Rough Matroids Based on Dual Approximation Operators.

This paper presents the concept of lower and upper rough matroids based on approximation operators for covering-based rough sets. This concept is a generalization of lower and upper rough matroids based on coverings. A new definition of lower and upper definable sets related with an approximation operator is presented and these definable sets are used for defining rough matroids based on an approximation operator. Finally, an order relation for a special type of rough matroids is established from the order relation among approximation operators.