Radial solutions for elliptic boundary value problems with gradient terms in annular domains

The existence and uniqueness of radial solutions are discussed for elliptic boundary value problems ■ is continuous. In the general case where the nonlinear term f is not assumed to be non-negative, when f（ r,u,η） satisfies Nagumo-type condition on η, the existence of radial solutions is proved for the problem by using the method of lower and upper solutions and a truncating functional technique. Further, the uniqueness of radial solution is demonstrated under certain conditions.