On the theory and generalization of \Sigma-groups

In this work we present a systematic study of n-layered modules which are closely related to \Sigma-modules. For each integer n \geq ۱ 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.

کلیدواژه ها:

QTAG-modules ، n-layered modules ، high submodules