让 R 是一枚 Noetherian 戒指, M Artinian R 模块,和 𝖒;公司 R M。然后 cograde R𝔭; Hom R (R 𝔭,M)=inf { 我| i (𝔭,M)> 0 }并且在哪儿 i (𝔭,M)是 i-th 关于 𝔭 的 M 的双鲈鱼数字;, cograde R𝔭 ; Hom R ( R 𝔭,M)是任何最大的 Hom R ( R 𝔭, M )伪在 𝔭 包含的co常规的顺序;R 𝔭, 和 fd R𝔭; Hom R (R 𝔭, M ) 是 R 𝔭-module Hom R (R 𝔭, M ) 。我们也在 cograde,合作尺寸和合作本地化模块的扁平的尺寸之中学习关系。
Let R be a Noetherian ring, M an Artinian R-module, and p ∈ CosRM. Thencograden. Homn(Rp, M) =-inf{i |πi(p, M) 〉 0} and πi(p, M) 〉 0 =〉 cogradeRpHomR(Rp, M) ≤ i ≤ fdRpHomR(Rp, M),where πi (p,M) is the i-th dual Bass number of M with respect to p, cogradeRpHomR (Rp ,M) is the common length of any maxima[ HomR(Rp, M)-quasi co-regular sequence contained in pRp, and fdRp HomR(Rp, M) is the flat dimension of the Rp-module HomR(Rp, M). We also study the relations among cograde, co-dimension and flat dimension of co-localization modules.