“…But this confining demand for equivalence limits the application scope of RST. For application purposes, many extensions of rough sets like fuzzy rough sets, rough fuzzy sets, IT2 fuzzy rough sets, IT2 rough fuzzy sets, tolerance rough fuzzy sets, rough sets based on Galois connections, soft rough fuzzy sets, and soft fuzzy rough sets have been studied (cf., [11,29,30,39,41,62,67]). RST has been proved an essential method in cognitive sciences, decision making, data mining, and artificial intelligence.…”