In addition, a document can be relevant even if it does not mention the exact words used in the query. A user is generally not interested in the words, but in the concepts that those words represent. We report on an analysis of lexical ambiguity in information retrieval test collections, and on experiments to determine the utility of word meanings for separating relevant from non-relvant documents. Our research has examined different sources of evidence for distinguishing meanings. These sources can serve as a mechanism for splitting meanings apart, as well as bringing them together.
Similar distinctions hold for phrases and part of speech.
Any effort to deal with word meanings and information retrieval must take these distinctions into account. We will present the results of experiments with these sources of evidence, and our proposals for future work.