Abstract: A system filters documents in a document set retrieved from a document store in response to a query. The system obtains a first set of logical forms based on a selected one of the query and the documents in the document set. The system obtains a second set of logical forms based on another of the query and the documents in the document set. The system then uses natural language processing techniques to modify the first logical forms to obtain a modified set of logical forms. The system filters documents in the document set based on a predetermined relationship between the modified set of logical forms and the second set of logical forms.

Abstract: Apparatus and accompanying methods for an information retrieval system that utilizes natural language processing to process results retrieved by, for example, an information retrieval engine such as a conventional statistical-based search engine, in order to improve overall precision. Specifically, such a search ultimately yields a set of retrieved documents. Each such document is then subjected to natural language processing to produce a set of logical forms. Each such logical form encodes, in a word-relation-word manner, semantic relationships, particularly argument and adjunct structure, between words in a phrase. A user-supplied query is analyzed in the same manner to yield a set of corresponding logical forms therefor. Documents are ranked as a predefined function of the logical forms from the documents and the query.