Let $\displaystyle A$ be an abelian group.
We know that all subgroups of $\displaystyle A$ are normal in $\displaystyle A$.
If $\displaystyle A$ is a free abelian group, are cyclic subgroups of $\displaystyle A$ also normal in $\displaystyle A$?
Let $\displaystyle A$ be an abelian group.
We know that all subgroups of $\displaystyle A$ are normal in $\displaystyle A$.
If $\displaystyle A$ is a free abelian group, are cyclic subgroups of $\displaystyle A$ also normal in $\displaystyle A$?