Generalized upper and lower approximations in set-valued information systems

Under the framework of set-valued information system, based on application of quantifiers and OWA operator, the definition on upper and lower approximations is generalized to the common form associated with the parameter lambdaepsi [0, 1]. The advantage of such generalization is that it could be flexibly used by restriction of additional linguistic quantifier, and is favorable to the further discussion on knowledge reduction and rules extraction in such model.