Although as such one dates back the idea of setting the area of soft computing to 1990, it was in 1994 that L.A. Zadeh established his worldwide accepted definition of soft computing. As it is well known since the seminal definition of a fuzzy set, different equivalent definitions of the concept have been proposed, analyzed and used. But, in spite of the former main constituents could be currently others and hence they should be revised, and the same cannot be said of soft computing. From this point of view, in order to narrow this gap, in this paper the role played until now by these main soft computing ingredients is analyzed, and then an original
José L. Verdegay, Ronald R. Yager, Piero P.