Abstract
In this paper, we have use a fuzzy bitopological space (X, tau(1), tau(2)) to create a family tau(s)(ij) 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. Sostak. 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.