phrases similarities usually derived set theoretic operations sets common models standard boolean model extended boolean model fuzzy retrieval ''algebraic models'' represent documents queries usually vectors matrices tuples similarity query vector document vector represented scalar value vector space model generalized vector space model enhanced topic based vector space model extended boolean model latent semantic indexing aka latent semantic analysis ''probabilistic models'' treat process document retrieval probabilistic inference similarities computed probabilities document relevant given query probabilistic theorems like
Applied science Library and museum studies Information retrieval