Translating solutions to the Gauss curvature flow with flat sides

Abstract

We derive local $C^2$ estimates for complete non-compact translating solitons of the Gauss curvature flow in ${\mathbb{R}}^3$ which are graphs over a convex domain $\Omega$. This is closely is related to deriving local $C^{1,1}$ estimates for the degenerate Monge-Ampére equation. As a result, given a weakly convex bounded domain $\Omega$, we establish the existence of a $C_{\text{loc}}^{1,1}$ translating soliton. In particular, when the boundary $\partial \Omega$ has a line segment, we show the existence of flat sides of the translator from a local a'priori non-degeneracy estimate near the free-boundary.