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Acta Mathematica Vietnamica

On Semiregular Endomorphism Rings and the Dual of Yamagata’s Theorem

icon-email Tamer Koşan , Truong Cong Quynh

Abstract

In this paper, we characterize a module whose endomorphism ring is $\delta$-semiregular. For a right $R$-module $M$, we also obtained dual Yamagata’s theorem on the set $\nabla_{\delta}=\{f\in End(M)|f(M) \text{ is } \delta \text{ small in } M\}$.