Cominimaxness with respect to ideals of dimension two and local cohomology

被引:2
|
作者
Karimirad, Hamidreza [1 ]
Aghapournahr, Moharram [1 ]
机构
[1] Arak Univ, Fac Sci, Dept Math, Arak 3815688349, Iran
关键词
Local cohomology; minimax module; cominimax modules; cofinite modules; FINITENESS PROPERTIES; COFINITENESS; MODULES; MINIMAX;
D O I
10.1142/S021949882150081X
中图分类号
O29 [应用数学];
学科分类号
070104 ;
摘要
Let R be a commutative Noetherian ring, a an ideal of R and M an R-module with dim M = d. We get equivalent conditions for top local cohomology module H-a(d)(M) to be Artinian and a-cofinite Artinian separately. In addition, we prove that if (R, m) is a local ring such that Ext(R)(i)(R/a, M) is minimax, for each i <= d, then Ext(R)(i)(N, M) is minimax R-module for each i >= 0 and for each finitely generated R-module N with dim N <= 2 and Supp(R)(N) subset of V (a). As a consequence we prove that if dim R/a = 2 and Supp(R)(M) subset of V(a), then M is a-cominimax if (and only if) Hom(R)(R/a, M), Ext(R)(1)(R/a, M) and Ext(R)(2)(R/a, M) are minimax. We also prove that if dim R/a = 2 and n is an element of N-0 such that Ext(R)(i)(R/a, M) is minimax for all i <= n + 1, then H-a(i)(M) is a-cominimax for all i < n if (and only if) Hom(R)(R/a, H-a(i)(M)) is minimax for all i <= n.
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页数:12
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