An update logic for information systems

•An update logic for information systems is proposed.•This logic can capture the flow of information as well as its effects on the approximations of sets.•A sound and complete deductive system for the logic is presented.•Decidability of the logic is proved for the case when attribute-value set is finite.

Updates in a knowledge base, given as an information system in rough set theory, may need to be made due to changes in (i) the set of attributes, (ii) attribute-values, or (iii) the set of objects (instances). In this article, we propose a logic for information systems which incorporates all these three aspects of updates. The logic can capture the flow of information as well as its effects on the approximations of concepts. A sound and complete deductive system for the logic is presented. The decidability issue is also discussed.