right semi hereditary ring

This paper mainly uses fpn-injective right R-modules to investigate fpn-injective covers,gives a characterization of the existences of monomorphic fpn-injective covers of right R-modules,and proves that every R-module M has a monomorphic fpn-injective cover :E→M if and only if R is a right fpn-hereditary ring.

通过fpn-内射模类来研究模的fpn-内射覆盖,给出了单的fpn-内射覆盖的存在性刻画,证明了每个右R-模M都有单的fpn-内射覆盖φ:E→M当且仅当环R为右fpn-遗传环。