Double Obstacle Problems with obstacles given by non- Hamilton-Jacobi equations
arXiv:1201.4825 · doi:10.1007/s00205-012-0541-4
Abstract
We prove optimal regularity for the double obstacle problem when obstacles are given by solutions to Hamilton-Jacobi equations that are not . When the Hamilton-Jacobi equation is not then the standard Bernstein technique fails and we loose the usual semi-concavity estimates. Using a non-homogeneous scaling (different speed in different directions) we develop a new pointwise regularity theory for Hamilton-Jacobi equations at points where the solution touches the obstacle. A consequence of our result is that -solutions to the Hamilton-Jacobi equation are in fact provided that . This result is optimal and to the authors' best knowledge new.