sentence1: latent semantic analysis ( lsa ) is a mathematical technique used in natural language processing for finding complex and hidden relations of meaning among words and the various contexts in which they are found ( landauer and dumais , 1997 ; landauer et al , 1998 ) .
sentence2: latent semantic analysis ( lsa ) is a familiar technique that employs a word-by-document vsm ( cite-p-11-1-5 ) .