© 2001 by Oxford University Press
Original Article |
Minimizing Agent Specifications using a Logic of Knowledge and Actions
1 Department of Computer Science, William Paterson University of New Jersey, Wayne, NJ 07470, USA. E-mail: ndjatou{at}cs.wpunj.edu
Given the specification of an agent's behaviour in terms of what it can do at every task-domain situation, we propose a mechanism to derive an equivalent specification but with fewer states that is based on Milner's ‘observation equivalence’. This is done by identifying internal states of an agent that are ‘observation equivalent’. We also introduce the notion of ‘pertinent fact’ about an agent's behaviour at an internal state as a fact that is true at all internal states of the agent that are ‘observation equivalent’ to this particular state, and also define a new logic, Propositional Logic of Knowledge and Actions (PLKA), to specify and reason about the behaviour of an agent in terms of pertinent facts. A complete axiomatization of this logic, which stands as a conservative extension of both the logic S5 of knowledge and Propositional Dynamic Logic (PDL), and a characterization of an agent's behaviour in terms of ‘pertinent facts’ are also provided.
Keywords: Logic of knowledge; logic of knowledge and actions; object system; observation equivalence; procedural knowledge; propositional dynamic logic; rational behaviour; reactive systems
Received 8 August 1997.