English

Asymptotic associate primes

Commutative Algebra 2019-07-30 v3

Abstract

We investigate three cases regarding asymptotic associate primes. First, assume (A,m) (A,\mathfrak{m}) is an excellent Cohen-Macaulay (CM) non-regular local ring, and M=Syz1A(L) M = \operatorname{Syz}^A_1(L) for some maximal CM A A -module L L which is free on the punctured spectrum. Let I I be a normal ideal. In this case, we examine when mAss(M/InM) \mathfrak{m} \notin \operatorname{Ass}(M/I^nM) for all n0 n \gg 0 . We give sufficient evidence to show that this occurs rarely. Next, assume that (A,m) (A,\mathfrak{m}) is excellent Gorenstein non-regular isolated singularity, and M M is a CM A A -module with projdimA(M)=\operatorname{projdim}_A(M) = \infty and dim(M)=dim(A)1 \dim(M) = \dim(A) -1 . Let I I be a normal ideal with analytic spread l(I)<dim(A) l(I) < \dim(A) . In this case, we investigate when mAssTor1A(M,A/In)\mathfrak{m} \notin \operatorname{Ass} \operatorname{Tor}^A_1(M, A/I^n) for all n0n \gg 0. We give sufficient evidence to show that this also occurs rarely. Finally, suppose A A is a local complete intersection ring. For finitely generated A A -modules M M and N N , we show that if ToriA(M,N)0 \operatorname{Tor}_i^A(M, N) \neq 0 for some i>dim(A) i > \dim(A) , then there exists a non-empty finite subset A \mathcal{A} of Spec(A) \operatorname{Spec}(A) such that for every pA \mathfrak{p} \in \mathcal{A} , at least one of the following holds true: (i) pAss(Tor2iA(M,N)) \mathfrak{p} \in \operatorname{Ass}\left( \operatorname{Tor}_{2i}^A(M, N) \right) for all i0 i \gg 0 ; (ii) pAss(Tor2i+1A(M,N)) \mathfrak{p} \in \operatorname{Ass}\left( \operatorname{Tor}_{2i+1}^A(M, N) \right) for all i0 i \gg 0 . We also analyze the asymptotic behaviour of ToriA(M,A/In)\operatorname{Tor}^A_i(M, A/I^n) for i,n0i,n \gg 0 in the case when II is principal or II has a principal reduction generated by a regular element.

Keywords

Cite

@article{arxiv.1709.06253,
  title  = {Asymptotic associate primes},
  author = {Dipankar Ghosh and Provanjan Mallick and Tony J. Puthenpurakal},
  journal= {arXiv preprint arXiv:1709.06253},
  year   = {2019}
}

Comments

34 pages

R2 v1 2026-06-22T21:47:45.579Z