Let $R$ be a ring. I find myself considering $M=R^n$, as an $R$-module. If $a$ is not a zero divisor in $R$, it holds that
$\forall x \in M: ax=0 \Rightarrow a=0 \vee x=0$ .
For what kinds of modules in general is this the case?
Let $R$ be a ring. I find myself considering $M=R^n$, as an $R$-module. If $a$ is not a zero divisor in $R$, it holds that
$\forall x \in M: ax=0 \Rightarrow a=0 \vee x=0$ .
For what kinds of modules in general is this the case?