𝒢Θτi⋆τj-Fuzzy Closure Operator
In this paper, a new class of fuzzy ideal sets, namely the [Formula: see text]-[Formula: see text]-[Formula: see text]-generalized fuzzy ideal closed sets, is introduced for fuzzy bitopological spaces in Šostak sense. This class falls strictly in between the class of [Formula: see text]-[Formula: see text]-[Formula: see text]-fuzzy ideal closed sets and the class of [Formula: see text]-[Formula: see text]-generalized fuzzy ideal closed sets. Furthermore, by using the class of [Formula: see text]-[Formula: see text]-[Formula: see text]-generalized fuzzy ideal closed sets we establish a new fuzzy closure operator which generates fuzzy bitopological spaces in Šostak sense. Finally, the [Formula: see text] strongly-[Formula: see text]-fuzzy ideal continuous, [Formula: see text]-[Formula: see text]-generalized fuzzy ideal continuous and [Formula: see text]-[Formula: see text]-generalized fuzzy ideal irresolute mappings are introduced, and we show the [Formula: see text]-[Formula: see text]-generalized fuzzy ideal continuous properly fuzzy ideal bitopological spaces in Šostak sense (for short, fibtss) in between [Formula: see text] strongly-[Formula: see text]-fuzzy ideal continuous and [Formula: see text]-generalized fuzzy continuous mappings.