Abstract
In this paper, we introduce (1, 2)*-fuzzy soft b-open sets and (1, 2)*-fuzzy soft b-closed sets in fuzzy soft bitopological space and exhibit the properties of (1, 2)*-fuzzy soft b- open sets. Then we discuss the relation with (1, 2)*-fuzzy soft regular- open, (1, 2)*-fuzzy soft pre-open, (1, 2)*-fuzzy soft semi-open, (1, 2)*-fuzzy soft alpha-open, and (1, 2)*-fuzzy soft beta-open in fuzzy soft bitopological space. Also, we introduce and investigate the concepts of (1, 2)*-fuzzy soft b-interior, (1, 2)*-fuzzy soft b-closure in fuzzy soft bitopological space and analyze the relations between these concepts.