Fn-内射模与几乎优越扩张

Fn-injective Modules and Almost Excellent Extensions

将具有平坦维数≤n的模类Fn引入研究Fn-内射模与Fn-平坦模,得到了wD(R)≤n,Fm=Fn,Fn=P0,Fn=P1的等价刻画.在环的几乎优越扩张S≥R下,给出了Fn-内射模与Fn-平坦模的性质.

Use the class of modules with flat dimensions ≤n to introduce and investigate Jn-injective modules and -Jn-flat modules, and obtain some equivalent characterizations of the cases when wD（R） ≤ n, Jm = Jn ,Jn= ψ0 and Jn =ψ 1 respectively. Under an al-most excellent extension of rings, give some properties of Jn- injective modules and Jn-flat modules.