Abstract
The primitive notions in rough set theory are lower and upper approximation operators defined by a fixed binary relation and satisfy many interesting properties. Many types of generalized rough set models have been developed in the literature. This paper investigates intuitionistic fuzzy rough sets resulted from approximations of intuitionistic fuzzy sets with respect to an arbitrary intuitionistic fuzzy approximation space. By employing two intuitionistic fuzzy implicators, a pair of lower and upper intuitionistic fuzzy rough approximation operators are first defined. Properties of intuitionistic fuzzy rough approximation operators are then presented.