Abstract. We study symmetry properties of viscosity solutions of fully nonlinear uniformly elliptic equations. We show that if u is a viscosity solution of a rotationally invariant equation of the form+ is the Pucci's sup-operator, plays the role of the linearized operator at u. In particular, we prove that if u is a solution in a radial bounded domain, if f is convex in u and if the principal eigenvalue of Lu (associated with positive eigenfunctions) in any half domain is nonnegative, then u is foliated Schwarz symmetric. We apply our symmetry results to obtain bounds on the spectrum and to deduce properties of possible nodal eigenfunctions for the operator M + .
IntroductionThis paper studies symmetry properties of solutions of fully nonlinear equations related to spectral properties of what, improperly, will be called the linearized operator. The question we would like to answer is, which symmetry features of the domain and the operator are inherited by the viscosity solutions of the homogeneous Dirichlet problemwhere Ω ⊂ R n , n ≥ 2, is a bounded domain and F is a fully nonlinear uniformly elliptic operator. For the purpose of this introduction, let us emphasise its limit of application. Indeed, as it is well known by the experts, the moving plane method cannot be applied if the domain is not convex in the symmetry direction, say e.g. if Ω is an annulus, or if the nonlinear term f (x, u) does not have the right monotonicity in the x-variable (see e.g.[21] for 2010 Mathematics Subject Classification. 35J60.