Three-way decisions based on type-2 fuzzy sets and interval-valued type-2 fuzzy sets
This paper investigates three-way decisions of type-2 fuzzy sets and interval-valued type-2 fuzzy sets based on partially ordered sets. First, the partially ordered sets, constituted by fuzzy truth values and interval-valued fuzzy truth values, are established, respectively. They serve as the basic structures of three-way decision spaces. Second, several kinds of decision evaluation functions for type-2 fuzzy sets are defined. Three-way decision spaces and three-way decisions corresponding to each DEF are provided. In the end, a similar discussion is presented for interval-valued type-2 fuzzy sets. Examples are attached to each section to illustrate our models.