VAL@SU-AI.ARPA.UUCP (05/19/86)
AUTOEPISTEMIC LOGIC, STRATIFIED PROGRAMS AND CIRCUMSCRIPTION Michael Gelfond and Halina Przymusinska University of Texas at El Paso Thursday, May 22, 4pm MJH 252 In Moore's autoepistemic logic, a set of beliefs of a rational agent is described by a "stable expansion" of his set of premises T. If this expansion is unique then it can be viewed as the set of theorems which follow from T in autoepistemic logic. Marek gave a simple syntactic condition on T which guarantees the existence of a unique stable expansion. We will propose another sufficient condition, which is suggested by the definition of "stratified" programs in logic programming. The declarative semantics of such programs can be defined using fixed points of non-monotonic operators (Apt, Blair and Walker; Van Gelder) or by means of circumscription (Lifschitz). We show how this semantics can be interpreted in terms of autoepistemic logic.