The lower and upper approximations in a hypergroup
This paper presents a relationship between rough sets and hypergroup theory. We analyze the lower and upper approximations of a subset, with respect to an invertible subhypergroup and we consider some particular situations. Moreover, the notion of a rough subhypergroup is introduced. Finally, fuzzy rough subhypergroups are introduced and characterized. (C) 2008 Elsevier Inc. All rights reserved.
hypergroup rough set invertible subhypergroup closed subhypergroup fuzzy set