对偶余模函子()°和余反射余模

The Functor ()°of Dual Comodules and Coreflexive Comodules

本文给出对偶余模M°的结构刻划及（）°作为逆变函子的左正合性．同时引入余反射余模描述余反射余代数，由此研究余反射余代数的同调性质，证明当char（F）＝0时，F[x1，...，xn]°上的Serre猜测是成立的，即F[x1，...，xn]°的有限余生成内射余模均为余自由的．

In this paper we show the structure of dual comodule M0. We proof that the contravariant functor ()° is left exactness. We also introduce the coreflexive comodule to investigate the coreflexive coalgebras. Then we study some homological properties for corefiexive coalgebras. Finally let char (F) = 0 and C = F[x1, x2,...,xn]°, we show that every finitely cogenerated injective right C-comodules in cofree.