Boundary regularity for a general nonlinear parabolic equation in non-divergence form

Abstract

We characterize regular boundary points in terms of a barrier family for a general form of a parabolic equation that generalizes both the standard parabolic $p$-Laplace equation and the normalized version arising from stochastic game theory. Using this result we prove geometric conditions that ensure regularity by constructing suitable barrier families. We also prove that when $q<2$, a single barrier does not suffice to guarantee regularity.