Defeasible inheritance: A lattice based approach

AbstractWe describe here a model for inheritance reasoning based on the notion that a type can be described by two basic sets of characteristics—those that are necessary for the type and those that are typical for the type. All possible combinations of characteristics form a boolean lattice in which type descriptors can be placed relative to one another. Common lattice properties (such as transitivity of ]) combined with a default assumption operation form the basis for a theory of defeasible reasoning in inheritance networks. This paper gives a careful, but informal overview of the model, with several examples and many diagrams. For a more formal treatment, the interested reader is referred to the final chapters of [1]. The model allows a natural representation and a clean reasoning mechanism, at the same time as it adequately captures many of our intuitions regarding conclusions. It is also able to express some interesting nuances which are not available in other theories