Pawlak's approximations in Γ-semihypergroups

The Gamma-semihypergroup is a generalization of a semigroup, a generalization of a semihypergroup, and a generalization of a Gamma-semigroup. In this paper, we discuss the roughness of Gamma-subsemihypergroups and Gamma-hyperideals (bi-Gamma-hyperideals) in Gamma-semihypergroups. In addition, we consider rough sets with respect to the idempotent regular relations in a quotient Gamma-semihypergroup. The upper approximations with respect to Green's equivalence relations are derived in the context of Gamma-subsemihypergroups and Gamma-hyperideals. (C) 2010 Elsevier Ltd. All rights reserved.