“…Therefore, theoretical foundations for reasoning algorithms of more expressive rough description logics including approximate concepts, number restrictions, nominals, inverse roles and role hierarchies are provided by the RDL AC . As far as future directions are concerned, these will include the approximate concept satisfiability and approximate concepts rough subsumption reasoning algorithms of rough description logics including number restrictions, nominals, inverse roles and role hierarchies, and an integration between approximate concepts and fuzzy DLs [17,41,42] or probabilistic DLs [12,28] based on fuzzy rough set theory [27,30,43,50,51] or probabilistic rough set theory [7,45,52], respectively. Furthermore, additional research effort can be focused on the investigation of the construction of approximate ontologies (or rough TBoxes) using formal concept analysis.…”