Countably thick modules

Ali Abdel-Mohsen and Mohammad Saleh

A. Abdel-Mohsen, Department of Mathematics, An-Najah University, Nablus, West Bank, Palestine

M. Saleh, Department of Mathematics, Birzeit University, P.O.Box 14, West Bank, Palestine



The purpose of this paper is to further the study of countably thick modules via weak injectivity. Among others, for some classes ${\mathcal M}$ of modules in $ \sigm$ we study when direct sums of modules from ${\mathcal M}$ satisfies a property $\mathbb P$ in $\sigm$. In particular, we get characterization of locally countably thick modules, a generalization of locally {\it q.f.d.}\ modules.

AMSclassification. 16D50, 16D60, 16D70, 16P40.

Keywords. Tight, weakly tight, weakly injective, countably thick, locally q.f.d., weakly semisimple.