INFORMATION-RETRIEVAL BY LOGICAL IMAGING

The evaluation of an implication by Imaging is a logical technique dev eloped in the framework of modal logic. Its interpretation in the cont ext of a 'possible worlds' semantics is very appealing for IR. In 1989 , Van Rijsbergen suggested its use for solving one of the fundamental problems of logical models of IR: the evaluation of the implication d --> q (where d and q are respectively a document and a query represent ation). Since then, others have tried to follow that suggestion propos ing models and applications, though without much success. Most of thes e approaches had as their basic assumption the consideration that 'a d ocument is a possible world'. We propose instead an approach based on a completely different assumption: 'a term is a possible world'. This approach enables the exploitation of term-term relationships which are estimated using an information theoretic measure.