Transaction Logic with Defaults and Argumentation Theories ⋆

Abstract. Transaction Logic (abbr., T R) [9,12] is a logic that gracefully integrates both declarative and procedural knowledge. It has proved itself as a powerful logic language for many advanced applications, including actions specification and planning in AI. In a parallel development, much work has been devoted to various theories of defeasible reasoning [19]. In this paper, we unify these two streams of research and develop T R DA —Transaction Logic with Defaults and Argumentation Theories, an extension of both T R and the recently proposed unifying framework for defeasible reasoning called logic programs with defaults and argumentation theories (LPDA) [53]. We show that this combination has a number of interesting applications, including specification of defaults in action theories and heuristics for directed search in AI problems such as planning. We also demonstrate the usefulness of the approach by experimenting with a prototype of T R DA and showing how heuristics expressed as defeasible actions can significantly reduce the search space as well as execution time and space requirements