TY - JOUR TI - The α-interval valued fuzzy sets defined on α-interval valued set AU - Cuvalcioglu Gokhan AU - Bal Arif AU - Citil Mehmet JN - Thermal Science PY - 2022 VL - 26 IS - 102 SP - 665 EP - 679 PT - Article AB - In this study, α-interval valued set is defined whose elements are closed sub-intervals including α of unit interval that is I = [0, 1]. With different order relation on this set, the properties of α-interval valued set are examined. By the help of this order relation, it is shown that α-interval valued set is complete lattice. Negation function on α-interval valued set is given in order to study the theoretical properties of this set. By means of discussions on α-interval valued set, the fundamental features of α-interval valued set are studied. By the help of α-interval valued set, α-interval valued fuzzy sets are defined. The fundamental algebraic properties of these sets are examined. The level subsets of α-interval valued fuzzy sets are defined to give the relations between α-interval valued sets and crisp sets. With the help of this definition, some propositions and examples are given.