%0 Journal Article %A Zhaohao Wang and Lan Shu %D 2012 %J International Journal of Mathematical and Computational Sciences %B World Academy of Science, Engineering and Technology %I Open Science Index 68, 2012 %T The Lower and Upper Approximations in a Group %U https://publications.waset.org/pdf/9259 %V 68 %X In this paper, we generalize some propositions in [C.Z. Wang, D.G. Chen, A short note on some properties of rough groups, Comput. Math. Appl. 59(2010)431-436.] and we give some equivalent conditions for rough subgroups. The notion of minimal upper rough subgroups is introduced and a equivalent characterization is given, which implies the rough version of Lagranges Theorem. %P 1147 - 1151