摘要
设R■A是环的Frobenius扩张,其中A是右凝聚环,M是任意左A-模.首先证明了_AM是Gorenstein平坦模当且仅当M作为左R-模也是Gorenstein平坦模.其次,证明了Nakayama和Tsuzuku关于平坦维数沿着Frobenius扩张的传递性定理的"Gorenstein版本":若_AM具有有限Gorenstein平坦维数,则Gfd_A(M)=Gfd_R(M).此外,证明了若R■S是可分Frobenius扩张,则任意A-模(不一定具有有限Gorenstein平坦维数),其Gorenstein平坦维数沿着该环扩张是不变的.
Let R ■ A be a,Frobenius extension of rings,where A is right coherent.Let M be any left A-module.We first show that AM is Gorenstein flat if and only if the underlying R-module RM is Gorenstein flat.Then we prove a"Gorenstein version"of Nakayama and Tsuzuku's theorem on transfer of flat dimensions along Frobenius extensions:if AM has finite Gorenstein flat dimension,then Gfd_A(M)= Gfd_R(M).Moreover,it is proved that if R ■ S is a separable Frobenius extension,then for any A-module(not necessarily of finite Gorenstein flat dimension),its Gorenstein flat dimension is invariant along such ring extension.
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