Separation of variables in equations of mean-curvature type

We obtain all the solutions of types u(x, y) = f(x) + g(y) and u(x, y) = f(x)g(y) for three known mean-curvature-prescribed equations, namely, the capillary equation, the translating soliton equation and the two-dimensional analogue of the catenary.

Mixed Initial-Boundary Value Problem for the Capillary Wave Equation

We study the mixed initial-boundary value problem for the capillary wave equation:iut+u2u=∂x3/2u, t>0, x>0; u(x,0)=u0(x), x>0; u(0,t)+βux(0,t)=h(t), t>0, where∂x3/2u=(1/2π)∫0∞sign⁡x-y/x-yuyy(y) dy. We prove the global in-time existence of solutions of IBV problem for nonlinear capillary equation with inhomogeneous Robin boundary conditions. Also we are interested in the study of the asymptotic behavior of solutions.