A polycyclic group G must be 4-generated if all abelian subgroups of each finite quotient of G are 3-generated.
设G是个多重循环群 ,若G的每个有限商群的Abel子群都是 3 -生成的 ,则G是 4元生成的 。
This paper shows that Z(M)=Z_G(M) (=Z(M)~=Z(M)_~) for all the graded modules M of an ordered group graded ring R.
证明了对于有序群分次环R上的分次模M,Z(M)=Z_G(M)(=Z(M)～=Z(M)_～),结果时于用奇异理想描述分次奇异理想具有一定意义。