摘要
设R是交换环,M是R-模.引入了模M的w-投射维数w-pd_R(M)和环R的w-弱finitistic维数w-f PD(R).给出w-f PD(R)=0的充分必要条件.证明了若R是w-凝聚环,M是有限表现R-模,则M有w-投射分解…→P_n→P_(n-1)→…→P_1→P_0→M→0,其中P_i是有限型的w-投射模,这里i=0,1,….最后,证明了若R是w-半遗传环,w-f PD(R)#1.
Let R be a commutative ring and M be an R-module.This paper introduces and studies the w-projective dimension w-pd_R(M)of an R-module M and the w-weak finitistic dimension w-f PD(R)of R.The sufficient and necessary condition of w-f PD(R)=0 is given.As an application,it is shown that if R is a w-coherent ring,M is of finitely presented type,then M has a w-projective resolution…→P_n→P_(n-1)→…→P_1→P_0→M→0,where P_iis w-projective of finite type for i=0,1,….Finally,if R is w-semi-hereditary,then w-f PD(R)#1.
引文
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