the distinction between indexical and objective knowledge of time, and is capable of representing the various ways in which concurrency interacts with time and knowledge. Furthermore, a method based on regression is developed for solving the projection problem for theories specified in this version of the situation calculus.