2025/12/5
Amir Mafi

Amir Mafi

Academic rank: Professor
ORCID:
Education: PhD.
H-Index:
Faculty: Faculty of Science
ScholarId:
E-mail: a.mafi [at] uok.ac.ir
ScopusId: View
Phone: 33624133
ResearchGate:

Research

Title
On the Hilbert coefficients, depth of associated graded rings and reduction numbers
Type
JournalPaper
Keywords
Hilbert coefficient, minimal reduction, associated graded ring
Year
2021
Journal Journal of Commutative Algebra
DOI
Researchers Amir Mafi ، Dler Naderi

Abstract

Let $(R,\fm)$ be a $d$-dimensional Cohen-Macaulay local ring, $I$ an $\fm$-primary ideal of $R$ and $J=(x_1,...,x_d)$ a minimal reduction of $I$. We show that if $J_{d-1}=(x_1,...,x_{d-1})$ and $\sum\limits_{n=1}^\infty\lambda{({{I^{n+1}}\cap J_{d-1}})/({J{I^n} \cap J_{d-1}})=i}$ where i=0,1, then $\depth G(I)\geq{d-i-1}$. Moreover, we prove that if ${e_2}(I)=\sum\limits_{n = 2}^\infty{(n-1)\lambda({{I^{n }}}/{J{I^{n-1}}})}-2;$ or if $I$ is integrally closed and\\ ${e_2}(I)=\sum\limits_{n=2}^\infty{(n-1)\lambda({{I^{n}}}/{J{I^{n-1}}})}-3$, then ${e_1}(I)=\sum\limits_{n=1}^\infty{\lambda({{I^{n }}}/{J{I^{n-1}}})}-1,$ where the integers $e_i$ are the Hilbert coefficients of $I$. In addition, if $J$ is a minimal reduction of $I$ then we prove that the reduction number $r_J(I)$ is independent of $J$.