English

Depth and Stanley depth of powers of the path ideal of a cycle graph

Commutative Algebra 2024-02-06 v3

Abstract

Let Jn,m:=(x1x2xm,  x2x3xm+1,  ,  xnm+1xn,  xnm+2xnx1,,xnx1xm1)J_{n,m}:=(x_1x_2\cdots x_m,\; x_2x_3\cdots x_{m+1},\; \ldots,\; x_{n-m+1}\cdots x_n,\; x_{n-m+2}\cdots x_nx_1, \ldots, x_nx_1\cdots x_{m-1}) be the mm-path ideal of the cycle graph of length nn, in the ring S=K[x1,,xn]S=K[x_1,\ldots,x_n]. Let d=gcd(n,m)d=\gcd(n,m). We prove that depth(S/Jn,mt)d1\operatorname{depth}(S/J_{n,m}^t)\leq d-1 for all tn1t\geq n-1. We show that sdepth(S/Jn,n1t)=depth(S/Jn,n1t)=max{nt1,0}\operatorname{sdepth}(S/J_{n,n-1}^t)=\operatorname{depth}(S/J_{n,n-1}^t)=\max\{n-t-1,0\} for all t1t\geq 1. Also, we give some bounds for depth(S/Jn,mt)\operatorname{depth}(S/J_{n,m}^t) and sdepth(S/Jn,mt)\operatorname{sdepth}(S/J_{n,m}^t), where t1t\geq 1.

Keywords

Cite

@article{arxiv.2303.15032,
  title  = {Depth and Stanley depth of powers of the path ideal of a cycle graph},
  author = {Silviu Balanescu and Mircea Cimpoeas},
  journal= {arXiv preprint arXiv:2303.15032},
  year   = {2024}
}

Comments

15 pages; correction of the main theorem