Semi open fuzzy soft sets in Čech fuzzy soft closure spaces

This paper aims to introduce and investigate the notion of semi open (closed) fuzzy sets in Čech fuzzy soft closure spaces. The relationship between open (closed) fuzzy soft sets and semi open (closed) fuzzy soft sets has been discussed. Moreover, we show that the current notion of semi open fuzzy soft sets is reduced to semi open fuzzy soft sets in the associative fuzzy soft topological space of Čech fuzzy soft closure space. In addition, by using this new class of semi open (closed) fuzzy soft sets, a new type of closure operator, namely the fuzzy soft semi closure (interior) operator in Čech fuzzy soft closure spaces is introduced and its basic properties are investigated. Then, the notion of fuzzy soft semi exterior (boundary) is defined and its characterizations and properties are discussed with the fuzzy soft semi closure (interior) operator. Finally, the notions of Čech fuzzy soft semi continuous mappings and Čech fuzzy soft semi open (closed) mappings in Čech fuzzy soft closure spaces are presented, and their characteristics and properties are investigated.