Rough set over dual-universes in general incomplete information system

For the universality of incomplete information and superiority of rough set over dual-universes, we research rough set over dual-universes in incomplete information system. In this paper, we provide a general character function in incomplete information system. Then lower and upper approximation operators of rough set over dual-universes in incomplete information system are constructed utilizing general character function. Basic properties of rough set over dual-universes in incomplete information system are studied. Relations between rough set over dual-universes rough set over dual-universes in incomplete information system are discussed. Also, some numerical examples are presented to illustrate theses concepts.