Locality in inheritance networks

Abstract

Touretzky proposed a rigorous theory of nonmonotonic inheritance in [ll] which was later found to be intractable [9] and to lead to counter-intuitive interpretation of certain networks [12]. Subsequently, there have been a number of proposals for semantics of inheritance networks done either through a translation into a general logical formalism [1,6,8], or by special path-based techniques [2,3,11]. As an alternative to these, we designed local theories of inheritance that are conceptually simple and computationally attractive [5]. Here, we formalize locality as it applies to inheritance networks and illustrate it with examples. We then generalize the notion of local semantics to what we call ground local semantics to further understand and clarify the relationship between our theories and the path-based theories. Our theories are both local and ground local; the skeptical semantics of [2] is not local, but is ground local,