ABSTRACT
This chapter is devoted to the study of a concrete class of fuzzy sets, namely those of the real line R. Fuzzy quantities are fuzzy subsets of R, generalizing ordinary subsets of R. In order to define operations among fuzzy quantities, we will invoke the extension principle, which was discussed in Chapter 2. This principle provides a means for extending operations on R to those of F(R). In later sections, we will look at special fuzzy quantities, in particular, fuzzy numbers and fuzzy intervals.
