Divide and Conquer Strategies for Effective Information Retrieval

Techniques of information retrieval extract relevant documents in a collection, in response to a user query. As is well-known [2] information retrieval techniques based on exact literal matching, i.e., on direct comparisons between the columns of the term-document matrix and the query, may be inaccurate due to common problems of word usage such as synonymy and polysemy. Latent Semantic Indexing (LSI) [12] is a well-known method which was developed to deal with these difficulties. LSI projects the original term-document matrix into a reduced rank subspace by resorting to the Singular Value Decomposition (SVD). The comparison of the query with the documents is then performed in this subspace