TY - JOUR TI - Small supplements, weak supplements and proper classes AB - Let SS denote the class of short exact sequences E :0 -> A-> B ->C -> 0 of R-modules and R-module homomorphisms such that f (A)has a small supplement in B i.e. there exists a submodule K of M suchthat f (A) + K = B and f (A) ? K is a small module. It is shown that,SS is a proper class over left hereditary rings. Moreover, in this case,the proper classSS coincides with the smallest proper class containing the class of short exact sequences determined by weak supplementsubmodules. The homological objects, such as,SS-projective and SScoinjective modules are investigated. In order to describe the classSS,we investigate small supplemented modules, i.e. the modules each ofwhose submodule has a small supplement. Besides proving some closure properties of small supplemented modules, we also give a completecharacterization of these modules over Dedekind domains AU - DUR?GUN, Yılmaz AU - BÜYÜKAŞIK, Engin AU - ALİZADE, Rafail PY - 2016 JO - Hacettepe Journal of Mathematics and Statistics VL - 45 IS - 3 SN - 1303-5010 SP - 649 EP - 661 DB - TRDizin UR - http://search/yayin/detay/209056 ER -