This article mainly uses fpn-flat left R-modules to investigate the existences of relative preenvelopes of left R-modules.
通过fpn-平坦模类来研究模的相对预包络的存在性。
The existence of τ-flat test modules is proved, and some sufficient conditions for {τ-flat left R-modules} being preenvelope class or precove class are obtained.
证明了τ-平坦试验模的存在性,并给出了{τ-平坦模}构成预包络类或预覆盖类的几个充分条件。
Discussion on application of agar pre-embedding for preparing paraffin sections of tissues;
