Lets $f:\mathbb{R}^2 \to \mathbb{R} $, where $f$ is harmonic, continuous and non-constant. How do I go about showing that the level curves of $f$ are smooth?
Thanks!
Lets $f:\mathbb{R}^2 \to \mathbb{R} $, where $f$ is harmonic, continuous and non-constant. How do I go about showing that the level curves of $f$ are smooth?
Thanks!