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On the finiteness and stability of certain sets of associated primes ideals of local cohomology modules

2012/11/07 by Cuong, Nguyen Tu, Van Hoang, Nguyen
#13C15 #13D07 #13D45 #Commutative Algebra (math.AC) #FOS: Mathematics

paper · doi:10.48550/arxiv.1211.1477

Abstract

Let (R,\frakm) be a Noetherian local ring, I an ideal of R and N a finitely generated R-module. Let k≥-1 be an integer and r=\depthk(I,N) the length of a maximal N-sequence in dimension >k in I defined by M. Brodmann and L. T. Nhan (Comm. Algebra, 36 (2008), 1527-1536). For a subset S⊆ \Spec R we set S_≥k=\p∈ S|dim(R/\p)≥k. We first prove in this paper that \AssR(HjI(N))≥ k is a finite set for all j≤r. Let \fN=⊕n≥ 0Nn be a finitely generated graded \fR-module, where \fR is a finitely generated standard graded algebra over R0=R. Let r be the eventual value of \depthk(I,Nn). Then our second result says that for all l≤r the sets \bigcup_j≤l\AssR(HjI(Nn))_≥k are stable for large n.

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