It is well known that "fuzziness"--informationgranulesand fuzzy sets as
one of its formal manifestations-- is one of important characteristics
of human cognitionandcomprehensionofreality. Fuzzy phenomena
existinnature and are encountered quite vividly within human society.
The notion of a fuzzy set has been introduced by L. A., Zadeh in 1965 in
order to formalize human concepts, in connection with the representation
of human natural language and computing with words. Fuzzy sets and fuzzy
logic are used for mod- ing imprecise modes of reasoning that play a
pivotal role in the remarkable human abilities to make rational
decisions in an environment a?ected by - certainty and imprecision. A
growing number of applications of fuzzy sets originated from the
"empirical-semantic" approach. From this perspective, we were focused on
some practical interpretations of fuzzy sets rather than being oriented
towards investigations of the underlying mathematical str- tures of
fuzzy sets themselves. For instance, in the context of control theory
where fuzzy sets have played an interesting and practically relevant
function, the practical facet of fuzzy sets has been stressed quite
signi?cantly. However, fuzzy sets can be sought as an abstract concept
with all formal underpinnings stemming from this more formal
perspective. In the context of applications, it is worth underlying that
membership functions do not convey the same meaning at the operational
level when being cast in various contexts.
