فهرست نشریات علمی دسترسی آزاد ایران

In this work we present a systematic study of $n$-layered modules which are closely related to $\Sigma$-modules. For each integer $n \geq 1$ we prove some results for $n$-layered modules concerning when $\Sigma$-modules are direct sum of countably generated modules. Moreover, we discover additional restriction which leads to coinciding of $n$-layered modules and $m$-layered modules for $n>m$.