Rotational hypersufaces in $E_1^4$ with generalized $L_k$ 1-type Gauss map

In this paper, we study the Gauss map of rotational hypersurfaces in 4-dimensional Lorentz-Minkowski space concerning the linear second order differential operators $L_1$ and $L_2$, where $L_1$ is usually called as the Cheng-Yau operator. We obtain some classifications of rotational hypersurfaces which have $L_k$-harmonic Gauss map, $L_k$-pointwise 1-type Gauss map and generalized $L_k$ 1-type Gauss map, where $k=1,2$.