Null twist
= Null twist
{title2=$\widehat\omega_{ab}$}
The null twist is $\widehat\omega_{ab}=\widehat B_{[ab]}$. It vanishes for null generators orthogonal to a hypersurface by the <Frobenius theorem>.
= Null twist
{title2=$\widehat\omega_{ab}$}
The null twist is $\widehat\omega_{ab}=\widehat B_{[ab]}$. It vanishes for null generators orthogonal to a hypersurface by the <Frobenius theorem>.