Restricted soft sets and bijective soft decision system

This thesis consists of eight chapters. In first chapter, the studies about the soft sets in the literature are given. In the second chapter, the basic definitions in the following chapters are mentioned. In third chapter, four different restrictions, obtained by using a non-empty subset α of U are examined, in detail. An application of α-intersection sets over a soft intersection groups is given in the fourth chapter. Here, the novel concept of the soft int-subgroup generated by α of a group is introduced and some properties are studied. Some related properties about generators of soft int-subgroups are investigated and illustrated by several examples. In fifth chapter, the bijective soft sets and its operations, a special form of soft sets, is introduced. In sixth chapter, a decision making method obtained using bijective soft operations and bijective soft matrices are given. In seven chapter, the notions of linguistic set and linguistic-valued function are given. Also, multi-bijective linguistic soft decision system is built. An application of this decision system is given in the last chapter.