Using default logic for lexical knowledge

Lexical knowledge is knowledge about the morphology, grammar, and semantics of words. This knowledge is increasingly important in language engineering, and more generally in information retrieval, information filtering, intelligent agents and knowledge management. Here we present a framework, based on default logic, called Lexica, for capturing lexical knowledge. We show how we can use contextual information about a given word to identify relations such as synonyms, antinyms, specializations, and meronyms for the word. We also show how we can use mad-Line learning techniques to facilitate engineering a Lexica knowledgebase.