Reasoning with vague truth

This paper presents a theoretical study of a formal technique for represent ing and manipulating partially true vague knowledge in computer. Our approa ch to the representation and manipulation of such truth-qualified vague kno wledge is based on the theory of possibility due to Zadeh. We have introduc ed a concept of similarity index, a measure of likeness of fuzzy sets of th e same type. Using the concept of similarity index, we have formulated a me thod for reasoning with partially truth-qualified vague knowledge. Examples have been considered to illustrate the usefulness of the proposed method. (C) 1999 Elsevier Science B.V. All rights reserved.