Implementing prioritized reasoning in logic programming

Prioritized reasoning is an important extension of logic programming and is a powerful tool for expressing desiderata on the program solutions in order to establish the best ones. This paper discusses the implementation of the case of preference relation among atoms and introduces a system, called CHOPPER, realizing choice optimization recently proposed in (Caroprese et al., 2007). CHOPPER supports the ASOch and ASOfcii semantics based on the concept of "choice", as a set of preference rules describing common choice options in different contexts, and the ASO semantics (Brewka et al., 2003), which valuates each preference rule separately. This paper outlines the architecture of the system, discusses aspects of the choice identification strategies and of the feasibility of choice options. Moreover, the comparison of the proposed approach with the other implementation approaches proposed in the literature is provided.