GΘτi*τj-Fuzzy Closure Operator

In this paper, a new class of fuzzy ideal sets, namely the r-(tau(i), tau(j))-theta-generalized fuzzy ideal closed sets, is introduced for fuzzy bitopological spaces in Sostak sense. This class falls strictly in between the class of r-(tau(i), tau(j))-theta-fuzzy ideal closed sets and the class of r-(tau(i), tau(j))-generalized fuzzy ideal closed sets. Furthermore, by using the class of r-(tau(i), tau(j))-theta-generalized fuzzy ideal closed sets we establish a new fuzzy closure operator which generates fuzzy bitopological spaces in Sostak sense. Finally, the (i, j) strongly-theta-fuzzy ideal continuous, (i,j)-theta-generalized fuzzy ideal continuous and (i, j)-theta-generalized fuzzy ideal irresolute mappings are introduced, and we show the (i, j)-theta-generalized fuzzy ideal continuous properly fuzzy ideal bitopological spaces in Sostak sense (for short, fibtss) in between (j, i) strongly-theta-fuzzy ideal continuous and (i, j)-generalized fuzzy continuous mappings.