Coartinianess of local homology modules for ideals of small dimension
Abstract
Let ๐ be an ideal of a commutative noetherian ring R and M an R-module with Cosupport in V(๐). We show that M is ๐-coartinian if and only if ExtiR(R/๐,M) is artinian for all 0โคiโคcd(๐,M), which provides finite steps to examine ๐-coartinianess. We also consider the duality of Hartshorneโs questions: for which rings R and ideals ๐ are the modules H๐i(M)๐-coartinian for every artinian R-module M and all iโฅ0; whether the category ๐(R,๐)coa of ๐-coartinian modules is an abelian subcategory of the category of R-modules, and establish affirmative answers to these questions in the case cd(๐,R)โค1 and dimR/๐โค1.
Communicated by E. Jespers