# The Amalgamated Duplication of a Ring Along a Semidualizing Ideal

### Maryam Salimi

Islamic Azad University, Teheran, Iran### Elham Tavasoli

Islamic Azad University, Teheran, Iran### S. Yassemi

Institute for Research in Fundamental Sciences (IPM), Tehran, Iran

## Abstract

Let $R$ be a commutative Noetherian ring and let $I$ be an ideal of $R$. In this paper, after recalling briefly the main properties of the amalgamated duplication ring $R⋈I$ which is introduced by D'Anna and Fontana, we restrict our attention to the study of the properties of $R⋈I$, when $I$ is a semidualizing ideal of $R$, i.e., $I$ is an ideal of $R$ and $I$ is a semidualizing $R$-module. In particular, it is shown that if $I$ is a semidualizing ideal and $M$ is a finitely generated $R$-module, then $M$ is totally $I$-reflexive as an $R$-module if and only if $M$ is totally reflexive as an $(R⋈I)$-module. In addition, it is shown that if $I$ is a semidualizing ideal, then $R$ and $I$ are Gorenstein projective over $R⋈I$, and every injective $R$-module is Gorenstein injective as an $(R⋈I)$-module. Finally, it is proved that if $I$ is a non-zero flat ideal of $R$, then fd $_{R}(M)=fd_{R⋈I}(M⊗_{R}(R⋈I))=fd_{R}(M⊗_{R}(R⋈I))$, for every $R$-module $M$.

## Cite this article

Maryam Salimi, Elham Tavasoli, S. Yassemi, The Amalgamated Duplication of a Ring Along a Semidualizing Ideal. Rend. Sem. Mat. Univ. Padova 129 (2013), pp. 115–127

DOI 10.4171/RSMUP/129-8