Infinitely many radial solutions to a boundary value problem in a ball (Q1409661)

The paper deals with existence and multiplicity of radial solutions to the problem \[ \begin{cases} \nabla\cdot(a(|\nabla u|)\nabla u)+f(|x|,u)=0 &\text{in \(B\)},\\ u=0 & \text{on } \partial B, \end{cases} \] where \(B\) is a ball in \(\mathbb{R}^K,\) while \(f\) is defined in a neighbourhood of \(u=0\) and satisfies a sublinear growth condition as \(u\to 0\). The degree approach is used in combination with time-map techniques. The authors obtains also multiplicity results for nonlinearities of convex--concave type.