Communications of the
Korean Mathematical Society CKMS

In this paper, we have use a fuzzy bitopological space $(X,\tau_{1},\tau_{2})$ to create a family $\tau_{ij}^{s}$ which is a supra fuzzy topology on $X$. Also, we introduce and study the concepts of $r-(\tau_{i},\tau_{j})$-generalized fuzzy regular closed, $r-(\tau_{i},\tau_{j})$-generalized fuzzy strongly semi-closed and $r-(\tau_{i},\tau_{j})$-generalized fuzzy regular strongly semi-closed sets in fuzzy bitopological space in the sense of \v{S}ostak. Also, these classes of fuzzy subsets are applied for constructing several type of fuzzy closed mapping and some type of fuzzy separation axioms called fuzzy binormal, fuzzy mildly binormal and fuzzy almost pairwise normal.

Keywords: fuzzy bitopological space, supra fuzzy topology, fuzzy binormal, fuzzy mildly binormal, fuzzy almost pairwise normal

MSC numbers: 54A40