Problem Set 3

Park City Mathematics Institute
Undergraduate Summer School 2018

Introduction to Harmonic Analysis

1. If $latex u$ is harmonic in the connected domain $latex \Omega$ and is not constant, then $latex u(\Omega)$ is open in $latex \R$.


2. Suppose $latex \Omega$ is bounded and that its boundary $latex \partial\Omega$ is connected. If $latex u$ is harmonic in $latex \Omega$, then $latex u(\Omega)\subset u(\partial\Omega)$.


3. A radial harmonic function on $latex \mathbb B$ is constant.


4. A positive harmonic function on $latex \R^d$ is constant.