Multi-valued solutions to fully nonlinear uniformly elliptic equations

Entire Solutions to a Class of Fully Nonlinear Elliptic Equations

We study nonlinear elliptic equations of the form F (Du) = f(u) where the main assumption on F and f is that there exists a one dimensional solution which solves the equation in all the directions ξ ∈ Rn. We show that entire monotone solutions u are one dimensional if their 0 level set is assumed to be Lipschitz, flat or bounded from one side by a hyperplane.

Smooth approximations to solutions of nonconvex fully nonlinear elliptic equations

We show that fully nonlinear elliptic PDEs (which may not have classical solutions) can be approximated with integro-differential equations which have C solutions. For these approximated equation we prove a uniform C estimate. We also study the rate of convergence.

Symmetry results for viscosity solutions of fully nonlinear uniformly elliptic equations

Solvability of uniformly elliptic fully nonlinear PDE

We get existence, uniqueness and non-uniqueness of viscosity solutions of uniformly elliptic fully nonlinear equations of Hamilton-Jacobi-BellmanIsaacs type, with unbounded ingredients and quadratic growth in the gradient, without hypotheses of convexity or properness. Some of our results are new even for equations in divergence form.

Nonexistence of Positive Solutions for Some Fully Nonlinear Elliptic Equations

denote the kth elementary symmetric function, and let Γk denote the connected component of {λ ∈ R : σk(λ) > 0} containing the positive cone {λ ∈ R : λ1 > 0, · · · , λn > 0}. It is well known that Γk = {λ ∈ R : σl(λ) > 0, 1 ≤ l ≤ k}. Let S denote the set of n× n real symmetric matrices. For any A ∈ S we denote by λ(A) the eigenvalues of A. Throughout this note we will assume that Γ ⊂ R is an ope...