FC-modules with an application to cotorsion pairs
Commentationes Mathematicae Universitatis Carolinae, Tome 50 (2009) no. 4, pp. 513-519
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Let $R$ be a ring. A left $R$-module $M$ is called an FC-module if $M^{+}= \operatorname{Hom}_{\mathbb{Z}}(M, \mathbb{Q}/\mathbb{Z})$ is a flat right $R$-module. In this paper, some homological properties of FC-modules are given. Let $n$ be a nonnegative integer and $\mathcal{FC}_{n}$ the class of all left $R$-modules $M$ such that the flat dimension of $M^{+}$ is less than or equal to $n$. It is shown that $({^{\bot}(\mathcal{FC}_{n}^{\bot})}, \mathcal{FC}_{n}^{\bot})$ is a complete cotorsion pair and if $R$ is a ring such that $\operatorname{fd}(({_RR})^{+})\leq n$ and $\mathcal{FC}_{n}$ is closed under direct sums, then $(\mathcal{FC}_{n}, \mathcal{FC}_{n}^{\bot})$ is a perfect cotorsion pair. In particular, some known results are obtained as corollaries.
Let $R$ be a ring. A left $R$-module $M$ is called an FC-module if $M^{+}= \operatorname{Hom}_{\mathbb{Z}}(M, \mathbb{Q}/\mathbb{Z})$ is a flat right $R$-module. In this paper, some homological properties of FC-modules are given. Let $n$ be a nonnegative integer and $\mathcal{FC}_{n}$ the class of all left $R$-modules $M$ such that the flat dimension of $M^{+}$ is less than or equal to $n$. It is shown that $({^{\bot}(\mathcal{FC}_{n}^{\bot})}, \mathcal{FC}_{n}^{\bot})$ is a complete cotorsion pair and if $R$ is a ring such that $\operatorname{fd}(({_RR})^{+})\leq n$ and $\mathcal{FC}_{n}$ is closed under direct sums, then $(\mathcal{FC}_{n}, \mathcal{FC}_{n}^{\bot})$ is a perfect cotorsion pair. In particular, some known results are obtained as corollaries.
Classification :
16D40, 16D80, 16E99
Keywords: character modules; flat modules; cotorsion pairs
Keywords: character modules; flat modules; cotorsion pairs
@article{CMUC_2009_50_4_a1,
author = {Guo, Yonghua},
title = {FC-modules with an application to cotorsion pairs},
journal = {Commentationes Mathematicae Universitatis Carolinae},
pages = {513--519},
year = {2009},
volume = {50},
number = {4},
mrnumber = {2583129},
zbl = {1203.16008},
language = {en},
url = {http://geodesic.mathdoc.fr/item/CMUC_2009_50_4_a1/}
}
Guo, Yonghua. FC-modules with an application to cotorsion pairs. Commentationes Mathematicae Universitatis Carolinae, Tome 50 (2009) no. 4, pp. 513-519. http://geodesic.mathdoc.fr/item/CMUC_2009_50_4_a1/