摘要
本文旨在给出相对复盖与包络的特征刻划．作为应用，证明了：若Ｒ为任意环，０ＡＢＣ０为左Ｒ模正合列并且Ａ与Ｃ都有平坦复盖，则Ｂ有平坦复盖．
The purpose of this paper is to give characterizations of relative covers and envelopes. As an application, it is shown that for any ring R , if 0 A B C 0 is an exact sequence of left R modules, where both A and C have flat covers, then B has a flat cover.
出处
《数学学报（中文版）》
SCIE
CSCD
北大核心
1998年第3期609-616,共8页
Acta Mathematica Sinica：Chinese Series
基金
国家自然科学基金
江苏省自然科学基金
