{ "id": "2002.12170", "version": "v1", "published": "2020-02-26T09:10:53.000Z", "updated": "2020-02-26T09:10:53.000Z", "title": "Classification of radial solutions for elliptic systems driven by the $k$-Hessian operator", "authors": [ "Marius Ghergu" ], "comment": "21 pages. arXiv admin note: text overlap with arXiv:1808.00407", "categories": [ "math.AP" ], "abstract": "We are concerned with non-constant positive radial solutions of the system $$ \\left\\{ \\begin{aligned} S_k(D^2 u)&=|\\nabla u|^{m} v^{p}&&\\quad\\mbox{ in }\\Omega,\\\\ S_k(D^2 v)&=|\\nabla u|^{q} v^{s} &&\\quad\\mbox{ in }\\Omega, \\end{aligned} \\right. $$ where $S_k(D^2u)$ is the $k$-Hessian operator of $u\\in C^2(\\Omega)$ ($1\\leq k\\leq N$) and $\\Omega\\subset\\mathbb{R}^N$ $(N\\geq 2)$ is either a ball or the whole space. The exponents satisfy $q>0$, $m,s\\geq 0$, $p\\geq s\\geq 0$ and $(k-m)(k-s)\\neq pq$. In the case where $\\Omega$ is a ball, we classify all the positive radial solutions according to their behavior at the boundary. Further, we consider the case $\\Omega=\\mathbb{R}^N$ and find that the above system admits non-constant positive radial solutions if and only if $0\\leq m