Aggregation functions and generalized convexity in fuzzy optimization and decision making

In this paper triangular norms and conorms are introduced and suitable definitions and properties are mentioned. Then, aggregation functions and their basic properties are defined. The averaging aggregation operators are defined and some interesting properties are derived. Moreover, we have extended concave and quasiconcave functions introducing t-quasiconcave and upper and lower starshaped functions. The main results concerning aggregation of generalized concave functions are presented and some extremal properties of compromise decisions by adopting aggregation operators are derived and discussed.