US Patent 7194461 Document and information retrieval method and apparatus

A data procassing unit in programmed to retrieve a document item and/or an information item from a plurality of document items and/or information items. Each of the items is identified by an index vector. The retrieval (15) is in response to a query (11) including plural query terms related to each other by Boolean logic. The program causes the data processing unit to transform the query into vector form through matrix calculations (12) and to measure the similarities of the item index vectors and the vector form of the query to determine which of the items correspond with the query.