In the second part of this paper , using of linear compact and injective cogenerator so on , we discuss the relations between morita duality and weak morita duality . in [ 16 ] , n - absolutely pure modules , n - flat modules and n - coherent rings are defined 在文献[ 16 ]中，作者定义了n -绝对纯模和n -平坦模，并在此意义下将凝聚环推广硕士学位论文:弱内射模与弱morit 。
2.
Graded triangular extensions and graded trivial extensions over a ring are defined respectively , and the relation between them with grade morita dualities and their initial subrings with morita dualities is discussed . the graded selfduality of a polynomial ring in multivariables over a cogenerator ring as a graded ring of type different group i ?讨论了余生成子环上的多元多项式环作为不同群的分次环的分次自对偶问题，并证明了有自对偶的环的一种特殊的分次三角扩张有分次自对偶
