Two Phase Description Logic Reasoning for Efficient Information Retrieval

Abstract

Description Logics (DLs) [1] is family of logic languages designed to be a convenient means of knowledge representation. They can be embedded into FOL, but - contrary to the latter - they are decidable which gives them a great practical applicability. A DL knowledge base consists of two parts: the TBox (terminology box) and the ABox (assertion box). The TBox contains general background knowledge in the form of rules that hold in a specific domain. The ABox stores knowledge about individuals. For example, let us imagine an ontology about the structure of a university. The TBox might contain statements like “Every department has exactly one chair”, “Departments are responsible for at least 4 courses and for each course there is a department responsible for it”. In contrast, the ABox might state that “The Department of Computer Science is responsible for the course Information Theory” or that “Andrew is the chair of the the Department of Music”.