Consensus modelling in group decision making: a dynamical approach based on Zadeh’s fuzzy preferences

The notion of consensus plays an important role in the theory of group decisions, particularly when the collective preference structure is generated by a dynamical process of aggregation of the single individual preference structures. In this process of preference aggregation each single decision maker gradually transforms his/her preference structure by combining it, through iterative weighted averaging, with the preference structures of the other decision makers. In this way the collective decision emerges dynamically as a result of the consensual interaction among the various decision makers in the group. From the point of view of applied mathematics, the models of consensual dynamics stand in the context of multi-agent complex systems, with interactive and non linear dynamics.