... Im Artin (theo B 2.2.11) Gi r0 l s t nhiờn tha Erj ,+s1= Erj ,+s2= = Ej , s 0 Do Ej , s Artin nờn Erj ,+s1 v suy Erj , s Artin 0 Lp li suy lun ny ta suy E2j , s := H mj ( H Rs ( M , N ) Artin ... M N P Khi ú ta cú N Artin v ch M v P Artin T iu ny ta suy nu dóy cỏc R -mụun M N P khp ti N v M , P l cỏc mụun Artin thỡ N cng l mụun Artin Mnh 1.1.6 Vnh R Artin v ch R Noether v dim ... l Artin + + T ton cu trờn ta suy H Rn + c ( M , N ) / m H Rn + c ( M , N ) Artin + + , N ) : Sup{i | H Ri ( M , N ) khụng Artin } Kớ hiu aR ( M = + + ( N ) : Sup{i | H Ri ( N ) khụng Artin...