Notes on Baer modules and their dual
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Abstract
In this paper, we give new categorical characterizations of (dual-)Baer modules and then several applications of them are presented. Among other things, it is proved that a module $M_R$ is Baer if and only if for every $N\leq M_R$, $Rej^{-1}(N)$ is a direct summand of $M_R$. This shows that a module $M_R$ is Baer and co-retractable if and only if it is semisimple. Hence, over a ring Morita equivalent to a perfect duo ring, all Baer modules are semisimple. If $R$ is a right semi-hereditary and u.$\dim(R_R)$ is finite, then every finitely generated torsionless $R$-module $M$ is Baer. Dually, dual-Baer modules over certain rings are also investigated. If the $R$-module $M^+ $ = $Hom_{\Bbb Z}(M,{\Bbb Q}/{\Bbb Z})$ is Baer, then it is shown that $Hom_R(M,N)M$ is a pure submodule $M_R$ for any $N\leq M_R$.
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Ghaedan, N., & Vedadi, M.
(2022).
Notes on Baer modules and their dual.
Acta Mathematica Universitatis Comenianae, 91(4), 325-334.
Retrieved from http://www.iam.fmph.uniba.sk/amuc/ojs/index.php/amuc/article/view/1695/959
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