ON THE EXISTENCE OF RADIAL SOLUTIONS OF QUASI-LINEAR ELLIPTIC-EQUATIONS

The authors give a method for proving the existence of (positive) radial solutions of quasi-linear elliptic equations taking into account the variation of lower-order terms. They find solutions of equations having oscillating nonlinearities under less restrictive conditions than those needed for variational or topological methods. They exhibit simple variational problems having a continuum of solutions. They also obtain invariant regions in C 1 for related parabolic problems.