Abstract:

The absolute reduction is a basic element of the rough set theory research. In the information view of rough sets there are still some drawbacks on the relevant theorems of the absolute reduction. Some existing theorems about the relationship between division and information entropy and theorems about the necessary and sufficient conditions of absolute reduction are analyzed. Then some new theorems about the relationship between division and conditional information entropy have been proposed. And the process of proving the theorems is given. Based on these new theorems, a necessary and sufficient condition of absolute reduction in the information view of RS is put forward. Then the relevant proving process is given too.

Key words: rough set, information entropy, conditional information entropy, absolute reduction