Parallel covector field
= Parallel covector field
{title2=$\nabla_bk_a=0$}
A one-form $k$ with $\nabla_bk_a=0$. If $\ell=d\phi$ satisfies $\nabla_b\ell_a+\ell_a\ell_b=0$, then $k=e^\phi\ell=d(e^\phi)$ is parallel.
= Parallel covector field
{title2=$\nabla_bk_a=0$}
A one-form $k$ with $\nabla_bk_a=0$. If $\ell=d\phi$ satisfies $\nabla_b\ell_a+\ell_a\ell_b=0$, then $k=e^\phi\ell=d(e^\phi)$ is parallel.