Group decision making and consensus under fuzzy preferences and fuzzy majority

The authors present how fuzzy logic with linguistic quantifiers, mainly its calculi of linguistically quantified propositions, can be used in group decision making. The fuzzy linguistic quantifiers (exemplified by most, almost all,...) are employed to represent a fuzzy majority which is in many cases closer to a real human perception of the very essence of majority. Fuzzy logic provides here means for a formal handling of such a fuzzy majority which was not possible by using traditional formal apparatus. Assuming fuzzy individual and social preference relations, as it is commonly done, and employing in addition a fuzzy majority expressed by a fuzzy linguistic quantifier, the authors redefine solution concepts in group decision making, and present new ‘soft’ degrees of consensus.