Abstract
In this paper, we give an answer to the following question of Kaplansky [14] in the local case: For which duo rings R is it true that every finitely generated left R-module can be decomposed as a direct sum of cyclic modules? More precisely, we prove that for a local duo ring R, the following are equivalent: (i) Every finitely generated left R-module is a direct sum of cyclic modules; (ii) Every 2-generated left R-module is a direct sum of cyclic modules; (iii) Every factor module of R R ⊕ R is a direct sum of cyclic modules; (iv) Every factor module of R R ⊕ R is serial; (v) Every finitely generated left R-module is serial; (vi) R is uniserial and for every non-zero ideal I of R, R/I is a linearly compact left R-module; (vii) R is uniserial and every indecomposable injective left R-module is left uniserial; and, (viii) Every finitely generated right R-module is a direct sum of cyclic modules.
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The research of the first author was in part supported by a grant from IPM (No. 92130413). This research is partially carried out in the IPM-Isfahan Branch.
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Behboodi, M., Behboodi Eskandari, G. Local duo rings whose finitely generated modules are direct sums of cyclics. Indian J Pure Appl Math 46, 59–72 (2015). https://doi.org/10.1007/s13226-015-0108-9
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DOI: https://doi.org/10.1007/s13226-015-0108-9