... noun phrases. Such weak interpretation is use- ful for tasks like information retrieval, document classification, and thesaurus extraction, and indeed forms the basis in the CLARIT system for ... the formulas: When /;'(W1,W2) increases, S(W1,W2) de- creases; When DF(W1, W2) increases, S(Wx, W2) de- creases; When AvgLDF(W~, W2) or AvgRDF(W~, W2) increases, S(W1, W2) increases; ... other hand, as a step toward the ideal of concept-based indexing, can ad- dress such a case directly. Indeed, it is interesting to note that the use of phrases as index terms has increased dramat-...