2018/12/18 by Santos, Ederson Moreira dos, Nornberg, Gabrielle
#Analysis of PDEs (math.AP) #FOS: Mathematics
paper · doi:10.48550/arxiv.1812.07161
We investigate symmetry properties of positive solutions for fully nonlinear uniformly elliptic systems, such as Fi (x,Dui,D2ui) +fi (x,u1, … , un,Dui)=0, 1 ≤ i ≤ n, in a bounded domain Ω in ℝN with Dirichlet boundary condition u1=…,un=0 on ∂Ω. Here, fi 's are nonincreasing with the radius r=|x|, and satisfy a cooperativity assumption. In addition, each fi is the sum of a locally Lipschitz with a nondecreasing function in the variable ui, and may have superlinear gradient growth. We show that symmetry occurs for systems with nondifferentiable fi's by developing a unified treatment of the classical moving planes method in the spirit of Gidas-Ni-Nirenberg. We also present different applications of our results, including uniqueness of positive solutions for Lane-Emden systems in the subcritical case in a ball, and symmetry for a class of systems with natural growth in the gradient.