The Part Reductions in Information Systems

In this paper the definition of part reduction is proposed in information systems to describe the minimal description of a definable set by attributes of the given information system. The part reduction can present more optimum description of single decision class than the existing reductions and relative reductions. It is proven that the core of reduction or relative reduction can be expressed as the union of the cores of part reductions. So a deep insight is presented to the classical reductions and relative reductions of information systems so that a unified framework of the reductions of information systems can be set up. The method of discernibility matrix for computing reductions is also generalized to compute the part reductions in information systems.