Paper: Orthogonal Negation In Vector Spaces For Modelling Word-Meanings And Document Retrieval

ACL ID P03-1018
Title Orthogonal Negation In Vector Spaces For Modelling Word-Meanings And Document Retrieval
Venue Annual Meeting of the Association of Computational Linguistics
Session Main Conference
Year 2003
Authors

Standard IR systems can process queries such as “web NOT internet”, enabling users who are interested in arachnids to avoid documents about computing. The docu- ments retrieved for such a query should be irrelevant to the negated query term. Most systems implement this by reprocessing re- sults after retrieval to remove documents containing the unwanted string of letters. This paper describes and evaluates a the- oretically motivated method for removing unwanted meanings directly from the orig- inal query in vector models, with the same vector negation operator as used in quan- tum logic. Irrelevance in vector spaces is modelled using orthogonality, so query vec- tors are made orthogonal to the negated term or terms. As well as removing unwanted terms, this form of vector negation redu...