Decision making and Atanassov’s approach to fuzzy sets J.T. Rodr´ ıguez, B. Vitoriano, J. Montero Faculty of Mathematics (Complutense University) Madrid 28040, Spain {jtrodrig,bvitoriano,monty}@mat.ucm.es Abstract In this paper we stress the role that decision making, and therefore an underlying binary (bipolar) approach, plays in Atanassov’s intuition- istic view of fuzzy sets. Moreover, we point out that such a bipolar view can be found in classical multicriteria models, Keywords: Multicriteria Decision Making, Atanassov’s Intuitionistic Fuzzy Sets. 1 Introduction Atanassov’s intuitionistic fuzzy sets [3] (see also [4, 5, 6, 11, 31]) has re- ceived great attention from the scientific community, showing its practical efficiency when applied to quite a number of problems. Although such a model has been also subject to a serious controversy because of the im- proper intuitionistic term and because of its equivalence to already existing models (see [32] and [13, 15], but also [7, 8]), we think with [20] that there are certain specific differences in conception that, when included in the model, can explain such a confusing situation. In particular, in [20] it is shown how those equivalent models become different when the underlying structured is taken into account within a classification framework (see [28] but also [1, 2]). It is also interesting to have a look to [12], where several formal generalizations of fuzzy sets [34] are reviewed together with some applications, as alternative models to be tried in those places Atanassov’s model has been successful, or not successful. The conflict about the name