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Answering queries with arithmetic expressions in heterogeneous systems

Answering queries using views has been the subject of numerous studies in database and information integration systems. In this work, we consider conjunctive queries with linear equality constraints. Such queries arise naturally in database applications, (heterogeneous) information integration, and in cooperative information systems. We propose a model for query answering in this context and introduce a corresponding rewriting algorithm that uses views to provide answers. We develop a prototype of this model in Java and describe its design and implementation details. This prototype provides a basis for us to further investigate important issues of data modeling and query processing in information integration systems.