Generalizations of covering-based rough set models are made by the concept of intuitionistic fuzzy coverings.
The intuitionistic fuzzy rough set models based on intuitionistic fuzzy coverings are proposed. Firstly, the concepts
of an intuitionistic fuzzy set, an intuitionistic fuzzy covering and intuitionistic fuzzy logical operators are introduced.
Secondly, based on an intuitionistic fuzzy covering of a universe of discourse, two pairs of generalized lower and upper intuitionistic fuzzy rough approximation operators are constructed by means of an intuitionistic fuzzy triangular norm and an intuitionistic fuzzy implicator. Finally, basic properties of the generalized intuitionistic fuzzy rough approximation operators are investigated, and the duality between these approximation operators is examined.