ABSTRACT.
In this talk, we study the boundary regularity of viscosity solutions to fully nonlinear degenerate or singular parabolic equations of the form
$$u_t = |Du|^\gamma F(D^2u)+f, \quad \gamma>-1.$$
The gradient-dependent degeneracy or singularity, together with the time derivative, poses significant difficulties compared to the elliptic case. We establish boundary $C^{1,\alpha}$ estimates for the Dirichlet problem under suitable structural assumptions on the operator and boundary data. The proof combines compactness arguments, barrier constructions, regularization techniques, and the boundary regularity of small perturbation solutions, together with the analysis of a model problem on a flat boundary. Our results unify and extend previous boundary regularity results and also provide a framework for studying boundary behavior in a broader class of nonlinear parabolic equations.