Suppose \(\Omega \) is some closed, bounded domain in two spatial dimensions.
- Under what conditions does the equation \(\nabla ^2\phi =0\) in \(\Omega \), \(\mathbf {n}\cdot \nabla \phi =f\) on \(\partial \Omega \), have a solution? Is it unique?
- Find an integral equation for \(\phi \) on the boundary \(\partial \Omega \). Be as explicit as possible.
- Under what conditions does this integral equation have a solution?