投射余模的同调性质

The Homological Porperties of Injective Comodule

通过投射模的定义和它的一些等价刻画及郝志峰给出的H-投射余模,介绍了H-余自由余模,以及它的一些简单的性质,进而讨论了投射余模和余自由余模的关系.最后,还给出了H-投射余模是余自由的相关条件,以及,当char(K)=0且H=K[x1,…,xn]o时,每个有限余生成H-余模均为投射余模的结论.

In this paper, by using equivalent characteristic of projective module and definition of a H-projective comodule given by Zhifeng Hao, H cofree comodule and its simple properties are introduced, the relationship between H - projective comodule and H- cofree comodule is discussed. Finally, a condition of H - projective comodule to become cofree is given and it is proved that when Char（K） =0 and H= K[x1, x2,…,xn ]^o every finite cogenerated injective comodule is projective comodule.