1. The problem statement, all variables and given/known data Assuming we used Hamilton's Principle to obtain the most general form of the Doppler shift for light. We said that it better be that kaua≠0. Show that this is the case. (Use local Minkowski coordinates) 2. Relevant equations Doppler shift equations kaua≠0 3. The attempt at a solution I am still trying to understand the re-derivation of the Doppler shift for light.