Approximations by LR-type fuzzy numbers

Recently, many scholars investigated interval, triangular, and trapezoidal approximations of fuzzy numbers. These publications can be grouped into two classes: Euclidean distance class and non-Euclidean distance class. Most approximations in Euclidean distance class can be calculated by formulas, but calculating approximations in the other class is more complicated. Furthermore, approximations in Euclidean distance class can be divided into two subclasses. One is to study approximations of fuzzy numbers without constraints, the other one is to study approximations preserving some attributes. In this paper, we use LR-type fuzzy numbers to approximate fuzzy numbers. The proposed approximations will generalize all recent approximations without constraints in Euclidean class. Also, an efficient formula is provided.