Concept Approximation in Concept Lattice

In this paper we present a novel approach to the concept approximations in concept lattice. Using the similar idea of rough set theory and unique properties of concept lattice, upper and lower approximations of any object or attribute set can be found by exploiting meet-(union-)irreducible elements in concept lattice, the approximations can be performed on the fly. We show that our approach is more natural and effective than existing approach.