Higher-order nondivergence elliptic and parabolic equations in Sobolev spaces and Orlicz spaces

In this paper we obtain the global regularity estimates of the solutions in Sobolev spaces and Orlicz spaces for higher-order elliptic and parabolic equations of nondivergence form in the whole space. We only need to focus on the parabolic case since the corresponding result in the elliptic case can be obtained as a corollary.