Searching Contexts in Rough Description Logics

In this paper, we present a method to obtain optimized query refinements of assertion axioms in the Rough Description Logic ALC. This method is based on the notion of discernibility matrix commonly used in the process of attributes reduction in the rough set theory. It consists of finding sets of concepts which satisfy the rough set approximation operations in assertion axioms. Consequently, these sets of concepts can be used to restrict or relax queries in this logic. We propose two algorithms to settle this problem of query refinement and show their complexity results.