Rough set theory and formal concept analysis provide two different methods for data analysis. The notion of approximations can be introduced naturally into formal concept analysis. One of the issues studied in rough set theory is the approximation of undefinable sets through definable sets. An object-oriented concept consists of a definable set of objects and a definable set of properties. The rough concept lattice is the family of all such definable concepts. Give an arbitrary set of objects, it may not be the extension of an object-oriented concepts and attribute-oriented concepts, so we approximate it by the extension of object-oriented concept and attribute-oriented concept, respectively. Also, we construct the lower and upper approximations in approximable concept lattice, weak approximable concept lattice and rough approximable concept This work was supported by the National Science Foundation of China (No. 11401052), Hunan Provincial Education Department Foundation (No. 15B004) and the Science and Technology Program of Hunan of China (No. 2015RS4049).
