One-dimensional symmetry for solutions of quasilinear equations in
In this paper we consider two-dimensional quasilinear equations of the form and study the properties of the solutions u with bounded and non-vanishing gradient. Under a weak assumption involving the growth of the argument of (notice that is a well-defined real function since on ) we prove that is one-dimensional, i.e., for some unit vector . As a consequence of our result we obtain that any solution having one positive derivative is one-dimensional. This result provides a proof of...