Plp: A Generic Compiler for Ordered Logic Programs

Abstract

This paper describes a generic compiler, called plp, for translating ordered logic programs into standard logic programs under the answer set semantics. In an ordered logic program, preference information is expressed at the object level by atoms of the form s ≺ t, where s and t are names of rules. An ordered logic program is transformed into a second, regular, extended logic program wherein the preferences are respected, in that the answer sets obtained in the transformed theory correspond with the preferred answer sets of the original theory. Currently, plp treats three different types of preference strategies, viz. those proposed by (i) Brewka and Eiter, (ii) Delgrande, Schaub, and Tompits, and (iii) Wang, Zhou, and Lin. Since the result of the translation is an extended logic program, existing logic programming systems can be used as underlying reasoning engine. In particular, plp is conceived as a front-end to the logic programming systems dlv and smodels.