Introducing Weighted Prototypes in Description Logics for Defeasible Reasoning

The representation of defeasible information in Description Logics is a well-known issue and many formal approaches have been proposed, mostly emerging from existing formalisms in non-monotonic logic. However, in these proposals little attention has been devoted to study their capability in capturing the interpretation of typicality and exceptions from an ontological and cognitive point of view. In this regard, we are currently studying defeasible reasoning as discussed in the linguistic and cognitive literature in order to understand the important desiderata of defeasibility in commonsense reasoning. In this paper, we provide an initial formalisation of a defeasible semantics for description logics which aims at fulfilling such desiderata. The solution is based on the idea of weighted prototypes, a new form of perceptron operator which is used to represent a notion of graded typicality of concept instances.