Logical foundation of fuzzy preferential systems with application to the electre decision aid methods

In this paper we introduce split truth/falseness semantics for a multi-valu ed logical processing of fuzzy preference modelling. Our approach takes as starting point the standard framework of fuzzy outranking relations as prop osed by the French multi-criteria decision aid community. Formal links betw een a given relational credibility calculus and associated truth polarizati on techniques will be discussed. The main result is the establishment of a multi-valued logical framework which allows us to naturally postpone any ne cessary defuzzification step to the end of the decision problem. Scope and purpose In this paper we propose an innovative multi-valued logical framework for p rocessing fuzzy preferential information as is common in the context of mul ti-criteria preference modelling. Our results concern a methodological and computational enhancement of the Electre decision aid methods as promoted b y the French school. of decision aid around the work of B. Roy and D. Bouys sou (Roy. Methodologie Multicritere d'Aide a la Decision. Paris: Economica, 1985; Roy and Bouyssou. Aide Multicritere a la Decision: Methodes et cas. Paris: Economica, 1993). The main achievement concerns the implementation o f a logically coherent defuzzification technique in order to make commute l ogical reasoning and defuzzification of preferential information. (C) 2000 Elsevier Science Ltd. All rights reserved.