From intervals to fuzzy truth-values: adding flexibility to reasoning under uncertainty

In dealing with representing knowledge under uncertainty there is a sustained tendency to increase flexibility in order to avoid problems of inconsistency in the knowledge. Early uncertainty management systems dealt with single real values within a predefined range, soon interval valued approaches were proposed and more recently we have witnessed the introduction of fuzzy-interval valued approaches, i.e., possibility distributions and fuzzy truth-values. In this paper we describe these fuzzy set based approaches with an emphasis on the concept of fuzzy truth-value.Peer Reviewe