【摘要】 在含有缺省值的不完备性信息系统中,一部分对象无法确定的归入特定的类中,此时论域的邻域系统对于论域无法形成覆盖,只能形成论域的不完全划分。从概念上讲,对论域的不完全划分与对论域的覆盖都是对论域的拟划分的两个特例。作为基于覆盖的粗糙集模型的一种推广,将讨论基于拟划分的粗糙集模型中上下近似算子的若干性质,并且讨论了这个模型下近似算子的表示问题。更多还原

【Abstract】 In the incomplete information systems with unknown data or partly-known data.The objects can’t be precisely and complete classified.The neighborhood system can’t cover the universe.It is a incomplete partition of the universe.From the definition of them,the incomplete partition and the covering are the semi-partition of universe.As the generalization of the rough set based on covering,in this paper,the properties and the representation theorem of the rough sets based on the semi-partition are discussed.更多还原