Sample selection with rough set

In this paper sample selection with rough set is proposed in order to compress the discernibility matrix of a decision table so that only minimal elements in the discernibility matrix are employed to find reducts. First relative discernibility relation of conditional attribute is defined, indispensable and dispensable conditional attributes are characterized by their relative discernibility relations and key object pair set is defined for every conditional attribute. With the key object pair sets all the sample selections can be found. An example is employed in this paper to illustrate our idea of sample selection with rough set.