Nonexistence of positive radial solutions for semipositone $ϕ$-Laplacian problems with superlinear reaction term

Abstract

The aim of this paper is to prove the nonexistence of positive radial solutions to the problem $-Δ_ϕu=λf(u)$, $x\in B_1(0)$, $u(x)=0$ on $|x|=1$, for $λ>0$ sufficiently large. Here, $ϕ$ is a continuous function, $Δ_ϕ$ denotes the $ϕ$-Laplacian operator which is defined by $Δ_ϕ(u):=div (ϕ(|\nabla u|) \nabla u)$, and $B_1(0)$ is the unit ball in $\mathbb{R}^N$, with $N>1$. Furthermore, $f$ is a continuous, nondecreasing function such that $f(0)<0$, and its behavior at infinity is intimately related to $ϕ$. Our findings are presented in a combined format, employing both an indirect argument and an energy analysis.