Extensions as Possible Worlds

This chapter presents a model-theoretic, path-based semantics for inheritance. Ambiguous inheritance hierarchies have multiple credulous extensions corresponding to their various possible disambiguations. Each of these extensions represents an unambiguous possible world-state and has a straightforward model-theoretic interpretation. Specificity can be seen as a preference over these multiple extensions; it is a path-based criterion for resolving certain types of inheritance ambiguity.