This M.Sc. thesis is based on the following paper. Ibrahim, Yasser, Nguyen, Xuan Hau, Yousif, Mohamed F., and Zhou, Yiqiang. Rings whose cyclics are -modules. J. Algebra Appl., 15(8):1650152, 18, 2016. Troughout this review of thesis, we assume that a ring is associative with an identity and modules are unital. Let e a ring. An -module is a -module if the sum of any two direct summands with zero intersection is again a direct summand.
