Approximating general logic programs
Chitta R. Baral, Michael Gelfond, Olga M. Kosheleva · 1993
Consider an informal specification S 1 containing the closed world assumption (CWA) for its domain of discourse, the specification S 2 obtained from S 1 by removing CWA, a general logic program \\Pi formalizing S 1 , and an extended logic program T formalizing S 2 . We will say that T is an approximation of \\Pi. The goal of this paper is to investigate the relationship between formalizations \\Pi and T . In particular we give a mathematical definition of approximation, demonstrate its applicability by several examples, present an algorithm which constructs approximation of a large class of general logic programs. 1 Introduction As was demonstrated in recent years, traditional logic programming language provides a powerful tool for knowledge representation. Its main nonmonotonic features - closed world assumption [Rei78] and negation as failure [Cla78] - make it possible to express many interesting types of common-sense knowledge which are not readily expressible in classical logic....