Improved tolerance matrix attribute reduction algorithm

In rough set theory,knowledge reduction has been one of the key contents.In this paper a new tolerance matrix is defined relative to tolerance relation-based attribute reduction algorithm under incomplete information systems in related reference.It is able to reduce the number of conditional attributes which need to be concerned.At the same time,it is proved that the attribute reduction acquired from this new method is equivalent to the attribute reduction in related reference. An algorithm for attribute reduction is presented,the speed of attribute reduction in incomplete information systems is increased.