Vagueness and uncertainty in information retrieval: how can fuzzy sets help?

The field of fuzzy information systems has grown and is maturing. In this paper, some applications of fuzzy set theory to information retrieval are described, as well as the more recent outcomes of research in this field. Fuzzy set theory is applied to information retrieval with the main aim being to define flexible systems, i.e., systems that can represent and manage the vagueness and subjectivity which characterizes the process of information representation and retrieval, one of the main objectives of artificial intelligence.