%A JI Ru-ya, WEI Ling, REN Rui-si, ZHAO Si-yu %T Pythagorean fuzzy three-way concept lattice %0 Journal Article %D 2020 %J JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE) %R 10.6040/j.issn.1671-9352.4.2020.241 %P 58-65 %V 55 %N 11 %U {http://lxbwk.njournal.sdu.edu.cn/CN/abstract/article_3362.shtml} %8 %X Pythagorean fuzzy set theory is introduced into fuzzy three-way concept lattice. The construction of Pythagorean fuzzy three-way concept lattice is studied under the Pythagorean fuzzy formal context. First, the relationships between objects and attributes are expressed by the membership degree and non-membership degree combined with the Pythagorean fuzzy set theory. On this foundation, the definition of the Pythagorean fuzzy formal context is given. Next, based on threshold α, β and the idea of three-way decision, the object sets(the attribute sets)are divided into three parts: positive region, negative region and boundary region. On this basis, the definitions and relevant theorems of two kinds of Pythagorean fuzzy three-way concepts(the object induced Pythagorean fuzzy three-way concept and the attribute induced Pythagorean fuzzy three-way concept)are given, and the corresponding Pythagorean fuzzy three-way concept lattices are constructed. Finally, the applications of Pythagorean fuzzy three-way concept lattice in real problems are explained in detail with examples.