... representing the containment re-lation between the extents, two combination oper-ators (, ) corresponding to “and” and “or” op-erator of the boolean model, and ordering operator(✸) representing ... Japankmasuda@is.s.u-tokyo.ac.jpAbstractThis paper investigates an application ofthe ranked region algebra to informationretrieval from large scale but unannotateddocuments. We automatically annotateddocuments ... Retrieval Based on Region AlgebraKatsuya MasudaDepartment of Computer Science, Graduate School of Information Science and Technology,University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033,...