on special submodule of modules
Abstract
let $r$ be a domain with quotiont field $k$, and let $n$ be a submodule of an $r$-module $m$. we say that $n$ is powerful (strongly primary) if $x,yin k$ and $xymsubseteq n$, then $xin r$ or $yin r$ ($xmsubseteq n$ or $y^nmsubseteq n$ for some $ngeq1$). we show that a submodule with either of these properties is comparable to every prime submodule of $m$, also we show that an $r$-module $m$ admits a powerful submodule if and only if it admits a strongly primary submodule. finally we study finitely generated torsion free modules over domain each of whose prime submodules are strongly primary.