# WHEN AN $\mathfrak{S}$-CLOSED SUBMODULE IS A DIRECT SUMMAND

• Wang, Yongduo (Department of Applied Mathematics Lanzhou University of Technology) ;
• Wu, Dejun (Department of Applied Mathematics Lanzhou University of Technology)
• Published : 2014.05.31
• 101 5

#### Abstract

It is well known that a direct sum of CLS-modules is not, in general, a CLS-module. It is proved that if $M=M_1{\oplus}M_2$, where $M_1$ and $M_2$ are CLS-modules such that $M_1$ and $M_2$ are relatively ojective (or $M_1$ is $M_2$-ejective), then M is a CLS-module and some known results are generalized.

#### Keywords

CLS-module;ejective module;ojective module

#### References

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