Do We Need the Closed-World Assumption in Knowledge Representation?

Introduction Database systems and knowledge representation systems represent and reason about some aspect of the real world. In both it is common to separate the two functions of representation, i.e. describing the conceptual scheme and the actual data, and computation, i.e. answering of queries and manipulation of data. The database management system of a database system provides a data definition language to describe the conceptual scheme. The data definition language is used to describe the database in terms of a data model. Operations on the database require a specialized language, called a data manipulation language or query language. One of the most important data models is the relational model which describes the world in terms of atomic values and relations on the set of all atomic values. Data manipulation languages of the relational model comprise the relational algebra, and the domain and tuple relational calculi. The&lt